Comparing the image quality of myocardial perfusion agents in the clinical laboratory: small test groups and large reference populations.

Myocardial perfusion studies have been performed for 6 years using technetium-99m (99Tcm)-sestamibi (MIBI). In this study we evaluated a newer agent, 99Tcm-tetrofosmin (TF), on a trial basis for 2 weeks, and compared the results from each week to those in an adjacent week of MIBI use. The routine protocol included weight-based dosing, frequent dipyridamole use, and separate-day rest and stress wherever possible. During the first week, TF was used with 'usual' image timing, i.e. stress tomography performed 30-60 min after stress, and ancillary immediate images performed 4 min after injection. For the second week, 'early' tomography was performed 15-30 min after stress. TF scans (n = 53) were compared with MIBI scans for the adjacent weeks (n = 54) and with a historical reference series (n = 1800). Blinded analysis was made of tomographic image quality, peak myocardial counts and background activity (lung and abdomen) on immediate and delayed acquisitions and on tomographic reconstructions. The TF and MIBI test groups were similar with respect to gender, weight, stress protocol, tracer doses, imaging times and scintigraphic findings. Using analysis of variance, the tomographic quality scores were similar for the two observers, with stress>rest (P<0.0001), 'usual'>'early' (P<0.001) and MIBI>TF (P<0.05). Myocardial counts were approximately 20% higher with the MIBI test group than with TF at all times after stress (P=0.001), and were similar to the reference population. MIBI with usual timing gave more favourable stress abdominal background ratios than the other three agent/timing combinations. Satisfactory images could be obtained with TF, but no apparent advantage over MIBI could be attained with earlier post-stress imaging. Subtle advantages for MIBI over TF were suggested by comparison of the small test groups. In our local imaging context, these conclusions were reinforced by a large control series.

Laser instrumentation for intra-abdominal microlaser gynecologic surgery.

With proper laser instrumentation, the gynecologic microlaser surgeon enhances his ability to accomplish intra-abdominal fertility-promoting procedures in a safe and efficient manner.

Adhesion reformation and de novo adhesion formation after reproductive pelvic surgery.

At second-look laparoscopy, 82 of 161 women (51%) were noted to have adhesions at at least one new location. Such adhesions occurred at 31% of available sites. Among 121 women with adhesions at the initial operative procedure, the rate and type of recurrence assessed on the ovaries, fimbriae, and other sites were independent of the initial type. Additionally, neither the rate nor the type of adhesion recurrence observed at the time of second-look laparotomy was determined by the variable amount of time between the initial and second-look operative procedures. We conclude that reproductive pelvic surgical procedures are frequently complicated not only by adhesion reformation but by de novo adhesion formation as well.

Tubal reanastomosis: a comparison between microsurgical and microlaser techniques.

In order to evaluate the effect of the carbon dioxide laser as an adjunct to conventional microsurgical techniques, the authors retrospectively reviewed the charts of 53 patients who underwent tubal reanastomosis after elective sterilization. Thirty-two patients had non-laser microsurgical reanastomosis from 1981 to 1985; 21 patients had microlaser tubal reanastomosis from 1983 to 1985. All patients had unprotected intercourse for at least 1 year. In the non-laser group, 15 were known to have conceived, and in the laser group, eight had conceived; success rates were 43.7% and 42.9%, respectively. It is concluded that the carbon dioxide laser's advantages (precision, hemostasis, and the ability to preserve more normal reproductive tissue), although technically beneficial in performing microsurgical tubal reanastomosis, may not prove to be superior to conventional microsurgical technique as pregnancy rates are compared. Additional long-term studies are needed as more experience is gained to further delineate the role of the carbon dioxide laser for microsurgical tubal reanastomosis.

Laparoscopic assessment of ovarian healing following CO2 laser microsurgery: Vicryl vs. Surgilon.

A prospective multicenter study was undertaken by the Intraabdominal Laser Study Group to assess the type and extent of ovarian adhesions formed following incisional ovarian surgery performed as part of a fertility-promoting procedure with the aid of the carbon dioxide laser. Ovarian healing with subsequent adhesion formation was evaluated by early second-look laparoscopy. Two suture closing materials were used--Surgilon (siliconized braided nylon, David and Geck, Wayne, NJ) and Vicryl (polyglactin 910, Ethicon, Somerville, NJ). Sixty-five ovaries were evaluated in 37 patients with subsequent adhesions found in 37% (18/49) of the Surgilon-closed ovaries and in 94% (15/16) of the Vicryl-closed ovaries. The adhesions were filmy in 83% (15/18) of the Surgilon group and 47% (7/15) of the Vicryl group. Dense/vascular adhesions were found in 17% (3/18) of the Surgilon group and 53% (8/15) of the Vicryl group. The subsequent conception rates were 68% (17/25) in the Surgilon group and 33% (4/12) in the Vicryl group, although the small number of patients and multitude of infertility factors made pregnancy rate comparisons difficult. One of the authors noted lack of tensile strength in the Vicryl-closed ovaries within 12 weeks postlaser laparotomy, which led to incisional dehiscence during laparoscopic lysis of ovarian adhesions. From this preliminary study, it is concluded that additional data are needed to more fully resolve the debate on whether absorbable or nonabsorbable suture is preferred for ovarian infertility surgery.

Effects of denervation and delayed amputation on forelimb regeneration in Xenopus laevis froglets.

Left forelimbs of postmetamorphic Xenopus laevis froglets were repeatedly denervated prior to and following amputation. Amputations were performed 14, 21, 28, or 42 days after the original denervation. A tissue-regenerative response resulting in the formation of a spike-shaped, heteromorphic outgrowth was found in the sham-denervated and control animals, but dedifferentiation of the stump tissues was not apparent. Tissue-regenerative outgrowths were not observed in the denervated cases; instead, dermal wound healing and stump and scar formation occurred. In both control and experimental cases, however, a periosteal proliferative response to amputation injury led to the development of a greatly thickened periosteum the length of the amputated radius-ulna as well as a cap of cartilage at the distal end of these bones. We conclude from these results that forelimbs of postmetamorphic froglets are incapable of adjusting to a prolonged nerveless state sufficient to allow the normal tissue-regenerative response of spike outgrowth formation.

Clinical results of terminal salpingostomy with the use of the CO2 laser: report of the Intraabdominal Laser Study Group.

Forty-eight women underwent terminal salpingostomies with a standard operative procedure with the use of the CO2 laser and microsurgical techniques at five centers. Early second-look laparoscopy was performed in all patients 1 to 12 weeks after the laparotomy. The tubal patency rate at the second look was 92% for these 48 patients, with a minimum of 6 months' follow-up study in all patients. Of these patients, ten became pregnant (21%), one with an ectopic pregnancy (10%). All pregnancies occurred within 12 months of the second-look procedure. It is preliminarily concluded from this series that use of the CO2 laser for neosalpingostomy at laparotomy with early second-look laparoscopy provides a term pregnancy rate similar to that previously achieved by nonlaser microsurgical techniques and shortens the time period between the surgical procedure and when conception would be expected to occur.

[Instruments necessary for safe laser microsurgery]. / Instruments nécessaires pour une chirurgie micro-laser de sûreté.

Special instruments have been perfected for the laser microsurgery. Those instruments must not exceed 18 centimeters in length in order to reduce the possibility of infection through the middle part (microslad) tied up to the microscope. The instruments must be blackened to reduce the casual reflection of the laser ray over the intra-abdominal structures. Molybdenum mirrors with specifically outlined angles to reflect laser rays towards the inaccessible spots and also to strike the aimed tissue at the right place, have been perfected. In the same way, quartz straight and angular rods stronger to the laser fatigue than the pyrex are necessary to absorb laser energy during the vaporization and the excision of intra-pelvic adhesions. Thanks to these adapted instruments, the micro surgeon gynecologist will be able to practise his laser surgery with more safety, less eyestrain and less difficulties.

Current uses of the laser for fertility-promoting procedures.

The addition of lasers to the gynecologist's surgical armament has been heralded by some and scoffed at by many. Only through scientific assessment of published data using this new technique is one able to obtain an intelligent perspective of the clinical applicability for the laser in fertility-promoting procedures. A review of the literature, with stated pregnancy rates, describing the delivery of the carbon dioxide, argon, and Nd:YAG lasers via laparotomy or laparoscopy is presented. It is hoped that as this new surgical modality evolves, additional studies will further define its role in preserving or enhancing reproductive potential.

Metroplasty and myomectomy with the CO2 laser for maximizing the preservation of normal tissue and minimizing blood loss.

A study was designed to evaluate the efficacy of the CO2 laser in performing conservative uterine surgery, metroplasty and myomectomy; to determine blood loss using this technique; and to ascertain how much normal uterine tissue was preserved. To assess the effectiveness of this new surgical technique, 22 patients underwent metroplasty, myomectomy or both utilizing the CO2 laser. The blood loss via microlaser surgery was compared to that in a group of 14 patients who underwent conventional surgery. The initial findings indicated that the CO2 laser is a viable surgical instrument for myomectomy and metroplasty and that its use yields less blood loss and greater preservation of normal tissue.

Successful pregnancy outcome following removal of bilateral cornual polyps by microsurgical linear salpingotomy with the aid of the CO2 laser.

Various surgical approaches have been advanced to treat cornual obstruction secondary to intraluminal polyps. This case illustrates microsurgical principles incorporating the CO2 laser to maximize the preservation of normal uterotubal anatomy and function after excising large bilateral cornual polyps and multiple uterine myomata and vaporizing endometriosis and pelvic adhesions. The subsequent conception and delivery of a viable full-term infant demonstrates the efficacy of this new approach. Additional studies are warranted to further evaluate the role of microsurgical linear salpingotomy with the CO2 laser in the treatment of cornual polyps to enhance fertility.

Tubal patency and pelvic adhesions at early second-look laparoscopy following intraabdominal use of the carbon dioxide laser: initial report of the intraabdominal laser study group.

It has been suggested that the carbon dioxide (CO2) laser, by virtue of its hypothetical capabilities for precise incisions, minimization of tissue handling and bleeding, and shortened operating time, may improve the success rate of gynecologic infertility surgery. To assess this hypothesis, a multicenter prospective study was performed to assess tubal patency and adhesion formation at early second-look laparoscopy after intraabdominal laser surgery. Procedures performed included salpingoneostomy, fimbrioplasty, lysis of adhesions, vaporization of endometriosis, and ovarian wedge resection. The results were compared with those of another multicenter prospective study that utilized nonlaser reconstructive pelvic surgery. Use of the CO2 laser was found to result in a greater tubal patency rate at the time of the second-look procedure. Adhesions present at the time of the second-look procedure were reduced from initial presentation at most sites; however, nonlaser infertility surgery appeared to have equal or greater efficacy in the prevention of adhesion formation at most sites. Thus, the CO2 laser does not appear to be a panacea for the treatment of tuboperitoneal causes of infertility. Pregnancy rates following intraabdominal use of the CO2 laser remain to be established.

Evaluation of adhesion reformation by early second-look laparoscopy following microlaser ovarian wedge resection.

Early second-look laparoscopy, done 6 to 12 weeks postoperatively, was utilized to evaluate recurrent adhesion formation following microlaser ovarian wedge resection. Forty-nine ovaries in 25 consecutive infertility patients undergoing microlaser surgery for deep ovarian endometriosis or polycystic ovarian disease, refractory to medical treatment, were evaluated from October 1981 through March 1983. All patients subsequently underwent a second-look nonlaser laparoscopy to evaluate the extent of healing and to bluntly lyse any subsequent adhesions with the Olympus laparoscope (Olympus Corporation, Lake Success, NY) second-puncture probe: 36.7% of the ovaries had recurring adhesions, 83.3% of these adhesions were mild and filmy and 16.7% were moderate and dense. Additionally, four ovaries were viewed approximately 1 year postoperatively, with two ovaries that previously had mild and filmy adhesions lysed at 6 weeks having no recurrent adhesions. The actual pregnancy rate in this study is 60%, with 15 of the 25 patients conceiving at least once and 2 patients conceiving twice. The majority of pregnancies occurred within the first 6 months postoperatively, with the longest initial pregnancy occurring 22 months postoperatively. Thus, microlaser ovarian surgery, coupled with early second-look laparoscopy, appears efficacious in minimizing adhesion reformation and seems to have little adverse effect on subsequent conception.

Effects of delayed amputation on denervated forelimbs of adult newt.

Left forelimbs of adult newts were repeatedly denervated prior to and following amputation. Limb amputations were performed at 7-, 14-, 21-, 27-and 45-day intervals after the initial denervation. Regeneration was found in the sham-denervated and control animals but did not occur in any of the experimental cases; instead cicatrix formation and dermal wound healing ensued. Soft-tissue dedifferentiation was evident, however. We conclude from these results that forelimb regeneration in the adult newt is completely nerve dependent (for growth).

Levels of cyclic GMP and cyclic AMP in regenerating forelimbs of adult newts following denervation.

The effect of short-term denervation (0, 12, 24, and 72 hours) on the levels of cyclic 3'5'-guanosine monophosphate (cGMP) and cyclic 3'5'-adenosine monophosphate (cAMP) in adult newt (Notophthalmus viridescens) forelimbs at 15, 22, and 35 days of regeneration was investigated. Regenerate blastema and stump cyclic nucleotide levels were compared with those of the contralateral intact forelimb and hindlimb, with levels in the normally regenerating blastema, and with levels measured in the forelimbs of intact, nonoperated animals. Variations in cyclic nucleotide levels occurred according to regeneration stage and tissue type. Changes in level were noted immediately upon denervation and subsequently at other sample times in all regenerate and control series. Parallel fluctuations occurred in regenerate stump and contralateral intact forelimbs. Our results from nonamputated denervated and sham-denervated animals indicate that short-term, denervation-associated cyclic nucleotide fluctuations cannot be attributed solely to the loss of innervation.

Advanced surgical instrumentation needed for intra-abdominal application of the carbon dioxide laser in reproductive biology.

Rapidly expanding laser technology has created a void in surgical instrumentation when the carbon dioxide laser is applied to intra-abdominal microlaser fertility-promoting procedures. By using proper instruments, the laser microsurgeon will be able to enhance his surgical technique as well as reduce his frustrations.

Micro-laser myomectomy technique to enhance reproductive potential: a preliminary report.

Uterine myomas may be removed utilizing the carbon dioxide laser by direct and indirect vaporization, or by direct and indirect excision. The advantages of utilizing the CO2 laser are (1) improved hemostasis; (2) more precision, thus removing only abnormal tissue; and (3) the ability to remove fibroids from previously inaccessible areas. A description of the micro-surgical technique for myomectomy in eight patients is discussed. No major complications were encountered with this new technique, which will require long-term follow-up in a larger series of patients to define more precisely its role in gynecologic surgery.