Isadore Max Tarlov, MD, first described sacral cysts within the perineurial space occurring on the posterior roots or ganglia more than 80 years ago (1938).1 Although the clinical significance of these cysts was yet to be determined, it was hypothesized that an inflammatory process within the nerve roots followed by fluid uptake within the perineurial space could be the causative factor.1 Dr. Tarlov followed up his findings in 1948, concluding that these cyst can produce the “sciatic syndrome” and, therefore, sacral exploration should be considered in patients for whom known causes of sciatica had been surgically excluded.2 Clinical significance and treatment of Tarlov cysts, including if they are ever symptomatic, continues to be a controversial topic within the neurosurgical community.
Incidental Finding or Real Pathology
Today’s wide availability of neuroimaging has led to an increased prevalence of Tarlov cysts, 1.5-9%.3,4,6 Despite the growing numbers of Tarlov cysts identified, only 1% of patients experience symptoms that might be related, including:
- Low back pain
- Radicular pain
- Neurogenic claudication
- Bowel/bladder dysfunction
- Sexual dysfunction
- Coccydynia
- Leg weakness
- Lower extremity dysethesias 3,4,5
The severity and location(s) of symptoms may fluctuate as a result of maneuvers which increase intrathecal pressure.6 Symptomatic Tarlov cysts remain a diagnosis of exclusion, as it can mimic other etiologies and back and leg pain remain challenging to diagnose and treat. There are several misconceptions in regard to the significance of Tarlov cysts in pain as well as persistent beliefs that these cysts are irrelevant findings.5 However, one recent literature review (based exclusively on case series) suggests symptomatic Tarlov cysts should be considered in the differential diagnosis, because both percutaneous and surgical procedures have partial to complete resolution of symptoms in the majority of patients.7
Since its description in 1938, there has been no consensus for the appropriate management and follow up for symptomatic Tarlov cysts. Treatment options include:
- Pain management (specifically NSAIDS and steroids)
- Percutaneous cyst drainage, percutaneous fibrin glue injection
- Shunt placement (lumbo-peritoneal, cysto-subarachnoid, cysto-peritoneal)
- Microsurgical techniques
The literature is limited and based on retrospective case reports/series with small samples sizes; yet, treatment modalities are recommended as methods of choice.8 Studies comparing medical, interventional and surgical treatments are sparse and debatable.
Increasing Evidence against Surgery
A meta-analysis compared surgical versus non-surgical management of symptomatic Tarlov cysts in 2019.9 The review compared 38 studies (32 surgical, six non-surgical) that included 750 patients. Symptomatic improvement was similar in both groups at 83.5%. Postoperative complications were significantly higher in the surgical group. Serious complications included 9% CSF leak, 17% transient sciatica, 11% sexual dysfunction, 5% wound infections and 18% other (venous bleeding, transient intracranial hypotension, seroma, cerebellar hemorrhage and prostatitis). Within the non-surgical group, 3% CSF leak, 8% transient sciatica and 3% other (aseptic meningitis, allergic reaction to sealant) were noted. Recurrence of symptoms were similar in both groups 21% surgical and 20% non-surgical. A higher rate of cyst recurrence was identified in the non-surgical group at 20% (8% in surgical group). Regarding cyst recurrence, the surgical group had better outcomes. However, there was no difference in postoperative symptomatic improvement or the recurrence of symptoms at long-term follow up.9
Symptomatic Management and Consideration of Percutaneous Interventions
More than 50 years after their description, neurosurgery understands little about Tarlov cysts and virtually nothing about the ideal treatment. Through the years, the pendulum has swung from aggressive surgical treatment and back again. Even the diagnosis of symptomatic Tarlov cysts remains controversial and should always be a diagnosis of exclusion. Initial treatment would include NSAIDs and possibly steroids. Interventional procedures, such as percutaneous drainage and percutaneous fibrin injections can be considered next, if medical therapy fails. Although cyst recurrence is a possibility, interventional management is as efficacious in resolution of symptoms long-term without the significance in short-term perioperative complications seen in surgically treated patient. Although some facilities aggressively treat this disease surgically, it should occur infrequently and after all medical and interventional measures have failed. Further studies are required to develop a progressive treatment paradigm as seen in other neurosurgical pathologies. Additionally, cost effectiveness should also be analyzed in further studies, as this seems to be favorable in the non-surgical group (decreased hospital lengths of stay and complications). Ultimately, clinicians must determine if benefits outweigh the risks for aggressive treatment, because it can lead to significant morbidity while maintaining a significant risk for recurrence of symptoms.
References
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6. Feigenbaum, F., & Henderson, F. (2012). Tarlov cysts. Benzels spine surgery: Techniques, complication avoidance, and management. Philadelphia, PA: Elsevier.
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