The Incompetent Cervix 2

THE INCOMPETENT CERVIX PRESENTED BY DR T.K. NYENGIDIKI SENIOR REGISTRAR

INTRODUCTION • Repetitive reproductive disappointment • Frustration and Hopelessness, especially in this environment • Obstetrician faced with diagnostic difficulty because absence of strict diagnostic criteria and the anxiety of patient. • Relatively good results.

History • Classical presentation: -Recurrent mid trimester miscarriage -painless cervical dilatation -Rupture of membranes/expulsion of fetus • Preterm delivery • Elicit other predisposing factors • Diagnosis based on history is retrospective • One classical hx may also be suggestive

Investigations – non pregnant • Easy passage of a size 8 Hegar’s/Pratt’s dilator 15-17 • Foley’s catheter traction test - size 16 F balloon filled with 1ml of water (6mm) • Hysterosalpingography- dilated internal os > 6mm /widened isthmus( funnel/ Inverted Bishops cap) • Cervical compliance test (Zlatnik/ Burmeister)physical cervical assessment -has three parameter with the 1st two having scores from 0-2 and the last 0&1. -canal cannula ratio during hysteroscopy :< 1.5 , 1.5-1.9,>1.9.

continued -degree of force needed for insertion of a size 8 hegars’s dilator : Would not pass, little force or no force. -Catheter traction force < 700g> -Score range 0-5 -Higher scores more likely preterm delivery. • Cervical resistance index ( Anthony )-Simple strain gauge .Low in women with Hx of C.I. • Limitations – Hx suggestive of cervical incompetence.

Investigations -pregnant state • Weekly or forthnightly cervical assessment- softening effacement and dilatation • Serial ultrasound assessment of the lower uterine segment and cervix -length of the cervical canal: <2.5cm-risk -diameter of the internal os:>15 mm in the 1st trimester and > 20mm in the 2nd trimester -Prolapse of the fetal membrane thro os -All parameters are tested against stress : transfundal pressure, standing & coughing

Ultrasound continued

• Transvaginal ultrasound preferred -empty bladder - Identification of anatomical landmarks of the external and internal os TECHNICAL DIFFICULITIES 1.Cervix may be falsely normal if the bladder is over distended 2.Increased intrauterine pressure may give false impression of incompetence 3.Transducer angulation and pressure- artificial distortions 4. Contraction in the lower uterine segment can give a false impression 5.Cervical Os is dynamic

TREATMENT SURGICAL /MEDICAL SURGICAL -Cerclage procedures -Bridging procedure -Repair procedures -Sacrification procedures

CERCLAGE PROCEDURES • Most common • Principle -encircling the cervix with resilient band like material –purse string -maintaining the integrity of the internal os -Disallowing dilatation and effacement

VARIATIONS • Various methods exist but variations in - purse string material -differences in location -timing of the procedure Shirodkar’s procedure -Developed in 1955 -Vaginal approach to the cervix -Involved placement of a nonabsorble suture such as fascia lata, silk, nylon or mersilene tape around the cervix at the internal os. -The suture lies completely beneath vaginal and cervical mucosa.

Procedure -The junction between the anterior vaginal wall rugose with the smooth cervical mucosa is identified. -Transverse incision 2cm long is made at the junction and the bladder bluntly dissected until the uterovesical peritoneum is identified. -A atraumatic needle is passed submucosally in the cervix postero-anteriorly and knoted - The vaginal mucosa thereafter sutured anterioposteriorly

• Original idea was to leave stitch in situ and opt for caesarean section • Success rates 80% • McDonald Procedure -Most commonly used in this centre -In lithotomy position cervix is visualized using a sim’s speculum -The anterior and posterior lips held with sponge holding forceps -The junction between the anterior vaginal rugose and smooth cervical mucosa is identified- internal os -Placement of the suture is done just below this point -Four bites in the substance of the cervix are taken circumferentially purse string • First bit taken just before 12 o’clock and last just after 12 0’clock • The needle removed and the knotted up to four times with the knot left 2-3 cm long

Advantages over shirodkar • Greater technical ease • Fewer complications • Comparatively reduced incidence of C/section • No need for anaesthesia during removal

Complications of cerclage • • • • • • •

Infections Bleeding Anaesthetic complications Accidental rupture of fetal membranes Vesico vaginal fistula Premature labour Maternal death in the presence of sepsis due to prom

Bridging procedures • Involves bridging the opposite walls of the cervix with an unyielding material • Wurm’s procedure -Ist described by Rogers Wurm -Done in later pregnancy -Done after dislocation of a previous cerclage, partial cervical dilatation and partial effacement -Mattress sutures are placed at 12 & 6 o’ clock position and 3 & 9 o’clock position

• Baden and Baden procedure -1cm on the anterior and posterior surfaces of the cervix are debrided. -The two surfaces are sutured together

Repair procedures • Lash and Lash procedures -Believed there is a structural defect in the anterior cervix at the time of spontanous abortion. -wegded shaped segment of the area of defect is removed above the internal os -Remaining area is sutured with chromic catgut in two layer. -Success rate as reported by lash and lash 86%

Scarification procedures • Barnes Procedure -upper cervix is scarified circumferentially with electroconization -Increasing tensile strength of the cervix • Page procedures - external cervical scar in shape of long coil or spirals ALL ARE HISTORICAL!

Timing of procedure • Originally Shirodkar favoured preconception or post-conception placement. • Barter et al advocated 14-16 week placement -Technical ease of procedure -Chance for natural selection -

Emergency cerclage • Transcervical cerlage performed as an emergency • Preserve for patients without classical features incompetence • Patient experiencing features of incompetence in an index pregnancy :prolapse of membranes, cervical dilatation and effacement • Success rate lower • Higher incidence of infection • Prolonged hospital stay

Transabdominal cervical cerclage • Developed by Benson and Durfee in 1965 • Post conception/preconception • Abdomen entered via a midline or pfannenstiel’s incision • Cerclage stitch inserted at the cervico isthmic level via avascular window in the board ligament • Delivery is by abdominal route • Method preserved for patients with extremely short cervix, previously failed vaginal cerclage

The bulging membrane during emergency cerclage • Obstetrician is confronted with a bulging membranes during emergency cerclage • Management options -insertion of a foley’s catheter with 20ml balloon with the distal cut end inserted into the cervical canal and inflated. -use of 6-10 stay stitches attached to the edges of the cervix with the patient in deep trendelenburg position. Traction pushes back the membrane

Bulging membranes • Bladder distension with 1000mls of normal saline • Use of inflatable bags • Transabdominal amniocentesis with evacuation of 150mls of amniotic fluid.

Preoperative preparation • Vigorous preparation with use of chemical antiseptics should be discouraged • Copious irrigation of vagina under direct vision normal saline or ringer’s lactate. Povidine iodine preparation also advised. • Microbial culture - cervical/urine culture

Anaesthesia • Various forms of anaesthesia had been used • Inhalational, spinal and general anaesthesia. • Different views • opponents of GA –excessive coughing • Proponents of inhalational anaesthesia - relaxation of the uterus

Post operative instruction • Antibiotics -cefoxitin, amoxicillin, ampicillin and clindamycin, erythromycin. • Tocolytics -controversial except for patients with uterine irritability. • Bed rest advised for the 1st 24 hours followed by mobilization and activity • Discharge after a couple of days advised - studies have found no benefit for staying more than one week •

Removal of cerclage • Timing: usually b/w 37-38 weeks • Earlier removal -excessive vaginal bleeding -intrauterine fetal death -persistent uterine contraction -Rupture of fetal membranes

Medical management • Hodge pessaries -Developed by Vitsky in 1961 -properly placed pessaries can cause cervix to point posteriorly -alleviate some of the direct pressure on the cervix -preventing descent of the fetal head -Best results obtained if inserted at 14 weeks -Success rate 92% -Removal not later than 38 weeks

Medical management cont. • Baylor Balloon -Proposed in 1972 -Double silicon plastic cuff inserted on cervix to act as cuff. • Progesterone -Reduces uterine tone -Studies by Sharma showed a 92% success rate when it used alone compared to 82% with surgery and 47% -surgery alone

Advice at discharge • Avoid coitus • Avoid insertion of any substance into vagina • Gradually resume normal activity but avoid strenuous activity • Report any increased vaginal discharge, vaginal or back pressure or pelvic cramps • Follow routine antenatal clinic attendance but may need to be examined forthnightly to determine the integrity of the cerclage