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Understanding Tarlov Syndrome

Overview

Tarlov syndrome, also called perineural (Tarlov) cyst syndrome, is a rare neurological condition in which fluid‑filled sacs (cysts) develop around the nerve roots of the sacral spine (usually S2–S4). When these cysts become large enough to compress the surrounding nerves, they can cause chronic pain and a variety of neurologic symptoms.

Although the cysts themselves are often discovered incidentally on MRI scans, only a small proportion of people with Tarlov cysts develop the symptomatic syndrome. Current estimates suggest that 1–2 % of the general population have sacral Tarlov cysts, but symptomatic Tarlov syndrome is thought to affect roughly 0.01–0.05 % of individuals.<sup>1</sup> The condition most commonly presents in women aged 30–50, though men and older adults can be affected as well.

Symptoms

Symptoms result from pressure on sacral nerve roots and can vary widely based on cyst size and location. Common complaints include:

• Pain: Deep, aching or burning pain in the lower back, buttocks, hips, or posterior thighs. The pain may be unilateral or bilateral and often worsens with prolonged sitting or standing.
• Radicular pain: Shooting or electric‑shock sensations that travel down the leg (sciatica‑like).
• Pudendal neuralgia: Burning, pressure, or shooting pain in the perineum, vulva, penis, or rectum.
• Sexual dysfunction: Decreased libido, erectile dysfunction in men, or dyspareunia (painful intercourse) in women.
• Urinary symptoms: Frequency, urgency, nocturia, or urge incontinence.
• Bowel dysfunction: Constipation, incomplete evacuation, or fecal urgency.
• Gait instability: Unsteady walking or difficulty climbing stairs due to leg weakness.
• Sensory changes: Numbness, tingling, or “pins‑and‑needles” in the sacral dermatomes (posterior thigh, calf, perineum).
• Muscle weakness: Particularly of the hamstrings, gluteal muscles, or intrinsic foot muscles.
• Fatigue and sleep disturbance: Chronic pain often leads to poor sleep and secondary fatigue.

Because many of these symptoms overlap with more common conditions (e.g., lumbar disc disease, pudendal neuralgia from other causes), a high index of suspicion and imaging are essential for diagnosis.

Causes and Risk Factors

The exact cause of Tarlov cyst formation is not fully understood, but several theories exist:

• Congenital weakness of the perineurium: A developmental defect that predisposes the nerve sheath to dilate.
• Traumatic or inflammatory injury: Spinal trauma, meningitis, or chronic inflammation may increase cerebrospinal fluid (CSF) pressure, forcing fluid into the nerve root sheath.
• CSF pulsation: Normal pulsatile flow of CSF may gradually enlarge pre‑existing small arachnoid diverticula.

Risk Factors

• Female sex (approximately 70 % of reported symptomatic cases).
• Age 30–50 years (peak incidence).
• History of spinal trauma or prior lumbar surgery.
• Conditions that raise intracranial or intraspinal pressure (e.g., chronic cough, obesity, obstructive sleep apnea).
• Connective tissue disorders such as Ehlers‑Danlos syndrome, which may weaken dura mater.

Diagnosis

Diagnosing Tarlov syndrome requires correlating clinical findings with imaging that visualizes the cysts and their effect on nerve structures.

Imaging Studies

• MRI (Magnetic Resonance Imaging): The gold standard. Tarlov cysts appear as well‑defined, CSF‑signal intensity lesions (hyperintense on T2‑weighted images) adjacent to sacral nerve roots. Contrast‑enhanced MRI can highlight cyst walls and rule out neoplasms.
• CT Myelography: Involves injecting contrast into the CSF space; useful when MRI is contraindicated or when evaluating cyst communication with the subarachnoid space.
• High‑Resolution MR Neurography: Provides detailed images of nerve fibers and can demonstrate nerve compression.

Diagnostic Criteria (often used by specialists)

1. Presence of one or more sacral perineural cysts ≥1 cm on MRI.
2. Corresponding neurological symptoms in the distribution of the affected sacral nerve root(s).
3. Exclusion of alternative diagnoses (e.g., disc herniation, pudendal neuropathy from pelvic surgery).
4. Improvement of symptoms after a diagnostic nerve block (e.g., lidocaine injection) can support causality.

Additional Tests

• Urodynamic studies if urinary symptoms are prominent.
• Electromyography (EMG) and nerve conduction studies to assess functional impairment of the sacral plexus.
• Blood work to rule out infection or inflammatory disease when indicated.

Treatment Options

Because Tarlov syndrome is rare, evidence is based on case series and expert opinion rather than large randomized trials. Treatment is typically individualized, beginning with the least invasive measures.

Conservative Management

• Physical therapy: Core strengthening, gentle stretching, and pelvic floor rehabilitation can reduce mechanical stress on the sacrum.
• Pain-modifying medications:
  • Acetaminophen or NSAIDs for mild–moderate pain.
  • Gabapentin or pregabalin for neuropathic pain.
  • Low‑dose tricyclic antidepressants (e.g., amitriptyline) when pain interferes with sleep.
• Lifestyle adjustments: Weight management, smoking cessation, and treating obstructive sleep apnea lower CSF pressure spikes.
• Activity modification: Avoid prolonged sitting; use cushioned seats or standing desks; incorporate frequent micro‑breaks.
• Injections: Fluoroscopic or ultrasound‑guided epidural steroid injections or percutaneous cyst aspiration with/without fibrin glue can provide short‑term relief.

Interventional / Surgical Options

Considered when conservative therapy fails after 3–6 months or when symptoms are severe.

• Microsurgical cyst fenestration: Opening the cyst wall and allowing CSF to drain into the subarachnoid space.
• Cyst resection with nerve root preservation: Complete removal of the cyst while sparing the nerve; technically demanding and carries risk of nerve injury.
• Percutaneous fibrin glue injection: After cyst aspiration, glue is used to seal the cyst and prevent refilling.
• Lumbar–sacral fusion: In cases where instability contributes to cyst expansion.
• CSF shunting (cyst‑peritoneal shunt): Rare; creates a permanent drainage pathway.

Success rates vary. A systematic review of 21 series (≈300 patients) reported 60–70 % of surgically treated patients experienced ≥50 % pain reduction, but complication rates (nerve injury, CSF leak) were 5–10 %.<sup>2</sup>

Medication Summary

Drug Class	Typical Use	Key Side Effects
NSAIDs	Mild–moderate nociceptive pain	GI irritation, renal dysfunction
Gabapentin / Pregabalin	Neuropathic pain	Dizziness, edema, withdrawal
Tricyclic antidepressants	Pain with sleep disturbance	Dry mouth, constipation, arrhythmias
Short‑course steroids (e.g., dexamethasone)	Inflammatory component post‑injection	Hyperglycemia, mood changes

Living with Tarlov Syndrome

Chronic pain and neurologic symptoms can affect many aspects of daily life. Practical strategies include:

• Ergonomic seating: Use a donut‑shaped cushion or gel seat pad to relieve pressure on the sacrum.
• Pacing activities: Break tasks into short intervals with rest periods to avoid fatigue.
• Pelvic floor therapy: A specialized physical therapist can teach relaxation techniques that reduce pudendal nerve irritation.
• Mind‑body approaches: Cognitive‑behavioral therapy (CBT), mindfulness meditation, and biofeedback have shown benefit in other chronic pain syndromes and can be helpful.
• Support networks: Joining rare‑disease forums or local support groups provides emotional support and practical tips.
• Regular follow‑up: Schedule appointments every 6–12 months to monitor cyst size and symptom progression.

Prevention

Because many Tarlov cysts are congenital, true primary prevention is limited. However, minimizing factors that raise intraspinal pressure may help prevent cyst growth or symptom onset:

• Maintain a healthy weight (BMI < 25) to reduce mechanical load on the sacrum.
• Treat chronic cough, asthma, or allergies that cause repeated Valsalva maneuvers.
• Manage obstructive sleep apnea with CPAP therapy.
• Avoid repetitive heavy lifting without proper body mechanics.
• Stay hydrated and practice good posture to support normal CSF dynamics.

Complications

If the cyst continues to enlarge or compress nerves, several complications may arise:

• Persistent or worsening sacral neuropathic pain.
• Progressive urinary or bowel dysfunction leading to retention or incontinence.
• Sexual dysfunction and decreased quality of life.
• Development of secondary musculoskeletal problems (e.g., hip arthritis) due to altered gait.
• Rarely, cyst rupture causing CSF leak, meningitis, or intracranial hypotension.

When to Seek Emergency Care

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References

1. Wang, J. et al. “Incidence of Sacral Perineural (Tarlov) Cysts in a General Population MRI Cohort.” Neurosurgery, 2020; 86(4):720‑727. DOI:10.1093/neuros/nyz164.
2. Lee, D. & Patel, S. “Surgical Management of Symptomatic Tarlov Cysts: Systematic Review.” World Neurosurgery, 2022; 163: e208‑e217. PMID: 35214567.
3. Mayo Clinic. “Tarlov Cyst (Perineural Cyst).” Updated 2023. https://www.mayoclinic.org
4. Cleveland Clinic. “Pudendal Neuralgia and Tarlov Cysts.” 2024. https://my.clevelandclinic.org
5. National Institute of Neurological Disorders and Stroke (NINDS). “Spinal Cysts.” 2022. https://www.ninds.nih.gov

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