Cervical Surgical Procedures

1. While brachial plexus injury due to traction or over tightening of the shoulders during cervical  procedures isn't common it is important to guard against this possibility. Utilizing SomatoSensensory  Evoked Potentials (SSEPs) with stimulating electrodes place either at the ulnar or median nerve we can  help prevent neurological damage to the plexus. TransCranial Motor Evoked Potentials (TcMEP) can  similarly detect any possible injury and are can be utilized as a secondary means of corroboration. 

2. During exposure special care should be taken while entering the pretracheal fascia to avoid recurrent  laryngeal nerve (RLN) palsy. Injuries can be prevented, via ElectroMyographical (EMG) monitoring of  the bilateral RLNs. Utilizing a 4 channel recording electrode on the endotracheal tube, that is  strategically placed by the anesthesia team. These electrodes can detect possible injury due to traction. 

3. Once exposure is complete and decompression begins, attention is shifted, to prevention of nerve  root and spinal cord injury. EMG monitoring is utilized, to guard against nerve root damage.  Subdermal recording electrodes are placed in the specific dermatonal zones which correlate to the  spinal levels being operated on.The spinal cord is monitored via SSEP and TcMEP monitoring. This is  most important during interbody (graft) placement and subdural tumor resection, but it is imperative to  establish a preincision baseline as well as to utilize a continuous monitoring approach during the  entirety of the case to establish a real time assessment of the integrity of the cord. It is important to note  that monitoring the ascending (sensory) and descending (motor) tracts of the spinal cord is essential.  This ensures the integrity of both the dorsal and ventral side of the cord. The motor tract is monitored  by stimulation of the primary motor cortex with subdemal needle electrodes and recording at upper  limb and lower limb bilateral muscle groups. Typically we record at level specific muscles and add the  abductor pullucis brevis and the abductor hallucis to ensure complete coverage. Monitoring the sensory  tract employs stimulation at the ulnar/median nerves for upper limb and at the tibial nerve for lower  limb. 

4. Direct nerve stimulation utilizing a monopolar hand held probe can be utilized to verify nerve root  integrity at any point during the procedure.

Applies to all Cervical Procedures, including ACDFs, PCDFs, and Thyroidectomies 

Cervical procedures present a layered set of neurological risks that evolve as surgery progresses through positioning, exposure, decompression, and instrumentation. A well-designed monitoring approach addresses each phase sequentially, with modalities selected based on the specific structures at risk.

• During decompression, it is crucial to monitor against any nerve root damage. The  utilization of electromyography (EMG) helps us detect any irritation caused by retractor,  forceps or any other surgical tool. Special attention is placed on emg monitoring during  these crucial periods and irritation is easily and quickly detected.



• Another use for emg is nerve isolation. Utilizing a flush tipped stimulation probe with a  stim value of 0.3 to 3 mA we can aid the surgeon in identifying nerve roots. This is  especially useful for discectomies. 
  

• During anterior cervical exposure, the recurrent laryngeal nerve (RLN) is at risk from retraction within the pretracheal fascia. Continuous EMG monitoring of the bilateral RLNs is performed using a four-channel recording electrode system mounted on the endotracheal tube, strategically positioned by the anesthesia team. This setup provides real-time detection of traction-related RLN irritation, enabling the surgeon to adjust retractor tension before injury occurs.
  

• Once decompression begins, monitoring attention shifts to the spinal cord and segmental nerve roots. Subdermal EMG recording electrodes are placed in dermatomal distributions corresponding to the operative levels to detect nerve root irritation from instrumentation, retraction, or decompressive maneuvers.

• Spinal cord integrity is maintained through continuous SSEP and tcMEP monitoring, which assess the sensory (dorsal) and motor (ventral) tracts independently. This dual-pathway approach is essential — changes isolated to one modality can indicate focal injury to a single tract that would be missed if only one modality were used. Upper limb SSEPs are derived from ulnar and/or median nerve stimulation; lower limb SSEPs from posterior tibial nerve stimulation. tcMEP recordings target level-specific upper and lower limb muscle groups, with standard inclusion of the abductor pollicis brevis and abductor hallucis to ensure comprehensive coverage. Monitoring is established from pre-incision baseline and maintained continuously through case completion — particularly during interbody graft placement and any tumor resection.
  

Applies to all Cervical Procedures, including ACDFs, PCDFs, and Thyroidectomies 

Introductory Overview

Decompressing

Exposure and Recurrent Laryngeal Nerve Monitoring

Decompression: Spinal Cord and Nerve Root Surveillance

Direct Nerve Stimulation

• A monopolar handheld stimulation probe is available throughout the procedure for direct verification of nerve root identity and integrity. This is particularly useful during decompression and instrumentation when anatomical landmarks may be obscured.
  

Direct Nerve Stimulation

• Recurrent laryngeal nerve (RLN) injury — whether transient or permanent — is among the most consequential complications of thyroid surgery. Continuous EMG monitoring of the bilateral RLNs is performed using a four-channel recording electrode system on the endotracheal tube, providing real-time detection of retraction-related nerve irritation throughout exposure and dissection.

• A 90mm flush-tipped direct nerve stimulation probe is also provided for intraoperative nerve identification and pre/post-resection signal acquisition. Confirmed nerve response prior to resection and preserved signal integrity following mass excision provide objective documentation of RLN functional status — critical both for patient safety and for medicolegal purposes.