Access Consequences of Restricting Mohs Micrographic Surgery to Fellowship-Trained Surgeons: A National Workforce, Board-Certification, and Drive-Time Simulation Study

Background: Policies restricting Mohs micrographic surgery (MMS) to only fellowship-trained (FT) surgeons -- through privileging standards, laboratory-director qualifications, or payer credentialing -- would bar residency/practice-trained (R/P-trained) surgeons from MMS. The access consequences have not been quantified. Objective: To quantify the workforce, board-certification, geographic, and patient-access consequences of restricting MMS to only fellowship-trained surgeons. Methods: Cross-sectional analysis of all Medicare MMS billers (2020-2024; n=3,451), classified FT versus R/P-trained by complete ACMS directory linkage (the definition of prior national analyses; audited); linkage to American Board of Dermatology Micrographic Dermatologic Surgery (MDS) certification records; county/market access classes; road-network drive-time simulation of R/P-trained exclusion against CMS network-adequacy standards; fellowship-pipeline replacement modeling. Results: R/P-trained surgeons were 45.3% of the 2024 workforce, 55.6% held MDS certification, and they supplied 52.1% of nonmetropolitan MMS volume. In 223 counties (23.4 million residents) they were the only Mohs surgeons. Simulated exclusion pushed 15.6 million more people beyond 60 minutes' drive and 23.1 million out of CMS dermatology time-and-distance standards, disproportionately rural (3.2x). Pipeline replacement of rural capacity would require approximately 21 years. Absorbing the displaced volume (353,736 Medicare cases/year, 88% metropolitan) would require surviving surgeons to raise volume by 45.5%; even if every surviving surgeon took on 20% more cases, 211,848 cases/year would have no slot, and at 50% more, when national capacity would suffice, 94,982 would still remain beyond the reach of any surgeon with room because of the workforce's geographic distribution -- implying longer waits and stranded patients in metropolitan and rural areas alike. All findings were robust to the audited misclassification error of the training-pathway definition. Limitations: Medicare fee-for-service claims; directory-based training-pathway classification, audited and adjusted. Conclusion: A fellowship-only restriction -- for example, a fellowship-gated qualification for directing the laboratories in which Mohs frozen sections are examined -- would bar R/P-trained surgeons from directing the Mohs laboratories where they operate and would produce large, geographically concentrated access losses, borne disproportionately by rural America, without demonstrated quality benefit. Workforce policy should instead expand every route into Mohs surgery -- more fellowship positions, stronger Mohs training within dermatology residency, practice-based training that certifying boards and payers continue to recognize, and a reopened practice pathway to MDS certification -- while keeping regulatory eligibility keyed to primary dermatology board certification, which both pathways share.