Number of Retrieved Lymph Nodes and Postoperative Pain in Single-incision and Multiple-incision Thoracoscopic Surgery
We thank Bao et al for their interest 1 in our article. 2 There are many controversies with regard to lymph node dissection both for staging and therapeutic purposes. The decision to perform a radical lymph node dissection or a lobe-specific lymph node dissection depends on clinical stage, different practice guidelines, aggressiveness of the surgeon, and also the dedication of the pathologist to separate and analyze the specimens.
The greatest limitation of our study has been the different time periods in which the surgical procedures were carried out in the 2 groups. We have practiced multiport thoracoscopic technique since 2005. Using the 2- or 3-port technique allowed us to perform procedures including radical mediastinal lymph node dissection efficiently and radically (http://youtu.be/3Wm5Sp10GRI); we also started performing single-port thoracoscopic anatomic lung resection in 2010. According to the concept of oncological radicality, mediastinal lymph node dissection should not be compromised in any different approaches. We believe that the single-port technique is basically an alternate form of thoracoscopic surgery, with the advantage of avoiding the side view from the camera inserted through a lower intercostal space, and regaining the “baseball-diamond” instrument setting for the operator to perform dissection, despite the possibility of internal and external instruments fighting. To reduce the interference caused by instruments fighting and perform radical dissection in single-port surgery, we modified our setting including surgical instruments and developed a specific maneuver (http://youtu.be/LBz08AyWoRs) to harvest mediastinal lymph nodes. These specific modifications have been described previously, 3 and videos with regard to our techniques are available online (http://youtu.be/kdtuWTWOYNQ). Although fragmentation of the lymph nodes is sometimes difficult to avoid, we prefer to remove all the lymph nodes of the same station in an en bloc manner.
Pain study is even more challenging and controversial. 4,5 We retrospectively reviewed our database and medical records for patients enrolled in the previous study, 2 and only the 35 paired patients who underwent lobectomy were enrolled for pain study (Table 1). Parameters included objective pain scores, pain medications, perioperative spirometer data, surgical procedure (single- vs multiple-incision), length of wound, length and volume of the tumor, volume of the lung specimen containing the tumor, size of the chest tube placed, and location of the lobe removed (Table 2). Note that most of the procedures in the multiport groups (33/35, 94.3%) were carried out by the 2-port technique. Although the length of wound and the size of chest tube were both smaller in the single-port group, we still failed to demonstrate that single-port surgery reduces postoperative pain significantly, even using a generalized estimating equation model for a repeated-measure pain score analysis; one possible reason might be the relatively small sample size for this pain study.
Therefore, different approaches should be considered as alternative ways to solve this problem. With advances in cancer screening, the number of patients with early stage lung cancer visiting our clinic is increasing. Thanks to the rapid progress in instruments and techniques, we are now able to perform anatomic lung resection without torqueing the intercostal nerve, especially the sensitive area near the breast— the subxiphoid single-incision thoracoscopic approach 6 —(http://www.ctsnet.org/article/subxiphoid-single-incision-lung-resection), although it is a new technique presenting with limitations, it still deserves further investigation.
We thank Dr Enrico Melis for his kind help with English editing.