Sphincter Of Oddi dysfunction: Still a viable entity?

“The greatest trick the Devil ever pulled was convincing the world he didn’t exist.”
—Roger “Verbal” Kint, The Usual Suspects (1995  film)

My fourth-year interventional endoscopy fellowship consisted of three-month rotations alternating between two different academic referral institutions. The endoscopic retrograde cholangiopancreatography (ERCP) practice at one institution utilized sphincter manometry to triage the need for sphincterotomy in patients with suspected sphincter of Oddi dysfunction (SOD). The ERCP practice at the other institution favored empiric sphincterotomy in lieu of manometry in patients felt to be at high pre-test probability for disease, irrespective of SOD classification.

Based on this experience (and on witnessing the performance of empiric biliary sphincterotomy despite a normal manometric result), my personal doubts about the value of manometry have centered on this premise: If we are evaluating an entity which is episodic and dynamic, and if we obtain a normal manometric result during an asymptomatic period, then what have we really learned? My current institution had abandoned the use of sphincter manometry by the time I joined faculty a decade ago, and our interventional group has not felt compelled to resurrect use of manometry in the interval since.

Our evidence-based understanding of SOD has evolved during the past decade. The Evaluating Predictors and Interventions in Sphincter of Oddi Dysfunction (EPISOD) study found a high placebo response rate among patients randomized to sham, and compared to the sham group, no reduction in disability due to pain among patients randomized to a sphincterotomy algorithm.1 In the realm of pancreatic SOD and recurrent acute pancreatitis, a large single-center experience reported prevention of recurrent acute pancreatitis in 50 percent of patients who underwent biliary sphincterotomy, but no added benefit of dual biliary and pancreatic sphincterotomies.2 The newest Rome criteria for functional gallbladder and sphincter of Oddi disorders has even raised a motion to strike “sphincter of Oddi dysfunction” from the lexicon, instead reclassifying SOD type I as sphincter stenosis, SOD type II as suspected functional biliary sphincter disorder and SOD type III as functional pain, respectively.3 Among these, suspected functional biliary sphincter disorder may represent the lone remaining realm of sphincter manometry.

I am convinced that few of us as gastroenterologists can truly ascertain the full scope and long-term outcomes of individual patients who present with functional biliary pain.

However, the entity of SOD remains very much in our conscious minds as gastroenterologists and clinical practice as pancreatobiliary endoscopists. The main reason for this is that we continue to see patients with persistent, legitimate and debilitating post-cholecystectomy pain who are desperate for symptom relief. Some patients with functional pain arrive with high hopes for ERCP, having been told by perhaps well-meaning but nonetheless misinformed referring physicians that a sphincterotomy offers their long-sought cure. Walking a patient back from this precipice can be a delicate and time-consuming endeavour, and may result in low post-encounter satisfaction scores generated by both patient and provider. Other patients report having undergone prior ERCP for SOD with durable symptom relief thereafter, only to now experience the recurrence of identical symptoms, and may insist on undergoing repeat ERCP. For such a patient, an ERCPist faces a conundrum: Was the initial symptom response merely due to placebo effect, or might in fact such a patient now suffer from a new iatrogenic entity, sphincter stenosis, or stricture as a consequence of prior sphincterotomy?

I am convinced that few of us as gastroenterologists can truly ascertain the full scope and long-term outcomes of individual patients who present with functional biliary pain. Factors including geographic mobility of both patients and physicians, as well as mutable access to hospital networks dictated by third-party payor status, may hamper maintenance of longitudinal patient-physician partnerships. Some patients seen in consultation for functional biliary pain are seeking input as a second, third or fourth opinion — perhaps because of unwillingness of a prior physician to offer ERCP, or perhaps instead a consequence of an adverse event suffered during ERCP at the hands of a prior physician.

Two premises should underscore our continued approach to patients with suspected SOD.  First, we must recognize and duly inform our patients with suspected SOD that they are at incontrovertibly increased risk of ERCP-induced pancreatitis should ERCP be pursued. Second, we must acknowledge that our understanding of the neurobiology of pain is too fundamentally limited to allow faith with a high degree of confidence that indiscriminately incising a small (but important!) sphincter will irrevocably alter the symptom profile of a complex foregut unit.

For non-believers, the entity of SOD will remain a difficult dragon to slay. For believers, it would be prudent to heed the advice of the Rome IV statement: “This is a clinical minefield, which patients and physicians should enter only with extreme caution.”3

Disclosures: Dr. Yachimski has no conflicts to disclose.

References

1. Cotton P.B., Durkalski V., Romagnuolo J., et al. Effect of endoscopic sphincterotomy for suspected sphincter of Oddi dysfunction on pain-related disability following cholecystectomy: the EPISOD randomized clinical trial. JAMA. 2014;311:2101-2109.
2. Coté G.A., Imperiale T.F., Schmidt S.E., et al. Similar efficacies of biliary, with or without pancreatic, sphincterotomy in treatment of idiopathic recurrent acute pancreatitis. Gastroenterology. 2012;143:1502-1509.
3. Cotton P.B., Elta G.H., Carter C.R., et al. Gallbladder and Sphincter of Oddi disorders. Gastroenterology. 2016;doi:10.1053/j.gastro.2016.02.033.

Join the discussion

Your email address will not be published. Required fields are marked *