Spinal Stenosis

Following the institutional review board approval for the study (number: 119/2019; Muğla Sıtkı Koçman University Ethical Committee), a retrospective cohort analysis was performed using the medical records of patients. For the current study, patient consent is not required. All procedures executed involving human participants were in accordance with the ethical standards of the institutional ethical committee and with the 1964 Helsinki declaration.
A total of 146 patients who applied to the neurosurgery outpatient clinic with a recent abdominal CT (max three months) because of a lower back pain complaint were included in the study. Patients with a previous history of surgery or a vertebral fracture were excluded. After excluded patients, a total of 146 patients were included in the study, of whom 90 were female (61.6%) and 56 were male (38.4%). The mean age of the patients was 51.42±13.91 (20-82) years.
Lumbar vertebra CT scans of all patients were reviewed retrospectively. CT images at the level from L3-L4 intervertebral disc were analyzed for body composition of fat tissue and muscle mass volume through the dedicated CT software (Syngo.via, SOMATOM Definition Flash: Siemens Healthcare, Forchheim, Germany). The L3-L4 level was selected in sagittal reformat CT images with the software (Figure 1).
The density range of -200, -40 HU was selected for the fat density measurement in the cross-section with the "region grooving" application in the angled axial images obtained parallel to the disc plane at this level. First, the fat volume in the whole section was measured (visceral and subcutaneous). Then, only the visceral adipose tissue volume was calculated by drawing borders to exclude subcutaneous adipose tissue (Figure 2). The subcutaneous fat tissue volume was obtained by subtracting the visceral fat tissue volume from the total fat volume (Figure 3).
With the same application, muscle density was selected and paravertebral muscle tissue volume was calculated (bilateral musculus psoas major, musculus quadratus lumborum, musculus iliocostalis, musculus longissimus, musculus multifidus volumes). A Spearman correlation model was used to analyze visceral adiposity, subcutaneous fat, and muscle mass.
In CT images, each intervertebral disc space was evaluated in terms of the presence of osteophytes, loss of disc height, sclerosis in the end plates, and spinal stenosis (spinal canal narrowing under 15 mm AP diameter) to investigate the presence of degeneration. Each level was scored according to the presence of findings, with 1 point for the presence of osteophytes, loss of disc height, sclerosis in the end plates, and spinal stenosis. The total score at all levels (L1-S1) was calculated for each patient.
Statistical analyses were performed using IBM SPSS version 20.0 software (IBM Corp., Armonk, NY). The conformity of the data to normal distribution was assessed using the Shapiro-Wilk test. Normally distributed variables were presented as mean±standard deviation and those not showing normal distribution as median (minimum-maximum) values. Categorical variables were presented as numbers (n) and percentages (%). The Spearman's rank correlation coefficient test was used to determine the correlation between the measured parameters in various vertebral pathologies. Continuous variables were compared using the Mann-Whitney U test. The receiver operating characteristic (ROC) analysis was used to detect the area under the curve (AUC) and define the cutoff values with their sensitivities and specificities of the measurements. An alpha value of p<0.05 was accepted as statistically significant.

This study was approved by the Committee of Medical Ethics and the Institutional Review Boards of our hospital (2022, Reviewed, No. 13).We retrospectively reviewed the clinical data of patients who underwent UBE-ULBD and OLD in a single academic institution between February 2019 and July 2021. Written informed consent was waived due to the retrospective nature of the study. Data for OLD were derived from 2019 to 2021, whereas data for UBE-ULBD were from 2020 to 2021 when the UBE-ULBD technique was used for severe DLSS. The inclusion criteria were: (1) aged >18 years; (2) Single level DLSS; (3) minimum of 1 year of follow-up; (4) Schizas Grade C or D (severe central stenosis) on preoperative MRI [Grade A, cerebrospinal fluid (CSF) is clearly visible inside the dural sac; Grade B, rootlets occupy the entire dural sac but can still be individualized; Grade C, rootlets cannot be individualized with posterior epidural fat and invisible CSF; Grade D, rootlets cannot be individualized without posterior epidural fat]; (5) All patients had symptoms associated with lower limb neurological impairment with failure to respond to conservative treatment for at least 3 month. Patients were excluded for the following reasons: (1) Previous history of lumbar surgery; (2) Presence of lumbar spondylolisthesis, lumbar instability, or degenerative deformity with Cobb angle >20°;(3) Spinal stenosis caused by lumbar tumors, tuberculosis or fractures; (4) Severe illness affecting anesthesia or surgery; (5) The follow-up period was shorter than 1 year. Consequently, this study included 51 patients (operated at 51 vertebral levels; UBE-ULBD group) who underwent unilateral biportal endoscopy unilateral laminectomy bilateral decompression (UBE-ULBD) and 59 patients (operated at 59 vertebral levels; OLN group) who underwent conventional open lumbar discectomy (OLD).All surgeries were performed by a single spinal surgeon.

This study used a retrospective design and a convenience sampling method. It included patients who underwent standing film and MRI examinations and were diagnosed with DLD at this hospital between 1 January 2015 and 1 June 2016. The Institutional Review Board approved the study (approval number: ID:2014–426), and each patient gave written consent. The inclusion criteria were as follows: (1) patients with lumbar spinal stenosis, lumbar disc hernia or lumbar spondylolisthesis; (2) age ≥ 50 years; (3) no underlying congenital or neurological abnormalities; (4) no leg length discrepancy > 2 cm; (5) Cobb angle < 20°; (6) no more than 1 month between the standing x-ray and MRI. The exclusion criteria were as follows: (1) previous spinal surgery; (2) incomplete clinical and imaging data; (3) nondegenerative spine pathologies; (4) fracture of a vertebra. The standing radiographs were taken with a digital flat panel detector system, and the MRI was obtained with a 1.5 T MRI scanner (Siemens, Germany). All radiographic and MRI images were assessed by means of the picture archiving and communication system (PACS) workstation of our hospital.