Anatomical sizes of the human vas deferens after vasectomy.

After vasectomy, the lumen of the testicular side of the vas deferens dilates, apparently because of internal pressure from accumulation of spermatic fluid. This dilatation occurs within the 1st postoperative year. It causes a thinning of the wall of the vas without significant increase in the external diameter. The extent of dilatation is similar in the same man, but differs markedly between individuals, the mean increase in diameter being approximately 70%. The implications of this difference in size are discussed with regard to vas anastomosis and to the possible use of devices to rejoin the vas or to bridge a defect created by a prior vasectomy.

Development of a reversible vas deferens occlusive device. VI. Long-term evaluation of flexible prosthetic devices.

Fifty-three dogs received implants of several types of flexible devices containing valving mechanisms. These devices were constructed entirely of silicone rubber with the exception of the valve stem, which was made of stainless steel. Generally, the devices were (1) implanted in the open mode and left this way for 27 to 44 months, (2) implanted in the closed mode and kept this way for 11 to 12 months before the valves were reopened, (3) implanted in either the closed or open mode and cycled to the opposite mode every 3 months (four or five cycles), or (4) implanted in either the closed or open mode and cycled to the opposite mode every 6 months (two or three cycles). Different implant methods were also evaluated. Semen analyses were regularly performed on all of the dogs, and a number of the animals were bred during the experiments. It can be concluded that (1) the devices can be opened and closed successfully over long periods, respectively allowing and preventing sperm transport; (2) the breeding ability of the animals is not impaired while the devices are in the open mode, independent of the type of device; (3) the devices do not result in an enhanced incidence of congenital abnormalities in the offspring; and (4) the success rate of device performance does not depend on the method of implanatation used. Thus, the results clearly indicate that the basic mechanism of a soft, reversible valve is a feasible approach to conception control.

The human uterotubal junction: a scanning electron microscope study during different phases of the menstrual cycle.

Uterotubal junctions from surgically extirpated human uteri were examined. The specimens were obtained during different phases of the menstrual cycle. The interstitial portions of the tubes together with the cornual areas were dissected, excised, and their luminal surfaces exposed. The specimens were then processed for scanning electron microscopy. The surface epithelium of both the cornual endometrium and interstitial endosalpins. Ciliated cells were more numerous in the endosalpinx. Cyclic changes in ciliated cells were minimal, while cyclic secretory activity was demonstrated, especially in the endometrium. The transitional area between the endometrium and the endosalpinx was characterized by a marked increase in the number of ciliated cells, and a tendency of the secretory cells to assume a flattened, polygonal shape. These morphologic features suggest a possible role in the transport and/or maintenance of spermatozoa and/or ova.

PIP: Uterotubal junctions from hysterectomy specimens, obtained at different phases of the menstrual cycle, were examined by scanning electron microscopy. Ciliated and secretory cells, with common morphologic characteristics, were observed in the surface epithelium of both the cornual endometrium and interstitial endosalpinx, with ciliated cells being dominant in number in the endosalpinx. Changes in ciliated cells were minimal during the menstrual cycle, though secretory cell act ivity was apparent, particularly in the endometrium. A considerable inc rease in the number of ciliated cells was observed in the transitional area between the endosalpinx and the endometrium. There was also a tendency of the secretory cells to assume a flattened, polygonal shape in the same region. The observed changes are suggestive of a possible role of the uterotubal junction in the transport of maintenance of spermatozoa or ova.

Development of a reversible vas deferens occlusion device. VII. Physical and microscopic observations after long-term implantation of flexible prosthetic devices.

Flexible prosthetic devices developed previously to reversibly block sperm transport through the vas degerens were implanted in the vasa deferentia of dogs or kept in a semen bath for a 6-month period. Dimensional measurements, flow characteristics, leakage tests, and detent action force tests to displace the valve stem were performed with the valves. No changes occurred in any of these parameters with the exception of a decrease in the force required to change the position of the valve stem. This explains the occasional passage of spermatozoa through certain closed devices after they have been implanted for long periods of time. Histologic studies indicated that the same types of genital tract changes are associated with an implanted device as with vasectomy, and that they occur with approximately equal frequencies. Scanning electron microscope studies showed (1) excellent tissue ingrowth into the Dacron velour material of the implanted device; (2) the build-up of material, consisting in part of spermatozoa, in the device lumen and on the value stem; and (3) the absence of surface degradation of either the Silastic material or the valve stem of the device. It is concluded that no irreversible tissue damage is caused by the long-term implantation of flexible prosthetic devices into the vas deferens.

Development of reversible vas deferens occlusive device: V. Flexible prosthetic devices.

In contrast to the results with rigid-ended prosthetic devices implanted in the vas deferens of the dog, effective sperm transport was obtained for prolonged periods of time with flexible-ended (all soft) devices. Such transport could be halted by device occlusion with clips or shuttle stem valves. Opening the devices resulted once again in the passage of spermatozoa, indicating that these devices may be potentially useful as reversible male contraceptives. More research is necessary to determine the cause of an overall decrease in sperm output after device implantations and to evaluate any adverse side effects of such devices. Dacron velour-covered suture rings on the devices permitted effective tissue ingrowth and prevented leakage or recanalization.

Medical student perceptions of family practice opportunities.

This study was conducted to obtain information concerning family practice opportunities in Chicago and to compare the actual availability with students' perceptions of such opportunities. Questionnaires received from 85 hospital administrators (98% response rate) indicated that 93% of the Chicago-area hospitals had open staff positions for family physicians. Comparison data were obtained from another questionnaire completed by 201 medical students (39%). The students' average estimate of the percentage of hospitals having positions available for family physicians was 45%. This suggested that the students greatly underestimated the availability of staff positions for family physicians.

Reversible occlusive devices.

PIP: Research in the development of reversible vas and tubal occlusive de vices is reviewed. Flexible vas deferens occlusive device have been found to be safe and effective in dogs. Theses devices incorporate a stainless steel shuttle stem valve which can be repeatedly turned on and off. The rigid vas occlusive devices have a tendency to perforate the vas deferens. The flexible device can be implanted in either the transected vas or by a dual-incision technique. The device has been successfully attached to the vas, without leakage, by application of a Dacron velour ingrowth material. Those designs which utilize a shuttle stem which directly impedes the flow of spermatozoa appear to be more effective than those which depress a continuous rubber tube. Experiments on baboons with tubal occlusive devices have shown that the devices blocked the flow of dye contrast material. Nonetheless, the transcervical approach to the implantation of such devices is only in the early stages of development. The development of a steerable hysteroscope should enhance the potential for the transcervical approach and the types of devices that can be implanted.^ieng

New studies with intravasal devices. The soft valve.

In contrast to the results that were obtained with rigid ended prosthetic devices, effective sperm transport occurred for prolonged periods of time through the IITRI Vas-Valve, which had soft silicone rubber flexible end tubes when implanted in the vasa deferentia of dogs. Such transport could be halted by device occlusion with stainless steel springs or with shuttle stem valves. Opening the devices resulted once more in the passage of spermatozoa as well as the production of offspring, indicating that these devices have the potential for being useful as a human male contraceptive method. More research needs to be performed to determine why there is an over-all decrease in sperm output after device implantation and to evaluate and adverse side effects of such devices. The presence of Dacron velour-covered suture rings on the devices permitted effective tissue ingrowth and prevented leakage or recanalization in all cases.

A prosthetic vas deferens.

Six dogs were implanted with the synthetic vas deferens device as part of our continuing research into the development of a reversible occlusive device for implant in the transected vas deferens. The experimental objectives were to assess the effects of sperm path length and duration of aspermia on total sperm count and motility by implanting three different lengths of the device in animals with different degrees of aspermic duration induced by bilateral vasectomy. Device lengths varied from 1.55 cm to 4.3 cm including the pilot tubes. The prosthesis is fabricated entirely of silicone rubber with Dacron velour tissue ingrowth material bonded to the outside surface of the ring to which vas ends are sutured. The pilot tubes extend 4 mm beyond the suture rings and are 0.6 mm OD with a 0.3 mm ID that extends through the entire length of the device. The flexible pilot tubes are an important feature of this design and insert into the vas lumen ensuring alignment between the device and the vas deferens while maintaining the necessary resiliency to adapt to the inherent movements of the vas without perforation. All animals included in these experiments were carefully selected and conditioned before implant. The evaluation of performance was based on semen samples collected at one week intervals. Sperm subsequently appeared in the ejaculate of all 6 dogs, demonstrating that the restoration of sperm transport can be restored after bilateral vasectomy through the implantation of a prosthetic vas deferens. The potential application of this device to the human male for the restoration of fertility appears excellent.

An experiment in medical education. A critical analysis using traditional criteria.

In 1984, in addition to its standard traditional curriculum, Rush Medical College (Chicago, Ill) developed a Socratic problem-based method of teaching basic science material called the alternative curriculum. As part of an evaluation of this new curriculum, students in the two curricula were compared using three traditional measurements: (1) test scores from the National Board of Medical Examiners, Part I; (2) test scores from the National Board of Medical Examiners, Part II; and (3) performance on an oral examination. Alternative curriculum students did not differ significantly from their traditional curriculum classmates on National Board of Medical Examiners, Part I and Part II total scores, although their subset scores on Part I did tend to be lower, reaching significance in one subset area. Differences in performance favoring the traditional curriculum were primarily seen in the early years of the program. Alternative curriculum students in the class matriculated in 1987 scored significantly higher in three of five categories on the oral examination.

Transcervical tubal occlusion with a steerable hysteroscope: implantation of devices into extirpated human uteri.

A new steerable fiberoptic hysteroscope particularly useful in visualizing the tubal ostia has been evaluated in 61 extirpated uteri. The efficacy and safety of this hysteroscope were shown. The feasibility of deploying occlusive devices into the intramural portion of the tubes with the steerable hysteroscope was demonstrated. Whether these devices or modifications thereof will prove to be superior to other currently tested methods of occlusion, e.g., caustics, plastics, or cautery under in vivo conditions, remains to be established. The steerability of the hysteroscope has advantage irrespective of the method to achieve transcervical tubal occlusion as it allows coaxial alignment of the delivery.

PIP: A new steerable fiberoptic hysteroscope was evaluated in 61 extirpated human uteri. 99 of the 122 tubal ostia were positively identified (81.2%). Successful placement of tubal occlusive devices was achieved, in 53 of 90 cases, though experience with the instrument improved this rate. Technical reasons for the failure to deploy the occlusive devices entirely within the interstitial portion of the tube are discussed. A principal advantage of the steerable hysteroscope for transcervical tubal occulsion, irrespective of the occlusive method used, is that it permits coaxial alignment of the delivery channel and the tubal ostium.

Development of a steerable hysteroscope: studies in the baboon.

A steerable fiberoptic hysteroscope was developed with an integrated fluid circulatory system and a channel that can be used either for operative procedures or for the passage of a uterotubal occlusive device delivery assembly. The hysteroscope was demonstrated to be a safe and practical instrument for intrauterine observations, using the baboon as the animal model. Postpartum baboons were used for a majority of the experiments since the cervix of most cycling animals could not be sufficiently dilated to permit hysteroscope insertion. Estrogen-progesterone treatment resulted in softening of the cervix enough to allow hysteroscopic examination in 66 per cent of the animals so treated. Hysteroscopy was performed on 18 baboons. In almost all cases the uterotubal junctions were visualized and appeared as small slits or depressions. Measurements of the mean uterine length, fundal width, normal cervical diameter, and the diameter to which the cervix can maximally be dilated are reported for cycling, hormone-treated, and postpartum baboons.

PIP: A newly developed steerable fiberoptic hysteroscope was evaluated in baboons. The instrument has an integrated fluid circulating system for controlling uterine expansion, and a channel that can be used for operative procedures or for the introduction of an uterotubal occlusive device delivery system. A dual-viewing eyepiece can be easily attached to the instrument. A combination estrogen-progesterone treatment sufficiently softened the cervix to allow uterine visualization in 66% of the treated animals. In the hysteroscopic examination of 18 baboons, the interstitial uterotubal junctions, appearing as small slits or depressions, were usually visualized. The mean uterine length, fundal width, normal cervical diameter, and the maximum width to which the cervix can be dilated are reported for normally menstruating, hormone-treated, and postpartum baboons.