OBJECTIVE: To assess cautery instruments used in robotic assisted laparoscopic (RAL) surgery in regard to critical heat spread on tissue and cellular level.
MATERIALS AND METHODS: Thermal spread along bovine musculofascial tissues was examined by infrared camera, histology and enzyme assay. Currently used monopolar, bipolar and ultrasonic laparoscopic instruments were investigated at various power settings and application times. The efficacy of using an additional Maryland clamp as a heat sink was evaluated. 45°C was considered the cutoff temperature for possible nerve damage.
RESULTS: Monopolar instruments exhibited a critical spread of 3.5 ± 2.3 mm when applied at 60 W for 1 s. After 2 s, the spread surpassed 20 mm. For adjustable bipolar instruments the spread was 2.2 ± 0.6 mm at 60 W and 1 s and 3.6 ± 1.3 mm at 2 s. PK and LigaSure forceps had spreads of 3.9 ± 0.8 mm and 2.8 ± 0.6 mm respectively, whereas the ultrasonic instrument reached 2.9 ± 0.8 mm. Application of an additional Maryland clamp as a heat sink significantly reduced the thermal spread. Histomorphometric analyses and enzyme assay supported these findings.
CONCLUSION: All coagulation devices used in robotic assisted laparoscopy surgery have distinct thermal spreads depending on power setting and application time Cautery may be of concern due to lateral temperature spread, causing potential damage to sensitive structures including nerves. Our results provide surgeons with a resource for educated decision making when using coagulation devices during robotic procedures.