Multilevel instrumented posterolateral lumbar spine fusion with an allogeneic cellular bone graft

Abstract

Background: Low back pain (LBP) is the leading cause of absence from work, disability, and impaired quality of life. Fusion surgery may be indicated when non-operative treatments have failed to provide relief. Surgery may include the use of fusion-enhancing implants, such as cellular bone allografts (CBAs). The purpose of this retrospective study was to evaluate efficacy and safety of one CBA (V-CBA) in patients who underwent instrumented posterolateral fusion (IPLF).

Methods: Retrospective data were collected from 150 consecutive patients who had undergone IPLF surgery between January 1, 2015, and March 31, 2018, in which V-CBA was used. All surgeries were performed by one surgeon. V-CBA was mixed with local autograft bone. Patient diagnoses included degenerative disc disease, spondylosis, spondylolisthesis, or spondylolysis with or without stenosis. Standing anteroposterior (AP) and lateral images were collected prior to surgery and again at the terminal visit, which took place between 6 and 33 months post-operatively. De-identified images were assessed radiologically. Adverse events were documented. The primary composite endpoint of fusion status was dependent upon two main criteria: bridging bone per the Lenke scale (classified as "A" definitely solid or "B" possibly solid) and posterior hardware status (intact). Lenke scale C or D were categorized as pseudarthrosis.

Results: Eighty-seven male and 63 female patients (613 levels total) underwent IPLF in which V-CBA was implanted. An average of 4.1 levels was treated, with 59.3% of patients having undergone treatment for more than 3 levels. Twenty-nine percent of patients had diabetes. Fifty-two percent of patients had previously used nicotine products, and 12% were current smokers. Sixteen serious adverse events were recorded and included lumbar seroma, cerebrospinal fluid leak, wound dehiscence, pneumonia, urinary tract infection, and myocardial infarction. Successful fusion (Lenke scale "A" or "B") was recorded in 148 out of 150 patients (98.7%), or 608 out of 613 levels. The total pseudarthrosis rate was 0.8%.

Conclusions: The use of V-CBA combined with local autograft in multilevel IPLF resulted in successful fusions in 98.7% of patients. These results are particularly robust given the complex nature of many of these cases: 89 patients had 4 or more surgical levels, and many patients had multiple comorbidities.

Level of evidence: IV.

Keywords: Allograft; Bone regeneration; Cellular bone allograft; Low back pain; Multilevel; Posterolateral fusion.

Fig. 1

Fusion status as terminal visit. Terminal visits were divided into post-operative time periods: at 6 months, > 6–12 months, and > 12 months. The X-axis describes the number of patients at each surgical level in the respective terminal visit time period. The Y-axis describes the percent of patients at each surgical level for each terminal time period that had Lenke fusion A, B, C, or D. a For the terminal visits at 6 months, 96% of patients were considered fused (80 Lenke A and 16% Lenke B), while 4% were not fused (Lenke C). b For patients who had post-operative terminal visits > 6–12 months, 100% were considered fused (76% Lenke A and 24% Lenke B). c For the patients whose terminal visit happened after 12 months post-operatively, 98% were considered fused (83% Lenke A, 15% Lenke B, 2% Lenke D)

Fig. 2

Representative radiographs and combined fusion for all patients. a 69-year-old male, former smoker with a body mass index of 26 presented with back pain and left lower extremity radicular pain. Conservative treatment included physical therapy, stretching, epidural spinal injections, and NSAIDs. b Seven months after L4-S1 decompression and fusion were performed, the patient was fused (Lenke A). c Combined fusion graph (Lenke A + Lenke B) shows that 148 of 150 patients (98.7%) were considered fused: 119 patients Lenke A and 29 Lenke B

Fig. 3

The relationship between the number of surgical levels, operating room (OR) time, and blood loss. As the number of surgical levels increases, the amount of time spent in the OR (minutes) and blood loss (cc) generally increased (mean/SD)