Aneurysmal subarachnoid hemorrhage in young adults

Chiari I Deformity: Beyond 5 mm below the Foramen Magnum

Although originally described as a consecutive series of pathologic changes, Chiari syndrome represents a spectrum of disease divided into two subsets: development deformities of the paraxial mesoderm manifesting after birth (types 0-1.5) and true congenital malformations due to failure of neural tube closure present in utero (types 2-5). Heterogeneity among patients with a Chiari deformity and incomplete understanding of its pathophysiologic characteristics have led to inconsistency in radiologic reporting and difficulty in defining appropriate management strategies tailored to an individual patient's condition. The radiologist is tasked with going beyond the criteria for cerebellar tonsillar herniation to define an individual patient's disease state, determine candidacy for surgery, and assist in selecting the proper surgical approach. In addition, the radiologist must be able to identify conditions that result in cerebellar tonsillar herniation that are not related to Chiari deformity to avoid inappropriate surgery. Last, the radiologist must be able to interpret postoperative imaging examinations to assess for adequacy of treatment and complications. The authors summarize recent literature regarding the pathophysiologic basis of Chiari 1 and related deformities and detail the ideal morphologic and physiologic imaging assessment, focusing on Chiari 1 and related deformities (Chiari 0, 0.5, and 1.5). Also discussed are surgical techniques and "pearls" of postsurgical imaging, including complications that must be recognized. This review provides clarity to a commonly encountered but less understood condition to optimize outcomes for patients with Chiari 1 and related deformities. ©RSNA, 2024 Supplemental material is available for this article. See the invited commentary by Huisman in this issue.

The craniovertebral junction, between osseous variants and abnormalities: insight from a paleo-osteological study

The bony components of the craniovertebral junction (CVJ) have been investigated in 172 skeletons, dug up from several archaeological sites, to define the frequency of developmental dysmorphisms, and to acquire qualitative and quantitative data about their morphology. A review of the pertinent literature is also presented. Twenty-five individuals (14.5%) exhibited at least one dysmorphism, which ranged from a condition of simple variant to a true malformation. Four individuals presented two or more anomalies at the same time (2.3% of the whole sample, 16% of the affected individuals). The most frequently observed abnormalities were: (i) the presence of a complete bony bridge in the atlas, forming a canal surrounding the vertebral artery (arcuate foramen, supertransverse foramen, and the simultaneous occurrence of arcuate foramen and supertransverse foramen); (ii) the presence of basilar processes. Basilar processes displayed a great variety in shape and dimension. They also differed with respect to their relationship with atlas and axis. The less frequently detected anomalies were: (i) complete absence of the posterior arch of C1, (ii) fusion of C2 and C3, and (iii) irregular segmentation of C2. A broad array of structural defects has been described at the CVJ. They may occur either isolated or as part of complex multisystem syndromes. Although harmless in many cases, they can notwithstanding cause severe, even life-threatening complications. When unrecognized, they may generate trouble during surgery. Hence, accurate knowledge of CVJ arrangement, including its multifarious variations, is a critical issue for radiologists, clinicians, surgeons, and chiropractors.

Preoperative measurements on MRI in Chiari 1 patients fail to predict outcome after decompressive surgery

Background

The purpose of our study was to research the parameters of magnetic resonance imaging (MRI) that would predict the outcome of surgery in patients with Chiari 1 malformation (CM1) and to evaluate changes in MRI parameters after surgery.

Methods

Fifty-one patients (19 children, 13 adolescents, and 19 adults) operated on due to CM1 in Oulu University Hospital between 2004 and 2018 were evaluated. Seventeen parameters were measured from the preoperative MRI and 11 from the postoperative MRI. The correlations between the MRI parameters and the clinical variables before and after surgery were analyzed.

Results

The majority (88.2%) of the patients had favorable surgical outcomes. Postoperatively, subjective symptoms improved in 88.6% of the patients and syringomyelia in 81.8%. The location of the cerebellar tonsils, when measured in relation to the C2 synchondrosis or the end plate, postoperatively moved cranially in 51.0% (n = 26), did not change in 27.4% (n = 14), and moved caudally in 21.6% (n = 11) of the patients. However, neither the location of the tonsils nor any other parameters measured from pre- or postoperative MRI correlated with the patients’ symptoms or surgical outcomes.

Conclusions

No specific parameters on preoperative MRI evaluation were predictive of the outcome of surgery, emphasizing clinical examination in surgical decision-making. Furthermore, the postoperative MRI parameters did not correlate with the surgical outcomes. Thus, routine postoperative imaging is suggested only for patients with preoperatively diagnosed syringomyelia or worsening of symptoms.

Chiari I-a 'not so' congenital malformation?

The term Chiari I malformation (CIM) is imbedded in the paediatric neurosurgical lexicon; however, the diagnostic criteria for this entity are imprecise, its pathophysiology variable, and the treatment options diverse. Until recently, CIM has been considered to be a discrete congenital malformation requiring a uniform approach to treatment. Increasingly, it is recognised that this is an oversimplification and that a more critical, etiologically based approach to the evaluation of children with this diagnosis is essential, not only to select those children who might be suitable for surgical treatment (and, of course those who might be better served by conservative management) but also to determine the most appropriate surgical strategy. Whilst good outcomes can be anticipated in the majority of children with CIM following foramen magnum decompression, treatment failures and complication rates are not insignificant. Arguably, poor or suboptimal outcomes following treatment for CIM reflect, not only a failure of surgical technique, but incorrect patient selection and failure to acknowledge the diverse pathophysiology underlying the phenomenon of CIM. The investigation of the child with 'hindbrain herniation' should be aimed at better understanding the mechanisms underlying the herniation so that these may be addressed by an appropriate choice of treatment.

Defining, diagnosing, clarifying, and classifying the Chiari I malformations

PURPOSE

Chiari malformations (CM) have been traditionally classified into four categories: I, II, III, and IV. In light of more recent understandings, variations of the CM have required a modification of this classification.

METHODS

This article discusses the presentation, diagnostics, and treatment of the newer forms of hindbrain herniation associated with the CM type I.

RESULTS

The CM 1 is a spectrum that includes some patients who do not fall into the exact category of this entity.

CONCLUSIONS

While CM have been categorically recognized as discrete and individual conditions, newer classifications such as CM 0 and CM 1.5 exhibit some degree of continuity with CM 1; however, they require distinct and separate classification as symptoms and treatments can vary among these clinical subtypes.

Chiari type I malformation of infants and toddlers

OBJECTIVES

Chiari I malformation has been a well-recognized clinical entity; however, its occurrence among infants and toddlers is unusual. Their clinical presentations may be different from other age groups due to their lack of effective verbal communication. The authors analyze their personal series of patients focusing on symptomatology and MRI characteristics. Treatment methods, results, and outcome are analyzed in order to identify appropriate surgical management among infants and toddlers with Chiari I malformation.

METHODS

The authors retrospectively reviewed 16 patients who were diagnosed and surgically treated between 2007 and 2014 during the first 3 years of life with minimum follow-up of 3 years. We focused on the presenting symptoms, magnetic resonance imaging findings, and surgical techniques used for posterior fossa decompression (PFD) and their postoperative outcome.

RESULTS

Twelve patients (75%) presented with signs of headaches such as irritability, inconsolable crying, head grabbing, and/or arching back. Ten patients (62.5%) presented with oropharyngeal and/or respiratory symptoms such as emesis, choking, gagging, snoring, sleep apnea, breathing pause, and/or vocal cord palsy. Only one patient had segmental cervical hydromyelia. At the first surgery, ten patients had PFD with dural scoring (Type 1 procedure), while six others had PFD with duraplasty (Type 2 procedure) with thermal reduction of the cerebellar tonsils in four. Following the first operation, all initially had varying degrees of symptomatic improvement; however, seven patients subsequently had symptomatic recurrence. Persistent crowding at the PFD site on the postoperative imaging indicated greater risk of recurrences in both Type 1 procedure and Type 2 procedure groups. Of seven patients who needed a second operation, fivewere after Type 1 procedure and the two were after Type 2 procedure. The difference of recurrence rates between these two groups is not significant. CSF-related complications occurred in 4 out of 11 patients who had Type 2 procedure (one after primary decompression and three after the second decompression for recurrence).

CONCLUSION

Young patients lacking effective verbal communication often present their Chiari I malformation differently from olderage groups. Behavioral changes indicative of headaches/irritability and oropharyngeal/respiratory symptoms are the primary presenting symptoms. The recurrence rate tends to be higher among the patients after Type 1 procedure (particularly those younger than 18 months) than after Type 2 procedure. We observed that duraplasty at primary or at redo PFD provides for better decompression and long-term outcome. However, one should keep it in mind that there is risk of CSF-related complications following duraplasty, particularly higher tendency after redo PFD.

Odontoid process inclination in normal adults and in an adult population with Chiari malformation Type I

OBJECT

Posterior odontoid process inclination has been demonstrated as a factor associated with Chiari malformation Type I (CM-I) in the pediatric population; however, no studies to date have examined this measurement in the adult CM-I population. The purpose of this study was to evaluate craniocervical junction (CCJ) measurements in adult CM-I versus a control group.

METHODS

The odontoid retroflexion, odontoid retroversion, odontoid height, posterior basion to C-2 line measured to the dural margin (pB-C2 line), posterior basion to C-2 line measured to the dorsal odontoid cortical margin (pB-C2* line), and clivus-canal angle measurements were retrospectively analyzed in adult patients with CM-I using MRI. These measurements were compared with normative values established from CT scans of the cervical spine in adults without CM-I.

RESULTS

A statistically significant difference was found between 55 adults with CM-I and 150 sex-matched controls (125 used for analysis) in the mean clivus-canal angle and the mean pB-C2 line.

CONCLUSIONS

These data suggest that there are sex-specific differences with respect to measurements at the CCJ between men and women, with women showing a more posteriorly inclined odontoid process. There were also differences between the CM-I and control groups: a more acute clivus-canal angle was associated with CM-I in the adult population. These CCJ findings could have an influence on presurgical planning.

The Role of the Craniocervical Junction in Craniospinal Hydrodynamics and Neurodegenerative Conditions

The craniocervical junction (CCJ) is a potential choke point for craniospinal hydrodynamics and may play a causative or contributory role in the pathogenesis and progression of neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, MS, and ALS, as well as many other neurological conditions including hydrocephalus, idiopathic intracranial hypertension, migraines, seizures, silent-strokes, affective disorders, schizophrenia, and psychosis. The purpose of this paper is to provide an overview of the critical role of the CCJ in craniospinal hydrodynamics and to stimulate further research that may lead to new approaches for the prevention and treatment of the above neurodegenerative and neurological conditions.

Posterior odontoid process angulation in pediatric Chiari I malformation: an MRI morphometric external validation study

OBJECT Osseous anomalies of the craniocervical junction are hypothesized to precipitate the hindbrain herniation observed in Chiari I malformation (CM-I). Previous work by Tubbs et al. showed that posterior angulation of the odontoid process is more prevalent in children with CM-I than in healthy controls. The present study is an external validation of that report. The goals of our study were 3-fold: 1) to externally validate the results of Tubbs et al. in a different patient population; 2) to compare how morphometric parameters vary with age, sex, and symptomatology; and 3) to develop a correlative model for tonsillar ectopia in CM-I based on these measurements. METHODS The authors performed a retrospective review of 119 patients who underwent posterior fossa decompression with duraplasty at the Monroe Carell Jr. Children's Hospital at Vanderbilt University; 78 of these patients had imaging available for review. Demographic and clinical variables were collected. A neuroradiologist retrospectively evaluated preoperative MRI examinations in these 78 patients and recorded the following measurements: McRae line length; obex displacement length; odontoid process parameters (height, angle of retroflexion, and angle of retroversion); perpendicular distance to the basion-C2 line (pB-C2 line); length of cerebellar tonsillar ectopia; caudal extent of the cerebellar tonsils; and presence, location, and size of syringomyelia. Odontoid retroflexion grade was classified as Grade 0, > 90°; Grade I,85°-89°; Grade II, 80°-84°; and Grade III, < 80°. Age groups were defined as 0-6 years, 7-12 years, and 13-17 years at the time of surgery. Univariate and multivariate linear regression analyses, Kruskal-Wallis 1-way ANOVA, and Fisher's exact test were performed to assess the relationship between age, sex, and symptomatology with these craniometric variables. RESULTS The prevalence of posterior odontoid angulation was 81%, which is almost identical to that in the previous report (84%). With increasing age, the odontoid height (p < 0.001) and pB-C2 length (p < 0.001) increased, while the odontoid process became more posteriorly inclined (p = 0.010). The pB-C2 line was significantly longer in girls (p = 0.006). These measurements did not significantly correlate with symptomatology. Length of tonsillar ectopia in pediatric CM-I correlated with an enlarged foramen magnum (p = 0.023), increasing obex displacement (p = 0.020), and increasing odontoid retroflexion (p < 0.001). CONCLUSIONS Anomalous bony development of the craniocervical junction is a consistent feature of CM-I in children. The authors found that the population at their center was characterized by posterior angulation of the odontoid process in 81% of cases, similar to findings by Tubbs et al. (84%). The odontoid process appeared to lengthen and become more posteriorly inclined with age. Increased tonsillar ectopia was associated with more posterior odontoid angulation, a widened foramen magnum, and an inferiorly displaced obex.

Morphology of the foramen magnum in syndromic and non-syndromic brachycephaly

PURPOSE

The shape and size of the foramen magnum (FM) can be altered in craniosynostoses. However, few studies have investigated these changes. In this paper, we investigate the morphology of the foramen magnum in syndromic and non-syndromic brachycephaly.

METHODS

Surface area, anteroposterior (AP) diameter, and transverse diameters of the FM were measured on high-resolution CT scans in children with Crouzon (25), Pfeiffer (21), Apert (26), Saethre-Chotzen (7) syndromes, and isolated bicoronal synostosis (9) and compared to an age-matched control group (30).

RESULTS

A significantly smaller FM surface area was observed in Crouzon (6.3 ± 1.7 cm(2)) and Pfeiffer (6.4 ± 2.3 cm(2)) syndromes as compared to the control group (7.4 ± 1.3 cm(2), p = 0.006 and p = .017, respectively). In comparison to the control group, no statistically significant alteration in FM surface area was noted in patients with Apert, Saethre-Chotzen, or isolated bicoronal synostosis (p = 0.37, p = 0.71, p = 0.40 respectively). The transverse diameter of FM was significantly smaller in Crouzon, Pfeiffer, and Apert syndromes compared to the control group (p = 0.005, p = 0.002, p = 0.03 respectively). In Saethre-Chotzen and isolated bicoronal synostosis, no difference in transverse diameter was demonstrated. Among all groups, only Crouzon syndrome showed reduced anteroposterior diameter as compared to controls (p = 0.005). In Pfeiffer and Apert syndromes, there was elongation of the shape of the FM with a relatively narrowed width as demonstrated in a significantly increased AP to transverse diameter ratio (p = 0.002 and p = 0.019, respectively).

DISCUSSION AND CONCLUSIONS

The FM shape and area is significantly altered in fibroblast growth factor receptor (FGFR)-related brachycephaly syndromes (Crouzon, Pfeiffer, and Apert), whereas in patients with Saethre-Chotzen syndrome (TWIST-1 mutation) and isolated non-syndromic bicoronal synostosis, the shape and mean FM area was not statistically different from that of normals. This study brings to light the important role of FGFRs on FM growth and shape. TWIST-1 mutation (Saethre-Chotzen syndrome) does not appear to have an important effect in shaping the FM.

Evaluating the relationship of the pB-C2 line to clinical outcomes in a 15-year single-center cohort of pediatric Chiari I malformation

OBJECT

The clinical significance of radiological measurements of the craniocervical junction in pediatric Chiari I malformation (CM-I) is yet to be fully established across the field. The authors examined their institutional experience with the pB-C2 line (drawn perpendicular to a line drawn between the basion and the posterior aspect of the C-2 vertebral body, at the most posterior extent of the odontoid process at the dural interface). The pB-C2 line is a measure of ventral canal encroachment, and its relationship with symptomatology and syringomyelia in pediatric CM-I was assessed.

METHODS

The authors performed a retrospective review of 119 patients at the Monroe Carell Jr. Children's Hospital at Vanderbilt University who underwent posterior fossa decompression with duraplasty, 78 of whom had imaging for review. A neuroradiologist retrospectively evaluated preoperative and postoperative MRI examinations performed in these 78 patients, measuring the pB-C2 line length and documenting syringomyelia. The pB-C2 line length was divided into Grade 0 (<3 mm) and Grade I (≥3 mm). Statistical analysis was performed using the t-test for continuous variables and Fisher's exact test analysis for categorical variables. Multivariate logistic and linear regression analyses were performed to assess the relationship between pB-C2 line grade and clinical variables found significant on univariate analysis, controlling for age and sex.

RESULTS

The mean patient age was 8.5 years, and the mean follow-up duration was 2.4 years. The mean pB-C2 line length was 3.5 mm (SD 2 mm), ranging from 0 to 10 mm. Overall, 65.4% of patients had a Grade I pB-C2 line. Patients with Grade I pB-C2 lines were 51% more likely to have a syrinx than those with Grade 0 pB-C2 lines (RR 1.513 [95% CI 1.024-2.90], p=0.021) and, when present, had greater syrinx reduction (3.6 mm vs 0.2 mm, p=0.002). Although there was no preoperative difference in headache incidence, postoperatively patients with Grade I pB-C2 lines were 69% more likely to have headache reduction than those with Grade 0 pB-C2 lines (RR 1.686 [95% CI 1.035-2.747], p=0.009). After controlling for age and sex, pB-C2 line grade remained an independent correlate of headache improvement and syrinx reduction.

CONCLUSIONS

Ventral canal encroachment may explain the symptomatology of select patients with CM-I. The clinical findings presented suggest that patients with Grade I pB-C lines2, with increased ventral canal obstruction, may experience a higher likelihood of syrinx reduction and headache resolution from decompressive surgery with duraplasty than those with Grade 0 pB-C2 lines.

Magnetic resonance imaging features of complex Chiari malformation variant of Chiari 1 malformation

BACKGROUND

Complex Chiari malformation is a subgroup of Chiari 1 malformation with distinct imaging features. Children with complex Chiari malformation are reported to have a more severe clinical phenotype and sometimes require more extensive surgical treatment than those with uncomplicated Chiari 1 malformation.

OBJECTIVE

We describe reported MR imaging features of complex Chiari malformation and evaluate the utility of craniometric parameters and qualitative anatomical observations for distinguishing complex Chiari malformation from uncomplicated Chiari 1 malformation.

MATERIALS AND METHODS

We conducted a retrospective search of the institutional imaging database using the keywords "Chiari" and "Chiari 1" to identify children imaged during the 2006-2011 time period. Children with Chiari 2 malformation were excluded after imaging review. We used the first available diagnostic brain or cervical spine MR study for data measurement. Standard measurements and observations were made of obex level (mm), cerebellar tonsillar descent (mm), perpendicular distance to basion-C2 line (pB-C2, mm), craniocervical angle (degrees), clivus length, and presence or absence of syringohydromyelia, basilar invagination and congenital craniovertebral junction osseous anomalies. After imaging review, we accessed the institutional health care clinical database to determine whether each subject clinically met criteria for Chiari 1 malformation or complex Chiari malformation.

RESULTS

Obex level and craniocervical angle measurements showed statistically significant differences between the populations with complex Chiari malformation and uncomplicated Chiari 1 malformation. Cerebellar tonsillar descent and perpendicular distance to basion-C2 line measurements trended toward but did not meet statistical significance. Odontoid retroflexion, craniovertebral junction osseous anomalies, and syringohydromyelia were all observed proportionally more often in children with complex Chiari malformation than in those with Chiari 1 malformation.

CONCLUSION

Characteristic imaging features of complex Chiari malformation, especially obex level, permit its distinction from the more common uncomplicated Chiari 1 malformation.

Therapeutic implications of estrogen for cerebral vasospasm and delayed cerebral ischemia induced by aneurysmal subarachnoid hemorrhage

Cerebral vasospasm (CV) remains the leading cause of delayed morbidity and mortality following aneurysmal subarachnoid hemorrhage (SAH). However, increasing evidence supports etiologies of delayed cerebral ischemia (DCI) other than CV. Estrogen, specifically 17 β -estradiol (E2), has potential therapeutic implications for ameliorating the delayed neurological deterioration which follows aneurysmal SAH. We review the causes of CV and DCI and examine the evidence for E2-mediated vasodilation and neuroprotection. E2 potentiates vasodilation by activating endothelial nitric oxide synthase (eNOS), preventing increased inducible NOS (iNOS) activity caused by SAH, and decreasing endothelin-1 production. E2 provides neuroprotection by increasing thioredoxin expression, decreasing c-Jun N-terminal kinase activity, increasing neuroglobin levels, preventing SAH-induced suppression of the Akt signaling pathway, and upregulating the expression of adenosine A2a receptor. The net effect of E2 modulation of these various effectors is the promotion of neuronal survival, inhibition of apoptosis, and decreased oxidative damage and inflammation. E2 is a potentially potent therapeutic tool for improving outcomes related to post-SAH CV and DCI. However, clinical evidence supporting its benefits remains lacking. Given the promising preclinical data available, further studies utilizing E2 for the treatment of patients with ruptured intracranial aneurysms appear warranted.

Estimation of odontoid process posterior inclination, odontoid height, and pB–C2 line in the adult population

Object

Posterior odontoid process inclination has been associated with Chiari malformation Type I in the pediatric population. There are varying reports to support a reliable range of odontoid inclination angles in control adults. The purpose of this study is to estimate the normal measurements in adults for odontoid retroflexion, retroversion, height, and the pB–C2 line (a line drawn through the odontoid tip from the ventral dura perpendicular to a second line from drawn the basion to the inferoposterior aspect of C-2 vertebral body) to establish a normative reference in this population.

Methods

After obtaining institutional review board approval, the authors performed a retrospective analysis of non–contrast enhanced cervical spine CT scans obtained in 150 consecutive control adults. Three neuroradiologists measured odontoid retroflexion, odontoid retroversion, odontoid height, and the pB–C2 line. The cohort was divided into sex and two age groups. Comparisons of the means with unpaired 2-tailed t-test were performed.

Results

A total of 125 subjects met the inclusion criteria; 80 were men and 45 were women (mean age 52 years, range 18–89 years). The odontoid retroflexion angle ranged from 70° to 89° (mean 79.3° ± 4.9°), and the odontoid retroversion angle ranged from 57° to 87° (mean 71.9° ± 5.3°). The range and mean of odontoid height were 17–27 mm and 22 ± 1.8 mm, respectively. The mean pB–C2 line was 6.5 ± 2.1 mm with a range of 0–11.2 mm. The results were also compared with previously published pediatric data.

Conclusions

The current study demonstrates that the odontoid process in adults is anatomically different from that in children: it is longer, more posteriorly inclined, and has a greater pB–C2 line. Therefore, utilization of these parameters with previously published cutoffs in the pediatric population is not appropriate for surgical planning in adults.

Worsening or development of syringomyelia following Chiari I decompression: case report

OBJECT

The effects of posterior fossa decompression on Chiari malformation Type I-induced syringomyelia have been well described. However, treatment of worsening syringomyelia after Chiari decompression remains enigmatic. This paper defines patient and clinical characteristics as well as treatment and postoperative radiological and clinical outcomes in patients experiencing this complication.

METHODS

The authors performed a retrospective review of patients at the Children's Hospital of Pittsburgh and Children's of Alabama who developed worsening syringomyelia after Chiari decompression was performed.

RESULTS

Fourteen children (age range 8 months to 15 years), 7 of whom had preoperative syringomyelia, underwent posterior fossa decompression. Aseptic meningitis (n = 3) and bacterial meningitis (n = 2) complicated 5 cases (4 of these patients were originally treated at outside hospitals). Worsening syringomyelia presented a median of 1.4 years (range 0.2-10.3 years) after the primary decompression. Ten children presented with new, recurrent, or persistent symptoms, and 4 were asymptomatic. Secondary Chiari decompression was performed in 11 of the 14 children. The other 3 children were advised to undergo secondary decompression. A structural cause for each failed primary Chiari decompression (for example, extensive scarring, suture in the obex, arachnoid web, residual posterior arch of C-1, and no duraplasty) was identified at the secondary operation. After secondary decompression, 8 patients' symptoms completely resolved, 1 patient's condition stabilized, and 2 patients remained asymptomatic. Radiologically, 10 of the 11 children had a decrease in the size of their syringes, and 1 child experienced no change (but improved clinically). The median follow-up from initial Chiari decompression was 3.1 years (range 0.8-14.1 years) and from secondary decompression, 1.3 years (range 0.3-4.5 years). No patient underwent syringopleural shunting or other nonposterior fossa treatment for syringomyelia.

CONCLUSIONS

Based on the authors' experience, children with worsening syringomyelia after decompression for Chiari malformation Type I generally have a surgically remediable structural etiology, and secondary exploration and decompression should be considered.

Aneurysmal subarachnoid hemorrhage in third and fourth decades of life

Objective

The aim of this study was to compare clinical characteristics of ruptured aneurysms in young adults, of the third and fourth decades of life, and to compare several clinical characteristics affecting the outcome of patients.

Methods

We retrospectively investigated 1459 patients who underwent surgery and endovascular treatment for ruptured cerebral aneurysms from June 1992 to December 2010 and compared clinical characteristics. We also reviewed pre-existing medical conditions and perioperative complications.

Results

Among 1459 patients, there were 21 patients (1.44%) in the third decade and 104 patients (7.13%) in the fourth decade of life. Within two age groups, 88 (70.4%) were male and 37 (29.6%) were female, a ratio of 2.37 : 1. In both groups, we observed the anterior cerebral artery (ACA) aneurysm with the most frequency (p=0.028). In general, favorable outcome was achieved in both age groups (90.5% and 81.7%, respectively). An initial univariate analysis showed Hunt-Hess grade, Fisher grade, location of aneurysm, and rebleeding significantly associated with outcome after aneurysm rupture. Further, multivariate analysis demonstrated that only Hunt-Hess grade (grade 4-5) was a risk factor for the outcome (odds ratio=9.730, 95% confidence interval 2.069-45.756, p=0.004).

Conclusion

The incidence of subarachnoid hemorrhage (SAH) was higher in the male population of the third and fourth decades of life. Aneurysms on the ACA were most frequently occurred in both age groups and the outcome of aneurysmal SAH among the third and fourth decades was favorable. Multivariate analysis revealed that high Hunt-Hess grade was a risk factor for patient's outcome.

Aneurysmal subarachnoid hemorrhage in patients under 35-years-old: a single-center experience

OBJECTIVE

Aneurysmal subarachnoid hemorrhage (SAH) is relatively uncommon in young adults. There is a paucity of data pertaining to the management of aneurysmal SAH in young patients, especially with endovascular therapy.

METHODS

We reviewed all SAH patients under the age of 35 years treated at Jefferson Hospital for Neuroscience, Philadelphia, USA, from 2004 to 2009.

RESULTS

A total of 40 patients (15 males and 25 females) under the age of 35 were treated for aneurysmal SAH. The average patient age was 30 years (17-35 yo); 25 (62.5%) were smokers. Seventeen patients presented with a Hunt and Hess Grade I or II (42.5%), 20 with a Grade III (50%), and 3 with a Grade IV (7.5%). Thirty-two aneurysms (80%) were located in the anterior circulation and 8 (20%) in the posterior circulation. Thirty-five patients (87.5%) were treated with coil embolization versus 5 with craniotomy and clipping. The endovascular and microsurgical occlusion rates were 90.6% and 100%, respectively. There were no procedural complications with endovascular therapy. Of 35 patients undergoing endovascular treatment, 24 (68.6%) had excellent outcomes at time of discharge with a Glasgow outcome scale of 5. There were no deaths in the series. No patient experienced a rehemorrhage after endovascular treatment.

CONCLUSION

Smoking, female sex, and anterior circulation aneurysms are highly prevalent in young adults with SAH. Endovascular treatment resulted in an overall favorable outcome with no rehemorrhages in patients under the age of 35 years. Our results suggest that endovascular therapy is a reasonable treatment for young patients with SAH.

Chiari malformation Type I and syrinx in children undergoing magnetic resonance imaging

OBJECT

Chiari malformation Type I (CM-I) with an associated spinal syrinx is a common pediatric diagnosis. A better understanding of the relative age-related prevalence and MR imaging characteristics of these associated conditions may lead to improved treatment decisions.

METHODS

The authors performed a retrospective review of 14,116 consecutive individuals 18 years of age or younger who had undergone brain or cervical spine MR imaging at the University of Michigan between November 1997 and August 2008. In the patients with CM-I, demographic, clinical, and radiographic information was recorded.

RESULTS

Five hundred nine children (3.6%) with CM-I were identified. Among these patients, 23% also had a spinal cord syrinx, and 86% of the syringes were found in the cervical spine. The MR imaging prevalence of CM-I with a syrinx was 1.2% in girls and 0.5% in boys (p < 0.0001). The severity of impaired CSF flow at the foramen magnum was associated with the amount of tonsillar herniation (p < 0.0001) and conformation of the tonsils (p < 0.0001). Patients with CM-I were treated surgically in 35% of cases; these patients exhibited more severe tonsillar herniation (p < 0.0001) and impaired CSF flow (p < 0.0001) as compared with those who did not undergo surgery. On imaging, 32% of all the patients with CM-I were considered symptomatic by the treating physician. Patients were more likely to be considered symptomatic if they were female, had a syrinx, displayed abnormal tonsillar pulsations, or had a greater amount of tonsillar herniation.

CONCLUSIONS

In this study the authors describe the age-related prevalence and MR imaging characteristics of CM-I and its association with a syrinx and other abnormalities in a large group of children who underwent MR imaging for any indication. Syringes are more common in older children, in girls, and in patients with a greater degree of tonsillar descent and CSF flow impairment.

Institutional experience with 500 cases of surgically treated pediatric Chiari malformation Type I

OBJECT

The diagnosis and treatment of Chiari malformation Type I (CM-I) has evolved over the last few decades. The authors present their surgical experience of over 2 decades of treating children with this form of hindbrain herniation.

METHODS

The authors conducted a retrospective review of their institutional experience with the surgical treatment of the pediatric CM-I from 1989 to 2010.

RESULTS

The 2 most common presentations were headache/neck pain (40%) and scoliosis (18%). Common associated diagnoses included neurofibromatosis Type 1 (5%) and idiopathic growth hormone deficiency (4.2%). Spine anomalies included scoliosis (18%), retroversion of the odontoid process (24%), Klippel-Feil anomaly (3%), and atlantooccipital fusion (8%). Approximately 3% of patients had a known family member with CM-I. Hydrocephalus was present in 48 patients (9.6%). Syringomyelia was present in 285 patients (57%), and at operation, 12% of patients with syringomyelia were found to have an arachnoid veil occluding the fourth ventricular outlet. Fifteen patients (3%) have undergone reoperation for continued symptoms or persistent large syringomyelia. The most likely symptoms and signs to resolve following surgery were Valsalva-induced headache and syringomyelia. The average hospital stay and "return to school" time were 3 and 12 days, respectively. The follow-up for this group ranged from 2 months to 15 years (mean 5 years). Complications occurred in 2.4% of cases; there was no mortality. No patient required acute return to the operating room, and no blood transfusions were performed.

CONCLUSIONS

The authors believe this to be the largest reported series of surgically treated pediatric CM-I patients and hope that their experience will be of use to others who treat this surgical entity.

Chiari 1.5 malformation : an advanced form of Chiari I malformation

The Chiari 1.5 malformation is defined as a tonsillar herniation within a Chiari I malformation with additional caudal descent of the brainstem through the foramen magnum. We describe a patient with Chiari I malformation who evolved to Chiari 1.5 malformation during longitudinal follow-up. A 15-year-old girl presented with neck pain during exercise for two years. She had been diagnosed with Chiari I malformation with mild hydrocephalus after minor cervical trauma at the age of six years. At that time, she was asymptomatic. After she complained of aggravated neck pain, neuroimaging (nine years after first imaging) revealed caudal descent of the brainstem and syringomyelia in addition to progression of tonsillar herniation. Posterior fossa decompressive surgery resulted in complete resolution of neck pain. Based on neuroimaging and operative findings, she was diagnosed as Chiari 1.5 malformation. Neuroimaging performed seven months after surgery showed an increased anterior-posterior diameter of the medulla oblongata and markedly decreased syringomyelia. This case demonstrates progressive developmental process of the Chiari 1.5 malformation as an advanced form of the Chiari I malformation.

Incidental neuroimaging findings in nonacute headache

We studied the frequency and consequences of incidental neuroimaging findings in 400 otherwise healthy, nonacute pediatric headache patients through a retrospective, cross-sectional analysis. We excluded patients with currently recommended clinical criteria to consider diagnostic neuroimaging. We categorized neuroimaging results as normal, remarkable without clinical action, remarkable with clinical follow-up action, and abnormal. One hundred eighty-five of 400 patients (46%) had neuroimaging. Of these, 78.4% of neuroimaging studies were normal, and none was considered abnormal. Also, 21.5% had remarkable findings in the neuroradiology report. The frequency and types of all incidental findings were generally comparable to previous studies. One third of these patients received further consultation or neuroimaging because of incidental findings. In the evaluation of nonacute pediatric headache, overuse of neuroimaging leads to frequent discovery of incidental findings and increased testing. Individualized health care calls for physician-consumer discussions about current indications for neuroimaging, the general frequency of incidental findings, and potential difficulties in their interpretation.

C1-C2 arthrodesis after transoral odontoidectomy and suboccipital craniectomy for ventral brain stem compression in Chiari I patients

Chiari I malformations are often associated with congenital craniocervical anomalies such as platybasia, basilar invagination, and retroflexion of the odontoid process. Management of ventral brain stem compression associated with Chiari I malformations remains controversial, but several authors report a significant rate of failure with suboccipital decompression alone in the presence of pronounced ventral brain stem compression (VBSC). Treatment options described in the literature for these patients involve anterior, posterior, or combined decompressions with or without concurrent arthrodesis. A combined anterior and posterior approach provides a definitive circumferential decompression but also significantly disrupts the stability of the occipitocervical junction usually necessitating occipitocervical fixation. We describe an alternative surgical treatment for Chiari I patients with significant ventral brain stem compression where a combined anterior and posterior decompression was considered necessary. We report two patients who underwent transoral odontoidectomy with preservation of the anterior arch of the atlas and suboccipital craniectomy with C1 laminectomy followed by C1-C2 arthrodesis. Preservation of the anterior arch of the atlas in conjunction with C1-C2 arthrodesis stabilizes the occipito-atlanto-axial segments while conserving more cervical mobility as compared to an occipitocervical fusion.

Craniocervical junction fusions in patients with hindbrain herniation and syringohydromyelia

OBJECT

Patients with hindbrain herniation or the so-called Chiari malformation Type I (CM-I) and/or syringohydromyelia are treated with dorsal decompression alone; however, a small percentage of patients with other associated abnormalities require concomitant dorsal craniocervical junction (CCJ) fusion. The authors surveyed the indications for CCJ fusions in this population.

METHODS

A retrospective review of University of Iowa medical records and radiographs obtained between 1996 and 2005 was performed. Inclusion criteria encompassed patients with diagnoses of CM-I and/or syringohydromyelia requiring dorsal CCJ fusions, and others with CCJ abnormalities who had CM-I and/or syringohydromyelia.

RESULTS

Two hundred thirty-four patients were identified, all of whom were symptomatic at presentation. Their ages ranged from 2.5 to 86 years; 33% of the patients were < 16 years of age. Patients were categorized as follows, with some being assigned to > 1 category: Group I, congenital or acquired CCJ abnormalities with reducible bone compression (25% of patients); Group II, previous anterior CCJ/upper brainstem decompression (44%); Group III, occipitocervical complex instability with CM-I and/or syringohydromyelia but without CCJ bone abnormalities requiring adjunctive posterior fossa decompression (26%); and Group IV, musculoligamentous instability, either from pathological states or from muscle dehiscence from repeated posterior fossa procedures (14%). Instrumentation was used in 96% of patients, with all 96% receiving semirigid fixation with titanium loop and sublaminar cables; all fusion constructs incorporated autologous bone. At last follow-up evaluation, fusion was radiographically complete in 97%, and symptom improvement was seen in 92%.

CONCLUSIONS

Dorsal CCJ fusions are required in patients with CM-I and/or syringohydromyelia who have concomitant CCJ abnormalities (Groups I and II). A definite group (CM-I and/or syringohydromyelia) without bone abnormality exists (Groups III and IV). This may be due to muscle weakness secondary to a high syrinx.

Aneurysmal subarachnoid hemorrhage in young adults: a gender comparison study

Aneurysmal subarachnoid hemorrhage is uncommon in young adults. The aim of this study was to compare clinical characteristics of ruptured aneurysms between males and females in the third or fourth decade of life. We retrospectively investigated 301 patients who underwent surgery for ruptured cerebral aneurysms over 6 years. Among them, 53 patients were aged between 20-39 years. Clinical characteristics and related variables were compared between genders. In general, there was a favorable outcome in either gender (84.9%). There was a higher incidence of multiplicity and intraoperative rupture in females, as well as a significant difference in aneurysm location between genders (p=0.030, p=0.014, and p=0.027 respectively). Overall outcome was not different between the two groups. These results suggest that aneurysm formation may differ between genders.

Delayed rupture of pre-existing cerebral aneurysm in a young patient with minor head trauma

An intracranial saccular aneurysm is not commonly diagnosed in a patient with head injury. We present a patient with a history of minor head trauma and a CT scan of the brain revealing minimal subarachnoid hemorrhage 17 days prior to admission, complaining of severe headache, dysarthria and focal right limb seizures 3 hours prior to admission. A traumatic aneurysm was suspected based on clinical history and radiological findings including hematoma in the falx region on a CT scan of the brain and an aneurysm of the pericallosal artery on magnetic resonance angiography and four-vessel cerebral angiography. However, at craniotomy, an intracranial non-traumatic saccular aneurysm at the bifurcation of the pericallosal artery was found. The patient recovered fully after successful clipping the aneurysm.

The pediatric Chiari I malformation: a review

BACKGROUND

Both the diagnosis and treatment regimens for the Chiari I malformation (CIM) are varied and controversial. The present paper analyzes the literature regarding this form of hindbrain herniation in regard to definition, anatomy, pathobiology, symptoms, findings, treatment, and outcomes.

DISCUSSIONS

Appropriate literature germane to the CIM is reviewed and discussed. There is variation in the reported anatomy, outcome, and treatment for children with CIM. Based on the literature, most patients have preoperative symptoms or findings (e.g., syringomyelia) improve no matter what surgical technique is utilized. However, standardized treatment paradigms based on randomized controlled studies are still necessary to elucidate the optimal selection and treatment criteria.

High re-bleeding rate in young adults after subarachnoid haemorrhage from giant aneurysms

Low re-bleeding rates within the first 14 days of aneurysmal subarachnoid haemorrhage are reported in young patients. Furthermore, re-bleeding rate for giant aneurysms does not exceed 20% according to the literature. Our own clinical impression is that the re-bleeding rate seems to be much higher in giant aneurysms than reported, particularly in young patients. The aim of this study was to evaluate re-bleeding rate after subarachnoid haemorrhage following rupture of giant aneurysms in a younger population. We reviewed records of 23 patients who were treated in our institution for subarachnoid haemorrhage from giant aneurysms between 1994 and 2003. By definition, the aneurysms were larger than 25 mm in diameter. Five patients were younger than 40 years of age at the time of the aneurysmal subarachnoid haemorrhage. All younger patients (<40 years of age) showed re-bleeding after the first subarachnoid haemorrhage within the first 14 days of the initial event. In four patients (20%) older than 40 years at the time of the haemorrhage re-bleeding could be observed within the first 14 days of subarachnoid haemorrhage. We can confirm the re-bleeding rate of approximately 20% in patients suffering from subarachnoid haemorrhage (SAH) in the group of patients older than 40 years of age. However, younger patients seem to be at much higher risk of re-bleeding from giant aneurysms.

Isolated atlantal stenosis in a patient with idiopathic growth hormone deficiency, and Klippel-Feil and Duane's syndromes

OBJECTIVE AND IMPORTANCE

Isolated atlantal stenosis is very rare with less than ten cases reported, mostly in adult Asians; however, this pathology should be recognized by the neurosurgeon. An unusual case of this rare clinical entity is reported in conjunction with multiple other anomalies.

CLINICAL PRESENTATION

We report a Caucasian girl with symptomatic stenosis of the first cervical vertebrae who presented with episodes of loss of tone with subsequent falling, facial cyanosis, urinary incontinence, hand weakness, and difficulties with swallowing. This patient also had the diagnoses of Duane's and Klippel-Feil syndromes, and idiopathic growth hormone deficiency. In addition, this patient was found to have retroflexion of the odontoid process, which further compromised the spinal canal. Flexion-extension radiographs failed to identify cervical spine instability.

INTERVENTION

Following suboccipital craniectomy and the removal of the posterior arch of the atlas, the patient's symptoms were resolved and her urinary incontinence improved.

CONCLUSIONS

We theorize that our case represents a variant of Wildervanck syndrome. Further case reports are necessary to verify that isolated atlantal stenosis is a component of this constellation of findings. Furthermore, our case demonstrates that degenerative changes of the spine are not necessary for the production of symptoms in cases of isolated stenosis of the atlas.

Subarachnoid hemorrhage: neurointensive care and aneurysm repair

Aneurysmal subarachnoid hemorrhage (SAH) is often a neurologic catastrophe. Diagnosing SAH can be challenging, and treatment is complex, sophisticated, multidisciplinary, and rarely routine. This review emphasizes treatment in the intensive care unit, surgical and endovascular therapeutic options, and the current state of treatment of major complications such as cerebral vasospasm, acute hydrocephalus, and rebleeding. Outcome assessment in survivors of SAH and controversies in screening of family members are discussed.