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Vaithialingam B, Haran V, Rudrappa S. Intra-operative Triggered EMG Monitoring - "Total Intravenous Anesthesia is not Indispensable". Neurol India 2024; 72:425-426. [PMID: 38691492 DOI: 10.4103/neurol-india.neurol-india-d-23-00556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 02/20/2024] [Indexed: 05/03/2024]
Affiliation(s)
- Balaji Vaithialingam
- Division of Neuroanaesthesia, International Institute of Neurosciences, Aster Whitefield Hospital, Bengaluru, Karnataka, India
| | - Vignesh Haran
- Department of Neurology, Manipal Hospital, Old Airport Road, Bengaluru, Karnataka, India
| | - Satish Rudrappa
- Department of Neurosurgery and Spine Surgery, International Institute of Neurosciences, Aster Whitefield Hospital, Bengaluru, Karnataka, India
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Abu-Ata MM, Pasquali C, Sala F. Intraoperative Neuromonitoring in Tethered Cord Surgery in Children. J Clin Neurophysiol 2024; 41:123-133. [PMID: 38306220 DOI: 10.1097/wnp.0000000000001056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2024] Open
Affiliation(s)
- Mahmoud M Abu-Ata
- Center of Neurosciences, King Faisal Specialty Hospital and Research Center, Riyadh, Saudi Arabia; and
| | - Claudia Pasquali
- Department of Neurosciences, Institute of Neurosurgery, University Hospital, Verona, Italy
| | - Francesco Sala
- Department of Neurosciences, Institute of Neurosurgery, University Hospital, Verona, Italy
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Ogawa Y, Hayashi H, Sasaki R, Takatani T, Oi A, Uemura K, Kawaguchi M. Motor-evoked potential monitoring from urinary sphincter muscle during pediatric untethering surgery: a case series. Childs Nerv Syst 2023; 39:2147-2153. [PMID: 36890423 DOI: 10.1007/s00381-023-05895-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 02/22/2023] [Indexed: 03/10/2023]
Abstract
PURPOSE Postoperative urinary dysfunction following untethering surgery for spinal lipoma is devastating. To assess urinary function, we invented a pediatric urinary catheter equipped with electrodes for the direct transurethral recording of myogenic potential from the external urethral sphincter (EUS). This paper presents two cases in which urinary function was monitored intraoperatively by recording of motor-evoked potential (MEP) from EUS during untethering surgery in children. METHODS Two children (aged 2 and 6 years) were included in this study. One patient had no preoperative neurological dysfunction, while the other had frequent urination and urinary incontinence. A pair of surface electrodes was attached to a silicone rubber urethral catheter (6 or 8 Fr; diameter, 2 or 2.6 mm). The MEP from the EUS was recorded to assess the function of the centrifugal tract from the motor cortex to the pudendal nerve. RESULTS Baseline MEP waveforms from the EUS were successfully recorded with latency and amplitude of 39.5 ms and 66 µV in patient 1 and 39.0 ms and 113 µV in patient 2, respectively. A significant decrease in amplitude was not observed during surgery in the two cases. No new urinary dysfunction and complications associated with the urinary catheter-equipped electrodes developed postoperatively. CONCLUSION Using an electrode-equipped urinary catheter, monitoring of MEP from the EUS could be applicable during untethering surgery in pediatric patients.
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Affiliation(s)
- Yuki Ogawa
- Department of Anesthesiology, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8521, Japan
| | - Hironobu Hayashi
- Department of Anesthesiology, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8521, Japan.
| | - Ryota Sasaki
- Department of Neurosurgery, Nara Medical University, Nara, Japan
| | - Tsunenori Takatani
- Department of Anesthesiology, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8521, Japan
| | - Ayako Oi
- Department of Anesthesiology, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8521, Japan
| | - Keiko Uemura
- Department of Anesthesiology, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8521, Japan
| | - Masahiko Kawaguchi
- Department of Anesthesiology, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, 634-8521, Japan
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TAŞKIRAN E, KEMERDERE R, KÜÇÜKYÜRÜK B, TAHMAZOĞLU B, KAFADAR AM. Mapping and Monitoring During Surgery for Congenital Spinal Malformation. BEZMIALEM SCIENCE 2022. [DOI: 10.14235/bas.galenos.2020.4452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Vaithialingam B. Anesthesia for triggered electromyography-guided cord detethering in a three-month-old infant. Saudi J Anaesth 2022; 16:270-271. [PMID: 35431744 PMCID: PMC9009558 DOI: 10.4103/sja.sja_49_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 01/19/2022] [Indexed: 12/03/2022] Open
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Dynamic mapping using an electrified ultrasonic aspirator in lipomyelomeningocele and spinal cord detethering surgery-a feasibility study. Childs Nerv Syst 2021; 37:1633-1639. [PMID: 33404721 DOI: 10.1007/s00381-020-05012-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 12/09/2020] [Indexed: 10/22/2022]
Abstract
BACKGROUND Intraoperative neurophysiologic monitoring (IONM) is an established technique and adjunct of brain and spinal lesion resection surgery. In spina bifida syndrome surgery, mapping of the surgical wound is a common and accepted method in determining the position and functionality of nerve roots of the cauda equina (CE), especially when the anatomy is not straightforward and roots are splayed across or entangled within the lesion. Here, we describe a novel technique of continuous CE mapping using an electrified cavitron ultrasonic aspirator (eCUSA) in children with lipomyelomeningocele (LMMC) lesions. METHODS We assessed a method of dynamic CE mapping using an eCUSA as a stimulation probe. Twenty children (0.5-18 years) were included in this study, diagnosed with occult spina bifida LMMC in which the eCUSA stimulator was applied. IONM data and 2-weeks post-operative data were collected. RESULTS LMMC lesions were located in the lumbar, sacral, and lumbosacral spine. eCUSA stimulation at 0.3-3.0 mA intensities elicited positive lower extremity muscle responses in 12 of the 20 patients included in the study. These responses allowed the surgeon real-time identification of the nerve roots tangent at the LMMC-cauda equina structure and intensive removal of the fat tissue in the area non-responding to the eCUSA stimulation. CONCLUSION Continuous eCUSA-based stimulation of the cauda equina during LMMC resection is a feasible mapping technique with potential added value improving safety of untethering. Future studies evaluating extension of untethering, as well as the rates of retethering and long-term neurological and urological outcomes, are warranted.
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Valentini LG, Babini M, Cordella R, Beretta E, Destro F, Murabito P, Caldiroli D, Devigili G, Selvaggio G. Early de-tethering: analysis of urological and clinical consequences in a series of 40 children. Childs Nerv Syst 2021; 37:941-949. [PMID: 32728933 DOI: 10.1007/s00381-020-04838-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 07/23/2020] [Indexed: 12/19/2022]
Abstract
PURPOSE Early de-tethering procedures are performed on spinal dysraphisms to prevent neuro-urological deterioration caused by growth. Partial lipoma removal may cause delayed deterioration by re-tethering, while complete removal may increase the risk of postoperative worsening. The present study evaluates the risk of postoperative deterioration and the protective potential of intraoperative neurophysiological monitoring (IOM), with a special reference to the conus lipomas treated with the radical approach. METHODS Forty toddlers (< 24 months) underwent complete perioperative neurological and urological assessment, including urodynamic study (UDS). The dysraphisms were subgrouped according to Pang's classification. IOM was applied in all patients: transcranial motor evoked potentials (tMep) combined with mapping were recorded in all cases while bulbocavernosus reflex (BCR) was evaluable just in 7 cases. RESULTS At preoperative evaluation, 11 children already had UDS impairment and 2 had motor disturbances before neurosurgery. At 1-month follow-up, preoperative motor disturbances were stable, 7/11 UDS alterations normalized, and the remaining 4 were stable. At 6-month follow-up, all motor deficits and 8/11 preoperative UDS alterations had improved. Unfortunately, 7 children with previously normal UDS experienced a new impairment after surgery: 2/7 normalized while 5/7 did not recover. This postoperative permanent urodynamic impairment occurred in 4 chaotic lipoma (CLchaos) and in one terminal myelocystocele (TMC) that means a surgical deterioration rate of 22% for the high risk cases. CONCLUSIONS This small highly selected series confirms that early de-tethering may stop or revert the spontaneous neuro-urological deterioration: in fact, preoperative UDS impairment was frequent (27.5%) and improved in all the low surgical risk cases (limited dorsal myeloschisis, filar, transitional and dorsal lipomas). On the contrary, in CLchaos and TMC, early de-tethering was unable to revert preoperative UDS impairment, and radical surgery carried a high risk of new neuro-urological deterioration directly caused by the operation. In our experience, IOM had a protective role for motor functions, while it was less effective for the neuro-urological ones, probably due to the anesthesiology regimens applied. In conclusion, among the dysraphisms, CLchoas proved to be the worst enemy that often camouflages at MRI. Affording it without all possible IOM weapons carries a high risk to harm the patient.
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Affiliation(s)
- Laura Grazia Valentini
- Department of Neurosurgery, Fondazione IRCCS Istituto Neurologico "Carlo Besta", 20133, Milan, Italy.
| | - Micol Babini
- Department of Neurosurgery, Fondazione IRCCS Istituto Neurologico "Carlo Besta", 20133, Milan, Italy
| | - Roberto Cordella
- Department of Neurosurgery, Fondazione IRCCS Istituto Neurologico "Carlo Besta", 20133, Milan, Italy
| | - Elena Beretta
- Department of Neurosurgery, Fondazione IRCCS Istituto Neurologico "Carlo Besta", 20133, Milan, Italy
| | - Francesca Destro
- Pediatric Surgery Unit, Children's Hospital "Vittore Buzzi", Milan, Italy
| | - Paolo Murabito
- Anesthesiology Unit, Fondazione IRCCS Istituto Neurologico "Carlo Besta", Milan, Italy
| | - Dario Caldiroli
- Anesthesiology Unit, Fondazione IRCCS Istituto Neurologico "Carlo Besta", Milan, Italy
| | - Grazia Devigili
- Department of Neurology, Fondazione IRCCS Istituto Neurologico "Carlo Besta", Milan, Italy
| | - Giorgio Selvaggio
- Pediatric Surgery Unit, Children's Hospital "Vittore Buzzi", Milan, Italy
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Kim K. Intraoperative Neurophysiology Monitoring for Spinal Dysraphism. J Korean Neurosurg Soc 2020; 64:143-150. [PMID: 32905697 PMCID: PMC7969044 DOI: 10.3340/jkns.2020.0124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Accepted: 05/02/2020] [Indexed: 11/30/2022] Open
Abstract
Spinal dysraphism often causes neurological impairment from direct involvement of lesions or from cord tethering. The conus medullaris and lumbosacral roots are most vulnerable. Surgical intervention such as untethering surgery is indicated to minimize or prevent further neurological deficits. Because untethering surgery itself imposes risk of neural injury, intraoperative neurophysiological monitoring (IONM) is indicated to help surgeons to be guided during surgery and to improve functional outcome. Monitoring of electromyography (EMG), motor evoked potential, and bulbocavernosus reflex (BCR) is essential modalities in IONM for untethering. Sensory evoked potential can be also employed to further interpretation. In specific, free-running EMG and triggered EMG is of most utility to identify lumbosacral roots within the field of surgery and filum terminale or non-functioning cord can be also confirmed by absence of responses at higher intensity of stimulation. The sacral nervous system should be vigilantly monitored as pathophysiology of tethered cord syndrome affects the sacral function most and earliest. BCR monitoring can be readily applicable for sacral monitoring and has been shown to be useful for prediction of postoperative sacral dysfunction. Further research is guaranteed because current IONM methodology in spinal dysraphism is still deficient of quantitative and objective evaluation and fails to directly measure the sacral autonomic nervous system.
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Affiliation(s)
- Keewon Kim
- Department of Rehabilitation Medicine, Seoul National University Hospital, Seoul, Korea
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Pratheesh R, Babu KS, Rajshekhar V. Improvement in intraoperative transcranial electrical motor-evoked potentials in tethered cord surgery: an analysis of 45 cases. Acta Neurochir (Wien) 2014; 156:723-31. [PMID: 24452593 DOI: 10.1007/s00701-014-1999-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2013] [Accepted: 01/09/2014] [Indexed: 11/30/2022]
Abstract
BACKGROUND Improvement of transcranial electrical motor-evoked potentials (TeMEPs) following untethering during tethered cord surgery (TCS) and its clinical significance have not been analyzed in the literature. METHODS Forty-five consecutive cases of tethered cord were operated on with multimodality intraoperative neurophysiological monitoring (IONM) between February 2005 and January 2012. Intraoperative TeMEP change was classified as improvement, worsening or no change. Motor, sensory, bladder and bowel symptoms and signs were evaluated preoperatively, in the first week post-surgery and at the last follow-up (maximum of 2 years). RESULTS Patient age ranged from 5 to 44 years (mean, 16 ± 10 years), with 30 children. Intraoperative MEPs improved in 23 (51 %), remained the same in 21 (46.7 %) and worsened in 1 (2 %) patient. Motor improvement occurred in 7 patients and clinical improvement in 17 patients in the immediate postoperative period. Postoperative neurological worsening occurred in one patient (2.2 %). Improved and stable MEPs correlated with the motor (p = 0.002) and clinical improvement (p = 0.02) in the immediate postoperative period. Follow-up was available in 35 patients (77.7 %), ranging from 5 to 24 months (median, 21 months; mean, 17.7 ± 6.8 months). There was late clinical improvement in 73.5 % of the patients in whom the intraoperative MEP had remained the same or improved. However, there was no statistically significant correlation between MEP change and long-term outcome. CONCLUSIONS Intraoperative MEP improvement occurs in about 50 % of the patients following successful untethering. This finding probably provides support to the ischemic theory of tethered cord syndrome.
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Affiliation(s)
- Ravindran Pratheesh
- Department of Neurological Sciences, Christian Medical College, Vellore, 632004, India
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Intraoperative neurophysiology in tethered cord surgery: techniques and results. Childs Nerv Syst 2013; 29:1611-24. [PMID: 24013331 DOI: 10.1007/s00381-013-2188-3] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 05/24/2013] [Indexed: 01/19/2023]
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.
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Liu H, Zhang JN, Zhu T. Microsurgical treatment of spinal epidermoid and dermoid cysts in the lumbosacral region. J Clin Neurosci 2012; 19:712-7. [PMID: 22436108 DOI: 10.1016/j.jocn.2011.07.046] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2011] [Revised: 06/27/2011] [Accepted: 07/03/2011] [Indexed: 11/24/2022]
Abstract
The aim of this study was to evaluate the characteristics and surgical outcome of spinal epidermoid and dermoid cysts in the lumbosacral spine. We reviewed 26 patients with spinal epidermoid and dermoid cysts (15 epidermoid and 11 dermoid) treated between October 2000 and December 2010. The latter 15 patients of this series underwent neurophysiological monitoring during surgery. Gross total resection of the tumour was achieved in 46.2% of patients, and 53.8% underwent subtotal resection. In 14 patients, the tumour capsule adhered so tightly to the neural structures that a section of the capsule remained in situ. After surgery, the Japanese Orthopaedic Association score improved in 80.8% of patients, remained stable in 15.4%, and declined in 3.8%. The average follow-up period was 53 months. Three patients developed recurrence of the tumour and 20 patients resumed a normal working life. Microsurgical techniques and intraoperative neurophysiological monitoring are practical and reliable methods for radical removal of spinal epidermoid and dermoid cysts that involve the conus medullaris and cauda equina.
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Affiliation(s)
- Hui Liu
- Department of Neurosurgery, Tianjin Medical University General Hospital, 154 An-Shan Road, Tianjin 300052, China
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Abstract
BACKGROUND Lipomyelomeningocele (LMM) is a common and severe closed neural tube defect in children. Because of the complex anatomy of LMM and the difficulty in assessing the value of surgery, the management of patients with LMM is controversial. This study was undertaken to evaluate effective techniques and procedures in surgical treatment of LMM and to assess the value of early neurosurgical intervention. METHODS Twenty-five children with LMM aged from 2 months to 6 years underwent surgery between January 2004 and December 2006. Magnetic resonance imaging (MRI) of the spine and electromyography (EMG) of the lower limbs was conducted in all patients preoperatively. Urodynamic studies were appropriate even in asymptomatic patients. Hoffman's functional grading was used to assess the pre and postoperative status of the patients. The operation was composed of subtotal excision of lipoma, suturing of the spinal pia mater, and section of the filum terminale. Suturing of the spinal pia mater was performed in a wide process of reconstruction of meningeal layers including the dura. Follow-up lasted 1-4 years (mean 2.1 years), in which all children underwent neurological examination, EMG and MRI. RESULTS After surgery a temporary neurological deterioration was found in two patients including slight weakness of a leg in one patient and urinary retention in the other, but it recovered completely a few days later. No postoperative complications were encountered. During the follow-up, 20 asymptomatic patients remained symptom-free. Symptoms disappeared totally in 2 of the 5 patients with neurological deficits, improved in one patient and stabilized in the remaining 2. MRI showed no tethered cord in all patients who underwent surgical procedures. CONCLUSIONS Early operation for LMM patients, even asymptomatic ones, should be performed to prevent the development of neurological deficits. Subtotal excision of lipoma, suturing of the spinal pia mater, and section of the filum terminale are recommended in the surgical treatment of LMM. The longitudinal cut of the filum terminale, a technique we have established in our surgical practice, is a simple and practical way to identify the filum terminale by visual inspection. And suturing the spinal pia mater is of extreme importance in preventing postoperative tethering.
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Abstract
PURPOSE Intraoperative neurophysiological techniques are becoming routine tools for neurosurgical practice. Procedures affecting the lumbosacral nervous system are frequent in adult and pediatric neurosurgery. This review provides an overview of the techniques utilized in cauda and conus operations. METHODS Two basic methodologies of intraoperative neurophysiological testing are utilized during surgery in the lumbosacral spinal canal. Mapping techniques help identify functional neural structures, namely, nerve roots and their respective spinal levels. Monitoring is referred to as the technology to continuously assess the functional integrity of pathways and reflex circuits. For mapping direct electrical stimulation of a structure within the surgical field and recording at a distant site, usually a muscle is the most commonly used setup. Sensory nerve roots or spinal cord areas can be mapped by stimulation of a distant sensory nerve or skin area and recording from a structure within the surgical field. Continuous monitoring of the motor system is done with motor evoked potentials. These are evoked by transcranial electrical stimulation and recorded from lower extremity and sphincter muscles. Presence or absence of muscle responses are the monitored parameters. To monitor the sensory pathways, sensory potentials evoked by tibial, peroneal, or pudendal nerve stimulation and recorded from the dorsal columns with a spinal electrode or as cortical responses from scalp electrodes are used. Amplitudes and latencies of these responses are measured for interpretation. The bulbocavernosus reflex, with stimulation of the pudendal nerve and recording from the external anal sphincter, is used for continuous monitoring of the reflex circuitry. The presence of absence of this response is the pertinent parameter monitored. Stimulation of individual dorsal nerve roots is used to identify those segments that generate spastic activity and which may be cut during selective dorsal rhizotomy. Electromyographic activity can be continuously observed during surgery, and monitoring concepts developed in cranial nerve surgery may be used in the cauda equina as well. CONCLUSION A range of intraoperative neurophysiological techniques are available for neurophysiological testing of the neural structures of conus medullaris and cauda equina.
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Prognostic value of neurophysiologic intraoperative monitoring in tethered cord syndrome surgery. J Clin Neurophysiol 2009; 26:244-7. [PMID: 19590435 DOI: 10.1097/wnp.0b013e3181b2edae] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Neurophysiologic intraoperative monitoring is used in surgery for tethered cord syndrome. Our objective was to determine if neurophysiologic intraoperative monitoring is helpful in identifying which patients will have worsening symptoms after surgery. The spinal cord was stimulated before and after untethering until a motor response was obtained. The pre- and postoperative neurologic examination findings were noted. The motor response thresholds before and after untethering were compared using Student t tests. Forty patients were identified; 37 had higher motor response thresholds before untethering, whereas in three thresholds were higher after untethering. Of the 37 patients, two had worsening of motor function. All three patients with higher thresholds after untethering had worsening of motor function (P < 0.0001). An increase in the motor response threshold after surgical release of tethered cord syndrome indicates possible worsening of clinical symptoms. Spinal cord stimulation during tethered cord syndrome surgery may help predict neurologic outcome.
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Neurophysiologic Intraoperative Monitoring During Surgery for Tethered Cord Syndrome. J Clin Neurophysiol 2009; 26:76-81. [DOI: 10.1097/wnp.0b013e31819f9067] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Ammerman JM, Kerr PB, Jarrell ST, Caputy AJ. A novel technique for the intraoperative monitoring of detrusor activity in intradural lesions of the cauda equina. Technical note. ACTA ACUST UNITED AC 2007; 68:269-71; discussion 271. [PMID: 17719960 DOI: 10.1016/j.surneu.2006.11.038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2006] [Accepted: 11/03/2006] [Indexed: 11/18/2022]
Abstract
BACKGROUND Intradural pathology in the region of the cauda equina is uncommon and generally comes to attention secondary to pain or neurologic deficit. A number of surgeons choose to excise these lesions under EMG monitoring of the nerve roots supplying the lower extremity muscles, anal sphincter, and detrusor muscle. In this article, the authors describe a detrusor muscle monitoring technique that has been found to be simple, reliable, and cost-effective in the management of intradural pathology of the cauda equina. METHODS Fourteen consecutive patients with tumors of the cauda equina who underwent surgical management performed using the standard Foley catheter monitoring technique were included in this study and their outcomes analyzed. RESULTS In 86% of patients, a gross total resection was achieved. Subtotal resections were performed in 2 patients because of involvement of critical nerve roots. In all cases, the nerve roots supplying the detrusor muscle were successfully identified using this technique. No patient suffered a clinically apparent decline in bladder function during the postoperative period. CONCLUSION The standard Foley catheter detrusor monitoring technique is a simple, reliable, and cost-effective method to identify and prevent injury to the sacral nerve roots innervating the urinary bladder during intradural exploration of the cauda equina.
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Affiliation(s)
- Joshua M Ammerman
- Department of Neurological Surgery, George Washington University School of Medicine, Washington, DC 20037, USA.
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Abstract
Electrophysiological mapping of the sacral nervous system was used during operations on 80 patients with conus and cauda equina lesions. At surgery, under controlled muscle relaxation, the sacral neural elements (S2-4) were mapped using direct mono-polar stimulation and recording of compound muscle action potentials (CMAPs) from the external anal sphincter (EAS). Responses were obtained in 86.25% (69/80) of the patients. In 33 (82.5%) out of 40 patients with preoperative deficits involving the S2-4 segments, CMAPs could be elicited. Identification of nerve roots was useful in dissection of lipomyelomeningocoeles, tumour excisions and untethering of filum terminale. In three patients, stimulation of the filum terminale elicited motor responses and, hence, it was not sectioned. Intraoperative mapping of the S2-4 nerve roots under controlled muscle relaxation is feasible in a majority of patients, including those with deficits involving S2-4. This method was useful in sparing viable nerve roots during surgery in conus and cauda equina regions, and identification of 'functional' filum terminale.
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Affiliation(s)
- G Samson Sujit Kumar
- Department of Neurological Sciences, Christian Medical College, Vellore, Tamilnadu, India
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Abstract
Tethered cord syndrome (TCS) is a diverse clinical entity characterized by symptoms and signs which are caused by excessive tension on the spinal cord. The majority of cases are related to spinal dysraphism. TCS can present in any age group, and presentations differ according to the underlying pathologic condition and age, with pain, cutaneous signs, orthopedic deformities and neurological deficits being the most common. Surgical untethering is indicated in patients with progressive or new onset symptomatology attributable to TCS. The surgical strategy aims to release the tethering structure and thus the chronic tension on the cord. Early operative intervention is associated with improved outcomes. Pain relief is accomplished in almost all cases. Realistic surgical goals include relief of pain and stabilization of neurological function, although improvement in function is often seen. Cord untethering can also halt the progression of scoliosis. The benefits of surgery are debated in asymptomatic patients and patients with normal imaging.
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Affiliation(s)
- Sean M Lew
- Department of Neurosurgery, Medical College of Wisconsin/Children's Hospital of Wisconsin, Milwaukee, WI 53226, USA.
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Paradiso G, Lee GYF, Sarjeant R, Hoang L, Massicotte EM, Fehlings MG. Multimodality intraoperative neurophysiologic monitoring findings during surgery for adult tethered cord syndrome: analysis of a series of 44 patients with long-term follow-up. Spine (Phila Pa 1976) 2006; 31:2095-102. [PMID: 16915095 DOI: 10.1097/01.brs.0000231687.02271.b6] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Prospective analysis of a consecutive series in which multimodality intraoperative neurophysiologic monitoring was used as an adjunct to microneurosurgery for adult tethered cord syndrome. The results of multimodality intraoperative neurophysiologic monitoring were compared with the "gold standard" (neurologic outcomes). OBJECTIVE To assess the sensitivity, specificity, and positive and negative predictive values of multimodality intraoperative neurophysiologic monitoring in surgery for adult tethered cord syndrome. SUMMARY OF BACKGROUND DATA Although intraoperative electrophysiologic techniques may help to minimize neural injury during spinal microneurosurgery, to our knowledge, no study has quantitatively evaluated the value of multimodality intraoperative neurophysiologic monitoring in the management of adult tethered cord syndrome. METHODS Multimodality intraoperative neurophysiologic monitoring included posterior tibial nerve somatosensory evoked potentials (SSEPs), continuous electromyographic (EMG) monitoring of the L2 to S4 myotomes, and evoked EMG. Follow-up neurologic evaluations were performed for at least 1 year. RESULTS A total of 44 consecutive patients, including 19 males and 25 females (aged 43 +/- 15 years), who underwent microsurgery for adult tethered cord syndrome were evaluated. After surgery, new neurologic deficits, including 1 transient and 1 permanent, developed in 2 patients. There was 1 patient who had persistent posterior tibial nerve SSEP amplitude reduction following microsurgical manipulation. In 1 patient, a transient posterior tibial nerve SSEP amplitude reduction prompted a change in microneurosurgical strategy. This patient awoke with no new postoperative neurologic deficits. For SSEPs, the sensitivity was 50% and specificity 100%. EMG bursts were recorded in 36 patients (82%). The 2 patients with postoperative neurologic worsening had EMG activity in the myotomes, where their new deficits presented. Continuous EMG had a sensitivity of 100% and a specificity of 19%. CONCLUSIONS To our knowledge, this is the largest series to date reporting the use of multimodality intraoperative neurophysiologic monitoring in the surgical management of adult tethered cord syndrome. Posterior tibial nerve SSEPs have high specificity, but low sensitivity, for predicting new neurologic deficits. In contrast, continuous EMG showed high sensitivity and low specificity. Evoked EMG accurately identified functional neural tissue. The combined recording of SSEPs in concert with continuous and evoked EMGs may provide a useful adjunct to complex microsurgery for adult tethered cord syndrome.
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Guo L, Quiñones-Hinojosa A, Yingling CD, Weinstein PR. Continuous EMG recordings and intraoperative electrical stimulation for identification and protection of cervical nerve roots during foraminal tumor surgery. ACTA ACUST UNITED AC 2006; 19:37-42. [PMID: 16462217 DOI: 10.1097/01.bsd.0000174566.19640.f1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Spinal cord function is now routinely monitored with somatosensory evoked potentials (SEPs) and motor evoked potentials (MEPs) during surgery for intraspinal cervical dumbbell and foraminal tumors. However, upper extremity nerve roots are also at risk during these procedures. Anatomic relations are frequently difficult to interpret because the nerve roots may be displaced by the tumor. We used electrical stimulation with compound muscle action potential (CMAP) recordings at multiple sites to identify the location and course of the involved nerve root and to provide real-time information regarding the functional status of the roots to predict postoperative outcome. METHODS Ten patients were monitored during surgery for cervical dumbbell or foraminal tumors. SEPs and MEPs were monitored as a routine procedure. CMAPs were recorded from needle electrodes placed in the deltoid, biceps, triceps, and flexor carpi ulnaris muscles. Spontaneous electromyography (EMG) muscle activity was also continuously monitored. A handheld monopolar stimulation electrode was used to elicit evoked EMG responses to identify and trace the course of nerves in relation to the tumor. In four patients, the stimulation threshold was tested before and after tumor resection to predict postoperative nerve root function. RESULTS Electrical stimulation with CMAP recording was successful in localizing nerve roots during tumor resection in all 10 patients. Monitoring predicted postoperative nerve root preservation after tumor removal in each case. It was possible to identify either by using low-level stimulation (<2.0 V) or by observing changes in spontaneous EMG amplitude if activation was present during surgical dissection. The monitoring of spontaneous muscle activity in response to direct or indirect surgical manipulation during tumor resection also provided continuous assessment of nerve root function and identified any physiologic disturbance induced by surgical manipulation. CONCLUSIONS Electrical stimulation in the operating field and recording of CMAPs facilitated nerve root identification and predicted postoperative function during dissection and separation from ligamentous or neoplastic tissue in 10 patients. Electrical stimulation might also be useful to predict postoperative preservation of function when nerve root sacrifice is necessary and no motor response is detected intraoperatively.
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Affiliation(s)
- LanJun Guo
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, CA 94143-0112, USA
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Valentini LG, Visintini S, Mendola C, Casali C, Bono R, Scaioli W, Solero CL. The role of intraoperative electromyographic monitoring in lumbosacral lipomas. Neurosurgery 2006; 56:315-23; discussion 315-23. [PMID: 15794828 DOI: 10.1227/01.neu.0000156783.03809.8a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2004] [Accepted: 12/02/2004] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE To demonstrate the role of intraoperative multichannel electromyographic (EMG) monitoring to reduce postoperative deterioration and achieve full untethering of complex occult dysraphisms. METHODS A retrospective analysis was performed on 66 patients who underwent operation for lumbosacral lipomas. Twenty recent cases were submitted to EMG monitoring and stimulation. RESULTS All patients presented symptoms at the time of surgery, and 74% exhibited progressive deterioration during the lengthy preoperative period. Postoperative surgery-related deterioration was observed in 6% of patients. This number was reduced to zero with the introduction of intraoperative EMG monitoring. CONCLUSION Intraoperative multichannel EMG monitoring can be carried out and requires only minimal changes to anesthetic procedures. With this method, it is possible to better identify the neural structures of complex malformations, reducing the risks of surgical damage and incomplete detethering.
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Krassioukov AV, Sarjeant R, Arkia H, Fehlings MG. Multimodality intraoperative monitoring during complex lumbosacral procedures: indications, techniques, and long-term follow-up review of 61 consecutive cases. J Neurosurg Spine 2004; 1:243-53. [PMID: 15478361 DOI: 10.3171/spi.2004.1.3.0243] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT The purpose of this study was to examine the neurological outcomes after complex lumbosacral surgery in patients undergoing multimodality neurophysiological monitoring. METHODS Sixty-one patients were consecutively enrolled in this study. These patients underwent complex intra- and extradural lumbosacral procedures with concomitant intraoperative electromyography (EMG) monitoring of the lower-limb muscles, external anal and urethral sphincters (EAS and EUS), and lower-limb somatosensory evoked potentials (SSEPs). Long-term (minimum 2-year) clinical follow-up data were obtained in all cases. Most patients were treated for spinal/spinal cord tumors (61%) or adult tethered cord syndrome (25%). Recordable lower-extremity SSEPs were reported in 54 patients (89%). New postoperative neurological deficits occurred in only three patients (4.9%), and remained persistent in only one patient (1.6%) at long-term follow-up examination. In only one of these cases was a significant decrease in SSEP amplitude detected. Spontaneous EMG activity was observed in the lower-extremity muscles and/or EAS and EUS in 51 cases (84%). Intraoperatively, EMG demonstrated activity only in the EUS in 5% of patients and only in the EAS in 28%. In seven patients (11%) spontaneous intraoperative EMG activity was observed in both the EAS and the EUS; however, in only three of these cases was EMG activity recorded in both sphincters simultaneously. In addition to spontaneously recorded EMG activity, electrically evoked EMG activity was also used as an intraoperative adjunct. A bipolar stimulating electrode was used to identify functional neural tissue before undertaking microsurgical dissection in 58 individuals (95%). In the majority of these patients, evoked EMG activity occurred either in one (33%) or in two muscles (9%) simultaneously. The presence of electrically evoked EMG activity in structures encountered during microdissection altered the plan of treatment in 24 cases (42%). CONCLUSIONS The authors conclude that the combined SSEP and EMG monitoring of lower-limb muscles, EAS, and EUS is a practical and reliable method for obtaining optimal electrophysiological feedback during complex neurosurgical procedures involving the conus medullaris and cauda equina. Analysis of the results indicates that these intraoperative adjunctive modalities positively influence decision making with regard to microsurgery and reduce the risk of perioperative neurological complications. Validation of the clinical value of these approaches, however, will require further assessment in a larger prospective cohort of patients.
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Quiñones-Hinojosa A, Gadkary CA, Gulati M, von Koch CS, Lyon R, Weinstein PR, Yingling CD. Neurophysiological monitoring for safe surgical tethered cord syndrome release in adults. ACTA ACUST UNITED AC 2004; 62:127-33; discussion 133-5. [PMID: 15261505 DOI: 10.1016/j.surneu.2003.11.025] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2002] [Accepted: 11/17/2003] [Indexed: 10/26/2022]
Abstract
BACKGROUND Release of tethered spinal cord by sectioning of the filum terminale carries a significant risk of injury to the neighboring motor and sensory nerve roots. Intraoperative neurophysiological monitoring techniques can help to minimize these adverse neurologic outcomes. METHODS We performed a retrospective review of 67 consecutive patients undergoing tethered cord release. We excluded 52 pediatric patients which limited our study to 15 adult patients treated during a four year period, including patients with a thick filum, low lying conus, myelomeningocele, filum tumor, spinal cord malformation, and/or lipoma. Clinical outcomes were determined from postoperative follow-up visits. Two patients were lost to follow up and were excluded from the clinical outcome analysis. Electrical stimulation of the filum terminale and lumbo-sacral nerve roots in conjunction with electromyogram (EMG) recording was performed intraoperatively. RESULTS The mean electrical threshold for EMG response during stimulation of the filum terminale was 37.1 volts (V), range 15 to 100 V. In comparison, the lowest threshold obtained by direct stimulation of the ventral nerve roots was a mean of 1.46 V, with a range of 0.1 to 7 V. More than 70% of the patients studied demonstrated a filum to motor root threshold ratio of 100:1 or greater. No patient developed new neurologic symptoms or signs postoperatively. Bowel and bladder function improved in 46% of patients, back pain in 39% and motor function in 31%. Eight percent reported decline in bladder control and worsening back pain postoperatively. CONCLUSIONS The often dramatic difference in the threshold of the filum terminale and adjacent motor nerve roots (100:1) helps to identify, isolate, and safely section the filum terminale. Tethered cord release using intraoperative neurophysiological monitoring is safe and in the majority of cases leads to improvement or at least, stabilization of neurologic function. Monitoring prevented intraoperative nerve root injury that might have resulted in immediate onset of new neurologic deficits caused by the surgical procedure.
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Affiliation(s)
- Alfredo Quiñones-Hinojosa
- Department of Neurological Surgery, University of California-San Francisco, 505 Parnassus Avenue, Moffitt Hospital Room M779, Box 112, San Francisco, CA 94143-0112, USA
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Dimopoulos VG, Feltes CH, Fountas KN, Kapsalakis IZ, Vogel RL, Fuhrmann B, Grigorian AA, Johnston KW, Smisson HF, Robinson JS. Does Intraoperative Electromyographic Monitoring in Lumbar Microdiscectomy Correlate with Postoperative Pain? South Med J 2004; 97:724-8. [PMID: 15352664 DOI: 10.1097/00007611-200408000-00005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Our objective was to correlate the findings of intraoperative electromyographic (EMG) monitoring with immediate postoperative pain in patients undergoing lumbar microdiscectomy. METHODS A total of 112 patients undergoing de novo lumbar microdiscectomy were prospectively randomized into a control group (n = 45) and a study group (n = 67) in which intraoperative EMG monitoring was used. Postoperative pain and postoperative narcotic consumption were recorded for each patient. RESULTS The presence or absence of EMG monitoring did not influence the level of reported pain in any anatomic area. In the monitored group, the degree of recorded nerve root irritation did not correlate with reported pain or postoperative narcotic consumption. The level of back pain was found to be significantly higher than the level of hip and calf pain (P < 0.0001). CONCLUSIONS In our study no correlation was found between intraoperative EMG findings and immediate postoperative pain.
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Affiliation(s)
- Vassilios G Dimopoulos
- Department of Neurosurgery, Medical Center of Central Georgia, Mercer University School of Medicine, Macon, GA, USA.
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Abstract
OBJECT Intraoperative neurophysiological recording techniques have found increasing use in neurosurgical practice. The development of new recording techniques feasible while the patient receives a general anesthetic have improved their practical use in a similar way to the use of digital recording, documentation, and video technology. This review intends to provide an update on the techniques used and their validity. METHODS Two principal methods are used for intraoperative neurophysiological testing during tethered cord release. Mapping identifies functional neural structures, namely nerve roots, and monitoring provides continuous information on the functional integrity of motor and sensory pathways as well as reflex circuitry. Mapping is performed mostly by using direct electrical stimulation of a structure within the surgical field and recording at a distant site, usually a muscle. Sensory mapping can also be performed with peripheral stimulation and recording within the surgical site. Monitoring of the motor system is achieved with motor evoked potentials. These are evoked by transcranial electrical stimulation and recorded from limb muscles and the external anal sphincter. The presence or absence of muscle responses are the parameters monitored. Sensory potentials evoked by tibial or pudendal nerve stimulation and recorded from the dorsal columns via an epidurally inserted electrode and/or from the scalp as cortical responses are used to access the integrity of sensory pathways. Amplitudes and latencies of these responses are then interpreted. The bulbocavernosus reflex, with stimulation of the pudendal nerve and recording of muscle responses in the external anal sphincter, is used for continuous monitoring of the reflex circuitry. Presence or absence of this response is the pertinent parameter that is monitored. CONCLUSIONS Intraoperative neurophysiology provides a wide and reliable set of techniques for intraoperative identification of neural structures and continuous monitoring of their functional integrity.
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Affiliation(s)
- Karl F Kothbauer
- Division of Pediatric Neurosurgery, Institute for Neurology and Neurosurgery, Beth Israel Medical Center, New York, New York, USA.
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Schaan M, Boszczyk B, Jaksche H, Kramer G, Günther M, Stöhrer M. Intraoperative urodynamics in spinal cord surgery: a study of feasibility. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2004; 13:39-43. [PMID: 14634852 PMCID: PMC3468037 DOI: 10.1007/s00586-003-0619-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2003] [Revised: 07/24/2003] [Accepted: 07/31/2003] [Indexed: 10/26/2022]
Abstract
Intraoperative monitoring (IOM) of bladder function in spinal cord surgery is a challenging task due to vegetative influences, multilevel innervation and numerous supraspinal modulating factors. Despite routine use of urodynamics in neurosurgery for implantation of bladder stimulators or denervation of nerve fibres in spastic reflex bladders, application of IOM in patients with spinal cord tumours or tethered-cord syndrome is not widespread. Combining urodynamics with sphincter electromyography (EMG) in IOM enables identification of bladder efferents responsible for contraction and continence. We monitored four patients with ependymoma of the Cauda equina, one patient with tethered-cord syndrome and two patients with cervical intramedullary tumours. In all patients undergoing operations of the Cauda equina, identification of bladder efferents responsible for detrusor contraction was possible. There was good correlation between preoperative bladder dysfunction, preoperative urodynamics and intraoperative pressure increase by bladder contraction or latency between stimulation and contraction. This method proved unsuitable for intramedullary tumours where no contraction of the bladder could be observed while stimulating the spinal cord. Intraoperative monitoring of urodynamics is an effective tool for identifying bladder efferents in the Cauda equina. Intraoperative conclusions on bladder dysfunction through registration of pressure increase and latency are possible.
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Affiliation(s)
- M Schaan
- Department of Neurosurgery, Unfallklinik Murnau, Prof. Küntscher Strasse 8, 82418 Murnau, Germany.
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Haro H, Komori H, Okawa A, Kawabata S, Shinomiya K. Long-Term Outcomes of Surgical Treatment for Tethered Cord Syndrome. ACTA ACUST UNITED AC 2004; 17:16-20. [PMID: 14734971 DOI: 10.1097/00024720-200402000-00005] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
SUMMARY Surgical outcomes for tethered spinal cord syndrome (TCS) associated with low-lying conus medullaris were evaluated. We investigated the long-term results of untethering the spinal cord and dural plasty in surgical patients with a wide age range. Improvement of bladder dysfunction and suppression of leg deformity progression were noted in two pediatric patients. However, severe urinary dysfunction generally remained postoperatively. Adult patients commonly showed low back or leg pain as clinical manifestations. In seven adult patients, urinary dysfunction also improved. Neurologic findings and urinary deficits showed a favorable improvement mostly in adult TCS in comparison with natal or juvenile onset of TCS. A short duration from onset to surgery and cranial movement of the conus medullaris as assessed by postoperative magnetic resonance imaging were factors indicating a favorable prognosis.
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Affiliation(s)
- Hirotaka Haro
- Department of Orthopaedic and Spinal Surgery, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan.
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Pacheco-Jacome E, Ballesteros MC, Jayakar P, Morrison G, Ragheb J, Medina LS. Occult spinal dysraphism: evidence-based diagnosis and treatment. Neuroimaging Clin N Am 2003; 13:327-34, xii. [PMID: 13677810 DOI: 10.1016/s1052-5149(03)00028-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
This article reviews the scientific evidence behind the diagnostic tools available for the appropriate workup and management of patients with occult spinal dysraphism (OSD). The diagnostic tools include the use of detailed history and physical examination, plain films, ultrasound, MR imaging, and neurophysiologic tests. In addition, the article discusses the epidemiology of the most common causes of OSD in children, which will allow physicians caring for children to develop a pretest probability of disease and make a more educated decision as to when additional diagnostic testing is required.
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Abstract
Intraoperative electromyography (EMG) provides useful diagnostic and prognostic information during spine and peripheral nerve surgeries. The basic techniques include free-running EMG, stimulus-triggered EMG, and intraoperative nerve conduction studies. These techniques can be used to monitor nerve roots during spine surgeries, the facial nerve during cerebellopontine angle surgeries, and peripheral nerves during brachial plexus exploration and repair. However, there are a number of technical limitations that can cause false-positive or false-negative results, and these must be recognized and avoided when possible. The author reviews these basic electrophysiologic techniques, how they are applied to specific surgical situations, and their limitations.
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Abstract
Lipomas of the spinal cord are among the most fascinating lesions encountered by the pediatric neurosurgeon. An understanding of spinal lipomas may, however, be difficult because the terminology used to describe the accumulations of spinal fat is confusing, inconsistently applied, and at times contradictory. An anatomical characterization of lipomas may assist in understanding these lesions. Lipomas of the spinal cord are very rare and cause symptoms related to mass effect and secondary compressive myelopathy. Lipomas of the conus medullaris (or lipomyelomeningocele) are the most common form of fatty masses in the spine and can be divided into dorsal, caudal, and transitional forms. These lesions are a manifestation of occult spinal dysraphism and a common cause of the tethered cord syndrome (TCS). The natural history of untreated lipomyelomeningocele, although incompletely understood, appears to be progressive neurological deterioration with loss of bladder control. Timely, careful surgical intervention may prevent significant neurological deterioration and progressive disability in the majority of children harboring these lesions. In surgical intervention the surgeon seeks to disrupt the connection between the fibrofatty mass and underlying cord as well as to reestablish normal anatomical planes. Several intraoperative video segments illustrating lipomyelomeningocele resection are included in this paper. Lipomas of the terminal filum (fatty filum) are truly occult and are also associated with TCS. Surgical treatment of filum lipomas carries significantly lower risk than that for lipomas of the conus medullaris. Again, the goal of surgery is to disrupt the connection between the abnormal fibrofatty tissue and the underlying spinal cord.
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Affiliation(s)
- J P Blount
- Division of Neurosurgery, University of Alabama at Birmingham, Children's Hospital of Alabama, Birmingham, Alabama 35233, USA.
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Balzer JR, Rose RD, Welch WC, Sclabassi RJ. Simultaneous somatosensory evoked potential and electromyographic recordings during lumbosacral decompression and instrumentation. Neurosurgery 1998; 42:1318-24; discussion 1324-5. [PMID: 9632191 DOI: 10.1097/00006123-199806000-00074] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
OBJECTIVE Both motor and sensory neurological deficits have been reported after decompression and instrumentation of the lumbosacral spine. In this report, we describe a simple and effective method by which sensory and motor functions can be monitored simultaneously, using somatosensory evoked potentials (SSEP), spontaneous electromyographic (EMG) activity, and compound muscle action potential monitoring. The concomitant use of these monitoring techniques allows ongoing functional evaluation of the cauda equina and spinal cord during patient positioning, surgery, wound closure, and anesthetic emergence. METHODS SSEPs were recorded continuously in response to peroneal or tibial nerve stimulation. EMG activity (both spontaneous and evoked) was recorded bilaterally from appropriate lower extremity muscle groups. All recordings (SSEP and EMG activity recordings) were obtained, stored, and reviewed simultaneously. RESULTS SSEPs and EMG activity were simultaneously recorded for 44 patients. All patients in the study underwent surgical procedures to decompress and stabilize the lumbosacral spine, using pedicle screw instrumentation. In two cases, changes in SSEPs and spontaneous EMG activity were noted and were correlated with postoperative patient complaints. CONCLUSION This report describes the concomitant use of powerful and simple tools that provide immediate, "early-warning" feedback to the surgical team concerning the sensory and motor functioning of the spinal cord and cauda equina. In addition, compound muscle action potential recording provides a tool for the identification of both levels and structures in the lumbosacral spine.
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Affiliation(s)
- J R Balzer
- Department of Neurological Surgery and Center for Clinical Neurophysiology, University of Pittsburgh Medical Center, Pennsylvania 15213, USA
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Levitt MA, Patel M, Rodriguez G, Gaylin DS, Pena A. The tethered spinal cord in patients with anorectal malformations. J Pediatr Surg 1997; 32:462-8. [PMID: 9094019 DOI: 10.1016/s0022-3468(97)90607-2] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The aims of this study were to find the prevalence of tethered cord in patients with anorectal malformations; to determine if the presence of tethered cord relates to the severity of the anorectal defect, and to certain symptoms, signs, radiologic findings, and associated anomalies; and finally to determine whether tethered cord impacted on a patient's functional prognosis and whether surgical untethering improved the patient. The authors studied 934 patients with anorectal malformations, 111 of whom had magnetic resonance imaging (MRI) of the spine. We compared patients with and without tethered cord by using parametric and nonparametric statistical tests. Tethered cord occurred in 24% of the patients. The prevalence varied according to the type of anorectal defect from 43% in the complex group to 11% in patients with rectovestibular fistula. Patients with tethered cord had a lateral sacral ratio lower than that of patients without tethered cord (0.410 versus 0.702). Tethered cord was present in 90% of patients with myelodysplasia, 60% of patients with a presacral mass, 57% of patients with sacral hemivertebrae, and 56% of patients with a single kidney. The greater number of associated anomalies a patient had, the greater the risk of having tethered cord (P < .05 for all differences). The authors noted differences between patients with and without tethered cord in the presence of voluntary bowel movements (46% versus 70%), fecal soiling (91% versus 63%), constipation (21% versus 43%), and urinary incontinence (86% versus 42%). The data indicate that patients with tethered cord have a worse functional prognosis than patients without tethered cord. However, the incontinence in our patients was also predictable based on the type of anorectal defect and the character of the sacrum irrespective of the presence of tethered cord. Eighteen patients underwent surgical untethering of the cord, and none had any significant change in bowel or urinary function postoperatively. No patient with tethered cord experienced incontinence that could be attributed to the cord defect alone. This study suggests that tethered cord occurs more frequently in patients with severe anorectal defects, sacral hypodevelopment, myelodysplasia, presacral mass, sacral hemivertebrae, or a single kidney, or in those with an anorectal defect with poor functional prognosis. At present no solid evidence supports the concept that tethered cord by itself affects the functional prognosis of patients with anorectal malformations. Also, there is no good evidence demonstrating that surgical untethering improves the prognosis.
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Affiliation(s)
- M A Levitt
- Department of Surgery, Long Island Jewish Medical Center, New Hyde Park, NY, USA
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Polo A, Zanette G, Manganotti P, Bertolasi L, De Grandis D, Rizzuto N. Spinal somatosensory evoked potentials in patients with tethered cord syndrome. Neurol Sci 1994; 21:325-30. [PMID: 7874616 DOI: 10.1017/s0317167100040907] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We studied the electrophysiological changes occurring in six patients with tethered cord syndrome. Evidence of spinal malformations was provided by magnetic resonance imaging. The functional assessment of the spinal cord was performed by analysing both spinal and cortical somatosensory evoked potentials. The evoked electrospinogram was recorded from the thoracic and lumbosacral spinous processes. The N22 lumbosacral potential was selectively affected, being rostrocaudally displaced and reduced in amplitude or even absent in patients with neurological signs indicating a segmental lower cord lesion. Inter-peak somatosensory evoked potentials latency was normal in all cases, suggesting that ascending axonal potentials in the dorsal column fibres may be synchronized. Segmental potentials of the lumbosacral response, originating from the post-synaptic activity of dorsal horn interneurons, are selectively affected in this syndrome resulting from the rostrocaudal displacement of the spinal cord due to tethering. Our findings in the clinical field are consistent with previous experimental evidence indicating a different sensitivity of the gray vs. white matter to progressive stretching.
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Affiliation(s)
- A Polo
- Dipartimento di Scienze Neurologiche E Della Visione, Universita Degli Studi di Veron, Italy
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Kothbauer K, Schmid UD, Seiler RW, Eisner W. Intraoperative motor and sensory monitoring of the cauda equina. Neurosurgery 1994; 34:702-7; discussion 707. [PMID: 8008170 DOI: 10.1227/00006123-199404000-00020] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
A set of standard techniques to monitor the motor and sensory function of the cauda equina is proposed for surgery in the lumbosacral spinal canal for the release of a tethered cord or the removal of a neoplasm. Continuous loudspeaker-controlled recording of electromyographic activity in four leg muscles of both sides supplied the surgeon with immediate feedback on injury to any of the motor roots from the second lumbar to the fourth sacral segment. Continuous recording of tibial nerve somatosensory evoked potentials yielded information about the functional state of parts of the lumbosacral sensory pathways. Motor roots could be identified by electrical stimulation in the operating field with bipolar stimulation forceps and recording of compound muscle action potentials from the leg muscles. Sensory nerve roots could be identified by nerve root somatosensory evoked potentials recorded from the scalp after the electrical stimulation of the exposed nerve. This set-up is a combination of previously developed monitoring techniques and provides the surgeon with functional information: 1) continuous feedback on the state of the endangered motor and sensory function of the cauda equina; and 2) rapid anatomical identification of nerve roots and their distinction from fibrous or neoplastic structures.
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Affiliation(s)
- K Kothbauer
- Department of Neurosurgery, Inselspital, University of Bern, Switzerland
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