Morphometric Evaluation of Occipital Condyles: Defining Optimal Trajectories and Safe Screw Lengths for Occipital Condyle-Based Occipitocervical Fixation in Indian Population

Study DesignComputed tomographic (CT) morphometric analysis.PurposeTo assess the feasibility and safety of occipital condyle (OC)-based occipitocervical fixation (OCF) in Indians and to define anatomical zones and screw lengths for safe screw placement.Overview of LiteratureLimitations of occipital squama-based OCF has led to development of two novel OC-based OCF techniques.MethodsMorphometric analysis was performed on the OCs of 70 Indian adults. The feasibility of placing a 3.5-mm-diameter screw into OCs was investigated. Safe trajectories and screw lengths for OC screws and C0–C1 transarticular screws without hypoglossal canal or atlantooccipital joint compromise were estimated.ResultsThe average screw length and safe sagittal and medial angulations for OC screws were 19.9±2.3 mm, ≤6.4°±2.4° cranially, and 31.1°±3° medially, respectively. An OC screw could not be accommodated by 27% of the population. The safe sagittal angles and screw lengths for C0–C1 transarticular screw insertion (48.9°±5.7° cranial, 26.7±2.9 mm for junctional entry technique; 36.7°±4.6° cranial, 31.6±2.7 mm for caudal C1 arch entry technique, respectively) were significantly different than those in other populations. The risk of vertebral artery injury was high for the caudal C1 arch entry technique. Screw placement was uncertain in 48% of Indians due to the presence of aberrant anatomy.ConclusionsThere were significant differences in the metrics of OC-based OCF between Indian and other populations. Because of the smaller occipital squama dimensions in Indians, OC-based OCF techniques may have a higher application rate and could be a viable alternative/salvage option in selected cases. Preoperative CT, including three-dimensional-CT-angiography (to delineate vertebral artery course), is imperative to avoid complications resulting from aberrant bony and vascular anatomy. Our data can serve as a valuable reference guide in placing these screws safely under fluoroscopic guidance

Analysis of Spinopelvic Parameters with L5 as the New Sacrum after Fusion in High-Grade Spondylolisthesis: A Possible Explanation for Satisfactory Results with Fusion

Study DesignRetrospective case series.PurposeTo correlate functional outcomes with spinopelvic parameters in patients with high-grade spondylolisthesis (HGS) treated with instrumented in-situ surgery or reduction and fusion.Overview of LiteratureSatisfactory functional outcomes are reported with reduction and in-situ fusion strategies in HGS. However, reasons for this are unclear. We hypothesize that following lumbosacral fusion, the L5 becomes part of the sacrum, which improves spinopelvic parameters, resulting in equivalent functional outcomes in both surgical methods.MethodsTwenty-six patients undergoing HGS (reduction group A, 13; in-situ group B, 13) were clinically evaluated using the Oswestry Disability Index (ODI), short form-12 (SF-12), and Visual Analogue Scale (VAS) scores. Spinopelvic parameters, including pelvic incidence, pelvic tilt (PT), sacral slope (SS), lumbar lordosis (LL), lumbosacral kyphosis (LSK) angle, and sacrofemoral distance (SFD) were measured preoperatively from S1 and postoperatively from L5 as the new sacrum at 1 year follow-up. Sagittal alignment was assessed using the sagittal vertical axis.ResultsBoth groups were comparable in terms of age, sex, severity of slip, and preoperative spinopelvic parameters (p>0.05). Postoperative VAS, SF-12, and ODI scores significantly improved in both groups (p0.05).ConclusionsAfter fusion, the L5 becomes the new sacrum and influences spinopelvic parameters to change favorably. This possibly explains why reduction and in-situ fusion achieve equivalent functional outcomes in HGS

Reciprocal Changes in Sagittal Alignment in Adolescent Idiopathic Scoliosis Patients Following Strategic Pedicle Screw Fixation

Study DesignRetrospective observational study.PurposeTo 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 LiteratureLD 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.MethodsA 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.ResultsPCA changed significantly from 57.6°±13.9° to 19°±8.4° (p 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).ConclusionsLD 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

Analysis of Postoperative Clinical Outcomes in Cervical Myelopathy due to Ossification of Posterior Longitudinal Ligament Involving C2

Study Design Retrospective study. Purpose To investigate the radiological phenotype, patient and surgery-related risk factors influencing postoperative clinical outcome for cervical myelopathy caused by ossification of the posterior longitudinal ligament involving C2 following posterior instrumented laminectomy and fusion. Overview of Literature Ossified posterior longitudinal ligament (OPLL) is caused by ectopic ossification of the posterior longitudinal ligament. It can cause neurological impairment and severe disability. For multilevel cervical OPLL, studies have shown good neurological recovery following cord decompression via either an anterior or posterior approach. There is, however, a lacunae in the literature regarding the outcomes of patients with OPLL extending to C2 and above (C2 [+]). Methods We retrospectively studied 61 patients with C2 (+) OPLL who had posterior instrumented laminectomy and fusion at Ganga Hospital, Coimbatore between July 2011 and January 2021, with a minimum follow-up of 2 years. Data on demographics, clinical outcomes, radiology, and post-surgical outcomes were gathered. Results Among 61 patients, 56 were males and five were females. The OPLL pattern was mixed in 32 cases (52.5%), continuous in 26 cases (42.6%), segmental in two cases (3.3%), and circumscribed in one patient (1.6%). All of our patients showed signs of neurological improvement after a 24-month follow-up. The mean preoperative modified Japanese Orthopaedic Association (mJOA) score was 10.6 (range, 5–11) and the postoperative mJOA score was 15.8 (range, 12–18). The recovery rate was >75% in 27 patients (44.6%), >50% in 32 patients (52.5%), and >25% in two patients (3.3%). The average recovery rate was 71% (range, 33%–100%). The independent risk factor for predicting recovery rate is the preoperative mJOA score. Conclusions In C2 (+) OPLL, posterior instrumented decompression and fusion provide a relatively safe approach and satisfactory results

Prevalence, Patterns, and Genetic Association Analysis of Modic Vertebral Endplate Changes

Study DesignA prospective genetic association study.PurposeThe etiology of Modic changes (MCs) is unclear. Recently, the role of genetic factors in the etiology of MCs has been evaluated. However, studies with a larger patient subset are lacking, and candidate genes involved in other disc degeneration phenotypes have not been evaluated. We studied the prevalence of MCs and genetic association of 41 candidate genes in a large Indian cohort.Overview of LiteratureMCs are vertebral endplate signal changes predominantly observed in the lumbar spine. A significant association between MCs and lumbar disc degeneration and nonspecific low back pain has been described, with the etiopathogenesis implicating various mechanical, infective, and biochemical factors.MethodsWe studied 809 patients using 1.5-T magnetic resonance imaging to determine the prevalence, patterns, distribution, and type of lumbar MCs. Genetic association analysis of 71 single nucleotide polymorphisms (SNPs) of 41 candidate genes was performed based on the presence or absence of MCs. SNPs were genotyped using the Sequenome platform, and an association test was performed using PLINK software.ResultsThe mean age of the study population (n=809) was 36.7±10.8 years. Based on the presence of MCs, the cohort was divided into 702 controls and 107 cases (prevalence, 13%). MCs were more commonly present in the lower (149/251, 59.4%) than in the upper (102/251, 40.6%) endplates. L4–5 endplates were the most commonly affected levels (30.7%). Type 2 MCs were the most commonly observed pattern (n=206, 82%). The rs2228570 SNP of VDR (p=0.02) and rs17099008 SNP of MMP20 (p=0.03) were significantly associated with MCs.ConclusionsGenetic polymorphisms of SNPs of VDR and MMP20 were significantly associated with MCs. Understanding the etiopathogenetic mechanisms of MCs is important for planning preventive and therapeutic strategies

Intra-operative computer navigation guided cervical pedicle screw insertion in thirty-three complex cervical spine deformities

Background: Cervical pedicle screw fixation is challenging due to the small osseous morphometrics and the close proximity of neurovascular elements. Computer navigation has been reported to improve the accuracy of pedicle screw placement. There are very few studies assessing its efficacy in the presence of deformity. Also cervical pedicle screw insertion in children has not been described before. We evaluated the safety and accuracy of Iso-C 3D-navigated pedicle screws in the deformed cervical spine. Materials and Methods: Thirty-three patients including 15 children formed the study group. One hundred and forty-five cervical pedicle screws were inserted using Iso-C 3D-based computer navigation in patients undergoing cervical spine stabilization for craniovertebral junction anomalies, cervico-thoracic deformities and cervical instabilities due to trauma, post-surgery and degenerative disorders. The accuracy and containment of screw placement was assessed from postoperative computerized tomography scans. Results: One hundred and thirty (89.7%) screws were well contained inside the pedicles. Nine (6.1%) Type A and six (4.2%) Type B pedicle breaches were observed. In 136 levels, the screws were inserted in the classical description of pedicle screw application and in nine deformed vertebra, the screws were inserted in a non-classical fashion, taking purchase of the best bone stock. None of them had a critical breach. No patient had any neurovascular complications. Conclusion: Iso-C navigation improves the safety and accuracy of pedicle screw insertion and is not only successful in achieving secure pedicle fixation but also in identifying the best available bone stock for three-column bone fixation in altered anatomy. The advantages conferred by cervical pedicle screws can be extended to the pediatric population also

Role of robotics and spinal navigation in reducing surgical complications

Spine surgery has witnessed exponential technological innovation over the past few decades to overcome the challenges of complex surgeries, reduce complications, and increase safety. Advancements have occurred in biologics, implants, operative techniques, and equipment such as navigation and surgical robotics. In addition to patient safety, these technologies protect the operating personnel from the harmful effects of radiation. Navigation provides simultaneous and multiplanar visualization of anatomy, real-time feedback of instruments, and implant position, which, in turn, improves the accuracy and hand–eye coordination of the surgeon. Robotics further improves outcomes by reducing human error through increased precision in execution, indefatigability, motion scaling, and tremor filtration via mechanical actuation. This review provides an overview of the current navigation and robotic systems in spine surgeries and their role in the safety and prevention of surgical complications

The Effectiveness of Noninvasive Positive Pressure Ventilation in Subarachnoid Pleural Fistula: A Case Report and Literature Review

Subarachnoid pleural fistula (SPF) is an aberrant communication between the pleural cavity and subarachnoid space, resulting in uncontrolled cerebrospinal fluid drainage. The negative pressure of the pleural cavity creates a continuous suctioning effect, thereby impeding the spontaneous closure of these fistulas. Dural tears or punctures in cardiothoracic procedures, spinal operations, and trauma are known to cause such abnormal communications. Failure to recognize this entity may result in sudden neurological or respiratory complications. Hence, a high index of suspicion is required for early diagnosis and prompt management. Noninvasive positive pressure ventilation has been described to be effective in managing such fistulas, thus mitigating the high morbidity associated with exploratory surgery for primary repair. Herein, we describe the typical presentation of SPF and the clinical course, treatment, and follow-up of a patient who sustained SPF following anterior thoracic spinal surgery

Lumbar Intraspinal Osteolipoma Presenting as Cauda Equina Syndrome: A Case Report and Review of Literature

Introduction. Osteolipomas are uncommon variants of lipoma. These lesions have been usually reported to arise from the oral cavity, brain, and neck and scarcely from the knee and thigh. Intraspinal osteolipomas are rare. A single case of intraspinal osteolipoma has been reported in the cervical and thoracic spine in the literature. To our knowledge, there is no report of osteolipomas in the lumbar spine. Case Presentation. We report a very rare case of a solitary lumbar intraspinal osteolipoma, presenting as a cauda equina syndrome. The intraspinal osteolipoma was excised en bloc and fusion was performed as it required partial resection of the facet joint within 24 hours of presentation. He has since then improved neurologically, and there has been no recurrence of the lesion so far. The clinical presentation, radiological characteristics, treatment course, and histopathological features of this lesion along with the clinical outcomes and a pertinent literature review were done and have been discussed. Discussion. The heterogeneous signal intensity of the lesion in MRI differentiates it from other dural-based lesions, and this should raise suspicion of an osteolipoma, which warrants a CT. Although intraspinal osteolipomas are benign lesions and generally have good prognosis, they need to be removed en bloc as they may result in rapid neurological deterioration

Factors Influencing Postoperative Urinary Retention Following Elective Posterior Lumbar Spine Surgery: A Prospective Study

Study Design Prospective observational study. Purpose To determine the incidence of postoperative urinary retention (POUR) in patients undergoing elective posterior lumbar spine surgery and identify the risk factors associated with the development of POUR. Overview of Literature POUR following surgery can lead to detrusor dysfunction, urinary tract infections, prolonged hospital stay, and a higher treatment cost; however, the risk factors for POUR in spine surgery remain unclear. Methods A prospective, consecutive analysis was conducted on patients undergoing elective posterior lumbar surgery in the form of lumbar discectomy, lumbar decompression, and single-level lumbar fusions during a 6-month period. Patients with spine trauma, preoperative neurological deficit, previous urinary disturbance/symptoms, multiple-level fusion, and preoperative catheterization were excluded from the study. Potential patient- and surgery-dependent risk factors for the development of POUR were assessed. Univariate analysis and a multiple logistical regression analysis were performed. Results A total of 687 patients underwent posterior lumbar spine surgery during the study period; among these, 370 patients were included in the final analysis. Sixty-one patients developed POUR, with an incidence of 16.48%. Significant risk factors for POUR were older age, higher body mass index (BMI), surgery duration, intraoperative fluid administration, lumbar fusion versus discectomy/ decompression, and higher postoperative pain scores (p<0.05 for all). Sex, diabetes, and the type of inhalational agent used during anesthesia were not significantly associated with POUR. Multiple logistical regression analysis, including age, BMI, surgery duration, intraoperative fluid administration, fusion surgery, and postoperative pain scores demonstrated a predictive value of 92% for the study population and 97% for the POUR group. Conclusions POUR was associated with older age, higher BMI, longer surgery duration, a larger volume of intraoperative fluid administration, and higher postoperative pain scores. The contribution of postoperative pain scores in the multiple regression analysis was a significant predictor of POUR