Effectiveness of biportal endoscopic lumbar interbody fusion using the multi-layer bone grafting technique: a retrospective study from Vietnam.

Study design: A retrospective cohort study.

Purpose: This study aimed to describe the surgical technique of biportal endoscopic (BE) lumbar interbody fusion (LIF) using a multi-layer bone grafting method and to investigate its clinical effectiveness in treating patients with grade I or II lumbar spondylolisthesis (LS).

Overview of literature: Previous studies have described BE-LIF; however, these reports predominantly originate from advanced centers in developed countries, using sophisticated implants such as dual transforaminal LIF (TLIF), oblique LIF, or titanium cages. In contrast, the described method utilizes hydroxyapatite (HA) bone grafts and autologous bone obtained from the preserved inferior articular process (IAP), combined with a single conventional TLIF cage, which provides a cost-effective alternative.

Methods: This study included 41 patients with single-level grades 1 or 2 LS from February 2023 to February 2024. Clinical outcomes were assessed using the Visual Analog Scale (VAS) for back and leg pain and the Oswestry Disability Index (ODI). Bridwell fusion grades were evaluated via lumbar spine computed tomography performed 6 months postoperatively.

Results: Over a mean follow-up period of 10.6 months (range, 7-18 months), significant improvements were observed in VAS scores for low back pain (from 7.8±0.8 to 2.1±1.4) and leg pain (from 8.1±1.3 to 1.9±1.5) as well as ODI scores (from 50.4±15.4 to 14.8±10.5). The cohort consisted of patients with grades 1 (73.2%) and 2 LS (26.8%) at L4-L5 (58.6%), L5-S1 (34.1%), and L3-L4 (7.3%) levels. The mean operation time was 182.8±36.4 minutes, with a mean intraoperative blood loss of 190.5±81.3 mL and a mean hospital stay of 7.2±3.6 days. Successful fusion (Bridwell grades I/II) was achieved in 82.9% of the cases, with a 4.9% incidence of cage subsidence. Minor complications included durotomies in two patients (4.9%), whereas no major complications, such as nerve root injury, hardware-related issues, or postoperative infections, were reported.

Conclusions: The described BE-LIF technique, using HA bone grafts, which are an autologous bone from the preserved IAP, and a TLIF cage, is a viable, safe, and effective option for treating low-grade LS. This approach achieves favorable clinical outcomes and high fusion rates, which provides a cost-effective alternative to advanced surgical implants.