Chapters Transcript Translabyrinthine approach for vestibular schwannoma Mayo Clinic otolaryngologistMatthew L. Carlson, M.D. demonstrates a translabyrinthine approach for vestibular schwannoma. Matthew L. Carlson, M.D. This surgical instructional video outlines the indications and surgical steps of the trans labyrinthine approach for vestibular Phoma resection. The trans labyrinthine approach is a versatile surgical approach to access the cerebellopontine angle and internal auditory canal. It provides the shortest working distance to the cerebellopontine angle and the internal auditory canal and does not require any brain retraction for access of tumor. It can be used for any tumor size in a patient with non serviceable hearing or in cases with a larger tumor size where preservation of functional hearing is unlikely. This is a right ear incision is marked approximately 5 to 6 centimeters behind the troy canal to allow adequate access to the mastoid for optimal surgical exposure. The incision is carried through skin and subcutaneous tissue and staggered slightly forward in the subperiosteal plane. Well, this is based on surgeon preference. I like to grab a small piece of temporalis fascia to use later in order to block the mastoid Antrim to reduce the risk of postoperative CS F leak. As you can see, a small piece of temporalis fascia is being harvested next using electro coy. A staggered incision is made through the muscular periosteum to the mastoid cortex. The sterno clio mastoid insertion at the mastoid tip is rather adherent and electro pottery is often required to elevate the sub periosteum. After the insertion of the steroidal mastoid muscle is removed, the soft tissue elevates much more freely. And this can be performed with the subperiosteal elevator. The flap should be raised in the subperiosteal plain until the ear canal is encountered. A wet rack is then placed and finally, fish hooks are used to retract the muscular cutaneous flap forward. Next, a small cuff of mussels obtained it will be used later to obliterate the middle of your space again to reduce the risk of postoperative CS F leak. Next. A wide cortical mastoidectomy with antrotomy is performed using the largest cutting, a drill bit possible with continuous irrigation bone should be decompressed lateral to the temporal dura and posture to sigma sinus. In order to gain adequate surgical exposure. Here, you can see the lateral semi circular canal and in a minute, you will see the short process of the incus both important landmarks for identifying the facial nerve. After thinning the bone over the temporal dura, the thin layer of bone is decompressed to expose the temporal dura. This improves surgical exposure, improved hand working area and illumination of the surgical field in a similar way. Bone over the sigmoid sinus is thinned and finally the thin layer of bone is removed with a freer. It's important to perform this carefully in order to reduce your risk of accidental venotomy in significant bleeding and significant bleeding is encountered from the sigmoid sinus placement of gel foam, gentle pressure in some patients will stop virtually any sigmoid sinus bleed bone in the sural angle is then removed. The super petrosal sinus runs along this groove and care should be taken to avoid injuring this. Next, a lainy is performed. This is generally first started by drilling the bone over the lateral semi circular canal. In order to protect the facial nerve. At the second genu, the surgeon should not drill inferior to the inferior aspect of the lateral semi circular canal, leaving this wallop as a buffer reduces your risk of inadvertent facial nerve injury. During Laroy, after drilling the lateral semis sugar canal, the surgeon can drill more posterior where they will encounter the posterior semi circular canal. And finally, the superior semi circular canal is located superior to both of these canals and in the deeper plain, the posterior semi circuit canal and the superior semi circular canal meet at the common cruise. Additionally, an artery can always be seen coursing through the Subaru canal. This is another reliable landmark for the superior semi circular canal. The confluence of the semi circular canals is at the vestibule located essentially just deep to the second genu of the facial nerve. When drilling near the vestibule. It's very important to not undercut and accidentally injured the facial nerve as it courses through the tipa segment. Here you can see the vestibule located just deep to the second genu of the facial nerve. The opening at the terminal end of the superior vestibular nerve can be seen in the vestibule. This is called Mike's dot The floor of the vestibule marks the lateral extent of the internal artery canal. At the fungus. The cochlear aqueduct can be encountered between the labyrinth and the jugular bulb in small or medium sized tumors, the cochlear aqueduct is often patent and by opening it egresses CS F can be achieved which helps relaxation of the brain. Next, the internal auditory canal is identified. It's important to realize that the lateral most extent of the internal artery canal is much closer to the surgeon than the medial extent at the porus. After the internal canal is identified, superior and inferior troughs are performed such that at least 100 and 80 but more preferably closer to 270 degrees at the inter andre canal is decompressed. Why decompression is particularly important for large tumors that extend anterior to the poorest acoustics. The thinned bone over the intern oy canal is finally removed, exposing the dura of the internal Aroy canal, the metal segment of the facial nerve most commonly courses in an anti superior location. Therefore, drilling on the superior trough, particularly near the fungus must be performed very carefully to avoid injury to the facial nerve. Next, the posture faur is bipolar coagulated and opened. It's important to avoid arterial or venous injury when entering the dura, particularly if CS F could not be re released earlier from the cochlear aqueduct. Next, the dorsal portion of the tumor in the cerebellopontine angle is stimulated with ARAS probe. After confirming that the facial nerve is not in the unusual location of the dorsal pole of the tumor. The tumor is bipolar coagulated, the capsule is incised and the tumor is internally debulked. After the tumor is internally debulked, the capsule wall can be folded into the surgical field for removal. After the poster foci component of the tumor is removed. The portion of tumor in the internal oy canal can be removed again. The facial nerve is most commonly located in the anterior superior location within the internal otra canal and great care should be taken to avoid injury to the nerve in this location. Here, you can see the tumor is being carefully dissected from the superior vascular nerve as well as the facial nerve. The superior vascular nerve can be cut early in the course of dissection or some surgeons prefer to maintain its continuity during dissection as it provides some additional support to the facial nerve and reduces the risk of stretch injury. The facial nerve can be seen just deep to the superiority of their nerve. Here. The remainder of the tumor is then removed. After hemostasis of the posture Phosa is obtained, the middle ear is packed with muscle and fascia to reduce the risk of CS F leak. Some surgeons prefer to perform a facial recess with or without removal of the incus to directly visualize the eus station tube for obliteration. While others indirectly obliterate this area through packing of the middle ear space through the antrum. According to surgeon preference, an artificial dural substitute can be placed to reconstitute the posture Faid dura fat is then placed in the mastoid defect. The previously harvested fascia is then used to block the mastoid Antrim and finally, additional fat is used to fill the remaining portion of the mastoid cavity. Bone wax can be used to obliterate any open mastoid air cells based upon surgeon preference and absorbable mesh or titanium mesh cranioplasty can then be performed to secure the mastoid fat in place and reduce the risk of pseudomonal or CS F leak. The incision is then closed in anatomical layers and a head wrap is applied. This concludes the surgical instructional video on trans labyrinthine approach for stoma resection. Published March 12, 2018 Created by Related Presenters Matthew Carlson, MD Otolaryngologist Otolaryngology (ENT)/Head and Neck Surgery View full profile
