Minimally Invasive Posterior Tubular Microsurgical Approach for the Management of Symptomatic Synovial Cysts of the Lumbar and Cervical Spine

Background: Synovial cysts are commonly associated with instability. Whether to fuse patients is a matter of controversy. Simple resection may offer favorable clinical outcomes but may come at the expense of recurrence rate. We describe our experience with the minimally invasive management of these lesions using microsurgical dissection through a tubular retractor system. Materials: A retrospective cohort study of symptomatic patients with synovial cysts treated by a minimally invasive tubular approach from 2001 to 2018 was performed. We evaluated variables such as preexisting spinal pathology, previous surgery, radiological findings, comorbidities, and secondary surgery requiring fusion. We used the visual analog scale (VAS), the Oswestry disability index (ODI), and the Macnab scale for clinical evaluation. Results: There were 35 patients with a mean age of 63 years. The mean duration of symptoms before surgery was 195 weeks. Axial pain was present in 77.1% of cases; radiculopathy was the main symptom in 94.3% of cases. The most frequent site was L4-L5 (62.8%). Presenting comorbidities were lumbar stenosis (28.6% of patients), spondylolisthesis (8.6%), and facet hypertrophy (31.4%). Mean surgical time was 143 minutes (range, 55-360 minutes). The mean hospital stay was 2 days, ranging from 1 to 5 days. No complications were encountered as a consequence of the surgical procedure. All patients showed neurophysiological improvement after surgical intervention. A total of 34 patients (97.14%) showed clinical improvement at the end of follow-up, averaging 17 months and ranging from 1 to 60 months, 28 patients (80%) had good to excellent Macnab outcomes, 6 patients (17.14%) were rated as fair, and 1 (2.86%) patient had a poor Macnab outcome. Radicular VAS significantly changed (P < .05) from a preoperative mean of 8.23 +/- 1.24 to a postoperative mean of 2.23 +/- 1.94. ODI significantly decreased (P < .05) from a preoperative of mean of 41.02 +/- 12.56 to a postoperative of mean of 11.82 +/- 10.56. We performed fusion at initial surgery in 37.1% of cases; however, 3 more patients required secondary fusion at follow-up. Conclusion: Our series corroborates the prior literature with a low incidence of synovial cysts in the cervical spine and none in the thoracic spine. The present work shows the efficacy of minimally invasive surgery in the treatment of these lesions. Synovial cysts were associated with instability, ultimately requiring fusion in the majority of patients. The authors' study includes a large patient series with minimally invasive microsurgical decompression performed through a tubular retractor to date.