Chronic pancreatitis is a progressive inflammatory condition of the pancreas, which presents with repetitive episodes of pancreatic inflammation leading to extensive scarring, chronic pain, exocrine and endocrine pancreatic insufficiency, reduced quality of life, and a shorter life expectancy [1]. Though the symptoms are often managed with the help of pain medication and a range of medical and surgical interventions, currently, no cure is available [2]. Total pancreatectomy is a last resort treatment for pain relief in patients when the disease involves the entire pancreas with pancreatitis-associated mutations, characteristic pathologic features of progressive fibrosis in pancreas parenchyma, atrophy, and/or ductal occlusion. This procedure consists of isolating the patient’s own islets from the resected pancreas and infusion into the portal vein. The islets eventually become engrafted within the hepatic parenchyma and start secreting insulin in response to the blood glucose without needing immunosuppression [2, 3, 4]. 
We have performed a retrospective review of the TPIAT patients at OHSU to evaluate peri and post-operative outcomes. Eleven patients underwent TPIAT (2019 through 2022, no surgeries were done in 2020) with a median age of 43 years, of which 54.5% were female. Sixty three percent of the patients had a pancreatitis-associated genetic mutation, and 18% had pancreas divisum. The median surgical time was 730 minutes, and the average length of stay in the hospital was 15 days. The median total islet equivalents (IEQ) was 535,160, and the islet equivalents per kg of body weight (IEQ/kg) was 5630. Pain outcome was measured as the requirement of morphine equivalent units per day. At 90 days postoperatively, the narcotic requirement was reduced by 45% (n=11, p<0.05), and at 36 months postoperatively, none of the patients required narcotics (n=3). Median glycemic control measured as hemoglobin A1C was 6.9 at 90 days (n=10) and 7.8 at 12 months (n=6) postoperatively. At 36 months postoperatively, the Hemoglobin A1C was 6.6 (n=3). One patient was completely insulin independent 6 weeks postoperatively. Based on our observations, the following factors negatively affected the total islet yield (IEQ), thus possibly contributing to glycemic control post-transplantation; 1. age of the patient at the time of TPIAT, 2. BMI, 3. pancreatitis-associated genetic mutation, 4. level of acinar cell atrophy, and 5. intrapancreatic fat. SF-12 quality of life scores suggest improved quality of life post-TPIAT in physical and mental domains. 
Our experience demonstrates that TPIAT is an effective surgical intervention for patients experiencing debilitating pain with pancreatitis. Auto-transplantation of the Islets of Langerhans helps minimize post-surgical brittle diabetes; 73% of our patients demonstrate insulin independence or partial graft function. Though it is considered a highly invasive surgical procedure, it can provide significant pain relief, narcotic independence, and restoration of quality of life for chronic pancreatitis patients.

References:
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2.     Bakker OJ, Issa Y, van Santvoort HC, Besselink MG, Schepers NJ, Bruno MJ, Boermeester MA, Gooszen HG. Treatment options for acute pancreatitis. Nat Rev Gastroenterol Hepatol. 2014 Aug;11(8):462-9. doi: 10.1038/nrgastro.2014.39. Epub 2014 Mar 25. PMID: 24662281.
3.     Beilman G. Pancreatitis: Is TPIAT the answer for treatment of chronic pancreatitis? Nat Rev Gastroenterol Hepatol. 2014 Mar;11(3):144-5. doi: 10.1038/nrgastro.2014.11. Epub 2014 Feb 4. PMID: 24492275.
4.     Bellin MD, Abu-El-Haija M, Morgan K, Adams D, Beilman GJ, Chinnakotla S, Conwell DL, Dunn TB, Freeman ML, Gardner T, Kirchner VA, Lara LF, Long-Simpson L, Nathan JD, Naziruddin B, Nyman JA, Pruett TL, Schwarzenberg SJ, Singh VK, Smith K, Steel JL, Wijkstrom M, Witkowski P, Hodges JS; POST study consortium. A multicenter study of total pancreatectomy with islet autotransplantation (TPIAT): POST (Prospective Observational Study of TPIAT). Pancreatology. 2018 Apr;18(3):286-290. doi: 10.1016/j.pan.2018.02.001. Epub 2018 Feb 6. PMID: 29456124; PMCID: PMC5879010.