Experimental laser anastomosis of the colon. Long-term results and histologic findings after laser closure of colotomies

End-to-end intestinal anastomosis using a novel biodegradable stent for laparoscopic colonic surgery: a multicenter study

PURPOSE

Our animal studies have demonstrated the safety and feasibility of end-to-end intestinal anastomosis using a stent for laparoscopic colonic surgery. Therefore, we designed a non-inferiority trial to investigate the outcomes of stent anastomosis (SA) vs. those of conventional hand-sewn anastomosis (CA).

METHODS

A multicenter randomized controlled trial was conducted between December, 2016 and April, 2018. The primary outcome was the healing condition of the anastomoses, evaluated by endoscopy 6 months postoperatively. The secondary outcomes were the anastomotic completion time, anastomotic leak, intestinal obstruction, peritoneal effusion, and bleeding. Quality of life (QOL) was evaluated by questionnaires.

RESULTS

The subjects of this study were 60 patients, randomly divided into a SA group (n = 30) and a CA group (n = 30). There were no differences in anastomotic healing conditions (P = 1.00). The stent procedure was associated with a significantly shorter anastomosis time than the hand-sewn anastomosis (13.517 ± 4.281 vs. 20.333 ± 2.998 min, respectively; P < 0.001). There were no significant differences in anastomotic leakage, intestinal obstruction, peritoneal effusion, or bleeding between the groups. Questionnaires revealed almost no discrepancy between baseline QOL scores and those assessed 2, 4, 8, 12, and 24 weeks postoperatively in either group.

CONCLUSIONS

Intestinal anastomosis with a stent is a non-inferior strategy for laparoscopic colonic surgery, which requires less time for the anastomosis.

An Automatic Suturing Machine for Intestinal Anastomosis: Advantages Compared With Hand-Suturing Technique

One of the main procedures in intestinal surgery is anastomosis, which is mostly performed by stapling or hand suturing. Due to limitations of these methods, a novel automatic suturing machine was designed and fabricated in this study, equipped with a needle-driving system; a thread control mechanism, and a linear mechanism, which is applicable in intestinal anastomosis by making continuous sutures. The main advantages of the fabricated machine are employing biocompatible suture, from the tissue's adaptation point of view, and making a uniform suturing pattern, independent of surgeon's skill, and thus offering a greater strength than the hand-sutured specimen. In order to evaluate the capability of the fabricated machine and investigate the validity of the hypothesis made in this study, that is, a more uniform suture will result in a greater mechanical strength of the sutured tissue, in vitro tests were performed on human intestine specimens, which were manually sutured by an expert surgeon and by the automatic suturing machine. The tensile tests with an elongation rate of 5 mm/min were done for 90 specimens, in 9 groups with various suturing configurations. The optimum pattern, from the mechanical strength point of view, was found to be the same in both manual and automatic suturing methods, that is, h7 d6 ( h = distance of suture from the edge of the tissue = 7 mm, and d = distance between stitches = 6 mm). It was also shown that the maximum breaking strength, for the best suturing pattern, h7 d6, is significantly greater when the automatic suturing machine was employed, compared with the hand-sutured tissue ( P < .001).

Experimental study of colonic anastomosis with a degradable stent in a porcine model

BACKGROUND

Intestinal anastomosis is a major technical component of gastrointestinal procedures. We have developed a new procedure of colonic anastomosis with a degradable stent. This article evaluates this procedure.

METHODS

Forty pigs were assigned randomly to a stent group (n = 20) and a control group (n = 20). A colonic anastomosis with a degradable stent was performed in the stent group, and hand-sewn anastomosis was performed in the control group. Pigs of each group were divided evenly into 4 subgroups according to time of death (days 3, 7, and 14, and month 10 postoperatively) to evaluate the healing of anastomosis.

RESULTS

All procedures were completed successfully. The surgical time of the stent group was significantly less than the control group. No complications occurred in either group. Bursting pressure of the stent group was significantly higher than the control group on postoperative days 3 and 7. No significant difference of hydroxyproline content or microvessel density was found between the 2 groups.

CONCLUSIONS

The procedure of colonic anastomosis with a degradable stent is a simple, feasible, and safe procedure in this porcine model.

Effects of scalpel, electrocautery, and CO2 and KTP lasers on wound healing in rat tongues

OBJECTIVE

Evaluate wound healing of incisions created by the scalpel, electrocautery, CO2 laser, and potassium titanyl phosphate (KTP) laser in the upper aerodigestive tract in an animal model.

STUDY DESIGN

Prospective randomized study in an animal model.

METHODS

Postoperative oral intake, histologic depth of injury, and tensile mechanical strength were measured in rat tongues after creating incisions using a scalpel, electrocautery, CO2 laser, and KTP laser. An unpaired, two-tailed Student's t-test was used to compare results between the experimental groups.

RESULTS

Oral intake, indirectly assessed by postoperative weight loss, by the third postoperative day was significantly decreased in the electrocautery (P = 0.004), CO2 laser (P = 0.001), and KTP laser (P = 0.0001) groups as compared with the scalpel group. The depth of the wound healing, as assessed by histologic examination, was successively greater for the scalpel (75 +/- 13 microm), electrocautery (110 +/- 10 microm), CO2 laser (145 +/- 10 microm), and KTP laser (195 +/- 23 microm) groups. However, this difference was only statistically significant for the CO2 laser (P = 0.006) and KTP laser (P = 0.01) groups relative to the scalpel group. Wounds created by the KTP laser had the lowest strength (76.5 +/- 6.9 kPa) as compared with the CO2 laser (156 +/- 28.4 kPa), electrocautery (153 +/- 15.7 kPa), and scalpel groups (249 +/- 61.8 kPa). This difference was only statistically significant for the KTP laser group (P = 0.02) when compared with the scalpel group.

CONCLUSIONS

Wounds created in the upper aerodigestive tract of rats by scalpels result in the least postoperative weight loss, tissue destruction, and decrease in tensile strength, whereas wounds created by the KTP laser demonstrated a significantly greater postoperative weight loss, depth of wounding, and decrease in tensile strength.

First experimental sutureless laser anastomosis of the large bowel: long-term study

Large bowel anastomoses were successfully performed without sutures on New Zealand white rabbits using 1,064 nm, 0.4-W power pulsating Nd:YAG laser to create tissue welding.

PURPOSE

The aim of this study was to assess long-term results of our experimental data and summarize our experimental work on laser colon anastomosis.

METHODS

This experimental study investigated long-term integrity, degree of narrowing, animal body weight change, visual findings, microscopic appearance, and collagen concentration of laser colon anastomoses, compared with those of conventional sutured anastomoses at thirty and ninety postoperative days.

RESULTS

Two animals in the laser group died without leakage. Postsurgical course in all remaining rabbits studied was uneventful. Bursting pressures in the two groups were equivalent, but the laser group exhibited a consistent narrowing tendency. However, laser anastomoses demonstrated fewer and milder adhesions, and animals showed a better recovery of body weight. Histologically, laser anastomoses showed better layer-to-layer reconstitution without foreign body response and with less fibrosis. Difference in collagen (hydroxyproline) concentration did not reach statistical significance.

CONCLUSION

The nature of tissue welding via laser remains undefined, but there is definitely a future for laser bowel anastomosis.