Search

The MIS PSO is a hybrid approach using less-invasive surgical approaches combined with traditional open spinal deformity techniques for the treatment of adult spinal deformities. The MIS PSO allows for the correction of spinal deformities in the coronal and sagittal planes, even in the fixed spine, and simultaneously mitigating the morbidity of traditional open surgery by preserving the soft tissues and minimizing blood loss. This article discusses the surgical steps of the MIS PSO and reviews our experience., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: Pedicle subtraction osteotomy (PSO) can improve sagittal alignment but carries risks, including iatrogenic spinal cord and nerve root injury. Critically, during the reduction phase of the technique, medullary kinking or neural element compression can lead to neurologic deficits., Methods: We describe 3 cases of thoracic PSO and evaluate the feasibility, findings, and utility of intraoperative ultrasound in this setting., Results: Intraoperative ultrasound can provide a visual assessment of spinal cord morphology before and after PSO reduction and influences surgical decision making with regard to the final amount of sagittal plane correction. This modality is particularly useful for confirming ventral decompression of disc-osteophyte complex before reduction and also after reduction maneuvers when there is kinking of the thecal sac but uncertainty about the underlying status of the spinal cord. Intraoperative ultrasound is a reliable modality that fits well into the technical sequence of PSO, adds a minimal amount of operative time, and has few limitations., Conclusions: We propose that intraoperative ultrasound is a useful supplement to standard neuromonitoring modalities for ensuring safe PSO reduction and decompression of neural elements., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Purpose: To propose a complementary classification to the Schwab's osteotomy classification that would regroup together under a common umbrella different published pedicle subtraction osteotomy (PSO) variations that are commonly used, to have a common language and complete the spine surgeon's armamentarium when dealing with rigid spinal deformities., Methods: The 2 general types corresponding to the grades 3 and 4 of the Schwab classification were separated into 6 gradual subtypes (grades 3A, 3B, 3C, 4A, 4B, 4C). The classification is based on the amount of resected pedicle, the inclusion or not of the disc above, and the location of the axis of rotation. Based on the proposed classification, a reliability study was performed using 18 cases that were classified by 8 readers with expertise in the management of adult deformities with the use of osteotomies., Results: Clinical cases were classified according to the 6 grades proposed in the classification. The intra-rater reliability for the classification was "almost perfect agreement" with a Fleiss kappa coefficient average of 0.92 (range 0.85-1.00). The inter-rater reliability was "almost perfect agreement" with a coefficient average of 0.90 for the 2 readings that were done at an interval of 2 weeks., Conclusion: The developed classification proved to be reliable and intuitive. It is an original way to display a catalog of different available PSO modifications including the original technique, in a logical and gradual order to help the surgeons in their decisions and show them that between a grade 2 osteotomy and a grade 5 osteotomy, many intermediate options are available. Further work with a treatment algorithm for clinical practice based on the current classification may be developed in the future.

Purpose: To investigate the biomechanical effects of anterior column realignment (ACR) and pedicle subtraction osteotomy (PSO) on local lordosis correction, primary stability and rod strains., Methods: Seven cadaveric spine segments (T12-S1) underwent ACR at L1-L2. A stand-alone hyperlordotic cage was initially tested and then supplemented with posterior bilateral fixation. The same specimens already underwent a PSO at L4 stabilized by two rods, a supplemental central rod (three rods) and accessory rods (four rods) with and without adjacent interbody cages (La Barbera in Eur Spine J 27(9):2357-2366, 2018). In vitro flexibility tests were performed under pure moments in flexion/extension (FE), lateral bending (LB) and axial rotation (AR) to determine the range of motion (RoM), while measuring the rod strains with strain gauge rosettes., Results: Local lordosis correction with ACR (24.7° ± 3.7°) and PSO (25.1° ± 3.9°) was similar. Bilateral fixation significantly reduced the RoM (FE: 31%, LB: 2%, AR: 18%), providing a stability consistent with PSO constructs (p > 0.05); however, it demonstrates significantly higher rod strains compared to PSO constructs with lateral accessory rods and interbody cages in FE and AR (p < 0.05), while being comparable in FE or slightly higher in AR compared to PSO constructs with two and three rods., Conclusion: Bilateral posterior fixation is highly recommended following ACR to provide adequate primary stability. However, primary rod strains in ACR were found comparable or higher than weak PSO construct associated with frequent rod failure; therefore, caution is recommended. These slides can be retrieved under Electronic Supplementary Material.

Purpose: The biomechanical performance of conventional multi-rod configurations (satellite rods and accessory rods) in pedicle subtraction osteotomies has been previously studied in vitro and using finite element models (FEM). Delta and delta-cross rods are innovative multi-rod configurations where the rod bends were placed only in its proximal and distal extremities in order to obtain a dorsal translation of the central part of the rod respect to the most angulated area of the main rods. However, the biomechanical properties of the delta and delta-cross rods have not been investigated. This study used FEM to analyze the effect of delta-rod configurations on the stiffness and primary rod stress reduction in multiple-rod constructs after pedicle subtraction osteotomy., Methods: The global range of motion in the spine and the magnitude and distribution of the von Mises stress in the rods were studied using a spine finite element model described previously. A follower load of 400 N along with moments of 7.5 N in flexion/extension, lateral bending, and axial rotation were tested on the spine model. Initial breakage was created on the rod based on the maximum stress location. The post-breakage models were tested under flexion., Results: Delta and delta-cross rods reduced more range of motion (up to 45% more reduction) and reduced more primary rod stress than other previously tested rod configurations (up to 48% more reduction). After initial rod fracture occurred, delta and delta-cross rods also had less range of motion (up to 23.6% less) and less rod von Mises stress (up to 81.2% less) than other rod configurations did., Conclusions: Delta and delta-cross rods have better biomechanical performance than satellite rods and accessory rods in pedicle subtraction osteotomies in terms of construct stiffness and rod stress reduction. After the initial rod breakage occurred, the delta and delta-cross rods could minimize the loss of fixation, which have less rod stress and greater residual stiffness than other rod configurations do. Based on this FEA study, delta-rod configurations show more favorable biomechanical behavior than previously described multi-rod configurations. These slides can be retrieved under Electronic Supplementary Material.

OBJECTIVESignificant blood loss and coagulopathy are often encountered during adult spinal deformity (ASD) surgery, and the optimal intraoperative transfusion algorithm is debatable. Rotational thromboelastometry (ROTEM), a functional viscoelastometric method for real-time hemostasis testing, may allow early identification of coagulopathy and improve transfusion practices. The objective of this study was to investigate the effect of ROTEM-guided blood product management on perioperative blood loss and transfusion requirements in ASD patients undergoing correction with pedicle subtraction osteotomy (PSO).METHODSThe authors retrospectively reviewed patients with ASD who underwent single-level lumbar PSO at the University of Virginia Health System. All patients who received ROTEM-guided blood product transfusion between 2015 and 2017 were matched in a 1:1 ratio to a historical cohort treated using conventional laboratory testing (control group). Co-primary outcomes were intraoperative estimated blood loss (EBL) and total blood product transfusion volume. Secondary outcomes were perioperative transfusion requirements and postoperative subfascial drain output.RESULTSThe matched groups (ROTEM and control) comprised 17 patients each. Comparison of matched group baseline characteristics demonstrated differences in female sex and total intraoperative dose of intravenous tranexamic acid (TXA). Although EBL was comparable between ROTEM versus control (3200.00 ± 2106.24 ml vs 3874.12 ± 2224.22 ml, p = 0.36), there was a small to medium effect size (Cohen's d = 0.31) on EBL reduction with ROTEM. The ROTEM group had less total blood product transfusion volume (1624.18 ± 1774.79 ml vs 2810.88 ± 1847.46 ml, p = 0.02), and the effect size was medium to large (Cohen's d = 0.66). This difference was no longer significant after adjusting for TXA (β = -0.18, 95% confidence interval [CI] -1995.78 to 671.64, p = 0.32). More cryoprecipitate and less fresh frozen plasma (FFP) were transfused in the ROTEM group patients (cryoprecipitate units: 1.24 ± 1.20 vs 0.53 ± 1.01, p = 0.03; FFP volume: 119.76 ± 230.82 ml vs 673.06 ± 627.08 ml, p < 0.01), and this remained significant after adjusting for TXA (cryoprecipitate units: β = 0.39, 95% CI 0.05 to 1.73, p = 0.04; FFP volume: β = -0.41, 95% CI -772.55 to -76.30, p = 0.02). Drain output was lower in the ROTEM group and remained significant after adjusting for TXA.CONCLUSIONSFor ASD patients treated using lumbar PSO, more cryoprecipitate and less FFP were transfused in the ROTEM group compared to the control group. These preliminary findings suggest ROTEM-guided therapy may allow early identification of hypofibrinogenemia, and aggressive management of this may reduce blood loss and total blood product transfusion volume. Additional prospective studies of larger cohorts are warranted to identify the appropriate subset of ASD patients who may benefit from intraoperative ROTEM analysis.

Purpose: This retrospective study investigates sagittal alignment after pedicle subtraction osteotomy (PSO). The purpose was to investigate factors associated with malalignment recurrence., Methods: Full spine radiographs were analyzed in 66 patients (average age 54.5 years, follow-up 3.8 years). Measurements were taken preoperatively, 3 months postoperatively, at follow-up: SVA C2 and C7, C2-C7 lordosis, T4-T12 kyphosis, L1-S1 lordosis, PSO lordosis, pelvic incidence, pelvic tilt, sacral slope. Follow-up CTs were screened for pseudarthrosis and gas in sacroiliac joints., Results: PSO lordosis increased from 11.8° to 40.8° (p < 0.0001) and kept stable. Lumbar lordosis increased from 28.6° to 57.7° (p < 0.0001) and decreased to 49.7° (p = 0.0008). Pelvic tilt decreased from 29.2° to 16.5° (p < 0.0001) and increased to 22.5° (p < 0.0001). SVA C7 decreased from 105.1 to 35.5 mm (p < 0.0001) and increased to 64.8 mm (p = 0.0005). Twenty-eight patients (42%) had an SVA C7 increase of more than 70 mm in the postoperative course: recurrence group. These patients were older: 62.8 years versus 52.3 years (p = 0.0031). Loss of lordosis was 11.9° (recurrence group) versus 5.0° (non-recurrence group). Eleven patients (17%) had pseudarthrosis. Pelvic incidence increased by 9.3° (recurrence group) versus 3.8° (non-recurrence group). In 23 patients (35%), pelvic incidence increased > 10°. Gas was evidenced in sacroiliac joints in 22 patients (33%)., Conclusion: Postoperative anterior malalignment recurrence may occur after PSO. Elderly patients were at risk of recurrence. Loss of lumbar lordosis linked to pseudarthrosis represented another factor. With malalignment recurrence, anterior trunk rotation and pelvic retroversion might additionally have augmented moments across sacroiliac joints with subsequent ligament laxity and pelvic incidence increase. These slides can be retrieved under Electronic Supplementary Material.

Purpose: To investigate the effect of anterior interbody cages, accessory and satellite rods usage on primary stability and rod strains for PSO stabilization., Methods: Seven human cadaveric spine segments (T12-S1) underwent PSO at L4 with posterior fixation from L2 to S1. In vitro flexibility tests were performed under pure moments in flexion/extension (FE), lateral bending (LB) and axial rotation (AR) to determine the range of motion, while measuring the strains on the primary rods with strain gauge rosettes. Six constructs with 2, 3 and 4 rods, with and without interbody cages implantation adjacent to the PSO site, were compared., Results: All constructs had comparable effects in reducing spine kinematics compared to the intact condition (- 94% in FE and LB; - 80% in AR). Supplementation of 2 rods with lateral accessory rods (4 rods) was the most effective strategy in minimizing primary rod strains, particularly when coupled to cages (p ≤ 0.005; - 50% in FE, - 42% in AR and - 11% in LB); even without cages, the strains were significantly reduced (p ≤ 0.009; - 26%, - 37%, - 9%). The addition of a central satellite rod with laminar hooks (3 rods) effectively reduced rod strains in FE (p ≤ 0.005; - 30%) only in combination with cages., Conclusions: The study supports the current clinical practice providing a strong biomechanical rationale to recommend 4-rod constructs based on accessory rods combined with cages adjacent to PSO site. Although weaker, the usage of accessory rods without cages and of a central satellite rod with hooks in combination with interbody spacers may also be justified. These slides can be retrieved under Electronic Supplementary Material.

Study Design: Retrospective review of high-dose tranexamic acid (TXA) use in consecutive patients., Objective: To determine the safety profile of a high-dose TXA protocol in complex adult spinal deformity patients., Summary of Background Data: Adult spinal deformity (ASD) surgery may involve significant amounts of blood loss, especially when various osteotomy techniques are used. Antifibrinolytic agents such as TXA have been used to reduce intraoperative blood loss. However, there is no universally accepted dosing protocol for its use during complex ASD surgery., Methods: Consecutive patients undergoing spinal deformity correction over a 14-month period at a single institution were identified. Inclusion criteria were adults (age ≥18 years) who underwent posterior spinal fusion of at least 5 levels and use of our standard TXA protocol of 50 mg/kg intravenous loading dose followed by a 5-mg/kg/h infusion until skin closure. Patient demographics, estimated blood loss (EBL), operative time, transfusion rates, complications, and other procedure-specific information were recorded., Results: A total of 100 adult patients were included. All operative procedures were performed by the senior surgeon. The mean age was 47.3 years, and 71% of patients were female. Average body mass index was 24.9. The average fusion length was 14 levels; 33/100 patients had fusion constructs of 17 levels or more. Pedicle subtraction osteotomy was performed in 9 patients and vertebral column resections were performed in 14 patients. There were 45/100 patients who had a primary procedure, whereas the rest were revisions. Mean EBL was 1,336 mL (98 mL/level, 31% estimated blood volume). There were three thromboembolic complications, including one pulmonary embolism and two deep vein thromboses (DVTs), which were all treated successfully with anticoagulation. There were no cases of myocardial infarction, seizure, stroke, or acute renal failure., Conclusions: This is the first study to demonstrate the use of high-dose TXA in a complex ASD population. Larger prospective studies are needed to assess the efficacy and safety of high-dose TXA in ASD., Level of Evidence: Level IV, therapeutic., (Copyright © 2017 Scoliosis Research Society. Published by Elsevier Inc. All rights reserved.)

Purpose: To describe hypercomplex pedicle subtraction osteotomies (HyC-PSO) for adult spine deformity with sagittal imbalance in terms of preoperative, intraoperative and postoperative outcomes and complications., Methods: From a prospective single centre database, patients undergoing PSO between January 2016 and May 2017 were reviewed. HyC-PSO were defined as those in patients with one of the following conditions: sagittal correction > 45° needed at a single level or at 1-3 consecutive vertebrae, more than 60° of total sagittal correction needed and PSO on segments of the spine with congenital deformities., Results: 22 patients were included, 14 had standard PSO (group A) and 8 had HyC-PSO (group B). Significant correction of lumbar lordosis (LL) and pelvic (PT) was noted in both groups (p < 0.01). Operative time was longer in HyC-PSO, 604 min compared to standard PSO, 478 min. A trend versus greater intraoperative blood loss (3837 vs 2285 ml) and greater intraoperative blood infusion (from cell saver plus homologous, 2306 vs 1280 ml) was recorded in HyC-PSO (ns). Patients in group B received significantly more blood units intra and postoperatively (8.25 vs 4.71 units, p = 0.006). Sagittal correction at the PSO level (54.7°-30° to 85°-vs 26.8°-8° to 39°-, p = 0.000) and total sagittal correction (64.5°-50 to 95°-vs 39.8°-20° to 51°-, p = 0.000) were greater in HyC-PSO. PROMs at the last available follow-up did not show significant differences between groups for any of the outcomes analyzed. Complications were similar in both groups., Conclusion: This is the first report on hypercomplex pedicle subtraction osteotomies. Hypercomplex PSO describes a subset of clinical scenarios with increased surgical effort that can be measured as longer surgical time and greater blood transfusion requirements. Successful correction of misalignment can be achieved in this specific group of patients, and clinical results and complications profile could be similar to standard PSO procedures.

Purpose: Biomechanical analysis of Ponte (PO) and pedicle subtraction osteotomies (PSO) in kyphotic deformity instrumentation., Methods: Patient-specific biomechanical model was used to computationally simulate seven hyperkyphotic instrumentation cases with three osteotomy strategies-1-level PSO, 3-level PO, or 6-level PO; forces within the instrumented spine were assessed and results were analyzed through rANOVA tests., Results: Corrections with multi-level PO were close to those with one-level PSO. In upright position, average implant forces were from 225 to 280 N and rod bending moments were around 10 Nm with no significant difference between the three strategies (p < 0.05). In simulations of 30° flexion, rod bending moments increased by 38, 2, and 8 %, implant forces increased by 28, 23 and 26 % for the 1-level PSO, 3-level PO, and 6-level PO, respectively. Correction per vertebral level was smaller than the maximum correction allowed by PO and PSO., Conclusions: Multi-level PO allows similar kyphotic correction to 1-level PSO in spinal deformities with mixed indications for PO and PSO. Loads on the instrumentation constructs in PSO were higher than multi-level PO and higher in 6-level PO than 3-level PO. High loads were located more on the osteotomy sites. The rod shape should be adapted to the anticipated spine correction on the osteotomy sites.

Background Context: Single pedicle subtraction osteotomy (PSO) has been used to correct ankylosing spondylitis (AS) kyphosis successfully, but this approach seems insufficient to correct severe kyphosis. Two-level PSO has been attempted to correct advanced kyphosis in recent years. However, studies have not yet compared outcomes between single and double PSOs, and the indications to perform two-level PSO are unclear., Purpose: This study aimed to compare the radiologic and clinical outcomes between single- and two-level PSOs in correcting AS kyphosis., Study Design: This work is a retrospective cohort study., Patient Sample: Sixty patients were included. Thirty-seven underwent single-level PSO, and 23 underwent one stage two-level PSO., Outcome Measures: The radiologic analysis included thoracic kyphosis, thoracolumbar junction, lumbar lordosis, pelvic index, chin-brow vertical angle (CBVA), sagittal vertical axis (SVA), and pelvic tilt (PT). Clinical assessment was performed with a Scoliosis Research Society-22 (SRS-22) outcomes instrument. The operative time, blood loss, and complications were also documented., Methods: All of the aforementioned measurements were recorded before surgery, after surgery, and at the last follow-up. The outcomes were compared between the two groups., Results: The operating time was 232±52 minutes for single- and 282±43 minutes for two-level PSOs. The blood loss was 1,240±542 mL (Level 1) and 2,202±737 mL (Level 2). The total spine correction was 43.2°±15.1° (Level 1) and 60.6°±19.1° (Level 2) (p<.001), the SVA correction was 13.2±10.6 cm (Level 1) and 23.6±10.2 cm (Level 2) (p<.001), and the PT correction was 10.1°±11.6° (Level 1) and 15.2°±10.8° (Level 2) (p<.001). The CBVA correction was 50.6°±17.8° (Level 1) and 51.4°±18.6° in (Level 2) (p>.05). All patients could walk with horizontal vision and lie on their backs postoperatively. The SRS-22 improved from 1.7±0.4 to 4.2±0.8 in the two-level group and 1.8±0.8 to 4.3±0.7 in the single-level group. The fusion of the osteotomy was achieved in each patient. The complications were similar in both groups., Conclusions: Pedicle subtraction osteotomy is an effective method to correct kyphosis with AS. Most patients can be successfully treated by single PSO. In severe patients, two-level PSO may be preferable because its correction ability is greater and spine curvature is better than that of single-level PSO. However, two-level PSO requires an increased operating time and results in increased blood loss. Nevertheless, the complications were similar between the two groups., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Pedicle subtraction osteotomy (PSO) is a surgical technique to restore lumbar lordosis in patients with rigid sagittal deformity. Herein, we report on outcomes of a surgical technique utilizing a 4-rod PSO with satellite rods. A retrospective study was performed for a cohort of patients who underwent 4-rod PSO revision surgery for sagittal deformity. Procedures were performed by one surgeon at 2 different academic centers between 2004–2018. Alignment outcomes and complications specifically for revision surgeries in previously fused spines were assessed. 40 patients underwent PSO with the satellite rod technique (n = 29 at L3, 72.5%; n = 7 at L4, 17.5%). Mean PSO angle was 28.7 ± 7.6°. Two patients (5%) had rod fracture necessitating revision surgery at 32 and 34 months. Three patients (7.5%) developed proximal junctional kyphosis (PJK), but none required revision. No patients developed pseudoarthrosis. Mean preoperative sagittal vertical axis (SVA) was 13.5 ± 7.3 cm, which decreased to 4.8 ± 7.3 cm (P = 0.002) postoperatively. Mean preoperative pelvic incidence-lumbar lordosis (PI-LL) mismatch improved from 35.9 ± 16.6° preoperatively to 11.8 ± 14.6° postoperatively (P < 0.001). Mean preoperative pelvic tilt (PT) improved from 34.7 ± 9.8° preoperatively to 30.1 ± 9.0° (P = 0.026) postoperatively. Mean global alignment and proportion (GAP) score improved from 10 ± 2 preoperatively to 8 ± 2 postoperatively (P < 0.001), which was still considered severely disproportioned. Rod failure rate after PSO with the 4-rod satellite configuration was low. SVA, PI-LL mismatch, and PT significantly improved for these previously-fused patients. Mean GAP score also improved, but was still considered severely disproportioned, likely due to the inability of PSO to correct low LL or PT in previously-fused spines. [ABSTRACT FROM AUTHOR]

Study Design: Finite element (FE) study. Objective: Pedicle subtraction osteotomy (PSO) is a surgical method to correct sagittal plane deformities. In this study, we aimed to investigate the biomechanical effects of lumbar disc degeneration on the instrumentation following PSO and assess the effects of using interbody spacers adjacent to the PSO level in a long instrumented spinal construct. Methods: A spinopelvic model (T10-pelvis) with PSO at the L3 level was used to generate 3 different simplified grades of degenerated lumbar discs (mild (Pfirrmann grade III), moderate (Pfirrmann grade IV), and severe (Pfirrmann grade V)). Instrumentation included eighteen pedicle screws and bilateral primary rods. To investigate the effect of interbody spacers, the model with normal disc height was modified to accommodate 2 interbody spacers adjacent to the PSO level through a lateral approach. For the models, the rods' stress distribution, PSO site force values, and the spine range of motion (ROM) were recorded. Results: The mildly, moderately, and severely degenerated models indicated approximately 10%, 26%, and 40% decrease in flexion/extension motion, respectively. Supplementing the instrumented spinopelvic PSO model using interbody spacers reduced the ROM by 22%, 21%, 4%, and 11% in flexion, extension, lateral bending, and axial rotation, respectively. The FE results illustrated lower von Mises stress on the rods and higher forces at the PSO site at higher degeneration grades and while using the interbody spacers. Conclusions: Larger and less degenerated discs adjacent to the PSO site may warrant consideration for interbody cage instrumentation to decrease the risk of rod fracture and PSO site non-union. [ABSTRACT FROM AUTHOR]

Since its proposal, the Global Alignment and Proportion (GAP) score has been the topic of several external validation studies, which have yielded conflicting results. Given the lack of consensus regarding this prognostic tool, the authors aim to assess the accuracy of GAP scores for predicting mechanical complications following adult spinal deformity correction surgery. A systematic search was performed using PubMed, Embase, and Cochrane Library for the purpose of identifying all studies evaluating the GAP score as a predictive tool for mechanical complications. GAP scores were pooled using a random-effects model to compare patients reporting mechanical complications after surgery versus those reporting no complications. Where receiver operator curves were provided, the area under the curve (AUC) was pooled. A total of 15 studies featuring 2092 patients were selected for inclusion. Qualitative analysis using Newcastle-Ottawa criteria revealed moderate quality among all included studies (5.99/9). With respect to sex, the cohort was predominantly female (82%). The pooled mean age among all patients in the cohort was 58.55 years, with a mean follow-up of 33.86 months after surgery. Upon pooled analysis, we found that mechanical complications were associated with higher mean GAP scores, albeit minimal (mean difference = 0.571 [ 95% confidence interval: 0.163–0.979]; P = 0.006, n = 864). Additionally, age (P = 0.136, n = 202), fusion levels (P = 0.207, n = 358), and body mass index (P = 0.616, n = 350) were unassociated with mechanical complications. Pooled AUC revealed poor discrimination overall (AUC = 0.69; n = 1206). GAP scores may have a minimal-to-moderate predictive capability for mechanical complications associated with adult spinal deformity correction. [ABSTRACT FROM AUTHOR]

INTRODUCTION: Classical instrumentation may be insufficient in the surgical treatment of rigid spinal deformities with structural changes in bone tissue. Many different types of osteotomy have been described to correct such rigid deformities. In this study, we aimed to evaluate the clinical and radiological results of pedicle subtraction osteotomy (PSO) applied at the thoracic level in patients with coronal and/or sagittal plane spinal deformity. METHODS: 61 of the 123 cases, who underwent PSO for spinal deformity between 2010 and 2013, were included in the study. Pre- and post-operative ortho-radiography was performed; angles (scoliosis, kyphosis, and lordosis angles) and global sagittal balance were measured. Duration of operation, bleeding and complications were noted. SF-36 scoring was used for clinical outcome. RESULTS: This study was consist of 30 male and 31 female patients including 28 scoliosis, 23 kyphosis and 10 ankylosing spondylitis cases. Post-operative mean Cobb angle was 62%, sagittal balance was 42%, kyphosis angle was 38%, thoracic kyphosis angle was 61%, and lordosis angle was 19.44% corrected (p

Purpose: This study aimed to evaluate the clinical and radiological outcomes of two patient groups with congenital kyphosis and kyphoscoliosis who underwent posterior surgical correction using Schwab grade 3–4 and Schwab grade 5–6 osteotomies.A retrospective analysis was conducted on 58 patients (35 females and 23 males; mean age: 16.2 yr). Radiological evaluations included preoperative,postoperative,and last follow-up measurements of segmental kyphosis, scoliosis, lumbar lordosis(LL), C7-central sacral vertical line[C7-CSVL] and sagittal vertical axis [SVA], and pelvic parameters (pelvic incidence [PI],pelvic tilt [PT], sacral slope [SS].Clinical evaluations included Scoliosis Research Society-22r (SRS-22r) scores and Oswestry Disability Index (ODI) scores at preoperative and last follow-up time points.The mean deformity correction was 53.4%. Preoperative segmental kyphosis angles for Schwab grade 3–4 osteotomy (group 1) and Schwab grade 5–6 osteotomy (group 2) were 66.9° and 104.9°, respectively.The last follow-up angles were 33.1° and 48.2° (p < 0.001).No significant loss of correction was observed in either group (p > 0.05). SRS-22r scores improved significantly at the last follow-up (p < 0.001).Similarly, ODI scores improved significantly in both groups (p < 0.001).Neurological complications occurred in 14 (24.1%) patients,including dura injury, spinal nerve root injury, transient incomplete neurological deficits, and spinal cord compression.Mechanical complications were reported in 14 (24.1%) patients and included rod fractures, proximal junction kyphosis, pedicle screw malposition, and pedicle screw loosening.Posterior surgical correction using Schwab grade 3–4 and Schwab grade 5–6 osteotomies yields satisfactory radiological and clinical outcomes in patients with congenital kyphosis and kyphoscoliosis. However, higher osteotomy grades, necessitated by greater deformity severity, are associated with increased complication rates.Methods: This study aimed to evaluate the clinical and radiological outcomes of two patient groups with congenital kyphosis and kyphoscoliosis who underwent posterior surgical correction using Schwab grade 3–4 and Schwab grade 5–6 osteotomies.A retrospective analysis was conducted on 58 patients (35 females and 23 males; mean age: 16.2 yr). Radiological evaluations included preoperative,postoperative,and last follow-up measurements of segmental kyphosis, scoliosis, lumbar lordosis(LL), C7-central sacral vertical line[C7-CSVL] and sagittal vertical axis [SVA], and pelvic parameters (pelvic incidence [PI],pelvic tilt [PT], sacral slope [SS].Clinical evaluations included Scoliosis Research Society-22r (SRS-22r) scores and Oswestry Disability Index (ODI) scores at preoperative and last follow-up time points.The mean deformity correction was 53.4%. Preoperative segmental kyphosis angles for Schwab grade 3–4 osteotomy (group 1) and Schwab grade 5–6 osteotomy (group 2) were 66.9° and 104.9°, respectively.The last follow-up angles were 33.1° and 48.2° (p < 0.001).No significant loss of correction was observed in either group (p > 0.05). SRS-22r scores improved significantly at the last follow-up (p < 0.001).Similarly, ODI scores improved significantly in both groups (p < 0.001).Neurological complications occurred in 14 (24.1%) patients,including dura injury, spinal nerve root injury, transient incomplete neurological deficits, and spinal cord compression.Mechanical complications were reported in 14 (24.1%) patients and included rod fractures, proximal junction kyphosis, pedicle screw malposition, and pedicle screw loosening.Posterior surgical correction using Schwab grade 3–4 and Schwab grade 5–6 osteotomies yields satisfactory radiological and clinical outcomes in patients with congenital kyphosis and kyphoscoliosis. However, higher osteotomy grades, necessitated by greater deformity severity, are associated with increased complication rates.Results: This study aimed to evaluate the clinical and radiological outcomes of two patient groups with congenital kyphosis and kyphoscoliosis who underwent posterior surgical correction using Schwab grade 3–4 and Schwab grade 5–6 osteotomies.A retrospective analysis was conducted on 58 patients (35 females and 23 males; mean age: 16.2 yr). Radiological evaluations included preoperative,postoperative,and last follow-up measurements of segmental kyphosis, scoliosis, lumbar lordosis(LL), C7-central sacral vertical line[C7-CSVL] and sagittal vertical axis [SVA], and pelvic parameters (pelvic incidence [PI],pelvic tilt [PT], sacral slope [SS].Clinical evaluations included Scoliosis Research Society-22r (SRS-22r) scores and Oswestry Disability Index (ODI) scores at preoperative and last follow-up time points.The mean deformity correction was 53.4%. Preoperative segmental kyphosis angles for Schwab grade 3–4 osteotomy (group 1) and Schwab grade 5–6 osteotomy (group 2) were 66.9° and 104.9°, respectively.The last follow-up angles were 33.1° and 48.2° (p < 0.001).No significant loss of correction was observed in either group (p > 0.05). SRS-22r scores improved significantly at the last follow-up (p < 0.001).Similarly, ODI scores improved significantly in both groups (p < 0.001).Neurological complications occurred in 14 (24.1%) patients,including dura injury, spinal nerve root injury, transient incomplete neurological deficits, and spinal cord compression.Mechanical complications were reported in 14 (24.1%) patients and included rod fractures, proximal junction kyphosis, pedicle screw malposition, and pedicle screw loosening.Posterior surgical correction using Schwab grade 3–4 and Schwab grade 5–6 osteotomies yields satisfactory radiological and clinical outcomes in patients with congenital kyphosis and kyphoscoliosis. However, higher osteotomy grades, necessitated by greater deformity severity, are associated with increased complication rates.Conclusion: This study aimed to evaluate the clinical and radiological outcomes of two patient groups with congenital kyphosis and kyphoscoliosis who underwent posterior surgical correction using Schwab grade 3–4 and Schwab grade 5–6 osteotomies.A retrospective analysis was conducted on 58 patients (35 females and 23 males; mean age: 16.2 yr). Radiological evaluations included preoperative,postoperative,and last follow-up measurements of segmental kyphosis, scoliosis, lumbar lordosis(LL), C7-central sacral vertical line[C7-CSVL] and sagittal vertical axis [SVA], and pelvic parameters (pelvic incidence [PI],pelvic tilt [PT], sacral slope [SS].Clinical evaluations included Scoliosis Research Society-22r (SRS-22r) scores and Oswestry Disability Index (ODI) scores at preoperative and last follow-up time points.The mean deformity correction was 53.4%. Preoperative segmental kyphosis angles for Schwab grade 3–4 osteotomy (group 1) and Schwab grade 5–6 osteotomy (group 2) were 66.9° and 104.9°, respectively.The last follow-up angles were 33.1° and 48.2° (p < 0.001).No significant loss of correction was observed in either group (p > 0.05). SRS-22r scores improved significantly at the last follow-up (p < 0.001).Similarly, ODI scores improved significantly in both groups (p < 0.001).Neurological complications occurred in 14 (24.1%) patients,including dura injury, spinal nerve root injury, transient incomplete neurological deficits, and spinal cord compression.Mechanical complications were reported in 14 (24.1%) patients and included rod fractures, proximal junction kyphosis, pedicle screw malposition, and pedicle screw loosening.Posterior surgical correction using Schwab grade 3–4 and Schwab grade 5–6 osteotomies yields satisfactory radiological and clinical outcomes in patients with congenital kyphosis and kyphoscoliosis. However, higher osteotomy grades, necessitated by greater deformity severity, are associated with increased complication rates. [ABSTRACT FROM AUTHOR]

Copyright of Bosphorus Medical Journal / Boğaziçi Tıp Dergisi is the property of KARE Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Although the utility of patient-specific instruments (PSI) has been well established for complex osteotomies in orthopedic surgery, it is yet to be comparatively analyzed for complex spinal deformity correction, such as pedicle subtraction osteotomy (PSO). Methods: Six thoracolumbar human cadavers were used to perform nine PSOs using the free-hand (FH) technique and nine with PSI (in total 18 PSOs). Osteotomy planes were planned on the basis of preoperative computed tomography (CT). A closing-wedge angle of 30° was targeted for each PSO. Postoperative CT scans were obtained to measure segmental lordosis correction and the deviation from the planned 30° correction as well as the osseous gap of posterior elements. Results: The time required to perform a PSO was 18:22 (range 10:22–26:38) min and 14:14 (range 10:13–22:16) min in the PSI and FH groups, respectively (p = 0.489). The PSI group had a significantly higher lordosis gain (29°, range 23–31° vs. 21°, range 13–34°; p = 0.015). The lordosis gain was significantly more accurate with PSI (deviation angle: 1°; range 0–7°) than with the FH technique (9°; range 4–17°; p = 0.003). PSI achieved a significantly smaller residual osseous gap of the posterior elements (5 mm; range 0–9 mm) than the FH group (11 mm; range 3–27 mm; p = 0.043).With PSI, an angular difference of 3° (range 1–12°), a translational offset of 1 (range 0–6) mm at the level of the lamina, and a vertebral body entry point deviation of 1 (range 0–4) mm was achieved in the osteotomies. Conclusions: PSI-guided PSO can be a more feasible and accurate approach in achieving a planned lordosis angle than the traditional FH technique in a cadaver model. This approach further reduced osseous gaps, potentially promoting higher fusion rates in vivo.

Purpose: We present the case of a 69-year-old female patient that suffered double major complication in revision spine surgery. Methods: The patient had to undergo several spine surgeries due to degenerative disorder and adjacent segment disease. After long segment fusion surgery, the patient developed proximal junctional failure with severe thoracic myelopathy. The goal of our revision surgery was to perform a spinal canal clearance in the stenotic thoracic region and to restore the global spine balance by pedicle subtraction osteotomy (PSO) in the fused flat-back lumbar spine. Results: During the PSO closing procedure, we recognized a complete vertebral column dissociation a level above the PSO. This was caused by a tear-off of the intervertebral cage in the prefused lumbar spine. As we were not able to close the osteotomy wedge, we decided to perform a staged anterior column support using an expandable cage. Immediately after the primary posterior surgery, the patient presented a complete paraplegia. Emergency revision did not reveal myelon compression. The anterior spine surgery was done four days later. We transferred the patient to neurological rehab. The patient recovered well, the paraplegia was regressive. The radiological follow-up showed a balanced spine without adjacent segment disease and implant problems. Conclusion: Revision spine surgery is technically demanding. The complication rate is high. The concept of spinopelvic balance is mandatory in long segment fusion surgery to prevent junctional failures, adjacent segment disease, and neurological problems.

Study Design: A 2-year follow-up review of 62 patients with severe rigid scoliosis (>120°).Objective: To evaluate the effectiveness and safety of halo-pelvic traction (HPT) for treating severe rigid scoliosis (>120°).Summary Of Background Data: Severe rigid scoliosis (>120°) is still a challenge for spine surgeons. A combination of presurgical HPT traction, osteotomy, and internal fixation could be a safe and effective solution for these cases.Methods: We reviewed the records of all the patients with severe rigid scoliosis (>120°) treated with presurgical HPT from 2013 through 2017. Radiographic measurements were performed. The period of traction, estimated blood loss, operation time, complications, and bed rest period were recorded.Results: A total of 62 patients who had 2-year radiological follow-up were included in the study. In 30 patients, vertebral column resection (VCR) was performed aiming to achieve a better correction rate. In patients who received a VCR, the average preoperative Cobb angle was 133.6°, and the average correction rate at 2 years after surgery was 65.4%. Compared with the average height before treatment, at 2 years after surgery the average height was 12.5 cm greater. In patients who did NOT received VCR, the average preoperative Cobb angle was 131.5°, and the average correction rate at 2 years after surgery was 64.1%. Compared with the average height before treatment, at 2 years after surgery the average height was 14.0 cm greater. Common complications during HPT included infected pelvic pins, brachial plexus palsy, and weakness of the lower extremities. No patients experienced permanent neurological deficits or death.Conclusion: For severe rigid scoliosis with a Cobb angle greater than 120°, a combination of short-term presurgical HPT and posterior surgery is an effective and safe solution. After 4 to 6 weeks of presurgical HPT the Cobb angle can be decreased by approximately 50%, providing a favorable condition for spine corrective surgery.Level of Evidence: 3. [ABSTRACT FROM AUTHOR]

Adult cervical deformity (ACD) has been shown to have a substantial impact on quality of life and overall health, with moderate to severe deformities resulting in significant disability and dysfunction. Fortunately, surgical management and correction of cervical sagittal imbalance can offer significant benefits and improvement in pain and disability. ACD is a heterogenous disease and specific surgical correction strategies should reflect deformity type (driver of deformity) and patient-related factors. Spinal rigidity is one of the most important considerations as soft tissue releases and osteotomies play a crucial role in cervical deformity correction. For ankylosed, fixed, and severe deformity, 3-column osteotomy (3CO) is often warranted. A 3CO can be done through combined anteriorposterior (vertebral body resection) and posterior-only approaches (open or closed wedge pedicle subtraction osteotomies [PSOs]). This article reviews the literature for currently published studies that report results on the use of 3CO for ACD, with a special concentration on posterior based 3CO (open and closed wedge PSO). More specifically, this review discusses the indications, radiographic corrective ability, and associated complications. [ABSTRACT FROM AUTHOR]

• We aim to investigate the effects of cross-link position on rod stress in lumbar pedicle subtraction osteotomy (PSO) site by using finite element model (FEM). • The geometry and dimensions of FEM were obtained from a high-resolution computed tomography scan data of a 65 years old female patient with spinal sagittal imbalance. • The peak von mises stress (PVMS) of rod at PSO site decreased as the cross-link is located apart from the PSO site during flexion and extension. • Cross-link at two levels apart from the PSO site does not increase the risk of rod fracture. The purpose of this study is to investigate the effect of the cross-link position on the rod fracture phenomenon during pedicle subtraction osteotomy (PSO) surgery using finite element model (FEM). A three-dimensional finite element model of a lumbar spine with sagittal imbalance was constructed using computed tomography data of a 65-year-old female patient. After simulating the standard PSO at the L4 level, we constructed four models, specifically a model without a cross-link and three models with a cross-link at three different sites. The peak von Mises stress (PVMS) of the rod around the PSO site was measured after applying physiological loads (flexion, extension, axial rotation, and lateral bending) in each model. The measured PVMS outcomes at the PSO site were 135.8, 135.9, 208.9, and 384.7 MPa for model 1, 2, 3, and 4 during flexion, and 180.0, 180.1, 210.1, and 445.7 MPa during extension. These results show that when the cross-link is located at the PSO site, the rod stress at the PSO site increases significantly during flexion and extension. As the cross-link moved away from the PSO site, the effect on the rod stress decreased. When the cross-link was placed two levels away from the PSO site, the rod stress was scarcely affected. When the cross-link during PSO surgery was positioned two levels away from the PSO site, the risk of rod fracture did not increase. [ABSTRACT FROM AUTHOR]

To compare the treatment results between 1-level vertebral column decancellation (VCD) and pedicle subtraction osteotomy (PSO) for correcting severe kyphotic deformity in ankylosing spondylitis (AS). VCD and PSO have been used to correct AS-related kyphotic deformity, but the differences on correcting results between VCD and PSO are not clear. Between 2013 and 2015, 57 patients underwent 1-level spinal osteotomy (VCD: n = 30; PSO: n = 27) for correcting kyphotic deformity. Sagittal parameters, fusion results, surgical information, and clinical outcomes were documented and compared. All data were obtained before and 1 week after surgery, 6 months after surgery, and at final follow-up (at least 2 years). VCD provided significantly greater osteotomy angle (50.8° ± 9.7°) than PSO (38.5° ± 6.1°). In the VCD group, the change of the anterior column was 5.0 ± 1.3 mm, which was larger than the PSO group. The middle column was shortened by 9.9 ± 2.0 mm and 19.1 ± 3.3 mm in the VCD group and PSO group, respectively. There was no significant difference in operating time and blood loss between the 2 groups. All cases had solid fusion. Between the 2 groups, Scoliosis Research Society Outcomes Instrument-22 scores were similar at the final follow-up. No major acute complications occurred in both groups. VCD is a safe and effective method in treating rigid kyphotic deformity secondary to AS. VCD provides a larger correction angle in one segment and preserves more height of osteotomized vertebrae than PSO. [ABSTRACT FROM AUTHOR]

Background Context: Pedicle subtraction osteotomy (PSO) is a challenging restoration technique for sagittal imbalance and is associated with significant complications. One of the major complications is rod fracture and there exists a need for a biomechanical assessment of this complication for various instrumentation configurations.Purpose: To evaluate and compare the global range of motion (ROM), rod stress distribution, and the forces on the pedicle subtraction site in various instrumentation configurations using finite element analysis.Study Design/setting: A computational biomechanical analysis.Methods: A previously validated osseoligamentous three-dimensional spinopelvic finite element model (T10-pelvis) was used to develop a 30° PSO at the L3 level. In addition to the standard bilateral cobalt chromium primary rod instrumentation of the PSO model, various multirod configurations including constructs with medially, laterally, and posteriorly affixed satellite rods and the short-rod technique were assessed in spinal physiological motions. T10-S1 global ROM, maximum von Mises stress on the rods and at the PSO level, factor of safety (yield stress of the rod material/maximum actual stress in the rod) and the load acting across the PSO site were compared between various instrumentation configurations. The higher the factor of safety the lesser the chances of rod failure.Results: Among all multirod constructs, posteriorly affixed satellite rod construct showed the greatest motion reduction compared to the standard bilateral rod configuration followed by medially and laterally affixed satellite rod constructs. Compared to the standard bilateral rod configuration, recessed short-rod technique resulted in 4% to 49% reduction in T10-S1 ROM recorded in extension and lateral bending motions, respectively, while the axial rotation motion increased by approximately 31%. Considering the maximum stress values on the rods, the recessed short-rod technique showed the greatest factor of safety (FOS = 4.1) followed by posteriorly (FOS = 3.9), medially (FOS = 3), laterally affixed satellite rod constructs (FOS = 2.8), and finally the standard bilateral rod construct (FOS = 2.7). By adding satellite rods, the maximum von Mises stress at the PSO level of the rods also reduced significantly and at this level resulted in the greatest FOS in the posteriorly affixed satellite rod construct. Compared to the standard bilateral rod construct, the load magnitude acting on the osteotomy site decreased by 11%, 16%, and 37% in the laterally, medially, and posteriorly affixed satellite rod constructs, respectively, and did not change with the short-rod technique.Conclusions: Adding satellite rods increases the rigidity of the construct, which results in an increase in the stability and the reduction of the global ROM. Additionally, having satellite rods reduces the stress on the primary rods at the PSO level and shifts the stresses from this PSO region to areas adjacent to the side-by-side connectors. The data suggest a significant benefit in supplementing medial over lateral satellite rods at the PSO by reducing stress on the primary rods. Except the recessed short-rod technique, all other multirod constructs decrease the magnitude of the load acting across the osteotomy region, which could cause a delayed or non-union at the PSO site.Clinical Significance: The study evaluates the mechanical performance of various satellite rod instrumentation configurations following PSO to predict the risk factors for rod fracture and thereby mitigate the rate of clinically relevant failures. [ABSTRACT FROM AUTHOR]

Purpose: To review the incidence of perioperative and late complications of surgery for spinal deformity (ASD).Methods: Review of the literature. We reviewed recent literature in English to investigate the incidence of complications in ASD surgery in the perioperative (≤ 3 months post-operative) and late (> 3 months post-operative) periods. Randomized-controlled trials, non-randomized trials, cohort studies, case-control studies, and case series published in 2005 or later were included. We divided articles according to surgical technique: open procedures (OP), minimally invasive surgery (MIS), and hybrid procedures (HP). Complications were recorded, grouped by surgical technique, and then classified according to a proposed Grading of Incidence of Complications (IOC).Results: Ninety-six publications reporting on 12,168 patients were included; 68 were level IV of evidence studies, 24 were level III, and 4 level II. Perioperative IOC was 26.5% in OP, 36.4% in HP, and 24.2% in MIS. Late IOC was 11.1% in OP, 15.4% in HP, and 14.0% in MIS. IOC was significantly higher for hybrid procedures compared to both open and MIS procedures.Conclusions: Reported complications of surgery for ASD in the recent literature are frequent (24-36% perioperative plus 11-15% late). Open procedures were the most extensively reported in the literature. Complication rates are similar for OP and MIS. HP presented higher IOC likely due to the combination of OP and MIS respective complications. Small number of studies and heterogeneity in reporting could result in risk of bias in these results. Large-scale registry-based studies can fill this gap in the future. These slides can be retrieved under Electronic Supplementary Material. [ABSTRACT FROM AUTHOR]

Background Context: Sagittal translation, a potential complication of pedicle subtraction osteotomy (PSO), can result in neurologic damage. However, few studies have been conducted on sagittal translation and its risk factors after PSO in patients with ankylosing spondylitis (AS).Purpose: We aimed to report cases of sagittal translation that developed after PSO in patients with AS with kyphotic deformity and to analyze risk factors for sagittal translation.Study Design: A retrospective case-control study was carried out.Patient Sample: This study included 53 patients (58 cases) with AS who underwent PSO to correct their kyphotic deformity.Outcome Measures: The modified Stoke Ankylosing Spondylitis Spine Score (mSASSS) was measured before the surgery. Radiological pelvic and sagittal parameters were also measured before and after surgery. Developments of sagittal translation were confirmed with intraoperative radiograph.Methods: The subjects were grouped according to the presence (ST group) and absence (non-ST group) of sagittal translation. The demographic and radiological parameters were compared between two groups. Through multivariate logistic regression analysis, the correlations between sagittal translation and relevant parameters were analyzed for risk factor evaluation.Results: Sagittal translation developed in 16 patients (30.2%) [16 cases (27.6%)]. The mean lumbar lordosis angle and sagittal vertical axis of both ST group and non-ST group were successfully corrected. In a comparison of two groups, the ST group (58.2±13.3) showed a significantly higher mSASSS than the non-ST group (33.9±11.9) (p<.001). The ST group (50.4°±7.8°, 16.9°±6.8°) also showed a significantly higher preoperative pelvic incidence and sacral slope than the non-ST group (45.3°±7.2°, 11.0°±7.7°) (p=.026, p=.011). No significant differences were observed between the two groups for the rest of radiological parameters. In multivariate analysis, only mSASSS was positively correlated with sagittal translation (odds ratio 1.16, p=.001).Conclusion: The incidence of sagittal translation after PSO was closely related with severity of ankylosis in patients with AS. Therefore, surgeons must consider sagittal translation, which could induce neurologic complications, when PSO is performed for patients with AS with severe ankylosis. [ABSTRACT FROM AUTHOR]

Purpose: Pedicle subtraction osteotomy (PSO) is performed to treat rigid, sagittal spinal deformities, but high rates of implant failure are reported. Anterior lumbar interbody fusion has been proposed to reduce this risk, but biomechanical investigation is lacking. The goal of this study was to quantify the (1) destabilizing effects of a lumbar osteotomy and (2) contribution of anterior lumbar interbody fusion (ALIF) at the lumbosacral junction as recommended in literature.Methods: Fourteen fresh human thoracolumbosacral spines (T12-S1) were tested in flexion-extension (FE), lateral bending (LB), and axial rotation (AR). Bilateral pedicle screws/rods (BPS) were inserted at T12-S1, cross connectors (CC) at T12-L1 and L5-S1, and anterior interbody spacers (S) at L4-5 and L5-S1. In one group, PSO was performed in seven specimens at L3. All specimens were sequentially tested in (1) Intact; (2) BPS; (3) BPS + CC; (4) BPS + S; and (5) BPS + S + CC; a second group of seven spines were tested in the same sequence without PSO. Mixed-model ANOVA with repeated measures was performed (p ≤ 0.05).Results: At the osteotomy site (L2-L4), in FE, BPS, BPS + CC, BPS + S, BPS + CC + S reduced motion to 11.2, 12.9, 10.9, and 11.4%, respectively, with significance only found in BPS and BPS + S construction (p ≤ 0.05). All constructs significantly reduced motion across L2-L4 in the absence of PSO, across all loading modes (p ≤ 0.05). PSO significantly destabilized L2-L4 axial rotational stability, regardless of operative construction (p ≤ 0.05). Across L4-S1 and L2-S1, all instrumented constructs significantly reduced motion, in both PSO- and non-PSO groups, during all loading modes (p ≤ 0.05).Conclusions: These findings suggest anterior interbody fusion minimally immobilizes motion segments, and interbody devices may primarily act to maintain disc height. Additionally, lumbar osteotomy destabilizes axial rotational stability at the osteotomy site, potentially further increasing mechanical demand on posterior instrumentation. Clinical studies are needed to assess the impact of this treatment strategy. [ABSTRACT FROM AUTHOR]

The correction of rigid spinal deformities in adult patients can require a three-column osteotomy (pedicle subtraction osteotomy [PSO] or vertebral column resection [VCR]) to obtain spinal balance. Unfortunately, the existing adult deformity literature frequently reports the outcomes and complications of these procedures together even though VCR is a more extensive procedure with potentially higher rates of complications. We sought to address this shortcoming and provide clinicians with an overview of the existing literature regarding VCR in adult patients. The goals of this review are: to determine the rate of overall and neurologic complications following VCR, the rate of complications with VCR compared to PSO, and the impact of VCR on clinical and radiographic outcomes. An electronic literature search was used to identify studies reporting outcomes or complications following VCR in adult patients. Raw data on patient demographics, case information, radiographic outcomes, complications and clinical outcomes were extracted. Data were pooled to report a rate of overall complications and neurologic complications. A pooled relative risk of complications following PSO vs. VCR was also calculated. Eleven retrospective studies (Level IV) met our inclusion criteria. The overall rate of complications was 69.2%. The reoperation rate was 9.6%. The rate of neurologic complications was 13.3% (range, 6.3% to 15.8%) with most cases being transient. The rate of permanent neurologic deficits was 2.0%. We found a significantly higher rate of all complications with VCR compared to PSO (relative risk, 1.36; 95% confidence interval, 1.24-1.49; p <0.001). All studies reporting clinical outcomes showed significant improvements in functional outcome postoperatively. [ABSTRACT FROM AUTHOR]

Study design: A retrospective clinical study. Objective: To evaluate the outcomes of two-level (T12 and L3) pedicle subtraction osteotomy (PSO) for severe thoracolumbar kyphosis in ankylosing spondylitis (AS), and to discuss the surgical strategies of this surgery. Background: Cases were limited on the results of two-level PSO for correction of severe kyphosis caused by AS, nor on surgical strategies of this type of surgery. Methods: From March 2006 to December 2010, nine consecutive AS patients with severe kyphotic deformity, underwent T12 and L3 PSOs. Chin-brow vertical angle (CBVA) and radiographic assessments which contain thoracic kyphosis (TK), lumbar lordosis (LL), global kyphosis (GK), and sagittal vertical axis were carefully recorded pre and postoperatively to evaluate the sagittal balance. Intra and postoperative complications were also registered. All patients were asked to fill out Oswestry Disability Index before surgery and at the last follow-up visit. Results: All nine patients (8M/1F), averaged 41.4 years old (range 35-51 years), were received two-level (T12 and L3) PSO, and were followed up after surgery for a mean of 39.9 months (range 24-68 months). Good cosmetic results were achieved in all patients. Mean correction at two-level PSO was 67.9 ± 5.5°. All CBVA, TK, LL, and GK were changed significantly after surgery ( P < 0.05), the mean amount of correction of which were 59.5 ± 13.8, 34.7 ± 3.8, 33.2 ± 2.4, and 54.0 ± 14.8 degrees, respectively, and with a small loss of correction at the last follow-up visit. Sagittal imbalance was significantly improved from 27.3 ± 4.4 to 3.4 ± 0.7 cm postoperatively. Neither mortalities nor any major neurological complications were found. The mean ODI score was significantly improved from 53.4 ± 15.5 before surgery to 8.2 ± 4.7 at the last visit. Conclusion: The outcomes of follow-up showed that two-level (T12 and L3) PSO can effectively and safely correct severe thoracolumbar kyphosis in AS. [ABSTRACT FROM AUTHOR]

Background: Patients with previous multilevel spinal fusion may require extension of the fusion to the sacro-pelvis. Our objective was to evaluate the outcomes and complications of these patients, stratified based on whether the revision was performed using a posterior-only spinal fusion (PSF) or combined anterior-posterior spinal fusion (APSF). Methods: A retrospective, multicenter evaluation of adults (>18 years old) with a history of prior spinal fusion for scoliosis (≥4 levels) terminating in the distal lumbar spine requiring extension of fusion to the sacro-pelvis (including iliac fixation in all cases), with minimum 2-year follow-up, was performed. Patients were stratified based on approach (APSF vs. PSF) and inclusion of pedicle subtraction osteotomy (PSO). The PSF group included patients treated with an anterior interbody fusion done through a posterior approach, whereas patients in the APSF group all had both anterior and posterior surgical approaches. Clinical outcomes were based on the Scoliosis Research Society (SRS-22) questionnaire. Results: Between 1995 and 2006, 45 patients (mean age = 49 years) met inclusion criteria, with a mean follow-up of 41.9 months (range 24 to 135 months). Demographic, preoperative, operative, and postoperative radiographic, SRS-22, and follow-up results were similar between APSF (n = 30) and PSF (n = 15) groups. The APSF group had more complications (13 of 30 vs. 3 of 15) and a greater number of pseudarthrosis (4 of 30 vs. 0 of 15) than the PSF group; however, these differences did not reach statistical significance. Patients treated with a PSO (n = 13) had greater sagittal vertical axis correction (7.7 cm vs. 2.2 cm; P = .04) compared with patients not treated with a PSO (n = 32). There were no differences in complication rates or follow-up SRS-22 scores based on whether a PSO was performed (P > .05). Conclusions: Among adults with previously treated scoliosis requiring extension to the sacro-pelvis, PSF produced radiographic fusion and clinical outcomes equivalent to APSF, whereas complication rates may be lower. PSO resulted in greater sagittal plane correction, without an increase in overall complication rates. [Copyright &y& Elsevier]

The article discusses a study on the risk factors for major complications in 3-column osteotomies and determine whether a major complication affects ultimate clinical outcomes, conducted by Joshua D. Auerbach et al. 240 consecutive pedicle subtraction osteotomy (PSO) and vertebral column resection (VCR) procedures in 237 patients were done at an institution between 1995 and 2008. At the end of the research, major complications occurred in 35% of 3-column osteotomies.

The article discusses a study a theory that formulas that integrate pelvic measures and account for dynamic changes in the pelvis and unfused spine accurately predict optimal postoperative sagittal alignment (SA). A retrospective analysis of patients with adult spinal deformity (ASD) treated with single-pedicle subtraction osteotomy (PSO) was conducted. It suggests that the reported formulas by V. Lafage et al had the greatest accuracy in predicting postoperative SVA after PSO surgery.

Abstract: Background context: The C7 plumb line method oversimplifies the true complexity of the spine. In a previous study, we mathematically modeled the normal spine using the spline function, enabling quantification of previously undescribed measurements such as area under the curve (AUC) and average sagittal position. The spine in fixed sagittal imbalance and the results of surgical correction have not been studied in a similar manner. Purpose: To quantitatively evaluate changes in spinal conformation in patients who underwent pedicle subtraction osteotomy (PSO) using measures derived from the spline model and to correlate these changes with functional outcome. Study design: Application of a mathematical model to a cohort of patients who underwent deformity surgery. Patient sample: Thirty-four consecutive patients with fixed sagittal imbalance who underwent PSO from 2001 to 2003. Outcome measures: Preoperative and postoperative 22-item Scoliosis Research Society (SRS-22) Outcomes Questionnaire scores were used for functional assessment. Methods: Radiographs of the 34 patients who underwent thoracic or lumbar PSO with at least 2 years of follow-up were examined at three time points. The posterosuperior aspect of each vertebral body was chosen as a representative point for the spinal sagittal curve. A cubic spline function was derived from these points. From this function, the AUCs and average sagittal positions of the thoracic, lumbar, and thoracolumbar segments were calculated. Results: The average sagittal position does not overlap the C7 plumb line in deformity patients, but is a much more stable measure. In the lumbar PSO cohort, the lumbar AUC and average sagittal position were not significantly different among normal, preoperative, and postoperative groups. The thoracic and thoracolumbar AUCs and average sagittal positions were dramatically more positive in the preoperative cohort compared with normals; these values significantly decreased toward neutrality after lumbar PSO, but remained abnormal. In the thoracic PSO cohort, the lumbar, thoracic, and thoracolumbar AUCs and average sagittal positions were not significantly different among normal, preoperative, and postoperative groups. The changes in thoracolumbar AUC and average sagittal position were better predictors of the SRS-22 total score than the change in C7 plumb line. Conclusions: The average sagittal position more comprehensively captures the nuances of a nonlinear spinal curve. Subcurve analysis enabled by the spline model is particularly helpful in assessing deformity and surgical correction on a segmental level. Increased sensitivity to the nuances of the spinal curve in this model results in superior correlation with clinical outcomes when compared with the C7 plumb line. We feel that a critical examination of the spinal curve will lead to improved understanding of deformity and planning for an optimal correction. [Copyright &y& Elsevier]

Author experience and literature review.To investigate and discuss decision-making on when to perform a Smith-Petersen osteotomy as opposed to a pedicle subtraction procedure and/or a vertebral column resection.Articles have been published regarding Smith-Petersen osteotomies, pedicle subtraction procedures, and vertebral column resections. Expectations and complications have been reviewed. However, decision-making regarding which of the 3 procedures is most useful for a particular spinal deformity case is not clearly investigated.Discussed in this manuscript is the author’s experience and the literature regarding the operative options for a fixed coronal or sagittal deformity.There are roles for Smith-Petersen osteotomy, pedicle subtraction, and vertebral column resection. Each has specific applications and potential complications.As the magnitude of resection increases, the ability to correct deformity improves, but also the risk of complication increases. Therein, an understanding of potential applications and complications is helpful. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]