Head and neck soft tissue necrosis

The incidence of soft tissue necrosis is very variable, according to the technique used. Pernot233, in a series of 1134 patients treated by external irradiation and/or brachytherapy, found 18 % of small superficial ulceration disappearing within two or three months, 4 % of persisting necrosis and 1 % or deep ulceration requiring usually surgery or repeated hospitalisation. The median duration of these soft tissues necrosis was respectively 3, 8 and 11 months.

Using external beam radiation therapy alone, the risk factors are stage, total dose, shorter treatment; hypofractionation is not a risk factor, unlike osteoradionecrosis234. Using external beam radiation therapy combined with brachytherapy, risk factors are total dose superior to 80 Gy, a surface treated superior to 12 cm2, a volume treated superior to 30 cm3 and a number of lines superior to 6 for Pernot233.

With brachytherapy alone, the risk factors are stage, total dose, a dose rate superior to 0.5 Gy/h (0.7 Gy/h for Pernot233), a large intersource spacing, a volume treated superior to 30 cm3 233>235>236. The tumour site is also a risk factor: floor of mouth is more often affected than mobile tongue236.

Current treatment of soft tissue necrosis includes local irrigation, wound debridement, antibiotics, analgesics and often prolonged observation. Surgery is rarely required. Pentoxifylline has been studied but its efficiency

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is not still confirmed237,238.

Some cases of successfully treated soft tissue necrosis with HBO have been reported239-242. Farmer240 reported two cases of nose and floor of the mouth necrosis, which were improved with HBO. Davis239 reported recovery in 15 out of 16 patients following HBO (2.4 ata, 90 min daily, 45 sessions in average) used as an adjunct to surgery and antibiotic treatment. Neovius242 published the results obtained in 15 patients treated with pre-operative radiotherapy. These patients presented with soft tissue necrosis, some of which also had fistula, free flap necrosis or chronic infections. Patients were treated with 30 or 40 sessions of 75 min, once or twice a day at 2.5 or 2.8 ata. Twelve of 15 patients healed completely, and 2 healed partially within 1-5 months after the introduction of HBO. However, only a few retrospective studies support the use of HBO for this indication, thereby leading to a poor level of efficacy evidence.

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