Elekta, Inc. photo of new Perfexion® Gamma Knife.

Dr. Michael Sisti from the Gamma Knife Center tells us a multi-million dollar up-grade is coming to his Center this Summer.  They will be upgrading to a new state-of-the-art (5 million dollar plus) machine called the Gamma Knife Perfexion System.

The Gamma Knife isn’t really a knife, but a large machine that generates a highly concentrated beam of radiation that is used to specifically target a lesion in the brain.

The Gamma Knife is used to treat a multitude of problems including Brain Tumors, Cerebral Arteriovenous Malformations (AVMs), and Epilepsy.

The upgrade to the Perfexion system expands this capability to include more treatment areas.  Also, an advanced planning system means surgery will be performed with even greater accuracy.

According to Elekta, the maker of the Perfexion System, “System benefits include faster set-up and treatment delivery to one or more tumors in a single session[.]”

Watch this video to learn more about the new Perfexion Gamma Knife.

Dr. Sisti is excited about his Center‘s upgrade.  He says, “We will then have the two ultimate radiosurgery systems: Trilogy and Gamma Perfexion in one place.”

Also of note is that the whole Radiation Oncology Department at Columbia is undergoing a $50 million upgrade.  This is important to our cancer patients because many of them will receive their radiation therapy there.

Learn more from our page on Gamma Knife Radiosurgery and our previous blogs: One Picture Speaks a Thousand Words-These Neurosurgeons use Two and Radiosurgery Trials Looking Good for Epileptics.

The doctors named are: Robert A. Solomon, M.D., Department Chair and part of the Cerebrovascular Center; Michael B. Sisti, M.D. from the Brain Tumor Center and Gamma Knife Center;  Paul C. McCormick, M.D., M.P.H., from the Spine Center; and  Steven R. Isaacson, M.D. from the Gamma Knife Center.

Every one of these doctors also has the designation of being one of America’s Top Doctors (ATD) for 2010 as chosen by Castle Connolly.

Congratulations Doctors!

First he was spotlighted as the 2009 NREF/Spine and Peripheral Nerves Section Research Fellow for his paper entitled, A Novel Approach for Convection Enhanced Delivery of Nerve Growth Factors in a Peripheral Nerve Bridge Model to Bypass Spinal Cord Injury.

Dr. Sisti with Dr. Haque

He also won the Leksell Radiosurgery Award, which, according to the AANS website is for, “the best paper on stereotactic radiosurgery related to brain tumors.”   His paper was called, Efficacy of Facial Nerve-Sparing Microsurgery and Stereotactic Radiosurgery with Gamma Knife in Preserving Facial Nerve Function in Patients with Recurrent Acoustic Neuroma.

Finally, Dr. Haque was recognized as one of the authors of the AANS Medical Student Summer Research Fellowship paper entitled, Neural Proliferation of Bone Marrow Derived Cells in a Murine Model of Intracerebral Hemmorrhage.

Dr. Haque joined by his parents, Dr. Bruce and Dr. Sisti

Way to go Dr. Haque!

A Cerebral Arteriovenous Malformation (AVM) is a rare tangle of blood vessels in the brain that carries a high risk of hemorrhaging.  Brain surgeons have found that “gluing” or blocking off the blood supply to these malformations before surgery cuts down on blood loss and patients do better.  Dr. Robert Solomon along with several other neurosurgeons from the Department of Neurosurgery recently took a close look at the risks associated with this procedure, and the results were encouraging.

This process of  ”gluing” is actually called embolization, a procedure that starts by inserting a tube into an artery in the patient’s groin.  Through this tube surgeons use tiny instruments to snake their way through arteries to the problem area in the brain.  Once there, they inject a glue like substance that blocks off the blood supply to the AVM.

Embolization was first developed in 1968 and for a long time it was used as a primary treatment for AVM.  Used alone however, it wasn’t as successful as surgeons wanted.  Over the next couple of decades, advances in microsurgery (that is surgery with tiny instruments and the use of a microscope) enabled surgeons to completely remove the AVM.

By 1997, with the opening of the Gamma Knife Center, surgeons were using a multi step, multi-technique approach that was resulting in better outcomes and saving more lives.  It became standard practice at Columbia Medical Center to perform an AVM embolization before either microsurgery or Radiosurgery with the Gamma Knife.

Of course, the story does not stop there.  Medicine is ever evolving and surgeons are always looking for better ways to help their patients.  One of the ways they do this is by performing retrospective studies.  They look at surgical cases over a period of several years and correlate the procedures done with the outcomes.  By doing this, they come up with ways to further refine and improve their methods.

Dr. Solomon and his team did just that when they looked at the outcomes of over 200 AVM patients since 1997 who underwent embolization.  They knew that embolization before surgery was beneficial but they wanted to quantify any downside.

They looked to see if the procedure itself was the cause of any neurological problems.  Using this data they also hoped to find any patterns that could predict the occurrence of deficits in patients to better control for them.

What they found overall was that the risk of performing the embolization itself was low.  Of the 202 patients only five had any lasting deficits, that is only about 2%.

Furthermore, they were able to come up with a number of predictors for these problems.  One was the size of the AVM.  When the AVM was larger than 6 cm in diameter the risk increased.  There was also a slightly increased risk when the AVM was smaller than 3 cm.

Another risk factor they found was the number of procedures needed to complete the job.  In some cases, it was necessary to perform more than one embolization in which case the risk of poor side effect went up.  But only minimally.

The last two factors that they discovered were the location of the AVM and whether or not it had a large venous drainage.

Having predictive factors like these will help surgeons choose more carefully who receives exactly what kind of treatment and improve the patients chances of a good outcome.  In the end, the risk proved to be quite small and, by a long shot, didn’t outweigh the benefits of this procedure.

To learn more see their paper, Adjuvant Embolization With N-Butyl Cyanoacrylate in theTreatment of Cerebral Arteriovenous Malformations in the on-line journal Stroke (2009;40:2783)

This study was multi-institutional and included the following co-authors from the Department of Neurosuregy: Michael Sisti, MD from the Gamma Knife Center; and Robert Solomon, MD ; Sean Lavine, MD; E. Sander Connolly, MD; and Philip Meyers, MD from the Cerebrovascular Center.

Other blogs about AVM: A Protein In The Blood May Be A Clue To Arteriovenous Malformations In The Brain, How Does A Neurosurgeon Know What To Say When An AVM Patient Asks, “What Are My Chances Doc?”, One Picture Speaks A Thousand Words, These Radiosurgeons Use Two

A Gamma Knife isn’t really a knife. It is a large, stationary machine that can generate a highly concentrated beam of radiation to target a specific location in the brain. It is often used in the treatment of brain tumors. The Gamma rays are painless and the procedure is most often done in an outpatient visit. Typically only one treatment is needed. In this trial the treatment was specifically directed to a location on one side of the brain where the seizures occurred.

Thirty people with epilepsy that have at least three seizures a month were asked if they wanted to be part of this trial. In the end, 26 patients completed the course of the study. These patients were each treated at one of 15 different centers across the country, including our Epilepsy Center here in New York. The patients were divided into two groups: one that received a high intensity dose and one that received a low intensity dose.

They were observed over a period of three years and about 60% of all these patients were completely seizure free by the end. This is comparable to the results of open brain surgery. The differences between the two groups were minimal but the high intensity group tended to have a higher chance of achieving seizure freedom.

What is interesting about the results using the Gamma Knife compared to open surgery is the time it takes to get results. With open surgery, seizures and accompanying auras are immediately stopped. With Gamma Knife Radiosurgery, it can take up to a year for the seizures to go away and in this study, the auras intensified for a brief time even after the seizures stopped.

In some cases, the Gamma Knife patients had an increase in headaches and slight decreases in verbal memory. Over all though, there were no significantly adverse effects from the procedure and the outcome was comparable to the results of open brain surgery without all the risks and complications that entails.

To learn more look for the paper: A Multi-Center, Prospective Pilot Study of Gamma Knife Radiosurgery for Mesial Temporal Lobe Epilepsy: Seizure Response, Adverse Events, and Verbal Memory in the online journal Annals of Neurology Volume 65, Issue 2.