# Long term clinical and MRI follow-up of 76 patients after synovial cyst resection via microscopic hemilaminectomy: a retrospective study

## TL;DR

This study examines the long-term outcomes of 76 patients who had synovial cysts removed using microscopic hemilaminectomy, finding a 13.2% reoperation rate and how preoperative spondylolisthesis affects postoperative results.

## Contribution

The study provides long-term clinical and MRI follow-up data on synovial cyst resection via microscopic hemilaminectomy, highlighting the impact of preoperative spondylolisthesis.

## Key findings

- Reoperation was needed in 13.2% of cases after a mean of 71.3 months.
- Preoperative spondylolisthesis was linked to higher postoperative disability and new instability.
- New asymptomatic instability or listhesis occurred in 49% and 28% of cases, respectively.

## Abstract

Synovial cysts can be treated by several non-instrumented surgical techniques, which are commonly grouped into non-homogenous cohorts. Few studies have analyzed surgical results of synovial cyst resection via microscopic hemilaminectomy with adequate imaging and long-term follow-up.

What is the long-term rate of reoperation, synovial cyst recurrence, new instability, listhesis progression, new synovial cysts in unoperated segments and postoperative patient function after synovial cyst resection via microscopic hemilaminectomy?

Seventy-six patients who underwent synovial cyst resection by microscopic hemilaminectomy were analyzed via a postoperative MRI, dynamic radiographs, clinical examination and Oswestry Disability Index (ODI). Dependent variables were rate of reoperation, new instability, listhesis progression, cyst recurrence, postoperative patient function and new stenosis/synovial cysts in unoperated segments. They were plotted against independent variables including age, intervertebral disc degeneration, indirect signs of instability and surgical invasiveness.

Reoperation was performed in 10 cases after a mean period of 71.3 months. Cyst recurrence occurred in 4 cases, new instability in 21 cases and listhesis progression in 37 cases. New synovial cysts and stenosis occurred in 6 and 9 cases respectively and 63 patients reported a postoperative ODI ≤40. Preoperative spondylolisthesis was associated with listhesis progression, new instability, higher postoperative ODI and new stenosis.

Treatment of synovial cysts by microscopic hemilaminectomy yields acceptable long-term results. Preoperative spondylolisthesis appears to affect postoperative ODI, instability and spondylolisthesis but not the reoperation rate or cyst recurrence. No other independent variable appeared to affect dependent variables.

•Reoperation rate of synovial cyst resection via hemilaminectomy is 13.2 %.•Preoperative spondylolisthesis is associated with higher postoperative ODI.•New asymptomatic instability or listhesis after surgery occurred in 49 % and 28 % of cases respectively.

Reoperation rate of synovial cyst resection via hemilaminectomy is 13.2 %.

Preoperative spondylolisthesis is associated with higher postoperative ODI.

New asymptomatic instability or listhesis after surgery occurred in 49 % and 28 % of cases respectively.