British Journal of Pain

The pain of chronic pancreatitis represents a major challenge to those working in the field, including pain specialists, gastroenterologists and surgeons. This article describes the different aetiologies of chronic pancreatitis and lists the models for the pathogenesis of pain, including novel ideas such as the role of the immune system in the modulation of pain. The patient profile in chronic pancreatitis is discussed along with the social impact of the disease in relation to alcohol misuse.

The range of treatment strategies including medical, endoscopic and surgical approaches are evaluated. Common analgesic regimes and their limitations are reviewed.

The pain of chronic pancreatitis remains refractory to effective treatment in many cases and further study and understanding of the underlying pathophysiology are required.

Pain related to cardiac disease has been recognised for centuries. However, the precise mechanisms of angina pectoris remain bafflingly obscure. Conventional cardiological angina management concentrates on methods to improve oxygen delivery to cardiac myocytes as our understanding of cardiac muscle cells’ response to hypoxia increases. In common with other chronic visceral pain syndromes, little is understood about how pain signals are generated and propagated by visceral nerves. Improved imaging and other physiological assessments have demonstrated important central nervous system (CNS) responses to myocardial ischaemia, including activation of CNS areas known to be ‘key players’ in chronic pain syndromes. Patients with stable angina usually have an excellent prognosis, especially if left ventricular function is preserved. Educating patients about their condition, teaching simple techniques known to help chronic pain patients and introducing targeted pain treatments specific to angina can be extremely helpful adjuncts to conventional cardiological treatments and will often bring about significant improvements in quality of life.

Endometriosis is an enigmatic disease and its fundamental cause is still unknown. Endometriosis-associated pain syndrome is a common problem; it is underdiagnosed and patients suffering from the syndrome are rarely seen in specialist pain clinics. The correlation between the extent of the disease and pain is weak. Endometriosis-associated pain syndrome may be cyclical or persistent and the pain may radiate to other pelvic organs. Optimum treatment is timely intervention using a multidisciplinary approach.

Visceral pain is a highly complex entity whose experience is variable in health and disease. It can occur in patients with organic disease and also in those without any readily identifiable structural or biochemical abnormality such as in the functional gastrointestinal disorders (FGID). Despite considerable progress in our understanding of the culpable underlying mechanisms significant knowledge gaps remain, representing a significant unmet need in gastroenterology. A key, but not universal, pathological feature is that patients with FGID often display heightened sensitivity to experimental gut stimulation, termed visceral hypersensitivity. A plethora of factors have been proposed to account for this epiphenomenon including peripheral sensitization, central sensitization, aberrant central processing, genetic, psychological and abnormalities within the stress responsive systems. Further research is needed, bringing together complementary research themes from a diverse array of academic disciplines ranging from gastroenterology to nociceptive physiology to functional neuro-imaging, to address this unmet need.

1. The group of patients with so-called ‘failed back surgery syndrome’ (FBSS) is very diverse. Published studies evaluating the outcome of surgical treatment vary widely in terms of surgical interventions that were performed. Results from these papers cannot be generally applied to all people who have persisting complaints after low back surgery.

2. The literature search that was performed demonstrated that the articles that scored as acceptable on assessment bias demonstrated a low to moderate patient-perceived recovery percentage. The only randomized controlled trial on this topic did not demonstrate a difference between instrumented fusion and cognitive intervention and exercise.

3. Current research does not show repeat surgery to be successful in ‘FBSS patients’, but clinical practice indicates that, in a small, carefully selected group, repeat surgery can yield rewarding results. However, parameters that make a patient prone to recover from a subsequent surgical intervention cannot be found in the literature.

4. The term ‘failed back surgery syndrome’ implies a causative role of surgery in a problem situation; failed back surgery syndrome is frequently regarded as failed back surgery. The literature does not, however, provide evidence for this.

5. It is important to inform the patient adequately to shape realistic expectations. Preoperative evaluation of parameters evaluating the psychological condition could help to better predict the outcome of surgery.

6. The term ‘failed back surgery syndrome’ has been demonstrated to be an ill-defined term, serving as a container for all kinds of back and leg problems, and wrongly implying a definite role for the surgical intervention in the aetiology. We suggest shifting the paradigm to ‘failed back syndrome’. With this term we suggest defining those patients with back and radicular leg pain without a structural deficit, or with a structural deficit that has a low a priori chance of benefiting from a surgical intervention.

Failed back surgery syndrome is an unhelpful term that hides the true issues concerning the mechanism of pain and subsequent therapies that patients with chronic radicular neuropathic pain are exposed to. Patients with chronic radicular neuropathic pain who have had previous spinal surgery are numerous and comparable in prevalence and incidence to other pain associated diseases such as rheumatoid arthritis but with higher annual costs. Better recognition of this patient group with the effective recognition and multi-disciplinary care aimed at achieving best patient and societal outcomes is required.