{'fraction_non_alphanumeric': 0.015033407572383074, 'fraction_numerical': 0.005567928730512249, 'mean_word_length': 5.781132075471698, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Photodynamic application in neurosurgery: present and future

Photodynamic techniques such as photodynamic diagnosis (PDD), fluorescence guided tumor resection (FGR) and photodynamic therapy (PDT) are currently undergoing intensive clinical investigations as adjunctive treatment for malignant brain tumours. This review provides an overview on the current clinical data and trials as well as on photosensitisers, technical developments and indications for photodynamic application in Neurosurgery. Furthermore new developments and clinical significance of FGR for neurosurgery will be discussed. Over 1000 patients were enrolled in various clinical phase I/II trials for PDT for malignant brain tumours. Despite various treatment protocols, variation of photosensitisers and light dose there is a clear trend towards prolonging median survival after one single PDT as compared to conventional therapeutic modalities. The median survival after PDT for primary glioblastoma multiforme WHO IV was 19 months and for recurrent GBM 9 months as compared to standard convential treatment which is 15 months and 3 months, respectively. FGR in combination with adjunctive radiation was significantly superior to standard surgical resection followed by radiation. The combination of FGR/PDD and intraoperative PDT increased significantly survival in recurrent glioblastoma patients. The combination of PDD/ FGR and PDT offers an exciting approach to the treatment of malignant brain tumours "to see and to treat." PDT was generally well tolerated and side effects consisted of occasionally increased intracranial pressure and prolonged skin sensitivity against direct sunlight. This review covers the current available data and draws the future potential of PDD and PDT for its application in neurosurgery.