Model Limitations

Hybridization was treated as diversity loss, although in nature it can also increase diversity or promote reproductive barriers. The paper provides no empirical validation, statistical estimation, or numerical population data. The GNM cannot represent disease-specific mechanisms, organs, immune responses, or sequelae. The 1-year time horizon does not capture long-term survival differences, cumulative re-implantation complications, or delayed relapse costs from retained lead material. Survival data were limited to five years, so transition probabilities beyond five years required extrapolation. The model represents unspecified human tissue rather than a specific cell type. The model assumes extraction and re-implantation do not create future complications or costs beyond 1 year. The target population was 65 years old, but source studies did not always begin exactly at age 65. The paper uses numerical illustrations rather than empirical parameter fitting. The model's predictions are conditional on the chosen population-level birth intensity and mortality model. External validation was difficult because real-world studies lacked granular baseline data and had unclear detection-rate d…