British Journal of Pain

Phantom limb pain (PLP) is a complex condition resulting in pain in the missing limb affecting 60–80% amputees. Increasing number of patients are undergoing amputations. Approximately 1 per every 1000 people in the United Kingdom is an amputee. Incidence of PLP can be as high as 80% following amputation. PLP can be severe and difficult to treat. A range of pharmacological interventions exist yet little is known about them in respect to PLP. This article will address the effectiveness of both single pharmacological, therapy as well as drug combination therapy.

We reviewed all literature looking at the evidence for the efficacy of both single and combined pharmacological therapy in the management of phantom limb pain. Not all commonly prescribed analgesic agents have been studied in the use of PLP and in these cases, the evidence of their efficacy in neuropathic pain was reviewed

It is difficult to draw definitive conclusions on the pharmacological management of PLP based on current available evidence. Most trials involved small cohorts and were not specific to the PLP. The trials which looked specifically at the PLP population gave conflicting results. Only the N-methyl-d-aspartate (NMDA) receptor antagonist class demonstrated consistent positive results. Most notably ketamine did produce a reduction in pressure pain thresholds and pain windup associated with PLP, although the numbers in these studies remain small. This benefit was not demonstrated across all NMDA receptor antagonists. Combination therapy has demonstrated effectiveness in previous studies for neuropathic pain but this has never been tested specifically against a PLP cohort. Therefore, combination treatment of agents with proven efficacy in PLP such as opioid and gabapentin deserves a closer examination in a controlled study against a placebo as well as single drug therapy

The double stopwatch (DSW) method for determining the onset of analgesic activity has been implemented extensively by investigators studying orally administered drugs.

The aim of this randomised, placebo-controlled trial was to use the DSW method to determine the time to onset of analgesia of a single dose of a topically administered non-steroidal anti-inflammatory drug, flurbiprofen 8.75 mg lozenge.

Adults with acute sore throat (n = 122) were examined to confirm the presence of tonsillopharyngitis (Tonsillo-Pharyngitis Assessment) and sore throat pain of at least moderate intensity (≥6 on a 0–10 Sore Throat Scale). Lozenges containing flurbiprofen 8.75 mg or inert ingredients (identically flavoured) were administered under double-blind conditions in the clinic while patients assessed pain and pain relief over 3 hours. Onset of analgesia was determined using the DSW method and reported as the Kaplan–Meier median time to meaningful relief. The median time to first perceived relief was also documented.

About 78% of flurbiprofen-treated patients reported meaningful pain relief compared with 48% of placebo-treated patients (p < 0.01); median time to meaningful relief for flurbiprofen-treated patients was 43 minutes (placebo-treated patients were right-censored due to non-responsivity; p = 0.01). Median time to first perceived pain relief was 11 minutes for flurbiprofen-treated patients and 19 minutes for placebo-treated patients (p = 0.03). Flurbiprofen lozenge was well tolerated, with no serious adverse events occurring and no patient discontinuing due to an adverse event.

These results indicate that the DSW method can be successfully applied to the evaluation of the onset of action of a locally administered analgesic in patients with acute sore throat, demonstrating that the onset of action (time to meaningful pain relief) of flurbiprofen lozenge was <45 minutes.

High-frequency (HF) spinal cord stimulation (SCS), a relatively new form of spinal cord stimulation, provides stimulation frequencies of up to 10 kHz and allows for paresthesia-free pain relief, an advantage that distinguishes it from traditional stimulation therapy. Without paresthesias, patients with HF SCS do not experience position-dependent painful stimulation and do not have to experience treatment interruption during sleep. Lead migration is a well-known complication of conventional spinal cord stimulation and usually results in a loss of efficacy along with other unpleasant sensory symptoms. In this case report, we present an incidence of lead migration in HF SCS that resulted in paresthesias, a symptom not expected to occur in this novel therapy.

The patient, a 60-year-old female with post-laminectomy syndrome, underwent a trial of HF SCS with standard lead placement at T8-T9. She initially had pain relief, but returned to the office on post-operative day 2 complaining of left chest wall and cardiac paresthesias, without frank pain or palpitations, in addition to loss of efficacy for her back and leg pain. Imaging showed that the leads had migrated, with one lead reaching the levels of T1-T3.

While HF SCS has emerged as an effective paresthesia-free means of reducing back and leg pain, we provide the first report of paresthesias occurring with the HF SCS system as a result of cephalad lead migration. As HF SCS is only now being utilized as a treatment modality, we must remain cautious of potential adverse outcomes in patients, in particular above T8.

The Lothian Chronic Pain Service relocated from a university teaching hospital (Western General Hospital (WGH)) to a community centre (Leith Community Treatment Centre (LCTC)) in 2015. Transportation and geographical location were noted by staff to be potential challenges that could negatively impact on the patient experience. The objective of this study is to evaluate how relocating pain clinic from an urban-based hospital to a peripheral community centre on patient experience.

An assessment and audit of the impact of the relocation on the Patient-Reported Experience Measure (PREM) of pain services was conducted. Using a nationally developed questionnaire, the patient-reported experience from LCTC was prospectively collected in 2016 and was compared to historical data obtained from WGH in 2014 by National Health Service (NHS) Scotland. All patients attending Lothian Chronic Pain Service clinics were deemed eligible for the audit. Patient demographics were compared between the two data sets. The impact of patient deprivation on patient experience was investigated using the Scottish Index of Multiple Deprivation (SIMD16).

Data from 111 patients from LCTC were compared to 206 patients from WGH. Percentage of patients rating care as ‘excellent’ was found to be significantly greater at LCTC than WGH (0.0049). However, overall patient rating of care from LCTC was not significantly different from WGH data and ratings were higher at LCTC. No correlation was found between patient deprivation and PREM.

There is no clear evidence that PREM was negatively affected by the move from a university teaching hospital to a community setting. As this only reported experiences of patients who attended the service, further studies may be warranted to investigate the impact of patient nonattendance.

Chronic pelvic pain (CPP) is estimated to affect 6%–27% of women worldwide. In the United Kingdom, over 1 million women suffer from CPP and it has been highlighted as a key area of unmet need. Standard treatments are associated with unacceptable side effects. The meridian balance method electro-acupuncture (BMEA), and traditional Chinese medicine health consultation (TCM HC) (BMEA + TCM HC = BMEA treatment) may be an effective adjunct to standard treatment.

The aim of our study was to evaluate the feasibility of a future trial, to determine the effectiveness of the BMEA treatment for CPP in women. The primary objectives were to determine recruitment and retention rates. The secondary objectives were to assess the effectiveness of the BMEA treatment and acceptability of the study’s methodology.

Women with CPP were randomised into BMEA treatment (group 1), TCM HC alone (group 2) (each intervention administered twice weekly for 4 weeks) or National Health Service standard care (NHS SC, group 3). Primary outcomes were assessed by the proportion of eligible participants randomised, and the proportion of randomised participants who returned follow-up questionnaires. Interventions were assessed by validated pain/physical/emotional functioning questionnaires at baseline (0), 4, 8 and 12 weeks. Focus groups and semi-structured telephone interviews were embedded in the study.

A total of 30 women (51% of those referred) were randomised over 8 months. Retention rates were 80% (95% confidence interval (CI): 74–96), 53% (95% CI: 36–70) and 87% (95% CI: 63–90), in groups 1, 2, and 3, respectively. Qualitative data suggested a favourable trial experience in groups 1 and 3.

Group 2 retention rate was problematic and has implications for our next trial.

Our study suggests that a future trial to determine the effectiveness of BMEA treatment for women with CPP is feasible but with modifications to the study design.

Fibromyalgia is a chronic musculoskeletal pain condition that is often associated with sleep disturbances and fatigue. The pathophysiology of fibromyalgia is not understood, but indirect evidence suggests a central dysfunction of the nociceptive modulating system. The aim of this study was to evaluate whether quantitative sensory testing detects a change in pain thresholds in fibromyalgia patient receiving pregabalin treatment.

A total of 25 patients were recruited for the study and received routine pregabalin, but only 14 patients completed the treatment. Assessment of pressure pain thresholds and changes in conditioned pain modulation using ischaemic pain as a conditioning stimulus were measured at baseline and every 4 weeks for 12 weeks. Fibromyalgia impact questionnaire, PainDETECT and SF-12 were also completed.

Patients with fibromyalgia demonstrated a less-efficient conditioned pain modulation at baseline. An efficient conditioned pain modulation was observed at 1 month and this was maintained until the final visit. Pressure pain thresholds (PPTs) showed a significant improvement from baseline. Patients also reported a similar magnitude of improvements in PainDETECT, fibromyalgia impact questionnaire (FIQ) and its impact on daily life and change in outcome for SF-12.

This pilot study reports an increase in PPTs and improved conditioned pain modulation response after commencing pregabalin, which was maintained at 12 weeks, and this was supported by positive pain scores. Pregabalin is a licenced treatment for fibromyalgia in Europe, and its response to central sensitisation, particularly ‘dynamic responses’, has not been reported. We conclude that pregabalin has the potential to reduce peripheral and central sensitisation in patients with fibromyalgia, as measured using quantitative sensory testing.