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Nakamura et al. Mini-invasive Surg 2019;3:29 Mini-invasive Surgery
DOI: 10.20517/2574-1225.2019.28

Original Article Open Access

The difference of intraoperative free-run
electromyography monitoring between

percutaneous endoscopic lumbar discectomy via a
transforaminal and via an interlaminal

Jun-Ichiro Nakamura, Tomoyuki Setoue, Jun Hara

Orthopedic surgery, Kawasaki-saiwai hospital, Kawasaki city, Kanagawa-ken 212-0014, Japan.

Correspondence to: Dr. Jun-Ichiro Nakamura, Orthopedic surgery, Kawasaki-saiwai hospital, 31-27 Ohmiya-cho, Saiwai-ku,
Kawasaki city, Kanagawa-ken 212-0014, Japan. E-mail: nakajun16@yahoo.co.jp

How to cite this article: Nakamura JI, Setoue T, Hara J. The difference of intraoperative free-run electromyography monitoring
between percutaneous endoscopic lumbar discectomy via a transforaminal and via an interlaminal. Mini-invasive Surg
2019;3:29. http://dx.doi.org/10.20517/2574-1225.2019.28

Received: 26 Aug 2019 First Decision: 26 Sep 2019 Revised: 2 Oct 2019 Accepted: 10 Oct 2019 Published: 15 Oct 2019
Science Editor: Giulio Belli Copy Editor: Cai-Hong Wang Production Editor: Tian Zhang

Abstract
Aim: Transforaminal percutaneous endoscopic lumbar discectomy (TF-PELD) is usually performed under local
anesthesia because the patient should be conscious to prevent nerve root injury. However, some patients cannot tolerate
intraoperative pain and require intravenous analgesia, or must be converted to surgery under general anesthesia (GA). If
PELD under GA can be performed safely, it is more convenient and comfortable for both the patient and surgeon.

Methods: A total of 49 cases (mean age, 53 years) were examined. PELD was performed under GA with free-run
electromyography (f-EMG) monitoring. Clinical outcomes were assessed according to the visual analogue scale score
(VAS) and the Oswestry disability index (ODI). All patients were monitored with f-EMG.

Results: VAS decreased from 7.7 to 1.1 and ODI from 62.3% to 20.5%. A true-positive was observed in one of 27 TF-
PELD cases. Care during the procedure is necessary to avoid the risk of severe neurological injury. A false-negative was
observed in one of 22 interlaminar (IL)-PELD cases. This patient complained of aggravated numbness for 6 months after
surgery. False-positives were recorded in 2 cases of IL-PELD with a train wave just after removal of the herniated discs.

Conclusion: F-EMG monitoring during PELD under GA was useful to identify nerve root damage. TF-PELD under GA
requires f-EMG to ensure safety. On the contrary, IL-PELD does not necessitate f-EMG.

Keywords: Free-run electromyography, general anesthesia, iatrogenic nerve injury, percutaneous endoscopic lumbar
discectomy

© The Author(s) 2019. Open Access This article is licensed under a Creative Commons Attribution 4.0
International License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use,
sharing, adaptation, distribution and reproduction in any medium or format, for any purpose, even commercially, as long
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