This video demonstrates the operative setup and surgical steps of a middle fossa approach for the resection of vestibular schwannoma (acoustic neuroma).
Authors:
Cameron C. Wick, MD (cameron.wick@wustl.edu) 1
Samuel L. Barnett, MD (sam.barnett@utsouthwestern.edu) 2
J. Walter Kutz Jr., MD (walter.kutz@utsouthwestern.edu) 3
1 – Department of Otolaryngology – Head and Neck Surgery, Washington University School of Medicine, St. Louis, MO
2 – Department of Neurosurgery, University of Texas Southwestern Medical Center, Dallas, TX
3- Department of Otolaryngology – Head and Neck Surgery, University of Texas Southwestern Medical Center, Dallas, TX
Middle Fossa Approach for Vestibular Schwannoma (Acoustic Neuroma) Resection
Hearing preservation approach for small tumors (< 15 mm)
Patient preference with reasonable expectations
Medium to large tumors with extension into the cerebellopontine angle (CPA)
No Hearing
Relative Contraindications: age > 65 years, no fundal cap (tumor abuts the cochlea in the lateral internal auditory canal), poor hearing (pure-tone average worse than 50 dB or speech discrimination worse than 70%), seizure disorder
Operative surgeon is at the head of the bed. Patient is in the supine position with head rotated so the operative ear is facing up.
Intraoperative monitoring of cranial nerves 7 and 8.
MRI with and without gadolinium
Audiogram
Anatomy Pearls
- Create large craniotomy (5 cm x 5 cm)
- Arcuate eminence only predicts the superior semicircular canal 50% of the time, therefore we advocate blue-lining the canal to create a definitive landmark
- Geniculate ganglion is dehiscent 5 - 15% of the time, therefore elevate dura in posterior to anterior direction
- There are multiple ways to identify the internal auditory canal (IAC). After blue-lining the superior semicircular canal, we advocate for finding the IAC medially at the porus because there is more room to dissect. Other approaches include:
1. House (1961) —> Retrograde dissection from the GSPN to the labyrinthine segment of facial nerve
2. Fisch (1970) —> Dissect in a 60-degree angle from a blue-lined semicircular canal
3. Garcia-Ibanez (1972) —> IAC bisects the angle formed between the superior semicircular canal and the GSPN
- Medial IAC dissection allows 270-degrees of exposure while the lateral IAC dissection only allows 90-degrees
- After exposing the porus, release CSF from the posterior fossa to relax the dura and possible allow withdrawal of the retractor
- Try to dissect tumor in a lateral to medial direction to prevent cochlear nerve avulsion from the lamina cribrosa
Advantages:
- Provides complete exposure of the IAC and possibly allows tumor resection with hearing preservation
Disadvantages:
- Technically challenging because of the limited exposure and often nebulous surgical landmarks along the floor of the middle fossa
- Facial nerve is positioned between the dissection approach and the tumor, therefore potentially higher rates of facial nerve weakness.
- Requires retraction of the temporal lobe.
CSF leak (2-7%), facial nerve weakness/paralysis (15% immediate, 5% long-term), hearing loss (outcomes dependent on tumor size, location, nerve of origin, and pre-operative hearing), seizure, stroke, meningitis, death
None
None
1. Kartush JM, Kemink JL, Graham MD. The arcuate eminence: Topographic orientation in middle cranial fossa surgery. Ann Otol Rhinol Laryngol. 1985;94:25-28.
2. Isaacson B, Vrabec JT. The radiographic prevalence of geniculate ganglion dehiscence in normal and congenitally thin temporal bones. Otol Neurotol. 2007;28:107-110.
3. Wade PJ, House W. Hearing preservation in patients with acoustic neuromas via the middle fossa approach. Otolaryngol Head Neck Surg. 1984;92:184-193.
4. Gantz BJ, Parnes LS, Harker LA, et al. Middle cranial fossa acoustic neuroma excision: results and complications. Ann Otol Rhinol Laryngol. 1986;95:454-459.
5. Shelton C, Brackmann DE, House WF, Hitselberger WE Middle fossa acoustic tumor surgery: Results in 106 cases. Laryngoscope. 1989;99:405-408.
6. Shelton C, Brackmann DE, House WF, Hitselberger WE. Acoustic tumor surgery. Prognostic factors in hearing conservation. Arch Otolaryngol Head Neck Surg. 1989;115:1213-1216.
7. Dubrulle F, Ernst O., Vincent C., et al. Cochlear fossa enhancement at MR evaluation of vestibular schwannoma: Correlation with success at hearing-preservation surgery. Radiology. 2000;215:458-462.
8. Meyer TA, Canty PA, Wilkinson EP, Hansen MR, Rubinstein JT, Gantz BJ. Small acoustic neuromas: surgical outcomes versus observation or radiation. Otol Neurotol. 2006;27:380-392.
9. Kutz JW Jr, Scoresby T, Isaacson B, et al. Hearing preservation using the middle fossa approach for the treatment of vestibular schwannoma. Neurosurgery. 2012;70:334-340.
10. Friedman RA, Kesser B, Brackmann DE, Fisher LM, Slattery WH, Hitselberger WE. Long-term hearing preservation after middle fossa removal of vestibular schwannoma. Otolaryngol Head Neck Surg. 2003;129:660-665.
11. Woodson EA, Dempewolf RD, Gubbels SP, et al. Long-term hearing preservation after microsurgical excision of vestibular schwannoma. Otol Neurotol. 2010;31:1144-1152.
12. Quist TS, Givens DJ, Gurgel RK, et al. Hearing preservation after middle fossa vestibular schwannoma removal: are the results durable? Otolaryngol Head Neck Surg. 2015;152:706-711.
This video shows a transotic approach for a cochlear schwannoma in a 59-year-old female who presented with sudden sensorineural hearing loss in her left three years prior. She was found to have subsequent growth of her tumor on imaging and elected to undergo surgery. The transotic approach is a valuable approach within the armamentarium of a skull base team and differs from the transcochlear approach in the handling of the facial nerve. Techniques for ear canal overclosure, eustachian tube packing and mastoid obliteration are also highlighted.
Here, we have a 39 yrs old female with complaints of noisy breathing for last two years post thyroidectomy. Flexible laryngoscopy confirmed bilateral vocal cord paralysis. She was planned for coblation assisted cordectomy.
Patient was taken up for procedure under general anaesthesia. She also started having stridor after induction. Nasopharyngeal intubation with spontaneous breathing technique was used. Entropy leads were placed over forehead to monitor the depth of anaesthesia. Tube position was confirmed with endoscopic view and Benjamin lindohlm laryngoscope was suspended. As the patient was spontaneously breathing, the stridor became more prominent, with stable vitals and the procedure was continued. The vocal cord retractor was fixed and coblation wand was then used with 7:3 settings for ablation and coagulation respectively. The surgical limits were-anteriorly the junction between ant 2/3 and post 1/3 of the vocal cord, posteriorly just anterior to the vocal process of arytenoid to prevent cartilage exposure and post operative granulations. Superely till the ventricle and inferioly till the medial most surface of the subglottis. Laterally approx. 5 mm depth was defined to prevent injury to the superior laryngeal artery branch and further bleeding. Once the final airway was achieved , the topical lignocaine was used to prevent laryngeal spasm post extubation.
The patient was shifted to the ward without oxygen, the voice was assessed on post op day 2.
Patient was called for follow up on post op day 14th and good voice outcomes were achieved.
So lets have a look on some tips & tricks for the safe procedure—–
Nasopharyngeal insufflation technique with entropy monitor will give adequate and safe surgical field
2. Appropriate exposure will help you to delineate the surgical margins
3. Topical anaesthesia before and after the procedure will prevent sudden laryngeal spasm
4. Firm holding of coblation device will help to prevent injury to surrounding structures like anterior 2/3 vocal cord, opposite side vocal cord, medial surface of vocal cord or aryteroid posteriorly
5. Do not ablate more laterally to prevent bleeding, if at all it happens, use patties or coagulation switch for hemostasis.
6. And at the end of the procedure ,use catheter suction to suck out blood clots or saline from the airway if any….
To Conclude-Coblation Assisted Cordectomy( CAC) can be performed safely with good outcomes in case of bilateral vocal cord paralysis using tubeless anesthesia technique without tracheostomy !
We present the harvest of a osteocutaneous fibula free flap for head and neck reconstruction performed at the University of Cincinnati. This reconstructive technique has a wide variety of implications but has found greatest utility in the reconstruction of mandibular defects.
Review Middle Fossa Approach for Vestibular Schwannoma (Acoustic Neuroma) Resection.