The Jugular Dural Fold—A Helpful Skull Base Landmark to the Cranial Nerves

During a retrosigmoid (or combined retrolabyrinthine-retrosigmoid) approach to the posterior fossa for vestibular neurectomy or removal of small acoustic neuromas, a white dural fold is a consistent landmark to cranial nerves VII through XII. This fold of dura appears as a white linear structure extending from the foramen magnum across the sigmoid sinus, attaching to the posterior aspect of the temporal bone, anterior to the vestibular aqueduct. The name “jugular dural fold” is suggested for this landmark. The jugular dural fold overlies the junction of the sigmoid sinus and the jugular foramen. As measured in formalin-fixed cadaver heads, the overall length of the jugular dural fold is 20.8 mm (± 2.9 mm). The cochleovestibular nerve lies 9.9 mm (± 1.5 mm) anterior to the superior aspect of the jugular dural fold, the glossopharyngeal nerve lies 9.5 mm (± 1.6 mm) anterior to the midpoint of the jugular dural fold, and the operculum of the vestibular aqueduct lies 6.6 mm (± 0.7 mm) posterior to the jugular dural fold. Intraoperative measurements in patients undergoing combined retrolabyrinthine-retrosigmoid vestibular neurectomy show an overall length of the jugular dural fold of 16.3 mm (± 1.9 mm). The cochleovestibular nerve lies 8.6 mm (± 1.3 mm) anterior to the superior aspect of the jugular dural fold, the glossopharyngeal nerve lies 8.6 mm (± 1.3 mm) anterior to the midpoint of the jugular dural fold, and the operculum lies 7.5 mm (± 0.8 mm) posterior to the jugular dural fold. The jugular dural fold can be used as a reliable landmark for rapidly locating cranial nerves in the posterior fossa.     

Microsurgical Posterior Fossa Vestibular Neurectomy: An Evolution in Technique

Between 1925 and 1945, Walter Dandy and Kenneth McKenzie performed more than 700 posterior fossa eighth nerve sections and vestibular neurectomies, treating the intractable vertigo accompanying Meniere's disease. During the past 10 years, using microsurgical techniques and reaching the posterior fossa through the temporal bone, vestibular neurectomy has enjoyed a resurgence of popularity. When hearing is to be preserved, vestibular neurectomy is the surgical treatment of choice, if the patient fails to undergo a remission of the vertigo of Meniere's disease. This report reviews 115 consecutive vestibular neurectomies performed for the treatment of Meniere's disease from 1978 to 1988.

In 1978, the retrolabyrinthine vestibular neurectomy (RVN) was introduced, a procedure in which the posterior fossa is entered anterior to the sigmoid sinus and behind the labyrinth. During the last three years, the approach to the posterior fossa has been a small dural opening behind the sigmoid sinus, the combined retrolabyrinthine-retrosigmoid (R-R) approach. There have been no cases of facial paralysis and no serious complications. A high incidence of headache (75%) resulted when the posterior wall of the internal auditory canal was drilled away for better exposure. Transient cerebrospinal fluid (CSF) leaks occurred in 7% of the patients having the RVN, the incidence was 3% when the combined R-R approach was used. In the RVN series, wound infection occurred in 20% of cases until perioperative antibiotics reduced the rate to 3%. The results in curing or improving vertigo have been excellent (94%), and hearing has been preserved to within 20 dB of the preoperative levels in 76%. Until a cure for Meniere's disease is found, microsurgical posterior fossa vestibular neurectomy remains the best treatment.

     

Combined retrolabyrinthine-retrosigmoid approach for improved exposure of the posterior fossa without cerebellar retraction

The combined retrolabyrinthine-retrosigmoid (CRR) approach utilizes anterior retraction of the sigmoid sinus to improve exposure of the posterior fossa without cerebellar retraction. The CRR was initially used for vestibular neurectomy but is now utilized for acoustic neuroma excision with hearing preservation and exposure for clipping of basilar and vertebrobasilar aneurysms. This excellent exposure of the cerebellopontine angle without cerebellar retraction can be used for all posterior fossa exposures.     

Combined Retrolabyrinthine-Retrosigmoid Approach for Improved Exposure of the Posterior Fossa Without Cerebellar Retraction

The combined retrolabyrinthine-retrosigmoid (CRR) approach utilizes anterior retraction of the sigmoid sinus to improve exposure of the posterior fossa without cerebellar retraction. The CRR was initially used for vestibular neurectomy but is now utilized for acoustic neuroma excision with hearing preservation and exposure for clipping of basilar and vertebrobasilar aneurysms. This excellent exposure of the cerebellopontine angle without cerebellar retraction can be used for all posterior fossa exposures.     

The unrecognized rotation of the vestibular and cochlear nerves from the labyrinth to the brain stem: its implications to surgery of the eighth cranial nerve

The cochlear and vestibular nerves rotate 90 degrees from the inner ear to the brain stem. Most of the rotation occurs within the internal auditory canal (IAC); only minimal rotation occurs in the cerebellopontine (CP) angle. At the labyrinthine end of the IAC, the cochlear nerve--which at first lies anterior to the inferior vestibular nerve (saccular nerve)--rapidly fuses with the inferior vestibular nerve. It then rotates to become inferior as the nerves leave the porus acousticus. The cochleovestibular (C-V) cleavage plane lies in a superior-inferior direction in the lateral IAC and rotates to become anterior-posterior in the CP angle. In 25% of patients in whom no C-V cleavage plane can be seen, it is not possible to completely transect all vestibular fibers. The surgical implications are that the most complete vestibular neurectomy can be done only in the lateral IAC, the cochlear and inferior vestibular nerves, because of their intimate association, should not be separated in the mid-IAC, in order to prevent damage to the cochlear nerve, and to create a complete denervation of the vestibular labyrinth, only the posterior ampullary nerve along with the superior vestibular nerve should be transected.     

Microsurgical posterior fossa vestibular neurectomy: an evolution in technique

Between 1925 and 1945, Walter Dandy and Kenneth McKenzie performed more than 700 posterior fossa eighth nerve sections and vestibular neurectomies, treating the intractable vertigo accompanying Meniere's disease. During the past 10 years, using microsurgical techniques and reaching the posterior fossa through the temporal bone, vestibular neurectomy has enjoyed a resurgence of popularity. When hearing is to be preserved, vestibular neurectomy is the surgical treatment of choice, if the patient fails to undergo a remission of the vertigo of Meniere's disease. This report reviews 115 consecutive vestibular neurectomies performed for the treatment of Meniere's disease from 1978 to 1988.In 1978, the retrolabyrinthine vestibular neurectomy (RVN) was introduced, a procedure in which the posterior fossa is entered anterior to the sigmoid sinus and behind the labyrinth. During the last three years, the approach to the posterior fossa has been a small dural opening behind the sigmoid sinus, the combined retrolabyrinthine-retrosigmoid (R-R) approach. There have been no cases of facial paralysis and no serious complications. A high incidence of headache (75%) resulted when the posterior wall of the internal auditory canal was drilled away for better exposure. Transient cerebrospinal fluid (CSF) leaks occurred in 7% of the patients having the RVN, the incidence was 3% when the combined R-R approach was used. In the RVN series, wound infection occurred in 20% of cases until perioperative antibiotics reduced the rate to 3%. The results in curing or improving vertigo have been excellent (94%), and hearing has been preserved to within 20 dB of the preoperative levels in 76%. Until a cure for Meniere's disease is found, microsurgical posterior fossa vestibular neurectomy remains the best treatment.     

The singular canal: a valuable landmark in surgery of the internal auditory canal

The singular canal transmits the posterior ampullary nerve between the inferior part of the internal auditory canal (IAC) and ampulla of the posterior semicircular canal. The anatomy of the singular canal was studied in temporal bone dissections, in surgical dissections, and in high-resolution computerized tomography scans. Measurements were taken for distances between the origin of the singular canal in the IAC, the porus acousticus, the vestibule, and posterior canal ampulla. The location and importance of the singular canal are demonstrated for retrosigmoid-IAC vestibular neurectomy, retrosigmoid acoustic neuroma surgery, and transcochlear cochleovestibular neurectomy. The main purpose for the use of the retrosigmoid approach to the internal auditory canal during vestibular neurectomy and excision of acoustic neuromas is preservation of hearing. A major concern when the contents of the internal auditory canal are exposed through this approach is fenestration of the labyrinth, which results in sensorineural hearing loss. In the retrosigmoid approach, the singular canal has been found to be a vital landmark in prevention of fenestration during surgery of the internal auditory canal.     

The resurrection of vestibular neurectomy: a 10-year experience with 115 cases

Between 1925 and 1945, Walter Dandy and Kenneth McKenzie performed more than 700 posterior fossa eighth nerve sections and vestibular neurectomies to treat the intractable vertigo accompanying Ménière's disease. During the past 10 years, with the aid of microsurgical techniques and the approach to the posterior fossa through the temporal bone, vestibular neurectomy has undergone a resurgence of popularity. When hearing is to be preserved, vestibular neurectomy is the surgical treatment of choice for patients who fail to undergo a remission of the vertigo attacks of Ménière's disease. This report reviews 115 consecutive vestibular neurectomies performed from 1978 to 1988 for the treatment of Ménière's disease. In 1978, retrolabyrinthine vestibular neurectomy (RVN), a procedure in which the posterior fossa is entered anterior to the sigmoid sinus and behind the labyrinth, was introduced. During the last 3 years, the approach to the posterior fossa has been a small dural opening behind the sigmoid sinus; this approach is known as the combined retrolabyrinthine retrosigmoid approach. There have been no cases of facial paralysis and no serious complications connected with this technique. A high incidence of headache (50%) resulted when the posterior wall of the internal auditory canal was drilled away for better exposure. Transient cerebrospinal fluid (CSF) leaking occurred in 7% of the patients undergoing RVN; however, no CSF leaks occurred when the combined retrolabyrinthine retrosigmoid approach was used. In the RVN series, wound infection occurred in 20% of the cases until perioperative antibiotics reduced the rate to 3%. The results in terms of curing or improving vertigo have been excellent (94%), and hearing has been preserved to within 20 dB preoperative levels in 76% of the cases. Until a cure for Ménière's disease is found, microsurgical posterior fossa vestibular neurectomy remains the best treatment.     

Anatomic landmarks of the glossopharyngeal nerve: a microsurgical anatomic study

OBJECTIVE: Compared with other lower cranial nerves, the glossopharyngeal nerve (GPhN) is well hidden within the jugular foramen, at the infratemporal fossa, and in the deep layers of the neck. This study aims to disclose the course of the GPhN and point out landmarks to aid in its exposure. METHODS: The GPhN was studied in 10 cadaveric heads (20 sides) injected with colored latex for microsurgical dissection. The specimens were dissected under the surgical microscope. RESULTS: The GPhN can be divided into three portions: cisternal, jugular foramen, and extracranial. The rootlets of the GPhN emerge from the postolivary sulcus and course ventral to the flocculus and choroid plexus of the lateral recess of the fourth ventricle. The nerve then enters the jugular foramen through the uppermost porus (pars nervosa) and is separated from the vagus and accessory nerves by a fibrous crest. The cochlear aqueduct opens to the roof of this porus. On four sides in the cadaver specimens (20%), the GPhN traversed a separate bony canal within the jugular foramen; no separate canal was found in the other cadavers. In all specimens, the Jacobson's (tympanic) nerve emerged from the inferior ganglion of the GPhN, and the Arnold's (auricular branch of the vagus) nerve also consisted of branches from the GPhN. The GPhN exits from the jugular foramen posteromedial to the styloid process and the styloid muscles. The last four cranial nerves and the internal jugular vein pass through a narrow space between the transverse process of the atlas (C1) and the styloid process. The styloid muscles are a pyramid shape, the tip of which is formed by the attachment of the styloid muscles to the styloid process. The GPhN crosses to the anterior side of the stylopharyngeus muscle at the junction of the stylopharyngeus, middle constrictor, and hyoglossal muscles, which are at the base of the pyramid. The middle constrictor muscle forms a wall between the GPhN and the hypoglossal nerve in this region. Then, the GPhN gives off a lingual branch and deepens to innervate the pharyngeal mucosa. CONCLUSION: Two landmarks help to identify the GPhN in the subarachnoid space: the choroid plexus of the lateral recess of the fourth ventricle and the dural entrance porus of the jugular foramen. The opening of the cochlear aqueduct, the mastoid canaliculus, and the inferior tympanic canaliculus are three landmarks of the GPhN within the jugular foramen. Finally, the base of the styloid process, the base of the styloid pyramid, and the transverse process of the atlas serve as three landmarks of the GPhN at the extracranial region in the infratemporal fossa.     

Transsigmoid Approach for Tumors of the Jugular Foramen

A transsigmoid approach is detailed for removal of tumors involving the jugular foramen. This approach was used in seven patients, eliminates the need for facial nerve transposition, and helps to preserve cochleovestibular function. The sigmoid sinus is packed and both the facial nerve and the labyrinth are identified. This approach provides excellent vision of the intradural and extradural course of the lower cranial nerves, rendering preservation of isolated nerves within the neural compartment feasible.     

Ossification of the Posterior Petroclinoid Dural Fold: A Cadaveric Study with Neurosurgical Significance

Objectives The roof of the porus trigeminus, composed of the posterior petroclinoid dural fold, is an important landmark to the skull base surgeon. Ossification of the posterior petroclinoid dural fold is an anatomical variation rarely mentioned in the literature. Such ossification results in the trigeminal nerve traversing a bony foramen as it enters Meckel cave. The authors performed this study to better elucidate this anatomical variation. Design Fifteen adult cadaveric head halves were subjected to dissection of the middle cranial fossa. Microdissection techniques were used to examine the posterior petroclinoid dural folds. Skull base osteology was also studied in 71 dry human skulls with attention paid to the attachment point of the posterior petroclinoid dural folds at the trigeminal protuberances. Setting Cadaver laboratory Main Outcome Measures Measurements were made using a microcaliper. Digital images were made of the dissections. Results Completely ossified posterior petroclinoid folds were present in 20% of the specimens. Of the 142 dry skull sides examined, 9% had large trigeminal protuberances. Conclusions Based on this study, the posterior petroclinoid dural fold may completely ossify in adults that may lead to narrowing of the porus trigeminus and potential compression of the trigeminal nerve at the entrance to Meckel cave.     

Transsigmoid approach for tumors of the jugular foramen

A transsigmoid approach is detailed for removal of tumors involving the jugular foramen. This approach was used in seven patients, eliminates the need for facial nerve transposition, and helps to preserve cochleovestibular function. The sigmoid sinus is packed and both the facial nerve and the labyrinth are identified. This approach provides excellent vision of the intradural and extradural course of the lower cranial nerves, rendering preservation of isolated nerves within the neural compartment feasible.     

内镜辅助下经乳突颈静脉球手术入路的显微解剖

目的 探讨颈静脉球部位的手术入路.方法 应用15具(30侧)成人头颅标本,模拟内镜辅助下经乳突颈静脉球手术,观察手术入路中主要结构及颈静脉球部位的暴露情况.结果 颈静脉球到面神经垂直段的距离为(3.58±1.32)mm;颈静脉球前壁到面神经垂直段的距离为(5.07±2.93)mm;颈静脉球顶到后半规管距离为(4.68±3.47)mm;颈静脉球顶到鼓室底壁的距离为(0.14±4.32)mm:30例颞骨标本中,5例颈静脉球顶位于鼓室下方,面神经垂直段前方;16例位于面神经垂直段内侧鼓室后方,面神经位于颈静脉球顶部的中间位置;7例位于鼓室和面神经后;2例们于面神经前鼓室底壁内侧接近内耳道下壁.应用内镜辅助能够在面神经垂直段后暴露颈静脉球部位,清楚的显示颈静脉球内侧壁的后组颅神经与血管,并且能够显示脑神经出颅进入颈静脉球的部位.结论 内镜辅助下经乳突入路切除颈静脉球部位病变,损伤较小,利于保留面、听神经功能及后组脑神经功能.     

Microsurgical Anatomy for Lateral Approaches to the Foramen Magnum with Special Reference to Transcondylar Fossa (Supracondylar Transjugular Tubercle) Approach

Microsurgical anatomy for lateral approaches to the foramen magnum, especially for transcondylar fossa (supracondylar transjugular tubercle) approach, was studied using cadavers. The transcondylar fossa approach is an approach in which extradural removal of the posterior portion of the jugular tubercle through the condylar fossa is added to the far lateral approach. Some differences between this approach and the transcondylar approach are demonstrated. The atlanto-occipital joint and the jugular tubercle are obstacles for the lateral approaches. The condylar fossa forming the external occipital surface of the jugular tubercle is located supero-posterior to the occipital condyle. The fossa is limited laterally by the sigmoid sulcus and the jugular foramen. The posterior condylar canal communicating anteriorly with the distal end of the sigmoid sulcus, the jugular foramen, or the hypoglossal canal opens at the bottom of the fossa. The condyle is situated inferior to the posterior condylar and hypoglossal canals, and the jugular tubercle is located superior to them. In the transcondylar fossa approach the posterior part of the jugular tubercle is extradurally removed, but the condyle and the atlanto-occipital joint are untouched. On the other band, in the transcondylar approach the medial parts of the condyle and the lateral mass of Cl are removed. The latter approach offers better visualization of the inferior part of the foramen magnum. The essential difference of the two approaches is in the direction of looking and the extent of resection of the atlanto-occipital joint. Both approaches offer excellent view of the ventral dural space in the lower clivus and the foramen magnum, but the level of exposure differs somewhat between them. In the lateral approaches to the foramen magnum, the condylar fossa, the posterior condylar canal, and the posterior condylar emissary vein all play an important role as intraoperative anatomical landmarks.     

Microsurgical anatomy for lateral approaches to the foramen magnum with special reference to transcondylar fossa (supracondylar transjugular tubercle) approach

Microsurgical anatomy for lateral approaches to the foramen magnum, especially for transcondylar fossa (supracondylar transjugular tubercle) approach, was studied using cadavers. The transcondylar fossa approach is an approach in which extradural removal of the posterior portion of the jugular tubercle through the condylar fossa is added to the far lateral approach. Some differences between this approach and the transcondylar approach are demonstrated. The atlanto-occipital joint and the jugular tubercle are obstacles for the lateral approaches. The condylar fossa forming the external occipital surface of the jugular tubercle is located supero-posterior to the occipital condyle. The fossa is limited laterally by the sigmoid sulcus and the jugular foramen. The posterior condylar canal communicating anteriorly with the distal end of the sigmoid sulcus, the jugular foramen, or the hypoglossal canal opens at the bottom of the fossa. The condyle is situated inferior to the posterior condylar and hypoglossal canals, and the jugular tubercle is located superior to them. In the transcondylar fossa approach the posterior part of the jugular tubercle is extradurally removed, but the condyle and the atlanto-occipital joint are untouched. On the other band, in the transcondylar approach the medial parts of the condyle and the lateral mass of Cl are removed. The latter approach offers better visualization of the inferior part of the foramen magnum. The essential difference of the two approaches is in the direction of looking and the extent of resection of the atlanto-occipital joint. Both approaches offer excellent view of the ventral dural space in the lower clivus and the foramen magnum, but the level of exposure differs somewhat between them. In the lateral approaches to the foramen magnum, the condylar fossa, the posterior condylar canal, and the posterior condylar emissary vein all play an important role as intraoperative anatomical landmarks.     

Surgical approach for jugular foramen neurinoma--combined suboccipital and infralabyrinthine approach using a rotatable head holder

A 36-year-old male with jugular foramen neurinoma was operated upon using a rotatable head holder, which enables the surgeon to rotate the patient's head at any time during the procedure and to gain access in multiple directions to the tumor. The tumor was situated primarily in the jugular foramen and showed partial extension into intracranial as well as into extracranial space. The patient was placed in the lateral position with a rotatable head holder, which allows rotation of the patient's head with the range of 10 degrees face up to 80 degrees face down from the horizontal plane. A linear skin incision was made, beginning behind the auricle and extending along the anterior margin of the sternocleidomastoid muscle, and the sternocleidomastoid muscle was divided just below the tip of the mastoid process. During mastoidectomy and suboccipital craniectomy, the patient's head was rotated 15 degrees face down and sigmoid sinus was exposed toward the jugular foramen, meanwhile the posterior fossa dura mater was opened and the intracranial portion of the tumor was removed with the head positioned 45 degrees-60 degrees face down. The patient's head is then turned 30 degrees face down and the facial canal was opened to displace the facial nerve forward. This oblique posterior approach minimized facial nerve displacement and provided excellent exposure of the large tumor rest which was situated mainly in the jugular foramen and partly extended extracranially. The rotatable head holder allows excellent access in multiple directions and is very helpful in approaching to jugular foramen neurinomas which grow primarily in the jugular foramen and extend both into intra- and extracranially.     

Meningioma of the accessory nerve extending from the jugular foramen into the parapharyngeal space

Summary A 35-year-old man presented with pain in the right shoulder and neck for 18 months. The neurological examination revealed complete accessory nerve palsy on the right side without further deficits. Magnetic resonance imaging showed a right parapharyngeal tumour expanding into the posterior fossa through the jugular foramen without dural attachment and absence of invasion into the middle ear cavity or internal auditory meatus. Intraoperative inspection disclosed a tumour originating from the accessory nerve. Histological diagnosis revealed a meningothelial meningioma with invasion of the epineural space. To the knowledge of the authors this is the first report of an accessory nerve meningioma in the jugular foramen associated with a posterior fossa component and extension into the parapharyngeal space.     

The jugular foramen: A comparative radioanatomic study

BACKGROUND Advances in microsurgical techniques made possible the removal of advanced jugular foramen (JF) lesions, which once had been accepted as unoperable. However, successful surgery requires detailed knowledge of the JF anatomy.

METHODS Sixteen jugular foramina in eight formalin-preserved adult cadavers were scanned with axial and coronal high resolution computed tomography (HRCT) prior to dissection. After craniectomy and removal of brain tissue, the relationships of the neurovascular structures in the JF were determined by drilling the temporal bones from superior to inferior on planes parallel to the skull base.

RESULTS No bony partition of the JF was observed. A dural band consistently divided the JF into two parts. Anterior to it was the glossopharyngeal nerve (IX) while the vagus (X) and accessory (XI) nerves were located posteriorly. There was a notch in which the IX nerve entered the JF. It was also identified on the CT scans and defined as the glossopharyngeal recess. The IX nerve made a genu within the JF in all specimens. Then, it ran inferiorly through a bony canal in three specimens (18.75%), and through an incomplete bony canal in two (12.5%), which were also defined on the CT images. The inferior petrosal sinus ran through a sulcus anteromedial to the glossopharyngeal recess. The posterior meningeal artery was found to be located between the X and XI nerves within the JF.

CONCLUSIONS This study revealed a complex and highly variable pattern of the relationships of the neurovascular structures in the JF, and their HRCT images correlated well with the anatomic microdissections.     

Jugular foramen: microscopic anatomic features and implications for neural preservation with reference to glomus tumors involving the temporal bone

OBJECTIVE: Our goals were to study the normal histological features of the jugular foramen, compare them with the histopathological features of glomus tumors involving the temporal bone, and thus provide insight into the surgical management of these tumors with respect to cranial nerve function. METHODS: Ten jugular foramen blocks were obtained from five human cadavers after removal of the brain. Microscopic studies of these blocks were performed, with particular attention to fibrous or bony compartmentalization of the jugular foramen, the relationships of the caudal cranial nerves to the jugular bulb/jugular vein and internal carotid artery, and the fascicular structures of the nerves. In addition, we studied the histopathological features of 11 glomus tumors involving the temporal bone (10 patients), with respect to nerve invasion, associated fibrosis, and carotid artery adventitial invasion. RESULTS: A dural septum separating the IXth cranial nerve from the fascicles of Cranial Nerves X and XI, at the intracranial opening, was noted. Only two specimens, however, had a septum (one bony and one fibrous) producing internal compartmentalization of the jugular foramen. The cranial nerves remained fasciculated within the foramen, with the vagus nerve containing multiple fascicles and the glossopharyngeal and accessory nerves containing one and two fascicles, respectively. All of these nerve fascicles lay medial to the superior jugular bulb, with the IXth cranial nerve located anteriorly and the XIth cranial nerve posteriorly. All nerve fascicles had separate connective tissue sheaths. A dense connective tissue sheath was always present between the IXth cranial nerve and the internal carotid artery, at the level of the carotid canal. The inferior petrosal sinus was present between the IXth and Xth cranial nerves, as single or multiple venous channels. The glomus tumors infiltrated between the cranial nerve fascicles and inside the perineurium. They also produced reactive fibrosis. In one patient, in whom the internal carotid artery was also excised, the tumor invaded the adventitia. CONCLUSION: Within the jugular foramen, the cranial nerves lie anteromedial to the jugular bulb and maintain a multifascicular histoarchitecture (particularly the Xth cranial nerve). Glomus tumors of the temporal bone can invade the cranial nerve fascicles, and infiltration of these nerves can occur despite normal function. In these situations, total resection may not be possible without sacrifice of these nerves.     

Selective percutaneous thermocoagulation of the glossopharyngeal nerve in intractable glossopharyngeal neuralgia

Percutaneous radiofrequency thermocoagulation of glossopharyngeal nerve at the jugular foramen was employed for the treatment of intractable glossopharyngeal neuralgia in three cases, one with essential and two with symptomatic pain from malignant tumor of the oropharyngeal area. Under radiological control, the thermocoagulation electrode was inserted through the lateral cervical route, and the electrode reached the jugular foramen with the tip toward the pars nervosa. The correct position of the electrode was confirmed by radiography and by electrophysiological stimulation test. Once the electrode was properly positioned, lesion was made with temperature of 60 degrees C to 70 degrees C for 1 approximately 2 minutes. Surgical results were satisfactory and no neurological and cardiovascular complications were noted. Percutaneous radiofrequency thermocoagulation of glossopharyngeal nerve is thought to be very useful for the treatment of intractable glossopharyngeal neuralgia.