Hypoplasia of the Tentorium Cerebelli: Case Report and Review of the Literature.

The second largest intracranial specialization of the dura mater, the tentorium cerebelli, is a transverse fold that partially separates the cerebellum and cerebral hemispheres. During routine dissection of the posterior cranial fossa, a left-sided hypoplastic region of the tentorium cerebelli was observed. This fenestration was seen at the posterior portion of the tentorium as a posteromedial strip of tissue rising vertically to interface with the falx cerebri. Although isolated cases of tentorial hypoplasia have been reported in, for example, cases of Chiari II malformation, we believe isolated fenestration of this membrane is very rare, especially in the absence of the Chiari II malformation. The current case adds to the sparse literature on isolated tentorial defects and might be of interest to neurosurgeons or clinicians who review intracranial imaging.

Improving long-term outcomes in pediatric torcular dural sinus malformations with embolization and anticoagulation: a retrospective review of The Hospital for Sick Children experience.

OBJECTIVE: Torcular dural sinus malformations (tDSMs) are rare pediatric cerebrovascular malformations characterized by giant venous lakes localized to the midline confluence of sinuses. Historical clinical outcomes of patients with these lesions were poor, though better prognoses have been reported in the more recent literature. Long-term outcomes in children with tDSMs are uncertain and require further characterization. The goal of this study was to review a cohort of tDSM patients with an emphasis on long-term outcomes and to describe the treatment strategy. METHODS: This study is a single-center retrospective review of a prospectively maintained data bank including patients referred to and cared for at The Hospital for Sick Children for tDSM from January 1996 to March 2019. Each patient's clinical, radiological, and demographic information, as well as their mother's demographic information, was collected for review. RESULTS: Ten patients with tDSM, with a mean follow-up of 58 months, were included in the study. Diagnoses were made antenatally in 8 patients, and among those cases, 4 families opted for either elective termination (n = 1) or no further care following delivery (n = 3). Of the 6 patients treated, 5 had a favorable long-term neurological outcome, and follow-up imaging demonstrated a decrease or stability in the size of the tDSM over time. Staged embolization was performed in 3 patients, and anticoagulation was utilized in 5 treated patients. CONCLUSIONS: The authors add to a growing body of literature indicating that clinical outcomes in tDSM may not be as poor as initially perceived. Greater awareness of the lesion's natural history and pathophysiology, advancing endovascular techniques, and individualized anticoagulation regimens may lead to continued improvement in outcomes.

[Definitions and MR imaging of duropathies].

Kumar defined duropathies as disorders with dural defects-related cerebrospinal fluid leaks, particularly of spinal anterior dura mater, Superficial (hemo) siderosis (SS) and multisegemental amyotrophy (MSAM) were included in duropathies. Dural defects of SS had two types; one was incomplete closure of the dura in the spinal and cranial operations, the other was a spontaneous defect in the spinal anterior dura mater. In a majority of SS patients, spontaneous dural defects were detected at the levels of C7/Th1 to Th2/Th3 on axial FIESTA (fast imaging employing steady state acquisition) images. Similarly, dural defects in our 6 cases with MSAM were showed at C7/Th1 to Th2/Th3. Axial FIESTA images were crucial on MR imaging. T2 weighted images demonstrated abnormal hyperintense lesions in both anterior horns at the level of C3 spinal cord in all of 7 patients with MSAM. A dural defect in one case was not found.

Two cases of persistent falcine and occipital sinuses.

BACKGROUND: The coexistence of falcine and occipital sinuses is rare and its natural course has not been reported. CASE REPORTS: Two patients with persistent falcine and occipital sinuses are described. Both patients had straight sinuses. In one, both the transverse and sigmoid sinuses were hypoplastic and the patient had an acquired Chiari I malformation. The other patient had no other venous anomalies and had a normal posterior cranial fossa. CONCLUSION: The coexistence of falcine and occipital sinuses can lead to an acquired Chiari I malformation. These cases suggest the importance of checking other venous and brain anomalies in this situation.

Natural Dural Defect of the Posterior Fossa Dura as a Risk Factor for Postoperative Cerebrospinal Fluid Leakage.

BACKGROUND: During microvascular decompression surgery (MVD), small (2-3 mm diameter) natural dural defects have been noticed occasionally but never reported. These tiny dural defects cannot be detected by preoperative imaging studies or even in anatomical cadaver dissection, but may lead to complications including cerebrospinal fluid (CSF) leakage. Our objective was to analyze the features of these natural defects in the posterior fossa dura. METHODS: Surgical reports and videos of 593 consecutive patients who underwent MVD surgery for trigeminal neuralgia (TN) or hemifacial spasm (HFS) were analyzed retrospectively. Video recording confirmed that these small holes were not related to the craniotomy procedure itself and were natural defects. RESULTS: Such natural defects of the posterior fossa dura were found in 6 of the 593 patients. All of the defects were about 2 mm in diameter and occurred on the left side in female patients with HFS. All were managed by patching with a fascial or muscle graft. Multivariate analysis showed that the defect was significantly associated with the left side and had a female predilection. Neither disease (HFS or TN) nor age was correlated with the presence of dural defects. CONCLUSIONS: After posterior fossa craniotomies, CSF leakage or pseudomeningocele may occur at the dural suture site because of the hydrostatic pressure. Because such natural dural defects may be a cause of CSF complications after posterior fossa surgery, their possible occurrence should be considered. This is the first report to document the occurrence of such natural defects of the posterior fossa dura.

The fetal falx cerebelli.

BACKGROUND: The falx cerebelli is a retrocerebellar dural reflection. The MR spectrum of the fetal falx cerebelli has not been described. OBJECTIVE: To determine the prevalence of falx cerebelli abnormalities in the context of posterior fossa malformations and compare them to age-matched normal fetal MRI exams. MATERIALS AND METHODS: We reviewed all consecutive fetal MRIs performed over 1 year at a children's hospital. We assessed the falx cerebelli in each examination for location, morphology, size and number. Exams were grouped into (1) normal or non-brain/head abnormalities or (2) abnormal brain or craniofacial structures. We used chi square, linear regression and logistic regression analyses; P<0.05 was considered significant. RESULTS: We included 424 examinations (223 controls, 201 malformations) from 378 patients (mean gestational age 27±6 weeks). In the control group, the mean falx size was 2.6±1.2 mm (anteroposterior) × 11.0±3.2 mm (craniocaudal), with 80% retrovermian centered; the falx was linear (23%), Y-shape (15%), V-shape (22%) or U-shape (21%); it was unusually multiplicated (17%) or absent (<2%). Falx cerebellar abnormalities were more common in abnormal exams (59%; 119/201) than in normal exams (19%; 43/223) (P<0.001). The falx was abnormal with Blake pouch cysts (9/9, 100%) and rhombencephalosynapsis (3/4, 75%), absent in all Chiari II (n=9) and most Dandy-Walker malformations (5/6, 83%), commonly multiplicated in mega cisterna magna (14/22, 64%), and deviated or absent in cases with arachnoid cysts (3/3, 100%) and adhesions (4/5, 80%). CONCLUSION: Structural alterations of the falx cerebelli are more prevalent in fetuses with brain and craniofacial abnormalities. Specific changes offer clues to posterior fossa diagnoses.

Fístula arteriovenosa dural espinal: a propósito de un caso / Spinal dural arteriovenous fistula: a case report

Las fístulas arteriovenosas durales medulares son malformaciones vasculares adquiridas que constituyen una causa muy infrecuente de mielopatía progresiva (5-10 casos por millón de habitantes por año). La resonancia magnética es el estudio por imágenes de elección para su diagnóstico. A continuación presentamos el caso de una paciente femenina de 89 años, que consultó a la guardia de nuestra institución por un cuadro de paraparesia moderada asociada a parestesias e incontinencia urinaria posterior a esfuerzo físico. Se le diagnosticó una fístula arteriovenosa dural medular como causante de su cuadro. (AU)

Spinal dural arteriovenous fistulas (SDAVF) are acquired spinal vascular malformations and a rare cause of progressive myelopathy (5-10 new cases per year and per 1 million inhabitants). Magnetic resonance imaging is the diagnosis modality of choice. We present a case of a 89-year-old female patient who consulted the emergency department of our institution because of paraparesis and lower extremities paresthesias associated with urinary incontinence post physical effort. With the final diagnosis of spinal dural arteriovenous fistula, as a cause of the clinical symptoms. (AU)

Complications of Insufficient Dura and Blood Loss During Surgical Intervention in Shprintzen-Goldberg Syndrome: A Case Report.

BACKGROUND Shprintzen-Goldberg syndrome (SGS) is an extremely rare collagenopathy, most often caused by autosomal-dominant mutations in the SKI proto-oncogene, which is a component of the transforming growth factor beta (TGF-ß) signaling pathway. Approximately 50-60 cases of SGS have been recorded in the literature worldwide since its discovery in 1982. This collagen disorder affects bone and vascular development throughout the body, resulting in craniosynostosis, scoliosis, chest deformities, and aortic root dilation. Patients may have problems in the central nervous system, including Chiari 1 malformation, hydrocephalus, and dilation of the lateral ventricles. Unfortunately, the symptoms of SGS closely parallel those of related collagenopathies involving mutations in the TGF-ß signaling pathway, which makes accurate diagnosis difficult without genetic testing, especially in cases with complex presentation. CASE REPORT In this report we present the unique and complex disease manifestations in a 9-year-old girl with SGS. The patient had severe cervical spinal instability that resolved after surgical occipital-C4 fusion with an autograft from the rib. Midface distraction surgery was used to treat the patient's craniosynostosis and related facial deformities. This surgery was complicated by loss of 750 mL of blood due to insufficient dura and prominent vasculature. CONCLUSIONS Connective tissue symptoms associated with SGS can involve dural and vascular problems, as seen in this case report. Thus, the risk of extreme blood loss should be anticipated any time midface distraction surgery is performed on an SGS patient. Continued research is needed to define how this case relates to the SGS patient population.

Morphometric analysis of spinal cord termination in Cavalier King Charles Spaniels.

BACKGROUND: There is an association between Chiari malformations, syringomyelia (CMSM) and tethered cord syndrome (TCS) in people, suggesting Cavalier King Charles Spaniels (CKCS) with CMSM could also have TCS. Currently there are no data on the position of the caudal spinal cord structures in CKCS. OBJECTIVE: To describe and compare location of spinal cord termination in CKCS with weight-matched controls and to examine the relationship between SM and spinal cord termination. ANIMALS: Thirty-nine CKCS and 33 controls with thoracolumbar MRIs; 34 of 39 CKCS also had cervical MRIs. METHODS: Blinded retrospective study. Spinal cord and dural sac termination were determined from T2-weighted sagittal and transverse images and half-Fourier acquisition single-shot turbo spin echo sequences. Intra-observer reliability was determined using kappa analysis. Presence of SM was compared with location of spinal cord and dural sac termination. RESULTS: Intra-observer reliability was moderate for identifying spinal cord termination (Kappa = 0.6) and good for dural sac termination (Kappa = 0.8). The spinal cord terminated at lumbar vertebra 6 (L6) in 1, 7 (L7) in 22, and sacrum in 16 CKCS versus 9 at L6, 23 at L7, 1 at sacrum in controls. Spinal cord (P < .001) and dural sac (P = .002) termination were significantly more caudal in CKCS compared to controls. The presence of thoracolumbar SM was associated with more caudal dural sac termination in CKCS (P = .03). CONCLUSIONS AND CLINICAL IMPORTANCE: The relationship between TL SM and possible spinal cord tethering because of a more caudal dural sac termination should be investigated.

Imaging of Cerebral Arteriovenous Malformations and Arteriovenous Fistulas and Occlusion Control Using Intraoperative 3-Dimensional Rotational Fluoroscopy.

BACKGROUND: Intraoperative resection or occlusion control is indispensable in the surgery of vascular anomalies. This can be conducted using local vascular imaging modalities or angiographic techniques. This series was performed to assess whether cerebral arteriovenous malformations (AVMs) and dural arteriovenous fistulae (dAVFs) can be detected in a sufficient quality by intraoperative 3-dimensional (3D) fluoroscopy with intravenous contrast application. MATERIALS AND METHODS: Five patients were included in the analysis (2 AVMs, 3 dAVFs). All patients had preoperative digital subtraction angiography. The head was fixed in a carbon MAYFIELD clamp. After a 3D rotational fluoroscopy scan without contrast agent, a second scan with 50 mL of iodine contrast agent was performed. The Digital Imaging and Communications in Medicine data of both scans were subtracted and reconstructed using the OsiriX imaging software. In 2 patients with dAVF, occlusion control was performed after obliteration of the fistula. RESULTS: In the 2 patients with cerebral AVM, 3D fluoroscopy with intravenous contrast administration resulted in good image quality. Preoperative embolization with Onyx produces significant artifacts that can be largely removed by simple digital subtraction techniques. In dural AVF, occlusion control was well feasible after obliteration of the draining vein at its dural origin. CONCLUSIONS: This technique quickly supplies intraoperative images of adequate quality to locate cerebral AVM and dAVF. However, it does not produce dynamic images. Thus, early draining veins cannot be located unless anatomically identified based on the preoperative DSA. In this case, it can be used for intraoperative obliteration control.

Risk Factors and Management of Dural Defects in Anterior Surgery for Cervical Ossification of the Posterior Longitudinal Ligament.

OBJECTIVE: To investigate risk factors and outcomes and to develop a cogent perioperative management algorithm for dural defects (DDs) in anterior surgery for cervical ossification of the posterior longitudinal ligament (OPLL). METHODS: Ninety OPLL patients who had undergone anterior cervical decompression between January 2014 and December 2016 were reviewed. DDs occurred in 12 patients. Demographic, clinical, and radiologic data; intraoperative and postoperative management; and complications were analyzed. Risk factors for DDs were assessed with multivariate analysis. A treatment algorithm was identified based on these findings and our experience. RESULTS: The prevalence of DDs was 13.3% (12/90). Univariate and multivariate analyses showed that the ratio of OPLL base to spinal canal (odds ratio [OR] 1.09, P = 0.012), kyphotic cervical alignment with thick OPLL masses (OR 9.44, P = 0.026), and lateral, curved, and irregular OPLL masses (OR 8.28, P = 0.037) could be risk factors for DDs. DDs were repaired intraoperatively with onlay grafts, and lumbar drains were placed in all DD patients. The treatment was successful in all DD patients, and outcome measures did not differ between the DD and no DD groups. No patient had experienced complications associated with DDs and CSF leaks at the final follow-up visit. CONCLUSIONS: Patients with broad-based OPLL, kyphotic cervical alignment with thick OPLL masses, and lateral, curved, and irregular OPLL masses have a higher risk of DD in anterior surgery for OPLL. Intraoperative primary repair with onlay grafts combined with early lumbar drains is a simple, safe, and effective strategy for DDs. The outlook for the long-term sequelae of DDs is optimistic if they are managed adequately.

Failure pressures after repairs of 2-cm × 2.5-cm rhinologic dural defects in a porcine ex vivo model.

BACKGROUND: The objective of this study was to determine failure pressures of 6 rhinologic repair techniques of large skull base/dural defects in a controlled, ex vivo model. METHODS: Failure pressures of 6 dural repairs in a porcine model were studied using a closed testing apparatus; 24-mm × 19-mm dural defects were created; 40-mm × 34-mm grafts composed of porcine Duragen (Integra), fascia lata, and Biodesign (Cook) were used either with or without Tisseel (Baxter International Inc.) to create 6 repairs: Duragen/no glue (D/NG), Duragen/Tisseel (D/T), fascia lata/no glue (FL/NG), fascia lata/Tisseel (FL/T), Biodesign/no glue (B/NG), and Biodesign/Tisseel (B/T). Saline was infused at 30 mL/hour, applying even force to the underside of the graft until repair failure. Five trials were performed per repair type for a total of 30 repairs. RESULTS: Mean failure pressures were as follows: D/NG 1.361 ± 0.169 cmH2 O; D/T 9.127 ± 1.805 cmH2 O; FL/NG 0.200 ± 0.109 cmH2 O; FL/T 7.833 ± 2.657 cmH2 O; B/NG 0.299 ± 0.109 cmH2 O; and B/T 2.67 ± 0.619 cmH2 O. There were statistically significant differences between glued (Tisseel) and non-glued repairs for each repair category (p < 0.05). CONCLUSION: All glued repairs performed better than non-glued repairs. Both D/T and FL/T repairs performed better than B/T repairs. No repair tolerated pressures throughout the full range of adult supine intracranial pressure.

Dural Arteriovenous Fistula Could Be Due to Hemodynamic Disturbance in Dural Physiological Shunts? Histopathological Study and a Case Report.

BACKGROUND: Histopathologic studies of dural arteriovenous fistulas (dAVFs) are important for clarifying the pathogenesis. We present a case of Cognard type IV dAVF with detailed histopathologic studies in correlation with radiologic and intraoperative findings. CASE DESCRIPTION: An otherwise asymptomatic 53-year-old man presented with chronic headache. Neurologic examination revealed no abnormalities. Neuroimaging and cerebral catheter angiographic studies disclosed a left frontoparietal dAVF close to the middle third of the superior sagittal sinus, fed by the left superficial temporal and bilateral middle meningeal arteries and draining into ectatic cortical and dural veins. No evidence of superior sagittal sinus thrombosis or occlusion was seen. Intraoperatively, the parietal branch of the left superficial temporal artery penetrated the skull vault to feed the fistula; arterialized cortical and draining dural veins were also noted. Complete obliteration of the dAVF with removal of the affected dura mater was achieved safely. Histopathologic studies in serial sections documented a shunt point between the dural artery and the dural vein within the dura mater and a draining point between the dural and cortical veins. CONCLUSIONS: On the basis of clinical, angiographic, intraoperative, and histologic findings in our case, we strongly excluded acquired etiologies.

Reconstructing spinal dura-like tissue using electrospun poly(lactide-co-glycolide) membranes and dermal fibroblasts to seamlessly repair spinal dural defects in goats.

Many neuro- and spinal surgeries involving access to the underlying nervous tissue will cause defect of spinal dural mater, further resulting in cerebrospinal fluid leakage. The current work was thus aimed to develop a package which included two layers of novel electrospun membranes, dermal fibroblasts and mussel adhesive protein for repairing spinal dural defect. The inner layer is electrospun fibrous poly(lactide-co-glycolide) membrane with oriented microstructure (O-poly(lactide-co-glycolide)), which was used as a substrate to anchor dermal fibroblasts as seed cells to reconstitute dura-like tissue via tissue engineering technique. The outer layer is chitosan-coated electrospun nonwoven poly(lactide-co-glycolide) membrane (poly(lactide-co-glycolide)-chitosan). During surgery, the inner reconstituted tissue layer was first used to directly cover dura defects, while the outer layer was placed onwards with its marginal area tightly immobilized to the surrounding normal spinal dura aided by mussel adhesive protein. Efficacy of the current design was verified in goats with spinal dural defects (0.6 cm × 0.5 cm) in lumbar. It was shown that seamless and quick sealing of the defect area with the implants was realized by mussel adhesive protein. Guided tissue growth and regeneration in the defects of goats were observed when they were repaired by the current package. Effective cerebrospinal fluid containment and anti-adhesion of the regenerated tissue to the surrounding tissue could be achieved in the current animal model. Hence, it could be ascertained that the current package could be a favorite choice for surgeries involving spinal dural defects.

Early two-stage repair of clefts in holoprosencephaly.

UNLABELLED: Holoprosencephaly (HPE) presents with a spectrum of severity, but in its totality is the most common malformation of the embryonic forebrain occurring 1 in 10,000 to 1 in 20,000 live births. Due to the poor prognosis, treatment of mid-face clefts in HPE patients have classically been addressed in a delayed fashion after 1-year of age. Improvements in the ability to manage medical complications associated with HPE along with an increased understanding and lower mortality rates in less severe forms have challenged these previous practiced routines. Accompanied by advances in understanding of HPE and identification of genes responsible for sporadic forms, we are able to better guide timing of surgical intervention. We present a patient with lobar HPE and a type IV facial deformity treated with early repair of the median facial cleft. We believe this treatment strategy was safe, given her relatively good prognosis. We propose that patients with HPE displaying less severe neural non-cleavage may be good candidates for earlier two-stage intervention. SUMMARY: The historically poor prognosis of patients with holoprosencephaly (HPE) has led to midline facial clefts have being addressed in a delayed fashion after 1-year of age. Improvements in the ability to manage medical complications associated with HPE and lower mortality rates in less severe forms have challenged these previous practiced routines. Additionally, the identification of genes responsible for sporadic forms of HPE can better guide timing of surgical intervention and improve developmental outcomes. We present a patient with lobar HPE and a type IV facial deformity treated with an early two-stage repair of the median facial cleft. We propose patients with HPE displaying less severe neural non-cleavage may be good candidates for earlier intervention.

The role of percutaneous embolization techniques in the management of dural sinus malformations with atypical angioarchitecture in neonates: report of 2 cases.

Dural sinus malformations (DSMs) are rare congenital malformations that can be midline or lateral in location. Midline DSMs have been reported to have a worse prognosis than lateral DSMs and have traditionally been more difficult to manage. The authors report 2 unusual manifestations of midline DSMs and their management with percutaneous transfontanelle embolization. The first patient (Case 1) presented at 21 days of life with a large midline DSM and multiple highflow dural and pial arteriovenous shunts. The child developed congestive cardiac failure and venous congestion with intracranial hemorrhage and seizures within a few weeks. The second patient (Case 2) presented with a large midline DSM found on prenatal imaging that was determined to be a purely venous malformation on postnatal evaluation. This large malformation resulted in consumptive coagulopathy and apneic episodes from brainstem compression. The patient in Case 1 was treated initially with endovascular embolization and eventually with curative percutaneous-transfontanelle embolization. The patient in Case 2 was treated with percutaneous transfontanelle embolization in combination with posterior fossa decompression and cranial expansion surgery.