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Completed

NCT Number: NCT05238571

Does Re-surgery Improve Somatosensory Outcomes in Persistent Pain After Groin Hernia Repair

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.

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Key information

Conditions

Patients With Persistent Severe Pain After Groin Hernia Repair Neurologic Manifestations Pain Pain, Postoperative Pathologic Processes Pathological Conditions, Signs and Symptoms Postoperative Complications Signs and Symptoms

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

Multidisciplinary Pain Center, Neuroscience Center, Copenhagen University Hospital, DENMARK

Copenhagen, 2100, Denmark

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Patients with persistent severe pain (activity-related or maximal pain intensity > 7 NRS-scores [numeric pain rating scale 0-10]) following unilateral, uncomplicated, open groin hernia repair.

Exclusion criteria

  • All that contradicts the above.

Treatment and study plan

Re-surgery

Procedure

Re-surgery with meshectomy and selective neurectomy

Primary outcomes

  1. Thermal thresholds

    Time frame: 3-6 months

    Warmth detection threshold (WDT), cool detection threshold, heat pain threshold (HPT) and cold pain threshold (CPT) are made by a computerized contact thermode (Thermotest, Somedic AB, Sweden) with an active thermal surface of 12.5 cm^2 (2.5 x 5.0 cm^2). The thresholds are determined from a baseline temperature of 32°C with a ramp rate of + 1°C/s. Cut-offs for heat and cold are 50°C and 5°C, respectively. The assessments are made in triplicate and the mean values are used in the statistical analyses.

  2. Pressure algometry

    Time frame: 3-6 months

    Deep-tissue pain sensitivity is assessed using a hand-held pressure algometer with a neoprene-coated tip of area 1.0 cm2 (Somedic AB, Sweden), as previously described. The algometer is applied perpendicularly to the skin with a pressure rate of 30 kPa/s. The study subject is told to report the pressure pain threshold (PPT) by activating the button device when pain is perceived. The cut-off limit is 350 kPa. Testing is done in triplicate and the average value is used in the statistical analyses.

  3. Suprathreshold heat stimulation

    Time frame: 3-6 months

    A short tonic heat stimulus (heating area 12.5 cm^2; ramp rate: 1°C/s, plateau: 47°C, 5 s; STH) is delivered in order to evaluate the suprathreshold heat pain perception (NRS).

  4. Temporal summation

    Time frame: 3-6 months

    Temporal summation test, i.e., the perception in response to repetitive (0.3 to 3 Hz) mechanical stimulation [i.e., wind-up like pain: WUP], indicates presence of central sensitization. The repetitive 1 Hz stimuli for 60 s are either dynamically delivered by a brush or statically delivered by a polyamide filament (one nominal rank below TPT). The study subjects are told to report the level of pain (NRS) every 15 s-1 during the stimulation. Signs of aftersensations are followed 60 s after discontinuation of the stimulation, and the intensity of discomfort or pain is rated by NRS.

Secondary outcomes

  1. Activity Assessment Scale (AAS)

    Time frame: 3-6 months

    Changes in AAS scores before and thre-six months after operation

  2. Pain intensity scores (NRS)

    Time frame: 3-6 months

    Changes in pain intensity scores (NRS) at rest, on average and maximally before and thre-six months after operation

Sponsors and collaborators

Lead sponsor

mads u werner

Other

Registry information

Official study title

Somatosensory Outcomes Following Re-surgery in Persistent Severe Pain After Groin Hernia Repair

Important dates

Study start
2009
Primary completion
2015
Study completion
2015
First posted
Feb 14, 2022
Registry last updated
Nov 28, 2022

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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