In laparoscopic surgery, smaller abdominal adjuvant incisions can offer both cosmetic advantages and important clinical implications, such as less postoperative pain, shorter hospital stay and faster return to daily activities. However, no relevant research has Study Indicated the relationship between the abdominal wall stoma, the extension of the incision and the specimen diameter. The method for extracting the specimen depends on the surgeon’s experience and personal preference. Moreover, regardless of the shape and size of the incision, several aspects should be considered: (1) small injury, (2) good cosmetic effect, (3) malignant tumour specimens that can be removed intact, (4) taking into consideration the urinary flow diversion and (5) less complications of adjuvant incision.
In this paper, we discuss for the first time the relationship between the abdominal wall stoma, the extension of the incision and the specimen diameter by simulating postoperative specimen retrieval through in vitro physical experiments, which significance is to guide the clinic to choose the shape and size of the incision based on the diameter of the specimen measured by preoperative imaging combined with the needs of the operation and the position of the trocar.
Ileostomy is widely used in the treatment of muscle-invasive bladder cancer in urological surgery. Its surgical specimens include the prostate and the bladder. The diameter of the ileum is about 3.0 cm [6], and the recommended diameter of the dermal stoma is 3.0 cm [7]. Thus, the diameter of the stoma should be between 3.0 ± 0.3 cm. Combined with the results of this experiment, the ileum abdominal wall stoma can be used to extract a specimen with a diameter of about 4.5–6.0 cm (Figure. 3). In clinical practice, we have attempted to extract laparoscopic specimens (prostate and bladder) from the abdominal wall stoma of patients undergoing complete laparoscopic radical cystectomy and ileostomy and verify that the extraction method is feasible.
In our experimental design, the shape of inverted Y incision is mainly used for the extraction specimens from around the umbilicus. In clinical practice, many transabdominal laparoscopy trocar ports are located around the umbilicus, including laparoscopic hepatectomy, splenectomy and resection of other large abdominal tumours. The results of the experiment showed that specimens with diameters of 6.0, 8.0 and 10.0 cm can be extracted using inverted Y-shaped incisions with the length around umbilicus of 1 cm and extension length of 1.0, 3.0 and 4.0 cm and with the length around umbilicus of 2 cm and extension length of 0.0, 1.0 and 2.0 cm, respectively. Thus, this incision compensates for the shortcomings of the study by Casciola et al. to some extent [4]. We have also attempted to extract laparoscopic radical prostatectomy specimens by enlarging the trocar port of the superior umbilicus into an inverted Y shape in clinical practice, and the results are consistent with the present findings. (Figure. 4)
Extending the trocar port as an auxiliary incision for specimen retrieval is the most common method of specimen extraction for most laparoscopic procedures. In tough tissue specimens (e.g., renal tumours, adrenal tumours and other tumours of the abdominal cavity), incisions with length of 1.0, 2.0, 3.0 and 4.0 cm could be used to extract specimens with maximum diameters of 1.0, 2.0, 4.0 and 6.0 cm, respectively. Moreover, for soft tissue specimens (e.g., spleen and liver), incisions with length of 1.0, 2.0, 5.0, 6.0 and 7.0 cm could be used to extract specimens with maximum diameters of 1.0, 3.0, 6.0, 8.0 and 10.0 cm, respectively. We have also attempted to extract adrenal pheochromocytoma specimens by enlarging the trocar port into a straight line in clinical practice. The specimen diameter was about 6.0 cm, and the adjuvant incision was about 4.0 cm. This is consistent with the results of our experiment. (Figure. 5)
In addition, when comparing specimens of the same diameter and different textures in the straight-line group, we found that soft tissue specimens with a diameter ≤3.0 cm were easier to extract than tough tissue specimens, whereas the opposite phenomenon was observed for specimens with a diameter >3.0 cm. These findings may be related to the fact that soft tissues were squeezed and deformed more when they pass through the adjuvant incision, making it difficult for them to pass through the incision. In addition, comparing the straight-line incision and inverted Y-shaped incision for soft tissue specimens with diameters of 6.0, 8.0 and 10.0 cm, we found that for larger specimens, the inverted Y-shaped incision can reduce the length of the extended incision, and the longer the incision is around the umbilicus, the more obvious this advantage is. (Figure. 6-7)
However, our experiment also has some shortcomings. First, we chose pig’s abdominal wall with the muscle layer instead of the whole abdominal wall. In the human body, there is a peritoneal layer in the wall in addition to the muscle layer, which also increases the resistance of specimen extraction. Second, specimens with different textures and shapes were lacking in the experiment, but in fact, the clinical surgical specimens of different texture and shape, and, so there may be result in the factor of differences between the experimental results and clinical practice. Third, to observe the measurement results, we extracted the specimen vertically upwards with a force measuring device (≤30 N). We manually removed the specimen only when the device was unable to extract the specimen (35 N). In clinical practice, the specimen needs to be extracted manually. Thus, the results may vary, which is the biggest limitation of our experiment.
In summary, although some studies have found that the adjuvant incision length is unrelated to complications, the fact that laparoscopic specimens can be removed through smaller adjuvant incisions not only has a cosmetic effect, but also relieve postoperative pain, short hospital stay and fast recovery of daily activities. Therefore, exploring the largest specimen that can be extracted by different sizes and shapes of adjuvant incision by simulating the extraction of laparoscopic specimens is of great clinical significance.