Postoperative headache after decompressive Craniectomy and Cranioplasty: A prospective two-year cohort with topographic characterization of neuralgiform pain

Objective: Headache after decompressive craniectomy and subsequent cranioplasty remains insufficiently characterized, particularly with respect to postoperative neuralgiform pain topography. We prospectively evaluated a two-year cranioplasty cohort to characterize secondary postoperative headache syndromes and to identify clinically recognizable topographic patterns of neuralgiform cranial pain. Methods: We conducted a prospective observational study of 84 consecutive patients who underwent cranioplasty after prior decompressive craniectomy during a two-year period at a tertiary neurosurgical center. All patients constituted the source cohort. A predefined high-disability subgroup with modified Rankin Scale score > 3 was used for detailed phenotype extraction and descriptive analysis. Because headache is a subjective symptom and neurological disability may affect symptom perception, communication, and documentation, headache frequencies derived from this subgroup were interpreted as descriptive and hypothesis-generating rather than as unbiased population-level incidence estimates. Available preoperative records were reviewed for pre-existing migraine, trigeminal neuralgia, chronic headache, or facial pain. Results: Among 84 cranioplasty patients, 34 met the predefined high-disability threshold. Within this subgroup, 22 patients had documented clinically meaningful postoperative secondary headaches, corresponding to 26.2% of the full source cohort and 64.7% of the enriched subgroup. These proportions should be interpreted as documented frequencies within a clinically selected subgroup rather than as generalizable incidence rates. Detailed free-text review showed that these cases were better classified within post-traumatic and persistent post-craniotomy/post-craniectomy headache frameworks than as a single uniform syndrome. Among 12 cases with sufficiently localizable neuralgiform topography, 8 were occipital-predominant and 4 were supraorbital/frontal-predominant. The remaining cases were diffuse, mixed, facial-trigeminal, or insufficiently localized for reliable anatomic subclassification. Conclusions: Postoperative headache after decompressive craniectomy and cranioplasty appears to represent a heterogeneous spectrum of secondary postoperative headache syndromes rather than a single distinct entity. Within this spectrum, a neuralgiform subgroup can be identified, most commonly with occipital predominance and less often with supraorbital/frontal localization. These findings support more systematic postoperative pain phenotyping and may guide anatomically targeted evaluation and management, while requiring validation in larger cohorts using standardized headache instruments.