The Laryngoscope Lippincott Williams & Wilkins, Inc. © 2006 The American Laryngological, Rhinological and Otological Society, Inc.

Surgical Management of Jugular Foramen Schwannomas With Hearing and Facial Nerve Function Preservation: A Series of 23 Cases and Review of the Literature Mario Sanna, MD; Andrea Bacciu, MD; Maurizio Falcioni, MD; Abdelkader Taibah, MD

Objective: Schwannomas of the jugular foramen are rare lesions and controversy regarding their management still exists. The objective of this retrospective study was to analyze the management and outcome in a series of 23 cases collected at a single center. Setting: This study was conducted at a quaternary private otology and skull base center. Methods: Charts belonging to patients with a diagnosis of jugular foramen schwannoma attending our center between May 1988 and April 2006 were examined retrospectively. Results: The study group consisted of 23 patients. One patient (a 73-year-old woman) with normal lower cranial nerves function was managed with watchful expectancy and regular clinical and radiologic follow ups. The infratemporal fossa approach– type A (IFTA-A) was performed in 3 cases. One patient underwent a transcochlear–transjugular approach. Of the 22 patients surgically treated, 12 patients were operated on by the petrooccipital transsigmoid approach (POTS). In one patient with a preoperative dead ear, a combined POTS–translabyrinthine approach was adopted. Two patients were operated on through the POTS approach combined with the transotic approach. In another case (a 67-year-old woman), a subtotal tumor removal through a transcervical approach was planned to resect a 10-cm mass in the neck. One patient underwent a first-stage combined transcervical–subtotal petrosectomy approach to remove a huge tumor in the neck; the second-stage intradural removal of the tumor was accomplished through a translabyrinthine–transsigmoid–transjugular approach. The last patient underwent a first-stage combined transcervical–subtotal From Gruppo Otologico (M.S., M.F., A.T.), Piacenza–Rome, Rome, Italy; and the Department of Otolaryngology (A.B.), University of Parma, Parma, Italy. Editor’s Note: This Manuscript was accepted for publication September 6, 2006. Supported by a grant from Associazione Italiana Neuro-Otologica (AINOT). Send correspondence to Mario Sanna, Otology, Neurotology and Skull Base Surgery, Gruppo Otologico, Via Emmanueli 42, 29100 Piacenza, Italy. E-mail: [email protected] DOI: 10.1097/01.mlg.0000246193.84319.e5

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petrosectomy approach to remove the neck tumor component; this patient is now waiting for the second-stage intradural removal of the tumor. Complete tumor removal was accomplished in 21 cases and in one case, a residual schwannoma was left in place in the area of the jugular foramen. The 3 patients who were operated on by IFTA-A underwent permanent anterior transposition of the facial nerve. At 1-year follow up, 2 of these patients had HouseBrackmann grade I and 1 reached grade IV. The patient who underwent a transcochlear–transjugular approach had a permanent posterior transposition of the facial nerve. At 1-year follow up, he had grade III facial nerve function. Postoperative facial nerve function was normal (House-Brackmann grade I) in all patients operated on by the POTS approach. Twelve patients had hearing-preserving surgery using the POTS approach. Good hearing was preserved in 10 cases (83.3%), the majority of whom (58.3%) maintained their preoperative hearing level. There was no perioperative mortality. One patient (4.5%) experienced a postoperative cerebrospinal fluid leak. After surgery, all patients did not recover the function of the preoperatively paralyzed lower cranial nerves. A new deficit of one or more of the lower cranial nerves was recorded in 50% of cases. So far, no patient has experienced recurrence during the follow-up period as ascertained by computed tomography or magnetic resonance imaging. Conclusions: Surgical resection is the treatment of choice for jugular foramen schwannomas. The POTS approach allowed single-stage, total tumor removal with preservation of the facial nerve and of the middle and inner ear functions in the majority of cases. Despite the advances in skull base surgery, new postoperative lower cranial nerve deficits still represent a challenge. Key Words: Jugular foramen schwannoma, surgical management, hearing preservation, facial nerve preservation. Laryngoscope, 116:2191–2204, 2006

INTRODUCTION Jugular foramen schwannomas (JFSs) arising from cranial nerves (CNs) IX, X, and XI are rare, slowly growing benign tumors that constitute approximately 2.9% to Sanna et al.: Jugular Foramen Schwannoma

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4% of all intracranial schwannomas.1,2 During the past 30 years, there has been a dramatic rise in the number of reports,1–9 although the majority of the articles still present case reports. This increase may be attributed to enhanced physician awareness and the improvements in imaging techniques. However, less than 200 cases are reported in the English literature. It has been hypothesized that JFSs may originate from the ganglia of CNs IX and X, which are all situated close to the jugular foramen. However, the exact nerve of origin remains for the most part unknown. Following the path of least resistance, these tumors may expand through the perijugular skull base, superiorly into the posterior fossa cistern, or inferiorly into the parapharyngeal space. The dumbbellshaped tumors have both intracranial and cervical extension with a component in the jugular foramen.10 The ideal primary treatment of these tumors is total surgical removal. The management of these lesions is particularly challenging as a result of the complex anatomic location and potential postoperative complications. In fact, the jugular foramen area was not completely under surgeon control until the introduction of the infratemporal fossa approach–type A (IFTA-A) by Ugo Fisch in 1978.11 Different surgical approaches have been subsequently proposed and modified for dealing with JFSs.2,5–7,12,13 The fact that many such patients have normal hearing and facial nerve function tempts the surgeon to choose an approach that preserves hearing and facial nerve function without hampering adequate tumor visualization and control. The petrooccipital transsigmoid (POTS) approach, introduced by Mann et al. in 1991 and modified by Mazzoni and Sanna in 1995,12 has been successfully adopted in our center over the last few years. This approach offers direct access to the jugular foramen area, cerebellopontine angle, and upper cervical region with preservation of the middle and inner ear without the need for facial nerve transposition, as is required by the IFTA-A. This study reports the experience of the Gruppo Otologico, Piacenza–Rome, in the management of 23 patients with a diagnosis of JFS, 22 of whom underwent surgery. The article discusses the presenting symptoms, operative procedures, location and extent of the tumor, hearing and facial nerve function results, and postoperative outcome as well as offering a review of the literature.

blood flow of the sigmoid sinus and jugular bulb. All underwent flexible fiberoptic laryngoscopy and hearing assessment by puretone audiometry. Tumors were graded according to Sami et al. and Pellet et al. modification of Kaye et al.’s classification3 (Table I). The facial nerve function was graded according to the House-Brackmann (HB) scale. Lower CN monitoring was not used on a regular basis. Hearing results were evaluated according to the modified Sanna’s classification (Table II). Pure-tone average was calculated as the mean of 500, 1,000, 2,000, and 4,000 thresholds. The follow up (consisting of clinical evaluation, hearing tests, flexible fiberoptic laryngoscopy, and serial CT and/or MRI scans) of the series ranged from 3 to 168 months (mean, 36.6 ⫾ 40.3 months).

RESULTS General Characteristics The study group was composed of 23 patients with JFS. There were 11 (47.8%) females and 12 (52.6%) males. The mean age of the patients was 43 ⫾ 13.6 years (range, 26 –73 years). Fourteen (60.9%) tumors were on the left side and 9 (39.1%) on the right side. No patients had evidence of neurofibromatosis type 2. One patient (a 73year-old woman) with normal lower CN function was managed with watchful expectancy and regular clinical and radiologic follow ups. The relevant patient demographic characteristics, location of the tumor, specific operative approaches used for each case, and outcomes for the 22 surgically treated patients are listed in Table III.

Clinical Manifestations Dysphonia and dysphagia were the most common presenting complaints, occurring in 11 (47.8%) and 10 (43.7%) patients, respectively. Signs and symptoms at the time of presentation are summarized in Table IV. The mean length of symptoms previous to presentation was 9.6 ⫾ 8.7 months (range, 1–24 months). On otoscopic examination, one patient was found to have a retrotympanic mass (case no. 3) and one patient had a polypoid mass extending into the external auditory canal (case no. 1).

Location of the Tumor and Tumor Origin The location and the extent of the lesions were determined preoperatively using the radiology reports (HRCT with bone windows and MRI Gd), which was subsequently confirmed intraoperatively. The frequency of involvement of the various structures was as follows: jugular foramen, 22 (100%); cerebellopontine angle, 20 (91%); upper neck, 19 (86.3%); middle ear, 2 (9%); mastoid, 2 (9%); and external

MATERIALS AND METHODS The charts belonging to patients with a diagnosis of JFS and who attended the Gruppo Otologico Piacenza–Rome between May 1988 and April 2006 were examined retrospectively. Schwannomas of the lower CNs with no jugular foramen involvement were excluded from the study. The collected data were analyzed for age, sex, presenting symptoms, operative procedures, exact location and extent of the tumor as determined on the basis of radiologic and operative findings, postoperative outcome as well as clinical and radiologic follow-up findings. All patients underwent complete otologic and neurological examinations. All of the cases in our series underwent either high-resolution computed tomography (HRCT) with bone windows or gadolinium-enhanced magnetic resonance imaging (MRI Gd). Additionally, arteriovenous magnetic resonance angiography (16 cases) or four-vessel angiography (7 cases) was performed to study venous circulation and

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TABLE I. Classification of Schwannoma of Jugular Foramen According to Kaye et al. With Modifications by Pellet et al. and Samii et al.2,3 Class

A B C D

Primary intracranial tumor with a small extension into the bone Primary tumor in the jugular foramen with or without intracranial extension Primary extracranial tumor with extension into the jugular foramen or into the posterior fossa Dumbbell-shaped tumor with intracranial and extracranial extension

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TABLE II. Modified Sanna’s Classification for Reporting Hearing Results. Class

Pure-Tone Average (dB)

Standard Deviation Score (%)

0–20 21–30 31–40 41–60 61–80 ⱖ81

100–80 79–70 69–60 59–50 49–40 39–0

A B C D E F

auditory canal, 1 (4.5%). The 73-year-old woman managed by watchful expectancy had jugular foramen involvement with a limited extension into the cerebellopontine angle. After a 4-year follow-up period, this tumor did not show significant growth. One (4.5%) schwannoma (case no. 2) was exclusively extradural and 21 (95.4%) had both an intra- and extradural extension. Nineteen (86.3%) cases had typical dumbbell-shaped tumors involving the jugular foramen, cerebellopontine angle, and upper neck. The tumor size distribution is shown in Table V. At operation, the CN IX was identified as the nerve of origin in 6 cases and the CN X in 2 cases, whereas in the remainder, the origin of the tumor remained unknown. Three cases (case nos. 5, 8, and 19) had a cystic component in the cerebellopontine angle (Fig. 1). The jugular bulb was compressed and already closed by the tumor in 20 cases (90.9%). No patient had an ipsilateral dominant sinus or insufficient collateral venous drainage and none underwent preoperative embolization.

Treatment Eighteen patients underwent a primary operation and 4 patients presented with a recurrent tumor operated on elsewhere by the retrosigmoid approach (case nos. 2, 3, 16, and 19). All surgical procedures were performed by the senior author (M.S.). Early in our practice, we used IFTA-A in 3 patients and a transcochlear–transjugular approach with permanent posterior transposition of the facial nerve in 1 patient. Of the 3 patients who underwent IFTA-A, 2 (case nos. 2 and 3) had the cochlea drilled, having been eroded by the tumor; in 1 patient (case no. 1) with a preoperative dead ear, the IFTA-A was followed by second-stage surgery through a translabyrinthine approach; in another case (case no. 3) in which the tumor had an extradural portion greater than 4.0 cm, a planned second-stage procedure using the POTS approach was undertaken for removal of the intradural portion. From 1994 on, our team adopted the POTS as the main approach to treat these lesions. Of the 22 patients surgically treated, 12 (54.5%) underwent single-stage tumor removal through the POTS approach. In one patient (case no. 5) with a preoperative dead ear, a combined POTS–translabyrinthine approach was adopted. Two patients (case nos. 14 and 21) underwent a combined POTS–transotic approach because of massive erosion of the carotid canal (Fig. 2). Two patients in our series (case nos. 19 and 20) underwent a first-stage combined transcervical–subtotal petrosectomy because of a huge tumor component in the Laryngoscope 116: December 2006

neck; a translabyrinthine–transsigmoid–transjugular approach was used for the second-stage intradural removal of the tumor in one case (case no. 19) and the other one is waiting for the second-stage intradural removal of the tumor (Fig. 3). This staging strategy has been adopted to avoid the risk of having postoperative cerebrospinal fluid (CSF) leak resulting from the wide neck exposure and to reduce intracranial tension during the second stage. Total tumor removal was accomplished in 21 cases, except for the patient (case no. 20) waiting for the second stage. In one case (case no. 22), subtotal removal through a transcervical approach was planned to resect a 10-cm mass in the neck; a residual schwannoma was left in place at the jugular foramen area to avoid lower CN deficit. This patient was subsequently lost to follow up for a 9-year period. She returned to our center in April 2006 at which time a 3 ⫻ 3-cm mass was noted in the cerebellopontine angle. The tumor will be removed in the near future. So far, no patient has experienced recurrence during the follow-up period as ascertained by CT or MRI.

Surgical Technique for the Petrooccipital Transsigmoid Approach This approach is designed primarily for nonvascularized lesions of the jugular foramen with or without extension into the cerebellopontine angle and upper neck. The POTS is a posterolateral approach to the skull base and offers a direct and conservative route to the jugular foramen and adjacent areas while keeping the facial nerve in place and preserving the external auditory canal and middle ear. Areas that can be controlled by this approach include the jugular foramen, cerebellopontine angle, occipital condyle, the ipsilateral lower clivus, the vertical portion of the internal carotid artery lying below the eustachian tube, and the jugulocarotid space. The approach entails a retrolabyrinthine petrosectomy combined with a retrosigmoid craniotomy and occlusion of the sigmoid sinus and jugular vein. A limited neck approach is required to suture the jugular vein. Figure 4 displays a schematic presentation of the surgical steps for the POTS approach.12 A C-shaped postauricular skin incision is made. It begins approximately 3 cm above the auricle, curves 4 to 5 cm behind the postauricular sulcus, and slants inferiorly to end 2 cm below the tip of the mastoid. ● The skin flap is raised and is retracted anteriorly using elastic-banded skin hooks. ● An inferiorly based U-shaped musculoperiosteal flap is outlined. ● The sternocleidomastoid muscle is retracted posteriorly. The lateral process of the atlas is identified. Blunt dissection anterior to this point reveals the internal jugular vein. After liberating the vein, a suture is passed underneath it for later ligation. ● An extended mastoidectomy is performed. The sigmoid sinus is skeletonized. The digastric ridge is identified and the mastoid tip is amputated. ● A 4 ⫻ 4-cm retrosigmoid craniotomy is performed. ● The bone overlying the skeletonized sigmoid sinus and sinodural angle is removed. However, a piece of bone overlying the genu from the lateral to the Sanna et al.: Jugular Foramen Schwannoma

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TABLE III. Patient Demographics, Location of Tumor, Type of Operation, and Postoperative Complications in the 22 Patients Surgically Treated for Jugular Foramen Schwannoma.

Side

Preoperative Cranial Nerve Deficits

Tumor Class

F

L

V, IX

D

51 37

F F

R R

IX, X IX–XII

C D

4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

27 34 60 34 26 41 44 43 27 57 58 28 27 42 29 65

M F M F F M F M F M M M F M M M

R R L L R L L L R R L L R L L L

IX–XII — — XI IX–XII IX–XI IX–XII IX–XII — — IX, X, XII — IX–XI X IX IX–XII

D A D D D D D D D D D A D D D D

20

61

M

L

X–XII

D

21 22

52 67

M F

L R

IX–XII —

D D

Patient No.

Age (years)

Sex

1

40

2 3

Approach

IFTA-A (I stage) TL (II stage) IFTA-A* IFTA-A (I stage)* POTS (II stage) MTCA ⫹ transjugular POTS ⫹ TL POTS POTS POTS POTS POTS POTS POTS POTS POTS ⫹ TO POTS POTS POTS POTS Transcervical ⫹ subtotal petrosectomy (I stage) TL ⫹ transsigmoid–transjugular (II stage) Transcervical ⫹ subtotal petrosectomy (I stage)† POTS ⫹ TO Transcervical†

New Cranial Nerve Deficits

X XI — — IX IX IX, X — — — — IX, X IX, X XI IX–XII XII IX, XI — —

— — —

*Drilling of the cochlea because filled by tumor. †Waiting for the second (intradural) stage. IFTA-A ⫽ infratemporal fossa approach–type A; TL ⫽ translabyrinthine; POTS ⫽ petrooccipital transsigmoid approach; MTCA ⫽ modified transcochlear approach; TO ⫽ transotic approach.

● ●

●

● ●

sigmoid sinus is left in place to allow extraluminal compression with Surgicel. The dura is separated from the underlying bone using a septal dissector. The retrofacial cells are then drilled. The mastoid segment of the facial nerve is identified. The posterior semicircular canal is better identified but not blue-lined with care being taken not to injure its ampulla while drilling the retrofacial cells superiorly. With gentle pressure on the sigmoid sinus and the posterior fossa dura using the suction irrigator, the endolymphatic sac and the duct are identified and sectioned to allow further detachment of the dura from the labyrinth. Next the infralabyrinthine cells are drilled taking care not to injure the cochlea lying superolaterally. The proximal part of the sigmoid sinus is compressed extraluminally with a piece of Surgicel placed between the sinus and the overlying bone at

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its junction with the lateral sinus. The internal jugular vein in the neck is ligated. Next the sigmoid sinus is closed proximally and distally with 2 tungsten clips and opened with a beaver knife. The posterior fossa dura is opened with a horizontal incision starting approximately 3 cm posterior to the sigmoid sinus, coursing anteriorly, traversing the medial wall of the sinus, and ending at the level of the posterior semicircular canal. Bipolar coagulation of the dura is performed before its aperture to decrease bleeding. ● The dura is held by 2 stay sutures, 1 for the superior dural flap and the other for the inferior one. The sutures are fixed to the skin. Tumor removal proceeds accordingly. ● Patients with a highly pneumatized temporal bone have a higher possibility of developing postoperative CSF rhinorrhea. All opened perilabyrinthine and retrofacial air cells should be sealed with bone wax. Sanna et al.: Jugular Foramen Schwannoma

TABLE IV. Presenting Features (23 patients). Symptoms and Signs

No. of Patients (%)

Dysphonia Dysphagia Hearing loss Shoulder weakness Tinnitus Spontaneous nystagmus Instability Gait disturbance Glossal atrophy Pulsatile tinnitus Headache Middle ear mass Facial weakness Vertigo Neck mass

11 (47.8) 10 (43.7) 7 (30.4) 5 (21.7) 5 (21.7) 4 (17.3) 4 (17.3) 4 (17.3) 3 (13) 2 (8.6) 2 (8.6) 2 (8.6) 1 (4.3) 1 (4.3) 1 (4.3)

● At the end of the procedure, the retrosigmoid dura is approximated with interrupted Vicryl 4 – 0 sutures. A small defect at the level of the jugular fossa remains. The defect as well as the operative cavity is plugged with abdominal fat.

TABLE V. Tumor Size (cm). Patient

Tumor Class

Intracranial Extension

Extracranial Extension (beyond jugular foramen)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

D C D D A D D D D D D D D D A D D D D D D D

4.5 0.0 2.5 4.0 3.5 2.0 2.5 4.0 2.9 2.5 1.5 1.0 2.4 5.0 3.0 3.7 1.5 2.5 5.5 4.0 3.0 3.0

3.0 2.5 4.2 2.0 0.0 1.0 0.5 4.0 1.0 2.5 1.9 1.5 2.0 4.0 0.0 1.0 1.5 2.5 11.3 6.0 2.0 10.0

Tumor size in centimeters was measured as the largest intracranial and extracranial diameters on magnetic resonance imaging or computed tomography scan.

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● The musculoperiosteal flap is sutured back with inverted Vicryl 1-0 sutures. ● The skin is closed with 3-0 silk and a tight dressing is applied. No drains are inserted. The POTS approach can be combined with different other approaches, e.g., the translabyrinthine approach in cases with preoperative ipsilateral sensorineural hearing loss and the transotic approach in cases in which the tumor shows massive involvement of the middle ear and internal carotid artery (Fig. 5).

Lower Cranial Nerve Status Sixteen (72.7%) of the patients were found to be have at least one CN deficit in the preoperative evaluation. The most common CNs involved were the IX (13 cases) and X (13 cases) followed by the XI (11 cases) and the XII (9 cases). Seven (31.8%) patients had paralysis of all 4 CNs on initial diagnosis. Six (27.2%) patients showed no lower CN palsy. Immediately after surgery, none of the patients recovered function of the preoperatively paralyzed lower CNs. A new deficit of 1 or more of the lower CNs was recorded in 11 (50%) patients. These included paralysis of CNs IX and X in 3 cases. Cranial nerve X alone was lost in one case. New isolated deficit of CN IX occurred in 2 cases. Two cases experienced isolated paralysis of CN XI and its loss was associated with the IX in another case. Isolated loss of the CN XII occurred in one patient. One other patient had the loss of all 4 CNs. Among the 6 patients who showed no preoperative CN palsy, 2 patients experienced an isolated loss of CN IX, 2 had both CN IX and X deficit, and the remaining 1 had loss of all 4 CNs. A prophylactic nasogastric feeding tube was needed in the immediate postoperative period for those patients who developed deficits of CNs IX and X. Oral intake was started on the third postoperative day in patients with preoperative paralysis and on the sixth postoperative day in the acute paralysis cases. On long-term follow up, all patients were able to compensate well for their lower CN deficits by the help of speech and swallowing rehabilitation. In no cases was vocal fold injection needed. Physical therapy was administered in patients with CN XI paralysis to prevent persistent shoulder dysfunction and pain.

Facial Nerve Status Preoperatively, 19 (86.3%) of the 22 surgically treated patients had grade I facial nerve function and 3 patients (13.6%) had grade II paresis (case nos. 2, 5, and 19). Two patients with grade II had been previously operated on in other centers. The 3 patients who were operated on by IFTA-A underwent permanent anterior transposition of the facial nerve. In the immediate postoperative period, 1 had grade IV (case no. 1) and 2 had grade VI (case nos. 2 and 3). At 1-year follow up, 2 of these patients (case nos. 1 and 3) had grade I and 1 reached grade IV (case no. 2). The patient (case no. 4) who underwent posterior transposition of the facial nerve had grade VI immediately after surgery and reached grade III at 1-year follow up. Sanna et al.: Jugular Foramen Schwannoma

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Fig. 1. Magnetic resonance imaging (MRI) with gadolinium showing a right jugular foramen schwannoma measuring 4 cm in the cerebellopontine angle with a 4-cm extension through the jugular foramen into the upper neck (case no. 8). (A) Axial MRI at the level of the jugular foramen. Notice the huge cystic component in the cerebellopontine angle. (B) Sagittal MRI showing the tumor extending from the cerebellopontine angle to the neck. (C) Coronal MRI showing the tumor in the right cerebellopontine angle causing marked displacement of the brainstem. Notice tumor extension into the jugular foramen. (D) Axial MRI showing the tumor extension into the neck. The internal carotid artery is anteriorly displaced by the tumor with an intervening good plane of cleavage.

Among the cases who underwent the POTS approach, 10 (83.3%) had grade I immediately after surgery and 2 (case nos. 8 and 10) had grade III, both of which recovered to grade I at 1-year follow up. One of the 2 patients (case no. 19) who underwent a combined transcervical–subtotal petrosectomy approach still has grade VI facial nerve paralysis at 3 months follow up. Table VI summarizes the facial nerve results.

Hearing Status Nonhearing preservation tumor removal was performed in 5 cases. Four patients had a preoperative dead ear (case nos. 1, 4, 5, and 19) and 1 patient had poor preoperative hearing (case no. 14). Two of the 3 patients (case nos. 2 and 3) treated via IFTA-A had good preoperative hearing. These patients experienced postoperative deafness resulting from the necessity of dril-

Fig. 2. (A) Axial magnetic resonance image with gadolinium showing a left jugular foramen schwannoma extending to the petrous apex with involvement of the horizontal portion of the internal carotid artery (case no. 21). (B) Computed tomography scan of the same case showing the bony erosion at the level of the petrous apex.

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Fig. 3. (A) Computed tomography scan, coronal view, of a recurrent jugular foramen schwannoma showing a huge extension in the neck (case no. 19). (B) T2-weighted magnetic resonance image (MRI) (axial view) of the same tumor showing the intracranial extension. (C) Postoperative T1-weighted MRI with gadolinium (coronal view) after the firststage surgical removal showing the tumor remnant at the jugular foramen and intracranial compartment. (D) Postoperative T2-weighted MRI showing total intradural tumor removal.

ling of the cochlea, which was found eroded by the tumor. Hearing preservation was attempted in 12 cases (54.5%) through the POTS approach. According to the modified Sanna classification, the preoperative hearing levels were as follows: class A, 10 cases (83.3%), and class B, 2 cases (67.7%). Postoperatively, 1 patient (case no. 9)

had developed total deafness attributable to unforeseen coagulation of the labyrinthine artery in a tumor with a large intradural component. In another case (case no. 15), a 60-dB conductive hearing loss resulted from the middle ear and mastoid obliteration performed during revision surgery because the patient experienced postoperative CSF leak. Hearing was preserved in 10 patients (83.3%),

Fig. 4. Schematic presentation of the petrooccipital transsigmoid approach. (A) Skin incision. (B) An inferiorly based U-shaped myoaponeurotic flap is raised. The flap extends from 1 to 2 cm above the zygomatic arch superiorly to the level of the mastoid tip inferiorly. Anteriorly, a strip of periosteum is left a few millimeters posterior to the external auditory meatus to allow resuturing of the flap during closure. The flap is mobilized down to the level of the atlas. (C) Extradural part of the approach is completed. The myoaponeurotic flap (MF) is turned caudally. The bone removal includes a suboccipital craniotomy and a posterolateral petrosectomy up to the posterior labyrinth, the antrum, and the fallopian canal (FC). The sigmoid sinus (SS) runs across the field. The dotted line shows the dura incision. The jugular vein (JV) is ligated in the upper neck. (D) The posterior cranial fossa is exposed. The dura flaps are retracted and held by 2 stay sutures, 1 for the superior dural flap and the other for the inferior one. The sutured are fixed to the skin. ICA, internal carotid artery; JV, jugular vein.

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Fig. 5. Possible combinations of the petrooccipital transsigmoid (POTS) approach. (A) A combined POTS and translabyrinthine approach. (B) A combined POTS and transotic approach.

and of these, 7 patients maintained their preoperative hearing level (class A). The remaining 3 patients experienced an air-conduction threshold deterioration ranging from 20 to 40 dB and a bone-conduction threshold deterioration ranging from 15 to 25 dB. One of these patients experienced a postoperative class C and the other 2 had class D. The preoperative and the most recent postoperative hearing results for all cases are displayed in Table VII.

Complications There were no peri- or postoperative deaths in this series. One (4.5%) patient experienced postoperative CSF rhinorrhea. This patient (case no. 6) required surgical

TABLE VI. Preoperative, Immediate Postoperative, and Final Facial Nerve Function According to the House-Brackmann Scale. Patient No.

Preoperative

Immediately Postoperative

Follow Up

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

I II I I II I I I I I I I I I I I I I II I I I

IV VI VI VI I I I III I III I I I I I I I I VI I I I

I IV I III I I I I I I I I I I I I I I VI I I I

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management by obliteration of the middle ear space and eustachian tube with abdominal fat and blind sac closure of the external auditory canal. The same patient developed bacterial meningitis. Two patients (9%) had a subcutaneous CSF collection. One (case no. 9) of these 2 patients required management in the form of lumbar drain placement, which stopped the CSF collection in 3 days. The other case (case no. 7) was managed conservatively with aspiration and a tight dressing. One patient needed a temporary postoperative tracheostomy because of bilateral vocal cord paralysis of unknown etiology (case no. 16) and respiratory difficulty. The contralateral vocal cord paralysis spontaneously resolved in 3 weeks. There were no problems related to the venous drainage changes resulting from closure of the sigmoid sinus and jugular vein.

DISCUSSION Intradural lower CN schwannomas can safely be accessed by the retrosigmoid approach, whereas tumors confined to the neck can be managed by transcervical approaches. Lower CN schwannomas contained within the jugular foramen with both intradural and extracranial components represent a surgical challenge, and controversy continues to exist on the choice of surgical approach and whether or not the operation should be staged. The major problems include: 1) adequate exposure because these tumors spread in 3 different compartments (intradural, intrapetrous, and extracranial); 2) the vertical portion of the facial nerve is centered on and closely related to the jugular bulb; and 3) potential injury to the lower cranial nerves. In addition, most of these tumors have preoperative normal hearing and therefore, hearing preservation, if possible, has to be sought. JFSs can present with a variability of presenting symptoms depending on the size and anatomic location of the tumor. Progressive lower CN deficits represent the most frequent presenting complaints. In this series, the most common CN deficits included the IX (59%) and X (59%) followed by the XI (50%) and the XII (41%). The second common clinical picture mimics the presentation of a cerebellopontine angle lesion with ipsilateral sensorineural hearing loss, tinnitus, and vertigo, thus indistinguishable from a vestibular schwannoma. Preoperative facial nerve palsy is rare. In the present series, hearing Sanna et al.: Jugular Foramen Schwannoma

TABLE VII. Pre- and Postoperative Pure-Tone Averages for Air and Bone Conduction and Corresponding Hearing Class According to Modified Sanna Classification. Patient No.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

20

21 22

Approach

Preoperative PTA BC (dB)

Preoperative PTA AC (dB)

Preoperative Class

Postoperative PTA BC (dB)

Postoperative PTA AC (dB)

Postoperative Class

DE 15 10 DE DE 20 15 10 10 10 10 10 15 50 20 20 10 10 DE

DE 30 60 DE DE 25 20 10 10 10 10 10 20 70 20 30 10 10 DE

DE B D DE DE B A A A A A A A E A B A A DE

DE DE DE DE DE 40 15 10 DE 10 10 20 15 DE 35 45 10 10 DE

DE DE DE DE DE 45 20 10 DE 10 10 40 20 DE 60 55 10 10 DE

DE DE DE DE DE C A A DE A A C A DE D D A A DE

10

10

A

10

60

D

40 10

40 10

C A

DE 10

DE 10

DE A

IFTA-A/TL IFTA-A* IFTA-A/POTS* MTCA ⫹ transjugular POTS ⫹ TL POTS POTS POTS POTS POTS POTS POTS POTS POTS ⫹ TO POTS POTS POTS POTS Transcervical ⫹ subtotal petrosectomy/TL ⫹ transsigmoid– transjugular Transcervical ⫹ subtotal petrosectomy POTS ⫹ TO Transcervical

*Drilling of the cochlea because filled by tumor. PTA ⫽ pure-tone average; AC ⫽ air conduction; BC ⫽ bone conduction; ABG ⫽ air– bone gap; DE ⫽ dead ear; IFTA-A ⫽ infratemporal fossa approach–type A; TL ⫽ translabyrinthine; POTS ⫽ petrooccipital transsigmoid approach; MTCA ⫽ modified transcochlear approach; TO ⫽ transotic approach.

loss was the presenting symptom in 30.4% of cases at the time of initial diagnosis. Other otologic symptoms included tinnitus (21.7%) and vertigo (4.3%). In other series, hearing loss represented the initial symptom in 28.5% to 75% of patients and lower CN dysfunction was present in 50% to 80%.2–3,5,8 Less frequently, these tumors resemble paragangliomas with pulsatile tinnitus and a hypotympanic mass on otoscopy. The most important radiologic differential diagnosis of these tumors includes jugular paragangliomas, vestibular schwannomas, and meningiomas. HRCT with bone windows and MRI with gadolinium are essential and complementary investigations to accurately delineate the extent of the tumor preoperatively and optimize its management. JFSs appear isodense or slightly hyperdense on CT scans and usually cause enlargement of the jugular foramen with smooth well-defined bony margins and no signs of bony infiltration. In contrast, paragangliomas and meningiomas cause irregular erosion of the margin of the jugular foramen and infiltrate surrounding bone.10 Unlike jugular paragangliomas, bone destruction of the jugular fossa is much less evident in meningiomas. The carotLaryngoscope 116: December 2006

icojugular spine is characteristically eroded in paragangliomas, whereas mild hyperostosis may be present in meningiomas. Schwannomas can extend into the cerebellopontine angle superiorly or into the parapharyngeal space inferiorly. Large lesions can extend to involve the vertical carotid canal and the petrous apex. Schwannomas are usually iso- or hypointense on T1-weighted images and iso- or hyperintense on T2-weighted images and enhance with gadolinium. JFSs situated mainly in the cerebellopontine angle can be differentiated from vestibular schwannomas by their more caudal location, and they do not cause widening of the internal auditory canal (Fig. 6). On MRI, paraganglioma appears hypointense on T1-weighted images, whereas on T2-weighted images, the tumor component is isointense. After gadolinium administration, paragangliomas show dishomogeneous enhancement with a “salt and pepper” appearance and multiple flow-void areas. On MRI, meningiomas are isoor hypointense on T1 and hyperintense on T2 images. Meningiomas can be distinguished from schwannomas by the presence of irregular borders, enhancing more Sanna et al.: Jugular Foramen Schwannoma

2199

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Sanna et al.: Jugular Foramen Schwannoma

Leonetti et al.6 (2001)

13

6

16⫹2†

Çokkeser et al.8 (2000)

Lee et al.4 (2001)

19

Mazzoni et al.3 (1997)

14

16

1

Samii et al.2 (1995)

Tan et al. (1990)

Study

No. of Cases

—

1 (16.6)

3 (16.6)

5 (26.3)

8 (50)

10 (71.4)

A

—

1 (16.6)

7 (38.8)

7 (36.8)

2 (12.5)

—

B

10 (76.9)

2 (33.3)

1 (5.5)

2 (10.5)

1 (6.2)

1 (7.1)

C

Tumor Type*

3 (23.1)

2 (33.3)

7 (38.8)

5 (26.3)

5 (31.2)

3 (21.4)

D

POTS IFA IFA/translabyrinthine IFA/transcochlear retrosigmoid preauricular infratemporal fossa 2 transcervical 1 transparotid 3 transcondylar/retrosigmoid

1 2 1 1 1 7

9 posterior fossa 3 posterior fossa/neck dissection 1 supratentorial and infratentorial 3 transcondylar/retrosigmoid 8 suboccipital 8 cervical/transmastoid 10 POTS 4 POTS/translabyrinthine 1 POTS/cervical 2 IFTA-A 1 transcochlear 1 IFA/translabyrinthine 1 radical jugulopetrosectomy 5 IFA 5 infralabyrinthine 3 translabyrinthine/suboccipital 3 retrolabyrinthine/suboccipital 2 retrolabyrinthine/extended facial recess

Surgical Approach

10 total (76.9) 2 near total (15.3) 1 subtotal (15.3)

4 total (83.3) 1 near total (16.6) 1 subtotal (16.6)

16 total (100) 2 recurrences (12.5)

19 total (100)

16 total (100)

10 total (100) 3-Recurrences (21.4)

Tumor Resection

3 (23)

3 (50)

3 (16.6)

4 (21)

3 (18.7)

—

Postoperative FN paresis

TABLE VIII. Comparative Review of the Major Jugular Foramen Schwannomas Series in the Last 15 Years.

mastoiditis CSF leak (6.2) 2-stage procedure temporary tracheostomy HB grade II and 2 HB grade III

(Continues)

3 CSF leaks (18.7) 4 vocal cord injection, 3 laryngoplasty 1 gastrostomy 1 death as a result of complicated CSF leak followed by meningitis 2 HB grade II and 1 HB grade III 2 thyroplasty 1 meningetis 1 embolic infarct (middle cerebral artery embolism) 3 transient facial nerve palsy 2 feeding gastrostomy tube 1 tracheotomy 4 vocal cord medialization, 1 Gelfoam vocal fold injection 1 cervical hematoma 3 transient facial nerve palsy

2 1 1 1 2

—

Comments

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2201

6

6

23‡

Kadri et al.7 (2004)

Wilson et al.5 (2005)

Present series

2 (8.6)

1 (16.6)

—

3 (33.3)

A

—

—

—

2 (22.2)

B

1 (4.3)

2 (33.3)

—

2 (22.2)

C

Tumor Type*

20 (86.9)

3 (50)

6 (100)

2 (22.2)

D

retrosigmoid retrosigmoid/transjugular far lateral retrosigmoid/far lateral subtemporal/infratemporal

2 IFA 1 IFA without FN transposition 1 transcondylar 1 translabyrinthine 1 far lateral 1 IFA 1 FA/translabyrinthine 1 FA/POTS 1 MTCA 12 POTS 2 POTS/transotic 1 POTS/translabyrinthine 1 transcervical– subtotal petrosectomy/TL– transsigmoid–transjugular 1 transcervical– subtotal petrosectomy 1 transcervical

6 transcondylar/suprajugular

3 2 2 1 1

Surgical Approach

21 total (95.5)§ 1 subtotal (4.5)

6 total (100)

6 total (100)

8 total (88.9) 1 subtotal (11.1) 1 recurrence (11.1)

Tumor Resection

3 (13.6)

3 (50)

1 (16.6)

2 (22)

Postoperative FN paresis

Comments

CSF leak (22.2) bacterial meningitis thyroplasty temporary percutaneous endoscopic jejunostomy hemiparesis aspiration pneumonia ⫹ tracheotomy and medialization vocal cord with Teflon transient FN palsy vertebral artery injury without postoperative sequela transient FN palsy and 1 case with HB grade III 4 2-stage procedures 1 patient is waiting for second stage 1 CSF leak (4.5) 1 meningitis 1 tracheostomy 1 HB grade III, 1 grade HB IV, and 1 HB grade VI

2

1 2

1 1

2 1 3 2

Numbers in parentheses denote percentage. *Classification of schwannoma of jugular foramen according to Kaye et al. with modifications by Pellet et al. and Samii et al.2,3 †Two recurrences appeared 7 and 8 years after primary operations. ‡One patient is managed with watchful expectancy. §One patient is waiting for the second (intradural) stage. FN ⫽ facial nerve; HB ⫽ House-Brackmann; POTS ⫽ petrooccipital transsigmoid approach; CSF ⫽ cerebrospinal fluid; IFA ⫽ type A infratemporal fossa approach; MTCA ⫽ modified transcochlear approach.

9

Sarma et al.9 (2002)

Study

No. of Cases

TABLE VIII. (Continued)

Fig. 6. (A) Magnetic resonance image (MRI) with gadolinium showing a left cerebellopontine angle mass centered on the internal auditory canal, which is not involved (case no. 9). The tumor can be mistaken for a medially placed vestibular schwannoma. (B) MRI of the same tumor (more cranial section) showing the intradural extension with invasion of the jugular foramen.

intensely with gadolinium and, most often, a lower intensity on T2. The serpentine flow voids characteristic of paraganglioma are absent in meningioma. In addition, the frequently encountered “dura tail” sign after gadolinium administration is pathognomonic of meningioma. Although schwannomas tend to compress the jugular bulb, paragangliomas and meningiomas tend to invade the vessel with intraluminal growth. Careful preoperative evaluation of the venous flow (by means of arteriovenous MR angiography or four-vessel angiography) of the sigmoid sinuses, jugular bulbs, and jugular veins is of paramount importance in avoiding complications (i.e., benign intracranial hypertension and venous cerebral infarct) related to closure of the dominant venous drainage of the brain. Total tumor removal is the treatment of choice for JFSs. No general consensus has been reached on the choice of surgical approach or whether or not the operation should be staged. Table VIII lists the approaches and outcomes in the main recently published series, including the present one. The ideal surgical approach should adhere to the basic tenets of obtaining a wide access to the whole tumor with minimal brain manipulation while minimizing morbidity related to additional CN deficits. Additional goals of surgery include preservation of the inner ear, middle ear, and facial nerve function. Single-stage total tumor removal should be attempted when possible. In approaching tumors located mainly in the cerebellopontine angle, the suboccipital approach extended to the jugular fossa2 and the translabyrinthine5 approach have been proposed. Tumors mainly confined in the skull base and neck have been approached by the cervical transmastoid,2 IFTA-A,11 transcondylar, far lateral,5 preauricular infratemporal, and transcervical6 approaches. For dumbbellshaped tumors, the main advocated approaches are the suboccipital approach combined with an IFTA-A,2 combined extradural–posterior–petrous and suboccipital approach,13 transcondylar suprajugular7 and infratemporal– translabyrinthine5 approaches. An uncorrected presurgical planning gives rise to a high rate of recidivism as confirmed by our 4 previously treated patients by retrosigmoid approach. In fact, the retrosigmoid approach does not provide access to the jugular foramen and neck. Franklin et al.14 advocated the IFTA-A for all cases. The same attitude was followed by us at the beginning of our experience. Despite the excellent exposure of the jugular foramen area, the IFTA-A has the disadvantages of a Laryngoscope 116: December 2006

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postoperative conductive hearing loss resulting from ear canal closure and facial nerve paresis related to the anterior rerouting of the facial nerve. Accordingly with Samii et al.,2 we believe that if the intradural tumor extension is more than 2 cm, this approach does not offer full view of the brainstem and cerebellum and should be combined with a retrosigmoid approach. The fallopian bridge technique,15 the POTS approach,12 and the combined extradural–posterior petrous and suboccipital approach13 avoid facial nerve transposition and ear canal closure. In 1997, Mazzoni et al.3 reported a series of 19 patients who underwent one-stage total tumor removal in which 15 of the patients (79%) were operated on by the POTS approach without facial nerve transposition. According to Mazzoni et al.,3,12 anterior transposition of the facial nerve, which is crucial in controlling infiltrative and vascular lesions of jugular foramen (i.e., paragangliomas), is not needed to accomplish safe and total removal of JFSs. Eighty-seven percent of their patients obtained grade I facial nerve function and 13% had grade II. The same surgical attitude has been subsequently adopted by C ¸ okkeser et al.8 in 2000. The authors reported their experience with 16 cases of JFSs removed in one stage. In 72% of their patients, tumor removal was accomplished without facial nerve transposition achieving normal postoperative facial nerve results (HB grade I) in 92.3% of their cases. Unfortunately, the authors did not reported hearing results. However, our technique differs from that reported by C ¸ okkeser at al.,8 especially for a smaller approach to the neck without section of the sternocleidomastoid muscle. Usually, small neck exposure is sufficient for removal of the extracranial portion of the tumor and further reduces the risk of a CSF leak from the neck incision. Although neck exposure by the POTS approach is limited compared with the IFTA-A or the cervical approach, it is adequate for the relatively safe excision of such noninvasive tumors. In fact, paragangliomas usually infiltrate the carotid canal and may invade the adventitia of the internal carotid artery. For this reason, the surgical approach needs to control the whole length of the artery to be able to perform a subadventitial dissection of the invaded artery. On the contrary, schwannomas erode but do not infiltrate the petrous bone. Unlike paragangliomas, schwannomas do not tend to infiltrate the internal carotid artery walls. In this series, we used the POTS approach in most cases for single-stage tumor removal. At the beginning of Sanna et al.: Jugular Foramen Schwannoma

In accordance with others, our results confirm the difficulties in preserving lower CN function despite the surgical technique used.1,3– 6 This must be taken into consideration during the preoperative planning. Sudden palsy of previously functioning lower CNs in elderly patients would be met with serious morbidity. Watchful expectancy is therefore adopted, and surgery is only indicated in case of CN deficits and/or impending neurologic complications. Lower CN deficits seem to be inherent to the disease rather than the surgical approach used.3,8 In this series, lower CN deficits took place either as a result of the intentional sacrifice or functional loss despite anatomic integrity. Our results apparently compare unfavorably with the other major series reported in the literature (Table IX). However, they can be justified by the size of the lesions and the higher rate of dumbbell-shaped tumors, which is 86.9%. Although no recovery of lower CN deficits may be expected, on long-term follow up, all patients well compensated for their lower CN loss by the help of speech and swallowing rehabilitation. Physical therapy was administered in patients with CN XI paralysis to prevent persistent shoulder dysfunction and pain. Postoperative CSF leaks represent another serious complication. In our series, one patient (4.5%) experienced CSF rhinorrhea that required surgical management. Two patients (9%) experienced subcutaneous CSF collection. One of these patients was managed conservatively with lumbar drain placement. CSF leaks have been attributed to the single-stage removal of tumors with both intradural and extracranial extension, and some authors have proposed a two-stage procedure for such cases.14 After our earlier cases, we chose a single-stage procedure for all cases irrespective of their intradural size. We reserved a two-stage procedure only for those rare cases of transdural tumors massively extending into the neck (case nos. 19 and 20). This staging strategy helps to reduce the intracranial tumor massrelated tension and avoids the high risk of having a postoperative CSF leak. The reason for such a risk is the need for wide neck exposure, and hence the subarachnoid space becomes widely connected to the open neck spaces. CSF leak through the neck is particularly difficult to manage as a result of the impossibility of applying any sort of compression. Preventing steps to minimize the risk of a

our experience, we used the IFTA-A, because we were not fully aware of the rationale of the POTS approach. Our strategy for surgical removal was changed over the years from IFTA-A to the POTS approach. Preservation of hearing and facial nerve functions appeared to be the specific advantages of the POTS approach. Keeping the facial nerve, the external auditory canal, and the middle ear in place did not hamper the necessary exposure for tumor removal in these nonvascularized and noninfiltrative tumors. Sigmoid sinus transection gave optimal visualization of the cerebellopontine angle, whereas opening the jugular bulb provided adequate control of the jugular foramen. The jugular bulb is normally already closed by progressive tumor compression, so collateral venous drainage ascertained by preoperative arteriovenous MR angiography is usually well developed. In our cases, the jugular bulb had already collapsed because of the tumor in 20 of 22 surgically treated cases. If preoperative hearing is unserviceable, the POTS approach can be combined with the translabyrinthine approach. If a massive erosion of the carotid canal is present, the POTS approach is combined with a transotic approach. Finally, a combined transcervical–subtotal petrosectomy was performed in 2 cases with a huge tumor component in the neck. One of these 2 cases has already completed the second-stage intradural tumor removal by using a translabyrinthine–transsigmoid–transjugular approach and the second one is still waiting for the second-stage surgery. Preservation of hearing function is a poorly recorded entity among the studies. Mazzoni et al.10 reported that 11 (73.3%) of their patients operated on by the POTS approach maintained hearing at the preoperative level and in other 4 (26.7%) patients with unserviceable preoperative hearing, the approach included the labyrinth. Recently, Wilson et al.5 reported that 5 of their 6 patients with JFS underwent nondestructive surgery and 4 of them maintained good hearing postoperatively. In the present series, 54.5% of patients had normal preoperative hearing (Sanna class A), and another 13.6% had only mild to moderate hearing loss (Sanna class B). Twelve patients had hearing-preserving surgery representing 54.5% of our series. Good hearing was preserved in 10 cases (83.3%) operated on by the POTS approach and 58.3% of the patients maintained their preoperative hearing level.

TABLE IX. Preoperative, Postoperative, and New Lower Cranial Nerve Deficits. Lower Cranial Nerve Deficits (preoperative/postoperative) Study

No. of Cases

IX

X

XI

XII

16 19 6 13 9 6 6 22

8/8 9/13 (4) 4/5 (1) 1/1 2/2 5/5 0/2 (2) 13/20 (7)

12/13 (1) 8/14 (6) 4/5 (1) 8/13 (5) 2/2 6/6 2/2 13/18 (5)

6/6 6/8 (2) 3/3 2/3 (1) 1/1 4/4 0/1 (1) 11/15 (4)

5/6 (1) 6/6 2/2 3/8 (5) 0/0 4/4 3/3 9/11 (2)

Samii et al.2 (1995) Mazzoni et al.3 (1997) Lee et al.4 (2001) Leonetti et al.6 (2001) Sarma et al.9 (2002) Kadri et al.7 (2004) Wilson et al.5 (2005) Present series

Numbers in parentheses denote new deficits.

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CSF leak when performing the POTS approach are the following: 1) the occipital dura and the medial wall of the sigmoid sinus are sutured; 2) all opened infralabyrinthine air cells should be sealed with bone wax; 3) the operative cavity is obliterated with long strips of abdominal fat as we usually do in vestibular schwannoma surgery. The fat should protrude intradurally at the level of the presigmoid intradural opening to fill the defect left by tumor removal; 4) a limited bone removal at the level of the jugular foramen area; and 5) this together with the specially designed myoaponeurotic flap delimit the confines of the resultant surgical cavity and help proper containment of the fat. We advocate total rather than partial removal. Although total extirpation may entail losing the nerves involved in the majority of cases, most patients tolerate this paralysis well. Preoperative paresis of the nerves subsequently sacrificed, the relatively young age of these patients, and the integrity of the contralateral nerves are all important factors in this respect. Incomplete removal, on the other hand, involves high risk of recurrence. The incidence of recurrences has been reported to be between 0% and 33.3%.1,3,5–9

CONCLUSIONS Total tumor removal is the first option in cases of jugular foramen schwannomas. Radiologic observation or partial removal is advisable in elderly and/or debilitated patients with preoperative normal CN function. Preservation of the lower CN function is achieved in rare cases when the jugular foramen area is involved by the tumor. The risk of a new deficit of one or more of the lower CNs must be taken into account when planning surgical tumor removal. The POTS approach represents our preferred surgical option. It has the advantage of excellent control of the jugular foramen, permitting total removal of an intradural and extradural tumor in a single stage with preservation of the middle and inner ear as well as facial nerve function.

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