Untersuchungen zur initialen Luftdichtigkeit nach nicht anatomischen Lungenparenchymresektionen durch Thulium Laserfasern unterschiedlicher Dicke

Background: Lung metastases can be resected non-anatomically by use of a Laser. The Laser produces a sealing coagulation layer on the resected lung surface. It is yet not clear if the resected lung surface should additionally be sutured for airtightness. Without the use of a suture, the lung tissue would be less restricted after surgery, leading to an improved expansion and healing of the lung. Methods: With a Thulium Laser Vela® QI non-anatomical lung parenchyma resections of three different depths (0.5 cm, 1.0 cm, 2.0 cm) were performed on paracardial pulmonary lobes of a pig. Each resection was performed with three different Laser fibers (230 μm, 365 μm, 600 μm) and at two different output powers (10 W, 30 W). The pulmonary lobes were then connected to a ventilation tube and ventilated via a respirator (flow: 20 l/min, PEEP: 5 mbar, Pinsp: 15 mbar). The resected surface was tested for airtightness and by increasing the inspiratory pressure the burst pressure of the resected lung surfaces was determined. All resected lung surfaces were examined histologically and the thickness of the coagulation zone was determined. Results: The resected lung surfaces were all 100% airtight when using the 600 μm Laser fiber and an output power of 10 or 30 W. An overall initial airtightness was not observed when using the 230 μm or 365 μm Laser fibers. Air leakages were mainly caused by the openings of segmental bronchi in the resected lung surface. The mean burst pressure was the highest using the 600 μm Laser fiber and either output power compared to the other two fibers. The mean burst pressure with the 600 μm fiber and an output power of 30 W was 41.6 ± 3.2 mbar (0.5 cm) and 33.7 ± 4.8 mbar (2.0 cm). The mean thickness of the coagulated layer was greatest using the 600 μm fiber as well (315.5 ± 6.4 μm at 30 W). Conclusion: Lung resections by the Thulium Laser (600 μm fiber, 30 W) might not be additionally sutured since the resected surfaces are initially airtight and the burst pressures of the surfaces are sufficient. Nevertheless, injured segmental bronchi in the resected surfaces should be identified and closed by a suture. These experimental data as well as the permanent airtightness of the resected surfaces after a resection by a Thulium Laser should be confirmed in further experimental and clinical studies.