下顎第三大臼歯抜歯における舌神経損傷の頻度：2つの手術手技の比較

FREQUENCY OF LINGUAL NERVE INJURY IN MANDIBULAR THIRD MOLAR EXTRACTION: A COMPARISON OF TWO SURGICAL TECHNIQUES.

抄録

背景:

下顎第三大臼歯の外科的抜歯は、術後出血、ドライソケット、術後感染、局所神経損傷などの多くの合併症を伴う。舌神経損傷は主な合併症の一つである。この合併症を予防するために、これまで様々な手法が用いられてきました。Lingual flap reflectionはその一つで、舌側軟組織を反射させて意図的に後退させ、神経を識別して術野に入れないようにする方法である。本研究の目的は、舌神経損傷の頻度を最小限に抑えた第三大臼歯抜去術の術式を評価することである。

BACKGROUND: Surgical removal of impacted mandibular third molar is associated with a number of complications including postoperative bleeding, dry socket, postoperative infection, and injury to regional nerves. Lingual nerve damage is one of the main complications. To prevent this complication different techniques had been used. Lingual flap reflection is one of these procedures in which lingual soft tissue is reflected and retracted deliberately, the nerve is identified and is kept out of the surgical field. The objective of this study was to evaluate a surgical technique for third molar removal which is associated with minimum frequency of lingual nerve damage.

方法:

無作為化比較試験を実施した。下顎第三大臼歯に衝撃を受けた患者380名を本研究に組み入れた。各患者はブロック無作為化法により、頬側フラップに加えて舌側フラップの反射と後退を行うA群と、頬側フラップのみの後退を行うB群に無作為に割り振られた。

METHODS: A randomized controlled trial was performed. A total of 380 patients with impacted mandibular third molars were included in this study. Each patient was allotted randomly by blocked randomization to group A where procedure was performed by reflection and retraction of lingual flap in addition to buccal flap and group B where procedure was performed by retraction of buccal flap only.

結果:

舌神経の損傷は、舌側フラップの後退を行ったA群では8.94％に認められましたが、損傷は可逆的でした。B群では、2.63％の舌神経損傷が認められ、損傷の性質は永久的であった。この差は統計学的に有意であった（p=0.008）。

RESULTS: Lingual nerve damage occurred in 8.94% in Group A in which lingual flap retraction was performed but damage was reversible. In group B, 2.63% lingual nerve damage was observed and nature of damage was permanent. The difference was statistically significant (p=0.008).

結論:

下顎第三大臼歯の抜歯時に舌小帯を後退させると、舌神経損傷のリスクが3.4倍上昇するが、損傷の性質は可逆的である。

CONCLUSIONS: Lingual flap retraction poses 3.4 times increased risk of lingual nerve damage during extraction of mandibular third molar when lingual flap is retracted but the nature of damage is reversible.