Patterns of abnormal pudendal nerve function that are associated with postpartum fecal incontinence

Objective

The purpose of this study was to assess patterns of abnormal pudendal nerve function in women who complain of postpartum fecal incontinence.

Study design

During a 12-month period, a cohort of 83 women underwent neurophysiologic assessment as part of an evaluation of fecal incontinence after vaginal delivery. Pudendal nerve assessment consisted of the measurement of the clitoral-anal reflex and quantitative electromyography of the external anal sphincter. Endoanal ultrasound examination and anal manometry were also performed in each patient.

Results

Thirty of 83 women (38%) with fecal incontinence were found to have abnormal neurophysiologic condition, among whom four identifiable patterns of abnormality emerged. Five women (17%) had evidence of pudendal nerve demylenation with a prolonged sensory threshold of the clitoral-anal reflex (>5.2 mA), although electromyography studies were normal. Eight women (27%) had abnormal electromyography results that were consistent with axonal neuropathy with or without reinervation, in whom the clitoral-anal reflex was normal. Thirteen women (43%) demonstrated a mixed demyelinating and axonal pudendal neuropathy, with evidence of reinervation. Four women (13%) had abnormal patterns of neurophysiologic condition that was not attributable directly to past obstetric trauma but to coincident medical problems.

Conclusion

Four abnormal patterns of pudendal nerve function may be identified, three of which (demyelinating, axonal, and mixed demyelinating/axonal) can be attributed to specific past obstetric events, although a fourth radicular pattern is due to coincident medical or orthopedic problems. Assessment of pudendal nerve function is important in women with postpartum fecal incontinence because particular patterns of abnormality correlate with different symptoms and can influence treatment options.     

Neonatal brachial plexus palsy: an unpredictable injury

OBJECTIVE: Brachial plexus paralysis is a serious form of neonatal morbidity. We determined its incidence and persistence of disability and evaluated whether its occurrence could be predicted by maternal characteristics or partographic analysis in a large cohort of recent cases. STUDY DESIGN: During the years 1994 through 1998, all infants with neonatal evidence of obstetric brachial plexus injury were identified and followed 14;>or=1 year. Obstetric details in these maternal-infant pairs were compared with 108 control pairs, matched for maternal and gestational age, parity, and birth weight. Partographs of cases and control subjects were reviewed, in a blinded manner, by 3 obstetricians who were asked to identify likely cases of nerve injury. A risk score comprising eight recognized associated clinical features was assigned. RESULTS: Fifty-four of 35,796 infants (1.5/1000) had evidence of brachial plexus injury; in 10 cases (19%), neurologic deficit persisted to 1 year. Although the risk factor profile was relatively higher in cases compared with control subjects, the highest score was 5 of 8 in six cases (2 cases, 4 control subjects). Obstetricians' partographic assessment identified "likely brachial plexus injury" in 13 of 54 cases (24%) and 16 of 108 control subjects (15%), and in only 3 cases (6%) did the assessors concur (positive predictive value, 7%-17%; negative predictive value, 5%-12%; sensitivity, 24%-50%; specificity, 66%-68%). Risk scores were similar among persistently and transiently injured cases. CONCLUSION: Our results indicate that brachial plexus injury is not predictable before delivery, either by risk factor scoring or by partographic analysis.     

Genotypic and phenotypic correlations of DFNB1-related hearing impairment in the Midwestern United States

OBJECTIVE: To determine the genotypic and phenotypic correlations of hearing impairment (HI) in a midwestern US population related to autosomal recessive nonsyndromic hearing loss locus 1 (DFNB1). DESIGN: A retrospective review. SETTING: Tertiary care children's hospital. PATIENTS: A total of 160 consecutive children diagnosed with idiopathic sensorineural hearing loss. MAIN OUTCOME MEASURES: GJB2 genotype and audiometric phenotype. RESULTS: The prevalence of subjects with HI having biallelic GJB2-related mutations was 15.3% (24/157). Of these 24 patients, 9 (38%) were homozygous 35delG, 6 (25%) had other biallelic nonsense mutations, and 9 (38%) had a missense mutation of at least 1 allele. The allelic prevalence of 35delG was 8.6% (27/314) in the study population and 48% (23/48) in the DFNB1 group. The M34T allele mutation was next most prevalent at 2.2% (7/314) in the study population and 10% (5/48) in the DFNB1 group. Severe to profound HI occurred in 59% of DFNB1 subjects. Genotypes with biallelic nonsense mutations had a high risk of severe to profound HI (88%). DFNB1-related HI was usually bilateral, symmetric, nonprogressive, and had flat audiograms. However, asymmetric HI (22%), sloping audiograms (26%), and even borderline-normal hearing in 1 ear was observed, and these were associated with the presence of at least 1 missense mutation. Two novel mutations, K15T and L90V, were identified. A subject presenting to our clinic with severe to profound HI had a 40% risk of biallelic GJB2 mutation. CONCLUSIONS: Our population represents a consecutively enrolled clinic population with sensorineural hearing loss. In our DFNB1-related HI cohort, the 35delG mutation and severe to profound HI rates were lower than previously reported. Our missense mutation and M34T allelic prevalence rates were higher than expected and were associated with a less severe hearing loss. The presence of biallelic nonsense mutations was associated with severe to profound hearing loss in nearly 90% of cases. Mild asymmetric HI and sloping audiograms were more often associated with missense mutations.     

Type IIA procollagen in development of the human intervertebral disc: regulated expression of the NH(2)-propeptide by enzymic processing reveals a unique developmental pathway.

Type II collagen can be synthesized in two forms generated by alternative splicing of the precursor mRNA. Type IIA procollagen, which contains a cysteine-rich domain in the NH(2)-propeptide (exon 2), is produced by precartilage and noncartilage epithelial and mesenchymal cells, and type IIB procollagen, without the cysteine-rich domain, is characteristic of chondrocytes. Mice lacking type II collagen fail to develop intervertebral discs. We have previously shown that the human intervertebral disc and notochord synthesize primarily the type IIA form of procollagen. Therefore, we investigated the distribution of type IIA procollagen during early disc development in humans. By processes of radioactive in situ hybridization and fluorescence immunohistochemistry, we localized mRNA and protein of type IIA procollagen, type I collagen, and type III collagen in fetal intervertebral disc specimens ranging from day 42 (embryonic stage 17) to day 101 (week 14.5) of gestation. Antibodies to the three distinct domains of type IIA procollagen: the NH(2)-propeptide, the fibrillar domain, and the COOH-propeptide were used. The earliest stage of developing intervertebral disc (42 days, stage 17) was characterized by diffuse synthesis of types I and III collagens in the dense zone (intervertebral area) and synthesis of type IIA procollagen by the chondrocyte progenitor cells surrounding the disc. The notochord cells synthesized and deposited into the notochordal sheath all three fibrillar collagens. By 54 days (stage 22), the developing disc was clearly divided into three regions: 1.) the outer annulus, characterized by synthesis and deposition of types I and III collagens; 2.) the inner annulus, characterized by synthesis and deposition of type IIA collagen containing the NH(2)-propeptide but devoid of the COOH-propeptide (pN-procollagen); and 3.) the notochord, the cells of which synthesized and deposited of all three fibrillar collagens. In later stages of fetal development (72-101 days), a change in type IIA procollagen processing was observed in the cells of the inner annulus: even though these cells continued to synthesize type IIA procollagen, they deposited into the extracellular matrix (ECM) only the processed fibrillar domain, with the NH(2)-propeptide removed. This finding indicates that there is a developmentally regulated change in the processing of type IIA procollagen NH(2)-propeptide in the cells of the inner annulus. This mechanism is in contrast to previously shown developmental regulation of the cysteine-rich domain of the NH(2)-propeptide by alternative splicing of the precursor mRNA. Although the cells of the inner annulus have been identified as chondrocytes, based on their shape and synthesis of characteristic ECM components, they appear to represent a distinct developmental pathway characterized by their synthesis and differential processing of type IIA procollagen. This developmental pattern may prove important for disc regeneration.     

Measurement of a novel optic disc topographic parameter, ”spikiness”, in glaucoma

Background: Structural changes in the lamina cribrosa have been implicated in the pathogenesis of glaucomatous optic atrophy, but not observed. This paper presents a novel parameter of topographic variability within the optic disc, termed ”spikiness”, which may reflect glaucoma-related changes in the lamina. Methods: Four age-matched groups of normal patients (n=12, mean age 64.8 years) and patients with ocular hypertension (n=14, mean age 63.1), primary open-angle glaucoma (n=11, mean age 70) and low-tension glaucoma (n=15, mean age 66.3) were recruited. Images of normal and glaucomatous eyes from the Heidelberg Retina Tomograph were imported into ERDAS image processing software where the spikiness data (30 consecutive mean surface height values across the base of the optic cup in both the vertical and horizontal meridians) were extracted in a format that facilitated further statistical analysis. Results: Significant differences in topographic variability (spikiness) existed in the vertical (F=3.64, P=0.01) but not the horizontal meridian (F=1.25, P=0.3) through the optic disc. Spikiness was inversely related to Humphrey mean deviation (P<0.05), and cup-disc ratio (P<0.004) and was directly related to nerve fibre layer thickness (P<0.005). Of particular interest was the finding that the spikiness measure was the only optic disc parameter to significantly discriminate low tension glaucoma from primary open angle glaucoma. Conclusion: A new measure of surface variability (topography) at the floor of the optic cup has been described. The new index of spikiness may represent a measurement of lamina cribrosa fragility which has been implicated, but not previously estimated, in glaucomatous eyes. Received: 6 January 2000 Revised: 27 March 2000 Accepted: 30 March 2000