Observation on the clinical efficacy of"sandwich"bone graft encapsulation technique using gelatin sponge-rhBMP-2 composite bioactive material in oblique lumbar interbody fusion

HAN Xu; ZENG Jiancheng; XIE Tianhang; WANG Xiandi; LUO Chuan; HU Xiao; PENG Xingrui

doi:10.3969/j.issn.1674-3806.2026.02.06

Abstract：Objective To observe the safety and effectiveness of"sandwich"bone graft encapsulation technique using gelatin sponge-recombinant human bone morphogenetic protein-2(rhBMP-2)composite bioactive material in preventing graft-related leakage and promoting osseous fusion in oblique lumbar interbody fusion(OLIF).Methods A retrospective analysis was performed on the clinical data of 834 patients with lumbar degenerative diseases who underwent L4-5 segment OLIF in West China Hospital,Sichuan University from November 2017 to July 2023.The patients included 380 males(45.6％)and 454 females(54.4％),aged 23-89(63.3±11.8)years.The operation time,intraoperative blood loss and hospital stay of the patients were recorded.The clinical efficacy was evaluated by using Visual Analogue Scale(VAS)scores and Oswestry Disability Index(ODI).Sagittal lumbar three-dimensional computed tomography(3D-CT)was used to measure the disc height(DH)before the operation and 1 day,12 months and 24 months after the operation.Cage subsidence was graded by using Marchi classification system,and interbody fusion status was assessed according to Bridwell grading criteria.Results All the patients were operated successfully without any complications such as graft migration,graft leakage or graft-related neurological compression.The average operation time was(87.2±11.8)min.The average intraoperative blood loss was(33.3±7.4)mL,and the average hospital stay was(5.3±1.5)days.The postoperative follow-up duration ranged from 24 to 90 months,with a median follow-up duration of 28(24,43)months.Compared with those before the operation,the VAS scores for assessing low back pain and leg pain as well as the ODI of the patients at 3 months,12 months and 24 months after the operation continued to improve significantly,and the differences were statistically significant(P＜0.05).Postoperative imaging measurement demonstrated a restoration of DH in the operated lumber vertebra segments at 1 day after the operation,with favorable maintenance at 12 months after the operation.At 24 months after the operation,the imaging fusion rate reached 93.8％(Bridwell grades Ⅰ-Ⅱ),and the incidence of cage subsidence was 22.9％.Conclusion The application of"sandwich"bone graft encapsulation technique using gelatin sponge-rhBMP-2 composite bioactive material in OLIF shows good safety and feasibility.It has the advantages of simple operation,short operation time and low complication rate.While ensuring the efficiency of minimally invasive surgery,it achieves good clinical efficacy.