A feasibility study examining the utility of sacral dermatomal evoked potentials in assessing urogenital dysfunction

Tarlov cysts are cerebrospinal fluid-filled sacs that form in multiple numbers at the location of the dorsal root ganglia in the sacral spinal cord region. Tarlov cysts have been known for over seventy years and are often considered benign findings in MRI reports. A group of predominantly female patients suffer from one or more symptoms, such as lower back pain, lower limb pain, sensory disturbance in the perineum, urinary incontinence, constipation, and sexual dysfunction, for no apparent reasons. All these patients have one common feature – Tarlov cysts in their sacral spinal segment. Most of the traditional diagnostic tests would not be helpful in this group. Since all patients with Tarlov cysts do not suffer from these symptoms, traditionally, their presence is often ignored, and patients with urogenital symptoms are investigated for urological, gynaecological, gastroenterological, or spinal causes. Many tests cause more delays in treatment and create economic and psychological burdens on these patients.

The aims of this study are:

1. To develop and establish sacral dermatomal evoked potential (dSEPs) tests that can reliably assess sacral root function.
2. Validate these tests in known spinal cord injury patients.
3. To provide objective evidence for sacral root dysfunction in Tarlov cyst patients.

This study has shown a new method to record reliable and reproducible sacral dSEPs in healthy individuals. This study revealed the usefulness of dSEPs in assessing sacral root injuries and predicting the severity of the injuries. Ultimately, the study has shown that a large number of patients (65%) with symptomatic Tarlov cysts suffer from the S4 sacral root dysfunction. This study paves the way for Tarlov cyst patients to have better diagnoses and treatments.