Electronic surgical screwdriver

Abstract

The present invention relates to a handheld electrically powered surgical screwdriver with intelligent torque sensor and communication capability, designed to reduce surgeon fatigue and improve precision, efficiency and safety in fastener insertion. The invention also encompasses a system that integrates the screwdriver with external devices for real-time monitoring, control and mapping of data, and a method for utilizing the screwdriver and the system to enhance surgical outcomes.

Description

Electronic Surgical Screwdriver

[0001] The present invention relates to the field of surgical instruments, specifically to a handheld, electrically powered surgical screwdriver designed to rotate and apply torque to threaded fasteners, such as surgical screws, for insertion into bone tissue of varying hardness and density. The invention also encompasses an intelligent surgical system incorporating the screwdriver and a method for the use thereof.

[0002] The ongoing focus on reducing hospital costs necessitates increased efficiency. Concurrently, stringent quality requirements demand traceability of surgical products, materials, and methods, while patients expect the highest standards of treatment. Consequently, surgeons are required to perform surgery with greater precision and in shorter timeframes than before.

[0003] Certain surgeries, such as pelvic surgeries, present challenges due to limited workspace and poor visibility. These conditions can make the insertion of multiple or long fasteners using manual methods and tools both fatiguing and time-consuming. Such fasteners are often inserted in pre-drilled holes in the bone. Additionally, the precision of direction and centering is compromised when using hand-powered screwdrivers, as the axial force required during fastener insertion can lead to fatigue and reduced torque sensitivity for the surgeon.

[0004] Electrically powered screwdrivers can mitigate physical fatigue; however, they introduce challenges in monitoring fastener progression and torque feedback. It becomes difficult to determine when a fastener is sufficiently inserted into the bone and to control torque, especially given the variable hardness and thickness of bone. An additional challenge for the surgeon is avoiding damaging the bone threads made by the threaded fastener during insertion with the rotational power of a powered screwdriver.

[0005] Torque-limiting functions in powered screwdrivers can halt fastener rotation and insertion at predetermined maximum torque levels. However, once stopped, the tools require manual switching of the rotation direction or manual counter-rotation by the surgeon to partially withdraw the fastener and clean the threads made in the bone tissue. Repeated backward and forward rotations to penetrate hard bone tissue, while repeatedly engaging torque-limiting functions on a tool, is cumbersome. This process can result in excessive withdrawal and insertion rotations for each cleaning round, potentially wearing out the previously cut threads in the bone tissue.

[0006] Surgical fasteners are pre-packaged in sterile bags labelled with a manufacturer serial number that includes product information, ensuring traceability of materials and manufacturing methods. Currently, the information about the fasteners installed in a patient’s body is manually recorded into the electronic patient records post-surgery. This manual process is time- consuming and prone to errors. Furthermore, the information is neither utilized to monitor insertion length progress, nor to anticipate physical parameters and effects during surgery such as torque limits associated with specific fastener parameters, such as the fasteners length and thread pitch

[0007] The present invention addresses the challenges faced in surgical procedures by introducing a handheld powered surgical screwdriver designed to reduce surgeon fatigue and improve precision, efficiency and safety in fastener insertion. The invention also encompasses an intelligent system that integrates the screwdriver with external devices for real-time monitoring and control, and a method for utilizing the screwdriver and system to enhance surgical outcomes.

[0008] Unlike traditional powered screwdrivers, the inventive screwdriver is adapted to integrate with external devices for real-time monitoring and control. This allows for precise tracking of fastener progression and torque application for the surgeon, which is particularly beneficial in surgeries involving bones of varying hardness and thickness. Existing powered screwdrivers often have preset torque limits that require manual intervention to reverse the fastener for thread cleaning. The inventive screwdriver offers advanced torque control that adapts in real-time, reducing the need for manual adjustments and minimizing wear on bone threads.

[0009] By alleviating the need for manual change of direction of rotation and / or adjustment of torque settings on the tool itself, precision is improved and risk of losing connection and grip with the fastener and insertion alignment is reduced, which decreases operational time and reduces fatigue during complex procedures.

[0010] The casing of the screwdriver is designed to be steam and water-tight, capable of withstanding autoclave conditions. This ensures that the device remains sterile and durable, which is crucial for maintaining high standards of surgical care and preventing post-surgical infections.

[0011] The intelligent system incorporates the screwdriver and integrates with external devices for real-time monitoring and control. The system allows for the monitoring of fastener progression and torque control, especially in bones of varying hardness and thickness. The system can establish torque curves during fastener insertion in real-time, providing feedback to the surgeon and enhancing precision.

[0012] The invention also addresses the inefficiencies in manually recording information about the fasteners used in surgeries and makes use of the information during surgery. By automating this process, it reduces the risk of errors and enhances the traceability and monitoring of surgical outcomes.

[0013] Real-time monitoring and advanced torque control ensure that fasteners are inserted with greater accuracy, reducing the risk of misalignment and / or improper fixation. This precision is crucial for the stability and success of surgical procedures, particularly in complex surgeries involving bones of varying hardness. By streamlining the fastener insertion process and minimizing the need for manual adjustments, the invention can shorten the duration of surgeries. This reduction in operative time not only increase efficiency but can also decrease the risk of complications associated with prolonged anesthesia and surgery.

[0014] The intelligent system’s ability to monitor and control torque in real-time helps prevent over- tightening or under-tightening of fasteners, which can lead to bone damage or insufficient fixation. This enhances the overall safety of the procedure.

[0015] With more precise and stable fastener placement, patients are likely to experience better surgical outcomes, leading to faster recovery times and reduced postoperative complications. By alleviating the physical strain on surgeons, the device helps maintain their focus and precision throughout the procedure. This can lead to better surgical performance and outcomes.

[0016] Overall, this invention significantly enhances the efficiency, safety, and effectiveness of surgical procedures, contributing to better patient outcomes and higher standards of care.

[0017] The present invention is set forth and characterized in the main claims. According to a first aspect of the inventive concept, there is provided:

[0018] A handheld surgical electrically powered screwdriver for fastening a threaded fastener with a predefined insertion length (LINS) into bone tissue, wherein the screwdriver comprises:

[0019] a tool connector, configured to rotate a threaded fastener; a motor, configured to provide rotational power to the tool connector; a power supply, configured to provide power to the motor; a microcontroller or a PCBA (printed circuit board assembly) comprising the microcontroller including:a memory for storing characteristic data of the threaded fastener to be inserted, wherein the characteristic data include the predefined insertion length (LINS) and a thread pitch of the threaded fastener; andan integrated torque sensor for directly measuring a torque applied to the threaded fastener in real-time;

[0020] a housing at least partly housing the motor, the power supply and the micro controller; wherein the microcontroller is configured for:

[0021] monitoring a number of rotations X of the threaded fastener into the bone tissue to calculate and register an insertion displacement of the threaded fastener into the bone tissue; monitoring torque data collected from the integrated torque sensor in real-time; and stopping the rotation of the tool connector if:the insertion of the threaded fastener reaches the predefined insertion length (LINS); orthe integrated torque sensor registers a predefined torque limit value (TMAX).

[0022] The tool connector may be configured to rotate the threaded fastener by direct engagement with the fastener. Alternatively, the tool connector may be a chuck for connecting various types of rotating tools, such as a bit for engaging with the fastener or a bit-holders for easily interchangement of bit pieces of different shapes, or even drill pieces, milling pieces, or any other tools used with powered rotary tools in surgery. The bit, whether directly connected to the tool connector or connected via an intermediary bit-holder, may be of any type adapted to a fastener groove of the fastener head, such as cruciform Phillips or Pozidriv, hexagonal shapes like Allen or Torx grooves or any other suitable shape or standard.

[0023] The stopping of the rotation of the tool connector may be achieved by cutting the power to the motor, thereby halting the motor and the rotational power supply to the tool connector.

[0024] In one embodiment of the present invention the surgical screwdriver may further comprise a transformer for transforming a voltage from the power supply to the motor and wherein the micro controller or the PCBA comprising the microcontroller comprises is connected to a motor controller for controlling the voltage to the motor.

[0025] In a further embodiment, the surgical screwdriver may also further comprise a gear mechanism configured to transmit power from the motor to the tool connector. The tool connector may further be connected to the gear mechanism through an intermediate drive shaft.

[0026] In yet a further embodiment the power supply may have an elongated shape with a length and a width, and wherein the motor and gear mechanism is positioned in parallel at least partially along the length of the power supply. The length and width of the housing may then for example both be greater than the thickness of the casing. An elongated and optionally flattened shape provides a compact form factor of the tool to enable operation of the tool when workspace is limited, and high precision hand-held handling.

[0027] In another embodiment, the surgical screwdriver may be configured such that, if the screwdriver is stopped due to reaching the predefined torque limit value (TMAX), the screwdriver performs a cycle of automatically reversing the rotation of the threaded fastener a predefined number of reverse rotations Z corresponding to a reverse displacement length, thereby cleaning threads in the bone tissue, followed by resuming the initial forward rotation of the threaded fastener. The predefined number of reverse rotation Z may for example be ¼ of a turn, ½ a turn, ¾ of a turn, 1, 2, 3, 4, 5 turns or more and any value in-between, such as ½ a turn or 1 turn in an example embodiment. The cycle (of reverse and forward rotation) may be repeated a maximum number of cycles Y if no further insertion displacement of the threaded fastener beyond a position where the cycle was initiated is registered by the micro controller.

[0028] The position where the cycle started is reached by the cycle when the number of forward rotations following the number of reverse rotations equals in number of rotations. The maximum number of cycles Y may for example be 1, 2, 3, 4, 5 times or more, such as 1 or 2 times in an example embodiment. The predefined number of reverse rotations Z and the maximum number of reversing cycles Y may be chosen based on what the bone tissue may sustain without wearing the threads, comprising a number of factors, such as the characteristics of the threaded fastener being used, whether a hole for the fastener has been pre-drilled and if so the diameter of such a hole, the density of the bone, the insertion progress length, etc.

[0029] In yet another embodiment, the micro controller or PCBA comprising the microcontroller may comprise a wireless communication device, such as Wifi, Bluetooth, Infrared, cellular, or NRF, configured to receive at least the characteristic data of the threaded fastener from an external unit.

[0030] In an additional embodiment, the integrated torque sensor may comprise at least one of: a current sensor, measuring current drawn by the motor to calculate a torque; a strain gauge, attached to a gear mechanism forming part of the surgical screwdriver, the gear mechanism being configured to transmit power from the motor to the tool connector; and a rotary encoder for measuring the angular displacement and rotational speed of the tool connector. A strain gauge may be configured in a Wheatstone bridge circuit for signal amplification and noise reduction.

[0031] In a further embodiment the surgical screwdriver may comprise a user activated control system, in signal communication with the micro controller, the user activated control system being configured to at least set the tool connector in rotation. The user activated control system may comprise at least one button activated by pressure, and preferably at least two buttons configured for activating opposite direction of rotation of the tool connector. Keeping a button depressed continues rotation of the tool connector, while releasing a button deactivates rotation.

[0032] According to a second aspect of the inventive concept, there is provided a system comprising:

[0033] the surgical screwdriver of the present invention, wherein the system comprises an external control system in signal communication with the micro controller for controlling and monitoring the operation of the surgical screwdriver.

[0034] In one embodiment, the surgical system, further comprises a graphical user interface, wherein the external control system is configured to gain access to the characteristic data stored in the memory and to display at least part of the characteristic data on the graphical user interface.

[0035] According to a third aspect of the inventive concept, there is provided:

[0036] A method for inserting surgical fasteners in bone tissue, by using the surgical screwdriver according to the invention or the surgical system according to the invention, comprising the steps of: monitoring the insertion displacement; monitoring the torque data; and stopping the rotation of the tool connector if:the insertion of the threaded fastener reaches the predefined insertion length (LINS); orthe integrated torque sensor registers a predefined torque limit value (TMAX).

[0037] In one embodiment the surgical screwdriver further comprises a user activated control system, in signal communication with the micro controller, the user activated control system comprises at least one button activated by pressure, wherein the method further comprises the step of exerting a pressure on the at least one button to activate and maintain rotation of the tool connector.

[0038] In a further embodiment, the method further comprises displaying at least one of: the insertion displacement; and the torque data; on the graphical user interface in real-time.

[0039] The inventive concept, some non-limiting embodiments, and further advantages of the present invention will now be described with reference to the drawings in which:Fig.1

[0040] is a perspective view of a powered surgical screwdriver (1) according one embodiment of the present invention.Fig.2

[0041] is a sectional view of the powered surgical screwdriver ofillustrating example components of the screwdriver.Fig.3

[0042] is a block diagram of the electronic and main components of the powered surgical screwdriver ofand 2 and their connections.Fig.4

[0043] is a schematic drawing of a surgical fastener (30).Fig.5

[0044] shows a cross-sectional view of an upper part of a femur (40) and exemplary torque curves established by the system following the fastener insertion length progression in bone tissue according one embodiment of the present invention.Fig.6

[0045] shows the curve inin more detail.Fig.7

[0046] shows a user interface for tool control and settings according to one embodiment of the present invention.Fig.8

[0047] shows an exemplary display of input data and data monitoring according to one embodiment of the present invention.Fig.9

[0048] shows an exemplary display of input data and data monitoring according to one embodiment of the present invention.Fig.10

[0049] shows a system according to one embodiment of the present invention.Fig.11

[0050] illustrates a flow diagram of an algorithm used by the system to initialize the screwdriver according to one embodiment of the present invention.Fig.12

[0051] illustrates a flow diagram of an algorithm used by the system during operation of the screwdriver according to one embodiment of the present invention.

[0052] The following description provides detailed descriptions of example embodiments with reference to the drawings, serving as examples of the invention’s principles. However, the scope of the invention is not limited to these embodiments and the term “present invention” is used to discuss these exemplary embodiments for explanatory purposes and does not restrict the scope of the claimed invention.

[0053] DEFINITIONS

[0054] The following terms are used in the description and claims and examples of meanings are given below.

[0055] “Threaded fastener” or “fastener” is used for a variety of components designed to hold parts together by means of threads, such as screws, bolts, studs or threaded rods threaded on both ends and similar.

[0056] “External device(s)” are devices to which the screwdriver may establish contact with, preferably through wireless connection(s). Example of external devices are tablet(s) and information screens, PC(s), workstation(s) etc.

[0057] “Wireless connection(s)” uses wireless data connections between network nodes transfer of information such as Bluetooth, Wifi, cellular (4G / 5G), infrared, NRF etc.

[0058] “GUI” is short for Graphic User Interface and comprises for example tablet or PC interfaces where the user of the tool may interact with the tool either through direct touch buttons on a display or a keyboard or keypad connected to the display and / or tool.

[0059] “Microcontroller” should be understood as a wide common term for a small integrated circuit, such as comprising a central processing unit (CPU), memory, parallel input and output interfaces, a clock generator, one or more analog-to-digital converters, and serial communication interfaces, etc.. The term may also encompass a PCBA (printed circuit board assembly) comprising such a microcontroller.

[0060] THE SCREWDRIVER

[0061] andillustrate a first embodiment of a surgical screwdriver 1 according to the present invention. The screwdriver 1 comprises a casing 2 with at least one button 3, a tool connector 4, and a bit 5 for engaging with a surgical fastener 50. The casing is designed to be steam and water-tight and may be made of metal, such as stainless steel or aluminium, composite material or plastics, which together with the mentioned components make up a unit capable of withstanding standard autoclave conditions, such as saturated steam at temperatures and pressures of at least 121°C (250°F) and 10,3 kPa (15 psi) for at least 30 minutes.

[0062] As shown in, the screwdriver may include more than one button, such as two buttons 3 for activating rotation in either (right / left or clockwise / counterclockwise) direction of the tool connector 4 with bit or bit-holder 5. In an embodiment with one button a single click activates the motor in a clockwise rotation and two consecutive clicks activates the motor in a counter- clockwise rotation. In an embodiment with two buttons, each button may be dedicated to opposite rotation directions. The tool connector 4 can be a chuck for connecting various types of rotating tools, such as bits for engaging with fasteners, bit holders for easy interchange of bit pieces of different shapes, drill pieces, milling pieces, or any other tools used with powered rotary tools in surgery. The bit 5, whether directly connected to the tool connector 4 or connected via an intermediary bit holder, may be of any type adapted to the fastener groove of the fastener head, such as cruciform Phillips or Pozidriv, hexagonal shapes like Allen or Torx grooves or any other suitable shape or standard.

[0063] provides a sectional view of the screwdriver shown in, illustrating the internal main components within the casing 2. These components include a motor 10, an optional battery or power connector 12, an optional gearbox 11, and a microcontroller 13 which may include various sensors and devices including torque sensor capabilities. In the embodiment ofan optional drive shaft 14 connects the gearbox 11 to the tool connector 4, to which a bit 5 or bit holder 5 may be attached. In this embodiment, the casing also includes a removable lid 21 for access to a removable battery 12 and sealing plugs 20 to protect the electronics and movable parts from moisture. Depending on the type of motor used, battery or power capacity, and the shape of the casing, the motor 10 may alternatively be directly coupled to the tool connector 4 in a direct drive fashion. In yet another alternative, the motor 10 may be coupled to the tool connector 4 via the optional drive shaft, omitting a gearbox 11.

[0064] Some main components will be described in further detail below.

[0065] THE MICROCONTROLLER

[0066] The microcontroller 13 may comprise and / or be connected to various sensors and controllers, including torque sensors, current sensors, and possibly strain gauges. These sensors may provide real-time data on the torque being applied by the screwdriver.

[0067] shows in more details examples of components that may be integrated and / or connected to the Microcontroller 13 as a block diagram.

[0068] The microcontroller 13 comprises a microprocessor or CPU (central processing unit) 130 and continuously processes the data from one or more torque sensors 32 to monitor the torque in real-time. It uses this information to make immediate adjustments to the motor’s operation. To control the operation of the motor, the microcontroller may comprise or be connected to a motor controller 134 which is connected to a transformer 121 that regulates the power fed to the motor 10 from the battery or power supply 12.

[0069] The microcontroller 13 is programmed with specific torque thresholds stored in the memory 131, (such as torque limits 201, 202, 203, and 204 shown in). It compares the real-time torque data against these thresholds to determine the appropriate actions. When the torque exceeds a predefined limit, the microcontroller initiates an automatic thread cleaning process. This involves reversing the motor 10 for a defined number of rotations to clear debris from the fastener threads before resuming forward rotation. The microcontroller 13 logs the number of rotations in its memory 131 and calculates the insertion displacement based on the fastener’s thread pitch and the number of rotations. This helps in tracking the progress of the fastener insertion as the total length and the predetermined insertion length of the fastener is also stored in the memory 131.

[0070] The microcontroller 13 provides real-time feedback to the user interface on any connected devices, such as a tablets 400 or aPC / terminal 600. This includes displaying torque curves, insertion length, and other relevant data. If the torque exceeds the maximum threshold or if any anomalies are detected, the microcontroller 13 sends alerts to the user. This helps the surgeon make informed decisions during procedures and take immediate corrective actions if necessary.

[0071] The microcontroller 13 may also comprise one or more wireless units 133 supporting wireless communication protocols such as Bluetooth, Wi-Fi, NFC (Near-Field Communication) and RFID (Radio-frequency Identification). This allows it to communicate with external devices for data exchange, remote control, and real-time monitoring. The microcontroller logs all relevant data during the fastener insertion process and can transmit this data to hospital information systems for record-keeping and analysis.

[0072] An example of a suitable microcontroller 13 for these tasks in a small form factor is the Seeed Studio XIAO nRF52840 Sense. This microcontroller has a footprint of 21x17.5 mm, ten control pins, sufficient memory and speed for calculations, and supports wireless Bluetooth communication. It also includes a NFC sensor, which can automatically detect passive NFC chips that operate without power. The microcontroller is preferably accompanied by at least two sensors and one actuator for performing torque monitoring.

[0073] In one embodiment, the workflow of the microcontroller 13 may be as follows:During an initialization phase, the microcontroller initializes the system and establishes communication with external devices. It sets up the torque thresholds and other operational parameters based on user input.As fastener insertion initiates, the microcontroller 13 continuously monitors the torque data from the sensors. It logs the number of rotations and calculates the progression of the insertion length status.For torque monitoring, the microcontroller compares the real-time torque data against the predefined thresholds stored in the memory 131. If the torque exceeds the maximum limit while the full predefined insertion length has not been reached, it stops the forward rotation and may initiate a thread cleaning process.During the thread cleaning process, the microcontroller reverses the motor for a defined number of rotations to clear debris from the threads. It then resumes forward rotation and continues monitoring the torque.Upon completion, once the insertion of the fastener 50 reaches the predefined insertion length (LINS), or a maximum repeated thread cleaning processes have been performed without further insertion progression, the microcontroller stops the motor and locks it in place. It logs all the data and transmits it to the connected devices for record-keeping.

[0074] The benefits of using a microcontroller 13 is ensuring precise control over the fastener insertion process by continuously monitoring and adjusting the torque. It automates critical functions such as thread cleaning and stopping the motor at the correct insertion length, reducing the need for manual intervention. The microcontroller provides real-time feedback and alerts, helping surgeons make informed decisions during the procedure. It logs all relevant data and facilitates seamless communication with external devices and hospital information systems.

[0075] In summary, the microcontroller 13 is the “brain” of the surgical screwdriver, orchestrating all aspects of torque monitoring, control, and communication to ensure a safe, efficient, and precise fastener insertion process.

[0076] TORQUE SENSOR

[0077] The screwdriver 1 is designed for torque monitoring wherein the torque sensor 32 is a critical component of the surgical screwdriver, enabling precise control and monitoring of the torque applied during fastener insertion. The torque sensor 50 can be implemented in several ways as described in more detail below.

[0078] Anintegrated torque sensorcan be built into the screwdriver’s drive mechanism, directly measuring the torque applied to the fastener. It provides real-time feedback to the microcontroller 13, allowing for immediate adjustments to the motor’s operation. Such sensors can be based on twist angle, by measuring the phase difference between two position sensors mounted at each end of a shaft, or by magnetic sensors, measuring the difference in magnetic fields resulting from the twisting of a metallic shaft.

[0079] Torque can also be indirectly measured throughcurrent sensingby monitoring the current drawn by the motor. Since torque is proportional to the current in direct current (DC) motors, this data is used to estimate the torque wherein a current sensor can be used to provide an accurate estimate of the torque. This method may involve a sensor integrated into the PCBA (printed circuit board assembly) of the microcontroller or using a current sensor circuit on the motor’s power supply line to measure the current and the microcontroller calculates the corresponding torque. This involves converting the electrical signals from the sensors into torque values using predefined algorithms and calibration data.

[0080] Astrain gaugecan be attached to the drive shaft 14 or gear mechanism 11 to measure the deformation caused by the applied torque. The strain gauge converts this deformation into an electrical signal, which is then processed by the microcontroller 13 to determine the torque.

[0081] Strain gauges may provide precise torque measurements in the surgical screwdriver. They are attached to the drive shaft or gear mechanism, measuring the torsional strain experienced during fastener insertion. This strain causes a change in the strain gauge’s electrical resistance, which is proportional to the applied torque. This information is processed by the microcontroller to ensure optimal performance, safety, and efficiency during delicate surgical procedures.

[0082] The strain gauges are configured in a Wheatstone bridge circuit to amplify the signal and reduce noise. The resulting voltage change is processed by the microcontroller, which converts it into a digital format and calculates the torque using calibration data and algorithms. To allow the motor axle to rotate continuously, wire connection is not desired and slip rings or wireless telemetry are used instead.

[0083] Strain gauges enable real-time monitoring and immediate adjustments, ensuring optimal performance, are durable, withstand mechanical stresses, and are compact, making them ideal for integration into surgical tools.

[0084] During initialization, strain gauges are calibrated, and the initial resistance is measured. The microcontroller sets up the Wheatstone bridge circuit for data acquisition. As the screwdriver inserts the fastener 50, the drive shaft 14 experiences torsional strain, causing the strain gauges to change their electrical resistance. This change is detected by the Wheatstone bridge, producing a voltage signal that the microcontroller 13 converts into a digital format to calculate torque. The microcontroller continuously monitors the torque, providing real-time feedback and initiating corrective actions if necessary.

[0085] Arotary encodercan be used to measure the angular displacement and rotational speed of the drive shaft 14. By combining this data with the motor’s current draw, the system can calculate the torque being applied.

[0086] The torque sensor data is continuously monitored by the microcontroller 13, which uses this information to control the motor’s operation. If the torque exceeds a predefined limit, the microcontroller can stop the motor to prevent damage to the bone or the fastener. Additionally, the system can perform automatic thread cleaning by reversing the motor’s direction for a specified number of rotations to clear debris from the threads.

[0087] The torque sensor 32 also enables the system to generate real-time torque curves, which are displayed on the user interface. These curves help the surgeon understand the progression of the fastener insertion and identify any anomalies, such as excessive torque indicating potential thread stripping or insufficient torque suggesting poor bone engagement.

[0088] Position control

[0089] For position-controlled fastener insertion, the screwdriver 1 may include a position sensor mounted to the motor shaft of the motor 10. An incremental encoder is sufficiently accurate for this application and can be used to control actuators such as brushed and brushless direct current motors. The proposed innovation is independent of the actuator type, making the choice of actuator dependent on the specific use and tool design.

[0090] Wireless communication

[0091] The surgical screwdriver is equipped with wireless communication capabilities through a wireless unit 133, allowing it to connect seamlessly with external devices to make up a system 100 (such as shown in). The external devices may be one or more of for example digital tablets 400, PCs or hospital information system terminals 600. The supported wireless technologies may include any useful technology such as Bluetooth for short-range communication, Wi-Fi for connecting to local networks and accessing internet-based services, cellular (4G / 5G) for broader connectivity, and NFC (Near Field Communication) for quick data exchange with compatible devices.

[0092] The system 100 includes a user-friendly interface accessible on external devices like tablets 400 and PCs / terminals 600 (such as shown in Figs. 7-9). This interface allows surgeons and medical staff to interact with the screwdriver in real-time. Key features of the interface include settings configuration, real-time monitoring, data visualization, and remote control. Users can set parameters such as rotational speed 505, torque limit values (TMAX) 506, and operational modes. The interface displays real-time data, including torque curves, insertion length status, and fastener specifications 533. Graphical representations of torque vs. insertion length help surgeons understand the progression of the fastener insertion and identify any anomalies. Surgeons can control the screwdriver remotely, adjusting settings and responding to alerts without needing to handle the device directly.

[0093] The system automates the registration of fastener data on the fastener(s) to be used, enhancing traceability and reducing manual entry errors. This may be achieved through optical scanners and / or cameras for reading barcodes, QR codes, AruCo codes, through text recognition of the serial numbers on fastener packaging or similar methods. Alternatively, or in addition, detection via NFC / RFID offers a compact solution unaffected by optical interference, such as vapor, but requires NFC / RFID tags to accompany the fastener packaging. In addition, manual entry via a keyboard or touchscreen interface may be available if needed. An example of a small form factor camera for registering product information on the fastener packaging is an Arducam Mini.

[0094] The system provides real-time feedback and alerts to the surgeon, ensuring optimal performance and safety. This includes continuous monitoring of torque to prevent over- tightening and thread stripping, calculation of the number of rotations needed to reach the desired insertion length with automatic stopping when the target is achieved, and automatic thread cleaning if high torque is detected.

[0095] The system can integrate with hospital information systems to streamline data management and enhance patient care. This includes automatic updating of patient records with details of the fasteners used, tracking of fastener usage and inventory levels to ensure timely restocking and reduce waste, and detailed logging of the surgical procedure for future reference and quality control.

[0096] As an example of workflow, during pre-surgery setup, the surgeon configures the screwdriver 1 settings on a tablet 400 or terminal 600, including torque limits and insertion length. Fastener data is registered using an optical scanner or NFC / RFID sensor. During surgery, the surgeon and / or assistants monitors real-time data on the tablet, adjusting settings as needed. The system provides alerts if torque limits are exceeded or if thread cleaning is required. Post- surgery, the system automatically updates the patient’s electronic record with details of the fasteners used and the insertion parameters. Inventory levels are adjusted based on the fasteners used.

[0097] This integration ensures that the surgical screwdriver system 100 not only is a powerful tool for surgeons but also a valuable component of the broader healthcare ecosystem, enhancing efficiency, accuracy, and patient safety.

[0098] Referring to, a schematic side view drawing of a surgical fastener 50 is illustrated. The surgical fastener is normally self-tapping and comprises a total length extending from the tip of the fastener to its distal head 51, a thread length, wherein the distance between the threads 52 is defined as the thread pitch, and a core diameter.

[0099] Surgical fasteners are typically categorized based on the type of bones they are designed for, primarily falling into two categories: cortex fasteners and cancellous fasteners.

[0100] Cortex Fastenersare fully threaded and specifically adapted for cortical bones, which constitute the denser outer layers of bones primarily serving to protect the internal cavity. Cortex fasteners feature a smaller thread pitch compared to cancellous fasteners, resulting in a greater number of threads per unit length. The ratio of the inner diameter to the outer diameter of cortex fasteners is lower. These fasteners are designed to achieve a stronger purchase within cortical bones.

[0101] Cancellous Fastenerscan be either fully or partially threaded and are adapted for cancellous bones, also known as spongy bones, which are softer than cortical bones. Cancellous bones are typically found at the ends of long bones, such as ribs, skull, and pelvic bones. Cancellous fasteners are generally longer than cortex fasteners and have a larger thread pitch. The threads of cancellous fasteners are deeper, and the ratio of the inner diameter to the outer diameter is higher.

[0102] The relationship between the fastener thread pitch, the number of rotations of the fastener, and the insertion length into a material can be expressed by the following equation:Insertion Length (LINS) = Fastener Thread pitch (PTH) × Number of Rotations

[0103] Given that the fastener thread pitch is the distance between the threads 52 of the fastener 50, each complete 360° rotation of the fastener results in an advancement into the material by a distance equal to the thread pitch.

[0104] The surgical fastener 50 may have a conical head 51 as shown inwherein the head essentially may lodge into the bone surface and be flush with the bone surface. The predefined insertion length (LINS) of the fastener 50 is then equal to the total length of the fastener.

[0105] Alternatively, the fastener may have a flat head, not allowing the head 51 to enter the bone tissue. These types of fasteners may be used to fixate a bone splint or brace on the outer surface of one or more bones in multiple positions. The predefined insertion length (LINS) of a flat headed fastener is then the length of the threaded and un-treaded part of the fastener without the head height, alternatively also minus the thickness of any splint or brace being attached between the bone tissue and the head.

[0106] It should be noted that it is common practice to predrill holes into bone tissues before inserting a self-tapping threaded fastener, which taps its own threads in the surrounding bone but not the entire hole itself. This due to bone, and especially cortical bone, being relative hard and might result in the fastener stripping its former threads, pulling off the head or rupturing. The diameter of the hole must be adapted to the core diameter and thread diameter of the threaded fastener, as well as type of bone the fastener is to be inserted in. However, the present invention is not limited to the practice of predrilled holes and will also function with self-tapping fasteners without predrilling, but with different operating parameters.

[0107] Referring to, an example of a femur bone 60 tissue part is illustrated in a cross-sectional view, comprising both cortical 61 and cancellous 62 bone. The figure includes exemplary torque curves established by the inventive system and projected onto the bone tissue part, following the fastener insertion length progression left to right in the bone tissue from one surface through different bone tissues in a section of the bone to the opposite side, according to one embodiment of the present invention. The torque curve is shown in more detail in, where the ideal torque curve 100 is depicted with a solid line.

[0108] As a fastener 50 proceeds from the left surface of the bone towards the opposing right side, passing through the middle section of the bone, certain characteristics of the curve are expected, as explained below with reference to

[0109] As the tip of the fastener 50 is pressed against the outer bone surface, the torque curve value 101 is near zero before the fastener grips into the bone tissue 61. Upon gripping, the torque increases rapidly to a temporary maximum 102, having surmounted the outer part of the cortical bone. As the insertion progresses, the torque may slightly drop before surpassing the inner wall of the cortical bone, which may result in a small secondary peak 103 due to somewhat increased hardness before the fastener enters the center region of cancellous bone. In this region, resistance is lower, and the torque sinks to a lower level 104 than for the cortical wall, but still higher than before insertion, as the fastener is still opposed by frictional forces from the new threads cut and tissue it progresses through. When entering the opposing cortical wall, the torque increases rapidly again, similar to the initial entry into the first cortical section. The total torque may be about the same as for the first cortical wall or higher due to the inherent friction of the bone tissues the fastener has already displaced and cut threads in. Two local peaks 105 and 106 (which may be similar to the former peaks 102 and 103) may be recorded before the torque drops 107 as the fastener reaches the outside tissue region on the other side of the bone. Unless insertion is halted, the torque will again increase rapidly as the head 51 of the screw enters into the bone tissue on the opposite cortical bone surface in case of a conical headed fastener 50 or is prevented from further insertion in case of a flat headed fastener as shown by a dotted line. Without an active torque control and torque limiting function, the torque will reach a maximum 108 risking damaging the cut threads. In case the available length of the fastener is shorter than the total bone thickness the torque will increase directly from the local peak 106.

[0110] By monitoring the torque of the screwdriver 1 in real-time and plotting the torque curve as shown in, the surgeon can interpret the curve during fastener insertion to understand what type of bone is being displaced by the fastener. A torque value of the curve in the first region between torque limits 201 and 202 will indicate the first cortical wall, a torque value below the first region’s lower limit 201 may indicate the passage through cancellous bone, and a torque value of the curve in the second region between limits 203 and 204 (which may be equal to 201 and 202) will indicate the second cortical wall.

[0111] The torque thresholds are critical parameters in the operation of the surgical screwdriver, ensuring precise control and preventing damage during fastener insertion. Below is a more detailed description of the torque thresholds and their roles:First minimum Torque Threshold (torque limit 201)This threshold indicates the point at which the fastener begins to engage with the bone tissue. It helps the system recognize when the fastener has started taping and cutting threads into the bone.When the torque reaches this first minimum threshold, the screwdriver and system start logging the number of rotations to calculate the fastener insertion displacement. This threshold ensures that the system only starts tracking the insertion once the fastener is properly engaged with the bone.First maximum Torque Threshold for first Bone Wall (torque Limit 202)This threshold is set to prevent excessive torque that could damage the bone threads or the fastener during the initial insertion phase through the first cortical bone wall.If the torque exceeds this first maximum threshold, the system stops the forward rotation and may initiate an automatic thread cleaning cycle. This involves reversing the fastener for a predefined number of reverse rotations to clear debris from the threads before resuming forward rotation.Second minimum Torque Threshold (torque Limit 203, may be equal or higher to torque Limit 201)Purpose: This second minimum Torque Threshold is used to detect when the fastener has passed through the first bone wall and entered the medullary (cancellous) bone tissue.Function: When the torque drops below this second minimum Torque Threshold, it indicates that the fastener is progressing through the softer cancellous bone. The system continues to log the number of rotations to track the insertion displacement through this region.Second maximum Torque Threshold for second Bone Wall (torque limit 204, may be higher or equal to torque limit 202)This second maximum Torque Threshold is set to prevent excessive torque during the final insertion phase through the second cortical bone wall.Similar to the first maximum Torque Threshold, if the torque exceeds this limit, the system stops the forward rotation and may perform the thread cleaning cycle. This ensures that the fastener can progress smoothly through the second bone wall without damaging the threads.

[0112] The benefits of having precise torque thresholds are that it:Prevents Damage: By setting specific torque limits, the system prevents excessive force that could damage the bone threads or the fastener;Ensures Precision: Continuous monitoring and adjustment based on torque thresholds ensure precise control over the fastener insertion process;Enhances Safety: Automatic thread cleaning and stopping mechanisms based on torque thresholds enhance the safety and reliability of the surgical procedure; andImproves Efficiency: The automated process reduces the need for manual intervention, saving time and reducing surgeon fatigue.

[0113] These torque thresholds are integral to the intelligent operation of the surgical screwdriver, ensuring that fasteners are inserted smoothly and securely into bone tissue.

[0114] By knowing the type of bone being treated, the surgeon can interpret the progression of the fastener and become aware of any anomalies, either in the bone tissue itself or in the navigation and direction of the fastener insertion relative to the bone being treated. For example, a continuous low torque or only slowly increasing torque may indicate a fastener displacing only cancellous bone, which could result from a fastener inserted into the bone surface at a wrong angle. Conversely, a continuous high torque within the first torque limit region 201 and 202 could indicate a much too low angle of insertion, where the fastener has managed to enter the cortical wall but at an angle different from perpendicular to the bone surface, or not entering the predrilled hole, causing the fastener to displace itself transversally or outside the hole within the cortical wall.

[0115] Inthe ideal torque curve is depicted in solid line with specific points indicating the torque values at various stages of fastener insertion, such as initial grip, progression through cortical bone, and entry into cancellous bone.

[0116] A dotted curve 300 is also shown in, representing an alternative scenario without torque control where the torque increases to a level 301, causing the fastener to shear the threads already made in the displaced bone. This results in a loss of grip and a sudden drop in torque to a level 302, approximately zero. In the example of, such an alternative progression is illustrated at the second cortical wall. Here, the fastener initially grips the cortical bone, but as friction and torque continue to increase, the threads cut in the already displaced bone, particularly those in the first cortical wall which are the strongest, are sheared and destroyed. This situation is highly undesirable, as the fastener will lack proper fastening to the bone and risk dislocation under low stress, which should be avoided.

[0117] By monitoring the torque during fastener insertion, an overload of the threads in the bone can be prevented. This can be achieved either by manually or automatically stopping the fastener rotation using the powered screwdriver, as will be described in the following sections.

[0118] THE SYSTEM

[0119] Referring to-9, these figures represent the system user interfaces for tool control and settings on external devices connected to the screwdriver 1, such as by Bluetooth, Wi-Fi, or other connectivity methods. The interface displayed may include settings such as for rotational direction, speed, torque limit, sensitivity, guide light, and voice command. It may also show information such as status indicators for connectivity, battery charge, tool temperature, and current fastener type. The external devices may include any suitable device or system, such as a tablet 400, a PC / laptop, or a terminal 600 connected to a server or mainframe.

[0120] illustrates an example of a system interface for remotely controlling the initial settings of the screwdriver 1 on a tablet 400 before use. The tablet interface may include status indications as shown in the top right corner, and similar information may also be available on any type of computer screen. These indications may include preferences 401 for the interface of the tablet or computer, a battery indicator for the interface device 402, sound control 403, Wi-Fi 404, and Bluetooth 405 connectivity of the interface device.

[0121] The interface may include a settings menu 500 accessible through a functional settings shortcut icon 501, presenting current statuses 502 of important settings and functional control icons 503 for adjusting the settings of the screwdriver 1 and monitoring the status of such settings, as shown inImportant basic screwdriver settings values shown, with switch or dial regulation, may comprise one or more of the following: rotational direction 504, rotational speed 505, a torque limit 506, sensitivity of the torque limit 507, guide light 508, and voice command 509. In the case of an algorithm for reversing rotation upon reaching a torque limit, the interface may include activation of such a function 510, a torque limit for activation of the reverse rotation algorithm 511 if set lower than the general torque limit 506, and a reverse ratio 512, i.e., the number of reverse rotations per forward rotations within the torque limit 511. All the data available provides the operator with the opportunity to check that all parameters are set correctly before the procedure.

[0122] The interface may also include status information about the screwdriver 1 for monitoring purposes, such as tool connectivity status 530 (Bluetooth, Wi-Fi, USB), battery charge status 531, tool temperature 532, and the current fastener type registered 533. Additional features may be included if the screwdriver has a forward-pointing camera integrated for better visibility of the surgery being performed. These features may include a direct video feed window 550, with an activation button or feed indicator 551, a zoom function to zoom in on close-ups 552 and zoom out 553, the possibility to expand 554 the video feed window, to record 555, or to take pictures 556 during the procedure.

[0123] Referring to, an exemplary display of input data and data monitoring according to one embodiment of the present invention is illustrated. The interface provides real-time information on the torque exerted, remaining fastener length, and insertion progress. It may also include a picture of the fastener and its specifications.

[0124] In this embodiment, the interface of the tablet 400 or terminal 600 is prepared for use with the screwdriver 1, presenting status data such as a picture of the fastener to be inserted 560 and additional data specifications 533 on the fastener, such as: Manufacturer, Product ID, Serial no., Material type, Length, Thread length, Pitch, etc. The interface also provides real-time information on the actual torque 561 exerted, which is shown as zero since the procedure has not started in this example. Additionally, a numeric indication of the remaining length 562 of the fastener is provided, showing the total length of the fastener before insertion begins, along with a progress bar 563 indicating the insertion status. An animated visualization 564 may also be derived, relating to the indications of uninserted remaining length 562 and inserted length 563.

[0125] illustrates the interface of the tablet 400 or terminal 600 during the insertion of a fastener with the screwdriver 1. The display may include real-time torque data logging 534, insertion progress, and a torque vs. insertion length graph 104, helping the surgeon monitor the procedure.

[0126] For the screwdriver to detect when the threads are engaged in the bone, a signal must be sent to the microcontroller at the point of engagement. This can be achieved eithermanually, by having the operator press a button, orautomatically, by using a torque sensor to detect an abrupt increase in torque.

[0127] During the procedure, real-time information on the actual torque 561 exerted is displayed, here for example, 2 Nm. The progress of the threaded fastener insertion is indicated by the numeric values of remaining length 562, here 10 mm and insertion length status 563, here 20 mm. Additionally, a real-time torque curve is plotted on a torque vs. insertion length graph 534. The set torque limit is indicated by a top line 202, and a lower region line 201 may indicate the expected lower torque region of cancellous bone after passing through cortical bone, marked by a local peak 104. A support line 535 may also indicate the progress of the insertion along the insertion progress axis.

[0128] Referring to, a system 100 according to one embodiment of the present invention is illustrated including the surgical screwdriver 1 connected to a tablet 400 and / or a PC / computer terminal 600, facilitating enhanced control and monitoring during surgical procedures. The screwdriver 1 may be connected to one or both of a tablet 400 and / or a computer terminal 600. An additional connection between a tablet 400 and a terminal 600 may further enhance the ease of procedure monitoring and control. The components in this embodiment constitute a system for fastener insertion, providing an intelligent surgical screwdriver system that employs automatic methods to assist (orthopedic) surgeons in bone fastener insertion.

[0129] The system enables the functionality of registering surgical fastener specifications, such as fastener dimensions and properties, as well as the serial number, even before the fastener is removed from its packaging. This automation of the registration process saves both time and money.

[0130] Based on the previously scanned product information, the length of the fastener, thread length, and thread pitch (PTH) are available. Using this information, the number of rotations required for fastener insertion is calculated. For example, during insertion, the screwdriver may automatically stop when approximately 95% of the fastener length is inserted. The final 5% may then be manually controlled by the surgeon, relying on tactile feedback. This approach saves time while maintaining the highest quality standards.

[0131] During fastener insertion, a safety control algorithm monitors the torque signal and stops insertion if excessive torque is detected. This feature helps prevent the tearing out of threads from cortical bone. Additionally, an algorithm for cleaning the threads may be activated, performing a predetermined number of reverse rotations to clean the threads before continuing. Counter rotations, i.e., counterclockwise rotation for right-hand threads, help to remove any debris or tissue compacted into the threads during fastener insertion. The process of alternating forward and reverse rotations upon detecting high torque limits may be repeated several times to clean the threads during the insertion process, but not too many to avoid wearing out the threads.

[0132] Such a system can also be realized by integrating a small form-factor microcontroller 13 into the body of the screwdriver 1. The microcontroller acts as the “brain” of the screwdriver and performs the following tasks:Registers the fastener product information from a scanning sensor.Wirelessly communicates the product information to a hospital system.Calculates the number of motor rotations required to insert 95% of the fastener length.

[0133] Referring to, the steps of initializing the screwdriver are illustrated in a flow diagram of an algorithm used by the system during an Initialization Mode according to one embodiment of the present invention. The diagram shows the steps for setting tool options, registering fastener information, and confirming settings before entering the operation mode.

[0134] Once the power for the screwdriver is turned on, it will establish communication with external devices, such as a tablet and / or workstation, and reach an initialization state (State 00).

[0135] The user may enter and set tool options through the graphical user interface (GUI), which are then confirmed (State 01). At this point, the user can either return to set more tool options (State 00) or proceed to register fastener information. After the fastener information has been entered, either by scanning a QR code, a NFC / RFID tag or manually through the GUI, the information is confirmed (State 02). The fastener information may be corrected or supplemented by continuing to enter settings (State 01). Alternatively, the user may proceed to confirm all settings (State 03) and bring the screwdriver into Operation Mode.

[0136] Hence, the initialization mode prepares the surgical screwdriver for operation by setting up necessary parameters and registering fastener information and involve the following steps:Power On and Communication Establishment (State 00):When the screwdriver is powered on, it establishes communication with external devices such as a tablet 400 or workstation terminal 600. This connection is typically made via wireless technologies like Bluetooth or Wi-Fi.Setting Tool Options (State 01):The user enters and sets various tool options through the graphical user interface (GUI) on the connected device 400 / 600. These options may include rotational direction, speed, torque limits, and other operational parameters.Once the settings are configured, the user confirms them. If additional settings are needed, the user can return to State 00 to adjust them.Registering Fastener Information (State 02):The user registers the fastener information, which can be done through various means such as scanning a QR code, barcode, NFC / RFID tag or manually entering the data via the GUI. This information includes the fastener’s length, thread pitch, and other relevant characteristics.The registered information is confirmed. If corrections or additional data are needed, the user can return to State 01.Confirming All Settings (State 03):After all settings and fastener information are confirmed, the system finalizes the initialization process and prepares to enter the operation mode.

[0137] Referring to, a flow diagram of an algorithm used during the Operation Mode of the screwdriver is illustrated according to one embodiment of the present invention.

[0138] The algorithms perform:Continuous monitoring of torque to ensure precise control and prevent damage;Automatic Thread Cleaning by reversing the screwdriver to clear debris when high torque is detected;Real-Time Feedback by logging rotations and torque data to track insertion progress; andSupport User Interaction enabling the user to control the screwdriver through a connected device, adjusting settings and responding to alerts.

[0139] This detailed algorithm ensures that the surgical screwdriver operates efficiently and effectively, providing surgeons with a reliable tool for precise and safe fastener insertion.

[0140] illustrates a flow diagram of an algorithm used during the Operation Mode of the screwdriver according to one embodiment of the present invention. The diagram shows the example states of the screwdriver and the options available to the user, as well as the automatic functions that occur as the screwdriver operates and progresses or halts the insertion of a screw. The operations illustrated inwill be explained in more detail below, with reference also to the torque curves inas examples.

[0141] After completing the initialization process, where the necessary and desired settings as described above are set, the screwdriver enters a standby or rest state (State 0). The screwdriver may also be returned to this state by predefined functions or commands 601, such as after a screw insertion operation has been finalized. A command for bringing the screwdriver to the standby state may be executed e.g. by pressing both the forward and reverse buttons on the screwdriver simultaneously. In the standby state, or earlier, the proper bits may be mounted to the screwdriver, and the screw to be used attached to the bits.

[0142] From the standby state, the screwdriver is started by pressing either the forward or reverse button on the screwdriver, causing the motor to start spinning in the forward or reverse direction correspondingly (State 1). If any of the buttons are released, the motor will stop spinning, and the screwdriver will return to standby (State 0).

[0143] By keeping the forward button pressed, the screw insertion into the bone tissue may commence. When the screw tip is pressed against bone tissue, an increase in torque will be registered, corresponding to curve segment 101. Once the screw starts threading into the bone wall, a minimum torque threshold 1, which may correspond to the first minimum torque limit 201, is reached, indicating that screw insertion in the first bone wall has commenced (State 2). Passing the torque threshold 1 also triggers the logging of the number of rotations of the screw to calculate screw insertion displacement. The screwdriver will rotate, and screw insertion will progress as long as the forward button remains pressed and the torque remains below a maximum torque, such as the first maximum torque limit 202.

[0144] If the torque exceeds a maximum torque value set for the first bone wall, such as first maximum torque limit 202, the screwdriver will stop forward rotation and enter a clean threads cycle to clean the threads (State II). The clean threads cycle may include the screwdriver rotating a predefined number Z of reverse rotations to pull out built-up debris from the threads, followed by resuming forward rotation again (State 2). The number of reverse rotations is registered, and the corresponding screw length is calculated and subtracted from the screw progress. If the bone is unexpectedly hard and / or debris is not sufficiently cleared, resulting in reaching the maximum torque again, the clean threads process cycle will be repeated, and the screwdriver may loop between these states (State 2 and State II). A maximum number of repetitions of the cycle may be defined to stop the screwdriver within a certain progression distance, to prevent damage to the threads. This may be achieved by a counter in the clean threads cycle which when reaching a maximum value Y making the screwdriver exit the current mode and go to the Rest mode.

[0145] If the torque during progression through the first bone wall drops below a second torque threshold 2, which may be the same as threshold 1, such as the first minimum torque limit 201, this indicates that the screw has passed the first bone wall and entered a section of medullar bone tissue (State 3), as shown by curve segment 104. The number of rotations X is continuously logged to calculate screw insertion progress.

[0146] The maximum torque value set for the medullar bone area may be the same as for the first bone wall, such as first maximum torque limit 202, or another preset value. If the maximum torque value is reached, the screwdriver will stop forward rotation and enter a clean threads cycle to clean the threads (State III), as described earlier.

[0147] Once the screw reaches the second bone wall, the torque will increase above a minimum torque threshold 3, which may correspond to the second minimum torque limit 203, indicating that screw insertion in the second bone wall has commenced (State 4). The logging of the number of rotations X of the screw continues to calculate screw insertion progression. The screwdriver will rotate, and screw insertion will progress as long as the forward button remains pressed and the torque remains below a maximum torque, such as the second maximum torque limit 204.

[0148] If the torque exceeds the maximum torque value set for the second bone wall, such as the second maximum torque limit 204, the screwdriver will stop forward rotation and enter a clean threads cycle to clean the threads (State IV), as described earlier.

[0149] Once the number of rotations X of the screw reaches the number of rotations corresponding to the predetermined total screw insertion length (LINS), the motor will stop and lock (State 5).

[0150] Hence, the operation mode governs the actual use of the screwdriver during the surgical procedure. The algorithm ensures precise control over fastener insertion, monitoring torque, and performing automatic thread cleaning if necessary, by comprising the following steps:Standby State (State 0):The screwdriver starts in a standby or rest state. The user can bring the screwdriver to this state by predefined functions or commands, such as pressing both the forward and reverse buttons simultaneously.Starting the Motor (State 1):From the standby state, the user starts the motor by pressing either the forward or reverse button. The motor begins spinning in the corresponding direction. If the button is released, the motor stops, and the screwdriver returns to standby.Fastener Insertion Begins (State 2):The fastener insertion begins when the forward button is pressed, and the fastener tip is pressed against the bone tissue. The system monitors the torque, and once the fastener starts threading into the bone, a minimum torque threshold (torque limit 201) is reached.The system logs the number of rotations to calculate the fastener insertion displacement. The screwdriver continues to rotate and insert the fastener as long as the forward button is pressed, and the torque remains below the maximum torque limit (torque limit 202).Thread Cleaning Cycle (State II):If the torque exceeds the maximum torque limit (torque limit 202), the system stops the forward rotation and initiates a thread cleaning cycle. This involves reversing the screwdriver for a predefined number of reverse rotations to clear debris from the threads and then resuming forward rotation.The number of reverse rotations Z is logged, and the corresponding fastener displacement length is subtracted from the insertion progress. If the torque limit is reached again, the cycle is repeated, looping between State 2 and State II. A maximum number of cycle repetitions Y may be defined to prevent damage to the threads monitored by a counter in the loop.Progression Through Bone Tissue (State 3):If the torque drops below a second torque threshold (torque limit 201), it indicates that the fastener has passed through the first bone wall and entered the medullary bone tissue. The system continues to log the number of rotations to track the insertion displacement.Second Bone Wall Insertion (State 4):When the fastener reaches the second bone wall, the torque increases above a third torque threshold (torque limit 203). The system continues to monitor the torque and log the rotations.If the torque exceeds the maximum torque limit for the second bone wall (torque limit 204), the system stops the forward rotation and performs another thread cleaning cycle (State IV).Completion of Insertion (State 5):Once the fastener reaches the predetermined total insertion length (LINS), the motor stops and locks, indicating the completion of the insertion process.

[0151] The primary purpose of the automatic thread cleaning process (State II) as described in step 4 above, is to prevent the buildup of debris in the fastener threads during insertion. This buildup can occur when the fastener displaces bone tissue, especially in harder bone areas like cortical bone. If not addressed, the debris can increase friction, leading to higher torque requirements and potentially damaging the bone threads or the fastener itself. The detailed parts of the process is as follows:Torque Monitoring: During fastener insertion, the system continuously monitors the torque applied by the screwdriver by using a torque sensor 32.Torque Threshold Detection: The system is programmed with predefined torque limits based on the type of bone and the characteristics of the fastener. When the torque exceeds these limits, it indicates that the fastener is encountering significant resistance, likely due to debris buildup in the threads.Automatic Reversal: Upon detecting high torque, the system automatically initiates a thread cleaning cycle. This involves reversing the direction of the screwdriver for a predefined number of reverse rotations and then resuming forward rotation. The reverse rotations help to back out any debris that has been compacted into the threads.Resumption of Forward Rotation: After the reverse rotations, the system resumes forward rotation to continue the fastener insertion. The number of reverse rotations is carefully calibrated to ensure effective cleaning without significantly retracting the fastener.Repeat if Necessary: If the torque limit is reached again after resuming forward rotation, the system can repeat the thread cleaning process. This ensures that the fastener can progress smoothly through the bone tissue without excessive resistance.

[0152] The algorithm is performed by the microcontroller that processes torque data and controls the motor’s direction based on detected torque levels. The torque sensors provide the real-time feedback to the microcontroller which uses the algorithms to determine when to initiate the thread cleaning process and how many reverse rotations are needed.

[0153] The automatic thread cleaning process prevents thread damage by cleaning the threads during insertion, reducing the risk of damaging the bone threads or the fastener, and ensuring a secure and stable fixation. It also reduces surgeon fatigue by eliminating the need for manual intervention, thereby lowering the physical and cognitive load on the surgeon. Additionally, it enhances precision through continuous monitoring and automatic adjustments, maintaining precise control over the fastener insertion process and improving surgical outcomes. Furthermore, the automated process is faster and more efficient than manual thread cleaning, helping to reduce overall surgery time.

[0154] In the preceding description, various aspects of the inventive screwdriver according to the invention, as well as its related system and method, have been described with reference to the illustrative embodiments. For purposes of explanation, specific numbers, systems, configurations and workflows were set forth in order to provide a thorough understanding of the invention and its workings. However, this description is not intended to be construed in a limiting sense. Various modifications and variations of the illustrative embodiments, as well as other embodiments of the invention which are apparent to persons skilled in the art to which the disclosed subject matter pertains, are deemed to lie within the scope of the present invention.

Claims

A handheld surgical electrically powered screwdriver (1) for fastening a threaded fastener (50) with a predefined insertion length (LINS) into bone tissue (61,62), wherein the screwdriver (1) comprises:a tool connector (4), configured to rotate a threaded fastener (50);a motor (10), configured to provide rotational power to the tool connector (4);a power supply (12), configured to provide power to the motor (10);a microcontroller (13), including:a memory (131) for storing characteristic data of the threaded fastener (50) to be inserted, wherein the characteristic data include the predefined insertion length (LINS) and a thread pitch (PTH) of the threaded fastener (50); andan integrated torque sensor (132) for directly measuring a torque applied to the threaded fastener (50) in real-time;a housing (2) at least partly housing the motor (10), the power supply (12) and the micro controller (13);whereinthe microcontroller (13) is configured for:monitoring a number of rotations X of the threaded fastener (50) into the bone tissue (61, 62) to calculate and register an insertion displacement of the threaded fastener (50) into the bone tissue (61,62);monitoring torque data collected from the integrated torque sensor (132) in real-time; andstopping the rotation of the tool connector (50) if:the insertion of the threaded fastener (50) reaches the predefined insertion length (LINS); orthe integrated torque sensor (132) registers a predefined torque limit value (TMAX).The surgical screwdriver (1) in accordance with claim 1, wherein the surgical screwdriver further comprises a transformer (121) for transforming a voltage from the power supply (12) to the motor and wherein the micro controller (13) comprises a motor controller (134) for controlling the voltage to the motor (10).The surgical screwdriver (1) in accordance with claim 1 or 2, wherein the surgical screwdriver further comprises a gear mechanism (11) configured to transmit power from the motor (10) to the tool connector (4).The surgical screwdriver (1) in accordance with claim 3, wherein the power supply (12) has an elongated shape with a length and a width, and wherein the motor (10) and gear mechanism (11) are positioned in parallel at least partially along the length of the power supply (12).The surgical screwdriver (1) in accordance with any one of the preceding claims, wherein the screwdriver (1) is configured such that:if the screwdriver is stopped due to reaching the predefined torque limit value (TMAX), the screwdriver (1) performs a cycle of automatically reversing the rotation of the threaded fastener a predefined number of reverse rotations Z corresponding to a reverse displacement length, thereby cleaning threads in the bone tissue, followed by resuming the initial forward rotation of the threaded fastener.The surgical screwdriver (1) in accordance with claim 5 wherein the cycle is repeated a maximum number of cycles Y if no further insertion displacement of the threaded fastener beyond a position where the cycle was initiated is registered by the micro controller.The surgical screwdriver (1) in accordance with any one of the preceding claims, wherein the micro controller (13) comprises a wireless communication device, such as Wifi, Bluetooth, Infrared, cellular, or NRF, configured to receive at least the characteristic data of the threaded fastener (50) from an external unit.The surgical screwdriver (1) in accordance with any one of the preceding claims, wherein the integrated torque sensor (132) comprises at least one of:a current sensor, measuring current drawn by the motor (10) to calculate a torque;a strain gauge, attached to a gear mechanism (14) forming part of the surgical screwdriver (1), the gear mechanism (14) being configured to transmit power from the motor to the tool connector (4); anda rotary encoder for measuring the angular displacement and rotational speed of the tool connector (4).The surgical screwdriver (1) in accordance with any one of the preceding claims, wherein the screwdriver comprises a user activated control system, in signal communication with the micro controller (13), the user activated control system being configured to at least set the tool connector (4) in rotation.The surgical screwdriver (1) in accordance with claim 9, wherein the user activated control system comprises at least one button (3) activated by pressure, and preferably at least two buttons (3) configured for opposite direction of rotation of the tool connector (4).A surgical system (100) comprising the surgical screwdriver (1) in accordance with any one of the preceding claims, wherein the system comprises an external control system (400, 600) in signal communication with the micro controller (13) for controlling and monitoring the operation of the surgical screwdriver.The surgical system in accordance with claim 11, further comprising a graphical user interface, wherein the external control system (400, 600) is configured to gain access to the characteristic data stored in the memory (13) and to display at least part of the characteristic data on the graphical user interface.A method for inserting surgical fasteners (50) in bone tissue, by using the surgical screwdriver (1) according to any of the claims 1-8 or the surgical system (100) according to claim 11 or 12, comprising the steps of:monitoring the insertion displacement;monitoring the torque data; andstopping the rotation of the tool connector if:the insertion of the threaded fastener (4) reaches the predefined insertion length (LINS); orthe integrated torque sensor (132) registers a predefined torque limit value (TMAX).The method in accordance with claim 13, wherein the surgical screwdriver (1) further comprises a user activated control system, in signal communication with the micro controller (13), the user activated control system comprises at least one button, (3) activated by pressure, wherein the method further comprises the step of exerting a pressure on the at least one button (3) to activate rotation of the tool connector.The method according to claim 13 or 14, when claim 13 is dependent of claim 12, wherein the method further comprises displaying at least one of:the insertion displacement; andthe torque data;on the graphical user interface in real-time.

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