A new mathematical model for evaluating surface changes in the mid-abdominal sagittal plane after two-level pedicle reduction osteotomy in patients with ankylosing spondylitis.

BACKGROUND: The purpose of this study was to create a mathematical model to precalculate the acreage change in the abdominal median sagittal plane (ac-AMSP) of patients with ankylosing spondylitis (AS) for whom two-level pedicle subtraction osteotomy (PSO) was planned. METHODS: A single-centre retrospective review of prospectively collected data was conducted among 11 adults with AS. Acreage of the abdominal median sagittal plane (a-AMSP) was performed. The distances and angles between the osteotomy apexes, anterosuperior edge of T12, xiphoid process, superior edge of the pubis, and anterosuperior corner of the sacrum were measured on preoperative thoracolumbar computed tomography. A mathematical model was created using basic trigonometric functions in accordance with the abdominal parameters. Planned osteotomized vertebra angles (POVAs) were substituted into the mathematical model, and the predictive ac-AMSP (P-AC) was obtained. A paired sample t test was performed to determine the differences between the P-AC and actual ac-AMSP (A-AC) and between the predictive acreage change rate (P-CR) and actual acreage change rate (A-CR). RESULTS: The mean age and GK were 44.4 ± 8.99 years and 102.9° ± 19.17°, respectively. No significant difference exists between A-CR and P-CR via mathematical modeling (p > 0.05). No statistically significant difference existed between POVA and actual osteotomized vertebra angles (AOVA) (p > 0.05). A statistically significant difference was observed between preoperative and postoperative measurements of LL, SVA, and GK variables (p < 0.001). CONCLUSIONS: The novel mathematical model was reliable in predicting the ac-AMSP in AS patients undergoing two-level PSO.

[Preoperative standing to prone spinal-pelvic sagittal parameter changes in old traumatic spinal fractures with kyphosis].

Objective: To investigate the changes in spinal-pelvic sagittal parameters from preoperative standing to prone position in old traumatic spinal fractures with kyphosis. Methods: The clinical data of 36 patients admitted between December 2016 and June 2021 for surgical treatment of old traumatic spinal fractures with kyphosis, including 7 males and 29 females, aged from 50 to 79 years (mean, 63.9 years), were retrospectively analyzed. Lesion segments included 2 cases of T 11, 12 cases of T 12, 2 cases of T 11, 12, 4 cases of T 12 and L 1, 12 cases of L 1, 2 cases of L 2, 1 case of L 2, 3, and 1 case of L 3. The disease duration ranged from 4 to 120 months, with an average of 19.6 months. Surgical procedures included Smith-Petersen osteotomy in 4 cases, Ponte osteotomy in 6 cases, pedicle subtraction osteotomy in 2 cases, and improved fourth level osteotomy in 18 cases; the remaining 6 cases were not osteotomized. The bone mineral density ranged from -3.0 to 0.5 T, with a mean of -1.62 T. The spinal-pelvic sagittal parameters from preoperative standing to prone positions were measured, including local kyphosis Cobb angle (LKCA), thoracic kyphosis (TK), lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT), and PI and LL mismatch (PI-LL). The kyphotic flexibility=(preoperative standing LKCA-preoperative prone LKCA)/preoperative standing LKCA×100%. Spinal-pelvic sagittal parameters were compared between standing position and prone position before operation, and Pearson correlation was used to judge the correlation between the parameters of standing position and prone position before operation. Results: When the position changed from standing to prone, LKCA and TK decreased significantly ( P<0.05), while SS, LL, PT, and PI-LL had no significant difference ( P>0.05). Pearson correlation analysis showed that LL was significantly correlated with SS and PI-LL in both standing and prone positions ( P<0.05), and the correlation strength between LL and SS in prone position was higher than that in standing position. In the standing position, LKCA was significantly correlated with SS and PT ( P<0.05). However, when the position changed from standing to prone, the correlation between LKCA and SS and PT disappeared, while PT and PI-LL was positive correlation ( P<0.05). The kyphotic flexibility was 25.13%-78.79%, with an average of 33.85%. Conclusion: For the patients of old traumatic spinal fractures with kyphosis, the preoperative LKCA and TK decrease significantly from standing position to prone position, and the correlation between spinal and pelvic parameters also changed, which should be taken into account in the formulation of preoperative surgical plan.

[Effect of injury degree of osteoporotic vertebral compression fracture on bone cement cortical leakage after percutaneous kyphoplasty].

Objective: To analyze the correlation between bone cement cortical leakage and injury degree of osteoporotic vertebral compression fracture (OVCF) after percutaneous kyphoplasty (PKP), and to provide guidance for reducing clinical complications. Methods: A clinical data of 125 patients with OVCF who received PKP between November 2019 and December 2021 and met the selection criteria was selected and analyzed. There were 20 males and 105 females. The median age was 72 years (range, 55-96 years). There were 108 single-segment fractures, 16 two-segment fractures, and 1 three-segment fracture. The disease duration ranged from 1 to 20 days (mean, 7.2 days). The amount of bone cement injected during operation was 2.5-8.0 mL, with an average of 6.04 mL. Based on the preoperative CT images, the standard S/H ratio of the injured vertebra was measured (S: the standard maximum rectangular area of the cross-section of the injured vertebral body, H: the standard minimum height of the sagittal position of the injured vertebral body). Based on postoperative X-ray films and CT images, the occurrence of bone cement leakage after operation and the cortical rupture at the cortical leakage site before operation were recorded. The correlation between the standard S/H ratio of the injured vertebra and the number of cortical leakage was analyzed. Results: Vascular leakage occurred in 67 patients at 123 sites of injured vertebrae, and cortical leakage in 97 patients at 299 sites. Preoperative CT image analysis showed that there were 287 sites (95.99%, 287/299) of cortical leakage had cortical rupture before operation. Thirteen patients were excluded because of vertebral compression of adjacent vertebrae. The standard S/H ratio of 112 injured vertebrae was 1.12-3.17 (mean, 1.67), of which 87 cases (268 sites) had cortical leakage. The Spearman correlation analysis showed a positive correlation between the number of cortical leakage of injured vertebra and the standard S/H ratio of injured vertebra ( r=0.493, P<0.001). Conclusion: The incidence of cortical leakage of bone cement after PKP in OVCF patients is high, and cortical rupture is the basis of cortical leakage. The more severe the vertebral injury, the greater the probability of cortical leakage.

[Application of TightRope system combined with Locking-Loop biplane anatomical reconstruction technique for acute acromioclavicular joint dislocation].

Objective: To investigate the effectiveness of TightRope system combined with Locking-Loop biplane anatomical reconstruction technique in the treatment of acute acromioclavicular joint dislocation. Methods: A clinical data of 28 patients with acute acromioclavicular joint dislocation who met the selection criteria and admitted between June 2018 and December 2021 was retrospectively analyzed. There were 18 males and 10 females, with an average age of 47.7 years (range, 22-72 years). The causes of injury included falling (13 cases) and traffic accidents (15 cases). The acromioclavicular joint dislocation was rated as Rockwood type Ⅲ in 7 cases, type Ⅳ in 16 cases, and type Ⅴ in 5 cases. The time from injury to operation was 4-13 days, with an average of 9.5 days. The acromioclavicular joint dislocation was reconstructed with TightRope system and high-strength wire by Locking-Loop methods during operation. The operation time and complications were recorded. Visual analogue scale (VAS) score, Constant-Murley score, and active range of motion of shoulder (forward flexion and upward lift, abduction and upward lift, and external rotation) were recorded before operation and at 12 months after operation to evaluate the functional recovery of shoulder. The loss of acromioclavicular joint reduction was assessed by comparing the coracoclavicular distance (CCD) based on the anteroposterior X-ray films at 3 days and 12 months after operation. Results: The operation time was 58-100 minutes (median, 85 minutes). All incisions healed by first intention. All patients were followed up 12 months. During follow-up, 2 patients developed shoulder adhesion, which recovered after rehabilitation exercise. At 12 months after operation, the VAS score was significantly lower, the Constant-Murley score was significantly higher, and the range of motion of the shoulder joint (forward flexion and upward lift, abduction and upward lift, and external rotation) significantly increased when compared with preoperative ones ( P<0.05). X-ray films showed that the CCD was 8.4 (7.3, 9.4) and 9.2 (8.1, 10.1) mm at 3 days and 12 months after operation, respectively, with a significant difference ( Z=-4.665, P<0.001). During follow-up, there was no complication such as infection, titanium plate entrapment, fracture, internal fixation failure, or redislocation. Conclusion: The treatment of acute acromioclavicular joint dislocation with TightRope system combined with Locking-Loop biplane anatomical reconstruction has the advantages of small incision, joint reduction under direct vision, high fixation strength, and low incidence of postoperative complications, which can effectively relieve the pain of patients' shoulder joint and facilitate the recovery of shoulder joint function.

[Effectiveness analysis of Endobutton plate combined with high-strength suture Nice knot fixation in the treatment of distal clavicle fractures].

OBJECTIVE: To investigate the effectiveness of Endobutton plate coracoclavicular fixation combined with fracture site high-strength suture Nice knot cerclage fixation in the treatment of distal clavicle fracture with coracoclavicular ligament injury. METHODS: The clinical data of 33 cases of distal clavicular fracture with coracoclavicular ligament injury treated by Endobutton coracoclavicular plate fixation between January 2017 and December 2020 were analyzed retrospectively. According to the fixation methods of fracture site, they were divided into two groups: the high-strength suture Nice knot fixation group (study group, 16 cases) and the transacromial Kirschner wire fixation group (control group, 17 cases). There was no significant difference between the two groups in common data such as age, gender, injury side, cause of injury, Craig type, combined injury, time from injury to operation, and preoperative visual analogue scale (VAS) score and Constant-Murley score ( P>0.05). Postoperative fracture healing and complications were observed, and the increase rate of coracoclavicular space on the affected side was calculated at last follow-up. VAS score was used to evaluate shoulder pain before operation, at 1 week, 1 month, 3 months after operation, and at last follow-up. The shoulder function was evaluated according to Constant-Murley shoulder score before operation, at 1 month, 3 months after operation, and at last follow-up. RESULTS: The operations were successfully completed in both groups without severe complications such as vascular nerve injury and coracoid fracture. In the control group, 1 case (5.9%) had slight pin tract infection and 1 case (5.9%) had Kirschner wire displacement; there was no obvious complication in the study group. The patients in both groups were followed up 9-36 months (mean, 22.9 months). The fracture healing time of the study group and the control group were (12.56±0.73) weeks and (13.59±0.87) weeks, respectively, and the difference was significant ( t=-3.661, P=0.001). At last follow-up, the increase rates of coracoclavicular space on the affected side of the study group and the control group were 8.88%±1.19% and 8.55%±1.07%, respectively, showing no significant difference ( t=0.837, P=0.409). The postoperative VAS score and Constant-Murley score of the two groups significantly improved when compared with those before operation, and the two scores gradually improved with the extension of time after operation ( P<0.05). Except that the VAS score at 1 week and 1 month after operation and the Constant-Murley score at 1 month after operation in the study group were significantly better than those in the control group ( P<0.05), there was no significant difference between the two groups at other time points after operation ( P>0.05). CONCLUSION: For oblique fracture or combined with butterfly fracture in the distal clavicle fracture with coracoclavicular ligament injury, the fracture site high-strength suture Nice knot fixation is a good supplement to the Endobutton plate coracoclavicular fixation. It can stabilize the fracture end, reduce the complications of Kirschner wire fixation, and is more conducive to fracture healing. The effectiveness is satisfactory.

An innovative adjustable prone positioning frame for treatment of severe kyphosis secondary to ankylosing spondylitis with two-level osteotomy.

PURPOSE: This study aims to introduce an innovative adjustable prone positioning frame (APPF) and explore its feasibility and safety for treatment of severe kyphosis secondary to ankylosing spondylitis (AS) with two-level osteotomy. METHODS: A retrospective, non-controlled study was conducted to illustrate the process where 13 patients diagnosed with severe kyphosis secondary to AS received operations on the APPF. Parameters of chin brow vertical angle (CBVA), global kyphosis (GK), thoracolumbar kyphosis (TLK), lumbar lordosis (LL) and sagittal vertical axis (SVA) were measured. Positioning time, operation time, intraoperative blood loss ahd complications were also determined. The Scoliosis Research Society outcomes instrument (SRS-22) was applied for clinical assessment. RESULTS: All patients were placed on the APPF successfully with the positioning time of 2.92 ± 0.76 min, received operation with 457.00 ± 88.04 min and had blood loss of 2330.77 ± 1423.25 ml. Four cases experienced pain due to tensional skin of the abdomen and one case suffered cerebrospinal fluid leakage postoperatively, but these patients were all cured conservatively. No neurological complications were observed, although sagittal translation occurred in four patients. Significant improvements were detected in CBVA, GK, TLK, LL and SVA postoperatively (P < 0.05), but no significant difference was observed between postoperation and the final follow-up (P > 0.05). The SRS-22 scores at 2 years after operation were significantly higher than those before operation (P < 0.05). CONCLUSION: The innovative APPF provided great convenience to place patients with severe kyphosis secondary to AS in a prone position. Performing two-level osteotomy with the aid of APPF is safe, feasible and effective.

Anterior column opening structural bone grafting with posterior column compression technique for the treatment of obsolete vertebral compression fractures with severe spinal kyphosis.

OBJECTIVES: We aimed to evaluate the efficacy and safety of anterior column opening structural bone grafting with posterior column compression technique for the treatment of obsolete vertebral compression fractures with severe spinal kyphosis. METHODS: Fourteen patients with senile obsolete vertebral compression fractures and severe spinal kyphosis were admitted to our hospital. During the treatment processing, an "eggshell" osteotomy, anterior column opening structural bone grafting with posterior column compression, and pedicle screw internal fixation were performed in all patients. The Cobb angle, Visual Analogue Scale (VAS) score, Oswestry Disability Index (ODI) pre-operatively, post-operatively, and at the last follow-up were analyzed. Furthermore, the intra-operative blood loss and the operative time were also analyzed. RESULTS: The average osseous fusion time was 3.6 months (range from 3 to 5 months). The average operative time was 236 ± 20.1 min (range from 198 to 261 min). The average intra-operative blood loss was 1350.5 ± 70.2 ml (range from 809 to 2216 ml). The Cobb angle of localized kyphosis was 63.4 ± 12.4∘ pre-operatively, while 10.0 ± 2.1∘ post-operatively, and 12 ± 3.4∘ at the last follow-up evaluation, respectively. The average VAS score was decreased significantly from 8.7 ± 3.2 pre-operatively to 1.9 ± 0.4 post-operatively. The average ODI score was decreased from 78.3 ± 2.4% pre-operatively to 19.3 ± 5.3% post-operatively. CONCLUSIONS: Anterior column opening structural bone grafting with posterior column compression technique is effective, can effectively restore the sagittal balance of the spine, ease pain, and improve the quality of life of the patients with obsolete vertebral compression fractures and spinal kyphosis.