Objective To evaluate the fixation technique of using the cervical lateral mass plate in the cervical posterior approach operation. Methods Eight patients in this group were admitted from September 2001 to November 2006. Among the 8 patients, there were 6 males and 2 females, with their ages ranging from 28 to 78 years. Cervical vertebral fracture with dislocation was found in 4 patients, C2 spinal cord injury in 1, C1 fracture in 1, cervical spinal stenosis in 1, and C2-5 spinal cord neurofibroma in 1. Muscle strength 3-4. TheFrankel grading system was usedin 6 patients with traumatic injury. Before operation, Grade C was observed in 2patients，Grade D in 3，and Grade E in 1. All the operations were performed according to requirements of the Margel’s method. We positioned 40 screws in all the patients, including 4 screws at C2，6 screws at C3，12 screws at C4，4 screws at C5，4 screws at C6，2 screws at C7，and 6 screws at T1. Results The followingup for an average of 14.1 months (range,645 months) revealed that there was no malposition of the screws in the patients. One of the 8 patients developed spinal instability in the fixed segment at 3 months after operation. The headchestbrace was applied to the patient for 3 months, and the spinal fusion was achieved. The further followingup to 45 months indicated that there was no instability occurring. The remaining patients recovered to their spinal stability by the spinal fusion. The patients also recovered in their neurological function after operation. The Frankel assessment showed that 1 patient had Grade E, 3 from Grade D to Grade E, 1 from Grade C to Grade D, and 1 from Grade C to Grade E. Conclusion The cervical lateral mass plate fixation can provide the immediate and b segmental immobilization for the good cervical spine stability.
Objective To provide the anatomic basis for thelag screw placement in the anterior column of the acetabulum. Methods Twenty-two pelvis specimens with 44 acetabula of the native adult cadavers were studied. The anthropometric measurement was performed on 44 acetabula to determine the shape of the transverse section of the anterior column of the acetabulum, the optimal entry point for the lag screw on the outer table of the ilium, the direction of the screw, and the distance from the entry point to the obturator groove. Results The transverse section of the anterior column of the acetabulum was almost triangle-shaped. The path for the lag screw placement was 10.5±0.8 mm in diameter. The optimal entry point on the posterolateral ilium for the screw fixation was found toexist 9.2±2.4 mm superior to the line between the anterior superior iliac spine and the greater sciatic notch and 38.5±3.8 mm superior to the greater sciatic notch. The distance from the entry point to the obturator groove was 84.1±6.2 mm. The inclination of the lag screw was 54.2±5.5° at the caudal direction in the sagittal plane and 40.7±3.8° in the horizontal plane. The device for the safe screw placement in the anterior column was designed. Conclusion The above datacan facilitate an insertion of one 6.5 mm lag screw into the anterior acetabular column and minimize the risk of articular violation or cortical penetration, which has a narrow margin of safety. The safe length of the lag screw should be 70 mm.The optimal entry point on the posterolateral ilium for the screw fixationis determined to be 10 mm superior to the line between the anterior superior iliac spine and the greater sciatic notch and 40 mm superior to the greater sciatic notch. The inclination of the lag screw should be 55° at the caudal direction in the sagittal plane and 40° in the horizontal plane. It is safe to place thelag screw in the anterior column with the help of the targeting device.
ObjectiveTo compare the effectiveness of open reduction of posterior cruciate ligament (PCL) avulsion fracture at tibial insertion of knee joint with absorbable screws fixation and absorbable screw combined with suture anchor fixation. Methods The clinical data of 26 patients with PCL avulsion fracture at tibial insertion who met the selection criteria between March 2015 and October 2021 were retrospectively analyzed. Among them, 14 patients were fixed with simple absorbable screw (group A), and 12 patients were fixed with absorbable screw combined with suture anchors (group B). All patients were confirmed by X-ray film, CT, or MRI preoperatively, and got positive results in preoperative posterior drawer tests. There was no significant difference in gender, age, side of affected limb, time from injury to operation, comorbidities, and preoperative Meyers & McKeever classification, Lysholm score, and International Knee Documentation Committee (IKDC) score between the two groups (P>0.05). The operation time and postoperative complications were recorded and compared between the two groups. At last follow-up, Lysholm score and IKDC score were used to evaluate the improvement of knee function. ResultsThere was no significant difference in operation time between the two groups (P>0.05). All incisions healed by first intention, and no complication such as vascular and nerve injury or venous thrombosis occurred. All 26 patients were followed up 9-89 months, with an average of 55.3 months. The follow-up time of group A and group B was (55.7±23.2) and (56.8±29.3) months, respectively, with no significant difference (t=−0.106, P=0.916). Radiographs showed bone healing in both groups at 3 months after operation, and no complication such as infection and traumatic arthritis occurred. At last follow-up, the posterior drawer test was negative in both groups, and the Lysholm score and IKDC score significantly improved when compared with the pre-operative values (P<0.05). However, there was no significant difference in the improvement value between the two groups (P>0.05). ConclusionFor PCL avulsion fracture at tibial insertion of the knee joint, the open reduction and absorbable screw combined with suture anchor fixation can achieve reliable fracture reduction and fixation, which is conducive to the early rehabilitation and functional exercise, and the postoperative functional recovery of the knee joint is satisfactory.
ObjectiveTo explore the effectiveness of hollow screw for the treatment of basilar part fracture of hamate hook.MethodsFive patients with basilar part fracture of hamate hook, aged 24-47 years (mean, 31 years) were treated with open reduction and hollow screw fixation between June 2015 and February 2019. There were 4 males and 1 female. The causes of injury were athletic injury in 3 cases, falling injury in 1 case, and crushing injury in 1 case. Among them, 1 case was combined with sensory disturbance of one and a half fingers on the ulnar side of the palm. The grip strength of the affected side was significantly decreased when compared with that of the healthy side in all patients. The intervals between injury and surgery were 3-8 days (mean, 4.2 days). Postoperative follow-up was conducted regularly to measure the grip strength of the affected and healthy fingers and the total motion of ring and little fingers of the affected side. Darrow criteria was used to evaluate the effectiveness.ResultsAll the incisions healed by primary intention. All the patients were followed up 6-32 months (mean, 16 months). X-ray films showed that the basilar part fracture of hamate hook reached bony union, and the healing time was 2.0-3.5 months (mean, 2.2 months). At last follow-up, the grip strength of the affected side was (35.80±3.76) kg, showing no significant difference when compared with healthy side [(36.00±4.94) kg] (t=0.094, P=0.930); and the total motion of ring and little fingers of the affected side was (529.0±8.9)°, which was significantly different from that before operation [(232.0±34.7)°] (t=18.108, P=0.000). In 1 patient with ulnar nerve injury, the two-point discrimination of the innervation area was 4 mm, and the pain sensation and temperature sensation returned to normal. Assessed by Darrow criteria, the results were excellent in 4 cases and good in 1 case.ConclusionFor the basilar part fracture of hamate hook, hollow screw fixation can obtain secure reduction and fixation and provide sustained compression and counter-rotation for the broken end of fracture, thus allowing early joint motion and promoting fracture healing and recovery of wrist function. It is a relatively good method for the treatment of basilar part fracture of hamate hook.
Objective To evaluate the biomechanical stability of a newly-designed Y type pedicle screw (YPS) in osteoporotic synthetic bone. Methods The osteoporotic synthetic bone were randomly divided into 3 groups (n=20). A pilot hole, 3.0 mm in diameter and 30.0 mm in deep, was prepared in these bones with the same method. The YPS, expansive pedicle screw (EPS), and bone cement-injectable cannulated pedicle screw (CICPS) were inserted into these synthetic bone through the pilot hole prepared. X-ray film examination was performed after 12 hours; the biomechanical stability of YPS, EPS, and CICPS groups was tested by the universal testing machine (E10000). The test items included the maximum axial pullout force, the maximum running torque, and the maximum periodical anti-bending. Results X-ray examination showed that in YPS group, the main screw and the core pin were wrapped around the polyurethane material, the core pin was formed from the lower 1/3 of the main screw and formed an angle of 15° with the main screw, and the lowest point of the inserted middle core pin was positioned at the same level with the main screw; in EPS group, the tip of EPS expanded markedly and formed a claw-like structure; in CICPS group, the bone cement was mainly distributed in the front of the screw and was dispersed in the trabecular bone to form a stable screw-bone cement-trabecular complex. The maximum axial pullout force of YPS, EPS, and CICPS groups was (98.43±8.26), (77.41±11.41), and (186.43±23.23) N, respectively; the maximum running torque was (1.42±0.33), (0.96±0.37), and (2.27±0.39) N/m, respectively; and the maximum periodical anti-bending was (67.49±3.02), (66.03±2.88), and (143.48±4.73) N, respectively. The above indexes in CICPS group were significantly higher than those in YPS group and EPS group (P<0.05); the maximum axial pullout force and the maximum running torque in YPS group were significantly higher than those in EPS group (P<0.05), but there was no significant difference in the maximum periodical anti-bending between YPS group and EPS group (P>0.05). Conclusion Compared with EPS, YPS can effectively enhance the maximum axial pullout force and maximum rotation force in the module, which provides a new idea for the design of screws and the choice of different fixation methods under the condition of osteoporosis.
ObjectiveTo develop an instrument for sacroiliac joint fixation with less injury and less complications. MethodsFirstly, 18 adult pelvic specimens (8 males and 10 females) were used to measure the anatomical data related to the locking plates and locking screws on the sacrum and ilium, and the polyaxial locking plate screw system of the sacroiliac joint was designed according to the anatomic data. This system was made of medical titanium alloy. Then 4 adult male plevic specimens were harvested and the experiment was divided into 3 groups:group A (normal pelvic), group B (the dislocated sacroiliac joint fixed with sacroiliac screws), and group C (the dislocated sacroiliac joint fixed with polyaxial locking plate screw system). The vertical displacement of sacroiliac joint under the condition of 0-700 N vertical load and the horizontal displacement on angle under the condition of 0-12 N·m torsional load were compared among the 3 groups by using the biological material test system. Finally, the simulated application test was performed on 1 adult male cadaveric specimen to observe soft tissue injury and the position of the locking plate and screw by X-ray films. ResultsAccording to the anatomic data of the sacrum and ilium, the polyaxial locking plate screw system of the sacroiliac joint was designed. The biomechanical results showed that the vertical displacement of the sacroiliac joint under the condition of 0-700 N vertical load in group A was significantly bigger than that in group B and group C (P < 0.05), but there was no significant difference between group B and group C (P>0.05). The horizontal displacement on angle under the condition of 0-12 N·m torsional load in group A was significantly less than that in group B and group C (P < 0.05). The horizontal displacement on angle under the condition of 0-6 N·m torsional load in group B was bigger than that in group C, and the horizontal displacement on angle under the condition of 6-12 N·m torsional load in group B was less than that in group C, but there was no significant difference between group B and group C (P>0.05). The test of simulating application showed that the specimen suffered less soft tissue injury, and this instrument could be implanted precisely and safely. ConclusionThe polyaxial locking plate screw system of the sacroiliac joint has the advantages of smaller volume and less injury; polyaxial fixation enables flexible adjustment screw direction. The simulated application test shows satisfactory fixing effect.
Objective To explore the clinical application value of the spinal robot-assisted surgical system in mild to moderate lumbar spondylolisthesis and evaluate the accuracy of its implantation. Methods The clinical data of 56 patients with Meyerding grade Ⅰ or Ⅱ lumbar spondylolisthesis who underwent minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) between January 2017 and December 2017 were retrospectively analysed. Among them, 28 cases were preoperatively planned with robotic arm and percutaneous pedicle screw placement according to preoperative planning (group A); the other 28 cases underwent fluoroscopy-guided percutaneous pedicle screw placement (group B). There was no significant difference in gender, age, body mass index, slippage type, Meyerding grade, and surgical segmental distribution between the two groups (P>0.05). The screw insertion angle was measured by CT, the accuracy of screw implantation was evaluated by Neo’s criteria, and the invasion of superior articular process was evaluated by Babu’s method. Results One hundred and twelve screws were implanted in the two groups respectively, 5 screws (4.5%) in group A and 26 screws (23.2%) in group B penetrated the lateral wall of pedicle, and the difference was significant (χ2=9.157, P=0.002); the accuracy of nail implantation was assessed according to Neo’s criteria, the results were 107 screws of degree 0, 3 of degree 1, 2 of degree 2 in group A, and 86 screws of degree 0, 16 of degree 1, 6 of degree 2, 4 of degree 3 in group B, showing significant difference between the two groups (Z=4.915, P=0.031). In group B, 20 (17.9%) screws penetrated the superior articular process, while in group A, 80 screws were removed from the decompression side, and only 3 (3.8%) screws penetrated the superior articular process. According to Babu’s method, the degree of screw penetration into the facet joint was assessed. The results were 77 screws of grade 0, 2 of grade 1, 1 of grade 2 in group A, and 92 screws of grade 0, 13 of grade 1, 4 of grade 2, 3 of grade 3 in group B, showing significant difference between the two groups (Z=7.814, P=0.029). The screw insertion angles of groups A and B were (23.5±6.6)° and (18.1±7.5)° respectively, showing significant difference (t=3.100, P=0.003). Conclusion Compared to fluoroscopy-guided percutaneous pedicle screw placement, robot-assisted percutaneous pedicle screw placement has the advantages such as greater accuracy, lower incidence of screw penetration of the pedicle wall and invasion of the facet joints, and has a better screw insertion angle. Combined with MIS-TLIF, robot-assisted percutaneous pedicle screw placement is an effective minimally invasive treatment for lumbar spondylolisthesis.
Objective To evaluate the accuracy of pedicle guide device for the placement of the pedicle screws. Methods Pedicle guide device was designed and made for the anatomical trait of pedicle. The 3-Danatomical data of the thoracic pedicles were measured by multislice spiral CT in two embalmed human cadaveric thoracic pedicles spine(T1 -T10). Depending on transverse section angle(TSA) and sagittal section angle(SSA) of pedicle axis, the degree of horizontal dial and sagittal dial were adjusted in the guide device. The screws wereinserted bilaterally in the thoracic pedicles by using the device. After pulling the screws out, the pathways were filled with contrast media. The TSA and SSA of developed pathways were measured. Results Analysis of the difference between pedicle axis and developed pathway was of no statistical significance(P＞0.05). Conclusion The guide device could be easilyoperated and guarantee high accuracy of the pathways of screws and the incidence of pedicle penetration could be significantly reduced.
ObjectiveTo compare the effectiveness of the femoral neck system (FNS) and inverted triangle cannulated screws (ITCS) for the treatment of Pauwels type Ⅲ femoral neck fractures.MethodsThe clinical data of 59 patients with Pauwels type Ⅲ femoral neck fractures treated between May 2019 and November 2020 were retrospectively analysed. The patients were divided into FNS group (28 cases) and ITCS group (31 cases) according to the different internal fixation. There was no significant difference in gender, age, affected side, body mass index, cause of injury, smoking history, alcohol abuse history, Pauwels angle, Garden classification, AO/Orthopaedic Trauma Association (AO/OTA) classification, and time from injury to operation between the two groups (P>0.05). The operation time, incision length, intraoperative blood loss, extra assisted reduction procedures (Kirschner wire prying reduction or open reduction), hospitalization stay, and early complications were recorded and compared between the two groups. Garden index and Haidukewych score were used to evaluate fracture reduction. Fracture healing time, lateral thigh irritation, time of partial or total weight-bearing postoperatively, shortening length and degree of femoral neck, change of caput-collum-diaphysis (CCD) angle (the difference of CCD angle between immediate after operation and last follow-up), incidence of osteonecrosis of femoral head and revision surgery were recorded and compared between the two groups. Hip joint function were evaluated by Harris score.ResultsThe operation time of FNS group was significantly shorter than ITCS group, and the incision length was significantly longer than ITCS group (P<0.05). There was no significant difference in intraoperative blood loss, assisted reduction, Garden index, Haidukewych score, and hospitalization stay between the two groups (P>0.05). All the incisions healed by first intention. There were 2 deep vein thrombosis in the FNS group and 1 pulmonary infection and 1 deep vein thrombosis in the ITCS group. No significant difference was found in the incidence of early postoperative complications (7.1% vs. 6.5%) between the two groups (P=1.000). Patients in both groups were followed up 3-14 months, and there was no significant difference in follow-up time between the two groups (t=–0.553, P=0.582). The fracture healing time, Harris score, and the partial weight-bearing time after operation of the FNS group were significantly better than those of the ITCS group (P<0.05). However, there was no significant difference in total weight-bearing time between the two groups (Z=–1.298, P=0.194). No lateral thigh irritation was found in the FNS group, while 10 patients in the ITCS group had lateral thigh irritation, and the incidence between the two groups (0 vs. 32.3%) was significant (P=0.001). At last follow-up, the shortening length and degree of femoral neck and the change of CCD angle in FNS group were significantly less than those in ITCS group (P<0.05). There was no patient with osteonecrosis of femoral head or reoperation in the FNS group, while 4 patients in the ITCS group underwent reoperation (including 2 cases of osteonecrosis of the femoral head). However, the incidences (0 vs. 6.5%; 0 vs. 12.9%) between the two groups were not significant (P=0.493; P=0.114).ConclusionUsing FNS to treat Pauwels type Ⅲ femoral neck fracture is simple as well as able to reduce the shortening of the femoral neck and the change of the CCD angle. Also, FNS is conducive to the recovery of hip joint function, which should be considered as a new choice for the treatment of young femoral neck fracture patients.
Objective To investigate the effectiveness of sacroiliac screw implantation assisted by three-dimensional (3D) printed faceted honeycomb guide plate in the treatment of posterior pelvic ring fracture. Methods The clinical data of 40 patients with posterior pelvic ring fractures treated with sacroiliac screw implantation between December 2019 and December 2022 were retrospectively analyzed. Among them, 18 cases were treated with sacroiliac screws fixation assisted by 3D printed faceted honeycomb guide plate (guide plate group), and 22 cases were treated with sacroiliac screws percutaneously fixation under fluoroscopy (conventional group). There was no significant difference in baseline data (P>0.05) such as gender, age, time from injury to operation, and Dennis classification between the two groups. The implantation time, frequency of C-arm X-ray fluoroscopy, frequency of guide pin adjustment of each sacroiliac screw, and postoperative complications and bone healing were recorded. Majeed score was used to evaluate the functional recovery at 6 months after operation, and CT was used to observe whether the screw penetrated the bone cortex. The deviation between the virtual position and the actual position of the screw tip, the sacral foramen, and the screw entry point was measured on the sagittal CT images of the guide plate group. Results The number of screws implanted in S1 and S2 vertebral bodies was 14 and 16 respectively in the guide plate group, and 17 and 18 respectively in the conventional group. The implantation time of each sacroiliac screw, the frequency of C-arm X-ray fluoroscopy, and the frequency of guide pin adjustment in S1, S2, and all vertebrae in the guide plate group were significantly less than those in the conventional group (P<0.05). Patients in both groups were followed up 8-48 months, with an average of 19.7 months. There was no incision infection, screw displacement, or internal fixation loosening in both groups. Callus growth was observed in all patients at 12 weeks after operation, and bone healing was achieved in all patients. The healing time ranged from 12 to 24 weeks, with an average of 15.7 weeks. No sacroiliac screw penetrated the bone cortex in the guide plate group; 2 patients in the conventional group had sacroiliac screws penetrating the bone cortex without damaging blood vessels or nerves. In the guide plate group, the deviation between the virtual position and the actual position of the screw tip, the sacral foramen, and the screw entry point were (2.91±1.01), (2.10±0.74), and (1.67±0.70) mm, respectively, with an average deviation of (2.19±1.22) mm. There was no significant difference in Majeed function evaluation between the two groups at 6 months after operation (P>0.05). Conclusion The application of 3D printed faceted honeycomb guide plate in sacroiliac screw implantation for posterior pelvic ring fracture can shorten the screw implantation time, reduce the frequency of fluoroscopy and guide pin adjustment, and reduce the risk of screw penetration through the bone cortex.