Pediatric Lumbar Spondylolysis in the Setting of an Undetermined Neuropathic Process: A Case Report

Case Diagnosis: Lumbar spondylolysis in a child with contralateral lower extremity weakness and atrophy

Case Description or Program Description: A previously healthy, recently immigrated two-year-old female presented with one year history of right lower extremity weakness and impaired gait. Although able to ambulate independently at 1 year old, she sustained a fall from a cinder block onto her right hip at 14 months. Pain and weakness followed immediately, but evaluation in Central America was reportedly normal, including MRI and EMG. Despite eight months of physical therapy, family noted atrophy of her hip flexors and knee extensors. Due to ongoing circumduction gait and inability to ambulate unassisted, she presented for reevaluation one month after immigrating. Workup was largely unremarkable, but radiographs, MRI of lumbar spine and pelvis, and triple phase bone scan were significant for left L5 pars fracture and atrophy of right gluteal and proximal thigh musculature. EMG supported a chronic neurogenic process involving at least L4 and L5 on the right. She was discharged with a walker and outpatient follow up.

Setting: Tertiary Pediatric Medical Center

Assessment/Results: Serial imaging showed interval healing of her spondylolysis. Nerve conduction studies were normal on repeat EDX six months later, although needle study showed an acute on chronic neurogenic process involving L4-S1 on the right. Despite no clear etiology for her symptoms, she had mildly improved strength and was using her walker less at 10 months following presentation. She was referred to physical therapy to consider FES.

Discussion (relevance): Spondylolysis is a result of a stress fracture of the pars interarticularis, can be precipitated by trauma, and is often associated with athletic activity requiring repetitive spine extension and rotation. Patients with spondylolysis typically present with low back pain without neurologic deficits.

Conclusions: While rare, pediatric lumbar spondylolysis can present in the absence of athletic activity and may be incidentally identified during workup of other pathologies.