Middle Fossa versus Retrosigmoid

[Kate B]

One of the things I learned in my fact finding stage, was that doctors do have a preference for a certain type of treatment--even when it comes down to surgery.  All doctors perform translab if they perform surgery. It is the oldest form of treatment. But when it comes down to a choice between middle fossa and retrosigmoid there exists individual preference.  If I can emphasize the importance of consulting with doctors that operate using both approaches.  They will have various opinions. I found that I learned something from each consult which ultimately helped me form a confident choice.  In other words, one is never certain of the outcome prior to surgery because these darn things are so individual. However, I felt going into my surgery, that after my consultations and reading, that I was making the best individual choice no matter the end result.  I had the confidence that I would get the best possible outcome for my tumor.  I could only do this after several consultations and article readings and website surfing. 

Here is cursory information about the two surgeries:

# Middle fossa

This approach will be used to attempt hearing preservation. Statistics show that the better the hearing one has ahead of the operation the better the chances of good hearing preservation. The location of the tumor on the superior nerve vs. the inferior nerve is better. The HEI website, www.hei.org, states that "In patients with small tumors who have been operated by the middle fossa approach since 1992., good hearing has been preserved in roughly two thirds of those patients. Any measurable level of hearing was preserved in 80%." It has higher hearing preservation rates for tumors under 2 cm than retrosigmoid. From the HEI website, it states that: "95% of 380 patients undergoing MF maintained excellent facial nerve function. Only five percent suffered minor weakness of facial nerve function."

The incision is made in front of the ear by creating a bone flap. There is an unobstructed view of the entire IAC with this surgical approach. This allows complete tumor removal. The middle fossa approach is performed by lifting of the temporal lobe of the brain. This approach is not recommended for patients above 60. At House Ear Institute, in a review of 500 cases with several years of follow-up, they identified only one case of residual tumor (0.2%).
# Retrosigmoid (suboccipital)

This approach is used to attempt hearing preservation. Success rates vary from 30-65% in CPA tumors smaller than 1.5 cm with good hearing and limited involvement of the IAC. However a tumor extending to the fundus is a contraindication to the RS approach for hearing preservation. The tumor removal is accomplished with mirrors.

Also reported is a "10% incidence of severe postoperative headaches" with this approach (Sliverstien et al, 1991) cited in Brackmann's paper.

Best of luck as you study your options,
Kate

[Russ]

Hi
  Actually, the sub-ociptital is the oldest form of surgery. Translab was refined by HEI. Copied from HEIs web site: "The management of acoustic neuromas has been revolutionized by the physicians and scientists at the House Clinic. In the early 1960's acoustic neuromas were treated utilizing a suboccipital approach without the aid of an operating microscope. At that time the mortality for acoustic neuroma removal in the State of California was 40%. At that time, Dr. William House, a young associate of his brother Howard, was able to diagnose a small acoustic neuroma. The patient was referred to a neurosurgeon and the neurosurgeon recommended that the tumor be observed - a common course of management at that time.
   The tumor grew relatively rapidly and was then operated by the suboccipital approach without the aid of magnification. Unfortunately, this young fireman died of the surgical procedure. This had a profound effect upon Dr. William House and at that time he began doing dissections in the laboratory with the aid of magnification and subsequently developed first the middle cranial fossa and then the translabyrinthine approach for removal of acoustic neuromas."

  I was told at Mayo Clinic the sub-occiptital has been the highest utilized surgical approach to ANs since removal attempts began in the early 1900s w/o the aid of the operating microscope.   -Russ

Kate wrote:  All doctors perform translab if they perform surgery. It is the oldest form of treatment.

Kate