75 results about "Pubic fracture" patented technology

The invention provides a pelvic fracture area discrimination method and device based on deep learning, a medium, a program product and a terminal, and aims to improve image quality by acquiring a pelvic area CT image and executing preprocessing operation. And carrying out fracture region discrimination on the preprocessed image to generate one or more fracture discrimination candidate regions. And extracting a vertical central axis of the CT image, and extracting a non-injury area opposite to the fracture area based on the axis. And performing bilateral feature evaluation on the fracture discrimination area and the corresponding non-injury area to generate a clear pelvic fracture area. The problem that subjective judgment and symmetry utilization are insufficient in the prior art is solved, and the accuracy and reliability of fracture detection are improved. The precision of fracture recognition is improved, and the misdiagnosis rate is reduced. In a complex background and a low-contrast environment, the detection effect of the pelvic fracture is obvious. And through comprehensive analysis of symmetry characteristics, the auxiliary ability of clinical decision making is enhanced.

A fracture reduction mechanism for minimally invasive pelvic fracture surgery, comprising a support assembly, a drive assembly, a self-rotating clamping assembly, and a healthy side fixation assembly, wherein the drive assembly comprises a synchronous rotation module (21), a first ball screw module (22), a second ball screw module (23), a third ball screw module (24), and an arc guide rail module (33); the mechanism forms a frame-like closed structure through connection with an operating table (1) via bedside rails (2) on both sides of the operating table (1), the support assembly and healthy side fixation assembly are slidably connected with the bedside rails (2). By manually adjusting the linear movement distances and fixed-axis rotation angles of the above mechanism, six degrees of freedom translation and rotation of the pelvic fracture block can be achieved. The mechanism features high rigidity and load-bearing capacity, good portability, simple assembly and operation, high motion precision, and its motion center is a virtual point in space, the position of which can be adjusted according to patient position and fracture type, providing convenience for surgery.

The invention discloses a flexible traction device for pelvic fracture reduction. The flexible traction device comprises a translation unit, a lifting unit, a rotation unit, a traction rope winding and unwinding unit, a traction rope, a tensioning unit, a traction force monitoring unit and a bone nail clamping unit. By means of specific arrangement of the units and cooperative arrangement of the units, the problems that traditional manual traction operation is unstable, traction force is insufficient and the like are solved, damage to soft tissue is reduced, the risk of postoperative complications is reduced, stable and accurate support is provided for large traction force needed by pelvic fracture reduction, and the operation efficiency is improved. And the traction effect and the stability of the traction device are greatly improved.

The invention relates to a remote control pelvic fracture reduction system, which comprises a man-machine interaction automatic control unit, more than two servo driving systems and more than two pelvic rotary push-pull devices, and the man-machine interaction automatic control unit interacts through a man-machine interaction interface. A reset path automatic planning strategy is formulated based on an artificial intelligence algorithm of a pelvis unlocking reset path, and then servo driving of a high-precision servo motor is provided by each servo driving system according to the reset path automatic planning strategy; then, the pelvic rotating push-pull devices connected with the pelvic rotating push-pull devices are driven to execute axial displacement push-pull reduction actions in respective directions on the pelvic fracture blocks of the patient, so that cooperative and consistent multi-degree-of-freedom space linkage of the pelvic fracture blocks of the patient is completed, and angular rotation and axial push-pull reduction on a plurality of two-dimensional planes under remote automatic control are realized; intelligent, precise and minimally invasive reduction of serious displacement pelvic fracture is achieved, the access threshold of pelvic fracture treatment is lowered, and meanwhile perspective radiation injuries to medical staff and patients are reduced.

The invention provides a pelvic fracture image segmentation method based on a dynamic convolution long-short term memory module, relates to the technical field of medical image segmentation, and solves the technical problem of low segmentation efficiency of a pelvic fracture CT image at present. The method comprises the following steps: extracting pelvic bones from pelvic CT scanning data by using a specified anatomical segmentation network; a fracture segmentation network comprising a dynamic convolution long-short-term memory module is used for carrying out image segmentation on bone fragments in each pelvic area in a pelvic skeleton, and in the image segmentation process, multi-scale context features are integrated through the dynamic convolution long-short-term memory module, and a space and channel dependency relationship is captured; feature fusion is completed in the processing layer by using a dynamic weight method, and finally key fracture fragments of a target skeleton in pelvis CT scanning data are obtained through an image segmentation process of a fracture segmentation network; the fracture segmentation network comprises an encoder, a decoder and a bottleneck layer, and the bottleneck layer comprises a dynamic convolution long-short time memory module.

This application discloses an external positioning and guiding device for pelvic fracture channel screws. This application achieves a first repositioning of the lesion location through a percutaneous positioning guide plate with multiple spaced positioning perforations and multiple first positioning tubes connected to the base body, each equipped with a positioning and guiding component. The first positioning tubes pass through corresponding positioning perforations, abutting against the patient's iliac bone, thus achieving a second repositioning of the lesion location. Multiple first positioning pins pass through corresponding first positioning tubes and connect to the patient's iliac bone, achieving stable connection and limitation of the base body based on dual positioning, preventing base body displacement. Finally, by connecting the positioning guide tubes to the base body and passing the channel screws through the positioning guide tubes, connecting the affected and healthy iliac bones, the channel screws are positioned and oriented.

The utility model relates to the technical field of turning-over assisting, and discloses a pelvic fracture external fixation patient turning-over assisting device which comprises a bed frame, a hollowed-out bed board is installed on the bed frame, a turbulent flow fan is installed on the hollowed-out bed board, an inclined board set is arranged in the hollowed-out bed board, and a limiting hole is longitudinally formed in the middle of the hollowed-out bed board. A rotating shaft is inserted into the limiting hole, an inclined plate group is mounted on the rotating shaft, and a motor is mounted on the outer wall of the bed frame. When a patient needs to be assisted in turning over, a motor drives a rotating shaft to rotate, the rotating shaft rotates to drive an inclined plate set to turn over, one side of the inclined plate set tilts up, and therefore the patient is assisted in turning over, and when the inclined plate set tilts, a turbulent flow fan below the inclined plate set on the side which is relatively tilted and lifted is started, and the patient is assisted in turning over. Therefore, air on the turning-over side of the patient is disturbed, the ventilation effect across the bedding is improved, and the phenomenon of pressure sores of the patient is relieved.

This invention relates to the field of fracture fixation technology, and more particularly to an inflatable pressure pelvic fracture fixator, comprising an L-shaped plate, an air pump fixedly connected to one side of the L-shaped plate, an air bladder fixedly connected to one side of the L-shaped plate, a rectangular groove formed on one side of the L-shaped plate, and a protrusion fixedly connected to the other side. A retaining strip is fixedly connected to the surface of the protrusion. When a patient with a pelvic fracture needs fixation, the fixator is moved from the patient's sides towards the patient's waist, allowing the L-shaped plate to extend below the patient's waist. The retaining strip on the surface of the protrusion engages with the retaining groove inside the rectangular groove, thus fixing the patient's waist. When the protrusion is inserted into the rectangular groove, a trapezoidal block is compressed into the groove. When the protrusion is fully engaged with the rectangular groove, the trapezoidal block extends out from the groove and penetrates the through groove under the elastic potential energy of the spring, thus fixing the protrusion inside the rectangular groove.

The application discloses a three-axis motion parallel reset mechanism for closed reset of a pelvic fracture, which comprises a sick side pelvic fracture reset robot and a healthy side fixing device, and the sick side pelvic fracture reset robot comprises a movable base, a three-axis moving device, a three-axis rotating device, a reset force detecting device and a sick side screw holding device. Through the above structure, six-degree-of-freedom translation and rotation of a fracture block can be realized, and the reset force change can be monitored in real time, thereby providing a guarantee for operation safety. The three-axis rotating device is connected in series through a U-shaped frame, has a smaller space occupation than a traditional ball pair, can be close to the upper surface of a human body during reset, has a short force arm and can provide a larger reset force. The robot has the advantages of compact structure, high precision, large load force, high flexibility, large working space, a spatial virtual point as a motion center, adjustable position according to a patient and a fracture type and convenient operation.

The present invention discloses a pelvic fracture fixation device, which relates to the field of medical device technology and includes: two symmetrically arranged fixed structures, each including a fixing frame, a first airbag, and a pressure regulating assembly, the first airbag being fixed to the fixing frame, the first airbags in the two fixed structures being arranged relative to each other, the pressure regulating assembly having an output end, the output end of the pressure regulating assembly being connected to the first airbag; two symmetrically arranged connecting structures between the two fixed structures, the two connecting structures being located at the two ends of the two fixed structures, the connecting structures including a connecting rope and a reeling assembly, the reeling assembly being arranged on the fixing frame of one of the fixed structures, the reeling assembly having an output end, one end of the connecting rope being connected to the output end of the reeling assembly, and the other end of the connecting rope being connected to the fixing frame of the other fixed structure. The advantage of the present invention is that it can adapt to the pelvic morphology of different patients, while providing a more secure fixation and avoiding problems such as displacement.

The invention discloses a pelvic fracture minimally invasive intramedullary fixing device in the field of medical instruments.The pelvic fracture minimally invasive intramedullary fixing device comprises a grip, a guide needle, a second rotary knob, a limiting assembly, a driving assembly and a cleaning assembly.The guide needle is arranged at the bottom of the grip and connected with the first rotary knob at the top of the grip, and a containing cavity is formed in the guide needle; a lifting plate is arranged in the containing cavity, a screw is connected to the bottom of the lifting plate, a second rotary knob is sleeved with the first rotary knob and fixed to the lifting plate, the first rotary knob is rotated to drive the guide needle to rotate, the position of the guide needle is adjusted, positioning is conducted, and when positioning is finished, the second rotary knob is rotated to drive the lifting plate and the screw to move downwards for fixing. The screw can be directly fixed after guiding and positioning, the guiding needle does not need to be pulled out, more convenience is achieved, and the problem that deviation is generated when the screw is fixed can be effectively solved.

The invention relates to the technical field of medical instruments, and discloses double knee fixing equipment for a pelvic fracture patient, which comprises a supporting shell, a first elastic piece is arranged in the supporting shell, a supporting frame is fixedly connected to the outer part of the supporting shell, a locking rod is arranged at one end of the supporting shell, and a second elastic piece is arranged at the other end of the supporting shell. The locking rod is arranged outside the first elastic piece, a self-adaptive mechanism is arranged inside the locking rod, the outer portion of the self-adaptive mechanism is arranged inside the supporting shell, the self-adaptive mechanism comprises a locking structure and an auxiliary assembly, and the outer portion of the locking structure is arranged inside the supporting shell and the locking rod. The first pressing block is pressed to drive the second elastic piece to be compressed, so that the effect that the device adapts to the body shape of a patient is achieved, the device can change according to the size of the lower limb posture of the patient, uniform and controllable constraint force is continuously provided, and fixing failure caused by constraint relaxation and displacement is fundamentally avoided.

The invention relates to a method for producing a template for a bone plate for treating a fracture of a bone of a human or animal, in particular for a bone plate for treating a pelvic fracture of a human. According to the invention, in order to produce the template in a patient-specific manner with high practical applicability, a digital data set of an image of bone fragments of the fracture is obtained using an imaging method, in particular an MRI or CT or X-ray method, wherein the method comprises the following steps: a) creating a digital, in particular virtual, three-dimensional bone model of the bone fracture fragments on the basis of the data set; b) determining a digital template design adapted to the bone model; c) producing, in particular 3D printing, the template on the basis of the determined template design. The invention also relates to a data processing device, to a system for producing the template, and to a computer program product.

The application discloses a kind of medical instrument technical field, a kind of planning method for pelvic fracture reduction surgical screw implantation path, comprising the following steps: the implantation number of retaining screw is calculated;The implantation position of retaining screw is calculated;The implantation direction of retaining screw is calculated.The input data of the application is the three-dimensional model of each broken bone of fracture pelvis and each fracture section point cloud that is reconstructed by preoperative CT of patient and spliced reduction completion, and the final task is to automatically generate the scheme of retaining screw implantation path in operation for the fracture condition of patient, including how many retaining screws are implanted, where retaining screw is implanted, in which direction screw is implanted and how deep is implanted.The application compared with existing conventional statistical model method, can guarantee the safety and optimal implantation effect of implantation path planning on personalized case;The retaining screw implantation planning path obtained by the application has stronger stability performance;Compared with traditional manual planning method, the planning time of single screw by the application is only about 5s, and the efficiency is improved by about 20 times.

A pelvis fracture reduction device, comprising a proximal end reduction mechanism, a distal end reduction mechanism and a connecting rod; the proximal end reduction mechanism comprises a first frame, a first positioning assembly mounted on the first frame for fixing the proximal end bone of the affected side; the distal end reduction mechanism comprises a second frame, an adjusting frame hinged with the second frame, a second positioning assembly mounted on the second frame for fixing the distal end bone of the affected side, a third positioning assembly arranged on the adjusting frame for fixing the distal end bone of the affected side; the first frame and the second frame are connected through the connecting rod. After the pelvis fracture and displacement occur, the distal end bone of the affected side and the proximal end bone of the affected side are reduced and closed through the external reduction device. The reduction precision is high, the recovery speed of the patient is fast, and the bone recovery effect is better. At the same time, the large range of scars left by incision of the fracture site is avoided.

The application discloses a kind of automatic segmentation method and automatic segmentation system of pelvic fracture image.The method comprises the following steps: obtaining pelvic fracture three-dimensional CT image, pre-processing the three-dimensional CT image, after processing, it is segmented by first convolutional neural network model, then it is registered to three-dimensional CT image, and the intensity information of non-bone tissue in registration image is shielded by Boolean operation, to obtain the three-dimensional CT image of bone tissue;The bone tissue three-dimensional CT image is segmented by second convolutional neural network model, to obtain all the main fragment images and secondary fragment group images of pelvis;The secondary fragment group image is solved and filtered by connected region, to obtain all the secondary fragment images of pelvis, and output all the main fragment images and secondary fragment images.The application realizes the full-automatic segmentation of pelvic fracture image, can accurately segment the main fragment image and secondary fragment image of each bone of pelvis, greatly simplifies the preoperative segmentation process in clinic, shortens the image processing duration.

Disclosed in the present invention is a tandem-type three-axis motion reduction robot for closed reduction of pelvic fracture, comprising an affected side pelvic fracture reduction robot and a healthy side fixing apparatus. The affected side pelvic fracture reduction robot comprises a movable base, a three-axis moving apparatus, a three-axis rotating apparatus, a reduction force detection apparatus, and an affected side screw holding apparatus. By means of the above structure, six-degree-of-freedom translation and rotation of a fracture block can be achieved, and the change of the reduction force is monitored in real time, thereby providing a guarantee for surgical safety. The three-axis rotating apparatus is connected in series by means of a U-shaped frame, occupies a smaller space than a traditional ball pair, can be close to the upper surface of a human body during reduction, and has a short force arm, such that a larger reduction force can be provided. The robot features compact structure, high precision, large loading force, high flexibility, and large working space; the motion center of the robot is a spatial virtual point, the position is adjustable according to patients and fracture types, and thus the operation is convenient.

The invention provides an automatic planning method and device for pelvic fracture virtual reduction based on template registration, and the method comprises the steps: carrying out the initial matching of a pelvic fracture block and a mirror image template of a pelvic affected side through a SAC-IA registration method based on the three-dimensional point cloud data of the pelvic fracture block and the three-dimensional point cloud data of the mirror image template of the pelvic affected side; obtaining an initial transformation matrix; updating the three-dimensional point cloud data of the pelvic fracture block based on the initial transformation matrix to obtain updated three-dimensional point cloud data of the pelvic fracture block; based on the updated three-dimensional point cloud data of the pelvic fracture block and the three-dimensional point cloud data of the mirror image template, performing final matching on the pelvic fracture block and the mirror image template by using an ICP registration method to obtain a final transformation matrix; and performing automatic virtual reduction on the three-dimensional model of the pelvic fracture block based on the initial transformation matrix and the final transformation matrix. According to the invention, the reset efficiency and the reset precision are improved.

Device for the approximate determination of the pelvic circumference of an injured person suspected of having an unstable pelvic fracture, with at least one measuring tape, characterized by that the measuring tape (9) has a zero mark (10) and several boundary marks (11 - 14) spaced apart from the zero mark (10), that different hip width ranges (15 - 17) are marked on the measuring tape (9) between the limit marks (11 - 14), and that this marking corresponds to a marking of hip circumference ranges that are specified in the product specifications of a particular pelvic sling.

1. The name of the design product: modular pelvis fixator. 2. The use of the design product: the design product is used as a medical device for the reduction and positioning of the deformed part of the pelvis in minimally invasive surgery for pelvic fractures, and for the treatment of pelvic fractures. 3. The design points of the design product: in shape. 4. The picture or photo that best indicates the design points: perspective view 1.

The utility model discloses a portable pelvic fracture fixing band which comprises a pelvic bone fixing band body, a fixing band body and a fixing band body, and latex is filled in the pelvic bone fixing band body. The hip bone fixing band is fixedly connected to the two sides of the pelvis fixing band, and the hip bone fixing band is filled with rubber, so that the hip bone fixing band has certain stretchability; the storage bag is fixedly connected to the outer side of the pelvis fixing band; the supporting bag is fixedly connected to the outer side of the hip bone fixing band; the supporting plate is stored on the inner side of the storage bag and can be pulled out of the storage bag, the supporting plate can be inserted into the supporting bag, and the supporting plate has a certain radian and can be attached to muscles on the two sides of the hip bone. Compared with the prior art, the fracture protection device has the advantage that the fracture protection device can support and protect the fracture area of the wounded person.

The utility model relates to the field of pelvic fracture fixation, in particular to a pelvic fracture fixing device for an emergency department, which can be shaped, can perform extrusion positioning in a targeted manner, and effectively solves the problems existing in fixation of a fixing band. Comprising a flexible fixing plate, a cross moldable metal framework is embedded in the fixing plate, the whole fixing plate is of a rectangular structure, a plurality of fixing bases with penetrating holes are arranged on the outer surfaces of the same sides of two short edges at intervals, a screw penetrates through the fixing bases opposite to one short edge and the other short edge, and a first nut is arranged at the penetrating-out end of the screw. And second nuts are respectively arranged on the screw rods on the inner sides of the fixed seats. The device is easy to operate, convenient to use and suitable for various patients.

This application discloses a method, system, computer device, and readable storage medium for pelvic fracture reduction, relating to the field of pelvic reduction technology, and solving the problem that orthopedic robots cannot reduce pelvic fractures in current treatments. The method includes: acquiring two-dimensional image information of the pelvis to be reduced; generating a two-dimensional pelvic model based on the two-dimensional image information using an image recognition algorithm; determining the parameter values ​​of deformity parameters based on the two-dimensional pelvic model, including pelvic angularity parameters, anteroposterior displacement parameters, lateral angularity parameters, lateral displacement parameters, axial angularity parameters, and axial displacement parameters; and calculating the set values ​​of six extension rods of the fracture reduction robot based on the parameter values ​​of the deformity parameters, so that the fracture reduction robot can reduce the pelvis of the target pelvis based on the set values ​​of the six extension rods.

The present invention provides a pelvic fracture anterior ring fixing screw, which relates to the technical field of orthopedic medical devices. The pelvic fracture anterior ring fixing screw comprises a screw seat tube, a screw and a limiting mechanism; the screw is arranged in the screw seat tube, and the front end of the screw extends out of the front port of the screw seat tube; the limiting mechanism is arranged in the cylinder cavity of the screw seat tube, and when the limiting mechanism presents a first state, the head of the screw is restricted in the screw seat tube, and when the limiting mechanism presents a second state, the screw can be separated from the screw seat tube as a whole. The pelvic fracture anterior ring fixing screw of the present invention realizes the combination and disassembly of the screw seat tube and the screw by setting a limiting mechanism, which facilitates the removal of the connecting rod and the screw seat tube while retaining the screw. On this basis, the present invention also provides an internal fixation device.

The utility model discloses a pelvic fracture conservative treatment device, and belongs to the field of medical instruments. Comprising two vertical plates, a distance adjusting structure and two clamping structures, the two vertical plates are arranged in parallel at an interval, the upper portions of the two vertical plates are connected through the distance adjusting structure, and the distance adjusting structure can adjust the distance between the two vertical plates; the lower portion of each vertical plate is provided with a clamping structure with an opening facing one side, and the openings of the clamping structures are oppositely arranged. The technical problems that when a patient is treated by a traditional pelvic fracture conservative treatment device, the patient cannot turn over and move, the comfort degree is low, and the traction effect is poor are solved.

The application relates to a simple pelvic fracture temporary fixing device, which comprises L-shaped supports, a sliding frame and a guide pipe, the two L-shaped supports are oppositely arranged; the sliding frame is movably installed between the two L-shaped supports, and the distance between the two L-shaped supports can be adjusted by changing the cooperation degree between the sliding frame and the L-shaped supports; the guide pipe is installed at the bottom of the L-shaped support and is arranged in parallel with the sliding frame. The application is simple in whole and convenient to operate, can effectively shorten the time length of the fixing process, guarantee the pelvic fixing effect, and avoid secondary injury to the patient.

The utility model relates to the technical field of medical equipment, in particular to pelvic fracture distraction equipment. Comprising an adjusting frame and an auxiliary mechanism, the auxiliary mechanism comprises a first angle arm, a second angle arm, a first telescopic arm, a second telescopic arm, a fixing frame, a connecting device and a locking device, and when equipment is assembled, the adjusting frame, the first angle arm, the second angle arm, the first telescopic arm and the second telescopic arm are combined and installed in advance; threaded steel nails are symmetrically driven into pelvic bones on the left side and the right side of a patient, the threaded steel nails are fixed through the fixing frame and the locking device, the fixing frame and the first telescopic arm and the second telescopic arm are installed in a matched mode through the connecting device, and finally the first angle arm and the second angle arm are slowly opened and locked through the locking device after being opened to a proper angle. Therefore, when the equipment is installed and used, convenient and fast installation can be achieved during installation, the clamping stability and the working efficiency can be improved during use, and operation and use are better facilitated.

The application belongs to the technical field of medical robots, and particularly discloses an active variable stiffness clamping device for pelvic fracture robot reduction, which comprises a matched contralateral adjustment support module and a healthy side fixing module, a pair of electric needle rod connecting piece modules connected with the contralateral adjustment support module are arranged on the contralateral adjustment support module; the healthy side fixing module comprises a healthy side bed clamp base, a healthy side support rod is arranged on the healthy side bed clamp base, a healthy side spherical hinge base is arranged on the healthy side support rod, and a pair of healthy side fixers in gap cooperation are arranged on the healthy side spherical hinge base; the clamping device is used for fixing the contralateral side and the healthy side of the pelvis, the healthy side fixing module fixes the part of the healthy side of the pelvis, the healthy side fixing module can be lifted and rotated, multi-directional adjustment and stable clamping of the damaged pelvis are realized.

The invention relates to an affected-side pelvic holding device of a pelvic fracture reduction robot. The affected-side pelvic holding device comprises a reduction force detection unit and an affected-side screw holding branched chain. The reset force detection unit is connected with the tail end of the robot through a six-dimensional force sensor, and vector parameters of reset force are monitored and fed back in real time. The three groups of affected side screw holding branched chains are distributed in an equilateral triangle shape, and the influence of screw deformation on reset precision is remarkably reduced through space coupling constraint among the branched chains. The affected side screw holding branch chain comprises a lockable universal spherical hinge assembly, a telescopic rod assembly and a rotary adjusting assembly, and has multiple degrees of freedom; the tail ends of the three branched chains can be quickly positioned and connected to screws on the affected side to cooperatively hold the pelvis on the affected side, and a rigid connection structure is formed after the three branched chains are locked; through the arrangement, the effects of real-time feedback of reset force, compact structure, high rigidity, large holding force and the like can be achieved, the device can adapt to any posture of an affected-side screw, the flexibility is high, operation is convenient and fast, and the safety and efficiency of affected-side pelvis holding operation are remarkably improved.

The utility model discloses a detachable cushion type pedestal pan, which belongs to the technical field of pedestal pans and is characterized by comprising a pan body, a seat cover structure is arranged at the top of the pan body, a comfortable component is arranged at the top of the seat cover structure, and a cover plate structure is arranged at the top of the comfortable component. The comfortable component comprises a hair-surface cushion arranged at the top of the seat cover structure, a hook-surface cushion is adhered to the top of the hair-surface cushion, and a soft sponge block is fixedly connected to the top of the hook-surface cushion. By arranging the comfortable component, the soft sponge block and comfortable breathable mesh cloth of the comfortable component can provide soft support and good breathability; the comfortable component is simple in structure and convenient to use, pain of a pelvic fracture patient when the patient uses the bedpan is effectively relieved, the comfort of the patient is improved, rehabilitation of the patient is facilitated, meanwhile, the hair surface pad and the hook surface pad are bonded, so that the comfortable component is easy to detach and clean, sanitation is kept, and the risk of cross infection is reduced.