81 results about "Pubic fracture" patented technology

Accurate pelvic fracture detection is accomplished with automated X-ray and Computed Tomography (CT) images for diagnosis and recommended therapy. The system combines computational methods to process images from two different modalities, using Active Shape Model (ASM), spline interpolation, active contours, and wavelet transform. By processing both X-ray and CT images, features which may be visible under one modality and not under the other are extracted and validates and confirms information visible in both. The X-ray component uses hierarchical approach based on directed Hough Transform to detect pelvic structures, removing the need for manual initialization. The X-ray component uses cubic spline interpolation to regulate ASM deformation during X-ray image segmentation. Key regions of the pelvis are first segmented and identified, allowing detection methods to be specialized to each structure using anatomical knowledge. The CT processing component is able to distinguish bone from other non-bone objects with similar visual characteristics, such a blood and contrast fluid, permitting detection and quantification of soft tissue hemorrhage. The CT processing component draws attention to slices where irregularities are detected, reducing the time to fully examine a pelvic CT scan. The quantitative measurement of bone displacement and hemorrhage area are used as input for a trauma decision-support system, along with physiological signals, injury details and demographic information.

A hip and pelvic splint system is designed to immobilize both the pelvic region and lower extremities of a patient suffering from a hip or pelvic fracture. This allows ready transport of the patient with little or no pain or additional injury caused by shifting of the hip or pelvis. The device consists of a foam leg insert that is first placed between the legs of a patient to help stabilize the patient's lower extremities. A flexible splint component is then slid beneath the patient's lets and hips. The splint component is then closed over the patient and tightened with straps. The lower edge of splint component is secured snuggly about the legs in the vicinity of the patient's knees so that the foam leg insert can immobilize the legs. The upper edge of the splint is secured snuggly about the upper abdomen, thereby immobilizing the pelvis. Hand holds on the device allow paramedics to lift the patient without distorting the fracture.

The invention discloses a pelvis CT three-dimensional reconstruction image postprocessing method based on a coordinate system and belongs to the medical image processing field. The method comprises the following steps of 101) collecting patient pelvis CT data; collecting pre-operation pelvis two-dimensional CT case data of a patient; 102) establishing a three-dimensional case model; using the case data, through three-dimensional reconstruction, acquiring a three-dimensional pelvis model of a case; 103) establishing the coordinate system in the three-dimensional pelvis model of the case; 104) acquiring a distance shift and a rotation shift of a pelvic fracture; and establishing a mathematic model in the coordinate system in the step 103), and accurately calculating distance shifts and rotation shifts of a fracture portion projected on X, Y and Z axes. By using the method, an orthopedist can conveniently, visually and accurately know a shift mode and a degree of the pelvis fracture of the patient and can accurately guide intraoperative reset for the patient.

The invention discloses a combined tool for percutaneous screw setting for minimally invasive pelvic fracture and belongs to the field of medical instruments. The combined tool comprises a casing (1), a straight-head probe (5) and a bent-head probe (6), the right end of the bent-head probe (6) is a flat elbow pushing end (601), the front end of the elbow pushing end (601) bends towards the flat side, the right end of the straight-head probe (5) is a flat straight-head pushing end (501) which is straight, and the right end of the casing (1) is sharp to form a sharp end (2). The casing (1) can be positioned accurately on a smooth bone inclined plane of a pelvis by the aid of the sharp end (2), drill holes can be fine adjusted as required to select the optimum screw setting position, and when the straight-head probe (5) deviates from a preset track and is blocked by cortical bones or pierce the cortical bones carelessly, the bent-head probe (6) is used for preventing a pushing end from falling into an original screw path. The combined tool has the advantages that the success rate of operations is high, the structure is simple, the operation is convenient, and the like.

A pelvic trauma device for emergency treatment of pelvic fracture includes two parallel elongated straps or belts that are connected, but are adjusted independently of each other. The two parallel belts include a lower belt and an upper belt. The two parallel belts are independently tensioned to provide: 1) pelvic fracture stabilization (lower belt); and 2) compression over the sacrum and anterior abdomen (upper belt).

An apparatus for stabilization of pelvic fractures comprising a stationary pad member, an adjustable pad member, and two trochanter pads. The stationary pas member comprises a cross-member with a rack gear. The adjustable pad assembly is configured to slide laterally on the cross-member so that the distance between the first and second trochanter pads is adjustable. The invention further comprises a torque release clutch that is configured to cause the retaining pawl gear tooth to disengage from the rack gear teeth when a certain force is applied to the torque release clutch.

The invention provides an inflation-reduction fixation band for first aid of pelvic fracture, which is characterized in that the fixation band comprises a pelvis inflation-pressurization fixing device, an inflation pipe and an inflation device; the pelvis inflation-pressurization fixing device comprises a strip-shaped gas chamber, a strip-shaped elastic fabric connected with the strip-shaped gas chamber and Velcro positioned at two ends of the strip-shaped elastic fabric; the middle part of the pelvis inflation-pressurization fixing device is provided with a rear support which supports pelvis and consists of at least two hard ribs; two sides of the rear support are provided with lifting handles; an elastic perineum pocket is arranged below the rear support under the pelvis inflation-pressurization fixing device; and the elastic perineum pocket is provided with an convenient opening and fastening Velcro. Compared with the prior art, the fixation band has the advantages that the fixation band reduces complications or secondary injury, is not easy to cause lower-limb fascial compartment syndrome or severe hypotension, does not interfere with evaluation of lower-limb situation and vessel treatment, and can play a role in effectively fixing and pressurizing for hemostasis during first aid for the wounded.

A minimally invasive intramedullary fixation device for pelvic fractures belongs to the technical field of orthopedic medical devices and is used for intramedullary reduction and fixation of pelvic fractures. The technical plan is: design the pelvic intramedullary tunnel in advance under the three-dimensional reconstruction of pelvic CT, make the guide wire and guide sleeve according to the curvature of the pelvic intramedullary tunnel, and use a soft drill to drill under the guidance of the pre-bent guide wire and C-arm fluoroscopy. Out of the pelvic intramedullary tunnel, put the arc-shaped intramedullary nail into the pelvic intramedullary tunnel along the guide wire, and fix the screws to securely connect the arc-shaped intramedullary nail to the pelvis. intramedullary nail. The pelvic intramedullary fixation adopted in the present invention is an innovation in the pelvic fracture fixation operation. This intramedullary fixation device and method can realize the perfect reduction and fixation of the pelvic ring and acetabular fractures with the cooperation of direct vision and C-arm irradiation. It is convenient and firmly fixed, which greatly shortens the operation time and recovery time, improves the treatment effect, and reduces the pain of the patient.

The invention relates to a pelvic internal fixation unit, which is composed of at least two pelvic internal fixation screws, a supporting rod and at least two fastening nuts, wherein the pelvic internal fixation screw is composed of a fully-threaded screw rod and a U-shaped tube sleeve. The invention further provides the application of the pelvic internal fixation unit. The pelvic internal fixation unit has the advantages that: the operation flows of traditional internal fixation of pelvic fracture and corrective osteotomy are changed so that the two surgical operations are simper in operations; a screw-rod fixation system is used, and the supporting rod can be bent randomly, thereby widening the applicable scope; the supporting rod comes into no direct contact with pelvis, which applies no influence on blood supply at the facture site and at pelvis below the internal fixation unit, therefore, bone union is quickened; the system adopts angle fixation and has good fixation effect, thereby avoiding the possibility of pulling out or loosening the screws; and minimally invasive operation can be realized through subcutaneous tunnel, thereby not only leading to small trauma, less bleeding and fast recovery, but also reducing complications remarkably.

The invention discloses a closed reduction device for unstable pelvic fracture minimally invasive surgery. The closed reduction device for unstable pelvic fracture minimally invasive surgery comprises a first lateral outer frame, a second lateral outer frame, a connecting outer frame, guide rails, a guide rail sliding clamp, an outer frame sliding clamp, screws and a screw clamp, wherein the second lateral outer frame is smaller than the first lateral outer frame and arranged inside the first lateral outer frame, and the first lateral outer frame and the second lateral outer frame are fixed to the guide rails through the guide rail sliding clamp; the connecting outer frame is of the structure that the arc part is connected with transverse straight rod parts, the arc part and the transverse straight rod parts are not arranged on the same plane, and the transverse straight rod parts at the two ends of the arc part are coaxially arranged in the same plane; the connecting outer fame is connected with the second lateral outer frame through the outer frame sliding clamp; the screw clamp is used for clamping the screws and fixed on the connecting outer frame. The guide rails are arranged on two sides of an operation bed. The closed reduction device for unstable pelvic fracture minimally invasive surgery can recover an unstable pelvic fracture according to a specific route, a specific angle and specific parameters, the reduction effect is good, and pain of a patient is small.

The invention discloses a transdermal screw fixation in vitro sighting device for treating pelvic fracture. According to the sighting device, the left upper end of a U-shaped calibration transmissive frame is provided with a screw exit sight with a horizontal left guide needle passage in the middle, the right upper end of the U-shaped calibration transmissive frame is provided with a screw inlet sight with a horizontal inner sleeve passage in the middle, and calibration holes are respectively arranged on left and right sidewalls of the U-shaped calibration transmissive frame; a calibration rod is fixed on the U-shaped calibration transmissive frame through the calibration holes; an inner sleeve is inserted into the screw inlet sight through the inner sleeve passage; a left fixation guide needle is inserted into the left guide needle passage; and a right fixation guide needle is inserted into the inner sleeve through a right guide needle passage arranged in the inner sleeve. The invention solves the problems of high cost, long surgery time and low accuracy of a 3D imaging navigation device. The invention applicable to most hospitals has the advantages of simple operation process, shortened operation time, rapid adjustment of screw inlet and exit points and screw fixation axis, small volume, and convenient maintenance.

The invention relates to an adjustable pelvic fracture external fixator. The adjustable pelvic fracture external fixator consists of an upper pressurizing structure, a plane boss umbrella-type insection adjusting clip, an adjusting lock structure, a locking pin structure and a stable structure. The upper pressurizing structure consists of an upper two-end threaded pipe, a front-to-back U-shaped connecting block, an internal thread rotating wheel, a ring threaded rod, a cylindrical head threaded rod, a thin round bar and a hex socket cylindrical nut; the stable structure consists of a folding stable structure and a T-shaped lock sleeve stable structure; the folding stable structure consists of a folding arc semi-ring, a folding insection semi-ring with the umbrella-type insection, an insection head U-shaped head tube, an L-shaped rod piece, and another locking pin structure; and the T-shaped lock sleeve stable structure consists of a T-shaped lock sleeve, an insection pressing bowl, another insection head U-shaped head tube, the L-shaped rod piece and the another locking pin structure. Aiming at physiology arc crown structural characteristics of the pelvic, the adjustable pelvic fracture external fixator can be adjusted, and pressurized, enables needles to be threaded at a plurality of angles, has flexible and adjustable stability for connection of the pelvic fracture, and provides a convenient fixing condition for rescuing of pelvic trauma.

The invention discloses a pelvic fracture operation steel plate interlocking device, which includes a positioning column installed with a strip-shaped steel plate fixing hole, a screw tube is arrangedon the upper part of the positioning column, and a top locking wire is installed in the screw tube. At that middle of the position column, a transverse hole penetrating through the position is arranged along the transverse direction. The positioning columns are respectively installed in the fixing holes of two independent strip-shaped steel plates, and a connecting rod is simultaneously sleeved in the positioning transverse holes of the two positioning columns and is respectively locked by a top locking wire. The invention can connect two or more independent pelvic bone fixation plates into one body in turn, and can realize effective connection and fixation no matter how the direction and angle of the combined plates are changed. Plates for pelvic fracture sites do not require a long andlarge structure to achieve high fixation strength. Multiple fragmentary fixation plates have infinite combination shapes, which can be used to fix the pelvis in any position with complex structure.

The invention discloses a multi-cavity adjustable pelvis filling water bag, which relates to the field of medical apparatus and instruments, and comprises an expansion hemostasis assembly and a liquid injection assembly; the hemostasis assembly comprises a push rod and n dilation balloons, the inner end of the push rod penetrates through the n dilation balloons and enables the n dilation balloons to be connected in series in a sealed mode, the liquid injection assembly comprises n liquid injection pipes, the inner ends of the n liquid injection pipes are communicated with inner cavities of the n dilation balloons along the push rod respectively, the outer end of each liquid injection pipe is provided with a valve body used for controlling the liquid inlet amount. Minimally invasive implantation is convenient and fast, normal saline is injected into the dilation balloon, the dilation balloon is properly dilated, hemostasis is achieved through compression of generated pressure and gravity, the pressure of pelvic cavity filling can be adjusted, angiography of a pelvic cavity is not affected, operation is easy, taking out is convenient, pain of a patient can be relieved, further damage cannot be caused, and the multi-cavity adjustable pelvis filling water bag is suitable for anterior peritoneal cavity hemostasis for severe pelvic fracture.

The invention relates to a series-parallel pelvic fracture reduction robot. The robot comprises a box body, a three-dimensional guide rail, a 3-RRR spherical parallel mechanism, a docking mechanism and an affected side pelvic clamping instrument. The three-dimensional guide rail is fixed on the box body, the 3-RRR spherical parallel mechanism is fixed on the three-dimensional guide rail, and the docking mechanism is fixed on a movable platform of the spherical parallel mechanism, so that a reduction robot system is quickly connected with the affected side pelvic clamping instrument, and preoperative disinfection is facilitated; and the docking mechanism is fixedly connected with the affected side pelvic clamping instrument, a bone needle holder is arranged on the pelvic clamping instrument and used for clamping bone needles, and a six-dimensional force sensor is arranged on the affected side pelvic clamping instrument and used for detecting the change condition of reduction force in the reduction process in real time, providing reduction force information for real-time monitoring in an operation and improving the safety of the reduction operation. The pelvic fracture reduction robot has the advantages of both a series configuration and a parallel configuration, and has the remarkable advantages of being large in working space, high in rigidity, large in bearing capacity, compact in structure, convenient to quickly connect and disinfect and the like.

The invention discloses a clinical intelligent decision support system for peripheral hip joint fracture, and relates to the technical field of a medical decision system. The clinical intelligent decision support system for peripheral hip joint fracture includes an information entry module, a diagnostic module, a decision module, a case database, wherein the preliminary diagnosis module includes aperipheral hip joint fracture classification module; the peripheral hip joint fracture classification module is based on the examination result in the information entry module, and combined with theclinical peripheral hip joint fracture classification standard for classifying the peripheral hip joint fracture; the peripheral hip joint fracture classification module classifies pelvic fractures, acetabular fractures, and hip dislocations; the pelvic fractures are classified based on injury violence-Young and Burgess, and / or based on the stability-Tile of the pelvic ring, and / or the classification criteria of tibia fracture Dennis; and the acetabular fractures are classified according to the classification criteria of Letournel-Judet. The technical solution of the clinical intelligent decision support system for peripheral hip joint fracture enables a patient and the patient's family to grasp and track the patient's condition and diagnosis and treatment plan in real time.

The invention provides a pelvic fracture front ring fixing detachable screw and an internal fixing device.The pelvic fracture front ring fixing detachable screw comprises a main screw, a screw barrel and a limiting mechanism; the through hole in the nail barrel is step-shaped; a nail head of the main nail is arranged in the nail barrel, a nail rod of the main nail penetrates out of the through hole, and the limiting mechanism is detachably connected into the nail barrel and used for limiting rotation of the main nail; when the pelvic fracture front ring fixing detachable screw is detached, the limiting mechanism is separated from the through hole, and the main nail is separated from the nail barrel after rotating by a preset angle. The internal fixing device comprises a connecting cross rod and at least two detachable screws for fixing the pelvic fracture front ring. The pelvic fracture front ring fixing detachable screws are connected through a connecting cross rod. By means of the internal fixing frame, the problem that in the prior art, for a patient provided with an internal fixing frame, other parts outside a main screw body of a screw are difficult to take out is solved, and then the postoperative discomfort of the patient can be reduced on the premise that the main screw body is reserved.

The invention discloses a pelvic locking plate system. The pelvic locking plate system comprises a locking plate and a fastening unit, wherein the locking unit comprises a support frame and a guide plate; a guide hole, which corresponds to a locking hole in the locking plate, is formed in the guide plate; in a using process, the locking plate is connected to one end of the support frame and the guide plate is connected to the other end of the support frame; and a position of the guide hole is designed as a position corresponding to the locking hole. According to the pelvic locking plate system provided by the invention, pelvic fracture can be effectively fixed, with good fitting performance; and fracture blocks can be fully reduced.

The invention relates to a pelvic fracture reduction fixing suite which is used in cooperation with an X-ray machine and is characterized in that the pelvic fracture reduction fixing suite comprises afixing frame, an adjusting frame and a positioning cylinder. wherein the fixing frame is connected to a bed body; the head end of the adjusting frame is connected to the fixing frame, the adjusting frame comprises at least three sections of adjusting rods which are sequentially connected end to end and a connecting piece for connecting every two adjacent adjusting rods, at least one connecting piece is a connecting rotating shaft, and at least one connecting piece is a connecting sleeve; the positioning cylinder is connected to the tail end of the adjusting frame, the positioning cylinder isprovided with a first positioning hole suitable for a kirschner wire to penetrate through and two second positioning holes suitable for a stimulating needle of a nerve stimulator to penetrate through,and the two second positioning holes are parallel to the first positioning hole and symmetrically formed in the two sides of the first positioning hole. The pelvic fracture reduction fixing suite issimple in structure, easy to operate and full in mechanical structure, manual operation can be achieved, the direction can be changed universally, the direction can also be fixed, the kirschner wire can accurately reach the needed position, and the success rate of resetting and fixing is increased.

The invention relates to a pelvic fracture reduction device and an operating method. The pelvic fracture reduction device comprises a near end reduction mechanism, a far end reduction mechanism and aconnecting rod, wherein the near end reduction mechanism comprises a first frame body and a first positioning assembly which is mounted on the first frame body and used for fixing skeleton at the nearend of the affected side; the far end reduction mechanism comprises a second frame body, an adjusting frame body which is hinged to the second frame body, a second positioning assembly which is mounted on the second frame body and used for fixing the skeleton at the far end of the affected side, a third positioning assembly which is arranged on the adjusting frame body and used for fixing the skeleton at the far end of the affected side; and the first frame body is connected with the second frame body through the connecting rod. Through the adoption of the pelvic fracture reduction device disclosed by the invention, the effect that after pelvic fracture and displacement occur, the skeleton at the far end of the affected side and the skeleton at the near end of the affected side are in reduction closing through the in vitro reduction device is realized; the reduction accuracy is high; the recover speed of a patient is high, the skeleton recovery effect is better, and besides, the situation that a large-range of scar is left through cutting open a fracture site is avoided.

The invention discloses a pelvis arcuate line superior border anatomical bone plate and relates to a surgical instrument manufacturing technology. The pelvis arcuate line superior border anatomical bone plate is suitable for fixing the pelvic fracture of a human body. The pelvis arcuate line superior border anatomical bone plate is a space arc curve body which is anastomotic with the shape of the inner surface of a bone at the position of a pelvis arcuate line; a fixed screw hole (3) is arranged on the plate surface; and both sides of the plate are provided with grooves (4) with the same strength. The pelvis arcuate line superior border anatomical bone plate disclosed by the invention can be used as a die plate for reduction of the pelvis arcuate line superior border fracture and is beneficial for checking the fracture reduction effect. The requirements for fixing inside different types of pelvic inlets can be met. Due to the adoption of the anatomical shape of the bone plate disclosed by the invention, the shaping time consumption in an operation is shortened; the influence of repeated shaping on the strength of the bone plate in the operation is avoided; the problems of damage to surrounding soft tissues and fracture reduction loss in the die testing process are effectively reduced; particularly, the pain of a patient is reduced; the operation risk the complications can also be effectively reduced; and the operation success rate and the treatment effect of the pelvic fracture are improved.

The invention discloses an auxiliary defecation device for a pelvic fracture patient. The auxiliary defecation device mainly comprises two herringbone supports, a rotating rod and a traction seat ring, the rotating rod is rotatably erected across the tops of the supports, and two sides of the traction seat ring are connected onto the rotating rod above the traction seat ring through twisted ropes. The two herringbone supports stand on two sides of a bend, the rotating rod is arranged on the supports through bearings, a crank is arranged at one end of the rotating rod, and a movable lock for preventing the rotating rod from automatically reversing is arranged on each herringbone support. By a pelvic suspension mode, the requirement of a pelvis for physiological anatomy and treatment is met, the patient flatly lies on the bed, the hip of the patient is slightly lifted for 1cm, a traction bag with a hole is placed at the hip and connected with the auxiliary defecation device, an assistant gradually and gently turns a handle, the hip of the patient gradually and synchronously leaves a bed surface until the hip can be plugged into an excrement receiver, the handle is fixed, and the auxiliary defecation device is connected with a bed pan, so that the patient can easily defecate.

The invention belongs to the technical field of medical instruments for orthopedics use, and specifically discloses an internal anterior pelvic ring fixation plate. The internal anterior pelvic ring fixation plate comprises a head part, a neck part, a trunk part and a tail part which are sequentially connected in a fixed way; 3 rows of head locking holes are arranged at the middle of the head part, so that locking screws can be placed in an area adjacent to the pubic symphysis; the neck part is a junction area which connects the head part and the trunk part in different planes; a neck notch isarranged above the neck part; a trunk locking hole is arranged at the middle of the trunk part, so that a locking screw can be inserted into the superior pubic branch; and a trunk notch is arranged above the trunk part; a locking hole is arranged on the tail part along an acetabulum notch, so that a channel screw can be inserted into a junction area of the ilium and the pubis. The internal anterior pelvic ring fixation plate has the following beneficial effects: the internal anterior pelvic ring fixation plate is capable of effectively fixing anterior pelvic ring fracture, so that the internal anterior pelvic ring fixation plate is suitable for pubic fracture, especially for pubic fracture near the pubic symphysis; design of the fixation plate makes fixation of the pubic fracture near thepubic symphysis more reliable; and moreover, fixation across the pubic symphysis is not required, so that loss of pubic symphysis functions can be avoided. Therefore, the internal anterior pelvic ring fixation plate is especially suitable for unmarried women for performing spontaneous delivery.

The invention discloses an external fixator for pelvic fracture, which comprises: a screw; and two sleeves both slidably mounted on the screw in sleeving manner, wherein both ends of each sleeve are fixed through nuts matched with the screws, a first connecting rod is fixedly connected to the outer wall of one sleeve vertically, a first rotating part being arranged at the tail end of the first connecting rod, the first rotating part rotates and is fixed around a central axis parallel to the screw, a bone spicule is detachably and fixedly connected to the tail end of the first rotating part andis perpendicular to the screw, a second connecting rod is fixedly connected to the outer wall of the other sleeve vertically, a second rotating part is arranged at the tail end of the second connecting rod, the second rotating part rotates and is fixed around a central axis parallel to the screw, and a bone spicule is detachably and fixedly connected to the tail end of the second rotating part. The fixator with the same specification is widely applicable and convenient to operate.

The invention belongs to the field of operation auxiliary tools, and particularly relates to a kirschner wire positioning instrument for pelvic fracture closed reduction. The kirschner wire positioning instrument comprises a reference ring, wherein an adjusting ring is arranged beside the reference ring, a spherical cavity section is arranged in an annular cavity of the adjusting ring, a sphericalhead is arranged in the spherical cavity section in a spherical fit manner, a positioning hole allowing a kirschner wire to penetrate through is coaxially formed in the spherical head relative to theadjusting ring in a penetrating manner, and the hole diameter of the positioning hole cooperates with the outer diameter of the kirschner wire to be penetrated through; and the reference ring and theadjusting ring are fixedly connected with each other through an adjusting rod capable of adjusting the length in the axial direction, and the lower ring surface of the adjusting ring and the lower ring surface of the reference ring are located on the same reference plane. Through the kirschner wire positioning instrument, the proper distance and angle can be quantitatively achieved, the operationaccuracy and safety are greatly improved, the radiation damage to a doctor and a patient due to long-time repeated fluoroscopy is reduced, and convenience and efficiency of an actual pelvic fractureclosed reduction operation are improved.

The invention discloses a pelvic fracture posterior ring minimally invasive stabilization system guide plate. The guide plate comprises a rear guide plate and a side guide plate; the rear guide plateis connected with the side guide plate; fixing holes are formed in the rear guide plate and the side guide plate; each fixing hole is used for implanting a Kirschner wire; the rear guide plate and theside guide plate are fixed through the Kirschner wires; and the rear guide plate comprises an LC2 channel screw guide pipe, and the side guide plate comprises a sacral 1 channel screw guide pipe anda sacral 2 channel screw guide pipe. According to the pelvic fracture posterior ring minimally invasive stabilization system guide plate, the combined design is adopted, the guide plate is divided into two parts, the guide plate is embedded through the two minimally invasive incisions, and the channel is established under muscles for combination. Compared with an existing guide plate scheme, the trauma is smaller.