References: Obstetric Anal Damage; Volume 3 Issue 8

1. AUTHOR	Kamm-M-A.
INSTITUTION	St Mark's Hospital, London, UK.
TITLE	Obstetric damage and faecal incontinence (see comments).
SOURCE	Lancet 1994 Sep 10, VOL: 344 (8924), P: 730-3, ISSN: 0140-6736 25 Refs.
CM	Comment in: Lancet 1994 Nov 5; 344(8932):1301; Comment in: Lancet 1994 Nov 19; 344(8934):1435.
ABSTRACT	Anal incontinence for gas or faeces affects up to 11% of adults, and occurs frequently in 2%. The commonest cause in healthy women is unrecognised damage to the anal sphincter during childbirth; 13% of women having their first vaginal delivery develop incontinence or urgency, and 30% have structural changes shown by anal endosonography. The commonest predisposing cause of damage is the use of forceps. When a third-degree tear occurs, 85% of women have persistent structural sphincter defects and 50% remain symptomatic despite primary repair after delivery. Structural damage associated with childbirth is more important than neurological factors. The characterisation of this sphincter damage has led to improved treatment, including successful surgical repair. Author.

2. AUTHOR	Henry-M-M.
INSTITUTION	Department of Obstetrics and Gynaecology, Central Middlesex Hospital, London, UK.
TITLE	The role of pudendal nerve innervation in female pelvic floor function.
SOURCE	Curr-Opin-Obstet-Gynecol 1994 Aug, VOL: 6 (4), P: 324-5, ISSN: 1040-872X.
ABSTRACT	The assessment of motor conduction along the pudendal nerve is an accurate objective measure of pudendal nerve function. Measurement of its latency (that is the time interval between electrical stimulation of the nerve and induced contraction of the external anal sphincter) has been demonstrated to be abnormally long following vaginal delivery, particularly if the delivery was associated with a heavy fetus or a prolonged second stage of labor. The significance of pudendal neuropathy and its relationship to abnormal degrees of descent of the pelvic floor have also been examined in this review. Author.

3. AUTHOR	Toglia-M-R, DeLancey-J-O.
INSTITUTION	Division of Surgical Gynecology, State University of New York at Stony Brook, USA.
TITLE	Anal incontinence and the obstetrician-gynecologist.
SOURCE	Obstet-Gynecol 1994 Oct, VOL: 84 (4 Pt 2), P: 731-40, ISSN: 0029-7844 53 Refs.
ABSTRACT	OBJECTIVE: To gather, synthesize, and present useful scientific information concerning the anal continence mechanism that will aid obstetrician-gynecologists in managing vaginal birth and evaluating women with anal incontinence not caused by disruption of the external anal sphincter. DATA SOURCES: Sources included a Medline search and reference lists of relevant articles and standard textbooks. METHODS OF STUDY SELECTION: Articles were identified that contained scientific data on the pathophysiology of anal incontinence, the influence of vaginal delivery on the continence mechanism, and therapeutic measures. Only those presenting original research results were included. Studies concerned exclusively with surgical management of the ruptured perineum were excluded. DATA EXTRACTION AND SYNTHESIS: All articles were reviewed and the physiologic data summarized. These findings were grouped by their relevance to each anatomical or physiologic issue involving anal incontinence and by whether they considered the issue of injury at the time of vaginal delivery. The data were then assembled into a functionally oriented overview of the continence mechanism. The subject of injury at the time of vaginal delivery was considered separately against a background of continence pathophysiology. CONCLUSION: Vaginal delivery may initiate damage to the continence mechanism by direct injury to the pelvic floor muscles, damage to their motor innervation, or both. Additional denervation may occur with aging, resulting in a functional disability many years after the initial trauma. These factors should be kept in mind when conducting vaginal birth and planning therapy for anal incontinence. Author.

4. AUTHOR	Sultan-A-H, Stanton-S-L.
INSTITUTION	Department of Urogynaecology, St George's Hospital, London, UK.
TITLE	Occult obstetric trauma and anal incontinence.
SOURCE	Eur-J-Gastroenterol-Hepatol 1997 May, VOL: 9 (5), P: 423-7, ISSN: 0954-691X 32 Refs.
ABSTRACT	Obstetric trauma is by far the commonest cause of anal incontinence in women. Denervation and reinnervation of the pelvic floor and anal sphincter following vaginal delivery has been previously demonstrated. The advent of anal endosonography, however, has enabled the identification of occult anal sphincter defects following vaginal delivery. It is now possible to identify risk factors and change obstetric practice accordingly so as to minimize anorectal morbidity. Author.

5. AUTHOR	Wynne-J-M, Myles-J-L, Jones-I, Sapsford-R, Young-R-E, Hattam-A, Cantamessa-S-E.
INSTITUTION	University Department of Obstetrics and Gynaecology, Mater Hospital, South Brisbane, Australia.
TITLE	Disturbed anal sphincter function following vaginal delivery.
SOURCE	Gut 1996 Jul, VOL: 39 (1), P: 120-4, ISSN: 0017-5749.
ABSTRACT	BACKGROUND: Recently interest in idiopathic (neurogenic) faecal incontinence has swung from denervation of the external anal sphincter to the internal sphincter. AIMS: To evaluate the effects of vaginal delivery on the internal sphincter. SUBJECTS: 1372 mothers were studied antenatally and 1202 were accepted into the study. METHODS: Sphincter pressures were measured antenatally, in the early postnatal period, and six to 10 weeks later in selected patients. RESULTS: 755 of 1202 subjects assessed antenatally were primiparous women and 447 multiparous women. Some 320 previous spontaneous vaginal deliveries (SVD) (mean 59 mm Hg) and 67 previous forceps deliveries (mean 58 mm Hg) had lower resting pressures than 755 primiparous women (mean 66 mm Hg) (p < 0.01). A total of 493 subjects were reassessed postnatally. There were 372 SVDs, 47 vacuum extractions, 20 forceps, and 54 caesarean deliveries. All vaginal deliveries but not caesarean sections dropped their resting anal pressures from antenatal values (p < 0.001). Some 227 first SVDs had a much greater fall than 145 subsequent SVDs. In 162 subjects who had undergone their first vaginal delivery and who were followed up there was some recovery but the resting pressures were still lowered at six to 10 weeks post partum. CONCLUSIONS: The first vaginal delivery causes a permanent lowering of resting anal pressures. The possible reasons for this are discussed. Author.

6. AUTHOR	Sultan-A-H, Kamm-M-A, Bartram-C-I, Hudson-C-N.
INSTITUTION	St. Bartholomew's Hospital (Homerton), West Smithfield, London, UK.
TITLE	Anal sphincter trauma during instrumental delivery.
SOURCE	Int-J-Gynaecol-Obstet 1993 Dec, VOL: 43 (3), P: 263-70, ISSN: 0020-7292.
ABSTRACT	OBJECTIVES: To determine the incidence of defecatory symptoms, pudendal nerve damage and mechanical trauma to the anal sphincters during vacuum and forceps delivery. METHODS: Anal endosonography, manometry, pudendal nerve terminal motor latency (PNTML) measurements and perineometry were performed in 43 primiparae who had an instrumental delivery (17 vacuum and 26 forceps) and in 47 who had a normal vaginal delivery (controls). RESULTS: Defecatory symptoms developed in 10 (38%) women following a forceps delivery compared with 2 (4%) in the control group (P = 0.0003), and 2 (12%) following a vacuum extraction (P = NS). Anal sphincter defects occurred in 21 (81%) forceps deliveries compared with 17 (36%) controls (P = 0.0005) and 4 (21%) vacuum extractions (P = NS). Anal pressures were lower in those who developed a sphincter defect (P < 0.00001). PNTML was not significantly altered by the mode of delivery. CONCLUSIONS: Compared with vacuum extraction, forceps delivery is associated with significantly more damage to the anal sphincters and hence an increased incidence of defecatory symptoms. Author.

7. AUTHOR	Combs-C-A, Robertson-P-A, Laros-R-K-Jr.
INSTITUTION	Department of Obstetrics, Gynecology and Reproductive Sciences, University of California San Francisco.
TITLE	Risk factors for third-degree and fourth-degree perineal lacerations in forceps and vacuum deliveries.
SOURCE	Am-J-Obstet-Gynecol 1990 Jul, VOL: 163 (1 Pt 1), P: 100-4, ISSN: 0002-9378.
ABSTRACT	Third- and fourth-degree perineal lacerations occur frequently during operative vaginal deliveries. To identify risk factors for lacerations, 2832 consecutive forceps and vacuum extraction deliveries were analyzed. Third- and fourth-degree lacerations occurred in 30% of deliveries. Multiple logistic regression was used to control for intercorrelation between potential risk factors. Factors associated with increased risk for third- and fourth-degree lacerations were midline episiotomy, nulliparity, second-stage arrest, occipitoposterior position, low or mid station, use of forceps instead of vacuum, use of local anesthesia, and Asian race. When these factors were controlled, there was no effect of birth weight, faculty versus resident operator, gestational age, abnormalities of first-stage labor, or several other factors. Prevention of perineal lacerations requires that the operator identify the patient at risk. Possible options for management of high-risk patients include use of mediolateral episiotomy or no episiotomy, use of vacuum extraction instead of forceps, and use of conduction anesthesia. Author.

8. AUTHOR	Goldaber-K-G, Wendel-P-J, McIntire-D-D, Wendel-G-D-Jr.
INSTITUTION	Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas 75235-9032.
TITLE	Postpartum perineal morbidity after fourth-degree perineal repair.
SOURCE	Am-J-Obstet-Gynecol 1993 Feb, VOL: 168 (2), P: 489-93, ISSN: 0002-9378.
ABSTRACT	OBJECTIVE: We attempted to determine the frequency of postpartum perineal morbidity (dehiscence, infection, and rectovaginal fistula) in women after fourth-degree perineal repair. STUDY DESIGN: The medical records of 390 women at Parkland Memorial Hospital with fourth-degree perineal repair during 1989 and 1990 were retrospectively reviewed in a case-cohort study. Statistical analysis included chi 2 contingency tables, Fisher exact test, Mann-Whitney test, and analysis of variance. RESULTS: Twenty-one of 390 women (5.4%) had postpartum perineal morbidity. Seven (1.8%) had dehiscence alone, 11 (2.8%) had infection and dehiscence, and 3 (0.8%) had infection alone. Overall there were 18 dehiscences (4.6%) and 14 infections (3.6%) in the total group with perineal morbidity. Two high rectovaginal fistulas were concomitantly detected in women with perineal dehiscence. Only shoulder dystocia, metritis, and postpartum fever occurred significantly more frequently in patients with postpartum perineal morbidity than in women without perineal morbidity. Smoking and human papillomavirus infection were not associated with perineal repair morbidity. CONCLUSIONS: Postpartum perineal morbidity after fourth-degree perineal repair is an uncommon event. It is not predicted by readily preventable antepartum or intrapartum factors. Author.