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

Abstract

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.

Keywords

electromyography - minimally invasive spine surgery - pedicle screw accuracy - percutaneous screw

• References

• 1 Jaikumar S, Kim DH, Kam AC. History of minimally invasive spine surgery. Neurosurgery 2002; 51 (5) (Suppl): S1-S14
• 2 Khoo LT, Beisse R, Potulski M. Thoracoscopic-assisted treatment of thoracic and lumbar fractures: a series of 371 consecutive cases. Neurosurgery 2002; 51 (5 Suppl): 104-117
• 3 Epstein NE. How often is minimally invasive minimally effective: what are the complication rates for minimally invasive surgery?. Surg Neurol 2008; 70 (4) 386-388; discussion 389
• 4 Isaacs RE, Hyde J, Goodrich JA, Rodgers WB, Phillips FM. A prospective, nonrandomized, multicenter evaluation of extreme lateral interbody fusion for the treatment of adult degenerative scoliosis: perioperative outcomes and complications. Spine 2010; 35 (26) (Suppl): S322-S330
• 5 Oliveira L, Marchi L, Coutinho E, Pimenta L. A radiographic assessment of the ability of the extreme lateral interbody fusion procedure to indirectly decompress the neural elements. Spine 2010; 35 (26) (Suppl): S331-S337
• 6 Kepler CK, Sharma AK, Huang RC , et al. Indirect foraminal decompression after lateral transpsoas interbody fusion. J Neurosurg Spine 2012; 16 (4) 329-333
• 7 Ozkan N, Sandalcioglu IE, Petr O , et al. Minimally invasive transpedicular dorsal stabilization of the thoracolumbar and lumbar spine using the minimal access non-traumatic insertion system (MANTIS): preliminary clinical results in 52 patients. J Neurol Surg A Cent Eur Neurosurg 2012; 73 (6) 369-376
• 8 Kosmopoulos V, Schizas C. Pedicle screw placement accuracy: a meta-analysis. Spine 2007; 32 (3) E111-E120
• 9 Holly LT, Foley KT. Intraoperative spinal navigation. Spine 2003; 28 (15) (Suppl): S54-S61
• 10 Costa F, Cardia A, Ortolina A, Fabio G, Zerbi A, Fornari M. Spinal navigation: standard preoperative versus intraoperative computed tomography data set acquisition for computer-guidance system: radiological and clinical study in 100 consecutive patients. Spine 2011; 36 (24) 2094-2098
• 11 Gelalis ID, Paschos NK, Pakos EE , et al. Accuracy of pedicle screw placement: a systematic review of prospective in vivo studies comparing free hand, fluoroscopy guidance and navigation techniques. Eur Spine J 2012; 21 (2) 247-255
• 12 Uribe JS, Vale FL, Dakwar E. Electromyographic monitoring and its anatomical implications in minimally invasive spine surgery. Spine 2010; 35 (26) (Suppl): S368-S374
• 13 Ozgur BM, Berta S, Khiatani V, Taylor WR. Automated intraoperative EMG testing during percutaneous pedicle screw placement. Spine J 2006; 6 (6) 708-713
• 14 Miles P, Martinelli S, Arambula J , inventors. System and methods for performing dynamic pedicle integrity assessments. US patent 7,757,308 B2. 2010
• 15 Mobbs RJ, Sivabalan P, Li J. Technique, challenges and indications for percutaneous pedicle screw fixation. J Clin Neurosci 2011; 18 (6) 741-749
• 16 Calancie B, Madsen P, Lebwohl N. Stimulus-evoked EMG monitoring during transpedicular lumbosacral spine instrumentation. Initial clinical results. Spine 1994; 19 (24) 2780-2786
• 17 Wood MJ, Mannion RJ. Improving accuracy and reducing radiation exposure in minimally invasive lumbar interbody fusion. J Neurosurg Spine 2010; 12 (5) 533-539
• 18 Laine T, Schlenzka D, Mäkitalo K, Tallroth K, Nolte LP, Visarius H. Improved accuracy of pedicle screw insertion with computer-assisted surgery. A prospective clinical trial of 30 patients. Spine 1997; 22 (11) 1254-1258
• 19 Laine T, Lund T, Ylikoski M, Lohikoski J, Schlenzka D. Accuracy of pedicle screw insertion with and without computer assistance: a randomised controlled clinical study in 100 consecutive patients. Eur Spine J 2000; 9 (3) 235-240
• 20 Wood M, Mannion R. A comparison of CT-based navigation techniques for minimally invasive lumbar pedicle screw placement. J Spinal Disord Tech 2011; 24 (1) E1-E5