Intraoperative neurophysiological monitoring in surgery of lumbar spinal stenosis

Background. Lumbar spinal stenosis is a pathological constriction of the central spinal canal, lateral pocket or intervertebral foramen. The complication rate of lumbar spinal stenosis surgery ranges from 10 to 24 %. In order to reduce the number of intraoperative and early postoperative complications accompanied by the development of neurological deficit, various techniques of intraoperative neurophysiological monitoring are used.Aim. Study of informativity of the use of intraoperative neurophysiological monitoring during surgical treatment of degenerative lumbar spinal stenosis based on the experience of the neurosurgical department of the Republican Clinical Hospital (Yoshkar‑Ola, Mari El Republic).Materials and methods. Thus, 69 decompressive‑stabilizing surgical interventions for degenerative lumbar spinal stenosis at the L3–L5 level, performed with intraoperative neurophysiological monitoring (free‑run electromyography, transcranial motor evoked potentials, somatosensory evoked potentials, triggered electromyography were included in the retrospective study).Results. During intraoperative neurophysiological monitoring transcranial motor evoked potentials from the legs was registered in all cases. Normal somatosensory evoked potentials were recorded in most cases, in 12 cases (17.4 %) baseline somatosensory evoked potentials were not registered due to preoperative neurological deficits and the presence of concomitant somatic pathology. 308 inserted pedicular screws were examined using the triggered electromyography. Muscle responses were registered in 31 (45 %) operations, 45 (14 %) screws. True negatives were registered with 29 (64.4 %), true positives were registered with 12 (26.7 %), and false positives were registered with 4 (8.9 %) screws. In the postoperative period no increase in motor and sensory neurological deficits was observed in all patients; no neurological signs of screw malpositioning were revealed.Conclusion. The use of multimodal intraoperative neurophysiological monitoring during surgical treatment of lumbar spinal stenosis reduces the risk of postoperative neurological complications.