A comparison of thermal injury, healing patterns, and postoperative adhesion formation following CO2 laser and electromicrosurgery

Preserved oxytocin-induced myometrium contraction and sensitivity to progesterone inhibition following rat uterus thermal insult. Impact on fertility

Women seeking improved fertility often undergo diagnostic hysteroscopy that could cause uterine thermal injury with unclear impact on uterine contraction, embryo implantation and fertility. We tested whether uterine thermal insult adversely affects myometrium function and contraction related receptors, channels, junctional proteins and remodeling enzymes. Female Sprague-Dawley rats were anesthetized, the left uterine horn was infused with 85 ℃ hot saline (thermal Insult) and the right horn was infused with 25℃ warm saline (control) for 3 min. After 7-days recovery, uterine strips were prepared for tissue histology and measurement of contraction, and mRNA and protein levels of oxytocin receptor, progesterone (P4) receptor A (PR-A), membrane K⁺ channel TREK-1, junctional protein connexin-43 (CX-43) and matrix metalloproteinases MMP-2 and MMP-9. Uterine tissue histology showed cellular swelling and inflammatory cell infiltration immediately following thermal insult, and recovery with no difference from control 7-days later. KCl (96 mM) and oxytocin (10^-13-10^-7 M) caused significant contraction that was not different in thermal insult vs control uterine strips. Pretreatment with P4 (10^-5 M) for 1 h caused marked inhibition of KCl and oxytocin contraction that was insignificantly greater in thermal vs control uterus. RT-PCR showed decreases in oxytocin receptor, PR-A, TREK-1, CX-43, MMP-2 and MMP-9 mRNA in thermal vs control uterus. Western blots showed decreases in oxytocin receptor, no change in TREK-1 and increased PRA, CX-43, MMP-2, and MMP-9 protein levels in thermal vs control uterus. To assess the impact on fertility, female rats were housed with male rats, and on gestational day 19, the litter size, pup weight and crown-rump length, and placenta weight were not different in thermal vs control uterus. Thus, after thermal insult-induced immediate inflammation and reduced heat-sensitive mRNA expression, the uterus undergoes a recovery and adaptation process involving preserved oxytocin-induced contraction, P4 inhibition and TREK-1 channels. The uterus self-healing process appears to require improved PR-A signaling, intercellular communication via CX-43 and tissue remodeling by MMP-2 and MMP-9. The uterine thermal recovery processes could be essential for maintaining fertility and future pregnancy outcome.

Adhesions from flexor tendon surgery: an animal study comparing surgical techniques

Intraoperative and postoperative hemorrhage has long been considered a cause of tendon adhesion and, thus, scarring and poor surgical results. To prevent such problems bipolar coagulators are commonly used during surgery to help achieve hemostasis. Surgical lasers also have been reported to help limit bleeding and scar formation. Very little is known regarding the relationship between hemorrhage and/or direct tendon tissue effects and tendon adhesions with the use of these modalities. We compared 3 different surgical techniques (meticulous sharp scalpel dissection, scalpel dissection plus bipolar coagulation, and CO(2) laser dissection) and used chicken flexor tendons to biomechanically and histologically assess the amount of adhesion formation after each procedure. Our findings show that bipolar coagulation and CO(2) laser application are both associated with significantly increased adhesion formation in tendon surgery compared with sharp dissection alone and that the meticulous, conventional sharp dissection technique is the best method to control adhesion formation. These conclusions have relevance to clinical tendon surgery.

Comparison of the ultrasonic scalpel to CO2 laser and electrosurgery in terms of tissue injury and adhesion formation in a rabbit model

OBJECTIVE

To determine the relative effect of an ultrasonic scalpel on reproductive tissue compared with CO2 laser and electrosurgery.

DESIGN

Prospective, randomized animal study.

SETTING

University laboratory setting.

ANIMALS

Sixteen New Zealand White rabbits.

INTERVENTION(S)

A steel scalpel, an ultrasonic scalpel, a CO2 laser, or electrosurgery were used to perform an ovarian wedge resection and to remove the distal uterine horn. A 3-cm longitudinal incision also was made in the uterine horn.

MAIN OUTCOME MEASURE(S)

The number of 1-second bursts of needle-tip electrosurgery required for hemostasis, the depth and degree of coagulation necrosis, degree of fibrin deposition, and postoperative adhesion formation.

RESULT(S)

The amount of electrosurgery needed to achieve hemostasis was less for any of the four power techniques than for the steel scalpel, with the exception of the ultrasonic scalpel at level 5 when used on the ovary. The depth (range: 0.30 to 0.38 mm) and the degree of coagulation necrosis was not different for any of the power techniques. The fibrin score was greatest for the ultrasonic scalpel at level 5 in both the ovarian tissue and the uterine tissue. There was no difference in adhesion scores for the power techniques and the steel scalpel.

CONCLUSION(S)

The ultrasonic scalpel at level 3 is not different from either CO2 laser or electrosurgery in terms of hemostatic properties, coagulation necrosis, or adhesion formation in the rabbit model.

Sharp Dissection, Electrosurgery, and Argon-Enhanced Electrosurgery in Porcine Skin Flaps

Sharp scalpel dissection, electrosurgery, and argon-enhanced electrosurgery (argon beam coagulation) were used to elevate random pedicled skin flaps in a randomized, blinded fashion with a porcine model. A total of 72 flaps on 9 pigs were examined. Flap survival was quantified, and histology was also reviewed 2 and 6 weeks after surgery. No significant difference among the three techniques was noted in terms of area or length of surviving flaps. There were also no histologic differences noted with regard to fibrosis, inflammatory infiltrate, or necrosis. We conclude that the use of electrosurgery during surgical dissection of random pedicled skin flaps is not detrimental to wound healing or tissue survival, and it provides benefits such as decreased blood loss, absence of the need for sharp instruments in the surgical field, and faster operative times.

Loop electrosurgical excision with a laparoscopic electrode and carbon dioxide laser vaporization: comparison of thermal injury characteristics in the rat uterine horn

OBJECTIVE

Our purpose was to compare the thermal intraperitoneal injury in lesions resulting from a monopolar electrosurgical loop electrode designed for laparoscopic surgery with similar lesions fashioned by carbon dioxide laser vaporization.

STUDY DESIGN

A randomized, observer-blinded comparison was made of histopathologically measured thermal injury in rat uterine horns. The primary outcome measure was the depth of necrotic debris and coagulative necrosis in the lesions created by the two methods.

RESULTS

The depth of coagulative necrosis was similar in the laser vaporization (0.118 +/- 0.028 mm) and the loop excision groups (0.165 +/- 0.167 mm). However, the average amount of necrotic debris was greater in the lasered lesions (0.053 +/- 0.019 mm) compared with those made with the loop electrode (0.013 +/- 0.011 mm).

CONCLUSIONS

The depth of coagulative necrosis in rat uterine lesions fashioned with a loop electrode is similar to that of lesions created by carbon dioxide vaporization at power densities comparable with those usually achieved at laparoscopic surgery. There is a greater amount of necrotic debris in the lasered lesions. This suggests that electrosurgical loops designed for laparoscopic surgery may have promise for the cost-effective excision of intraperitoneal tissue.

Operative laparoscopy: surgical modalities

OBJECTIVE

To review basic physics of different surgical modalities and their clinical applications and outcomes.

DESIGN

The relevant literature and personal experience were used to prepare the manuscript.

RESULTS

Operative laparoscopy is safe and effective whether using sharp dissection, electrosurgical, or laser energy. The newer surgical modalities, including the vibrating ultrasound scalpel and argon beam coagulator, need further evaluation.

CONCLUSIONS

The results of laparoscopic surgery are independent of the surgical modality used. The surgeon's skill and experience, his or her preference of the technique, and proper patient selection play a more important role.

Laparoscopic surgery of chronic hyperandrogenic anovulation

The review describes briefly the clinical and endocrinological characteristics of chronic hyperandrogenic anovulation (CHA), as well as ovulation induction by hormone therapy (therapy of first choice) and by classical wedge resection. The main purpose of this study, however, is to compare different laparoscopic treatments of CHA, with emphasis on laser treatments by argon, CO2, Nd:YAG, and frequency-doubled Nd:YAG laser. The overall results of laparoscopic treatments in hormone-therapy-resistant patients with CHA are encouraging and the results are comparable. In the studies considered in this review, ovulation was induced for longer or shorter periods in 21 out of 31 patients (68%) after ovarian biopsy, in 57 out of 73 patients (78%) after electrosurgery, and in 82 out of 118 patients (70%) after laser treatment. Subsequent conception occurred in 44%, 40%, and in 41% of the patients, respectively. Of interest is the fact that some hormone-therapy-resistant patients become sensitive to Clomiphene after laparoscopic treatment, giving an overall percentage of ovulation and an overall pregnancy rate of 89% and 54%, respectively, for electrosurgery, and of 88% and 50%, respectively, for laser treatment. Unfortunately, adhesion formation, a serious complication of surgical treatment of the ovaries, is still a drawback using laparoscopic surgical techniques.

Adhesions after extensive gynecologic surgery: clinical significance, etiology, and prevention

Postoperative adhesions occur in 60% to 90% of patients undergoing major gynecologic surgery and represent one of the most common causes of intestinal obstruction in the industrialized world. The incidence of adhesion-related intestinal obstruction after gynecologic surgery for benign conditions without hysterectomy is approximately 0.3%, increasing to 2% to 3% among patients who undergo hysterectomy, and is as high as 5% if a radical hysterectomy is performed. Other adhesion-related complications include chronic pelvic pain, ureteral obstruction, and voiding dysfunction. Intraperitoneal adhesions also can limit the effectiveness of intraperitoneal therapeutic agents used in cancer treatment. Postoperative adhesions are sequelae of impaired fibrinolysis of the fibrin and cellular exudate after peritoneal injury. Adequate blood supply is essential for normal fibrinolysis. Therefore factors that increase ischemia and potentiate adhesion formation include thermal injury, infection, presence of a foreign body, and radiation-induced endarteritis. Only recently, appropriate animal models have been developed to study the process of adhesion formation and prevention. Until clinical confirmation of findings from these investigations exists, only a meticulous surgical technique can be advocated to minimize these untoward effects of surgery.

Adhesions after extensive gynecologic surgery: clinical significance, etiology, and prevention

Postoperative adhesions occur in 60% to 90% of patients undergoing major gynecologic surgery and represent one of the most common causes of intestinal obstruction in the industrialized world. The incidence of adhesion-related intestinal obstruction after gynecologic surgery for benign conditions without hysterectomy is approximately 0.3%, increasing to 2% to 3% among patients who undergo hysterectomy, and is as high as 5% if a radical hysterectomy is performed. Other adhesion-related complications include chronic pelvic pain, ureteral obstruction, and voiding dysfunction. Intraperitoneal adhesions also can limit the effectiveness of intraperitoneal therapeutic agents used in cancer treatment. Postoperative adhesions are sequelae of impaired fibrinolysis of the fibrin and cellular exudate after peritoneal injury. Adequate blood supply is essential for normal fibrinolysis. Therefore factors that increase ischemia and potentiate adhesion formation include thermal injury, infection, presence of a foreign body, and radiation-induced endarteritis. Only recently, appropriate animal models have been developed to study the process of adhesion formation and prevention. Until clinical confirmation of findings from these investigations exists, only a meticulous surgical technique can be advocated to minimize these untoward effects of surgery.

The YAG laser used in micromanipulation to transect the zona pellucida of hamster oocytes

PROBLEM

Since there has been no reported use of the YAG laser to micromanipulate oocytes, our purpose was to study whether (1) a YAG laser could be used to open the zona pellucida of hamster oocytes; (2) human sperm could reach the ooplasm and (3) under sperm penetration assay conditions, sperm would bind and penetrate the ooplasm.

RESULTS

A YAG 100 laser was used at 10 W and 0.4-sec pulse width to open eight of eight ooplasm oocytes. The opening in the zonae was 0.25 to 1.0 rad (10 to 40 microns). For the initial eight oocytes and two parallel controls, the coarse appearance of the ooplasm was unchanged after 3 days. Next, in 11 of 12 manipulated oocytes, the sperm clustered at the opening of the zona. When 16 more oocytes were opened and exposed to sperm in sperm penetration assay conditions, each ooplasm bound sperm. There was no penetration noted. Each manipulation time was < 1 min. To clarify the laser effect, oocytes were exposed to laser energy then utilized as the interactive surface in the sperm penetration assay. It was found that only 20% bound sperm with no penetration.

CONCLUSION

While the time factor compares favourably with other methods of zona opening, further study needs to be performed to minimize effect to the exposed oocyte.

Incidence of adhesions following thermal tissue damage

Coagulation and vaporization of tissue are techniques applied in pelviscopic surgery in order to achieve hemostasis as well as cut and destroy endometriotic implants. An animal experimental study was devised to show if there is a difference in the incidence of adhesions after vaporization of equal-sized areas of the anterior abdominal wall of the rat compared to coagulation of equal-sized areas. A similar depth of the lesions was achieved by repeating the vaporization procedure. The rate of adhesions was significantly lower (P less than 0.001, Chi2-test) post-coagulation, using a biopolar high frequency current or post-endocoagulation than post-vaporization. The surface vaporization of tissue, for example endometriotic implants, as produced by laser is to be viewed critically as regards the higher incidence of adhesions after vaporization compared with coagulation.

Ovarian function after incision of the ovary by scalpel, CO2 laser, and microelectrode

OBJECTIVE

The objective was to evaluate the relative effects of a standardized surgical incision performed with scalpel, CO2 laser, or microelectrode on ovarian tissue and function.

DESIGN

Thirty sexually mature female rabbits were randomly assigned to one of three surgical groups. The injury consisted of a linear incision along the long axis of both ovaries, from the cortex to the hilum, followed by immediate unilateral oophorectomy for evaluation of the acute tissue damage. The opposite ovary was left in situ to evaluate subsequent healing, steroidogenesis, folliculogenesis, and ovulation.

RESULTS

Minimal damage was observed after surgery with either laser or microelectrode. The ovarian stroma and follicles adjacent to the surgical site appeared normal both immediately and 15 days after all surgeries. Steroidogenesis, folliculogenesis, and luteinization were similar among the three groups. The number of ovulated oocytes after human chorionic gonadotropin was significantly reduced after scalpel and laser surgery compared with microelectrode (P less than 0.05). The former groups appeared to have a higher incidence of unruptured luteinized follicles with untrapped oocytes, which were often covered with a cellular fibrous membrane.

CONCLUSIONS

These findings suggest that surgical trauma is well tolerated by the ovaries and does not impair subsequent ovarian function. However, rupture of the preovulatory follicle and its release of the oocyte may be influenced by the presence of ovarian adhesions and/or surgical trauma.

Adhesion reformation after reproductive surgery by videolaseroscopy

After initial videolaseroscopy for the treatment of endometriosis-associated infertility, 157 patients underwent a second-look laparoscopy to evaluate and treat recurrence of disease and/or adhesions. The patients were divided into two groups. Group 1 consisted of 135 patients who underwent second-look laparoscopy for persistent infertility and/or recurrence of pain. Group 2 consisted of 22 patients who achieved pregnancy after initial surgery and underwent second-look laparoscopy for evaluation of ectopic pregnancy or in association with uterine evacuation for first trimester spontaneous abortion. Both groups of patients demonstrated a significant reduction in adhesion scores involving the ovaries, tubes, posterior cul-de-sac, anterior cul-de-sac, and omentum/bowel. Although the initial mean adhesion scores were similar for both groups, at second-look laparoscopy the mean adhesion scores were significantly lower for group 2, particularly for ovarian and tubal adhesions. None of the patients formed de novo adhesions. From these results we may conclude that videolaseroscopy: (1) is effective in reducing peritoneal adhesions; (2) is associated with a low frequency of postoperative adhesion recurrence; and (3) appears to completely avoid de novo adhesion formation.

Assessment of results of laser surgery

The use of lasers in reproductive pelvic surgery has been established, based more on the reports of clinical experience than demonstration of improved efficacy as compared to other therapeutic modalities. Superiority of one type of laser over another has not been demonstrated. It is the author's opinion that the advantage of using lasers lies in the ability to treat pelvic pathology endoscopically rather than at laparotomy. We have been trained in the use of the laser and find it to be of great use; it is quite possible, however, that other physicians, trained in alternative endoscopic techniques, can achieve similar results. Of course, appropriate clinical trials are needed so that surgical treatments can be based on scientific knowledge rather than clinical impressions. Until such time that this information is available, however, experience gained from clinical observation and reports of clinical outcome do serve as guides for counselling and treating our patients.