Pancreatic tissue fluid pressure during drainage operations for chronic pancreatitis

Interventions for Pancreatitis-New Approaches, Knowledge Gaps, and Research Opportunities: Summary of a National Institute of Diabetes and Digestive and Kidney Diseases Workshop

ABSTRACT

There exists no cure for acute, recurrent acute or chronic pancreatitis and treatments to date have been focused on managing symptoms. A recent workshop held by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) focused on interventions that might disrupt or perhaps even reverse the natural course of this heterogenous disease, aiming to identify knowledge gaps and research opportunities that might inform future funding initiatives for NIDDK. The breadth and variety of identified active or planned clinical trials traverses the spectrum of the disease and was conceptually grouped for the workshop into behavioral, nutritional, pharmacologic and biologic, and mechanical interventions. Cognitive and other behavioral therapies are proven interventions for pain and addiction, but barriers exist to their use. Whilst a disease specific instrument quantifying pain is now validated, an equivalent is lacking for nutrition - and both face challenges in ease and frequency of administration. Multiple pharmacologic agents hold promise. Ongoing development of Patient Reported Outcome (PRO) measurements can satisfy Investigative New Drug (IND) regulatory assessments. Despite multiple randomized clinical trials demonstrating benefit, great uncertainty remains regarding patient selection, timing of intervention, and type of mechanical intervention (endoscopic versus surgery). Challenges and opportunities to establish beneficial interventions for patients were identified.

Surgical Management of Chronic Pancreatitis: A Systemic Review

Chronic pancreatitis is a debilitating disease. It is caused by the progressive destruction of normal pancreatic parenchyma, which is replaced by fibrous tissue causing pain in addition to pancreatic insufficiency. There is no single mechanism of pain in chronic pancreatitis. Several medical, endoscopic, and surgical treatment strategies are available to control this disease. Surgical techniques are divided into resection, drainage, and hybrid procedures. The review aimed to compare various surgical procedures used in the management of chronic pancreatitis. The ideal operation is the one that effectively and persistently relieves the pain and has the least morbidity with favorable pancreatic reserve. All the randomized control trials from inception to January 2023, which fulfilled the inclusion criteria, were extensively searched on PubMed and a systemic review was conducted comparing the surgical outcomes of the variety of operations used in chronic pancreatitis. Duodenum-preserving pancreatic head resection is the common procedure done with favorable outcomes.

Endoscopic management of chronic pancreatitis

Chronic pancreatitis (CP) is a common gastrointestinal illness, which affects the quality of life with substantial morbidity and mortality. The management includes medical, endoscopic and surgical approaches with the need for interaction between various specialties, calling for a concerted multidisciplinary approach. However, at the time of this publication, guidelines to establish care of these patients are lacking. This review provides the reader with a comprehensive overview of the studies summarizing the various treatment options available, including medical, surgical and endoscopic options. In addition, technological advances such as endoscopic retrograde cholangiopancreatogrophy, endoscopic shock wave lithotripsy and endoscopic ultrasound can now be offered with reasonable success for pancreatic decompression, stricture dilatation with stent placement, stone fragmentation, pseudocyst drainage, and other endoscopic interventions such as celiac plexus block for pain relief. We emphasize the endoscopic options in this review, and attempt to extract the most up to date information from the current literature. The treatment of CP and its complications are discussed extensively. Complications such as biliary strictures. pancreatic pseudocysts, and chronic pain are common issues that arise as long-term complications of CP. These often require endoscopic or surgical management and possibly a combination of approaches, however choosing amongst the various therapeutic and palliative modalities while weighing the risks and benefits, makes the management of CP challenging. Treatment goals should be not just to control symptoms but also to prevent disease progression. Our aim in this paper is to advocate and emphasize an evidence based approach for the management of CP and associated long term complications.

Unraveling the mystery of pain in chronic pancreatitis

Chronic pancreatitis is typically a painful condition and it can be associated with a severe burden of disease. The pathogenesis of pain in this disorder is poorly understood and its treatment has been largely empirical, often consisting of surgical or other invasive methods, with an outcome that is variable and frequently unsatisfactory. Human and experimental studies have indicated a critical role for neuronal mechanisms that result in peripheral and central sensitization. The pancreatic nociceptor seems to be significantly affected in this condition, with increased excitability associated with downregulation of potassium currents. Some of the specific molecules implicated in this process include the vanilloid receptor, TRPV1, nerve growth factor, the protease activated receptor 2 and a variety of others that are discussed in this Review. Studies have also indicated novel therapeutic targets for this condition.

26. Pain in chronic pancreatitis

Chronic pancreatitis is defined as a progressive inflammatory response of the pancreas that has lead to irreversible morphological changes of the parenchyma (fibrosis, loss of acini and islets of Langerhans, and formation of pancreatic stones) as well as of the pancreatic duct (stenosis and pancreatic stones). Pain is one of the most important symptoms of chronic pancreatitis. The pathogenesis of this pain can only partly be explained and it is therefore often difficult to treat this symptom. The management of pain induced by chronic pancreatitis starts with lifestyle changes and analgesics. For the pharmacological management, the three-step ladder of the World Health Organization extended with the use of co-analgesics is followed. Interventional pain management may consist of radiofrequency treatment of the nervi splanchnici, spinal cord stimulation, endoscopic stenting or stone extraction possibly in combination with lithotripsy, and surgery. To date, there are no randomized controlled trials supporting the efficacy of radiofrequency and spinal cord stimulation. The large published series reports justify a recommendation to consider these treatment options. Radiofrequency treatment, being less invasive than spinal cord stimulation, could be tested prior to considering spinal cord stimulation. There are several other treatment possibilities such as endoscopic or surgical treatment, pancreatic enzyme supplementation and administration of octreotide and antioxidants. All may have a role in the management of pain induced by chronic pancreatitis.

Pain and chronic pancreatitis: is it the plumbing or the wiring?

Our progress in understanding the biology of chronic pancreatitis has been slow, particularly with respect to the pathogenesis of pain, the cardinal symptom. Although traditional theories have focused on anatomic changes, with interstitial and ductal hypertension as the main inciting factors for pain generation, subsequent studies have not confirmed a correlation between ductal pressure and the severity of pain or its relief after ductal decompression. Empirical approaches directed at anatomic causes are at best of marginal value. Although these phenomena are clearly associated with the disease, they are not likely the root cause of the pain. Instead, they probably are inciting factors on a background of neuronal sensitization induced by damage to the perineurium and subsequent exposure of the nerves to mediators and products of inflammation. In this review, we discuss the inherent limitations in our current therapies and try to identify new targets and approaches for the future, such as TRPV1, nerve growth factor-TrkA signaling, and perhaps protease activator receptor-2.

[Pathogenesis and treatment of pain in chronic pancreatitis]

Chronic pancreatitis is an inflammatory, usually painful disease characterized by progressive fibrosis and the loss of exocrine and endocrine functions. Pain influences the quality of life of patients and may lead to inability to work and frequent hospitalisation. The pathogenesis of pain in chronic pancreatitis is still unclear. Several different mechanisms of pain have been proposed, but pain in chronic pancreatitis is most probably multifactorial. Pain management in chronic pancreatitis is difficult. This is due to the multifactorial origin, there are no standardized methods to quantify pain and patients are often addicted to alcohol in chronic pancreatitis. This review summarises the different hypotheses of pain and the possibilities of pain management in chronic pancreatitis.

Intrapancreatic axonal hyperbranching of dorsal root ganglia neurons in chronic pancreatitis model rats and its relation to pancreatic pain

OBJECTIVES

Increase in number of intrapancreatic nerve bundles has been implicated in the generation of persistent pain in chronic pancreatitis. To examine the origin of these nerve fibers and the mechanisms linking neural morphological change to pain generation, we used neuronal tracing techniques in combination with immunohistochemistry in spontaneous chronic pancreatitis in the Wistar Bonn/Kobori (WBN/Kob) rats.

METHODS

For retrograde tracing, horseradish peroxidase was injected into the pancreas, and labeled neurons in the sensory ganglia were counted. For anterograde tracing, biotinylated dextran amine was injected into the dorsal root ganglia (DRGs), and labeled intrapancreatic sensory fibers were histochemically assessed. For assessment of pain generation, we evaluated c-Fos-positive neurons in the spinal dorsal horn and behavioral changes of the animals.

RESULTS

In WBN/Kob rats, the numbers of horseradish peroxidase-labeled neurons were decreased in the DRGs, and the numbers of biotinylated dextran amine-labeled intrapancreatic nerve fibers and terminals were increased. Biotinylated dextran amine-labeled nerve fibers contained growth-associated protein 43. The number of c-Fos-positive neurons in the dorsal horn was also increased and was correlated with intrapancreatic growth-associated protein 43 immunoreactivity. Grooming behavior was reduced in WBN/Kob rats, and this reduction was facilitated by exocrine stimulation.

CONCLUSIONS

Axonal branching in DRG neurons innervating the pancreas increases in WBN/Kob rats, and these morphological changes are likely involved in pain generation in chronic pancreatitis.

Nerve blocks and neuroablative surgery for chronic pancreatitis

Surgical decompressive procedures for "large-duct" chronic pancreatitis have been notably successful in relieving pain. However, management of patients with intractable pain from "small-duct" chronic pancreatitis has been difficult, often resulting in narcotic addiction and/or malnutrition from major pancreatic resection. In view of the disappointing results from extensive pancreatic resections in these cases, denervation of pancreatic sympathetic pain afferents has been suggested as an alternative. Although denervation procedures have been attempted at multiple anatomical levels, results have unfortunately been mixed. The observed variability in results has been attributed to poor patient selection, incomplete understanding of neurophysiology of pancreatic pain, and perhaps inadequate knowledge of pancreatic neuroanatomy. At present, the preferred form of neural ablation is splanchnicectomy. However, a consistent and reliable method for identifying candidates for splanchnicectomy is critical, as it is clinically difficult to distinguish true pancreatic pain from other nociceptive conditions masquerading as pancreatic pain. Differential epidural anesthesia (DEA) is a promising, safe test for initial evaluation and patient selection, although it is not as precise as sometimes claimed. Patients responding to sympathetic block during DEA seem to be the best candidates for operative sympathetic ablation. At the moment, the optimal surgical approach to splanchnic ablation, which offers the least morbid technique, most favorable results, and an attractive risk-benefit ratio, is bilateral thoracoscopic splanchnicectomy. More experience and longer follow-up will be necessary to evaluate this approach.

Endoscopic treatment of the main pancreatic duct: correlations among morphology, manometry, and clinical follow-up

BACKGROUND AND AIM

During the course of chronic pancreatitis, the gradual increase in the main pancreatic duct pressure is the main pathophysiological factor responsible for pain, but up to now, the intra ductal pressure has never been measured during and after endoscopic stenting and correlated with clinical results. Pressure measurements of this kind could thus provide objective information about the useful duration of stenting period.

METHODS

Main pancreatic duct pressure was measured by performing endoscopic manometry on 13 chronic pancreatitis symptomatic patients (10 men, 3 women, mean age: 45.1+/-7.9 yr); clinical follow-up was carried out for a period of 29.0+/-16.1 mo. Before treatment, the main anatomical alteration present was a localized stenosis of the main pancreatic duct, i.e., one with a diameter of less than 2 mm (chronic pancreatitis alone), 10 cases; chronic pancreatitis associated with pancreas divisum, 3 cases). Stenosis was treated by endoscopic stenting: 7 F stent (7 cases) and 12 F stent (6 cases). The pressure was measured simultaneously in the duodenum (zero level) and within the main pancreatic duct, using an electronic device, The pancreatico-duodenal gradient was taken to be the difference between the pressure in the main pancreatic duct and the duodenum.

RESULTS

The endoscopic stenting induced a nonsignificant decrease in the intraductal pressure (p = 0.16). Among the 9 patients with a normal pressure at the end of the stenting and a successful anatomical outcome, 6 were painless during the follow-up period whereas 3 presented with recurrent pancreatic-type pain. The remaining 4 patients were symptom-free during the entire follow-up period, although the main pancreatic duct pressure was high at the end of the stenting and the stenosis was not completely cured.

CONCLUSION

The intraductal pressure at the end of the stenting period was perfectly correlated with the anatomical result, whether or not it was successful, but was not an accurate predictor of a favorable clinical outcome in patients with a poor anatomical result.

Effect of pancreaticojejunostomy on fibrosis, pancreatic blood flow, and interstitial pH in chronic pancreatitis: a feline model

OBJECTIVE

To study the relation between fibrosis, pancreatic blood flow (PMBF), interstitial pH (pHi), and the effects of pancreaticojejunostomy (PJ) in chronic pancreatitis.

BACKGROUND

Chronic pancreatitis is associated with low PMBF and pHi, suggesting the existence of underlying ischemia.

METHODS

In cats, the main pancreatic duct was partially obstructed and the animals were studied 2, 4, 6, and 8 weeks later. PJ was performed after 2 and 4 weeks of ductal obstruction and studied 4 weeks later. PMBF and pH were measured before and after stimulation with secretin and cholecystokinin. pHi was measured with microelectrodes, PMBF by hydrogen gas clearance. Histologic analysis of the pancreas with Sirius red (collagen stain) and fast green FCF (noncollagen protein) stains allowed semiquantitative analysis of the ratio between collagen and total protein (C/TP).

RESULTS

With the evolution of chronic pancreatitis, there is a progressive increase in the collagen content and C/TP ratio, a reduction in basal PMBF and pHi, and loss of the normal response to stimulation. Early PJ restores collagen content, C/TP ratio, and basal and stimulated PMBF and pHi to normal. PJ performed in established CP returns the C/TP ratio to normal, improves basal PMBF, and restores the normal hyperemic response to secretion. Basal pHi is improved and the "acid tide" associated with secretin returns, but there is still no response to cholecystokinin.

CONCLUSIONS

Pancreaticojejunostomy restores the elevated collagen and C/TP ratio to normal and reverses the ischemia present in CP. The authors speculate that restoration of PMBF and its normal response to stimulation allows "regeneration" and restoration of secretory function.

Pain relief and functional recovery after endoscopic interventions for chronic pancreatitis

BACKGROUND

Pain and functional deterioration in chronic pancreatitis is multifactorial. Early surgery in non-alcoholic patients with mild to moderate chronic pancreatitis can relieve pain and prevent progression of pancreatic insufficiency for some time, but the good results are only short term. Endoscopic intervention can relieve pain and recover pancreatic function without surgery.

METHODS AND RESULTS

To achieve the burned out state of chronic pancreatitis, occlusion of the pancreatic duct was first attempted by our team with Ethibloc at ERCP. Temporary obstruction of the pancreatic duct did not result in a long-lasting symptom and relapse-free situation because of early recovery of pancreatic function. On the contrary, endoscopic simple and double papillotomy, pancreatic drainage with citrate lavage, biliary endoprosthesis with multiple stents and endoscopic decompression of pseudocysts with or without jejunal feeding resulted in pain-free patients for a considerable time and in several cases significant functional recovery occurred. In cases where pain remained, percutaneous celiac plexus block with long-lasting steroids can be applied and only if all of these treatments fail should surgery be recommended.

CONCLUSION

Endoscopic intervention can successfully substitute for surgery for chronic pancreatitis in individual cases.

Does allopurinol reduce pain of chronic pancreatitis?

CONCLUSION

A dosage of 300 mg/d of allopurinol was not effective in reducing pain or improving activities of daily living in chronic pancreatitis.

BACKGROUND

Allopurinol prevents the generation of oxygen-derived free radicals by inhibiting xanthine oxidase. The purpose of this study was to determine whether allopurinol is effective in reducing pain of chronic pancreatitis.

METHODS

Thirteen patients with chronic pancreatitis who were experiencing abdominal pain requiring medication at least three times each week entered a randomized, double-blind, two-period crossover clinical trial. Patients evaluated their pain daily using a categorical pain intensity scale, numeric pain intensity scale, and a visual analog scale, and weekly completed a McGill Pain Questionnaire and activities of daily living (ADL) questionnaire.

RESULTS

The mean baseline score of pain was approx 50% of most severe pain in all scoring systems. There was no significant decrease in pain associated with allopurinol compared to the placebo (p = 0.24-0.75). In addition, there was no benefit in terms of ADL score associated with allopurinol compared with placebo (p = 0.32). Mean uric acid level was decreased by 1.15 mg/dL while patients were taking allopurinol, compared to when they were taking placebo (p = 0.007).

Chronic pancreatitis

Chronic pancreatitis is a serious disease with many yet unsolved problems, e.g. pathogenesis, cause of pain and treatment. Danish gastroenterologists have for many years participated actively in the investigation of the disease and have produced many internationally recognized results, especially regarding secretion physiology and pathophysiology, epidemiology, cause of pain and characterization of the secondary diabetes mellitus. In the past 25 years more than 60 Danish papers about chronic pancreatitis have been published in international, reviewed journals. Furthermore six theses on subjects related to chronic pancreatitis have been produced. In this article the Danish contribution to the literature on chronic pancreatitis during the past 25 years is reviewed.

Sphincter of Oddi motility

BACKGROUND

Technical improvement in endoscopic and manometric technique has allowed direct manometry of the human sphincter of Oddi (SO). The aim of the present review is to describe the present status of physiologic and clinical knowledge of the SO, with emphasis on contributions from Danish Gastroenterology.

RESULTS

The SO is a zone with an elevated basal pressure with superimposed phasic contractions. It acts mainly as a resistor in the regulation of bile flow. Neurohormonal regulation influences the motility pattern. The contractions are under the control of slow waves. Clinical subgroups show abnormalcy in SO manometric pattern especially in patients with biliary or pancreatic pain without demonstrable organic substrate. Evidence suggests that endoscopic sphincterotomy may be of benefit in these patients.

Is increased pancreatic pressure related to pain in chronic pancreatitis?

In this study, we investigated the relationship between pain and pancreatic pressure in patients with chronic pancreatitis (CP). We studied 12 patients with CP undergoing surgery and five controls with cancer of the pancreatic tail. CP was staged on the basis of morphological (ERP) and functional (serum-pancreolauryl test) criteria. Patients kept daily records of the intensity of pain on a linear analog scale. Intraoperatively, pressure within the pancreas was assessed by the introduction of a fine needle into the pancreatic parenchyma connected to a pressure transducer. In controls, pressure was determined in macroscopically normal tissue in the head of the pancreas. Pancreatic pressure was significantly higher in CP than in controls (29.9 +/- 3.1 vs 7.2 +/- 1.1 mmHg, p < 0.001). No relationship was found between the pain score and the pancreatic pressure. Pressure was positively correlated with ductal changes (r = 0.831; p < 0.001), but not with exocrine function of the pancreas. Postoperatively, pancreatic pressure fell by 15.3% in four patients with CP in whom pressure assessment was repeated after surgical decompression. We conclude that pancreatic parenchyma pressure is not closely related to pain in CP.