Spinal cord mapping as an adjunct for resection of intramedullary tumors: Surgical technique with case illustrations

Alfredo Quinones-Hinojosa, Mittul Gulati, Russell Lyon, Nalin Gupta, Charles Yingling, Paul R. Cooper, Edward C. Benzel, Volker K.H. Sonntag, Paul C. McCormick

Research output: Contribution to journalArticlepeer-review

58 Scopus citations


OBJECTIVE: Resection of intramedullary spinal cord tumors may result in transient or permanent neurological deficits. Intraoperative somatosensory evoked potentials (SSEPs) and motor evoked potentials are commonly used to limit complications. We used both antidromically elicited SSEPs for planning the myelotomy site and direct mapping of spinal cord tracts during tumor resection to reduce the risk of neurological deficits and increase the extent of tumor resection. METHODS: In two patients, 3 and 12 years of age, with tumors of the thoracic and cervical spinal cord, respectively, antidromically elicited SSEPs were evoked by stimulation of the dorsal columns and were recorded with subdermal electrodes placed at the medial malleoli bilaterally. Intramedullary spinal cord mapping was performed by stimulating the resection cavity with a handheld Ojemann stimulator (Radionics, Burlington, MA). In addition to visual observation, subdermal needle electrodes inserted into the abductor pollicis brevis-flexor digiti minimi manus, tibialis anteriorgastrocnemius, and abductor halluces-abductor digiti minimi pedis muscles bilaterally recorded responses that identified motor pathways. RESULTS: The midline of the spinal cord was anatomically identified by visualizing branches of the dorsal medullary vein penetrating the median sulcus. Antidromic responses were obtained by stimulation at 1-mm intervals on either side of the midline, and the region where no response was elicited was selected for the myelotomy. The anatomic and electrical midlines did not precisely overlap. Stimulation of abnormal tissue within the tumor did not elicit electromyographic activity. Approaching the periphery of the tumor, stimulation at 1 mA elicited an electromyographic response before normal spinal cord was visualized. Restimulation at lower currents by use of 0.25-mA increments identified the descending motor tracts adjacent to the tumor. After tumor resection, the tracts were restimulated to confirm functional integrity. Both patients were discharged within 2 weeks of surgery with minimal neurological deficits. CONCLUSION: Antidromically elicited SSEPs were important in determining the midline of a distorted cord for placement of the myelotomy incision. Mapping spinal cord motor tracts with direct spinal cord stimulation and electromyographic recording facilitated the extent of surgical resection.

Original languageEnglish (US)
Pages (from-to)1199-1207
Number of pages9
Issue number5
StatePublished - Nov 1 2002


  • Direct stimulation spinal cord
  • Electrophysiological monitoring
  • Intramedullary spinal cord tumor
  • Intraoperative mapping
  • Motor evoked potentials
  • Somatosensory evoked potentials

ASJC Scopus subject areas

  • Surgery
  • Clinical Neurology


Dive into the research topics of 'Spinal cord mapping as an adjunct for resection of intramedullary tumors: Surgical technique with case illustrations'. Together they form a unique fingerprint.

Cite this