ABSTRACT
INTRODUCTION: Infection is a common mode of failure in lower extremity endoprostheses. The Prophylactic Antibiotic Regimens in Tumor Surgery trial reported that 5 days of cefazolin had no difference in surgical site infection compared with 24 hours of cefazolin. Our purpose was to evaluate infection rates of patients receiving perioperative cefazolin monotherapy, cefazolin-vancomycin dual therapy, or alternative antibiotic regimens. METHODS: A single-center retrospective review was conducted on patients who received lower extremity endoprostheses from 2008 to 2021 with minimum 1-year follow-up. Three prophylactic antibiotic regimen groups were compared: cefazolin monotherapy, cefazolin-vancomycin dual therapy, and alternative regimens. The primary outcome was deep infection, defined by a sinus tract, positive culture, or clinical diagnosis. Secondary outcomes were revision surgery, microorganisms isolated, and superficial wound issues. RESULTS: The overall deep infection rate was 10% (30/294) at the median final follow-up of 3.0 years (IQR 1.7 to 5.4). The deep infection rates in the cefazolin, cefazolin-vancomycin, and alternative regimen groups were 8% (6/72), 10% (18/179), and 14% (6/43), respectively (P = 0.625). Patients not receiving cefazolin had an 18% deep infection rate (6/34) and 21% revision surgery rate (7/34) compared with a 9% deep infection rate (24/260) (P = 0.13) and 12% revision surgery rate (31/260) (P = 0.17) in patients receiving cefazolin. In those not receiving cefazolin, 88% (30/34) were due to a documented penicillin allergy, only two being anaphylaxis. All six patients in the alternative regimen group who developed deep infections did not receive cefazolin secondary to nonanaphylactic penicillin allergy. CONCLUSION: The addition of perioperative vancomycin to cefazolin in lower extremity endoprosthetic reconstructions was not associated with a lower deep infection rate. Patients who did not receive cefazolin trended toward higher rates of deep infection and revision surgery, although not statistically significant. The most common reason for not receiving cefazolin was a nonanaphylactic penicillin allergy, highlighting the continued practice of foregoing cefazolin unnecessarily.
ABSTRACT
Background: Metabolic bone diseases (MBD) are typically diagnosed by non-invasive imaging and clinical biomarkers. However, imaging does not provide structural information, and biomarkers can be transiently affected by many systemic factors. Bone biopsy and pathologic evaluation is the gold standard for diagnosis of MBD, however, it is rarely utilized. We describe our technique for iliac crest tetracycline-labelled bone using a cannulated drill and assess the utility of bone biopsies to provide diagnostic and therapeutic guidance. Methods: In the 25-year period between March 1998 and January 2023, a total of 95 bone biopsies were performed on 94 patients for an osteological indication at Vanderbilt University Medical Center (VUMC). Patient demographics, bone biopsy indications, complications, diagnostic utility, and subsequent therapeutic guidance were retrospectively reviewed and analyzed. Results: The procedure had minimal complications and was well tolerated by patients. This technique provided good quality specimens for pathology, which helped establish a diagnosis and treatment change in most patients. Patients that had biopsy-guided treatment alterations showed significant increases in Dual-Energy X-ray Absorptiometry (DEXA) bone mineral density (BMD) scores post-biopsy and subsequent treatment. Conclusion: Despite scientific and technological progress in non-invasive diagnostic imaging, clinical biomarkers, and procedures for MBD, there remains a small but significant subset of patients who may benefit from inclusion of tetracycline-labelled bone biopsy into the diagnostic and therapeutic picture. Future prospective comparison studies are warranted. Mini abstract: Tetracycline-labelled bone biopsies are under-utilized. Biopsy led to a histological diagnosis and ensuing treatment alteration in most patients with significant increases in bone mineral density. The biopsy procedure used herein provided good specimens with low pain/adverse events. Bone biopsy remains a valuable tool in a small, though significant, subset of patients.
ABSTRACT
A 74-year-old man with a medical history significant for papillary thyroid cancer (PTC) presented with a rapidly enlarging grape-sized mass in his right medial arm with paresthesia in the ulnar nerve distribution. Imaging was suspicious for a peripheral nerve sheath tumor (PNST), but an ultrasound-guided biopsy was equivocal. The mass was excised with final histopathology demonstrating a benign neurofibroma/schwannoma hybrid nerve sheath tumor (N/S HNST) harboring a metastatic PTC deposit, ultimately mimicking the rare glandular schwannoma subtype. Next-generation sequencing (NGS) of the lesion demonstrated somatic variants in BRAF and TERT (common in PTC) and NF2 (common in PNSTs). After excision, the patient's nerve symptoms improved. A postsurgical PET/CT scan also showed progression in the lungs/mediastinum. Due to the metastatic nature of his PTC, he was treated with 14 mg of Lenvima (lenvatinib) daily, and his PET/CT surveillance was performed at more frequent intervals. Tumor-to-tumor metastasis (TTM) is a rare occurrence. To our knowledge, this is the first case reported on PTC metastasizing into a benign (hybrid) PNST, which mimicked glandular schwannoma. Symptomatology, imaging characteristics, NGS, and histopathological characteristics that can decipher between different benign PNST subtypes (schwannoma, neurofibroma, glandular, hybrid, etc.), malignant PNSTs (MPNSTs), and TTM are described.