Subcostal Specimen Removal in Completely Portal Robotic Lobectomy

The reduction of postoperative pain in patients has been a driving force for surgeons to perform endoscopic operations through small surgical incisions. Some degree of intercostal nerve damage is inevitable because the staplers, thoracoscopic camera, and other instruments are introduced through thoracoports placed in the intercostal spaces. However, utility thoracotomy, which damages the intercostal bundle, causes most of the postoperative pain in patients who receive RAL. Additionally, CO₂ insufflation cannot be used because the utility incision is open to the air of the room. In contrast, the CPRL technique does not require a utility thoracotomy until the end of the procedure, which is the point at which the specimen is removed. CPRL has been sparsely reported in published literature because it is not widely used due to the need for increased robotic console surgeon experience and higher cost compared to RAL.

The most important advantages of CPRL include using an additional posterior fourth robotic arm to allow console surgeons to retract the lung by themselves and using warm CO₂ insufflation to increase the size of the surgical field. The surgeon's assistance in retracting the lung is unnecessary due to the inclusion of the fourth additional robotic arm. Moreover, the use of CO₂ insufflation significantly facilitates pulmonary resection. It extends the intrathoracic view by both lowering the diaphragm and compressing the parenchyma. The CO₂ insufflation air pressure eases hilar dissection and the detachment of pleural adhesions; its heated insufflation reduces the visual interference caused by endoscopic cauterization. In the case of selective tube displacement, the use of CO₂ insufflation protects the surgical workspace by preventing lung inflation; it also has the potential advantages of minimizing postoperative pain and reducing blood loss⁷. Although a higher CO₂ insufflation pressure provides a better view, we did not use it with a pressure exceeding 10 mmHg due to the risk of hypercarbia⁸. CO₂ insufflation can only be used in portal surgical approaches.

The removal of the specimen poses a challenge in CPRL, unlike in RAL, because there is no open incision to extract the resected lobectomy material. According to reported studies, at most centers that perform CPRL, the specimens are removed by enlarging the anterior port to at least 3 cm after the pulmonary resection is complete, and CO₂ insufflation is no longer necessary⁹. Ninan et al.⁴ reported that extraction can be performed through a subcostal trans-diaphragmatic incision without enlarging any ports placed in the ICS. They presented a method for performing robot-assisted pulmonary lobectomy without utility thoracotomy, in combination with the trans-diaphragmatic approach, where they made a subcostal trans-diaphragmatic incision to allow access to the pleural cavity. In our institution, both removal techniques were performed in consecutive patients; we later comparatively analyzed these data to determine whether trans-diaphragmatic removal is necessary.

The removal of the specimen using a subcostal trans-diaphragmatic incision has several advantages. First, it avoids intercostal access thoracotomy and traumatizes only one intercostal neural apparatus. It is well known that intercostal extraction, even without any rib spreading, can cause chronic nerve pain and damage. In this study, postoperative life quality scores were similar, but postoperative pain was significantly less in the subcostal specimen removal group. It can be asserted that almost all group A patients stated that they had localized pain at their utility incision site, whereas the group B patients did not specify any particular port locations, including the subcostal incision. The anterior abdominal wall region has a lax tissue structure unlike that of the ICS, and in our opinion, patients do not experience localized pain in the subcostal port area due to its lax nature.

Second, this technique avoids any restricting bony structures, which may limit the extraction of large tumors. The intercostal space (ICS) is confined by two adjacent costae, which complicates the removal of tumors larger than 4 cm and large-scale specimens. Compression by the ICS may cause specimen distortion, deformation, and endobag damage¹⁰. Furthermore, lung tumors larger than the ICS pose a risk of cancer cell spillage during sample extraction from the thoracic cavity, leading to cancer cell contamination. This risk may increase with larger tumors because the tumor sample within the bag is compressed by the ICS¹¹. In this study, endobag damage was encountered several times in group A. In some cases, lubricant products, such as catagel, were used to facilitate the smooth passage of the endobag through the ICS. In group B, no difficulties in extracting specimens of any size were experienced. The subcostal tissue's lax structure allows the service port region to loosen as the surgeon pushes the extractor out. Moreover, in the absence of CO₂ insufflation, the diaphragm assists in extracting the specimen by pushing the endobag from below. This technique may be the most convenient extraction method, especially for pneumonectomy or bilobectomy specimens.

Nonetheless, the removal of the specimen using a subcostal trans-diaphragmatic incision has some disadvantages as well. First, the thoracic surgeon spends more time than usual during the docking period because of the dissection of the diaphragm. After the surgeon inserts the camera and other ports, the diaphragm is explored with the assistance of CO₂ insufflation. CO₂ insufflation lowers the diaphragm with its air pressure so that the surgeon can explore the diaphragm's attachment to the 10^th rib. After performing endoscopic cautery dissection, the pre-peritoneal plane is divided. A 15 mm subcostal port incision is made at the anterior end of the 11^th rib, which corresponds to the endoscopic diaphragm dissection. While this 15 mm port acts as a service port throughout the operation, we extend it to 3 cm after the pulmonary resection is performed. Subsequently, the subcostal service port acts as an extraction port. In this study, the docking time was significantly greater in group B, whereas there was no significant difference between the groups in terms of operation time.

Second, if the thoracic surgeon is planning to remove the specimen by subcostal trans-diaphragmatic incision, which will act as a service port during the anatomical resection, larger-sized instruments are needed because regular-sized endoscopic instruments are not long enough to perform upper lobectomies. Long roticulated endostaplers, which by the way, increase rotation capabilities, and forceps are necessary for encircling anatomical structures. Nevertheless, they are not mandatory while performing middle or lower lobectomies. In this study, upper lobectomies were not performed using this method without acquiring long endostaplers and forceps.

Postoperative pain was less with subcostal extraction, but potential benefits in terms of pain could also be offset by complications such as diaphragmatic/wound hernias if the integrity of the peritoneum is disrupted while opening the trans-diaphragmatic service port. In this study, such complications were not experienced because the peritoneum was compromised in none of the cases. Additionally, pneumoperitoneum and liver injury may be theoretical complications.

This study had several limitations. Firstly, a limited number of patients were included in both groups due to the single-institution design. Additionally, the study was retrospective in nature. Patients requiring sleeve lobectomy were not offered robotic surgery due to limited capabilities. Since the patient group was limited here, the former patients (cases treated in the early stages of the learning curve) were included in both groups. This would have helped achieve a more precise comparison of operation times.

Ultimately, it can be speculated that performing a subcostal trans-diaphragmatic incision is not a complicated process, though it significantly prolongs the docking time. Although the current experiment is based on a small study group, removing the specimen through the subcostal trans-diaphragmatic incision after CPRL is potentially useful, has several advantages, and is a practical, feasible, and safe method.