True synovial cysts of the lumbar spine: an epiphenomenon of instability of the functional spine unit?

Spontaneous Resolution of Symptomatic Synovial Cysts of the Lumbar Spine: A Comprehensive Review with Two Illustrative Cases

Although lumbar synovial cysts (LSCs) are frequently described in the literature, they are a relatively uncommon cause of low back and radicular leg pain. Furthermore, their spontaneous resolution is an even rarer event. The standard treatment of the lumbar synovial cyst is surgical excision. Spontaneous resolution in the literature is a sporadic event. In our experience, we have had two cases where the lumbar synovial cyst disappeared spontaneously. To date, only nine cases of spontaneous resolution of synovial cysts have been documented in the literature. In this discussion, we highlight a pathology that typically suggests surgical intervention, yet conservative treatment can be a viable alternative. We present two cases of large synovial cysts that were initially scheduled for surgery but ultimately resolved spontaneously without any treatment. While the spontaneous resolution of lumbar synovial cysts is extremely rare, conservative strategies are an option that should not be overlooked. Our cases contribute to the growing body of evidence on the spontaneous regression of symptomatic LSC, potentially enhancing the understanding of the disease's natural progression in the future.

Acute development of spinal lumbar synovial facet cyst within 1 week after lumbar decompression: illustrative case

BACKGROUND

Synovial facet cysts can sometimes develop in patients with lumbar spinal stenosis after decompressive laminectomy. The etiology of spinal lumbar synovial cysts is still unclear, but their formation is associated with underlying spinal instability, facet joint arthropathy, and degenerative spondylolisthesis.

OBSERVATIONS

A 61-year-old-male patient presented with neurogenic claudication due to lumbar spinal stenosis. Radiographic studies showed grade I spondylolisthesis and radiological predictors of delayed spinal instability. He underwent lumbar decompression and shortly thereafter developed spinal instability and recurrent symptoms, with formation of a new spinal lumbar synovial facet cyst. He required revisional decompression, cyst excision, and posterolateral spinal fusion for definitive treatment.

LESSONS

The literature reports postoperative spinal instability in up to one-third of patients with lumbar spinal stenosis and stable degenerative spondylolisthesis who undergo decompressive laminectomy. Close radiographic monitoring and early advanced imaging may be prudent in this patient population if they develop new postoperative neurological symptoms and show radiographic predictors of instability on preoperative imaging. Posterolateral spinal fusion with instrumentation should be considered in addition to lumbar decompression in this select group of patients who demonstrate radiographic predictors of delayed spinal instability if they are medically capable of tolerating a spinal fusion procedure.

Outcomes and complications following minimally invasive excision of synovial cysts of the lumbar spine: A systematic review and meta-analysis

OBJECTIVE

Lumbar synovial cysts (LSC) are one of the manifestations of spinal degenerative cascade. Spinal stenosis or presence of instability in these patients can lead to various symptoms and surgery is indicated following failure of non-operative management for symptomatic synovial cysts. Surgery when performed consists of either decompression with resection of cyst with our without fusion. The efficacy and complications of minimally invasive techniques using tubular retractors (microscopic or endoscopic) in comparison to traditional open techniques remain to be studied.

METHODS

A comprehensive search of different databases was performed to retrieve studies describing the use of minimal invasive techniques using tubular retractors (both microscopic and endoscopic) in patients with LSC. Meta-analysis with subgroup analysis and metaregression was done.

RESULTS

Twenty articles were selected for the systematic review and meta-analysis with total of 388 patients. Eighty-six percent of patients (95% Confidence Interval (CI): 80-90%) had favorable outcome as per Macnab's criteria (excellent and good outcome) with the pooled standard mean difference between preoperative and postoperative Oswestry Disability Index (ODI) being -4.44 (95% CI -8.78 to -0.10, p-value=0.0474, I² 82%). The pooled percentage change in visual analogue scale (VAS) after surgery was 76.5% (95% CI 66.9-84%, I² 82%). The pooled proportion of incidental durotomies, cyst recurrence and patients requiring operation being 8% (95% CI 5-11%, I² 0%), 4% (95% CI 2-7%, I² 0%,) and 5% (95% CI 3-9%) respectively. Studies were homogeneous with an I² value of 0%. Subgroup analysis revealed no significant difference in the outcome rates or complication rates between the microscopic and endoscopic subgroups.

CONCLUSION

Minimally invasive techniques for the resection of LSC is a safe and effective alternative to traditional surgical approaches with no difference between the microscopic and endoscopic approaches.

Lumbar synovial cysts: presentation of a series of 10 cases and literature review

INTRODUCTION

Although they are freqqently described in the literature, lumbar synovial cysts are a relative uncommon cause of low back and radicular leg pain.

OBJECTIVE

To evaluate the treatment and surgical outcomes of the lumbar synovial cysts operated on in our hospital during a 5 year period.

MATERIAL AND METHODS

A retrospective study was conducted on patients surgically treated in our department from August 2009 to September 2014, using a visual analogue scale for the clinical follow-up in the first year after surgery.

RESULTS

After the surgical treatment (surgical removal of the synovial cyst with or without instrumented arthrodesis with transpedicular screws) of 10 patients (5 female and 5 male) with a mean age of 70.2 years (range 50-80), the clinical outcome was satisfactory in 80% of the patients, with the resolving of their symptoms.

CONCLUSIONS

Lumbar synovial cysts have to be considered in the differential diagnosis in patients with low back and radicular leg pain. The majority of the patients are in their sixties and have lumbar degenerative spondylopathy. Nowadays, surgical resection of the lumbar synovial cysts and spinal fusion are the recommended treatment, because it is thought that the increased movement of the spine is one to the causes of the cyst formation. More studies are still needed, hence the relevance of this article.