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Background: Intraoperative neuromonitoring (IONM) alert is one of the worrying events of kyphosis corrective surgery, which can result in a postoperative neurological deficit. To our knowledge, there is no risk prediction score to predict such events in patients undergoing kyphosis surgery., Purpose: To develop a new preoperative MRI-based cord morphology classification (CMC) and risk prediction score for predicting IONM alerts in patients with kyphotic deformity., Study Design: Retrospective analysis of prospectively collected data., Patient Sample: About 114 patients undergoing surgical correction for kyphotic deformity., Outcome Measures: Intraoperative neuromonitoring alerts and postoperative neurological status using AIS grading., Methods: Kyphotic deformity patients undergoing posterior spinal fusion were retrospectively reviewed. Based on the morphology of the spinal cord and surrounding CSF in MRI, there are 5 types of cord. Type 1 (normal cord): circular cord with surrounding visible CSF between the cord and the apex, Type 2 (flattened cord): cord with <50% distortion at the apex with obliteration of the anterior CSF; Type 3 (deformed cord): cord with >50% distortion at the apex with complete obliteration of the surrounding CSF; Type 4 (stretched cord): the cord is stretched and atrophied over the apex of the curve. Type 5 (translated cord): horizontal translation of the cord at the apex with buckling collapse of the vertebral column. Preoperative radiographs were used to measure the preoperative sagittal cobbs angle, sagittal deformity angular ratio (S-DAR), sagittal vertical axis (SVA), apex of the curve, and type of kyphosis. Clinical data like the duration of symptoms, clinical signs of myelopathy, neurological status (AIS grade), grade of myelopathy using the mJOA score, and type of osteotomy were documented. Multivariate logistic regression was used to determine the risk factors for IONM alerts and the risk prediction score was developed which was validated with new cohort of 30 patients., Results: A total of 114 patients met the inclusion criteria. IONM alerts were documented in 33 patients (28.9%), with full recovery of the signal in 25 patients and a postoperative deficit in 8 patients. Rate of IONM alerts was significantly higher in Type 5 (66%), followed by Type 4 (50%), Type 3 (21.1%), Type 2 (11.1%), and Type 1 (11.1%) (p-value<.001). Based on multiple logistic regression, 7 factors, namely preoperative neurological status, mJOA score≤6, presence of signs of myelopathy, apex of the curve above T5, preoperative sagittal cobbs, S-DAR, and MRI-based CMC, were identified as risk predictors. The value for the risk factors varies from 0 to 4, and the maximum total risk score was 13. The cut-off value of 6 had good sensitivity (84.9%) and specificity (77.8%) indicating a high risk for IONM alerts. The AUC of the predictive model was 0.92, indicating excellent discriminative ability., Conclusion: We developed and validated a risk predictive score that identifies patients at risk of IONM alerts during kyphosis surgery. Identification of such high-risk patients (risk score≥6) helps in proper evaluation and preoperative counselling and helps in providing a proper evidence-based reference for treatment strategies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Pulmonary dysfunction in thoracic kyphoscoliosis has been correlated with chest wall distortion, uneven trunk growth and restrictive pattern. The study aims to analyse the variation in thoracic inlet measurements on pulmonary dysfunction with varying curve magnitude and thoracic cage parameters., Methods: In a non-randomised, prospective case-control study, 80 consecutive patients with thoracic kyphoscoliosis were divided into 3 groups based on Cobb angle: Group 1 (31-50), Group 2 (51-80) and Group 3 (> 80). Thoracic inlet measurement was calculated by thoracic inlet index (TI) on MRI at the sternal level. Pulmonary function and thoracic cage parameters [hemi thorax height, rib-apex distance, AP chest diameter at sternal level and transverse thoracic diameter] were documented. TI values were compared with 20 age-matched asymptomatic controls. Multivariate correlation and regression analysis were performed to investigate the correlations., Results: The mean age of the study cohort was 14.1 ± 4.4 years, including Group 1 (6 patients), Group 2 (55 patients) and Group 3 (19 patients) versus 12.9 ± 2.2 years in controls. The mean TI was 2.8 ± 0.56 in Group 1, 3.7 ± 0.9 in Group 2 and 4.0 ± 1.12 in Group 3 versus 2.6 ± 0.43 in controls. Pulmonary dysfunction was severe with TI > 7.1 (p < 0.001) in Group 3 patients with thoracic hypokyphosis. Multivariate regression for thoracic parameters and TI > 5.6 showed significant correlation of pulmonary dysfunction in Group 2 and 3 curves with apex between T1 and T4, whereas transverse thoracic diameter, rib-apex distance and hemi thorax height were weakly associated., Conclusion: Thoracic inlet index (TI), a neglected pre-operative variable associated with pulmonary dysfunction in thoracic kyphoscoliosis, can be evaluated on MRI without an additional cost and radiation., (© 2024. The Author(s), under exclusive licence to Scoliosis Research Society.)

Purpose: To discuss the effect of posterior instrumented deformity correction and fusion on the progressive endochondral ossification of anterior vertebral body in a patient with congenital kyphosis secondary to type 1 vertebral anomaly., Methods: A 15-year-old male patient presented with a progressively worsening congenital TL kyphosis of 52° magnitude secondary to a posterior hemivertebra. His pre-operative antero-posterior vertebral height ratio (APVHR) and anterior vertebral body defect ratio (AVBDR) on CT were 38% and 49%, respectively. He underwent posterior instrumented deformity correction with multilevel type 1 Schwab osteotomies and fusion., Results: Over the next 3 years, his serial imaging revealed progressive endochondral ossification and gradual increase in the dimensions of the vertebral body. At the final follow-up, there was a significant restoration of the deficient anterior vertebral body, and the final APVHR and AVBDR were 81% and 90%, respectively., Conclusions: Restitution of posterior column integrity through stabilization can mitigate the compressive stresses across anterior column. Over a period of time, forces restraining the growth of anterior vertebral apophysis are alleviated, and the vertebra can potentially re-grow to near-normal dimensions in pediatric population. This phenomenon could be well-demonstrated in our patient during follow-up., Level of Evidence I: Diagnostic: individual cross-sectional studies with the consistently applied reference standard and blinding., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objective: To report on the phenomenon of body drift in neurofibromatosis scoliosis and discuss its implication on surgical safety., Materials and Methods: Ten dystrophic neurofibromatosis scoliosis (NF) and ten adolescent idiopathic scoliosis (AIS) were studied by radiographs, CT, and MRI. The curve characteristics and a detailed analysis of the morphology of the apical and three adjacent vertebral segments above and below were done. The coronal alignment and the presence of a drift of the vertebral body in relationship to the lamina were carefully studied in both groups and compared., Results: The mean cobb angle in the NF group was 77.6°, and 63.7° in the AIS group. All the studied vertebra in the NF group had extensive pedicle changes, which were more severe at the apical and periapical regions. Body drift was noted in 29 vertebral segments, with 9/10 of apical segments showing a significant drift. The body drift was associated with significant pedicle dystrophic changes and was independent of the curve magnitude. In comparison, in AIS, no body drift was noted despite a larger deformity and more severe vertebral rotation., Conclusion: The 'body drift' phenomenon was unique to neurofibromatosis scoliosis and was secondary to severe pedicle morphology changes. This was present even in curves less than 60° and could result in cord injury while instrumenting the concave pedicle. Therefore, a thorough preoperative assessment and planning by a 3D CT are mandatory., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: Congenital spinal deformities (CSD) are uncommon; and usually present during early childhood. Rarely, patients have been reported to present with neglected CSD in association with myelopathy. The current study reports the largest series of patients with neglected CSD and major neuro-deficit; and discusses their long-term outcome., Methods: We retrospectively analysed patients with CSD who presented with myelopathy and underwent surgical management between January 2008 and January 2018. Only patients who had complete clinico-radiological records and completed minimum 2-year follow-up were included. Neurology was graded according to American Spinal Injury Association Impairment, Nurick and modified Japanese Orthopaedic Association scores. Radiological details like deformity type, location, magnitude, and underlying anomaly were recorded. A comparative analysis of parameters between pre-operative and final follow-up periods was performed., Results: Thirty three (age = 21.1 ± 11.9 years) patients with CSD and myelopathy were included. Mean duration since myelopathy was 5.2 ± 6.2 months. Thirty (91%) patients presented with kyphosis or kyphoscoliosis; and 18 had upper thoracic-level lesion (12 and 3 with mid- or low-thoracic and lumbar lesions). 16 (48.5%) and 12 (36.4%) presented with types 1 and 3 anomalies, respectively. Mean pre-operative mJOA and Nurick grades were 8.8 ± 2.4 and 3.4 ± 0.7. Based on ASIA score, 2, 5, 21 and five patients presented with grades A, C, D and E, respectively. All patients underwent surgeries from posterior-only approach. Mean follow-up was 4.7 ± 2.6 years. In kyphoscoliosis group, coronal and sagittal Cobb improved by 23.8° and 25.9°, respectively. Mean deformity improved by 19.6° and 15.6° in scoliosis and kyphosis groups, respectively. Neurological status improved in 5, remained stable in 23 and deteriorated in five patients. Mean mJOA and Nurick grades at final follow-up was 8.3 ± 3.1and 3.4 ± 0.9., Conclusion: Major neurological deficit is a rare complication of neglected CSD. In our series, such a presentation was observed in patients with kyphotic or kyphoscoliotic deformities, type 1 or 3 vertebral anomalies and proximal thoracic vertebral lesions. Surgery can be valuable in these patients, as it not only stabilises deformity, but also provides the best chance of preventing neuro-deterioration., (© 2021. Scoliosis Research Society.)

Purpose: To document baseline cervical sagittal characteristics in Lenke 1 adolescent idiopathic scoliosis (AIS) patients and assess the alteration in these parameters with surgery., Methods: Pre-operative and 2-year postoperative radiographs of 82 Lenke 1 AIS patients recruited from five hospitals were analysed. Selected radiographic parameters capturing regional and global sagittal alignment were measured. Comparison was made between groups based on baseline thoracic kyphosis (TK: TK < 20°, TK ≥ 20°). Pre-operative and postoperative values were compared-the change in each radiographic parameter was correlated with the degree of sagittal and coronal correction., Results: At baseline, TK was 29.8° ± 16°, cervical lordosis (CL) was - 1° ± 14°, lumbar lordosis (LL) was - 57.1° ± 21°, C2-C7 sagittal vertical axis (SVA) was 16 ± 14 mm and C7-S1 SVA was - 15 ± 28 mm; 44% of patients had cervical kyphosis. Patients with thoracic hypokyphosis had a significantly lower LL and more kyphotic cervical spine compared to those with thoracic normohyperkyphosis. The effect of surgery on TK depended on pre-operative thoracic sagittal alignment-TK increased in patients with thoracic hypokyphosis, but decreased in patients with thoracic normohyperkyphosis. Neither CL nor C2-C7 SVA changed significantly with surgery; 46% of patients still had cervical kyphosis postoperatively., Conclusion: There is a high incidence of cervical kyphosis at baseline in AIS patients-more so in those with pre-operative thoracic hypokyphosis. Unlike TK, CL is not significantly altered with surgery-improvement in CL correlates weakly with sagittal correction of the structural curve., (© 2021. Scoliosis Research Society.)

Purpose: A 17-year-old adolescent with neurofibromatosis and severe cervicothoracic deformity was identified to have thoracic inlet compression leading to bradycardia and hypotension, only during prone positioning, and we discuss its successful management., Methods: Preoperative halo-gravity traction reduced the deformity from 126° to 91°. During prone positioning, sudden onset bradycardia was followed by asystole, which disappeared immediately on turning over to supine position. Surgery was called off after two additional failed attempts of prone positioning., Results: A retrospective analysis of CT and MRI showed severe narrowing of the thoracic inlet. In this patient, the right thoracic inlet was severely narrow, and prone positioning caused a further dynamic compromise stimulating right vagal nerve. The right vagus supplies the sinoatrial node, which is the natural pacemaker of the heart, and its stimulation causes sympathetic inhibition. Bezold-Jarisch reflex is a cardio-inhibitory reflex occurring due to vagal stimulation resulting in sudden bradycardia, asystole, and hypotension. To facilitate prone positioning, the medial end of the clavicles, along with limited manubrium excision, was performed relieving the vagal compression. C2-T4 instrumented decompression followed by anterior reconstruction and cervical plating was performed. The postoperative period was uneventful, and the final deformity was 45°., Conclusion: Bezold-Jarisch Reflex as a result of narrow thoracic inlet caused by cervical kyphosis and compensatory hyperlordosis of the upper thoracic spine has never been reported. This case highlights the need to introspect into thoracic inlet morphology in severe cervicothoracic deformities. Thoracic inlet decompression is an efficient way of addressing this unique complication.

Study Design: Case report OBJECTIVE: To present three cases of coronal vertebral dislocation due to congenital multiple thoracic and lumbar pedicle agenesis., Summary of Background Data: Congenital pedicle agenesis is an uncommon condition and is frequently identified as an incidental finding on diagnostic imaging in asymptomatic individuals. This agenesis is frequently limited to a single level and is commonly seen in the cervical and lumbar spine., Methods: We report three patients who presented with multiple thoracic and lumbar pedicle agenesis resulting in coronal vertebral dislocation. The patients presented with progressive kyphoscoliosis deformity. Identification of this malformation on conventional radiographs is difficult, and computed tomographic (CT) scan with 3D reconstruction provides a better delineation of the deformity., Results: Computed tomography showed complete absence of pedicles and dissociation of anterior column from the posterior column, resulting in coronal vertebral dislocation. Magnetic resonance imaging confirmed the absence of pedicles and decreased anteroposterior diameter, causing canal stenosis. Two patients were treated by spanning internal fixation, partial deformity correction, and posterior fusion, with satisfactory results., Conclusion: Coronal vertebral dislocation can be easily missed on plain radiograph because many patients with severe scoliotic deformity have thin or sclerotic pedicles. Computed tomography is essential to demonstrate these anomalies. It is important to recognize pedicle aplasia early to prevent rapid progression of deformity and neurologic deficit., (Copyright © 2018 Scoliosis Research Society. Published by Elsevier Inc. All rights reserved.)

Background: There is a lack of a classification system providing uniformity in description and guiding management decisions for kyphotic spinal deformities. We developed such a classification based on column deficiency, flexibility of disc spaces, curve magnitude, and correlation with the corrective osteotomy required., Methods: A classification was developed based on analysis of 180 patients with thoracolumbar kyphosis requiring osteotomy. The deformity was classified as Type I if the anterior and posterior columns were intact (IA indicated mobile disc spaces and IB, ankylosed segments). Type II indicated deficiency of only 1 column (IIA = anterior column and IIB = posterior column). Type III indicated deficiency of both columns (IIIA = kyphosis of ≤60°, IIIB = kyphosis of >60°, and IIIC = buckling collapse). A prospective analysis of 76 patients was performed to determine interobserver variability and the ability of the classification to guide selection of osteotomies of increasing complexity, including the Ponte osteotomy, pedicle subtraction osteotomy, disc bone osteotomy, single vertebrectomy, multiple vertebrectomies, and anterior in situ strut fusion procedure., Results: The mean age of the 76 patients was 21.2 years, the mean kyphosis was 69.9° (range, 26° to 120°), and the mean follow-up duration was 30 months. Six deformities were classified as IA, 5 as IB, 5 as IIA, 2 as IIB, 13 as IIIA, 35 as IIIB, and 10 as IIIC. Four surgeons classifying the deformities had a high agreement rate (kappa = 0.83), with the highest agreement for Types IA, IB, and IIIB. A correlation between the type of deformity and the osteotomy performed demonstrated that the classification could indicate the type of osteotomy required. All 18 patients with Type-I or II kyphosis were treated with Ponte, pedicle subtraction, or disc bone osteotomy. Forty-three (90%) of the 48 patients with Type IIIA or IIIB underwent vertebrectomy (single in 27 [56%] and multiple in 16 [33%]), and only 5 (10%) underwent disc bone osteotomy. Seven of the 10 patients with Type-IIIC kyphosis were treated with multiple vertebrectomies, with 5 of them needing preoperative halo gravity traction; the other 3 patients underwent an anterior in situ strut fusion procedure., Conclusions: The proposed classification based on the morphology of column deficiency, flexibility, and curve magnitude demonstrated a high interobserver agreement and ability to guide selection of the appropriate osteotomy., Clinical Relevance: A novel classification system for kyphosis based on spinal column deficiency, flexibility of disc spaces, and curve magnitude would bring uniformity in management and help guide surgeons in the choice of the appropriate corrective osteotomy.

Study Design: Vertebral defects were created in a validated 3D finite element model (FEM) to simulate destructive tubercular lesions of increasing severity. Forces in various parts of the spine were then calculated and correlated to deformity progression and growth modulation (GM) changes., Objective: To understand the biomechanical basis of GM, which governs spinal growth and the progression of kyphosis in posttubercular kyphotic (PTK) deformities., Summary of Background Data: Hueter-Volkmann Law (HVL), chondral growth force response curve (CGFRC), and regional growth acceleratory phenomenon have all been proposed to explain the modulation of growth in limbs but have not been tested in vertebral end plates (VEP). We have previously documented various GM changes in posttubercular kyphotic. By simulating the kyphotic collapse in a validated FEM, the mechanical basis of GM can be established., Methods: Sixty-three children with tuberculosis treated conservatively formed the clinical material. The progress of deformity and GM changes in the fusion mass and the kyphotic curve was documented. Defects simulating lesions of four levels of severity (types A, B, C, and D) were created in a validated 3D FEM and subjected to load till restabilization occurred. The stresses at the end plates, discs, facet joints, and the points of contact were calculated., Results: Regional growth acceleratory phenomenon and favorable growth changes were found in type A collapse where the facets were intact. With increasing destruction, the forces in the facet capsules increased beyond 30 MPa predicting facet dislocations in types B, C, and D collapse. As the contact stress on the VEP increased to 16.6 MPa (type B) and 40 MPa (type C), this was associated with growth suppression. Type D collapse involved facet dislocation at multiple levels leading to "buckling collapse". Acceleratory growth was found both in tension and compression phases proving that VEP growth followed principles of CGFRC rather than HVL., Conclusion: This is the first study in the current literature to demonstrate that spinal growth follows CGFRC rather than HVL. This observation opens a potential window of opportunity to treat spinal deformities by mechanical GM.

Childhood spinal tuberculosis, especially when associated with severe vertebral destruction of more than two vertebral bodies can end up in severe deformity. These children show progressive deformity throughout the period of growth and can develop severe kyphosis of >100°. Such kyphosis is severely disabling with significant risk of neurological deficit and respiratory compromise. Surgical correction of these deformities by both anterior and posterior approaches has been described but each have serious limitations of approach, correctability and safety. We describe here a technique of posterior closing-anterior opening osteotomy, which allowed us to correct a rigid post-tubercular deformity of 118° in a 13-year-old boy with neglected spinal tuberculosis. The patient was a 13-year-old boy, who had contracted spinal tuberculosis at the age of 6 years. Although the disease was cured by anti-tubercular chemotherapy, he continued to deteriorate in deformity and presented to us with severe thoracolumbar kyphosis (118°). He was neurologically intact but was beginning to show shortness of breath on exertion. Patient also had fore shortening of the trunk with impingement of the rib cage on the iliac crest. Radiographs revealed complete destruction of T12, L1 and L2 vertebral bodies with the T11 vertebra fusing with L3 anteriorly. CT scans and MRI revealed severe collapse of the vertebral column and the spinal cord being stretched over the 'internal gibbus', which was formed by the remnants of the destroyed vertebrae. A single stage closing-opening osteotomy was done by a midline posterior approach with continuous intraoperative spinal cord monitoring. The procedure involved extensive laminectomy of T11-L2, pedicle screw fixation of three levels above and three levels below the apex, a wedge osteotomy at the apex of the deformity from both sides, anterior column reconstruction by appropriate-sized titanium cage and gradual correction of deformity by closing the posterior column using the cage as a fulcrum. This allowed us to achieve a correction to 38° (68% correction). There was no intraoperative or perioperative adverse event and patient had good functional and radiological outcome at 1-year follow-up. In this Grand Rounds case presentation, we have also discussed the aetiology and evolution of severe post-tubercular kyphosis, which is the most common cause of spinal deformity in the developing world. Early identification of children at risk for severe deformity, the time and ideal methods of prevention of such deformities are discussed. The pros and cons of the available options of surgical correction of established deformity and the merits of our surgical technique are discussed.

The correction of severe post-tubercular kyphosis (PTK) is complex and has the disadvantage of being multiple staged with a high morbidity. Here, we describe the procedure and results of closing-opening osteotomy for correction of PTK which shortens the posterior column and opens the anterior column appropriately to correct the deformity without altering the length of the spinal cord. Seventeen patients with PTK (10 males; 7 females) with an average age of 18.3 +/- 10.6 years (range 4-40 years) formed the study group. There were ten thoracolumbar, one lumbar and six thoracic deformities. The number of vertebrae involved ranged from 2 to 5 (average 2.8). Preoperative kyphosis averaged 69.2 degrees +/- 25.1 degrees (range 42 degrees -104 degrees ) which included ten patients with deformity greater than 60 degrees . The average vertebral body loss was 2.01 +/- 0.79 (range 1.1-4.1). The neurological status was normal in 13 patients, Frankel's grade D in three patients and grade C in one. Posterior stabilization with pedicle screw instrumentation was followed by a preoperatively calculated wedge resection. Anterior column reconstruction was performed using rib grafts in four, tricortical iliac bone graft in five, cages in six, and bone chips alone and fibular graft in one patient each. Average operating time was 280 min (200-340 min) with an average blood loss of 820 ml (range 500-1,600 ml). The postoperative kyphosis averaged 32.4 degrees +/- 19.5 degrees (range 8 degrees -62 degrees ). The percentage correction of kyphosis achieved was 56.8 +/- 14.6% (range 32-83%). No patient with normal preoperative neurological status showed deterioration in neurology after surgery. The last follow-up was at an average of 43 +/- 4 months (range 32-64 months). The average loss of correction at the last follow-up was 5.4 degrees (range 3 degrees -9 degrees ). At the last follow-up, the mean preoperative pain visual analogue scale score decreased significantly from 9.2 (range 8-10 points) to 1.5 (range 1-2 points). There was also a significant decrease in mean preoperative Oswestry's Disability Index from 56.4 (range 46-68) to 10.6 (range 6-15). Complications were superficial wound infections in two, neurological deterioration in one, temporary jaundice in one and implant failure requiring revision in one. Single-stage closing-opening wedge osteotomy is an effective method to correct severe PTK. The procedure has the advantage of being a posterior only, single-stage correction, which allows for significant correction with minimal complications.

Study Design: A retrospective cohort study. Purpose: To determine outcomes following all-posterior surgery using computed tomography navigation, hybrid stabilization, and multiple anchor point techniques in patients with neurofibromatosis type 1 (NF-1) and dystrophic scoliosis. Overview of Literature: Previous studies favored antero-posterior fusion as the most reliable method; however, approaching the spine anteriorly was fraught with significant complications. With the advent of computer assisted navigation and multiple anchor point method, posterior only approach is reporting successful outcomes. Methods: This study included patients who underwent all-posterior surgical deformity correction for dystrophic NF-1 curves. Coronal and sagittal Cobbs angles, apical rotation, and the presence of dystrophic features were evaluated before surgery. Postoperatively, sagittal, coronal, and axial correction, implant position, and implant densities were evaluated. The decline in curve correction and implant-related complications were evaluated at follow-up. Clinical outcomes were evaluated using the Scoliosis Research Society-22 revised index. Results: This study involved 50 patients with a mean age of 13.6 years and a mean follow-up duration of 5.52 years. With a mean coronal flexibility of 18.7%, the mean apical vertebral rotation (AVR), preoperative coronal Cobb angle, and sagittal kyphosis were 27.4°, 64.01°, and 47.70°, respectively. The postoperative mean coronal Cobb angle was 30.17° (p<0.05), and the sagittal kyphosis angle was 25.4° (p<0.05). The average AVR correction rate was 41.3%. The correction remained significant at the final mean follow-up, with a coronal Cobb angle of 34.14° and sagittal kyphosis of 25.02° (p<0.05). The average implant density was 1.41, with 46% of patients having a high implant density (HID). The HID had a markedly higher mean curve correction (29.30° vs. 38.05°, p<0.05) and a lower mean loss of correction (5.7° vs. 3.8°, p<0.05). Conclusions: Utilizing computer-assisted navigation, hybrid instrumentation, and multiple anchor point technique and attaining high implant densities, this study demonstrates successful outcomes following posterior-only surgical correction of dystrophic scoliosis in patients with NF-1. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective observational study. Purpose: To analyze the effect of low-density (LD) strategic pedicle screw fixation on the correction of coronal and sagittal parameters in adolescent idiopathic scoliosis (AIS) patients. Overview of Literature: LD screw fixation achieves favorable coronal correction, but its effect on sagittal parameters is not well established. AIS is often associated with decreased thoracic kyphosis (TK), and the use of multi-level pedicle screws may result in further flattening of the sagittal profile. Methods: A retrospective analysis was performed on 92 patients with AIS to compare coronal and sagittal parameters preoperatively and at 2-year follow-up. All patients underwent posterior correction via LD strategic pedicle screw fixation. Radiographs were analyzed for primary Cobb angle (PCA), coronal imbalance, cervical sagittal angle (CSA), TK, lumbar lordosis (LL), pelvic incidence, pelvic tilt (PT), sacral slope (SS), C7 plumb line, spino-sacral angle, curve flexibility, and screw density. Results: PCA changed significantly from 57.6°±13.9° to 19°±8.4° (p <0.0001) with 67% correction, where the mean curve flexibility was 41% and screw density was 68%. Regional sagittal parameters did not change significantly, including CSA (from 10.76° to 10.56°, p =0.893), TK (from 24.4° to 22.8°, p =0.145), and LL (from 50.3° to 51.1°, p =0.415). However, subgroup analysis of the hypokyphosis group (<10°) and the hyperkyphosis group (>40°) showed significant correction of TK (p <0.0001 in both). Sacro-pelvic parameters showed a significant decrease of PT and increase of SS, suggesting a reduction in pelvic retroversion SS (from 37° to 40°, p =0.0001) and PT (from 15° to 14°, p =0.025). Conclusions: LD strategic pedicle screw fixation provides favorable coronal correction and improves overall sagittal sacro-pelvic parameters. This technique does not cause significant flattening of TK and results in a favorable restoration of TK in patients with hypokyphosis or hyperkyphosis. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective case series. Purpose: To assess safety and efficacy of single stage, posterior stabilisation and anterior cage reconstruction through the transforaminal or lateral extra-cavitary route for Andersson lesions. Overview of Literature: Pseudoarthrosis in ankylosing spondylitis (Andersson lesion, AL) can cause progressive kyphosis and neurological deficit. Management involves early recognition and surgical stabilisation in patients with instability. However, the need and safety of anterior reconstruction of the vertebral body defect remains unclear. Methods: Twenty consecutive patients with AL whom presented with instability back pain and or neurological deficit were managed by single stage posterior approach with long segment pedicle screw fixation and anterior vertebral reconstruction. Radiological evaluation included- the regional kyphotic angle, measurement of anterior defect in computed tomography (CT) scan and the spinal cord status in magnetic resonance imaging. Radiological outcomes were assessed for fusion and kyphosis correction. Functional outcomes were assessed with visual analogue scale (VAS), ankylosing spondylitis quality of life (ASQoL) and Oswestry disability index (ODI). Results: The mean age of the patients was 50.1 years (male, 18; female, 2). The levels affected include thoracolumbar (n=12), lower thoracic (n=5) and lumbar (n=3) regions. The mean level of fixation was 6.2±2.4 vertebrae. The mean anterior column defect was 1.6±0.6 cm. The mean surgical duration, blood loss and hospital stay were 112 minutes, 452 mL and 6.2 days, respectively. The mean follow-up was 2.1 years. At final follow up, VAS for back pain improved from 8.2 to 2.4 while ODI improved from 62.7 to 18.5 (p <0.05) and ASQoL improved from 14.3±2.08 to 7.90±1.48 (p <0.05). All patients had achieved radiological union at a mean 7.2±4.6 months. The mean regional kyphotic angle was 27° preoperatively, 16.7° postoperatively and 18.1° at the final follow-up. Conclusions: Posterior stabilisation and anterior reconstruction with cage through an all-posterior approach is safe and can achieve good results in Andersson lesions. [ABSTRACT FROM AUTHOR]

Late onset paraplegia is a rare complication of spinal tuberculosis. Disease reactivation and cord compression by internal gibbus are the common causes for neurological deficit. We report a patient with post-tubercular kyphotic deformity in whom the late onset paraplegia is caused by ossified ligamentum flavum above the level of kyphotic deformity. The deficit was attributable to the ossified ligamentum flavum and she recovered completely following posterior decompression and instrumented posterolateral fusion. To the best of our knowledge, this is the first report of this unusual cause of late onset paraplegia. [ABSTRACT FROM AUTHOR]

Background context Traditional short-segment fixation of unstable thoracolumbar injuries can be associated with progressive kyphosis and implant failure. Load sharing classification (LSC) recommends supplemental anterior reconstruction for fractures of score 7 or greater. Posterior fixation including the fractured vertebra (PFFV) has biomechanical advantages over conventional short-segment fixation. However, its efficacy in severe thoracolumbar injuries (LSC≥7) has not been studied. Purpose To study the clinical, functional, and radiologic results of PFFV for severe, unstable thoracolumbar injuries (LSC≥7) at a minimum of 2 years. Study design A retrospective review of case records. Patient sample Thirty-two patients with an unstable burst fracture of LSC≥7 treated with PFFV were included. Outcome measures They included clinical outcomes: American Spinal Injury Association grade, visual analog scale (VAS), Oswestry Disability Index (ODI); and radiologic measures: segmental kyphosis angle, vertebral wedge angle, and percentage loss of anterior and posterior vertebral height. Methods Thirty-two patients with LSC≥7 who had undergone PFFV, with a minimum follow-up of 2 years were studied for demographic, injury, and surgical details. Clinical and radiologic outcomes were measured before surgery and at 6, 12, and 24 months postoperatively. The presence of screw breakage, screw pullout, peri-implant loosening, and rod breakage were considered as criteria for implant failure. Results None of the patients had postoperative implant failure at the final follow-up. The mean preoperative kyphosis angle was 22.9°±7.6°. This improved significantly to 9.2°±6.6° after surgery (p=.000). There was a loss of mean 2.4° (mean kyphosis angle of 11.6°±6.3°) at the final follow-up. The mean preoperative wedge angle was 23.0°±8.1°. This was corrected to 9.7°±6.2° (p=.000). There was a loss of kyphosis (mean 1.2°) in the follow-up period. The mean anterior and posterior vertebral height also showed significant improvements postoperatively, which were maintained at the final follow-up. The mean ODI and VAS scores at the end of 2 years were 17.5% and 1.6, respectively. Conclusions Reduction of unstable thoracolumbar injuries even with LSC≥7 can be achieved and maintained with the use of short-segment pedicle screw fixation including the fractured vertebra, avoiding the need for anterior reconstruction. In the current era of evolving concepts of fracture fixation, the relevance of LSC in the management of unstable burst fractures is questionable. [ABSTRACT FROM AUTHOR]