Dermatome Mapping Test in the analysis of anatomo-clinical correlations after inguinal hernia repair

Abstract

Background Nerve identification is recommended in inguinal hernia repair to reduce or avoid postoperative pain. The aim of this prospective observational study was to identify nerve prevalence and find a correlation between neuroanatomy and chronic neuropathic postoperative inguinal pain (CPIP) after 6 months. Material A total of 115 patients, who underwent inguinal hernia mesh repair (Lichtenstein tension-free mesh repair) between July 2018 and January 2019, were included in this prospective observational study. The mean age and BMI respectively resulted 64 years and 25.8 with minimal inverse distribution of BMI with respect to age. Most of the hernias were direct (59.1%) and of medium dimension (47.8%). Furthermore, these patients were undergoing Dermatome Mapping Test in preoperatively and postoperatively 6 months evaluation. Results Identification rates of the iliohypogastric (IH), ilioinguinal (II) and genitofemoral (GF) nerves were 72.2%, 82.6% and 48.7% respectively. In the analysis of nerve prevalence according to BMI, the IH was statistically significant higher in patients with BMI < 25 than BMI ≥ 25 P (< 0.05). After inguinal hernia mesh repair, 8 patients (6.9%) had chronic postoperative neuropathic inguinal pain after 6 months. The CPIP prevailed at II/GF dermatome. The relation between the identification/neurectomy of the II nerve and chronic postoperative inguinal pain after 6 months was not significant (P = 0.542). Conclusion The anatomy of inguinal nerve is very heterogeneous and for this reason an accurate knowledge of these variations is needed during the open mesh repair of inguinal hernias. The new results of our analysis is the statistically significant higher IH nerve prevalence in patients with BMI < 25; probably the identification of inguinal nerve is more complex in obese patients. In the chronic postoperative inguinal pain, the II nerve may have a predominant role in determining postoperative long-term symptoms. Dermatome Mapping Test in an easy and safe method for preoperative and postoperative 6 months evaluation of groin pain. The most important evidence of our analysis is that the prevalence of chronic pain is higher when the nerves were not identified.

Authors’ Reply: Ilioinguinal Nerve Neurectomy is better than Preservation in Lichtenstein Hernia Repair: A Systematic Literature Review and Meta‐analysis

“…The bias of this results is the lower number of studies included in these analyses (only half of the papers included reported data at 6 months and only one paper reported data at 12 months), as well as the heterogeneous evaluation of these data for the absence of a common standardized system. The improved use of Dermatome Mapping Test in common clinical practice can represent an adequate system for the standardization of future RCTs [66]. In the current torrent of data, cautions are needed for the lack of this additional crucial information about paresthesia and hypoesthesia.…”

“…In our analysis, we reported that the prophylactic IIN neurectomy seems to offer some advantages concerning postoperative inguinal pain in the first 6th month period, but this advantage is associated with the risk of hypoesthesia that it is higher in recent post‐operative analysis performed with Dermatome Mapping Test (14.8%) [4].…”

Nerve identification in open inguinal hernioplasty: A meta-analysis

“…lifting and twisting of the cord. The difficult identification of GB is well-reported in the surgical literature (18,19,21,22).…”

“…The sample range was 29 to 973, with a median of 144. A total of 2118 surgical dissections were reported on nerve identification (15)(16)(17)(18)(19)(20)(21)(22). The objectives of Lange 2009, Grossi 2015 and Mendes 2016 were centered on the intraoperative identification of the nerves only.…”

Comparison of the analgesic efficacy of the ultrasound-guided transversalis fascia plane block and erector spinae plane block in patients undergoing open inguinal hernia repair under spinal anesthesia

“…In OIHR surgery, the subcostal nerve (T12), ilioinguinal nerve (L1), iliohypogastric nerve (T12-L1), and sometimes the genitofemoral nerve (L1-L2) provide sensory innervation to the incision area [ 9 – 11 ]. According to the literature, II-IH and transversus abdominis plane (TAP) blocks are used most frequently to treat postoperative pain following OIHR surgery [ 12 ].…”