Vivian N. Cao, MS
OMS-IV
Touro College of Osteopathic Medicine - Harlem
Colonia, New Jersey, United States
Jeremy Benhamroun-Zbili, DO
Assistant Professor
Northwell Lenox Hill Hospital, Zucker School of Medicine at Hofstra University
New York, New York, United States
A 67-year-old female with sciatic neuritis, lumbar herniated disk, and L5-S1 lumbar radiculopathy presented to the clinic with ongoing right lower back pain for 6 weeks without any specific injury or inciting event. Patient reported throbbing, achy pain radiating to right buttock and posterior/ lateral right leg that worsened with sitting, standing, and walking. Physical exam was notable for positive right piriformis sign, straight leg raise, and Gaenslen test. Lumbar MRI revealed extensive perineural cysts throughout the parasacral canal and L5/S1 right paracentral / foraminal disc protrusion. Pelvic MRI described the presence of a mass posterior to the femur and the pelvis.
The patient’s pain improved nominally with Medrol dose pack, oxycodone, or gabapentin. There was moderate improvement in symptoms with L5-S1 transforaminal epidural steroid injection, right piriformis injection, and physical therapy. Aspiration of a ganglion cyst on the sciatic nerve provided the greatest relief for the patient’s pain.
Discussions: Perineural cysts, also known as Tarlov cysts, are CSF filled sacs that are typically found at the sacral level around the dorsal root ganglion and have an unclear pathogenesis. They are rare but are more common in females. Historically considered to be incidental findings, perineural cysts have in several cases, been identified as contributing neurogenic pain. Treatment ranges from conservative to surgical interventions, with the latter being reserved for symptomatic cases refractory to conservative management
Conclusions:
Low back pain is one of the most common complaints seen in clinic and is usually multifactorial. This case demonstrates complex radicular pain due to multiple etiologies. When evaluating lumbar radiculopathy, it is important to consider other compressive etiologies of nerve entrapment such as perineural cysts or peripheral compressive syndromes.
