Intraoperative neurophysiological monitoring of somatosensory evoked potentials during hip arthroscopy surgery

Arthroscopic hip surgery is used to treat many of the causes of hip pain, hip instability, and hip disorders. Hip pain and instability are often caused by injuries to the acetabular labrum. Repairing labral tears, suturing, and debridement involve stabilizing the hip and placing the operative side leg in traction (Phillipon 2006, Phillipon and Schenker 2006) to allow for instrument clearance and to avoid iatrogenic injury to the chondral surfaces. This places the sciatic nerve in a stretched position and may cause temporary or permanent nerve injury. Transient neuropraxia is the most common injury occurring in 5% of the patients undergoing arthroscopic hip surgery (McCarthy and Lee 2006). 35 patients; 24 women and 11 men, (a total of 36 surgeries) were monitored with intraoperative neurophysiological monitoring using somatosensory evoked potentials (SSEPs) during hip arthroscopy for labral repair and femoral head osteoplasty. They ranged in age from 15 to 59 years; mean age: 39.81 years. During surgery 19 (54%) patients experienced significant SSEP waveform changes. Time from placement of traction to loss of signals in those patients experiencing SSEP changes ranged from 7 minutes to 46 minutes. Recovery of SSEP signals ranged from 2 minutes to over 15 minutes when the traction of the leg was released. Surgeries ranged from 2 to 4 hours; mean: 2.78 hours. These findings show that neuromonitoring during hip arthroscopic labral repair and debridement procedures might be useful to prevent temporary and permanent neural tissue injuries.