Objective To compare the biomechanical differences among the five internal fixation modes in treatment of Day type Ⅱ crescent fracture dislocation of pelvis (CFDP), and find an internal fixation mode which was the most consistent with mechanical principles. Methods Based on the pelvic CT data of a healthy adult male volunteer, a Day type Ⅱ CFDP finite element model was established by using Mimics 17.0, ANSYS 12.0-ICEM, Abaqus 2020, and SolidWorks 2012 softwares. After verifying the validity of the finite element model by comparing the anatomical parameters with the three-dimensional reconstruction model and the mechanical validity verification, the fracture and dislocated joint of models were fixed with S1 sacroiliac screw combined with 1 LC-Ⅱ screw (S1+LC-Ⅱ group), S1 sacroiliac screw combined with 2 LC-Ⅱ screws (S1+2LC-Ⅱ group), S1 sacroiliac screw combined with 2 posterior iliac screws (S1+2PIS group), S1 and S2 sacroiliac screws combined with 1 LC-Ⅱ screw (S1+S2+LC-Ⅱ group), S2-alar-iliac (S2AI) screw combined with 1 LC-Ⅱ screw (S2AI+LC-Ⅱ group), respectively. After each internal fixation model was loaded with a force of 600 N in the standing position, the maximum displacement of the crescent fracture fragments, the maximum stress of the internal fixation (the maximum stress of the screw at the ilium fracture and the maximum stress of the screw at the sacroiliac joint), sacroiliac joint displacement, and bone stress distribution around internal fixation were observed in 5 groups. Results The finite element model in this study has been verified to be effective. After loading 600 N stress, there was a certain displacement of the crescent fracture of pelvis in each internal fixation model, among which the S1+LC-Ⅱ group was the largest, the S1+2LC-Ⅱ group and the S1+2PIS group were the smallest. The maximum stress of the internal fixation mainly concentrated at the sacroiliac joint and the fracture line of crescent fracture. The maximum stress of the screw at the sacroiliac joint was the largest in the S1+LC-Ⅱ group and the smallest in the S2AI+LC-Ⅱ group. The maximum stress of the screw at the ilium fracture was the largest in the S1+2PIS group and the smallest in the S1+2LC-Ⅱ group. The displacement of the sacroiliac joint was the largest in the S1+LC-Ⅱ group and the smallest in the S1+S2+LC-Ⅱ group. In each internal fixation model, the maximum stress around the sacroiliac screws concentrated on the contact surface between the screw and the cortical bone, the maximum stress around the screws at the iliac bone concentrated on the cancellous bone of the fracture line, and the maximum stress around the S2AI screw concentrated on the cancellous bone on the iliac side. The maximum bone stress around the screws at the sacroiliac joint was the largest in the S1+LC-Ⅱ group and the smallest in the S2AI+LC-Ⅱ group. The maximum bone stress around the screws at the ilium was the largest in the S1+2PIS group and the smallest in the S1+LC-Ⅱ group. Conclusion For the treatment of Day type Ⅱ CFDP, it is recommended to choose S1 sacroiliac screw combined with 1 LC-Ⅱ screw for internal fixation, which can achieve a firm fixation effect without increasing the number of screws.
OBJECTIVE: To explore a method of reconstruction of hip joint function after deformed healing of the upper 1/3 of fractured femur as a complication of old fracture dislocation of hip joint. METHODS: A patient with loss of function in hip joint and fusion of knee joint was treated with lock for femur intra-medullary fixation in April 1997. RESULTS: Before operation, the diseased hip joint lost its most functions and the entire lower extremity was disabled because the knee joint had been fused. One year after operation, the follow-up examination revealed that the patient could walk by crutches without discomfort, his daily life and work recovered to normal. CONCLUSION: It is effective to treat a patient suffering old fracture-dislocation of hip joint complicated with deformed healing of the upper 1/3 of fractured femur by means of individualized artificial joint replacement and a prosthesis body with lock for femur intra-medullary fixation, and it is helpful for the development of a new clinical idea to reconstruct functions in the management of some particular cases.
Objective To evaluate the deviation between actual and simulated screw placement after cervical pedicle screw placement assisted by 3D printed navigation template, and analyze the correlation between screw placement deviation and navigation pipe length. Methods A total of 40 patients undergoing cervical 1-7 pedicle screw insertion assisted by 3D printed navigation template in Zigong Fourth People’s Hospital between February 2018 and August 2020 were included in this prospective study. These patients were divided into 3 groups randomly, including 12 patients with a 5-mm pipe length (5 mm group), 13 patients with a 10-mm pipe length (10 mm group), and 15 patients with a 15-mm pipe length (15 mm group). Three-dimensional modeling was performed on preoperative cervical CT images of these patients and simulated pedicle screw was placed. Individualized pedicle screw navigation templates were designed according to the position and direction of simulated pedicle screws, and 3D printing was performed on the cervical model and navigation templates. Preoperative 3D printed model and navigation templates were used to simulate the surgical process to confirm the safety of screws. During the operation, pedicle screw placement was performed according to the preoperative design and simulated surgical process. The postoperative CT images were registered with the preoperative CT images in 3D model. The safety of screw placement was evaluated by the postoperative screw placement Grade, and the accuracy of screw placement was evaluated by measuring the deviation of screw placement point and the deviation of screw placement direction in horizontal plane (inclination angle) and sagittal plane (head inclination angle). The influence of different navigation pipe lengths on the safety and accuracy of screw placement was analyzed. Results A total of 164 pedicle screws were inserted with navigation template assistance, including 48 screws (38 in Grade 0 and 10 in Grade 1) in the 5 mm group, 52 screws in the 10 mm group (all in Grade 0), and 64 screws (52 in Grade 0 and 12 in Grade 1) in the 15 mm group, and the difference in the grade among the three groups was statistically significant (P<0.05). When the navigation pipe length was 5, 10, and 15 mm, respectively, the screw entry point deviation was (1.87±0.63), (1.44±0.63), and (1.66±0.54) mm, respectively, the inclination angle deviation was (2.72±0.25), (0.90±0.21), and (1.84±0.35)°, respectively, and the head inclination angle deviation was (8.63±1.83), (7.15±1.38), and (8.24±1.52)°, respectively. The deviations in the 10 mm group were all significantly less than those in the other two groups (P<0.05). Conclusions In the cervical pedicle screw placement assisted by navigation template, all the screws were Grade 0 or Grade 1, with high safety. The mean deviation of the screw entry point is within 2 mm, with high accuracy. When the length of navigation pipe is 10 mm, the safety and accuracy of screw placement can be fully guaranteed.
ObjectiveTo report a new type of anatomical locking plate for sternocalvicular joint, and investigate its effectiveness in treatment of sternoclavicular joint fracture and dislocation.MethodsA new type of anatomical locking plate for sternoclavicular joint was developed, which accorded with the anatomical features and biomechanical characteristics of Chinese sternoclavicular joint. By adopting the method of clinical randomized controlled study, 32 patients with the sternoclavicular joint fracture and dislocation who met the selection criteria between June 2008 and May 2015 were randomly divided into groups A and B (n=16), and the patients were treated with new anatomic locking plate and distal radial T locking plate internal fixation, respectively. There was no significant difference between 2 groups in gender, age, injured side, body mass index, cause of injury, type of injury, the time from injury to operation, and preoperative Rockwood grading score (P>0.05). The operation time, intraoperative blood loss, incision length, hospitalization time, and postoperative complications in 2 groups were recorded, and the effectiveness was evaluated by Rockwood grading score.ResultsThe operations of 2 groups completed successfully. The operation time, intraoperative blood loss, and hospitalization time in group A were significantly less than those in group B (P<0.05), but there was no significant difference in the incision length between 2 groups (t=0.672, P=0.507). All the patients were followed up 18-30 months (mean, 24 months). In group A, there were 1 case of sternoclavicular joint pain and 2 cases of wound infection; in group B, there were 1 case of sternoclavicular joint pain, 1 case of internal fixation loosening, and 1 case of sternoclavicular joint re-dislocation; there was no significant difference in complication incidence between 2 groups (P=1.000). The Rockwood grading scores at each time point after operation in 2 groups were significantly higher than those before operation. At 1 month after operation, the Rockwood grading score in group A was significantly higher than that in group B (t=2.270, P=0.031); but there was no significant difference in the Rockwood grading scores between the 2 groups at 6 months and at last follow-up (P>0.05). At last follow-up, according to the Rockwood scoring standard, the results of group A were excellent in 13 cases, good in 2 cases, poor in 1 case, the excellent and good rate was 93.75%; the results of group B were excellent in 11 cases, good in 4 cases, poor in 1 case, and the excellent and good rate was 93.75%; there was no significant difference between 2 groups (Z=–0.748, P=0.455).ConclusionThe new type of anatomic locking plate accords with the Chinese anatomical characteristics. It has the advantages of easy operative procedure, less surgical trauma, shorter operation time, less intraoperative blood loss, shorter hospitalization time, and it can achieve better results in the treatment of sternoclavicular joint fracture and dislocation.
Objective To evaluate the effectiveness of operation via anterior approach in treating pelvic crescent fra cture. Methods Between June 2007 and December 2009, 18 patients with pelvic crescent fracture were treated, including 11 males and 7 females with an average age of 32 years (range, 19-52 years). The locations were the right in 8 cases and the leftin 10 cases. Fractures were caused by traffic accident in 10 cases, by fall ing from height in 5 cases, and by crushing with heavy weights in 3 cases. All patients suffered lateral compression injuries of the pelvis. The mean time from injury to operation was 7.8 days (range, 3-22 days). The preoperative mean displacement of the posterior pelvic ring was 13.7 mm (range, 5-24 mm) according to the method described by Matta et al. The operation time, intraoperative blood loss, displacement correction of the posterior pelvic ring, fracture heal ing time, and Hannover pelvic score were recorded. Results The average operation time was 175 minutes (range, 110-230 minutes); the average intraoperative blood loss was 561.7 mL (range, 300-1 100 mL); the postoperative mean displacement of the posterior pelvic ring was 1.2 mm (range, 0-3 mm); and the mean displacement correction of the posterior pelvic ring was 12.6 mm (range, 4-23 mm). No intraoperative lumbosacral nervous injury occurred. Superficial wound infection occurred in 2 cases and was cured after 1 week of wound drainage and appl ication of antibiotic. The others achieved heal ing of incision by first intention. Fifteen patients were followed up 16.1 months on average (range, 13-22 months). The X-ray films showed fracture heal ing in all patients. The fracture heal ing time was 3.6 months on average (range, 3-4 months). No patient had loss of reduction or failure of internal fixation. The cl inical outcome was excellent in 10 cases (66.7%) and good in 5 cases (33.3%) according to Hannover pelvic score; social reintegration was complete in 13 cases (86.7%) and incomplete in 2 cases (13.3%). Conclusion Operation via anterior approach is a good choice in the treatment of pelvic crescent fracture.
Objective To investigate the effectiveness of injured vertebra fixation with inclined-long pedicle screws combined with interbody fusion for thoracolumbar fracture dislocation with disc injury. Methods Between January 2017 and June 2022, 28 patients with thoracolumbar fracture dislocation with disc injury were underwent posterior depression, the injured vertebra fixation with inclined-long pedicle screws, and interbody fusion. There were 22 males and 6 females, with a mean age of 41.4 years (range, 22-58 years). The causes of injury included falling from height in 18 cases, traffic accident in 5 cases, and bruise in 5 cases. Fracture segment included 1 case of T11, 7 cases of T12, 9 cases of L1, and 11 cases of L2. According to the American Spinal Injury Association (ASIA) scale, the spinal injuries were graded as grade A in 4 cases, grade B in 2 cases, grade C in 11 cases, and grade D in 11 cases. Preoperative spinal canal encroachment ratio was 17.7%-75.3% (mean, 44.0%); the thoracolumbar injury classification and severity score (TLICS) ranged from 9 to 10 (mean, 9.9). Seventeen patients were associated with other injuries. The time from injury to operation ranged from 1 to 4 days (mean, 2.3 days). The perioperative indicators (operation time, intraoperative blood loss, and the occurrence of complications), clinical evaluation indicators [visual analogue scale (VAS) score and Oswestry Disability Index (ODI)], radiologic evaluation indicators [anterior vertebral height ratio (AVHR), kyphosis Cobb angle (KCA), intervertebral space height (ISH), vertebral wedge angle (VWA), displacement angle (DA), and percent fracture dislocation displacement (PFDD)], neurological function, and interbody fusion were recorded. Results The operation time was 110-159 minutes (mean, 130.2 minutes). The intraoperative blood loss was 200-510 mL (mean, 354.3 mL). All incisions healed by first intention, and no surgical complications such as wound infection or hematoma occurred. All patients were followed up 12-15 months (mean, 12.7 months). The chest and lumbar pain significantly relieved, VAS scores and ODI after operation were significantly lower than those before operation, and further decreased with the extension of postoperative time, with significant differences (P<0.05). At last follow-up, the ASIA classification of neurological function of the patients was grade A in 3 cases, grade B in 1 case, grade C in 1 case, grade D in 10 cases, and grade E in 13 cases, which was significantly different from preoperative one (Z=−4.772, P<0.001). Imaging review showed that AVHR, KCA, ISH, VWA, DA, and PFDD significantly improved at 1 week, 3 months and last follow-up (P<0.05). There was no significant difference between different time points after operation (P>0.05). At last follow-up, according to the modified Brantigan score, all patients achieved good intervertebral bone fusion, including 22 complete fusion and 6 good intervertebral fusion with a few clear lines. No complications such as internal fixation failure or kyphosis occurred during follow-up.Conclusion The injured vertebra fixation with inclined-long pedicle screws combined with interbody fusion is an effective treatment for thoracolumbar fracture dislocation with disc injury, which can correct the fracture dislocation, release the nerve compression, restore the injured vertebral height, and reconstruct spinal stabilization.