Acceptable Fusion Rate of Single‐Level OLIF Using Pure Allograft Combined with Posterior Instrumentation through the Wiltse Approach: A 2‐Year Follow‐Up Study

Abstract

Objective Autogenic bone grafts have shown successful fusion rates in the treatment of degenerative lumbar disorders, but taking too many autogenic bones may result in donor site ischemia or infection. This study aimed to evaluate the outcomes of single‐level oblique lumbar interbody fusion (OLIF) using pure allograft combined with posterior pedicle screw instrumentation through the Wiltse approach. Methods A retrospective case analysis was performed on a series of consecutive patients who received a single‐level OLIF procedure combined with posterior pedicle screw instrumentation through the Wiltse approach between July 1, 2017, and December 31, 2019, in which pure allogenic bone graft was used and filled in the large window of the cage. The patients were followed up as scheduled at 1 day and 3, 6, 12, 24 months after operation. Clinical outcome was assessed by multiple questionnaires, including Oswestry disability index (ODI), Japanese Orthopaedic Association (JOA) score rating system, short form‐36 health survey (SF‐36), and visual analog scale (VAS) for low back pain. Radiographic outcome was evaluated by measuring the parameters such as disc height, lumbar lordosis, and segmental angle on the standard standing lateral radiographs, and the space angle of the fusion level on the dynamic views of the lateral radiographs. Subsidence of the cage and intervertebral fusion status were evaluated on both the radiographic and CT scan images. Results A total of 34 patients were finally included in this study. At 2‐year follow‐up, the VAS for low back pain, ODI, JOA, and SF‐36 scores all had significant improvement (p < 0.001). Substantial increase of anterior and posterior disc heights was observed (p < 0.001). Both lumbar lordosis and segmental angle became larger (p < 0.05). No visible change of the space angle of the fusion level was found on the dynamic views. The 1‐year fusion rate of 73.5% on CT scans proceeded to 82.4% at 2‐year follow‐up. The fusion rate was as high as 91.2% according to Bridwell interbody fusion grading system on radiographic images. The clinical outcomes in patients with incomplete fusion were just as good as those with complete fusion. The six patients with cage subsidence had higher ODI (p < 0.001) and lower JOA (p < 0.001) and SF‐36 PCS (p = 0.011) scores than those without cage subsidence. Conclusion The use of pure allograft in single‐level OLIF resulted in an acceptable fusion rate and satisfactory clinical effect at 2‐year follow‐up. Supplementation of posterior pedicle screw through the minimally invasive Wiltse approach ensured the favorable outcomes both clinically and radiographically.

Fusion Assessment of Oblique Lumbar Interbody Fusion Using Demineralized Bone Matrix: A 2-Year Prospective Study

“…The concept of fusion rate after lumbar interbody fusion is subject to interpretation in various studies; different studies have used nonidentical and heterogeneous criteria to assess bone fusion [ 11 , 16 , 21 , 26 - 28 ]. Many studies regarded patients without clear pseudoarthrosis as having successful fusion.…”

“…Autografts remain the gold standard material, displaying successful fusion rates in the treatment of degenerative lumbar disorders. However, procuring too many autogenic bone grafts may result in donor site morbidities, especially resulting in pain or infection [ 5 , 15 , 16 ]. The use of other alternative osteobiologics in spine surgery is believed to improve pain, fusion rates, and clinical outcomes [ 5 ].…”

“…In a recent systematic review and meta-analysis, the proportion of patients in the OLIF group who experienced pseudoarthrosis following the procedure was 6.1% (95% confidence interval [CI], 3.8–9.6) [ 19 ]. Xu et al [ 16 ] demonstrated an acceptable fusion rate of single-level OLIF using pure allograft combined with posterior instrumentation. In their 2-year follow-up study, the 1-year fusion rate of 73.5% on computed tomography (CT) scans proceeded to 82.4% at the 2-year follow-up period; the fusion rate was as high as 91.2%, according to the Bridwell interbody fusion grading system on radiographic images.…”

“…However, although several studies have reported successful fusion rates after OLIF using allografts or DBM instead of autografts [ 5 , 9 , 13 , 14 , 16 ], whether OLIF can achieve satisfactory solid fusion without the use of an autograft remains unclear. Accordingly, we designed this prospective observational study to investigate the real fusion rates after OLIF using DBM, which were evaluated using both dynamic radiography and CT at 12, 18, and 24 months after surgery.…”

Research Progress in Lumbar Interbody Fusion (LIF) Techniques and Bone Biomaterials

“…Studies have indicated a fusion rate of 84% or higher with OLIF surgery. [39]. The most frequent complications after OLIF surgery were endplate fracture/collapse (18.7%), transient lumbar muscle weakness and thigh numbness (13.5%), segmental artery injury (2.6%), surgical site infection (1.9%), and the need for reoperation (1.9%).…”