Spinal Surgery With Electrically Evoked Potential Monitoring and Monopolar Electrocautery: Is Prior Removal of a Cochlear Implant Necessary?

Development of Consensus-Based Best Practice Guidelines for the Perioperative and Postoperative Care of Pediatric Patients With Spinal Deformity and Programmable Implanted Devices

STUDY DESIGN

Modified Delphi consensus study.

OBJECTIVE

To develop consensus-based best practices for the care of pediatric patients who have implanted programmable devices (IPDs) and require spinal deformity surgery.

SUMMARY OF BACKGROUND DATA

Implanted programmable devices (IPDs) are often present in patients with neuromuscular or syndromic scoliosis who require spine surgery. Guidelines for monitoring and interrogating these devices during the perioperative period are not available.

METHODS

A panel was assembled consisting of 25 experts (i.e., spinal deformity surgeons, neurosurgeons, neuroelectrophysiologists, cardiologists, and otolaryngologists). Initial postulates were based on a literature review and results from a prior survey. Postulates addressed the following IPDs: vagal nerve stimulators (VNS), programmable ventriculoperitoneal shunts (VPS), intrathecal baclofen pumps (ITBP), cardiac pacemakers and implantable cardioverter-defibrillators (ICD), deep brain stimulators (DBS), and cochlear implants. Cardiologist and otolaryngologist participants responded only to postulates on cardiac pacemakers or cochlear implants, respectively. Consensus was defined as ≥80% agreement, items that did not reach consensus were revised and included in subsequent rounds. A total of 3 survey rounds and 1 virtual meeting were conducted.

RESULTS

Consensus was reached on 39 total postulates across 6 IPD types. Postulates addressed general spine surgery considerations, the use of intraoperative monitoring and cautery, the use of magnetically controlled growing rods (MCGRs), and the use of an external remote controller to lengthen MCGRs. Across IPD types, consensus for the final postulates ranged from 94.4% to 100%. Overall, experts agreed that MCGRs can be surgically inserted and lengthened in patients with a variety of IPDs and provided guidance for the use of intraoperative monitoring and cautery, which varied between IPD types.

CONCLUSION

Spinal deformity correction surgery often benefits from the use of intraoperative monitoring, monopolar and bipolar cautery, and MCGRs. The final postulates from this study can inform the perioperative and postoperative practices of spinal deformity surgeons who treat patients with both scoliosis and IPDs.

LEVEL OF EVIDENCE

V-Expert opinion.

Intraoperative Monitoring of Scoliosis Surgery in Young Patients

SUMMARY

Intraoperative neurophysiologic monitoring has added substantially to the safety of spinal deformity surgery correction since its introduction over four decades ago. Monitoring routinely includes both somatosensory evoked potentials and motor evoked potentials. Either modality alone will detect almost all instances of spinal cord injury during deformity correction. The combined use of the two modalities provides complementary information, can permit more rapidly identification of problems, and enhances safety though parallel redundancy should one modality fail. Both techniques are well established and continue to be refined. Although there is room for provider preference, proper monitoring requires attention to technical detail, understanding of the underlying physiology, and familiarity with effects of commonly used anesthetic agents.

Risk of Monopolar Electrosurgery in Cochlear Implant Recipients is Nominal: Evidence to Guide Clinical Practice

OBJECTIVE

Comprehensively assess the prevalence of monopolar electrosurgery-related device complications among cochlear implant (CI) recipients.

STUDY DESIGN

Multifaceted retrospective review and survey.

SETTING

Tertiary medical center.

METHODS

Multifaceted approach including: (i) review of the current literature; (ii) historical review of institutional data from an academic, tertiary CI center; (iii) review of industry data provided by 3 Food and Drug Administration-approved CI manufacturers; and (iv) survey of high-volume CI centers.

RESULTS

Literature review identified 9 human studies, detailing 84 devices with 199 episodes of device-cautery exposure. From studies reporting on patients records, no implant showed evidence of damage after exposure. One cadaveric study using dental cautery reported 1 episode of device damage. Review of institutional records did not identify any CI damage in 84 instances of exposure. Data from the 3 major implant manufacturers showed a single report of damage that could be reasonably linked to monopolar electrosurgery, out of a possible 689,426 CIs. Last, a survey of 8 high-volume CI centers did not identify any adverse events associated with monopolar cautery.

CONCLUSION

These data estimate the risk of adverse device-related events or tissue injury to be extraordinarily low. Short of operating in immediate proximity to the CI (ie, the ipsilateral temporoparietal scalp), these data indicate that monopolar electrosurgery can be used in the body and the head-and-neck of CI recipients with nominal risk. These findings may guide decision-making in cases that are optimally or preferably performed with monopolar electrocautery and can be used to counsel CI patients following inadvertent exposures.

Use of monopolar cautery in patient with a vagal nerve stimulator during neuromuscular scoliosis surgery

It is a historic and common practice while performing spine surgery on patients with a VNS has been to have the patient's neurologist turn off the VNS generator in the pre-operative anesthetic care unit and to use bipolar rather than monopolar electrocautery. Here we report a case of a 16-year-old male patient with cerebral palsy and refractory epilepsy managed with an implanted VNS who had scoliosis surgery (and subsequent hip surgery) conducted with the use of monopolar cautery. Although VNS manufacturer guidelines suggest that monopolar cautery should be avoided, perioperative care providers should consider its selective use in high-risk instances (with greater risks of morbidity and mortality due to blood loss which outweigh the risk of surgical re-insertion of a VNS) such as cardiac or major orthopedic surgery. Considering the number of patients with VNS devices presenting for major orthopedic surgery is increasing, it is important to have an approach and strategy for perioperative management of VNS devices.

Monopolar Cautery Use in Pediatric Cochlear Implant Users

OBJECTIVES

To determine the incidence and impact of monopolar cautery use in a cohort of pediatric cochlear implant (CI) users.

STUDY DESIGN

Case series from a retrospective chart review and a systematic review of the literature.

SETTING

Tertiary academic referral center.

METHODS

CI patient charts from 2012 to 2021 were reviewed from a single pediatric hospital system to determine if monopolar cautery was used during a subsequent surgical procedure. In addition, a systematic review of the literature was performed to identify additional, relevant patients. Postoperative CI function was the primary outcome measure.

RESULTS

In total, 190 patients underwent a surgical procedure following cochlear implantation in a single pediatric hospital system. Fifteen patients (7.9%) and 17 distinct surgical procedures were identified in which monopolar cautery was used. Seven of these 17 cases (41.2%) involved the head and neck, and 10 were performed below the clavicles. No patients experienced a device failure or a decline in CI performance following surgery. A systematic review identified an additional 4 patients who underwent a surgery that used monopolar cautery following cochlear implantation, and no change in CI function was identified.

CONCLUSIONS

The present study adds additional support to the notion that monopolar cautery does not necessarily injure CI functionality. While the most risk adverse strategy when planning a surgical procedure for a CI patient is to avoid monopolar cautery use altogether, the use of cautery should not immediately be associated with implant dysfunction.

Does the presence of programmable implanted devices in patients with early onset scoliosis alter typical operative and postoperative practices? A survey of spine surgeons

PURPOSE

Operative and postoperative management of early onset scoliosis (EOS) patients with programmable implanted devices has not been well characterized in the literature. The aim of this study was to describe current practices for pediatric spine surgeons who operate on patients with these devices.

METHODS

An electronic survey was distributed to 167 pediatric spine surgeons between January and March of 2021. The survey queried participants on operative and postoperative management of patients with the following implanted devices: vagal nerve stimulators, ventriculoperitoneal shunts, intrathecal baclofen pumps, pacemakers, and cochlear implants. Descriptive statistics were used to assess survey data.

RESULTS

Fifty-three respondents (31.7% response rate) with a mean 16.5 (SD 12.0) years in practice completed the survey. Depending on the type of device present, surgeons report changing their operative plan anywhere from 28.6 to 60.1% of the time when inserting magnetically controlled growing rods. Most respondents reported performing transcranial motor evoked potentials (80.0-98.0%) and monopolar cautery (70.0-92.9%) across implanted devices. Only 10% (n = 5) of surgeons reported complications related to operative and/or postoperative management of these patients. No complications were related to cautery, neuromonitoring, or surgical placement of MCGRs.

CONCLUSIONS

This study demonstrates variation in operative and postoperative management of these patients with various programmable implanted devices. Much of this inconsistency in practice is likely due to decades old case reports, constantly changing device manufacturer recommendations, and/or published simulation studies. Reported heterogeneity in management across surgeons necessitates development of published guidelines regarding proper operative and postoperative management of patients with EOS and implanted devices.

Neurophysiological Intraoperative Monitoring in Patients with Cochlear Implant Undergoing Posterior Spinal Fusion: A Case Report

CASE

Transcranial electric stimulation motor-evoked potentials (tcMEPs) are the most sensitive technique in multimodality intraoperative neuromonitoring (IONM) for posterior spinal fusion (PSF). The presence of a cochlear implant (CI) is considered a contraindication to IONM because of theoretical risk of implant device and local tissue damage from voltages induced by tcMEPs. We present the case of a 10-year-old girl with CI who underwent successful PSF with tcMEP and monopolar electrocautery (MoEC) without perioperative complications or CI damage.

CONCLUSION

With proper precautions, such as MoEC usage at a minimal voltage, motor-evoked potential monitoring can be safely performed in pediatric patients with CI undergoing PSF.