Rapid sealing of porcine renal blood vessels, ex vivo, using a high power, 1470-nm laser, and laparoscopic prototype

Abstract

Energy-based, radiofrequency (RF) and ultrasonic (US) devices currently provide rapid sealing of blood vessels during laparoscopic procedures. We are exploring infrared lasers as an alternate energy modality for vessel sealing, capable of generating less collateral thermal damage. Previous studies demonstrated feasibility of sealing vessels in an in vivo porcine model using a 1470-nm laser. However, the initial prototype was designed for testing in open surgery and featured tissue clasping and light delivery mechanisms incompatible with laparoscopic surgery. In this study, a laparoscopic prototype similar to devices currently in surgical use was developed, and performance tests were conducted on porcine renal blood vessels, ex vivo. The 5-mm outer-diameter laparoscopic prototype featured a traditional Maryland jaw configuration that enables tissue manipulation and blunt dissection. Laser energy was delivered through a 550 - ? m -core-diameter optical fiber with side-delivery from the lower jaw and beam dimensions of 18 - mm ? length × 1.2 - mm ? width . The 1470-nm diode laser delivered 68 W with 3-s activation time, consistent with vessel seal times associated with RF and US-based devices. A total of 69 fresh porcine renal vessels with mean diameter of 3.3 ± 1.7 ?? mm were tested, ex vivo. Vessels smaller than 5-mm diameter were consistently sealed (48/51) with burst pressures greater than malignant hypertension blood pressure (180 mmHg), averaging 1038 ± 474 ?? mmHg . Vessels larger than 5 mm were not consistently sealed (6/18), yielding burst pressures of only 174 ± 221 ?? mmHg . Seal width, thermal damage zone, and thermal spread averaged 1.7 ± 0.8 , 3.4 ± 0.7 , and 1.0 ±

Doppler optical coherence tomography for energy seal evaluation and comparison to visual evaluation

“…Given this, it is paramount to have an objective method with which vessel seals can be evaluated so that the hemostatic capabilities of laser-based systems can be tested. Current methodologies used for this purpose include burst pressure analysis (BPA), [9][10][11] microscopy, 12 and visual examination. [13][14][15][16] While BPA yields valuable insight as to the strength of seals, it cannot be performed in situ without invasive measures.…”

The dual 980‐nm and 1470‐nm diode laser for vascular lesions

“…12 With the 1470-nm near-infrared wavelength vessels of diameter ≤5 mm can also be permanently sealed. 13 Maximum temperature inside a laser-irradiated blood vessel is a critical characteristic of the vessel heating process. It is dependent on laser beam power, wavelength, diameter, and depth of the vessel in the skin.…”

“…The 1470‐nm laser wavelength is absorbed by water 12 . With the 1470‐nm near‐infrared wavelength vessels of diameter ≤5 mm can also be permanently sealed 13 …”

Optical Coherence Tomography for the Evaluation of Energy Seals and the Subsequent Evaluation of the Thulium Laser as a Hemostatic Instrument

“…Given this, it is paramount to have an objective method with which vessel seals can be evaluated so that the hemostatic capabilities of laser-based systems can be tested. Current methodologies used for this purpose include burst pressure analysis (BPA) [94][95][96], microscopy [47], and visual examination [97][98][99][100]. While BPA yields valuable insight as to the strength of seals, it cannot be performed in situ without invasive measures.…”