INTRA-ARTICULAR NEEDLE PLACEMENT DEVICE AND METHOD FOR USING IT
Patent Information
- Authority / Receiving Office
- MX · MX
- Patent Type
- Patents
- Current Assignee / Owner
- AVANOS MEDICAL SALES LLC
- Filing Date
- 2022-06-17
- Publication Date
- 2026-06-12
Smart Images
Figure MX435007B0
Abstract
Description
INTRA-ARTICULAR NEEDLE PLACEMENT DEVICE AND METHOD FOR USING IT Background of the Invention A significant number of therapeutic intra-articular injections, particularly knee synovial cavity injections, are incorrectly placed outside the joint (Berkoff et al., 2012; Douglas, 2014; Hermans et al., 2011; Telikicherla and Kamath, 2016). Correct intra-articular or synovial cavity needle placement is unsurprisingly correlated with greater efficacy (Finnoff et al., 2015; Jones et al., 1993; Lundstrom et al., 2020; Sibbitt et al., 2009). Despite the benefits of precisely placed intra-articular injections, such as knee injections, insurers do not consider injection guidance technologies—ultrasound and fluoroscopy—which are medically necessary for the majority of patients receiving intra-articular injections. Consequently, few of these technologies and guide devices are in regular use for intra-articular knee injections.A second impediment to using ultrasound and fluoroscopy is staff training and equipment cost. Currently, there is a need for a device that can confirm proper intra-articular needle placement that is safe, effective, inexpensive, and intuitive, requiring minimal instruction before use. Furthermore, the device should be small and discreet, and importantly, easily integrated into current practices. One such device is described in U.S. Patent 8,608,665, which details a method for using a pressure-sensing device to confirm intra-articular needle placements. The method exploits a physiological property of the intra-articular cavity not shared by surrounding tissues: the subatmospheric (negative pressure) condition of the intra-articular space in non-effused knees. Intra-articular pressures are thought to play a role in condylar cartilage nutrition, meniscal load-bearing, and joint stability (Irvin, 2015). U.S. Patent 8,608,665 describes an algorithm that relies on detecting atmospheric pressure and the pressure within the intra-articular space of the knee.Specifically, the algorithm indicates joint penetration if the difference in atmospheric pressure and needle sensitivity is (i) beyond a defined negative threshold, (ii) sustained beyond a negative threshold for a defined period, and (iii) where the change in pressure over time is significantly steep and negative in its slope (e.g., ΔR / ΔT < -1.5). The literature suggests that the method described in U.S. patent 8,608,665 may fail to detect the intra-articular cavity in a large fraction of patients with osteoarthritis (OA) who present with knee pain. For example, (1) one report suggests that >90% of patients with OA who present with knee pain and radiographically diagnosed OA also have effusions (HUI et al., 2001); (2) effusions are correlated with a supra-atmospheric (positive pressure) intra-articular condition; and (3) effusions are frequently underdiagnosed, i.e., weak kappa classifications for intra- and interobserved clinical diagnoses of knee OA effusion (Hauzeur et al., 1999; Maricar et al., 2016).Therefore, a device with an algorithm solely dependent on sensitizing the subatmospheric condition of the intra-articular space lacks adequate sensitivity for the population it is intended to serve. Second, it is not widely recognized that not all positively compressed joints are effused. Positive pressure can also occur in response to flexion, application of pressure proximal but external to the joint, and load-bearing (such as standing). The methods in U.S. Patent 8,608,665 may not detect these positively compressed joints either. A joint effusion is the abnormal accumulation of fluid in or around a joint and is commonly caused by infection, injury, and arthritis. Excess joint fluid volume decreases range of motion (Strand et al., 1998; Wood et al., 1988) and increases intra-articular pressures (Caughey and Bywaters, 1963). Elevated intra-articular pressures, in turn, correlate with increased pain (Goddard and Gosling, 1988). While viscosupplementation injection is proposed to treat knee osteoarthritis (OA) pain in patients who have not responded adequately to conservative non-pharmacological therapy and simple analgesics (e.g., acetaminophen), the injection itself can cause additional pain if administered into an effused knee (by adding fluid to a joint that already has an abnormally high fluid level). Consequently, viscosupplementation prescribing guidelines state that effusions may be removed prior to viscosupplementation injection. As previously established, knee effusions are not commonly diagnosed during standard clinical examination (Hauzeur et al., 1999; Kane et al., 2003; Maricar et al., 2016). It may be advantageous to know the effusion status of a target joint prior to administering an intra-articular viscosupplementation injection. In response to the disadvantages highlighted above, the present invention revises the pressure sensitization method and reconfigures the device to respond to both subatmospheric and supra-atmospheric intra-articular conditions. Specifically, an algorithm is constructed (see Example 5) such that joint penetration is indicated if the difference between atmospheric and needle sensitized pressure is (i) beyond a defined negative or positive threshold; (ii) sustained beyond a threshold for a defined period; and (iii) where the change in pressure over time is significantly steep and either positive or negative in its slope. Intra-articular injections in poorly positioned knees are common and less effective than correctly placed intra-articular injections. Ultrasound and fluoroscopy are two joint injection guidance technologies that improve accuracy. As noted above, many payers do not consider these solutions medically necessary. The cost of implementation, which is not trivial, represents a barrier for many patients. Another barrier is the high cost of acquisition and training prior to implementation. Consequently, there is an opportunity for a low-cost solution that requires minimal training. Ideally, the solution could be integrated with current practices. The present invention describes a device and methods for confirming needle placement in the synovial cavity and for identifying joint effusion. The device exploits discernible pressure differences between extra-articular fluids and synovial cavities. These differences inform the physician when the needle connected to the device penetrates the synovial cavity. The present invention represents an improvement over previous pressure-sensing technology for confirming joint penetration, as both positive and negative pressures inform the user of needle placement in the synovial cavity before administering medication to the patient. If positive pressures indicate effusion, the physician can take appropriate action before administering medication. Furthermore, it is indicated that the device and methods of the present invention are also useful for veterinary procedures in animals such as horses, dogs, cats, cows, goats and sheep, as well as in human subjects. The design and construction of a laptop-connected device and a standalone self-powered device are provided. Studies of simulated tabletop joint articulation, cadaveric knee articulation, and animal synovial joint articulation using the laptop-connected device are also provided. Brief Description of the Invention The present invention relates to a device for detecting pressure differences encountered during injection into the synovial cavity. Synovial cavities exhibit a differential pressure reading in a normal steady state. Additionally, this differential pressure may be caused by a disease state in a subject, or it may have been induced by force or manipulation. The device of the invention comprises a power source (Panasonic CR1220 3V battery), a custom-stamped battery retainer, a power source isolation mechanism (non-conductive drag tab), a microprocessor (ST Microelectronics; part number STM8L101), two LEDs (Everlight Electronics), where one LED is blue (part number EAST 16084BB0) to indicate device “on” and the other LED is green (part number EAST0603GA0) to indicate penetration of the joint cavity, necessary capacitors and resistors, male and female luer-lock connections for specification ISO 594 and ISO 80369-7, male and female luer-lock connections connecting a hollow tube, within which a pressure transducer is mounted (Bosch BMP280 absolute barometric piezoresistive pressure sensor).The device is housed within a small plastic casing made of medical-grade plastic with known biocompatibility and sterility process compatibility. The measured absolute pressures are stored and analyzed by the microprocessor. Here, the pressure differentials and rates of change of supra- (positive) and subatmospheric (negative) pressure are calculated over time, and an algorithm is run to determine whether these pressure differentials and rates of change are indicative of synovial cavity penetration. The device also comprises one or more light-emitting diodes of different colors that illuminate when a needle connected to the device is exposed to the synovial cavity, such as that found within the intra-articular space of the knee. Human anatomical examples of synovial joints include: the cervical vertebrae (pivot joint); the ankle, elbow, and knee joints (hinge joints); the trapezium-metacarpal “thumb” joint (interphalangeal joints); the vertebral, carpal, metacarpal, tarsal, metatarsal, and zygapophyseal “facet” joints (plane joints); the radiocarpal, metacarpophalangeal, and metatarsophalangeal joints (condyloid joints); and the shoulder and hip joints (ball-and-socket joints). The device of the present invention confirms the placement of the needle in the synovial cavity for the purpose of administering medication to both humans and animals. Furthermore, the device of the present invention is useful in diagnosing joint effusions. It is an object of the present invention to record either positive (supra-atmospheric) or negative (sub-atmospheric) pressure when using the device and methods of the present invention. It is also an object of the invention to provide a method for using the device of the invention to provide confirmation of needle placement for synovial cavity-related applications and to record the resulting data in real time. An additional object of the invention is to optionally display the resulting data in real time to either a peripherally connected device, for example, a USB or Wi-Fi connected to a secondary source computer such as a laptop, tablet cloud base, or smartphone, or by means of the device itself. The availability of low-cost components allows for simple-to-use configurations which (i) mitigate the risks of nosocomial infection associated with multi-use devices, and (ii) allow for lower transfer costs, thereby facilitating greater adoption of the technology. An additional object of the invention is a method for diagnosing joint effusions, such as intra-articular knee effusions. In one embodiment of the device, the physician is informed by means of one or more LEDs, one or more LCDs, or a video output of pressure data over time connected to a laptop, as soon as positive and negative differential pressures are detected. It is then up to the physician to decide the appropriate course of action, i.e., to drain the effusion if the device indicates positive pressure, or to proceed with injection. An additional object of the invention is to provide methods for confirming correct needle placement in the synovial cavity and administering a medication. The positive pressure at the predetermined threshold is greater than 0.5 mmHg, with a range of 0.5 mmHg to approximately 200 mmHg. The negative pressure at the predetermined threshold is less than -0.5 mmHg, with a range of -0.5 mmHg to -100 mmHg. The predefined time period is at least 100 ms. In one method, the slope of the pressure change over time is positive and greater than 1 mmHg / second. In another method, the slope of the change over time is negative and less than -1 mmHg / second. In one modality, the predefined time period is at least 250 ms. Detailed Description of the Drawings Figure 1. Device dimensions (in millimeters). ινΐΛ / a / zuzz / uu 11 Figure 2. Device dimensions (in millimeters) of the sensor housing of the device connected to the laptop: side view (left panel) and rotated 90° around the vertical axis (right panel). Note the hollow tube connecting the luer-lock connections, and the circuit board-mounted piezoresistive pressure sensors positioned peripherally to the flow path. Figure 3. Diagram of the device connected to the laptop, showing the sensor housing, syringe, needle, Arduino controller, and a laptop running a custom data capture and visualization software application. Figure 4. The benchtop testing device consists of a partially filled and pressurized vial. The vial incorporates an airtight cap with a silicone septum to reseal the holes created by syringe needle punctures. Figure 5. Pressure data over time of the device connected to laptop from vial filled with inverted / pressurized liquid; vacuum-conditioned vial (top panel) and pressurized vial (bottom panel). Figure 6. Pressure data over time of the device connected to the laptop after intervening in the equine knee joint (top panel) and intervening in the equine fetlock joint (bottom panel). Figure 7. Pressure data over time of the device connected to the laptop after intervening in the goat carpal joint (top panel) and intervening in the goat knee joint (bottom panel). Figure 8. Graphical representation of the algorithm deployed in this invention. Figure 9. Graphical representation of the algorithm deployed in this invention, with the specific parameters for Example 5 defined. Note here ΔP = the difference in pressure differentials at time t2 and time t1, where time t2 = time t1 + 0.25 seconds, and ΔT = t2 - 11 or 0.25 seconds. Figure 10. Pressure data over time from the device connected to the laptop, obtained from ultrasound-guided intervention of the human lateral retropatellar joint (top panel) and fluoroscopically guided intervention of the human lateral parapatellar joint (bottom panel). The needle placement is also shown using ultrasound (inset image, top panel) and fluoroscopy (inset image, bottom panel). The dotted line indicates when the algorithm determines that the needle has penetrated the intra-articular cavity. Figure 11. Device dimensions (in millimeters) of the standalone device being built and tested: side view (left panel) and rotated 90° around the vertical axis (right panel). Figure 12. Independent alpha CAD drawings, with key components indicated. Figure 13. Illustration of negative pressure detection of the independent alpha prototype (approximately -4.3 mmHg reading on the manometer). Note that the blue LED turns off and the green LED turns on upon detection of negative pressure inside the vial. Figure 14. Discharge curve of the Panasonic lithium cell battery (CR1220) (solid line) at a consumption of 5 mA (dotted line - device power consumption rate) indicates that the device has sufficient power beyond the expected usage time of 10 minutes. ινΐΛ / a / zuzz / uu 11 Detailed Description of the Invention The target users of this device are licensed healthcare professionals who need to verify needle placement in the synovial cavity in either veterinary or human healthcare applications. One example of its use is confirming needle placement in the synovial cavity before administering a therapeutic agent or medication. Examples of medications include, but are not limited to, hyaluronic acid, corticosteroids, anesthetics, antibiotics, platelet-rich plasma (PRP), and mesenchymal germ cells (MSCs). Briefly, using sterile technique, the healthcare professional removes the device from its sterile packaging and attaches a pre-filled therapeutic syringe to one end and a sterile needle to the other. The operator then turns on the device (either via a pull tab or a button) and, observing the illuminated LED, proceeds with needle insertion without priming. Upon penetration of the intra-articular cavity (synovial cavity), the device's internal algorithm recognizes a pattern indicative of cavity penetration and illuminates a second LED, clearly signaling to the operator that the synovial cavity has been penetrated. The operator then injects a therapeutic agent or medication into the joint cavity and withdraws the needle. The second LED, once activated, remains illuminated continuously until the self-contained battery is depleted, thus ensuring the device remains in simple operation.This last point is extremely important to reduce the risk of nosocomial infection associated with multi-use medical device products. The device of the present invention is approximately 27 to 47 mm in length, 10 to 30 mm in width, and 10 to 30 mm in height (with the addition of luer-lock connections). The length is approximately 10 to 30 mm excluding the luer-lock connections. These dimensions are illustrated in Figure 1. Features common to all embodiments of the invention are a power source, a power source isolation mechanism, a microprocessor, male and female luer-lock connections to secure the syringe (constructed to ISO 594 and ISO 80369-7 specifications), a user communication mechanism, a channel (i) connecting the inside of the syringe to the needle lumen, and (ii) exposing the pressure transducer to pressures encountered by the needle. Unlike the device and method in U.S. Patent 8,608,665, the present device records both positive (supra-atmospheric) and negative (sub-atmospheric) joint pressures. The ability to detect supra-pressures allows for confirmation of needle placement in the synovial cavity of positively pressured synovial joints. Positive pressure can occur in response to joint flexion, the application of proximal but external pressure to the joint, and load-bearing, such as standing. Joint effusions also exhibit positive joint pressures. Therefore, the ability to detect both positive and negative joint pressures enables the present invention to more reliably identify synovial cavities under a broader range of circumstances.The positive joint pressure recorded and presented by the device can also be combined with other clinical features to support diagnoses of effusion. In another embodiment of the present invention, a translucent 3D stereolithographic housing (Formlabs FLGPCL04 resin) is printed. The housing contains male and female luer-lock connections that connect a hollow tube, positioned at opposite ends (the flow path). Inside the 3D-printed housing is a custom printed circuit board (PCB) on which several components are mounted: (i) a low-voltage microcontroller with 8 Kb of flash memory, 1.5 Kb of SRAM, and a 16 MHz processing speed (ST Microelectronics; part number STM8L101), and (ii) two LEDs for user communication (Everlight Electronics), where one LED is blue (part number EAST16084BB0) to indicate a device “on” and the other LED is green (part number EAST0603GA0) to indicate joint cavity penetration, and (iii) capacitors and resistors necessary for storing and regulating energy.A Bosch piezoresistive pressure sensor (part number BMP280) is mounted inside a hollow tube that bisects the flow path. This sensor is exposed to pressures within the needle lumen. Power is supplied by existing 3V lithium-manganese dioxide cell batteries such as Energizer (EBR1225) or Panasonic (CR1220). Example 1: Benchtop Equipment Device Test A translucent housing contains the hollow tube connecting the luer-lock fittings located at opposite ends (see Figure 2). A Bosch (BMP280) piezoresistive pressure sensor mounted on a circuit board and another ST (LPS22HB) pressure sensor are sealed within the housing. The pressure sensors are exposed to the flow path by another hollow bisection tube approximately 2 mm long. Associated electronics for USB power from a laptop and a communications control board are also sealed within the housing. Data is sent to a laptop running a custom application for real-time display of pressure and time data. After data collection, the data is saved to a comma-separated text file. A diagrammatic representation of the device connected to the laptop and associated components is illustrated in Figure 3.Benchtop testing simulates a fluid-filled, pressurized joint capsule as follows: A 10 mL glass vial is filled with 5 mL of water. A synthetic self-sealing septum cap is attached to the glass vial. A manometer (Extech model 406800) is connected to a 20-gauge needle via disposable medical-grade silicone tubing. The manometer is balanced to ambient pressure, and its needle is inserted through the membrane into the air portion of the vial. A second needle is inserted into the vial, and air is either added to pressurize the vial (e.g., to 5 mmHg) or removed to create a vacuum (e.g., to 5 mmHg). Both the manometer needle and the empty syringe needle are then removed. Following this preparation, the vial is inverted so that the fluid is now on top of the membrane.The pressure sensing device is assembled as shown in Figure 3, where a 20-gauge needle and a 5 mL syringe are attached. The device is then initialized by connecting it to the laptop's USB port and launching the data collection application. After initialization, the pressure sensors are automatically calibrated to ambient pressure. Finally, after initial data collection, the needle connected to the device is inserted into the liquid portion of the inverted, pre-pressurized vial. This setup is illustrated in Figure 4. The data collected from the benchtop equipment test are plotted as pressure versus time. As shown by the data represented in Figure 5, the laptop-connected device detects pressures that resemble known intra-articular pressures of non-weight-bearing, effused, and non-effused human knees. Non-effused knees have been reported to have pressures ranging approximately -5 to 10 mmHg (Alexander et al., 1996; Wood et al., 1988), and effused knees have been reported to have pressures ranging approximately 6 to 35 mmHg (Caughey and Bywaters, 1963). Note that the physiological pressures observed in the intra-articular joints are well within the specifications of the Bosch bmp280 pressure sensor's advertised pressure detection range. Regarding pressure sampling rate capabilities, consider that at relatively fast needle insertion speeds into the synovial cavity (2 seconds from superficial tissue puncture to synovial cavity penetration), and an approximate puncture depth of 25 to 38 mm, a pressure sampling rate setting of 25 ms will allow the Bosch bmp280 pressure sensor to measure pressures approximately every 0.3 to 0.5 mm of tissue penetration. This corresponds to approximately 80 pressure measurements before reaching the synovial cavity. Power consumption is very low at the 25 ms sampling rate, with an approximate amperage of 420 mA. The advertised specifications indicate absolute accuracy of + / - 0.75 mmHg, and relative accuracy + / - 0.09 mmHg. In short, the Bosch bmp280 pressure sensor is very sensitive and capable of detecting pressure differences per minute on time scales suitable for the purpose of this invention. Example 2: Equine Synovial Cavity Tests The laptop-connected device is used to probe the pressures of the medial femorotibial (knee) and metacarpophalangeal (fetlock) joint cavities of three horses. The primary objectives of the study are to acquire pressure data over time during joint intervention in a biological system, to observe the clinical use of the device, and finally, to collect user feedback. The horses are lightly sedated with xylazine and butorphanol. They are positioned fully on all four legs with their weight evenly distributed. Aseptic techniques are employed throughout the procedure, including sterile gloves and repeated applications of chlorhexidine and isopropanol to the injection site with rubbing. The device is assembled as shown in Figure 3, by attaching a 20-gauge, 3.5-inch (8.4 cm) needle and syringe. The needles are replaced after each joint intervention procedure.If it becomes apparent that fluid is entering the device's fluid path, the device is exchanged for an unused one. Pressure profile data measured with the device connected to the laptop are sent to the laptop and recorded. Ultrasound guidance is used throughout the procedure to confirm penetration of the joint cavity. To avoid contamination of the joints, the device is not used to aspirate or inject any fluid. Ten pressure profiles are collected using a device connected to a laptop, consisting of four fetlocks and six knees. All fetlocks and three of the knees give positive pressure readings. The remaining three knees produce negative pressure readings. Figure 6 illustrates negative and positive pressure profiles of an equine knee joint (top panel) and equine fetlock joint (bottom panel), as measured with the device connected to the laptop. Example 3: Intra-articular Goat Test The laptop-connected device was used to test intra-articular pressures in the radiocarpal and femorotibial joints of seven goats. The primary objectives of the study were to acquire pressure data over time during joint intervention in a biological system, to observe the clinical use of the device, and to collect user feedback. The animals were weighed and anesthetized, and endotracheal tubes were inserted to ensure airway maintenance. Blood pressure, end-tidal CO2, and pulse oximetry were used throughout the procedure to monitor the animal's condition and adjust the anesthesia. Each injection site was cleaned and covered under sterile conditions. Sterile technique was employed throughout the procedure. Approximately 1–3 mL of 0.5% Marcaine solution was injected.The needles are injected 25% subcutaneously proximal to each joint to avoid any potential pain. The device is assembled as shown in Figure 3, using sterile 21-gauge needles and syringes. The joints are then treated, and pressure profiles are recorded with the device connected to a laptop. The needles are replaced after each joint treatment. Data were successfully collected from 11 radiocarpal and 11 femorotibial joints. The radiocarpal and femorotibial joints exhibited both positive and negative pressure intervals. Figure 7 shows the negative pressure profiles obtained from interventions at the radiocarpal and goat's knee joints. Example 4: Cadaver Studies Two knee specimens (mid-tibia and mid-femur) were obtained from cadavers of two donors within 48 hours postmortem. One right knee was provided by a 63-year-old male donor, and one left knee by an 89-year-old female donor. Parameters affecting intra-articular pressures were controlled, including the needle procedure portal (lateral retropatellar during ultrasound or lateral parapatellar during fluoroscopy), guidance methodology for confirming joint cavity penetration (ultrasound or fluoroscopy), joint flexion angle (50 degrees from fully extended during ultrasound or acute flexion during fluoroscopy), pre-procedure flexion cycles (none), and patellar manipulation (none).The primary objectives of the study are to acquire pressure data over time during joint intervention in a human biological system, to observe clinical use of the device, and to collect user feedback. The female donor knee is placed in a supine position with 50° of flexion in a brace. A 1.5-inch (3.81 cm), 21-gauge needle is attached to the prototype device connected to the laptop, and the device is initialized. The joint cavity is then accessed via a lateral retropatellar procedure under injection guidance using a SonoSite M-Turbo ultrasound system and a SonoSite L25x 13-6 MHz linear array transducer. Pressure profiles collected by the device are saved to the laptop and analyzed. The pressure profile over time, shown in the top panel of Figure 10, is displayed several seconds before and after the needle penetrates the synovial cavity. The inset image shows the sonographic image captured when the needle penetrates the joint bursa.The needle tip is clearly visible in the anechoic space just below and adjacent to the highly echogenic patella. These sonographic anatomical landmarks are indicative of needle placement in the synovial cavity. The male donor knee is placed in a holder within limb C of the fluoroscopic imaging system (GE OEC 9900 Elite). The knee is allowed to flex naturally under its own weight to an acute flexion angle. A 21-gauge 1.5 needle is attached to the prototype device connected to the laptop and initialized by the device. The joint cavity is then accessed via a lateral parapatellar procedure under fluoroscopic guidance. Pressure profiles collected with the device are saved to the laptop and analyzed. The pressure profile over time is shown in the lower panel of Figure 10, several seconds before and after penetration of the synovial cavity by the needle connected to the device. The fluoroscopic image captured when the needle connected to the device penetrates the joint bursa is also shown in the inset photo.The needle tip is clearly visible in the space adjacent to the lateral femoral condyle, an area surrounded by a synovial cavity. Example 5: Algorithm Design Pressure data over time, based on Example 4, is analyzed, and an algorithm for determining joint cavity penetration is assembled and tested. The basis for this algorithm is as follows: 1) Establish a baseline atmospheric pressure before device initialization and set this to zero mmHg. 2) Define pressures found by the device above this baseline as positive or supra-atmospheric. 3) Define pressures found by the device that are below this baseline as negative or sub-atmospheric. ινΐΛ / a / zuzz / uu / / 4) During needle insertion, if the magnitude of the pressure measured on the device (whether supra- or subatmospheric pressure) is greater than 0.5 mmHg (P > [0.5 mmHg] for 250 milliseconds (ms)) or if the magnitude of the slope is greater than a predetermined amount, then 5) At each successive time point (condition -4 above is maintained), the pressure difference (ΔP) is calculated from the present time point to the previous time point 250 ms in the past, and 6) A value of 0.250 seconds is assigned to ΔT, the slope ΔR / ΔT is calculated in mmHg / seconds, and 7) if ΔΡ / ΔΤ > 1 mmHg / second, or if ΔΡ / ΔΤ < -1 mmHg / second, the LED, LCD, or other appropriate visual indication of joint penetration is triggered, and 8) Optionally, the current pressures found by the device are displayed, and / or 9) Optionally, a caution LED, LCD, or other suitable visual or audible indication of a potential effusion is indicated when the pressures encountered by the device are equal to or exceed 10 mmHg (P > 10 mmHg). A graphical representation of the algorithm is presented in Figure 8. The algorithm and parameters defined specifically for Example 5 are represented graphically in Figure 9. The algorithm correctly identifies synovial cavity penetration. The synovial cavity penetration signal is indicated by the dashed line in the upper and lower panels of Figure 10. In brief, the method of the invention first establishes a baseline atmospheric pressure and records a series of pressure readings at defined time intervals. Joint penetration is indicated if the difference between the reference atmospheric pressure and the pressure sensitized at the needle is (i) beyond a defined negative or positive threshold; (ii) sustained beyond the threshold for a minimum defined period; and (iii) where the pressure change corresponding to the time of change is equal to or exceeds a minimum slope criterion. Note that the slope can be either positive or negative. The method of administering a drug requires attaching a syringe and needle to the device and turning on the device before use. The user then monitors the visual indicators displayed on the device during a synovial injection procedure. Upon observing the signal of joint penetration, the user administers the drug. The method of the invention for supporting diagnoses of effusion involves the same method as before, accepting that, upon observation of a cautionary sign indicative of excessive pressure of the synovial joint, appropriate medical action is taken to release or further diagnose the effusion. Example 6: Construction and Testing of an Independent Device A translucent 3D stereolithographic housing (Formlabs FLGPCL04 resin) is designed. The housing contains male and female luer-lock connections that connect the hollow tube, positioned at opposite ends (see Figures 11 and 12). Inside the 3D-printed housing is a custom printed circuit board (PCB) on which several components are mounted: (i) a low-voltage microcontroller with 8 Kb of flash memory. 1.5 Kb of SRAM and 16 Mhz processing speed (ST Microelectronics; STM8L101), and (i) two LEDs for user communications (Everlight Electronics), where one LED is blue (EAST16084BB0) to indicate the device is “on” and the other LED is green (EAST0603GA0) to indicate joint cavity penetration, and (iii) capacitors and resistors required to store and regulate power.Mounted inside a hollow tube that bisects the flow path is the piezoresistive pressure sensor (Bosch; BMP280). As shown in the right panel of Figure 12, this short hollow tube is positioned below the PCB and the microcontroller. Its function is to express the pressure sensor to the pressures detected by the needle. Note that power is supplied by existing 3V lithium manganese dioxide cell batteries such as the Energizer (EBR1225) or Panasonic (CR1220). Using the benchtop test apparatus described in Example 1, the device is subjected to pressures > 0.5 mmHg in magnitude. As illustrated in Figure 13, the blue LED illuminates upon energizing the device; then, after exposing the needle to vial pressures > 0.5 mmHg in magnitude, the blue LED turns off and the green “synovial penetration” LED illuminates, as if in expectation. The Bosch pressure sensor, microcontroller, and LEDs are collectively not expected to draw more than 5 mA. As shown in Figure 14, the 1220 lithium cell provides adequate power for more than 30 minutes. Note that the device is expected to be used within 10 minutes of being powered on. A flashing mode after 10 minutes of operation can be implemented to alert the user that the device is beyond its intended operating timeframe. Preliminary feedback indicates that the device is of a size and weight that will not interfere with knee joint injections. Second, the brightness and color of the current LED are easily discernible from all angles. The foregoing examples are provided as illustrative of the device and methods of the present invention and are not limiting thereof. Literature Alexander, C., Caughey, D., Withy, S., Van Puymbroeck, E., and Muñoz, D. (1996). Relation between flexión angle and intraarticular pressure during active and passive movement of the normal knee. J Rheumatol 23, 889-895. Berkoff, D.J., Miller, L.E., and Block, J.E. (2012). Clinical utility of ultrasound guidance for intraarticular knee injections: a review. Clin Interv Aging 7, 89-95. Caughey, D.E., and Bywaters, E.G. (1963). Joint fluid pressure in chronic knee effusions. Ann. Rheum. Dis. 22, 106-109. Douglas, R.J. (2014). Aspiration and injection of the knee joint: approach portal. Knee Surg Relat Res 26, 1-6. Finnoff, J.T., Hall, M.M., Adams, E., Berkoff, D., Concoff, A.L., Dexter, W., and Smith, J. (2015). American Medical Society for Sports Medicine (AMSSM) position statement: interventional musculoskeletal ultrasound in sports medicine. Br J Sports Med 49, 145-150. ινΐΛ / a / zuzz / uu 11 Goddard, N., and Gosling, P. (1988). Intra-articular fluid pressure and pain in osteoarthritis of the hip. The Journal of Bone and Joint Surgery. British Volume 70-B, 52-55. Hauzeur, J.P., Mathy, L., and De Maertelaer, V. (1999). Comparison between clinical evaluation and ultrasonography in detecting hydrarthrosis of the knee. J. Rheumatol. 26, 2681-2683. Hermans, J., Bierma-Zeinstra, S.M.A., Bos, P.K., Verhaar, J.A.N., and Reijman, M. (2011). The most accurate approach for intra-articular needle placement in the knee joint: a systematic review. Semin Arthritis Rheum 41, 106-115. Hill, C.L., Gale, D.G., Chaisson, C.E., Skinner, K., Kazis, L, Gale, M.E., and Felson, D.T. (2001). Knee effusions, popliteal cysts, and synovial thickening: association with knee pain in osteoarthritis. J Rheumatol 28, 1330-1337. Irvin, W.O. (2015). Concepts of Etiologies and Effects of Normal Human Knee Pressure Variations. Anat Physiol 5, 172. Jones, A., Regan, M., Ledingham, J., Pattrick, M., Manhire, A., and Doherty, M. (1993). Importance of placement of intra-articular steroid injections. BMJ 307, 1329-1330. Kane, D., Balint, P.V., and Sturrock, R.D. (2003). Ultrasonography is superior to clinical examination in the detection and localization of knee joint effusion in rheumatoid arthritis. The Journal of Rheumatology 30, 966-971. Lundstrom, Z.T., Sytsma, T.T., and Greenlund, L.S. (2020). Rethinking Viscosupplementation: Ultrasound- Versus Landmark-Guided Injection for Knee Osteoarthritis. Journal of Ultrasound in Medicine 39, 113-117. Mancar, N., Callaghan, M.J., Parkes, M.J., Felson, D.T., and O’Neill, T.W. (2016). Clinical assessment of effusion in knee osteoarthritis-A systematic review. Semin Arthritis Rheum 45, 556-563. Sibbitt, W.L.J., Peisajovich, A., Michael, A.A., Park, K.S., Sibbitt, R.R., Band, P.A., and Bankhurst, A.D. (2009). Does sonographic needle guidance affect the clinical outcome of intraarticular injections? J Rheumatol 36, 1892-1902. Strand, E., Martin, G.S., Crawford, M.P., Kamerling, S.G., and Burba, D.J. (1998). Intra-articular pressure, elastance and range of motion in healthy and injured racehorse metacarpophalangeal joints. Equine Veterinary Journal 30, 520-527. Telikicherla, M., and Kamath, S.U. (2016). Accuracy of Needle Placement into the Intra-Articular Space of the Knee in Osteoarthritis Patients for Viscosupplementation. J Clin Diagn Res 10, RC15-RC17. Wood, L., Ferrell, W.R., and Baxendale, R.H. (1988). Pressures in normal and acutely distended human knee joints and effects on quadriceps maximal voluntary contractions. Q J Exp Physiol 73, 305-314.
Claims
1. A device for synovial cavity injections, the device comprising: a. a power source; b. a power source isolation mechanism; c. a pressure transducer; d. a microprocessor; e. male and female luer-lock connections; and f. a pathway connecting a syringe to a needle; wherein pressure changes are measured, recorded, and analyzed; and wherein the pressure changes are either supra-atmospheric (positive) or sub-atmospheric (negative).
2. The device according to claim 1, further comprising: one or more light-emitting diodes of different colors that illuminate when a needle connected to the device is exposed to the synovial cavity.
3. The device according to claim 1, wherein the device has dimensions of approximately 27 to approximately 47 mm in length, approximately 10 to approximately 30 mm in height, and approximately 10 to approximately 30 mm in width.
4. The device according to claim 3, the device further comprising: an element for reading and sharing real-time pressure readings.
5. The device according to claim 4, wherein the device is used in a synovial cavity of a human being.
6. The device according to claim 5, wherein the synovial cavity is located within the knee, hip, shoulder or spinal cord.
7. The device according to claim 6, wherein the synovial cavity is within the knee.
8. The device according to claim 7, wherein the measured pressure changes are atmospheric pressure, biological tissue pressure, and biological cavity pressure measurements are obtained over time.
9. The device according to claim 8, wherein the measured pressure changes are biological cavity pressures over time.
10. The device according to claim 3, wherein the power source is a lithium-manganese dioxide cell battery.
11. The device according to claim 3, wherein the power source isolation mechanism is a non-conductive drag tab.
12. The device according to claim 3, wherein the pressure transducer is a piezoresistor pressure sensor.
13. The device according to claim 3, wherein the microprocessor is a low-voltage microcontroller with flash memory, static random access memory and processor.
14. A method for administering a drug to a subject in an intra-articular cavity, using a pressure-sensing device, the method comprising: a. measuring and recording atmospheric pressure upon initialization of the device to establish baseline pressure; b. measuring and recording pressures at predefined time intervals; c. determining whether the pressure exceeds predefined thresholds for a predetermined time; and upon satisfaction of this condition d. calculating the change in pressure over the change in slope over time between two time points; and e. if the magnitude of the slope is greater than a predefined minimum, indicating that the needle has been placed within the intra-articular cavity; and f. injecting the drug into the intra-articular cavity.
15. The method according to claim 14, wherein the subject is an animal.
16. The method according to claim 15, wherein the subject animal is a horse, dog, cat, goat, sheep or cow.
17. The method according to claim 14, wherein the subject is a human being.
18. The method according to claim 17, wherein the intra-articular cavity is the hip, shoulder, spinal cord, or knee.
19. The method according to claim 18, wherein the intra-articular activity is the synovial cavity of the knee.
20. The method according to claim 14, wherein the predefined threshold is positive and greater than 0.5 mmHg.
21. The method according to claim 14, wherein the predefined threshold is negative and less than 0.5 mmHg negative.
22. The method according to claim 14, wherein the predefined time period is at least 100 ms.
23. The method according to claim 14, wherein the slope of pressure change over time is positive and greater than 1 mmHg / second.
24. The method according to claim 14, wherein the slope of pressure change over time is negative and less than -1 mmHg / second.
25. The method according to claim 14, wherein the predefined time period is at least 250 ms.
26. The method according to claim 14, wherein the drug is hyaluronic acid, corticosteroid, anesthetic, antibiotic, platelet-rich plasma (PRP), and mesenchymal germ cells (MSCs).
27. The method according to claim 14, wherein the medicament is hyaluronic acid. MA / a / ¿U¿¿ / UU 11 uz 28. A method for diagnosing effusion in a synovial joint, the method comprising: a. measuring and recording atmospheric pressure upon initialization of the device to establish baseline pressure; b. measuring and recording pressures at predefined time intervals; c. determining whether the pressure exceeds a first predefined threshold for a predefined period of time; and upon satisfaction of this condition, d. calculating the change in pressure over the change in time slope between two time points; and e. if the magnitude of the change is greater than a predefined minimum, reporting that the needle has been placed within the intra-articular cavity; and f. if a second predefined pressure threshold is exceeded, reporting that an effusion is present; and g. removing the effusion.
29. The method according to claim 27, wherein the first predefined pressure threshold is positive and greater than 0.5 mmHg.
30. The method according to claim 27, wherein the predefined time period is at least 100 ms.
31. The method according to claim 27, wherein the slope of the pressure change over time is positive and greater than 1 mmHg / second.
32. The method according to claim 27, wherein the second predefined pressure threshold is positive and greater than 10 mmHg.
33. The method according to claim 27, wherein the predefined time period is at least 250 ms.
34. A device for detecting pressure differences encountered within a body cavity during injections, the device comprising: a. a power source; b. a power source isolation mechanism; c. a pressure transducer; d. a microprocessor; e. male and female luer-lock connections; and f. a pathway connecting a syringe to a needle; wherein pressure changes are measured, recorded, and analyzed; and wherein the pressure changes are either supra-atmospheric (positive) or subatmospheric (negative).