Factors associated with recurrent back pain and cyst recurrence after surgical resection of one hundred ninety-five spinal synovial cysts: analysis of one hundred sixty-seven consecutive cases.

STUDY DESIGN:
Retrospective study.

OBJECTIVE:
Compare outcomes of different treatment methods for intraspinal synovial cysts.

SUMMARY OF BACKGROUND DATA:
Intraspinal synovial cysts are cited as an increasing cause of back pain and radiculopathy. To date, few studies have compared outcomes of differing treatment methods in patients with synovial cysts.

METHODS:
We retrospectively reviewed 167 consecutive patients undergoing surgical management of 195 symptomatic synovial cysts at a single institution over 19 years. The incidence of postoperative mechanical back pain, radiculopathy, and cyst recurrence was compared between patients undergoing unilateral hemilaminectomy (n = 51), bilateral laminectomy (n = 39), facetectomy with in situ fusion (n = 18), and facetectomy with instrumented fusion (n = 56).

RESULTS:
A total of 155 (97.5%) patients presented with radiculopathy, 132(82.5%) with mechanical back pain, 31 (20%) with neurogenic claudication, and 5 (3.2%) with bladder dysfunction. Most cysts occurred in the lumbar spine. After surgery, back and radicular pain improved in 91.6% and 91.9% patients, respectively. By a mean follow-up of 16 +/- 9 months, 36 (21.6%) patients developed recurrent back pain, 20 (11.8%) recurrent leg pain, and 5 (3%) recurrent synovial cysts. Patients undergoing laminectomy had a significantly increased cyst recurrence incidence compared to fusion groups via log-rank test (P = 0.042), and this risk was decreased to baseline with instrumented fusion on reoperation. Laminectomy was also associated with the highest increased risk of recurrent back pain in both log-rank test (P = 0.018) and proportional hazards regression (HR): 1.64 (1.00-3.45), P = 0.05. Instrumented fusion had the lowest risk for back pain recurrence.

CONCLUSION:
Hemilaminectomy or laminectomy remains one of the mainstay surgical treatments for symptomatic intraspinal synovial cysts. Our experience shows that the majority of patients undergoing decompression/excision of synovial cysts will have immediate improvement in back and leg pain. However, within 2 years, patients receiving hemilaminectomy or laminectomy alone have an increased incidence of back pain and cyst recurrence. Decompression with instrumented fusion appears to be associated with the lowest incidences of cyst recurrence or back pain.