Is intraoperative neurophysiological monitoring (IONM) medically necessary for a patient undergoing cervical spinal surgery with diagnoses of spinal stenosis and cervical spondylosis?

Medical Necessity Determination: IONM Not Supported for This Case

Intraoperative neurophysiological monitoring (IONM) is NOT medically necessary for this patient undergoing C4-7 ACDF for cervical radiculopathy and spondylosis without documented myelopathy, tumor, trauma, significant deformity, or severe cord compression. The Aetna policy explicitly states that IONM is considered insufficient evidence or unproven "during cervical spine surgery in the absence of tumor or intramedullary lesion, traumatic injury, significant deformity or instability, ossification of the posterior longitudinal ligament, or severe cord compression" 1.

Critical Documentation Deficiencies

The medical record fails to establish medical necessity based on the following gaps:

• No documented myelopathy: The diagnosis codes list only spinal stenosis (M48.02) and deforming dorsopathy (M43.8X2), with clinical documentation describing cervical radiculopathy but no evidence of myelopathy 1
• Imaging does not support severe cord compression: The MRI from 5/17/2025 states "No definite intramedullary abnormal signal is identified" and describes multilevel spondylosis "most severe at C4-5 and C5-6" without documenting severe cord compression 1
• Clinical presentation is radiculopathy, not myelopathy: The patient presents with right upper extremity numbness and pain, with improvement of symptoms—classic radiculopathy rather than spinal cord dysfunction 1

Evidence-Based Analysis

Guidelines Demonstrate Limited Value in This Population

The Journal of Neurosurgery guidelines (2009) provide Class II evidence that IONM has not been shown to improve outcomes in routine anterior cervical procedures for radiculopathy 2:

• Smith et al. reviewed 1,039 patients undergoing ACDF for radiculopathy with approximately half monitored by SSEP—there were 6 alerts in the monitored group (5 from hypotension, 1 from retractor position), but none of these patients developed new postoperative deficits 2
• One patient in the unmonitored group developed central cord syndrome, demonstrating that monitoring did not prevent the only neurological complication in this large series 2
• This provides Class II evidence that SSEP monitoring does not reduce neurological injury rates in nonmyelopathic cervical radiculopathy patients 1

High False-Positive Rates Create Clinical Harm

The evidence reveals concerning rates of false-positive alerts that can lead to inappropriate surgical decisions 2:

• In a series of 1,445 patients undergoing ventral cervical surgery, 16% of operations for cervical spondylotic myelopathy (CSM) had major alerts, yet only 2 patients suffered actual neurological injury 2
• Eight patients had surgery aborted due to persistent EP abnormalities despite intervention, yet none developed new neurological deficits—representing unnecessary surgical abandonment 2
• This demonstrates that monitoring "should not be relied on to provide the sole impetus for substantial alterations in the surgical plan" (Class III evidence) 2

Specific Modality Analysis

CPT 95938 (SSEP): Not justified 1

• SSEP monitoring only assesses posterior column function and cannot detect anterior cord injury where motor pathways reside 3
• Multiple studies show SSEP improvements are not necessary for clinical recovery—20 of 21 patients without SSEP improvement still recovered after decompression 2

CPT 95955 (EEG): Explicitly unproven 1

• EEG monitoring during spinal surgery is considered unproven according to evidence-based guidelines 1, 4
• The Aetna policy states EEG is only medically necessary "during carotid endarterectomy" or "intracranial vascular surgery"—not cervical spine procedures 1

G0453 (Continuous IONM): Not supported 1

• Without medical necessity for the underlying monitoring modalities, continuous monitoring cannot be justified 1
• The policy requires that monitoring be performed by specialty-trained personnel giving "undivided attention to a unique patient"—the chat transcript mentions "surgeon requests" but does not document contemporaneous interpretation 1

Policy-Specific Failures

The Aetna CPB 0697 criteria are not met:

• Documentation requirement: While the operative note mentions neuromonitoring remained stable, this does not establish medical necessity for ordering the monitoring in the first place 1
• Baseline testing issue: The policy states "baseline testing prior to intraoperative neuromonitoring requires contemporaneous interpretation prior to the surgical procedure"—the records show baseline data but do not clearly document this was obtained before intubation/positioning 1
• Specific exclusion applies: The policy explicitly lists this clinical scenario under "Insufficient Evidence or Unproven" 1

Common Pitfall: Confusing Routine Use with Medical Necessity

Many surgeons routinely order IONM for all cervical cases, but routine use does not establish medical necessity 5, 6:

• A 2023 review of 8,854 anterior cervical procedures found SSEP was used in 99.9% of cases, yet alerts occurred in only 2.7% 6
• The high utilization rate reflects practice patterns rather than evidence-based indications 6
• Recent 2025 data shows IONM may have prognostic value for long-term outcomes but does not demonstrate immediate protective benefit in preventing neurological injury during routine degenerative cases 7

When IONM Would Be Appropriate

IONM becomes medically necessary when high-risk features are present 1, 8:

• Severe cord compression with documented myelopathy: Requires intramedullary signal changes on MRI and clinical myelopathic findings (hyperreflexia, Hoffman's sign, clonus, gait disturbance) 1
• Ossification of posterior longitudinal ligament (OPLL): Demonstrated 84.2% sensitivity and 93.7% specificity for detecting complications 1
• Traumatic injury or significant deformity/instability: As defined in CPB 0743 1
• Tumor or intramedullary lesion: Where cord manipulation is anticipated 1

This patient has none of these high-risk features—the case represents routine multilevel ACDF for radiculopathy with moderate spondylosis.