Aims. To determine the major risk factors for unplanned reoperations (UROs) following corrective surgery for adult spinal deformity (ASD) and their interactions, using machine learning-based prediction algorithms and game theory. Methods. Patients who underwent surgery for ASD, with a minimum of two-year follow-up, were retrospectively reviewed. In total, 210 patients were included and randomly allocated into training (70% of the sample size) and test (the remaining 30%) sets to develop the machine learning algorithm. Risk factors were included in the analysis, along with clinical characteristics and parameters acquired through diagnostic radiology. Results. Overall, 152 patients without and 58 with a history of surgical revision following surgery for ASD were observed; the mean age was 68.9 years (SD 8.7) and 66.9 years (SD 6.6), respectively. On implementing a random forest model, the classification of URO events resulted in a balanced accuracy of 86.8%. Among machine learning-extracted risk factors, URO, proximal junction failure (PJF), and postoperative distance from the posterosuperior corner of C7 and the vertical axis from the centroid of C2 (SVA) were significant upon Kaplan-Meier survival analysis. Conclusion. The major risk factors for URO following surgery for ASD, i.e. postoperative SVA and PJF, and their interactions were identified using a machine learning algorithm and game theory. Clinical benefits will depend on patient risk profiles. Cite this article: Bone Joint Res 2023;12(4):245–255

To examine the impact of a structured rehabilitation programme as part of an integrated multidisciplinary treatment algorithm for adult spinal deformity patients. A prospective cohort study was performed over a 2-year period at a major tertiary referral centre for adult spinal deformity surgery. All consecutive patients requiring 2-stage corrective surgery for sagittal malalignment were included (n=32). Details of physiotherapy initial evaluation, inpatient rehabilitation progress, details of bracing treatment and time to discharge were collected. Clinical outcome scores were measured preoperatively and at 6 weeks, 6 months and 1 year postoperatively. After second stage corrective surgery, the mean time to standing without assistance was 2.1 days, mean time to independent ambulation was 4.2 days, mean time to competent ascending and descending stairs was 5.6 days and mean time to moulded orthosis application 7.1 days. Successful progression through the structured rehabilitation programme was associated with high clinical outcome scores and improved health related quality of life (HRQOL). The introduction of this programme contributed to the development of an enhanced recovery pathway for patients having adult spinal deformity surgery, reducing inpatient length of stay and optimising clinical outcomes

Aim:. To simplify sagittal plane spinal assessment by describing a single novel angle in the lumbar spine equivalent to the difference between pelvic incidence (PI) and lumbar lordosis (LL) and evaluate its reliability. Methods:. New sagittal modifiers in the classification of adult degenerative spinal deformity have been shown to be valid and reliable with the greatest variability being for pelvic incidence minus lumbar lordosis (PI-LL). This measurement can be simplified to a new angle (alpha) without the need to determine either PI or LL. This angle is between a line intersecting the bicoxofemoral centre and perpendicular to the L1 endplate (alpha line) and a line from the bicoxofemoral centre to the centre of the sacral endplate. Two readers graded 40 non-premarked cases twice each, approximately 1 week apart. Inter- and intra-rater variability and agreement were determined for PI-LL and alpha angle separately. Fleiss' kappa was used for reliability measures. Results:. Inter-rater kappa for PI-LL showed substantial reliability and alpha angle showed almost perfect agreement. Intra-rater kappa showed substantial reliability for PI-LL but almost perfect agreement for alpha angle across both readers. Discussion:. Alpha angle can be used as a surrogate for PI-LL and is easier and more reliable to measure. When PI=LL, alpha angle is 0, so the alpha line bisects the sacral plate. Conflict Of Interest Statement: No conflict of interest

To evaluate the differences between spinopelvic parameters before and after sagittal malalignment correction and to assess the relationship between these radiologic parameters and clinical outcome scores.

A prospective cohort study was performed over a 2-year period at a major tertiary referral centre for adult spinal deformity surgery. All consecutive patients requiring 2-stage corrective surgery were included (n=32). Radiographic parameters and clinical outcome measures were collected preoperatively and at 6 weeks, 6 months, 1 year and 2 years postoperatively. Radiographic parameters analysed included pelvic incidence, pelvic tilt, sacral slope, lumbar lordosis, thoracic kyphosis and sagittal vertical axis. Clinical outcome measures collected included EQ-5D, ODI, SRS 22 and VAS Pain Scores.

Correction of sagittal malalignment was associated with significant improvements in HRQOL. Restoration of lumbar lordosis, pelvic tilt and sagittal vertical axis correlated with postoperative improvements in EQ-5D, ODI, SRS 22 and VAS Pain Scores at follow-up.

This study demonstrates that the magnitude of sagittal plane correction correlates with the degree of clinical improvements in HRQOL. This further underlines the need for spinal surgeons to target complete sagittal plane deformity correction if they wish to achieve the highest rates of HRQOL benefit in patients with marked sagittal malalignment.

To evaluate the incidence of complications and the radiographic and clinical outcomes from 2-stage reconstruction including 3-column osteotomy for revision adult spinal deformity. A prospective cohort study performed over 2 years at a major tertiary referral centre for adult spinal deformity surgery. All consecutive patients requiring 2-stage corrective surgery for revision adult spinal deformity were included. Radiographic parameters and clinical outcome measures were collected preoperatively and at 6 weeks, 6 months, 1 year and 2 years postoperatively. Radiographic parameters analysed included pelvic incidence, pelvic tilt, sacral slope, lumbar lordosis, thoracic kyphosis and sagittal vertical axis. Clinical outcome measures collected included EQ-5D, ODI, SRS 22 and VAS Pain Scores. Performing anterior column reconstruction followed by 3-column osteotomy and extension of instrumentation for revision spinal deformity resulted an excellent correction of sagittal alignment, minimal surgical complications and significant improvements in HRQOL. Restoration of lumbar lordosis, pelvic tilt and sagittal vertical axis were observed in addition to postoperative improvements in EQ-5D, ODI, SRS 22 and VAS Pain Scores at follow-up. Performing anterior column reconstruction prior to a 3-column osteotomy minimises complications associated with 3-column osteotomy and extension of posterior instrumentation. We propose a treatment algorithm for safe and effective treatment in revision adult deformity surgery

Currently, between 17% of patients undergoing surgery for adult spinal deformity experience severe instrumentation related problems such as screw pullout or proximal junctional failure necessitating revision surgery. Cables may be used to reinforce pedicle screw fixation as an additive measure or may provide less rigid fixation at the construct end levels in order to prevent junctional level problems. The purpose of this study is to provide insight into the maximum expected load during flexion in UHMWPE cable in constructs intended for correction of adult spine deformity (degenerative scoliosis) in the PoSTuRe first-in-man clinical trial. Following the concept of toppinoff, a new construct is proposed with screw/cable fixation of rods at the lower levels and standalone UHMWPE cables at the upper level (T11). A parametric FE model of the instrumented thoracolumbar spine, which has been previously validated, was used to represent the construct. Pedicle screws are modeled by assigning a rigid tie constraint between the rod and the lamina of the corresponding spinal level. Cables are modeled using linear elastic line elements, fixing the rod to the lamina medially at the cranial laminar end and laterally at the caudal laminar end. A Youngs modulus was assigned such that the stiffness of the line element was the same as that of the cable. An 8 Nm flexion moment was applied to the cranial endplate. The maximum value of the force in the wire (80 N) is found at the T11 (upper) level. At the other levels, forces in the cable are very small because most of the force is carried by the screw (T12) or because the wires are force shielded by the contralateral and adjacent level pedicle screws (L2, L3). The model provides first estimates of the forces that can be expected in the UHMWPE cables in constructs for kyphosis correction during movement. It is expected that this approach can help in defining the number of wires for optimal treatment

Modern techniques facilitate the treatment of adult spinal deformity. Decision making is a challenge because of potential complications relating to the surgery itself and medical problems. This study aims to provide useful data in facilitating the decision making process. Retrospective analysis of consecutive single surgeon series of patients aged >50 between 2006-2009 undergoing multi-level spinal deformity surgery with concomitant decompression. Medical co-morbidities, age and ASA were recorded. 71 patients (57 female) mean age 66 (50-83). 29 (12 multiple) failed previous stenosis surgery. 14(19.7%) in hospital complications in 11(15.5%) patients. 4 were ‘medical’. 8/11 patients were revision cases versus 3/11 primary. 4 patients (5.6%) needed further surgery. 13(18.3%) outpatient complications in 12(16.9%)patients. 7/12 occurred in revision cases versus 5/12 in primary. 11(15.5%) needed further surgery. Revisional surgery in adult deformity presents a significantly higher overall complication rate than primary surgery (p= 0.0084), but both revisional and primary cases have a relatively high re-operation rate once initially discharged. The results indicate that complex medical and surgical factors contribute to the decision making challenge in patients with adult spinal deformity and stenosis

INTRODUCTION. Standing spinal alignment has been the center of focus recently, particularly in the setting of adult spinal deformity. Humans spend approximately half of their waking life in a seated position. While lumbopelvic sagittal alignment has been shown to adapt from standing to sitting posture, segmental vertebral alignment of the entire spine is not yet fully understood, nor are the effects of DEGEN or DEFORMITY. Segmental spinal alignment between sitting and standing, and the effects of degeneration and deformity were analyzed. METHODS. Segmental spinal alignment and lumbopelvic alignment (pelvic tilt (PT), pelvic incidence (PI), lumbar lordosis (LL), PI-LL, sacral slope) were analyzed. Lumbar spines were classified as NORMAL, DEGEN (at least one level of disc height loss >50%, facet arthropathy, or spondylolisthesis), or DEFORMITY (PI-LL mismatch>10°). Exclusion criteria included lumbar fusion/ankylosis, hip arthroplasty, and transitional lumbosacral anatomy. Independent samples t-tests analyzed lumbopelvic and segmental alignment between sitting and standing within groups. ANOVA assessed these differences between spine pathology groups. RESULTS. There were 183 NORMAL, 216 DEGEN and 92 DEFORMITY patients with significant differences in age, gender, and hip OA grades. After propensity matching for these factors, there were 56 patients in each group (age 63±14, 58% female) [Fig. 1]. Significant differences were noted between spinal pathology groups with regard to changes from standing to sitting alignment with regard to NORMAL vs DEGEN vs DEFORMITY groups in PT (13.93° vs −11.98° vs − 7.95°; p=0.024), LL (21.91° vs 17.45° vs 13.23°; p=0.002), PI-LL (−22.32° vs −17.28° vs −13.18°; p<0.001), SVA (−48.99° vs −29.98° vs −32.12°; p=0.002), and TPA(−16.35° vs −12.69° vs −9.64; p=0.001). TK (−2.08° vs −2.78° vs −2.00°, p=0.943) and CL (−3.84° vs −4.14° vs −3.57°, p=0.621) were not significantly different across spinal pathology groups [Fig. 2]. NORMAL patients had overall greater mobility in the lower lumbar spine from standing to sitting compared to DEGEN and DEFORMITY patients. L4-L5 (7.50° vs 5.23° vs 4.74°, p=0.012) and L5-S1 (6.96° vs 5.28° and 3.69°, p=0.027). There were no significant differences in change in alignment from standing to sitting at the upper lumbar levels or lower thoracic levels between the three groups [Fig. 3]. CONCLUSION. The lower lumbar spine provides the greatest sitting to standing change in lumbopelvic alignment in normal patients. Degeneration and deformity of the spine significantly reduces the mobility of the lower lumbar spine and PT. With lumbar spine degeneration and flatback deformity, relatively more alignment change occurs at the upper lumbar spine and thoracolumbar junction

Aim:. An analysis of significant neuromonitoring changes (NMCs) and evaluation of the efficacy of multimodality neuromonitoring in spinal deformity surgery. Method:. A retrospective review of prospectively collected data in 320 consecutive paediatric and adult spinal deformity operations. Patients were sub-grouped according to demographics (age, gender), diagnosis, radiographic findings (Cobb angles, MR abnormalities) and operative features (surgical approach, duration, levels of fixation). Post-operative neurological deficit was documented and defined as either spinal cord or nerve root deficit. Results:. 296 paediatric and adult patients were monitored in 320 consecutive spinal deformity operations between 2003 and 2013. Combined monitoring with SSEPs and MEPs was considered successful (296 of 320 operations), when it was able to produce reproducible signals with regards to SEP and / or MEP. SEP was attempted but unrecordable in 1 case, while MEPs were contraindicated in 23 cases due to epilepsy and/or medications. The overall incidence of significant NMC was 7.5% (24 NMCs out of 320 operating episodes) and overall neurological deficit was 1.6%. There were 19 true positives, 5 false positives and zero false negative results. When results were collated, the overall combined sensitivity of multimodal monitoring was 100%, specificity 98.3%, PPV 79.2% and NPV 98.3%. Discussion:. Multimodal monitoring allows accurate assessment and prevention of permanent neurological deficit that is superior to any single monitoring modality. Conflict Of Interest Statement: No conflict of interest

Précis: A recently developed Classification of adult scoliosis was utilised to study surgical treatment in 339 patients. At 12 month follow up after surgery for thoracolumbar/lumbar scoliosis greatest improvement in outcome scores were noted in the following patients: lost lumbar lordosis, treatment with osteotomies, fusion to the sacrum for marked sagittal imbalance. Complication rates were greatest for: fusion to the sacrum, sagittal imbalance greater than 4cm. Introduction: A recently proposed radiographic Classification of adult scoliosis offers a useful system with high clinical impact and reliability. Continued work is required to apply this system in the development of treatment guidelines. The purpose of this study was to anal surgical treatment outcomes, and complications, by Classification subtype at 12 months post-operative follow up. Material and Method: This study included 339 patients: Type IV (thoracolumbar major) and Type V (lumbar major) adult scoliosis (Spinal Deformity Study Group). All patients had complete full-length spine radiographs and outcomes questionnaires (SRS, ODI and SF-12). An analysis of classification subtypes (modifiers) included outcome scores by surgical treatment. The latter included approach (anterior, posterior, both), use of osteotomies, and extension to the sacrum (or not). Results: Lordosis modifier was strongly correlated with baseline disability and post-operative improvement. Type C (loss of lordosis) patients had the lowest baseline outcome but also greatest improvement with surgery (p< 0.05). Subluxation modifier had impact on preoperative but not on postoperative outcomes measures. Marked sagittal balance had the worst outcomes of all groups if fusion fell short of the sacrum. Patients with osteotomies saw greater improvement than those without (p< 0.05). Anterior, posterior or combined procedures showed no significant difference in outcomes. Peri- and post-operative complications did not vary by lordosis modifier, subluxation modifier but were elevated for fusion to the sacrum (p< 0.05). Conclusion: At 12 month follow up for surgical treatment of adult thoracolumbar/lumbar scoliosis greatest improvement in outcome scores were noted in the following patients: lost lumbar lordosis, treatment with osteotomies, fusion to the sacrum for marked sagittal imbalance. Complication rates were greatest for: fusion to the sacrum, sagittal imbalance greater than 4cm. Further longitudinal follow up will permit validation of optimal treatment by Classification type of adult spinal deformity and refine patient and surgeon expectations of operative care

Précis: A multi-centre prospective effort focused on analysis of a previously reported Classification of adult scoliosis. 809 thoracolumbar/lumbar deformities were studied. Radiographic analysis (deformity apex, lumbar lordosis, intervertebral subluxation), outcomes measures (ODI, SRS instruments) and surgical rates were examined. The Classification into Types, based on deformity apex location, and addition of modifiers (lordosis, subluxation) established clinically significant groups (disability, pain). In addition to high clinical impact, the Classification was also able to predict surgical rates. Introduction: A recently proposed radiographic classification of adult scoliosis offers a reliable method of categorizing patients. Continued work on this classification is expected to develop treatment guidelines. This investigation anald treatment patterns of a large patient population of thoracolumbar and lumbar adult scoliosis, emphasizing surgical rates and approaches by classification subtypes. Methods: This investigation anald 809 Type IV (thoracolumbar major) and Type V (lumbar major) curves from the Spinal Deformity Study Group database. Enrolled patients had complete SRS, ODI and SF-12 outcomes questionnaires and free standing full-length spine radiographs. Analysis compared non-operative versus surgical treatment (no imposed protocol) with surgical treatment assessed by approach (anterior, posterior, both), +/− osteotomies. Results: Of 809 patients, 348 were treated surgically (43%) and classified as lordosis type A (n=422), B (n=313), C (n=74). Surgical rates were greater for B vs. A (51% vs. 37%, p< 0.05)), trend for A vs. C (46%). Subluxation modifier scores: 0 (n=360), + (n=159), ++ (n=290). Surgical rates were greater for ++ vs. 0 (52% vs. 36 %, p< 0.05), trend vs. + (42 %). Greater sagittal imbalance was more likely to receive surgical treatment. Loss of lumbar lordosis (modifier B, C) was associated with increased osteotomy rates and posterior or circumferential treatment versus anterior only procedures (most common in modifier A). Greater subluxation (modifier ++) was associated with more circumferential surgery. Greater sagittal imbalance was associated with higher rate of posterior only surgery. Discussion: In this analysis, greater lordosis or subluxation modifier score was associated with higher surgical rates. Loss of lordosis and greater subluxation grade was associated with higher rates of circumferential surgery than lordotic spines or those without significant subluxation. This information suggests the ability of this classification system to predict treatment. Longitudinal follow up will permit validation of optimal treatment by classification of adult spinal deformity

During the last 2 decades it has been recognized that scoliosis may start de novo during adult life as a result of advanced degenerative disc disease, osteoporosis or both. In some the degenerative process is superimposed on a previous adolescent curve. Aside from the disfigurement caused by the spinal deformity, pain and disability are usually the major clinical problem. The prevalence of adult scoliosis rises with age: from 4% before age 45, 6% at age 59 to 15% in-patients older than 60 years. More than two thirds of the patients are females and the prevalence of right lumber curves is higher than in comparable series of patients with adolescent scoliosis. Adult scoliosis is characterized by vertebral structural changes with translatory shifts i.e. lateral olisthesis accompanied by degenerative disc and facet joint arthrosis. Although the magnitude of these curves is usually mild (20–30 degrees) lateral spondylolisthesis is observed frequently. It is also common to observe degenerative spondylolisthesis in patients with degenerative lumbar scoliosis. The annual rate of curve progression ranges from 0.3 to 3%. Patients present with a history of a spinal deformity accompanied by loss of lumbar lordosis, trunk imbalance and significant mechanical back pain. Pain may arise not only from degenerative disc disease and facet arthritis leading to symptoms of spinal stenosis, but also from muscle fatigue due to the altered biomechanics secondary to a deformity in the coronal and sagittal planes. Root entrapment is common and occurs more often on the concavity of the curve. Symptoms of neurogenic claudication are also common in adults with lumbar scoliosis. Non-operative care includes exercises, swimming, NSAIDs, and occasional epidural injections. Brace treatment can be tried as well. Curve progression as well as axial or radicular pain not responding to non-operative care are indications for surgical intervention. Surgery may include decompression alone or in conjunction with curve correction and stabilization. Posterior instrumentation may be supplemented with interbody cages. Fusion is usually carried down to L5 but occasional instrumentation to the sacropelvis is mandatory. Problems with a high pseudoarthrosis rate are common with sacral fixation. Even in the best of hands a long recovery period (6–12 month) and moderate pain relief should be expected. As summarized by Dr. Bradford “despite recent advancements evaluation and successful management of patients with adult spinal deformity remains a significant challenge”

Aims

Symptomatic spinal stenosis is a very common problem, and decompression surgery has been shown to be superior to nonoperative treatment in selected patient groups. However, performing an instrumented fusion in addition to decompression may avoid revision and improve outcomes. The aim of the SpInOuT feasibility study was to establish whether a definitive randomized controlled trial (RCT) that accounted for the spectrum of pathology contributing to spinal stenosis, including pelvic incidence-lumbar lordosis (PI-LL) mismatch and mobile spondylolisthesis, could be conducted.

Aims

With resumption of elective spine surgery services in the UK following the first wave of the COVID-19 pandemic, we conducted a multicentre British Association of Spine Surgeons (BASS) collaborative study to examine the complications and deaths due to COVID-19 at the recovery phase of the pandemic. The aim was to analyze the safety of elective spinal surgery during the pandemic.

Aims

Severe spinal deformity in growing patients often requires surgical management. We describe the incidence of spinal deformity surgery in a National Health Service.