Introduction: Degenerative spondylolisthesis is one of the most common pathologies spine surgeons treat. While a number of potential factors have been identified, there is no current consensus on which variables most impact the decision to fuse vs. decompress alone in this population. The aim of this study was to identify radiographic and clinical factors leading to the decision to fuse segments for one level spondylolisthesis.

Methods: A survey consisting of questions pertaining to decision factors leading to fusion or decompression alone in the setting of degenerative lumbar spondylolisthesis was administered to the Lumbar Spine Research Society and Society of Minimally Invasive Spine Surgery. Radiographic parameters included grade of spondylolisthesis, instability, facet orientation > 60 degrees, facet diastasis, laterolisthesis or scoliosis, synovial cysts, vacuum disc, vertical disc space, preserved disc height, concomitant herniated nucleus pulposus, and symptomatic foraminal stenosis. Clinical factors included age > 70 years, activity level, patient sex, body mass index >35, osteoporosis, primary complaint of low back pain, primary complaint of neurogenic claudication, smoking, and anxiety/depression.  Following completion, surveys were collected and analyzed using SPSS version 27. The primary analysis was limited to completed surveys. Baseline characteristics were summarized. Clinical and radiographic parameters were ranked and compared. The most important, top three most important, and top five most important parameters were ordered given each parameter ranking. Using Chi-Squared, Fisher’s exact test, or two-sample t-test as appropriate.

Results: Of 561 surveys, 381 (67.9%) were returned completed. Respondents mean years in practice was 17.8 ± 9.4 years and 296 (77.7%) had undergone a formal spine fellowship. The majority of respondents were from the US (45.9%) followed by Europe (24.1%), and Asia/Pacific (17.1%). The practice setting included academics (32.5%), private practice (31.0%), hospital employed (17.1%), or a combination (19.4%). The mean number of degenerative spondylolisthesis cases performed per year for each surgeon was 53.8 ± 46.7 cases with 49.9% of the cohort performing these cases utilizing minimally invasive techniques. With regards to fusion vs. decompression, 19.9% fuse all cases, 39.1% fuse > 75%, 17.8% fuse 50-75%, and 23.2% fuse <25%. Instability (93.2%), spondylolisthesis grade (59.8%), and laterolisthesis (37.3%) were the most common radiographic factors impacting the decision to fuse (Table 1), whereas mechanical low back pain (83.2%), activity level (58.3%), and neurogenic claudication (42.8%) were the top clinical parameters (Table 2).

Conclusion: There is little consensus on the treatment of degenerative spondylolisthesis, with society members showing substantial variation in treatment patterns. The most common radiographic parameters impacting treatment are instability, spondylolisthesis grade, and laterolisthesis while mechanical low back pain, activity level, and neurogenic claudication are the most common clinical parameters.