With the emergence of scarless operations involving the abdominal wall, single-site umbilical LP has also been reported[9-12]. However, single-site umbilical laparoscopy is difficult to perform in newborns and has a high probability of severe complications, such as mucosal perforation and recurrent obstruction. Therefore, a single site umbilical LP has not been greatly reported in recent years. Based on many years of experience with TATSLP, the TUSSLP procedure was developed to overcome many difficulties with transumbilical single-site LP. Here, we present our first 29 cases of HPS who underwent TUSSLP and interpret its technical challenges and solutions.
First, stable fixation and full exposure of the surgical field without instrument collision is a prerequisite for successful TUSSLP. We devised the procedure of transabdominal single-site LP through three incisions made around the umbilical ring. The lack of separation of the camera and instruments limited manoeuvrability in this single-site procedure. In addition, the camera and the two operating forceps parallel to the abdominal cavity could inevitably lead to obstruction of the instruments. Furthermore, the camera in line with the instruments could compromise the intracorporeal visualization of the surgical field. Kozlov et al. suggested that an endoscope longer than the other instruments could help the assistant’s hands out of the operator working space, and the angulation of the optical axis of at least 30° provides an offset, rather than inline, view of the pylorus.
To resolve the problems above, we developed the TUSSLP procedure, in which the LP was performed through two incisions around the umbilical ring, one for a 5 mm trocar and laparoscopy and another for a 3 mm trocar and related single instrument, such as a laparoscopic needle holder, electric hook, pyloric knife, or Maryland forceps. The related laparoscopic instruments may be accessed directly into the perineal cavity through this 3 mm incision. The pyloric canal can be firmly secured and fully exposed by simultaneously tensioning both external thread ends at the left upper quadrant and right lower quadrant of the abdominal wall.
Second, another key to TUSSLP's success is to maintain a clear, bloodless surgical field during the procedure, as well as a large spatial dimension for surgical movements. Due to the traction of external threads on the upper left and lower right quadrants of the abdominal wall, the pyloric tube is lifted forwards. The gap between the abdominal wall and the anterior pyloric tube decreased. By pulling the 5 mm trocar and anchoring umbilical skin upwards to elevate the abdominal wall, the workspace can be expanded. In addition, the incision on pyloric tube with laparoscopic pyloric knife is not recommended because it is too sharp, sometimes will result in the bleeding from the pyloric muscle divided edge. In our experience, the initial cutting on the pyloric tube with a monopolar hook electrocautery, then the pyloric muscle is cleaved with 3 mm Maryland forceps, which could keep the surgical field clean and clear throughout the whole process of TUSSLP.
Third, the length of pyloric muscle separation will determine the effect of LP. The inappropriate length of the incision on the frontier wall of the pyloric canal, whether it is too long or too short, can lead to mucosal damage or incomplete pyloromyotomy[15, 16]. An adequate pyloromyotomy must balance the risk of mucosal perforation and incomplete myotomy, although an inability to palpate the divided pylorus will make the evaluation of these risks particularly challenging. Ostlie et al. suggested that a split length of approximately 2 cm would ensure a complete pyloromyotomy. They also suggested that pyloromyotomy should be longer than the length of the pyloric channel measured by ultrasound. We sought a more objective judgement for a complete myotomy, in which the length of myotomy measured is relatively simple. With the length of the Maryland forceps tip or electric hook tip as a gauge, it is possible to effectively estimate the length of the pyloromyotomy.
Based on the tips above, satisfactory TUSSLP results were achieved in our study. Our findings were consistent with other published series that reported an incidence of incomplete myotomy of 2% to 8%[5, 6, 15] and mucosal perforation of 1.3 to 5.0%[5, 19]. During the follow-up, the overall incidence of vomiting after TUSSLP was not significantly different from that after TATSLP. Nonetheless, the LP procedure does have a learning curve for novices[20-22], especially in the management of TUSSLP, and percutaneous pyloric tube suspension is performed using a needle holder alone without the aid of other instruments. Thus, surgical teaching using simulators for residents or younger consultants is highly advisable, and it could in fact be deemed to be crucial for the safe performance of LP.
Limitations of the current study should be admitted. First, this was a retrospective study. Second, the 10 cases of HPS excluded from the study might reverse the results of the statistical comparison between the 2 groups. Although this study provided standard items for comparison between two procedures, it mostly affected comparison of the cosmetic, which resulted in favor of TUSSLP. Further studies on a larger number of cases may be required for more accurate conclusions.