gms | German Medical Science

Objective: Improvement in surgical techniques allocates enormous development in transcranial and transnasal neurosurgery treating more complicated diseases through limited minimally invasive approaches. Limited approaches may offer reduced approach-related traumatisation, however, they can cause limited orientation in the deep-seated surgical field. For allowing adequate intraoperative exposure the optical properties of surgical microscopes can be effectively supplemented by the intraoperative use of endoscopes. In addition, the intraoperative use of navigation systems and real-time imaging e.g. ultrasound, intraoperative CT (iCT) and MRI may be helpful if the limited cranial opening leads to a confusing and purely overviewed situation.

Methods: In this report, we have overviewed our preliminary experience in intraoperative use of iCT in transcranial and transnasal endoscopic skull base surgery. During a one-year period between December 2009 November 2010, we have used iCT during 102 consecutive neuroendoscopic operations. There were 90 transcranial and 12 transnasal operations. The integrated CT-navigation tool (BrainSUITE iCT, BrainLAB, Feldkirchen, Germany) was used for registration of the navigation device, controlling tumour removal and excluding operative complications.

Results: The intraoperative use of CT allowed precise registration of the navigation device. During our learning curve, in 7 cases technical pitfalls occurred, thus making optical registration necessary. iCT allowed safe intraoperative control on tumour resection; in three cases, iCT assisted exact localisation of endoscopically presumed residual tumour. In one case of a cystic lesion with massive intraoperative shifting, re-registration of the navigation tool was mandatory for safe intraoperative orientation. In one case, severe epidural hematoma could be detected during surgery, thus making emergency evacuation possible.

Conclusions: The endoscopic visualization allowed exquisite intraoperative anatomical orientation, increased light intensity in the deep seated surgical field with an extended viewing angle and clear depiction of surgical details in close-up position. With additional use of iCT, the tumour removal could be effectively controlled especially in hidden parts of the surgical field.