Enlarged posterior column osteotomy plus intervertebral cage strutting for lumbosacral nerve bowstring disease.

BACKGROUND: To explore the surgical outcome of enlarged posterior column osteotomy (EPCO) plus intervertebral cage strutting (ICS) for patients with lumbosacral nerve bowstring disease (BSD). METHODS: The clinical data of 27 patients with BSD that surgically treated with EPCO plus ICS from January 2018 to March 2021 were retrospectively reviewed. Patient demographics including age, gender, body mass index (BMI), duration, length of hospital stay, SF-36 were recorded. Surgical data including operation time, blood loss, surgical level, and complications were recorded. Inter-pedicle distance and regional lumbar lordosis was measured at lateral X-ray at both pre- and postoperative. RESULTS: All patients underwent the operation successfully. EPCO plus ICS was performed at L4-L5 in 9 patients, at L5-S1 in 7 patients, at L4-S1 in 6 patients, at L3-L5 in 5 patients. The mean operation time was 96.3 ± 18.0 min, mean blood loss was 350.0 ± 97.9 mL. Relaxation of thecal sac was noticed after pedicle screw-rod compression bilaterally. The mean decrease of inter-pedicle distance was 0.57 ± 0.18 cm, the mean increase of regional lumbar lordosis was 17.6 ± 6.7 degrees. Relaxation of cauda equina within the thecal sac was noticed at intra-operative after pedicle screw-rod compression bilaterally in all the patients. Most patients achieved neurological function improvement at two-year follow up. CONCLUSIONS: EPCO plus ICS procedure is an effective surgical method for lumbosacral nerve BSD through restoring the coordination between column and cord, visual relaxation of cauda equina within the thecal sac at intraoperative is the key factor in determining the relief of neurological function at postoperative.

Does extreme weight loss after bariatric surgery alter spinopelvic parameters and ameliorate back pain? A retrospective case study.

OBJECTIVES: The aim of this study was to evaluate the effect of extreme weight loss on low back pain and spinopelvic parameters. PATIENTS AND METHODS: A total of 45 patients (11 males, 34 females; mean age: 40.2±9.4 years; range, 18 to 57 years) who had bariatric surgery between January 2018 and December 2021 were retrospectively analyzed. Radiological spinopelvic parameters including lumbar lordosis (LL), pelvic incidence (PI), spinopelvic harmony (when PI is within LL±10°), pelvic tilt (PT) and sacral slope (SS) were evaluated pre- and postoperatively. Clinical outcomes were assessed using the Visual Analog Scale-Back Pain (VAS-BP) and Oswestry Disability Index (ODI). RESULTS: The mean BMI loss at the end of the first year after surgery was 28.1±6.7% (range, 21 to 36%). The mean PI was 55.75°±12.47° preoperatively and 53.64°±11.86° at one year and the difference was -3.10°±5.25 (p=0.02), 1.10°±4.95° for PT (p=0.46), -2,70°±3.50° for SS (p<0.001), and 3.1±6.55 for LL (p<0.001). At one year, spinopelvic harmony remained unchanged in 31 patients, nine patients regained harmony, and was lost in five patients who had previously. No significant correlation between alterations in spinopelvic alignment and ODI scores was shown (p<0.05). The mean VAS-BP score was 40±30 mm preoperatively, and 20±3.5 mm postoperatively, indicating a difference of -39±29.5 (p<0.001). The mean ODI was 34.71±20.87 preoperatively, and 16±24 postoperatively, indicating a difference of -15±13 (p<0.001). Subgroup analyses showed that the change in SS was more pronounced with regard to PT change, particularly in young and female patients with >10 kg/m2 reduction in BMI (p<0.001). CONCLUSION: Weight loss after bariatric surgery improves lower back pain leading to changes in PT without affecting SS and altering PI.

Importance of the cervical paraspinal muscles in postoperative patient-reported outcomes and maintenance of sagittal alignment after anterior cervical discectomy and fusion.

OBJECTIVE: The aim of this study was to investigate the influence of preoperatively assessed paraspinal muscle parameters on postoperative patient-reported outcomes and maintenance of cervical sagittal alignment after anterior cervical discectomy and fusion (ACDF). METHODS: Patients with preoperative and postoperative standing cervical spine lateral radiographs and preoperative cervical MRI who underwent an ACDF between 2015 and 2018 were reviewed. Muscles from C3 to C7 were segmented into 4 functional groups: anterior, posteromedial, posterolateral, and sternocleidomastoid. The functional cross-sectional area and also the percent fat infiltration (FI) were calculated for all groups. Radiographic alignment parameters collected preoperatively and postoperatively included C2-7 lordosis and C2-7 sagittal vertical axis (SVA). Neck Disability Index (NDI) scores were recorded preoperatively and at 2 and 4-6 months postoperatively. To investigate the relationship between muscle parameters and postoperative changes in sagittal alignment, multivariable linear mixed models were used. Multivariable linear regression models were used to analyze the correlations between the changes in NDI scores and the muscles' FI. RESULTS: A total of 168 patients with NDI and 157 patients with sagittal alignment measurements with a median follow-up of 364 days were reviewed. The mixed models showed that a greater functional cross-sectional area of the posterolateral muscle group at each subaxial level and less FI at C4-6 were significantly associated with less progression of C2-7 SVA over time. Moreover, there was a significant correlation between greater FI of the posteromedial muscle group measured at the C7 level and less NDI improvement at 4-6 months after ACDF. CONCLUSIONS: The findings highlight the importance of preoperative assessment of the cervical paraspinal muscle morphology as a predictor for patient-reported outcomes and maintenance of C2-7 SVA after ACDF.

Reciprocal Changes in Sagittal Spinal Alignment After L5-S1 Anterior Lumbar Interbody Fusion.

OBJECTIVE: Degenerative diseases of the lumbar spine decrease lumbar lordosis (LL). Anterior lumbar interbody fusion (ALIF) at the L5-S1 disc space improves segmental lordosis, LL, and sagittal balance. This study investigated reciprocal changes in spinopelvic alignment after L5-S1 ALIF. METHODS: A retrospective chart review identified patients who underwent L5-S1 ALIF with or without posterior fixation at a single institution (November 1, 2016 to October 1, 2021). Changes in pelvic tilt, sacral slope, proximal LL (L1-L4), distal LL (L4-S1), total LL (L1-S1), segmental lordosis, pelvic incidence-LL mismatch, thoracic kyphosis, cervical lordosis, and sagittal vertical axis were measured on preoperative and postoperative radiographs. RESULTS: Forty-eight patients were identified. Immediate postoperative radiographs were obtained at a mean (SD) of 17 (20) days after surgery; delayed radiographs were obtained 184 (82) days after surgery. After surgery, patients had significantly decreased pelvic tilt (15.71° [7.25°] vs. 17.52° [7.67°], P = 0.003) and proximal LL (11.86° [10.67°] vs. 16.03° [10.45°], P < 0.001) and increased sacral slope (39.49° [9.27°] vs. 36.31° [10.39°], P < 0.001), LL (55.35° [13.15°] vs. 51.63° [13.38°], P = 0.001), and distal LL (43.17° [9.33°] vs. 35.80° [8.02°], P < 0.001). Segmental lordosis increased significantly at L5-S1 and decreased significantly at L2-3, L3-4, and L4-5. Lordosis distribution index increased from 72.55 (19.53) to 81.38 (22.83) (P < 0.001). CONCLUSIONS: L5-S1 ALIF was associated with increased L5-S1 segmental lordosis accompanied by pelvic anteversion and a reciprocal decrease in proximal LL. These changes may represent a reversal of compensatory mechanisms, suggesting an overall relaxation of spinopelvic alignment after L5-S1 ALIF.

Lumbar Lordosis is a Risk Factor for Lumbar Catheter Fracture of Lumboperitoneal Shunt.

OBJECTIVE: This study aimed to investigate the causes of lumboperitoneal (LP) shunt failure and determine risk factors for lumbar catheter fracture. METHODS: We retrospectively investigated 149 patients who underwent LP shunting in our hospital between January 2012 and March 2023. Shunt reconstruction occurred in 22 patients (14.8%). Among these, cause of failure was lumbar catheter fracture in 5 (22.7%). Patient backgrounds, cause of LP shunt failure, surgical technique factors, and anatomical characteristics were extracted for comparative analysis and risk factors of lumbar catheter fracture were analyzed. RESULTS: Compared with the no reoperation group (n = 127), patients in the lumbar catheter fracture tended to be younger (63 ± 20 vs. 72 ± 11 years) and favorable neurologic status (modified Rankin scale score ≤2) after initial LP shunt; however, the differences were not significant. Lumbar lordosis was significantly higher in the lumbar catheter fracture group (52.7°± 14.8° vs. 37.1°± 12.3°; P = 0.0067). CONCLUSIONS: Excessive lumbar lordosis is a risk factor for lumbar catheter fracture in patients undergoing LP shunting. Younger age and higher level of postoperative activities of daily living might also be associated with lumbar catheter fracture.

How does cervical sagittal profile change after the spontaneous compensation of global sagittal imbalance following one- or two-level lumbar fusion.

PURPOSE: This study aimed to evaluate the cervical sagittal profile after the spontaneous compensation of global sagittal imbalance and analyze the associations between the changes in cervical sagittal alignment and spinopelvic parameters. METHODS: In this retrospective radiographic study, we analyzed 90 patients with degenerative lumbar stenosis (DLS) and sagittal imbalance who underwent short lumbar fusion (imbalance group). We used 60 patients with DLS and sagittal balance as the control group (balance group). Patients in the imbalance group were also divided into two groups according to the preoperative PI: low PI group (≤ 50°), high PI group (PI > 50°). We measured the spinal sagittal alignment parameters on the long-cassette standing lateral radiographs of the whole spine. We compared the changes of spinal sagittal parameters between pre-operation and post-operation. We observed the relationships between the changes in cervical profile and spinopelvic parameters. RESULTS: Sagittal vertical axis (SVA) occurred spontaneous compensation (p = 0.000) and significant changes were observed in cervical lordosis (CL) (p = 0.000) and cervical sagittal vertical axis (cSVA) (p = 0.023) after surgery in the imbalance group. However, there were no significant differences in the radiographic parameters from pre-operation to post-operation in the balance group. The variations in CL were correlated with the variations in SVA (R = 0.307, p = 0.041). The variations in cSVA were correlated with the variations in SVA (R=-0.470, p = 0.001). CONCLUSION: Cervical sagittal profile would have compensatory changes after short lumbar fusion. The spontaneous decrease in CL would occur in patients with DLS after the spontaneous compensation of global sagittal imbalance following one- or two-level lumbar fusion. The changes of cervical sagittal profile were related to the extent of the spontaneous compensation of SVA.

Long-term efficacy of Waveflex semi-rigid-dynamic-internal-fixation system in delaying intervertebral disc degeneration at adjacent segments and improving spinal sagittal imbalance.

The Waveflex semi-rigid-dynamic-internal-fixation system shows good short-term effects in the treatment of lumbar degenerative diseases, but there are few long-term follow-up studies, especially for recovery of sagittal balance. Fifty patients with lumbar degenerative diseases treated from January 2016 to October 2017 were retrospectively analysed: 25 patients treated with Waveflex semi-rigid-dynamic-internal-fixation system (Waveflex group) and 25 patients treated with double-segment PLIF (PLIF group). Clinical efficacy was evaluated by Visual Analogue Scale (VAS) and Oswestry Disability Index (ODI). Imaging data before surgery and at 3 months, 1 year, and 5 years postoperatively was used for imaging indicator assessment. Local disc degeneration of the cephalic adjacent segment (including disc height index (DHI), intervertebral foramen height (IFH), and range of motion (ROM)) and overall spinal motor function (including lumbar lordosis (LL), pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), and |PI-LL|) were analysed. Regarding clinical efficacy, comparison of VAS and ODI scores between the Waveflex and PLIF groups showed no significant preoperative or postoperative differences. The comparison of the objective imaging indicators showed no significant differences in the DHI, IFH, LL, |PI-LL|, and SS values between the Waveflex and PLIF groups preoperatively and 3 months postoperatively (P > 0.05). These values were significantly different at 1 and 5 years postoperatively (P < 0.05), and the Waveflex group showed better ROM values than those of the PLIF group (P < 0.05). PI values were not significantly different between the groups, but PT showed a significant improvement in the Waveflex group 5 years postoperatively (P < 0.05). The Waveflex semi-rigid dynamic fixation system can effectively reduce the probability of intervertebral disc degeneration in upper adjacent segments. Simultaneously, patients in the Waveflex group showed postoperative improvements in LL, spinal sagittal imbalance, and quality of life.

Radiographic and surgery-related predictive factors for increased segmental lumbar lordosis following lumbar fusion surgery in patients with degenerative lumbar spondylolisthesis.

OBJECTIVE: This study aimed to evaluate preoperative (pre-op) radiographic characteristics and specific surgical interventions in patients with degenerative lumbar spondylolisthesis (DLS) who underwent lumbar fusion surgery (LFS), with a focus on analyzing predictors of postoperative restoration of segmental lumbar lordosis (SLL). METHODS: A retrospective review at a single center identified consecutive single-level DLS patients who underwent LFS between 2016 and 2022. Radiographic measures included disc angle (DA), SLL, lumbar lordosis (LL), anterior/posterior disc height (ADH/PDH), spondylolisthesis percentage (SP), intervertebral disc degeneration, and paraspinal muscle quality. Surgery-related measures included cage position, screw insertion depth, spondylolisthesis reduction rate, and disc height restoration rate. A change in SLL ≥ 4° indicated increased segmental lumbar lordosis (ISLL), and unincreased segmental lumbar lordosis (UISLL) < 4°. Propensity score matching was employed for a 1:1 match between ISLL and UISLL patients based on age, gender, body mass index, smoking status, and osteoporosis condition. RESULTS: A total of 192 patients with an average follow-up of 20.9 months were enrolled. Compared to UISLL patients, ISLL patients had significantly lower pre-op DA (6.78° vs. 11.84°), SLL (10.73° vs. 18.24°), LL (42.59° vs. 45.75°), and ADH (10.09 mm vs. 12.21 mm) (all, P < 0.05). ISLL patients were predisposed to more severe intervertebral disc degeneration (P = 0.047) and higher SP (21.30% vs. 19.39%, P = 0.019). The cage was positioned more anteriorly in ISLL patients (67.00% vs. 60.08%, P = 0.000), with more extensive reduction of spondylolisthesis (- 73.70% vs. - 56.16%, P = 0.000) and higher restoration of ADH (33.34% vs. 8.11%, P = 0.000). Multivariate regression showed that lower pre-op SLL (OR 0.750, P = 0.000), more anterior cage position (OR 1.269, P = 0.000), and a greater spondylolisthesis reduction rate (OR 0.965, P = 0.000) significantly impacted SLL restoration. CONCLUSIONS: Pre-op SLL, cage position, and spondylolisthesis reduction rate were identified as significant predictors of SLL restoration after LFS for DLS. Surgeons are advised to meticulously select patients based on pre-op SLL and strive to position the cage more anteriorly while minimizing spondylolisthesis to maximize SLL restoration.

Modified S1 Pedicle Subtraction Osteotomy.

STUDY DESIGN: Surgical technique video. OBJECTIVE: To report a surgical technique to revise patients with previous fusions at L4-S1 leading to an iatrogenic flat back and sagittal imbalance using L5-S1 transforaminal interbody fusion combined with a small S1 corner osteotomy. BACKGROUND: This is a case of a woman (51 y old) with a history of multiple lumbar surgeries, severe back pain, sagittal imbalance, and loss of lordosis. METHODS: We describe a feasible revision technique in a complex patient with the goal of attaining optimal distribution of lumbar lordosis and sagittal balance through a modified S1 pedicle subtraction osteotomy, and the use of an interbody cage to enhance the fusion rate and facilitate closure of the 3-column osteotomy. RESULTS: The preoperative patient lordosis angle of 31 degrees at L1-L4 and 16 degrees at L4-S1 became 12 degrees at L1-L4 and 44 degrees at L4-S1 postoperatively. CONCLUSION: The combination of L5-S1 transforaminal interbody fusion and S1 corner osteotomy is a feasible technique for the restoration of lumbar lordosis in patients with previous fusion and consequent loss of lordosis.

Surgical treatment of Roussouly type 1 with realigning Roussouly spinal shape and improving SRS-Schwab modifier: effect on minimal clinically important difference.

PURPOSE: To evaluate outcomes of choosing different Roussouly shapes and improving in Schwab modifiers for surgical Roussouly type 1 patients. METHODS: Baseline (BL) and 2-year (2Y) clinical data of adult spinal deformity (ASD) patients presenting with Roussouly type 1 sagittal spinal alignment were isolated in the single-center spine database. Patients were grouped into Roussouly type 1, 2 and 3 with anteverted pelvis (3a) postoperatively. Schwab modifiers at BL and 2Y were categorized as follows: no deformity (0), moderate deformity (+), and severe deformity (++) for pelvic tilt (PT), sagittal vertical axis (SVA), and pelvic incidence and lumbar lordosis mismatch (PI-LL). Improvement in SRS-Schwab was defined as a decrease in the severity of any modifier at 2Y. RESULTS: A total of 96 patients (69.9 years, 72.9% female, 25.2 kg/m2) were included. At 2Y, there were 34 type 1 backs, 60 type 2 backs and only 2 type 3a. Type 1 and type 2 did not differ in rates of reaching 2Y minimal clinically important difference (MCID) for health-related quality of life (HRQOL) scores (all P > 0.05). Two patients who presented with type 3a had poor HRQOL scores. Analysis of Schwab modifiers showed that 41.7% of patients improved in SVA, 45.8% in PI-LL, and 36.5% in PT. At 2Y, patients who improved in SRS-Schwab PT and SVA had lower Oswestry disability index (ODI) scores and significantly more of them reached MCID for ODI (all P < 0.001). Patients who improved in SRS-Schwab SVA and PI-LL had more changes of VAS Back and Short Form-36 (SF-36) outcomes questionnaire physical component summary (SF-36 PCS), and significantly more reached MCID (all P < 0.001). By 2Y, type 2 patients who improved in SRS-Schwab grades reached MCID for VAS back and ODI at the highest rate (P = 0.003, P = 0.001, respectively), and type 1 patients who improved in SRS-Schwab grades reached MCID for SF-36 PCS at the highest rate (P < 0.001). CONCLUSION: For ASD patients classified as Roussouly type 1, postoperative improvement in SRS-Schwab grades reflected superior patient-reported outcomes while type 1 and type 2 did not differ in clinical outcomes at 2Y. However, development of type 3a should be avoided at the risk of poor functional outcomes. Utilizing both classification systems in surgical decision-making can optimize postoperative outcomes.

Artificial Intelligence Assistance for the Measurement of Full Alignment Parameters in Whole-Spine Lateral Radiographs.

BACKGROUND: Measuring spinal alignment with radiological parameters is essential in patients with spinal conditions likely to be treated surgically. These evaluations are not usually included in the radiological report. As a result, spinal surgeons commonly perform the measurement, which is time-consuming and subject to errors. We aim to develop a fully automated artificial intelligence (AI) tool to assist in measuring alignment parameters in whole-spine lateral radiograph (WSL X-rays). METHODS: We developed a tool called Vertebrai that automatically calculates the global spinal parameters (GSPs): Pelvic incidence, sacral slope, pelvic tilt, L1-L4 angle, L4-S1 lumbo-pelvic angle, T1 pelvic angle, sagittal vertical axis, cervical lordosis, C1-C2 lordosis, lumbar lordosis, mid-thoracic kyphosis, proximal thoracic kyphosis, global thoracic kyphosis, T1 slope, C2-C7 plummet, spino-sacral angle, C7 tilt, global tilt, spinopelvic tilt, and hip odontoid axis. We assessed human-AI interaction instead of AI performance alone. We compared the time to measure GSP and inter-rater agreement with and without AI assistance. Two institutional datasets were created with 2267 multilabel images for classification and 784 WSL X-rays with reference standard landmark labeled by spinal surgeons. RESULTS: Vertebrai significantly reduced the measurement time comparing spine surgeons with AI assistance and the AI algorithm alone, without human intervention (3 minutes vs. 0.26 minutes; P < 0.05). Vertebrai achieved an average accuracy of 83% in detecting abnormal alignment values, with the sacral slope parameter exhibiting the lowest accuracy at 61.5% and spinopelvic tilt demonstrating the highest accuracy at 100%. Intraclass correlation analysis revealed a high level of correlation and consistency in the global alignment parameters. CONCLUSIONS: Vertebrai's measurements can accurately detect alignment parameters, making it a promising tool for measuring GSP automatically.

Single Position Lateral versus Prone Transpsoas Lateral Interbody Fusion Inclusive of L4-L5: A Single Surgeon Experience Examining Early Postoperative Outcomes.

OBJECTIVE: The transpsoas lateral lumbar interbody fusion (LLIF) procedure is a minimally invasive lumbar spine approach that provides indirect neural decompression, improved sagittal alignment, and a high fusion rate. Typically accompanied by posterior pedicle screw insertion, there has been interest in performing LLIF in a single position to decrease cost and time under anesthesia. However, there is a paucity of direct comparisons between single-position LLIF via prone versus lateral decubitus positioning. Therefore, this study aims to compare the outcomes of a single surgeon performing prone versus lateral single-position LLIF, inclusive of the L4-L5 level. METHODS: A retrospective review was performed of a consecutive case series of patients who underwent either prone or lateral, single-position LLIF by a single surgeon. All cases involved the L4-L5 level. Demographic data, perioperative details, clinical outcomes, and preoperative and postoperative lumbar lordosis were recorded. RESULTS: Sixty-three patients underwent lateral and 16 patients underwent prone single-position LLIF. Demographics and average interbody size were similar between groups. Operative time, change in lumbar lordosis, and length of hospital stay did not differ between the 2 positions. Both groups performed similarly in terms of preoperative and postoperative visual analog score pain score and complications. Patients who underwent lateral position LLIF ambulated farther on postoperative day 1 (250 feet vs. 200 feet, P = 0.015). Average time to follow up was 53 weeks. CONCLUSIONS: This study demonstrates promising preliminary results indicating that single-position LLIF performs well, even at the L4-L5 level, in both the prone and lateral positions.

Comparison of Three Grafting Options for Anterior Cervical Corpectomy and Fusion: A Retrospective 3-Arms Case Control Study.

BACKGROUND: Anterior cervical corpectomy and fusion achieves foraminal radicular and central medullary decompression and spinal stabilization in staged lesions. Many bone graft materials have been developed for the reconstruction of cervical lordosis and the restoration of intervertebral height after corpectomy. The PolyEtherKetoneEtherKetoneKetone (PEKEKK) is a semicrystalline thermoplastic polymer that can be reinforced with carbon fibers to create long and highly fenestrated rectangular cervical cages for corpectomy. This study aimed to evaluate the radiological outcomes of an innovative PEKEEKK cage compared with others grafting options. METHODS: Forty-five consecutive patients who underwent surgery with PEKEKK cages between 2017 and 2019 at a spine institution, were matched with 15 patients with a titanium mesh cylindrical cage (TMC) and 15 patients with a tricortical structural iliac bone graft. The restoration of vertebral height and cervical lordosis postoperatively, and subsidence of the construct were evaluated. Complications were reported. RESULTS: The minimal follow-up was 5.1±2years. A better, but nonsignificant, postoperative gain in height was observed for PEKEKK (+8.1 ± 20%) and TMC cages (+8.2 ± 16%) than for iliac crest autograft reconstruction (+2.3 ± 15%, P = 0.119). The mean subsidence at the last follow-up was greater for TMC cages (-10.2 ± 13%), but was not significant, with -6.1 ± 10% for PEKEKK cages and -4.1 ± 7% for iliac crest autografts (P = 0.223). The gain in segmental cervical lordosis was significant (P < 0.001) and remained stable in all the groups. CONCLUSIONS: Although an improvement in radiologic anatomical parameters can be achieved with all cage groups, the PEKEKK cage can be considered as a safe alternative for reducing subsidence.

Can postoperative Cobb and pelvic obliquity corrections be predicted using supine traction X-rays in non-ambulatory patients with cerebral palsy fused to L5? A case series study.

PURPOSE: This study aimed to determine whether Cobb and pelvic obliquity corrections can be predicted using supine traction radiographs in patients with cerebral palsy (CP) who underwent posterior spinal fusion (PSF) from T2/3 to L5. METHODS: From January 2010 to January 2020, 167 non-ambulatory patients with CP scoliosis underwent PSF using pedicle screws in two quaternary centers with a minimum of 2 years follow-up (FU). Radiological measurements and chart reviews were performed. RESULTS: A total of 106 patients aged 15.6 ± 0.4 years were included. All patients had significant correction of the Cobb angle (MC), pelvic obliquity (PO), thoracic kyphosis (TK), and lumbar lordosis (LL) without loss of correction at the last FU (LFU). Curve flexibility was significantly correlated with Cobb correction (δMC) immediately postoperatively (p < 0.0001, r = 0.8950), followed by the amount of correction in pelvic obliquity under traction (δPOT) (p = 0.0252, r = 0.2174). For correction in PO (δPO), the most significant variable was δPOT (p < 0.0001, r = 0.7553), followed by curve flexibility (p = 0.0059, r = 0.26) and the amount of correction in Cobb under traction (p = 0.0252, r = 0.2174). CONCLUSIONS: Cobb and PO corrections can be predicted using supine traction films for non-ambulatory CP patients treated with PSF from T2/3 to L5. The variables evaluated were interconnected, reinforcing preoperative planning for these patients. Comparative large-scale studies on patient-related clinical outcomes are required to determine whether this predicted correction is associated with improved surgical outcomes and reduced complication rates. LEVEL OF EVIDENCE: IV.

Spinopelvic morphology impacts on postoperative proximal junctional kyphosis in congenital scoliosis with thoracolumbar hemivertebrae.

PURPOSE: It aims to investigate the lumbar and pelvic morphology in congenital scoliosis with thoracolumbar hemivertebrae and its impact on proximal junctional kyphosis (PJK) incidence after hemivertebra resection and short fusion. METHODS: 23 congenital scoliosis patients with thoracolumbar hemivertebra aged between 10 and 18 years were enrolled in the retrospective study. Spinopelvic sagittal parameters were analyzed on whole-spine standing lateral radiographs preoperatively, one-week postoperatively and at the final follow-up. Pearson correlations were calculated for local kyphosis (LK), lumbar and pelvic morphology parameters. Binary logistic regression and receiver operating characteristics (ROC) curve analysis were performed to identify the risk factors for PJK. RESULTS: Thoracolumbar hemivertebra caused LK of 29.2° ± 17.3°, an increased lumbar lordosis (LL) (-64.7° ± 16.3°), lower LL apex (52.2% at L5), and small pelvic incidence (PI) (36.8° ± 6.6°). LK was correlated with lumbar morphology parameters, including LL (r = - 0.837), upper arc of LL (LLUA) (r = - 0.879), thoracolumbar kyphosis (TLK) (r = 0.933), thoracic kyphosis (TK) (r = 0.762) and TK apex (TKA) (r = - 0.749). Surgical treatment improved the lumbar morphology, but not pelvic morphology. At the final follow-up, LL had returned to its preoperative value (p = 0.158). PJK occurred in 30.4% of cases as a compensatory mechanism. Preoperatively, significant differences of parameters between non-PJK and PJK groups were observed in LK and TLK. Binary logistic regression identified three independent risk factors for PJK: preoperative LLA (OR = 0.005, 95%CI = 0.000-0.287, p = 0.011), preoperative TLK (OR = 1.134, 95%CI = 1.001-1.286, p = 0.048), and preoperative lumbar lordosis morphology type (OR = 5.507, 95%CI = 1.202-25.227, p = 0.028). However, residual LK after surgery was not correlated with PJK incidence. ROC curve analysis verified that preoperative TLK > 22.59° was associated with increased PJK incidence after surgery. CONCLUSIONS: Lumbar morphology changes as a compensatory mechanism beneath the thoracolumbar hemivertebra. However, a stable pelvis tends to allow the LL to return to its preoperative value. PJK occurred as a cranial compensatory mechanism for increasing LL and corrected TLK. A larger TLK (> 22.59°) was an independent risk factor for PJK incidence in patients with type 2 and 3A lumbar lordosis morphology.

What factors are associated with a better restoration of pelvic version after adult spinal deformity surgery?

INTRODUCTION: Poor restoration of pelvic version after adult spinal deformity (ASD) surgery is associated with an increased risk of mechanical complications and worse quality of life. We studied the factors linked to the improvement of postoperative pelvic version. MATERIALS AND METHODS: This is a retrospective analysis of a prospective multicenter ASD database. Selection criteria were: operated patients having preoperative severe pelvic retroversion as per GAP score (Relative Pelvic Version-RPV < - 15°); panlumbar fusions to the pelvis; 2-year follow-up. Group A comprised patients with any postoperative improvement of RPV score, and group B had no improvement. Groups were compared regarding baseline characteristics, surgical factors, and postoperative sagittal parameters. Parametric and non-parametric analyses were employed. RESULTS: 177 patients were studied, median age 67 years (61; 72.5), 83.6% female. Groups were homogeneous in baseline demographics, comorbidities, and preoperative sagittal parameters (p > 0.05). The difference in RPV improvement was 11.56º. Group A (137 patients) underwent a higher percentage of ALIF procedures (OR = 6.66; p = 0.049), and posterior osteotomies (OR = 4.96; p < 0.001) especially tricolumnar (OR = 2.31; p = 0.041). It also showed a lower percentage of TLIF procedures (OR = 0.45; p = 0.028), and posterior decompression (OR = 0.44; p = 0.024). Group A displayed better postoperative L4-S1 angle and relative lumbar lordosis (RLL), leading to improved sacral slope (and RPV), and global alignment (RSA). Group A patients had longer instrumentations (11.45 vs 10; p = 0.047) and hospitalization time (13 vs 11; p = 0.045). All postoperative sagittal parameters remained significantly better in group A through follow-up. However, differences between the groups narrowed over time. CONCLUSIONS: ALIF procedures and posterior column osteotomies improved pelvic version postoperatively, and associated better L4-S1 and lumbar lordosis restoration, indirectly improving all other sagittal parameters. However, these improvements seemed to fade during the 2-year follow-up.

Cervical Sagittal Alignment and Related Factor Analysis and Prediction Model in Patients Undergoing Revision Surgery After Anterior Cervical Fusion.

INTRODUCTION: Patients with myelopathy or radiculopathy commonly undergo anterior cervical fusion surgery (ACFS), which has a notable failure rate on occasion. The goal of this study was to compare revision and nonrevision surgery patients in cervical sagittal alignment (CSA) subsequent to ACFS; additionally, to identify the best CSA parameters for predicting clinical outcome after ACFS; and furthermore, to create an equation model to assist surgeons in making decisions on patients undergoing ACFS. METHODS: The data of 99 patients with symptomatic cervical myelopathy/radiculopathy who underwent ACFS were analyzed. Patients were divided into group A (underwent revision surgery after the first surgery failed) and group B (underwent only the first surgery). We measured and analyzed both preoperative and postoperative CSA parameters, including C2 slope, T1 slope, cervical lordosis C2-C7 (CL), C2-C7 sagittal vertical axis (C2C7 SVA), occiput-C2 lordosis angle (C0-C2), and chin brow vertical angle, and we further computed the correlation between the CSA parameters and created a prediction model. RESULTS: The (T1S-CL)-C2S mismatch differed significantly between groups A and B ([9.95 ± 9.95] 0 , [3.79 ± 6.58] 0 , P < 0.05, respectively). A significant correlation was observed between C2 slope and T1CL in group B relative to group A postoperatively (R 2 = 0.42 versus R 2 = 0.09, respectively). Compared with group B, patients in group A had significantly higher C2C7SVA values, more levels of fusion, and more smokers. The sensitivity, specificity, accuracy, and discrimination of the model were, respectively, 73.5%, 84%, 78.8%, and 85.65%. CONCLUSION: The causes of revision surgery in cervical myelopathic patients after anterior cervical corpectomy and fusion/anterior cervical diskectomy and fusion are multifactorial. (T1S-CL)-C2S mismatch and high C2C7SVA are the best cervical sagittal parameters that increase the odds of revision surgery, and the effect is more enhanced when comorbidities such as smoking, low bone-mineral density, and increased levels of fusion are taken into account.

Lumbar lordosis and sacral slope do not differ in two types of postoperative lumbar disc re-herniation: a cross-sectional observational study.

BACKGROUND: To identify the differences of lumbar lordosis (LL) and sacral slope (SS) angles between two types of postoperative lumbar disc re-herniation, including the recurrence of same level and adjacent segment herniation (ASH). METHODS: We searched the medical records of lumbar disc herniation (LDH) patients with re-herniation with complete imaging data (n = 58) from January 1, 2013 to December 30, 2020 in our hospital. After matching for age and sex, 58 patients with LDH without re-herniation from the same period operated by the same treatment group in our hospital were served as a control group. Re-herniation patients were divided into two groups, same-level recurrent lumbar disc herniation group (rLDHG) and adjacent segment herniation group with or without recurrence (ASHG). The preoperative, postoperative and one month after operation LL and SS were measured on standing radiographs and compared with the control group by using t-test, ANOVA, and rank-sum test. Next, we calculated the odds ratios (ORs) by unconditional logistic regression, progressively adjusted for other confounding factors. RESULTS: Compared with the control group, the postoperative LL and SS were significantly lower in LDH patients with re-herniation. However, there were no differences in LL and SS between ASHG and rLDHG at any stage. After progressive adjustment for confounding factors, no matter what stage is, LL and SS remained unassociated with the two types of re-herniation. CONCLUSIONS: Low postoperative LL and SS angles are associated with degeneration of the remaining disc. Low LL and SS may be independent risk factors for re-herniation but cannot determine type of recurrence (same or adjacent disc level).

Could the different surgical goals of fusion and non-fusion also be achieved in combination within the same patient? Clinical and radiological outcome of hybrid cervical spine surgery.

PURPOSE: Hybrid cervical spine surgery (HS) is a novel surgical strategy wherein an artificial disc replacement is done with a cervical fusion nearby with a stand-alone titanium cage to combine the advantages in both procedures. The aim of this study was to evaluate interactions of these devices within the same patient, and to analyze, if the different goal of each implant is accomplished. METHODS: Thirty-six patients were treated surgically within a non-randomized retrospective study framework with HS. Patients were examined preoperatively followed by clinical and radiological examination at least one year postoperative. Clinical outcome was detected with NDI, VAS arm/neck, pain self-assessment questionnaires and subjective patient satisfaction. Radiological assessments included RoM, segmental lordosis, cervical lordosis of C2-C7, subsidence, ap-migration and heterotopic ossifications (HO) at the cTDR levels. RESULTS: Statistically significant improvement of all clinical scores was observed (NDI 37.5 to 5.76; VASarm 6.41 to 0.69; VASneck 6.78 to 1.48). Adequate RoM was achieved at cTDR levels. RoM in the ACDF levels was reduced statistically significant (p < 0.001), and solid fusion (> 2°) was achieved in all evaluated fusion level. Global lordosis (C2-C7) increased statistically significant (2.4° to 8.1°). Subsidence and HO at the cTDR levels did not occur. CONCLUSIONS: HS results in preservation of the segmental motion in the cTDR and fast and solid fusion in the cage cohort simultaneously. Patient safety was proven. In carefully selected cases, HS is a safe and viable treatment option by choosing the right "philosophy" level per level.

Influence of pelvic tilt correction on PJK occurrence after adult spinal deformity surgery.

INTRODUCTION: Many risk factors for proximal junctional kyphosis (PJK) have been reported in the literature, especially sagittal alignment modifications, but studies on pelvic tilt (PT) variations and its influence on PJK are missing. Aim of this study was to analyze the influence of pelvic tilt correction, after long fusion surgery for ASD patients, on PJK occurrence. METHODS: A monocentric retrospective study was conducted on prospectively collected data, including 76 patients, operated with fusion extending from the thoraco-lumbar junction to the ilium. Radiologic parameters were measured on fullspine standing radiographs preoperatively, postoperatively (<6 months) and at latest follow-up (before revision surgery or >2 years). All parameters were analyzed comparing patients with PJK (group "PJK") and without PJK (group "no PJK"). A further analysis compared patients with low (PT/PI<25th percentile, LowPT group) and high (PT/PI>75th percentile, HighPT group) preoperative pelvic tilt. RESULTS: « PJK ¼ patients had a greater lumbar lordosis and thoracic kyphosis correction (p=0,03 et <0,001 respectively) compared to the "no PJK" patients. Pelvic tilt was significantly lower postoperatively in the "PJK" group (p=0,03). Patients from the HighPT PJK group were significantly more corrected than patients from the HighPT noPJK group (p=0,003). CONCLUSION: Through the analysis of 76 patients, we showed that pelvic tilt did not seem to play a role in the setting of PJK after ASD surgery. Decreasing PT after surgery could be an element to watch out for in patients with PJK risk factors.