TITLE:
Evolution and Role of Intraoperative Neurophysiological Monitoring in Intramedullary Spinal Cord Surgery: A 2-Year Series from Saudi Arabia
AUTHORS:
Saleh Baeesa, Emmanuel Labram, Mohammed Bin Mahfoodh, Mohammed Khalid, Youssef Al-Said
KEYWORDS:
Neurophysiological Monitoring, Intramedullary Spinal Cord Surgery
JOURNAL NAME:
World Journal of Neuroscience,
Vol.4 No.4,
July
23,
2014
ABSTRACT: Introduction: Despite recent advances in neuroimaging and microsurgical
techniques, surgical resection of spinal cord tumours remains a challenge.
However, the evolution with advances and refinement of neurophysiological
equipment and methodologies, intra-operative neurophysiolo- gical monitoring
(IONM) is now regarded as an essential adjunct to the surgical management of
intramedullary spinal cord tumours. This study aims to report our preliminary
experience with IONM and emphasise its effective role of achieving maximum tumour
resection and minimising neurological injury. Methods: This is a retrospective
study performed at our institution between July
2012 and August 2013. It included a cohort of 6 consecutive patients presented
with intramedullary spinal cord tumours. Their mean age was 26 years
(range, 4 months - 37 years), all were males, and the mean follow up was 11.6
months. Results: We combined the use of somatosensory evoked potentials (SSEPs)
and motor evoked potentials (MEPs) in spinal cord surgery. SSEPs are monitored during
the incision of the dorsal midline of the spinal cord and this was used in two
of our patients and MEPs were used as an essential monitoring during the tumour
resection. In addition, we used free-running electromyography (EMG) and muscle
MEPs (mMEPs) during tumour resection. Four of our patients (two with
ependymoma, one with ganglioglioma, and one with pilocytic astrocytoma) had
complete tumour resection and two patients (pilocytic and diffuse astrocytoma) had
IONM changes during surgery and had partial tumour resection. At 6-month follow
up all our patients had made a good recovery with no new neurological sequelae.
Conclusion: This small series and literature review is presented to add and
improve the understanding of IONM in intramedullary spinal cord procedures and
to reinforce the importance of IONM in optimising tumour resection and
neurological outcome. Our series confirm that without D-wave monitoring,
free-running EMG and MEP monitoring during tumour resection remain an important
adjunct. We also draw attention to the fact that changes in the free-running
EMG occur before any changes in the MEPs are noted.