Postoperative Paraspinal Muscles Assessment After Endoscopic Stenosis Lumbar Decompression: Magnetic Resonance Imaging Study.

BACKGROUND CONTEXT: Conventional open lumbar decompression is a widely accepted procedure for degenerative lumbar disease. However, it is associated with morbidity due to damage to the paraspinal muscles and posterior ligamentous complex. Endoscopic spine surgery (ESS) is considered the least invasive type of spine surgery in modern times and was developed to minimize the iatrogenic injury to the paraspinal muscles. PURPOSE: Many studies are reported to estimate the paraspinal muscle damage after an open or minimal invasive spine surgery by radiological methods (magnetic resonance imaging [MRI] and computed tomography], biochemistry (creatinine phosphokinase level), or electrophysiology (electoneuromyography). The objectives of this study were to assess paraspinal muscles changes after lumbar endoscopic unilateral laminotomy with bilateral decompression (LE-ULBD) based on preoperative and 6-month postoperative MRIs. PATIENT SAMPLE: We studied 159 consecutive patients with lumbar degenerative disease who underwent LE-ULBD at a spine specialty hospital from 2018 to 2019. STUDY DESIGN: The current study was a single-center, single-surgeon, retrospective case study. OUTCOME MEASURES: Changes of paraspinal muscles after LE-ULBD measured on lumbar MRI. METHODS: Postoperative paraspinal muscles changes are evaluated on a picture archiving and communication system by measuring the cross-sectional area (CSA) of multifidus and erector spinae muscles along with the fatty infiltration of muscle on Kjaer's scale at the level of surgery on the ipsilateral and contralateral sides on T1W image. Correlations between imaging and visual analog scale (VAS) score for back, Oswestry Disability Index (ODI), and MacNab's criteria were examined in the preoperative and postoperative periods. RESULTS: Of the 159 patients included, 120 underwent a single level procedure and 39 a multilevel procedure. For single-level LE-ULBD group, mean (SD) preoperative, postoperative, and final follow-up VAS score (7.83 [1.37], 3.15 [0.67] and 2.19 [0.88]; P < 0.001) and ODI (74.09 [7.18], 27.88 [4.40], and 23.88 [4.56]; P < 0.001) improved significantly. Based on MacNab's criteria, the clinical result was excellent in 37 patients, good in 78 patients, and fair in 5 patients. For the multilevel LE-ULBD group, the mean (SD) preoperative, postoperative, and final follow-up VAS score (7.84 [1.38], 3.50 [0.60],and 2.44 [0.79]; P < 0.001) and ODI (74.1 [7.72], 31.30 [4.46], and 24.90 [4.75]; P < 0.001) also improved significantly . Based on MacNab's criteria, the clinical result was excellent in 6 patients, good in 31 patients, and fair in 2 patients.The functional CSA of paraspinal muscles for both groups showed no significant difference in the 6-month follow-up MRI. The fatty infiltration of paraspinal muscles significantly improved from 0.77 to 0.59 (P < 0.05) for the single level LE-ULBD group but not for the multilevel LE-ULBD group (P = 0.320). The mean dural sac CSA increased significantly for both groups (P < 0.001). CONCLUSION: Adequate neural decompression can be achieved with the preservation of paraspinal muscles after an ESS. Preservation of the paraspinal muscles along with the posterior ligamentous complex improves the stability of motion segment in the postoperative period, which ultimately results in better patient outcomes in related to postoperative pain and rehabilitation.Key.

Early results of full-endoscopic decompression of lumbar central canal stenosis by outside-in technique: A clinical and radiographic study.

ABSTRACT: Retrospective cohort study.Full-endoscopic decompression of lumbar spinal canal stenosis is being performed by endoscopic surgeons as an alternative to micro-lumbar decompression in the recent years. The outcomes of the procedure are reported by few authors only. The aim of this paper is to report the clinical and radiographic outcomes of full endoscopic lumbar decompression of central canal stenosis by outside-in technique at 1-year follow-up.We reviewed patients operated for lumbar central canal stenosis by full endoscopic decompression from May 2018 to November 2018. We analyzed the visual analogue scale scores for back and leg pain and Oswestry disability index at pre-op, post-op, and 1-year follow-up. At the same periods, we also evaluated disc height, segmental lordosis, whole lumbar lordosis on standing X-rays and canal cross sectional area at the affected level and at the adjacent levels on magnetic resonance imaging and the facet length and facet cross-sectional area on computed tomography scans. The degree of stenosis was judged by Schizas grading and the outcome at final follow-up was evaluated by MacNab criteria.We analyzed 32 patients with 43 levels (M:F = 14:18) with an average age of 63 (±11) years. The visual analogue scale back and leg improved from 5.4 (±1.3) and 7.8 (±2.3) to 1.6 (±0.5) and 1.4 (±1.2), respectively, and Oswestry disability index improved from 58.9 (±11.2) to 28 (±5.4) at 1-year follow-up. The average operative time per level was 50 (±16.2) minutes. The canal cross sectional area, on magnetic resonance imaging, improved from 85.78 mm2 (±28.45) to 150.5 mm2 (±38.66). The lumbar lordosis and segmental lordosis also improved significantly. The disc height was maintained in the postoperative period. All the radiographic improvements were maintained at 1-year follow-up. The MacNab criteria was excellent in 18 (56%), good in 11 (34%), and fair in 3 (9%) patients. None of the patients required conversion to open surgery or a revision surgery at follow-up. There was 1 patient with dural tear that was sealed with fibrin sealant patch endoscopically. There were 10 patients who had grade I stable listhesis preoperatively that did not progress at follow-up. No other complications like infection, hematoma formations etc. were observed in any patient.Full endoscopic outside-in decompression method is a safe and effective option for lumbar central canal stenosis with advantages of minimal invasive technique.

Incidental Durotomy During Endoscopic Stenosis Lumbar Decompression: Incidence, Classification, and Proposed Management Strategies.

OBJECTIVE: We sought to review the types of incidental durotomies (IDs) that occurred during the endoscopic stenosis lumbar decompression through interlaminar approach (ESLD) and discuss the management strategies according to our classification. METHODS: A retrospective evaluation was performed for patients with spinal stenosis who underwent ESLD. Out of 330 patients, 27 patients of ID were clinically evaluated preoperatively and postoperatively on the basis of a visual analog scale score, Oswestry Disability Index, and MacNab's criteria. ID patterns are classified according to the size, location, and involvement of neural elements. Intraoperative and postoperative surgical management was evaluated. RESULTS: Intraoperative incidence of ID was 8.2%. According to lumbar levels, 11 (40.7%) occurred at L3-4, 12 (44.4%) at L4-5, and 4 (14.8%) at L5-S1 ID cases. IDs were divided into 4 types: 29.6% are type 1, 70% are type 2, 7.4% are type 3, and 3.7% are type 4. Overall for mean and standard deviation preoperative, 1 week postoperative, 3 months, and final follow-up for visual analog scale are 7.6 ± 1.4, 3.3 ± 1.1, 2.6 ± 1.1, and 1.9 ± 1.3, and for Oswestry Disability Index are 74.5 ± 9.0, 32.3 ± 9.4, 27.3 ± 7.2, and 24.4 ± 6.5 after patch blocking dura repair of ID. CONCLUSIONS: ID is a more common surgical complication in ESLD compared with the transforaminal approach. The endoscopic patch blocking dura repair technique should be considered in type 1 to type 3A of dura tear with good prognosis and clinical outcome. Consideration is made for conversion to open repair in types 3B, 3C and 4 dura tears with fair to poor outcome.