Enhancing Patient Safety in an ACDF Surgery with Intraoperative Neuromonitoring
February 27, 2025
Anterior cervical discectomy and fusion (ACDF) is a widely performed surgical procedure for treating nerve root or spinal cord compression in the neck. For patients experiencing symptoms like chronic neck and back pain, weakness, numbness, or tingling in the arms and neck, an ACDF surgery can help them find relief and regain quality of life.
While ACDF surgery typically lasts 1-2 hours and has high success rates, it is not without risks. Potential complications include neurological injury, infection, hardware failure, and vascular injury, among others. One important safeguard against these risks is the use of intraoperative neurophysiological monitoring (IONM), which helps surgeons detect and address neural changes in real time, minimizing the chances of postoperative deficits. This case study highlights the importance of IONM during a C6-C7 ACDF procedure.
Patient Case Overview: Chronic Pain and Worsening Condition
The patient was a 58-year-old male with a history of chronic neck and back pain. Over time, his condition worsened, and he began experiencing more severe symptoms, including pain radiating into his arms, difficulty maintaining balance, and frequent episodes of dropping things. He also reported significant discomfort when turning his head, particularly while driving.
The patient’s medical history included hypertension and diabetes, both of which were well-controlled with medication. He had also undergone multiple prior surgeries, including bilateral knee replacements and a right ankle and foot fusion. After reviewing radiological imaging, signs of cervical myelopathy, spondylosis, and spondylolisthesis were evident, specifically at the C6-C7 level. This was accompanied by spinal cord compression, which explained the patient’s worsening neurological symptoms.
Decompressing and Stabilizing the Spinal Cord
The surgeon determined that performing a C6-C7 ACDF was the best option to decompress the spinal cord and nerve roots, providing the patient with the greatest opportunity for neurological recovery and preventing further decline.
The procedure involves accessing the cervical spine through an anterior approach and removing the damaged or herniated disc, followed by a fusion of the affected vertebrae using bone grafts or implants. The key here is that ACDF surgery alleviates pressure on the spinal cord and nerve roots while also stabilizing the cervical spine, reducing the risk of further deterioration.
Intraoperative Neuromonitoring for an ACDF Procedure
Throughout the procedure, the patient was positioned supine. As part of the standard protocol, intraoperative neurophysiological monitoring was employed to track neural function in real time. Specifically, somatosensory evoked potentials (SSEPs) and motor evoked potentials (MEPs) were used to monitor nerve integrity and detect changes in nerve signaling.
At one point during the surgery, changes to these modalities indicated potential nerve compression or damage:
- The right ulnar nerve’s SSEP showed a significant increase in latency of approximately 10%, along with a marked decrease in amplitude.
- MEPs recorded from the right flexor carpi radialis (FCR) and flexor carpi ulnaris (FCU) muscles showed a dramatic decrease in signals—between 70% and 80% of their baseline values
Intervention and Outcome
Upon observing these changes, the neurophysiologist immediately alerted the surgical team who took immediate corrective action. The technologist overseeing the monitoring responded by adjusting the surgical tape around the patient’s right arm and the patient’s overall positioning. Following the adjustments, the neurophysiological data quickly improved. The right ulnar nerve SSEP returned to normal limits, and the MEP signals for the FCR and FCU muscles improved to a 50% reduction from baseline, a significant improvement from the earlier 70-80% decrease.
Thanks to the quick intervention, the patient woke up after the operation without any new neurological deficits. His recovery was closely monitored, and there were no signs of lasting damage to the nerves or muscles.
Potential Consequences Without Neurophysiology Monitoring
This case underscores the vital role of neurophysiological monitoring in complex spinal surgeries like ACDF. Had the monitoring not been in place, the changes in the patient’s SSEPs and MEPs may have gone unnoticed, potentially leading to long-term neurological deficits.
For example, the loss of signals from the ulnar nerve and the FCR/FCU muscles could have resulted in weakness, numbness, or paresthesia in the patient’s ring and little fingers, or pain in the forearm or inner elbow. Without the immediate action taken during surgery, these issues could have been permanent, severely impacting the patient’s quality of life post-surgery.
Improving Patient Outcomes
Anterior cervical discectomy and fusion surgery is an effective treatment for patients with cervical spine compression, but like any surgery, it carries inherent risks. The use of intraoperative neurophysiological monitoring significantly reduces these risks by providing real-time feedback on nerve function, allowing for immediate corrective action. In this case, the timely detection and intervention prevented potential long-term neurological deficits, ensuring the patient’s best chance for a full recovery. Neurophysiological monitoring is not just a tool—it’s an essential component of successful ACDF procedures.
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