Neurophysiological Monitoring of S1 Root Function During Microsurgical Posterior Discectomy Using H-Reflex and Spinal Nerve Root Potentials

Abstract

A good surgical outcome as shown by preserved Achilles tendon and H reflexes was related to the immediate return of H wave and SRP on stopping the harmful manipulation, and preservation of the H wave and SRP at the end of surgery.SRP monitoring brings up additional information concerning initial root injury and cumulative manipulative effects. The technique of dynamic nerve root retraction in posterior lumbar discectomy can therefore be made safer.

H-reflex amplitude asymmetry is an earlier sign of nerve root involvement than latency in patients with S1 radiculopathy

“…Conduction blockage reduces the traveling neural signal in the nerve root [13]. It also results in desychronisation of input signal [16]. This decreased motoneuron recruitment and in amplitude reduction of descendant volley and H reflex [13,16].…”

“…It also results in desychronisation of input signal [16]. This decreased motoneuron recruitment and in amplitude reduction of descendant volley and H reflex [13,16]. As the severity (i.e., increase in the duration of symptoms and distal involvement of lower limbs pain, numbness, tingling, and weakness) of nerve root involvement progressed, the H-reflex amplitude asymmetry and abnormal latency were more pronounced.…”

Intraoperative Mapping of Roots, Plexuses, and Nerves

“…The soleus H-reflex and nerve root action potentials have been used in surgeries involving sacral nerve root manipulation, to assess potential damage to the nerve root and warn the surgeon of prolonged or forceful retraction. Preservation of the H-reflex and nerve root potentials during posterior lumbar discectomy has been shown to correlate well with good surgical outcome (Bosnjak and Makovek, 2010).…”

Intraoperative neurophysiologic monitoring with Hoffmann reflex during thoracic spine surgery

“…Complication rates vary with each type of procedure. For example, 1-15% of patients in a series experienced aggravated or de novo motor or sensory symptoms following various spine stabilization surgeries [1]. Crucially, debilitating spinal cord ischemia can occur during surgeries involving the thoracic spine due to injury to the artery of Adamkiewicz, a major vessel that supplies the spinal cord in the thoracolumbar region [2].…”