Surgical management of chronic inguinal pain syndromes - Liespijn

INTRODUCTIONImplantation of mesh is considered the ‘gold standard’ for the treatment of inguinalhernia repair as the risk of recurrence is half compared to traditional non-mesh techniques1 . Ever since recurrence rates declined, attention has gradually shifted towardsstudying the onset of chronic pain following inguinal mesh repair as an early studyreported a staggering 63% incidence rate of chronic postoperative pain 2 . From the midninetieson somewhat lower (0-53%) incidence rates of chronic pain were published 3-5 .However, the need for additional research on etiology and treatment of these chronicpain syndromes following inguinal mesh repair became increasingly evident.Non-mesh inguinal procedures including Pfannenstiel incisions that are frequently usedas an aid in laparoscopic or gynaecological surgery are also noted to coincide with painsymptoms that appeared similar as observed following mesh inguinal hernia repair 6,7 .Interestingly, efforts that systematically studied incidence rate and risk factors for chronicpain syndromes after a Pfannenstiel incision have not been performed.Chronic pain after mesh implantation for inguinal hernia repair or after a Pfannenstielapproach is likely related to the interference with nerve structures located in the lowerabdominal and inguinal area. A thorough knowledge on the complex anatomy of theseregions aids in understanding the characteristics of these chronic inguinal pain syndromes.AnatomyDifferent myofascial layers compose the lower abdominal and the inguinal canal. Thesensory innervation of these areas is provided by four inguinal nerves, the iliohypogastric,ilioinguinal, genitofemoral and lateral femoral cutaneous nerve. The latter israrely affected due to its lateral position and is not discussed. In contrast, the other threenerves may be injured following surgical manipulation associated with inguinal herniarepair or Pfannenstiel incisions.The iliohypogastric nerve is the most cranial of the three. It arises from T12 / L1 vertebrae,runs ventrally from the lumbar quadrate muscle and gradually pierces various layers ofthe abdominal wall. Its function is to supply the suprapubic region with sensation. Theilioinguinal nerve originates from the same vertebral level and travels a similar coursea few centimetres caudal to the iliohypogastric nerve. Sensation to the base of the pubicarea and inner thigh is provided by this nerve. Endings of both these nerves can befound subcutaneously or subfascially at the lateral margin of the rectus border.The genitofemoral nerve originates from L1/ L2 and pierces the iliopsoas muscle whereit runs caudally on its ventral surface. It usually demonstrates a division into a genitaland femoral branch some centimetres proximal to the inguinal ligament. The genitalbranch subsequently runs underneath the spermatic cord or round ligament innervatingthe scrotum or labia majora. In men, the genital branch also forms the afferent8 Chapter 1Introduction, aims and outline 9