Symptomatic Chiari Malformation Research Articles

Familial Chiari malformation: a systematic review and illustrative cases.

Chiari malformations (CMs) are a group of congenital or acquired disorders characterized by hindbrain overcrowding into an underdeveloped posterior cranial fossa. CM is considered largely sporadic-however, there exists growing evidence of transmissible genetic underpinnings. The purpose of this systematic review of all familial studies of CM was to investigate the existence of an inherited component and provide recommendations to manage and monitor at-risk family members. This paper includes the following: 1) a unique case report of dizygotic twins who presented at the Toronto Western Hospital Spinal Cord Clinic with symptomatic CM type 1 (CM-1) and syringomyelia; and 2) a systematic review of familial CM. The EMBASE and MEDLINE databases were searched on June 27, 2023, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Only articles in the English language concerning the diagnosis of CM in > 1 human family member presented as a case study, case series, or literature review were included. Among the 29 articles included in the final analysis, a total of 34 families with CM were analyzed. An average of 3 cases of CM were found per family among all generations. Eighty-one cases (88%) reported CM-1, whereas the other 11 (12%) cases reported either CM-0, CM-1.5, or tonsillar ectopia. A syrinx was present in 37 (54%) cases, with 14 (38%) of these patients also reporting a skeletal abnormality, the most common comorbidity. Most family members diagnosed with CM were siblings (18; 35%), followed by monozygotic twins/triplets (12; 23%). Patients most often presented with headaches, sensory disturbances, or generalized symptoms. Overall, there exists mounting evidence for a hereditary component of CM. It is unlikely to be explained by a classic mendelian inheritance pattern, but is rather a polygenic architecture influenced by variable penetrance, cosegregation, and entirely nongenetic factors. For first-degree relatives of those affected by CM, the authors' findings may influence clinicians to conduct closer clinical and radiographic monitoring, promote patient education, and consider earlier genetic testing.

The impact of neurosurgical technique on the short- and long-term outcomes of adult patients with Chiari I malformation

ObjectiveThis study is aimed to compare and evaluate any differences in clinical and radiological outcomes of different operative techniques of cranio-cervical decompression (CCD) performed in adults with symptomatic Chiari malformation type I (CM-1) within a single tertiary neurosurgical center. MethodsA retrospective review using the Hospital theatre management system (ORSOS) and records of patients who underwent CCD for CM-1 between January 2011 and October 2019 was performed.Patients were divided in three cohorts according to the operative technique used: an extradural osteo-ligamentous decompression (BD), BD followed by dural opening either without duraplasty (DOWD) or plus duroplasty (DOPD). The primary clinical outcome was measured by utilizing the Chicago Chiari Outcome Scale (CCOS). Syrinx outcome was measured on post-op MRI. Statistical analysis was performed using IBM SPSS 24 with α = 0.05. Results67 adults underwent 69 CCD: 10 BD, 29 DOWD and 30 DOPD. Median follow-up was 47.3 months (Interquartile Range (IQR) 26.3–73.7). Patients who underwent DOPD had a shorter median hospital stay (p-value 0.001), fewer unplanned readmissions (p-value 0.015), a higher median CCOS (p-value 0.001) and a lower post-operative complications rate (p-value 0.001) compared to patients who underwent DOWD. BD revealed a 40 % failure rate and was ineffective in cases with syringomyelia. ConclusionBetter clinical outcomes, lower complication risk, and short duration of hospital stay were associated with patients who underwent dural opening with augmentative watertight duraplasty. Bony decompression alone despite being a very safe technique, does not appear to be reliable and effective in controlling and relieving the clinical symptoms and the syringomyelia of adult patients with CM-1.

Experience with revision craniovertebral decompression in adult patients with Chiari malformation type 1, with or without syringomyelia

Background Craniovertebral decompression is performed for symptomatic Chiari malformation type 1, with or without syringomyelia. In a few patients the symptoms and/or syrinx persist or recur, in which case revision surgery may be offered. The aim of this study was to examine the cause of failure of primary surgery and to assess the outcomes for revision cranio-vertebral decompression. Methods We retrospectively reviewed all revision cranio-vertebral decompressions performed in our centre over an eighteen-year period. A total of 35 patients were identified (23 females; 12 males). Twenty patients had isolated Chiari malformation type 1 and a further fifteen had associated syringomyelia. The mean follow up period was 4-years (range:1–12 years). Results The mean time to revision was 7 years after the primary surgery. The commonest operative finding was that of dense arachnoid scar tissue, obstructing movement of CSF across the craniovertebral junction. Overall, 32 of the 35 patients reported improvement after surgery, including all 15 patients with syringomyelia. Improvement was maintained in the longer term in more than two thirds of those patients who underwent revision craniovertebral decompression. Conclusions Failure of primary craniovertebral decompression for Chiari malformation most often results from the formation dense scar tissue at the operation site, obstructing CSF movement. Revision cranio-vertebral decompression can provide early symptomatic relief in most patients and this benefit is sustained in at least two thirds of cases, in the medium term at least. Patients with concomitant syringomyelia appear to derive most benefit from revision surgery.

Failed Foramen Magnum Decompression in Chiari I Malformation Is Associated With Failure to Restore Normal Intracranial Compliance: An Observational Cohort Study.

The standard treatment for symptomatic Chiari malformation (CM) I is foramen magnum decompression (FMD) to facilitate cerebral spinal fluid flow through the foramen magnum, improve intracranial compliance, and alleviate symptoms (commonly headache). This procedure has a variable success rate, with a significant proportion of patients having persistent symptoms after surgery. To investigate intracranial pressure (ICP) hydrodynamics in symptomatic surgery-naïve patients with CM I and symptomatic patients who have had prior FMD. We undertook a retrospective, observational cohort study, extracting data from our departmental ICP database. Patients with untreated ("Virgin") Chiari malformations (VCM), patients with previous "failed" FMD (ie, with persistent classical Chiari symptoms) (fFMD) and a normal control group, all with existing continuous ICP monitoring date were included. Median ICP (mICP) and median pulse amplitude (mPA) were compared between the groups. A total of 33 CM patients (22 VCM and 11 fFMD) and 42 normal controls were included for analysis. mICP did not differ significantly between the normal control, VCM, and fFMD groups. mPA in the VCM and fFMD groups was significantly higher than the control group (P<.01 and P<.05, respectively). In this cohort, patients with persistent symptoms after FMD have persistently impaired intracranial compliance, similar to patients who have not undergone surgery at all when compared with a control group. The reasons for this are not clear, and further research is required to establish the causation and optimum management for failed FMD.

A Combinatorial Approach with Cerebellar Tonsil Suspension to Treating Symptomatic Chiari Malformation Type I in Adults: A Retrospective Study

Primary Chiari malformations (CMs) are congenital defects of the skull base and brain. Among the 4 CM types, type I (CM-I) occurs most frequently and may cause somatosensorimotor, autonomic and vision symptoms. Presently, posterior fossa decompression alone (PFD) or with duraplasty (PFDD) and cerebellar tonsil (CbT) shrinkage tactics are standard treatments, albeit inherent issues. There has been no report on devising CbT suspension (CTS) to manage CM-I. 1) To design a CTS protocol that can be used with CbT coagulation (CTC) and PFDD; 2) to evaluate the regimen for feasibility, safety, and efficacy in a retrospective study; and 3) to obtain data for planning prospective studies to validate PFDD+ CTC+ CTS as a novel approach to treating adult CM-I. PFDD + CTC + CTS (n= 17), PFDD + CTC (n= 13), and PFDD (n= 12) were performed for 42 adult patients (age range, 18-55 years; female:male = 27:15) following a balanced study design. Neck Disability Index (NDI), Chicago Chiari Outcome Scale (CCOS), and /magnetic resonance imaging/computed tomography were used to determine postsurgery outcomes for approximately 20 months. Comparing to PFDD + CTC or PFDD, patients receiving PFDD + CTC +CTS operation exhibited significantly improved group average NDI (10.72 ± 3.95%; P= 0.007), CbT elevation distance (7.06 ± 2.42 mm; P < 0.001, Kruskal-Wallis test; 55.7 ± 25.4% higher than the presurgery level; P < 0.001, analysis of variance), and syringomyelia syrinx retraction (P= 0.009, analysis of variance). The PFDD + CTC + CTS regimen appeared to be safe and potentially more efficacious in patients with CM-I evaluated for the period, relative to PFDD+ CTC or PFDD treatment. Future prospective studies were warranted.

Management of Chiari malformation in syndromic and nonsyndromic craniosynostosis

OBJECTIVEAlthough the association between Chiari malformation (CM) and craniosynostosis is well recognized, management remains controversial. There are differences in the clinical course of CM in syndromic craniosynostosis (SC) patients and nonsyndromic craniosynostosis (NSC) patients. Still unclear is whether cranial expansion surgery, foramen magnum decompression (FMD), or both should be conducted and when the appropriate timing of surgery should be. Here, the authors retrospectively reviewed the clinical data at their institution to investigate the optimal management of CM associated with SC and NSC.METHODSThe authors retrospectively analyzed the clinical records of 163 children with craniosynostosis who underwent surgical treatment at the National Center for Child Health and Development between April 2002 and May 2018.RESULTSTwelve (10%) of 119 children with NSC and 14 (31.8%) of 44 children with SC were radiologically diagnosed with CM. The median age at which CM was radiologically diagnosed was 7 months. Of the 12 NSC patients with CM, 1 (8%) was symptomatic with gait disturbance. This patient underwent FMD following expansion surgery. Of the 14 SC patients with CM, 8 (57.1%) were symptomatic with central sleep apnea. For SC patients with symptomatic CM, cranial expansion surgery alone was conducted in 2 cases, FMD was conducted after cranial expansion in 4 cases, and FMD was conducted first and additional expansion surgery was then conducted in 2 cases. In all cases, symptoms of CM improved after completing this series of surgeries. Regarding patients with asymptomatic CM, cranial expansion surgery alone was performed, and none of the patients showed symptoms of CM thereafter in both SC and NSC cases.CONCLUSIONSMultiple surgeries tend to be necessary for symptomatic CM in both SC and NSC, while no patient with asymptomatic CM became symptomatic after cranial expansion surgery.

PedsQL for prediction of postoperative patient-reported outcomes following Chiari decompression surgery.

The purpose of this study is to determine if the preoperative Pediatric Quality of Life Inventory (PedsQL) score is predictive of short- and intermediate-term PedsQL outcomes following Chiari decompression surgery. The utility of preoperative patient-reported outcomes (PROs) in predicting pain, opioid consumption, and long-term PROs has been demonstrated in adult spine surgery. To the best of the authors' knowledge, however, there is currently no widely accepted tool to predict short-, intermediate-, or long-term outcomes after pediatric Chiari decompression surgery. A prospectively maintained database was retrospectively reviewed. Patients who had undergone first-time decompression for symptomatic Chiari malformation were identified and grouped according to their preoperative PedsQL scores: mild disability (score 80-100), moderate disability (score 60-79), and severe disability (score < 60). PedsQL scores at the 6-week, 3-month, and/or 6-month follow-ups were collected. Preoperative PedsQL subgroups were tested for an association with demographic and perioperative characteristics using one-way ANOVA or chi-square analysis. Preoperative PedsQL subgroups were tested for an association with improvements in short- and intermediate-term PedsQL scores using one-way ANOVA and a paired Wilcoxon signed-rank test controlling for statistically different demographic characteristics when appropriate. A total of 87 patients were included in this analysis. According to their preoperative PedsQL scores, 28% of patients had mild disability, 40% had moderate disability, and 32% had severe disability. There was a significant difference in the prevalence of comorbidities (p = 0.009) and the presenting symptoms of headaches (p = 0.032) and myelopathy (p = 0.047) among the subgroups; however, in terms of other demographic or operative factors, there was no significant difference. Patients with greater preoperative disability demonstrated statistically significantly lower PedsQL scores at all postoperative time points, except in terms of the parent-reported PedsQL at 6 months after surgery (p = 0.195). Patients with severe disability demonstrated statistically significantly greater improvements (compared to preoperative scores) in PedsQL scores at all time points after surgery, except in terms of the 6-week and 6-month PROs and the 6-month parent-reported outcomes (p = 0.068, 0.483, and 0.076, respectively). Patients with severe disability, as assessed by the PedsQL, had lower absolute PedsQL scores at all time points after surgery but greater improvement in short- and intermediate-term PROs. The authors conclude that the PedsQL is an efficient and accurate tool that can quickly assess patient disability in the preoperative period and predict both short- and intermediate-term surgical outcomes.

PedsQL for Prediction of Postoperative Patient-Reported Outcomes following Chiari Decompression Surgery

Background and Hypothesis: Chiari malformation type I (CM-I) is a common pediatric disorder in which the cerebellar tonsils herniate the foramen magnum with associated spinal symptoms. The purpose of this study is to determine if the preoperative Pediatric Quality of Life Inventory (PedsQL) score is predictive of intermediate-term PedsQL outcomes following Chiari decompression surgery. The utility of preoperative patient-reported outcomes (PROs) to postoperative PROs has been previously demonstrated in adult spine surgery. However, to our knowledge, there is currently no widely accepted tool to predict short-, intermediate-, or long-term outcomes after pediatric Chiari decompression surgery.&#x0D; Project Methods: A prospectively maintained database was retrospectively reviewed. Patients who underwent first-time decompression for symptomatic Chiari malformation were identified and grouped by their preoperative PedsQL scores: mild disability (score 80–100), moderate disability (score 60–80); and severe disability (score &lt; 60). PedsQL outcomes were collected at 6-week, 3-month, and 6-month follow-up. Preoperative PedsQL subgroups were tested for an association with demographic, perioperative characteristics, and improvements between groups by one-way ANOVA, chi-square, or Wilcoxon signed rank test, where appropriate.&#x0D; Results: The postoperative patient- and parent-reported PedsQL values were significantly different between all three groups at 6-weeks, 3-months, and 6-months after surgery (p &lt; 0.05), except at the 6-month timepoint for parent-reported outcomes (p = 0.111). Patients with higher preoperative disability demonstrated statistically significant greater improvements (compared to preoperative score) in parent-reported PedsQL at all timepoints after surgery, except at the 6-month parent-reported outcomes (p = 0.133).&#x0D; Conclusion: Patients with worse preoperative disability, as assessed by PedsQL, experienced lower absolute PedsQL scores at all timepoints after surgery but had greater improvement in short- and intermediate-term PROs. We conclude that PedsQL is an efficient and accurate tool that can quickly assess patient disability in the preoperative period and predict both short-term and long-term surgical outcomes.

Surgical Treatment in Symptomatic Chiari Malformation Type I: A Series of 25 Adult Patients Treated with Cerebellar Tonsil Shrinkage.

The variety of symptoms and radiological findings in patients with Chiari malformation typeI makes both the indication for surgery and the technical modality controversial. We report our 5-year experience, describing our technique and critically evaluating the clinical results. Between 2012 and 2016, 25 patients (15 female and 10 male; mean age 39.2years) underwent posterior fossa decompression for Chiari malformation typeI. Their clinical complaints included headache, nuchalgia, upper limb weakness or numbness, instability, dizziness and diplopia. Syringomyelia was present in 12 patients (48%). Suboccipital craniectomy was completed in all cases with C1 laminectomy and shrinkage of the cerebellar tonsils by bipolar coagulation; duraplasty was performed with a suturable dura substitute. Gratifying results were observed in our series. Symptoms and signs were resolved in 52% of patients, and 20% of patients had an improvement in their preoperative deficits. The symptoms of six patients (24%) were essentially unchanged, and one patient (4%) deteriorated despite undergoing surgery. Generally, patients with syringomyelia on magnetic resonance imaging (MRI) showed less symptomatic improvement after surgery. The syrinx disappeared in seven of 12 patients, and complications occurred in threepatients (12%). Cerebellar tonsil reduction and restoration of cerebrospinal fluid (CSF) circulation provided clinical improvement and a stable reduction in the syrinx size in the vast majority of treated patients, with a low rate of complications.

Headache, Chiari I malformation and foramen magnum decompression.

With increasing use of MRI, more patients are being diagnosed with Chiari I malformation (CM1), many of whom are asymptomatic. When symptoms are present, headache is the most frequent presenting feature, although symptoms can be variable. The purpose of this review is to help primary care clinicians better understand the relationship between an individual's presenting symptoms and the presence of radiographic CM1, and to describe the expected outcomes for patients who undergo decompression surgery. Recent literature has shown that asymptomatic patients with CM1 tend to have a benign natural history. For symptomatic Chiari malformation, headache is the most common presenting symptom and the majority of patients that present with headache will have symptom improvement after foramen magnum decompression. This improvement is most reliable for patients with classic Chiari-type headache, which are described as occipital or cervical and tussive in nature, but has also been shown in patients with atypical headaches who have undergone surgery. CM1 is a common radiographic finding and associated symptoms can be variable. The relevance of this finding to a particular patient and need for intervention must be made on an individual basis.

Chiari decompression outcomes using ligamentum nuchae harvest and duraplasty in pediatric patients with Chiari malformation type I.

OBJECTIVE The choice of graft material for duraplasty in decompressions of Chiari malformations remains a matter of debate. The authors present a detailed technique for harvesting ligamenta nuchae, as well as the clinical and radiographic outcomes of this technique, in a case series. METHODS The authors conducted a retrospective study evaluating the outcomes of Chiari malformation type I decompression and duraplasty in children aged 0-18 years at a single institution from 2013 to 2016. They collected both intraoperative and postoperative variables and compared them qualitatively to published data. RESULTS During the study period, the authors performed 25 Chiari malformation decompressions with ligamentum nuchae graft duraplasties. Of the 25 patients, 10 were females, and the mean age at surgery was 8.6 years (range 13 months to 18 years). The median operative time was 163 minutes (IQR 152-187 minutes), with approximately 10 minutes needed by a resident surgeon to harvest the graft. The mean length of stay was 3 nights (range 2-6 nights), and the mean follow-up was 12.6 months (range 0.5-43.5 months). One patient (4%) developed a CSF leak that was repaired using an oversewing patch. There were no postoperative pseudomeningoceles or infections. Of the 19 patients presenting with a syrinx, imaging showed improvement in 10 (53%) and 8 (42%) had stable syrinx size on imaging. Of 16 patients presenting with a symptomatic Chiari malformation, 14 (87.5%) experienced resolution of symptoms and in 1 (4%) symptoms remained the same. One patient (4%) presented with worsening syrinx and symptoms 1.5 months after initial surgery and underwent repeat decompression. CONCLUSIONS The authors describe a series of clinical and imaging outcomes of patients who underwent Chiari malformation decompression and duraplasty with a harvested ligamentum nuchae. The rates of postoperative CSF leak are similar to established techniques of autologous and artificial grafts, with similarly successful outcomes. Further study will be needed with larger patient cohorts to more directly compare duraplasty graft outcomes.

313 Morphometric and Volumetric Comparison of Symptomatic and Asymptomatic Chiari Malformation Type I

Abstract INTRODUCTION Chiari malformation type I (CMI) is typically defined by a cerebellar tonsil position 5 mm or more below foramen magnum. Low cerebellar tonsil position is a frequent incidental finding, even in asymptomatic individuals. Non-specific symptoms such as headache and neck pain are common in those with low tonsil position and in those with normal tonsil position, leading to uncertainty regarding appropriate management for many patients with low tonsil position and non-specific symptoms. Since cerebellar tonsil position is not strictly correlated with typical CMI symptoms, we sought to determine if other 2D morphometric or 3D volumetric measurements on MRI could distinguish asymptomatic from symptomatic CMI patients. METHODS We retrospectively analyzed 102 pediatric patients from the University of Michigan clinical CMI database. All patients in this database have cerebellar tonsil position at least 5 mm below foramen magnum. Fifty-one symptomatic and 51 asymptomatic patients were matched for age at diagnosis, sex, tonsil position, and tonsil morphology. Five 2D anatomic MRI measurements and four 3D volumetric measurements of posterior fossa and CSF sub-volumes on MRI were measured. RESULTS &gt;There were no significant differences observed between symptomatic and asymptomatic CMI patients related to basilar impression (−5.9 mm vs. −7.0 mm; P = 0.026), tentorium length (50.3 mm vs. 51.0 mm; P = 0.537), supraoccipital length (39.4 mm vs. 42.6 mm; P = 0.055), clivus-tentorium distance (52.0 mm vs. 52.1 mm; P = 0.964), clivus-torcula distance (81.5 mm vs. 83.3 mm; P = 0.257), total posterior fossa volume (PFV; 183.4 mL vs. 190.6 mL; P = 0.250), caudal PFV (152.5 mL vs. 159.8 mL; P = 0.256), fourth ventricle volume to caudal PFV ratio (0.0140 vs. 0.0136; P = 0.649), or CSF volume to caudal PFV ratio (0.071 vs. 0.061; P = 0.138). CONCLUSION We did not identify any 2D or 3D measurements that could reliably distinguish pediatric patients with symptoms attributable to CMI from those with asymptomatic CMI.

The association between the pulse pressure gradient at the cranio-cervical junction derived from phase-contrast magnetic resonance imaging and invasively measured pulsatile intracranial pressure in symptomatic patients with Chiari malformation type 1.

In symptomatic Chiari malformation type 1 (CMI), impaired intracranial compliance (ICC) is associated with an increased cranio-spinal pulsatile pressure gradient. Phase-contrast magnetic resonance imaging (MRI) represents a non-invasive modality for the assessment of the pulse pressure gradient at the cranio-cervical junction (CCJ). We wished to explore how the MRI-derived pulse pressure gradient (MRI-dP) compares with invasively measured pulsatile intracranial pressure (ICP) in CMI, and with healthy controls. From phase-contrast MRI of CMI patients and healthy controls, we computed cerebrospinal fluid (CSF) flow velocities and MRI-dP at the CCJ. We assessed bidirectional flow and compared the flow between the anterior and the posterior subarachnoid space at the CCJ. We computed total intracranial volume (ICV), ventricular CSF volume (VV), and posterior cranial fossa volume (PCFV). We analyzed the static and pulsatile ICP scores from overnight monitoring in CMI patients. Five CMI patients and four healthy subjects were included. The CMI group had a significantly larger extent of tonsillar ectopia, smaller PCFV, and a smaller area of CSF in the FM. The pulsatile ICP (mean ICP wave amplitude, MWA) was abnormally increased in 4/5 CMI patients and correlated positively with MRI-dP. However, the MRI-dP as well as the CSF flow velocities did not differ significantly between CMI and healthy subjects. Moreover, bidirectional flow was observed in both CMI as well as healthy subjects, with no significant difference. In symptomatic CMI patients, we found a significant association between the pulse pressure gradient at the CCJ derived from phase-contrast MRI and the pulsatile ICP (MWA) measured invasively. However, the MRI-dP was close to identical in CMI patients and healthy subjects. Moreover, the CSF flow velocities at the CCJ and the occurrence of bidirectional flow were not different in CMI patients and healthy individuals. Further studies are required to determine the diagnostic role of phase-contrast MRI in CMI patients.

Modified Surgical Technique for Chiari Malformation

Craniectomy with or without cervical laminectomy is a well-recognized treatment option for patients with symptomatic Chiari malformation. However, performing craniectomy removes the protection of the suboccipital cranial bone while laminectomy may limit cervical spine movement. We undertook a retrospective study of seventeen patients who underwent conventional craniectomy and cervical laminectomy or cranioplasty alone for correction of Chiari malformation. The objective was to present cinical outcome and complications when the Chiari malformation was corrected by conventional craniectomy/ laminectomy or craniotomy alone. In the craniotomy group with eleven patients, the inside of the suboccipital bone was resurfaced prior to replacing it thereby creating space for the cerebrospinal fluid to flow after adhesionolysis and careful resection/ shrinkage of subpial tonsils without performing laminectomy. Craniectomy and C1-C2 laminectomy was done in six patients as per standard procedure. At a variable followup period of 10 years after the surgery, we did not observe any difference in clinical outcome between the two groups. The resolution of syrinx was 54.5 % in the craniotomy group as compared to 66.7% in the craniectomy/ laminectomy group, while it persisted unchanged in one patient in each group. CSF leak was noted in 2 patients in each group. Reduction of symptoms like headache, neck pain or paresthesia showed reduction in intensity in all patients except paresthesia that persisted in 1 patient of the craniotomy group. The finding of this study suggests that performing craniotomy alone is as effective as craniectomy/ laminectomy in terms of outcome and relief of signs and symptoms of Chiari malformation.

Cephalometric oropharynx and oral cavity analysis in Chiari malformation Type I: a retrospective case-control study.

OBJECTIVE Traditionally, Chiari malformation Type I has been related to downward herniation of the cerebellar tonsils as a consequence of an underdeveloped posterior cranial fossa. Although the common symptoms of Chiari malformation Type I are occipital headaches, cervical pain, dizziness, paresthesia, and sensory loss, patients often report symptoms related to pharyngeal dysfunction such as choking, regurgitation, dysphagia, aspiration, chronic cough, and sleep disorders. In addition, tracheal intubation is often difficult in these patients. The purpose of this study was to analyze the morphological features of the oropharynx and oral cavity in patients with Chiari malformation Type I to help identify underlying anatomical anomalies leading to these debilitating symptoms. METHODS Seventy-six adult patients with symptomatic Chiari malformation Type I with cerebellar tonsillar descent greater than 5 mm below the foramen magnum and a small posterior cranial fossa and 49 sex-matched controls were selected to perform a retrospective case-control MRI-based morphometric study in a tertiary hospital. Eleven linear and areal parameters of the oropharyngeal cavity on midsagittal T1-weighted MRI were measured and the average values between patients and control cohorts were compared. Correlations between variables showing or approaching statistical significance in these structures and posterior cranial fossa measurements related with the occipital bone were sought. RESULTS Significant differences were detected for several oropharynx and oral cavity measures in the patient cohort, primarily involving the length and thickness of the soft palate (p = 9.5E-05 and p = 3.0E-03, respectively). A statistically significant (p < 0.01) moderate correlation between some of these variables and posterior cranial fossa parameters was observed. CONCLUSIONS The existence of structural oropharyngeal and oral cavity anomalies in patients with Chiari malformation Type I was confirmed, which may contribute to the frequent occurrence of respiratory and deglutitory complications and sleep disorders in this syndrome.

Intracranial Hypertension in a Patient with a Chiari Malformation Accompanied by Hyperthyroidism.

The Chiari malformation is an infrequently detected congenital anomaly characterized by the downward displacement of the cerebellum with a tonsillar herniation below the foramen magnum that may be accompanied by either syringomyelia or hydrocephalus. Surgery, such as foramen magnum decompression, is indicated for a symptomatic Chiari malformation, although an incidental lesion may be followed-up without further treatment. Infrequently, increased intracranial pressure emerges due to hyperthyroidism. A nineteen-year-old girl visited our outpatient clinic presented with a headache, nausea and vomiting. A brain and spinal magnetic resonance image study (MRI) indicated that the patient had a Chiari I malformation without syringomyelia or hydrocephalus. An enlarged thyroid gland was detected on a physical examination, and serum markers indicated Graves' disease. The patient started anti-hyperthyroid medical treatment. Subsequently, the headache disappeared after the medical treatment of hyperthyroidism without surgical intervention for the Chiari malformation. A symptomatic Chiari malformation is indicated for surgery, but a surgeon should investigate other potential causes of the symptoms of the Chiari malformation to avoid unnecessary surgery.

Chiari 1 Malformation Presenting as Central Sleep Apnea during Pregnancy: A Case Report, Treatment Considerations, and Review of the Literature.

Purpose: Chiari malformation (CM) type-1 frequently causes obstructive or central sleep-disordered breathing (SDB) in both adults and children, although SDB is relatively rare as a presenting manifestation in the absence of other neurological symptoms. The definitive treatment of symptomatic CM is surgical decompression. We report a case that is, to our knowledge, a novel manifestation of central sleep apnea (CSA) due to CM type-1 with severe exacerbation and initial clinical presentation during pregnancy.Methods: Case report from tertiary care comprehensive sleep medicine center with literature review of SDB manifestations associated with CM type-1. PubMed search was conducted between January 1982 and October 2013.Results: We report a 25-year-old woman with severe CSA initially presenting during her first pregnancy that eventually proved to be caused by CM type-1. The patient was successfully treated preoperatively by adaptive servoventilation (ASV), with effective resolution of SDB following surgical decompression, and without recurrence in a subsequent pregnancy. Our literature review found that 58% of CM patients with SDB had OSA alone, 28% had CSA alone, 8 (10%) had mixed OSA/CSA, and 6 (8%) had hypoventilation. Of CM patients presenting with SDB, 50% had OSA, 42% had CSA, 8% had mixed OSA/CSA, and 10.4% had hypoventilation. We speculate that CSA may develop in CM patients in whom brainstem compression results in excessive central chemoreflex sensitivity with consequent hypocapnic CSA.Conclusion: Chiari malformation type-1 may present with a diversity of SDB manifestations, and timely recognition and surgical referral are necessary to prevent further neurological deficits. ASV therapy can effectively manage CSA caused by CM type-1, which may initially present during pregnancy.

The Comparative Morphometric Study of the Posterior Cranial Fossa : What Is Effective Approaches to the Treatment of Chiari Malformation Type 1?

ObjectiveThe 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.MethodsWe 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.ResultsThe 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.ConclusionWe 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.

Blue rubber bleb naevus syndrome and chiari malformation: high risk of peroperative haemorrhage.

Blue rubber bleb naevus syndrome is an uncommon disorder whereby patients possess cutaneous vascular malformations. Cranial malformations have been rarely reported in the literature. We report the first ever case of a patient with blue rubber bleb naevus syndrome (BRBNS), who was found to have a symptomatic Chiari malformation and prominent subcutaneous vascular malformations in communication with the intracranial venous sinuses. In our case, a routine operation for Chiari malformation was complicated by significant blood loss. The operative hazards are presented along with suggested peri-operative management strategies when carrying out neurosurgical operations on patients with BRBNS. A brief literature review is included.

Posterior fossa volume increase after surgery for Chiari malformation Type I: a quantitative assessment using magnetic resonance imaging and correlations with the treatment response

The aim of this paper was to measure the posterior fossa (PF) volume increase resulting from a given-sized occipital craniectomy in Chiari malformation Type I surgery and to analyze its correlations with the PF size and the treatment response, with the perspective of tailoring the amount of bone removal to the patient-specific PF dimensions. Between January 2005 and June 2006, 11 adult patients with symptomatic Chiari malformation Type I underwent a standardized PF decompression. A prospective evaluation with clinical examination, functional grading, and MR imaging measurement protocols was performed pre- and postoperatively. A method is reported for the measurement of PF volume (PFV) after surgery. The degree of PFV increase was compared with the preoperative size of the PF and with the clinical outcome. All 11 patients improved postoperatively, with complete and partial recovery in 4 and 7 patients, respectively. No postoperative complication occurred after a mean follow-up period of 45 months. The mean relative increase in PFV accounted for 10% (range 1.5%-19.7%) of the initial PFV; the increase was greater in cases in which the PF was small (r = -0.52, p = 0.09) and the basiocciput was short (r = -0.37, p = 0.2). A statistically significant positive correlation was found between the degree of PFV increase and the treatment response (p = 0.014); complete recovery was observed with a PFV increase of 15% and partial recovery with an increase of 7%. The treatment response is significantly influenced by the degree of PFV increase, which is dependent on the size of the PF and the extent of the craniectomy, suggesting that the optimal patient-specific PFV increase could be predicted on the basis of preoperative MR imaging and enhancing the perspective that the craniectomy size could be tailored to the individual PFV.