Introduction: Trautmann's triangle is defined as the area limited by the anterior border of the
sigmoid sinus posteriorly, the petrous ridge superiorly, and a line connecting the
jugular bulb to the petrous apex anteriorly. Its size is important for transpetrosal
approaches and variants. We studied Trautmann's triangle anatomy and its area in transpetrosal
approaches.
Methods: Five cadaveric heads (10 sides) were submitted to transpetrosal approaches and its
variants: retrolabyrinthine, partial labyrinthectomy, translabyrinthine, transcochlear,
and total petrosectomy. At each step the following measurements were taken: (1) area
of the Trautmann's triangle; (2) sinodural angle to jugular bulb (SA-JB); (3) sinodural
angle to otic capsule (SA-OC); and (4) otic capsule to jugular bulb (OC-JB).
Results: Progressive drilling of the otic capsule for each of the transpetrosal approaches
increased the area of the triangle. The exposure of the structures of the posterior
fossa was increased significantly after the partial labyrinthectomy, but not after
the next steps. The average distances were: (1) SA-JB, 26.5mm (± 3.3 mm SD); (2) SA-OC,
18 mm (± 2.3 mm SD); and (3) OC-JB, 18.4 mm (± 1.7 mm SD).
Conclusion: Trautmann's triangle is of greatest importance in the performance of the lateral
transtemporal approaches. Its size determines the working area and angle of attack
to the posterior fossa.
