Confocal Laser Endomicroscopy in Neurosurgery-An Alternative to Instantaneous Sections?

OBJECTIVE: Intraoperative distinction of brain tumor from surrounding brain is a crucial challenge in neuro-oncologic surgery. We directly compared confocal laser endomicroscopy (CLE) findings with intraoperative instantaneous sections by the neuropathologist in a blinded fashion.

METHODS: The imaging device comprises a rigid endoscope with Hopkins rod lenses and a red wave length laser with a scanning depth of 80 μm. Brain tumor samples of 100 patients were investigated. Tissue samples were simultaneously investigated by the neuropathologist and with CLE. The tissue was not prepared or stained before CLE analysis.

RESULTS: CLE could be performed in all cases. Sensitivity for detection of a correct final diagnosis by CLE on site was 82%-90% for high-grade gliomas (26/32), low-grade gliomas (9/10), schwannomas (7/8), and meningiomas (28/34). Sensitivity of only 37% (6/16) was achieved for metastasis (6/16).

CONCLUSIONS: With intraoperative CLE, it is possible to obtain an on-site histologic diagnosis with a high sensitivity in many tumors. Although definitive histologic classification requires further neuropathologic investigation, these results show that CLE could fill the gap between tissue resection and microscopic analysis. This could ultimately help neurosurgeons to scan brain tissue for tumor remnants on a microscopic scale without having to resect it first. Further development of the device and further investigations are needed before this technique can become part of the neurosurgical routine in specific cases.