Transient femoral nerve palsy following ilio-inguinal nerve blockade for day case inguinal hernia repair.

BACKGROUND: Transient femoral nerve palsy (TFNP) has been reported in patients undergoing inguinal hernia repair involving the use of ilio-inguinal nerve block. Ilio-inguinal nerve blocks can be administered under vision by the surgeon or by the anaesthetist using a standard blind technique. There has been no study that has specifically examined the incidence of this complication and whether its development is related to the type of method used to administer the block.

PATIENTS AND METHODS: Data on patients undergoing surgery in the Royal Infirmary Edinburgh Day Case Unit are collected prospectively. All patients who undergo inguinal hernia repair are given ilio-inguinal field blocks, either pre-operatively by anaesthetists (blind technique) or peri-operatively under direct vision by surgeons. Several cases of TFNP were initially identified during the process of surgical audit and this led to a retrospective analysis over a period of one year.

RESULTS: During a 12-month period, 194 patients underwent 200 open inguinal hernia repairs (188 unilateral and 6 bilateral), under general anaesthesia. Ten patients (5%) developed TFNP resulting in overnight admission. Surgeons administered 101 blocks under direct vision of which 4 (4%) resulted in TFNP, whereas 6 out of 99 (6%) blind blocks resulted in TFNP (p=0.49, df=1, Chi2 test).

DISCUSSION AND CONCLUSION: TFNP is a recognised complication following ilioinguinal nerve blockade for inguinal hernia surgery. Our series shows that ilio-inguinal block given under direct vision does not appear to reduce the chance of this complication occurring. This may result from the fact that this complication could be due to local infiltration into the operative field rather than direct infiltration around the femoral nerve. As inguinal hernia repair undertaken as a day case procedure increases, the awareness of this complication is important to avoid morbidity