Thoracic medial branch peripheral nerve stimulation for adjacent segment pain in a patient with a long construct fusion: a case report.

Background: Adjacent segment degeneration is a known late complication of long construct fusions. While several experimental treatment options exist, including medial branch blocks, no definitive treatment options have been identified. Previous studies have demonstrated the benefit of restorative stimulation of the erector spinae group on patients' pain, physical function, and disability. This case hypothesizes that motor and sensory programming at the segment adjacent to the long-construct fusion has the potential to be both therapeutic for this patient's adjacent segment thoracic pain and protective through improved muscular stability. Case Description: A 71-year-old woman with a past medical history of rheumatoid arthritis and prior T11 to S1 laminectomy with fusion and bilateral pedicle osteotomy presented with moderately severe 7/10 adjacent segment pain. She had previously completed conservative therapy, including physical therapy, epidural steroid injections, and medication management with NSAIDs, muscle relaxants, anticonvulsants, topical lidocaine, and chronic daily opioid use totally 30 morphine milliequivalents daily, without significant relief. Physical exam was significant for bilateral T8-T10 facet pain and flat back kyphosis, without focal or motor sensory deficits. She underwent a peripheral nerve stimulator device implantation with bilateral four electrode leads placed at the bilateral T10 medial branches using a minimally invasive retrograde approach to accommodate the fusion. Leads were advanced in a cephalad to caudad direction aimed at the transverse process of T9. Stimulation was programmed using a combined motor- and sensory-based approach to address both functional restoration and pain control. An external therapy disc was utilized to deliver stimulation, allowing the patient to independently apply and remove therapy, supporting day-to-day management of stimulation based on symptom severity, activity level, and personal preference. At her 3-month follow-up, the patient reports significant relief in her pain with an average pain score of 3/10, improved physical function, and a decrease in her pain medication usage. Conclusions: Restorative neuromodulation using motor and sensory programming is a potentially effective treatment adjunct for select patients with adjacent segment degeneration, with treatment sessions aligned towards pain relief and functional restoration. Further studies are needed to better define its role, protective effects and expected outcomes in this patient population.