Sacral Foraminal (S2-3) Radiculopathy Syndrome (SFRS): Identification of a New PGAD/GPD Trigger in the Cauda Equina

Abstract

ABSTRACT Introduction Persistent Genital Arousal Disorder/Genito-Pelvic Dysesthesia (PGAD/GPD) is characterized by persistent, distressing genital arousal sensations for > 3 months and may include other genito-pelvic dysesthesia. PGAD/GPD is associated with biopsychosocial triggers, originating in any of 5 regions: end organ; pelvis/perineum; cauda equina; spinal cord; brain. In the cauda equina, surgically treatable PGAD/GPD triggers include Tarlov cyst and annular tear visualized on MRI. Sacral radiculopathy is confirmed by ruling out other triggers, combined with abnormal neurogenital tests and positive anesthetic lumbar/caudal epidural injections. We hypothesize that there are other treatable cauda equina lesions producing sacral radiculopathy despite a “normal” MRI. Objective We describe a new cauda equina PGAD/GPD trigger, associated with sacral radiculopathy, termed “sacral foraminal (S2-3) radiculopathy syndrome (SFRS).” Methods Women with PGAD/GPD > 3 months with sacral radiculopathy symptoms underwent a comprehensive biopsychosocial diagnostic evaluation including: sex therapy assessment; local anesthesia testing of suspected PGAD/GPD triggers in the end organ and pelvis/perineum; neurogenital testing: integrity of pudendal and sciatic nerves, bulbocavernosus reflex latency. PGAD/GPD patients with suspected SFRS had: no triggers in the end organ or pelvis/perineum; abnormal neurogenital test results; no evidence of surgically treatable Tarlov cyst or annular tear pathology on lumbosacral MRI; an anesthetic caudal epidural whenever possible, based on Tempest et al (2011). They reported on 4 women with GPD without lumbosacral MRI pathology who demonstrated temporary resolution of their dysesthesia with an anesthetic caudal epidural. Patients who met criteria for SFRS were offered non-significant risk treatment with low intensity sacral shockwave therapy (LiSWT). Results A total of 5 women (mean age 28 ± 6 years) who had a history of blunt trauma to the coccyx or sacrum from: a fall down icy stairs (n=1); childbirth (n=2); slipping/falling on wet concrete (n=1) and stretching while exercising (n=1) were identified. They were suspected of having sacral radiculopathy based on: i) history of dysesthesia symptoms involving genito-pelvic region (pelvic and pudendal nerve, n=5) and lower extremity region (sciatic nerve, n=3), ii) negative local anesthesia testing ruling out PGAD/GPD triggers in the end organ and/or pelvis/perineum, (n=5) iii) abnormal neurogenital tests showing a pattern consistent with cauda equina pathology, (n=5) and iv) clinically significant PGAD/GPD temporary symptom reduction with anesthetic caudal epidural, (n=3). As LiSWT is anti-inflammatory, 4 of the 5 women have undergone this therapy directed to the region overlying the sacral foramina, with very much (n=2) and much better (n=2) improvement of PGAD/GPD symptoms based on PGI-I after an average of 4 treatments. Conclusions The pelvic, pudendal and sciatic nerves enter at the S2 and S3 foramina where they converge to form the common S2-3 nerve roots. At this location, these nerve roots are only covered by thin peri- and epineurium, not thick, tough dura mater. We postulated that abrasion within the foramina from trauma to the sacrum locally irritated and inflamed these vulnerable nerve roots. Crucial supportive evidence is that clinically significant reduction of PGAD/GPD symptoms in 3 patients was observed in response to anesthetic injection directly into the caudal sacrum. Further research is needed. Disclosure No