Cranioplasty complications in severe traumatic brain injury: implications of timing of surgery, implant material and incidence of vetriculomegaly versus Post-Traumatic hydrocephalus

Background Despite the increasing number of decompressive craniectomy (DC) in neurotrauma, the optimal timing for elective cranioplasty (CP) is still debated. Little is known about the CP complications related to surgery, implant material, and post-traumatic hydrocephalus. Objectives To explore the correlation between CP timing, implant material, and the incidence of postoperative complications in patients undergoing CP after DC for severe head injuries. Materials and methods A retrospective multicenter study was conducted from January 2010 to December 2021 across 9 European neurosurgical centers. A cohort of 4007 patients who underwent CP following DC for severe head injury was analyzed. Timing was categorized as: ultra-early (< 30 days), early (31-90 days), late (> 90 days). Complications were defined according to Clavien-Dindo classification, requiring revision surgery and/or hospital readmissions. Results Among the 4007 patients, 352 (8.8%) had ultra-early CP, 1627 (40.5%), and 2028 (51.7%) had early and late CP respectively. Cerebrospinal fluid (CSF) derangement was more frequently associated with large defects and the incidence of Sinking Skin Flap Syndrome (SSFS). SSFS was more frequently diagnosed in patients undergoing late surgery whereas hydrocephalus and epilepsy were less frequently encountered in the ultra-early and early groups (p < 0,05). The overall complication rate was 24.6% (985 patients) including internal hydrocephalus (20%), infection (18%), external hydrocephalus (15%), epilepsy (15%), acute extradural (14%) or subdural hematomas (10%), and subdural hygroma (8%). CP stabilized CSF derangement in 80% of cases, which did not progress into overt hydrocephalus, whereas 17% with definite diagnosis of post-traumatic hydrocephalus required a Ventriculo-Peritoneal shunt (VPS). Simultaneous CP and VPS led to infections in all cases, regardless of implant material. Conclusion Surgery timing has a greater impact on CP complications than implant material. CSF derangement represents the single most relevant factor influencing the clinical course of patients undergoing CP.