Abstract. Suture ligation with subsequent cutting of blood vessels to maintain hemostasis during surgery is time consuming and skill intensive. Energy-based electrosurgical and ultrasonic devices are often used to replace sutures and mechanical clips to provide rapid hemostasis and decrease surgery time. Some of these devices may create undesirably large collateral zones of thermal damage and tissue necrosis, or require separate mechanical blades for cutting. Infrared lasers are currently being explored as alternative energy sources for vessel sealing applications. In a previous study, a 1470-nm laser was used to seal vessels 1 to 6 mm in diameter in 5 s, yielding burst pressures of ∼500 mmHg. The purpose of this study was to provide vessel sealing times comparable with current energy-based devices, incorporate transection of sealed vessels, and demonstrate high vessel burst pressures to provide a safety margin for future clinical use. A 110-W, 1470-nm laser beam was transmitted through a fiber and beam shaping optics, producing a 90-W linear beam 3.0 by 9.5 mm for sealing (400 W∕cm 2 ), and 1.1 by 9.6 mm for cutting (1080 W∕cm 2 ). A two-step process sealed and then transected ex vivo porcine renal vessels (1.5 to 8.5 mm diameter) in a bench top setup. Seal and cut times were 1.0 s each. A burst pressure system measured seal strength, and histologic measurements of lateral thermal spread were also recorded. All blood vessels tested (n ¼ 55 seal samples) were sealed and cut, with total irradiation times of 2.0 s and mean burst pressures of 1305 AE 783 mmHg. Additional unburst vessels were processed for histological analysis, showing a lateral thermal spread of 0.94 AE 0.48 mm (n ¼ 14 seal samples). This study demonstrated that an optical-based system is capable of precisely sealing and cutting a wide range of porcine renal vessel sizes and, with further development, may provide an alternative to radiofrequency-and ultrasonic-based vessel sealing devices.

Identification and preservation of the cavernous nerves (CNs) during prostate cancer surgery is critical for postoperative sexual function. Electrical nerve stimulation (ENS) mapping has previously been tested as an intraoperative tool for CN identification, but was found to be unreliable. ENS is limited by the need for electrodetissue contact, poor spatial precision from electrical current spreading, and stimulation artifacts interfering with detection. Alternatively, optical nerve stimulation (ONS) provides noncontact stimulation, improved spatial selectivity, and elimination of stimulation artifacts. This study compares ENS to pulsed/CW ONS to explore the ONS mechanism. A total of eighty stimulations were performed in 5 rats, in vivo. ENS (4 V, 5 ms, 10 Hz) was compared to ONS using a pulsed diode laser nerve stimulator (1873 nm, 5 ms, 10 Hz) or CW diode laser nerve stimulator (1455 nm). Intracavernous pressure (ICP) response and nerve compound action potentials (nCAPs) were measured. All three stimulation modes (ENS, ONS-CW, ONS-P) produced comparable ICP magnitudes. However, ENS demonstrated more rapid ICP response times and well defined nCAPs compared to unmeasurable nCAPs for ONS. Further experiments measuring single action potentials during ENS and ONS are warranted to further understand differences in the ENS and ONS mechanisms.

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