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Risk factors for false positive transcranial motor evoked potential monitoring alerts during surgical treatment of cervical myelopathy.
Spine (Phila Pa 1976). 2007 Dec 15; 32(26):3041-6.S

Abstract

STUDY DESIGN

Retrospective consecutive series review.

OBJECTIVE

To examine performance of transcranial motor-evoked potential (TcMEP) monitoring in patients undergoing surgery for cervical myelopathy and potential risk factors for false positive alerts.

SUMMARY OF BACKGROUND DATA

Although use of TcMEP monitoring has been increasing and has been specifically recommended in patients with cervical myelopathy, rates and risk factors for false positive alerts have not been established.

METHODS

Intraoperative neuromonitoring data for 52 consecutive patients undergoing surgery for cervical myelopathy were reviewed. All major TcMEP alerts were identified. Comprehensive demographic and clinical data, preoperative imaging studies, operative, and anesthesia records were reviewed.

RESULTS

Six of 52 patients (12%) experienced a major TcMEP alert consisting of sustained >80% loss of amplitude. There were no somatosensory-evoked potential (SSEP)-related alerts. In 2 cases, an intraoperative wake-up test was negative and in 3 cases, surgery was completed without a wake-up test and without recovery of TcMEP signals. No new postoperative neurologic deficits were observed in these patients. One patient with new postoperative weakness was correctly predicted by loss of TcMEP signals. No new deficit was observed in the remaining 46 patients. Statistical analysis revealed significantly higher body mass index (28.8 vs. 35.0; P = 0.032) and length of surgery (191 vs. 283 minutes; P = 0.019) in patients with false positive alerts.

CONCLUSION

In this series of cervical myelopathy patients, sensitivity and specificity of TcMEP for detection of clinically significant intraoperative cord injury were 100% and 90%, respectively. Sensitivity and specificity of SSEP were 0% and 100%, respectively. The positive predictive value of a TcMEP alert was 17%. Possible risk factors for false positive TcMEP alerts include obesity and increased length of surgery. This study supports superior sensitivity of TcMEP compared with SSEP monitoring but identifies a relatively high false positive rate even in a selected high-risk cervical myelopathy population when this modality is applied in practice.

Authors+Show Affiliations

Department of Orthopaedic Surgery, Tufts University Medical School, New England Baptist Hospital, Boston, MA, USA. dhkim@caregroup.harvard.eduNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

18091499

Citation

Kim, David H., et al. "Risk Factors for False Positive Transcranial Motor Evoked Potential Monitoring Alerts During Surgical Treatment of Cervical Myelopathy." Spine, vol. 32, no. 26, 2007, pp. 3041-6.
Kim DH, Zaremski J, Kwon B, et al. Risk factors for false positive transcranial motor evoked potential monitoring alerts during surgical treatment of cervical myelopathy. Spine. 2007;32(26):3041-6.
Kim, D. H., Zaremski, J., Kwon, B., Jenis, L., Woodard, E., Bode, R., & Banco, R. J. (2007). Risk factors for false positive transcranial motor evoked potential monitoring alerts during surgical treatment of cervical myelopathy. Spine, 32(26), 3041-6.
Kim DH, et al. Risk Factors for False Positive Transcranial Motor Evoked Potential Monitoring Alerts During Surgical Treatment of Cervical Myelopathy. Spine. 2007 Dec 15;32(26):3041-6. PubMed PMID: 18091499.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Risk factors for false positive transcranial motor evoked potential monitoring alerts during surgical treatment of cervical myelopathy. AU - Kim,David H, AU - Zaremski,Jason, AU - Kwon,Brian, AU - Jenis,Louis, AU - Woodard,Eric, AU - Bode,Robert, AU - Banco,Robert J, PY - 2007/12/20/pubmed PY - 2008/3/4/medline PY - 2007/12/20/entrez SP - 3041 EP - 6 JF - Spine JO - Spine VL - 32 IS - 26 N2 - STUDY DESIGN: Retrospective consecutive series review. OBJECTIVE: To examine performance of transcranial motor-evoked potential (TcMEP) monitoring in patients undergoing surgery for cervical myelopathy and potential risk factors for false positive alerts. SUMMARY OF BACKGROUND DATA: Although use of TcMEP monitoring has been increasing and has been specifically recommended in patients with cervical myelopathy, rates and risk factors for false positive alerts have not been established. METHODS: Intraoperative neuromonitoring data for 52 consecutive patients undergoing surgery for cervical myelopathy were reviewed. All major TcMEP alerts were identified. Comprehensive demographic and clinical data, preoperative imaging studies, operative, and anesthesia records were reviewed. RESULTS: Six of 52 patients (12%) experienced a major TcMEP alert consisting of sustained >80% loss of amplitude. There were no somatosensory-evoked potential (SSEP)-related alerts. In 2 cases, an intraoperative wake-up test was negative and in 3 cases, surgery was completed without a wake-up test and without recovery of TcMEP signals. No new postoperative neurologic deficits were observed in these patients. One patient with new postoperative weakness was correctly predicted by loss of TcMEP signals. No new deficit was observed in the remaining 46 patients. Statistical analysis revealed significantly higher body mass index (28.8 vs. 35.0; P = 0.032) and length of surgery (191 vs. 283 minutes; P = 0.019) in patients with false positive alerts. CONCLUSION: In this series of cervical myelopathy patients, sensitivity and specificity of TcMEP for detection of clinically significant intraoperative cord injury were 100% and 90%, respectively. Sensitivity and specificity of SSEP were 0% and 100%, respectively. The positive predictive value of a TcMEP alert was 17%. Possible risk factors for false positive TcMEP alerts include obesity and increased length of surgery. This study supports superior sensitivity of TcMEP compared with SSEP monitoring but identifies a relatively high false positive rate even in a selected high-risk cervical myelopathy population when this modality is applied in practice. SN - 1528-1159 UR - https://www.unboundmedicine.com/medline/citation/18091499/Risk_factors_for_false_positive_transcranial_motor_evoked_potential_monitoring_alerts_during_surgical_treatment_of_cervical_myelopathy_ L2 - http://dx.doi.org/10.1097/BRS.0b013e31815d0072 DB - PRIME DP - Unbound Medicine ER -