Will coronal alignment postoperatively be deteriorating in adult spinal deformity after long-fusion surgery?

BACKGROUND: To investigate whether the coronal alignment (CA) will deteriorate, and identify the risk factors for coronal malalignment (CM) developing in adult spinal deformity (ASD) after long-fusion surgery. METHODS: A multi-center retrospective study was performed, which included a total of 161 ASD patients who had undergone the surgical procedure of long-fusion (≥ 5 vertebras) with instrumentations in three medical centers. All of the participants were retrospectively reviewed, and subsequently assigned into the consistency group (C7 plumb line (C7PL) shifting towards the convex side of the main curve), and the opposition group (C7PL shifting towards the concave side). CM was considered if the coronal balance distance (CBD) being over 30 mm. A Kaplan-Meier curve and log-rank test were used to analyze the differences in CM-free survival during follow-up. Multivariate analysis via a Cox proportional hazards test was used to analyze the risk factors. RESULTS: Patients showing CM equaled 35 (21.7%) at the pre-operation, and that increased significantly up to 51 (31.7%) at the final follow-up (P = 0.04). In the consistency group, the incidence of CM at the final follow-up was much higher than that preoperatively (35:16, P = 0.002). CM-free survival time decreased significantly in patients with larger CBD correction, pelvic fixation and more instrumented segments, respectively, during follow-up (P < 0.05, log-rank test). Age ≥ 60 years, the consistency CA, pelvic fixation, CBD-correction ≥ 30 mm and fixed-vertebra ≥ 8 were risk factors for CM happening after surgery using multivariate regression analysis (P < 0.05). CONCLUSIONS: The coronal alignments in ASD patients underwent long-fusion surgeries may deteriorate during follow-up, for which the risk factors include the consistency CA, age ≥ 60, fixed-vertebra ≥ 8, CBD-correction ≥ 30 mm and pelvic fixation.

Correlation between Disc Imaging Observations and Clinical Efficacy after Percutaneous Endoscopic Lumbar Discectomy: A 1-Year Follow-up Study.

OBJECTIVE: The connection between alterations in the disc structure following percutaneous endoscopic lumbar discectomy (PELD) and symptoms in patients postsurgery has not been reported yet. The purpose of the present study was to discuss the potential correlation between the changes in the morphological characteristics of various reference surfaces of the intervertebral disc after percutaneous endoscopic lumbar discectomy (PELD) and clinical outcomes, to identify the morphological parameters that affect efficacy and provide an evidence-based foundation for assessing postoperative efficacy. METHODS: From October 2019 to October 2021, after percutaneous endoscopic lumbar discectomy (PELD), 98 individuals were enrolled. MRI DICOM data of the lumbar spine were obtained before and after surgery, specifically around 3 months. The morphological parameters of the operated and adjacent segments of the discs were measured using T2-weighted images from three reference planes. Outcomes were assessed using the Oswestry disability index (ODI), visual analogue pain scores for the back and leg (VAS-back/VAS-leg), Japanese Orthopaedic Association (JOA) scores, and recovery rates. Postoperative changes in disc parameters and outcomes were compared between patients with different severity and types of LDH based on the MSU staging. Patients completed the questionnaire during outpatient follow-up appointments 3, 6, and 12 months after the surgery. The follow-up period was 14.69 ± 4.21 months, ranging from 12 to 24 months. RESULTS: Parameters such as area and circumference of intervertebral discs in the cross-section were not associated with the change in the efficacy index. Postoperatively, a negative correlation between the variation of the disc height, disc height index, and protrusion distance and the difference in VAS scores for low back pain at 3 and 6 months was observed among the two sagittal change parameters. Differences between changes in disc imaging parameters and postoperative efficacy were not statistically significant between various types of lumbar disc herniation. CONCLUSION: For the patients after percutaneous endoscopic lumbar discectomy, the changes in parameters such as disc area and circumference in the cross-sectional plane are not associated with efficacy, and the changes in disc height and herniation distance in the sagittal plane provide a morphologic basis for the assessment of short-term postoperative efficacy. In addition, the changes in disc morphologic parameters and postoperative efficacy do not differ between various types of lumbar disc herniation.

How does the correction in lumbar lordosis affect the spinopelvic realignments in degenerative lumbar scoliosis underwent scoliosis surgery?

BACKGROUND: To evaluate the effects of correction in lumbar lordosis (LL) that have on full-body realignments in patients with degenerative lumbar scoliosis (DLS) who had undergone long sacroiliac fusion surgery. METHODS: A multi-center retrospective study including 88 DLS patients underwent the surgical procedure of long sacroiliac fusion with instrumentations was performed. Comparisons of radiographic and quality-of-life (QoL) data among that at the pre-operation, the 3rd month and the final follow-up were performed. The correlations between the LL correction and the changes in other spinopelvic parameters were explored using Pearson-correlation linear analysis and linear regression analysis. The correlation coefficient (r) and the adjusted r2 were calculated subsequently. RESULTS: All radiographic and QoL data improved significantly (P < 0.001) after the surgical treatments. The LL correction correlated (P < 0.001) with the changes in the sacral slope (SS, r = 0.698), pelvic tilt (PT, r = -0.635), sagittal vertical axis (SVA, r = -0.591), T1 pelvic angle (TPA, r = -0.782), and the mismatch of pelvic incidence minus lumbar lordosis (PI-LL, r = -0.936), respectively. Moreover, LL increased by 1° for each of the following spinopelvic parameter changes (P < 0.001): 2.62° for SS (r2 = 0.488), -4.01° for PT (r2 = 0.404), -4.86° for TPA (r2 = 0.612), -2.08° for the PI-LL (r2 = 0.876) and -15.74 mm for SVA (r2 = 0.349). Changes in the thoracic kyphosis (r = 0.259) and pelvic femur angle (r = 0.12) were independent of the LL correction, respectively. CONCLUSIONS: LL correction correlated significantly to the changes in spinopelvic parameters; however, those independent variables including the thoracic spine and hip variables probably be remodeled themselves to maintain the full-body balance in DLS patients underwent the correction surgery.

Trans-intervertebral osteotomy classification of posterior spinal corrective osteotomy procedures via the intervertebral space.

•This is a diagnostic study for a classification for posterior spinal osteotomy procedures via the intervertebral space.•Proposed â€‹a novel classification â€‹with â€‹excellent reliability â€‹and â€‹validity, differ from the SRS-Schwab osteotomy classification.•Give a novel definition of "trans-intervertebral osteotomy" (TIO) for posterior spinal osteotomy procedures.•Thoroughly discussed about the histories of posterior spinal osteotomy procedures via the intervertebral space.•Systematically introduced the TIO technique with fine original schematics.

Clinical Results of Utilizing the Satellite Rod Technique in Treating Ankylosing Spondylitis Kyphosis.

OBJECTIVE: According to the literature, there are no clinical reports documenting the use of the satellite rod technique in the treatment of ankylosing spondylitis kyphosis. The purpose of this retrospective study was to compare the clinical outcome of patients with ankylosing spondylitis kyphosis who adopted satellite rods versus those who did not. METHODS: Patients with ankylosing spondylitis kyphosis who underwent one or two-level pedicle subtraction osteotomy (PSO) were reviewed, and total of 119 patients (112 males and seven females, average age 39.89 ± 6.61 years) were eligible and included in this present study. Anterior-posterior and lateral full-length spine X-ray films were performed preoperatively and at the two-year follow-up visit. Global kyphosis (GK), lumbar lordosis (LL), thoracolumbar kyphosis (TLK), thoracic kyphosis (TK), and osteotomy angle (OA) were measured. The complications of every group of patients were collected. Pre- and postoperative health-related quality of life instruments, including the Bath Ankylosing Spondylitis Functional Index (Basfi) and Scoliosis Research Society outcomes instrument-22 (SRS-22), were recorded. The patients were divided into three groups based on features of their osteotomy including PSO levels and whether the satellite rod technique was applied. Patients who underwent one-level PSO without the satellite rod technique were categorized in the one-level group. Patients who underwent one-level PSO with the satellite rod technique were classified in the satellite rod group. Patients who underwent two-level PSO without the satellite rod technique were included in the two-level group. The paired sample t test was used to compare pre- and postoperative parameters. One-way ANOVA was performed for multiple group comparisons. RESULTS: The average follow-up time is 29.31 ± 3.66 months. The patients' GK were significantly improved from 46.84 ± 20.37 degree to 3.31 ± 15.09 degree. OS achieved through each osteotomy segment of one-level group (39.78 ± 12.29 degree) and satellite rods group (42.23 ± 9.82 degree), was larger than that of two-level group (34.73 ± 7.54 and 28.85 ± 7.26 degree). There was no significant difference between the one-level group and the satellite rod group in achieving the OS. Thirteen patients experienced different complications (10.92%). Three patients experienced rod fracture in the one-level group. There was no rod fracture or screw failure in the satellite rod group or the two-level group. CONCLUSION: The satellite rod technique is also recommended for patients who undergo PSO osteotomy to correct ankylosing spondylitis kyphosis deformities.

Factors Related to Preoperative Coronal Malalignment in Degenerative Lumbar Scoliosis: An Analysis on Coronal Parameters.

OBJECTIVES: Recently the effects of coronal malalignment (CM) in degenerative lumbar scoliosis (DLS) have been reported, however, there was few studies on the correlated parameters of coronal alignments at pre-operation. The aims of this current study were to investigate the associations of coronal parameters with scoliosis and coronal alignment, and to explore the relationships between the coronal pelvic tilt and coronal alignment in DLS. METHODS: One hundred and sixty-one DLS patients in our hospital from May 2016 to December 2020 were reviewed and documented. The coronal balance distance (CBD, the offset between the center of C7 and the plumb line drawn from the center of S1), major Cobb (MC), fractional Cobb (FC), L4 coronal tilt, L5 coronal tilt, coronal pelvic tilt, apical rotation, and the vertebras in major curve were measured and documented. CM was considered if the CBD ≥ 30mm. All of those participants were assigned into group A (CBD ≥ 30 mm) and group B (CBD < 30 mm). Comparisons of demographic and radiographic data were performed between groups A and B. Pearson correlation and further multiple regression with stepwise method analysis were used to investigate those coronal parameters correlated to MC and CBD, respectively. RESULTS: Thirty-one patients suffering from CM were assigned into group A, and the rest of 130 patients were assigned to group B accordingly. Then the incidence of CM was about 19.3% (31/161). Patients in group A had less vertebras in the main curve (P = 0.009), however, the apical rotation (P < 0.001) and the L4 coronal tilt (P = 0.007) were much larger. Although the MC (P = 0.426) and FC (P = 0.06) had no difference between the two groups, the match between MC and FC was much smaller (p = 0.021) in group A. The coronal pelvic tilt correlated significantly with FC (r = 0.552, p < 0.001), but mildly with MC (r = -0.366, p < 0.001), L4 coronal tilt (r = 0.348, p < 0.001), and L5 coronal tilt (r = 0.351, p < 0.001), respectively. The CBD correlated strongly with L4 coronal tilt (r = -0.471, p < 0.001) and L5 coronal tilt (r = -0.468, p < 0.001), respectively, but mildly with FC (r = -0.255, p = 0.016). Further multiple regression analysis revealed that only L4 coronal tilt was the independent factor for MC (r2  = 0.549, p < 0.001) and CBD (r2  = 0.221, p < 0.001), respectively. CONCLUSIONS: The prevalence of CM in DLS patients is about 19% at pre-operation. With similar major Cobb, the less the vertebras in the major curve, the larger the CBD. L4 coronal tilt may correlate significantly to scoliosis and CBD. Coronal pelvic tilt may be just one of the compensations for the scoliosis deformity but effects CBD directly.

Pedicle Subtraction Osteotomy in Lateral Position: A New Strategy for Correcting Severe Thoracolumbar Kyphosis Combined with Hip Flexion Contracture in Ankylosing Spondylitis.

OBJECTIVE: To describe spinal osteotomy in lateral position, which might be a new strategy for correcting thoracolumbar kyphotic deformity combined with severe hip flexion contracture, and to present two cases in which this method was successfully performed. METHODS: Spinal osteotomies in lateral position were performed in two patients with severe thoracolumbar kyphosis combined with hip flexion contracture, which was not suitable for operation in the prone position. Case 1: a 33-year-old female AS patient still had severe hip flexion contracture due to poor rehabilitation after total hip replacement (THR). The range of movement of the hip was only about 15° in right and 10° in left. Pre-operativethoracic kyphosis (TK), thoracolumbar kyphosis (TLK), lumbar lordosis (LL), and sagittal vertical axis (SVA) were 52.4°, 49.1°, 42.7°, and 315 mm, respectively. Pedicle subtraction osteotomy (PSO) at L3 was performed in the lateral position. The eggshell procedure was used during osteotomy. Case 2: a 45-year-old male AS patient presented coexisting rigid thoracolumbar kyphosis and hip flexion contracture. The range of movement of the hip was only about 20° in right and 25° in left. Pre-operativeTK, TLK, LL and SVA were 34.9°, 66.8°, 58.8° and 290.8 mm, respectively. PSO at L2 was performed in lateral position. The eggshell procedure was also used. RESULTS: Sagittal malalignments of both patients were greatly improved. For case 1, the total operation time was 5.5 h. The blood loss was 1500 mL and the amount of allogeneic blood transfusion was 1580 mL during the operation. SVA was reduced to 127 mm and LL decreased from preoperative 42.7° to -28.4°. The correction angle through L3 was 34.7° and the correction angle through the osteotomy segment was 62.9°. For case 2, the duration of surgery was 6.5 h. The operative blood loss was 2000 mL and the total amount of blood transfusion was 2020 mL. SVA was reduced to 209.8 mm and LL decreased from preoperative 58.8° to 9.2°.The correction angle through L2 was 37.1° and the correction angle through the osteotomy segment was 55°. No intra-operative or post-operative complications were observed. Six months after PSO, case 1 had good posture for standing and sitting. The case 2 underwent bilateral THRs nine months after PSO. CONCLUSION: PSO could be performed in the lateral position successfully. For AS patients who cannot be placed in the prone position due to coexisting severe thoracolumbar kyphosis and hip flexion contracture, performing spinal osteotomy in the lateral position as the first step is an alternative.

Correlation of Acetabular Anteversion and Thoracic Kyphosis Postoperatively with Proximal Junctional Failure in Adult Spinal Deformity Fused to Pelvis.

OBJECTIVES: To investigate whether the immediate thoracic kyphosis (TK) and acetabular anteversion (AA) postoperatively are correlated with proximal junctional failure (PJF) in adult spinal deformity (ASD) patients underwent surgical treatment. METHODS: This is a retrospective study. Following institutional ethics approval, a total of 57 patients (49 Female, eight Male) with ASD underwent surgery fused to sacroiliac bone (S1, S2, or ilium) from March 2014 to January 2019 were included. All of those patients were followed up for at least 2 years. Demographic, radiographic and surgical data were recorded. The maximum range of flexion motion (F-ROM) and extension motion (E-ROM) actively of hip joints was measured and recorded at pre- and postoperation. The sum of F-ROM and E-ROM was defined as the range of hip motion (H-ROM). Receiver operating characteristic (ROC) curve analysis was used to obtain the cut off value of parameters for PJF. A Kaplan-Meier curve and log-rank test were used to analyze the differences in PJF-free survival. RESULTS: In all, 14 patients developed PJF during follow-up. Comparisons between patients with and without PJF showed significant differences in immediate TK (P < 0.001) and AA (P = 0.027) postoperatively. ROC curve analysis determined an optimal threshold of 13° for immediate AA postoperatively (sensitivity = 74.3%, specificity = 85.7%, area under the ROC curve [AUC] = 0.806, 95% CI [0.686-0.926]). Nineteen patients with post-AA ≤13° were assigned into the observational group, and 38 patients with post-AA >13° were being as the control group. Patients in the observational group had smaller H-ROM (P = 0.016) and F-ROM (P < 0.001), but much larger E-ROM (P < 0.001). There were 10 patients showing PJF in the observational group and four in the control group (10/9 vs 4/34, P < 0.001). PJF-free survival time significantly decreased in the observational group (P = 0.001, log-rank test). Furthermore, patients in the observational group had much larger TK (post-TK, P = 0.015). The optimal threshold for post-TK (sensitivity = 85.7%, specificity = 76.7%; AUC = 0.823, 95% CI [0.672-0.974]) was 28.1° after the ROC curve was analyzed. In the observational group, those patients with post-TK ≥28.1° had significantly higher incidence of PJF (9/2 vs 1/7, P < 0.001) than those with post-TK < 28.1°. Moreover, PJF-free survival time in those patients significantly decreased (P = 0.001, log-rank test). CONCLUSIONS: ASD patients with acetabular anteversion of ≤13° at early postoperation may suffer significantly restricted hip motion and much higher incidence of PJF during follow-up, moreover, in those patients, postoperative TK ≥28.1° would be a significant risk factor for PJF developing.

Association of Sagittal Spinopelvic Realignment with Correction in Lower Lumbar Lordosis after Surgical Treatment in Degenerative Lumbar Scoliosis.

OBJECTIVE: To assess the effect that correction of lower lumbar lordosis (3L) has on global spine realignment due to the key role of 3L for scoliosis surgery in patients with degenerative lumbar scoliosis (DLS). METHODS: This study is a retrospective review performed between June 2018 and January 2020, including consecutive patients with DLS. Only patients age ≥ 45 years who had already undergone a selective root block operation and had the procedure of long-fusion extending to pelvis and posterior lumbar interbody fusion (PLIF) at lower lumbar spine (L4 -S1 ) were retained for analysis. Spinopelvic parameters measured included thoracic kyphosis (TK), lumbar lordosis (LL), 3L, pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), T1 pelvic angle (TPA), and sagittal vertical axis (SVA) at pre-operation and the third month follow-up. The mismatch (PI-LL) was calculated subsequently. Pearson correlation and linear regression analysis were performed to explore the association of the changes in global spinopelvic parameters with 3L correction. RESULTS: Thirty-nine patients (five males, 34 females) with the average age of 63.84 years (SD 7.53; range, 45-75 years) at the time of surgery were identified. All patients had the surgical procedure of long-fusion (≥4 vertebras) with PLIF at lower lumbar spine between L4 and S1 spine. Lower instrumented vertebras (LIV) fused to pelvis (S1 , 14; S2 , 18; ilium, 7) were operated in all patients. Seventeen patients were with upper instrumented vertebras (UIV) at thoracolumbar spine (L2 -T11 ), and 22 patients at thoracic spine (T10 and above). The median of instrumented segments was 10 (5-14). 3L significantly increased (P = 0.02) after surgical treatment by mean change of 4.21° (range, -19.7° to +22.2°). Perioperatively, all spinopelvic parameters regarding to TK, LL, SS, PT, TPA, SVA, and mismatch (PI-LL) had significant changes (P < 0.001). The change in 3L correlated significantly with the changes in spinopelvic parameters (r = 0.772 for LL, -0.589 for SVA, -0.439 for TPA, and -0.428 for PI-LL). After linear regression analysis, the formulas were obtained: d-LL = 14.977 + 0.636 × d-3L, (R2 = 0.596); d-(PI-LL) = 16.575 + 0.62 × d-3L, (R2 = 0.183); d-TPA = -7.284 to 0.358 × d-3L, (R2 = 0.193); d-SVA = -30.556-2.639 × d-3L (R2 = 0.347). CONCLUSIONS: Correction in lower lumbar lordosis, following the surgical procedure of long-fusion with PLIF at lower lumbar spine, could result in significant changes in full-spine parameters. The significant association of changes in each of global spine parameter with the correction of 3L perioperatively could provide important information for surgeons to make a surgical plan for spinal correction.

Transpedicular bi-vertebrae wedge osteotomy in treatment of post-tubercular spinal deformity: a retrospective study.

BACKGROUND: In the late stage of spinal tuberculosis, the bony destruction and vertebral collapse often leads to significant kyphosis, presenting clinically as a painful gibbus deformity, with increased instability, vertebral body translations and increased risk of neurologic involvement. Spinal osteotomy is thought to be suitable for most patients with severe rigid kyphosis. The aim of this study was to evaluate the efficacy of transpedicular bi-vertebrae osteotomy technique in the patients with Pott's kyphosis and other post-tubercular spinal deformity. METHODS: Between January 2012 and December 2015, 18 patients with post-tubercular spinal deformity underwent the transpedicular bi-vertebrae wedge osteotomy, with a minimum follow up of 27.0 months. Preoperative and postoperative kyphotic angle, sagittal plane parameters (TK for thoracic deformity, TLK for thoracolumbar and LL for lumbar deformity) and sagittal vertical axis (SVA) were measured. Oswestry Disability Index (ODI), Visual analog scale (VAS) and modified American Spinal Injury Association grading (ASIA) of preoperative and final follow-up were documented and compared. RESULTS: The average operation time was 305 minutes (range, 200-430 minutes) with a mean intraoperative blood loss of 425 mL (range, 200-700 mL). The kyphotic angles decreased from 80.3° (range, 28.5°-130.8°) preoperatively to 26.1° (range, 7.0°-63.3°) at the final follow-up (P<0.01). The mean VAS score was reduced from preoperative 5.2(range, 2-9) to 0.9(range, 0-2, P<0.01) and the ODI improved from 55.3% (range, 46%-76%) to 6.3% (range, 2%-18%, P<0.01). At final follow-up, there was radiographic evidence of solid fusion at the osteotomy site and fixed segments in all patients. Neurological function improved from ASIA scale D to E in 7 patients, C to D in 3 patients. CONCLUSIONS: Our results suggest that transpedicular bi-vertebrae wedge osteotomy is a safe and effective treatment option for post-tubercular spinal deformity. This technique achieves satisfying correction and fusion rates with adequate decompression of neurological elements.

Compensatory Mechanism of Maintaining the Sagittal Balance in Degenerative Lumbar Scoliosis Patients with Different Pelvic Incidence.

OBJECTIVE: To investigate the compensatory mechanism of maintaining the sagittal balance in degenerative lumbar scoliosis patients with different pelvic incidence (PI). METHODS: This was a retrospective imaging observation study. Patients in our department with degenerative lumbar scoliosis between 2017 and 2019 were reviewed. A total of 36 patients were eligible and included in the present study. The average age of those patients was 64.22 years, including 8 men and 28 women. The coronal and sagittal parameters were measured on full-length spine X-ray film, including globe kyphosis (GK), lumber lordosis (LL), thoracolumbar kyphosis (TLK), thoracic kyphosis (TK), sagittal vertical axis (SVA), sagittal shift angle, Cobb angle, coronal shift angle, and vertebra. The anterior pelvic plane angle (APPA) and pelvic parameters were also measured, including the pelvic tilt (PT), the PI, and the sacral slope (SS). PI-LL, LL-SS, and GK-SS were calculated. Traditional pelvic tilt was also calculated using the following formula: cPT = PI × 0.37-7. These patients were divided into two groups according to their PI values. The patients' PI value in Group 1 was smaller than 50°. The patients' PI value in Group 2 was equal to or larger than 50°. RESULTS: These patients' SS, PT, PI, LL, TLK, TK, and GK were 28.70° ± 11.36°, 23.28° ± 6.55°, 52.00° ± 11.03°, 31.66° ± 14.12°, 12.12° ± 14.9°, 17.81° ± 13.53°, and -13.17° ± 16.27°. The sagittal shift angle, the APPA, the Cobb angle, the coronal shift angle, vertebra, PI-LL, cPT, APPA-4, LL-SS, and GK-SS were 4.38° ± 5.75°, -12.55° ± 8.83°, 30.03° ± 12.59°, 2.40° ± 2.13°, 4.08 ± 0.93, 19.86° ± 10.97°, 12.35° ± 4.55°, -8.30° ± 9.07°, 3.30° ± 8.82°, and 15.53° ± 9.83°, respectively. There was no significant difference between PT and cPT + APPA-4 or between cPT and PT-APPA+4. There was significant difference between PT and cPT + APPA or between cPT and PT-APPA. This demonstrated that the APPA-4 is reliable as degree of the pelvic sagittal retroversion. There were significant differences in SS, PI, LL, TLK, GK, APPA, PT-APPA, PT-APPA+4, cPT, and APPA-4 between Group 1 and Group 2. There were no significant differences in PT, TK, sagittal shift angle, SVA, Cobb angle, coronal shift angle, vertebra number, PI-LL, cPT + APPA, cPT + APPA-4, LL-SS, and GK-SS between Group 1 and Group 2. The Pearson tests showed that PI-LL had significant correlations with TK, LL, sagittal shift angle, SVA, and LL-SS. There was no significant correlation between PI-LL and Cobb angle, GK, TLK, APPA, vertebra, Coronal Shift Angle, or GK-SS. CONCLUSION: The APPA-4 is reliable as degree of the pelvic sagittal retroversion. In degenerative lumbar scoliosis, patients with smaller PI tended to rely more on the pelvic retroversion to maintain the sagittal balance than patients with larger PI, or patients with smaller PI were likely to start up the pelvic retroversion compensatory mechanism earlier than the patients with larger PI.

Asymmetrical vertebral column decancellation for the management of rigid congenital kyphoscoliosis.

BACKGROUND: Congenital kyphoscoliosis is a disease that often requires surgical treatment. Wedge osteotomies, such as pedicle subtraction osteotomy, are insufficient to correct this complicated rigid deformity. Vertebral column resection yields sufficient correction, but it is an exhaustively lengthy operation with a high risk of major complications. There are few effective and safe techniques for treating rigid congenital kyphoscoliosis. We aimed to investigate the technique of asymmetrical vertebral column decancellation (AVCD) for the treatment of rigid congenital kyphoscoliosis and evaluate the clinical and radiographic results of patients treated with the technique. METHODS: Between January 2013 to June 2017, the data of 31 patients with congenital kyphoscoliosis who underwent single level AVCD were reviewed. Preoperative and postoperative radiographical parameters and the visual analogue scale, Asia Spinal Injury Association, and Scoliosis Research Society-22 scores were documented. The patients were followed up for an average period of 29 months. RESULTS: The average operative time was 273.9 ± 46.1 min. The average volume of blood loss was 782.3 ± 162.6 ml. The main coronal curve improved from a mean of 81.4° preoperatively to 24.7° at the final follow-up, and the coronal balance improved from 28.9 to 7.6 mm. The degree of local kyphosis improved from a mean of 86.5° to 29.2°, and the sagittal balance improved from 72.3 to 16.9 mm. All clinical outcomes also improved significantly from preoperatively to the final follow-up. No permanent postoperative neurologic complications occurred. CONCLUSION: The AVCD surgical procedure corrects spinal deformities in both the coronal and sagittal planes by way of a convex-sided Y shape osteotomy, achieves satisfactory realignment without additional neurological complications, and can be considered an alternative treatment for rigid congenital kyphoscoliosis.

Relationship between postoperative lordosis distribution index and adjacent segment disease following L4-S1 posterior lumbar interbody fusion.

BACKGROUND: Adjacent segment disease (ASD) is an acknowledged problem of posterior lumbar interbody fusion (PLIF). Many studies have been reported concerning the role of lordosis distribution index (LDI) in spinal biomechanics. However, few reports have been published about the impact of LDI on ASD following L4-S1 PLIF. METHODS: The study enrolled 200 subjects who underwent L4-S1 PLIF for degenerative spine disease from 2009 to 2014. The average follow-up term was 84 months. Several lower lumbar parameters were measured, including lower lumbar lordosis (LLL), lumbar lordosis (LL), pelvic incidence (PI), and LDI on the pre and postoperative radiograph. Perioperative information, comorbidities, and operative data were documented. Kaplan-Meier curves were plotted for the comparisons of ASD-free survival of 3 different types of postoperative LDI subgroups. RESULTS: The incidence of ASD was found to be 8.5%. LL and LLL increased by 3.96° (38.71° vs 42.67°; P < 0.001) and 3.60° (26.22° vs 28.82°; P < 0.001) after lower lumbar fusion surgery, respectively. Lordosis distribution index (LDI) increased by 0.03 (0.66 vs 0.69, P = 0.004) postoperatively. A significant difference (P = 0.001) was observed when comparing the incidence of ASD among postoperative LDI subgroups. The Kaplan-Meier curves showed a marked difference in ASD-free survival between low and moderate LDI subgroup (log-rank test, P = 0.0012) and high and moderate LDI subgroup (log-rank test, P = 0.0005). CONCLUSION: Patients with abnormal postoperative LDI were statistically more likely to develop ASD than those who had normal postoperative LDI. Moreover, patients with low postoperative LDI were at greater risk for developing ASD than those with high postoperative LDI over time.

Increasing pelvic incidence is associated with more global sagittal imbalance in ankylosing spondylitis with thoracolumbar kyphosis: an observational retrospective study of 94 cases.

BACKGROUND: Ankylosing spondylitis (AS) patients with kyphosis have an abnormal spinopelvic alignment and pelvic morphology. Most studies focus on the relationship of pelvic tilt (PT) or sacral slope (SS) and deformity, and relatively few studies have addressed the relationship between pelvic incidence (PI) and kyphosis in AS patients. The purpose of this study is to analyze the correlation between pelvic incidence (PI) and the spinopelvic parameters describing local deformity or global sagittal balance in AS patients with thoracolumbar kyphosis. METHODS: A total of 94 patients with AS (91 males and 3 females) and 30 controls (27 males and 3 females) were reviewed. The mean age was 36.8 years in AS patients and 34.4 years in controls. Gender ratios and mean age were similar in both group. Sagittal spinopelvic parameters, including PI, PT, SS, thoracic kyphosis (TK), thoracolumbar kyphosis (TLK), lumbar lordosis (LL), sagittal vertical axis (SVA), the first thoracic vertebra pelvic angle (TPA), spinosacral angle (SSA) and spinopelvic angle (SPA) were measured. The same spine surgeons measured all the parameters of the AS and control group. All the sagittal spinopelvic parameters were compared between the groups. The relationship between PI and other spinopelvic parameters was analyzed with Pearson correlation (r) and unary linear regression model. RESULTS: All the sagittal parameters were found to be significantly different between AS patients and controls. Compared with the control group, the AS patients had significantly higher PI(47.4° vs. 43.2°, P < 0.001). Correlation analysis revealed that PI in AS patients was significantly positively correlated with TPA(r = 0.533, R2 = 0.284, P < 0.001), and negatively correlated with SPA(r = - 0.504, R2 = 0.254, P < 0.001). However, no correlations were found between PI and SVA, SSA, TK, TLK or LL in AS patients. CONCLUSION: This study revealed that increasing PI was significantly correlated with more global sagittal imbalance, not with the local deformity in AS patients with thoracolumbar kyphosis.

Preoperative Pulse Pressure and Adverse Postoperative Outcomes: A Meta-Analysis.

OBJECTIVE: To evaluate the association between preoperative pulse pressure (PP) and the incidences of renal, neurologic, cardiac, and mortality outcomes after surgery. DESIGN: Systematic review and meta-analysis of cohort studies. SETTING: Hospitals. PARTICIPANTS: Patients who underwent cardiac or noncardiac surgeries. INTERVENTION: The preoperative PP was measured. MEASUREMENT AND MAIN RESULTS: Relevant cohort studies were obtained by systematic search of PubMed and Embase databases. A randomized effect model was used to pool the results. The multivariate adjusted risk ratio (RR) and its 95% confidence intervals (CI) were calculated to reflect the association between preoperative PP and adverse postoperative outcomes. Twelve cohort studies that included 40,143 patients who had undergone cardiac, vascular, or noncardiac surgery were included in the meta-analysis. The results showed that above a threshold of 40 mmHg, an increase in preoperative PP of 10 mmHg was independently associated with increased risk for renal events (adjusted RR: 1.13, 95% CI 1.08-1.19, p < 0.001; I2 = 0%), neurologic events (adjusted RR: 1.75, 95% CI 1.01-3.02, p = 0.04; I2 = 70%), cardiac events (adjusted RR: 1.19, 95% CI 1.03-1.37, p = 0.01; I2 = 0%), major cardiovascular adverse events (adjusted RR: 1.62, 95% CI 1.10-2.41, p = 0.02; I2 = 0%), and overall mortality (adjusted RR: 1.13, 95% CI 1.07-1.20, p < 0.001; I2 = 0%) after surgery. CONCLUSIONS: Patients with higher-than-normal preoperative PP are at increased risk for adverse postoperative outcomes.

Low pelvic incidence is associated with Andersson lesions in ankylosing spondylitis patients with kyphosis.

INTRODUCTION/OBJECTIVES: This study was to investigate the role of pelvic incidence (PI) in the development of Andersson lesions (ALs) in ankylosing spondylitis (AS) patients with kyphosis and to evaluate the difference in sagittal spinopelvic parameters between inflammatory ALs and mechanical ALs. METHOD: A total of 135 AS patients with kyphosis were reviewed. The patients were classified into AL group and non-AL group based on the presence or absence of ALs. Additionally, AS patients with ALs were also classified as either inflammatory or mechanical lesions depending on the radiological features of the lesions. The sagittal spinopelvic parameters of all these AS patients were measured and compared. Logistic regression analysis was performed to determine the powerful variables for predicting ALs in AS patients. RESULTS: ALs were detected in 34 patients (25.2%) of the total 135 AS patients. The mean PI of the AL group was 40.0°, which was significantly lower than that (48.3°) of the non-AL group (P < 0.001). No statistically significant difference was observed in PI (P = 0.350) between the inflammatory lesion group and the mechanical lesion group. Logistic regression analysis showed that only PI was a statistically significant risk factor for ALs (P < 0.001) and was negatively correlated with ALs (odds ratio = 0.76). CONCLUSIONS: These data suggest that low PI is closely associated with ALs in AS patients with kyphosis and that it might be a possible risk factor for the development of ALs. Moreover, both inflammatory and mechanical ALs patients had similarly low PI.Key Points• Low PI was closely associated with ALs in AS patients with kyphosis and might be a possible risk factor for development of ALs.• Either inflammatory or mechanical ALs patients had similar low PI.

Using a percutaneous spinal endoscopy unilateral posterior interlaminar approach to perform bilateral decompression for patients with lumbar lateral recess stenosis.

OBJECTIVE: To report the clinical and radiographic outcomes of 47 patients with bilateral symptomatic lumbar lateral recess stenosis (LLRS) treated with percutaneous spinal endoscopy (PSE) via a unilateral posterior interlaminar approach with bilateral decompression. METHODS: Forty-seven patients with single-level LLRS and bilateral symptoms who underwent PSE using a unilateral posterior interlaminar approach to perform bilateral decompression between May 2014 and June 2016 were reviewed retrospectively. Surgical-related data were collected, and clinical efficacy was evaluated using the Visual Analogue Scale (VAS) for back and leg pain, the Oswestry Disability Index (ODI), and the single continuous walking distance (SCWD) without pain at preoperative and postoperative time points. Patient satisfaction was evaluated by modified MacNab criteria at the one-year postoperative time point. RESULTS: All patients displayed improvements in clinical symptoms after surgery and were discharged the day of surgery. The mean operation time and blood loss were 91.17 ± 16.81 min and 13.53 ± 4.94 mL, respectively. At a mean follow-up of 18.33 ± 4.16 months, none of the patients required reoperation, while 6 of 47 patients experienced complications. VAS scores for back and leg pain, ODI, and SCWD were significantly improved at all postoperative time points compared with the preoperative values. Satisfactory (excellent or good) results were demonstrated in 44 of 47 patients (93.6%) at the one-year postoperative time point. CONCLUSIONS: The percutaneous spinal endoscopic technique via a unilateral posterior interlaminar approach for performing bilateral decompression is a less invasive, effective and safe surgery and can be considered an alternative option for treating patients with bilateral symptomatic LLRS.

BMP2 variants in the risk of ankylosing spondylitis.

The purpose of the study was to explore the genetic effects of bone morphogenetic protein (BMP2) polymorphisms on the susceptibility to ankylosing spondylitis (AS) in Chinese Han population. The case-control study included 120 AS cases and 110 healthy controls. Hardy-Weinberg equilibrium test was performed in control group. BMP2 rs235768 and rs3178250 polymorphisms were analyzed by polymerase chain reaction and direct sequencing. Additionally, the χ2  test was used to estimate association strength between BMP2 genetic polymorphisms and AS susceptibility, and the results were assessed via odds ratio (OR) with the corresponding 95% confidence interval (95%CI). Results adjustment was performed using logistic regression analysis. AA, AT, TT genotype and A, T allele frequencies of BMP2 rs235768 polymorphism presented no significant differences between case and control groups (P > .05 for all). TC genotype of rs3178250 polymorphism showed significantly higher in case group than that in control group (P = .048). After adjusting, TC genotype was a risk factor for AS (OR = 2.095; 95%CI = 1.086-4.038; P = .027). BMP2 rs3178250 polymorphism may increase individual susceptibility to AS in Chinese Han population.

Clinical results and surgery tactics of spinal osteotomy for ankylosing spondylitis kyphosis: experience of 428 patients.

OBJECTIVE: To report the clinical results and surgical tactics of spinal osteotomy for ankylosing spondylitis (AS) kyphosis based on the experiences of 428 patients. METHODS: From January 2003 to January 2015, a total of 428 patients suffering from AS kyphosis who underwent a one- or two-level pedicle subtraction osteotomy (PSO) or vertebral column decancellation (VCD) osteotomy in our hospital were reviewed. Pre- and postoperative radiological parameters and the chin-brow vertical angle (CBVA) were measured. Intraoperative, postoperative, and general complications were recorded. RESULTS: All patients could walk with horizontal vision and lie on their backs postoperatively. The pre- and postoperative average global kyphosis (GK) angles were corrected from 82.6 to 12.7° (p = 0.000) in the two-level group and from 55.8 to 9.6° (p = 0.000) in the one-level group, respectively. The mean sagittal vertical axis (SVA) improved from 29.4 to 8 cm (p = 0.000) in the two-level group and from 18.0 to 4.3 cm (p = 0.000) in the one-level group. The CBVA improved from 68.3 to 8.2° (p = 0.000) in the two-level group and from 46.2 to 4.2° (p = 0.000) in the one-level group. Although no major acute complications such as death or complete paralysis occurred, the complication rate was 6.5% in the one-level group and 23.6% in the two-level group. CONCLUSION: Spinal osteotomy, such as PSO and VCD, can improve the quality of life of AS patients as well as correct kyphotic deformities. The one-level spinal osteotomy showed a lower complication rate, while two-level spinal osteotomy was a relatively aggressive procedure that was more suitable in correcting severe AS kyphotic deformities.

Effect of osteoporosis on internal fixation after spinal osteotomy: A finite element analysis.

BACKGROUND: Severe kyphotic deformity can affect the quality of life of the elderly and is commonly treated by an osteotomy. Considering that the elderly often suffer from osteoporosis, the safety and efficacy of internal fixation are particularly important. The aim of this study was to analyse the effect of osteoporosis on internal fixation after spinal osteotomy. METHODS: One patient with a thoracolumbar kyphotic deformity who underwent spinal osteotomy was included. The CT images of the entire spine were used to construct a finite element model of the spine internal fixation after osteotomy. Material parameters were assigned to osteoporosis and normal bone groups, and the loads were used to simulate different working conditions, including axial compression, flexion, extension and lateral bending. FINDINGS: Compared with normal bone mass, the pressure on osteotomized vertebrae was reduced by 8.32%, 1.92%, 36.79% and 79.80% in mild osteoporosis model during axial compression, flexion, extension and lateral bending, respectively. The pressure on screws and rods was increased in an osteoporosis model under axial compression. During flexion and lateral bending, the pressure on screws was increased but was decreased on rods. The opposite result was found during extension. With the degree of osteoporosis increases, the change of stress is more obvious. INTERPRETATION: Under different bone mass conditions, the distribution patterns of stress in vertebrae, screws and rods were relatively similar. Collectively, the stress levels of vertebral bone were decreased and the stress levels of the screw/rod system were increased in an osteoporosis model compared to a normal bone model. Hence, osteoporosis may increase the risk of fracture and internal fixation failure.