Arthur Greenwood, MD

CLINICAL PELVIMETRY AND THE FORCEPS VAGINAL DELIVERY

CLINICAL PELVIMETRY OBJECTIVES• Understand the importance of Clinical Pelvimetry and its role in modern day obstetrics

• Know the steps for a thorough vaginal exam

• Be better able to describe the pelvis in clinical terms

• Be better able to identify the type of pelvis your patient has and understand the significance

• Recognize the type of pelvis at increased risk for third and fourth degree perineal lacerations

FORCEPS ASSISTED VAGINAL DELIVERY OBJECTIVES• Know the anatomy of forceps and be able to distinguish different types of forceps and

their uses

• Understand the indications for a trial of forceps

• Know how to check for proper application of forceps

• Understand the potential use of forceps during cesarean deliveries

• Recognize the steps our program needs to take to ensure that Wake Forest continues to be a program where residents graduate with the knowledge to perform FAVD

THE CALDWELL-MALLOY CLASSIFICATION (1933, 1934)

KEY ANATOMIC FEATURES OF THE TRUE PELVIS• Sacral promontory

• Retropubic angle

• Width of the sacrosciatic notch

• Anterior surface of the sacrum

• Ischial spines and tuberosities

• Inner surface of the ischium

• Suprapubic arch

• Descending pubic rami

• Coccyx

THE INLET• Diagonal Conjugate – distance from the sacral promontory to the to the inferior margin of

the symphysis pubis

• OC = DC-1.5cm

• Contracted: OC <10.5cm

THE INLET: THE RETROPUBIC ANGLE

• A.K..A. the forepelvis in older textbooks

• Performed by placing 2 fingers under the pubic arch, dropping wrist, and palpating the symphysis and both superior pubic rami

• ANDROID PELVIS: sharp and acute

• PLATYPELOID PELVIS: flat nearly 180degrees like a blackboard

• GYNECOID PELVIS: flat in the midline, curves gently backward laterally

• ANTHROPOID PELVIS: backward curve is detected earlier and curves back more sharply

THE MIDPLANE• Lower sacral vertebrae

• Sacrum: Flat or hollow (flat is less common)

THE MIDPLANE

• Sacrospinous ligament

• Less than 2 fingerbreadths implies a narrow sacrosciatic notch

• A 3 fingerbreadth ligament directed more laterally than anteriorly suggests a platypeloid pelvis

• Anthropoid pelvis also is 3 fingerbreadths or more directed more anteriorly than laterally

THE MIDPLANE• Ischial spines: prominent, blunt or average

THE MIDPLANE: BISPINOUS DIAMETER

• Not readily assessed clinically

• Separate examining fingers as wide as possible

• In the rare contracted pelvis one may be able to span the distance between spines

THE MIDPLANE• Ischial spines: prominent, blunt or average

• Slope of the pelvic sidewall

• Straight

• Convergent: Funnel shaped or android pelvis

• Divergent: “Blunderbuss” pelvis

THE MIDPLANE: “BLUNDERBUSS”

THE OUTLET• Coccyx: The shape and mobility should be described

• Suprapubic angle

• Gynecoid pelvis: suprapubic angle > 90 degrees. Suprpubic arch is characterized as “Norman”

• Android pelvis: exam fingers will be forced to overlap at the top of the “Gothic” arch

• Bituberous diameter (BTD)

• Can be measured with a fist externally

• An narrow BTD (<8cm) increases the risk of deep perineal lacerations or extension of an episiotomy (odds ratio of 15)

• Narrow BTD is strongly indicative of an android pelvis

• Can also be found in an anthropoid pelvis

CLINICAL PELVIMETRY• Sacral promontory

• Retropubic angle

• Width of the sacrosciatic notch

• Anterior surface of the sacrum

• Ischial spines and tuberosities

• Inner surface of the ischium

• Suprapubic arch

• Descending pubic rami

• Coccyx

FORCEPS ASSISTED VAGINAL DELIVERY

EDWARD DENNON’S FUNDAMENTAL RULES• FAVD must be considered a surgical procedure

• It should be done by a trained, coordinated operating team including an operator, assistant, anesthesiologist, scrub and circulation nurse

• Fully equipped room to handle any emergency

THE INTERN

• “The intern, before being allowed to perform a forceps delivery operation, should be given a series of painstaking lectures on the subject. He should be drilled in detail, repeatedly, on the manikin and he should assist at numerous operations which, in turn, should be reviewed on the manikin.”

ANATOMY OF FORCEPS

THE BLADEFenestrated

Pseudofenestrated

THE SHANK

Simpson type forceps have parallel separated shanks resulting in a long tapering cephalic curve for the long molded head.

Elliot type forceps have overlapping shanks for the rounded unmolded head

THE LOCK

• French lock (top left )• English lock (top right )• German lock (middle left )• Sliding rock (middle right )• Pivot lock (bottom )

THE HANDLE• Sliding Lock

THE HANDLE• Sliding Lock

THE HANDLE• Sliding Lock

SLIDING LOCK• Luikart s Keilands Bartons

LUIKARTS• Sliding Lock

• Allows for correction of asynclitism

• Psuedofenestrated blades

• Overlapping shanks

• Puts less tension on the perinium

PSEUDOFENESTRATED BLADES

TUCKER-MCLANE• Nonfenestrated blades

• Overlapping shanks

• English lock

• Excellent for the round nonmolded head (multiparous)

MCLANE-LUIKART• These are Tucker Mclane forceps with the Luikart modification (pseudofenestrated

blades)

SIMPSON• Fenestrated blades

• Parallel shanks

• English lock

• Excellent for the molded head

LUIKART SIMPSON• Simpson forceps with the Luikart modification (pseudofenestration)

• Excellent for the molded head

BILL’S AXIS TRACTION BAR

BILL’S AXIS TRACTION BAR WITH TUCKER-MCLANE FORCEPS

DEWEE FORCEPS WITH BUILT IN AXIS TRACTION BAR

DEWEE FORCEPS WITH BUILT IN AXIS TRACTION BAR

BARTON FORCEPS

BARTON FORCEPS

BILL’S AXIS TRACTION BAR WITH TUCKER-MCLANE FORCEPS

LAUFE FORCEPS

LAUFE FORCEPS

LAUFE PIPERS

LAUFE PIPERS

INDICATION FOR OPERATIVE VAGINAL DELIVERY

• No indication for operative vaginal delivery is absolute• Prolonged second stage

• Nulliparous women: 3 hours with regional anesthesia, or 2 hours without

• Multiparous women: 2 hours with regional anesthesia, or 1 hour without

• Suspicion of immediate or potential fetal compromise

• Shortening of the second stage for maternal benefit

ACOG Practice Bulletin NO. 17

SUSPICION OF IMMEDIATE OR POTENTIAL FETAL COMPROMISE

• 20 y/o G1 at 37wks EGA undergoing IOL for mild Pre E

• After 30 minutes of second stage labor, FHR tracing shows recurrent variable decelerations with increasing depth and minimal variability.

• Category II (indeterminate) tracing

• Ancillary test to ensure fetal well being or an attempt, for intrauterine resuscitation

• Expedited delivery is a valid option to avoid deterioration to Cat III and risk of asphyxia

PREREQUISITES FOR FAVD• Complete cervical dilation

• Ruptured membranes

• Head engaged

• Position and station known

• Clinically adequate pelvis

• Assessment of fetopelvic relationship known

• Adequate anesthesia

• Patient properly positioned

• Perineal body evaluated (consider episiotomy and type)

• Empty bladder/rectum

• Cesarean delivery capability

MORBIDITY ASSOCIATED WITH SECOND STAGE CESAREAN DELIVERY• Increased risk of maternal hemorrhage

• Prolonged hospital stay

• Increased risk of bladder trauma

• Extensions of uterine incision into broad ligament and vessels

Murphy, BMJ 2006; 333:613-4

OUTLET FORCEPS• Scalp is visible at the introitus without separating the labia

• Fetal skull has reached the pelvic floor

• Sagital suture is in an anteroposterior diameter or right or left occiput anterior or posterior position

• Fetal head is at or on the perineum

• Rotation does not exceed 45 degrees

LOW, MID AND HIGH FORCEPS

• Low forceps• Leading point of the fetal skull is at station +2cm or more and not on the pelvic floor.

• Rotation is 45 degrees or less (LOA,ROA, LOP, ROP)

• Rotation is greater than 45 degrees

• Midforceps• Station is above +2 cm but the head is engaged

• High Forceps• Not included in classification

ELECTIVE LOW FORCEPS• Carmona and associates

• Randomized trial comparing elective low –forceps delivery with spontaneous vaginal delivery in 50 term patients

• No significant immediate differences in maternal or neonatal outcomes

• Mean time to delivery was shorter (10.2 min versus 18 min)

• Cord pH higher (7.27 versus 7.23)

Am J Obstet Gynecol 173:55, 1995

ACOG PRACTICE BULLETIN #17, JUNE 2000, REAFFIRMED 2009

• Level A• Forceps and Vacuum are acceptable and safe instruments for operative vaginal delivery.

Operator experience should determine which instrument to use

• Vacuum is associated with increased incidence of neonatal cephalohematomas, retinal hemorrhages, and jaundice when compared with forceps delivery

• Level B• Minimize duration of vacuum application

• Midforceps operations should be considered an appropriate procedure to teach and to use under correct circumstances by an adequately trained individual

• Incidence of intracranial hemorrhage is highest with cesarean following failed vacuum or forceps. The combination of vacuum and forceps has a similar incidence. Operative vaginal delivery should not be attempted when the probability of success is low

ACOG PRACTICE BULLETIN #17, JUNE 2000, REAFFIRMED 2009

• Level C• Operative vaginal delivery is not contraindicated in cases of suspected macrosomia or

prolonged labor; however caution should be used because the risk of shoulder dystocia increases with these conditions

• Neonatal care providers should be made aware of the mode of delivery in order to observe for potential complications associated with operative vaginal delivery

APPLICATIONOF FORCEPS• The posterior blade or left blade for

direct OA/OP is applied first

APPLICATIONOF FORCEPS

APPLICATIONOF FORCEPS• Posterior fontanelle is

one finger’s breadth anterior to the plane of the shanks

• The sagital suture is perpindicular to the plane of the shanks

• Not more than the tip of one finger can inserted into the fenestration in advance of the head

PAJOT-SAXTORPH MANEUVER

MODIFIED RITGEN

TEACHING LAUFE-PIPER FORCEPS TECHNIQUE AT CESAREAN DELIVERY• University of Texas Galveston, Locksmith, Yeomans, Hankins et al

• Objective: To present a method of teaching forceps during cesarean breech deliveries using Laufe-Piper forceps and to evaluate its usefulness

• For several years residents were taught this method of delivery. To assess residents experience, recent graduates and 3 rd and 4th year residents completed a survey as well as matched controls from other programs were this was not taught.

• Responses from 32 (74%) study subjects and 63 (71%) controls.

• Study subjects rated themselves more comfortable using piper forceps and noted greater annual use of forceps for vertex deliveries.

• CONCLUSION: Laufe-Pipers can be used for cesarean delivery of breech-presenting infants. This practice promotes confidence and skill for their use at vaginal delivery.

J Reprod Med 2001 May; 46(5):457-61

LAUFE PIPERS

TEACHING LAUFE-PIPER FORCEPS TECHNIQUE AT CESAREAN DELIVERY

PIPERS TO THE AFTERCOMING HEAD

TEACHING LAUFE-PIPER FORCEPS TECHNIQUE AT CESAREAN DELIVERY• No maternal or neonatal complications have been attributed to this practice

• Because the Laufe-pipers lack handles they are shorter than conventional pipers; this offers a distinct advantage at cesarean

• The similarities of application of forceps at cesarean provide practice for vaginal breech application of pipers to the aftercoming head

• After application, head flexion is ensured by elevating the shanks slightly and lowering the infants body against them.

• Extraction is accomplished by pulling outward and raising the grips

TEACHING LAUFE-PIPER FORCEPS TECHNIQUE AT CESAREAN DELIVERY• Vaginal breech delivery is rarely performed

• In an emergency situation it may be the best option

• It may be used for breech extraction of twin B

• Because the rarity of breech deliveries in residency, educational opportunities are sparse

• Laufe-Pipers for breech cesarean has been found to be of educational benefit

BABY SIMPSONS AT CESAREAN• We have forceps in every cesarean tray

• Please see Williams Obstertrics, chapter on Forceps through the Coy Carpenter Library and watch the animated video forceps during cesarean.

• Excellent option for the floating head

• Excellent option for the difficult delivery

RESIDENT GENDER• >350,000 deliveries

• By >800 OBGYN residents in the US from 1994-1998

• Percentage of total deliveries performed with forceps during residency was higher among male residents

• Percentage of vaginal deliveries with forceps was also higher

• Percentage of overall operative vaginal deliveries was significantly higher for males

• Percentage of vacuum deliveries did not vary by gender

Am J Obstet Gynecol. 2000 May;182(5):1050-1

CONCLUSION• Proactive residents

• Proactive faculty

• Include Forceps as part of the Summer Lecture Series

• Include a hands on forceps workshop as part of that series

• Obtain Laufe-Pipers and have them available for every breech cesarean delivery

• Incorporate Clinical Pelvimetry into our daily practice