Lidocaine Patch (5%) in Treatment of Persistent Inguinal Postherniorrhaphy Pain

Abstract

Background: Evidence-based pharmacological treatment options for patients with persistent inguinal postherniorrhaphy pain are lacking. Methods: Twenty-one male patients, with severe, unilateral, persistent inguinal postherniorrhaphy pain, participated in a randomized, double-blind, placebo-controlled crossover trial, receiving lidocaine patch (5%) and placebo patch treatments in periods of 14 days separated by a 14-day wash-out period. Pain intensities (at rest, during movement, and pressure evoked [Numerical Rating Scale]) were assessed before treatment and on the last 3 days of each treatment period. Patients were a priori divided into two subgroups based on quantitative sensory testing (+/− thermal "hyposensitivity"). Skin biopsies for intraepidermal nerve fiber density assessment were taken at baseline, and quantitative sensory testing was performed before and after each treatment period. The primary outcome was change in pain intensity assessed as the difference in summed pain intensity differences between lidocaine and placebo patch treatments. Results: There was no difference in summed pain intensity differences between lidocaine and placebo patch treatments in all patients (mean difference 6.2% [95% CI = −6.6 to 18.9%]; P = 0.33) or in the two subgroups (+/− thermal "hyposensitivity"). The quantitative sensory testing (n = 21) demonstrated an increased pressure pain thresholds after lidocaine compared with placebo patch treatment. Baseline intraepidermal nerve fiber density (n = 21) was lower on the pain side compared with the nonpain side (−3.8 fibers per millimeter [95% CI = −6.1 to −1.4]; P = 0.003). One patient developed mild erythema in the groin during both treatments. Conclusions: Lidocaine patch treatment did not reduce combined resting and dynamic pain ratings compared with placebo in patients with severe, persistent inguinal postherniorrhaphy pain.

The effect of oxcarbazepine in peripheral neuropathic pain depends on pain phenotype: A randomised, double-blind, placebo-controlled phenotype-stratified study

“…This is in line with results from recent studies on topical lidocaine that showed a tendency toward better effect of this topical sodium channel blocker in patients with preserved cold or thermal sensation [6,19]. Recently, a trial in painful diabetic neuropathy found that patients who showed a pain response to a topical capsaicin challenge also had slightly better pain relief following topical clonidine, which blocks a 2 -adrenergic receptors, although part of this difference seemed to be explained by a difference in placebo response [8].…”

“…Numbers needed to treat (NNT) for more than 50% pain relief was 7.0 (95% CI 4. in the total population, 3.9 (95% CI 2. [3][4][5][6][7][8][9][10][11][12] in the IN, and 13 (95% CI 5.2-1) in the NIN group. Pain relief as measured by the specific scale was significantly better for oxcarbazepine compared with placebo in the total group (0.9 point, P < 0.001), but with no significant phenotype treatment interaction (0.3 point, P = 0.21).…”

Systematic review of management of chronic pain after surgery

“…Eleven trials including data from 324 participants assessed the effectiveness of local anaesthetics in providing pain relief after inguinal hernia repair, spinal surgery, amputation and breast cancer surgery. Risk of bias was evident in three studies, and concerned incomplete outcome data, random sequence generation and blinding, and early trial termination.…”

The 5% Lidocaine-Medicated Plaster: Its Inclusion in International Treatment Guidelines for Treating Localized Neuropathic Pain, and Clinical Evidence Supporting its Use

“…Prospective, observational study in trauma patients with LNP of >3 months’ duration196.7 (NRS)1/2 plaster in one patient, 1/4 plaster in 18 patientsMean duration 19.5 weeksMean pain intensity decreased to 2.8 (reduction of 58.2%). Mean painful area decreased from 17.8 to 2.1 cm 2 (reduction of 87.6%)Bischoff et al [84]. Randomized, double-blind, placebo-controlled crossover trial216 at rest, 7 during movement, 8 during palpation (NRS)114 days with either lidocaine or placebo plaster/14-day washout period/14 days with alternative plasterChanges in pain intensity following treatment with lidocaine or placebo (summed pain intensity differences—SPID) were not significantly differentLikar et al [85].…”

“…Clinical Global Impression of Change (CGIC) scores of ‘Much Improvement’ or ‘Very Much Improvement’ were recorded for 76% of the patients (Table 2), including all the patients (17%) who had received the plaster as monotherapy [83]. However, lidocaine plasters did not reduce combined resting and dynamic pain ratings in 21 patients with severe, persistent inguinal postherniorrhaphy pain compared with placebo [84]. …”