Instrument separation in the apical region, particularly when the fragment extends beyond the apical foramen, often presents significant clinical challenges. Conventional retrieval techniques typically require excessive removal of radicular dentin, which may not only lead to complications such as root perforation or fracture, but also compromise the long-term prognosis of the affected tooth. However, for cases occurring during the final stages of high-quality root canal treatment, retaining the separated instrument may represent a more rational clinical approach when strict indications are met. This article reports a tooth with preoperative periapical pathology that experienced instrument separation extending beyond the apical foramen during treatment. Following comprehensive evaluation, a retention protocol was adopted. Nine years of follow-up observations confirmed the tooth's maintained functional integrity, validating the clinical efficacy and long-term sustainability of this management approach.