Osteoplastic mastoidectomy followed by single-flap temporo-suboccipital craniotomy: combined supra- and infratentorial approach

The combined supra- and infratentorial transpetrosal approach requires a su btemporal-suboccipital craniotomy and a mastoidectomy to unroof the dural s inuses. We describe a modified surgical technique that reduces the bone def ect in the mastoid area and decreases the risk of violating the dural sinus es. Before the craniotomy, a surface mastoidotomy - the removal of the oute r layer of the mastoid process - is carried out using a drill and a chisel for later reconstruction of the mastoid process. This is followed by a deep mastoidectomy in conjunction with petrosectomy to unroof the sigmoid sinus . Through a cavity made by the mastoidectomy, the lateral sinus is dissecte d from its bony groove. A single flap temporo-suboccipital craniotomy is pe rformed necessitating few burr holes or none. Upon closure the temporo-occi pital bone flap and mastoid flap are fixed together. The surface mastoidoto my followed by single-flap temporo-occipital craniotomy minimizes the bone defect in the mastoid area. In addition, beginning such a procedure with a mastoidectomy facilitates safe dissection of the outer dura covering the si nuses and adherent to the bony groove.