Ulnar Nerve Positional Change for Posterior Lumbar Case
August 07, 2024
For many suffering from degenerative disc disease, waking up every day with debilitating back pain that radiates through their hips is the norm. Degenerative disc disease is characterized by the shrinking and wearing down of vertebrae. This degeneration can result in disc herniation and narrowing of the spinal canal. Common symptoms from these conditions include things like neck and back pain, numbness, and weakness in the extremities.
That’s the baseline for our 31-year-old male patient. Diagnosed with degenerative disc disease, posterior disc herniation, and severe spinal canal stenosis of the lumbar spine, the patient presented with mid and lower back pain radiating to the hips. Despite using prescription medications like Medrol and Flexeril, he experienced minimal relief.
Surgical treatments for degenerative disc disease include laminectomy, posterior lumbar fusion, and microdiscectomy.
Neurophysiological Monitoring During Surgery
In preparation for the surgery, the surgical team employed several neurophysiological monitoring modalities: somatosensory evoked potentials (SSEPs) from the ulnar and tibial nerves, transcranial electric motor evoked potentials (TCeMEPs), electromyography (EMG), train of four (TOF) monitoring, and electroencephalography (EEG) for depth of anesthesia.
During the microdiscectomy procedure, there was a significant reduction of more than 50% in the left ulnar nerve signal. This attenuation raised concerns about potential nerve damage due to compromised blood flow, likely resulting from the patient's arm positioning.
To address the attenuation, the surgical team adjusted the positioning of both arms. After the adjustment, the SSEPs returned to baseline levels and remained stable throughout the procedure. At the time of closing, SSEP and MEP readings were within normal limits compared to the baseline. Additionally, there was no abnormal activity in the EMG readings, and the TOF showed a 4/4 count, indicating adequate neuromuscular blockade recovery.
Possible Consequences Without Neurophysiology
Had the surgical team not employed SSEPs, they might not have detected that the arm positioning was compromising the ulnar nerve. Failure to readjust the arms could have led to potential sensory and motor deficits post-operatively as a result of inadequate blood flow. Intraoperative neuromonitoring plays a critical role in preventing nerve damage during spine surgeries. It introduces more insight and data into the operating room for better and faster decision-making.
By utilizing modalities such as SSEPs, TCeMEPs, EMG, TOF, and EEG, this operation’s surgeons were able to better detect and mitigate potential nerve injuries in real time. The successful outcome of this posterior lumbar case demonstrates how proactive monitoring and timely intervention can preserve neurological function and enhance patient recovery.
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