Introduction

Schwannomas stand out as the most prevalent benign tumors affecting the spinal nerve sheath [1,2]. The annual incidence in the United States is approximately 0.24 per 100,000 people [3], with patients typically manifesting symptoms in their fourth to fifth decade of life [4,5]. Recent research indicates a higher occurrence rate in males, while lower incidence rates are associated with Black and American Indian/Alaska Native races [3]. Ponti et al reported a significant occurrence of about 48% in the lumbosacral region [5]. Schwannomas are characteristically solitary, well-defined, and encapsulated tumors [6]. Histologically, they are made up of mixed bundles of long spindle-shaped Schwann cells (referred to as Antoni A type tissue) intermingled with regions of more loosely textured polymorphic Schwann cells (referred to as Antoni B type tissue) [4]. The clinical presentation of spinal schwannomas commonly involves localized pain or complications arising from the compression of adjacent neural structures [4]. Symptoms may include radiating pain, weakness, and sensory deficit in the distribution of the affected spinal nerve.

The approach to treatment varies, ranging from observation for small asymptomatic tumors to surgical resection for large, symptomatic tumors [7]. In cases of recurrent tumors or when surgery is not a viable option, radiation therapy may be used [8,9]. In this context, we present a case of recurrent schwannoma of the first sacral nerve with refractory neuropathic pain. The patient exhibited differential responses to Spinal Cord Stimulation (SCS) and Dorsal Root Ganglion (DRG) stimulation, with the latter providing dramatic pain relief and a significant improvement in overall quality of life.

Case Presentation

The patient, a 55-year-old male, has a significant medical history involving depression and a schwannoma affecting his sacral (S1) spinal nerve root. This condition has led to severe right lower back and leg pain. Initially, in December 2007, the patient underwent laminectomy and resection, resulting in relief for over nine years. However, a recurrence was identified in April 2017, leading to an attempted laminectomy and resection in June 2017. Unfortunately, the tumor’s intricate connection with the S1 nerve precluded successful resection. Subsequently, the patient faced challenges in mobility, relying on a wheelchair due to persistent low back pain and weakness in the right lower extremity. Chronic steroid therapy and opioids were prescribed, and the patient underwent stereotactic radiotherapy in September 2017. Despite these interventions, debilitating pain persisted, prompting a referral to a pain clinic. At the pain clinic, the patient reported daily pain levels of 9-10/10, describing it as sharp and stabbing, predominantly located in the lower back, groin, and radiating down the right lateral leg. Functional disability was severe, affecting daily activities and exacerbating depression. A multimodal pain regimen was initiated but provided inadequate relief. Given the persistent pain, a spinal SCS device was recommended. Following a successful trial, a permanent SCS implant was placed in January 2018, providing partial relief.

Despite the improvement, the patient sought evaluation at the Cleveland Clinic Foundation pain clinic in June 2018 for ongoing right low back and lower extremity pain, rated 8/10. Further adjustments to the pain regimen were made, including the addition of Duloxetine and Lidocaine patch. Notably, the patient demonstrated reduced OxyContin dosage and improved functionality. However, the pain persisted, prompting a diagnostic right S1 transforaminal epidural steroid injection. After receiving no relief from the injection, a DRG stimulation trial was conducted in December 2018. The patient reported substantial improvement, with a 60% reduction in pain, enhanced mobility, and improved quality of life. Consequently, a permanent DRG stimulation implant was performed in February 2019 (Figure 1), resulting in remarkable pain reduction to approximately 2/10. Post-implant, the patient experienced a transformative outcome, discontinuing opioids for three months and reporting enhanced sleep and daily activities. His quality of life significantly improved, and he described the therapy as “life-changing.” During a recent visit in December 2023, the patient remained enthusiastic about the sustained pain relief and reported successful discontinuation of OxyContin, gabapentin, and Cymbalta. Current pain management includes Hydrocodone/acetaminophen, Ibuprofen, and Lidocaine patch. The patient expressed gratitude for the positive impact of DRG stimulation on his life.

Figure 1: Lateral and Posterior-Anterior Fluoroscopy Imaging following Permanent DRG Stimulator Implantation.