In the Driving Seat with High-Resolution Ano-Rectal Manometry

Introduction: High-resolution ano-rectal manometry (HRAM), part of the investigative process to diagnose disorders of recto-anal co-ordination, is currently performed in the left-lateral position (LLP). This may seem unnatural for patients and recent data suggest that the seated, squatted position (SP) may improve rectal drive and recto-anal pressure gradients, raising the question as to whether defaecatory dyssenergia (DD) is over-diagnosed when the test is carried out in the LLP. Aim/method: A single centre study was carried out in patients with faecal incontinence and/or constipation to evaluate the effect of SP versus LLP on HRAM analysis and resultant manometric diagnosis of DD. Positioning was consecutive and the order was randomised for each patient. The HRAM protocol was carried out in accordance with the manufacturer’s guidelines (Manoscan). Data analysis and interpretation were blinded with a consensus reached for each test position. Data (mean ± SEM) were analysed using an unpaired t-test and Chi-square test. Results: In total, 40 patients completed the study, including 33 females with a median age of 56 (IQR 48–63). The mean rectal drive was significantly higher in the SP vs. LLP (82.6 ± 5.3 mmHg vs. 44.1 ± 3.9 mmHg, respectively, p < 0.0001). No difference in the anal sphincter relaxation pressure (66.7 ± 5.7 mmHg vs. 70.9 ± 5.5 mmHg, p = 0.9535) was detected. The manometric diagnoses of abnormal ano-rectal co-ordination were significantly higher in the LLP, when p = 0.013. Patients reported a significant preference for the seated position, when p = 0.0001. Conclusion: These data show that HRAM in the seated position improves rectal drive, which reduces manometric diagnoses of abnormal ano-rectal coordination. These findings may have important implications for practice and may inform future guidelines.