Abstract
The use of bronchial stapling with automatic stapling devices has become widespread in chest surgery with the growth of video-assisted thoracoscopic surgery. Thus, hand suturing for the bronchus occurs less commonly. Therefore, modern surgeons have fewer opportunities to perform hand suturing, and, as a consequence, there exists lack understanding of this technique compared to earlier generations. We, therefore, examined the difference in bronchial patency between the Sweet and modified Overfolt methods of suturing performed on sacrificed pigs, as shown by bronchoscopy. Bronchoscopy showed stenosis in the residual bronchus using the Sweet method. However, bronchoscopy revealed a favorable patency in the residual bronchus using the modified Overfolt method. We also found similar results in deeper sites. Our findings suggest that the results of the modified Overfolt technique lead to a favorable patency while based on previous knowledge.
Advances in surgical instrumentation have recently been made (1). For instance, most closure of bronchi in chest surgery is carried out using automatic stapling devices (1, 2). Therefore, hand suturing of the bronchus occurs less commonly (2). Furthermore, the widespread use of video-assisted thoracic surgery (VATS) is supported by the frequent use of staplers (1). Even worse, by hierarchy, the most senior surgeon often performs hand suturing due to situations requiring vascular reconstruction of challenging areas in the thoracic field. Therefore, younger surgeons have few opportunities to perform hand sutures, and, as a consequence, there exists lack understanding of this technique compared to earlier generations (3). Thus, given the circumstances, common knowledge on suturing differs significantly between generations. Nevertheless, cases that require hand suturing of the bronchus are occasionally encountered (2). Therefore, in this study we examined the airway patency of the residual bronchus in the lungs of pigs at a bronchial deep site using clear bronchoscopic findings.
Materials and Methods
Animals, experiment and technique. All animals received humane care in accordance with the Japanese Government Animal Protection and Management law. Ex vivo lungs obtained from sacrificed pigs, 6-10 months of age and weighing approximately 100 kg, were used in the present study (4). All procedures were performed by a Board-certified clinical respiratory surgeon (Y.N., Y. I., and H. U.). Each technique was performed once. The Overfolt method was modified to outward membranous areas to maintain the patency (5). Firstly, the left lower bronchus was cut. Next, the Sweet method or the modified Overfolt method was performed with bronchial anastomosis. Bronchial anastomosis was performed using interrupted 4-0 Maxon (Covidien Syneture, Gosport, UK) sutures (eight sutures). Next, the left lower bronchus was cut and two rings were additionally resected to deepen the difference in the bronchial suture between them (Figure 1A and 2A). The anastomosis was treated in a similar manner. The patency of the bronchus was examined by bronchoscopy (BF-F260; Olympus, Tokyo, Japan).
Results
Bronchoscopy showed slight stenosis of the left upper bronchus following the Sweet method (Figure 1B). A similar outcome was observed with different operators/assistants (Figure 1C). However, bronchoscopy revealed favorable patency of the left upper bronchus using the modified Overfolt method, irrespective of the operator or assistant. We also found similar results at the deeper site (Figure 2B and C).
Discussion
Bronchial suturing by hand stitching is clinically important. However, lobectomy using a stapler has become widely accepted due to its ease of use and effectiveness. Tsuchiya et al. reported on the modified Overfolt method, which has a suture line crossing at right angles to the longitudinal axis of the residual bronchial airway, without transformation of the residual bronchus, resulting in a right angle. Tsuchiya et al. speculated that the cartilage of the residual bronchus was deformed and became narrowed postoperatively (5). Arai et al. described that vertical closure of the long axis of the residual bronchus shortened a portion of the bronchus, preventing folding flexion (6). Indeed, information regarding this method of anastomosis is described in a textbook for chest surgery (7). However, it was difficult to distinguish differences in the suture methods existing in the literature due to the lack of clear images. As previously mentioned, the common knowledge of past generations is not the same as that of the current generation.
Our hypothesis was that both methods would lead to the same patency in normal or deep areas because the difference was barely visible at the surface (Figures 1A and 2A). However, the bronchoscopic image differed in several ways. The Sweet method resulted in stenosis in the left upper bronchus, whereas the modified Overfolt method acquired favorable patency. The suture line of the former method ran towards the orifice of the bronchus as a straight line, while those of the latter method turned sideways toward the orifice of the bronchus. Thus, we consider that good patency is precisely maintained using the modified Overfolt method. We also recommend the use of an intraoperative bronchoscope to confirm the patency, especially for a short residual bronchus or following deep wedge lobectomy.
There are several limitations that must be taken into account when considering the present findings. First off, we performed only two experiments. Additionally, the results were not obtained using human bronchus, but rather the trachea of pigs without adjacent tissue and blood flow, and the long-term outcomes were not determined. Nevertheless, the current results highlight an important issue: performing safe surgery is based on the surgeon's ability to remain calm with certain knowledge regarding the cutting process for lung resection. In conclusion, our findings suggest that the results of the modified Overfolt technique not only lead to a favorable patency, but also devolve from previous knowledge.
Footnotes
Conflicts of Interest
None declared.
Disclosure and Funding
No external funding was used in this investigation. None of the investigators received grant money or university funding. All investigators had full control of the study, the methods used, outcome variables, and production of the written report.
- Received March 15, 2016.
- Revision received April 16, 2016.
- Accepted April 20, 2016.
- Copyright© 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved