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principle of Interstitial Laser Photocoagulation of osteoid osteomas

ILP consists of percutaneous insertion of optical fibers into the tumor. The tumor is coagulated and destroyed by direct heating. With a low power laser technique, a well-defined coagulation of predictable size and shape can be obtained in bone tissue. Experimental histopathologic examinations have evaluated the mean diameter of coagulation produced by 805-nm diode laser using 400-┬Ám polymer-clad fiber with a constant power of 2 watts. The mean diameter of coagulation varies from 3.5 mm with 200 joules, 5 mm with 400 joules, 6 mm with 600 joules, 7.5 mm with 800 joules, and 9 mm at 1000 joules in femurs of pigs. The thermal data were significantly higher with lesions of 16 mm in diameter for 1200 joules. We speculated that cellular damage could occur that would be too subtle to detect on histologic examination done imediately after injury. This experimental work has shown that a reproducible area of coagulative necrosis is obtained around the fiber, with good correlation between energy delivered and the lesion size, and with conservation of the biomechanical properties of the bone tissue in the treated area. The size of osteoid osteomas falls within the range that can effectively be coagulated by one or two fibers.

Fig 1: principle


Fig 3: Gross anatomy area of photocoagulation


Fig 4: Histology area of photocoagulation