Persistent severe pain occurring in the aftermath of a surgical procedure is frequently associated with significant impairment of physical and psycho-social functions. After groin hernia repair (GHR), 2-4% of patients develop persistent severe pain. The GHR procedure, previously considered belonging to minor surgeries, qualifies as a rather complex procedure performed in a territory with a high density of nerve fibers, accommodating essential functions for locomotion and reproduction. More than 20 million repairs are performed annually worldwide, and consequently, it is estimated that 400.000-800.000 patients each year will develop persistent severe pain after the groin hernia repair (PSPG). Management of PSPG is medically challenging and may require re-surgery with mesh removal and selective neurectomy. After re-surgery for pain after open primary GHR, a potential pain-relieving effect, as well as an improvement of the deteriorated physical functions, has been demonstrated.~Quantitative somatosensory testing (QST) is an investigational psychophysiological tool with the potential to uncover the putative pathophysiological substrate in PSPG, i.e., neuropathic and inflammatory constituents. The method may also be used to quantitate changes induced by the re-surgery. Since re-surgery is a neuroablative procedure, essentially performed in previously damaged tissue, it is of interest to examine the extent of neurological perturbations, i.e., 'loss' and 'gain' of sensory functions and the relation to clinical outcome measures.~The authors are only aware of one previous PSPG-study (n = 21) finding that re-surgery, including meshectomy and selective neurectomy, was associated with increased pain pressure thresholds, decreased pain ratings and improved pain-related functional measures. The objectives of the current study, comparing pre with post-re-surgery data, were first to perform a more detailed analysis of the quantitative somatosensory data regarding 'loss' and 'gain' of sensory functions and their relation to clinical outcome measures. Second, to corroborate the clinical outcome findings of the previous study using a threefold larger cohort.
Groin hernia repair is accompanied by persistent severe pain in 2-4% of the patients significantly restraining psychophysical functions. Re-surgery with meshectomy and selective neurectomy may improve the pain condition, compared to non-surgical alternatives. In the current study, the primary objective was to examine and describe the underlying pathophysiological perturbations by quantitative somatosensory testing before and after re-surgery.