This patient was a 67-year-old male who presented with a recent fall four days prior to surgery that resulted in severe spondylotic changes with cord compression at C3-7. Patient was experiencing numbness and weakness in bilateral legs and feet and was unable to walk since the fall.
Relevant health history factors were: stroke 1 year prior, type 2 diabetes, hypertension, and a cardiac stent. Pre- and post-position SSEPs and MEPs were obtained and deemed reliable prior to incision by interpreting physician.
Decompression began approximately 40 minutes after incision was made. 10 minutes after decompression began, left ulnar nerve SSEP and bilateral posterior tibial nerve SSEPs attenuated.
Surgeon informed technologist that she was decompressing at C5-6 level at the time of attenuation. She also noted that there was a small dura tear that occurred while she was decompressing at that level, which corresponded with when we initially saw the drop in SSEPs. Surgeon irrigated the injured area.
The surgeon moved on to decompress the next level. 20 minutes after she began decompressing the next level, SSEPs returned to within baseline limits.
TcMEPs remained stable during the SSEP attenuation and their return to baseline. However, 10 minutes after SSEPs returned to baseline, right AH TcMEPs attenuated and left sided TcMEPs were lost completely. To4 was 4/4 as patient had been fully reversed. Surgeon attempted to clean the surgical area with irrigation.
Closing began 40 minutes after the initial attenuation in MEPs. Very small responses in left side MEPs returned while right TA-MG and AH MEP responses were lost completely at close.
SSEPs remained stable for the remainder of the case and at closing.
In a post-op evaluation of the patient, patient could move all four extremities on command.
However, the left side extremities were much weaker than the right-side extremities, which is consistent with the loss of SSEPs and TcMEPs even though signals returned at close.
It is reasonable to think that without neuromonitoring, the surgeon would have continued decompression to the point of complete loss of SSEPs and TcMEPs.
Haley McCarver, CNIM