Unilateral hypoplasia of the rostral end of the superior sagittal sinus

BACKGROUND AND PURPOSE

Hypoplasia of the rostral third of the SSS is a well-known variant and constitutes the most frequent variation of the SSS after preferential drainage to one of the transverse sinuses. Our aim was to describe unilateral hypoplasia of the rostral end of the SSS.

MATERIALS AND METHODS

CTA performed in 100 consecutive patients studied for conditions other than dural sinus thrombosis was reviewed for the presence of a unilateral or bilateral hypoplastic rostral SSS. Associated dural venous sinus anomalies were recorded as well. The angiographic anatomy of unilateral hypoplastic rostral SSS was illustrated by 2 cases further imaged with DSA.

RESULTS

Unilateral hypoplastic rostral SSS was found in 7 patients (7%). In all cases, compensatory drainage occurred through a large superior frontal vein that joined the SSS in the region of the coronal suture. Three of the 7 patients with a unilateral hypoplastic rostral SSS had at least another dural venous sinus anomaly. Complete or bilateral hypoplastic rostral SSS was noted in 3 patients (3%).

CONCLUSIONS

Unilateral hypoplastic rostral SSS is more than twice as frequent as bilateral hypoplastic rostral SSS. It is the most frequently encountered variation of the SSS. Knowledge of this anatomic variation is important to avoid diagnostic pitfalls and to avoid erroneously mistaking it for a thrombosis. Four types of variations of the rostral SSS may be identified: 1) classic anatomy with a fully developed rostral SSS; 2) duplication of the rostral SSS; 3) complete or bilateral hypoplastic rostral SSS; 4) unilateral hypoplastic rostral SSS. The 4 types of rostral SSS variations can be explained by studying the embryologic development of the SSS.

Combination of rare right arterial variation with anomalous origins of the vertebral artery, aberrant subclavian artery and persistent trigeminal artery. A case report

A 32-year-old woman hospitalized for subarachnoid hemorrhage showed rare arterial variation on the right side with anomalous origins of the vertebral artery, aberrant subclavian artery and persistent trigeminal artery. Angiography showed the right vertebral artery to originate from the right common carotid artery, the right subclavian artery to arise separately from the descending aorta, and persistent trigeminal artery on the right side. The possible embryonic mechanism of this previously unreported variant combination is discussed.

Transient hemiageusia in cerebrovascular lateral pontine lesions

Knowledge of human central taste pathways is largely based on textbook (anatomical dissections) and animal (electrophysiology in vivo) data. It is only recently that further functional insight into human central gustatory pathways has been achieved. Magnetic resonance imaging studies, especially selective imaging of vascular, tumoral, or inflammatory lesions in humans has made this possible. However, some questions remain, particularly regarding the exact crossing site of human gustatory afferences. We present a patient with a pontine stroke after a vertebral artery thrombosis. The patient had infarctions in areas supplied by the anterior inferior cerebellar artery and showed vertical diplopia, right sided deafness, right facial palsy, and transient hemiageusia. A review of the sparse literature of central taste disorders and food preference changes after strokes with a focus on hemiageusia cases is provided. This case offers new evidence suggesting that the central gustatory pathway in humans runs ipsilaterally within the pons and crosses at a higher, probably midbrain level. In patients with central lesions, little attention has been given to taste disorders. They may often go unnoticed by the physician and/or the patient. Central lesions involving taste pathways seem to generate perceptions of quantitative taste disorders (hemiageusia or hypogeusia), in contrast to peripheral gustatory lesions that are hardly recognised as quantitative but sometimes as qualitative (dysgeusia) taste disorders by patients.

The perianeurysmal environment: influence on saccular aneurysm shape and rupture

PURPOSE

The purpose of this study was to evaluate whether interactions between intracranial cerebral saccular aneurysms and the perianeurysmal environment (PAE), in the form of contact constraints, influence aneurysm shape and risk of rupture.

METHODS

A total of 190 consecutive aneurysms during a 34-month period were retrospectively analyzed. Of these, 124 were ruptured (group 1) and 66 were unruptured (group 2). Pretreatment high-resolution CT angiography was available for each aneurysm and was the determinant inclusion criterion. Aneurysm size and location, type of hemorrhage, initial Glasgow Coma Scale rating, World Federation of Neurological Societies grade, Fisher grade, and presence of concomitant aneurysms were recorded. Contact constraints between aneurysms and anatomical structures of the PAE were identified for each aneurysm and further subdivided into balanced or unbalanced depending on whether contact constraints occurred symmetrically on the aneurysm wall. Regular or irregular shape was recorded and correlated to contact constraints.

RESULTS

Compared with unruptured aneurysms, ruptured aneurysms were found to be larger and more irregular, to develop more contact constraints with the PAE, and to show higher rates of unbalanced contact constraints. Ruptured aneurysms had a tendency to be found in locations of a constraining PAE. Irregular shape was positively correlated with the presence of an unbalanced contact constraint, even in the absence of obvious contour deformations from an imprint of an adjacent structure.

CONCLUSION

The existence of contact constraints between intracranial saccular aneurysms and the PAE were shown to influence shape and risk of aneurysm rupture. Modifications of wall shear stress by contact constraints are discussed. Analysis of contact constraints between aneurysm and the PAE could be considered additional parameters in the assessment of risk of aneurysm rupture.

Anomalous intracranial drainage of the nasal mucosa: a vein of the foramen caecum?

The existence of the vein of the foramen caecum (VFC) in humans is still controversial. We present 2 patients with intracranial drainage of the nasal mucosa by a frontal cortical vein into a superior sagittal sinus, demonstrated by digital subtraction angiography. In both, the position of the intracranial passage was found to be slightly paramedian. An analogy to the VFC is made.

Is the rupture of cerebral berry aneurysms influenced by the perianeurysmal environment?

PURPOSE

To evaluate contact between cerebral berry aneurysms and the perianeurysmal environment and to study the influence this contact has on aneurysm rupture.

MATERIALS AND METHODS

In a series of 76 consecutive patients, pre- and post-contrast CT images of 87 aneurysms were evaluated. Aneurysm locations were identified and aneurysms were divided into two different groups depending on whether they had ruptured or not. Contact between aneurysms and the perianeurysmal environment was studied when present, and considered to be balanced or unbalanced according to symmetry of contact and type of contact interface, i.e. with bone, dura, etc.

RESULTS

Rupture occurred in 47 aneurysms at an average maximum dome size of 7.4 mm. There was contact with elements of the perianeurysmal environment in 38 (81%) of ruptured cases and no evidence of contact in 7 (15%). The nature of contact was unclear in 2 (4%) ruptured aneurysms. In the aneurysms with contact, the nature of contact was unbalanced in 34 (72%) and balanced in 4 (9%). Unbalanced aneurysms ruptured at significantly smaller sizes (average: 7.7 mm) than balanced aneurysms (average: 11.4 mm). Seven aneurysms of small size (3.3-6.9 mm, average: 4.8 mm) were found to have ruptured, despite the fact that they were too small to exhibit contact with the perianeurysmal environment. In 40 unruptured aneurysms (average size: 6.3 mm), contact with the perianeurysmal environment was found in 15 aneurysms, for which balanced contact was found in 11 (27.5%) and unbalanced contact in 4 (10%), and no contact in 25 (62.5%). The average size of the aneurysms without contact (3.7 mm) was significantly smaller than that with balanced contact (10.3 mm) or with unbalanced contact (11.3 mm).

CONCLUSION

Aneurysms exhibit contact with their perianeurysmal environment as soon as they reach a size that exceeds their allowance given by the local subarachnoid space. The contact with the environment was found to be an additional determinant parameter in the evolution of cerebral berry aneurysms and their risk to rupture.

Angiographic anatomy of the laterocavernous sinus

BACKGROUND AND PURPOSE

The laterocavernous sinus (LCS) has recently been recognized as one of the major drainage pathways of the superficial middle cerebral vein (SMCV). Our purpose was to investigate the drainage pattern of the SMCV, with special emphasis on the angiographic anatomy of the LCS.

METHODS

The drainage pathways of the SMCV were evaluated prospectively on 100 selective carotid angiograms obtained in 65 consecutive patients.

RESULTS

The SMCV was absent in 19% of cases. A classic termination into the cavernous sinus (CS) was found in 20%, a paracavernous sinus in 39%, and an LCS in 22%. The LCS drained toward the pterygoid plexus (27%), the superior petrosal sinus (18%), the posterior aspect of the CS (32%), or a combination of these pathways (23%). A complete absence of connection between the LCS and CS was observed in 63.5% of the patients.

CONCLUSION

The LCS is a laterosellar venous space that is anatomically and angiographically distinct from the CS. Secondary small anastomoses between the LCS and CS may make it difficult to differentiate the two structures. Appreciation of the course and connection pattern of the LCS is important, particularly when planning an endovascular approach to treatment of lesions in the region of the CS.

Pathology findings with acrylic implants

We report the pathological findings in cases of acrylic implants obtained by direct intratumoral injection of polymethyl-methacrylate (PMMA) and N-butyl-cyano-acrylate (NBCA). Direct intratumoral injection of acrylic implants was performed for a variety of primary and secondary bone lesions. These types of treatments have been used at our institution in the last 4 years for 40 vertebroplasty (PMMA) procedures and for nine bone lesions of other locations (PMMA, NBCA). Postmortem histology became available for 1 case of PMMA and for 5 cases with NBCA intratumoral acrylic implants. The pathological findings associated with PMMA and NBCA were evaluated and compared. PMMA exhibited a macroscopic and microscopic rim of tumor necrosis, 6 months after implantation. NBCA exhibited compressive effects on the nearby tumor tissue, however, without signs of significant necrosis outside the acrylic tumor cast. Tumor captured inside the acrylic cast showed extensive to near complete necrosis. Acrylic implants may lead to necrosis when injected directly in tumors. The necrotizing effect may extend beyond the limits of an implant in the case of PMMA. Such an extended effect of PMMA, when compared with NBCA, may be due to the variable toxicity of acrylic implants, including the different degrees of the exothermic reaction during polymerization.

Vertebroplasty: clinical experience and follow-up results

This study was undertaken to report the clinical experience with percutaneous minimal invasive vertebroplasty using polymethyl-methacrylcate (PMMA) for a consecutive group of patients. Over the period of the last 4 years, 40 patients were treated at 68 vertebral segment levels with the intention to relieve pain related to vertebral body lesions. Reduced vertebral body height and destruction of the posterior vertebral wall were not considered to be exclusion criterias. The vertebroplasty procedure was performed under general anesthesia and in prone position with imaging control using mostly biplane DSA fluoroscopic guidance, and rarely with single-plane mobile DSA combined with computed tomographic guidance. Unilateral, but more frequently bilateral, transpedicular introduction of a 2-3-mm OD needle was followed by an injection of polymethyl-methacrylcate (PMMA). PMMA preparation involved a diluted mixture (20 mL powder for 5 mL liquid) allowing for an extended polymerization time of up to 8 min. The PMMA was mixed with metallic powder to enhance its radio-opacity. Before PMMA injection, a vertebral phlebography was obtained to evaluate the filling pattern and identify sites of potential PMMA leakage. Injection of opacified PMMA was performed under continuous visual control with fluoroscopy to obtain adequate filling and to avoid important PMMA leakage. Clinical follow-up involved an evaluation using a questionnaire for assessment of pain, pain medication, and mobility. One to six levels were treated in one to three treatment sessions for patients with metastatic, osteoporotic, and hemangiomatous lesions of the vertebral bodies who presented with pain. The results observed matched those reported previously with a success rate of approximately 80% and a complication rate below 6% per treated level. Treatment failure and complications observed were related to leakage, insufficient pretreatment evaluation, anesthesia, or patient position during treatment. Image guidance with fluoroscopy was efficient both for precise transpedicular approach and PMMA implantation control. Vertebroplasty is very efficient for treatment of pain. Treatment failure was mostly related to insufficient pretreatment clinical evaluation, and complication due to excessive PMMA volume injection. Control of PMMA volume seems to be the most critical point for avoiding complications. A good fluoroscopy control is therefore mandatory.