Chronic postsurgical inguinal pain: incidence and diagnostic biomarkers from a large German national claims database.

Abstract

Background: Chronic postsurgical inguinal pain (CPIP) is the most common complication of groin hernia surgery. The characteristics of patients, their medical care, and choice of diagnostic tools remain to be defined to optimise preventive and therapeutic interventions.

Methods: Claims data from 2018 and a 1-yr follow-up were analysed for incidence and medical care. A separate cohort (141 healthy controls and 17 CPIP patients) was examined by deep phenotyping. This included sensory testing, blood and skin biopsies, MRI of the dorsal root ganglion (DRG), and patient-reported outcomes.

Results: Of 11,221 patients with hernia surgery in 2018 identified, 8.5% had pain before that was relieved by surgery, but a similar percentage had novel pain in this region. Deep phenotyping of 141 healthy controls provided a map of the inguinal sensory system. The following analysis of patients with CPIP revealed that they suffered from moderate pain with neuropathic features, individual sensory abnormalities, and unilateral L1 DRG atrophy. In the blood, levels of C-C-motif chemokine ligand (CCL2) and brain-derived neurotrophic factor (BDNF) were upregulated, whereas apolipoprotein A1 (ApoA1) concentration was reduced. A cluster of DRG atrophy, BDNF, ApoA1, and anxiety correlated best with the diagnosis. CPIP patients with novel pain had significantly more DRG atrophy (-24% ipsilateral vs contralateral volume).

Conclusions: CPIP is often newly acquired after surgery. A combination of DRG imaging, serum markers, and anxiety screening can support the diagnosis. In the future, this could guide clinicians towards more personalised therapies (e.g. targeting anxiety or lipid profiles) and possible altered surgical techniques.

Clinical trial registration: German Trial Registry DRKS00024588 and DRKS00016790.