A 14-year-old boy presents with right knee pain and swelling. Workup reveals a high-grade osteosarcoma in the right proximal tibia without metastasis. After 10 weeks of treatment with methotrexate, doxorubicin, and cisplatin, he now presents for wide resection of the proximal tibia and knee reconstruction. Laboratory findings are: white blood cells 3; hemoglobin 8; hematocrit 24; platelets 130. Chest x-ray, electrocardiogram, and echocardiogram are normal.
A careful history and physical examination are important, and special attention should be paid to preoperative pain level and neurologic exam. In anticipation of blood loss, a type and screen, complete blood cell count, and possibly coagulation studies should be obtained. Preoperative embolization may be considered for highly vascular tumors.
Adjuvant chemotherapy is commonly used to treat patients with osteosarcoma, and each agent’s systemic effects must be evaluated. Doxorubicin (Adriamycin) is an anthracycline antibiotic that can lead to myelo-suppression (anemia, thrombocytopenia, neutropenia), and cardiomyopathy (arrhythmias, heart failure). Cisplatin is a DNA-altering drug that can lead to myelosuppression, nephrotoxicity, nausea/vomiting, peripheral neuropathy, and syndrome of inappropriate diuretic hormone. Methotrexate is an antimetabolite that can lead to myelosuppression, mucositis, diarrhea, pulmonary toxicity, and neurotoxicity at high doses.
A permanent central line used for chemotherapy may be available for induction. Sterile technique should be applied when accessing the line.
Tumors are usually very vascular, and blood loss can be significant. Obtain adequate IV access, including either two large peripheral IVs or one IV and a central line. An arterial line should be placed to check serial hematocrits.
Consider placement of a lumbar epidural or peripheral nerve block for intraoperative and postoperative pain management. Loading an epidural during the case will cause a sympathectomy and may lead to intraoperative hypotension. Typically a minimal platelet count of 100 × 109/L is required for neuroaxial techniques.
Positioning: Ensure padding of the operating room table and all extremities. If the patient is in lateral decubitus position, an axillary roll is necessary to prevent nerve injury and decreased blood flow to the dependent arm. Perfusion to the dependent arm should be monitored periodically. Check dependent eyes and ears for pressure.
Have blood products available. Cell saver cannot be used because of potential tumor spread.
Bone cement implantation syndrome may cause acute hypoxia and hypotension around the time of cementing, prosthesis insertion, or tourniquet deflation. Etiologies include a combination of the following: reaction to methyl methacrylate monomers, emboli of medullary bone contents under pressure from cement expansion, histamine release, and complement activation. Treatment is supportive.
Postoperative intubation and intensive care unit monitoring may be necessary for the first 24-48 hours. Possible strategies for pain management (including epidural; peripheral nerve blocks; IV patient-controlled analgesia; and use of adjuvant agents such as ketamine, gabapentin, nonsteroidal anti-inflammatory drugs, and methadone) should be ...