Intramedullary nailing (IMN) is one of the most common surgical operations for fixation of long bone fractures. Distal interlocking of intramedullary nails is a challenging procedure in orthopedic trauma surgery. One of the most difficult parts of the surgery is to find the accurate drilling position and direction to fasten the interlocking screw since the nail is placed inside the bone canal and the locations of its holes are invisible. Numerous techniques for distal interlocking screw insertion have been described aiming to decrease ionizing radiation exposure, number of drilling, and operation time. However, these techniques have not gained widespread clinical application and this process is doing either by fluoroscopy that called free-hand technique (FH) or by a special device designed for this purpose, known as targeting-arm devices (TAD). Fluoroscopy is a high-cost operation whereby patients and the surgical team are exposed to X-rays. The targeting device is a time-consuming process that involves trial and error. In such situations, the surgeon makes new guesses and drills repeatedly to find the position of the intramedullary nail holes which is very damaging to the tissue. The purpose of this study was to provide a more accurate and non-invasive method for orthopedic surgeons to easily determine the position of intramedullary nail holes in order to insert its screws. The proposed method is the application of a safe light to detect of the intramedullary nail holes. In addition to having the necessary safety features, this light must have desirable properties of transmittance, reflectance, and absorbance and be visible to the naked eye. For this purpose, Ex-Vivo and In-Vivo spectroscopy experiments were performed in the visible range of electromagnetic waves and the appropriate electromagnetic wavelength was determined. The laser intramedullary nail holes detector was designed and built according to ANSI Z136.3 – 2018 (American National Standard for Safe Use of Lasers in Health Care). Performance experiments were performed on animal samples. After receiving acceptable results, human tests were performed by orthopedic surgeons. Using laser intramedullary nail holes detector is a simple inexpensive method that reduces the surgical time and simplifies the process. This is an X-ray-free technique and prevents the patient and the surgical team from being exposed to X-rays. This new technology makes it easier to determine the position of intramedullary nail holes. This instrument paves the way for development of effective and safe intramedullary nailing in clinical applications. Keywords: Intramedullary Nail, Distal interlocking, Orthopedic, surgery, Laser
