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Background: Severe, persistent inguinal postherniorrhaphy pain (PIPP) is a debilitating condition that develops in 2-5% of patients. PIPP may be neuropathic in nature, yet the lesion in the peripheral nervous system has not been located. Most PIPP-patients demonstrate a tender point (TP) in the medial aspect of the inguinal region that triggers pain upon minimal pressure. As TPs may play a role in the pathophysiology of PIPP, the aim of this trial was to investigate the analgesic effects of local anaesthetic TP-blockade.Methods: A randomized, double-blind, placebo-controlled, crossover trial was performed in 14 PIPP-patients and six healthy volunteers. All participated in two sessions, seven days apart, receiving 10 ml of 0.25% bupivacaine or normal saline via an ultrasound-guided fascial plane block at the TP. The TP-area was used for pain assessments (at rest, on movement, with 100 kPa pressure-algometry) and quantitative sensory testing (pressure pain thresholds, thermal detection/pain thresholds, supra-threshold heat perception), before and after the TP-blockade.Results: The median (95% CI) reduction in pain was 63% (44.1 to 73.6%) after bupivacaine compared with 36% (11.6 to 49.7%; P=0.003) after placebo. Significant increases in cool detection (P=0.01) and pressure pain thresholds (P=0.009) with decreases in supra-threshold heat pain perception (P=0.003) were seen after bupivacaine only. In four out of six volunteers, increased thermal and evoked-pain thresholds after bupivacaine compared with placebo, was demonstrated.Conclusions: This trial demonstrates that peripheral afferent input from the TP-area is important for maintenance of spontaneous and evoked pain in PIPP.Clinical Trial Registration: NCT02065219. [ABSTRACT FROM AUTHOR]

Background Video-assisted thoracic surgery (VATS) lobectomy may potentially reduce the risk of post-thoracotomy pain syndrome (PTPS). However, it may still carry a risk of intraoperative nerve damage and thereby development of PTPS. Thus, our aim was to present a detailed long-term neurophysiological characterization of PTPS after VATS. Methods Quantitative sensory testing, using thermal and mechanical stimuli, was performed in 13 PTPS patients and 35 pain-free patients recruited 33 months after VATS lobectomy. Results When comparing the operated side with the control side in PTPS patients, increased thresholds of tactile and warmth detection were observed, while in pain-free patients, increased thresholds of warmth detection, cool detection, and heat pain were demonstrated. At the anterior porthole, pain-free patients displayed increased threshold to thermal detection when compared with the control side. Only side-to-side difference for tactile detection threshold was increased in PTPS patients compared with pain-free patients. Assessment of central sensitization showed no significant differences within or between PTPS and pain-free patients nor did group comparison of area of hypo- and hyperaesthesia to cool. Anxiety and depression scores (HADS) were higher in PTPS patients, but the area of hyper- and hypoaesthesia did not differ significantly between HADS groups. Conclusions Increased sensory thresholds suggest nerve injury to be present on the operated side in both PTPS and pain-free patients. However, no significant quantitative differences between PTPS and pain-free patients could be found, implicating the presence of factors other than intercostal nerve injury as important for development of PTPS after VATS lobectomy. [ABSTRACT FROM PUBLISHER]