Infratemporal approaches to nasopharyngeal tumors

Eur Arch Otorhinolaryngol (1997) 254 (Suppl. 1):S165-S168 HEAD

9 Springer-Verlag 1997

AND NECK

C. S u f i r e z 9 L . A . G a r c i a 9 R . F e r n f i n d e z J. P. R o d r i g o 9 B . R u i z

de Le6n

Infratemporal approaches to nasopharyngeal tumors

Twenty patients with neoplasms originating in the nasopharynx were operated using the infratemporal fossa approach with facial translocation (15 cases), the subtemporal-preauricular infratemporal approach (2 cases), and the transmandibular approach (3 cases). A craniect o m y was also required in 14 cases. Fifteen tumors were malignant, while 5 were juvenile angiofibromas with infratemporal and intracranial extensions. Most of the lesions were large and involved multiple areas of the skull base. T u m o r excision was total in all but 3 patients. Local flaps were utilized in all patients to seal the operative cavity and consisted of temporalis muscle flaps. The most frequent postoperative complications were w o u n d infections and cerebrospinal leaks. Two patients died as a result of postoperative complications. To date, 1 patient has died from disease and 3 are alive with local or distant disease. Abstract

K e y w o r d s Infratemporal fossa 9 Skull base Nasopharyngeal tumors 9 Subtemporal surgical approach

Introduction In addition to undifferentiated carcinomas, the nasopharynx is the site of a wide variety of u n c o m m o n benign and malignant tumors. Some of these tumors can be treated primarily with radiotherapy, but in other types only surgery is effective. On the other hand, local recurrences after radiotherapy make salvage surgery occasionally necessary. Most of the malignant tumors share a pattern of spread that is similar, with the exception of adenoid cystic carcinomas which demonstrate perineural invasion. Usually, when the diagnosis of tumor is made, it is no longer confined to a primary site within the nasopharynx, but involves more than one site or has spread to adjacent structures. If this is the case, the sites more c o m m o n l y involved are the infratemporal fossa, posterior part of the C. Sufirez (N~) - L. A. Garcfa 9R. Fernfindez de Le6n 9 J. P. Rodrigo 9 B. Ruiz Department of Otolaryngology, Hospital Central de Asturias, Celestino Villaamil, s/n, E-33006 Oviedo, Spain

nasal cavity, prevertebral muscles, clivus and intrapetrous internal carotid artery. Intracranial spread occurs when the tumor enters the intracranial compartments through the sphenoid sinus, eroding the greater sphenoid wing in the floor of the middle cranial fossa, or passes through different foramina in the base of the skull, with secondary involvement of the cavernous sinus and trigeminal ganglion. The juvenile angiofibroma is the most frequent benign tumor of the nasopharynx. A number of these tumors spread widely into the infratemporal fossa, with intracranial progression through the superior orbital fissurae. A number of approaches to neoplasms within the infratemporal fossa and the nasopharynx have been reported. These include the subtemporal-preauricular infratemporal fossa approach [10], the subtemporal approach with facial translocation [6], various infratemporal approaches of type C [1, 2], maxillary swings [4], and the transmandibular approach [7, 9]. The purpose of this paper is to present our experience with different infratemporal fossa approaches and criteria for the selection of patients.

Patients and methods Twenty patients with tumors involving the nasopharynx and treated by an infratemporal approach were studied. All patients were managed at the Department of Otolaryngology, Hospital Central de Asturias, between 1 January 1992 and 31 December 1995. Operations performed on nasopharyngeal tumors through an approach other than the infratemporal were not included in this study. Seventeen patients were men and 3 women. The age range was 8-70 years with a mean of 44 years. Fifteen tumors were malignant: squamous cell carcinomas (4), recurrent undifferentiated carcinomas (4), adenoid cystic carcinomas (3), adenocarcinomas (3), and malignant pleomorphic adenoma (1). The remaining 5 patients had a juvenile angiofibroma with infratemporal and intracranial involvement. UICC criteria for TNM staging were used. Of the 15 malignant tumors, 2 were T2, 4 T3 and 9 T4. Most of the malignant and benign tumors were large and involved multiple areas of the skull base, including the posterior part of the nasal cavity (16), infratemporal fossa (15), cavernous sinus or parasellar region (7), internal carotid artery (5), dura (5), clivus (3), and petrous apex (2). Examples are shown in Figs. 1-5. Seven patients had been treated previously, either with surgery (1 case) or with radiotherapy (6 cases).

S 166 Fig. 1 A Low-grade adenocarcinoma of a minor salivary gland involving the nasopharynx, infratemporal fossa, middle cranial fossa, cavernous sinus with encasement of the carotid artery, and sphenoid sinus in a 48-year-old female. B Postoperative CT scan 1 year later showing the operative cavity filled with the temporalis muscle flap Fig. 2 A Low-grade adenocarcinoma of a minor salivary gland of the nasopharynx of a 64-year-old male spreading into the posterior ethmoid and sphenoid sinuses and parasellar region. B Postoperative CT scan 6 months later showing the temporalis muscle flap in the operative cavity

Three forms of surgical treatment were used: the subtemporalreauricular infratemporal fossa approach as described by Sekhar et al. [10, 11] (2 cases), the subtemporal approach with facial translocation [6] (15 cases) and the transmandibular approach (3 cases). In addition, 14 patients required craniectomy. For well-lateralized tumors, involving only a lateral wall of the nasopharynx and the infratemporal fossa, the subtemporal-preauricular approach was used. In more extensive tumors, with extensive involvement of the nasopharynx or progression to the nasal cavity, sphenoid and clivus, a facial translocation approach was chosen. Patients with extensive nasopharyngeal tumors involving the upper part of the lateral wall of the oropharynx underwent a infratemporal transmandibular approach, sparing the mandible (two cases) or with hemimandibulectomy (one case). In these latter patients a pectoralis major myocutaneous flap was used to seal the extensive surgical defect. When disease surrounded the internal carotid artery a preoperative evaluation was done to assess the risk for cerebral infarction should carotid sacrifice be required. Testing was performed with carotid compression and electroencephalography, single photon emission computed tomography and transcranial Doppler ultrasonography.

Results T u m o r e x c i s i o n was total in all but three patients. These latter patients failed p r e o p e r a t i v e tests for carotid exclusion (two cases) or s h o w e d a limited i n v o l v e m e n t o f the brain stem through the trigeminal root (one case). T h e s e patients were m a n a g e d with p o s t o p e r a t i v e r a d i o t h e r a p y using a linear accelerator or g a m m a - k n i f e to treat small tumors remnants. In addition to these patients, six others were irradiated postoperatively.

Defects in the dura were reconstructed with L y o d u r a | or pericranial grafts in seven patients. Temporalis muscle flaps were utilized in all patients to seal the operative cavity. The m o s t frequent p o s t o p e r a t i v e complication, w o u n d infection, occurred in six patients, two o f w h o m develo p e d an o s t e o m y e l i t i s o f the o r b i t o z y g o m a t i c segment. Other c o m p l i c a t i o n s included c e r e b r o s p i n a l leaks (4), p n e u m o n i a (3), o p h t h a l m o p l e g i a (3), meningitis (1), and b r e a k d o w n o f the carotid artery (1). Two patients died as a result o f p o s t o p e r a t i v e c o m p l i c a t i o n s , resulting f r o m p n e u m o n i a (one case) and carotid h e m o r r h a g e (one case). Surgical m o r b i d i t y i n c l u d e d facial and tongue n u m b ness b e c a u s e o f the division o f the m a n d i b u l a r and m a x i l lary nerves, t e m p o r o m a n d i b u l a r j o i n t dysfunction w h e n the m a n d i b u l a r c o n d y l e was resected, and i n c o m p l e t e rec o v e r y o f the frontal branch of the facial nerve despite microsurgical reanastomosis. The only cosmetic defect was d e p r e s s i o n in the t e m p o r a l region caused b y temporalis m u s c l e flap rotation. A d d i t i o n a l surgery to correct a c o m p l i c a t i o n was required in two patients to close a c e r e b r o s p i n a l fluid l e a k and was done endoscopically. A parascapular free flap was used to repair a fistula b e t w e e n the z y g o m a t i c region and oral c a v i t y resulting from o s t e o m y e l i t i s of the m a l a r bone. To date, one patient with a l o w - g r a d e a d e n o c a r c i n o m a has died from distant metastases, another from unrelated causes, and three are alive with local disease. O n e patient with an a d e n o i d cystic c a r c i n o m a had t u m o r recur through

S 167 Fig. 3 A Perineural spread of a recurrent undifferentiated carcinoma into the cavernous sinus and prepontine cistern along the trigeminal nerve in a 45-year-old male. B Postoperative CT scan 1 year later showing no rests of the tumor Fig. 4 A Adenoid cystic carcinoma involving the nasopharynx and infratemporal fossa of a 30-year-old female. Tumor has progressed into the sphenoid sinus and middle cranial fossa. B Postoperative MRI 3 year later. There are no signs of recurrence; the temporalis muscle is lining the operative cavity. Fig. g A Giant juvenile nasopharyngeal angiofibroma in a 10-year-old male. Tumor involves the infratemporal fossa, sphenoid sinus and parasellar region with displacement of the carotid artery. B Postoperative CT scan 2 years later with no signs of recurrence

perineural spread in the petrous apex and parasellar region 3 years after surgery, with tumor successfully resected by a subtemporal transcavernous approach. N o n e of the juvenile angiofibromas have recurred as yet.

Discussion A n u m b e r o f anterior and lateral approaches to neoplasms within the infratemporal fossa have been reported during the past several years. The access obtained by anterior approaches is c o m p r o m i s e d by the long working distance required and is limited laterally in large tumors. This m a y prevent tumor removal from the peritubal space and control o f the internal carotid artery. Therefore, transmandibular approaches with [9] or without [7] mandibulec-

t o m y are required when tumors of the tonsillar region extend into the infratemporal fossa or when nasopharyngeal carcinomas extend into the tonsillar region. Other techniques have been described that expose the skull base and the nasopharynx from superior and lateral directions [1, 8, 10]. Exposure from the superior direction is produced largely by extradural temporal lobe retraction rather than by removal of bone from the skull base. W h e n there is no intracranial invasion, drilling the r o o f of the infratemporal fossa from below m a y suffice to remove tumor. In cases with intracranial progression, especially with tumor encasement of the internal carotid artery, the advantages o f a superior exposure are clear. In contrast, an infratemporat approach type C [2] will also require a subtotal petrosectomy.

S 168 The facial translocation approach [6] is well suited for management of extensive tumors in the paracentral skull base, especially when there is substantial extracranial tumor and tumor involves the nasal cavity. It allows the surgeon an exposure that is not easily obtainable by other procedures. When necessary, a subtemporal craniectomy permits exposure of the floor of the middle fossa and cavernous sinus. Taking these factors into account, this technique was used in most of our patients with nasopharyngeal tumors. Only when limited invasion of the nasopharynx was found, with no involvement of the nasal cavity and maxillary sinus, was the subtemporal-preauricular infratemporal approach employed. A cosmetic defect produced was a depression in the temporal region caused by temporalis muscle flap rotation, but this was minimized with free-fat grafts. When a facial translocation was added, the possibility of osteomyelitis or late bone resorption existed, as well as epiphora due to nasolacrimal duct obstruction. The variability of histological types of tumors in the nasopharynx, their uncommon presentations, and the small number of cases and follow-up in the few series published make it difficult to draw conclusions on longterm prognosis. The most common benign tumor involving the floor of the middle fossa from below is nasopharyngeal angiofibroma. At presentation, 15-20% of the patients have radiographic evidence of widening of the superior orbital fissure and displacement of the intracavernous carotid artery. Frontotemporal craniotomy followed by lateral rhinotomy [5] and the infratemporal approach type C [2] has the disadvantage of high rates of incomplete removal. In contrast, the infratemporal facial translocation approach does not damage the temporal bone and provides greater access to the orbital apex, superior parts of the tumor, nasopharynx and nasal cavity. With this approach complete excisions have been achieved in five patients in our series, with no significant morbidity. The 10-year survival rate for adenoid cystic carcinoma at any site is reported to be 22% [13]. In the series published by Shotton's group [12], 5 of 13 patients with adenoid cystic carcinoma of the skull base and nasopharynx followed for between 7 and 15 years had no sign of recurrence. The review period for the remaining 8 cases did not exceed 4 years, with one patient dead and another alive with disease. Our experience also suggests some confidence in our ability with the technique of infratemporal dissection to control such tumors permanently at the base of the skull. The role of surgery in the management of malignant nasopharyngeal and parapharyngeal tumors involving the floor of the middle cranial fossa is not well established. The results of the infratemporal fossa removal of 13 recurrent nasopharyngeal carcinomas after radiotherapy, reported by Fischet al. [3], are encouraging for T1 and T2 tumors, with six patients alive without disease at least 2 years after surgery, while those patients with more advanced stages died. When total resection is achieved, local recurrence is not very common. However, patients with highly malignant lesions fare poorly, due to the development of metastatic disease [ 11 ].

The mortality rate in our series due to postoperative complications was 10%. One patient with an extensive squamous cell carcinoma and encasement of the internal carotid artery who failed preoperative tests for carotid exclusion was operated on to debulk the tumor as much as possible before treatment with radiation therapy. The carotid artery was dissected free from tumor in the lateral aspect of the cavernous sinus, after which tumor was resected subtotally. The patient had a massive hemorrhage from the carotid artery 1 week later after the temporalis muscle flap used for reconstruction necrosed and failed to exclude the artery from the nasopharynx. Another patient succumbed to aspiration pneumonia, local infection and uncontrolled sepsis. The danger of carotid artery rupture contraindicates the use of operative approaches through the upper aerodigestive passage (such as the transmandibular approach), which may leave arteries at risk to the bacterial flora of these areas at the end of the operation. When such approaches expose major vessels, these should be protected with a vascularized flap. Infection was a common complication in our cases but, except for the case reported above, was in general readily treatable with antibiotics and did not represent a major clinical problem.

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