UNASSIGNED: High-grade spondylolisthesis is defined as cases with more than 50% displacement and spondylolisthesis with Meyerding grade III and higher. The surgical management of high-grade spondylolisthesis is highly controversial. Many surgical methods have been reported such as posterior in situ fusion, instrumented posterior fusion with or without reduction, combined anterior and posterior procedures, spondylectomy with reduction of L4 to the sacrum (for spondyloptosis), and posterior interbody fusion with trans-sacral fixation. The literature has recently mentioned minimally invasive transforaminal lumbar interbody fusion for high-grade spondylolisthesis. This study aimed to review the recent literature that describes the surgical outcomes associated with various surgical techniques used for high-grade spondylolisthesis.
UNASSIGNED: Recent articles were searched on search engines such as PubMed and Google Scholar using keywords such as \"high-grade spondylolisthesis,\" \"surgical techniques,\" and \"complications.\"
UNASSIGNED: The surgical management of high-grade spondylolisthesis is an area of significant controversy. The literature is replete with regards to the need for reduction, decompression, levels of fusion, the nature of instrumentation, surgical approaches including open, minimally invasive, and \"mini-open\" procedures, and various techniques for reducing the slip and fusion strategy. The three basic options of high-grade spondylolisthesis include in-situ fusion, partial reduction and fusion, and complete reduction.
UNASSIGNED: Various techniques have been described for high-grade spondylolisthesis. Spine deformity study group classification gives guidelines about balanced and unbalanced pelvis and advises reduction and fusion in case of unbalanced pelvis for correction of biomechanical and global sagittal alignment. Each of the surgical techniques has its advantages and disadvantages. However, individual authors\' experience, skill levels, and anatomic reduction with fusion techniques have yielded encouraging results.

OBJECTIVE: To compare the clinical effectiveness of reduction and fusion with in situ fusion in the management of patients with degenerative lumbar spondylolisthesis (DLS).
METHODS: The systematic review was conducted following the PRISMA guidelines. Relevant studies were identified from PubMed, Embase, Scopus, Cochrane Library, ClinicalTrials.gov, and Google Scholar. The inclusion criteria were: (1) comparative studies of reduction and fusion versus in situ fusion for DLS patients, (2) outcomes reported as VAS/NRS, ODI, JOA score, operating time, blood loss, complication rate, fusion rate, or reoperation rate, (3) randomized controlled trials and observational studies published in English from the inception of the databases to January 2023. The exclusion criteria included: (1) reviews, case series, case reports, letters, and conference reports, (2) in vitro biomechanical studies and computational modeling studies, (3) no report on study outcomes. The risk of bias 2 (RoB2) tool and the Newcastle-Ottawa scale was conducted to assess the risk of bias of RCTs and observational studies, respectively.
RESULTS: Five studies with a total of 704 patients were included (375 reduction and fusion, 329 in situ fusion). Operating time was significantly longer in the reduction and fusion group compared to in situ fusion group (weighted mean difference 7.20; 95% confidence interval 0.19, 14.21; P = 0.04). No additional significant intergroup differences were noted in terms of other outcomes analyzed.
CONCLUSIONS: While the reduction and fusion group demonstrated a statistically longer operating time compared to the in situ fusion group, the clinical significance of this difference was minimal. The findings suggest no substantial superiority of lumbar fusion with reduction over without reduction for the management of DLS.

OBJECTIVE: The aim of the present study is to evaluate the results of our all posterior-one stage surgical technique for the reduction and fusion of high-grade high-dysplastic spondylolisthesis.
METHODS: Patients over 11 years old with high-grade spondylolisthesis treated by reduction and circumferential fusion with a posterior-only approach were reviewed. Data about operative time, blood loss, length of stay, intra- and postoperative complications were collected. Meyerding grade (M), lumbar lordosis (LL), thoracic kyphosis (TK), pelvic incidence (PI), pelvic tilt (PT), lumbosacral angle (LSA), slip angle (SLIP), lumbar index (LI) and severity index were measured on preoperative and last follow-up. Sagittal vertical axis (SVA) was used to assess sagittal balance.
RESULTS: Of the 14 included patients, L5-S1 arthrodesis was performed in 12 cases, and L4-S1 was performed in 2 cases. Average surgical time was 275 ± 65 min; average blood loss was 635 ± 375 mL. Average length of stay of was 3.9 ± 1.5 days. The SLIP angle improves from 33.8° ± 7.3° to 6.4° ± 2.5°, (p = 0.002); the lumbosacral angle improves from 68.8° ± 18.6° to 100.7° ± 13.2°, (p = 0.01); and the SVA decreased from 49.4 ± 22.1 mm to 34.4 ± 8.6 mm (p = 0.02). No significant changes were observed in PI, PT and SS. Thoracic kyphosis (TK) and lumbar lordosis (LL) did not change significantly. At last follow-up, no patient had surgical site infection or mechanical complications; no pseudoarthrosis was observed. No revision surgery was performed.
CONCLUSIONS: Although technically demanding, reduction and fusion with one stage all posterior approach prove to be a safe and effective.