SleepTalker April 2016

Stephen Probst, MD
   In this article I discuss the new Apollo system for treatment of intracranial hemorrhage. I briefly discuss intracranial hemorrhage (ICH), the historic difficulties treating this condition, the Apollo procedure itself and how it is a hopeful advance in the treatment of ICH.
   Intracranial hemorrhage, or bleeding within the brain, represents the most devastating type of stroke. ICH has the highest rates of associated morbidity and mortality. No specific medical or surgical interventions have been shown to improve outcomes in patients with ICH. Most patients are treated with blood pressure control and supportive medical care only. They typically spend many days within the ICU and hospital. Survivors are very often permanently disabled.
   The neurological injury created by parenchymal hemorrhage is thought to have two distinct phases. Initially, there is direct injury to regional brain tissue through simple mechanical disruption by the hemorrhage.¹ In the hours and days that follow, additional injury to the surrounding brain tissue occurs. This is believed to be a direct result of the toxic effect of blood products on the brain as well as a local mass effect from the hematoma.² The regional injury surrounding the hematoma can be seen on neuroimaging as perihematomal edema (PHE). PHE and its associated mass effect, increases quickly within the first 24 h, peaks at 5–6 days, and then may begin to resolve.³
   It was suggested that early evacuation of the hematoma might mitigate or eliminate the delayed injury. However, trials of surgical hematoma evacuation failed to show any clinical benefit.⁴ This failure might be due to injury of normal brain tissue by the surgical approach to the hematoma, particularly for deep hemorrhages. Thus, a less invasive means of hematoma evacuation could potentially be beneficial. A series of small, yet encouraging, case series and trials led to the Minimally Invasive Surgery and Tissue Plasminogen Activator (tPA) in Intracerebral Hemorrhage Evacuation (MISTIE II) trial, which compared a strategy of minimally invasive hematoma drainage with medical management.⁵ The intervention consisted of stereotactically guided manual syringe aspiration of the hematoma followed by placement of a drainage catheter within the cavity, which could be irrigated with tPA to maintain its patency.⁶ The trial showed that this interventional procedure reduced PHE, reduced length of stay and improved clinical outcomes measured at 1 year. The results indicated that, in general, greater reductions in clot size correlated with better patient outcomes, especially if the clot volume could be reduced to under 10 mL. However, this degree of clot reduction was rarely achieved in MISTIE II patients, even after days of catheter irrigation with tPA. The average volume of residual clot at the end of treatment in MISTIE II was 19.6 mL.^6,7

   The Apollo procedure is a new endoscopically guided irrigation–aspiration system recently cleared by the US Food and Drug Administration for the evacuation of intracranial hemorrhage. The Apollo procedure can be performed through a small hole in the patient’s skull. With imaging guidance, the Apollo Wand (a small suction tube) can be placed through this hole and into the region of the brain bleed.
   The Apollo Program at Stony Brook University Medical Center is led by Dr. David Fiorella and has published multiple papers on the system ranging from proof of concept with cadavers to small case series involving patients. Results have been extremely promising thus far.
   The procedure maintains the concept of using a minimally invasive approach to evacuate an ICH to reduce PHE, while minimizing procedure-related damage to brain tissue. The Apollo system further builds upon this concept by utilizing neuronavigation to plan the surgical approach, place the endoscopic working sheath, and assess the location of the sheath with respect to the hematoma throughout the procedure.⁸ Secondly, endoscopic imaging is used for the entire procedure allowing visualization of the operative area, the Apollo wand during aspiration and actuation, location of residual hemorrhage for targeted aspiration and differentiation between hematoma and surrounding brain tissue.⁸ This direct visualization of the interaction between the Apollo wand and the hematoma allows strategic manipulation of the wand to optimize the efficiency of clot removal.⁸

   The procedure can be done in the neurointerventional suite, utilizing real time Dyna CT to evaluate residual clot volume or in the operating room, with a post operative CT. Anesthetic concerns for this procedure are as per other neurosurgical procedures: appropriate blood pressure management so as to maintain adequate cerebral blood flow, immobility to ensure adequate neuroimaging, keen awareness of location of monitors and lines so as not to interfere with the multiple pieces of equipment necessary for the procedure. Rapid communication of hemodynamic changes are necessary as a blockage in the suction-irrigator can rapidly lead to a Cushing response.
   A multicenter randomized trial comparing the Apollo procedure to standard medical management for the treatment of cerebral hemorrhage is expected to begin in the near future. We are hopeful that future research will demonstrate that the Apollo procedure improves outcomes in ICH and finally offer hope to patients suffering from this disease.
   References