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Lateral temporal bone resections
Lateral Temporal Bone Resections Jesus E. Medina, MD, Alfred O. Park, MD, J. Gall Neely, MD, B. Hill tmtton, MO, OklahomaCity,Oklahoma
Eighteen consecutive patients underwent a lateral temporal bone resection for the treatment of tumors originating in the auricle, the external auditory canal, the periauricular skin, or the parotid and were retrospectively analyzed. The different lateral temporal bone resections performed have been categorized into four types. The type I resection consists of the removal of the tympanic bone and the external auditory canal lateral to the tympanic membrane. The type II resection consists of the removal of the entire tympanic bone, the tympanic membrane, the incus, and the malleus, preserving the facial nerve and the inner ear. Type III resections remove, in addition to the those structures removed in type II resections, the distal facial nerve and fallopian canal, the mastoid tip, the styloid process, and the stylomastoid foramen. The type IV resection consists of the removal of only the mastoid tip and the inferior portion of the tympanic bone. When the techniques of lateral temporal bone resection are used appropriately, adequate surgical treatment of patients with selected advanced and recurrent malignant tumors of the external ear, the periauricular skin, and the parotid is possible with low morbidity and a high probability of local regional control.
dequate surgical resection of malignant tumors that originate in the external auditory meatus, the pinna, A the periauricular skin, or the parotid may require removal of the adjacent temporal bone. A subtotal resection of the temporal bone, an operation that has been dearly defined, is often performed in such cases [l,2]. However, the sequelae of this operation, i.e., loss of inner ear function and facial paralysis, and the perioperative morbidity associated with it have induced surgeons to perform various partial resections of the lateral portion of the temporal bone [3-5]. By removing only those portions of the temporal bone that are adjacent to the tumor or are Fromthe Departmentof Otorhinolaryngotogy,The Universityof Oklahoma Health SciencesCenter,OklahomaCity,Oklahoma. Requestsfor reprintsshouldbe addressedto JesusE. Medina,MD, Department of Otorhinolaryngology,Universityof Oklahoma, P.O. Box26901, OklahomaCity,Oklahoma73190. Presented at the 36th AnnualMeetingof the Societyof Head and Neck Surgeons,Washington,DC, May 19-22, 1990.
involved by it, these techniques can provide adequate margins of resection around selected tumors while preserving the middle ear, the inner ear, the facial nerve, or all three. The purpose of this report is to categorize the different lateral temporal bone resections and to describe their use in the surgical treatment of tumors of the external ear, the periauricular skin, and the parotid in a systematic approach that is designed to tailor the extent of the temporal bone resection according to the location and extent of the tumor. PATIENTS AND METHODS The basis of this report is a retrospective analysis of 18 consecutive patients who underwent a lateral temporal bone resection for the treatment of tumors originating in the auricle, the external auditory canal, the periauricular skin, or the parotid. These patients were treated at the University of Oklahoma-affiliated hospitals between July 1, 1982, and June 30, 1989. Prior to surgery, each patient was prospectively evaluated by an otologist and a head and neck oncologic surgeon. In addition to a detailed clinical examination, all patients had an audiogram and computed tomographic scan of the temporal bone. A lateral temporal bone resection was considered when a malignant tumor clinically and/or radiographically involved the postauricular sulcus skin, the concha, or the external auditory canal, or was contiguous with or invaded the tympanic bone, the mastoid cortex, or both, but did not invade the middle ear or any pneumatized space in the temporal bone. Surgery was carried out in a systematic, step-by-step manner designed to verify the extent of the tumor and to resect only those portions of the temporal bone that were either involved by the tumor or were immediately adjacent to it. Surgical techniques: The incisions were designed to encompass the tumor with grossly adequate margins and to either incorporate the pinna with the specimen or to allow its retraction anteriorly, posteriorly, or superiorly in order to expose the mastoid (Figure 1). When only the external auditory canal was resected, the incision used was a wide circumferential incision that included a cuff of skin and cartilage of the concha and extended superiorly into the temple and inferiorly into the neck in a way similar to a parotidectomy incision. A cortical mastoidectomy was performed, and the middle ear was entered through an extended facial recess approach. Any abnormal mucosa or suspicious tissue encountered in the mastoid or the middle ear was removed and examined by frozen section. If either gross or microscopic tumor was encountered, a subtotal resection of the temporal bone was performed, removing the facial nerve and the inner ear [1]. Otherwise, the bone lateral to the epitympanum was removed to the level of the root of the zygoma and into the temporomandibular joint. The bone about the
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Figure 1. Outline of surgical incisions to include the pinna or allow its retraction superiorly, posteriorly, or anteriorly.
hypotympanum, lateral to the facial nerve, was likewise removed in an anterior direction, again, to the level of and into the temporomandibular joint (Figure 2). These initial steps were performed, with minor variations, in every patient. The following steps varied according to the location and extent of the tumor. Type I lateral temporal bone resection: When the tumor originated in the concha or in the periauricular skin, but did not involve the skin of the external auditory canal grossly, did not infiltrate deeply into the parotid or
the temporomandibular joint, and did not involve the facial nerve, the tympanic bone was cut circumferentially in a plane lateral to the tympanic membrane (Figure 3). The complete circumference of the external auditory canal was cut with a drill into the temporomandibular joint. The condyle was not resected. If microscopic tumor extension to the capsule was suspected, the resected capsule was submitted for frozen section examination. The entire circumference of the medial margin of the skin of the external auditory canal was examined by frozen section; if tumor was found, a type II lateral temporal bone resection was performed. It is important to emphasize that the anterior canal wall, i.e., the posterior wall of the glenoid fossa, is resected. Type II lateral t e m p o r a l bone resection: This operation was performed when the tumor originated in the skin of the external auditory canal or extended grossly into it from either the pinna or the periauricular skin. After the initial steps described previously were completed, the facial recess was opened, the incus was disarticulated from the stapes, and the tensor tympani tendon was cut. The fallopian canal was identified, but not opened, from the geniculate ganglion to the stylomastoid foramen, and the chorda tympani was cut. The bone about the hypotympanum was removed in a plane medial to the tympanic annulus and just lateral to the jugular foramen and the carotid canal (Figure 4); the removal of the bone was carried up to the glenoid fossa. After completion of this step of the operation, the lateral portion of the temporal bone to be resected was only connected to the rest of the temporal bone by a thin plate of bone between the protympanum of the middle ear and the glenoid fossa in the area of the eustachian tube. This was easily fractured forward by gentle pressure on the bony canal, freeing the surgical specimen (Figure 4). The anterior osseous canal was again included with the specimen. Type III lateral bone resection: When the location
Figure 2. Lateral temporal bone resection. Initial steps performed in all patients. Left, diagram showing the temporal bone, the facial
nerve, the mandible, internal jugular vein, and internal carotid artery. Center, a cortical mastoidectomy has been performed. Right, bone removal has been extended anteriorly into the temporomandibular joint, superiorly (removing bone lateral to the epitympanum), and inferiorly (removing the bone about the hypotympanum, lateral to the facial nerve).
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Figure 3. Lateral temporal bone resection type I. Left, outline of the bone cuts in the external auditory canal (tympanic bone). Center, external auditory canal fractured forward. Note that the bone cut is performed just lateral to the tympanic membrane and the facial nerve. RIgM, remaining structures and defect after removal of surgical specimen.
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Figure 4. Lateral temporal bone resection type II. Left, outline of bone cuts in tympanic bone and potential extension through the neck of the condyle. Center, the tympanic bone with attached tympanic membrane, malleus, and Incus has been fractured forward. Right, remaining structures and surgical defect.
and extent of the tumor dictated the need to resect the entire tympanic bone, the stylomastoid foramen, and the facial nerve, as in the case of persistent or recurrent tumors following superficial parotidectomy, the bone cuts were performed in a plane medial to the fallopian canal, the stylomastoid foramen, and styloid process, which were included in the resected specimen. The jugular foramen and the internal carotid canal were the medial limit of the resection (Figure 5). T y p e IV lateral temporal bone resection: This type of resection was done when the tumor was adjacent only to the mastoid tip, the inferior aspect of the tympanic bone, or both. The external auditory canal lumen, the
tympanic membrane, and the middle ear structures were preserved while the inferior portion of the typanic bone and the mastoid tip were resected. Depending upon the clinical situation, the facial nerve and the styloid process could be resected or preserved (Figure 6). The resection of the lateral portion of the temporal bone was performed in conjunction with a parotidectomy, a partial mandibulectomy, a neck dissection, or a temporal craniectomy and resection of the glenoid fossa and the floor of the middle cranial fossa, depending upon the extent of the tumor. The resulting surgical defect was repaired with a temporalis muscle flap, a split-thickness skin graft, or both,
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Figure 5. Lateral temporal bone resection type III. Left, outline of bone cuts medial to the fallopian canal and potential extension through the neck of the condyle. Center, lateral portion of the temporal bone to be resected, including the styloid process, fallopian canal, and facial nerve, is fractured forward. Right, remaining structures and surgical defect.
Figure 6. Lateral temporal bone resection type IV. Left, outline of bone cuts through the mastoid tip and inferior portion of tympanic bone. Center, resected portion of the temporal bone displaced forward. Right, remaining structures and surgical defect.
whenever possible. Large defects, particularly those in which the dura or the internal carotid artery was exposed, were repaired with myocutaneous flaps. RESULTS The age of the 18 patients studied ranged from 43 to 89 years, with a mean age of 65 years. There were 16 men and 2 women. Histologically, the tumor was a squamous cell carcinoma in 11 patients, a basal cell carcinoma in 5, a poorly differentiated adenocarcinoma in 1, and a lymphoma in 1 patient. The latter was a patient with a lymphocytic lymphoma of the periauricular skin. Following treatment with chemotherapy and radiation therapy, he had a persistent painful ulceration that involved the skin
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and soft tissues of the pinna and the pre- and infraauricular skin. The tumor had not been previously treated in 7 patients, while 11 patients presented with either persistent or recurrent tumor after treatment outside of our institution. Previous treatment had consisted of surgery in six patients, radiation therapy in four patients, and combined surgery and postoperative radiation in one patient. A type I lateral temporal bone resection was performed in two patients. In one of these two, the tumor originated in the preauricular skin and had been previously treated with the Mohs' technique. The treating dermatologist was unable to obtain clear margins within the parotid. The resultant ulceration was adjacent to the osse-
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ous external auditory canal, but the skin of the canal was not involved. The other patient had a tumor that originated in the pinna and extended to within 1 cm of the external auditory canal, but the canal itself was univolved. A type II lateral temporal bone resection was performed in 10 patients. In five, the tumor originated in the skin of the external auditory canal. In three patients, the tumor arose from the preauricular skin and involved the underlying soft tissues, the parotid, and the external auditory canal. In one patient with a usual lymphoma, tumor and necrosis following chemotherapy and radiation widely involved the periauricular skin, the pinna, and the parotid. In one patient, the tumor orginated on the pinna; this was an exophytic, fungating lesion that did not appear to involve the skin of the external auditory canal, clinically or radiographically. Thus, a type I resection was performed, transsecting the tympanic bone and skin of the external auditory canal just lateral to the tympanic membrane. However, frozen section examination revealed tumor in the subepithelial plane at the resection margin near the tympanic membrane. Consequently, a type II resection was performed. A type III resection was performed in four patients. In one of these four, the tumor was a recurrent squamous cell carcinoma of the pinna that involved the external auditory canal, the preauricular skin, and the parotid. The remaining three patients had persistent or recurrent tumor in the parotid following a superficial parotidectomy done elsewhere. All of these patients had facial paralysis; in three patients, paralysis had developed as a result of the initial superficial parotidectomy. A type IV resection was done in two patients. One patient had a squamous cell carcinoma of the skin overlying the tip of the mastoid and the uppermost portion of the sternocleiodomastoid muscle. It had been previously treated unsuccessfully with the Mohs' technique. He then received radiation therapy (tumor dose 6,600 rad in 6 weeks), but the tumor persisted. A wide resection of the skin and the soft tissues of the area was performed in conjunction with a partial pinnectomy and a type IV lateral temporal bone resection in which the facial nerve and the external auditory canal lumen were preserved. The other patient had a superficial parotidectomy for a squamous cell carcinoma in the parotid. At the time of previous surgery, the tumor was found adjacent to the inferior aspect of the tympanic bone and surrounding the facial nerve at the level of the stylomastoid foramen; the patient was referred to us for definitive treatment. A total parotidectomy was performed in conjunction with a lateral temporal bone resection that included the mastoid tip, the inferior portion of the tympanic bone, the facial nerve, the stylomastoid foramen, and the styloid process. The temporal bone resection was performed in combination with a parotidectomy in 14 patients, a partial mandibulectomy in 4 patients, and a resection of the glenoid fossa and the floor of the middle cranial fossa in 2 patients. A cervical lymphadenectomy was done in 13 patients.
Postoperatively, one patient died of a cardiac arrhythmia. There were no other perioperative complications. The facial nerve was preserved in 13 patients. The inner ear was preserved in all patients; however, the type II and type III lateral temporal bone resections resulted in a pronounced ipsilateral conductive hearing loss. None of the patients developed vertigo. Seven patients received postoperative radiation. Follow-up ranged from 9 to 72 months, with a median of follow-up of 28 months. At last follow-up, 13 patients (72%) were alive and free of disease, 3 patients (17%) have died with distant metastases [2 of these 3 patients (11%) also had a local recurrence], and 1 patient (6%) is alive with distant metastases. COMMENTS It would appear from the results of this study that adequate surgical treatment of patients with selected advanced and recurrent malignant tumors of the external ear, the periauricular skin, and the parotid is possible with low morbidity and a high probability of local regional control when the diagnostic evaluation of these patients is performed in a systematic manner and the techniques of lateral temporal bone resection are used appropriately. Preservation of function is also maximized with this approach. The different lateral temporal bone resections performed in this study population have been categorized into four types. The type I resection consists of the removal of the tympanic bone and the external auditory canal lateral to the tympanic membrane. This type of lateral temporal bone resection has been referred to as a "sleeve resection" of the external auditory canal [6] and was briefly described by Jesse et al [7], who used it for the treatment of tumors that were localized to the external auditory canal and involved the bony portion of it. We would like to emphasize that "sleeve resection" does not, and should not, mean a resection of the skin of the external auditory canal alone. The type II resection consists of the removal of the entire tympanic bone, the tympanic membrane, the incus, and the malleus, preserving the facial nerve and the inner ear. Crabtree et al [4] described this type of resection as a means to perform a wide en-bloc resection of tumors of the external auditory canal that had invaded the bone of the external canal or mastoid, as long as the tumor extending into the mastoid "did not reach as deep as the mucosa of the middle ear or involve the facial nerve." The type III resection removes, in addition to the structures removed in the type II resection, the distal facial nerve and fallopian canal, the mastoid tip, the styloid process, and the stylomastoid foramen. Fisch and Mattox [5] refer to this technique as a total removal of the tympanic bone with subtotal petrosectomy, and they have described its use in the resection of tumors of the retromandibular fossa. The type IV resection consists of the removal of only the mastoid tip and the inferior portion of the tympanic bone. The external auditory canal, the tympanic mem-
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brane, and the middle ear are preserved. The facial nerve and the styloid process are removed when this technique is used for the treatment of tumors of the retromandibular fossa [5]; however, when resecting tumors of the retroauricular skin, a similar resection of the mastoid and tympanic bone can be performed without resecting the facial nerve or the styloid process. The decision to perform a lateral temporal bone resection and the decision as to what type of lateral temporal bone resection to perform is based upon the location of the tumor and the presence of tumor in certain critical areas of the temporal bone and surrounding structures, such as, the middle cranial fossa and the trigeminal ganglion, the middle ear and the aerated spaces of the mastoid, the medial portion of the external auditory canal, the facial nerve, the tympanic bone, and the temporomandibular joint. Unfortunately, it is not always possible to ascertain the presence or absence of tumor in these areas, even with a methodical preoperative assessment. Therefore, these operations must be performed in a systematic, step-by-step manner, verifying the presence and the extent of tumor in these critical areas. When intracranial spread of tumor is suggested by the preoperative evaluation, it may be advisable to begin the operation with a temporal craniotomy to assess the degree of intracranial involvement and to establish the resectability of the tumor. Intracranial spread of tumors about the ear can occur as a result of either direct extension through the floor of the middle cranial fossa or by perineural spread along the trigeminal nerve. In both instances, once the tumor reaches the dura, it can grow along the base of the skull with little resistance. Furthermore, if the trigeminal ganglion is found to be grossly involved by tumor, the prognosis is so poor that consideration should be given to discontinuing the procedure and using other forms of palliative therapy [8]. A lateral temporal bone resection should be discontinued if tumor is found in the middle ear or in the aerated spaces of the mastoid. Although in such cases, a radical mastoidectomy may accomplish a piece-meal resection of the tumor and may result in an occasional cure, particularly, when combined with postoperative radiation therapy [9], it is preferable to perform a subtotal resection of the temporal bone, if the condition of the patient permits it [2]. The circumferential margin of resection of the external auditory canal in a type I lateral temporal bone resection must be examined for the presence of tumor by frozen section. Tumors that involve the concha or the skin of the external auditory meatus can spread in the direction of the tympanic membrane in a subperichondrial-subperiosteal plane, underneath apparently normal skin and without deforming the external auditory canal. This phenomenon was observed in one of our patients. When this occurs, the tympanic annulus, tympanic membrane, and the malleus and incus are resected in a manner similar to a type II resection. The facial nerve was not resected in the patients in this study unless it was clinically and histologically involved
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by tumor. In patients in whom facial nerve involvement is obvious or suspected, the facial nerve must be exposed in its entirety in the mastoid. Note must be made of the macroscopic appearance of the nerve and a section of the margin must be submitted for examination by frozen section. The degree of involvement of the tympanic bone determines whether a type III or a type IV resection of the lateral portion of the temporal bone is necessary. When the tumor is only adjacent to the tip of the mastoid and the inferior portion of the tympanic bone, a type IV resection will provide an adequate margin of resection [5]. However, when tumor invasion of the tympanic bone is radiographically evident or it is discovered in the course of performing a type IV resection, the entire tympanic bone should be removed in conjunction with the tip of the mastoid, the facial nerve, and the styloid process (type III resection) [5]. Tumor involvement of the temporomandibular joint requires extending the lateral temporal bone resection to include the glenoid fossa, the mandibular condyle, and the floor of the middle cranial fossa [5]. It would appear that involvement of the temporomandibular joint by tumors about the ear is not common since it occurred in only two of our patients, both of whom had very extensive tumors. However, it must be emphasized that whenever tumor involvement of the joint was suspected in this series of patients, the lateral portion of the joint capsule was resected and examined by frozen section. This limited the indications for the more extensive resection of the base of the skull to those cases with histologically proven involvement of the temporomandibular joint. In sharp contrast with the perioperative morbidity associated with subtotal resection of the temporal bone, there were no perioperative complications related to lateral temporal bone resection in the patients reviewed in this study. Furthermore, since the inner ear was preserved in all patients, none of them exhibit postoperative vestibular dysfunction. Although this is a small series of patients, the low rate of local recurrence observed (11%) is noteworthy since most of these patients had either advanced, persistent, or recurrent tumors. In summary, the four types of lateral temporal bone resections described here can be used for the surgical treatment of selected malignant tumors of the ear, periauricular skin, and the parotid. Proper use of these techniques requires a methodical preoperative evaluation and a systematic intraoperative assessment of the extent of the tumor. The morbidity associated with the lateral temporal bone resections is low.
REFERENCES 1. Neely JG. Anatomic considerations of the medial cuts in the subtotal temporal bone resection. OtolaryngolHead Neck Surg 1982; 90: 641-5. 2. LewisJS, Parson H. Surgery for advancedear cancer.Ann Otol 1958; 67: 364-88. 3. Gacek RR, Goodman M. Management of malignancyof the
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temporal bone. Laryngoscope 1977; 87: 1622-34. 4. Crabtree JA, Britton BH, Pierce MK. Carcinoma of the external auditory canal. Laryngoscope 1976; 86: 405-15. 5. Fisch U, Mattox DE. Petrosectomy and facial rehabilitation in malignanttumors of the retromandibular fossa. In" Bull TR, Myers E, eds. Plastic reconstruction in the head and neck. London: Butterworths, 1986: 79-97. 6. Goodwin W J, Jesse RH. Malignant neoplasms of the external auditory canal and temporal bone. Arch Otolaryngol 1980; 106: 675-9.
7. Jesse RH, Healey JE Jr, Wiley DB. External auditory canal, middle ear, and mastoid. In: Maccomb WS, Fletcher GH, eds. Cancer of the head and neck. Baltimore: Williams & Wilkins, 1967: 412-27. 8. Mendenhall WM, Parsons JT, Mendenhall NP, Stringer SP, Cassissi N J, Million RR. Carcinoma of the skin of the head and neck with perineural spread. Head Neck Surg 1989; 11: 301-8. 9. Ward GE, Loch WE, Lawrence W Jr. Radical operation for carcinoma of the external auditory canal and middle ear. Am J Surg 1951; 82: 169-78.
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Eighteen consecutive patients underwent a lateral temporal bone resection for the treatment of tumors originating in the auricle, the external auditory canal, the periauricular skin, or the parotid and were retrospectively analyzed. The different lateral temporal bone resections performed have been categorized into four types. The type I resection consists of the removal of the tympanic bone and the external auditory canal lateral to the tympanic membrane. The type II resection consists of the removal of the entire tympanic bone, the tympanic membrane, the incus, and the malleus, preserving the facial nerve and the inner ear. Type III resections remove, in addition to the those structures removed in type II resections, the distal facial nerve and fallopian canal, the mastoid tip, the styloid process, and the stylomastoid foramen. The type IV resection consists of the removal of only the mastoid tip and the inferior portion of the tympanic bone. When the techniques of lateral temporal bone resection are used appropriately, adequate surgical treatment of patients with selected advanced and recurrent malignant tumors of the external ear, the periauricular skin, and the parotid is possible with low morbidity and a high probability of local regional control.
dequate surgical resection of malignant tumors that originate in the external auditory meatus, the pinna, A the periauricular skin, or the parotid may require removal of the adjacent temporal bone. A subtotal resection of the temporal bone, an operation that has been dearly defined, is often performed in such cases [l,2]. However, the sequelae of this operation, i.e., loss of inner ear function and facial paralysis, and the perioperative morbidity associated with it have induced surgeons to perform various partial resections of the lateral portion of the temporal bone [3-5]. By removing only those portions of the temporal bone that are adjacent to the tumor or are Fromthe Departmentof Otorhinolaryngotogy,The Universityof Oklahoma Health SciencesCenter,OklahomaCity,Oklahoma. Requestsfor reprintsshouldbe addressedto JesusE. Medina,MD, Department of Otorhinolaryngology,Universityof Oklahoma, P.O. Box26901, OklahomaCity,Oklahoma73190. Presented at the 36th AnnualMeetingof the Societyof Head and Neck Surgeons,Washington,DC, May 19-22, 1990.
involved by it, these techniques can provide adequate margins of resection around selected tumors while preserving the middle ear, the inner ear, the facial nerve, or all three. The purpose of this report is to categorize the different lateral temporal bone resections and to describe their use in the surgical treatment of tumors of the external ear, the periauricular skin, and the parotid in a systematic approach that is designed to tailor the extent of the temporal bone resection according to the location and extent of the tumor. PATIENTS AND METHODS The basis of this report is a retrospective analysis of 18 consecutive patients who underwent a lateral temporal bone resection for the treatment of tumors originating in the auricle, the external auditory canal, the periauricular skin, or the parotid. These patients were treated at the University of Oklahoma-affiliated hospitals between July 1, 1982, and June 30, 1989. Prior to surgery, each patient was prospectively evaluated by an otologist and a head and neck oncologic surgeon. In addition to a detailed clinical examination, all patients had an audiogram and computed tomographic scan of the temporal bone. A lateral temporal bone resection was considered when a malignant tumor clinically and/or radiographically involved the postauricular sulcus skin, the concha, or the external auditory canal, or was contiguous with or invaded the tympanic bone, the mastoid cortex, or both, but did not invade the middle ear or any pneumatized space in the temporal bone. Surgery was carried out in a systematic, step-by-step manner designed to verify the extent of the tumor and to resect only those portions of the temporal bone that were either involved by the tumor or were immediately adjacent to it. Surgical techniques: The incisions were designed to encompass the tumor with grossly adequate margins and to either incorporate the pinna with the specimen or to allow its retraction anteriorly, posteriorly, or superiorly in order to expose the mastoid (Figure 1). When only the external auditory canal was resected, the incision used was a wide circumferential incision that included a cuff of skin and cartilage of the concha and extended superiorly into the temple and inferiorly into the neck in a way similar to a parotidectomy incision. A cortical mastoidectomy was performed, and the middle ear was entered through an extended facial recess approach. Any abnormal mucosa or suspicious tissue encountered in the mastoid or the middle ear was removed and examined by frozen section. If either gross or microscopic tumor was encountered, a subtotal resection of the temporal bone was performed, removing the facial nerve and the inner ear [1]. Otherwise, the bone lateral to the epitympanum was removed to the level of the root of the zygoma and into the temporomandibular joint. The bone about the
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\
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Figure 1. Outline of surgical incisions to include the pinna or allow its retraction superiorly, posteriorly, or anteriorly.
hypotympanum, lateral to the facial nerve, was likewise removed in an anterior direction, again, to the level of and into the temporomandibular joint (Figure 2). These initial steps were performed, with minor variations, in every patient. The following steps varied according to the location and extent of the tumor. Type I lateral temporal bone resection: When the tumor originated in the concha or in the periauricular skin, but did not involve the skin of the external auditory canal grossly, did not infiltrate deeply into the parotid or
the temporomandibular joint, and did not involve the facial nerve, the tympanic bone was cut circumferentially in a plane lateral to the tympanic membrane (Figure 3). The complete circumference of the external auditory canal was cut with a drill into the temporomandibular joint. The condyle was not resected. If microscopic tumor extension to the capsule was suspected, the resected capsule was submitted for frozen section examination. The entire circumference of the medial margin of the skin of the external auditory canal was examined by frozen section; if tumor was found, a type II lateral temporal bone resection was performed. It is important to emphasize that the anterior canal wall, i.e., the posterior wall of the glenoid fossa, is resected. Type II lateral t e m p o r a l bone resection: This operation was performed when the tumor originated in the skin of the external auditory canal or extended grossly into it from either the pinna or the periauricular skin. After the initial steps described previously were completed, the facial recess was opened, the incus was disarticulated from the stapes, and the tensor tympani tendon was cut. The fallopian canal was identified, but not opened, from the geniculate ganglion to the stylomastoid foramen, and the chorda tympani was cut. The bone about the hypotympanum was removed in a plane medial to the tympanic annulus and just lateral to the jugular foramen and the carotid canal (Figure 4); the removal of the bone was carried up to the glenoid fossa. After completion of this step of the operation, the lateral portion of the temporal bone to be resected was only connected to the rest of the temporal bone by a thin plate of bone between the protympanum of the middle ear and the glenoid fossa in the area of the eustachian tube. This was easily fractured forward by gentle pressure on the bony canal, freeing the surgical specimen (Figure 4). The anterior osseous canal was again included with the specimen. Type III lateral bone resection: When the location
Figure 2. Lateral temporal bone resection. Initial steps performed in all patients. Left, diagram showing the temporal bone, the facial
nerve, the mandible, internal jugular vein, and internal carotid artery. Center, a cortical mastoidectomy has been performed. Right, bone removal has been extended anteriorly into the temporomandibular joint, superiorly (removing bone lateral to the epitympanum), and inferiorly (removing the bone about the hypotympanum, lateral to the facial nerve).
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Figure 3. Lateral temporal bone resection type I. Left, outline of the bone cuts in the external auditory canal (tympanic bone). Center, external auditory canal fractured forward. Note that the bone cut is performed just lateral to the tympanic membrane and the facial nerve. RIgM, remaining structures and defect after removal of surgical specimen.
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Figure 4. Lateral temporal bone resection type II. Left, outline of bone cuts in tympanic bone and potential extension through the neck of the condyle. Center, the tympanic bone with attached tympanic membrane, malleus, and Incus has been fractured forward. Right, remaining structures and surgical defect.
and extent of the tumor dictated the need to resect the entire tympanic bone, the stylomastoid foramen, and the facial nerve, as in the case of persistent or recurrent tumors following superficial parotidectomy, the bone cuts were performed in a plane medial to the fallopian canal, the stylomastoid foramen, and styloid process, which were included in the resected specimen. The jugular foramen and the internal carotid canal were the medial limit of the resection (Figure 5). T y p e IV lateral temporal bone resection: This type of resection was done when the tumor was adjacent only to the mastoid tip, the inferior aspect of the tympanic bone, or both. The external auditory canal lumen, the
tympanic membrane, and the middle ear structures were preserved while the inferior portion of the typanic bone and the mastoid tip were resected. Depending upon the clinical situation, the facial nerve and the styloid process could be resected or preserved (Figure 6). The resection of the lateral portion of the temporal bone was performed in conjunction with a parotidectomy, a partial mandibulectomy, a neck dissection, or a temporal craniectomy and resection of the glenoid fossa and the floor of the middle cranial fossa, depending upon the extent of the tumor. The resulting surgical defect was repaired with a temporalis muscle flap, a split-thickness skin graft, or both,
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Figure 5. Lateral temporal bone resection type III. Left, outline of bone cuts medial to the fallopian canal and potential extension through the neck of the condyle. Center, lateral portion of the temporal bone to be resected, including the styloid process, fallopian canal, and facial nerve, is fractured forward. Right, remaining structures and surgical defect.
Figure 6. Lateral temporal bone resection type IV. Left, outline of bone cuts through the mastoid tip and inferior portion of tympanic bone. Center, resected portion of the temporal bone displaced forward. Right, remaining structures and surgical defect.
whenever possible. Large defects, particularly those in which the dura or the internal carotid artery was exposed, were repaired with myocutaneous flaps. RESULTS The age of the 18 patients studied ranged from 43 to 89 years, with a mean age of 65 years. There were 16 men and 2 women. Histologically, the tumor was a squamous cell carcinoma in 11 patients, a basal cell carcinoma in 5, a poorly differentiated adenocarcinoma in 1, and a lymphoma in 1 patient. The latter was a patient with a lymphocytic lymphoma of the periauricular skin. Following treatment with chemotherapy and radiation therapy, he had a persistent painful ulceration that involved the skin
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and soft tissues of the pinna and the pre- and infraauricular skin. The tumor had not been previously treated in 7 patients, while 11 patients presented with either persistent or recurrent tumor after treatment outside of our institution. Previous treatment had consisted of surgery in six patients, radiation therapy in four patients, and combined surgery and postoperative radiation in one patient. A type I lateral temporal bone resection was performed in two patients. In one of these two, the tumor originated in the preauricular skin and had been previously treated with the Mohs' technique. The treating dermatologist was unable to obtain clear margins within the parotid. The resultant ulceration was adjacent to the osse-
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ous external auditory canal, but the skin of the canal was not involved. The other patient had a tumor that originated in the pinna and extended to within 1 cm of the external auditory canal, but the canal itself was univolved. A type II lateral temporal bone resection was performed in 10 patients. In five, the tumor originated in the skin of the external auditory canal. In three patients, the tumor arose from the preauricular skin and involved the underlying soft tissues, the parotid, and the external auditory canal. In one patient with a usual lymphoma, tumor and necrosis following chemotherapy and radiation widely involved the periauricular skin, the pinna, and the parotid. In one patient, the tumor orginated on the pinna; this was an exophytic, fungating lesion that did not appear to involve the skin of the external auditory canal, clinically or radiographically. Thus, a type I resection was performed, transsecting the tympanic bone and skin of the external auditory canal just lateral to the tympanic membrane. However, frozen section examination revealed tumor in the subepithelial plane at the resection margin near the tympanic membrane. Consequently, a type II resection was performed. A type III resection was performed in four patients. In one of these four, the tumor was a recurrent squamous cell carcinoma of the pinna that involved the external auditory canal, the preauricular skin, and the parotid. The remaining three patients had persistent or recurrent tumor in the parotid following a superficial parotidectomy done elsewhere. All of these patients had facial paralysis; in three patients, paralysis had developed as a result of the initial superficial parotidectomy. A type IV resection was done in two patients. One patient had a squamous cell carcinoma of the skin overlying the tip of the mastoid and the uppermost portion of the sternocleiodomastoid muscle. It had been previously treated unsuccessfully with the Mohs' technique. He then received radiation therapy (tumor dose 6,600 rad in 6 weeks), but the tumor persisted. A wide resection of the skin and the soft tissues of the area was performed in conjunction with a partial pinnectomy and a type IV lateral temporal bone resection in which the facial nerve and the external auditory canal lumen were preserved. The other patient had a superficial parotidectomy for a squamous cell carcinoma in the parotid. At the time of previous surgery, the tumor was found adjacent to the inferior aspect of the tympanic bone and surrounding the facial nerve at the level of the stylomastoid foramen; the patient was referred to us for definitive treatment. A total parotidectomy was performed in conjunction with a lateral temporal bone resection that included the mastoid tip, the inferior portion of the tympanic bone, the facial nerve, the stylomastoid foramen, and the styloid process. The temporal bone resection was performed in combination with a parotidectomy in 14 patients, a partial mandibulectomy in 4 patients, and a resection of the glenoid fossa and the floor of the middle cranial fossa in 2 patients. A cervical lymphadenectomy was done in 13 patients.
Postoperatively, one patient died of a cardiac arrhythmia. There were no other perioperative complications. The facial nerve was preserved in 13 patients. The inner ear was preserved in all patients; however, the type II and type III lateral temporal bone resections resulted in a pronounced ipsilateral conductive hearing loss. None of the patients developed vertigo. Seven patients received postoperative radiation. Follow-up ranged from 9 to 72 months, with a median of follow-up of 28 months. At last follow-up, 13 patients (72%) were alive and free of disease, 3 patients (17%) have died with distant metastases [2 of these 3 patients (11%) also had a local recurrence], and 1 patient (6%) is alive with distant metastases. COMMENTS It would appear from the results of this study that adequate surgical treatment of patients with selected advanced and recurrent malignant tumors of the external ear, the periauricular skin, and the parotid is possible with low morbidity and a high probability of local regional control when the diagnostic evaluation of these patients is performed in a systematic manner and the techniques of lateral temporal bone resection are used appropriately. Preservation of function is also maximized with this approach. The different lateral temporal bone resections performed in this study population have been categorized into four types. The type I resection consists of the removal of the tympanic bone and the external auditory canal lateral to the tympanic membrane. This type of lateral temporal bone resection has been referred to as a "sleeve resection" of the external auditory canal [6] and was briefly described by Jesse et al [7], who used it for the treatment of tumors that were localized to the external auditory canal and involved the bony portion of it. We would like to emphasize that "sleeve resection" does not, and should not, mean a resection of the skin of the external auditory canal alone. The type II resection consists of the removal of the entire tympanic bone, the tympanic membrane, the incus, and the malleus, preserving the facial nerve and the inner ear. Crabtree et al [4] described this type of resection as a means to perform a wide en-bloc resection of tumors of the external auditory canal that had invaded the bone of the external canal or mastoid, as long as the tumor extending into the mastoid "did not reach as deep as the mucosa of the middle ear or involve the facial nerve." The type III resection removes, in addition to the structures removed in the type II resection, the distal facial nerve and fallopian canal, the mastoid tip, the styloid process, and the stylomastoid foramen. Fisch and Mattox [5] refer to this technique as a total removal of the tympanic bone with subtotal petrosectomy, and they have described its use in the resection of tumors of the retromandibular fossa. The type IV resection consists of the removal of only the mastoid tip and the inferior portion of the tympanic bone. The external auditory canal, the tympanic mem-
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brane, and the middle ear are preserved. The facial nerve and the styloid process are removed when this technique is used for the treatment of tumors of the retromandibular fossa [5]; however, when resecting tumors of the retroauricular skin, a similar resection of the mastoid and tympanic bone can be performed without resecting the facial nerve or the styloid process. The decision to perform a lateral temporal bone resection and the decision as to what type of lateral temporal bone resection to perform is based upon the location of the tumor and the presence of tumor in certain critical areas of the temporal bone and surrounding structures, such as, the middle cranial fossa and the trigeminal ganglion, the middle ear and the aerated spaces of the mastoid, the medial portion of the external auditory canal, the facial nerve, the tympanic bone, and the temporomandibular joint. Unfortunately, it is not always possible to ascertain the presence or absence of tumor in these areas, even with a methodical preoperative assessment. Therefore, these operations must be performed in a systematic, step-by-step manner, verifying the presence and the extent of tumor in these critical areas. When intracranial spread of tumor is suggested by the preoperative evaluation, it may be advisable to begin the operation with a temporal craniotomy to assess the degree of intracranial involvement and to establish the resectability of the tumor. Intracranial spread of tumors about the ear can occur as a result of either direct extension through the floor of the middle cranial fossa or by perineural spread along the trigeminal nerve. In both instances, once the tumor reaches the dura, it can grow along the base of the skull with little resistance. Furthermore, if the trigeminal ganglion is found to be grossly involved by tumor, the prognosis is so poor that consideration should be given to discontinuing the procedure and using other forms of palliative therapy [8]. A lateral temporal bone resection should be discontinued if tumor is found in the middle ear or in the aerated spaces of the mastoid. Although in such cases, a radical mastoidectomy may accomplish a piece-meal resection of the tumor and may result in an occasional cure, particularly, when combined with postoperative radiation therapy [9], it is preferable to perform a subtotal resection of the temporal bone, if the condition of the patient permits it [2]. The circumferential margin of resection of the external auditory canal in a type I lateral temporal bone resection must be examined for the presence of tumor by frozen section. Tumors that involve the concha or the skin of the external auditory meatus can spread in the direction of the tympanic membrane in a subperichondrial-subperiosteal plane, underneath apparently normal skin and without deforming the external auditory canal. This phenomenon was observed in one of our patients. When this occurs, the tympanic annulus, tympanic membrane, and the malleus and incus are resected in a manner similar to a type II resection. The facial nerve was not resected in the patients in this study unless it was clinically and histologically involved
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by tumor. In patients in whom facial nerve involvement is obvious or suspected, the facial nerve must be exposed in its entirety in the mastoid. Note must be made of the macroscopic appearance of the nerve and a section of the margin must be submitted for examination by frozen section. The degree of involvement of the tympanic bone determines whether a type III or a type IV resection of the lateral portion of the temporal bone is necessary. When the tumor is only adjacent to the tip of the mastoid and the inferior portion of the tympanic bone, a type IV resection will provide an adequate margin of resection [5]. However, when tumor invasion of the tympanic bone is radiographically evident or it is discovered in the course of performing a type IV resection, the entire tympanic bone should be removed in conjunction with the tip of the mastoid, the facial nerve, and the styloid process (type III resection) [5]. Tumor involvement of the temporomandibular joint requires extending the lateral temporal bone resection to include the glenoid fossa, the mandibular condyle, and the floor of the middle cranial fossa [5]. It would appear that involvement of the temporomandibular joint by tumors about the ear is not common since it occurred in only two of our patients, both of whom had very extensive tumors. However, it must be emphasized that whenever tumor involvement of the joint was suspected in this series of patients, the lateral portion of the joint capsule was resected and examined by frozen section. This limited the indications for the more extensive resection of the base of the skull to those cases with histologically proven involvement of the temporomandibular joint. In sharp contrast with the perioperative morbidity associated with subtotal resection of the temporal bone, there were no perioperative complications related to lateral temporal bone resection in the patients reviewed in this study. Furthermore, since the inner ear was preserved in all patients, none of them exhibit postoperative vestibular dysfunction. Although this is a small series of patients, the low rate of local recurrence observed (11%) is noteworthy since most of these patients had either advanced, persistent, or recurrent tumors. In summary, the four types of lateral temporal bone resections described here can be used for the surgical treatment of selected malignant tumors of the ear, periauricular skin, and the parotid. Proper use of these techniques requires a methodical preoperative evaluation and a systematic intraoperative assessment of the extent of the tumor. The morbidity associated with the lateral temporal bone resections is low.
REFERENCES 1. Neely JG. Anatomic considerations of the medial cuts in the subtotal temporal bone resection. OtolaryngolHead Neck Surg 1982; 90: 641-5. 2. LewisJS, Parson H. Surgery for advancedear cancer.Ann Otol 1958; 67: 364-88. 3. Gacek RR, Goodman M. Management of malignancyof the
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temporal bone. Laryngoscope 1977; 87: 1622-34. 4. Crabtree JA, Britton BH, Pierce MK. Carcinoma of the external auditory canal. Laryngoscope 1976; 86: 405-15. 5. Fisch U, Mattox DE. Petrosectomy and facial rehabilitation in malignanttumors of the retromandibular fossa. In" Bull TR, Myers E, eds. Plastic reconstruction in the head and neck. London: Butterworths, 1986: 79-97. 6. Goodwin W J, Jesse RH. Malignant neoplasms of the external auditory canal and temporal bone. Arch Otolaryngol 1980; 106: 675-9.
7. Jesse RH, Healey JE Jr, Wiley DB. External auditory canal, middle ear, and mastoid. In: Maccomb WS, Fletcher GH, eds. Cancer of the head and neck. Baltimore: Williams & Wilkins, 1967: 412-27. 8. Mendenhall WM, Parsons JT, Mendenhall NP, Stringer SP, Cassissi N J, Million RR. Carcinoma of the skin of the head and neck with perineural spread. Head Neck Surg 1989; 11: 301-8. 9. Ward GE, Loch WE, Lawrence W Jr. Radical operation for carcinoma of the external auditory canal and middle ear. Am J Surg 1951; 82: 169-78.
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