Trepanation as a Plausible Early Form of Cranial Decompression

Trepanation is widely recognized as the earliest known cranial operation, yet its functional purpose remains debated. Traditional interpretations have emphasized ritual practice, treatment of cranial trauma, or empirical responses to neurological symptoms. We propose a focused historical-neurosurgical interpretation: that a meaningful subset of prehistoric trepanations may represent a plausible early empirical form of cranial decompression. The strongest quantitative evidence comes from the Cusco-region Peruvian series, in which 66 trepanned individuals accounted for 109 perforations and 26 individuals (39%) had multiple openings, suggesting that repeated cranial intervention was epidemiologically meaningful rather than anecdotal. Additional reports from ancient Greece, Late Iron Age Switzerland, Neolithic France, and Chalcolithic Spain provide convergent, though methodologically heterogeneous, evidence of repeated or multiple cranial intervention across independent populations. Canary Islands material independently supports the broader plausibility of intentional cranial procedures compatible with survival, while recent Guanche findings suggest that prehispanic cranial surgery may have included more than one form of intervention. Although ancient practitioners lacked a formal concept of intracranial pressure, the combined evidence of survival, repeated intervention, technical refinement, and trauma association supports the view that, in at least some cases, trepanation functioned as a pragmatic pressure-relieving cranial procedure and may represent an early empirical antecedent in the long historical arc of cranial decompression.