Craniocephalic disproportion with increased intracranial pressure and brain herniation: a new clinical syndrome in anemic patients: report of two cases

[Shunt-induced craniosynostosis: topicality of the problem, choice of the approach, and features of surgical treatment]

RATIONALE

Shunt-induced craniosynostosis is one of the late complications of CSF shunting surgery, which affects the patient's condition, clinical picture, and treatment approach.

OBJECTIVE

to evaluate the prevalence rate and clinical significance of this disease, define the indications for surgery, and choose the optimal surgical approach.

MATERIAL AND METHODS

The study included 59 children with shunt system dysfunction, aged 1 to 14 years, who were treated at the Department in the period from 2014 to 2016. The inclusion criteria were as follows: 1) age at the time of examination is older than 1 year; 2) implantation of a shunt system in the first 12 months of life. The state of cranial sutures was assessed using three-dimensional reconstruction of patient's computerized tomography images. Images obtained before or in the first months after primary implantation of a shunt system were used to exclude cases of primary craniosynostosis.

RESULTS

Premature synostosis of the cranial sutures was detected in 27 (46%) cases. Of these, 3 (11%) patients with clinical symptoms of increased intracranial pressure and radiographic signs of craniocerebral disproportion underwent cranial vault remodeling surgery: two biparietal craniotomies and one fronto-parieto-occipital reconstruction. In two cases, simultaneous replacement of a valve with a programmable one was performed. There were no complications after reconstructive surgery.

CONCLUSION

Shunt-associated craniosynostosis is one of the late complications of CSF shunting surgery. However, its presence is not an indication for surgery and should not be a reason for surgical aggression. Surgery for increasing the intracranial volume is indicated only for secondary craniosynostosis combined with signs of craniocerebral disproportion. In these cases, reconstructive surgery is an effective treatment option for improving the patient's condition.

Upward Translation of Cerebellar Tonsils following Surgical Expansion of Supratentorial Cranial Vault: A Unified Biomechanical Explanation of Chiari Type I

Cerebellar tonsils moved significantly upward in 3 patients with Chiari type I who underwent supratentorial cranial vault expansion to alleviate intracranial pressure related to multisutural craniosynostosis. The Chiari type I deformities in these patients were the biomechanical consequence of posterior fossa-cerebellar disproportion caused by supratentorial craniocerebral disproportion secondary to multisutural craniosynostosis. The authors postulate that all cases of Chiari type I deformity share the sine qua non feature of posterior fossa-cerebellar disproportion.

Craniocerebral disproportion: a topical review and proposal toward a new definition, diagnosis, and treatment protocol

INTRODUCTION

At some point in their lives, patients previously shunted for hydrocephalus may experience chronic, debilitating headaches, despite the fact that their shunts are functioning properly. Previously published reports have suggested that a subset of these patients may be suffering from an iatrogenic craniocerebral disproportion (CCD) and, therefore, may benefit from procedures that expand the available intracranial space. A unified definition of this disorder, however, is lacking.

DISCUSSION

Here, the authors chart the history (including historical terminology) of CCD, review its incidence, describe its signs, symptoms, and associated radiologic findings, and expound upon its pathophysiology. Next, a concise clinical definition of CCD based on the temporal correlation of headaches with the appearance of plateau waves on intracranial pressure (ICP) monitoring is proposed. The authors conclude with a discussion of the various therapeutic strategies employed previously to treat this disorder and present their individualized treatment strategy based upon the simultaneous utilization of ICP monitors and gradual external cranial vault expansion.

What differences exist in the appropriate treatment of congenital versus acquired adult Chiari type I malformation?

Chiari type I malformation is found in 1 out of 20 magnetic resonance imaging (MRI) studies. Isolated tonsillar herniation is of limited utility and should be considered within the clinical context because these patients can be asymptomatic. Cine MRI showing compression of the cerebrospinal fluid (CSF) spaces in the foramen magnum area is a crucial technique for making treatment decisions. Congenital malformation is thought to be due to a volumetric small posterior fossa. The most common symptom in these patients is cough headache. Posterior fossa reconstruction is mandatory in patients with progressive symptoms/signs, hydrocephalus, or syringomyelia, but not in patients who are asymptomatic or those with stable and tolerable symptoms. Acquired tonsillar descent can be secondary to a variety of disorders conditioning disproportion between the volume of the cranial cavity and that of the intracranial contents, or to CSF hypovolemia, which is the most common cause for acquired herniation. CSF hypovolemia can be spontaneous or secondary to CSF removal. Treatment of acquired tonsillar herniation depends on the responsible etiology.

Chiari malformation associated with craniosynostosis

OBJECT

Chiari malformation (CM) Type I is frequently associated with craniosynostosis. Optimal management of CM in patients with craniosynostosis is not well-established. The goal of this study was to report on a series of pediatric patients with both craniosynostosis and CM and discuss their management.

METHODS

The authors searched the medical records of 383 consecutive patients treated for craniosynostosis at a single institution over a 15-year period to identify those with CM. They recorded demographic data as well as surgical treatment and outcomes for these patients. When MR imaging was performed, cerebellar tonsillar descent was recorded and any other associated findings, such as hydrocephalus or spinal syringes, were noted.

RESULTS

A total of 29 patients with both CM and craniosynostosis were identified. Of these cases, 28% had associated occipital venous abnormalities, 45% were syndromic, and 52% also had hydrocephalus. Chiari malformation was more likely to be present in those patients with isolated lambdoid synostosis (55%), multisuture synostosis (35%), and pansynostosis (80%), compared with patients with coronal synostosis (6%) or sagittal synostosis (3%). All patients underwent surgical repair of craniosynostosis: 16 had craniosynostosis repair as well as CM decompression, and 13 patients did not undergo CM decompression. Of the 7 patients in whom craniosynostosis repair alone was performed, 5 had decreased tonsillar ectopia postoperatively and 5 had improved CSF flow studies postoperatively. Both patients with a spinal syrinx had imaging-documented syrinx regression after craniosynostosis repair. In 12 patients in whom CM was diagnosed after primary craniosynostosis repair, 5 had multiple cranial vault expansions and evidence of elevated intracranial pressure. In 5 cases, de novo CM development was documented following craniosynostosis repair at a mean of 3.5 years after surgery.

CONCLUSIONS

Chiari malformation is frequently seen in patients with both multi- and single-suture lambdoid craniosynostosis. Chiari malformation, and even a spinal cord syrinx, will occasionally resolve following craniofacial repair. De novo development of CM after craniosynostosis repair is not unusual.

Associated disorders of Chiari Type I malformations: a review

A single pathophysiological mechanism of Chiari Type I malformations (CM-I) has been a topic of debate. To help better understand CM-I, the authors review disorders known to be associated with CM-I. The primary methodology found among most of them is deformation of the posterior cranial fossa, usually with subsequent decrease in volume. Other mechanisms exist as well, which can be categorized as either congenital or acquired. In understanding the relationship of such disorders with CM-I, we may gain further insight into the process by which cerebellar tonsillar herniation occurs. Some of these pathologies appear to be true associations, but many appear to be spurious.

Pansynostosis: a review

INTRODUCTION

Although rare, pansynostoses are seen and treated by the craniofacial surgeon. To date, a single source that reviews these more severe forms of craniosynostosis is lacking in the literature.

MATERIALS AND METHODS

The present paper outlines and reviews the associations of both syndromic and nonsyndromic cases, potential mechanisms, and the anatomy involved with such forms of premature fusion of the cranial sutures.

RESULTS

Pansynostosis is seen in a myriad of syndromes but can also be identified in nonsyndromic cases. Raised intracranial pressure is a concern in these patients.

CONCLUSIONS

Early recognition and treatment of patients with pansynostosis of the cranial sutures is important.

Chiari malformation in craniosynostosis

INTRODUCTION

Chiari malformation (CM) is a frequent finding in multisutural and syndromic craniosynostosis, occurring in 70% of patients with Crouzon's syndrome, 75% with oxycephaly, 50% with Pfeiffer's syndrome and 100% with the Kleeblattschädel deformity. The pathogenesis of this condition and rationale for treatment are still controversial.

DISCUSSION

Since its first description in 1972, several factors have been cited to play a role in inducing CM. In the light of recent publications, the roles of premature fusion of cranial vault and cranial base sutures, of congenital anomalies of the cerebellum and brain stem, of raised intracranial pressure, of venous hypertension and of hydrocephalus are reviewed. Evaluation and management of CM are also discussed.

CONCLUSION

Chiari malformation appears to be an acquired and progressive condition that develops in the first months of life, because of a disproportion between hindbrain growth and an abnormally small posterior fossa, a consequence of the premature fusion of lambdoid and cranial base sutures. Venous hypertension caused by stenosis of the jugular foramen can also be present in these patients, resulting in intracranial hypertension and/or hydrocephalus. Careful MRI evaluation is recommended for the forms of craniosynostosis at a high risk of developing hindbrain herniation. The selection of posterior cranial vault expansion as the first surgical procedure is advocated. In selected cases, treatment of the posterior cranial deformity by occipital vault remodelling and treatment of the Chiari-like deformity by suboccipital decompression can be carried out using the same surgical procedure.

The role of cranial expansion for craniocephalic disproportion

The appropriate treatment for craniocephalic disproportion, such as caused by slit ventricle syndrome, is uncertain. We have reviewed the treatment and outcomes of 4 children who underwent cranial expansion over a period of 5 years. The ages at cranial expansion were 16 months, 3 years 6 months and 2 at 6 years. Two children had slit ventricle syndrome and were treated with bilateral parietal expansions. Two children had non-syndromic craniosynostosis, one of these having vitamin D-resistant rickets. The latter 2 were treated with posterior cranial vault expansion, and one also had a craniocervical junction decompression performed. Post-operatively, symptoms of raised intracranial pressure resolved in all cases, and there was radiological evidence of re-establishment of normal CSF pathways. Although a rare condition, cranial expansion operations can be successful in appropriately selected cases of craniocephalic disproportion.

Association of the Adult Chiari Malformation and Idiopathic Intracranial Hypertension: more than a coincidence

There are significant similarities between the Adult Chiari Malformation (ACM) and Idiopathic Intracranial Hypertension (IIH). They include similar demographics, clinical presentation, and response to treatment. There is an eightfold increase in the incidence of significant tonsillar herniation in patients with IIH. Based on these findings and our observation in a subgroup of patients with failed ACM decompression, we suggest that these disorders are interrelated in a group of patients. The physiopathology is that of craniocephalic disproportion, i.e., a disproportion between the skull and the brain, due to a small skull or posterior fossa (like in ACM) and/or an engorged brain (like in IIH). This will occasionally lead to tonsillar ectopia. The craniocephalic disproportion will alter the brain compliance and lead to the symptomatology.

Definition of the adult Chiari malformation: a brief historical overview

With the widespread use of newer neuroimaging techniques and modalities, significant tonsillar herniation is being diagnosed in more than 0.5% of patients, some of whom are asymptomatic. This puts the definition of the adult Chiari malformation to the test. The author provides a historical review of the evolution of the definition of the adult Chiari malformation in the neurosurgery, radiology, and pathology literature.