Altered central pain processing after pancreatic surgery for chronic pancreatitis

Updates in the Management of Chronic Pancreatitis: Navigating Through Recent Advances

This article provides an up-to-date review of the management of chronic pancreatitis, highlighting advancements in medical therapy, nutritional support, endoscopic and surgical approaches, and emerging treatments. Nutritional management accentuates addressing malabsorption and nutrient deficiencies. Advances in endoscopy and parenchyma-sparing surgical techniques have opened new avenues for improved patient outcomes, with total pancreatectomy and islet autotransplantation offering the only definitive solution for selected patients. Additionally, emerging therapies, including anti-inflammatory and immune-modulating agents, show promise for future treatment options. Emphasizing a multidisciplinary approach, this review aims to equip health care professionals with a comprehensive overview of current management strategies and future directions.

Long-Term Outcomes of Early Surgery vs Endoscopy First in Chronic Pancreatitis: Follow-Up Analysis of the ESCAPE Randomized Clinical Trial

Importance

Patients with painful chronic pancreatitis and a dilated pancreatic duct can be treated by early surgery or an endoscopy-first approach.

Objective

To compare long-term clinical outcomes of early surgery vs an endoscopy-first approach using follow-up data from the ESCAPE randomized clinical trial.

Design, Setting, and Participants

Between April 2011 and September 2018, 88 patients with painful chronic pancreatitis were randomly assigned to early surgery or an endoscopy-first approach in 30 hospitals in the Netherlands collaborating in the Dutch Pancreatitis Study Group as part of the ESCAPE randomized clinical trial. For the present cohort study, long-term clinical data were collected after the initial 18-month follow-up. Follow-up was completed in June 2022, and data analysis was performed in June 2023.

Exposure

Patients with chronic pancreatitis were randomly assigned to early surgery or an endoscopy-first approach.

Main Outcomes and Measures

The primary end point was pain, assessed by the Izbicki pain score; secondary end points included patient-reported complete pain relief and satisfaction. Predefined subgroups included patients who progressed from endoscopy to surgery and those with ductal clearance obtained by endoscopy. Analysis was performed according to the intention-to-treat principle.

Results

In this cohort study, 86 of 88 overall patients could be evaluated, with a mean (SD) follow-up period of 98 (16) months. Of 88 initial patients, 21 patients (24%) were female, and mean (SD) patient age was 61 (10) years. At the end of long-term follow-up, the mean (SD) Izbicki pain score was significant lower (33 [31] vs 51 [31]) in the early surgery group, as was the rate of patient-reported complete pain relief (14 of 31 patients [45%] vs 6 of 30 patients [20%]), compared to the endoscopy-first group. After the initial 18-month follow-up, 11 of 43 patients in the early surgery group (26%) underwent reinterventions vs 19 of 43 patients in the endoscopy-first group (44%). At the end of follow-up, more patients in the early surgery group were "very satisfied" with their treatment (22 of 31 patients [71%] vs 10 of 30 patients [33%]). Patients who progressed from endoscopy to surgery (22 of 43 patients [51%]) had significantly worse mean (SD) Izbicki pain scores (33 [31] vs 52 [24]) compared to the early surgery group and had a lower rate of complete pain relief (55% for early surgery vs 12% for endoscopy first). In the endoscopy-first group, patients with endoscopic ductal clearance had similar mean (SD) Izbicki pain scores as the remaining patients (49 [34] vs 53 [28]).

Conclusions and Relevance

In this cohort study evaluating long-term outcomes of the ESCAPE randomized clinical trial, after approximately 8 years of follow-up, early surgery was superior to an endoscopy-first approach in patients with painful chronic pancreatitis and a dilated main pancreatic duct in pain scores and patient satisfaction. Notably, patients who progressed from endoscopy to surgery had worse outcomes compared to patients undergoing early surgery, and obtaining endoscopic ductal clearance did not improve outcomes.

Hypoalgesia and Conditioned Pain Modulation in Blood Flow Restriction Resistance Exercise

We compared the magnitude of exercise-induced hypoalgesia and conditioned pain modulation between blood-flow restriction (BFR) resistance exercise (RE) and moderate-intensity RE. Twenty-five asymptomatic participants performed unilateral leg press in two visits. For moderate-intensity RE, subjects exercised at 50% 1RM without BFR, whereas BFR RE exercised at 30% 1RM with a cuff inflated to 60% limb occlusion pressure. Exercise-induced hypoalgesia was quantified by pressure pain threshold changes before and after RE. Conditioned pain modulation was tested using cold water as the conditioning stimulus and mechanical pressure as the test stimulus and quantified as pressure pain threshold change. Difference in conditioned pain modulation pre- to post-RE was then calculated. The differences of RE on pain modulations were compared using paired t-tests. Pearson's r was used to examine the correlation between exercise-induced hypoalgesia and changes in conditioned pain modulation. We found greater hypoalgesia with BFR RE compared to moderate-intensity RE (p=0.008). Significant moderate correlations were found between exercise-induced hypoalgesia and changes in conditioned pain modulation (BFR: r=0.63, moderate-intensity: r=0.72). BFR RE has favorable effects on pain modulation in healthy adults and the magnitude of exercise-induced hypoalgesia is positively correlated with conditioned pain modulation activation.

Conditioned pain modulation (CPM) paradigm type affects its sensitivity as a biomarker of fibromyalgia

Fibromyalgia (FM) is a widespread chronic pain syndrome, possibly associated with the presence of central dysfunction in descending pain inhibition pathways. Conditioned Pain Modulation (CPM) has been proposed as a biomarker of FM. Nonetheless, the wide variety of methods used to measure CPM has hampered robust conclusions being reached. To clarify the validity of CPM as a biomarker of FM, we tested two CPM paradigms (parallel and sequential) in a sample of 23 female patients and 23 healthy women by applying test (mechanical) stimuli and conditioning (pressure cuff) stimuli. We evaluated whether CPM indices could correctly classify patients and controls, and we also determined the correlations between the indices and clinical variables such as symptomatology, disease impact, depression, quality of life, pain intensity, pain interference, fatigue and numbness. In addition, we compared the clinical status of CPM responders (efficient pain inhibitory mechanism) and non-responders. We observed that only parallel CPM testing correctly classified about 70% of patients with FM. In addition, more than 80% of healthy participants were found to be responders, while the rate was about 50% in the FM patients. The sequential CPM test was not as sensitive, with a decrease of up to 40% in the response rate for both groups. On the other hand, we did not observe any correlation between CPM measures and clinical symptoms. In summary, our findings demonstrate the influence of the CPM paradigm used and confirm that CPM may be a useful marker to complement FM diagnosis. However, the findings also cast doubts on the sensitivity of CPM as a marker of pain severity in FM.

Pharmacological management of patients undergoing total pancreatectomy with auto-islet transplantation

Chronic pancreatitis results in permanent parenchymal destruction of the pancreas gland leading to anatomical and physiological consequences for patients. Surgical management varies, and some patients require total pancreatectomy with autologous islet cell transplantation (TPIAT). Patients undergoing TPIAT require complex and diligent management after surgery. This encompasses the management of glucose control (endocrine function of the pancreas) and supplementing loss of exocrine function of the pancreas with digestive enzymes. Other areas of management include optimizing pain relief while reducing narcotic usage, providing antimicrobial prophylaxis, and reducing loss of islet cells by improving its integrity through anticoagulation and use of anti-inflammatory agents. Each aspect of care is unique to this population. However, comprehensive reviews on its pharmacological management are scarce. This review will discuss the available literature to date surrounding all aspects of pharmacological management of patients undergoing TPIAT.

Pain Sensitivity and Psychiatric Comorbidities in Chronic Pancreatitis Patients With and Without Pain: Past Experience Matters

Background and Aims

Pain is the primary symptom of chronic pancreatitis (CP) and has been associated with abnormal pain processing and psychologic distress. Little is known about these phenomena in patients with painless disease. The aim of this study was to characterize patterns of pain processing and psychologic distress in patients with primary painless vs painful CP.

Methods

This was a cross-sectional multicenter study of 235 patients with definitive CP. Patients were categorized based on current and past pain history; current pain (79%), no current (but prior) pain (11%), and painless CP (10%). Demographic information and clinical data including symptoms of anxiety and depression using the Hospital Anxiety and Depression Scale were collected. All patients underwent quantitative sensory testing to assess patterns of pain processing.

Results

A total of 235 patients (57% males, mean age 53.9 ± 14.0 years, 41% alcohol etiology) were included. Compared to patients with painless CP, enhanced pain sensitivity was observed in both patients with current pain (odds ratio [OR] 3.29; 95% confidence interval [CI] [1.11-9.77], P = .032) and no current pain (OR 4.07; 95% CI [1.10-15.03], P = .035). Patients with current pain also had increased depression prevalence compared to patients with painless CP (OR 6.15; 95% CI [1.28-29.41], P = .023), while no difference was seen for patients with no current pain (OR 1.24; 95% CI [0.19-8.26], P = .824).

Conclusion

Total absence of pain in CP is associated with normal pain processing and low prevalence of psychologic distress, whereas patients with prior pain experience appear to have persistent and enhanced pain sensitivity even in the absence of clinical pain and psychologic distress.

Endoscopic Management of Complications in Chronic Pancreatitis

PURPOSE OF REVIEW

Management of complications in patients with chronic pancreatitis is often suboptimal. This review discusses detailed endoscopic approaches for managing complications in CP.

LITERATURE FINDINGS

CP is characterized by progressive and irreversible destruction of pancreatic parenchyma and ductal system resulting in fibrosis, scarring, and loss of glandular function. Abdominal pain remains is the most common symptom of the disease and the main aim of medical, endoscopic, and surgical therapy is to help relieve symptoms, prevent disease progression, and manage complications related to CP. In fact, advances in our understanding of CP have improved medical care and quality of life in these patients. With significant sequela, morbidity and a progressive nature, a thorough understanding of the pathophysiology, natural course, diagnostic approaches, and optimal management strategies for this disease is warranted. The existing modalities and new innovations in this field are safe, effective, and likely to have a positive impact on management of complication in CP whenever used in the right context.

Rationale for and Development of the Pancreatic Quantitative Sensory Testing Consortium to Study Pain in Chronic Pancreatitis

OBJECTIVES

Abdominal pain is the primary symptom of chronic pancreatitis (CP), but pain is difficult to assess, and objective methods for pain assessment are lacking. The characterization of the sensory component of pain as a surrogate for nociception can be achieved by sensory testing using standardized stimuli. Herein, we describe the rationale for and development of an international consortium to better understand and characterize CP pain.

METHODS

A collaboration was initially formed between the University of Aalborg, Johns Hopkins University, and the University of Pittsburgh. This group refined the protocol for pancreatic quantitative sensory testing (P-QST) and then expanded the collaboration with plans for incorporating P-QST into prospective studies.

RESULTS

The collaboration has successfully developed a P-QST nomogram. Chronic pancreatitis patients identified with P-QST as having widespread hyperalgesia had higher pain intensity scores, higher prevalence of constant pain, and decreased quality of life. Psychiatric comorbidities were independent of pain phenotypes. Multiple studies are underway to validate these findings and evaluate their utility in clinical trials.

CONCLUSIONS

Development of the P-QST Consortium will facilitate collaborative efforts to use P-QST as a means for evaluation and characterization of pain in CP patients, and optimize methods to guide individualized pain management approaches.

Assessment of pain associated with chronic pancreatitis: An international consensus guideline

Pain is the most common symptom in chronic pancreatitis (CP) with a major impact on quality of life. Few validated questionnaires to assess pain in CP exist, and the lack of consensus negatively impacts clinical management, research and meta-analysis. This guideline aims to review generic pain questionnaires for their usability in CP, to outline how pain assessment can be modified by confounding factors and pain types, to assess the value of additional measures such as quality of life, mental health and quantitative sensory testing, and finally to review pain assessment questionnaires used specifically in CP. A systematic review was done to answer 27 questions that followed the PICO (Population; Intervention; Comparator; Outcome) template. Quality of evidence of the statements was judged by Grades of Recommendation, Assessment, Development and Evaluation (GRADE) criteria. The manuscript was sent for review to 36 experts from various disciplines and continents in a multi-stage Delphi process, and finally reviewed by patient representatives. Main findings were that generic pain instruments are valid in most settings, but aspects of pain are specific for CP (including in children), and instruments have to account for the wide phenotypic variability and development of sensitization of the central nervous system. Side effects to treatment and placebo effects shall also be considered. Some multidimensional questionnaires are validated for CP and are recommended together with assessment of quality of life and psychiatric co-morbidities. This guideline will result in more homogeneous and comprehensive pain assessment to potentially improve management of painful CP.

Painful chronic pancreatitis - new approaches for evaluation and management

PURPOSE OF REVIEW

Management of abdominal pain in patients with chronic pancreatitis is often suboptimal. We review recent data on the epidemiology and new approaches for managing pain in chronic pancreatitis.

RECENT FINDINGS

Chronic pancreatitis duration does not appear to affect the pain experience. Pain pattern in chronic pancreatitis patients frequently changes and is not related to traditional patient and disease-related factors. Psychologic comorbidities, i.e. anxiety and depression, are frequent in patients with chronic pancreatitis, and are associated with more severe pain and pain interference. Adjunctive treatments, such as cognitive behavioral therapy, may positively influence pain management in chronic pancreatitis. Total pancreatectomy with islet autotransplantation (TPIAT) is an increasingly adopted treatment option in painful chronic pancreatitis. Ongoing multicenter studies will help define optimal candidates, predictors of successful pain remission and diabetes outcomes after TPIAT. Pancreatic quantitative sensory testing, a promising technique to interrogate nociception and sensory response, holds promise to identify patients with central sensitization. Initial studies show feasibility to stratify patients into defined pain profiles, and future studies will explore if these can help in prognostication of pain therapy.

SUMMARY

Several lines of investigations currently under evaluation are likely to have a positive impact on the management of pain in chronic pancreatitis.

Chemical pancreatectomy: an unconventional approach to preventing autodigestion in pancreatitis

Due to progressive inflammation, chronic pancreatitis destroys both the exocrine and endocrine pancreas and sensitizes pancreatic nerves, leading to unremitting pain. Unfortunately, there are no treatments for pancreatic inflammation and approaches to ameliorate pain are suboptimal. Pancreatic inflammation is particularly problematic because damage to acinar cells causes local release of digestive enzymes, which initiate pancreatic autodigestion. The combination of autodigestion and inflammation is unique to pancreatitis and undoubtedly contributes to the difficulty in devising effective treatments. In this issue of the JCI, Saleh et al. describe a nonsurgical technique to ablate pancreatic acinar cells, thus eliminating the source of digestive enzymes and preventing autodigestion. In mice and a nonhuman primate model, this approach effectively reduced inflammation and pain while preserving islet cell function. These findings support the concept that ongoing acinar cell damage is at the root of chronic pancreatitis and provide a possible strategy for clinical treatment.

Swedish national guidelines for chronic pancreatitis

Chronic pancreatitis (CP) should be suspected in the case of recurrent upper abdominal pain of unknown origin and/or clinical signs of exocrine pancreatic insufficiency (EPI). Alcohol is the most common etiological factor associated with CP, others being smoking, male gender, and hereditary forms. CP is often associated with recurrent episodes of acute exacerbations.As of today, there is no accepted clinical definition of CP. However, irreversible morphological changes within the pancreas often occur, including dilatation of the main and branch pancreatic ducts, calcifications in ducts and parenchyma, parenchymal atrophy, and development of pseudocysts, though less so in the early phase of CP.

Patient phenotyping in clinical trials of chronic pain treatments: IMMPACT recommendations

There is tremendous interpatient variability in the response to analgesic therapy (even for efficacious treatments), which can be the source of great frustration in clinical practice. This has led to calls for “precision medicine” or personalized pain therapeutics (ie, empirically based algorithms that determine the optimal treatments, or treatment combinations, for individual patients) that would presumably improve both the clinical care of patients with pain and the success rates for putative analgesic drugs in phase 2 and 3 clinical trials. However, before implementing this approach, the characteristics of individual patients or subgroups of patients that increase or decrease the response to a specific treatment need to be identified. The challenge is to identify the measurable phenotypic characteristics of patients that are most predictive of individual variation in analgesic treatment outcomes, and the measurement tools that are best suited to evaluate these characteristics. In this article, we present evidence on the most promising of these phenotypic characteristics for use in future research, including psychosocial factors, symptom characteristics, sleep patterns, responses to noxious stimulation, endogenous pain-modulatory processes, and response to pharmacologic challenge. We provide evidence-based recommendations for core phenotyping domains and recommend measures of each domain.

Conditioned pain modulation-A comprehensive review

Conditioned pain modulation (CPM) is a centrally processed measure of the net effect of the descending pain pathway. This comprises both the facilitatory as well as the inhibitory effect. In the past, CPM or similar effects have been previously described using different terminologies such as diffuse noxious inhibitory control (DNIC), heterotopic noxious conditioning stimulation (HNCS) or endogenous analgesia (EA). A variety of patient-related factors such as age, gender, hormones, race, genetic and psychological factors have been thought to influence the CPM paradigms. CPM paradigms have also been associated with a wide range of methodological variables including the mode of application of the 'test' as well as the 'conditioning' stimuli. Despite all these variabilities, CPM seems to reliably lend itself to the pain modulation profile concept and could in future become one of the phenotypic biomarkers for pain and also a guide for mechanism-based treatment in chronic pain. Future research should focus on establishing consistent methodologies for measuring CPM and thereby enhancing the robustness of this emerging biomarker for pain.

Effects of chronic pain history on perceptual and cognitive inhibition

Measures of sensory and cognitive inhibition were obtained from university students with and without a history of chronic pain. The form of sensory inhibition measured was diffuse noxious inhibitory controls (DNIC), the capacity of a painful stimulus to reduce the subjective intensity of a second stimulus delivered to a remote body site. To measure cognitive inhibition, the Stroop effect was used. Participants with a history of chronic pain showed less DNIC (i.e., less sensory inhibition) than the healthy controls, but had a smaller Stroop effect (indicating greater cognitive inhibition). The fact that chronic pain history is associated with opposite changes in these two measures casts doubt on the view that the two inhibitory processes are related. Scores on each experimental measure were equivalent in pain-history subjects with ongoing chronic pain and those whose chronic pain had resolved. This equivalence suggests that chronic pain in childhood or adolescence may have lingering effects on sensory and cognitive inhibition.

A clinically feasible method for the assessment and characterization of pain in patients with chronic pancreatitis

BACKGROUND AND AIMS

Pain is the primary symptom of chronic pancreatitis (CP), but methods for sensory testing and pain characterization have not previously been validated for clinical use. We present a clinically feasible method for the assessment and characterization of pain mechanisms in patients with CP based on quantitative sensory testing (QST).

METHODS

This was a cross-sectional, multicenter study of 122 control subjects without pancreatic disease and another 60 patients with painful CP. All subjects underwent standardized QST assessments including a cold pressor test, a conditioned pain modulation paradigm, repetitive pin-prick stimuli (temporal summation) and pressure stimulation of the upper abdominal (pancreatic) and control dermatomes. The effects of age and gender on QST assessment parameters were investigated and normative reference values based on quartile regression were derived and implemented in algorithms to categorize patients according to their patterns of central pain processing (normal vs. segmental sensitization vs. widespread sensitization).

RESULTS

Absolute pressure thresholds were subject to clinically relevant gender effects (all p < 0.001), while the remainder of QST parameters were unaffected by age and gender. The algorithm with the best discriminatory capacity showed good separation between patients and controls (p < 0.001); 50% of patients had normal central pain processing, 23% had evidence of segmental sensitization and 27% had evidence of widespread sensitization.

CONCLUSION

We show normative reference values for a clinically feasible method for assessment and characterization of pain mechanisms in patients with CP. Application of this method streamlines the evaluation of pancreatic pain and may be used to inform treatment. CLINICALTRIALS.

GOV ID

NCT03434392.

Sensitized brain response to acute pain in patients using prescription opiates for chronic pain: A pilot study

BACKGROUND

Chronic opiate use leads to a sensitized behavioral response to acute pain, which in turn, leads to escalating doses of opiates. This study was designed to test the hypothesis that chronic opiate usage is also associated with a sensitized neurobiological response to acute pain in individuals that have used prescription opiates for 6 or more months.

METHODS

Fourteen patients with non-alcoholic chronic pancreatitis that have been taking prescription opiates for 6 or more months and 14 gender matched, non-opiate using controls were enrolled. Functional neuroimaging data was acquired while participants received blocks of thermal stimulation to their wrist (individually-tailored to their pain threshold).

RESULTS

Self-reported pain was significantly greater in opiate using patients (3.4 ± 3.4) than controls (0.2 ± 0.8: Brief Pain Inventory p < 0.005), however no significant difference between groups was observed in the individually-tailored pain thresholds. Opiate using patients evidenced a significantly greater response to pain than controls in two established nodes of the "Pain Matrix": somatosensory cortex (p_FWE≤0.001) and anterior cingulate cortex (p ≤ 0.01). This response was positively correlated with prescribed morphine equivalent dosages (average: 133.5 ± 94.8 mg/day).

CONCLUSION

The findings suggest that in chronic pancreatitis patients, a dose of opiates that normalizes their behavioral response to acute pain is associated with an amplified neural response to acute pain. Further longitudinal studies are needed to determine if this neural sensitization hastens a behavioral tolerance to opiates or the development of an opioid use disorder.

Surgery in Chronic Pancreatitis: Indication, Timing and Procedures

Chronic pancreatitis is a chronic inflammation of the pancreas with pain as its severest symptom and often an impaired quality of life. Surgical intervention plays an important role in the management of pain but is generally kept as a last resort when conservative measures and endoscopy have failed. However, in the last few years multiple studies suggested the superiority of (early) surgical treatment in chronic pancreatitis for multiple end points, including pain relief. In this paper we highlight the most recent high-quality evidence on surgical therapy in chronic pancreatitis and the rationale for early (surgical) intervention.

Designing and conducting proof-of-concept chronic pain analgesic clinical trials

Introduction:

The evolution of pain treatment is dependent on successful development and testing of interventions. Proof-of-concept (POC) studies bridge the gap between identification of a novel target and evaluation of the candidate intervention's efficacy within a pain model or the intended clinical pain population.

Methods:

This narrative review describes and evaluates clinical trial phases, specific POC pain trials, and approaches to patient profiling.

Results:

We describe common POC trial designs and their value and challenges, a mechanism-based approach, and statistical issues for consideration.

Conclusion:

Proof-of-concept trials provide initial evidence for target use in a specific population, the most appropriate dosing strategy, and duration of treatment. A significant goal in designing an informative and efficient POC study is to ensure that the study is safe and sufficiently sensitive to detect a preliminary efficacy signal (ie, a potentially valuable therapy). Proof-of-concept studies help avoid resources wasted on targets/molecules that are not likely to succeed. As such, the design of a successful POC trial requires careful consideration of the research objective, patient population, the particular intervention, and outcome(s) of interest. These trials provide the basis for future, larger-scale studies confirming efficacy, tolerability, side effects, and other associated risks.

Bilateral distribution of anterior cutaneous nerve entrapment syndrome (ACNES): are clinical features and outcomes comparable to unilateral ACNES?

BACKGROUND AND OBJECTIVES

Mirror-image pain may occur in the presence of a one-sided peripheral nerve lesion leading to a similar distribution of pain on the contralateral side of the body ("mirrored"). Anterior cutaneous nerve entrapment syndrome (ACNES) is a neuropathic pain syndrome due to entrapment of terminal branches of intercostal nerves T7-12 in the abdominal wall and sometimes presents bilaterally. This study aims to address specifics of bilateral ACNES and to determine potential differences in clinical presentation and treatment outcomes when compared with the unilateral form of ACNES.

METHODS

Electronic patient files and questionnaires of a case series of patients who were evaluated for chronic abdominal wall pain in a single center were analyzed using standard statistical methods.

RESULTS

Between June 1, 2011 and September 1, 2016, 1116 patients were diagnosed with ACNES, of which a total of 146 (13%) with bilateral ACNES were identified (female, n = 114, 78 %; median (range) age 36 (1181) years). Average NRS (Numeric Rating Scale; 0-10) scores were similar (median (range) NRS scores 6 (0-10) although peak NRS scores were significantly higher in the bilateral group (9 (5-10) vs 8 (2-10); p=0.02). After a median of 26 months (1-68), the proportion of patients with bilateral ACNES reporting treatment success was 61%.

CONCLUSIONS

One in eight patients with ACNES has bilateral abdominal wall pain. Characteristics are similar to unilateral ACNES cases. Further studies aimed at underlying mechanisms in mirror image pain pathogenesis could provide a more targeted approach in the management of this neuropathic pain.

Endoscopic treatment of pain in chronic pancreatitis

PURPOSE OF REVIEW

Pain is the most common symptom of chronic pancreatitis, having a profound effect on patients and a broad socioeconomic impact. Endoscopy is guideline recommended as first-line management for chronic pancreatitis pain in certain clinical scenarios. Herein, we provide an evidence-based review of the endoscopic treatment of pain due to chronic pancreatitis while highlighting some important confounders in the measurement of this outcome in clinical practice and research.

RECENT FINDINGS

Multiple recent studies have reported on the efficacy of current endoscopic therapies for chronic pancreatitis pain. Despite the high technical success rates of these procedures, pain outcomes remain disappointing. Complex mechanisms beyond ductal hypertension, such as central sensitization, visceral hypersensitivity and inflammatory neuritis account for some of the discordance observed between the rates of technical and clinical success. In addition, the sham effect is increasingly recognized as a confounder when interpreting the procedural benefit. Nevertheless, there are multiple promising innovations in the field of pancreatic endoscopy that are aimed to improve technical and clinical outcomes, but rigorous investigation is necessary to establish their role in clinical practice.

SUMMARY

Endoscopic therapy for chronic pancreatitis pain appears to be safe and effective in certain contexts and recent innovations in the field will hopefully further improve outcomes. In addition to evaluating the technical success of endotherapy in chronic pancreatitis, methodologically rigorous research focusing on patient-centered outcomes and accounting for the sham effect is necessary to advance this field.

Total pancreatectomy and islet autotransplantion for chronic and recurrent acute pancreatitis

PURPOSE OF REVIEW

We reviewed the current state of total pancreatectomy with islet autotransplantation (TPIAT) for chronic pancreatitis and recurrent acute pancreatitis (RAP).

RECENT FINDINGS

An increasing number of centers in the United States and internationally are performing TPIAT. In selected cases, TPIAT may be performed partially or entirely laparoscopically. Islet isolation is usually performed at the same center as the total pancreatectomy surgery, but new data suggest that diabetes outcomes may be nearly as good when a remote center is used for islet isolation. Ongoing clinical research is focused on patient and disease factors that predict success or failure to respond to TPIAT. Causes of persistent abdominal pain after TPIAT may include gastrointestinal dysmotility and central sensitization to pain. Several clinical trials are underway with anti-inflammatory or other islet protective strategies to better protect islets at the time of infusion and thereby improve the diabetes results of the procedure.

SUMMARY

In summary, there is an increasing body of literature emerging from multiple centers highlighting the benefits and persistent challenges of TPIAT for chronic pancreatitis and RAP. Ongoing study will be critical to optimizing the success of this procedure.

Beyond Abdominal Pain: Pain Beliefs, Pain Affect, and Distress as Determinants of Quality of Life in Patients With Chronic Pancreatitis

GOALS

To assess the relationship between pain, psychological processes, and quality of life (QOL) in chronic pancreatitis (CP).

BACKGROUND

CP is a progressive inflammatory disorder of the pancreas characteristically resulting in abdominal pain and impairing QOL. Pain due to CP is poorly understood and frequently difficult to treat. This pain has historically been understood as a peripheral process originating from the pancreas itself, but a growing body of literature is revealing an important role offered by central influences. Viewed through the perspective of the biopsychosocial model of illness, cognitive variables strongly influence QOL. However, there is little understanding of variables that influence QOL in CP.

STUDY

Patients with CP from the University of Alabama at Birmingham were administered a 165-question test battery which was comprised of questionnaires evaluating pain beliefs, disease-specific QOL, psychological distress, pain sensation, pain affect, and long-term suffering.

RESULTS

Sixty-eight subjects completed the question battery between February 28, 2011 and January 16, 2014. Almost all (91.2%) reported taking pain medication. QOL was significantly associated with reported levels of pain intensity (r=-0.52, P<0.01) as well as perceived self-blame.

CONCLUSIONS

The significant predictors of QOL impairment in CP are pain intensity and perceived self-blame for pain. Further research is needed to elucidate this relationship while also evaluating the effectiveness of systematic modification of these variables in an attempt to improve pain and QOL in CP.

Age and Disease Duration Impact Outcomes of Total Pancreatectomy and Islet Autotransplant for PRSS1 Hereditary Pancreatitis

OBJECTIVES

We investigated the impact of patient age and disease duration on islet isolation results, diabetes outcomes, and pain outcomes after total pancreatectomy with islet autotransplant (TPIAT) performed in 64 patients with hereditary pancreatitis due to PRSS1 gene mutation.

METHODS

We evaluated the association of patient age and disease duration on islet isolation results and opioid use at 1 year using logistic regression and on graft function using 1-way analysis of variance.

RESULTS

Islet mass was negatively associated with increasing age and longer disease duration, with a 13% reduction (95% confidence interval [CI], 3%-22%) and 22% (95% CI, 14%-29%) reduction in islet equivalents per kilogram body weight (IEQ/kg) for each 5 years of age and disease duration, respectively. Full graft function was associated with younger age and shorter duration of disease (P < 0.01). Persistent opioid use (15% of patients at 1 year) increased with age (P = 0.05) and disease duration (P = 0.04).

CONCLUSIONS

The TPIAT outcomes were adversely impacted by older age and prolonged disease. In particular, islet mass is lower and risk of diabetes high in older patients with prolonged disease. This should be considered when counseling this subgroup of TPIAT recipients on expected outcomes.

A multicenter study of total pancreatectomy with islet autotransplantation (TPIAT): POST (Prospective Observational Study of TPIAT)

BACKGROUND/OBJECTIVES

Total pancreatectomy with islet autotransplantation (TPIAT) is considered for managing chronic pancreatitis in selected patients when medical and endoscopic interventions have not provided adequate relief from debilitating pain. Although more centers are performing TPIAT, we lack large, multi-center studies to guide decisions about selecting candidates for and timing of TPIAT.

METHODS

Multiple centers across the United States (9 to date) performing TPIAT are prospectively enrolling patients undergoing TPIAT for chronic pancreatitis into the Prospective Observational Study of TPIAT (POST), a NIDDK funded study with a goal of accruing 450 TPIAT recipients. Baseline data include participant phenotype, pancreatitis history, and medical/psychological comorbidities from medical records, participant interview, and participant self-report (Medical Outcomes Survey Short Form-12, EQ-5D, andPROMIS inventories for pain interference, depression, and anxiety). Outcome measures are collected to at least 1 year after TPIAT, including the same participant questionnaires, visual analog pain scale, pain interference scores, opioid requirements, insulin requirements, islet graft function, and hemoglobin A1c. Health resource utilization data are collected for a cost-effectiveness analysis. Biorepository specimens including urine, serum/plasma, genetic material (saliva and blood), and pancreas tissue are collected for future study.

CONCLUSIONS

This ongoing multicenter research study will enroll and follow TPIAT recipients, aiming to evaluate patient selection and timing for TPIAT to optimize pain relief, quality of life, and diabetes outcomes, and to measure the procedure's cost-effectiveness. A biorepository is also established for future ancillary studies.

Total Pancreatectomy With Islet Autotransplantation for Acute Recurrent and Chronic Pancreatitis

PURPOSE OF REVIEW

The first total pancreatectomy and islet autotransplantation (TP-IAT) was performed for chronic pancreatitis in 1977 with the goal to ameliorate the pain and simultaneously preserve islet function. We reviewed the recent medical literature regarding indications, patient suitability, current outcomes, and challenges in TP-IAT.

RECENT FINDINGS

Current indications for TP-IAT include intractable pain secondary to chronic pancreatitis (CP) or acute recurrent pancreatitis (ARP) with failed medical and endoscopic/surgical management. Independent studies have shown that TP-IAT is associated with elimination or significant improvement in pain control and partial or full islet graft function in the majority of patients. In single-center cost analyses, TP-IAT has been suggested to be more cost-effective than medical management of chronic pancreatitis. While initially introduced as a surgical option for adults with long-standing chronic pancreatitis, TP-IAT is now often utilized in children with chronic pancreatitis and in children and adults with intractable acute recurrent pancreatitis. The surgical procedure has evolved over time with some centers offering minimally invasive operative options, although the open approach remains the standard. Despite many advances in TP-IAT, there is a need for further research and development in disease diagnosis, patient selection, optimization of surgical technique, islet isolation and quality assessment, postoperative patient management, and establishment of uniform metrics for data collection and multicenter studies. TP-IAT is an option for patients with otherwise intractable acute recurrent or chronic pancreatitis which presents potential for pain relief and improved quality of life, often with partial or complete diabetes remission.

Total pancreatectomy for recurrent acute and chronic pancreatitis: a critical review of patient selection criteria

PURPOSE OF REVIEW

Critical review of the indications for total pancreatectomy and highlight limitations in current diagnostic criteria for chronic pancreatitis.

RECENT FINDINGS

The diagnosis of noncalcific chronic pancreatitis remains controversial because of an overreliance on nonspecific imaging and laboratories findings. Endoscopic ultrasound, s-magnetic resonance cholangiopancreatography, and/or endoscopic pancreatic function testing are often used to diagnose noncalcific chronic pancreatitis despite the fact that there is no gold standard for this condition. Abdominal pain is not specific for chronic pancreatitis and is more likely to be encountered in patients with functional gastrointestinal disorders based on the high incidence of these conditions. The duration of pain and opioid analgesic use results in central sensitization that adversely affects pain outcomes after total pancreatectomy. An alcoholic cause is associated with poorer pain outcomes after total pancreatectomy.

SUMMARY

The lack of a gold standard for noncalcific chronic pancreatitis limits the diagnostic accuracy of imaging and laboratory tests. The pain of chronic pancreatitis is nonspecific and is affected by duration, preoperative opioid use, and cause. These factors will need to be considered in the development of future selection criteria for this morbid surgery.

Treatment response and central pain processing in Anterior Cutaneous Nerve Entrapment Syndrome: An explorative study

BACKGROUND

10-30% of chronic abdominal pain originates in the abdominal wall. A common cause for chronic abdominal wall pain is the Anterior Cutaneous Nerve Entrapment Syndrome (ACNES), in which an intercostal nerve branch is entrapped in the abdominal rectus sheath. Treatment consists of local anaesthetics and neurectomy, and is ineffective in 25% of cases for yet unknown reasons. In some conditions, chronic pain is the result of altered pain processing. This so-called sensitization can manifest as segmental or even generalized hyperalgesia, and is generally difficult to treat.

OBJECTIVE

The aim of this study was to assess pain processing in ACNES patients responsive and refractory to treatment by using Quantitative Sensory Testing, in order to explore whether signs of altered central pain processing are present in ACNES and are a possible explanation for poor treatment outcomes.

METHODS

50 patients treated for ACNES with locally orientated treatment were included. They were allocated to a responsive or refractory group based on their response to treatment. Patients showing an improvement of the Visual Analogue Scale (VAS) pain score combined with a current absolute VAS of <40mm were scored as responsive. Sensation and pain thresholds to pressure and electric skin stimulation were determined in the paravertebral bilateral ACNES dermatomes and at four control areas on the non-dominant side of the body, i.e. the musculus trapezius pars medialis, musculus rectus femoris, musculus abductor hallucis and the thenar. The ACNES dermatomes were chosen to signal segmental hyperalgesia and the sum of the control areas together as a reflection of generalized hyperalgesia. Lower thresholds were interpreted as signs of sensitized pain processing. To test for alterations in endogenous pain inhibition, a conditioned pain modulation (CPM) response to a cold pressor task was determined. Also, patients filled in three pain-related questionnaires, to evaluate possible influence of psychological characteristics on the experienced pain.

RESULTS

Patients refractory to treatment showed significantly lower pressure pain thresholds in the ACNES dermatomes and for the sum of as well as in two individual control areas. No differences were found between groups for electric thresholds or CPM response. Duration of complaints before diagnosis and treatment was significantly longer in the refractory compared to the responsive group, and refractory patients scored higher on the pain-related psychological surveys.

CONCLUSION AND IMPLICATIONS

In this hypothesis-generating exploratory study, ACNES patients refractory to treatment showed more signs of sensitized segmental and central pain processing. A longer duration of complaints before diagnosis and treatment may be related to these alterations in pain processing, and both findings could be associated with less effective locally orientated treatment. In order to validate these hypotheses further research is needed.

REGISTRATION NUMBER

NCT01920880 (Clinical Trials Register; http://www.clinicaltrials.gov).

Prevalence and predictors of pain and opioid analgesic use following total pancreatectomy with islet autotransplantation for pancreatitis

BACKGROUND & OBJECTIVES

Total pancreatectomy with islet autotransplantation (TPIAT) is employed for the management of refractory pain in chronic pancreatitis (CP) with the prospect of partial beta cell preservation. The primary aim of this study is to evaluate the prevalence and predictors of abdominal pain and opioid use following TPIAT.

METHODS

A single center cohort study of all adult patients who underwent TPIAT from 2011 to 2015 for CP. Postoperative pain outcomes included: opioid use, ongoing abdominal pain and new characteristic abdominal pain. Multiple logistic regression analysis was used to evaluate known and potential predictors of postoperative pain outcomes.

RESULTS

During the study period, 46 patients underwent TPIAT. Following surgery, 89% of patients had resolution of their pre-operative abdominal pain; however, 83% of patients developed a new characteristic abdominal pain. Opioid independence was achieved in 46% of patients. Acute recurrent pancreatitis (ARP) (OR: 11.66; 95%CI: 1.47-92.39; p = 0.02) but not pain duration >3 years or ≥ 5 ERCPs was independently associated with resolution of pre-operative abdominal pain on multiple logistic regression. None of these factors were associated with cessation of opioid use.

CONCLUSION

While the majority of patients have resolution of their initial abdominal pain following TPIAT, many will also develop a new characteristic abdominal pain and only half of all patients achieve opioid independence. ARP is the only independent factor associated with positive postoperative pain outcomes and should be considered a standard criterion for patient selection.

Chronic Gastrointestinal Dysmotility and Pain Following Total Pancreatectomy with Islet Autotransplantation for Chronic Pancreatitis

BACKGROUND

The prevalence and impact of chronic gastrointestinal dysmotility following total pancreactectomy with islet autotransplantation (TP-IAT) for chronic pancreatitis is not known.

METHODS

A cross-sectional study of all patients who underwent TP-IAT at our institution from August 2011 to November 2015 was undertaken. The GCSI (Gastroparesis Cardinal Symptom Index), PAGI-SYM (Patient Assessment of Upper Gastrointestinal Disorders-Symptom Severity Index), PAC-SYM (Patient Assessment of Constipation Symptoms), Bristol stool chart, 12-item Short Form Health Survey (SF-12), and visual analog scale for pain were administered ≥4 weeks following TP-IAT.

KEY RESULTS

The prevalence of any dysmotility symptoms in patients who completed the survey (33/45, 73%) post-TP-IAT was 45%. Post-TP-IAT, the mean reduction in opioid dosing was 77.6 oral morphine equivalents (OMEs) (95% CI 32.1-123.0, p = 0.002) with 42% of patients requiring no opioids. There was significant negative correlation between dysmotility scores and SF-12 physical scores (r = -0.46, p = 0.008, 95% CI -0.70 to -0.13). Self-reported abdominal pain had significant negative correlation with both physical and mental SF-12 scores (r = -0.67, p < 0.001, 95% CI -0.83 to -0.41 and r = -0.39, p = 0.03, 95% CI -0.65 to -0.04). There was no correlation between gastrointestinal dysmotility and self-reported pain.

CONCLUSIONS AND INFERENCES

Symptoms of chronic gastrointestinal dysmotility and chronic abdominal pain are common post-TP-IAT and will need to be better recognized and differentiated to improve the management of these patients.

Patient phenotyping in clinical trials of chronic pain treatments: IMMPACT recommendations

There is tremendous interpatient variability in the response to analgesic therapy (even for efficacious treatments), which can be the source of great frustration in clinical practice. This has led to calls for "precision medicine" or personalized pain therapeutics (ie, empirically based algorithms that determine the optimal treatments, or treatment combinations, for individual patients) that would presumably improve both the clinical care of patients with pain and the success rates for putative analgesic drugs in phase 2 and 3 clinical trials. However, before implementing this approach, the characteristics of individual patients or subgroups of patients that increase or decrease the response to a specific treatment need to be identified. The challenge is to identify the measurable phenotypic characteristics of patients that are most predictive of individual variation in analgesic treatment outcomes, and the measurement tools that are best suited to evaluate these characteristics. In this article, we present evidence on the most promising of these phenotypic characteristics for use in future research, including psychosocial factors, symptom characteristics, sleep patterns, responses to noxious stimulation, endogenous pain-modulatory processes, and response to pharmacologic challenge. We provide evidence-based recommendations for core phenotyping domains and recommend measures of each domain.

Chronic Pancreatitis in the 21st Century - Research Challenges and Opportunities: Summary of a National Institute of Diabetes and Digestive and Kidney Diseases Workshop

A workshop was sponsored by the National Institute of Diabetes and Digestive and Kidney Diseases to focus on research gaps and opportunities in chronic pancreatitis (CP) and its sequelae. This conference marked the 20th year anniversary of the discovery of the cationic trypsinogen (PRSS1) gene mutation for hereditary pancreatitis. The event was held on July 27, 2016, and structured into 4 sessions: (1) pathophysiology, (2) exocrine complications, (3) endocrine complications, and (4) pain. The current state of knowledge was reviewed; many knowledge gaps and research needs were identified that require further investigation. Common themes included the need to design better tools to diagnose CP and its sequelae early and reliably, identify predisposing risk factors for disease progression, develop standardized protocols to distinguish type 3c diabetes mellitus from other types of diabetes, and design effective therapeutic strategies through novel cell culture technologies, animal models mimicking human disease, and pain management tools. Gene therapy and cystic fibrosis conductance regulator potentiators as possible treatments of CP were discussed. Importantly, the need for CP end points and intermediate targets for future drug trials was emphasized.

Total Pancreatectomy With Islet Autotransplantation Improves Quality of Life in Patients With Refractory Recurrent Acute Pancreatitis

BACKGROUND & AIMS

Therapeutic options are limited for patients with recurrent acute pancreatitis who have intractable symptoms despite maximal endoscopic and medical treatment, but equivocal or no morphologic or functional evidence of chronic pancreatitis. We performed a prospective observational cohort study to determine the efficacy of total pancreatectomy with islet autotransplantation (TPIAT) for these patients.

METHODS

We collected data from all patients undergoing TPIAT at the University of Minnesota from 2007 through 2013; 49 patients (42 female; mean age, 32.8 ± 7.8 years) had a diagnosis of recurrent acute pancreatitis not provoked by intervention, with negative or equivocal findings from nondiagnostic imaging or pancreatic function tests for chronic pancreatitis, and intractable pain between episodes. Data on insulin use, narcotic requirements, pain scores, and health-related quality of life were collected before TPIAT; 3 months, 6 months, and 1 year afterward; and then yearly.

RESULTS

All 49 patients studied required narcotics before TPIAT (45 daily users and 4 intermittent users); 2 had insulin-treated diabetes. At 1 year after TPIAT, 22 out of 48 patients (46%) reported no use of narcotic pain medications (P < .001 vs baseline). Health-related quality of life score, measured by the physical and mental component summary score, increased by approximately 1 standard deviation from the population mean (P < .001 for the physical component summary; P = .019 for the mental component summary). At 1 year after TPIAT, 21 out of 48 patients (45%) were insulin independent; their mean percent glycosylated hemoglobin A1c at 1 year after TPIAT was 6.0% ± 0.9% (5.2% ± 0.6% pre-TPIAT).

CONCLUSIONS

Patients with recurrent acute pancreatitis but lacking clear chronic pancreatitis benefit from TPIAT, with outcomes similar to those previously described for patients with chronic pancreatitis (improved quality of life and reduced narcotic use). For these patients who have otherwise limited surgical treatment options, TPIAT can be considered when medical and endoscopic therapies have failed.

Management of pain in chronic pancreatitis with emphasis on exogenous pancreatic enzymes

One of the most challenging issues arising in patients with chronic pancreatitis is the management of abdominal pain. Many competing theories exist to explain pancreatic pain including ductal hypertension from strictures and stones, increased interstitial pressure from glandular fibrosis, pancreatic neuritis, and ischemia. This clinical problem is superimposed on a background of reduced enzyme secretion and altered feedback mechanisms. Throughout history, investigators have used these theories to devise methods to combat chronic pancreatic pain including: Lifestyle measures, antioxidants, analgesics, administration of exogenous pancreatic enzymes, endoscopic drainage procedures, and surgical drainage and resection procedures. While the value of each modality has been debated over the years, pancreatic enzyme therapy remains a viable option. Enzyme therapy restores active enzymes to the small bowel and targets the altered feedback mechanism that lead to increased pancreatic ductal and tissue pressures, ischemia, and pain. Here, we review the mechanisms and treatments for chronic pancreatic pain with a specific focus on pancreatic enzyme replacement therapy. We also discuss different approaches to overcoming a lack of clinical response update ideas for studies needed to improve the clinical use of pancreatic enzymes to ameliorate pancreatic pain.

Is Timing of Medical Therapy Related to Outcome in Painful Chronic Pancreatitis?

OBJECTIVES

The authors investigated if timing of medical treatment is associated with the analgesic effect of pregabalin or placebo in patients with chronic pancreatitis (CP).

METHODS

Sixty-four patients received pregabalin (150-300 mg twice a day) or matching placebo for 3 consecutive weeks. Responders to treatment were defined as patients with a reduction in clinical pain scores of 30% or greater. Factors associated with timing of pain treatment (ie, duration of CP and opioid usage) were collected at baseline. In addition, other factors that potentially could influence outcome (eg, clinical pain scores prior to study medication, diabetes, and exocrine pancreatic insufficiency) were also included. Conventional groupwise logistic regression and analysis on the individual patient level with a machine learning technique were used to predict treatment response.

RESULTS

In the conventional statistical analysis duration of CP (odds ratio, 0.9; 95% confidence interval, 0.8-1.1; P = 0.3) and opioid treatment (odds ratio, 1.0; 95% confidence interval, 0.9-1.1; P = 0.6) were not associated with pain relief. In addition, none of the supplementary factors were associated with treatment response (all P > 0.1). Likewise, in the individual patient-level analysis, none of the included variables reached classification accuracies greater than chance level (all P > 0.1).

CONCLUSIONS

Pregabalin can be added as adjuvant analgesic at any time point during the disease course of CP.

Factors Predicting Outcomes After a Total Pancreatectomy and Islet Autotransplantation Lessons Learned From Over 500 Cases

OBJECTIVE

Our objective was to analyze factors predicting outcomes after a total pancreatectomy and islet autotransplantation (TP-IAT).

BACKGROUND

Chronic pancreatitis (CP) is increasingly treated by a TP-IAT. Postoperative outcomes are generally favorable, but a minority of patients fare poorly.

METHODS

In our single-centered study, we analyzed the records of 581 patients with CP who underwent a TP-IAT. Endpoints included persistent postoperative "pancreatic pain" similar to preoperative levels, narcotic use for any reason, and islet graft failure at 1 year.

RESULTS

In our patients, the duration (mean ± SD) of CP before their TP-IAT was 7.1 ± 0.3 years and narcotic usage of 3.3 ± 0.2 years. Pediatric patients had better postoperative outcomes. Among adult patients, the odds of narcotic use at 1 year were increased by previous endoscopic retrograde cholangiopancreatography (ERCP) and stent placement, and a high number of previous stents (>3). Independent risk factors for pancreatic pain at 1 year were pancreas divisum, previous body mass index >30, and a high number of previous stents (>3). The strongest independent risk factor for islet graft failure was a low islet yield-in islet equivalents (IEQ)-per kilogram of body weight. We noted a strong dose-response relationship between the lowest-yield category (<2000 IEQ) and the highest (≥5000 IEQ or more). Islet graft failure was 25-fold more likely in the lowest-yield category.

CONCLUSIONS

This article represents the largest study of factors predicting outcomes after a TP-IAT. Preoperatively, the patient subgroups we identified warrant further attention.

Single center experience in selecting the laparoscopic Frey procedure for chronic pancreatitis

AIM: To share our experience regarding the laparoscopic Frey procedure for chronic pancreatitis (CP) and patient selection.

METHODS: All consecutive patients undergoing duodenum-preserving pancreatic head resection from July 2013 to July 2014 were reviewed and those undergoing the Frey procedure for CP were included in this study. Data on age, gender, body mass index (BMI), American Society of Anesthesiologists score, imaging findings, inflammatory index (white blood cells, interleukin (IL)-6, and C-reaction protein), visual analogue score score during hospitalization and outpatient visit, history of CP, operative time, estimated blood loss, and postoperative data (postoperative mortality and morbidity, postoperative length of hospital stay) were obtained for patients undergoing laparoscopic surgery. The open surgery cases in this study were analyzed for risk factors related to extensive bleeding, which was the major reason for conversion during the laparoscopic procedure. Age, gender, etiology, imaging findings, amylase level, complications due to pancreatitis, functional insufficiency, and history of CP were assessed in these patients.

RESULTS: Nine laparoscopic and 37 open Frey procedures were analyzed. Of the 46 patients, 39 were male (85%) and seven were female (16%). The etiology of CP was alcohol in 32 patients (70%) and idiopathic in 14 patients (30%). Stones were found in 38 patients (83%). An inflammatory mass was found in five patients (11%). The time from diagnosis of CP to the Frey procedure was 39 ± 19 (9-85) mo. The BMI of patients in the laparoscopic group was 20.4 ± 1.7 (17.8-22.4) kg/m² and was 20.6 ± 2.9 (15.4-27.7) kg/m² in the open group. All patients required analgesic medication for abdominal pain. Frequent acute pancreatitis or severe abdominal pain due to acute exacerbation occurred in 20 patients (43%). Pre-operative complications due to pancreatitis were observed in 18 patients (39%). Pancreatic functional insufficiency was observed in 14 patients (30%). Two laparoscopic patients (2/9) were converted. In seven successful laparoscopic cases, the mean operative time was 323 ± 29 (290-370) min. Estimated intra-operative blood loss was 57 ± 14 (40-80) mL. One patient had a postoperative complication, and no mortality was observed. Postoperative hospital stay was 7 ± 2 (5-11) d. Multiple linear regression analysis of 37 open Frey procedures showed that an inflammatory mass (P < 0.001) and acute exacerbation (P < 0.001) were risk factors for intra-operative blood loss.

CONCLUSION: The laparoscopic Frey procedure for CP is feasible but only suitable in carefully selected patients.

Pancreatic pain

PURPOSE OF REVIEW

Pain is the most common symptom of chronic pancreatitis, with a profound socioeconomic impact. Historical management paradigms failed, as they did not adequately address the fundamental underlying mechanisms. The present article describes the neurobiology of pain and sensitization in this condition, in an effort to explain prior failings and provide future directions for managing pain in chronic pancreatitis.

RECENT FINDINGS

A number of recent advances have been made in understanding the neurobiology of pain for this condition. This has been coupled with clinical advances in assessing sensitization to pain in these patients, which has been shown to predict response to medical and surgical therapy.

SUMMARY

Pain in chronic pancreatitis is complex. Addressing the mechanical and morphological findings in chronic pancreatitis without addressing the underlying neurobiological mechanisms is destined to fail. New advances in our understanding of the neurobiology of pain in chronic pancreatitis helps to explain prior failings and provides future direction for managing pain in patients afflicted by this disease.

Chronic pancreatitis pain pattern and severity are independent of abdominal imaging findings

BACKGROUND & AIMS

Chronic pancreatitis is characterized by inflammation, atrophy, fibrosis with progressive ductal changes, and functional changes that include variable exocrine and endocrine insufficiency and multiple patterns of pain. We investigated whether abdominal imaging features accurately predict patterns of pain.

METHODS

We collected data from participants in the North American Pancreatitis Study 2 Continuation and Validation, a prospective multicenter study of patients with chronic pancreatitis performed at 13 expert centers in the United States from July 2008 through March 2012. Chronic pancreatitis was defined based on the detection of characteristic changes by cross-sectional abdominal imaging, endoscopic retrograde cholangiopancreatography, endoscopic ultrasonography, or histology analyses. Patients were asked by a physician or trained clinical research coordinator if they had any abdominal pain during the year before enrollment, those who responded "yes" were asked to select from a list of 5 pain patterns. By using these patterns, we classified patients' pain based on timing and severity. Abnormal pancreatitis-associated features on abdominal imaging were recorded using standardized case report forms.

RESULTS

Data were collected from 518 patients (mean age, 52 ± 14.6 y; 55% male; and 87.6% white). The most common physician-identified etiologies were alcohol (45.8%) and idiopathic (24.3%); 15.6% of patients reported no abdominal pain in the year before enrollment. The most common individual pain pattern was described as constant mild pain with episodes of severe pain and was reported in 45% of patients. The most common imaging findings included pancreatic ductal dilatation (68%), atrophy (57%), and calcifications (55%). Imaging findings were categorized as obstructive for 20% and as inflammatory for 25% of cases. The distribution of individual imaging findings was similar among patients with different patterns of pain. The distribution of pain patterns did not differ among clinically relevant groups of imaging findings.

CONCLUSIONS

Mechanisms that determine patterns and severity of pain in patients with chronic pancreatitis are largely independent of structural variants observed by abdominal imaging techniques. Pancreas-relevant quantitative and qualitative pain measures should be included in the evaluation of patients with chronic pancreatitis to assess pain severity independently of imaging findings.

Systematic mechanism-orientated approach to chronic pancreatitis pain

Pain in chronic pancreatitis (CP) shows similarities with other visceral pain syndromes (i.e., inflammatory bowel disease and esophagitis), which should thus be managed in a similar fashion. Typical causes of CP pain include increased intrapancreatic pressure, pancreatic inflammation and pancreatic/extrapancreatic complications. Unfortunately, CP pain continues to be a major clinical challenge. It is recognized that ongoing pain may induce altered central pain processing, e.g., central sensitization or pro-nociceptive pain modulation. When this is present conventional pain treatment targeting the nociceptive focus, e.g., opioid analgesia or surgical/endoscopic intervention, often fails even if technically successful. If central nervous system pain processing is altered, specific treatment targeting these changes should be instituted (e.g., gabapentinoids, ketamine or tricyclic antidepressants). Suitable tools are now available to make altered central processing visible, including quantitative sensory testing, electroencephalograpy and (functional) magnetic resonance imaging. These techniques are potentially clinically useful diagnostic tools to analyze central pain processing and thus define optimum management approaches for pain in CP and other visceral pain syndromes. The present review proposes a systematic mechanism-orientated approach to pain management in CP based on a holistic view of the mechanisms involved. Future research should address the circumstances under which central nervous system pain processing changes in CP, and how this is influenced by ongoing nociceptive input and therapies. Thus we hope to predict which patients are at risk for developing chronic pain or not responding to therapy, leading to improved treatment of chronic pain in CP and other visceral pain disorders.

Chronic pancreatitis

PURPOSE OF REVIEW

We review selected important clinical observations in chronic pancreatitis reported in 2013.

RECENT FINDINGS

Early diagnosis of chronic pancreatitis remains difficult, although newer techniques utilizing endoscopic ultrasonography-elastography and MRI hold promise. Patients with chronic pancreatitis are at risk of nutritional deficiencies. Osteoporosis, osteopenia, and bone fracture are particularly common in these patients, and require active intervention and treatment. Diabetes caused by chronic pancreatitis, type 3c diabetes, has specific characteristics and requires careful management. Antioxidants and neuromodulators may decrease pain in some patients with chronic pancreatitis. Endoscopic treatment is effective and can be utilized in patients with painful chronic pancreatitis, although randomized trials demonstrate that surgical therapy is somewhat more durable and effective. Although surgery has typically been a last resort, some advocate early surgical intervention but the optimal time remains unknown.

SUMMARY

Early diagnosis of pancreatitis may be improved by newer techniques associated with endoscopic ultrasonography imaging. Treatment of nutritional deficiencies and diabetes is an important aspect of treating chronic pancreatitis. Pain relief with adjunct means of pain modulation should be tried before starting narcotics for pain control. Endoscopic therapy is appropriate for treating chronic pancreatitis and its local complications and surgical intervention can be considered early in carefully selected individuals.