Abstract
Introduction
Intraoperative neurophysiologic monitoring (IOM) is nowadays extensively used to minimize neurological morbidity in tethered cord surgery. Our goal is to describe and discuss the standard IOM techniques used during these surgical procedures and to summarize our clinical experience using a multimodal IOM approach.
Material and methods
Neurophysiological mapping of the conus-cauda is performed through direct stimulation of these structures and bilateral recording from segmental target muscles. While mapping identifies ambiguous neural structures, their functional integrity during surgery can be assessed by monitoring techniques only, such as somatosensory evoked potentials (SEPs), transcranial motor-evoked potentials (MEPs) from the limb muscles and anal sphincters, and the bulbocavernosus reflex (BCR).
Results
Between 2002 and 2012, we performed 48 surgical procedures in 47 patients with a tethered cord secondary to a variety of spinal dysraphisms. The monitorability rate was 84 % for SEPs, 97 % for limb muscle MEPs, 74 % for the anal sphincter MEPs, and 59 % for the BCR. In all patients but one, SEP, MEP, and BCR remained stable during surgery. Postoperatively, two out of 47 patients presented a significant—though transient—neurological worsening. In six patients, an unexpected muscle response was evoked by stimulating tissue macroscopically considered as not functional.
Conclusions
Mapping techniques allow identifying and sparing functional neural tissue and vice versa to cut nonfunctional structures that may contribute to cord tethering. Monitoring techniques, MEP and BCR in particular, improve the reliability of intraoperative neurophysiology, though these may require a higher degree of neuromonitoring expertise. IOM minimizes neurological morbidity in tethered cord surgery.
Similar content being viewed by others
References
Sala F, Krzan MJ, Deletis V (2002) Intraoperative neurophysiological monitoring in pediatric neurosurgery: why, when, how? Childs Nerv Syst 18(6–7):264–287
Sala F, Manganotti P, Grossauer S, Tramontanto V, Mazza C, Gerosa M (2010) Intraoperative neurophysiology of the motor system in children: a tailored approach. Childs Nerv Syst 26(4):473–490
Choux M, Lena G, Genitori L, Foroutan M (1994) The surgery of occult spinal dysraphism. Adv Tech Stand Neurosurg 21:183–238
Pierre-Kahn A, Zerah M, Renier D, Cinalli G, Sainte-Rose C, Lellouch-Tubiana A, Brunelle F, Le Merrer M, Giudicelli Y, Pichon J, Kleinknecht B, Nataf F (1997) Congenital lumbosacral lipomas. Childs Nerv Syst 13(6):298–334, discussion 335
Pang D, Wilberger JE Jr (1982) Tethered cord syndrome in adults. J Neurosurg 57(1):32–47
Pang D, Zovickian J, Moes GS (2011) Retained medullary cord in humans: late arrest of secondary neurulation. Neurosurgery 68(6):1500–1519, discussion 1519
Pouratian N, Elias WJ, Jane JA Jr, Phillips LH 2nd, Jane JA (2010) Electrophysiologically guided untethering of secondary tethered spinal cord syndrome. Neurosurg Focus 29(1):E3
Kothbauer KF, Deletis V (2010) Intraoperative neurophysiology of the conus medullaris and cauda equina. Childs Nerv Syst 26(2):247–253
Phillips LH 2nd, Jane JA (1996) Electrophysiologic monitoring during tethered spinal cord release. Clin Neurosurg 43:163–174
Legatt AD, Schroeder CE, Gill B, Goodrich JT (1992) Electrical stimulation and multichannel EMG recording for identification of functional neural tissue during cauda equina surgery. Childs Nerv Syst 8(4):185–189
Pang D, Zovickian J, Oviedo A (2009) Long-term outcome of total and near-total resection of spinal cord lipomas and radical reconstruction of the neural placode, part I: surgical technique. Neurosurgery 65(3):511–528, discussion 528–9
von Koch CS, Quinones-Hinojosa A, Gulati M, Lyon R, Peacock WJ, Yingling CD (2002) Clinical outcome in children undergoing tethered cord release utilizing intraoperative neurophysiological monitoring. Pediatr Neurosurg 37(2):81–86
Deletis V (2001) Neuromonitoring. In: McLone DG (ed) Pediatric neurosurgery: surgery of the developing nervous system. Saunders, Philadelphia, pp 1204–1213
Rodi Z, Vodusek DB (2001) Intraoperative monitoring of the bulbocavernosus reflex: the method and its problems. Clin Neurophysiol 112(5):879–883
Huang JC, Deletis V, Vodusek DB, Abbott R (1997) Preservation of pudendal afferents in sacral rhizotomies. Neurosurgery 41:411–415
Lang FF, Deletis V, Cohen HW, Velasquez L, Abbott R (1994) Inclusion of the S2 dorsal rootlets in functional posterior rhizotomy for spasticity in children with cerebral palsy. Neurosurgery 34:847–853
Pechstein U, Cedzich C, Nadstawek J, Schramm J (1996) Transcranial high-frequency repetitive electrical stimulation for recording myogenic motor evoked potentials with the patient under general anesthesia. Neurosurgery 39:335–344
Taniguchi M, Cedzich C, Schramm J (1993) Modification of cortical stimulation for motor evoked potentials under general anesthesia: technical description. Neurosurgery 32:219–226
MacDonald DB (2002) Safety of intraoperative transcranial electrical stimulation motor evoked potential monitoring. J Clin Neurophysiol 19(5):416–429
Deletis V, Vodusek DB (1997) Intraoperative recording of the bulbocavernosus reflex. Neurosurgery 40:88–93
Jellinek D, Jewkes D, Symon L (1991) Noninvasive intraoperative monitoring of motor evoked potentials under propofol anesthesia: effect of spinal surgery on the amplitude and latency of motor evoked potentials. Neurosurgery 29:551–557
Kalkman CJ, Drummond JC, Ribberink AA, Patel PM, Sano T, Bickford RG (1992) Effects of propofol, etomidate, midazolam and fentanyl on motor evoked responses to transcranial electrical or magnetic stimulation in humans. Anesthesiology 76:502–509
Sloan T (2010) Anesthesia and intraoperative neurophysiological monitoring in children. Childs Nerv Syst 26(2):227–235
Polo A, Zanette G, Manganotti P, Bertolasi L, De Grandis D, Rizzuto N (1994) Spinal somatosensory evoked potentials in patients with tethered cord syndrome. Can J Neurol Sci 21(4):325–330
Roy MW, Gilmore R, Walsh JW (1986) Evaluation of children and young adults with tethered spinal cord syndrome. Utility of spinal and scalp recorded somatosensory evoked potentials. Surg Neurol 26(3):241–248
Boor R, Schwarz M, Reitter B, Voth D (1993) Tethered cord after spina bifida aperta: a longitudinal study of somatosensory evoked potentials. Childs Nerv Syst 9(6):328–330
Pang D, Casey K (1983) Use of an anal sphincter pressure monitor during operations on the sacral spinal cord and nerve roots. Neurosurgery 13(5):562–568
Lueders H, Hahn J, Gurd A, Tsuji S, Dinner D, Lesser R, Klem G (1982) Surgical monitoring of spinal cord function: cauda equina stimulation technique. Neurosurgery 11(4):482–485
Lindsay KW, Teasdale GM (1980) Electrophysiological identification of nerve roots during operations for spinal dysraphism. Surg Neurol 14(1):49–51
James HE, Mulcahy JJ, Walsh JW, Kaplan GW (1979) Use of anal sphincter electromyography during operations on the conus medullaris and sacral nerve roots. Neurosurgery 4(6):521–523
Kothbauer K, Schmid UD, Seiler RW, Eisner W (1994) Intraoperative motor and sensory monitoring of the cauda equina. Neurosurgery 34(4):702–707, discussion 707
Kumar GS, Rajshekhar V, Babu KS (2006) Intraoperative mapping of sacral nervous system (S2-4). Br J Neurosurg 20(6):396–402
Lee GY, Paradiso G, Tator CH, Gentili F, Massicotte EM, Fehlings MG (2006) Surgical management of tethered cord syndrome in adults: indications, techniques, and long-term outcomes in 60 patients. J Neurosurg Spine 4(2):123–131
Quinones-Hinojosa A, Gadkary CA, Gulati M, von Koch CS, Lyon R, Weinstein PR, Yingling CD (2004) Neurophysiological monitoring for safe surgical tethered cord syndrome release in adults. Surg Neurol 62(2):127–133, discussion 133–5
Shinomiya K, Fuchioka M, Matsuoka T, Okamoto A, Yoshida H, Mutoh N, Furuya K, Andoh M (1991) Intraoperative monitoring for tethered spinal cord syndrome. Spine 16(11):1290–1294 (Phila Pa 1976)
Husain AM, Shah D (2009) Prognostic value of neurophysiologic intraoperative monitoring in tethered cord syndrome surgery. J Clin Neurophysiol 26(4):244–247
Krieger D, Sclabassi RJ (1995) Neurophysiologic assessment in the management of spinal dysraphism. Neurosurg Clin N Am 6(2):219–230
Krassioukov AV, Sarjeant R, Arkia H, Fehlings MG (2004) Multimodality intraoperative monitoring during complex lumbosacral procedures: indications, techniques, and long-term follow-up review of 61 consecutive cases. J Neurosurg Spine 1(3):243–253
Beyazova M, Zinnuroglu M, Emmez H, Kaya K, Ozkose HZ, Baykaner MK, Erden Z, Orucoglu N, Ozturk GT, Erdogan Z (2010) Intraoperative neurophysiological monitoring during surgery for tethered cord syndrome. Turk Neurosurg 20(4):480–484
Hoving EW, Haitsma E, Oude Ophuis CM, Journee HL (2011) The value of intraoperative neurophysiological monitoring in tethered cord surgery. Childs Nerv Syst 27(9):1445–1452
Stavrinou P, Kunz M, Lehner M, Heger A, Muller-Felber W, Tonn JC, Lehner M, Heger A, Muller-Felber W, Tonn JC, Peraud A (2011) Children with tethered cord syndrome of different etiology benefit from microsurgery—a single institution experience. Childs Nerv Syst 27(5):803–810
Barley JL, Mooney JF, Glazier SS, Johnson T, Kornegay AL, Turner RP, Edwards JC (2010) Sudden appearance of new upper extremity motor function while performing neurophysiologic intraoperative monitoring during tethered cord release: a case report. J Pediatr Orthop 30(6):624–628
Yingling CD (2011) Are there false-negative and false-positive motor-evoked potentials? J Clin Neurophysiol 28(6):607–610
Sala F, Chang D, Kržan M, Epstein FJ, Deletis V (2000) Reliability of neurophysiological monitoring of the lumbosacral nervous system during tethered cord release. Childs Nerv Syst 16:374 (abstract)
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Sala, F., Squintani, G., Tramontano, V. et al. Intraoperative neurophysiology in tethered cord surgery: techniques and results. Childs Nerv Syst 29, 1611–1624 (2013). https://doi.org/10.1007/s00381-013-2188-3
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00381-013-2188-3