Pediatric Case Study:
Recently a patient was admitted to Boston Children's Hospital under the care of Robert Tasker, MD, director of Children's new Neurocritical Care Program, with a severe headache and sudden loss of coordination on her left side. A CAT scan revealed bleeding in the left cerebellum, near the brainstem - an important area for coordination, movement, breathing and cardiovascular control.
MRI SHOWS THE HEMORRHAGE
Cerebellar vernis and hemisphere to the left of midline and its effect on surrounding brain tissue (lime arrow).
To better understand the anatomy of what caused the bleeding, other tests- including an angiogram performed by Darren Orbach, MD, PhD, director of Neurointerventional Radiology - revealed an arteriovenous malformation (AVM), one of the most common neurovascular problems in children.
AVMs are abnormal tangles of blood vessels that are formed before children are born. With rare exceptions, they are almost never genetic. It is unclear why they suddenly bleed - some sit dormant for decades and others can bleed shortly after birth. Unfortunately, there are no good screening tests for these lesions, although research is ongoing at several centers, including Children's, in the laboratory of Edward Robert Smith, MD, director of Pediatric Cerebrovascular Surgery.
Treating the Bleed
Once discovered, if an AVM has bled—as was the case here—there is usually a need to treat it. This can be done with radiation, gluing the blood vessels shut from within (embolization), or surgery. In this case, the recommendation of our multidisciplinary group was to operate, with the goal of removing the entire AVM. Dr. Smith resected the lesion in Children’s MR/OR, the first intraoperative MRI in a pediatric hospital.
Oftentimes if the child is stable, it is advantageous to wait a few weeks to allow the swelling from the bleeding to diminish, which makes an operation safer. This was particularly important with this recent case, as the AVM was challenging due to its location.
The surgery required inserting a small tube to relieve pressure on the brain by draining some spinal fluid, then navigating a narrow corridor between the vision center (the occipital lobe), cerebellum and brainstem.
To get to the AVM, a thick membrane—the entorium—was cut, as it divides the occipital lobe from the cerebellum and brainstem. The opening was made, allowing Dr. Smith to gain access to this small area, using a microscope and computerized guidance device that is similar to a GPS. The surgery here can be difficult, as the work is done in a very small space—about the size of a dime— performed through a 5-inch-long narrow tube of access.
CATHETER ANGIOGRAM, frontal view: Subtle early opacification of a small cluster of veins, before the time of the expected appearance of the venous structures (blue arrows). The finding is consistent with an arteriovenous malformation (AVM).
Anatomy of AVM
The blood vessels entering the AVM need to be cauterized before the draining veins. If a mistake is made in identifying these vessels, then blood will continue to enter the AVM with no way to exit, leading to a very dangerous situation in which the AVM can rupture during the operation.
The preoperative imaging provided by Radiology—coupled with anesthesia by Mary Landrigan-Ossar, MD, PhD, and Craig McClain, MD, MPH, during resection of the entire AVM and an angiogram after the procedure to confirm its success— allowed for a very safe surgery. The child awakened at the end of a full day of two angiography procedures and brain surgery talking and fully recovered.
WORLD's FIRST, pediatric MR/CR with a 1.5 Testa MRI scanner
Neurocritical care and the work of the intensivist are about seeing the patient’s problem from the perspective of each of the specialists and targeting physiology to deliver the best outcome— which was, in this case, optimizing brain blood flow during and after care of the patient. Once in the intensive care unit, the team constructed a plan of care tailored to the patient.
Our goal at Children’s is to make patient care as seamless and safe as possible, from the moment of arrival at the hospital to discharge home. This was the case with the patient referenced, whose treatment was successful.