APA is a very rare disorder and an extremely serious condition in neonates. It is more common in premature infants and is often accompanied by short bowel, multiple atresia, apple-peel configuration and other related malformations, resulting in numerous difficulties during treatment. Furthermore, it has a much higher incidence of post-operative complications and mortality rate than other types of small bowel atresia . The incidence of high jejunal atresia with APA, as reported in this study, is even rarer, and search though the existing English literature revealed only 10 case reports of apple-peel atresia thus far [10–19], with a high mortality rate.
The current accepted treatment option of the APA is resection of the malformed intestinal, but, when apple-peel removal poses a risk of short bowel, part of the apple-peel intestinal tube has to be preserved. However, there is a risk of post-operative volvulus after preservation. There is no report on how the risk of post-operative volvulus can be avoided. The surgical method reported in the literature is end-to-end/-oblique or side-to-side/-oblique anastomosis, and the specific surgical method is not given in detail. Post-operative complications include SBS or bowel failure, intestinal obstruction, which may be caused by excessive bowel resection and lack of good fixation of the mesentery. Three of the surviving cases had feeding difficulties and failure to thrive, which are associated with short bowel syndrome or intestinal failure. We analyzed the reason that the remaining intestinal is too short, or the development of intestinal function is not enough. Lack of good mesoplasty fixation after complete resection of APA may lead to post-operative intestinal obstruction and prolong treatment time. The time of follow-up reported in the literature is variable, and long-term follow-up results are lacking. The cure rate after mesenteric fixation in this group was 86.7%. These groups of patients were followed up for 1 year after the growth and development were good. We consequently summarized the APA case and found that mesenteric fixation is a feasible surgical approach.
There are currently no publications on the surgical treatment of apple-peel atresia for TAPA in particular. Patil et al.  reported on the maturity and importance of end-to-end linear anastomosis in treating different types of intestinal atresia, demonstrating that this technique significantly reduced mortality and post-operative complications. For common APA, the remaining length of the normal intestinal tube is sufficient, and the intestinal malformed bowel can be completely removed without short bowel syndrome after surgery. The remaining intestinal length is less than 60 cm, and it is particularly important to preserve the apple-peel atresia. Preservation of malformed apple-peel atresia length is important, especially in TAPA and PAPA. Fixing the mesentery stabilizes the position of the Intestinal tube and reduces excessive and irregular movement of the intestinal tube after food stimulation. We have summarized the surgical techniques employed in 42 cases of this rare disorder that were admitted to our hospitals over seven years in the present study. The key points to note in pursuit of good post-operative recovery are:
1. The proximal atresia bowel began at the jejunum, the position of the atresia was relatively high, and the position of the proximal jejunum was relatively fixed.
2. Mesoplexy was performed around the atresia blind pouch.
3. Mesoplasty was not performed on the blind pouch, which posed a high risk to the patency of the end-to-side anastomosis to enlarge the blind pouch. The placement of a nasojejunal feeding tube could therefore reduce the risk of anastomotic obstruction.
First, after mesoplasty was performed in this group of patients, the mobility of the enlarged blind pouch was relatively low due to the high position of the proximal atresia. Hence, the volvulus will not occur once the mesentery has been fixed. Fixing the position of the proximal bowel can reduce the traction on the only supplying blood vessel, while preventing the volvulus, incarceration, and necrosis of the distal bowel. Second, due to the high mobility of the distal bowel and the absence of mesentery to fix the bowel loop, the proximal enlarged blind pouch became the preferred choice for fixing the mobilized distal bowel. This can also reduce the traction on the superior mesenteric artery and reduce volvulus, withouth affect the blood supply of the distal bowel. The risk of volvulus and necrosis in the distal bowel was also reduced after feeding. Finally, the placement of a nasojejunal feeding tube enabled the early use of the distal bowel and accelerated the recovery of intestinal function, while also providing good support for the anastomosis and reducing the risk of anastomotic stenosis. Since a patient with APA has an adequate length of distal bowel, partial resection of the affected bowel will not affect the overall bowel length and will not lead to the occurrence of short bowel syndrome.
The advantages of mesopexy were significantly highlighted in the case of total APA. Fixing the only blood vessel supplying the small intestines around the proximal atresia, enlarged and dilated bowel, and reshaping the mesentery not only reduced the irritation on the only blood vessel, but also reduced the mobility of the small intestines. Fixation was performed from the ileocecal region along with the distal enlarged bowel, while fixing the apple-peel atresia small intestines around the lateral wall of the enlarged bowel, which can reduce the formation of bowel incarceration, volvulus, and internal hernia caused by rapid peristalsis. This technique improved the prevention of post-operative complications.
This group of patients exhibited total apple-peel atresia of the distal bowel and had an adequate length of distal small bowel. However, owing to the large disparity in the diameters of the proximal and distal bowels and the presence of an enlarged blind pouch, patients are more prone to food retention and prolonged post-operative enteral and parenteral nutrition. The issue of short-term retention can therefore be solved by the placement of a nasojejunal feeding tube. As the distal bowel gradually developed and widened, the issue of food retention was resolved, and good recovery was also observed in intestinal function during follow-up examinations. For the malformation bowel that can be completely resected in patients with the common type of APA, the tailoring and shaping of the anastomosis are also crucial. The mesentery of the remaining bowel can be developed, but it still needs good fixation and arrangement. When the PAPA malformed bowel needs to be partially preserved, a good fixation of the mesentery can reduce post-operative volvulus. There is a sufficient length of the intestinal tube left to absorb nutrients and avoid the occurrence of short bowel syndrome. Three patients died of severe infection and kidney failure after the surgery. The remaining 39 patients had good post-operative prognoses. It is therefore evident that mesoplasty is critical to the treatment of APA.
There are some limitations to this study. First, a retrospective analysis was conducted in this study, which may have led to limitations in data analysis. Second, our total sample size was relatively low, and more cases are needed for analysis.