Near infrared spectroscopy for the photodiagnosis of osteonecrosis, a future perspective. Mini historical review

Purpose: Osteonecrosis is a condition resulting from the death of bone tissue caused by the loss of vascularization, leading to the exposure of necrotic bone. Noninvasive optical techniques capable of evaluating the hemodynamic status of bone tissue as near infrared (NIR) spectroscopy have been studied for the diagnosis of osteonecrosis. This study aims to highlight studies in which NIR spectroscopy was used to evaluate bone characteristics, discussing its usefulness in the perfusion diagnosis of osteonecrosis. In this narrative review 16 PUBMED studies were selected, that provided initial evidence that the hemodynamic pattern of normal bone tissue identified by NIR spectroscopy is different from the NIR spectral pattern found in injured tissue. These studies suggest also that NIR spectroscopy has reproducibility and associations with other well-known imaging methodologies, indicating that NIR spectroscopy could become a potential technique for the perfusion diagnosis of osteonecrosis in real assessments of superficial bone surfaces. It may be advantageous in the early diagnosis of asymptomatic cases that lead to compromised microcirculation. Due to variability between the data available, a standard of normality has not yet been established, making comparisons between patients or the establishment of a cutoff value for the diagnosis of bone hypoperfusion states difficult.