Restorative neuromodulation for chronic lumbar spine pain secondary to a long construct spinal fusion: a case report

Persistent low back pain is a known complication of long construct fusions, often resulting in long term impacts on patients' physical function. While available treatment options manage patients' pain, there are few options available that also work to improve the patients' physical function. Prior studies have demonstrated the benefit of restorative stimulation of the multifidus muscles on patients' pain, function, and disability levels. This case hypothesizes that medial branch restorative neuromodulation at the L2 segment may be therapeutic for the patient's chronic lumbar spine pain, and potentially protective through improved multifidi stability.

A 70-year-old female with a past medical history of rheumatoid arthritis, scoliosis status post multiple long-construct spinal fusions now fused to T10 to Pelvis, presented with significant chronic lumbar spine and leg pain. The patient presented to the clinic with 9/10 pain around the T9-T10 level and bilateral iliac crests. Her current pain management regimen included chronic hydrocodone and duloxetine, with minimal benefit for pain, and a home exercise program. Physical exam was significant for flat back kyphosis and S-shaped scoliosis with associated paraspinal muscle spasm. Prone instability and multifidus lift testing were positive bilaterally, and there was magnetic resonance imaging (MRI) evidence of multifidus atrophy. She underwent a permanent peripheral nerve stimulator placement, with lead placement at the L2 medial branches bilaterally, to provide restorative motor stimulation of the multifidus muscle. She completed 30-minute, twice daily restorative motor stimulation sessions. At her most recent follow-up visit, she reports pain is now 6/10, with improvement in several Patient-Reported Outcomes Measurement Information System (PROMIS)-29 domains. Additionally, the patient reports experiencing notable strong contractions of multifidus muscles bilaterally during stimulation sessions. She reports improvements in her quality of life, ability to walk without her cane, and less difficulty with activities of daily living.

Restorative neuromodulation using motor programming may represent a potential adjunctive intervention for management of post-fusion pain in select patients by improving segmental stability. The device implantation is minimally invasive, and therapeutic sessions are aligned with functional restoration. Further study is needed to better define its role, mechanisms, and expected outcomes in post-surgical populations.