OBJECTIVE: The frontal sinus is frequently a troublesome anatomical obstacle to gain access to the medial anterior cranial base. Surgical approaches to and through the frontal sinus using osteoplastic frontal sinusotomy provide significant advantages to the treatment of lesions of the medial anterior cranial base in addition to the frontal sinus itself. However, appropriate management is necessary to avoid postoperative complications such as cerebrospinal fluid leakage, infection, mucocele formation, and deformity of the forehead. METHODS: The advantages and shortcomings of the approach along with the surgical technique are reported based on our clinical experience with pertinent literature review. The approach using the osteoplastic frontal sinusotomy was applied to two cases of osteoma in the frontal sinus, seven cases of craniofacial tumors, a case of chordoma in the sphenoid and clivus, and two cases of intradural lesions in the anterior cranial fossa. The frontal sinus was managed in such a way as to prevent the postoperative complications. RESULTS: All patients underwent gross total resection of the tumors. With a mean follow-up of 26 months, there were no postoperative complications related to frontal sinus violation. CONCLUSION: The neurosurgical approaches via the frontal sinus using osteoplastic frontal sinusotomy are versatile for various lesions of the anterior cranial base in patients with large frontal sinuses. In situations that the frontal sinus have to be violated to approach medial anterior cranial base, the osteoplastic frontal sinusotomy provides such advantages as optimal frontal sinus control to prevent postoperative complications; increases viewing angle with superior trajectory from nasofrontal suture; lower incidence of pnemocephalus due to minimal dural exposure; and excellent cosmesis without frontal burr holes.
Cerebrospinal Fluid ; Chordoma ; Congenital Abnormalities ; Cranial Fossa, Anterior ; Cranial Fossa, Posterior ; Follow-Up Studies ; Forehead ; Frontal Sinus* ; Humans ; Incidence ; Mucocele ; Osteoma ; Postoperative Complications ; Skull Base ; Sutures

OBJECTIVE: In this study, we aimed to investigate the underlying ethiological factors in chiari malformation (CM) type-I (CMI) via performing volumetric and morphometric length-angle measurements. METHODS: A total of 66 individuals [33 patients (20-65 years) with CMI and 33 control subjects] were included in this study. In sagittal MR images, tonsillar herniation length and concurrent anomalies were evaluated. Supratentorial, infratentorial, and total intracranial volumes were measured using Cavalieri method. Various cranial distances and angles were used to evaluate the platybasia and posterior cranial fossa (PCF) development. RESULTS: Tonsillar herniation length was measured 9.09+/-3.39 mm below foramen magnum in CM group. Tonsillar herniation/concurrent syringomyelia, concavity/defect of clivus, herniation of bulbus and fourth ventricle, basilar invagination and craniovertebral junction abnormality rates were 30.3, 27, 18, 2, 3, and 3 percent, respectively. Absence of cisterna magna was encountered in 87.9% of the patients. Total, IT and ST volumes and distance between Chamberlain line and tip of dens axis, Klaus index, clivus length, distance between internal occipital protuberance and opisthion were significantly decreased in patient group. Also in patient group, it was found that Welcher basal angle/Boogard angle increased and tentorial slope angle decreased. CONCLUSION: Mean cranial volume and length-angle measurement values significantly decreased and there was a congenital abnormality association in nearly 81.5 percent of the CM cases. As a result, it was concluded that CM ethiology can be attributed to multifactorial causes. Moreover, congenital defects can also give rise to this condition.
Cisterna Magna ; Congenital Abnormalities ; Cranial Fossa, Posterior ; Encephalocele ; Foramen Magnum ; Fourth Ventricle ; Humans ; Magnetic Resonance Imaging* ; Odontoid Process ; Platybasia ; Syringomyelia

PURPOSE: Joubert syndrome presents neonatal respiratory abnormalities and other clinical manifestations. Pathologically the patients show hypoplasia or agenesis of cerebellar vermis and other intracranial anomalies. Our purpose is to evaluate the clinical manifestations and MR findings of Joubert syndrome. MATERIALS AND METHODS: Among the patients presenting with clinical stigmata of Joubert syndrome and agenesis of vermis on MR imaging, eight patients who did not satisfied the criteria of Dandy-Walker malformation, tectocerebellar dysraphia and rhombencephalosynapsis were selected. MR findings and clinical manifestation were analyzed. RESULTS: On MR imaging, agenesis of the cerebellar vermis (all cases), hypoplasia of the cerebellar peduncle (6cases), fourth ventricular contour deformity(6cases), tentorial elevation (4cases), deformity of the lateral ventricles (4cases), dysgenesis of the straight sinus (3cases) were demonstrated. Other findings were abnormalities of corpus callosum (3cases), falx anomalies (3 cases), occipital encephalomeningocele (2 cases) and fluid collection in posterior cranial fossa (2cases). Clinical manifestations were developmental delay (5cases), abnormal eyeball movement (3cases), hypotonia (2 cases), neonatal rerspiratoy abnormality (2cases), etc. CONCLUSION: Joubert syndrome showed various clinical manifestations and intracranial anomalies. MR imaging is an useful modality in detection of the cerebellar vermian agenesis and other anomalies of the patients.
Christianity ; Congenital Abnormalities ; Corpus Callosum ; Cranial Fossa, Posterior ; Dandy-Walker Syndrome ; Humans ; Lateral Ventricles ; Magnetic Resonance Imaging* ; Muscle Hypotonia

OBJECTIVE: To examine the normal range of the width of posterior cranial fossa (WPCF) in the second and third trimester by ultrasonography, and to investigate its relationship with fetal congenital and chromosome abnormality. METHODS: WPCF of 2484 fetus (gestational age from 14 to 41 weeks) was measured by ultrasonograph routinely, and the infants were followed up. RESULTS: In 2848 fetus, 2772 were normal and 76 were abnormal. WPCF increased before 32 weeks, decreased after 33 weeks, the largest value of WPCF was 13.4 mm. The occurrence rate of WPCF> or =8 mm in normal fetus was 8.84%, and that in abnormal fetus was 17.46%. Most fetuses with chromosome abnormality had normal WPCF in the second trimester, but some fetuses with remarkable broadening in the late stage. Some abnormal fetuses (such as water head, Dandy-Walker's syndrome etc) showed significant extension of WPCF. CONCLUSION WPCF increases before 32 weeks, decreases after 33 weeks;and can be easily measured during 29 - 32 weeks. WPCF of some fetus with chromosome abnormality or with congenital abnormality is remarkably broadened in the late stage. The fetus of WPCF> or =10 mm should be followed up closely, and antenatal diagnosis should be done if WPCF is more than 14 mm.
Adult ; Cranial Fossa, Posterior ; abnormalities ; diagnostic imaging ; Female ; Humans ; Pregnancy ; Pregnancy Trimester, Second ; Pregnancy Trimester, Third ; Ultrasonography, Prenatal

Though several pathogenetic theories concerning the frequent association of Chiari malformation and hydrocephalus with myeloschisis have been suggested, none of them explains all the aspects of the disorder. To investigate whether myeloschisis is the direct cause of Chiari malformation and hydrocephalus or these conditions are the results of another basic event, we observed the morphological changes of the posterior cranial fossa and its components in the chick embryos with surgically induced myeloschisis. To make myeloschistic lesions, we opened the neural tube for a length of 9-11 somites in Hamburger and Hamilton stage 16-19 chick embryos. They were divided into cervicothoracic (C-T) and lumbosacral(L-S) groups according to the area of incision. The embryos were re-incubated until postoperative day 11. In the control group, embryos were incubated with the eggshell window open as their experimental counterparts. The survival rates of each group were as follows; 11% (9 survivors/85 operated embryos), 8% (7/83), and 17% (10/60) in the C-T, L-S and control groups, respectively. Myeloschisis positive rates were 100% in the operated groups and 0% in the control group. The heads of embryos were sectioned along the sagittal plane to observe the morphological changes in the posterior cranial fossa and its components. Of the survivors, five in the C-T group, two in the L-S group and six in the control group were available for light microscopic inspection. In the majority of embryos with myeloschisis, without difference between the C-T and L-S groups, the fourth ventricles were smaller than those of the control group and the subarachnoid spaces in the posterior cranial fossa were also narrower. In embryos with severe changes, the cerebellum displaced downward comparing with that of the control embryos. No evidence of hydrocephalus was present Though not always typical, morphological changes similar to Chiari malformation were observed in chick embryos with surgically induced myeloschisis. It suggests a strong direct causal relationship between the two conditions and supports the theories of derangements in cerebrospinal fluid dynamics rather than those of primary mesenchymal or neural origin as a pathogenetic mechanism of Chiari malformation.
Animal ; Brain/*abnormalities ; Chick Embryo ; Cranial Fossa, Posterior/abnormalities ; Disease Models, Animal ; Hydrocephalus/etiology ; Spinal Cord/*abnormalities ; Subarachnoid Space/abnormalities ; Support, Non-U.S. Gov't

Though several pathogenetic theories concerning the frequent association of Chiari malformation and hydrocephalus with myeloschisis have been suggested, none of them explains all the aspects of the disorder. To investigate whether myeloschisis is the direct cause of Chiari malformation and hydrocephalus or these conditions are the results of another basic event, we observed the morphological changes of the posterior cranial fossa and its components in the chick embryos with surgically induced myeloschisis. To make myeloschistic lesions, we opened the neural tube for a length of 9-11 somites in Hamburger and Hamilton stage 16-19 chick embryos. They were divided into cervicothoracic (C-T) and lumbosacral(L-S) groups according to the area of incision. The embryos were re-incubated until postoperative day 11. In the control group, embryos were incubated with the eggshell window open as their experimental counterparts. The survival rates of each group were as follows; 11% (9 survivors/85 operated embryos), 8% (7/83), and 17% (10/60) in the C-T, L-S and control groups, respectively. Myeloschisis positive rates were 100% in the operated groups and 0% in the control group. The heads of embryos were sectioned along the sagittal plane to observe the morphological changes in the posterior cranial fossa and its components. Of the survivors, five in the C-T group, two in the L-S group and six in the control group were available for light microscopic inspection. In the majority of embryos with myeloschisis, without difference between the C-T and L-S groups, the fourth ventricles were smaller than those of the control group and the subarachnoid spaces in the posterior cranial fossa were also narrower. In embryos with severe changes, the cerebellum displaced downward comparing with that of the control embryos. No evidence of hydrocephalus was present Though not always typical, morphological changes similar to Chiari malformation were observed in chick embryos with surgically induced myeloschisis. It suggests a strong direct causal relationship between the two conditions and supports the theories of derangements in cerebrospinal fluid dynamics rather than those of primary mesenchymal or neural origin as a pathogenetic mechanism of Chiari malformation.
Animal ; Brain/*abnormalities ; Chick Embryo ; Cranial Fossa, Posterior/abnormalities ; Disease Models, Animal ; Hydrocephalus/etiology ; Spinal Cord/*abnormalities ; Subarachnoid Space/abnormalities ; Support, Non-U.S. Gov't

BACKGROUND: Hemifacial spasm (HS) has been attributed frequently to vascular compression of facial nerve root exit zone from brainstem. A recent brain CT scan study showed that patients with HS had narrower posterior fossa than normal controls. However, cause relationship between narrowed posterior fossa and vascular tortuosity is unknown. METHODS: In 25 patients with HS and 29 controls, using temporal bone MRI, we measured petrous angle (PA) and pons diameter index (PDI) to define correlation between severity of posterior fossa narrowing and compression to brainstem. We compared severity of narrowing of posterior fossa between patients with and without tortuous arteries in posterior fossa. We also compared degree of narrowing of posterior fossa and clinical severity of HS. RESULTS: The mean (+/-standard deviation) of PA of 24 patients with HS (115.5 +/-6.0 degree) was significantly smaller than that of controls ( 118.6 +/- 4.8 degree). The mean (+/-standard deviation) of PDI of patients with HS (82.5 +/-4.7%) was significantly greater than that of controls (77.3 +/-3.7%). However, there was no correlation between PA and PDI in patients with HS. There was no correlation between degree of narrowing of posterior fossa and clinical severity of HS. CONCLUSIONS: Patients with HS have narrower posterior fossa as compared with controls. However, narrow posterior fossa does not seem to be a single important factor causing deformity of brainstem or tortuous arteries in posterior fossa.
Arteries ; Brain ; Brain Stem ; Congenital Abnormalities ; Cranial Fossa, Posterior ; Facial Nerve ; Hemifacial Spasm* ; Humans ; Magnetic Resonance Imaging* ; Pons ; Temporal Bone* ; Tomography, X-Ray Computed

Here we report a single-stage operation we performed on a patient with a large schwannoma that extended from the lower clivus to the cervico-thoracic junction caudally. A number of authors have previously performed multilevel laminectomy to remove giant schwannomas that extend for considerable length. This technique has caused cervical instability such as kyphosis or gooseneck deformity on several occasions. We removed the tumor with a left lateral suboccipital craniectomy with laminectomy only at C1 and without any subsequent surgery-related neurologic deficits. However, this technique requires meticulous preoperative evaluation on existence of Cerebrospinal fluid (CSF) cleft between the tumor and spinal cord on magnetic resonance imaging, of tumor origin located at the upper cervical root, and of detachment of tumor from the origin site.
Cerebrospinal Fluid ; Congenital Abnormalities ; Cranial Fossa, Posterior ; Humans ; Kyphosis ; Laminectomy* ; Laminoplasty ; Magnetic Resonance Imaging ; Neurilemmoma* ; Neurologic Manifestations ; Spinal Cord ; Spinal Cord Neoplasms

OBJECTIVE: The objective of this study was to investigate changes in the posterior cranial fossa in patients with symptomatic Chiari malformation type I (CMI) compared to a control group. METHODS: We retrospectively reviewed clinical and radiological data from 12 symptomatic patients with CMI and 24 healthy control subjects. The structures of the brain and skull base were investigated using magnetic resonance imaging. RESULTS: The length of the clivus had significantly decreased in the CMI group than in the control group (p=0.000). The angle between the clivus and the McRae line (p<0.024), as the angle between the supraocciput and the McRae line (p<0.021), and the angle between the tentorium and a line connecting the internal occipital protuberance to the opisthion (p<0.009) were significantly larger in the CMI group than in the control group. The mean vertical length of the cerebellar hemisphere (p<0.003) and the mean length of the coronal and sagittal superoinferior aspects of the cerebellum (p<0.05) were longer in the CMI group than in the control group, while the mean length of the axial anteroposterior aspect of the cerebellum (p<0.001) was significantly shorter in the CMI group relative to control subjects. CONCLUSION: We elucidate the transformation of the posterior cranial fossa into the narrow funnel shape. The sufficient cephalocaudal extension of the craniectomy of the posterior cranial fossa has more decompression effect than other type extension of the craniectomy in CMI patients.
Arnold-Chiari Malformation ; Brain ; Cerebellum ; Congenital Abnormalities ; Cranial Fossa, Posterior* ; Decompression ; Decompressive Craniectomy ; Embryology ; Humans ; Magnetic Resonance Imaging ; Retrospective Studies ; Skull Base