Evaluation and Management of Patients with January 8, 2001 Constipation Objectives •What is anorectal manometry? Anorectal Manometry: •Equipment An Overview • Indications • Pitfalls Joseph M. Croffie, MD, MPH •Examples of tracings James Whitcomb Riley Hospital for Children Indiana University School of Medicine Indianapolis, Indiana Anorectal Manometry • Allows study of the function of structures which are responsible for continence and defecation: ‐ Rectum ‐ Internal anal sphincter ‐ External anal sphincter Indications for Anorectal Manometry Equipment •To diagnose a non‐relaxing internal anal sphincter in patients with persistent constipation •Computer and software •To evaluate postoperative patients with Hirschsprung’s that have obstructive symptoms, and to evaluate the effect of •Manometric catheters Botulinum toxin injection of the anal sphincter in such ‐ Schuster stationary triple‐balloon patients •To evaluate patients with fecal incontinence ‐ Water‐perfused •To evaluate post‐operative patients with persistent ‐ Solid state: Conventional or high resolution elimination difficulties after imperforate anus repair ‐ Air‐coupled •To decide if a patient is a candidate for biofeedback therapy •Perfusion pump for water‐ perfused and to facilitate biofeedback training Neurogastroenterol Mot 2002;14:411-420. John M. Wo, M.D. 1 Evaluation and Management of Patients with January 8, 2001 Constipation Anorectal Manometry Catheters Manometric Studies •Perfused vs solid state Schuster stationary catheter Water-perfusion Solid-state Air‐Coupled Disposable Air‐Coupled Anorectal Manometry is Anorectal Manometry Catheters Comparable to Solid‐State Catheters •No need for water‐perfusion •Much less expensive than solid‐state catheters • Available with: ** * Circumferential or ** Directional sensors * Fang et al. Dig Dis Sci 2004;49:1657 High‐Resolution Solid‐State ARM: Resting Pressures Anorectal Manometry Catheter 8‐12 sensors with hundreds of measurement points: •7‐10, closely spaced sensors every 6mm for sphincter measurements •1‐2 unidirectional sensors for rectum/ balloon •3D Catheter with several axial and Circumferential sensors and up to 256 points of measurement John M. Wo, M.D. 2 Slide 12 J1 Joe, 10/20/2012 J2 Joe, 10/20/2012 Evaluation and Management of Patients with January 8, 2001 Constipation ARM: Squeeze Pressures Rectoanal Inhibitory Reflex 50-cc rectal balloon inflation Patient Preparation Measurements •Resting anal pressure: Mostly contributed by internal •No preparation for newborns or breast‐fed infants anal sphincter • Clearance of fecal impaction needed in older children • Squeeze pressure: Mostly contributed by external anal with impaction sphincter •Sedation or anesthesia may be needed in uncooperative • Effect of rapid rectal distension on resting pressure: child in which case a full study is not done (Rectoanal inhibitory reflex is absent in Hirschsprung’s disease and anal achalasia) • Threshold for rectal sensation: The smallest volume of rectal balloon distension detected by patient Measurements Anorectal Manometry Measurement Disease States • Threshold for initial urge to defecate: The smallest volume Diabetic/autonomic neuro- of rectal balloon distention that produces an initial urge to Resting • 70-85% internal anal sphincter pathy, Spinal cord lesion, defecate pressure • Parasympathetic motor (S2-S4) anorectal malformation •Maximum tolerable volume of rectal balloon distention (critical volume): The volume of rectal balloon distention Squeeze • 70-85% external anal sphincter Spinal cord lesion, anorectal that produces discomfort or a strong and sustained urge to pressure • Pudendal motor (S2-S4) malformation defecate Rectal • Central and spinal sensory Spinal cord lesion, multiple • Determination of defecation dynamics: Examination of sensation sclerosis, diabetic/autonomic abdominal and external anal sphincter response to patient threshold • Parasympathetic sensory (S2-S4) neuropathy attempting to defecate. In dyssynergia, both abdominal Anorectal • Sphincter relaxation reflex with Hirschsprung’s, anal and external anal sphincter pressures are usually elevated inhibitory balloon distension achalasia reflex • Myenteric plexus John M. Wo, M.D. 3 Evaluation and Management of Patients with January 8, 2001 Constipation Anorectal Manometry Normal Anorectal Manometry Imperf Multiple Hirsch- Cauda Normal Myelo Anus Sclerosis sprung’s Equina Internal 50-80 Normal Normal Normal sphincter mmHg or External 80-260 Normal or Normal sphincter mmHg Rectal Absent sensation 10-30 cc Normal Normal threshold or Present but Present but Anorectal abnormal abnormal Complete inhibitory Absent dose response Normal Absent dose relaxation reflex and anal response and spasms anal spasms Normal Simulated Defecation Hirschsprung’s disease Normal Simulated Defecation Dyssynergic Defecation Push Rectum < 40 Anus Rao et al. Am J Gastroenterol. 1999;94:773-783. John M. Wo, M.D. 4 Evaluation and Management of Patients with January 8, 2001 Constipation Dyssynergic Defecation Neurologic Causes of Obstructive Defecation Push •Impaired rectal sensation: – Myelomeningocele –Multiple sclerosis –Spinal cord injury – Cauda equina syndrome •Impaired sphincter relaxation: – Hirschsprung's disease –Anal achalasia Non‐neurologic Causes of Obstructive Defecation Biofeedback for Anismus in Children Paradoxical sphincter contraction during defecation (dyssynergic defecation / anismus) • Randomized trials have shown there is no long‐term • Behavioral: benefit in children –Pain during defecation •No correlation between improvement in defecation –Surgery, fissures dynamics and outcome • Following chronic fecal withholding •May be beneficial in carefully selected patients • Following repair of Hirschsprung’s disease • Following sexual abuse Idiopathic Pitfalls in Anorectal Manometry Pitfalls in Anorectal manometry •False positive results (absence of RAIR) can be obtained in •Avoid anal stretching just before manometry; may patients with megarectum due to inadequate volume to result in false or equivocal sphincter pressures and stretch the rectal wall response to rectal distension •Improper positioning of the catheter such that the rectal • Restlessness during the examination may affect balloon is too close to the upper border of the sphincter sphincter manometric results can result in false‐positive RAIR when the balloon • Squeezing of the external anal sphincter following stretches the sphincter with distension rectal distention may result in inability to see RAIR • Demonstration of the RAIR can be difficult if resting tone is •Note exact positioning of pressure recording sensors in low the anal canal to avoid false‐positive or false‐negative • Premature infants and infants <1 month old are more sphincter responses. Check position regularly likely to have equivocal results John M. Wo, M.D. 5 Evaluation and Management of Patients with January 8, 2001 Constipation John M. Wo, M.D. 6.