Microsurgical and Descriptive Three-Dimensional Analysis of the Subarticular Trigone: A Guidemap for Standardizing Lateral Recess Decompression.

Background Lateral recess decompression has remained a cornerstone spinal procedure for decades. Despite its popularity, a significant lack of evidence in the literature exists concerning microsurgical anatomy and pertinent surgical landmarks, resulting in non-standardized nomenclature, descriptions, and surgical approaches. Objective This study provides an in-depth microsurgical and descriptive analysis of the subarticular trigone (SAT), serving as an anatomical guide and a tool to foster consistency in nomenclature and standardization of surgical approaches. Methods We analyzed 35 high-resolution lumbar spine CT scans, employing three-dimensional (3D) processing techniques. The SAT is introduced to delineate the bony prominence enveloping the superiomedial quadrant of the pedicle. The SAT encompasses two zones: (1) a superior zone above the superior pedicular line, corresponding to the medial part of the body of the ascending facet (AF), and (2) an inferior zone between the superior and middle pedicular lines, corresponding to the root of the AF and the medial pars/superior lamina. The superior subarticular point (SSP) and medial subarticular point (MESP) serve as key reference landmarks. The SAT forms the roof of the lateral recess and the region requiring resection during decompression of the traversing root in this anatomical corridor. Various measurements, including SSP and MESP to lateral pars, tip of the facet and spino-laminar junction distance, mean width of the sublaminar ridge (SLR), and percentage of the facet that requires resection for adequate SAT decompression, were carried out. Results The mean distance of the SSP to the lateral pars ranges from 7 to 9.2 mm, to the tip of the descending from 9.3 to 10.1 mm, and to the spino-laminar junction from 6.7 to 8.1 mm. The MESP is located at a mean distance of 5.4-6.9 mm from the medial pedicular line. The mean width of the SLR varies from 18.6 to 29.4 mm. Finally, the percentage of total facet width that needs to be removed to adequately decompress the SAT extends from 32% at L4 to 36% at L1. Conclusions This study presents comprehensive insights into the surgical, descriptive, and correlative anatomy of the lateral recess, emphasizing the SAT. The extrapolated data offer a framework for achieving uniformity in surgical planning and advocate for standardized nomenclature.

Thoracolumbar Fractures: Comparing the Effect of Minimally Invasive Versus Open Schanz Screw Techniques on Sagittal Alignment.

STUDY DESIGN: This is a retrospective comparative cohort study. PURPOSE: This study aims to compare the effects of minimally invasive surgery (MIS) and open surgery (OS) on global sagittal alignment (GSA) in surgically managed thoracolumbar fractures. OVERVIEW OF LITERATURE: The optimal treatment of traumatic thoracolumbar fractures (TLF) remains controversial. Both MIS techniques with polyaxial screws and OS techniques with Schanz screws have gained widespread use. The effect of each technique on the global sagittal alignment has not been reported. METHODS: From 2014 to 2021, 22 patients with traumatic TLF underwent open posterior stabilization using an open transpedicular Schanz screw-rod construct and were compared to 15 patients who underwent minimally invasive surgery using a polyaxial percutaneous pedicle screw-rod construct. The reported radiological parameters measured on preoperative supine CT scan and immediate postop standing X-ray and on final follow-up whole spine standing X-rays included pelvic incidence (PI), pelvic tilt (PT), lumbar lordosis (LL), preoperative segmental kyphosis (Preop-K), immediate post-operative segmental kyphosis (postop-Ki), final post-operative segmental kyphosis (postop-Kf), sagittal-vertica-axis (SVA), and spino-sacral angle (SSA). RESULTS: The average age of the OS group was 42.5 years; 5 patients had AO type B, and 17 patients had AO type A (A3 and A4) fractures. The average follow-up was 16.8 months. The average radiological parameters were: PI = 54.9°, PI-LL = 3°, PT = 17.6°, preop-K = 16.2°, postop-Ki = 8.7°, final postop-Kf = 14.3°, SVA = 4.58 cm, and SSA = 101.8°. The average age of the MIS group was 43.4 years; 5 patients had AO type B, and 10 patients had AO type A fractures. The average follow-up was 25 months. The average radiological parameters were as follows: PI = 51°, PI-LL = 8°, PT = 18°, preop-K = 18.4°, postop-Ki = 11.6°, postop-Kf = 14.3°, SVA = 6.4 cm, SSA = 106°. CONCLUSION: The fixation technique did not significantly affect the final correction of the local kyphosis and global spine alignment parameters.

The influence of osteoporotic vertebral fractures on global sagittal alignment in elderly patients: a systematic review and meta-analysis.

BACKGROUND: Thoracic kyphosis, or loss of lumbar lordosis, is often equated with osteoporosis because vertebral fractures are assumed to be a major causative factor, in addition to degeneration related to age. Despite the few studies aiming to measure the natural change in global sagittal alignment (GSA) that occurs with advancing age, the overall effect of conservatively managed osteoporotic vertebral compression fractures (OVCF) on the GSA in the elderly remains poorly understood. OBJECTIVE: To systematically evaluate the relevant literature regarding the influence of OVCF on the GSA compared to patients of similar age without fractures using the following radiological parameters: Pelvic Incidence (PI), Pelvic Tilt (PT), Lumbar Lordosis (LL), Thoracic Kyphosis (TK), Sagittal Vertical Axis (SVA) and Spino-sacral Angle (SSA). METHODS: A systematic review of the English language literature dating up until October 2022, was undertaken utilizing the PRISMA guidelines. RESULTS: Of a total of 947 articles, 10 studies met the inclusion criteria (4 Level II, 4 level III and 2 level IV evidence) and were subsequently analyzed. Overall, 584 patients (8 studies) of mean age 73.7 years (69.3-77.1) had acute OVCF of one or more vertebra that were managed conservatively. The male to female ratio was 82:412. Five studies mentioned the number of fractured vertebrae, with a total of 393 in 269 patients (average of 1.4 fractured vertebrae per patient). Their pre-operative radiological parameters on standing X-rays showed a mean PI of 54.8°, PT 24°, LL 40.8°, TK 36.5°, PI-LL 14°, SVA 4.8 cm, and SSA 115°. In addition, 437 patients were used as a control group with osteoporosis without fractured vertebrae, (6 studies) with an average age of 72.4 years (67-77.8) and male to female ratio of 96:210 (5 studies). They all had upright X-rays to assess their global sagittal alignments. Radiological parameters showed an average PI of 54.3°, PT 17.3°, LL 43.4°, TK 31.25°, PI-LL 10.95°, SVA 1.27 cm and SSA 125°. A statistical analysis comparing the OVCF group with the control group (4 studies), showed a significant increase in PT of 5.97° (95%CI 2.63, 9.32; P < 0.0005), a significant increase in TK by 8.28° (95%CI 2.15, 14.4; P < 0.008), an increase in PI-LL by 6.72° (95%CI 3.39, 10.04; P < 0.0001), an increase in SVA by 1.35 cm (95%CI 0.88, 1.83; P < 0.00001), and a decrease in SSA by 10.2° (95%CI 10.3, 23.4; P < 0.00001). CONCLUSION: Osteoporotic vertebral compression fractures managed conservatively appear to be a significant causate factor of global sagittal imbalance.

Do intraoperative radiographs predict final lumbar sagittal alignment following single-level transforaminal lumbar interbody fusion?

OBJECTIVE The study aimed to determine if the intraoperative segmental lordosis (as calculated on a cross-table lateral radiograph following a single-level transforaminal lumbar interbody fusion [TLIF] for degenerative spondylolisthesis/low-grade isthmic spondylolisthesis) is maintained at discharge and at 6 months postsurgery. METHODS The authors reviewed images and medical records of patients ≥ 16 years of age with a diagnosis of an isolated single-level, low-grade spondylolisthesis (degenerative or isthmic) with symptomatic spinal stenosis treated between January 2008 and April 2014. Age, sex, surgical level, surgical approach, and facetectomy (unilateral vs bilateral) were recorded. Upright standardized preoperative, early, and 6-month postoperative radiographs, as well as intraoperative lateral radiographs, were analyzed for the pelvic incidence, segmental lumbar lordosis (SLL) at the TILF level, and total LL (TLL). In addition, the anteroposterior position of the cage in the disc space was documented. Data are presented as the mean ± SD; a p value < 0.05 was considered significant. RESULTS Eighty-four patients were included in the study. The mean age of patients was 56.8 ± 13.7 years, and 46 patients (55%) were men. The mean pelvic incidence was 59.7° ± 11.9°, and a posterior midline approach was used in 47 cases (56%). All TLIF procedures were single level using a bullet-shaped cage. A bilateral facetectomy was performed in 17 patients (20.2%), and 89.3% of procedures were done at the L4-5 and L5-S1 segments. SLL significantly improved intraoperatively from 15.8° ± 7.5° to 20.9° ± 7.7°, but the correction was lost after ambulation. Compared with preoperative values, at 6 months the change in SLL was modest at 1.8° ± 6.7° (p = 0.025), whereas TLL increased by 4.3° ± 9.6° (p < 0.001). The anteroposterior position of the cage, approach, level of surgery, and use of a bilateral facetectomy did not significantly affect postoperative LL. CONCLUSIONS Following a single-level TLIF procedure using a bullet-shaped cage, the intraoperative improvement in SLL is largely lost after ambulation. The improvement in TLL over time is probably due to the decompression part of the procedure. The approach, level of surgery, bilateral facetectomy, and position of the cage do not seem to have a significant effect on LL achieved postoperatively.

The surgical management of atlanto-axial subluxation in juvenile rheumatoid arthritis.

Juvenile idiopathic arthritis (JIA) is a chronic condition affecting patients <16 years of age and can be associated with substantial morbidity. Atlanto-axial subluxation (AAS) is a known complication of JIA and can result in pain, reduced neck motion and neurological compromise. In this paper, we present the case of a 10-year old suffering with JIA and significant AAS; we discuss the management options and present the approach and outcome of treatment for this case.

Anterior column reconstruction with PMMA: an effective long-term alternative in spinal oncologic surgery.

A number of anterior reconstruction options are available in patients managed for symptomatic metastatic spinal column disease. Polymethylmethacrylate (PMMA) has been traditionally used as a reconstruction option in patients with limited life expectancy as an anterior fusion is not expected. In this article, we present the outcome of a 13-year follow-up of a long anterior reconstruction using PMMA of the upper thoracic spine in a myelopathic female secondary to a compressive breast metastasis affecting the upper 4 thoracic vertebrae. We discuss the use of PMMA in spinal oncological surgery and review the evidence pertinent to its use.

Does transcranial stimulation for motor evoked potentials (TcMEP) worsen seizures in epileptic patients following spinal deformity surgery?

PURPOSE: To investigate the effect of Transcranial Motor Evoked Potentials (TcMEP) in increasing the severity or frequency of post-operative seizures in patients undergoing deformity corrective spine surgery with a known history of seizures pre-operatively. METHODS: The information on all patients with history of epilepsy/seizures who underwent spinal TcMEP cord monitoring for deformity correction surgery was retrospectively collected through a review of the hospital notes. The benefits of TcMEP in the early detection of potential cord ischemia were deemed by the operating surgeon to outweigh the increased risks of seizures, tongue biting, etc. Data on age, gender, pre-operative diagnosis, curve type, intra-operative monitoring alerts, duration of hospital stay, and post-operative in-hospital seizures were collected. Additionally, the patients were contacted following discharge and data on any change in the frequency of the seizures or an alteration in seizure-related medication post-operatively was also collected. RESULTS: The records of 449 consecutively monitored patients were reviewed and 12 (2.7 %) patients with a history of seizures pre-operatively were identified. The mean age was 23 (9-59) years, 7 females, 11 scoliosis corrections (4 neuromuscular, 1 degenerative, 6 idiopathic adolescent), and one sagittal balance correction surgery. Intra-operatively, all patients had TcMEP monitoring, were catheterised, and had no neuromonitoring alerts or record of tongue biting or laceration. Post-operatively, the mean hospital stay was 12 (4-25) days with no recorded seizures. At a mean of 23 (12-49) months post-discharge, none of the patients reported a worsening of seizures (pattern or frequency) or required an alteration in the seizure-related medications. CONCLUSION: TcMEP does not appear to trigger intra-operative or post-operative seizures and is not associated with deterioration in the seizure control of patients suffering seizures pre-operatively.

Cervical spondylotic myelopathy: the prediction of outcome following surgical intervention in 93 patients using T1- and T2-weighted MRI scans.

INTRODUCTION: Cervical spondylotic myelopathy (CSM) can lead to significant disability through a spectrum of clinical manifestations ranging from dexterity loss to more profound weakness, incontinence and paralysis. AIM: To determine the outcome of surgical decompression for CSM and investigate pre-operative predictors of outcome. METHODS: Prospectively collected data on all patients who underwent decompressive surgery for CSM and completed 12-month follow-up were reviewed. Data on age, MRI T1 and T2 signal changes pre-operatively, surgical approach and the Nurick's Myelopathy Grade (NMG) was analysed pre-operatively and 1 year post-surgery. RESULTS: Data on 93 consecutive patients who underwent surgery for CSM were reviewed. Median age was 62 (23-94) years and 59% were male. The median follow-up was 37 (17-88) months. The approach was anterior in 38 (42%) patients, posterior in 55 (58%); improvement was not significantly different when the two groups were compared. The number of levels decompressed increased with age (p value <0.0001). The group with a pre-operatively high signal on T1-weighted MRI images [n = 28 (30%)] was associated with less neurological recovery post-operatively compared to the patients with a normal T1 cord signal. None of the patients deteriorated neurologically post-operatively, while 66% improved by at least one NMG. CONCLUSION: Surgical decompressions for CSM stop the progress of symptoms at 12 months post-surgery and may result in a significant improvement of NMG in two-thirds of the patients. Changes in the T1-weighted MRI images predict worse outcomes following surgery.

The surgical management of metastatic spinal tumors based on an Epidural Spinal Cord Compression (ESCC) scale.

BACKGROUND CONTEXT: There have been no previous studies looking at the outcome of surgical decompression (+/-stabilization) for various grades of epidural spinal cord compression (ESCC) due to spinal metastases. PURPOSE: The aim of this study was to determine the outcome of surgical treatment in patients with ESCC using the Bilsky six-point scale. STUDY DESIGN/SETTING: This was a retrospective cohort review of prospectively collected data. PATIENT SAMPLE: A consecutive series of 101 patients managed over the period of 3 years for ESCC due to spinal metastases in a tertiary spine surgery referral unit were included. METHODS: Data on age, gender, revised Tokuhashi score, preoperative Frankel grade, tumor histology, magnetic resonance imaging scan-based Bilsky cord compression grade, postoperative Frankel grade at last follow-up, complications, and survivorship were collected. OUTCOME MEASURES: Frankel grading system for function was used to evaluate the patient's preoperative and postoperative neurologic status. Patient survival and postoperative complications were also collected. RESULTS: Average patient age was 64.7 years (13-88 years): 62 males and 39 females. Mean follow-up was 7.3 months (3-23.3 months). Most primary tumors were in prostate, breast, renal, lung, and the blood dyscrasias. Within the lower grade of compression (Group 1; Bilsky Grades 0,1a, 1b, and 1c; n=40), 29 patients (72.5%) had no improvement in Frankel grade, seven patients (17.5%) improved, whereas four patients (10%) deteriorated neurologically after surgery. Within the higher compression grade (Group 2; Bilsky Grades 2 and 3; n=61), 37 patients (60%) did not experience neurologic change, 20 (33%) improved, whereas neurology worsened in four patients (7%). When compared with Group 2 patients, Group 1 patients had better preoperative Frankel scores but a greater number of patients in Group 2 improved their Frankel scores significantly postoperatively. The mean revised Tokuhashi score for Groups 1 and 2 was 10 and 9.1, respectively (p=.1). The complication rate for Groups 1 and 2 was 25% and 42.6%, respectively (p=.052). Survival analysis showed no difference between the groups (Group 1: median 376 days [12-1052]; Group 2: median 326 days [12-979]; p=.62). CONCLUSIONS: Surgery can achieve improvements in neurology even in higher grades of cord compression. There is a trend toward more complications and worse survival with spinal surgery in patients with higher grades of compression.