Another "Tool in the Toolbox" to Treat Metastatic Bone Disease of the Acetabulum and Pelvis: Commentary on an article by D. Ian English, MD, MA, et al.: "Minimally Invasive Stabilization with or without Ablation for Metastatic Periacetabular Tumors".

Abstract

Commentary Metastatic bone disease (MBD) is increasingly common because of the efficacy of new systemic drugs that can prolong life in patients with advanced cancers such as metastatic breast, lung, kidney, and prostate cancer as well as multiple myeloma1,2. One of the most common and challenging anatomical locations in which to treat MBD is the periacetabular region because of the resulting debilitating pain and risk of fractures leading to pelvic discontinuity. The decision to proceed with surgical intervention must be weighed against the surgical risks and perioperative morbidity associated with large reconstructive procedures in a complex patient population in which metastatic disease in the viscera and/or other skeletal locations may complicate surgical outcomes. The surgical approach to MBD of the acetabulum is tailored to the associated anatomical defects. For extensive defects extending across the anterior and posterior columns, modified Harrington reconstruction with intraosseous Steinmann pins and cementation (the rebar technique) combined with hip arthroplasty is an established procedure with acceptable and durable results, albeit with surgical morbidity-related extensive blood loss and large surgical wounds3,4. Acetabular lesions without pelvic discontinuity can be treated with complex hip reconstruction options involving cup-cage constructs and large cemented cups5. Finally, contained defects and smaller lesions can be managed with minimally invasive cementoplasty6-8. An evolving approach involves the combination of the rebar technique and cementoplasty in which percutaneous screw augmentation is combined with cement injection9. This approach allows for reduced surgical morbidity while providing greater structural support as compared with cementoplasty alone. English et al. reported on a single-center case series of 38 patients with periacetabular MBD that was treated with cementoplasty and screw augmentation with or without tumor tissue ablation. The patients in that series experienced pain palliation, restoration of function, and decreased narcotic use. The hospital stays were short for the majority of patients, with some patients being discharged to home on the same day as the procedure. There were no perioperative infections or wound complications and no delays in radiation or chemotherapy regimens. The authors reported a 16% reintervention rate related to disease progression or subchondral collapse. Conversion to total hip arthroplasty, when indicated, was uncomplicated. It is clear from this newly published series that augmented cementoplasty has several advantages, including the minimization of surgical morbidity, shorter hospital stays, and subsequent lower health-care costs. The authors showed that even in some patients with extensive bilateral disease, pain relief and improved function can be achieved with use of this minimally invasive technique. However, disease control also should be considered. Without open extensive tumor curettage, gross disease persists. Even with ablation and cementation, recurrent disease is a considerable risk. Only about 40% of patients in the series were alive at the time of the latest follow-up, complicating the issue of competing risks; that is, how many more patients would have developed local disease progression if they had not died10? Postoperative radiation therapy and systemic management can mitigate these risks, and therefore augmented cementoplasty may be most appropriate for patients with disease that is radioresponsive and chemoresponsive, in whom the risk of local disease progression is lowest. As cancer treatment continues to improve and patients with advanced disease survive longer with their disease, increasing numbers of patients will present to the orthopaedic surgical community with MBD in the periacetabular region. Therefore, the need for a wide range of effective surgical options tailored to individual patient needs becomes paramount. With the evolution of new techniques such as percutaneous augmented cementoplasty, the spectrum of surgical options is expanding. Although many patients may continue to benefit from open reconstructive procedures, others may be ideal candidates for less-invasive techniques. The risks and benefits of each of these approaches must be considered in the context of individual patient comorbidities, the anatomy of the associated acetabular defects, the overall oncological prognosis, and the biology of the underlying disease.