Ravi Gandhi, MD, a Neurosurgeon who focuses on Neurovascular Diseases and Skull Base Tumors talks about Vestibular Schwannoma.
Interview conducted by Ivanhoe Broadcast News in March 2018.
I want to ask you a little bit about Acoustic Neuroma. Can you explain what it is?
Dr. Gandhi: Vestibular Schwannoma is more appropriate, and the reason is that it’s a type two tumor that grows off of the vestibular nerve most commonly. It also grows from the Schwann cells. The Schwann cells are a type of cell that coats the nerves, the nerves are basically wires and so the electrical part is the nerve and then the Schwann cells create a coating on top of that nerve.
When you hear Schwannoma is that something that’s cancerous?
Dr. Gandhi: No, they’re usually benign tumors, there is a very rare risk of malignant conversion. But most of the time they are benign tumors.
Which is the good news for patients.
Dr. Gandhi: Yes.
Tell me a little bit about the symptoms, how would a patient know that this is potentially a problem?
Dr. Gandhi: Sure. Anything in the brain is always based on location. The Vestibular Schwannomas grow behind the ear just inside the skull. And the symptoms come from the nerves that are in that location. There are three nerves, the Vestibular nerves which control our balance, the cochlear nerve which controls our hearing and then the facial nerve which obviously controls our facial movement. The most common symptoms that patients present with are unilateral hearing loss. Most of the time these tumors are unilateral, they can sometimes be bilateral or on both sides in syndrome called Neurofibromatosis type two. But most them are sporadic and are unilateral in which case patients most commonly present with gradual or sometimes sudden hearing loss. The other symptoms that are more common are tinnitus which is ringing in the ear, sometimes balance difficulties and then more rarely facial weakness. Or sometimes face pain which are other less common symptoms.
When you’re talking about symptoms like facial weakness, could that suggest to a patient or his or her family members as something else potentially?
Dr. Gandhi: Not commonly it can sometimes be misdiagnosed perhaps if somebody were to present with facial weakness as a Bells Palsy. But the most common symptom is hearing loss and patients may just kind of write it off that their hearing loss is you know old age or something like that. Obviously when it happens to younger patients they’re more suspicious and more worried.
When you have these symptoms what does a patient do, how do they go about getting a diagnosis?
Dr. Gandhi: The best way to diagnose a Vestibular Schwannoma is a MRI with contrast which is the most sensitive test. Often before that patients will get an audiogram which will demonstrate a difference in their hearing threshold between the two sides. That will prompt an MRI which will reveal the diagnosis.
We had talked to one patient who is going through a series of it seemed almost like vision, balance, hearing tests. Can you talk a little bit about a testing process?
Dr. Gandhi: I think what you’re referring to is probably a VNG and that’s really looking for a patient’s vestibular response. That also may lead to the diagnosis of an acoustic or vestibular Schwannoma. More commonly it ends up doing a test that we do after we discover that somebody has a vestibular Schwannoma to assess some of their function before surgery to help in planning for surgery.
What are the therapists looking for and what does the doctor do with that information from the test?
Dr. Gandhi: It helps sometimes to give us an indication as to where amongst this bundle of nerves the tumor is perhaps growing from. It gives us some indication as to what the postoperative, if surgery ends up being the treatment choice, what the postoperative outcome may be. That’s where that information helps us in sort of planning and counseling.
You had mentioned a VNG and I believe that was what it was. What does that stand for?
Dr. Gandhi: I think it’s called a vestibular nystagmogram, I’m not a hundred percent sure on that one.
From that information then what can surgeons do?
Dr. Gandhi: Once a vestibular trinoma is discovered there’s essentially three options. Each of these options depend on the size, location, symptoms of the tumor in the patient. Specific things such as age and other medical health. But depending on the size if we find a small tumor that’s not very symptomatic one option is always observation. Like I mentioned before these are benign tumors and so they are slow growing. On average they grow about one to two millimeters a year. If you find a one or two-millimeter tumor by chance in somebody who is ninety years old observation may be a very reasonable option. In other patients who are having symptoms or who for example, might be younger the other options if we decide to treat the tumor or if they wish to be treated is either surgery or radiation. Radiation in the form of what falls under the broader category of stereotactic Radiosurgery, or basically a very focused radiation. And the way that works is that there’s different methods of delivering radiation. What we use most commonly is something called gamma knife. It’s not a knife at all but basically it’s describing the precession of the instrument. This machine delivers multiple beams of radiation that all converge on one point which would be the tumor and that helps to deliver a much higher dose of radiation to that tumor. When we choose radiation after discussing it with patients the control rate of basically preventing the patient from needing subsequent treatments which could be either more radiation or surgery is about eighty five to ninety five percent. Not all tumors can be treated with radiation. Some tumors either because they’re too big, patients are too symptomatic, then surgery becomes the next option.
You had mentioned that this was a slow growing tumor, is it possible then that these can go undetected for quite some time?
Dr. Gandhi: Very commonly yes. We will often find these tumors very late in to the diagnosis. Sometimes you’ll find out that maybe patients have been having a gradual hearing loss over time. More that they were completely asymptomatic until one day they just noticed that I’m having hearing problems or I’m having dizziness and you find these tumors that are you know thirty millimeters and they’ve been growing maybe for fifteen to twenty years completely unnoticed. And that’s a very common scenario.
Does earlier diagnosis make a difference? Is there a way to diagnose early?
Dr. Gandhi: Well certainly we don’t want people becoming paranoid that they have these types of tumors. This tumor is still relatively rare, it’s less than ten percent of all tumors that we find in the brain or in the skull. And the incidence of this type of tumor is about one in a hundred thousand or two to three thousand new tumors are diagnosed per year. Patients who don’t have symptoms you know shouldn’t be worried about it. It’s not associated with cell phone usage or anything like that, none of that has been proven. People sometimes think that there’s a higher rate of finding these tumors and it’s just because getting MRI’s for other reasons is more common. A lot of times we’ll even find these tumors because a patient had an MRI for some other completely unrelated reason. Yes though to answer your question when we find these tumors at a smaller size treatment is easier either from a radiation standpoint or even from surgery. The outcomes after surgery in a smaller tumor are much more predictable and often times better.
Just a little bit about the surgery. This is a fairly complicated surgery in a lot of cases?
Dr. Gandhi: Yes. What makes the surgery complicated is more so the interrelationship of this tumors with these nerves. Of course, the tumor is growing off of one of these nerve rootlets and so often displaces these other nerves that in very close proximity to each other. As the tumor grows it gets more entwined with the other nerves. Obviously our goal for surgery is to keep patients functional. We don’t want patients having facial weakness. And often we want to try to preserve hearing if they still have functional hearing in that ear. That makes surgery much more complicated because we’re taking a tumor and peeling it off the nerves often times peeling off the brain stem. That can make it very difficult.
Is this a long surgery?
Dr. Gandhi: I tell patients that if I didn’t have to worry about the outcome of how they were feeling after surgery we could just cut the nerve and cut the tumor and we’d be done in probably thirty minutes. But because we must worry about these things and that’s very, very important in doing these surgeries because again they are benign tumors and our goal is to stop them from progressing or becoming symptomatic. Yes surgery does take longer than some of the other surgeries that we do because of that care that’s needed to very meticulously dissect that tumor away from these other nerves, to identify the nerves and monitor the function. We use electrical monitoring during the procedure to monitor patient’s facial function, their hearing, all while they’re asleep during the surgery.
Is there a team approach then with the longer surgery?
Dr. Gandhi: Yes, it’s a very enjoyable surgery for us because we get to work with our colleagues. The Ear, Nose and Throat Surgeons to or Neurotologist their subspecialty within Ear, Nose and Throat surgery. They will help us with the approach and then we work together on taking out the tumor. Like you had mentioned these tumors often take a long time and so it’s very beneficial to have two surgeons working together to kind of go over what we’re doing as we’re doing it. It’s a very nice and elegant surgery. The most common way to approach this tumor is to go from behind the ear but there are different alternatives for the type of approach to the tumor based on the exact location.
Just recovery, what can patients expect after surgery?
Dr. Gandhi: The most common thing is that patients will have some headache as expected but it’s not a terribly painful surgery. Patients often will have some nausea just associated with the anesthesia and also having had your head opened. But patients do relatively well. We like to get our patients up right away so whenever we finish surgery we want our patients up in a chair, walking the evening of the surgery or at least the next morning. We like to mobilize our patients early and get them back in to a routine. They’ll need some physical therapy sometimes they’ll need some help with balance. Usually patients will spend a day in ICU just for very close monitoring of their neurologic function. And then they move on get through the hospital usually in about three days is an average expectation.
How long before they are back to themselves, is it a three month process?
Dr. Gandhi: Patients generally are in pretty good shape by six weeks. I generally ask patients to take it easy for the first couple weeks and then slowly start increasing their activity. We don’t want them doing any rigorous things that they’re not quite ready for. Sometimes it’s actually the opposite of what you might expect. Patients feel so good that they overdo their activity after surgery and then realize wait, I’m not quite ready for that. By six weeks patients are usually pretty ready to get back in to the swing of their normal life.
Is there anything I didn’t ask you that you want people to know?
Dr. Gandhi: No I think we kind of addressed all of the basics.
What’s the success rate for most of these surgeries?’
Dr. Gandhi: That’s a good question. The success rate with surgery is dependent a lot with the size of the tumor. When we talk about these tumors we kind of divide them in to three size groups. And how we judge success is based on sort of two things. The preservation of facial function, hearing, if they had functional hearing beforehand, a lot of patients present with almost no hearing or no functional hearing. And then the amount of tumor that was resected. For smaller tumors the success rate is obviously much higher. Facial preservation is greater than ninety percent, meaning no weakness in the face on that same side of the tumor. That is obviously better in places by surgeons that do a lot of these tumors. I’m sure our numbers are probably much better than that. Patients might just have transient weakness that will get better over the next few weeks. As the tumors get larger the risk to injury to that nerve, the facial nerve goes up. And sometimes it’s not necessarily anything that we do just that these nerves have been so stretched for so long that any kind of manipulation can lead to a dysfunction in that nerve. Dysfunction is temporary and we take a lot of precaution to try to prevent that from happening. The amount of tumor that’s resected, because we know that we have the alternative to radiate a small portion of tumor that gets left we now have shifted the paradigm of what we do during surgery. Back when they first started doing the surgery they would be very aggressive to resect the tumor. Even if it meant that they knew they were going to leave somebody with a weak face. We now put such a big emphasis on facial preservation that if necessary we will sometimes leave a small piece of the tumor knowing that even if left alone that tumor may grow for a very long time before it becomes symptomatic. Or if it shows any growth we can always do that radiation to a very small piece of the tumor left behind.
END OF INTERVIEW
This information is intended for additional research purposes only. It is not to be used as a prescription or advice from Ivanhoe Broadcast News, Inc. or any medical professional interviewed. Ivanhoe Broadcast News, Inc. assumes no responsibility for the depth or accuracy of physician statements. Procedures or medicines apply to different people and medical factors; always consult your physician on medical matters.
If you would like more information, please contact:
Karina Saad
352-989-2925
Ravi H Gandhi
Dr.gandhi@orlandoneurosurgery.com
407-975-0200
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