J Neurol Surg A Cent Eur Neurosurg 2015; 76(04): 303-308
DOI: 10.1055/s-0034-1373664
Original Article
Georg Thieme Verlag KG Stuttgart · New York

Percutaneous Pedicle Screw Accuracy with Dynamic Electromyography: The Early Experience of a Traditionally Open Spine Surgeon

Gregory M. Malham
1   Department of Neuroscience Institute, Epworth Hospital, Richmond, Melbourne, Victoria, Australia
Ben Goss
2   Department of Clinical Affairs, NuVasive Australia & NZ Pty Ltd, Victoria, Australia
Carl Blecher
3   Department of Primary Healthcare Imaging, Epworth Hospital, Victoria, Australia
› Author Affiliations
Further Information

Publication History

20 October 2013

16 January 2014

Publication Date:
27 April 2015 (online)


Background and Study Aims The learning curve associated with the adoption of minimally invasive surgery techniques has limited its adoption by many traditionally open surgeons. The use of dynamic electromyography (EMG) to guide the placement of percutaneous pedicle screws (PS) can lessen the learning curve by providing real-time feedback on neural proximity relative to the screw. This study aimed to investigate the safety and accuracy of a single surgeon's experience transitioning from open pedicle screws (OS) to PS using intraoperative fluoroscopy and dynamic EMG.

Materials and Methods Forty consecutive patients were treated with EMG and fluoroscopy-guided PS placement by a single surgeon and followed through a prospective registry. This was cross-referenced with a cohort of 53 consecutive patients treated with OS in 2011. Computed tomography was used to check the screw position 1 day after surgery. A misplaced pedicle screw was defined as a breach of the pedicle wall. The accuracy of PS placement in association with dynamic EMG was compared with that of OS.

Results A total of 204 PS were inserted in the study cohort with 97.5% accuracy. Five (2.5%) were misplaced (three medial and two lateral). All three medial screws displayed a caution message (yellow: 8mA) on insertion. No screw caused visceral or neurologic complications postoperatively, and none required revision. In the OS cohort, 254 screws were placed with 94.9% accuracy, 13 (5.1%) were misplaced (8 medial, 3 lateral, and 2 superior), and 3 (1.2%) required revision.

Conclusions Dynamic EMG combined with intraoperative fluoroscopy and advanced instrumentation provides a safe, real-time, and accurate method for PS placement.

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