Cauda equina injury: late motor recovery

A 21-year-old man was left with complete paraplegia and lower extremity sensory loss after a gunshot wound to the 4th lumbar vertebral body. Within three weeks of the injury he noted slight recovery of proximal left leg movements. With further motor recovery and rehabilitation, he was discharged ambulatory at nine months postinjury. The patient described late motor recovery developing 13 to 16 years after injury, particularly in right knee extensors and bilateral ankle plantar flexors, simultaneous with an aggressive home exercise program. Serial manual muscle tests revealed increased strength in hip flexors, knee flexors and extensors, and ankle plantar flexors. The patient progressed from ambulating with bilateral knee-ankle orthoses and forearm crutches to bilateral ankle-foot orthoses and a point cane. His original injury was a combination of neurapraxia, which recovered by resolution of conduction block in several weeks to months; axonotmesis, which recovered by axon regeneration over several years; and neurotmesis, which did not recover. The muscle strengthening achieved 14 years after cauda equina injury may represent strengthening of muscle fibers reiinervated after the initial nine-month rehabilitation program. Clinical implications for rehabilitation are discussed including the possible need for a therapeutic trial of muscle strengthening.