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Somatosensory Outcomes Following Re-Surgery in Persistent Severe Pain After Groin Hernia Repair : A Prospective Observational Study

Jensen, Elisabeth Kjær ; Ringsted, Thomas K. ; Bischoff, Joakim M. ; Petersen, Morten A. ; Møller, Kirsten ; Kehlet, Henrik and Werner, Mads U. LU (2023) In Journal of Pain Research 16. p.943-959
Abstract

Purpose: After groin hernia repair (globally more than 20 million/year) 2–4% will develop persistent severe pain (PSPG). Pain management is challenging and may require multimodal interventions, including re-surgery. Quantitative somatosensory testing (QST) is an investigational psychophysiological tool with the potential to uncover the pathophysiological mechanisms behind the pain, ie, revealing neuropathic or inflammatory components. The primary objective was to examine and describe the underlying pathophysiological changes in the groin areas by QST before and after re-surgery with mesh removal and selective neurectomy. Patients and Methods: Sixty patients with PSPG scheduled for re-surgery and with an inflammatory “component”... (More)

Purpose: After groin hernia repair (globally more than 20 million/year) 2–4% will develop persistent severe pain (PSPG). Pain management is challenging and may require multimodal interventions, including re-surgery. Quantitative somatosensory testing (QST) is an investigational psychophysiological tool with the potential to uncover the pathophysiological mechanisms behind the pain, ie, revealing neuropathic or inflammatory components. The primary objective was to examine and describe the underlying pathophysiological changes in the groin areas by QST before and after re-surgery with mesh removal and selective neurectomy. Patients and Methods: Sixty patients with PSPG scheduled for re-surgery and with an inflammatory “component” indicated by blunt pressure algometry were examined in median (95% CI) 7.9 (5.8–11.5) months before and 4.0 (3.5–4.6) months after re-surgery. The QST-analyses included standardized assessments of cutaneous mechanical/thermal detection and pain thresholds. Suprathreshold heat stimuli were applied. Deep tissue sensitivity was tested by pressure algometry. Testing sites were the groin areas and the lower arm. Before/after QST data were z-transformed. Results: Re-surgery resulted in median changes in rest, average, and maximal pain intensity scores of −2.0, −2.5, and −2.0 NRS (0/ 10) units, respectively (P = 0.0001), and proportional increases in various standardized functional scores (P = 0.0001). Compared with the control sites, the cutaneous somatosensory detection thresholds of the painful groin were increased before re-surgery and increased further after re-surgery (median difference: 1.28 z-values; P = 0.001), indicating a successive post-surgical loss of nerve fiber function (“deafferentation”). Pressure algometry thresholds increased after re-surgery (median difference: 0.30 z-values; P = 0.001). Conclusion: In this subset of patients with PSPG who underwent re-surgery, the procedure was associated with improved pain and functional outcomes. While the increase in somatosensory detection thresholds mirrors the surgery-induced cutaneous deafferentation, the increase in pressure algometry thresholds mirrors the removal of the deep “pain generator”. The QST-analyses are useful adjuncts in mechanism-based somatosensory research.

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author
; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
chronic post-surgical pain, groin, hernia repair, reoperation, sensory thresholds
in
Journal of Pain Research
volume
16
pages
17 pages
publisher
Dove Medical Press Ltd.
external identifiers
  • pmid:36960467
  • scopus:85151162870
ISSN
1178-7090
DOI
10.2147/JPR.S384973
language
English
LU publication?
yes
id
ec687728-7631-4a44-b9f0-385c89b0756b
date added to LUP
2023-05-24 13:46:36
date last changed
2024-04-19 22:13:32
@article{ec687728-7631-4a44-b9f0-385c89b0756b,
  abstract     = {{<p>Purpose: After groin hernia repair (globally more than 20 million/year) 2–4% will develop persistent severe pain (PSPG). Pain management is challenging and may require multimodal interventions, including re-surgery. Quantitative somatosensory testing (QST) is an investigational psychophysiological tool with the potential to uncover the pathophysiological mechanisms behind the pain, ie, revealing neuropathic or inflammatory components. The primary objective was to examine and describe the underlying pathophysiological changes in the groin areas by QST before and after re-surgery with mesh removal and selective neurectomy. Patients and Methods: Sixty patients with PSPG scheduled for re-surgery and with an inflammatory “component” indicated by blunt pressure algometry were examined in median (95% CI) 7.9 (5.8–11.5) months before and 4.0 (3.5–4.6) months after re-surgery. The QST-analyses included standardized assessments of cutaneous mechanical/thermal detection and pain thresholds. Suprathreshold heat stimuli were applied. Deep tissue sensitivity was tested by pressure algometry. Testing sites were the groin areas and the lower arm. Before/after QST data were z-transformed. Results: Re-surgery resulted in median changes in rest, average, and maximal pain intensity scores of −2.0, −2.5, and −2.0 NRS (0/ 10) units, respectively (P = 0.0001), and proportional increases in various standardized functional scores (P = 0.0001). Compared with the control sites, the cutaneous somatosensory detection thresholds of the painful groin were increased before re-surgery and increased further after re-surgery (median difference: 1.28 z-values; P = 0.001), indicating a successive post-surgical loss of nerve fiber function (“deafferentation”). Pressure algometry thresholds increased after re-surgery (median difference: 0.30 z-values; P = 0.001). Conclusion: In this subset of patients with PSPG who underwent re-surgery, the procedure was associated with improved pain and functional outcomes. While the increase in somatosensory detection thresholds mirrors the surgery-induced cutaneous deafferentation, the increase in pressure algometry thresholds mirrors the removal of the deep “pain generator”. The QST-analyses are useful adjuncts in mechanism-based somatosensory research.</p>}},
  author       = {{Jensen, Elisabeth Kjær and Ringsted, Thomas K. and Bischoff, Joakim M. and Petersen, Morten A. and Møller, Kirsten and Kehlet, Henrik and Werner, Mads U.}},
  issn         = {{1178-7090}},
  keywords     = {{chronic post-surgical pain; groin; hernia repair; reoperation; sensory thresholds}},
  language     = {{eng}},
  pages        = {{943--959}},
  publisher    = {{Dove Medical Press Ltd.}},
  series       = {{Journal of Pain Research}},
  title        = {{Somatosensory Outcomes Following Re-Surgery in Persistent Severe Pain After Groin Hernia Repair : A Prospective Observational Study}},
  url          = {{http://dx.doi.org/10.2147/JPR.S384973}},
  doi          = {{10.2147/JPR.S384973}},
  volume       = {{16}},
  year         = {{2023}},
}