Unilateral isolated hypoglossal nerve palsy due to pathologically adherent PICA fusiform aneurysm – A case report
- Department of Neurosurgery, Shinshu University School of Medicine, Matsumoto, Japan
- Memfys Hospital for Neurosurgery, Enugu, Nigeria
Memfys Hospital for Neurosurgery, Enugu, Nigeria
DOI:10.4103/sni.sni_279_16Copyright: © 2017 Surgical Neurology International This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as the author is credited and the new creations are licensed under the identical terms.
How to cite this article: Mike E. Ekuma, Tetsuya Goto, Yoshiki Hanaoka, Kohei Kanaya, Tetsuyoshi Horiuchi, Kazuhiro Hongo, Samuel C. Ohaegbulam. Unilateral isolated hypoglossal nerve palsy due to pathologically adherent PICA fusiform aneurysm – A case report. 13-Jun-2017;8:114
How to cite this URL: Mike E. Ekuma, Tetsuya Goto, Yoshiki Hanaoka, Kohei Kanaya, Tetsuyoshi Horiuchi, Kazuhiro Hongo, Samuel C. Ohaegbulam. Unilateral isolated hypoglossal nerve palsy due to pathologically adherent PICA fusiform aneurysm – A case report. 13-Jun-2017;8:114. Available from: http://surgicalneurologyint.com/surgicalint-articles/unilateral-isolated-hypoglossal-nerve-palsy-due-to-pathologically-adherent-pica-fusiform-aneurysm-a-case-report/
Background:Isolated hypoglossal nerve palsy due to mechanical compression by a vascular lesion is rare.
Case Description:We report the case of a 72-year-old man who presented with a 4-year history of swallowing disturbance and subsequently progressively worsening left-sided tongue atrophy. He was referred to our department by a neurologist due a magnetic resonance imaging detected left vertebral artery compression of the medulla. Neurological examination was unremarkable except for left hypoglossal nerve dysfunction, which presented as left-sided atrophy and impaired movement of the tongue. Three-dimensional computed tomography angiography showed proximal left posterior inferior cerebellar artery (PICA) origin fusiform aneurysm. Microvascular decompression was done through a left transcondylar fossa approach. Intraoperative findings were thickened arachnoid around the lower cranial nerves, fusiform aneurysm of the left PICA at its origin from the left vertebral artery which was severely adherent to and compressing the left hypoglossal nerve rootlets.
Conclusion:The PICA has a very close relationship to the hypoglossal nerve, and its fusiform dilatation could cause isolated hypoglossal nerve dysfunction. Pathological adhesions between hypoglossal rootlets and the PICA aneurysm wall could be a possible contributor in the development and progression of hypoglossal nerve palsy.
Keywords: Adhesion, chronic arachnoiditis, fusiform aneurysm, hypoglossal nerve palsy, vascular compression
Hypoglossal nerve (HN) palsy is not an uncommon neurological disease. It has varied etiologies and is usually associated with dysfunctionality of other lower cranial nerves.[
A 72-year-old man was referred from a local hospital with a 4-year history of swallowing difficulty which progressively worsened over time. He also had occasional episodes of aspiration. There was no history of neck trauma, headache, dysarthria, or gait problems. He was a known hypertensive but not a diabetic. He had a positive history of subarachnoid hemorrhage (SAH) from a ruptured middle cerebral artery aneurysm, which was managed surgically (not clipped) at a local hospital 35 years before the present illness. Laryngeal endoscopy showed no obstructive lesion, however, videoendoscopy and videofluoroscopy revealed delayed swallowing reflex and occasional aspiration.
In our hospital, he was initially managed by the otorhinolaryngologists (ORL) as an outpatient. He developed left-sided tongue atrophy [
Preoperative images: plain CT (a) showing PICA aneurysm wall calcification (arrow); axial T2-WI (b and c) showing the left VA and PICA (arrow) running very close to the left HN rootlets (arrow); CTA (d) showing left PICA origin fusiform aneurysm (arrow); MRA showing the PICA (arrow) before (e) and after (f) transposition (arrow)
General physical examination was unremarkable. Neurological examination showed an alert elderly man with intact higher cerebral function. He had left tongue atrophy and impaired movement of the tongue. Other cranial nerves were intact. Sensorimotor system examination was normal and coordination was good. He was worked up for MVD after an informed consent was obtained.
Operation and postoperative course
The MVD was done through a left transcondylar fossa approach. Intraoperative findings were thickened arachnoid around the lower cranial nerves and fusiform aneurysm of the left PICA at its origin from the left VA which was severely adherent to and compressing the left HN rootlets [
Postoperatively, the patient's preoperative neurological status was preserved. MR Angiogoraphy showed anterior medullary segment of PICA was successfully transpositioned without stenosis [Figure
The HN is a pure motor nerve that innervates all intrinsic and extrinsic muscles of the tongue except the palatoglossus muscle.[
The hypoglossal rootlets are closely related to both the VA and PICA. The relationship of the HN rootlets to PICA varies significantly. The PICA can arise below, above, or at the level of the rootlets. Those that arise below or above the rootlets usually course superior or inferior to the rootlets rather than through them. Those that arise at the level of the rootlets usually course in between and frequently stretch the hypoglossal rootlets.[
There have been a few reports in literature of isolated HN palsy caused by mechanical compression by normal or abnormal intracranial vessels.[
Fusiform PICA aneurysms are difficult to treat and direct clipping is usually not possible due to circumferential dilatation of the vessel. Surgical approaches previously described include clip/wrapping, segmental sacrifice, flow reversal with proximal occlusion, distal occlusion, and bypass with trapping.[
The PICA has a very close relationship to the HN and its fusiform dilatation could cause isolated HN dysfunction. Pathological adhesions between the HN rootlets and the aneurysm wall could be a contributor in the progression of nerve dysfunction.
The authors have no financial, personal, or professional interest that could influence this work. An informed consent obtained from the patient before submission of this manuscript.
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Conflicts of interest
There are no conflicts of interest.
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