Background: rigid trocars are widely adopted in video-assisted thoracic surgery (VATS), despite some disadvantages: (I) cannula strong pressure on intercostal nerve stimulating postoperative pain; (II) limited movement of thoracoscopic devices on their fulcrum when extreme acute angles with the chest wall are needed. Wound retractor (WR) device, designed for laparoscopic surgery, it is also used in VATS, but to protect mini-thoracotomy. We compared the use of extra-small WR versus rigid trocar at camera port that is the most painful thoracostomy. The aim was to determine if WR is associated with less postoperative pain and better scope maneuverability.
Methods: This is a single institution prospective study recorded and approved by ethics committee at our hospital. From October 2016 to June 2017, we enrolled 40 patients (statistical power 88%), randomized into two different groups. Group A (20 patients) underwent VATS lung resection using WR at camera port, group B (20 patients) using rigid trocar. Intra-operative data collected were maximum acute angle obtained between the camera and chest wall and chest wall thickness. Pain was measured by numerical analog scales (NAS) at 6, 12, 24, 48 and 72 hours after surgery. We also measured total morphine consumption at 72 h administered by patient controlled analgesia (PCA) system.
Results: No statistical significance was found in the demographic traits of the two groups (P=1). Statistically significant differences were found in favor of group A for both pain control, morphine consumption (P<0.001) and camera maneuverability (described as maximum acute angle obtained/chest wall thickness) (P<0.001).
Conclusions: patients who had WR showed less postoperative pain. Moreover, WR presented other advantages: camera protection by small bleeding from chest wall, adaptability with every chest wall thickness, absence of skin injury around the port. We suggest its use instead of rigid trocar.