Four piglets were used, see Table 1 for abdominal dimensions and distances between the operative ports. Relevant external or internal instrument - instrument collisions were detected with a median rate of two per procedure. All could be resolved by repositioning of the robotic arms. No relevant instrument - organ collisions occurred.
Pivot point calibration for laparoscopy and thoracoscopy
Calibration for the pivot point was successful in most of the procedures, 0.5% of cases needed two attempts. Bending of the instruments was not encountered, neither during calibration of the pivot point nor during the procedures.[11]
Explorative laparoscopy
Inspection and evaluation of the four abdominal quadrants was performed by a three port approach with two instruments. We managed to accomplish handling of and running the bowel. It was possible to change the work space from one quadrant to that which was horizontally adjacent without manually repositioning the ports. By contrast, changing work spaces and quadrants in a vertical manner required manual repositioning of the camera and the robotic arms.
Abdominal wall reconstruction
After explorative laparoscopy, the abdominal wall was incised in the left upper quadrant and the musculature and peritoneum then sutured by interrupted and running sutures (Vicryl 3 − 0 RB-1, Ethicon, Johnson and Johnson, Germany) simulating abdominal wall hernia repairs.
Suture Ligation of the umbilical vein
The piglet was placed in the anti Trendelenburg position, the camera port was placed 3 cm below the umbilicus and the left and right robotic arm were placed in triangulation to the umbilical vein.
The umbilical vein was fixed with a grasper in the left arm and dissected from the abdominal wall and towards its entry into the liver. Upon complete mobilization it was suture ligated on both ends (Vicryl 5 − 0 TF-1, Ethicon, Johnson and Johnson, Germany) and then transsected. The resected part was extracted from the abdomen through the right hand port.
Vesicocutaneostomy
The piglet was placed in the Trendelenburg position, the camera port was placed in the umbilicus and the left and right 3 mm robotic arm was in triangulation to the dome of the bladder. The dome of the bladder was identified and opened with monopolar hook cautery. The opening was sutured to a corresponding incision in the abdominal wall with interrupted 10 cm 3 − 0 Vicryl SH sutures. Then, the sutures of the cystocutaneostomy were taken down and the defect in the bladder was closed with interrupted 10 cm 3 − 0 Vicryl SH sutures.
Nephroureterectomy (one (left) in the live animal and two (each one right and left) in the euthanized animal)
The piglet was placed in an almost prone to 20° dorsally rotated position. Access to the right kidney was gained with the camera port which was inserted 2 cm to the right of the umbilicus, the left and right arm were positioned in triangulation to the right kidney. An additional port for retraction of the bowel was inserted caudally to the left arm port.
After visualization of the right kidney, the afferent and efferent vessels and the ureter were isolated. The vessels were separated under 5 − 0 Vicryl ligatures. After vascular control the kidney was mobilized, the ureter suture ligated (5 − 0 Vicryl) and cut next to its entry into the bladder. The kidney was not extracted through an incision to the outside of the abdominal cavity but placed into the pelvis, as multiple procedures were performed in those piglets.
In the euthanized animal the same set up and approach was used as for the pyeloplasties below: Initial dissection was performed with a fenestrated atraumatic grasper in the left hand and bipolar forceps on the right. The renal hilar vessels were each identified, dissected, controlled and cauterized using the bipolar forceps, then divided using the curved scissor instrument. Attention was then turned to the rest of the kidney, which was dissected out, again using the fenestrated grasper in the left hand and bipolar forceps in the right, starting working cranially then caudally until fully free. The ureter was then divided using the curved scissors ready for the specimen to be removed.
Pyeloplasty (one on a left kidney in a live animal and one left- and one right-sided pyeloplasty in an euthanized animal each)
For the procedure in the live animal, the piglet was placed in an almost prone to 20° dorsally rotated position. Access to the left kidney was gained with the camera port inserted 2 cm to the right of the umbilicus, the left and right arm were positioned in triangulation to the left kidney. An additional port for retraction of the bowel was inserted caudally to the left arm port. The kidney was exposed, the vessels identified and marked with loops (Vicryl 3 − 0). The renal pelvis was isolated and cut longitudinally. Transverse reconstruction was done with interrupted 5 − 0 Vicryl TF-1 sutures.
For the procedures in the euthanized animal, in a lateral position with the ipsilateral side up, three modular robotic bases (camera and two operating modules) were positioned on the contralateral side of the operating table. Following insertion of the umbilical port using standard cutdown technique, the location of the kidney was identified to then allow careful triangulation of two 5mm ports which were inserted under vision. No additional ports were required. Initial dissection was performed with a fenestrated atraumatic grasper in the left hand and bipolar forceps in the right. Once the pyeloureteric junction was carefully delineated, in the absence of intrinsic obstruction, an incision was made extending from mid-pelvis a considerable way down the ureter using a curved scissor instrument to simulate the normal spatulation of the ureter. An anastomosis was then completed with 5 − 0 Vicryl in one case and 6 − 0 PDS in the other, using two needleholders.
Entero-enterostomies
The camera port was placed in the umbilicus, the left and right arm port in triangulation to the gastric greater curvature. Two loops of small intestine were placed next to each other, incised longitudinally with monopolar hook cautery, and anastomosed with an interrupted or running suture each (5 − 0 Vicryl TF-1, 10 cm)
Gastric wedge resection
The camera port was placed in the umbilicus, the left and right arm port in triangulation to the gastric greater curvature. The greater curvature was dissected and a wedge resected applying a laparoscopic stapler (Just Right, Hologic, USA) via an assistant port.
Atypical liver wedge resection
The camera port was placed in the umbilicus, the left and right arm in triangulation to the left lobes of the liver. The piglets' livers were extremely vulnerable to grasping and retraction. The most peripheral lobe was visualized and an atypical wedge resection of a representative part of the liver was resected with monopolar and bipolar hemostasis. We did not encounter any bleedings or bile leakage during follow-up while operating on other abdominal organs.
Splenectomy
The camera port was placed in the umbilicus, the left and right arm in triangulation to the spleen. The surrounding tissue was dissected from the splenic hilum and the hilar vessels transsected applying a laparoscopic stapler (Just Right, Hologic, USA) via an assistant port.
Diaphragmatic plication and closure of a diaphragmatic hernia
The piglet was placed in anti-Trendelenburg’s position. The liver was retracted by a 5mm blunt grasper inserted through an additional port in the left upper quadrant. The camera port was placed in the umbilicus, the left and right hand port were placed in triangulation to the esophagus. The left diaphragm was exposed and incised horizontally in the lumbocostal region to simulate a Bochdalek diaphragmatic defect. The defect was then closed with interrupted sutures (Ethibond 2 − 0). Over the closed defect, the diaphragm was plicated in a vertical mattress fashion with interrupted 2 − 0 Ethibond slipping knots.
Nissen fundoplication and hiatoplasty
The piglet was placed in anti-Trendelenburg position. The liver was retracted by a third robotic instrument inserted through an additional port in the left upper quadrant. The camera port was replaced from the umbilicus to a position 3 cm in the midline above the umbilicus for better access to the subdiaphragmatic region, the left and right hand port were placed in triangulation to the esophagus.
After visualization and dissection of the esophagus, the fundus was mobilized with bipolar cautery. Access to the hiatus was obstructed by the vulnerable liver, careful retraction and dissection exposed the hiatus, which resulted in opening the right hemithroax. Hiatoplasty was performed by interrupted 3 − 0 Vicryl sutures. A gastric 360° Nissen wrap was placed around the esophagus and stitched with interrupted sutures (3 − 0 Vicryl S-H, Ethibond, Germany).
Cholecystectomy
The piglet was placed into anti-Trendeleburg’s position and turned slightly to its left side. The three robotic ports were placed with triangulation into the area of the gallbladder with the camera port in the umbilicus. The liver was elevated by applying a third robotic instrument port and a long grasper. The neonatal piglet liver, as well as the gallbladder, is very sensitive to mechanical stress as reported earlier.[11] After elevation of the liver and retraction of the gallbladder the infundibulum, the cystic duct and the cystic artery were identified. Ligation of the cystic artery and duct was accomplished with 5 − 0 Vicryl RB-1 (Ethicon, Germany). Gallbladder dissection from the liver was performed with monopolar hook cautery.
Cholecystoenterostomy
The piglet was placed into anti-Trendeleburg position and turned to its left side. The three robotic ports were placed with triangulation into the direction of the gallbladder with the camera port in the umbilicus. Due to the anatomy of the porcine liver, a fourth port was needed in the left upper abdomen for robotic liver retraction. A 2 mm incision was set in the fundus of the gallbladder with monopolar hook cautery. An adjacent loop of small bowel was opened longitudinally with cautery to a corresponding length. The omega shaped anastomosis was performed with interrupted sutures, the dorsal knots pointing to the inside, the ventral ones to the outside (6 − 0 Vicryl TF-1, Ethicon,Germany).
Esophageal resection and anastomosis
Before commencing the procedure, the piglet had to be euthanized as it was suffering from pneumonitis. The procedure was then performed on the euthanized piglet: Access to the right thorax was gained with the lung compressed by insufflation of CO2 with a pressure starting with 4 mmHg. The piglet was ventilated bilaterally and placed almost prone, the camera port was placed about 2 cm para-spinally to the right in extension of the right eye in the mid thoracic height. The ports for the left and right instruments were placed cranially and caudally to the camera port and more anterior situated. Access to the porcine thorax was possible, although the narrow intercostal spaces hampered manipulation, especially with respect to the 10 mm camera.
The esophagus was isolated while sparing the vagal nerve. An approximately 8mm long segment was resected and the ends anastomosed end to end with interrupted Vicryl 5 − 0 TF-1 suture.
Lobectomy of the right upper lobe
The piglet was placed in near-prone position, the camera port was placed about 5 cm paraspinally to the right at mid thoracic height. The ports for the left and right instruments were placed cranially and caudally to the camera port and more posteriorly situated for triangulation to the lung. For retraction, an additional port was placed caudally to the left arm port.
The thorax was insufflated with CO2 and the piglet was ventilated on both lungs. The right upper lobe, the vessels and the bronchus were identified. The bronchus was cut between ligatures, the vessels were divided between ligatures (5 − 0 Vicryl TF-1). The upper lobe was then completely mobilized but not extracted.
Complications and technical limitations
We did not encounter any surgical or robot associated complications during the study. The minimum insertion depth of at least 2 cm, which was required for successful pivot point calculation, did not lead to any complications. One animal had to be euthanized due to intractable pneumonia which aggravated before the thoracic procedures.