2.3. Surgical technique of the Sasaki‐W anastomosis (Figure 1, Figure 2, Video S1)

Surgical technique for Sasaki‐W anastomosis (schema). A, Measurement and marking of crushed bowel length. B, Antimesenteric cutback‐incision. C, Supporting thread setup. D, Suturing of the posterior wall with supporting thread. E, Suturing of the anterior wall with supporting thread. F, Completion of anastomosis (upper view). G, Completion of anastomosis (lateral view)

Surgical technique for Sasaki‐W anastomosis (ileo‐ileal anastomosis) (photograph). A, Measurement and marking of crushed bowel length. B, Antimesenteric cutback‐incision. C, Intestine placed in isoperistaltic orientation. D, Supporting thread setup. E, Suturing of the posterior wall with supporting thread. F, Suturing of the anterior wall with supporting thread. G, Completion of anastomosis (upper view). H, Completion of anastomosis (lateral view)

Pean forceps are applied to the proximal and distal intestines where resection is planned. The crushed bowel lengths on the proximal and distal sides are measured. Using a skin marker pen, a marking line is placed on the antimesenteric side of the bowel wall for the length of the other crushed bowel.

After resection of the diseased intestine, the intestinal loops selected for anastomosis are placed in an isoperistaltic orientation. A longitudinal cutback‐incision is created along the marked line at the proximal and distal antimesenteric walls by the electric scalpel. This procedure allows an equal length of the anastomotic line between the proximal and distal sides, allowing for a smooth, wide anastomosis. Because the mucosal surface of the mesenteric side, where ulceration is likely to occur, can be closely observed by this cutback procedure, the presence or absence of retained lesions can be checked.

Supporting threads are placed by seromuscular sutures using 4/0 braided polyglycolide lactide (Vicryl, Johnson & Johnson, New Brunswick, NJ). For posterior wall suturing, supporting threads are applied at three points (mesenteric side of the bowel wall and the termination point of the cutback‐incision (A′ and D, C′ and B in Figures 1C and ​and2D),2D), and both initiation points of the cutback‐incision (Ⓐ and C in Figures 1C and ​and2D)).2D)). With traction of the supporting threads, the operator makes sure that the length of the planned anastomotic line is equal for the anastomosis of the proximal and distal intestines. If the lengths do not match, a further cutback‐incision is added or the supporting thread is applied again to adjust the lengths to match each other.

The anastomosis was created in hand‐sewn fashion in the Albert–Lembert manner (a full‐thickness running suture using double‐ended needle 4/0 polydioxanone (PDS, Johnson & Johnson) and seromuscular interrupted sutures using 4/0 braided polyglycolide lactide). After suturing the posterior wall, a supporting thread is added at one point for anterior wall suture (both initiation points of the cutback‐incision) (A and Ⓒ in Figures 1E and ​and2F).2F). The reasons for choosing a full‐thickness suture are that (a) the anastomotic lumen is not narrowed even when a needle is held firmly with a full‐thickness suture because of its wide anastomotic diameter, and (b) a full‐thickness suture seems to be safe in many cases when the intestinal wall is fragile. In our department, full‐thickness running sutures are performed using 90‐cm double‐ended needle sutures, but 90‐cm sutures may not be sufficient for all circumferential sutures; when necessary, other double‐ended needle sutures are added and sutured circumferentially. The suture is performed with traction of two supporting threads and straightening of the anastomotic line. The mesentery is closed to some extent to prevent internal herniation.

The completed shape of the anastomosis results in a smooth, sufficiently widened diameter. Because the posterior wall at the site of the supporting thread is likely to be convex to the lumen by the traction of the supporting thread, it is adjusted so that it is manually convex to the lateral side.