dysmorphism (tethered cord), split cord malformation. (Diastematomyelia) and scoliosis. ENEFIT F NTRAOPERATIVE EUROPHYSIOLOGICAL ONITORING (. ) N.
BENEFIT OF INTRAOPERATIVE NEUROPHYSIOLOGICAL MONITORING (IONM) IN A PEDIATRIC PATIENT WITH SPINAL DYSMORPHYSIM, SPLIT CORD AND SCOLIOSIS. Faisal R. Jahangiri, MD, CNIM, D.ABNM, FASNM1,2; Samir Al Sayegh, MD3; Moutasem Azzubi, MD4; Abdulrahman M. Alrajhi5; Monerah M. Annaim6; Shmoukh A. M. Al-Sharif6; Tanweer Aziz, MD7; Sami Al Eissa, MD3 1 Division
of Neurology, Department of Medicine, 3Division of Orthopedics, Department of Surgery, 6College of Medicine-Female, KSAU-HS; 7Department of Anesthesiology; King Abdulaziz Medical City, Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia. 5College of Medicine – King Saud University, Riyadh, Saudi Arabia; 2Jahangiri Consulting LLC, Charlottesville, Virginia, USA.
IONM DATA
BACKGROUND Spinal Cord Malformation (SCM) is a rare, uncommon congenital anomaly, where a segment of the spinal cord is subdivided longitudinally into two hemicords. These the two segments unite again below the split. It has been described as milder and most common form of spinal dysraphism, with a reported incidence rate of 3.8-5% of all spinal cord anomalies. It’s mainly a condition of children, as it has been well documented, symptoms and accompanied neurological deficits related to congenital anomalies may not appear at birth, but they start to appear with child’s growth as a result of spinal cord continuous tethering with the growth. These symptoms can be categorized into three main categories: neurological, cutaneous and orthopedic manifestations.
A retrospective analysis was performed on one pediatric patient who underwent twelve operations for the correction of scoliosis, split cord and untethering of the spinal cord. A multimodality IONM protocol including Somatosensory Evoked Potentials (SSEP), Transcranial electrical Motor Evoked Potentials (TCeMEP) and Electromyography (EMG) was utilized during the last six procedures.
RESULTS
OBJECTIVE To demonstrate the role of multimodality Intraoperative Neurophysiological Monitoring (IONM) in preventing intraoperative neurologic insult and minimizing any postoperative neurological deficits in a patient with spinal dysmorphism (tethered cord), split cord malformation (Diastematomyelia) and scoliosis.
Data 1. Baseline left & Right TCeMEP
Data 3. Closing Left TCeMEP
Pre-operative lateral & PA x-rays of the patient showing significant scoliosis.
Post-operative image showing Magec growing rod.
METHODS
Data 5: Left Ulnar & Tibial SSEP
Data 2. Loss of Lower TCeMEP
Data 4: Closing Right TCeMEP
Data 6: Right Ulnar & Tibial SSEP
The patient underwent six neurosurgical and orthopedic procedures from age 3 to 6 years. This included release of tethered cord, resection of filum terminale, removal of bony spur at T11-T12 level and release of adhesions at L3 level. This was followed repair of subcutaneous meningocele, correction of scoliosis with VEPTR (Vertical Expandable Prosthetic Titanium Rod) technique, and expansion of VEPTR every six months. All these procedures were done without Intraoperative Neurophysiological Monitoring (IONM) and without any post-operative neurological deficits. At age six (procedure #7) a VEPTR expansion with multimodality IONM was performed. During VEPTR release, first left lower and later right lower MEPs were lost. Surgeon slightly expanded VEPTR and cancelled spinal correction resulting in reappearance of TCeMEP responses before closing. Patient moved all extremities post-operatively. The post-operative MRI showed partial split cord malformation with re-tethering of spinal cord. The patient underwent surgery for the repair of split cord malformation and release of tethered spinal cord with IONM. After laminectomy an intracanal bone spur was found. The dura was exposed, a cartilage like band attached to the cord was identified extending from the dura to the dorsal surface of the cord. Careful dissection with microsurgical technique was made. The cartilage band was completely removed. The cord was spitted. All arachnoid and adhesions in between the cord and the dura were removed. Then filum terminale was isolated utilizing 1.0-2.0 mA triggered EMG (t-EMG). The last five (5) procedures done with IONM were without any intraoperative changes.
CONCLUSIONS This patient was operated for the correction of scoliosis, split cord and tethered cord. Utilization of IONM for this patient was extremely helpful. Sudden loss of lower TCeMEP resulted in cancellation of the procedure and MRI showed a thick remnant attached to the spinal cord. If the procedure was done without IONM the underlying pathology could have been missed resulting in paraplegia. A multimodality IONM can be confidently used to identify any underlying neurophysiological changes during complex surgical procedures. This reduces the risks of post-operative neurological deficits due to surgical damage and incomplete untethering of the spinal cord. We strongly recommend to utilize IONM during high risk surgical procedures to avoid any post-operative neurological deficits.
