Does Single-incision Achieve More Nodes Than Multiple-incision for Thoracoscopic Pulmonary Anatomical Resections
We read with great interest the article by Wang and colleagues 1 about the comparison of single-incision and multiple-incision VATS for pulmonary anatomical resections. A great step in the evolution of VATS was made by the use of a single-incision approach, which was described initially by Rocco and colleagues 2 for minor thoracic and pulmonary procedures. This novel, mini-invasive strategy has been used for both simple and complex pulmonary anatomical resections since 2010. 3 A few initial studies showed optimistic results for single-incision VATS. 3,4 However, no report exists to compare the single-incision approach and the conventional multiple-incision approach until the report of Wang and colleagues, 1 in which they stated that single-incision thoracoscopic pulmonary resection was associated with shorter operative time, higher number of lymph nodes, and less intraoperative blood loss than those with the multiple-incision approach. Some issues are worth noting here.
As we know, a multiple-incision approach should be sufficient to remove the lymph nodes as completely as open thoracotomy, 5 but, in fact, according to the propensity-matched data of Wang and colleagues, the number of lymph nodes retrieved in the single-incision approach was 27.39 ± 12.28, significantly higher than that of the multiple-incision approach, which was about 22.07 ± 11.18; previous data from the Gonzalez-Rivas group 3 showed 14.5 ± 7 lymph nodes dissected by single-incision VATS. Several possibilities could be responsible for the higher number of lymph nodes retrieved during the single-incision approach. The first possibility could be due to heterogeneity between the 2 groups. Although it is a propensity-matched study, the differences were not statistically significant; differences do exist in the characteristics such as operative procedure, tumor location, and pathologic stage. Another reason for more lymph nodes retrieved would be the fragmentation of lymph nodes, because the single-incision approach is more technique demanding than the multiple-incision approach. Three or 4 instruments need to be inserted in the single-incision approach simultaneously; it would inevitably fragmentize the lymph nodes, resulting in more lymph nodes achieved, which does not mean more sufficient or thorough lymph node dissection. The last but not the least explanation was the superiority of the single-port approach; single-incision thoracoscopic technique is based on a completely different geometric concept compared with conventional 3-port VATS. 6 In fact, the approach to the target lesion in the lung is substantially similar to the approach that a surgeon would use in open surgery, therefore resulting in more lymph nodes dissected during a single-incision approach. 7
Wang and colleagues found no difference in postoperative complications between the single-incision and multiple-incision groups. Unfortunately, the postoperative pain score was not recorded. 1 Theoretically, because the single-incision technique, which avoids the inferior incision and inserts the camera and the instruments thorough the utility incision, would be less invasive than the multiple ones, the short-term postoperative outcomes including morbidity and pain would be improved. However, the standard single-incision approach is associated with potential disadvantages; the camera competes with the operative instruments, and the chest tube needs to be incorporated within the 4- to 6-cm access incision. 5 Limited studies reported on the comparison of short-term postoperative outcomes between the 2 different VATS approaches. 8 We expect a prospective randomized study to confirm the advantages of single-incision approach over the traditional established multiple-incision approach.
Three innovations have potential value to simplify the single-incision approach. One is a new, modified, single-incision approach creating a small incision adjacent to the access incision.