Dermatome Mapping (Marking area of Groin Pain)
After taking detailed notes of the pain and its description with a subsequent clinical examination, dermatome mapping is then carried out to try as best as possible, to record the pain experienced in terms of its location, nature and severity. This is called dermatome mapping and is universally accepted by clinicians.
A reference point is used just next to the umbilicus ‘belly-button’ and using a ballpoint pen the area of pain experienced is mapped with this accepted classification system to best describe the pain, both before and after any treatment.
Symbols used to mark the area are:
X – Pain
O – No pain
- (Dash) – Insensate or Numbness (usually after nerve division as treatment)
The types of pain experienced can be either Neuropathic (sharp on contact) due to direct nerve damage and this usually presents early after surgery – it is easier to identify and eventually treat.
Non neuropathic pain or nociceptive is more like ‘discomfort’ and can be as a result of soft tissue damage, heat damage to structures at the time of surgery, mesh complications such as a meshoma or granuloma (hard scarred tissue formation) – this pain presents later, it is more difficult to pin-point & identify its actual cause and so is consequently harder to treat.
The ilioinguinal, iliohypogastric and genital branch of the genitofemoral nerves are more likely to be damaged in open hernia surgery.
The Lateral cutaneous nerves of the thigh, ilioinguinal (rarely) and femoral branch of the genitofemoral nerves are more likely to be damaged in laparoscopic (keyhole) surgery.
Please see Dermatome Mapping Classification of Groin Pain as devised by Drs R Alvarez and D Chen
VAS = Visual Analogue pain score is also used to calculate the severity of the pain experienced with the addition of a Verbal categorical rating scale
Campanelli et al Surgical treatment of chronic pain after inguinal hernia repair. Hernia (2013); 17(3): 347-53
Bjurstom et al Quantitative validation of sensory mapping in persistent postherniorrhaphy inguinal pain patients undergoing triple neurectomy Hernia DOI 10.1007/s10029-017-1580-4
Amid et al Surgical treatment of chronic groin pain and testicular pain after laparoscopic and open pre-peritoneal inguinal hernia repair J Am Coll Surg. 2001; 213(4): 531-6
Assen et al Surgical options after a failed neurectomy in anterior cutaneous nerve entrapment syndrome. World J Surg. 2014 Dec;38(12):3105-11