A preliminary safety assessment of vertebral augmentation with32P brachytherapy bone cement.

Comprehensive treatment for vertebral metastatic lesions commonly involves vertebral augmentation (vertebroplasty or kyphoplasty) to relieve pain and stabilize the spine followed by multiple sessions of radiotherapy. We propose to combine vertebral augmentation and radiotherapy into a single treatment by adding32P, aß-emitting radionuclide, to bone cement, thereby enabling spinal brachytherapy to be performed without irradiating the spinal cord. The goal of this study was to address key dosimetry and safety questions prior to performing extensive animal studies. The32P was in the form of hydroxyapatite powder activated by neutron bombardment in a nuclear reactor. We performedex vivodosimetry experiments to establish criteria for safe placement of the cement within the sheep vertebral body. In anin vivostudy, we treated three control ewes and three experimental ewes with brachytherapy cement containing 2.23-3.03 mCi32P ml-1to identify the preferred surgical approach, to determine if32P leaches from the cement and into the blood, urine, or feces, and to identify unexpected adverse effects. Ourex vivoexperiments showed that cement with 4 mCi32P ml-1could be safely implanted in the vertebral body if the cement surface is at least 4 mm from the spinal cord in sheep and 5 mm from the spinal cord in humans.In vivo, a lateral retroperitoneal surgical approach, ventral to the transverse processes, was identified as easy to perform while allowing a safe distance to the spinal cord. The blood, urine, and feces of the sheep did not contain detectable levels of32P, and the sheep did not experience any neurologic or other adverse effects from the brachytherapy cement. These results demonstrate, on a preliminary level, the relative safety of this brachytherapy cement and support additional development and testing.

Comparison of Area Deprivation Index, Socioeconomic Parameters, and Preoperative Demographics With Postoperative Emergency Department Visits After Total Knee Arthroplasty.

BACKGROUND: This study aims to determine if socioeconomic (SE) parameters, primarily area deprivation index (ADI), relate to postoperative emergency department (ED) visits after total knee arthroplasty (TKA). METHODS: We retrospectively reviewed 2655 patients who underwent TKA in a health system of 4 hospitals. The primary outcome was an ED visit within 90 days, which was divided into those with and without readmission. SE parameters including ADI as well as preoperative demographics were analyzed. Univariable and multiple logistic regressions were performed determining risk of 90-day postoperative ED visits, as well as once in the ED, risks for readmission. RESULTS: 436 patients (16.4%) presented to the ED within 90 days. ADI was not a risk factor. The multiple logistic regression demonstrated men, Medicare or Medicaid, and preoperative ED visits were consistently risk factors for a postoperative ED visit with and without readmission. Preoperative anticoagulation was only a risk factor for ED visits with readmission. Among patients who visited the ED, if the patient was Caucasian, a lower BMI, or higher American Society of Anesthesiologists score, they were likely to be readmitted. CONCLUSION: The study demonstrated that the percentage of early ED returns after TKA was high and that ADI was not a predictor for 90-day postoperative ED visit. The only SE factor that may contribute to this phenomenon was insurance type. Once in the ED, race, preoperative ED visits, preoperative anticoagulation, BMI, gender, and preoperative American Society of Anesthesiologists score contributed to a risk of readmission. The study supports hospitals' mission to provide equal access health care.

Complications of anterior cervical discectomy and fusion using recombinant human bone morphogenetic protein-2.

The use of bone morphogenetic protein-2 (rhBMP-2) in spinal fusion has increased dramatically since an FDA approval for its use in anterior lumbar fusion with the LT cage. There are several reports of its use in transforaminal lumbar interbody fusion, posterolateral fusion, and anterior cervical fusion. Reports on adverse effects of rhBMP-2 when used in spinal fusion are scarce in literature. An Institutional Review Board approved retrospective study was conducted in patients undergoing anterior spinal fusion and instrumentation following diskectomy at a single center. Forty-six consecutive patients were included. Twenty-two patients treated with rhBMP-2 and PEEK cages were compared to 24 in whom allograft spacers and demineralized bone matrix was used. Patients filled out Cervical Oswestry Scores, VAS for arm pain, neck pain, and had radiographs preoperatively as well at every follow up visit. Radiographic examination following surgery revealed end plate resorption in all patients in whom rhBMP-2 was used. This was followed by a period of new bone formation commencing at 6 weeks. In contrast, allograft patients showed a progressive blurring of end plate-allograft junction. Dysphagia was a common complication and it was significantly more frequent and more severe in patients in whom rhBMP-2 was used. Post operative swelling anterior to the vertebral body on lateral cervical spine X-ray was significantly larger in the rhBMP-2 group when measured from 1 to 6 weeks after which it was similar. These effects are possibly due to an early inflammatory response to rhBMP-2 and were observed to be dose related. With the parameters we used, there was no significant difference in the clinical outcome of patients in the two groups at 2 years. The cost of implants in patients treated with rhBMP-2 and PEEK spacers was more than three times the cost of allograft spacers and demineralized bone matrix in 1, 2, and 3-level cases. Despite providing consistently good fusion rates, we have abandoned using rhBMP-2 and PEEK cages for anterior cervical fusion, due to the side effects, high cost, and the availability of a suitable alternative.