8.16\ Temporal Bone Resection

8.16.1\ Discussion

Treatment of external auditory canal malignancies will often include temporal bone resection. Usually these cases involve squamous cell carcinoma of the external ear, but sometimes parotid malignancies that secondarily extend into the ear and temporal bone. Temporal bone resection is typically classified as lateral, subtotal, or total (radical), some of which are depicted in Figs. 8.74 and 8.75 and listed in Table 8.3. Lateral temporal bone resection involves en bloc removal of the tympanic membrane and entire external auditory canal and is appropriate for tumors limited to the external auditory canal that have not penetrated the middle ear or mastoid. As a consequence of lateral temporal bone resection, the temporomandibular joint is rendered continuous with the tympanomastoid space, while mastoidectomy and auriculectomy

a

Fig. 8.74  Lateral temporal bone resection. Postoperative axial (a) and coronal (b) CT images demonstrate essentially complete resection of the tympanic bone and ossicles. The temporomandibular joint

is continuous with b tympanomastoid defect.

The facial nerve is preserved, but skeletonized (arrows). The inner ear structures are also preserved. A radial forearm free flap has been packed into the surgical cavity

defects are also present. Subtotal temporal bone resection involves extension of lateral temporal bone resection margins to include the middle ear and mastoid structures, the facial nerve, and the labyrinth. Total temporal bone resection involves further extension of subtotal temporal bone resection margins to include the sigmoid sinus/jugular bulb and the intrapetrous carotid artery, but this radical procedure is almost never performed in the modern era. All types of temporal bone resection may be extended to also include additional resection of adjacent involved structures, such as the mandibular condyle or dura. Parotidectomy and neck dissection are usually performed alongside temporal bone resection, and reconstruction may involve primary closure with or without a skin graft if the defect is small, but most often require a myocutaneous flap. Imaging plays an important role in the postoperative follow-up for tumor recurrence (Fig. 8.76). This may involve a combination of CT, MRI, and PET.

Fig. 8.75  Subtotal temporal bone resection. Axial CT head images (a, b) show left subtotal temporal bone resection with myocutaneous flap reconstruction. Labyrinth is absent. Since the facial nerve was sacrificed, an eyelid

weight was implanted. Axial (c) and coronal (d) temporal bone CT images show extensive resection of the temporal bone structures, including the expected course of the facial nerve

Table 8.3  Types of temporal bone resection

a

b

Fig. 8.76  Tumor recurrence after lateral temporal bone resection. The patient has a history of squamous cell carcinoma. Axial CT image (a) shows subtle soft tissue attenuation in the resection cavity that extends into the parapharyngeal space (arrows) and displaces the flap laterally. The corresponding PET image (b) shows considerable hypermetabolic activity within the lesion (arrows), which is now very conspicuous. There is normal activity within the cerebellum