Abstract and Introduction
Introduction
Recalcitrant infections of bone and soft tissue compose an entity that is likely to be encountered by general orthopaedic surgeons and specialists alike. Treatment strategies may vary but often include some combination of long-term antibiotic administration for suppression or surgical debridement to obtain local source control.[1] Inspired by an unexpected finding in the operating room, Dahners and Bos[2] became the first authors to describe the concept of fluorescence-guided resections of osteomyelitis in 2002. In their study, the authors preoperatively administered tetracycline to patients and subsequently achieved an intraoperative view of viable versus dead (nonviable) bone by eliciting fluorescence with a Wood’s lamp.
Since the time of this ground-breaking introduction to fluorescence-guided resections, modern science has afforded clinicians with a better understanding of the mechanism of bone fluorescence. It is now known that a component of fluorescence is achieved via the chelation of tetracycline molecules within the inorganic mineral matrix of bone.[3,4] Additionally, a second facet exists in which natural fluorescence is exhibited in the absence of tetracyclines due to fluorophores (tryptophan, tyrosine, phenylalanine) contained within collagen.[5,6] Moreover, a Wood’s lamp or a generic blacklight is capable of serving as an appropriate excitation source for both the tetracycline and the collagen components contributing to the overall fluorescence.[7]
Whether an orthopaedic surgeon who is treating chronic osteomyelitis or a maxillofacial surgeon who is treating osteonecrosis of the jaw, from whom most of the fluorescence-guided resection literature has developed, one of the common themes is adequate resection of nonviable infected bone. However, the literature and personal experience of the senior author suggest that identifying living, viable bone can be challenging. Debridement to bleeding bone, despite being an easy and often-utilized method to assess bone viability, may not correlate with a bone’s metabolic state as judged by its fluorescent intensity.[8–10] However, the quantity of healthy osteocytes in a sample has been demonstrated to correlate with visible fluorescence as well as osteomyelitis or necrosis.[11–13] Thus, green fluorescence (and occasionally other hues) can be used to demarcate viable bone. Fluorescence intensity has even been noted anecdotally to increase as nonviable bone is debrided.[8,14]
Given the compelling evidence for fluorescence-guided resection, the senior author has begun preoperatively to administer doxycycline to her patients prior to debridement of chronic osteomyelitis. The primary goal of this manuscript was to further describe this technique and revive a classic “trick” that has not been described in the orthopaedic literature since 2002. Informed consent was obtained from all patients before surgery. This technique description in a small case series was exempt from institutional review board approval.