3T external phased-array magnetic resonance imaging in detection of obstetric anal sphincter lesions: a pilot study.

BACKGROUND: Three-dimensional endoanal ultrasound (3D EAUS) has been the gold standard for detecting anal sphincter lesions in patients with a history of obstetric anal sphincter injury (OASI). Advances in imaging technologies have facilitated the detection of these lesions with external phased-array magnetic resonance imaging (MRI), which could offer an alternative imaging modality for the diagnosis of residual OASI (ROASI) in centers where 3D EAUS imaging is not available. PURPOSE: To compare two diagnostic modalities: the 3D EAUS and 3T external phased-array MRI in the detection of residual anal sphincter lesions. MATERIAL AND METHODS: A total of 24 women with a history of OASI were imaged with both 3D EAUS and 3T external phased-array MRI after primary repair of the injury. Intraclass correlation (ICC) and interrater reliability (IRR) values were calculated for the grade and circumference of the sphincter lesion. Sphincter lesions were graded according to the Sultan classification. RESULTS: There was an almost perfect agreement between 3D EAUS and 3T external phased-array MRI in determining the extent of the sphincter lesions according to the Sultan classification (κ = 0.881; P < 0.001) and the circumference of the external anal sphincter defects, measured in degrees (κ = 0.896; P < 0.001). CONCLUSION: The results of this study indicate that 3T external phased-array MRI and 3D EAUS yield comparable results in the diagnosis of ROASI. These findings suggest that 3T external phased-array MRI could serve as an alternative diagnostic modality to 3D EAUS in the diagnosis of ROASI.

Comparison of 3D endoanal ultrasound and external phased array magnetic resonance imaging in the diagnosis of obstetric anal sphincter injuries.

OBJECTIVES: The gold standard of postpartum anal sphincter imaging has been the 3D endoanal ultrasound (EAUS). Development of magnetic resonance imaging (MRI) has allowed anal sphincter evaluation without the use of endoanal coils. The aim of this study is to compare these two modalities in diagnosing residual sphincter lesions post obstetric anal sphincter injury (OASI). METHODS: Forty women were followed up after primary repair of OASI with both 3D EAUS and external phased array MRI. Details of the anal sphincter injury and sphincter musculature were gathered and analysed. RESULTS: There was a moderate interrater reliability (κ = 0.510) between the two imaging modalities in detecting sphincter lesions, with more lesions detected by MRI. There was a moderate intraclass correlation (ICC) between the circumference of the tear (κ = 0.506) and a fair ICC between the external anal sphincter thickness measurements at locations 3 and 9 on the proctologic clock face (κ = 0.320) and (κ = 0.336). CONCLUSIONS: The results of our study indicate that the use of external phased array MRI is feasible for detecting obstetric anal sphincter lesions postpartum. This allows for imaging of the sphincter defects in centres where EAUS imaging is not available. KEY POINTS: • A two centre prospective study that showed external phased array MRI to be a valid imaging modality for diagnosing obstetric anal sphincter injuries.

Impact of sphincter lesions and delayed sphincter repair on sacral neuromodulation treatment outcomes for faecal incontinence: results from a Finnish national cohort study.

PURPOSE: The aim of this multicentre study was to analyse the effects of patent sphincter lesions and previous sphincter repair on the results of sacral neuromodulation (SNM) treatment on patients with faecal incontinence (FI). METHODS: Patients examined by endoanal ultrasound (EAUS) with FI as the indication for SNM treatment were included in the study. Data was collected from all the centres providing SNM treatment in Finland and analysed for differences in treatment outcomes. RESULTS: A total of 237 patients treated for incontinence with SNM had been examined by EAUS. Of these patients, 33 had a history of previous delayed sphincter repair. A patent sphincter lesion was detected by EAUS in 128 patients. The EAUS finding did not influence the SNM test phase outcome (p = 0.129) or the final treatment outcome (p = 0.233). Patient's history of prior sphincter repair did not have a significant effect on the SNM test (p = 0.425) or final treatment outcome (p = 0.442). CONCLUSIONS: Results of our study indicate that a sphincter lesion or previous sphincter repair has no significant effect on the outcome of SNM treatment. Our data suggests that delayed sphincter repair prior to SNM treatment initiation for FI is not necessary.

Factors predicting a failed primary repair of obstetric anal sphincter injury.

INTRODUCTION: The success of the primary repair of obstetric anal sphincter injury (OASI) is paramount in maintaining adequate fecal continence after childbirth. The factors determining the success or failure of primary repair are unclear. The aim of this study is to investigate modifiable factors determining the success or failure of the primary sphincter repair after OASI. MATERIAL AND METHODS: Sixty women with OASI were investigated by endoanal ultrasound or magnetic resonance imaging, and with the Wexner incontinence questionnaire. Based on the findings, the women were divided in two groups; successful primary repair group (n = 41) and failed primary repair group (n = 19). RESULTS: The primary repair failed in 31.7% of the tears. These included more tears repaired by less experienced personnel (p < 0.001) and more repairs performed during on-call hours (p = 0.039) than in the successful primary repair group. Significantly more pain medication was used in the failed group (p = 0.003), and the use of antibiotics and laxatives after the repair was more common in the successful group (p < 0.001). Sphincter injuries were repaired using the overlapping suture technique in 95.1% of the repairs in the successful group compared with 47.4% in the failed group (p = 0.03). The mean (SD) Wexner score was significantly higher in the failed group [5.92 (4.1) vs. 1.88 (4.2), p < 0.001], in agreement with the findings on endoanal ultrasound. CONCLUSIONS: Postpartum perineal tears should be evaluated by personnel familiar with the diagnosis and repair of OASI. Delaying the primary repair until next morning is recommended if experienced personnel are unavailable during on-call hours.