Sods sphincter of Oddi Dysfunction

Sods sphincter of Oddi Dysfunction

1. Sphincter of O ddi Dysfunction (SOD) Anup Shrestha Dept of Surgery CMC

2. Content Introduction Anatomy and Physiology Pathophysiology Clinical Presentation Classification Investigation 1. non-invasive 2. invasive Treatment 1. Medical 2. Endoscopic 3. Surgical

3. Introduction a benign, noncalculous obstruction to the flow of biliary or pancreatic secretions through the pancreaticobiliary junction SOD is an uncommon disorder, affecting most often middle-aged women. Approximately 10% of patients develop pain post cholecystectomy, and 10% of those will have SOD 10–20% of patients with idiopathic recurrent pancreatitis may suffer from SOD Two types --SO dyskinesia refers to a primary motor abnormality of the SO that may result in a hypertonic sphincter . -- SO stenosis refers to a structural alteration of the sphincter, probably from an inflammatory process, with subsequent fibrosis

4. Anatomy It consists of three segments of smooth muscle: the CBD segment, which is approximately 10 mm in length; the pancreatic segment , which is roughly 6 mm in length; and the segment of the confluence of both the bile duct and pancreatic duct, which is intraduodenal for close to 6 mm in length There are three discrete areas of muscle thickness, or mini sphincters: the sphincter papillae, the sphincter pancreaticus , and the sphincter choledochus

5. Physiology -Sphincter regulation is under both neural and hormonal control - CCK and secretin appear to be most important in causing sphincter relaxation The sphincter of Oddi is an independent motor unit that has a high-pressure zone in the distal choledochus approximately 5 mm Hg greater than the pressure in the distal common bile duct. The basal pressure of the sphincter is 5–15 mm Hg greater than the common bile duct pressure, and 15–30 mm Hg greater than the pressure in the duodenum. Superimposed on this resting pressure are rhythmic phasic wave contractions at an amplitude of 50–150 mm Hg and a frequency of 2–5 contractions/minute The sphincter of Oddi has three main functions: regulation of flow of bile and pancreatic juice into the duodenum prevention of reflux from the duodenum into the bile duct and pancreatic duct filling of the gallbladder.

6. Pathophysiology Interruption of the cholecystosphincteric reflex with cholecystectomy may affect sphincter behavior. Alternatively, inflammation during cholecystitis may be an inciting painful stimulus which leads to nociceptive sensitization and ultimately allodynia during physiologic bile duct or duodenal distention hormonal factors seem to play a significant role in the motility pattern. CCK is a potent inhibitor of the ampullary sphincter. Secretin acts to inhibit the pancreatic portion of the sphincter of Oddi

7. Clinical Presentation Classic pancreatobiliary -type, episodic upper abdominal pain, typically postprandial in nature and associated with nausea. they may present with recurrent idiopathic pancreatitis.

8. Modified Milwaukee Classification System

9. Diagnosis a consistent history of pancreatobiliary -type pain The most standard test used for evaluation of SOD is endoscopic retrograde cholangiopancreatography ( ERCP) with endoscopic sphincter of Oddi manometry ( ESOM) Sustained ductal pressures greater than 35 to 40 mm Hg above baseline are indicative of SOD . pancreatitis reported in 4 % to 31% of patients

10. Non- Invasive methods Morphine- prostigmin provocative test ( Nardi test) an intramuscular or subcutaneous injection of morphine 10 mg & neostigmine 1 mg This test relies on the property of morphine sulfate to cause sphincter of Oddi contraction and neostigmine to stimulate pancreaticobiliary secretions through cholinergic pathways. Endpoints include a reproduction of the patient’s typical pain as well as a 4-fold elevation of the serum ALT, AST , alkaline phosphotase , amylase, or lipase at 30 minutes following the injection ( Sgouros SN, Pereira SP. Systematic review: sphincter of Oddi dysfunction-noninvasive diagnostic methods and long-term outcome after endoscopic sphincterotomy . Aliment Pharmacol Ther , 2006 )

11. Fatty meal-stimulated assessment of pancreaticobiliary system This non-invasive method uses a standardized fatty meal (usually 250 mL of whole milk ) to stimulate gallbladder contraction, increase hepaticoduodenal bile flow, and cause sphincter of Oddi relaxation . In cases of SOD where there may be a paradoxical contraction of the sphincter of Oddi in response to stimulation, an increase of the pancreaticobiliary ductal diameter may be seen when compared to baseline. This assessment is usually performed using transabdominal ultrasonography or MRCP Low sensitivity -21%

12. Hepatobiliary scintigraphy Performed in fasting state with administration of radionuclide tracer If SOD, obstructed biliary flow is expected

13. Hopkins Scintigraphic Scoring System

14. Sphincter of Oddi Manometry (SOM) considered to be the “gold standard” in the diagnosis SOM is highly recommended in patients with type II SOD, and is mandatory in patients with type III SOD, with sphincterotomy response rates predicted by the presence of abnormal sphincter of Oddi readings . Approximately 50 %–60% of type II SOD patients will have an abnormal manometry , with response rates of up to 75% to sphincterotomy in those with abnormal pressure findings . Type III SOD patients are far more complex, with only 25% of these patients having an abnormal reading, though 50% of type III SOD patients respond to sphincterotomy Sphincter of Oddi dysfunction is diagnosed when the basal sphincter pressure is greater than 40 mm Hg.

15. Response to Therapy

16. Treatment - Medical Therapy Nitrates and calcium channel blockers have been the most extensively studied A placebo-controlled, cross-over study found that nifedipine reduced pain scores, emergency room visits, and use of oral analgesia in 75% of patients with manometrically documented SOD ( Khuroo MS et al. Efficacy of nifedipine therapy in patients with sphincter of Oddi dysfunction: a prospective, double-blind , randomized, placebo-controlled, cross over trial. Br J Clin Pharmacol . 1992 ) Other agents used includes lowdose tricyclic antidepressants, selective serotonin reuptake inhibitors (SSRIs), gabapentin Drawbacks: -Systemic side effects of these agents limit their long-term use - improvement is often temporary, short lived, or incomplete. - patients with the mechanical form of SOD (sphincter of Oddi stenosis)usually fail to respond to any medical therapy

17. Endoscopic Therapy Biliary Stenting. Biliary stenting can be used as a short-term alternative to sphincterotomy as well as a therapeutic trial to determine response to a sphincterotomy . However , the risk of complications like post-stenting cholangitis has limited its widespread use, and it is not a recommended procedure.

18. Botulinum toxin Botulinum toxin, a potent inhibitor of acetylcholine release 100 units of botulinum toxin is injected into the major papilla as a single injection . In a study A 5% rate of pancreatitis was observed with about half the patients deriving symptom relief at 6 weeks . alternative to endoscopic sphincterotomy in selected patients with a short duration of response Wehrmann T, Seifert H, Seipp M, et al. Endoscopic injection of botulinum toxin for biliary sphincter of Oddi dysfunction. Endoscopy , 1998;30:702-707

19. Endoscopic Sphincterotomy Endscopic sphincterotomy is the current standard therapy for treating patients with SOD . The biliary and/or pancreatic segment of the sphincter of Oddi can be severed by electrocautery during ERCP . The location of the sphincterotomy should be between the 11 o'clock and 1 o’clock positions. Deep cannulation is then facilitated. Once deep cannulation is achieved, the endoscopist can withdraw the sphincterotome tailored to the desired incision length The incision should be directed along the longitudinal axis of the intramural segment of the common bile duct  An endoscopic sphincterotomy should cause ablation of the hypertensive or dysfunctional sphincter The main aims of treatment are the relief of pancreaticobiliary pain and the avoidance of recurrent pancreatitis .

20. The performance of a pancreatic sphincterotomy in addition to a biliary sphincterotomy ( ie , dual sphincterotomy ) may improve long-term outcomes . Dual sphincterotomy is indicated in all type III SOD patients in whom pancreatic manometry is abnormal or in those who present with recurrent symptoms following a recent prior biliary sphincterotomy Complication: 1) pancreatitis seen in up to 20% - can be reduced by the placement of a pancreatic duct stent 2) Duodenal perforation can also occur due to the small size of the ducts involved

21. Surgical Therapy Surgical treatment consists of transduodenal sphincteroplasty with or without transampullary septectomy Those patients who have failed prior endoscopic intervention (generally because of restenosis) and those patients who have undergone previous gastric surgery, particularly gastric bypass with Roux-en-Y reconstruction

22. Reference Shackelford’s SURGERY of the ALIMENTARY TRACT(8 th Edition) BLUMGART’S Surgery of the Liver, Biliary Tract, and Pancreas( 6 th Edition) DISEASES OF THE BILLIARY TRACT, SERIES # 2 Rad M. Agrawal https:// www.hopkinsmedicine.org Köksal AS, Eminler AT, Parlak E. Biliary endoscopic sphincterotomy : Techniques and complications. World J Clin Cases 2018 Staritz M. (2008) Sphincter of Oddi Physiology and Pathophysiology. In: Beger H.G., Matsuno S., Cameron J.L., Rau B.M., Sunamura M., Schulick R.D. ( eds ) Diseases of the Pancreas. Springer, Berlin