Article
Anatomical considerations for the endoscopic transcranial approach-routes via retrosigmoid craniotomy: surgical windows and zones in the cisterns of the posterior fossa
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Authors
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Peter Kurucz
- Department of Neurosurgery, Klinikum Stuttgart, Stuttgart, Deutschland; Laboratory for Applied and Clinical Anatomy, Semmelweis University, Budapest, Hungary
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Firas Thaher
- Department of Neurosurgery, Klinikum Stuttgart, Stuttgart, Deutschland
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Oliver Ganslandt
- Department of Neurosurgery, Klinikum Stuttgart, Stuttgart, Deutschland
| Published: | June 2, 2015 |
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Outline
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Objective: The use of endoscopes as an additional tool to the operating microscope during surgery through the retrosigmoid approach is already a well-accepted technique and anatomically increasingly studied. The goal of our examination was to exactly define the anatomical relations of the numerous intracranial approach-routes through the retrosigmoid craniotomy and their limitations which are elementary for the safe manipulations and inspections with the scope.
Method: Our study was performed on cadaveric specimens as well as on live cases. Endoscope-controlled retrosigmoid approaches were performed on 25 fresh human cadaveric specimens. It was followed by analyzing of 31 live operations with different pathologies: 11 microvascular decompressions, 17 skull base tumors and 3 vascular cases.
Results: In our definition the surgical windows are spaces surrounded by important neurovascular structures which are acting as a natural frame and providing safe access to the deeper situated structures. The zones are smaller compartments of the subarachnoid cisterns surrounded by surgical windows. Endoscopic approaches could be interpreted as vector-like trajectories starting at the craniotomy and pointing to the target lesion, passing through one or more surgical windows and zones. Depending from the craniotomy the neurovascular structures are forming different surgical windows and zones. The windows also limit the freedom of movements and sight therefore the endoscopic approach-routes to the target lesion have to be individually planned before the operation based on the specific pathoanatomical situations of the patient. In the posterior fossa we could define 13 surgical windows organized along 3 parallel lines and surrounded by 5 zones. We described the visible neurovascular and arachnoid structures and areas viewed through these windows as well as the limitations of each endoscopic approach-route through the retrosigmoid craniotomy.
Conclusions: Our anatomical results are the essential basics of a "mental roadmap" to safely but maximally effectively perform endoscopic procedures in the posterior fossa cisterns through the retrosigmoid approach.
