Microvascular reconstruction of the tongue using a free anterolateral thigh flap: Three-dimensional evaluation of volume loss after radiotherapy

The goal of tongue microvascular reconstruction is to maximise oral function with less morbidity while preserving speech and swallowing. This kind of reconstruction often requires a bigger flap volume than is actually needed to repair the defect. This is because every reconstructive flap is subject to a shrinking process due to oedema reduction and differences among individual tissue healing processes. Moreover, patients with advanced cancers often need adjuvant radiation therapy, which can result in further flap volume loss. For these reasons, we designed this study to assess the three-dimensional flap volume loss after tongue reconstruction using an anterolateral thigh flap (ALTF). Our aim was to analyse the effects of radiotherapy on flap volume loss. The volume of ALTF was evaluated using the following protocol: an initial (T1) post operative magnetic resonance imaging (MRI) scan was acquired between 3 and 8 weeks after the reconstructive procedure; a second (T2) MRI scan was obtained 6 months later; and a third (T3) MRI scan was performed 1 year after the end of treatment. Three-dimensional flap contouring was carried out, with outlining of the graft margin and comparison of its tissue density with that of the surrounding structures. Flap volume was calculated using dedicated software. In total, 20 patients who satisfied the inclusion criteria were enrolled. Adjuvant radiation therapy was administered in 11 of the 20 patients. In the patients treated with postoperative radiotherapy, the mean flap volume loss was 16.5 cm3. The patients who were not irradiated postoperatively showed a mean flap volume loss of 6.9 cm3; this difference was statistically significant (p = 0.041). Our study indicated that 12 months after the end of treatment, patients reconstructed with an anterolateral thigh free flap had an average volume loss of 44.2% if treated with radiotherapy, whereas an average flap shrinkage of 19.8% occurred in patients who did not undergo postoperative radiotherapy. For these reasons, we recommend overcorrection by a factor of 1.4 in radiotherapy-treated patients, while a correction factor of 1.2 should be sufficient in patients not undergoing adjuvant radiotherapy.