Clinical and Radiological Outcomes after Reducing Adult Lytic High-Grade Spondylolisthesis Using a Hybrid Technique: Combination of Percutaneous Pedicle Screws with Midline Microscopic Transforaminal Decompression.

Study design: Retrospective study.

Purpose: To analyze the results and effectiveness of percutaneous screws (PS) with midline microscopic transforaminal decompression (MTFD) technique in reducing adult stiff lytic high-grade spondylolisthesis (HGSL) and compare it with the conventional technique.

Overview of literature: Pedicle screw cannulation and segmental kyphosis negotiation are surgical challenges in HGSL. Open reduction is the preferred approach. PS have the advantage of optimized trajectory and minimized soft tissue exposure. The role of minimally invasive surgery in HGSL remains unknown. We propose a hybrid technique combining PS with MTFD for lytic HGSL.

Methods: This study included 25 patients with adult lytic HGSL (Meyerding grade III and IV) operated using a hybrid technique from 2012 to 2015. Data were compared with retrospective data on conventional open reduction (n=23) operated from 2000 to 2015. The minimum follow-up was 5 years. Clinical outcomes were assessed using the Visual Analog Scale (VAS) score and modified Oswestry Disability Index (m-ODI). The spinopelvic and perioperative parameters were recorded. The inter-body fusion and adjacent segment degeneration (ASD) were assessed on radiographs at the final follow-up.

Results: The average age in the MTFD and open groups was 45.84±12.70 years (nine males and 16 females) and 49.26±13.33 years (eight males and 15 females), respectively. Further, 22 and three patients in the MTFD group and 19 and four in the open group had grade III and IV listhesis, respectively. The MTFD group demonstrated less operative time, blood loss, and hospital stays than the open group. Significant improvements were observed in VAS and m-ODI in subsequent follow-ups in both groups. The MTFD group fared better at 3 months but outcomes were comparable at the final follow-up. Both techniques were equally effective in restoring spinopelvic parameters. The incidence of ASD is comparable.

Conclusions: The technique was proven effective in reducing HGSL. The long-term clinical and radiological outcomes were favorable and comparable with the conventional approach.