Spinal cord injury: association with axonal peripheral neuropathy in severely paralysed limbs

Abstract

Pressure sores are a major health problem in spinal cord injury (SCI). In this population pressure damage to peripheral nerves was not thoroughly investigated so far. However, intact peripheral nerves and innervated muscles are a prerequisite for the effectiveness of supportive therapies like functional electrical stimulation (FES). We assessed electroneurographic (ENG) data of lower limbs in SCI individuals admitted to our hospital due to severe pressure sores. Our centers prospectively acquired ENG data of the European Multicenter study about SCI (EMSCI) patients served as early control. In the pressure sore cohort (n = 15) all patients were sensory-motor complete (American Spinal Cord Injury Association Impairment Scale A). Most patients (10/15) suffered from a severe axonal sensory-motor polyneuropathy in paralysed legs with absent compound muscle action potentials (CMAPs) of tibial/peroneal nerves as well as absent sensory nerve action potentials of sural nerves. The onset of this polyneuropathy dates within the first year after incident SCI and was mainly associated with increasing sensory-motor completeness as demonstrated by a significant CMAP drop of our centers EMSCI-ENG data on serial tibial nerve recordings in 275 patients. Severe SCI is associated with an early-onset axonal polyneuropathy in paralysed limbs to which pressure damage might contribute. Because intact peripheral nerves are required for: (i) maintenance of motor function in centrally impaired muscles; and (ii) effectiveness of supportive therapies like FES, ENG-monitoring could serve as a low invasive screening method for peripheral nerve integrity in patients with SCI to initiate pressure relief procedures early enough.