Imaging in Craniofacial Disorders With Special Emphasis on Gradient Echo Black-Bone and Zero Time Echo MRI Sequences.

Context: The well-known effects of ionizing radiation on brain cells have been a major driving force toward the use of non-ionizing methods of imaging in both elective and emergency settings. Pediatric neurosurgery has certainly leveraged on this shift in clinical practice, however patients with craniofacial disorders could not fully benefit from the adoption of magnetic resonance imaging (MRI) because computed tomography (CT) scans still retain superior imaging power on bone tissue. Aims: To explore the knowledge available on the use of MRI as surrogate for CT scan in the assessment of craniosynostosis. Settings and Design: A scoping review was designed to identify landmark studies and ongoing clinical trials exploring the accuracy of MRI-based bone imaging in the preoperative planning of pediatric patients with craniosynostosis. Materials and Methods: A total of 492 records were screened from Pubmed, Ovid Medline, Scopus, and Cochrane Library databases; while 55 records were retrieved from ClinicalTrials.gov register. Only clinical studies revolving around the use of Gradient Echo Black-Bone (BB) and Zero Time Echo (ZTE) MRI sequences for the preoperative planning of pediatric craniosynostosis were retained for inclusion. Results and Conclusions: This review identified only five clinical studies reporting a high accuracy of MRI-based 3D bone reconstruction in 47 pediatric candidates to surgical correction of craniosynostosis. Although promising, limited evidence (Level IV) exist that BB and ZTE MRI could help in the surgical planning for craniosynostosis management. The results of two ongoing randomized clinical trials, which are actively enrolling patients, will hopefully help answering this research question.

Pre-operative imaging and post-operative appearance of standard paediatric neurosurgical approaches: a training guide for neuroradiologists.

A short-cut narrative review was conducted according to the SANRA guidelines to identify studies describing normal and abnormal postoperative radiological features of the most common paediatric neurosurgical procedures. Rather than focusing on the original pathology addressed by neurosurgical means, this review explored three main areas of operative neurosurgery: ventricular access, supratentorial & infratentorial craniotomies, and posterior fossa/craniocervical junction decompression. A total of twenty-three landmark papers were included for review based on their relevance to address the research question and serve as a practical guide for paediatric neuroradiology trainees and fellows. Accurate in text referencing of the ClinicalTrials.gov identifier, and weblink, has also been provided for all trials discussed in the results section. All the above is complemented by relevant iconography meant to describe a wide range of postoperative changes and early complications. Finally, the review is enriched by a discussion touching upon haemostatic agents, intentionally retained foreign bodies and the future of machine learning for neuroradiology reporting. Overall, the information presented in a systematic fashion will not only help trainees and fellows to deepen these topics and expand their knowledge in preparation for written and oral boards, but will also represent a useful resource for everyone including trained neuroradiologists and neurosurgeons themselves.

Chiari 1 malformation and raised intracranial pressure.

BACKGROUND: The pathophysiology of Chiari 1 malformation (CM1) is inextricably related to intracranial pressure (ICP). The characteristic cerebellar tonsil herniation at the foramen magnum may either cause raised ICP by disturbing CSF flow (as observed in idiopathic CM1) or may itself be the effect of raised ICP (as observed in acquired CM1). Distinguishing between these two phenomena, therefore, is of paramount importance in successfully alleviating the symptoms of the condition and preventing serious complications. OBJECTIVES: In this article, we discuss the pathophysiology of raised ICP in CM1 and review the current evidence for its investigation and treatment. We also share our own clinical experience which investigates the utility of ICP monitoring in a series of 26 children with CM1.

Multisuture Craniosynostosis and Papilledema in Pycnodysostosis: A Paradox?

Pycnodysostosis (PYCD) is a rare autosomal-recessive skeletal disorder that typically presents with osteosclerosis of the majority of the postcranial skeleton and osteolysis of the calvarium, manifesting as persistent open cranial fontanelles and widely spaced cranial sutures. Craniosynsostosis in PYCD is a somewhat paradoxical feature, and has only been rarely reported. The authors present a unique case of a 6-year-old girl with PYCD, multisuture craniosynostosis involving the coronal and sagittal sutures, severe obstructive sleep apnoea, and raised intracranial pressure presenting as papilledema. She underwent a frontofacial monobloc distraction advancement which successfully corrected her papilledema and obstructive sleep apnoea.Pycnodysostosis is caused by a loss of function mutation in the CTSK gene that codes for the lysosomal cysteine protease, cathepsin K (CTSK). Loss of CTSK impairs the ability of osteoclasts to degrade bone extracellular matrix. Differences in osteoclast phenotype and extracellular matrix composition between membranous and cartilaginous bone may explain the clinical features of PYCD. Animal model studies suggest that craniosynostosis may arise due to variations in patient genetic background.

Routine radiographs one day after anterior cervical discectomy and fusion are neither necessary nor cost-effective.

OBJECTIVES: Anterior cervical discectomy and fusion (ACDF) is a common operative treatment of compressive pathology of the cervical spinal cord, when caused by one or more degenerated intervertebral discs or related osteophytes. In addition to intra-operative radiographs to confirm spinal level before discectomy and implant position after insertion, traditional practice is to obtain post-operative antero-posterior and lateral plain radiographs (XR) before hospital discharge, despite a paucity of evidence supporting their benefit to patient care. Minimising unnecessary radiation to radiosensitive neck structures is desirable, and furthermore, with increasing financial pressure on healthcare resources, routine investigations should be clinically justified and evidence-based. We aim to compare the utility of routine post-operative cervical spine X-rays following ACDF. METHODS: We compare two groups of consecutive patients undergoing ACDF in a single UK neurosurgical centre. The first group (n = 109) received routine post-operative XR imaging, and the second group (n = 113) received radiographs only when clinically indicated. RESULTS: There were no differences in post-operative complication rates (4.6% vs. 5.3%), or requirement for further imaging or of further operative intervention (1.8% vs. 0.9%). The group that did not have routine post-operative radiographs had a significantly shorter stay in hospital (median two days vs. three days). There were no patients in either group where post-operative XR changed clinical management and mandated revision surgery or further imaging. All cases requiring surgery or further imaging were identified by clinical deterioration. CONCLUSIONS: We suggest that the practice of obtaining routine radiographs of the cervical spine following ACDF should be abandoned, unless there is a clear clinical indication.

The incidence of raised intracranial pressure in nonsyndromic sagittal craniosynostosis following primary surgery.

OBJECT Raised intracranial pressure (ICP) is recognized to occur in patients with nonsyndromic isolated sagittal craniosynostosis (SC) prior to surgery. However, the incidence of raised ICP following primary surgery is rarely reported and there appears to be a widely held assumption that corrective surgery for SC prevents the later development of intracranial hypertension. This study reports the incidence of postoperative raised ICP in a large cohort of patients with SC treated by 1 of 2 surgical procedures in a single craniofacial unit. METHODS A retrospective review was performed of all patients with SC who underwent either a modified strip craniectomy (MSC) or calvarial remodeling (CR) procedure under the care of the Oxford Craniofacial Unit between 1995 and 2010 and who were followed up for more than 2 years. The influence of patient age at surgery, year of surgery, sex, procedure type, and the presence of raised ICP preoperatively were analyzed. RESULTS Two hundred seventeen children had primary surgery for SC and were followed up for a mean of 86 months. The overall rate of raised ICP following surgery was 6.9%, occurring at a mean of 51 months after the primary surgical procedure. Raised ICP was significantly more common in those patients treated by MSC (13 of 89 patients, 14.6%) than CR (2 of 128 patients, 1.6%). Also, raised ICP was more common in patients under 1 year of age, the majority of whom were treated by MCS. No other factor was found to have a significant effect. CONCLUSIONS Postoperative raised ICP was found in more than 1 in 20 children treated for nonsyndromic SC in this series. It was significantly influenced by the primary surgical procedure and age at primary surgery. Careful long-term follow-up is essential if children who develop raised ICP following surgery are not to be overlooked.

Long-term morphological outcomes in nonsyndromic sagittal craniosynostosis: a comparison of 2 techniques.

Correction of scaphocephaly is one of the principle goals of surgery in sagittal craniosynostosis. Reported relapse in head shape after surgery and continued head growth into late adolescence underscores the need for long-term outcomes to be considered when comparing between different surgical approaches in this condition; yet there are relatively few reports of results to 5 years and beyond in the literature. Therefore, a retrospective review was performed of the anthropometric data of 224 patients with sagittal craniosynostosis who underwent primary surgery between 1994 and 2012. During this period, patients underwent either a modified strip craniectomy (MSC) or calvarial remodeling (CR) procedure. Sixty-two patients were treated by MSC and followed up for a mean of 44 months. One hundred sixty-two patients had CR, with follow-up for a mean of 45 months. Overall, 90 patients were seen up to 5 years, and 47 patients to 9 years or more after surgery. The cephalic index (CI) of MSC-treated patients improved from a mean of 67.0 to 72.7, with 31% achieving a CI greater than 75 at one year. Calvarial remodeling was significantly more effective at correcting the scaphocephalic deformity. Patients treated with CR improved from a mean CI of 66.7 to 76.1. Sixty-two percent of the patients achieved a CI greater than 75. In both groups, outcomes were stable throughout follow-up with no significant relapse up to 14 years after surgery.

A pediatric chronic subdural hematoma: More than meets the eye.

We present an unusual case of a 13-year-old child who following minor head injury presented with what appeared to be a thin chronic subdural hematoma on plain computed tomography imaging. The child was found to have an underlying arachnoid cyst. Intra- and extra-cystic bleeding had occurred simultaneously causing an isodense cyst with an accompanying subdural collection. This radiographically occult pathology should be excluded using magnetic resonance imaging in any child presenting with a subdural collection.

The preoperative incidence of raised intracranial pressure in nonsyndromic sagittal craniosynostosis is underestimated in the literature.

OBJECT: The presence of raised intracranial pressure (ICP) in untreated nonsyndromic, isolated sagittal craniosynostosis (SC) is an important functional indication for surgery. METHODS: A retrospective review was performed of all 284 patients presenting with SC to the Oxford Craniofacial Unit between 1995 and 2010. RESULTS: Intraparenchymal ICP monitoring was performed in 39 children following a standard unit protocol. Monitoring of ICP was offered for all patients in whom nonoperative management was considered on the basis of minimal deformity or in cases in which parents were reluctant to agree to corrective surgery. These patients presented at an older age than the rest of the cohort (mean age 56 months), with marked scaphocephaly (16/39, 41%), mild scaphocephaly (11, 28%), or no scaphocephalic deformity (12, 31%). Raised ICP was found in 17 (44%) patients, with no significant difference in its incidence among the 3 different deformity types. Raised ICP was not predicted by the presence of symptoms of ICP or developmental delay or by ophthalmological or radiological findings. CONCLUSIONS: The incidence of raised ICP in SC reported here is greater than that previously published in the literature. The lack of a reliable noninvasive method to identify individuals with elevated ICP in SC mandates consideration of intraparenchymal ICP monitoring in all patients for whom nonoperative management is contemplated.

Lessons learned in posterior cranial vault distraction.

INTRODUCTION: Posterior distraction (PD) is rapidly emerging as an important technique to increase the intracranial volume and correct calvarial morphology in patients with severe brachycephaly or turribrachycephaly. METHODS: A retrospective review was performed of all 31 patients who underwent PD at the Oxford Craniofacial Unit between 2007 and 2012. RESULTS: Twenty-three patients (74.2%) underwent PD as a primary procedure at a median age of 8 months. Eight patients (25.8%) had PD as a secondary transcranial procedure at a median age of 48 months. Full distraction to 20 mm was achieved in 28 patients (90.3%). Of these, all but 1 demonstrated a significant improvement in morphology, with a resolution of the symptoms and signs of raised intracranial pressure in all proven to have it preoperatively. Unanticipated events occurred in 61.3% of patients, with 19.4% undergoing one or more unplanned procedures. Wound infection (29.0%) and tissue necrosis (22.6%) were the commonest. Cerebrospinal fluid leaks were rarer (6.5%) but prevented full distraction. Nine patients (29.0%) had a consolidation period of less than 30 days without experiencing relapse. In 11 patients who had a later fronto-orbital advancement and remodeling, wound closure was tight, resulting in dehiscence in 3 cases (27.3%). CONCLUSIONS: Posterior distraction is an effective procedure in the management of severe brachycephaly or turribrachycephaly but has associated risks. Our protocol has evolved with experience to favor a reduced latency period and consolidation phase and the use of 2 distractor devices.

Recurrent subdural hygromas after foramen magnum decompression for Chiari Type I malformation.

A paediatric case of foramen magnum decompression for Chiari Type I malformation complicated by recurrent subdural hygromas (SH) and raised intracranial pressure without ventriculomegaly is described. SH pathogenesis is discussed, with consideration given to arachnoid fenestration. We summarise possibilities for treatment and avoidance of this unusual consequence of foramen magnum decompression.

Everything to gain: Sir Hugh Cairns' treatment of central nervous system infection at Oxford and abroad.

Antibiotics have revolutionized survival from central nervous system (CNS) infections. Sixty years after the death of Sir Hugh Cairns, we present archive material of historical interest from the Radcliffe Infirmary in Oxford from the time of his first trials of penicillin for CNS infection. We discuss Cairns' important wartime and subsequent contributions to antibiosis in CNS infection and include drawings by Audrey Arnott illustrating the surgical techniques used to treat abscesses at the time.