Discomalleolar and anterior malleolar ligaments: possible causes of middle ear damage during temporomandibular joint surgery.

Damage to structures within the middle ear during surgical manipulation of the temporomandibular joint (TMJ) has been reported. Two structures are proposed as possible intermediaries in this trauma: the discomalleolar ligament (DML), which passes from the malleus to the medial retrodiscal tissue of the TMJ, and the anterior malleolar ligament (AML), which connects the malleus with the lingula of the mandible via the sphenomandibular ligament (SML). It has been hypothesized that when tension is applied to the DML and/or AML, the resulting movement of the malleus could cause damage to the tympanic membrane and associated structures. The objective of this study was to determine whether tension applied to the DML and/or the AML could cause movement of the malleus. With the use of a superior medial approach through the middle cranial fossa, the ligaments connecting the malleus with the mandible were examined in 52 adult/human cadaveric half-heads. Tension applied directly to the SML resulted in movement of the malleus in three specimens. Similar tension applied to the DML did not cause movement of the malleus. Histologic evidence showed a continuity of fibers between the SML and AML. When the mandibular condyle was distracted inferiorly, tension was demonstrated in the SML. The results indicate that the AML via the SML has the potential to cause middle ear damage and is more likely to do so than the DML.