Neuromonitoring During PLIF Prevents Complications and Improves Surgical Success
February 27, 2025
Posterior Lumbar Interbody Fusion (PLIF) is a surgical procedure that addresses lumbar spine instability and degenerative issues through a less invasive spinal fusion. The process involves placing implants that help stabilize the spine while allowing the bones to fuse over time.
The focus of this case is the significant reduction of motor evoked potentials (MEPs) during the implant placement and the successful actions taken because of the real-time feedback provided by intraoperative neuromonitoring (IONM).
Patient Case Overview: Extensive Nerve Compression
A 60-year-old male presented with severe lower back pain radiating to the right hip and anterior thigh. He had a history of right L4/5 hemilaminectomy, medial facetectomy, and foraminotomy. Diagnosed with lumbar radiculopathy, the patient exhibited considerable muscle weakness in his right foot.
MRI results indicated a loss of disc height compressing nerves at L3-4, L4-5, and L5-S1. The patient also had grade 1 spondylolisthesis at L5-S1 and scoliosis at L4-5 and L3-4.
With scoliosis and radiculopathy exacerbating his pain levels, and conservative treatments failing to provide long-term relief, the surgeon elected to perform a PLIF at levels L3-S1 to alleviate the nerve compression, address the spinal instability, and improve the patient’s quality of life.
Neuromonitoring Intervention During PLIF Surgery
To mitigate the risk of nerve damage during surgery, a combination of monitoring modalities was used to track the patient's nerve and muscle function. The surgeon opted for a combination that included:
- Electromyography (EMG)
- Somatosensory evoked potentials (SSEPs)
- Transcranial electric motor evoked potentials (TCeMEPs)
- Electroencephalography (EEG)
During the placement of the left L5-S1 implant, the neurophysiologist observed a significant reduction in MEPs from the left medial gastrocnemius (MG) muscle. This drop in MEPs indicated a potential compromise to the patient’s nerve function.
In response, the surgeon paused the procedure to assess the situation. After a short period of observation, the MEPs from the left MG muscle returned to baseline levels, signaling the recovery of nerve function. The surgeon proceeded cautiously, ensuring stable neurophysiological responses were maintained throughout the rest of the procedure.
Free-running EMG was also used during the surgery, which captured intermittent spikes in activity in the bilateral tibialis anterior muscle (TA) during decompression. These spikes indicated mechanical irritation of the nerve roots. The surgeon was alerted to the spikes, carefully managed them, and avoided permanent damage.
Outcome of the Procedure
By the end of the surgery, all neurophysiological parameters returned to baseline or were within acceptable limits. SSEPs and MEPs were stable, indicating that the nerve function had been preserved, there was no significant abnormal EMG activity, and the train-of-four (TOF) assessment confirmed that neuromuscular blockade was reversed.
The surgeon was informed that all monitoring data were within acceptable limits at closure, and the patient was stable.
Potential Consequences Without Neurophysiological Monitoring
Without intraoperative neurophysiological monitoring, the significant drop in MEPs during implant placement at L5-S1 could have gone unnoticed. The failure to detect this reduction in real-time could have resulted in permanent nerve damage.
Nerve injuries during spinal surgeries can lead to severe postoperative complications such as muscle weakness, sensory loss, or even paralysis. In this case, the patient could have suffered from chronic pain and impaired mobility due to undiagnosed nerve compromise. Long-term complications such as reliance on assistive devices or further surgeries may have further impacted the patient’s quality of life.
Intraoperative monitoring allowed the surgical team to adjust their approach in real time. The patient’s nerve function and potential for an optimal recovery were preserved.
Real-Time Feedback Improves Procedure Success Rates
This case study highlights the importance of neurophysiological monitoring during complex spinal surgeries such as PLIF. The real-time feedback provided by monitoring modalities like SSEPs, MEPs, and EMG played a crucial role in preventing nerve damage and ensuring the overall success of the procedure. Through careful intraoperative management, the surgical team was able to address the patient's lumbar radiculopathy and spinal instability while preserving neurological function, ultimately improving the patient's quality of life.
For more information on the benefits of neuromonitoring and its role in enhancing patient care, please contact us or sign up for our newsletter.
