Table 1 Incidence of intraoperative neuromonitoring use in spine surgery
EMG, electromyography; SSEPs, somatosensory-evoked potentials; MEPs, motor-evoked potentials; ACDF/TDR, anterior cervical diskectomy and fusion/total disk replacement
Source: Goss et al., “Utilization of Intraoperative Neuromonitoring during Spine Surgeries and Associated Conflicts of Interest.”


Published 9/2/2021
Rebecca Araujo

Use of Intraoperative Neuromonitoring during Spine Surgery Varies Widely

A survey of spine surgeons found that use of intraoperative neuromonitoring (IONM) during spine surgery varied depending on the surgical indication. The respondents also noted frequent out-of-network billing and high costs associated with IONM. The presenting author is Madison L. Goss, MD, a general surgery resident at the University of Pittsburgh Medical Center Mercy.

IONM is a technique in which the nervous system is continuously monitored during surgery for potential risk of surgical injury. According to the authors, “IONM has become more commonplace, yet there is no standard, ‘one-size-fits-all’ technique used for all spine surgeries.” However, they noted that some courts have definitively declared IONM to be a legal standard of care. “Conversely,” they wrote, “given the controversial cost-benefit analysis, many payers consider IONM ‘not medically necessary,’ forcing a surgeon’s hand into under- or over-utilizing IONM independent of its clinical value.”

To explore surgeons’ patterns of and rational for IOMN use, the investigators administered a three-part online survey to 193 spine surgeons, 60 percent of whom were neurosurgeons.

Respondents reported their use of different IONM modalities during 20 surgical scenarios, then ranked the importance of several reasons for using IONM. Surgeons recorded whether they used electromyography (EMG), somatosensory-evoked potentials (SSEPs), motor-evoked potentials (MEPs), or a combination thereof.

The survey also included questions on conflicts of interest, out-of-network billing, and costs associated with IONM use.

“The addition of IONM can add significant cost, causing its value to be questioned,” the authors wrote. “The fees for similar IONM services can vary significantly and be billed independent of their hospital charges.”

The full analysis of IONM use across spinal surgical scenarios is presented in Table 1. Among the cervical procedures listed, surgeons used IONM more frequently during anterior cervical diskectomy and fusion (ACDF)/total disk replacement (TDR) for myelopathy compared to ACDF/TDR for radiculopathy (76 percent versus 47 percent). IONM was used in 87 percent of cases of deformity. In contrast, monitoring was used in 36 percent of laminoforaminotomy cases for radiculopathy.

Among the thoracic surgery scenarios, IONM was used in 73 percent of laminectomies for myelopathy and 90 percent of cases of thoracolumbar deformity with or without osteotomy. For lumbar procedures, IONM was used in 17 percent of laminectomies; however, monitoring was used in 54 percent of cases of laminectomies with posterior instrumental fusion. Eighty-one percent of lateral lumbar interbody fusions included IONM monitoring.

Neuromonitoring was used frequently during the treatment of traumatic spinal injuries. For cord-level trauma, surgeons performing cervical surgery were more likely to use monitoring for patients with presence of cord compression and/or neurological symptoms. IONM was used in 63 percent of cervical trauma cases without cord compression and neurological symptoms, compared to 79 percent of cases with cord compression and 81 percent of cases with neurological symptoms. Similarly, IONM was also used frequently in cases of thoracic trauma surgery with cord compression or neurological symptoms (80 percent and 82 percent).

In cases of myelopathy, deformity, cord compression, and neurological symptoms in which surgeons used SSEPs, 11 percent of surgeons did not use concurrent MEPs.

The importance of each reason for monitoring was rated from 0 to 10. Surgeons reported “medicolegal” reasons as the most important (mean score, 7.4). “Surgeon reassurance” (6.2; P <0.0001) and “belief it affects patient outcomes” (5.2;> P = 0.004) had the second- and third-highest importance.

Use of IONM techniques in scenarios not routinely covered by payers ranged from 16 percent to 52 percent. Twenty-seven percent of respondents reported awareness of conflicts of interest associated with IONM within their geographical region. The most common conflict of interest reported was between surgeons and monitoring companies. According to the authors, most respondents “felt IONM companies were frequently billing out-of-network.” Of surgeons who reported awareness of costs, 28 percent cited a cost of $5,000 or more.

“Although there is increasing use of IONM, this has not translated to an absolute requirement for every spine surgery,” the authors wrote in their summary. “Surgeons are faced with opposing influences of the medicolegal system and insurance payers. Future guidelines on using IONM should not be absolute, but rather should consider the risks of each procedure, along with how patients and surgeons value these risks, in addition to the costs of not using IONM.”

The authors wrote that these findings “should help to serve as a guide to surgeons, payers, and courts as contemporary, common practices for the use of IONM during spinal surgical scenarios.”

The study will be on display as P0867 today and tomorrow in Academy Hall, Sails Pavilion, from 7 a.m. to 5 p.m.

Dr. Goss’ coauthor of “Utilization of Intraoperative Neuromonitoring during Spine Surgeries and Associated Conflicts of Interest” is Jesse E. Bible, MD.

Rebecca Araujo is the associate editor of AAOS Now.