Evaluating the manubrium sterni as a site for bone implantation: a 3D radiological feasibility study

Background: To increase the number of patients who can speak hands-free after total laryngectomy, we aim to assess the viability of the manubrium sternibone (MSB) for bone implantation. Materials and methods: This retrospective cross-sectional study was conducted at the Department of Head and Neck Surgery of the Netherlands Cancer Institute in Amsterdam, the Netherlands, after approval by its Institutional Review Board. We included CT scans of 25 males and 24 females aged 53 to 88 years, and measured MSB morphometry and density, soft tissue thickness (STT), and bone surface slope, and classified the MSB. Heat maps were created to identify potential implant locations. Results: Median MSB height was 50.7 [95% confidence interval 49.4–53.4] mm, and mean thickness ranged from 8.7 [8.3–9.2] to 13.1 [12.7–13.6] mm. Mean width ranged from 53.2 [51.1–55.4] to 57.1 [55.3–59.1] mm. Significantly greater values of thickness and width were found in males. Body height had a significant positive effect on thickness and width measured at the thickest level. Median STT was 14.4 [12.7–17.4] mm, on which BMI had a significant positive effect. The trapezoid was the most common shape. Mean densities were 325 and 60 HU for cortical and cancellous bone, respectively, and cancellous density was significantly higher in males. As such, the MSB is most similar to the posterior maxilla with regard to implantation. Conclusion: In theory, the MSB is able to support a combination of three to four 6-mm implants, or of one 6-mm to 8-mm and two 10-mm implants, placed in a linear, triangular or diamond-shaped arrangement. Relevance statement: This study addresses knowledge gaps regarding the possibility of fixation methods of hands-free speaking valves offering greater stability than conventional methods. Radiological assessment of CT scans of the manubrium sternibone demonstrates its potential as an implantation site, although a thorough preimplantation workup of individual anatomy is imperative. Key Points: This is the first study that analyzes the manubrium sternibone three-dimensionally and assesses its potential as a bone implantation site. We found that it has low cortical and cancellous bone density, which makes it most similar to the posterior maxilla. The Manubrium sterni bone is suitable for implantation, although a preimplantation assessment of individual anatomy is imperative.