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. 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.Introduction
Methods
Tumour volume reduction (i.e. response), assessed following induction chemotherapy, has been identified as a prognostic factor for localized embryonal rhabdomyosarcoma (RME) in the CWS studies. In combination with other risk factors, it has been used to stratify secondary local and systemic treatment. It is however unclear whether the poor outcome of non-responders is due to insufficient local and/or systemic post-induction treatment. We analyzed post-induction therapy of RME-patients <
21 years with unresected localized tumours (IRS-III) and poor response (NR, i.e. <
33% tumour volume reduction) treated 1980–2005 in five consecutive CWS-trials. The NR were reviewed and subclassified (Objective Response (OR; i.e.<
33%–0%) vs. Stable Disease/Progression (PD; i.e. no reduction)). From 758 IRS-III RME-patients, 59 were NR (n=34 OR, n=25 PD). Induction for NR included dactinomycin, vincristine, alkylators ± anthracyclines in all patients. There were no significant differences in comparison of the control group and NR with regard to age, size, TN-classification, apart from site (p=0.04), and no differences regarding these parameters between OR and PD. Twenty-four NR received continued induction chemotherapy, n=32 other combinations, and n=3 no further chemotherapy following response assessment. Four patients were treated with additional high-dose chemotherapy. Fourty-two NR were irradiated with a median dose of 48Gy (control group: 45Gy). In 20 NR, the tumours were completely resected. As of 9/2008, with a median follow-up of 4.5 years (range: 0.9–12.1) for NR survivors, 34 NR are alive in CR. Reasons for the 25 deaths were: local/combined failure (n=21), systemic failure (n=1), and other reasons (n= 3). 5-yrs-OS was 71±4% for the control group, 78±15% for OR, but only 43±15% for PD (p<
0.01). Response is an important surrogate marker of outcome, but per se associated with a poor prognosis only in tumours without any volume regression to induction chemotherapy. Ineffective local control drives mortality in these patients.
