Abstract
Introduction
The rate of total hip arthroplasty (THA) surgery continues to dramatically rise in the United States, with over 300,000 procedures performed in 2010. Although a relatively safe procedure, THA is not without complications. These complications include acetabular fracture, heterotopic ossification, implant failure, and nerve palsy to name a few. The rates of neurologic injury for a primary THA are reported as 0.7–3.5%. These rates increase to 7.6% for revision THA. The direct anterior total hip arthroplasty (DATHA) is gaining popularity amongst orthopedic surgeons. Many of these surgeons elect to use the Hana® table during this procedure for optimal positioning capability. Although intraoperative mobility and positioning of the hip joint during DATHA improves operative access, select positions of the limb put certain neurologic structures at risk. The most commonly reported neurologic injuries in this regard are to the sciatic and femoral nerves. To our knowledge, the use of neuromonitoring during DATHA, especially those using the Hana® table, has not been described in the literature.
Methods
The patient was a 60-year-old male with long standing osteoarthritis of the right hip and prior left THA. Somatosensory evoked potential (SSEP) leads were placed bilaterally into the hand (ulnar nerve) as well as the popliteal fossae (posterior tibial nerve). Unilateral electromyography leads were placed into the vastus medialis obliquus, biceps femoris, gastrocnemius, tibialis anterior, and abductor hallucis of the operative limb (Fig. 1). Once the patient was sterilely draped, a direct anterior Smith-Peterson approach to the hip was used.
Results
After the patient completed standard pre-operative protocol, neuromonitoring leads were placed as described above. There were no complications, neuromonitoring remained stable from baseline, and the patient tolerated the procedure well. Moreover, the senior author routinely uses a prophylactic cable around the calcar, particularly in patients with osteoporotic bone, as was the case with this patient. The patient's post-operative course has been without complications as well.
Conclusion
There are a few studies that have examined the pressure changes around the femoral nerve during a DATHA and found that the nerve was at most danger with misplacement of a retractor near the anterior lip of the acetabulum. Furthermore, the popularity of DATHA and the Hana® table make neuromonitoring more amenable for use since the whole limb does not need to be sterilely prepped as with other approaches to the hip. The reported rates of neurologic injury during any THA along with those developed from passage of prophylactic cerclage cables and the goals of reducing surgical complications make this novel technique intriguing. It allows the surgeon yet another safe and effective tool to decrease the likelihood of neurologic injury during DATHA.
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