The accuracy of cortical bone trajectory screw placement guided by spinous process clamp hardware in lumbar spinal surgery: a retrospective study.

This study aimed to assess the accuracy of cortical bone trajectory (CBT) screws placement guided by a spinous process clamp (SPC) guide. A total of 32 patients who received single-level midline lumbar fusion (MIDLF) surgery between June 2019 and January 2020 were retrospectively analyzed and divided into free-hand (FH) and SPC-guided groups according to the surgical approach. In the FH group, CBT screws was implanted with the assistance of fluoroscopy, while in the SPC group, CBT screws was implanted using the SPC navigator hardwire. A total of 128 screws were assessed in this study, with higher rates of clinically acceptable screw placement (grades A and B) and grade A screws in the SPC group than in the FH guide group (92.2% vs. 79.7%, P = 0.042 and 54.7% vs. 35.9%, P = 0.033, respectively). Misplacement screws (grades C, D, and E) occurred more often in the FH group than in the SPC guide group (20.3% vs. 7.8%, P = 0.042). The incidence of proximal facet joint violation (FJV) was higher in the FH group than in the SPC group (15.6% vs. 3.1%, P = 0.030). The radiation dose and time in the SPC guide group were comparable to those in the FH group (P = 0.063 and P = 0.078). The average operative time was significantly longer in the SPC guide group than in the FH group (267.8 ± 45.5 min vs. 210.9 ± 44.5 min, P = 0.001). Other clinical parameters, such as the average bone mineral density (BMD), intraoperative blood loss, and postoperative hospital stay, were not significantly different. Oswestry disability index (ODI) and back pain visual analogue scale (VAS) scores were significantly improved in both groups compared with preoperatively. SPC guided screw placement was more accurate than the fluoroscopy-assisted FH technique for single-level MIDLF at L4/5. Patients undergoing SPC-guided screw placement can achieve similar clinical outcomes as the fluoroscopy-assisted FH technique.

Accuracy of cortical bone trajectory screw fixation guided by spinous process clamp guide in lumbosacral vertebrae: A cadaver study.

BACKGROUND: The purpose of this study was to access the accuracy of cortical bone trajectory screw placement guided by spinous process clamp (SPC). METHODS: Eight formalin-treated cadaveric lumbar specimens with T12-S1 were used. A total of 96 screws were implanted in eight lumbar specimens. RESULTS: In the freehand (FH) group, clinically acceptable placement (grade A and B) was 40 screws (83.3%), meanwhile 44 screws (91.7%) in the SPC guide group (p = 0.217). The grade A screws in the SPC guide group were much more than that in the FH group (n = 40 vs. n = 31, p = 0.036). The misplacement screws (grade C, D, and E) and proximal facet joint violation (FJV) in the SPC group was comparable to the FH group. CONCLUSIONS: This cadaveric study demonstrate that implanting CBT screws guided by SPC guide was more accuracy and reduces severe deviations in important directions.

Cortical screw placement with a spinous process clamp guide: a cadaver study accessing accuracy.

BACKGROUND AND OBJECTIVE: The Cortical Bone Trajectory (CBT) technique provides an alternative method for fixation in the lumbar spine in patients with osteoporosis. An accuracy CBT screw placement could improve mechanical stability and reduce complication rates. PURPOSE: The purpose of this study is to explore the accuracy of cortical screw placement with the application of implanted spinous process clip (SPC) guide. METHODS AND MATERIALS: Four lumbar specimens with T12-S1 were used to access the accuracy of the cortical screw. The SPC-guided planning screws were compared to the actual inserted screws by superimposing the vertebrae and screws preoperative and postoperative CT scans. According to preoperative planning, the SPC guide was adjusted to the appropriate posture to allow the K-wire drilling along the planned trajectory. Pre and postoperative 3D-CT reconstructions was used to evaluate the screw accuracy according to Gertzbein and Robbins classification. Intraclass correlation coefficients (ICCs) and Bland-Altman plots were used to examine SPC-guided agreements for CBT screw placement. RESULTS: A total of 48 screws were documented in the study. Clinically acceptable trajectory (grades A and B) was accessed in 100% of 48 screws in the planning screws group, and 93.8% of 48 screws in the inserted screws group (p = 0.242). The incidence of proximal facet joint violation (FJV) in the planning screws group (2.1%) was comparable to the inserted screws group (6.3%) (p = 0.617). The lateral angle and cranial angle of the planned screws (9.2 ± 1.8° and 22.8 ± 5.6°) were similar to inserted screws (9.1 ± 1.7° and 23.0 ± 5.1°, p = 0.662 and p = 0.760). Reliability evaluated by intraclass correlation coefficients and Bland-Altman showed good consistency in cranial angle and excellent results in lateral angle and distance of screw tip. CONCLUSIONS: Compared with preoperative planning screws and the actually inserted screws, the SPC guide could achieve reliable execution for cortical screw placement.

Preliminary Study of Obese Patients with Chronic Obstructive Pulmonary Disease Suffering from Painful Osteoporotic Vertebral Compression Fracture Treated by Percutaneous Vertebroplasty in Improved Prone Position and Right Lateral Position.

OBJECTIVE: To assess outcomes in obese patients with chronic obstructive pulmonary disease (COPD) who sustained an osteoporotic vertebral compression fracture (OVCF) treated by percutaneous vertebroplasty (PVP) in the improved prone position and right lateral position. METHODS: Between January 2015 and May 2016, a total of 60 patients were enrolled in this randomized controlled study. Patients in group A were placed in the improved prone position for a bilateral transpedicular technique, and those in group B were placed in the right lateral position for a left transverse process-pedicle approach. Clinical and radiologic outcomes were assessed and compared between the 2 groups during the 12-month follow-up period. RESULTS: All operations were successfully completed without any serious sequelae. The operation time, fluoroscopic time, scores for respiratory condition during the operation, intravertebral cement volume, and incidence of cement leakage were significantly greater in group A compared with group B (P < 0.01). During the follow-up period, all patients in both groups experienced significant improvement in pain relief. Satisfactory functional improvement was obtained at 3 months postoperatively. CONCLUSIONS: Treatment of obese patients with COPD suffering from painful OVCF by PVP in both the improved prone position with a bilateral technique and the right lateral position with a unilateral technique was relatively safe and effective. However, unilateral PVP in the right lateral position was associated with a shorter operation time, limited fluoroscopic time, and minimal cement leakage.

Risk factors for pulmonary complications after posterior spinal instrumentation and fusion in the treatment of congenital scoliosis: a case-control study.

BACKGROUND: Although surgery prevents the progression of deformity and maintains the overall balance of the spine in congenital scoliosis (CS) patients, it is associated with a high risk of perioperative complications. Pulmonary complication is one of the most common complications. This retrospective study aimed to investigate the risk factors for pulmonary complications in CS patients after posterior spinal instrumentation and fusion. METHODS: Analysis of consecutive patients who underwent posterior spinal instrumentation and fusion for congenital scoliosis was performed. Preoperative clinical data, intraoperative variables, and perioperative radiographic parameters were collected to analyze the risk factors for pulmonary complications. Patients were separated into groups with and without postoperative pulmonary complications. Potential risk factors were identified by univariate testing. Multivariate logistic regression was used to evaluate independent predictors of pulmonary complications. RESULTS: Three hundred and twenty-three CS patients were included. Forty-five (13.9%) patients developed postoperative pulmonary complications, which included pleural effusion in 34 (75.6%) cases, pneumonia in 24 (53.3%) cases, pneumothorax in 3 (6.7%) cases, atelectasis in 4 (8.9%) cases, pulmonary edema in 2 (4.4%) cases, respiratory failure in 2 (4.4%) cases, and prolonged mechanical ventilation in 4 (8.9%) cases. The independent risk factors for development of pulmonary complications included age (Odds ratio (OR) = 1.088, P = 0.038), reoperation (OR = 5.150, P = 0.012), preoperative pulmonary disease (OR = 10.504, P = 0.004), correction rate (OR = 1.088, P = 0.001), middle thoracic screw-setting (OR = 12.690, P = 0.043), and thoracoplasty (OR = 5.802, P = 0.001). The area under the receiver operating characteristic (ROC) curve based on predicted probability of the logistic regression was 0.903. CONCLUSIONS: Age, reoperation, preoperative pulmonary disease, correction rate, middle thoracic screw-setting, and thoracoplasty were independent risk factors for pulmonary complications after posterior spinal instrumentation and fusion in CS patients.

The Optimal Volume Fraction in Percutaneous Vertebroplasty Evaluated by Pain Relief, Cement Dispersion, and Cement Leakage: A Prospective Cohort Study of 130 Patients with Painful Osteoporotic Vertebral Compression Fracture in the Thoracolumbar Vertebra.

OBJECTIVE: To probe the relationship among cement volume/fraction, imaging features of cement distribution, and pain relief and then to evaluate the optimal volume during percutaneous vertebroplasty. METHODS: From January 2014 to January 2017, a total of 130 patients eligible for inclusion criteria were enrolled in this prospective cohort study. According to the different degrees of pain relief, cement leakage, and cement distribution, all patients were allocated to 2 groups. Clinical and radiologic characteristics were assessed to identify independent factors influencing pain relief, cement leakage, and cement distribution, including age, sex, fracture age, bone mineral density, operation time, fracture level, fracture type, modified semiquantitative severity grade, intravertebral cleft, cortical disruption in the vertebral wall, endplate disruption, type of nutrient foramen, fractured vertebral body volume, intravertebral cement volume, and volume fraction. A receiver operating characteristic curve was used to analyze the diagnostic value of the cement volume/fraction and then to obtain the optional cut-off value. RESULTS: The preoperative visual analog scale scores in the responders versus nonresponders patient groups were 7.37 ± 0.61 versus 7.87 ± 0.92 and the postoperative VAS scores in the responders versus nonresponders were 2.04 ± 0.61 versus 4.33 ± 0.49 at 1 week. There were no independent factors influencing pain relief. There were 95 (73.08%) patients who experienced cement leakage, and cortical disruption in the vertebral wall and cement fraction percentage were identified as independent risk factors by binary logistic regression analysis (adjusted odds ratio [OR] 2.935, 95% confidence interval [95% CI] 1.214-7.092, P = 0.017); (adjusted OR 1.134, 95% CI 1.026-1.254, P = 0.014). The area under the receiver-operating characteristic curve of volume fraction (VF%) was 0.658 (95% CI 0.549-0.768, P = 0.006 < 0.05). The cut-off value of VF% for cement leakage was 21.545%, with a sensitivity of 69.50% and a specificity of 60.00%. The incidence of favorable cement distribution was 74.62% (97/130), and VF% were identified as independent protective factors (adjusted OR 1.185, 95% CI 1.067-1.317, P = 0.002) The area under the receiver-operating characteristic curve of VF% was 0.686 (95% CI 0.571-0.802, P = 0.001 < 0.05). The cut-off value of VF% to reach a favorable cement distribution was 19.78%, with a sensitivity of 86.60% and a specificity of 51.50%. CONCLUSIONS: In osteoporotic vertebral compression fracture with mild/moderate fracture severity at the single thoracolumbar level, the intravertebral cement volume of 4-6 mL could relieve pain rapidly. The optimal VF% was 19.78%, which could achieve satisfactory cement distribution. With the increase of VF%, the incidence of cement leakage would also increase.

Interspinous dynamic stabilization adjacent to fusion versus double-segment fusion for treatment of lumbar degenerative disease with a minimum follow-up of three years.

PURPOSE: The aim of this study was to assess the outcome of symptomatic lumbar degenerative disease treated with topping-off technique (Coflex(™) combined with fusion) and compare two-segment fusion at mid-long term follow-up; and find out whether the topping-off technique can reduce the rate of adjacent segment degeneration (ASD) after fusion. METHODS: One hundred and fifty-four consecutive patients who received topping-off surgery (76 patients) and two-segment fusion surgery (88 patients) from March 2009 to March 2012 were studied. All patients included in the analysis had a minimum of three years of follow-up. Radiographic and clinical outcomes between the two groups were compared. A logistic regression analysis was used to analyze risk factors for developing radiographic ASD. RESULTS: Significant differences in clinical outcomes were observed between these two groups at three post-operative years (all, p < 0.05). Compared with the fusion group, the topping-off group showed preserved mobility at the Coflex(™) level (p = 0.000), which is associated with less blood loss (p = 0.000), shorter duration of surgery (p = 0.000) and lower incidence of ASD (Chi-square test, rate topping-off vs fusion = 13.2 vs 26.1 %, p = 0.039). There were no differences in complications between the two groups. CONCLUSION: Mid-long term follow-up efficacy and safety between topping-off and fusion were similar, while topping-off reduced the rate of ASD. Under strict indications, topping-off surgery is an acceptable alternative to fusion surgery for the treatment of two-segment lumbar disease.

[Relationship between low back pain and lumbar sagittal alignment after lumbar fusion].

OBJECTIVE: To evaluate retrospectively the relationship between low back pain and changes of lumbar spine sagittal alignment after lumbar spine fusion. METHODS: During January-December 2008, a total of 182 consecutive patients with degenerative lumbar spine diseases underwent posterior lumbar interbody fusion (PLIF) and the follow-up period was over 24 months. Standing lumbar spine anteroposterior and lateral radiography were taken during the follow-up and the lumbar lordosis Cobb angles were measured on radiography. Pain degrees were assessed by visual analog scale (VAS) and Oswestry disability index (ODI). The relationship between the changes of Cobb angle and lumbar sagittal plane curve was analyzed by the SPSS software. Also the relationship between back pain degree and Cobb angle was examined. RESULTS: Among them, 42 cases with postoperative back pain were followed up for 24 months. There were 19 males and 23 females with a mean age of 59.6 years (range: 40 - 77). Lumbar spine sagittal Cobb angles were measured from radiographic images:lumbar lordosis angle: (1) mean angle at 12-month follow-up: 40.1° ± 10.6°, range: 20° - 60°; (2) mean angle at 24-month follow-up: 40.8° ± 10°, range: 24° - 60°. Back pain of 42 patients: VAS: (1) mean at 12-month follow-up: 29.4 ± 11.5, range: 5 - 50; (2) mean at 24-month follow-up: 27.6 ± 11.7, range: 25 - 48. Lumbar spine function of 42 patients: ODI: (1) mean at 12-month follow-up: 15.1 ± 5.4, range: 0 - 25; (2) mean at 24-month follow-up: 13.9 ± 5.2, range: 0 - 24. Difference between lumbar lordosis angle and standard score: (1) mean angle at 12-month follow-up: 19.9° ± 10.6°, range:0°-40°; (2) mean angle at 24-month follow-up:19.2° ± 10.0°, range:0°-36°. Angle difference versus back pain VAS: (1) at 12-month follow-up:P < 0.001, positive correlation; (2) 24-month follow-up: P < 0.001, positive correlation; angle difference versus back pain ODI: (1) 12-month follow-up:P < 0.001, positive correlation; (2) 24-month follow-up: P < 0.001, positive correlation. CONCLUSION: There is a close relationship between back pain after fusion and loss of lumbar sagittal lordosis. And reconstruction of lumbar lordosis should be one important goal for lumbar fusion.

Three-fin acetabular prosthesis for superior acetabular bone defects: a three-dimensional finite element analysis.

BACKGROUND: Given that three-dimensional finite element models have been successfully used to analyze biomechanics in orthopedics-related research, this study aimed to establish a finite element model of the pelvic bone and three-fin acetabular component and evaluate biomechanical changes in this model after implantation of a three-fin acetabular prosthesis in a superior segmental bone defect of the acetabulum. METHODS: In this study, three-dimensional finite element models of the pelvic bone and three-fin acetabular component were first established. The prosthesis model was characterized by three different conformational fins to facilitate and optimize the prosthetic design. The spongy and cortical bones were evaluated using a different modulus of elasticity in this established model. RESULTS: The maximum and minimum von Mises stresses on the fins of the acetabular component were 15.2 and 0.74, respectively. The maximum and minimum micromotion between the three-fin acetabular component and the acetabulum bone interface were 27 and 13 µm, respectively. A high primary stability and implied better clinical outcome were revealed. CONCLUSION: Finite element analysis may be an optimal strategy for biomechanics-related research of prosthetic design for segmental acetabular bone defects.

[Kyphoplasty for treatment of non-osteoporotic thoracolumbar compressive fractures: analysis of 17 cases].

OBJECTIVE: To evaluate the efficacy and safety of kyphoplasty for treatment of non-osteoporotic compressive fractures of thoracolumbar vertebrae. METHODS: Seven patients of non-osteoporotic thoracolumbar compressive fractures confirmed by plain X-ray examination and CT scanning, 14 males and 3 females, aged 35.2, all suffering from one level fracture, at T9 in 1 case, T11 in 2 cases, T12 in 7 cases, L1 in 5 cases, L2 in 1 case, and L3 in 1 case were. treated with percutaneous kyphoplasty. Under local anesthesia Kypho-X vertebra expander was inserted into the vertebral body and polymethylmethacrylate (PMMA) bone cement was filled. Then the patients were followed up for 6 months (6-24 months) by using the visual analog scale, Oswestry disability index (ODI), and the vertebra height and kyphosis were analyzed. RESULTS: All patients underwent the procedure safely. Except for two cases with complication of para-vertebra cement leakage no other complication occurred. The average surgery time was 55 min. All patients became able to get up of bed 2 days and discharged 7 days postoperatively and continued to be protected by hard prosthesis for two weeks more. The average score of VAS was 8.7 before the operation, and then gradually decreased, to 3.2 and 2.7 1 and 4 weeks postoperatively, and became 2.1 at the last follow-up (all P < 0.05). The average ODI score was 72.3 before the operation, and then gradually decreased to 48.6 and 28.9 1 week and 4 weeks postoperatively, and became 22.4 at the last follow-up (all P < 0.05). The average height of the vertebra was 14.3 mm preoperatively, and increased to 24.7 mm 1 week postoperative and 22.4 mm at the last follow up (both P < 0.05). The kyphosis of the fractured vertebra was 31.1 degrees preoperatively and decreased to 9.6 degrees 1 week postoperatively and 10.9 degrees at the last follow up (both P < 0.05). All patients returned to their previous work and life within 2 months postoperatively. CONCLUSION: Percutaneous kyphoplasty is effective and safe in the treatment of non-osteoporotic thoracolumbar compressive fractures with the advantages of minimum invasiveness, fast pain relief and recovery, as well as restoration of vertebra height and correction of kyphosis.