Anesthetic Considerations and Perioperative Management of Spinal Cord Stimulators: Literature Review and Initial Recommendations.

BACKGROUND

Patients with implanted spinal cord stimulators (SCS) present to the anesthesia care team for management at many different points along the care continuum. Currently, the literature is sparse on the perioperative management. What is available is confusing; monopolar electrocautery is contraindicated but often used, full body magnetic resonance imaging (MRI) is safe with particular systems but with other manufactures only head and specific extremities exams are safe. Moreover, there are anesthetizing locations outside of the operating room where implanted SCS can interact with surrounding medical equipment and pose significant risk to patient and device.

OBJECTIVES

The objective of this review is to present relevant known literature about the safe management of SCS in the perioperative period and to begin to develop recommendations.

STUDY DESIGN

A review of current literature and each manufacturers' labeling was performed to assess risk of interference and patient harm between SCS and technology used in and around typical anesthetizing locations.

METHODS

A systematic search of the literature was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement. A computerized search was conducted for English articles in print up to April 2016 via PubMed www.ncbi.nlm.nih.gov/pubmed; EMBASE www.embase.com; and Cochrane Library www.thecochranelibrary.com. Search terms included "spinal cord stimulator AND MRI," "spinal cord stimulator AND ECG," "spinal cord stimulator AND implanted cardiac device," "spinal cord stimulator AND electrocautery," and "spinal cord stimulator AND obstetrics." In addition, a search of Google and Google Scholar was performed. Websites of SCS manufactures were reviewed.

RESULTS

Generalized recommendations include turning the amplitude of the SCS to the lowest possible SETTING and turning off prior to any procedure. Monopolar electrocautery is contraindicated but is still often utilized; placing grounding pads as far away from the device can reduce the risk to device and patient. Bipolar cautery is favored. Implanted cardiac devices can interfere with SCS, but risks can be minimized. Neuraxial anesthesia can be attempted in a patient with implanted SCS, provided the device is not in the expected path. MRI labeling differences present the biggest difference among SCS manufactures. Medtronic's SureScan SCS, Boston Scientific's Precision system, St. Jude's Proclaim, and Stimwave's Freedome SCS are full body MRI compatible under specific conditions, while other manufacturers have labeling that restricts exams of the trunk and certain extremities.

LIMITATIONS

This review was intended to be a comprehensive, cumulative review of recommendations for perioperative SCS management; however, the limitations of a review of this nature is the complete reliance on previously published research and the availability of these studies using the methods outlined.

CONCLUSIONS

SCS is being used earlier in the treatment algorithm for patients with chronic pain. The anesthesia care team needs working knowledge of where the device resides in the neuraxial space and what risks different medical technologies pose to the patient and device. This understanding will lead to appropriate perioperative management which can reduce risk and improve patient outcomes.