Requirement of the Preservation of Mental Nerve During the Transfer of Depressor Anguli Oris Composite Flap

Objectives: Reconstruction of wide lower lip defects is still a challenging subject in terms of obtaining functional and aesthetically acceptable results. Lower lip reconstruction with depressor anguli oris muscle was first described by Tobin in 1983. Since the sensory innervation of this composite muscle flap is provided by the mental nerve, it has been advocated that the mental nerve should be preserve during flap elevation. However, no further study has been conducted about this subject since then.
Methods: Sixteen patients with lower lip mass have undergone excisional biopsy. The resultant defects were higher than 30% of the total lower lip. All the defects were reconstructed with Depressor anguli oris composite flaps. In 9 of the patients, the mental nerve was preserved and included to the flap, while in remaining patients it was sacrificed. The results were evaluated in terms of sensation, function, and aesthetic appearance.
Results: In unilaterally reconstructed cases, the results regarding sensation and general complications were similar. However, in bilaterally reconstructed cases, especially where the mental nerve was preserved, the limited arc of rotation has resulted in functional complications, such as whistle deformity in the midline and drooling.
Conclusion: The mental nerve does not just limit the arc of rotation of the Depressör anguli oris composite flap but also remains as a potential route for metastasis via perineural invasion. Preservation and inclusion of the mental nerve during reconstruction with Depressor anguli oris flap do not provide any superior outcome; on the contrary, these results in various unfavorable events make this flap a poor option. The skin and mucosa of the DAO flap are innervated by the buccal branch of the trigeminal nerve; thus, the mental nerve should not be preserved during surgery.

Depressor anguli oris kompozit flebinin transferinde mental sinirin korunmasýnýn gerekliliði

Giriþ: Geniþ alt dudak defektlerinin kapatýlmasýnda iyi estetik ve fonksiyonel sonuçlar elde etmek için cerrahlarýn çabasý halen devam etmektedir. Depresör anguli oris kasý ile alt dudak rekonstrüksiyonu Tobin tarafýndan 1983 yýlýnda tanýmlanmýþtýr. Depresör anguli oris flebinin kompozit flebi duyusunun mental sinir tarafýndan taþýndýðý bu nedenle hazýrlanmasý esnasýnda mental sinirin korunmasý gerektiði savunulmuþ ve bu sav üzerine daha sonra yeterli araþtýrma yapýlmamýþtýr.
Materyal Metod: Kliniðimize alt dudakta kitle þikayeti ile baþvuran ve kitle eksizyonu sonrasýnda %30 un üzerinde defekti olan 16 hastanýn 9 unda mental sinir korunarak, 7 sinde mental sinir korunmaksýzýn DAO fleple rekonstrüksiyon yaparak duyu, fonksiyon ve estetik açýdan sonuçlarý deðerlendirdik.
Bulgular: Tek taraflý flep uygulanan vakalarda duyu ve genel komplikasyonlar açýsýndan sonuçlar benzer olup özellikle çift taraflý flep uygulanan; mental sinirin korunduðu hastalarda flebin rotasyon arkýnýn yetmezliði nedeniyle alt dudak orta hatta whistle deformitesi yada drooling tarzý komplikasyonlar oluþabilmektedir.
Sonuç: Depresör anguli oris kasýnýn defekte rotasyonunu kýsýtlayan, rotasyon kýsýtlamasý nedeniyle ýslýk deformitesi oluþmasýna neden olan, karsinomlarda perinoral yayýlma yoluyla kraniyal metastaz yolu olan mental sinirin; flep hazýrlanmasý esnasýnda korunmasý hiçbir avantaj katmamakla birlikte birçok olumsuz duruma neden olmakta ve bu flebin nerdeyse unutulmasýna neden olmaktadýr. Flep içeriðindeki cilt ve mukozanýn duyusu trigeminal sinirin bukkal dalý tarafýndan taþýnmaktadýr ve cerrahi esnasýnda mental sinirin korunmasýna gerek yoktur.