Otology Semina
Osteoradionecrosis of the temporal bone
2004-9-8
R3 林正民
Background
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Osteoradionecrosis(ORN) first described by Ewing in 1926.
 Radiation damage to temporal bone serous otitis media, SNHL, soft
tissue breakdown, and osteonecrosis.
First case of ORN with osteomyelitis in temporal bone. (Block, 1952)
Aggravating factor: concurrent local infection, especially chronic otorrhea
susceptible to secondary mastoiditis. (Schuknecht, 1966)
Ramsden et al(1975): 29 cases of temporal bone ORN
 All conservative follow-up: natural extrusion of sequestered bone and
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resolution of the local infection would take 1 to 4 years.
9 cases had diffuse ORN with significant complications, including
labyrinthitis, facial nerve paralysis, intracranial suppuration.
Temporal bone necrosis: most localized in tympanic bone.
Pathophysiology and Classifications
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Petrous bone/cochlea: ＞ 50 % of total RT dose for NPC, LAP in level II & Va.
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Effect of radiation vasculitis, mitotic inhibition subsequent aseptic,
avascular necrosis of bone and soft tissue, lacking osteoblastic activity repair
with fibrosis susceptible to trauma, infection.
Radiation to the soft tissue: dermatitis of EAC, inflammation of middle ear
mucosa, otitis media, and aseptic labyrinthitis.
In addition to temporal bone ORN, ORN of ossicular chain after RT had been
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reported, especially in lenticular process of incus. (Kveton JF, 1986)
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Temporal bone necrosis unrelated to radiation: benign necrotizing otitis externa.
 Cause: unknown. Maybe due to repeated trauma, DM, vascular abnormally.
Assessment
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Exposure of radiation or idiopathic.
The average time between radiation exposure and presentation: 8.4 years (range,
<1 to 23 yr)
Symptoms/signs
 Most common: Deep boring otalgia, profound otorrhea, hearing loss.
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Hearing loss can be conducitve, sensorineurla, or mixed.
Examination
 Radiation otitis media: sterile exudates in middle ear—most common after
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temporal bone irradiation, but not indication of ORN.
Most common findings in temporal bone ORN—purulent otorrhea.
Bone exposure in EAC with bony sequestrum, usually on floor.
Others: facial palsy, CSF otorrhea, meningitis, TMJ involvement, SNHL,
sometimes even dural dehiscences.
Always take recurrence into consideration!
Radiology
 Best imaging study: temporal bone CT scan with intravenous constrast.
 Bony destruction, or neoplasm, abscess, or lateral sinus thrombosis
1/3 in diffuse temporal bone ORN: intracranial infection. (Ramsden, 1975)
 MRI scan: more specific for intracranial involvment, especially while
neurological deficits present.
Management: medical
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Initial therapy for controlling otorrhea & acute infection
aural toilet, ototopic antibiotics, repeated local debridement, and
culture-directed use of systemic antibiotics.
Ramsden et al: natural extrusion of sequestered bone and resolution of the
local infection may take 4 years.
Pathak et al: medical therapy only for young patients with localized disease.
Management: surgical
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Surgical debridement & resection of necrotic bone for diffuse ORN
Goal: remove all necrotic tissue
Extensive surgery: radical mastoidectomy, lateral temporal bone resections,
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petrosectomy, resection of extratemporal tissues
Revision surgery: ＞ 50%
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Intraoperative fluorescence: 7-10 days of tetracycline before surgery
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increased Ca labeling to detect viable bone.
Soft tissue coverage of viable bone after debridement, ex: adipose tissue.
revasvularization of local tissue.
Modified parotid incision: Blind sac closure of EAC, preservation of soft
tissue blood supply
Other tissue coverage: skin graft, local flap (ex temporoparietal, temporalis
muscle flap), regional flaps (ex pectoralis, latissimus m.) and free flap.
Management: role of hyperbaric oxygen
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Hyperbaric oxygen (HBO): intermittent, inhalation of 100% oxygen at a
pressure greater than one atmosphere absolute.
 Increasing oxygen dose dissolved in plasma & delivered to tissues.
 Stimulating angiogenesis in the hypovascular tissue.
HBO for
Mandibular ORN: good response
Temporal bone ORN: controversial
At present, HBO for localized ORN of temporal bone or combined with
surgery or medicine for diffuse disease
Reference
1. Schuknecht HF, Karmody CS. Radionecrosis of the temporal bone. Laryngoscope.
1966;76(8):1416-28.
2. Ramsden RT, Bulman CH, Lorigan BP. Osteoradionecrosis of the temporal bone. J
Laryngol Otol. 1975;89(9):941-55.
3. Kveton JF, Sotelo-Avila C. Osteoradionecrosis of the ossicular chain. Am J Otol.
1986;7(6):446-8.
4. Ondrey FG, Greig JR, Herscher L. Radiation dose to otologic structures during
head and neck cancer radiation therapy. Laryngoscope. 2000;110(2 Pt 1):217-21.
5. Perez CA. Principle and practice of radiation oncology, 4th ed.
6. Pathak I, Bryce G. Temporal bone necrosis: diagnosis, classification, and
management. Otolaryngol Head Neck Surg. 2000;123(3):252-7.
7. Ma KH, Fagan PA. Osteoradionecrosis of the temporal bone: a surgical technique
of treatment.Laryngoscope. 1988;98(5):554-6.
8. Vudiniabola S, Pirone C, Williamson J, Goss AN. Hyperbaric oxygen in the
therapeutic management of osteoradionecrosis of the facial bones. Int J Oral
Maxillofac Surg. 2000;29(6):435-8.