Tag: aqueduct

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True aqueductal tumors: a unique entity

True aqueductal tumors-a unique entity

Acta Neurochir (2015) 157:169–177

Pure aqueductal tumors (ATs) differ from pineal region and tectal/tegmental tumors in that they are epicentered within the aqueduct. Nevertheless, these tumors are rarely described as a separate type of tumor, and are often grouped with other lesions located in the same vicinity. The present multicenter study focuses on our experience treating patients with pure ATs.

Methods Data from three large tertiary centers was collected retrospectively, including presenting symptoms, treatment paradigm, surgical approaches, pathology, and outcome.

Results Between 1999 and 2013, 16 patients with AT were diagnosed and treated at the three tertiary centers. Ages at presentation ranged from 5.5 to 57 years. Thirteen patients presented with hydrocephalus-related symptoms, and two were identified incidentally. Thirteen patients underwent an endoscopic third ventriculostomy, and two of these underwent a simultaneous endoscopic biopsy (one grade II ependymoma, one non-specified low-grade glioma). Two others underwent shunt placement. Three patients underwent resection due to tumor progression. Pathologies included glioblastoma multiforme, glioneural tumor, and ependymoma grade II. All non-resected tumors remained stable or grew only minimally.

Conclusions ATs are a rare entities that usually present with obstructive hydrocephalus. Treatment includes primarily cerebrospinal fluid drainage (preferably via an endoscopic third ventriculostomy). Simultaneous endoscopic biopsy may be done in selected cases. Tumor resection should be reserved for growing tumors; the trans-fourth ventricular or transchoroidal approaches are probably safer than other approaches used to reach the tectal region.

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The Aqueduct of Sylvius: Applied 3-T Magnetic Resonance Imaging Anatomy and Morphometry With Neuroendoscopic Relevance

Aqueduct of Sylvius MRI morphometry

Neurosurgery 73[ONS Suppl 2]:ons132–ons140, 2013

The aqueduct of Sylvius (AqSylv) is a structure of increasing importance in neuroendoscopic procedures. However, there is currently no clear and adequate description of the normal anatomy of the AqSylv.

OBJECTIVE: To study in detail hitherto unavailable normal magnetic resonance imaging morphometry and anatomic variants of the AqSylv.

METHODS: We retrospectively studied normal midsagittal T1-weighted 3-T magnetic resonance images in 100 patients. We measured widths of the AqSylv pars anterior, ampulla, and pars posterior; its narrowest point; and its length. We recorded angulation of the AqSylv relative to the third ventricle as multiple deviations of the long axis of the AqSylv from the Talairach bicommissural line. We statistically determined age- and sexrelated changes in AqSylv morphometry using the Pearson correlation coefficient. We measured angulation of the AqSylv relative to the fourth ventricle and correlated this to the cervicomedullary angle (a surrogate for head position).

RESULTS: Patients were 13 to 83 years of age (45% male, 55% female). Mean morphometrics were as follows: pars anterior width, 1.1 mm; ampulla width, 1.2 mm; pars posterior width, 1.4 mm; length, 14.1 mm; narrowest point, 0.9 mm; and angulation in relation to the third and fourth ventricles, 26 and 18, respectively. Age correlated positively with width and negatively with length of the AqSylv. There was no correlation between AqSylv alignment relative to the foramen magnum and the cervicomedullary angle.

CONCLUSION: Normative dimensions of the AqSylv in vivo are at variance with published cadaveric morphometrics. The AqSylv widens and shortens with cerebral involution. Awareness of these normal morphometrics is highly useful when stent placement is an option during aqueductoplasty. Reported data are valuable in guiding neuroendoscopic management of hydrocephalus and aqueductal stenosis.

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Why does endoscopic aqueductoplasty fail so frequently?

J Neurosurg 117:141–149, 2012

The aim of this study was to evaluate and compare CSF flow after endoscopic third ventriculostomy (ETV) and endoscopic aqueductoplasty (EAP) in patients presenting with obstructive hydrocephalus caused by aqueductal stenosis.

Methods. In patients harboring aqueductal stenosis who underwent EAP (n = 8), ETV (n = 8), and both ETV and EAP (n = 6), CSF flow through the restored aqueduct and through the ventriculostomy was investigated using cine cardiac-gated phase-contrast MRI. For qualitative evaluation of CSF flow, an in-plane phase-contrast sequence in the midsagittal plane was used. The MR images were displayed in a closed-loop cine format. Quantitative through-plane measurements were performed in the axial plane perpendicular to the aqueduct and/or floor of the third ventricle.

Results. Evaluation revealed significantly higher CSF flow through the ventriculostomies compared with flow through the aqueducts. This was true both when comparing the ETV group with the EAP group and when comparing the flow of the ventriculostomy and aqueduct within the ETV and EAP group. There was no difference in aqueductal CSF flow between patients who underwent EAP alone and patients who underwent ETV and EAP. There was also no difference in ventriculostomy CSF flow between patients who underwent ETV alone and patients who underwent ETV and EAP. Fifty percent of the restored aqueducts became occluded at a mean of 46 months after surgery (range 18–126 months). In contrast, all ETVs remained patent in the mean follow-up period of 110 months after surgery, although 1 patient required shunt placement after 66 months.

Conclusions. Cerebrospinal fluid flow through ventriculostomies is significantly higher than aqueductal CSF flow after EAP. This could be one factor to explain why the reclosure rate of aqueducts after EAP is higher than the reclosure rate of the ventriculostoma after ETV.

 

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