Preoperative three-dimensional simulation and clinical evaluation of in-situ bone harvesting in anterior cervical discectomy and fusion surgery.

Background: The supplemental harvesting of in-situ bone obtained from cervical vertebrae as cage-filling material in anterior cervical discectomy and fusion (ACDF) results in a good fusion outcome. This study aimed to further quantitatively evaluate the obtainable bone volume and clinical outcomes of cervical in-situ autogenous bone grafting based on a three-dimensional (3D) preoperative simulation.

Methods: This study included 78 patients who underwent single-level ACDF. Prior to the surgical procedure, a 3D simulated surgery was performed by constructing several cutting planes in the cervical vertebrae based on Mimics software. The volumes of the harvested in-situ bone graft, including the anterior lip, posterior osteophytes, and Luschka's joint volumes, were measured during the simulated surgery. Immediate postoperative computed tomography (CT) scans were performed to evaluate the efficacy of the preoperative planning. During the postoperative follow-up period, the neurological function and cervical fusion state were also evaluated.

Results: The average volume of the cage's bone graft groove was 373.1±74.4 mm³, which was lower than that calculated in the preoperative planning (501.6±179.6 mm³, P<0.001). In 88.5% (69/78) of the simulated surgery cases, the harvested bone met the volume of the cage's bone graft groove, aligning with the intraoperative scenario. Male patients, elderly patients, patients with lower surgical segments, and patients with higher-grade facet joint degeneration had a more sufficient availability of in-situ autologous bone. The mean follow-up time was 18.02±4.9 months. At the final follow-up, the pain and functional status scores of the patients had improved significantly following surgery (P<0.05).

Conclusions: Preoperative planning for ACDF using Mimics software was shown to be both feasible and accurate. The 3D simulated surgery revealed that the majority of patients could supply a sufficient volume of cervical autologous bone for intraoperative grafting. The comprehensive analysis of the in-situ bone harvesting in ACDF provided precise reference data for the clinical implementation.