Orthopaedic Oncology Research
List of Projects & Funding
Clinical research aimed at the aforementioned bone and soft tissue tumors and tumor-like conditions is conducted in a collaborative fashion between Dr. O’Donnell and professional colleagues at UCSF and throughout the world. Examples of projects devoted to improving the care of patients with these diverse diagnoses include:
Compressive osseointegration technology: A principal research effort is directed toward the study of a novel means of fixation for endoprosthetic devices needed to reconstruct skeletal defects in cases of tumor resection and failed arthroplasty. Traditional usage of long intramedullary stems and cement has been associated with stress shielding, osteolysis, and ultimate failure. Compressive osseointegration technology achieves immediate, rigid fixation and subsequent bone hypertrophy that develops in response to compression forces. This result enhances the success and longevity of limb salvage procedures, especially in young, active individuals.
Immediate post-operative prosthetic fitting: When limb salvage is not possible, patients facing an amputation are routinely treated with immediate post-operative prostheses (IPOPs). Applied in the operating room by expert UCSF Prosthetists, these external devices are custom-fit to the patient’s residual limb. IPOPs help to mold and shape the leg, decrease pain and swelling, and allow weight bearing on the first day after surgery. Ultimately, standard prosthetic fitting is also accomplished much sooner.
Adjuvants and bone graft substitutes: A variety of adjuvant measures are available at UCSF for intralesional management of benign bone lesions, including cryotherapy and argon beam coagulation. Packing is performed with bone cement or coralline hydroxyapatite, so as to minimize complications associated with traditional grafts.
CT-guided percutaneous radiofrequency thermal ablation: Osteoid osteoma patients are treated in collaboration with the UCSF Department of Radiology with CT-guided percutaneous radiofrequency thermal ablation. This minimally invasive outpatient procedure is highly successful in precisely localizing and eliminating the painful osteoid osteoma nidus, so that surgery is generally no longer necessary. CT-guided ablation is also used for management of selected small metastatic deposits in bone, and CT-guided techniques are applicable for diagnostic biopsy of bone lesions.
Multidisciplinary management of soft tissue sarcomas: Another intensive area of investigation is the use of pre-operative chemotherapy as part of a multidisciplinary treatment program for soft tissue sarcoma patients. Arising at a rate of just twenty new cases per year per million people, soft tissue sarcomas remain one the rarest forms of cancer. Fortunately, advances in radiologic imaging, surgery, radiation therapy, and chemotherapy have served to improve local control and overall survival. Wide surgical resection and external beam radiation therapy remain the mainstays of treatment. For patients younger than 65 years of age with large, deep, high grade tumors, pre-operative chemotherapy is also being offered in an attempt not only to treat the tumor itself, but also to decrease the risk of metastatic disease, thereby increasing overall survival.
Intraoperative radiation therapy: The UCSF Orthopaedic Oncology Service is very fortunate to have access to state-of the-art intraoperative external beam radiation therapy machines which are used to apply radiation when and where it is needed most— directly to the soft tissue sarcoma tumor bed at the time of surgery. Close collaboration with the UCSF Radiation Oncology Staff has resulted in extensive experience with this technique that allows precise delivery of radiation, thus minimizing the extent of exposure and, it is hoped, improving function and the local control rate for these aggressive tumors.