Human Foramen Magnum Area and Posterior Cranial Fossa Volume Growth in Relation to Cranial Base Synchondrosis Closure in the Course of Child Development

Neurosurgery ◽  
2016 ◽  
Vol 79 (5) ◽  
pp. 722-735 ◽  
Author(s):  
Guillaume Coll ◽  
Jean-Jacques Lemaire ◽  
Federico Di Rocco ◽  
Isabelle Barthélémy ◽  
Jean-Marc Garcier ◽  
...  

Abstract BACKGROUND: To date, no study has compared the evolution of the foramen magnum area (FMA) and the posterior cranial fossa volume (PCFV) with the degree of cranial base synchondrosis ossification. OBJECTIVE: To illustrate these features in healthy children. METHODS: The FMA, the PCFV, and the ossification of 12 synchondroses according to the Madeline and Elster scale were retrospectively analyzed in 235 healthy children using millimeter slices on a computed tomography scan. RESULTS: The mean FMA of 6.49 cm2 in girls was significantly inferior to the FMA of 7.67 cm2 in boys (P <.001). In both sexes, the growth evolved in a 2-phase process, with a phase of rapid growth from birth to 3.75 years old (yo) followed by a phase of stabilization. In girls, the first phase was shorter (ending at 2.6 yo) than in boys (ending at 4.33 yo) and proceeded at a higher rate. PCFV was smaller in girls (P <.001) and displayed a biphasic pattern in the whole population, with a phase of rapid growth from birth to 3.58 yo followed by a phase of slow growth until 16 yo. In girls, the first phase was more active and shorter (ending at 2.67 yo) than in boys (ending at 4.5 yo). The posterior interoccipital synchondroses close first, followed by the anterior interoccipital and occipitomastoidal synchondroses, the lambdoid sutures simultaneously, then the petro-occipital and spheno-occipital synchondroses simultaneously. CONCLUSION: The data provide a chronology of synchondrosis closure. We showed that FMA and PCFV are constitutionally smaller in girls at birth (P ⩽.02) and suggest that a sex-related difference in the FMA is related to earlier closure of anterior interoccipital synchondroses in girls (P =.01).

OBJECTIVE Posterior vault distraction osteogenesis (PVDO) is an effective tool to increase intracranial volume and expand the posterior cranial fossa. During PVDO, the authors extended osteotomy posterior to the foramen magnum to fully expand the posterior cranial fossa. The aim of this study was to investigate the efficacy of complete PVDO in posterior fossa expansion and treatment of Chiari malformation type I (CM-I) in patients with craniosynostosis. METHODS Patients with craniosynostosis who had undergone complete PVDO between January 2012 and May 2020 were reviewed retrospectively. A coronal osteotomy extending to the foramen magnum was performed and the foramen magnum was decompressed by removing its posterior rim with a 1-mm Kerrison rongeur. Four distractor devices were placed and the vector of distraction was controlled from the posterior to the inferior-posterior direction, depending on the deformity. Changes in the intracranial volume, posterior cranial fossa area, and cerebellar tonsillar descent were measured after complete PVDO by using CT and MRI. RESULTS A total of 11 patients with craniosynostosis and concurrent CM-I were included in the study. The mean age was 34.6 ± 24.0 months (continuous variables are expressed as the mean ± SD throughout). One patient had sleep apnea, which was consistent with CM-I, and another patient had a headache, which was nonspecific. The intracranial volume increased from 1179.6 ± 180.2 cm3 to 1440.6 ± 251.5 cm3 (p = 0.003; 24.5% increase compared to the preoperative volume). The posterior skull base area increased from 44.9 ± 19.3 cm2 to 72.7 ± 18.1 cm2 (p = 0.004). Cerebellar tonsillar descent decreased in all 11 patients after complete PVDO (preoperative: 10.8 ± 3.7 mm, postoperative: 2.7 ± 3.0 mm; p = 0.003). Among the 11 patients, 5 showed complete resolution of cerebellar tonsillar herniation. CONCLUSIONS Complete PVDO can more efficiently expand the posterior cranial fossa, unlike conventional methods. Moreover, it helps to relieve cerebellar tonsillar herniation. Complete PVDO is a powerful tool to increase the intracranial and posterior fossa volumes in patients with craniosynostosis and concurrent CM-I.


2009 ◽  
Vol 111 (5) ◽  
pp. 1046-1052 ◽  
Author(s):  
Rémy Noudel ◽  
Nicolas Jovenin ◽  
Cristophe Eap ◽  
Bernard Scherpereel ◽  
Laurent Pierot ◽  
...  

Object The chronic tonsillar herniation defining Chiari malformation Type I (CMI) is thought to result from overcrowding of a normally developing hindbrain within a congenitally small posterior cranial fossa (PCF) due to occipital hypoplasia. The goals in the present study were to authenticate the cranioencephalic disproportion in a group of patients with CMI and to discuss new developmental aspects according to which part of the occipital bone was underdeveloped. Methods The authors retrospectively examined a group of 17 patients with CMI. Measurements of osteotentorial and neural structures of the PCF were made on MR images of the brain. The results were compared with findings in 30 healthy controls by using the Mann-Whitney U-test. Results Dimensions of the neural structures did not differ between the 2 groups of patients. The mean length of the basiocciput was significantly shorter in the CMI group (19.4 mm) compared with the control group (25.7 mm; p = 0.0003). The mean diameter of the foramen magnum was larger in the CMI group, but this difference was not statistically significant. The dimensions of the supraocciput and the mean angle of the cerebellar tentorium were identical in the 2 groups. Conclusions Data in this study support the idea that occipital hypoplasia is the main cause of overcrowding within the PCF. Basioccipital shortness is a cardinal feature of the resultant shallow PCF and could proceed from a congenital disorder of the cephalic mesoderm of the parachordal plate or occur later in the infancy because of premature stenosis of the sphenooccipital synchondrosis.


2020 ◽  
Vol 11 ◽  
pp. 92
Author(s):  
Aimee Goel ◽  
Abhidha Harshad Shah ◽  
Ravikiran Vutha ◽  
Atul Goel

Background: The effect of benign foramen magnum tumours on cranial and spinal dimensions and cerebrospinal fluid (CSF) spaces is unclear. In this study, we measured alterations in cerebrospinal fluid (CSF) spaces in the spinal canal and in the posterior cranial fossa distant from the site of benign foramen magnum tumors. Methods: Twenty-nine magnetic resonance imaging scans of patients with foramen magnum tumors (8 meningiomas and 21 C2 neurinomas) were identified for radiological morphometric analysis and compared with normal control scans. The anterior-posterior distance between the pontomedullary junction and the clivus, the spinal canal diameter, spinal cord diameter, and cord-canal ratios were measured at the C6 and T2 levels. Results: The mean spinal canal diameter was significantly higher in tumor scans at both the C6 and T2 spinal levels than in controls (13.8 mm vs. 11.4 mm at C6; p<0.0001, and 12.9 mm vs. 11.9 mm at T2; P=0.01). Further, the mean cord:canal ratio was significantly lower in tumor scans at both levels (0.49 vs. 0.64 at C6; P<0.0001, and 0.45 vs. 0.54 at T2; P=0.0009). There was no significant difference in mean anteroposterior distance from the clivus to the pontomedullary junction (10.4 mm vs. 10.3 mm; P=0.91). Conclusion: In the presence of benign foramen magnum tumors, the spinal canal diameter and CSF volume in the spinal canal increased at the C6 and T2 levels, distant from the tumor site, a phenomenon we describe as “external syringomyelia”.


2020 ◽  
Vol 8 (4.1) ◽  
pp. 7777-7781
Author(s):  
Suresh Sharma ◽  
◽  
Sakshi Mathur ◽  
Puneet Joshi ◽  
Upendra Kumar Gupta ◽  
...  

Background: The Foramen Magnum is communication between vertebral canal and posterior cranial fossa and important landmark to key structures such as brain, spinal cord, vertebral arteries. Anatomical knowledge of the foramen magnum is significant for understanding the pathophysiology of various disorders of the craniovertebral junction as well as for planning surgical procedures. Materials and Methods: The study was conducted on 62 dry skulls of unknown gender obtained from the Department of Anatomy. The shape of foramen magnum was classified as oval, round, tetragonal, pentagonal, hexagonal and irregular in shape and measurements like anterio-posterior diameter and transverse diameter of foramen magnum were taken using the Digital Vernier sliding caliper. Results: In the present study most common shape was oval in 22 (35.48%) skulls, followed by Egg shape in 12 (19.35%) skulls and least common pentagonal shape in 1(1.61%) skulls. In our study the mean anteroposterior diameter was 34.17 mm. and mean transverse diameter was observed to be 28.86 mm. Conclusion: Results of our present study may help in neurosurgeons, orthopedicians, radiologist and anesthetist in North West indian population. KEY WORDS: foramen magnum, skull, transverse diameter, oval.


1995 ◽  
Vol 112 (5) ◽  
pp. P88-P88
Author(s):  
Paul J. Donald ◽  
Bernard M. Lyons ◽  
Joao J. Maniglia

Educational objectives: To understand the relationship of deep facial structures to the cranial base and the pertinent intracranial anatomy; to perform the comprehensive workup required by skull base surgery patients; and to acquire a working knowledge of the basic skull base procedures in the anterior, middle, and posterior cranial fossa.


2021 ◽  
Author(s):  
Estelle Anne How Hong ◽  
Shalid Ahmed ◽  
Srihari Deepak ◽  
Gueorgui Kounin

Abstract Background Syringomyelia is a fluid-filled cyst within the spinal cord and usually associated with Arnold-Chiari malformation. Posterior cranial fossa tumours are a rare cause of tonsillar herniation and secondary syringomyelia. Case Presentation: We report a rare case of a 56-year-old female with posterior cranial meningioma and secondary syringomyelia, admitted with headache, nausea, vomiting, and ataxic gait. MRI demonstrated a large posterior fossa lesion causing early ventriculomegaly and syrinx within the upper spinal cord extending from the hindbrain inferiorly to the level of T8. She underwent a posterior fossa craniectomy with left C1 hemilaminectomy and complete excision of the tumour. In 6 months following her procedure, MRI scan showed a significant reduction in the calibre of the syringomyelia throughout its length and there was a significant improvement in symptoms. Literature review: A PubMed literature search was carried out with keywords: “syringomyelia”, “posterior fossa” and “tumour”. 120 articles were reviewed. The inclusion criteria for this study was posterior fossa meningioma causing syrinx formation. A total of 9 isolated similar cases were identified. Discussion Tonsillar herniation and syringomyelia secondary to posterior cranial fossa meningioma are rare. The alteration in the dynamic flow of CSF is likely to be the cause for the formation and enlargement of the syrinx. Conclusion Although the pathophysiology of syrinx formation is still poorly understood, the alteration of CSF dynamic has been implicated, but a common unifying cause appears to be increased transcranial difference in intracranial pressure across the foramen magnum causing tonsillar herniation, irrespective of location in the posterior fossa. Posterior fossa craniotomy and excision of the lesion is the mainstay treatment.


1971 ◽  
Vol 35 (6) ◽  
pp. 731-741 ◽  
Author(s):  
Georges M. Salamon ◽  
André Combalbert ◽  
Charles Raybaud ◽  
Jorge Gonzalez

✓ The meningeal vasculature of the posterior cranial fossa was studied on injected normal anatomical specimens and in angiograms of patients with posterior fossa meningiomas. The correlated results indicate that the dura anterior to the foramen magnum is supplied by meningeal vessels from the carotid siphon, the ascending pharyngeal and middle meningeal arteries. The dura posterior to the foramen magnum is supplied primarily by the occipital artery and secondarily by the vertebral artery.


2021 ◽  
pp. 028418512110558
Author(s):  
Rosalinda Calandrelli ◽  
Fabio Pilato ◽  
Luca Massimi ◽  
Roberta Onesimo ◽  
Gabriella D’Apolito ◽  
...  

Background Most infants and children with achondroplasia show delayed motor skill development; however, some patients may have clinical consequences related to cranio-cervical junction stenosis and compression. Purpose To assess, using brain magnetic resonance imaging (MRI), quantitative variables linked to neuromotor impairment in achondroplasic children. Material and Methods In total, 24 achondroplasic children underwent pediatric neurological assessment and were grouped in two cohorts according to relevant motor skill impairment. Achondroplasic children with (n=12) and without (n=12) motor symptoms were identified, and brain MRI scans were quantitatively evaluated. 3D fast spoiled gradient echo T1-weighted images were used to assess: supratentorial intracranial volumes (SICV); supratentorial intracranial brain volume (SICBV); SICV/SICBV ratio; posterior cranial fossa volume (PCFV); posterior cranial fossa brain volume (PCBFV); PCFV/PCFBV ratio; ventricular and extra-ventricular cerebrospinal fluid (CSF) volumes; foramen magnum (FM) area; and jugular foramina (JF) areas. Results In both groups, SICV/SICBV ratio, supratentorial ventricular and extra-ventricular space volumes were increased while SICBV was increased only in the asymptomatic group ( P < 0.05). PCFV/PCFBV ratio, IV ventricle, infratentorial extra-ventricular spaces volumes were reduced ( P < 0.05) in the symptomatic group while PCFBV was increased only in the asymptomatic group ( P < 0.05). Foramen magnum (FM) area was more reduced in the symptomatic group than the asymptomatic group ( P < 0.05) but no correlation between FM area and ventriculomegaly was found ( P > 0.05). Conclusion Evaluation of the FM area together with infratentorial ventricular and extra-ventricular space volume reduction may be helpful in differentiating patients at risk of developing motor skill impairment. Further investigation is needed to better understand the temporal profile between imaging and motor function in order to propose possible personalized surgical treatment.


Author(s):  
V. V. Ramesh Chandra ◽  
B. C. M. Prasad ◽  
V. Niranjan ◽  
Paradesi Rajesh

Background: There is considerable debate in the surgical management of epidermoid cyst, whether gross total or subtotal resection yields better long term outcomes. We present our institutional experience in evaluating the clinical presentation, diagnosis, and surgical strategy and extent of resection in the management of posterior cranial fossa epidermoid cyst.Methods: A retrospective review of 24 patients diagnosed with posterior cranial fossa epidermoid tumors surgically treated at the institution between January 2010 and July 2019.Results: A total of 24 patients who underwent surgery for intracranial epidermoid lesions were identified. Of these 13 were in the Cerebellopontine angle region, eight were in the fourth ventricle, and three in lateral cerebellar convexity. The mean duration from onset of symptoms to surgery was 1.6 years. Cranial nerve dysfunction was noted in 73% of patients preoperatively, most of them being the CPA epidermoids. Total removal was achieved in 16 patients, near-total resection in 6 patients, and subtotal removal in 2 patients. Three patients developed recurrence radiologically of them only one patient became symptomatic. The mean duration of follow-up was 3.8 years. The content of the tumor was pearly white material in all cases. Complications noted in the present series were not related to the completeness of excision. Mortality was noted in one patient.Conclusions: The present study highlights various precautions to be taken intraoperatively in the prevention of development of aseptic meningitis and concludes that total removal of epidermoids does not result in significantly increased morbidity and mortality and should be the goal of surgical treatment. However, near/subtotal resection of lesions that are densely adherent to neurovascular structures is justified, as there is no significant difference in the rate of recurrence. An endoscope can be used to assess the completeness of surgery.


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