Post-traumatic hydrocephalus in adults: the mechanisms of development, predictors of progression and management strategies. A narrative review and case series analysis.

Background: Post-traumatic hydrocephalus (PTH) is a common but dangerous complication of traumatic brain injury (TBI), increasing its morbidity/mortality and complicating the outcomes. It may arise abruptly or appear later following injury, and it is sometimes linked to substantial ventriculomegaly. Its etiology is complex and multifactorial, including severe TBI, subarachnoid/intracranial/intraventricular hemorrhage, and decompressive craniectomy. However, the exact mechanisms of PTH development, including cerebrospinal fluid (CSF) disturbances, supported by neuroinflammation and subarachnoid obstruction, remain inadequately determined. Consequently, managing PTH patients is demanding and logistically challenging, involving detailed diagnostics, external or V-P shunting, regular follow-ups, and treatment of complications such as CSF leaks, shunt malfunctions, obstructions, over-drainage, and infections. Methods: This narrative review aims to discuss and examine the mechanisms of PTH development in adults, predictors of its outcome/progression, and the modalities and effectiveness of its surgical management. It is based on a comprehensive review of the relevant literature and a single-center retrospective analysis of a cohort of adult PTH patients over 1 year. Results: PTH occurred in 20 (21.05%) out of a series of 95 patients who sustained a TBI for 1 year, due to CSF disturbance, triggering ventricular enlargement, and presenting with intracranial hypertension. Acute subdural hematoma was found in 14 (70.0%) patients, while midline shift/cisternal compression was present in 13 (65.0%) patients. Both parameters were strongly correlated with increased ICP, which was associated with low admission Glasgow Coma Score (GCS), severe TBI, and an unfavorable outcome. Older age was also correlated with aSDH and severe TBI, and with a bad outcome when ICP was elevated. Conclusion: Low admission GCS, aSDH, brain edema (midline shifting/basal cisternal compression), elevated ICP, and older age are strong predictors of unfavorable outcome and considerably worse prognosis in TBI patients who develop PTH. It seems that only PTH patients with a syndrome of increased intracranial pressure (ICP) require unconditional surgery, while those with chronic symptoms may be observed for PTH progression.