Neurosurgeon Case Studies

• Navigated Resection of a Brainstem Cavernous Malformation
• A Total Resection of an Intraventricular Mass Using Surgical Navigation

Navigated Resection of a Brainstem Cavernous Malformation

Patient Profile

Thirty-four-year-old female with a longstanding history of mild, right-sided hemiparesis and left visual disturbance was evaluated by the Barrow Neurological Institute, complaining of a sudden, severe headache accompanied by nausea and vomiting. MR imaging revealed a left pontine and cerebral peduncle cavernous malformation, measuring approximately 3.5 x 2.5 x 1.0 cm in size with evidence of old and new hemorrhage. Following information regarding the risks of surgery, the patient made the decision to proceed with surgical resection of the lesion, utilizing an orbitozygomatic craniotomy.

Operation

Prior to surgery, the patient had fiducial markers carefully placed on her head, then underwent gadolinium enhanced MR imaging, using the StealthStation^® protocol. After anesthesia and fixation of the head holder, the StealthStation^® TREON^® Treatment Guidance System was registered to the patient using a standard paired-point PointMerge^® image correlation. Surgery commenced once image correlation was tested and verified. After the craniotomy and osteotomy were performed and the dura retracted, Robert Spetzler, MD, and his team carefully worked their way down to the cavernous malformation. Here again, Dr. Spetzler utilized the StealthStation^® system, incorporating an integrated Zeiss OPMI^® Neuro/NC4 microscope with MultiVision™ image injection system as a navigational probe. After identifying the exact entry point on the brainstem utilizing the image-guided system, a series of microdissectors were used to gently dissect the cavernous malformation from the surrounding brainstem. Because of the cavernous malformation’s large size, Dr. Spetzler again used the StealthStation^® system to assist in dissecting the lesion along its margins, respecting a plane between the cavernous malformation and the adjacent neural tissue.

Conclusion

The patient tolerated the procedure without apparent complication and was taken to the recovery room with stable vital signs. Postoperative CT imaging the day after surgery revealed excellent resection. Following a brief recovery period at the hospital, the patient was discharged to home with no new deficits and is slowly recovering from her previous disability.

Comments

“The introduction of image guidance such as the StealthStation^® system integrated to the Zeiss OPMI^® Neuro/NC4 microscope has made it possible, for the first time, to remove deep and difficult lesions such as cavernous malformations from such previously inoperable regions as the brainstem. We have removed well over 100 brainstem cavernous malformations that were invisible when the brainstem had been exposed and their localization and subsequent resection was completely dependent on the information provided by the StealthStation^® system. There is no question that image guidance has expanded our operative capabilities and led to fewer complications. I depend on it on a daily basis.” - Robert Spetzler, MD, Neurosurgeon, Barrow Neurological Institute, Phoenix, AZ

A Total Resection of an Intraventricular Mass Using Surgical Navigation

Patient Profile

38-year-old female presented with a history of headaches and a normal neurological examination with no prior neurosurgical procedures. Her initial MRI revealed an intraventricular mass and she was medically managed until her six-month follow-up MRI revealed an enlargement of the 2cm enhancing intraventricular mass. After the risks and benefits of surgery were explained to the patient, she decided to proceed with a surgical resection of the mass.

Operation

The patient underwent a gadolinium MRI with fiducials placed pre-operatively. In the prone position, patient’s head was fixed with a Mayfield^® head holder, a StealthStation^® cranial reference arc attached, registered and verified. Initially the StealthStation^® TREON^® Treatment Guidance System was used to outline a hair-sparing cranial incision. James Chandler, MD, resected the deep-seated intraventricular lesion, with a minimally invasive approach, using a parieto-occipital craniotomy and guidance with the StealthStation^® system. Dr. Chandler was able to minimize the bone and cortical exposure. He again used the StealthStation^® system to safely access the ventricular system, which housed the mass, while traversing the least amount of cortical surface. The entire mass lesion was removed utilizing a gentle microdissection technique under the guidance of the Leica^® OHS-1 microscope with laser as pointer.

Conclusions

The patient recovered from surgery with no neurological deficits. A 24-hour post-operative enhancing MRI confirmed a gross total resection of the lesion, and no other abnormal findings. The patient was released neurologically intact from the hospital after a three-day post-operative recovery period.

Comments

“The advantage of utilizing a surgical navigation system is for the surgeon to assure the patient the absolute safest surgery possible while ensuring a confidence of a total resection of the lesion. I’m impressed with the StealthStation^® image guidance system and what it has allowed me to accomplish in the operating room.” - James Chandler, MD Neurosurgeon Northwestern Memorial Hospital Chicago, Illinois

NOTE: Each experience described here is specific to a particular patient. Results vary and every response is not the same. Patients should always talk with their doctors to see if they may benefit from this therapy and for a full review of indications and side effects.