International Physician Update

Olivi Goes Boldly with Brainstem Biopsy 

Alessandro Olivi, right, has performed more than two dozen brainstem biopsies.

Looking at the trajectory of Alessandro Olivi’s biopsy needle is something that could curl the hair of the uninitiated. The needle traverses the brain diagonally, barely skirting the ventricle.   And then, passing into no man’s land, it enters the brainstem, site of the nerve centers for breathing, regulating blood pressure and heart rate, eye movement and swallowing, among other functions.

“Because of the concentration of high-function brain tissue in a small area, the brainstem’s been thought offlimits for any kind of biopsy,” says neurosurgeon Olivi. And while retrieving tissue isn’t novel, it is uncommon. Olivi has performed more than two dozen of the procedures.  “The greatest worry with brain biopsy is hemorrhage,” he explains.

Some pathologists mark blood vessels tissue-fragile. Even a small bleed can be devastating in the brainstem. “We tell patients there’s a 3 percent risk of that, but so far, we’ve had no hematomas, no hemorrhagic complications.”

Brainstem biopsy is the method of choice to identify and grade tumors and distinguish them from localized inflammation. And while subsequent surgery is typically ruled out in the brainstem—save for tumors that extend beyond it—biopsy is key to making a prognosis and planning the usual option, radiation therapy.

Prior to the biopsy, a patient is fitted with a stereotactic headframe. Next comes an MRI, which Olivi uses to plot his path, measuring distance and angle while at the MRI console, to trace the least risky approach. The patient then moves to the OR for the biopsy.  That, surprisingly, is done under local anesthetic and sedation. Affixing a metal arc to the patient’s headframe, Olivi slides a movable holder around the arc, aligning the biopsy needle so it becomes the radius of a circle whose center is the target tissue.

After he’s made a pea-size burr hole in the posterior front skull, Olivi slowly feeds the needle into the brain, extracting a bit of tissue via an interior stylet.  A quick pathologist’s report tells if the tissue’s right for analysis.