A multicentre retrospective review of muscle necrosis of the leg following spinal surgery with motor evoked potential monitoring: a cause for concern?

purposeThere are very few reported cases of compartment syndrome of the leg following spinal surgery via a posterior approach. An association between compartment syndrome and muscle over-activity via nerve stimulation during evoked potential monitoring was first suggested in 2003. No further reports have suggested this link. We present a multicentre retrospective review of a series of five patients who developed compartment syndrome of the leg following spinal surgery via a posterior approach, whilst un-paralysed and with combined sensory (SSEP)/motor evoked potential (MEP) monitoring with an aim of highlighting this possible causative factor.

methodsAll data were collected contemporaneously and retrospective analysis was performed. We then arranged for a multidisciplinary review of the cases including surgeons, anaesthetists, radiologists, neurophysiologists and theatre and ward nursing staff. Finally, the literature was reviewed.

resultsAll patients were operated on by three different surgeons, on different operating tables/mattresses in the prone position. The common factors were un-paralysed patients having motor/sensory monitoring, mechanical calf pumps and total intravenous anaesthesia. Three patients underwent surgical decompression of their compartments and two were treated expectantly. Three patients had confirmed intra-compartmental changes on MRI consistent with compartment syndrome and one had intra-compartmental pressure monitoring which confirmed the diagnosis.

conclusionsPrevious cases in the literature have related to mal-positioning on the Jackson table or use of the knee-chest position for surgery. This was not the case for our patients; therefore, we suspect an association between overactive muscle stimulation and muscle necrosis. Further experimental studies investigating this link are required.