Surgical management of chronic inguinal pain syndromes - Liespijn

INTRODUCTIONWorldwide millions of low transverse Pfannenstiel incisions are performed each year inobstetric and gynaecological practice. Ever since its introduction this approach has beena successful access path for lower abdominal surgery with an exceptionally low incisionalhernia rate (0-2%) and an aesthetically pleasing appearance (‘bikini cut’) 1,2 . Moreover,Pfannenstiel incisions are frequently used in laparoscopic procedures for removal ofresected specimens 3,4 .The Pfannenstiel technique harbours one serious drawback being ‘nerve entrapment’ 2 .According to recent reports chronic pain is more commonly observed than previouslythought (12.3% - 33%) 2,5-8 . One study with a two year follow up reported that 8% ofpatients with a Pfannenstiel incision graded their pain as moderate or severe leadingFigure 1 Cutaneous innervation of lower abdomen 21 .This figure has appeared in the article by Ducic et al. Algorithm for treatment of postoperativeincisional groin pain after cesarean delivery or hysterectomy. Obstet Gynecol 2006; 108: 27-31.to limitations in daily functioning 5 . As laparoscopy with concomitant Pfannenstielincision is gaining popularity in general surgery, the incidence of nerve entrapmentswill probably rise as well.Treatment consists of nerve blocks or neurectomy. Aim of the present study was toassess long-term pain relief following these treatment modalities in patients sufferingfrom chronic pain due to Pfannenstiel-induced nerve entrapment.Anatomy and pathophysiology 5The cutaneous innervation of the lower abdomen is mainly supplied by two nerves, theiliohypogastric and the ilioinguinal nerves (figure 1). Originating from 12th thoracic and1st lumbar roots, they run on the anterior aspect of the lumbar quadrate muscle andpenetrate the transverse and internal oblique muscles. Endings of these nerves can befound subcutaneously or subfascially at the lateral margin of the abdominal rectusmuscles. If dissection during a Pfannenstiel incision is executed too laterally, thesenerves may be harmed potentially creating a neuroma 2 . Moreover, nerves may be traumatizeddue to perioperative retraction or following constricting sutures. Developmentof fibrotic tissues later on can also initiate nerve entrapment. Considerable anatomicvariability and overlapping cutaneous innervation areas complicate localisation andidentification of affected nerves and render clinical discrimination of iliohypogastricand ilioinguinal nerves exceedingly difficult 9,10 . In women the genitofemoral nerveaccompanies the round ligament and is nearly always unaffected during Pfannenstielsurgery. A neurectomy of the genital branch is therefore unnecessary. However concurrentipsilateral inguinal hernioplasty mandates a triple neurectomy according to Amid.Clinical presentation and diagnostic work-upPain may be reported immediately postoperatively or may develop over time. Neuropathicpain initiated by entrapped or damaged nerve tissue is characterized bylancinating, sharp or stabbing pain sensations at the incisional corners irradiating topubic area and/or upper leg. Hyperextension or twisting upper body movements caninduce pain by means of nerve traction or compression. Menstruation may increasepain sensations due to hormone-induced neurotransmitters. However, cutaneousendometriosis should also be considered 11 .At physical examination neurophysiological disorders such as hypoesthesia, hyperesthesiaor allodynia are often present. Remarkably, patients may not be aware of theseneurological abnormalities. Pressuring the incisional edge(s) at the abdominal rectusmargin may reveal a distinct trigger point. If active abdominal muscle contractionintensifies pain (positive Carnett’s sign), the pain is probably located in the abdominalwall. If nerve entrapment is likely, the diagnostic work-up should include a nerve blockusing a short-acting anaesthetic (e.g. lidocain) placed into the trigger point. Suchinjections ideally provide immediate pain relief and contribute to the diagnosis 5 .110 Chapter 8Surgical management of inguinal neuralgia after a low transverse Pfannenstiel incision 111