(Kiosk 2) Midline Lower Back Pain Presenting with Bilateral Muscle Atrophy-a Case Report

Case Diagnosis: Midline lower back pain with bilateral muscle atrophy

Case Description or Program Description: 31-year-old male without medical history presented with midline low back pain and thoracic pain for one month after moving heavy objects at home. Pain was non-radiating, worse with bending with no associated numbness, tingling, or weakness in the extremities. He had no previous injuries or surgeries. Work history was significant for metal work. Physical exam showed extensive bilateral atrophy of lumbar paraspinal muscles, tenderness at midline L3-5, and positive Kemp’s test. X-ray of the lumbar spine was unremarkable. MRI whole spine without contrast revealed T9-L1 right erector spinae muscle atrophy and complete atrophy of the lower lumbar and sacral medial tract paraspinal muscle. Electrodiagnostic studies were unrevealing for denervation potentials in the thoracolumbar paraspinals. The patient was started on physical therapy.

Setting: Outpatient Clinic

Assessment/Results: Patient was sent for physical therapy and referred to neurology for further workup

Discussion (relevance): Back pain is one of the most common causes of disability nationwide with an annual cost of 20-50 billion dollars. It is categorized as acute or chronic. The differentia varies and includes muscle strain, osteoarthritis, radiculopathy, herniations, or stenosis. Treatment starts conservatively with oral pain medications, physical therapy, or epidural injections with surgery as a last resort. Prior studies investigated the relationship between muscle atrophy and lower back pain. However, the majority focused on the multifidus muscle or unilateral pain with erector spinae atrophy. Our case exhibits extensive erector spinae atrophy in the setting of midline pain and bilateral atrophy.

Conclusions: Lower back pain can present in various ways. Despite the common association of lower back pain with multifidus atrophy, it is important to note that the erector spinae can also be atrophied and present as bilateral back pain. Knowing the affected muscles can help direct treatment plans and physical therapy exercises for an optimal outcome.