Prof. M.C.BansalMBBS., MS., FICOG., MICOG.Founder Principal & Controller,Jhalawar Medical College & Hospital Jjalawar.MGMC & Hospital , sitapura ., Jaipur
AnatomyA. Pelvic floor: Pelvic floor is a muscular diaphragm that separates the pelvic cavity above from the perineal space below. It is formed by the levator ani and coccygeus muscles, and is covered by parietal fascia. The levator ani muscles on either side arise from posterior surface of pubic symphysis, the white line over fascia covering obturator internus and ischial spine.
The levators sweep from the lateral pelvic wall downwards and medially to fuse with the opposite side in the midline and form a pubo-coccygeal raphe. Fibres of Levators are inserted from before backwards and fuse with muscle fibres of urethra, the vaginal walls, perineal body, anal canal, anococcygeal body and the lateral borders of coccyx. Functions: To support the pelvic viscera. To maintain effective intra-abdominal pressure. To facilitate anterior rotation and downward and forward propulsion of the presenting part during parturition. Serves as a support and voluntary sphicter of urethra, vagina and anal canal. There are gaps in pelvic floor:- 1. Urogenital hiatus- anterior gap through which urethra and vagina pass. 2. Rectal hiatus- posterior gap through which anal canal passes.
B. Urogenital diaphragm: The urogenital diaphragm is external to pelvic diaphragm and includes the triangular area between the ischial tuberosities and the symphysis. It is made up of deep transverse perineal muscles, sphincter urethrae and internal and external fascial coverings.
Anatomy contn..C. Perineum: Perineum is a diamond-shaped space that lies below the pelvic floor.it is bounded by: Superiorly: pelvic floor Laterally: the pelvic outlet consisting of subpubic angle, ischiopubic rami, ischial tuerosities, sacrotuberous ligaments and coccyx Inferiorly: skin and fascia
This area is divided into two triangles by transverse muscles of perineum and base of urogenital diaphragm: Anteriorly- Urogenital triangle. Posteriorly- Anal triangle Most of the support of perineum is provided by pelvic and urogenital diaphragms.
Perineal Body: The median raphe of levator ani between the anus and vagina, is reinforced by the central tendon of the perineum. Bulbocavernosus, superficial transverse perineal and external anal sphincter muscles also converge on the central tendon. These muscles contribute to perineal body, which provides much support to perineum.
Blood supply to perineum: Major blood supply is by internal pudental artery and its branches- inferior rectal artery and posterior labial artery. Posterior labial Inferior rectal
Nerve Supply is primarily via pudendal nerve(S2,S3,S4) and its branches.
Causes and Predisposing Factors: Lacerations of perineum are the result of overstreching or too rapid streching of the tissues, especially if they are poorly extensile and rigid. Perineal injuries are more common in primigravida than multigravida. Obstetric injuries: Malpresentations such as breech Contracted pelvic outlet spontaneous labour operative vaginal deliveries( forceps or vaccum) Macrosomic babies Non-obstetric injuries: rape, molestation, fall, accidental injuries like RTA, bull horn injuries etc.
Degrees of Perineal tear: First degree- limited to vaginal mucosa and skin of the introitus. Second degree- extends to the fascia and muscles of the perineal body. Third degree- trauma involves the anal sphincter. Fourth degree - extends into the rectal lumen, through the rectal mucosa. A rare type of tear is central tear of the perineum when the head penetrates first through the posterior vaginal wall, then through the perineal body and appears through the skin of the perineum. It usually occurs in patients with contracted outlet.
Symptomatology: Immediate: Bleeding Traumatic PPH - hemorrhagic shock. Perineal Pain Perineal hematoma Urinary retention due to painful perineum Urinary incontinence Anorectal dysfunctions like fecal incontinence Delayed: 1. Infected perineum- perineal abscess 2. Uterovaginal prolapse 3. Urinary incontinence (stress and urinary fistula) 4. Fecal incontinence ( rectovaginal fistula) 5. Dyspareunia 6. Feeling of slack vagina during coitus Bleeding Disruption of anatomical continuity
How to recognize: Put the patient in extended lithotomy position. Arrange proper spottless bright light. Arrange for vaginal pads instruments like ant. and post. vaginal retractors , urinary cathter, sponge holders, curved and straight artery clamps. Vulva should be examined stepwise right from clitoris to the anus downwards, laterally paraclitoral, paraurethral, paravaginal and pararectal skin and muscles in every case after delivery. Perineal tears may be associated with high vaginal circular tears and tears in the fornix and cervix. One should suspect traumatic PPH due to perineal tears when continuous bleeding p/v persisting even after delivery of placenta when uterus is contracted and retracted. All lacerations exceeding half inch in depth should be immediately repaired and individual bleeder should be ligated separately.
Prevention: Timely episiotomy should be given in all primigravida, vacuum and forceps delivery, breech delivery and breech extraction done after IPV, rigid perineum in multigravida or previous cases with history of perineal tears. Proper support of perineum at the time of crowning and expulsion of head.
Repair Lacerations should be repaired immediately if possible, and certainly within 24 hours of delivery. First step is to define the limits of the lacerations, which includes vagina as well as perineum. Best suture material is catgut for the vagina and buried sutures; and fine mono-filament nylon for skin. As accurate an approximation as possible of all the tissues should be secured and no dead spaces are left. Method: The vaginal tear is repaired first, care being taken to reach upper limit and to include the underlying fascia as well as vaginal mucosa in the sutures.
Complications if left untreated: Infection Hemorrhagic Shock Cosmetic disadvantage 3rd and 4th degree tears if left untreated may lead to fecal incontinence.
Chronic perineal laceration In most cases of Chronic perineal laceration with long standing disruption of anal sphincter complex, classical symptoms are progressive loss of control of gas and faeces from anus. If the puborectalis muscle is left intact and is well innervated and functional, it can provide sufficient muscular contraction to permit control of faeces when the patient is constipated and when the stool is of normal consistency. Such patients quickly learn this and remain in a constipated state to decrease their symptoms.
Repair ofchronic complete perineallaceration1. Layered method of repair2. Warren flap procedure3. Noble-Mangert-Fish operation If the anorectal mucosa is intact and the injury is largely limited to the anal sphincter complex and perineal body, repair consists of anal sphinteroplasty with extensive perineorrhaphy
1. Layered method of repair:A. A transverse or crescent perineal incision is used at the junction of posterior vaginal wall and anal mucosa. lateral margins of incision are extended to the region of perineal dimple created by the retracted external sphincter. A midline incision is made along the lower half of the posterior vaginal wall.B. Anterior rectal wall is separated in the midline from the posterior vaginal wall with careful scissors dissection. Dissection is carried laterally till the region of external anal sphinter.
C. All scar tissue is excised from the margins of the anorectal mucosa , and the defect in anal mucosa is closed using a continuous or interrupted suture of 3-0 delayed absorbable material. A submucosally placed suture is ideal. After mucosal margins are approximated, a second supporting layer inverts the initial mucosal suture line, this is internal anal sphincter identified as white smooth layer of tissue between the anorectal mucosal closure and external anal sphincter. This muscle is responsible for most of the resting pressure in the anal canal. it also serves to imbricate and isolate the mucosal layer and take tension off it helping it heal and seal against infection.
D. External anal sphincteroplasty is done:In approximation-type external anal sphincteroplasty, exetrnal anal sphincter ends are completely trimmed of scar tissue and united in the midline with interrupted 0 or 2-0 delayed absorbable sutures ( such as monofilament polydioxanone). 4-5 sutures are used to approximate the sphincter muscle.In overlapping approach to the external anal sphincter, the scarred ends of the torn sphinter are used to hold the sutures that reconstitute the circumferential sphincter. The ends are widely mobilized with the scar tissue left on, taking care not to dissect beyond the 3 and 9-o’clock position bacause pudendal innervation enters laterally. The external sphincter is brought together over the repaired internal sphinter with two rows of two horizontal mattress sutures of delayed absorbable type.
E. Restoration of narrower gental hiatus by bringing the puborectalis muscles closer together. Dissection is carried out laterally to the fascia overlying the medial border of puborectalis. This fascia is brought together by a series of interrupted , delayed- absorbable sutures. It is extended till midportion of vagina to produce excellent anatomical support to rectum and anal canal.F. Further support to perineal body is provided by bringing together the disrupted ends of the superficial transverse perineal muscles and bulbocavernosus. redundant vaginal mucosa is excised and remaining mucosa is approximated in midline with a continuous 2-0 or 3-0 delayed absorbable suture. It followed by subcuticular closure of perineal skin.
(II). Warren Flap Operation for complete third degree tearA. An inverted V-shaped incision is made in the posterior vaginal mucosa, outlining the flap that is to be turned down. The lower ends ot incision should be just lateral to the dimples caused by retracted sphincter ends. The length of the flap should measure a minimum of 3 cm to provide sufficiet vaginal mucosa.B. Taking care not tot injure the bowel the bowel wall, the flap of mucosa is dissected free from above downwards, stopping short of the margin between the vaginal and anal mucosa. The flap is turned down to hang over the anus.
C. External anal sphincter ends are then dissected free and approximation or overlapping type external anal sphincteroplasty is then performed.D. The fascia overlying the medial aspect of puborectalis muscles is identified and is brought together with a series of interrupted sutures using 0 or 2-0 delayed absorbable sutures.E. Margins of vaginal mucosa and graft are approximated in the midline by a continuous locking stich of 3-0 delayed absorbable suture.
III. Noble Procedure:A. The torn perineal anal and rectal tissues in patient with complete perineal tear form form a ‘butterfly appearence’ across the perineum. The wings of butterfly are the dimples of the retracted ends of the external anal sphincter. The initial incision is outlined around the margins of this area following the margin of anal mucosa along tha anatomical defect in rectovaginal septum.B. Sharp dissection is done to separate tha anal wall from vaginal mucosa. External anal sphincter remnants are sharply mobilized and separated from underlying anal wall.
C. Ends of external anal sphinter are approximated end to end or overlapping.D. Genital hiatus is narrowed by bringing puborectalis muscles closer .
E. Transverse perineal muscles and inferior margins of bulbocavernosus are reapproximated.vaginal mucosa is trimmed, if necessary and margins of posterior vaginal wall are approximated with continuous locking stich of 3-0 delayed absorbable suture. This suture is carried over the perineal body as a subcuticular stich and perianal skin is approximated in midline. Excess anal mucosa is trimmed and vertical mattress sutures of 3-0 delayed absorbable suture are used to approximate the broad surface of anal submucosa to perianal skin.
Dehiscence of a vaginal laceration repair should be evaluated for infection, irrigated, and debrided of necrotic tissue. Sitz baths should be used liberally. If discovered in the first 2–3 days after delivery, the wound can be resutured; however, if the tissue is friable or has evidence of infection, a secondary repair should be delayed for 6–8 weeks. Antibiotics should be utilized if infection is noted
Why is an episiotomy only performedwith clear indication? Third and fourth degree lacerations and anal incontinence of stool or flatus are more common with an episiotomy than with a spontaneous laceration What muscles are affected by seconddegree lacerations? Bulbocavernous and ischiocavernous Laterally Superficial transverse perineal muscle.
The prevalence of clinically recognized anal sphincter lacerations varies widely and has been reported to occur in 0.6% to 20.0% of vaginal deliveries, with higher rates documented after operative vaginal delivery. the perineal skin may be intact with an underlying muscle tear not visible. Risk factors for both occult and clinically recognized anal sphincter disruption include midline episiotomy, operative vaginal delivery (both forceps and vacuum), persistent occiputo- posterior head position, prolonged second stage of labor (>2 hours), and delivery of macrosomic infants.