雷射在神經外科的應用

Laser Application in Neurosurgery

雷射發明之後，很快就被應用在神經外科手術，初期主要用來做為手術切割及止血的工具，後來配合手術顯微鏡及內視鏡進行精細準確的手術，應用於腦瘤的切除，電視內視鏡雷射交感神經切除手術治療手汗症，以及經皮雷射椎間盤減壓手術治療椎間盤突出症。之後雷射熱潮逐漸在神經外科消退，轉往光動力醫學方面發展。光動力醫學，包含光動力診斷、螢光導引腫瘤切除、及光動力治療，能夠作為惡性腦部腫瘤的輔助性治療，目前相當受到矚目。螢光導引腫瘤切除術可以提高腫瘤完全切除率，延長病人的存活，改善病人的預後。光動力治療能夠殺滅手術後殘留的腫瘤細胞，不傷害周圍正常的腦組織，而且可以重覆給予，對具有多重抗藥性的腫瘤亦有療效，亦可以與其他的治療方法同時進行，適合作為手術中或手術後的輔佐治療。對於侵犯腦部重要功能部位的腫瘤，為了保全正常神經學功能，因而無法完全切除腫瘤組織，此時術中針對殘留腫瘤組織進行光動力治療或許是很合適的選擇。大多數的病人對光動力治療有相當好的耐受性，少數病人可能有腦壓上升及皮膚光過敏等副作用。新光感物質的開發以及光源系統的改進能夠促進光動力治療的發展，若能開發同時具有良好螢光反應及光動力效應的光感物質，可以達到診斷與治療雙效合一的效果。

Ever since the development of laser, it has been applied to neurosurgery. It was used as a tool for cutting tissue and hemostasis initially, and then was combined with the use of microscope and endoscope for precise surgery of brain tumor, palmar hyperhidrosis, and percutaneous laser disc decompression. Later on, the laser enthusiasm tempered and shifted to photodynamic medicine. Photodynamic medicine is a broad field including photodynamic diagnosis (PDD), fluorescence-guided resection (FGR) of tumor, and photodynamic therapy (PDT). This field attract increasing attention today. Fluorescence-guided resection enables more complete resection of tumors, leading to prolonged survival and improved prognosis in patients with malignant glioma. After maximal excision of tumor, PDT can selectively destroy the residual tumor cells without causing damage to the surrounding normal brain tissue. PDT is also effective in killing multi-drug resistant cancer cells and can be applied repeatedly. PDT can be used intra-operatively or post-operatively as an adjunctive therapy, it can also be coupled to other therapies. For patients with tumor involving the eloquent region of the brain, complete resection of the tumor is not possible, thus intra-operative PDT could be a good choice in such circumstances. Most patients tolerate PDT well; adverse effects including increased intracranial pressure and skin allergic reaction. The development of better photosensitizer and refinement of the light delivery system can further accelerate the progress of photodynamic medicine. The potential combination of PDT with FGR (to see and to treat) deserves further investigations. If the ideal photosensitizer with good fluorescence yield and high phototoxicity can be successfully developed, it could be used for both diagnosis (PDD) and treatment (PDT).