TUMOR CONSIDERATIONS

The incidence of tumors of the temporal bone is 200 new cases per year with a frequency of 6 cases per 1 million. Squamous cell carcinoma accounts for 86% of these tumors. Possible etiologic factors include industrial exposure to petroleum-based products, topical disinfectants, and chronic infection. Basal cell carcinoma, adenoid cystic carcinoma, adenocarcinoma, and ceruminous carcinoma occur less frequently.^3–5 Tumors of mesenchymal origin are as rare, with rhabdomyosarcoma occurring most frequently.⁶ Salivary gland tumors can originate from ectopic rests of salivary tissue within the middle ear (pleomorphic adenoma has been described in that location), or from minor salivary glands within the EAC, but both are rare.⁷

Salivary gland tumors are more likely to involve the temporal bone through direct extension from the parotid gland. The anatomic relationship between the temporal bone and parotid gland is responsible for this tendency. The parotid gland is located in close proximity to the mastoid and tympanic portions of the temporal bone. It communicates directly with the cartilaginous EAC through the fissures of Santorini and foramen of Huschke.⁸ The stylomastoid foramen, carotid canal, jugular foramen, petrotympanic fissure, and eustachian tube provide avenues for intratemporal extension. In primary temporal bone carcinoma, these anatomic pathways are particularly significant as routes for extension beyond the temporal bone to the adjacent parotid tissue and soft tissue at the base of the skull base.

In rare cases of temporal bone involvement by benign tumors of the parotid gland, symptoms of a facial mass, trismus, or compression of the parapharyngeal space by tumor usually precede temporal bone involvement.⁹ Additionally, benign masses have a tendency to compress or remodel adjacent tissue, rather than invade it. This tendency allows for extirpation of a benign parotid neoplasm, in some cases, without requiring a formal temporal bone resection. These lesions can be removed through traditional parotidectomy techniques. Disarticulation of the mandibular condyle, resection of the EAC, or mastoidectomy may be necessary to assist with resection. Pleomorphic adenoma of the tail of the parotid gland can manifest as a subcutaneous mass of the floor of the lateral portion of the EAC. This situation is best managed with combined superficial parotidectomy with mastoidectomy and postauricular canalplasty.

Temporal bone involvement by malignancies of salivary gland origin is aggressive and involves adjacent tissue more readily. Tumors can develop insidiously and relatively asymptomatically, with 75% manifesting with a painless mass and only 6% to 13% manifesting with facial nerve palsy. Symptoms may not be present until after temporal bone invasion has occurred. Pain, dysphagia, and dysphonia can occur after direct invasion of the skull or involvement of the lower cranial nerves at the jugular foramen. Direct extension into bone, fissures, and foramina are potential routes of spread. Mass lesions of the poststyloid parapharyngeal space can traverse the carotid canal and jugular foramen, and neurotrophic tumors, such as adenoid cystic carcinoma, follow the facial nerve as an avenue toward the stylomastoid foramen. Carcinoma of the auricle, anterior scalp, or face that has spread to the intraparotid lymphatics can involve the temporal bone in a similar fashion. In a review of 27 cases of advanced and recurrent parotid neoplasms requiring temporal bone resection, Leonetti and colleagues⁹ found that adenocarcinoma occurred most commonly followed by adenoid cystic carcinoma and mucoepidermoid carcinoma.

Malignancies involving the temporal bone present a formidable problem. Without treatment, these lesions result in a high incidence of morbidity and almost certain death. Extension into the otic capsule and petrous bone can result in hearing loss, vestibulopathy, cranial neuropathies, and hemorrhage. Malignant spread into the middle and posterior fossa and extension into the petroclival region or cavernous sinus portend a grim prognosis even with aggressive surgical efforts. In cases of distant metastatic disease, a temporal bone resection may still be indicated for palliation.

HISTORY AND PHYSICAL EXAMINATION

A high index of suspicion by the examiner is necessary for prompt diagnosis and treatment in temporal bone carcinoma. Symptoms of fullness, pain, or trismus without clear explanation or rapid resolution are suspicious for carcinoma. Refractory pain is a hallmark of temporal bone carcinoma. An unexplained mass of the pinna, ear canal, or middle ear should prompt closer evaluation. An insidious symptom of carcinoma that frequently causes a delayed diagnosis is persistent ear drainage. Before the advent of computed tomography (CT), most temporal bone carcinomas were diagnosed after mastoidectomy for presumed chronic otitis media. Such nononcologic intervention frequently resulted in spread of the lesion to adjacent soft tissue structures.

BIOPSY

The only way to diagnose temporal bone carcinoma definitively is by biopsy. Although it is possible to obtain a biopsy specimen of an exuberant lesion of the EAC in the office, we recommend imaging before performing any deep tissue biopsies or removing any soft tissue lesions of the middle ear to prevent inadvertent damage to the carotid, jugular bulb, or facial nerve. False-negative biopsy specimens are an important consideration in temporal bone carcinoma. These lesions are often secondarily infected, and superficial biopsy specimens may reveal only chronic inflammatory changes. If initial biopsy results are negative, we recommend performing deeper tissue biopsies in an operating room to ensure that an adequate sample has been obtained.

DIAGNOSTIC TESTS

Imaging studies and audiometric testing are crucial. Magnetic resonance imaging (MRI) and CT provide accurate information helpful in the staging of disease and determining the extent of resection needed. A preoperative hearing assessment establishes a functional baseline, the need for postoperative middle ear reconstruction when appropriate, and the potential for postoperative deficits. Angiography should be performed in all cases in which the carotid artery is at risk. When carotid resection is anticipated, cerebral blood flow analysis should be used to determine resectability and the need for revascularization. Consideration should also be given to embolization when intraoperative hemorrhage is a concern. When the work-up is complete, proper TNM staging can occur, which provides a basis for discussing treatment options and prognosis with the patient.

The close proximity of vital structures within and adjacent to the temporal bone requires an accurate assessment of the involved anatomy. CT and MRI are indispensable in this regard. The ability of CT to detail bony structures and the superb soft tissue contrast offered by MRI play complementary roles during the work-up. Together, CT and MRI are helpful in establishing tumor extent, the involvement of critical structures, and the best surgical plan.¹⁰

The use of high-resolution CT with fine cuts is recommended. Images with a thickness of 0.625 to 1.25 mm produce the best assessment of the skull base. Direct axial and coronal scans should be obtained. When advanced scanning technologies are available, reconstructed images provide resolution that is equivalent to the original data set. CT is essential to preoperative staging. Arriaga and colleagues¹¹ showed that CT can “achieve 98% accuracy in predicting pathologic involvement in temporal bone resection specimens.” CT scans have limitations, however. Distinguishing mucosal inflammation from tumor and the extension of tumor without bony erosion remains difficult. In previously operated areas, positron emission tomography (PET) combined with CT has proven useful for distinguishing scar from neoplasm in identifying tumor recurrence and guiding treatment.¹²

MRI should be used to examine tumor relative to dura, brain, cerebrospinal fluid, and skeletal muscle. MRI also offers the advantage of imaging in multiple planes. Multiplanar imaging is useful when evaluating lesions that traverse the skull base through direct extent or perineural spread. T1 and T2 fat-saturated sequences should be obtained. T1 images help to determine spatial relationships and bone marrow involvement, whereas T2 images with fat saturation help to delineate tumors that enhance brightly. Postgadolinium T1-weighted images with fat saturation should also be obtained to determine the presence and extent of perineural involvement. This involvement can manifest as foraminal widening or enhancement, replacement of fat density, or increased signal intensity.

Audiologic testing shows the functional status of the middle and inner ear. This information is useful during surgical planning and preoperative patient counseling. Conductive losses may be attributable to the presence of a malignancy in the external or middle ear. Anacusis, tinnitus, and vertigo suggest inner ear involvement. If a reduction or elimination of hearing is anticipated, the patient should be informed in advance. Ossicular chain reconstruction or a bone-anchored hearing aid may be indicated when conductive hearing is sacrificed, but sensorineural hearing is spared.

A four-vessel angiogram with venous runoff should be used in cases of carotid encasement, or when disease mandates dissection of the petrous carotid. Arterial stenosis and contour irregularity at the site of the lesion suggest malignant involvement. Close inspection of the carotid canal on CT and CT angiography is useful for carotid assessment. Temporary balloon occlusion coupled with a cerebral blood flow quantification study helps to determine when carotid sacrifice would be tolerated. Quantification studies include PET, functional MRI, and xenon-CT. Xenon-CT is the best-studied modality.¹³ An occlusional cerebral blood flow less than 30 mL/100 g/min requires carotid bypass with prophylactic or intraoperative saphenous grafting or consideration of preoperative carotid stenting.¹⁴ Cerebral blood flow less than 30 mL/100 g/min or the development of neurologic symptoms during the test indicates a high risk of perioperative stroke. These findings either preclude the surgical option or require that prophylactic revascularization be done if surgery is performed. The venous side of imaging must not be ignored. If the torcular Herophili is not patent, permitting venous drainage from the ipsilateral sigmoid-transverse system to the opposite sigmoid-transverse-jugular system, venous infarction may occur. Specific attention should be focused on the adequacy of contralateral venous drainage.

STAGING

The American Joint Committee on Cancer states that a staging system should provide a sound basis for therapeutic planning for cancer patients by describing the survival and resultant treatment of different groups in comparable form. A lack of uniformity regarding preoperative staging and treatment plans made the study of temporal bone cancer difficult. This situation has changed with the demonstration that CT accurately predicts the degree of neoplastic involvement. The supplementation of these observations with clinical findings enabled the formation of a reliable system for staging carcinoma of the EAC.¹¹ Attempts to modify this system have been made. Moody and coworkers¹⁵ proposed upstaging patients with preoperative facial nerve paralysis or paresis to T4 status when the primary tumor originates in the EAC. They proposed that the extension of tumor through tissue separating the facial nerve and EAC and tumor involving the horizontal segment of the nerve are ominous signs.¹⁵ Although this and other modifications to the original system by Arriaga and colleagues¹¹ have been suggested, the original system has provided a useful framework for staging these lesions (Table 3-1), and validation of the various systems is still pending.

TABLE 3-1 Arriaga—University of Pittsburgh Tumor Lymph Node Metastasis Staging System Proposed for Squamous Cell Carcinoma of the External Auditory Canal

This system can be used to plan the surgical management of the temporal bone when involved secondarily by a cancer of the parotid gland. Although the data are not as clear for salivary gland cancers or pinna lesions extending to the temporal bone as for primary temporal bone lesions, the same staging criteria should be applied to decisions regarding the extent of the anatomic resection and the need for radiation therapy. Patients can be counseled about prognosis and survival based on results with primary cancer arising in the temporal bone, while carefully evaluating the status of the primary source of origin and possible metastases to cervical lymphatics.

SURGICAL TREATMENT

Surgery with postoperative radiation is the principal treatment for temporal bone carcinoma. The surgical procedure depends on the extent of disease because the medial extension of tumor dictates the aggressiveness: partial temporal bone resection, subtotal temporal bone resection, or total temporal bone resection. When tumors involve the temporal bone secondarily through direct extension, temporal bone resection accompanies the surgical management of the primary tumor. Similarly, if parotid gland involvement is likely from a primary temporal bone lesion, parotidectomy is also indicated.

Partial temporal bone resection includes removal of the entire external auditory meatus. It is indicated for cancer of the temporal bone that is limited to the external canal. The facial nerve, stapes, and promontory provide the medial limit of resection. The incisions and soft tissue management for all temporal bone resections depend on the planned management of the pinna. If the pinna is extensively involved and is to be sacrificed, a postauricular incision combined with a preauricular incision permits excision of the pinna—usually the pinna is resected in continuity with the temporal bone resection and parotidectomy specimen. If the pinna can be preserved, a circumferential incision around the soft tissue of the ear canal is performed, and the opening is sutured closed to prevent contamination by tumor spillage during manipulation of the specimen (Fig. 3-1).

FIGURE 3-1

The actual temporal bone resection begins by performing a complete mastoidectomy with accurate identification of the tegmen mastoideum and sigmoid sinus. The course of the facial nerve is dissected by exposing it with careful drilling of the fallopian canal from the lateral semicircular canal to the stylomastoid foramen. An extended facial recess approach provides wide access to the middle ear space by following the fibrous annulus inferiorly as the anterior limit of the dissection. Inferiorly and superiorly, the objective is to bring the dissection into the soft tissues of the glenoid fossa. As the inferior dissection proceeds anteriorly, the surgeon must consider the position of the jugular bulb and carotid artery. Usually the level of the fibrous tympanic annulus is safely lateral to the important vascular structures; however, preoperative CT imaging and intraoperative vigilance are necessary to avoid injury to those vessels. Superiorly, the zygomatic air cells are also dissected, and drilling proceeds superiorly from the antrum toward the zygomatic root, and through the epitympanum to the soft tissue of the temporomandibular joint. Superior to the EAC, the dissection proceeds lateral to the incus and malleus, and the surgeon takes care to avoid middle fossa dura by remaining close to the superior aspect of the EAC.

When the superior and inferior approaches to the glenoid fossa have been completed, the incudostapedial joint is separated; the tensor tympani is cut, and the ligamentous attachments of the ossicles are divided. At this point, the anterior portion of the external canal is its only remaining attachment (Figs. 3-2 and 3-3). This bone is fractured free of the carotid with gentle pressure or tapping with an osteotome. If a chisel is used, it is important to angle the instrument lateral to the carotid so that inadvertent injury of the vessel can be avoided. When the specimen has been removed, and the middle ear has been fully exposed, the eustachian tube is obliterated by filling it with muscle or fascia.

FIGURE 3-3

During the procedure, it is important to remain cognizant of the tumor, taking care to avoid it during the dissection. While drilling the epitympanum, it is important to remain lateral to the geniculate ganglion and medial to the annulus. An intact tympanic membrane should be preserved with the specimen for tumors limited to the EAC; this reduces the likelihood of tumor spillage. When involvement of the facial nerve is present, specimens of the proximal and distal margins should be examined histologically with sufficient tissue resection until the margins are free of tumor.

If the nerve is sacrificed, an interposition graft connects the proximal and distal tumor-free portions of the nerve. The sural nerve and the greater auricular nerve serve as excellent donor sites. The greater auricular nerve is used more often because of its proximity to the surgical field, but if there is malignant lymphadenopathy in the neck, the sural nerve should be used instead. Care is necessary during graft orientation to position the graft so that regenerating fibers are not lost through side branching, orienting the graft with the distal end of the graft in apposition with the proximal segment.

If the parotid gland is involved secondarily from extension of a temporal bone carcinoma or as the primary lesion that has extended to the temporal bone, the involved parotid tissues should be removed in continuity. In contrast to most decision making in surgical otology, the primary objective is an oncologically complete resection with clear margins; functional considerations such as hearing function and facial nerve function are secondary in priority. Tumor involvement of the facial nerve, deep lobe of parotid, or glenoid fossa necessitates a more aggressive resection. Gross tumor involvement of the glenoid is best managed by simultaneous resection of the mandibular condyle and zygomatic root, which facilitates dissection of the intratemporal and parapharyngeal spaces, and prevents the violation of soft tissue attachments between the parotid, temporomandibular joint, and EAC.

Consideration should also be given to management of the cervical lymphatics. Generally, primary temporal bone cancers rarely metastasize to the cervical lymphatics. Secondary involvement of the parotid by a primary temporal bone carcinoma and primary cancers of salivary gland origin have inherently different lymphatic drainage than carcinoma limited to the temporal bone, however, making dissection of the cervical lymph nodes prudent.

Subtotal temporal bone resection is necessary if the middle ear or facial nerves are involved. Involvement of the middle ear space requires a subtotal temporal bone resection. The dissection extends medially into the otic capsule and petrous portions of the temporal bone to obtain negative margins. The medial extent of dissection is defined by the internal auditory canal. At this extent of tumor involvement, adherence to the ideal of an en bloc resection is affected by the three-dimensional anatomy of the temporal bone. The technical steps of a subtotal temporal bone resection depend on the exact location of tumor involvement, but may result in piecemeal removal of the most medial extent of tumor with frozen section control.

It is most practical to begin with an en bloc partial temporal bone resection, and then adjust the resection medially. If resection of the jugular bulb or extensive carotid dissection is planned, control of the internal carotid artery and jugular vein is obtained inferiorly. Anteriorly, the vertical portion of the petrous internal carotid artery is identified by drilling away the cochlea and hypotympanum. When resection of the sigmoid sinus and jugular bulb is necessary, careful planning of handling these vascular structures limits unnecessary blood loss. The sigmoid must be occluded proximally, and the jugular vein must be ligated distally. If dural entry is planned, the sigmoid can be ligated with sutures by exposing the dura anterior and posterior to the sigmoid sinus. Alternatively, bone can be preserved from the midportion of the sigmoid and proximally toward the sigmoid-transverse junction.

Absorbable knitted fabric (Surgicel) can be packed extraluminally to occlude the sinus. Brisk bleeding from the inferior petrosal sinus and condylar vein occurs with opening of the jugular bulb, and the surgeon should be prepared with additional Surgicel packing. Although the initial packing involves significant material, the surgeon can gradually remove most of the packing leaving only the small portions occluding the openings of the inferior petrosal sinus and condylar vein in the bulb, and limit the risks to the lower cranial nerves in the pars nervosa of the jugular bulb from excessive packing and pressure. An additional strategy to prevent bleeding from the jugular bulb is preoperative coil embolization of the openings of the inferior petrosal sinus and condylar vein.¹⁶ The final resection margins proceed along the floor of the middle fossa connecting the glenoid fossa, internal auditory canal, and posterior-superior mastoid.

When the cancer has progressed beyond the limits of a subtotal temporal bone resection, a total temporal bone resection may be indicated. This topic is addressed in more detail in Chapter 4. Total temporal bone resection is rarely performed because of the high level of morbidity and a lack of well-documented survival benefit except in specific circumstances, such as verrucous squamous carcinoma, in which the aggressiveness is entirely local and indolent. The surgery involves freeing the temporal bone at the petrous apex. Before extirpation, the intratemporal portion of the internal carotid artery must be dissected to the foramen lacerum, and the internal jugular vein must be ligated. Sacrifice or reconstruction of the internal carotid artery may be performed based on the results of preoperative testing.

A subtemporal craniotomy is performed exposing the transverse sinus. The dura covering the cerebellum is incised, and the transverse sinus is ligated and divided near the superior petrosal sinus, being particularly careful to avoid injury to the vein of Labbé. The tentorium is divided sharply along the petrous bone in a plane superior and parallel to the superior petrosal sinus. The seventh and eighth cranial nerves are divided at the internal auditory canal. With the cerebellum retracted medially, an intradural incision is used to divide CN IX, X, and XI, and free the specimen at its posterior dural attachment. When the surrounding structures have been freed, a chisel is placed in the foramen ovale and directed posteriorly in a trajectory lateral to foramen lacerum; this frees the temporal bone at its apex.

RECONSTRUCTION

Reconstructive options should be explored preoperatively, but as in all oncologic surgeries, the reconstructive plan must never compromise the completeness of oncologic resection. Consideration should be given to the probable need for postoperative radiation, which should begin within 6 weeks of the resection. Additional concerns include cosmesis and the durability of the repair. Intraoperative findings might dictate a more complex reconstruction than anticipated. Careful planning improves the preparation for various potential defects. We prefer to involve a head and neck reconstructive surgeon for this portion of the procedure to avoid reconstructive consideration influencing the adequacy of the oncologic resection.

Partial temporal bone resections may be reconstructed with split-thickness skin grafts lining the mastoid and middle ear and sutured to the remaining soft tissue of the meatus. The graft should be placed to line the ear canal and mastoid bowl. Its medial extent can be carefully draped over the oval window or stapes remnant. Reconstruction of the ossicular chain can be done later. This reconstruction may require frequent postoperative care, however, and delayed healing can affect the timing of postoperative radiation. Vascularized temporal-parietal fascia or postauricular soft tissue (Palva flap) can be used to provide a vascularized bed for skin graft healing. Alternatively, the cavity can be obliterated with temporalis muscle or another rotational flap, such as a pectoralis major or sternocleidomastoid flap; however, this most likely would preclude reconstruction of the conductive hearing mechanism (Figs. 3-4, 3-5, and 3-6).

Subtotal temporal bone resection and total temporal bone resection require added soft tissue to obliterate dead space, prevent the leakage of cerebrospinal fluid, and provide protection against complications related to radiation therapy, the most serious of which is osteoradionecrosis. Smaller wounds involving resection of the pinna and external canal may be closed by a posterior scalp or cervicofacial advancement flap. If additional bulk is needed, a muscle or myocutaneous flap can be rotated on a vascularized pedicle, or inset via microvascular anastomosis.

Smaller defects may be amenable to closure using a temporalis muscle rotational flap. A trapezius, latissimus, or pectoralis major muscle rotational flap may become necessary as the size of the defect increases. Extensive defects may require a rectus abdominis muscle or perforator-based adipose free flap for closure. The arterial and venous anastomosis should be sutured to the external carotid artery and jugular vein. In wounds requiring additional skin, a split-thickness skin graft can be placed over the muscular portion of the reconstructive flap. If dura is resected, the dural defect and eustachian tube must be obliterated. This obliteration is accomplished with abdominal fat or free tissue transfer, and serves to shield the central nervous system from environmental insult.

COMPLICATIONS

Hemorrhage is a common risk in temporal bone resection. The otologic surgeon should be very familiar with the different techniques to control unplanned venous bleeding from the sigmoid sinus, superior petrosal sinus, and jugular bulb. With the sigmoid sinus, gentle pressure with absorbable gelatin sponge (Gelfoam) or Cottonoid is usually adequate. Great care must be exercised to not allow packing to dislodge within the lumen of the sigmoid sinus, unless the jugular vein has already been ligated in the neck. The jugular bulb does not respond to the same hemostatic strategies as the sigmoid sinus because the vessel wall is much thinner. Venous bleeding can be responsible for massive blood loss, and losses of 2500 mL can be encountered. As mentioned previously, excessive bleeding most commonly occurs at the inferior petrosal sinus, but this bleeding can be controlled with proper technique. The excessive use of packing at the jugular foramen can result in injury to CN IX, X, and XI, so this should be done with caution.¹⁷

Injury to the carotid artery should be managed with direct pressure and placement of temporary clips proximal and distal to the insult. Systemic and intra-arterial heparin should be given. The injury should be repaired with 8-0 monofilament suture. If minor leaks persist after closure, topical hemostatic agents can be applied. If successful repair of the vessel cannot be achieved, the preoperative balloon occlusion test should be used to guide management. Vascular surgery and neurosurgical consultation are imperative. If there is significant carotid involvement, preoperative stent placement has been suggested to avoid vascular complications.¹⁴

Facial nerve sacrifice or excessive manipulation of the nerve can result in facial asymmetry and inadequate eye closure. During the immediate postoperative period, the eye should be protected with lubrication, use of a moisture chamber, or mechanical lid closure. If the nerve is sacrificed, an interposition graft using the ipsilateral greater auricular nerve or sural nerve should be performed. If the greater auricular nerve is unavailable, the sural nerve can be used instead. Successful nerve interposition can restore function to a House-Brackmann scale grade III, but may take 12 to 18 months to occur. Placement of a gold weight implant or spring, lateral tarsorrhaphy, or tensing of the lower eyelid may be necessary during the reinnervation period. Facial-hypoglossal anastomoses can also help restore facial function. When lower cranial nerve deficits exist, this should be done with caution. A loss in the function of CN XII can have devastating consequences on an already impaired swallowing apparatus.

Tumor involving the jugular foramen may result in preoperative or postoperative paresis or palsy of CN IX and X. Such lesions can manifest in the airway and cause nutritional difficulties. Temporary or permanent tracheotomy and the placement of a gastrostomy tube may be necessary to compensate for the associated deficits. The combination of an insensate supraglottis, vocal fold motion impairment, and inadequate swallow reflex can result in aspiration with fatal consequences. Vocal fold medialization may restore safe deglutition. In more severe cases of swallowing or laryngeal dysfunction, a laryngotracheal separation may be necessary.

If dura has been excised or violated, the resulting defect must be repaired immediately. Primary closure should be instituted whenever possible. If necessary, the dural defect should be obliterated with fat, fascia, or free tissue transfer. Postoperative leakage of cerebrospinal fluid can be managed conservatively for 7 to 10 days with appropriate measures. Bed rest, elevation of the head of the bed, stool softeners, and placement of a lumbar drain can be useful in reducing intracranial pressure.¹⁸ If the leak persists beyond this period, the wound should be explored surgically, and closure of the dural defect should be reattempted.

RADIATION

Plans for the use of postoperative radiation should be made during the preoperative work-up. The use of adjuvant radiation should be anticipated whenever the middle ear is involved with disease. If intraoperative findings confirm the need for radiation, it should be administered in a timely fashion. Radiation therapy should not be delayed, or withheld in lieu of a recurrence, because this can result in decreased therapeutic efficacy. Closure of the surgical defect with viable, durable tissue is necessary to prevent development of osteoradionecrosis, which can be a devastating and sometimes fatal complication. In addition, careful postoperative hygiene and maintenance (cleaning and débridement with otomicroscopy) of the reconstructed area is essential to reduce likelihood of chronic infection that can predispose to osteoradionecrosis. Dosages typically range from 5000 to 6000 rad, and fields should be designed to include the area of resection and involved nodal groups.

The rarity of temporal bone malignancy makes the study of treatment protocols difficult, but encouraging results have been reported. T1 lesions successfully treated with surgery alone have a 95% 5-year survival, with no benefit from the addition of radiation. Some T2 and T3 lesions treated with radiation after complete surgical removal have shown an 85% 5-year survival. The 5-year survival of patients with more advanced lesions decreases to less than 50%. Cancer requiring a total temporal bone resection carries a dismal prognosis, with a 50% 1-year survival and reports of 0% 2-year survival.^5,6,19

CHEMOTHERAPY

The role of chemotherapy in the treatment of temporal bone malignancy has not been determined, but interest in its use is growing. Because of the low incidence and the histologic diversity of temporal bone malignancies, few meaningful studies have been conducted. Temporal bone malignancies of salivary gland origin, similar to salivary malignancies in other sites, do not usually respond to currently available chemotherapeutic agents. Squamous cell carcinoma of the temporal bone may respond to platinum-based agents, but typically the results are not durable, and other modalities must be used. For these reasons, most patients with temporal bone cancer are treated with surgery, radiation, or a combination of the two, and chemotherapy is usually reserved for palliation in patients with distant metastases or recurrences.

Nakagawa and coworkers² published data that suggest a possible role for preoperative chemoradiation therapy in the treatment of T3 and T4 squamous cell carcinoma when staged according to the Arriaga system. The radiation-enhancing effect of chemotherapy may be useful in reducing the tumor burden and improving control of the surgical margin. Nakagawa and coworkers² showed improved survival rates for T4 lesions not involving dura, pyramidal apex, carotid canal, or lymph nodes that are as good as survival rates in patients with T3 lesions. The poor outcomes associated with the treatment of advanced temporal bone malignancy mandate further investigation into the possible role of chemotherapy as a treatment modality.

REHABILITATION OF LOWER CRANIAL NERVE DEFICITS

The details of surgical rehabilitation of lower cranial nerve deficits are discussed elsewhere. Generally, in limited temporal bone resection, the function of CN IX, X, XI, and XII can be preserved. Their sacrifice has significant quality-of-life and function implications for speech, voice, and swallowing. In addition to involvement of a head and neck surgeon with expertise in laryngeal restoration, thyroplasty and palatal rehabilitation, team members should include speech-language pathologists with experience in diagnosing and treating lower cranial nerve dysfunction. Strategies such as modified barium swallow and flexible endoscopic evaluation of swallowing are important components of a comprehensive assessment.

The impact of radiation sequelae such as xerostomia on swallowing should not be underestimated.²⁰ Nonetheless, postoperative radiation is a crucial part of the comprehensive management of a patient with temporal bone carcinoma.

CONCLUSION

Successful management of temporal bone carcinoma depends on adequate pretreatment evaluation and staging. Most patients require limited temporal bone resection followed by postoperative radiation. In contrast to other otologic procedures, the management priorities in malignancy require that the otologic surgeon should ensure that the resection is oncologically sound, and consider hearing, vestibular, and facial function as secondary priorities.