232
Surg Neurol 1992 ;38 :232-5
Repositioning of the Tortuous Vertebrobasilar Artery for Trigeminal Neuralgia: A Technical Note Akira Ogawa, M .D., Michiyasu Suzuki, M .D., Reizo Shirane, M.D., and Takashi Yoshimoto, M .D . Division of Neurosurgery, Institute of Brain Diseases, Tohoku University School of Medicine, Sendai, Japan Ogawa A, Suzuki M, Shirane R, Yoshimoto T . Repositioning of the tortuous vertebrobasilar artery for trigeminal neuralgia : a technical note . Surg. Neurol. 1992 ;38 :232-5 . A patient with trigeminal neuralgia caused by a tortuous vertebrobasilar artery is reported . To obtain safe and certain neurovascular decompression of the trigeminal nerve, the tortuous vertebrobasilar artery was repositioned by pulling it toward the dura mater of the clivus using a synthetic vascular slip . The authors describe the technique of repositioning of the tortuous vertebrobasilar artery and its usefulness. KEY WORDS : Hemtfactal spasm ; Neurovascular compression ; Tic convulsi£; Trigeminal neuralgia ; Vertebrobasilar artery
Microvascular decompression, in which a prosthesis is inserted between a vessel and a nerve, is the method of treatment most often chosen for trigeminal neuralgia or hemifacial spasm [12,13] . It has long been known, however, that symptoms may be due not only to neurovascular compression by small intracranial arteries or veins, such as the superior cerebellar artery, the anterior inferior cerebellar artery, or the posterior inferior cerebellar artery, but also to direct compression by a tortuous or elastic vertebrobasilar artery [5] . This kind of disorder is not considered to be rare ; however, operative results are not favorable [1,2,3,7-10,14,15,17-24] . Since the tortuous vertebrobasilar artery is firm and not readily movable, it is not easily decompressed by the insertion of a prosthesis between the artery and the nerve . Although various surgical techniques have been used in such cases, there have been no reports of attempts to relieve the neurovascular compression by means of repositioning the tortuous vertebrobasilar artery itself . We have obtained favorable results using such a technique . The vertebrobasilar artery is repositioned by wrapping it in a
Address reprint requests to: Akira Ogawa, M .D ., Division of Neurosurgery, Institute of Brain Diseases, Tohoku University School of Medicine, 1-1, Sciryo-machi, Aoba-ku, Sendai 980, Japan . Received November 11, 1991 ; accepted February 14, 1992 .
L' 1992 by
Elsevier
Science Publishing Co., Inc .
synthetic slip and pulling it toward the dura mater of the clivus . We describe this technique and our results in this technical note .
Case Report The patient was a 56-year-old man complaining of trigeminal neuralgia of 3 years' duration . Onset was characterized by intermittent pain of the left cheek and twitching of the left orbital region . About I week after onset, neuralgia extended to the entire left side of the face. The twitching of the left orbital region subsided in about 3 months, but he began to experience transient episodes of tinnitus at about that time . A trigger zone for the trigeminal neuralgia was present in the region of the left mouth, and it gradually worsened . About 6 months before hospitalization, he started receiving carbamazepine, but there was no improvement in his symptoms . The pain increased, and it became too painful to wash his face . Other than mild hypertension without treatment, there was nothing notable in his past or family history . No notable neurological findings were obtained at the time of admission . Cerebral angiography disclosed elongation and dilation of the vertebrobasilar artery, tortuousity, and rostral and lateral displacement (Figure LA) . In TI-weighted magnetic resonance imaging (MRI) scans, the course of the vertebrobasilar artery indicated angiographically was depicted as a flow void, and the trigeminal nerve was compressed and displaced rostrally by the basilar artery (Figures 2 and 3A) .
Surgery
A left suboccipital craniotomy was used . To obtain a wide operative field around the vertebrobasilar artery, a craniotomy was performed rostrally to the angle of the transverse sigmoid sinus and caudally to the foramen magnum . The vertebral artery was found directly below the lower cranial nerves . There was no notable arteriosclerosis . The facial and acoustic nerves were compressed and displaced laterally by the vertebral artery . 0090-3019/92/S5A0
Repositioning of Tortuous VBA
Surg Neurol 1992 ;38 :232-5
2 33
Figure 1. Preoperative and postoperatire angiograms ; anterioposterior projection . (A) Preoperative angtogram showing displacement of the tortuous and elongated vertebrobasilar artery (arrowhead) rostrally and laterally . (B) Postoperative angiogram showing repositioning of the tortuous vertebrobasilar artery (arrowheadl caudally and medially . Thedistance between the basilar artery and superior cerebellar artery had widened.
The trigeminal nerve was strongly compressed rostrally by the basilar artery and had become thin . It was determined that using the usual means for inserting a prosthesis between the vessel and the nerve would further aggravate the compression of the trigeminal nerve . Therefore, a synthetic vascular graft (Gore Texu vascular graft) was made into a 6-mm-wide slip and wound around the distal part of the vertebral artery between the acoustic nerve and the glossopharyngeal nerve . This slip was sutured
with 8-0 nylon thread and attached to the vertebral artery . Then, the slip was immobilized on the vertebral artery, and the dura mater of the clivus in the midline portion was sutured using 6-0 nylon thread . The vertebrobasilar artery was pulled in a caudal midline direction, thus relieving the trigeminal, facial, and acoustic nerves from compression by the vertebrobasilar artery (Figure 4) .
Postoperative Course
Figure 2 . Preoperative MR] scan ; 7 I-weighted coronal image (TR 500 net. TE 20 ms) .
Postoperatively, the trigeminal neuralgia was abolished completely without any neurological symptoms . In postoperative angiograms, the rostral and lateral tortuousity of the vertebrobasilar artery was found to have decreased (Figure 2B) . MRI then showed a gap between the trigeminal nerve and flow void of the basilar artery . The displacement of the trigeminal nerve had decreased, and it ran in a straighter course (Figure 3B) . Eighteen months postoperatively, the patient showed no recurrence of any of his symptoms .
Discussion Recently, microvascular decompression has generally been performed for the treatment of trigeminal neuralgia . The vessel responsible for the neurovascular compression is most commonly the superior cerebellar artery, but can also be the anterior inferior cerebellar artery or the intratentorial veins [12] . With such small intracranial arteries or veins, it is normally an easy matter
234
Surg Neurol 1992 ;38: 2 32-5
Ogawa et al
3 . Enhanced Ti-weighted coronal image in the area indicated by Figure 2. (A) Preoperative image depicting the basilar artery as a/low void (arrow displaced rose rally and laterally . The trigeminal nerve (asterisk) is compressed and displaced rostrally by the basilar artery . (B) Postoperative image showing a gap between the trigeminal nerve (asterisk) and the flow enid of the basilar artery (arrmv . The displacement of the trigeminal nerve has decreased, and its course is straighter. Figure
4 . lntraoperative drawing from the left cerebellopontine angle. The synthetic clip immobilized on the vertebral artery was pulled by 6-0 nylon thread toward the dura mater of the clirus . The elongated and tortuous vertebrobasilar artery was moved in a caudal and medial direction, which relieved the trigeminal, facial . and acoustic nerves from compression by the vertebrobasilar artery . A . trigeminal nerve : B, acoustic and facial nerve; arrow, 6-0 nylon thread; asterisk, synthetic clipcropped around and immobilized on the vertebral artery . Figure
000
1
to move the vessel after dissecting it from the surrounding arachnoid membrane. Therefore, alleviation of the compression of nerves by such vessels by placing a prosthesis between them is relatively easy . However, there are also patients with trigeminal neuralgia or facial spasm in whom the responsible vessel is a dilated and tortuous vertebrobasilar artery [1,2,3,7-10,14,15, 17-24). In addition, a number of authors have reported the presence of a tortuous and ectasic vertebrobasilar artery associated with both trigeminal neuralgia and facial spasm (tic convulsif) [2,4,7,8,10,17,19,20) . The present case had both trigeminal neuralgia and facial spasm transiently and is thought to have had a similar cause. For cases in which neurovascular compression is thought to be due to a tortuous and elongated vertebrobasilar artery, intracranial rhizotomy [2,7,8,10,18,23] and thermocoagulation [15,19) have primarily been used, since decompression is not easily performed . There have been some reports of favorable results when neurovascular decompression was accomplished with a prosthesis [17,20] . Satisfactory results have not often been achieved, however, with regard to recurrence and various degree of cranial nerve palsy [4,22] . Because the vertebrobasilar artery is a large artery and is not readily movable, it should be expected that placing a prosthesis between the artery and the nerve will only increase the compression . For this reason, satisfactory results have not been obtained . There have been no reports of attempts at repositioning the vertebrobasilar artery itself to relieve the neurovascular compression . As was clear in the present case, a tortuous vertebrobasilar artery can compress the trigeminal and facial nerves in a rostral and lateral direction, and it is necessary to move the vessel in a mediocaudal direction to obtain effective decompression of the nerves . To move the tortuous and elongated artery without kinking, we use a synthetic slip, winding it around and securing it to the vertebral artery . Then the encircled vertebral artery is pulled upon with nylon thread . In this manner, a tortuous vertebrobasilar artery can be repositioned without kinking, and decompression of the affected nerves can be achieved . The synthetic slip is wound around the distal part of the vertebral artery above the posterior inferior cerebellar artery . In this portion, perforating arteries directly branching from the vertebral artery are rare [6,11,16) . In addition, the perforating branches from the basilar artery to the brain stem can be expected to have been stretched by the displacement of the basilar artery in a rostrolateral direction . Therefore, it is considered unlikely that repositioning in a mediocaudal direction will have any effect on the perforating branches . In fact, comparison of the preoperative and postoperative angiograms and MRI in this
Repositioning
of Tortuous
VBA
Surg Neurol
235
1992 ;38 : 2 3 2 -5
case showed a repositioning
of
the vertebrobasilar ar-
tery . Clinically, there have been no symptoms emia
of the
of
isch-
brain stem, and the previous symptoms dis-
appeared immediately postoperatively .
As
indicated above, to obtain safe and certain neuro-
vascular decompression tery, it
is
of a
tortuous vertebrobasilar ar-
necessary to move the artery in a mediocaudal
direction . Here we have described a technique for the movement
of
an elongated and tortuous artery in the
desired direction without kinking, stenosis, or occlusion, and the favorable results achieved thereby .
resonance imaging of vertebrobasilar ectasia in tic convulsif . A case report. J Neurosurg 1991 ;74 :999-1003 . 11 . Hassler O. Arterial pattern of human brain stem . Normal appearance and deformation in expanding supratentorial conditions . Neurology 1967 ;17 :368-75 . 12 . Janetta PJ . Neurovascular compression in cranial nerve and systemic disease . Ann Surg 1980 ;192 :518-25 . 13 . Janetta PJ, Abbasy M, Maroon JC, Ramos FM, Albin MS. Etiology and definitive microsurgical treatment of hemifacial spasm . Operarive techniques and results in 47 patients . J Neurosurg 1977 ;47 :321-8 . 14 . Kerber CW, Margolis MT, Newton TH . Tortuous vertebrobasilar system : a cause of cranial nerve signs . Neuroradiology 1972 ;4^4-7 . 15 . Lye HL . Basilar artery ectasia : an unusual cause of trigeminal neuralgia. J Neurol Neurosurg Psychiatry 1986 ;49 :22-8 .
References I . Bingas B, Cotsou S . Cerebello-ponrine angle syndrome with uncommon etiology (a case report) . Neuroradiology 1972 ;3 :165-6 .
16. Marmood A, Dujovny M, Torche M, Dragovic L, Austrian JI . Microvascular anatomy of foramen caecum medullare oblongarae. J Neurosurg 1991 ;75 :299-304 .
2 . Campbell E, Keedy C . Hemifacial spasm: a note on the etiology in two cases . J Neurosurg 1947 ;4 :342-7 .
17 . Miyagi J, Hanabusa Y, Kuramoto S, Kubuyama M, Kajiwara K . Neurovascular decompression for trigeminal neuralgia associated with hemifacial spasm . Neurol Med Chic (Tokyo) 1986 ;26 :900-3 .
3 . Carella A, Caruso G, Lamberti P . Hemifacial spasm due to elongation of the distal segment of the vertebral artery . Report of two cases . Neuroradiology 1973 ;6 :233-6 .
18 . Nergoy DR, Dohn DF . Hemifacial spasm secondary to vascular compression of the facial nerve . Cleve Clin Q 1974 ;41 :205-14 .
4 . Cook BR, Janetta PJ . Tic convulsif : results in I I cases treated with microvascular decompression of the fifth and seventh cranial nerves . J Neurosurg 1984 ;61 :949-51 . 5 . Dandy WE . Concerning the cause of trigeminal neuralgia . Am J Surg 1934 ;24 :445-55 . 6 . Gabrielsen TO, Amundsen P. The pontine arteries in vertebral angiography . Am J Roentgenol 1969 ;106 :296-302 . 7 . Gardner W.I . Concerning the mechanism of the trigeminal neuralgia and hemifacial spasm . J Neurosurg 1962 ;19 :947-58 . 8 . Gardner WJ, Dohn DF . Trigeminal neuralgia-hemifacial spasm-a Paget's disease . Brain 1966 ;89 :555-62 . 9 . Gibson WPR, Wallace D . Basilar artery ectasia . An unusual cause of a cerehello-ponrine lesion and hemifacial spasm . Laryngol Oml 1975 ;89 :''21-31 . 10 . Harsh GR IV, Wilson CB, Hieshima GB, Dillon WP . Magnetic
19. NiizumaH .IkedaS,OhyamaH.Trigeminalneuralgia andhemifacial spasm caused by the compression of tortuous vertebrobasilar system . A case report. No Shinkei Geka 1978 ;6 :1207-12 . 20. Perkin GD, Illingworrh RD . The association of hemifacial spasm and facial pain . J Neurol Neurosurg Psychiatry 1989 ;52 :663-5 . 21 . Pulsinelli WA, Rottenherg DA . Painful tic convulsif. J Neurol Neurosurg Psychiatry 197' ;40 :192-5 . 22 . Takamiya Y, Toya S, Kawase T. Trigeminal neuralgia and hemifacial spasm caused by a tortuous verrebrobasilar system . Surg Neurol 1985 ;24 ;559-562 . 23 . Waga S, Mnr,kawa A, Kojima T . Trigeminal neuralgia : compression of the trigeminal nerve by an elongated and dilatated basilar artery . Surg Neurol 1979 ;11 :13-6 . 24 . Yu Y, Mossley 1, Pullicino P, McDonald W . The clinical picture of ectasia of the intracerebral arteries . .) Neurol Neurosurg Psychiatry 1982 :4529-36.
Surg Neurol 1992 ;38 :232-5
Repositioning of the Tortuous Vertebrobasilar Artery for Trigeminal Neuralgia: A Technical Note Akira Ogawa, M .D., Michiyasu Suzuki, M .D., Reizo Shirane, M.D., and Takashi Yoshimoto, M .D . Division of Neurosurgery, Institute of Brain Diseases, Tohoku University School of Medicine, Sendai, Japan Ogawa A, Suzuki M, Shirane R, Yoshimoto T . Repositioning of the tortuous vertebrobasilar artery for trigeminal neuralgia : a technical note . Surg. Neurol. 1992 ;38 :232-5 . A patient with trigeminal neuralgia caused by a tortuous vertebrobasilar artery is reported . To obtain safe and certain neurovascular decompression of the trigeminal nerve, the tortuous vertebrobasilar artery was repositioned by pulling it toward the dura mater of the clivus using a synthetic vascular slip . The authors describe the technique of repositioning of the tortuous vertebrobasilar artery and its usefulness. KEY WORDS : Hemtfactal spasm ; Neurovascular compression ; Tic convulsi£; Trigeminal neuralgia ; Vertebrobasilar artery
Microvascular decompression, in which a prosthesis is inserted between a vessel and a nerve, is the method of treatment most often chosen for trigeminal neuralgia or hemifacial spasm [12,13] . It has long been known, however, that symptoms may be due not only to neurovascular compression by small intracranial arteries or veins, such as the superior cerebellar artery, the anterior inferior cerebellar artery, or the posterior inferior cerebellar artery, but also to direct compression by a tortuous or elastic vertebrobasilar artery [5] . This kind of disorder is not considered to be rare ; however, operative results are not favorable [1,2,3,7-10,14,15,17-24] . Since the tortuous vertebrobasilar artery is firm and not readily movable, it is not easily decompressed by the insertion of a prosthesis between the artery and the nerve . Although various surgical techniques have been used in such cases, there have been no reports of attempts to relieve the neurovascular compression by means of repositioning the tortuous vertebrobasilar artery itself . We have obtained favorable results using such a technique . The vertebrobasilar artery is repositioned by wrapping it in a
Address reprint requests to: Akira Ogawa, M .D ., Division of Neurosurgery, Institute of Brain Diseases, Tohoku University School of Medicine, 1-1, Sciryo-machi, Aoba-ku, Sendai 980, Japan . Received November 11, 1991 ; accepted February 14, 1992 .
L' 1992 by
Elsevier
Science Publishing Co., Inc .
synthetic slip and pulling it toward the dura mater of the clivus . We describe this technique and our results in this technical note .
Case Report The patient was a 56-year-old man complaining of trigeminal neuralgia of 3 years' duration . Onset was characterized by intermittent pain of the left cheek and twitching of the left orbital region . About I week after onset, neuralgia extended to the entire left side of the face. The twitching of the left orbital region subsided in about 3 months, but he began to experience transient episodes of tinnitus at about that time . A trigger zone for the trigeminal neuralgia was present in the region of the left mouth, and it gradually worsened . About 6 months before hospitalization, he started receiving carbamazepine, but there was no improvement in his symptoms . The pain increased, and it became too painful to wash his face . Other than mild hypertension without treatment, there was nothing notable in his past or family history . No notable neurological findings were obtained at the time of admission . Cerebral angiography disclosed elongation and dilation of the vertebrobasilar artery, tortuousity, and rostral and lateral displacement (Figure LA) . In TI-weighted magnetic resonance imaging (MRI) scans, the course of the vertebrobasilar artery indicated angiographically was depicted as a flow void, and the trigeminal nerve was compressed and displaced rostrally by the basilar artery (Figures 2 and 3A) .
Surgery
A left suboccipital craniotomy was used . To obtain a wide operative field around the vertebrobasilar artery, a craniotomy was performed rostrally to the angle of the transverse sigmoid sinus and caudally to the foramen magnum . The vertebral artery was found directly below the lower cranial nerves . There was no notable arteriosclerosis . The facial and acoustic nerves were compressed and displaced laterally by the vertebral artery . 0090-3019/92/S5A0
Repositioning of Tortuous VBA
Surg Neurol 1992 ;38 :232-5
2 33
Figure 1. Preoperative and postoperatire angiograms ; anterioposterior projection . (A) Preoperative angtogram showing displacement of the tortuous and elongated vertebrobasilar artery (arrowhead) rostrally and laterally . (B) Postoperative angiogram showing repositioning of the tortuous vertebrobasilar artery (arrowheadl caudally and medially . Thedistance between the basilar artery and superior cerebellar artery had widened.
The trigeminal nerve was strongly compressed rostrally by the basilar artery and had become thin . It was determined that using the usual means for inserting a prosthesis between the vessel and the nerve would further aggravate the compression of the trigeminal nerve . Therefore, a synthetic vascular graft (Gore Texu vascular graft) was made into a 6-mm-wide slip and wound around the distal part of the vertebral artery between the acoustic nerve and the glossopharyngeal nerve . This slip was sutured
with 8-0 nylon thread and attached to the vertebral artery . Then, the slip was immobilized on the vertebral artery, and the dura mater of the clivus in the midline portion was sutured using 6-0 nylon thread . The vertebrobasilar artery was pulled in a caudal midline direction, thus relieving the trigeminal, facial, and acoustic nerves from compression by the vertebrobasilar artery (Figure 4) .
Postoperative Course
Figure 2 . Preoperative MR] scan ; 7 I-weighted coronal image (TR 500 net. TE 20 ms) .
Postoperatively, the trigeminal neuralgia was abolished completely without any neurological symptoms . In postoperative angiograms, the rostral and lateral tortuousity of the vertebrobasilar artery was found to have decreased (Figure 2B) . MRI then showed a gap between the trigeminal nerve and flow void of the basilar artery . The displacement of the trigeminal nerve had decreased, and it ran in a straighter course (Figure 3B) . Eighteen months postoperatively, the patient showed no recurrence of any of his symptoms .
Discussion Recently, microvascular decompression has generally been performed for the treatment of trigeminal neuralgia . The vessel responsible for the neurovascular compression is most commonly the superior cerebellar artery, but can also be the anterior inferior cerebellar artery or the intratentorial veins [12] . With such small intracranial arteries or veins, it is normally an easy matter
234
Surg Neurol 1992 ;38: 2 32-5
Ogawa et al
3 . Enhanced Ti-weighted coronal image in the area indicated by Figure 2. (A) Preoperative image depicting the basilar artery as a/low void (arrow displaced rose rally and laterally . The trigeminal nerve (asterisk) is compressed and displaced rostrally by the basilar artery . (B) Postoperative image showing a gap between the trigeminal nerve (asterisk) and the flow enid of the basilar artery (arrmv . The displacement of the trigeminal nerve has decreased, and its course is straighter. Figure
4 . lntraoperative drawing from the left cerebellopontine angle. The synthetic clip immobilized on the vertebral artery was pulled by 6-0 nylon thread toward the dura mater of the clirus . The elongated and tortuous vertebrobasilar artery was moved in a caudal and medial direction, which relieved the trigeminal, facial . and acoustic nerves from compression by the vertebrobasilar artery . A . trigeminal nerve : B, acoustic and facial nerve; arrow, 6-0 nylon thread; asterisk, synthetic clipcropped around and immobilized on the vertebral artery . Figure
000
1
to move the vessel after dissecting it from the surrounding arachnoid membrane. Therefore, alleviation of the compression of nerves by such vessels by placing a prosthesis between them is relatively easy . However, there are also patients with trigeminal neuralgia or facial spasm in whom the responsible vessel is a dilated and tortuous vertebrobasilar artery [1,2,3,7-10,14,15, 17-24). In addition, a number of authors have reported the presence of a tortuous and ectasic vertebrobasilar artery associated with both trigeminal neuralgia and facial spasm (tic convulsif) [2,4,7,8,10,17,19,20) . The present case had both trigeminal neuralgia and facial spasm transiently and is thought to have had a similar cause. For cases in which neurovascular compression is thought to be due to a tortuous and elongated vertebrobasilar artery, intracranial rhizotomy [2,7,8,10,18,23] and thermocoagulation [15,19) have primarily been used, since decompression is not easily performed . There have been some reports of favorable results when neurovascular decompression was accomplished with a prosthesis [17,20] . Satisfactory results have not often been achieved, however, with regard to recurrence and various degree of cranial nerve palsy [4,22] . Because the vertebrobasilar artery is a large artery and is not readily movable, it should be expected that placing a prosthesis between the artery and the nerve will only increase the compression . For this reason, satisfactory results have not been obtained . There have been no reports of attempts at repositioning the vertebrobasilar artery itself to relieve the neurovascular compression . As was clear in the present case, a tortuous vertebrobasilar artery can compress the trigeminal and facial nerves in a rostral and lateral direction, and it is necessary to move the vessel in a mediocaudal direction to obtain effective decompression of the nerves . To move the tortuous and elongated artery without kinking, we use a synthetic slip, winding it around and securing it to the vertebral artery . Then the encircled vertebral artery is pulled upon with nylon thread . In this manner, a tortuous vertebrobasilar artery can be repositioned without kinking, and decompression of the affected nerves can be achieved . The synthetic slip is wound around the distal part of the vertebral artery above the posterior inferior cerebellar artery . In this portion, perforating arteries directly branching from the vertebral artery are rare [6,11,16) . In addition, the perforating branches from the basilar artery to the brain stem can be expected to have been stretched by the displacement of the basilar artery in a rostrolateral direction . Therefore, it is considered unlikely that repositioning in a mediocaudal direction will have any effect on the perforating branches . In fact, comparison of the preoperative and postoperative angiograms and MRI in this
Repositioning
of Tortuous
VBA
Surg Neurol
235
1992 ;38 : 2 3 2 -5
case showed a repositioning
of
the vertebrobasilar ar-
tery . Clinically, there have been no symptoms emia
of the
of
isch-
brain stem, and the previous symptoms dis-
appeared immediately postoperatively .
As
indicated above, to obtain safe and certain neuro-
vascular decompression tery, it
is
of a
tortuous vertebrobasilar ar-
necessary to move the artery in a mediocaudal
direction . Here we have described a technique for the movement
of
an elongated and tortuous artery in the
desired direction without kinking, stenosis, or occlusion, and the favorable results achieved thereby .
resonance imaging of vertebrobasilar ectasia in tic convulsif . A case report. J Neurosurg 1991 ;74 :999-1003 . 11 . Hassler O. Arterial pattern of human brain stem . Normal appearance and deformation in expanding supratentorial conditions . Neurology 1967 ;17 :368-75 . 12 . Janetta PJ . Neurovascular compression in cranial nerve and systemic disease . Ann Surg 1980 ;192 :518-25 . 13 . Janetta PJ, Abbasy M, Maroon JC, Ramos FM, Albin MS. Etiology and definitive microsurgical treatment of hemifacial spasm . Operarive techniques and results in 47 patients . J Neurosurg 1977 ;47 :321-8 . 14 . Kerber CW, Margolis MT, Newton TH . Tortuous vertebrobasilar system : a cause of cranial nerve signs . Neuroradiology 1972 ;4^4-7 . 15 . Lye HL . Basilar artery ectasia : an unusual cause of trigeminal neuralgia. J Neurol Neurosurg Psychiatry 1986 ;49 :22-8 .
References I . Bingas B, Cotsou S . Cerebello-ponrine angle syndrome with uncommon etiology (a case report) . Neuroradiology 1972 ;3 :165-6 .
16. Marmood A, Dujovny M, Torche M, Dragovic L, Austrian JI . Microvascular anatomy of foramen caecum medullare oblongarae. J Neurosurg 1991 ;75 :299-304 .
2 . Campbell E, Keedy C . Hemifacial spasm: a note on the etiology in two cases . J Neurosurg 1947 ;4 :342-7 .
17 . Miyagi J, Hanabusa Y, Kuramoto S, Kubuyama M, Kajiwara K . Neurovascular decompression for trigeminal neuralgia associated with hemifacial spasm . Neurol Med Chic (Tokyo) 1986 ;26 :900-3 .
3 . Carella A, Caruso G, Lamberti P . Hemifacial spasm due to elongation of the distal segment of the vertebral artery . Report of two cases . Neuroradiology 1973 ;6 :233-6 .
18 . Nergoy DR, Dohn DF . Hemifacial spasm secondary to vascular compression of the facial nerve . Cleve Clin Q 1974 ;41 :205-14 .
4 . Cook BR, Janetta PJ . Tic convulsif : results in I I cases treated with microvascular decompression of the fifth and seventh cranial nerves . J Neurosurg 1984 ;61 :949-51 . 5 . Dandy WE . Concerning the cause of trigeminal neuralgia . Am J Surg 1934 ;24 :445-55 . 6 . Gabrielsen TO, Amundsen P. The pontine arteries in vertebral angiography . Am J Roentgenol 1969 ;106 :296-302 . 7 . Gardner W.I . Concerning the mechanism of the trigeminal neuralgia and hemifacial spasm . J Neurosurg 1962 ;19 :947-58 . 8 . Gardner WJ, Dohn DF . Trigeminal neuralgia-hemifacial spasm-a Paget's disease . Brain 1966 ;89 :555-62 . 9 . Gibson WPR, Wallace D . Basilar artery ectasia . An unusual cause of a cerehello-ponrine lesion and hemifacial spasm . Laryngol Oml 1975 ;89 :''21-31 . 10 . Harsh GR IV, Wilson CB, Hieshima GB, Dillon WP . Magnetic
19. NiizumaH .IkedaS,OhyamaH.Trigeminalneuralgia andhemifacial spasm caused by the compression of tortuous vertebrobasilar system . A case report. No Shinkei Geka 1978 ;6 :1207-12 . 20. Perkin GD, Illingworrh RD . The association of hemifacial spasm and facial pain . J Neurol Neurosurg Psychiatry 1989 ;52 :663-5 . 21 . Pulsinelli WA, Rottenherg DA . Painful tic convulsif. J Neurol Neurosurg Psychiatry 197' ;40 :192-5 . 22 . Takamiya Y, Toya S, Kawase T. Trigeminal neuralgia and hemifacial spasm caused by a tortuous verrebrobasilar system . Surg Neurol 1985 ;24 ;559-562 . 23 . Waga S, Mnr,kawa A, Kojima T . Trigeminal neuralgia : compression of the trigeminal nerve by an elongated and dilatated basilar artery . Surg Neurol 1979 ;11 :13-6 . 24 . Yu Y, Mossley 1, Pullicino P, McDonald W . The clinical picture of ectasia of the intracerebral arteries . .) Neurol Neurosurg Psychiatry 1982 :4529-36.
