Hypoglossal Nerve Schwannoma With Severe Brainstem Compression: Microsurgical Excision by Extreme Lateral Approach: 2-Dimensional Operative Video

Abstract

Abstract A 37-yr-old male presented with a history of left-sided tongue atrophy and fasciculations and weakness of upper limbs for 3 mo. Magnetic resonance imaging (MRI) revealed a large, partially cystic tumor with severe compression of the brainstem and spinal cord, with expansion and erosion of the hypoglossal canal. Computed tomography (CT) angiography showed the left vertebral artery to be anteriorly displaced by the tumor.  A retrosigmoid craniotomy and craniectomy were performed followed by mastoidectomy with unroofing the posterior aspect of the sigmoid sinus. The foramen magnum was completely unroofed. The hypoglossal canal was exposed with a diamond drill and an ultrasonic bone curette, and a tumor was seen within the expanded canal. C1 lamina was removed partially in the lateral aspect, and the occipital condyle was partially removed. After opening the dura mater, the tumor was found to be stretching the eleventh cranial nerve. The tumor was debulked, and dissected from the cranial nerve fibers. The vertebral artery, anterior spinal artery, and other branches displaced by the tumor were carefully preserved. The tumor was removed from the hypoglossal canal with a curette. The patient recovered well, with the resolution of his upper limb weakness. Patient modified Rankin Scale was 1 at 6-mo follow-up. The postoperative MRI showed a small remnant inside the hypoglossal canal, and it was treated by radiosurgery.  This 2-dimensional video demonstrates the technique of complete microsurgical removal of a complex tumor with preservation of cranial nerves and vertebral artery.  Informed consent was obtained from the patient prior to the surgery, which included videotaping of the procedure and its distribution for educational purposes. Also, all relevant patient identifiers have been removed from the video and accompanying radiology slides.