The first use of uniportal VATS for pulmonary nodule biopsy was reported in 2004 by Rocco (1). With technological advancement in recent years, the scope of application of uniportal VATS has gradually expanded. Since then, the first lobectomy using uniportal VATS was reported in 2011 by Gonzalez-Rivas (8). Subsequently, the uniportal VATS approach has been comprehensively developed and applied for lobectomy and segmentectomy. Increasing numbers of reports have confirmed that uniportal VATS is effective in reducing postoperative incision pain and paresthesias in patients, with equal outcomes compared to multi-port thoracoscopy and open thoracotomy (1–3, 9–11). Uniportal VATS has been widely used in various kinds of thoracoscopic pulmonary surgery throughout many institutions and has replaced most multi-port thoracoscopic surgery (12–13).
Some intraoperative complications can lead to the conversion from uniportal VATS to multi-port VATS or open thoracotomy, which can lead to increased morbidity, increased surgical time and length of hospital stay (14–15). Common reasons for conversion include pleural adhesions, aggressive tumor or lymph node invasion, requirement for bronchoplasty or other special surgical methods, pre-operative ventilatory failure, and pulmonary hemorrhage. Pulmonary artery hemorrhage is a dangerous intraoperative complication that is difficult to correct, making it one of the most significant challenges for thoracoscopic lobectomy (16–19).
Pulmonary artery hemorrhage is more likely to occur and more difficult to manage if it occurs in the uniportal VATS approach compared to open thoracotomy. In addition to the pulmonary artery’s increased susceptibility to injury due to its large size, there are several reasons for the increased risk of pulmonary artery hemorrhage in uniportal VATS. The uniportal VATS approach has a limited operating plane with less stereoscopic vision than in multi-port thoracoscopy and open thoracotomy. In addition, the electrocoagulation hook lacks effective haptic feedback, making control of depth and force difficult in the process of pulmonary artery separation. Also, visualization of the surgical field in uniportal VATS is more susceptible to occlusion by lung tissue and instrumentation.
These factors contribute to the increased risk of pulmonary artery bleeding during uniportal VATS, which may lead to unplanned conversion to open thoracotomy. Yet, if the pulmonary artery can be directly repaired in the uniportal VATS approach, conversion to a more invasive surgical approach may not be necessary. However, the actual operation is very difficult for several reasons. Firstly, in the uniportal VATS approach, especially the small ≤ 3 cm incision uniportal VATS carried out by our department, the incision size greatly limited the ability to quickly insert the auricle clamps and clamp the pulmonary artery. In addition, the bleeding results in the blurring of the plane field of vision which was already relatively limited. Secondly, even after adjusting the position of the forceps, there is generally extremely limited space for instrumentation for pulmonary artery repair, thus prolonging operation time and frequently leading to an increase in operation incisions or a conversion to open thoracotomy. Thirdly, the duration of time needed to suture the PA in the thoracoscopic approach exceeds the 30 minutes limitation on the duration of pulmonary artery clamping, which may lead to ischemia reperfusion injury, pulmonary edema, and other adverse events.
In the event of pulmonary artery bleeding, uniportal VATS lobectomy requires adequate time and space for instrumentation for pulmonary artery repair, rapid occlusion of the artery in order to keep the field of vision as clear as possible, and prevention of serious pulmonary artery hemorrhage. Besides constantly improving surgeon skill and experience, there remains a need for pulmonary artery clamping techniques that are more suitable for uniportal VATS. Thus, we have developed this preventive pulmonary artery clamping technique, with clear advantages for uniportal VATS. This clamping technique occupies very minimal space with simple instrumentation (8–10), providing sufficient operating space for pulmonary artery repair and minimizes instrumentation interference. In addition, preventive clamping can reduce pulmonary artery pressure, which may facilitate lymph node dissection—for lymph nodes or tumors with severe adhesions to blood vessels, pulmonary artery clamping can facilitate a difficult dissection. Also, the reduced tension in the distal pulmonary artery greatly lowers the risk of pulmonary artery rupture during dissection. Even if the pulmonary artery ruptures during dissection, no major bleeding will occur, and the repair can be unhurried. Moreover, preventive pulmonary artery clamping rapidly and effectively reduces bleeding, ensures a clear operating field, avoids accidental injury, and makes uniportal VATS easier to perform. The preventive pulmonary artery clamping technique is also relatively accessible for widespread implementation because it is easy to learn and perform and requires simple and common materials and skills.
According to our institution’s experience, in uniportal VATS, the preventative pulmonary artery blocking technique significantly reduced the operation conversion rate, blood loss and blood transfusion volume, and duration of pulmonary artery repair.
We propose several suggestions for the implementation of this technique:
- This method is more suitable for cases at high risk for bleeding, such as tumor or lymph node adhesion to blood vessels. In conventional patients, pretreatment PA clamping may increase operation time and risk.
- The surgeon must be skilled in thoracoscopic surgery, especially in the dissection of the pulmonary artery and vascular repair in the event that it becomes necessary.
- Pretreatment PA clamping is more suitable for uniportal VATS, especially conferring more obvious advantages in small incision uniportal VATS, though the technique can certainly also be applied to multi-portal thoracoscopy and open thoracotomy.
In addition, our department has adhered to a “lymph node dissection first, pulmonary lobectomy later” protocol for about a decade whether for open thoracotomy or uniportal VATS (4, 5). This protocol has several advantages: thorough dissection of the pulmonary hilum makes the blood vessels well-exposed and easy to manipulate. Also, if bleeding occurs, it is easier to get better visual field of operation through pulmonary lobes tugging. Additionally, pulmonary artery repair is easier without view obstruction by lymph nodes. Procedural operation is also easy to learn, which helps to shorten the learning curve for the uniportal VATS approach (5).
In conclusion, this preventive pulmonary artery clamping technique maintains space for instrumentation and provides effective occlusion of the PA. The technique is especially suitable for small (≤ 3 cm) single-incision thoracoscopic surgery in order to reduce the operation conversion rate caused by pulmonary artery hemorrhage. Due to a limited number of cases, more experience is needed before further promotion and application. However, preventive pulmonary artery clamping has the potential to make small-incision uniportal VATS procedures safer and smoother for patients.