The sixth batch of Mansoura Manchester programme

The sixth batch of Mansoura Manchester programme
Professor: Alaa Mosbah , Mansoura Manchester programme

Friday, December 28, 2007

Embryology of the Genital Tract

-The reproductive organs in the female consist of external genitalia, gonads, & internal duct system between the two. -The genital organs develop close to those of the urinary tract. Both arise in intermediate mesoderm on each side of the root of the mesentery underneath the coelomic epithelium -The pronephros, a few transient excretory tubules in the cervical region, appears first. These tubules quickly degenerate, but its caudal end persists and open at the cloaca. -Connection will ultimately be established between this duct and some of the tubules of the mesonephros which soon appears and the duct is known as the mesonephric duct. -The mesonephros, a second primitive kidney, develops as a long prominent swelling bulging into the dorsal wall of the coelom in the thoracic and upper lumbar regio ORIGIN OF THE MULLERIAN DUCTS 1-DEVELOPMENT OF THE UTERUS AND TUBES -At the 4 th week after fertilization, the mullerian ducts first appear lateral to each wolffian duct as invaginations of the dorsal coelomic epithelium. -Each bud penetrates the mesenchyme lateral and parallel to each wolffian duct. As the solid buds elongate, a lumen appears in the cranial part, beginning at each coelomic opening & it extend gradual to the caudal growing tips of the ducts. -At the 6 th week, the caudal end of each duct crosses the ventral aspect of the wolffian duct -The paired ducts continue to grow in a medial and caudal direction until they meet in the midline and become fused together in the urogenital septum -At the 8 th week, the duct extends caudally until it reaches the urogenital sinus of the now subdivided cloaca . The blind end of the duct projects into the posterior wall of the urogenital sinus as the Mullerian tubercle FATE -The site of invaginations forms the fimbriated ends of the fallopian tubes -The most cranial parts remain separate and form the fallopian tubes -The cranial point of fusion is the site of the future fundus of the uterus -The caudal segments fuse to form the uterus and part of the vagina -During the 4th month, proliferation of mesenchyme around the fused portion of the ducts leads to the development of the thick, muscular walls of the uterus and cervix. -The origin of the endocervical mucosa is controversial -Fluhmann postulated that the upward growth of the vaginal squamous epithelium, that he believed was of sinus origin, extended into the endocervix with subsequent columnar transformation. -Most authors favor a mullerian origin for the endocervical mucosa. -In any discussion of the embryology of the cervix, mention should be made of the importance of mesonephric remnants -These structures are found as minute tubules or canaliculi in the lateral cervical wall -They are lined with nonciliated simple columnar or cuboidal cells that have translucent cytoplasm and large, round nuclei. -Bizarre tumors, both benign and malignant, may arise from these remnants 2-DEVELOPMENT OF THE VAGINA -The vagina is formed from the lower end of the uterovaginal canal and the urogenital sinus -A solid vaginal cord results from proliferation of the cells at the caudal tip of the fused mullerian ducts -The cord gradually elongates to meet the bilateral endodermal evaginations (sinovaginal bulbs) -Sinovaginal bulbs extend cranially to fuse with the caudal end of the vaginal cord, forming vaginal plate -Subsequent canalization of the vaginal cord occurs, followed by epithelialization with cells derived mostly from endoderm of the urogenital sinus -The vagina develops under the influence of the mullerian ducts and estrogenic stimulation THEORIES: The origin of stratified squamous epithelium, remains in dispute. -Koff ( 1933) suggested that the lower 5th is derived from the urogenital sinus and the remainder from the transformed mullerian epithelium -Blumer (1957) proposed that the sinus and mullerian epithelium are histologicalty distinct and that the vaginal epithelium is derived completely from sinus epithelium -Forsberg, ( 1965) using histochemical methods, postulated a wolffian origin for the vaginal lining. -Parlmey ( 1974) stated that only the upper 1/3 of the vagina is formed from the mullerian ducts and that the lower vagina develops from the vaginal plate of the urogenital sinus 3-DEVELOPMENT OF THE GONADS -The development of the human gonads has a triple origin from: 1. The coelomic epithelium of the genital ridge. 2. Underlying mesoderm. 3. Primitive germ cells which come from an extragonadal source. DEVELOPMENT Indifferent stage -The gonad begins as a bulge on the medial aspect of the mesonephric ridge -There is proliferation of the cells of the coelomic epithelium beneath which is a concentration of mesenchymal cells. -Cords of coelomic epithelium projects into the substance of the developing gonad, breaking up the mesenchyme into loose strands interdigitating with these cords -During these early stages large numbers of big, primitive germ cells can lying between the cords -Gradually the germ cells become evident within the sex cords and the cells themselves are reduced in size. -The coelomic epithelium gives rise to the sex cords and the primitive mesenchymal tissue gives rise to the supporting tissue between. DIFFERENT stage -The gonad that is to become an ovary passes from the indifferent stage into one of differentiation and growth, and later, into the stage of follicle formation and stromal development -By 8 weeks cords beneath the outer cellular layer increase greatly in size and are sometimes called the secondary sex cords -The epithelial cells of the secondary cords are called the pregranulosa cells that undergo active proliferation and the germ cells becoming considerably reduced in size. This growth phase continues until some 14 weeks -The stage of follicle formation and stromal development follows. Fetal stromal cells develop from the mesenchyme in the region of the ovarian hilum at first and gradually spread peripherally until they permeate the whole ovary by 32-34 weeks -In the absence of the developing stroma, oocytes become encapsulated by a ring of pregranulosa cells -Disintegration of oocytes that do not succeed in encircling themselves with a capsule of pregranulosa cells -Once the stroma has spread throughout the primitive ovary, the primary follicles develop a capsule of stroma cells and the pregranulosa cells become granulosa cells. These cells secrete a fluid which is first retained within the cell membrane, but ultimately accumulates in the follicular cavity -The stroma cells of the follicular capsule differentiate into theca cells The Origin of Ova -It arise in the endoderm. Primitive germ cells in the epithelium of the yolk sac migrate along the endoderm of the yolk sac into the duct, into the site of the primitive gonad -The total population of germ cells reached a peak of 6, 800 000 at 5 months. By the time of birth the number had fallen to 2 000 000 of which 50% were atretic Development of External Genitalia -The primitive cloaca is subdivided by a transverse septum into an anterior urogenital portion and posterior rectal portion, begins at 4-5 weeks and is complete around 7 weeks -On the external surface of the embryo, the genital tubercle forms a conical projection encircling the anterior end of the cloacal membrane; the tubercle is present before cloacal division is complete -A medial pair of eminences, the genital folds, and a lateral pair, the genital swellings, are then formed by proliferation of mesoderm around the lower end of the urogenital sinus -The bladder and urethra are formed entirely from that portion of the vesicourethral division of the urogenital sinus above the Mullerian tubercle -The pelvic and phallic divisions of the sinus lead to the formation of the vestibule -The genital tubercle becomes the clitoris -The genital folds remain separate as the labia minora and the genital swellings enlarge to become the labia majora CLASSIFICATION OF UTEROVAGINAL ANOMALIES -The 1988 American Fertility Society (AFS) classification of uterovaginal anomalies comprises 4 groups CLASS I . DYSGENESIS OF THE MULLERIAN DUCTS CLASS II. DISORDERS OF VERTICAL FUSION OF THE MULLERIAN DUCTS CLASS III. DISORDERS OF LATERAL FUSION OF THE MULLERIAN DUCTS CLASS IV. UNUSUAL CONFIGURATIONS OF VERTICAL-LATERAL FUSION DEFECTS Class I. Dysgenesis of the Mullerian Ducts -It includes agenesis of the uterus and vagina (the Mayer-Rokitansky-Kuster-Hauser syndrome) Class II. Disorders of Vertical Fusion of the Mullerian Duct -Due to faults in the junction between the mullerian tubercles & the urogenital sinus. -They include: -Transverse vaginal septum: classified as either obstructed or unobstructed -Cervical agenesis or dysgenesis Class III. Disorders of Lateral Fusion of the Mullerian Ducts -They can be: Symmetric-unobstructed as with the double vagina, or Asymmetric-obstructed, as with unilateral vaginal obstruction it almost invariably are associated with absence of the ipsilateral kidney A-Asymmetric-obstructed with unilateral vaginal obstruction it is associated with absence of the ipsilateral kidney 1. Unicornuate uterus with a noncommunicating rudimentary horn 2. Unilateral obstruction of a cavity of a double uterus 3. Unilateral vaginal obstruction associated with double uterus B-Symmetric-unobstructed 1. Didelphic uterus a. Complete longitudinal vaginal septum b. Partial longitudinal vaginal septum c. No longitudinal vaginal septum 2. Septate uterus a. Complete I) Complete longitudinal vaginal septum 2) Partial longitudinal vaginal septum 3) No longitudinal vaginal septum b. Partial l ) Complete longitudinal vaginal septum 2) Partial longitudinal vaginal septum 3) No longitudinal vaginal septum 3. Bicornuate uterus a. Complete 1) Complete longitudinal vaginal septum 2) Partial longitudinal vaginal septum 3) No longitudinal vaginal septum b. Partial 1) Complete longitudinal vaginal septum 2) Partial longitudinal vaginal septum 3) No longitudinal vaginal septum 4. T-shaped uterine cavity (diethylstilbestrol related) 5. Unicornuate uterus a. With a rudimentary horn 1) With endometrial cavity a) Communicating b) Noncommunicating 2) Without endometrial cavity b. Without a rudimentary horn Class IV. Unusual Configurations of Vertical-Lateral Fusion Defects -This includes combinations of uterovaginal anomalies and other disorders -Unusual configurations of vertical-lateral fusion defects can be seen with abnormalities of the lower urinary tract. AMERICAN FERTILITY SOCIETY CLASSIFICATION OF MULLERIAN ANOMALIES Classification Anomaly Class I Segmental, mullerian agenesis-hypoplasia A. Vaginal B. Cervical C. Fundal D. Tubal E. Combined anomalies Class II Unicornuate A. Communicating B. Noncommunicating C. No cavity D. No horn Class III Didelphus Class IV Bicoruate A. Complete (division down to internal os) B. Partial Class V Septate A. Complete (septum to internal os) B. Partial Class Vl Arcuate Class Vll DES related DISORDERS OF VERTICAL FUSION I-TRANSVERSE VAGINAL SEPTUM -Incidences vary from 1 in 2000 to 1 in 70,000 -It is due to incomplete fusion between the mullerian duct & the urogenital sinus -It varies in thickness and can be located at any Ievel in the vagina -46 % occur in the upper vagina, 40% in the midvagina, and 14% in the lower vagina -It is associated with few urologic anomalies -There may be associated congenital anomalies as urinary tract anomalies, coarctation of the aorta, ASD, and malformations of the lumbar spine -The lower surface of the septum is covered by squamous epithelium. The upper surface is covered by glandular epithelium, which is transformed into squamous epithelium by a metaplasia after correction of the obstruction CLINICAL PICTURE @-In neonates & young adults -Hydrocolpos develops in the upper vagina & creates a large pelvic and lower abdominal mass -It displaces the bladder anteriorly & the ureters laterally leading to hydroureters & hydronephrosis, compresses the rectum and indirectly compress the vena cava and produce cardiorespiratory failure -The septum should be removed through a perineal approach @-In adults -Hematocolpos develop, symptoms include severe cyclic lower abdominal pain, no visible menstrual discharge if the septum is complete -Central lower abdominal and pelvic mass -A septum large enough to allow pregnancy to occur can cause dystocia during labor -Pelvic examination per rectum revealed a cervix and a normal-sized corpus Surgical Technique for a Transverse vaginal Septum -Transverse incision is made through the vault of the short vagina -A probe is introduced through the septum after a portion of the barrier has been separated by sharp and blunt dissection. -Palpation of a urethral catheter anteriorly and insertion of a double-gloved finger along the anterior wall of the rectum posteriorly so that the bladder and rectum can be avoided during this procedure -A soft foam rubber vaginal form covered with a sterile latex sheath can be placed in the vagina and removed in 10 days, it can be worn for 4 to 6 weeks until complete healing occurred HIGH TRANSVERSE VAGINAL SEPTUM -A space is created between the rectum and bladder to permit identification of the obstructed vagina -A probe is passed through the fundus of the uterus to tent out the vaginal septum and enable the surgeon to excise it from below and resect it safely. -The operator can probe the mass with an aspirating needle to identify old menstrual blood. -The upper vagina is then opened and the septum excised -If the distance between the septum and the upper vagina is too great an indwelling acrylic resin form consisting of a bulbous end and a channel through which menstrual blood can drain is placed into th vagina -Vaginal dilatation daily for 2 to 4 months to prevent contracture -An alternative may be a split-thickness graft to bridge the gap -Hurst and Rock described aspiration of the hematocolpos under ultrasound guidance to relieve the acute pain and delay surgery -Or continuous OCs to delay recurrence of hematocolpos. II-CONGENITAL ABSENCE OR DYSGENESIS OF THE CERVIX -It is an infrequent anomaly, it is often in association with absence of a portion or all of the vagina -Retention of menstrual blood initiates symptoms of cyclic lower abdominal pain -Diagnosis -Ultrasonography -Magnetic resonance imaging -Anatomic Variations of Congenital Cervical Anomalies I-Cervical aplasia (lack a uterine cervix) II-Cervical dysgenesis, can be described as 4 subtypes: 1. Intact cervical body with obstruction of the cervical os 2. Cervical body consisting of a fibrous band of variable length and 3. Stricture of the midportion of the cervix 4. Fragmentation of the cervix -Associated anomalies of the urinary tract are rare -Variable portions of the vagina can be atretic -Cervical obstruction is most often associated with a vagina of normal length. Treatment -Many authors recommend hysterectomy as an initial procedure for a patient with a functioning uterine corpus and congenital absence of the cervix and vagina -Hysterectomy can eliminate problems such as cryptomenorrhea, sepsis, endometriosis, and multiple operations. It may be possible to conserve the ovaries -Vaginoplasty with a split-thickness graft III-DISORDES OF LATERAL FUSION -Failures of lateral fusion of the two mullerian ducts cause vaginal anomalies that are grouped as obstructed or unobstructed. The Unobstructed Double Uterus (Bicornuate, Septate, or Didelphic Uterus) -Complete failure of medial fusion of the two mullerian ducts can result in complete duplication of the vagina, cervix, and uterus -Partial failure of fusion can result in a single vagina with a single or duplicate cervix and complete or partial duplication of the uterine corpus Historical Development of Surgical Procedures -Ruge, in 1882, first reported excision of a uterine septum in a woman who had suffered two pregnancy losses -Paul Strassmann of Berlin and later Erwin Strassmann, his son, began studies in 1936 & reported in 1953 Diagnosis of Uterine Anomalies -Presence of abnormal uterine contour during pregnancy, caused by a combination of fetal malpresentation and an anomalous uterus I -Ultrasonography, hysterography, or laparoscopy -Hystcrosalpingography -It must be taken at right angles to the axis of the uterus -It is best done under fluoroscopy -Double contour pelvic pneumoperitoneum hysterography -IVP Uterine Anomalies and Reproductive Faiture -The etiology remains unclear -Presence of a uterine septum can lead to abortion because of diminished intrauterine space for fetal growth or because of implantation of the placenta on a poorly vascularized septum. -Associated cervical incompetence, LPD, and distortion of the uterine milieu -The chance for a live born child increases with each pregnancy loss THE DIDELPHIC UTERUS -Diagnoses easily on routine pelvic examination by identification of two complete cervices and perhaps also a longitudinal vaginal septum (75%) -Patient with a longitudinal vaginal septum will usually, but not always, have a didelphic uterus -The didelphic uterus is associated with the best possibility of a successful pregnancy (fetal survival rate is 60% without metroplasty) -There is some increase in perinatal mortality, premature birth, breech presentation, and CS -It should not be considered an appropriate indication for metroplasty. Not only is this procedure technically difficult, but it can result in cervical incompetence or cervical stenosis. THE SEPTATE UTERUS -Most patients evaluated for repeated abortion and found to have a septate uterus -25% of patients have associated vaginal septum -Fetal survival rates are higher after septate uterus repair than after other repairs. 95% became pregnant postoperatively, and 77% delivered a liveborn child -AFS class VA uterus (a double cervix and uterine cavity with a single fundus) can result from a rotation abnormality during the descent of the mullerian ducts The dextrorotating mullerian ducts overrotate In every patient with a complete septate uterus, the left cervix is higher than the right Uterine Anomalies and Menstrual Difficulties -Dysmenorrhea & abnormal and heavy menstrual bleeding occur more frequently with any form of double uterus and relieved after unification operations -Dysmenorrhea and menorrhagia are inappropriate indications for uterine unification Uterine Anomalies and Infertility -Erwin Strassmann stated that primary infertility could be cured in 60% of patients with uterine anomaly -Non uterine causes of infertility must be ruled out before metroplasty -Even if no other cause of infertility, this may be an appropriate indication of metroplasty Surgical Technique for Uterine Unification 1-TRANSCERVICAL LYSIS OF THE UTERINE SEPTUM -The septum can be electrosurgically incised or resectoscope -A regimen of danazol or a GnRh agonist for 2 months to reduce the amount of endometrium that can obscure the surgeon's view during the procedure -The septum is electrosurgically incised by the cutting loupe of the resectoscope -If excessive bleeding, use of IU Foley catheter as tamponade & removed in 4-6 hour -Allow pregnancy after 2-months -Delivery may be vaginal 2-THE MODIFIED JONES METROPLASLY -The abdomen is opened through a transverse incision -To facilitate manipulation a traction suture is placed through the top of the septum -No attempt is made to stain the uterine cavity with methylene blue -Hypotensive anesthetic techniques in combination with the tourniquets will allow operation with negligible blood loss. -The uterine septum is surgically excised as a wedge. The incisions begin at the fundus of the uterus usually within 1 cm, and sometimes even less, of the insertion of the fallopian tubes -After the wedge is removed, the uterus is closed in three layers with interrupted stitches 2-0 nonreactive suture on an atraumatic tapered needle -The inner layer of stitches must include 1/3 of the thickness of the myometrium, the knot is tied within the endometrial cavity -The sutures are placed anterior first and then posterior. After the first few stitches are placed , the second layer is started to avoid tension -The third layer of stitches in the serosa both anteriorly and posteriorly -If a double cervix is present, the physician should not attempt to unify the cervix because an incompetent cervical os will be the result -Postoperative hysterogram films often show small dog ears that are left over tags from the original bifid condition of the uterus. It do not seem to interfere with function -Delay 4 to 6 months before attempt of pregnancy is advised 3-THE TOMPKINS PROCEDURE -A single median incision divides the uterine corpus and septum in half. -The incision is carried inferiorly until the endometrial cavity is reached. -Each Iateral septal half is then incised to within 1 cm of the tubes. -No septal tissue is removed. The myometrium is reapproximated -Advantages of the Tompkins technique: it is simpler, it conserves all myometrial tissue and leaves the uterotubal junction in a more normal & lateral position, and that it provides better results NB Cases of broad uterine septum can benefit from the wedge metroplasty. THE STRASSMANN MBTROPLASTY -It is not easily adapted to the septate uterus, it is the procedure of choice for unification of the two endometrial cavities of an externally divided uterus, both bicornuate and didelphic -The rectovesical ligament is attached anteriorly to the bladder, folds over and is attached between the uterine cornua, continues posteriorly in the cul de sac, and ends with its attachment to the anterior wall of the sigmoid and rectum. This ligament must be removed before a unification procedure can be performed -Tourniquets are used -The two uterine cornua are incised on their median sides along their longitudinal axes, deeply elongated to expose the uterine cavities -Inferiorly, the incision is carried far enough to join the two sides into a single endocervical canal. If it appears that a deeper incision will compromise the competence of the cervix, then a double cervical canal can be Ieft. -The suture technique for joining the two sides is the same as for the modified Jones procedure. -Uterine suspension can be performed if necessary -Presacral neurectomy should be considered only in patients with severe midline dysmenorrhea. -The cervix should be dilated for proper drainage from the uterine cavity -Ringer lactate containing heparin and corticosteroid can be used for peritoneal lavage throughout the procedure Cervical Incompetence Associated With a Double Uterus -When a patient with an anomalous uterus, becomes pregnant, she must be watched closely for evidence of cervical incompetence -Cervical cerclage is used mostly in patients with a partial bicornuate uterus -The cervical incompetence, not the uterine anomaly, is the proper indication for cerclage in these patients. -Some reproductive losses from a uterine anomaly might be prevented by cerclage -Delivery should be by CS if the cervix will cause dystocia as in a double or septate cervix Mode of Delivery After Metroplasty -The scar formed after unification is as strong as if not stronger than the scar formed after CS. why? Endomyometritis is a common complication after CS but is not a complication of uterine unification -Despite evidence that the uterine scar heals securely after unification operations, it is recommend to perform elective cesarean section in all patients after abdominal metroplasty DES Uterine Anomalies -The T shaped uterus is the most commonly seen -Cervical cerclage may be indicated in some patients. UNICORNUATE UTERUS -It can be present alone or with a rudimentary horn or bulb on the opposite side -The rudimentary anlage (uterine muscle bundle or bulb) can communicate directly with the unicornuate uterus. -Most rudimentary horns are noncommunicating (90%) Associated Anomalies -Urinary tract anomalies are often associated with a unicornuate uterus -On the side opposite the unicornuate uterus, there may be a horseshoe or a pelvic kidney or the kidney may bd hypoplastic or absent. -The orifice of the mullerian duct develops at about the level of the fourth thoracic vertebra (T4) in the embryo. The tip subsequently migrates along the course of the mullerian duct into the pelvis -Malpositions of the ovary and tube occurs Reproductive Performance -The reproductive performance is similar to that of the didelphic uterus -In cases of unicornuate uterus with a noncommunicating rudimentary uterine horn, there is danger of pregnancy in the rudimentary horn from transperitoneal migration of sperm or ovum from the opposite side -Signs and symptoms of ectopic pregnancy will develop with rupture of the horn. Rupture is associated with sudden and severe intraperitoneal hemorrhage and shock. -Perform cerclage as indicated LONGITUDINAL VAGINAL SEPTUM -Failure of fusion of the lower miillerian ducts that form the vagina can result in a vagina with a longitudinal septum -The septum can be partial or complete -In cases of didelphic uterus with a longitudinal vaginal septum, one uterine hemicorpus is usually better developed than the other. -The septum should be removed (when the patient is not pregnant) unless there is a contraindication. B-ASYMMETRIC OBSTRUCTION OF THE UTERUS OR VAGINA @-Unicornuate Uterus and Noncommunicating Uterine Anlage Containing Functional Endometrium -One mullerian duct develops normally, while the opposite mullerian duct fails to develop or develops incompletely, then a relatively normal unicornuate uterus is found on one side and the cervix, musculature, uterine cavity, endometrium, fallopian tube, blood supply, and ligamentous attachments are absent or hypoplastic to a varying degree on the other side. -If a rudimentary uterine horn does not communicate externally but have an endometrium-lined uterine cavity, the symptoms of obstructed menstruation may begin soon after menarche and severe dysmenorrhea will be present -Diagnosis should be made as soon as possible, because retrogrrade menstruation and pelvic endometriosis will develop @-Unilateral Obstruction of a Cavity of a Double Uterus -One cavity communicate with a cervix and the other did not. This could be an example of unilateral failure of cervical development -The patient complained of severe dysmenorrhea that appeared shortly after the menarche -A tense, cystic mass was palpable in the right half of the pelvis -The operation, described by Jones, consisted of making an incision through the anterior wall of the cystic right portion of the uterus. The entire septum was excised and the uterus was reconstructed by anastomosis of the two cavities. @-Double Uterus With Obstructed Hemivagina and Ipsilateral Renal Agenesis CLASS IV: UNUSUAL CONFIGURATIONS OF VERTICAL-LATERAL FUSION DEFECTS -Mullcrian duct anomalies can occur in association with a variety of other problems

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