Pirina, Alessandro

OBJECTIVE Long-standing overt ventriculomegaly in adults (LOVA) is a form of chronic hydrocephalus and its pathophysiology and treatment remain debated. An analysis of CSF dynamics in this condition has rarely been reported. The aim of this study was to analyze hydrodynamic characteristics of patients with suspected LOVA to discuss its pathophysiological mechanisms and the importance of CSF dynamics analysis for diagnosis and treatment of these patients. METHODS This retrospective cohort study, conducted between May 2018 and October 2022, included adult patients aged > 18 years investigated in a department of neurosurgery through a lumbar infusion study for suspicion of LOVA (n = 23). These patients were then compared with a control cohort explored for suspicion of idiopathic normal pressure hydrocephalus (iNPH; n = 30). Clinical symptoms, radiological findings, and hydrodynamic parameters were analyzed. The authors specifically compared two hydrodynamic parameters: resistance to CSF outflow, or Rout, which relies on CSF resorption, and pressure-volume index (PVI), which reflect overall craniospinal compliance. The lumbar infusion study was considered pathological (confirming the diagnosis of chronic hydrocephalus) when at least one of these two parameters was altered. RESULTS Rout was significantly less frequently increased (cutoff ≥ 12 mm Hg/ml/min) in patients with LOVA (52%) than in those with iNPH (97%; p < 0.001). In contrast, PVI was impaired (cutoff ≤ 25 ml) in both cohorts, i.e., in 61% of patients with LOVA and in 83% of patients with iNPH. Overall, the rate of pathological lumbar infusion study in LOVA (87%) was not statistically different than in iNPH (100%). However, PVI was the only impaired parameter most frequently found in those with LOVA (35%) compared with those with iNPH (3%; p = 0.002). CONCLUSIONS This study suggests that there is a differential CSF dynamics pattern when comparing patients with LOVA versus those with iNPH. A higher proportion of patients with LOVA showed isolated compliance impairment. These findings highlight the utility of CSF dynamics analysis for the evaluation of patients with suspected chronic obstructive hydrocephalus such as LOVA. Future research with larger case series may help define diagnosis and treatment algorithms of chronic obstructive hydrocephalus based on CSF dynamics analysis, in addition to clinical and radiological criteria.

Abstract This is a case of a 73 yr-old female presenting with low back pain and bilateral sciatic pain, which progressed to bilateral lower extremity weakness about 1 yr after initial presentation. Imaging of her thoraco-lumbar spine revealed a ventriculus terminalis extending from the level of the eleventh thoracic vertebra (T11) to the first lumbar vertebra (L1). Ventriculus terminalis is an embryological ependymal lined cavity that normally regresses with development. In individuals with persistent ventriculus terminalis, it is usually incidentally noted during spine imaging for other purposes. Surgery is seldom indicated except for patients presenting with progressive neurological deficits. Patient was taken to surgery for fenestration of the ventriculus and decompression of the spinal canal. The patient was positioned prone, and after proper localization the vertebral column was exposed through a midline approach and a central laminectomy was performed from T11-L1. Intraoperative monitoring was used throughout the procedure. This video illustrates the gross appearance of a ventriculus terminalis, dissection of surrounding neural elements, and decompression of the ventriculus using a wide fenestration technique. All relevant patient identifiers have been removed from the video. Nevertheless, patient consent was obtained regarding video recording and redistribution of procedure for educational purposes.