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Object: Hindbrain herniation syndrome, or Chiari malformation Type I (CM-I), occurs frequently with craniovertebral junction (CVJ) abnormalities when there is reduction in the posterior fossa volume. Syringomyelia is often present. Posterior fossa dorsal decompression (PFDD) is typically performed but has adverse results when ventral bone abnormality exists. This paper presents the results of a prospective study on CVJ abnormalities in patients with CM-I and syringomyelia., Methods: Between 1984 and 2008 (the MR imaging era), 298 patients with CVJ abnormalities and CM-I underwent ventral cervicomedullary decompression. Eighty-four patients had associated syringomyelia (15 with secondary invagination and 69 with primary basilar invagination, os odontoideum, or malunion of fractures). Of these 84 patients with CVJ abnormalities, CM-I, and syringomyelia, 46 had previously undergone PFDD, and 28 had previously undergone PFDD combined with fusion procedures or shunt placements. Of the 84 patients, a cervicothoracic syrinx was observed in 57, thoracic syrinx in 14, and holocord syrinx in 13. Studies included CT, MR imaging, and cine flow studies. All 298 patients who underwent ventral CVJ decompression had irreducible or partially reducible pathology. All 84 with syringomyelia showed brainstem dysfunction, lower cranial nerve symptoms, or myelopathy., Results: Brainstem signs improved in 66 of the 84 patients, myelopathy improved in 58, and syringomyelia regressed in 64., Conclusions: Neurological improvement and syringomyelia resolution can occur using only ventral cervicomedullary junction decompression in patients with basilar invagination and basilar impression. This is likely due to the relief of neural encroachment and reestablishment of CSF pathways.

Object: There is scant literature regarding the long-term outcome in patients with cranial vault encephaloceles, and what literature there is may underestimate long-term deficits. The goal of this study was to address this lack of information., Methods: The authors performed a retrospective chart review of cranial vault encephaloceles performed at our institution between 1989 and 2003. Fifty-two total patients were identified and 44 of these cases were reviewed. Additionally, 34 of the 44 patients were contacted and given an outcome survey (Hydrocephalus Outcome Questionnarie [HOQ]) to evaluate physical, emotional, cognitive, and overall health outcomes., Results: The mean age for patients in this cohort was 9.6 years (range 4-17 years) and the mean follow-up time was 9.2 years. There was an equal sex distribution and there were no deaths. Hydrocephalus was found in 60% of occipital and 14% of frontal encephaloceles, and epilepsy was confirmed in 17% of occipital and 7% of frontal lesions. Outcome assessments performed using the HOQ showed that 50% of the patients with occipital encephaloceles had overall HOQ health scores of 0.5 or less and 55% had HOQ cognitive scores of 0.3 or less, compared with 0% of patients in both categories who had frontal encephaloceles. It was also found that the presence of hydrocephalus and epilepsy independently and significantly lowered the overall health scores., Conclusions: Occipital encephaloceles carry a worse prognosis than frontal encephaloceles, with higher rates of hydrocephalus and seizure. Based on this study, the presence of hydrocephalus and epilepsy are significant additive adverse prognostic factors. Approximately half of the patients with occipital encephaloceles will be severely debilitated and will probably be unable to live and function independently in society. These data may be useful to clinicians in counseling patients and predicting long-term outcome following repair of cranial vault encephaloceles.

Occipital dermal sinuses (ODSs) are congenital lesions located in the midline and characterized by a cutaneous pit or dimple. The intracranial extension as well as the associated symptoms are variable. To date, a familial occurrence of these lesions has not been reported. In this paper the authors report on a 2-year-old boy with an ODS and intracranial hypertension. The boy's mother had a similar lesion but did not have any complaints. Following their experience with this case and a literature review, the authors suggest that there may be a genetic basis in certain instances of ODS.

Basicranial diastematomyelia is an extremely rare congenital disorder. A review of the literature indicates only one reported case of basicranial diastematomyelia in which an osseous peg divided the brainstem in two. The authors present the first reported case of basicranial diplomyelia split by a fibrous band and correlate its pathogenesis with that of split cord malformation (SCM). The patient described in the present report had a fibrous stalk dividing the brainstem, and therefore the condition was categorized as a diplomyelia, or SCM Type II. Because the occipital dermatomes behave similarly to the spinal dermatomes early in development, they may be subject to the same embryonic error that results in SCM. The authors propose that the mechanism leading to SCM is the same as that found in basicranial split malformations and that the theory explaining it be modified to include the posterior fossa.

The coexistence of three cranial meningoceles in a single patient is an extremely rare event. Multiple cranial meningoceles have not been reported in the literature. The rare case of a newborn with three distinct occipital meningoceles, of which one was rudimentary, is presented. Diagnostic tools and treatment options are also reviewed.

The authors of this brief case report describe a previously unreported developmental variant of the craniovertebral junction. A 10-year-old girl who presented with cervical myelopathy was found to have cervicomedullary compression by hypertrophic occipital condyles. Decompression was achieved via a midline dorsal approach with no complications. The embryology of this area is briefly reviewed to attempt to explain the origin of this anomaly.

Object: Occipital encephaloceles are relatively frequently encountered. Many investigators have addressed the embryogenesis of these formations, but the dural system has never before been studied. In this retrospective analysis the authors sought to gain a better understanding of the origins of these defects., Methods: The charts and radiological examinations, especially the magnetic resonance venography studies, were reviewed in seven patients. In six patients the straight sinus was absent. Drainage of the galenic system took place through a sinus within the falx, also known as a falcine sinus. The tentorium was not seen in five patients., Conclusions: The combination of an absent straight sinus and dysplastic tentorium is no coincidence: both develop within the same mesenchyme in the mesencephalic flexure. Distortion of the mesenchyme by a neural tube defect, causing an occipital encephalocele, will lead not only to disorders of the tentorium but also of the straight sinus.

Iniencephaly is a rare congenital anomaly characterized by spina bifida of the cervical vertebrae, fixed retroflexion of the head on the cervical spine, and occipital bone defect. There are only five reports of surviving patients with iniencephaly. The authors report the case of a newborn who presented with iniencephaly and an encephalocele that were surgically treated in our service. Neurological examination of the patient yielded normal results except for a moderate psychomotor retardation. The neuroradiological and surgical findings of the case suggested that the trigger of the anomaly was the occipital bone defect and rachischisis of the posterior vertebral arches.

Object: The literature on occipital plagiocephaly (OP) was critically reviewed to determine the feasibility of establishing treatment recommendations., Methods: Using standard computerized search techniques, medical literature databases containing peer-review articles dating from 1966 were queried for key words related to OP. The titles of all articles were scanned for relevance, and copies of potentially relevant articles published in English were reviewed. Articles in which treatment was discussed were categorized according to their weight of evidence as Class I (prospective randomized controlled trials), Class II (clinical studies in which data are collected prospectively or retrospective analyses based on clearly reliable data), and Class III (most studies based on retrospectively collected data) to evaluate their contribution to developing a consensus on the treatment of OP. Of the 4308 articles identified, all but 89 were excluded. Based on the review of these articles, the actual incidence of OP is unknown, and no population-based studies of its incidence or prevalence exist. The reported incidence of lambdoid craniosynostosis ranges from 3 to 20% with differences in diagnostic criteria accounting for the variability. With the possible exception of a lambdoid suture that is replaced by a dense ridge of bone, no other diagnostic criteria have been agreed on. There were no Class I studies and only one Class II study provided comparisons of outcomes in more than one treatment group with outcomes in an untreated group. Recommended treatment options included observation only, mechanical interventions, and a variety of surgical techniques., Conclusions: Controlled clinical trials are needed before any form of intervention can be recommended for the treatment of OP. If surgery, which is expensive and potentially dangerous, is to continue to play a role in the management of this condition, efforts should be made to determine if patients with untreated OP have suffered from lack of treatment.

Management of neonates with nonsynostotic occipital plagiocephaly has been controversial, and there has been a lack of uniformity concerning its treatment. Patients with nonsynostotic occipital plagiocephaly have been treated surgically or with cranial remodeling orthotic devices and have shown improvement in asymmetry. The cost of orthotic treatment has risen, and its validity has been contested by many third-party insurance payers. The effectiveness of orthotic treatment has not been adequately compared to the natural history of nonsynostotic occipital plagiocephaly. A nonsurgical, nonorthotic treatment study was initiated in June 1995 at Phoenix Children's Hospital. All new patients referred with a diagnosis of nonsynostotic occipital plagiocephaly were categorized into two groups: those with mild-to-moderate asymmetry and those with moderate-to-severe asymmetry. Categories were determined by cephalic measurements. The patients with moderate-to-severe asymmetry were offered orthotic treatment with a cranial remodeling band. Those patients with mild-to-moderate asymmetry were treated with physiotherapy, repositioning of the head, and repeated notation of cephalic measurements without orthotic devices or surgery. Seventy-two neonates, seen consecutively, with mild-to-moderate, nonsynostotic occipital plagiocephaly were evaluated by noting cephalic measurements. The parents of six of these patients elected treatment with a cranial remodeling band and results in these patients were excluded from our data. The remaining 66, treated without orthotic devices, showed improvement in average cranial vault asymmetry (CVA) from 9.2 to 4.7 mm over an average treatment period of 4.5 months that commenced when the average age of the patient was 6.4 months. A comparison of the present data with data published in 1994 for neonates treated with a headband indicates that neonates with mild-to-moderate asymmetry who are treated aggressively with physiotherapy and repositioning have similar improvement in CVA.