Chiari I malformation: classification and management

A Prospective Study of CSF Flow Dynamics Across Foramen Magnum in Adult Chiari Malformation/Syringomyelia Complex and its Clinical Correlation with Outcomes after Surgery

Introduction  Chiari I malformation refers to cerebellar tonsillar descent below the foramen magnum and is frequently associated with syringomyelia. Prior cerebrospinal fluid (CSF) flow studies correlated the clinical severity of these lesions with general flow velocity or bulk flow at the foramen magnum; however, these techniques have not assessed the effect on surgical outcomes. The study aims to present clinical and radiological factors and CSF flow parameters (pre- and postoperative) that affect the surgical outcome. Materials and Methods  The institutional ethics committee approved the study. We collected the prospective clinical data, including pre- and postoperative symptoms. Functional grades were determined along with the change in clinical improvement based on clinical examination notes, the change in functional grade was calculated, and the radiologic data were analyzed according to the degree of clinical improvement. The surgical procedure included suboccipital bony decompression with duroplasty. Patients were followed up at 1 month, 3 months, and 1 year. Results  There were a total of 25 patients. The mean age of the patients was 45.52 ± 13.37 years, with 40% being males and 60% being females. After the surgery, there was a significant increase in the anterior and posterior CSF flows at the foramen magnum. Most had a resolution in the headache and sensory symptoms, while the lower cranial nerve and motor symptoms had a minor resolution at follow-up. Age, sex, and headache do not correlate with the outcome or syrinx improvement. Motor power in the lower limb (preintervention) and syrinx shape (preintervention) were significantly associated with the variable "anterior flow at the foramen magnum" (preintervention; p  < 0.05). Average flow, cervicomedullary angle (postintervention), sensory symptom progression, and CSF flow change anterior to the foramen magnum were significantly associated with the variable "anterior flow at the foramen magnum" (postintervention; p  < 0.05). Conclusion  Even after surgery, persistent foramen magnum CSF outflow obstruction has a robust negative correlation with the outcome. The Chiari outcome predictability index has shown a significant correlation with patient outcomes and can be used to inform patients about the expected outcome. The results of the present study will be helpful in stratifying patients according to their desired outcomes.

A Novel Craniocervical Junction Compression Severity Index-Based Grading System for Multidirectional Quantification of the Biomechanics at Foramen Magnum of Chiari Malformation Type I

Objective  This study aimed to establish a novel grading system, based on the craniovertebral junction compression severity index (CVJCSI) for multidirectional quantification at the foramen magnum plane for Chiari malformation type I (CMI). Methods  The CVJCSI grading system was established to stratify patients based on the ventral (modified clivoaxial angle < 138°), dorsal (tonsil herniation), and central (brainstem herniation) CVJ (craniovertebral junction) compression, the CVJCSI grading system was established to stratify patients. The optimal surgical method for each grade was recommended by intragroup comparisons regarding the efficacy of the three operations. Finally, according to the CVJCSI grading system, a prospective validation trial was performed and surgically treated for internal validation. Results  Based on the retrospective study ( n  = 310), the CVJCSI included six grades: I: syrinx alone without compression; II: dorsal compression; III: dorsal and central compression; IV: ventral compression; V: dorsal and ventral compression; and VI: ventral, dorsal, and central compression. Among all available variables, only the CVJCSI and surgical methods significantly affected the CCOS. The CCOS scores, overall and for each CVJCSI grade, increased in the prospective cohort ( n  = 42) compared with that in the retrospective analysis. Conclusions  The CVJCSI can be used to stratify CMI patients. The higher the CVJCSI grade, the more severe the CVJ compression and the worse posterior fossa deformity. Meanwhile, the CVJCSI was negatively correlated with the CCOS. The lower the CVJCSI grade, the better the response to surgery, and the less-invasive surgical procedures were warranted. Finally, the prospective cohort study validated the proposed CVJCSI-based surgical protocols.

The Chiari Malformations: A Bibliometric Analysis of the 100 Most Cited Articles

OBJECTIVE

The Chiari malformations present heterogeneous entities, raising many questions regarding their natural history, pathophysiology, treatment options, and prognosis. Bibliometric analyses have emerged as a method to assess the impact of articles in current clinical practice.

METHODS

The most cited articles were identified via Scopus Library by using the keywords "Chiari," "Arnold-Chiari," and "Chiari malformation." The 100 most cited articles were then assembled and analyzed in detail.

RESULTS

The top 100 articles yielded a mean of 155,28 citations per article, ranging from 87 to 896 citations, and from 1.63 to 38.96 per year. Years of publications ranged from 1950 to 2015. Oakes was the most cited author (n = 7), followed by Tubbs and Milhorat. The country with the highest cited articles was the United States (n = 63), followed by the United Kingdom (n = 6), Italy (n = 5), Spain (n = 5), Japan (n = 4), and Germany (n = 3). Neurosurgery is the journal with the most highly cited articles (n = 21), followed by Journal of Neurosurgery (n = 19). Most articles focused on Chiari malformation type I (n = 83). The topic discussed most often was imaging (n = 63), followed by the evaluation of treatment outcome (n = 58), clinical signs and symptoms (n = 57), and the role of surgery (n = 56).

CONCLUSIONS

The present bibliometric analysis provides a succinct appraisal of the most cited articles concerning Chiari malformation, allowing a deeper insight in this area and its main influential articles with their impact on current clinical practice and future research.

Foramen Magnum Decompression for Chiari Malformation Type 1: Is There a Superior Surgical Technique?

BACKGROUND

Foramen magnum decompression is a common operation used to treat Chiari malformation. There are different surgical techniques; however, some are anecdotally more effective than others. Our aim was to determine whether there is a superior technique in relation to revision rates, presence of persistent postoperative headache and nausea, and syrinx reduction.

METHODS

This was a retrospective analysis of foramen magnum decompressions performed between 2012 and 2017 for Chiari 1 in a single institution. Three types of operations were performed: 1) bony decompression alone; 2) bony decompression with durotomy and dura left open; 3) bony decompression with opening of dura and duraplasty. We compared postoperative symptoms and revision rates between these 3 operations.

RESULTS

In 168 patients, 185 foramen magnum decompressions were performed. Among the 168 primary operations, in 66 the dura was not opened, in 86 the dura was opened without a duraplasty, and in 16 a duraplasty was performed. Of 185 operations, 17 were revision surgery. For primary procedures, the revision rates were 12 (18%) where the dura was not opened, 4 (5%) where the dura was left open, and 1 (6%) when duraplasty was performed. Severe postoperative headache and nausea occurred in 2 (3%) patients where the dura was not opened, 4 (25%) patients after primary duraplasty, and 64 (74%) patients after primary durotomy.

CONCLUSIONS

In this study, rate of revision surgery was highest in patients who had bony decompression without dural opening. Rate of postoperative headache and nausea was highest in the durotomy group. Overall duraplasty had the best results.

Downbeat nystagmus: a clinical review of diagnosis and management

PURPOSE OF REVIEW

This review will extensively cover the clinical manifestations, causes, diagnostic evaluation, and management strategies of downbeat nystagmus (DBN).

RECENT FINDINGS

Historically, MRI to assess for structural lesions at the cervicomedullary junction has been the primary diagnostic test in the evaluation of DBN since the 1980s. In recent years, there is increasing awareness of nonstructural causes of DBN including gluten ataxia, nutritional deficiencies, and paraneoplastic syndromes, among others. Medical management with aminopyridines has become first-line therapy in addition to disease-specific therapies.

SUMMARY

DBN is a common form of acquired nystagmus and the differential diagnosis remains broad, including both benign and potentially fatal causes. For practical purposes, the causes can be categorized as structural vs. nonstructural with MRI as the ideal, initial diagnostic study to differentiate the two. General therapeutic options include pharmacotherapy to enhance Purkinje cell function, strabismus surgery or prisms to shift null points, and behavioural changes. Disease-specific treatment is necessarily broad, though a significant proportion of patients will be idiopathic.

Fourth ventricle roof angle as a measure of fourth ventricle bowing and a radiographic predictor of brainstem dysfunction in Chiari malformation type I

OBJECTIVE

Chiari malformation type I (CM-I) is a congenital and developmental abnormality that results in tonsillar descent 5 mm below the foramen magnum. However, this cutoff value has poor specificity as a predictor of clinical severity. Therefore, the authors sought to identify a novel radiographic marker predictive of clinical severity to assist in the management of patients with CM-I.

METHODS

The authors retrospectively reviewed 102 symptomatic CM-I (sCM-I) patients and compared them to 60 age-matched normal healthy controls and 30 asymptomatic CM-I (aCM-I) patients. The authors used the fourth ventricle roof angle (FVRA) to identify fourth ventricle "bowing," a configuration change suggestive of fourth ventricle outlet obstruction, and compared these results across all three cohorts. A receiver operating characteristic (ROC) curve was used to identify a predictive cutoff for brainstem dysfunction. Binary logistic regression was used to determine whether bowing of the fourth ventricle was more predictive of brainstem dysfunction than tonsillar descent, clival canal angle, or obex position in aCM-I and sCM-I patients.

RESULTS

The FVRA had excellent interrater reliability (intraclass correlation 0.930, 95% CI 0.905-0.949, Spearman r2 = 0.766, p < 0.0001). The FVRA was significantly greater in the sCM-I group than the aCM-I and healthy control groups (59.3° vs 41.8° vs 45.2°, p < 0.0001). No difference was observed between aCM-I patients and healthy controls (p = 0.347). ROC analysis indicated that an FVRA of 65° had a specificity of 93% and a sensitivity of 50%, with a positive predictive value of 76% for brainstem dysfunction. FVRA > 65° was more predictive of brainstem dysfunction (OR 5.058, 95% CI 1.845-13.865, p = 0.002) than tonsillar herniation > 10 mm (OR 2.564, 95% CI 1.050-6.258, p = 0.039), although increasing age was also associated with brainstem dysfunction (OR 1.045, 95% CI 1.011-1.080, p = 0.009). A clival canal angle < 140° (p = 0.793) and obex below the foramen magnum (p = 0.563) had no association with brainstem dysfunction.

CONCLUSIONS

The authors identified a novel radiographic measure, the FVRA, that can be used to assess fourth ventricular bowing in CM-I and is more predictive of brainstem dysfunction than tonsillar herniation. The FVRA is easy to measure, has excellent interrater variability, and can be a reliable universal radiographic measure. The FVRA will be useful in further describing CM-I radiographically and clinically by identifying patients more likely to be symptomatic as a result of brainstem dysfunction.

Type I Chiari Malformation Without Concomitant Bony Instability: Assessment of Different Surgical Procedures and Outcomes in 73 Patients

OBJECTIVE

Posterior fossa decompression is the treatment of choice in type 1 Chiari malformation (CM-1) without bony instability. Although surgical fixation has been recommended by a few authors recently, comparative studies to evaluate these treatment strategies using objective outcome tools are lacking.

METHODS

Seventy-three patients with pure CM-1 (posterior fossa bony decompression [PFBD], n = 21; posterior fossa bony and dural decompression [PFBDD], n = 40; and posterior fixation [PF], n = 12) underwent a postoperative outcome assessment using Chicago Chiari Outcome Score (CCOS). Logistic regression analysis detected predictors of an unfavorable outcome.

RESULTS

Minimally symptomatic patients generally underwent a PFBD while most of the clinically severe patients underwent a PFBDD (p = 0.049). The mean CCOS score at discharge was highest in the PF (12.0 ± 1.41) and lowest in PFBDD group (10.98 ± 1.73, p = 0.087). Patients with minimal preoperative clinical disease severity (adjusted odds ratio [AOR], 4.58; 95% confidence interval [CI], 1.29-16.31) and PFBDD (AOR, 7.56; 95% CI, 1.70-33.68) represented risks for an unfavorable short-term postoperative outcome. Though long-term outcomes (CCOS) did not differ among the 3 groups (p = 0.615), PFBD group showed the best long-term improvements (mean follow-up CCOS, 13.71 ± 0.95), PFBDD group improved to a comparable degree despite a poorer short-term outcome while PF had the lowest scores. Late deteriorations (n = 3, 4.1%) occurred in the PFBDD group.

CONCLUSION

Minimally symptomatic patients and PFBDD predict a poor short-term postoperative outcome. PFBD appears to be a durable procedure while PFBDD group is marred by complications and late deteriorations. PF does not provide any better results than posterior fossa decompression alone in the long run.

Endoscopic Transnasal Odontoidectomy for Ventral Decompression of the Craniovertebral Junction: Surgical Technique and Clinical Outcome in a Case Series of 19 Patients

BACKGROUND

Abnormalities and pathologies of the craniovertebral junction as well as space-occupying lesions of the odontoid process can result in myelopathy symptoms. A staged procedure with posterior stabilization and anterior transnasal endoscopic decompression is recently considered a less invasive alternative to the transoral approach. We present a considerably large case series focused on the operative technique and the long-term neurological clinical outcome.

OBJECTIVE

To determine the safety and efficacy of odontoidectomy performed via an endoscopic transnasal approach.

METHODS

We retrospectively reviewed all patients treated in our neurosurgical department from January 2009 to January 2020. Demographics, pre- and postoperative clinical status, and operative technique and complications were extracted and analyzed.

RESULTS

In total, 22 transnasal operations were performed in 19 patients from January 2009 to January 2020. All but one patient underwent posterior C1-C2 instrumentation prior to the anterior transnasal computed tomography (CT)-navigated full-endoscopic decompression. The median duration of symptoms before surgery was 3 mo. Complications occurred in 1 patient who died from septic organ failure because of his initial diagnosis of osteomyelitis. Postoperative CT imaging showed sufficient decompression in 16 patients, and 3 patients underwent a transnasal endoscopic re-decompression (16%).

CONCLUSION

Transnasal endoscopic odontoidectomy presents a safe procedure with a satisfying clinical and radiological postoperative outcome.

Posterior fossa decompression with or without duraplasty for patients with chiari type I malformation and basilar impression: a meta-analysis

BACKGROUND

To compare clinical effect and safety between posterior fossa decompression with duraplasty (PFDD) and posterior fossa decompression without duraplasty (PFD) in treatment of Chiari type I malformation and basilar impression.

METHODS

A comprehensive computer search was conducted from 2000 to 2019. The quality assessment was performed by the QUADAS-2 tool. The clinical value of comparison between PFDD and PFD was evaluated by using the pooled estimate of sensitivity and specificity. In addition, sensitivity analysis and bias analysis were applied to ensure the accuracy of the results.

RESULTS

Finally, 468 patients were enrolled in 6 studies and ultimately met the eligibility criteria. The PFDD and PFD groups were 282 and 186, respectively. The meta-analysis showed no significant difference in the Chicago Chiari Outcome Scale (COSS score) (MD = 0.14, 95% CI [-0.23, 0.50], P = 0.47; P = heterogeneity = 0.86, I² = 0%). Meanwhile, Significant difference existed in length of stay (MD = -1.08, 95% CI [-1.32, -0.84], P = 0.001; heterogeneity P < 0.000001, I² = 85%) and complications (OR = 0.35, 95%CI [0.20, 0.62], P = 0.0003; P for Heterogeneity = 0.04, I² = 56%).

CONCLUSION

PFD is a more efficient and safer therapy than PFDD in the treatment of Chiari type I malformation with basilar impression.

Treatment emergent obstructive sleep apnea after Chiari surgery: A case report

Patients with Chiari type I malformation may also present with sleep disordered breathing mainly central sleep apnea. Here, we report a patient with Chiari I malformation referred to our clinic because of snoring and sleep disordered breathing. He was a 28-year-old man referred to us for evaluation of snoring. An overnight polysomnography revealed central sleep apnea. On further evaluation of central sleep apnea, the patient found to have Chiari malformation type I on brain MRI. The patient developed obstructive sleep apnea after surgery for Chiari malformation. Accordingly, pap titration was performed for the patient's obstructive sleep apnea. In patients with central sleep apnea comprehensive evaluation of predisposing causes is required. Lesions of central nervous system including Chiari malformation should not be overlooked. Furthermore, after treatment of central sleep apnea follow up PSG is warranted to confirm newly emerged sleep breathing disorder such as obstructive sleep apnea.

Family History in Chiari Malformation Type I: Presentation and Outcome

BACKGROUND

Some patients with Chiari malformation type I (CM-1) present with a positive family history of CM-1, the significance of which remains unknown. We aimed to study whether family history affects the clinical presentation characteristics and surgical outcome of adult patients with CM-1.

METHODS

A database of adult patients with CM-1 presenting between January 1, 2006 and December 31, 2018 was used. Presenting characteristics were compared between patients with and without a family history (first, second, or third degree) of CM-1. Among surgically treated patients, perioperative and long-term outcomes, with favorable outcome defined as a Chiari Outcome Scale score ≥14, were compared between patients with and without CM-1 family history. All patients completed at least 6 months of postoperative follow-up.

RESULTS

The database consisted of 233 adult patients with CM-1, 14 of whom (6%) had a positive family history. Presenting characteristics were comparable between patients with and without a positive family history. A total of 150 patients underwent suboccipital decompression, 12 of whom (8%) had a positive family history. After a mean follow-up of 1.9 years, patients with a family history of CM-1 were significantly less likely to achieve a favorable outcome (odds ratio, 0.22; 95% confidence interval, 0.06-0.78; P = 0.019) while controlling for several covariates. Post hoc analysis showed that the difference was most significant when looking at pain symptoms.

CONCLUSIONS

Presentation characteristics are comparable between patients with and without a family history of CM-1. Patients with a positive family history may be less likely to respond favorably to suboccipital decompression.

The SHORE Score: A Novel Predictive Tool for Improvement After Decompression Surgery in Adult Chiari Malformation Type I

BACKGROUND

A practical scoring system predicting significant improvement after surgical decompression in adult Chiari malformation type I (CM-1) based on validated outcome measures is lacking. We aimed to develop a simple score and improvement calculator to facilitate the decision making process in symptomatic CM-1 patients.

METHODS

We evaluated adult CM-1 patients who presented to our institution between September 2006 and September 2018 and underwent surgical decompression. Previously treated patients were excluded. Univariable analysis and multivariable logistic regression were conducted to derive an optimal model predictive of improvement on last follow-up as measured by the Chicago Chiari Outcome Scale. A score was derived using the beta coefficients of the model, and predictive performance was assessed using receiver operating curves with bootstrap validation. Finally, a web-based improvement calculator was deployed.

RESULTS

The surgical cohort consisted of 149 adult CM-1 patients, of which 100 (67%) experienced significant clinical improvement (Chicago Chiari Outcome Scale ≥14) after a mean follow-up of 1.9 years. The final model predictive of significant clinical improvement consisted of headache with Valsalva (odds ratio [OR] = 2.39; P = 0.030), nonwhite race (OR = 2.57; P = 0.041), absence of visual symptoms (OR = 2.59; P = 0.015), syrinx absence (OR = 1.59; P = 0.315), and increased odontoid retroflexion (OR = 2.82; P = 0.009). The score was termed SHORE, which summarizes the model's predictive factors, each assigned 1 point. The model had an area under the curve of 0.754 with an optimism-correct value of 0.721. A calculator was deployed under: https://jhuspine2.shinyapps.io/SHORE_score/.

CONCLUSIONS

The score and calculator can serve as supplements to clinical decision making by providing realistic and personalized expectations of postoperative outcome.

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

OBJECTIVE

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.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

Somatosensory and motor evoked potentials during correction surgery of scoliosis in neurologically asymptomatic Chiari malformation-associated scoliosis: A comparison with idiopathic scoliosis

OBJECTIVES

To analyze the somatosensory evoked potentials (SEPs) and motor evoked potentials (MEPs) in neurologically asymptomatic Chiari malformation-associated scoliosis (CMS) patients with and without syringomyelia as compared with those in idiopathic scoliosis (IS) ones, and to identify whether the deformities have impacts on the neurophysiological monitoring.

PATIENTS AND METHODS

This study included neurologically asymptomatic CMS patients undergoing posterior correction surgery between January 2010 and January 2016. IS patients were involved as control group and a subgroup of age- and height-matched IS patients were selected. The age, standing height and Cobb angles of main curve were measured. The SEPs latency and amplitude, MEPs amplitude, and the rate of abnormal SEPs pathologic change were compared between CMS and IS patients using independent-sample t-test and Chi-square test.

RESULTS

Sixty CMS patients and 210 IS patients were included. There was no difference between CMS patients and IS or matched IS patients in SEPs latency and amplitude, MEPs amplitude or rate of abnormal SEPs (p > 0.05). Forty-eight CMS patients concurrent with syringomyelia were associated with higher Cobb angle of main curve and lower SEPs amplitude than those without syringomyelia (p < 0.05). No significant difference was found between CMS patients with and without syringomyelia in age, height, SEPs latency, MEPs amplitude or rate of abnormal SEPs (p > 0.05).

CONCLUSION

Neurologically asymptomatic CMS patients showed similar absolute values of neurophysiological monitoring with IS patients. The syringomyelia in CMS indicated more severe curvature and lower SEPs amplitude even after posterior fossa decompression.

Chiari malformation and types of basilar invagination with/without syringomyelia

BACKGROUND

Craniometric studies document different subtypes of craniocervical junction malformations (CCJM). Here, we identified the different types and global signs and symptoms (SS) that correlated with these malformations while further evaluating the impact of syringomyelia.

METHODS

Prospective data concerning SS and types of CCJM were evaluated in 89 patients between September 2002 and April 2014 using Bindal's scale.

RESULTS

The mean Bindal's scores of each type of CCJM were Chiari malformation (CM) = 74.6, basilar invagination Type 1 (BI1) = 78.5, and BI Type 2 (BI2) = 78. Swallowing impairment and nystagmus were more frequently present in the BI patients. Symptomatic burdens were higher in patients with syringomyelia and included weakness, extremity numbness, neck pain, dissociated sensory loss, and atrophy.

CONCLUSION

There were no statistically significant differences in SS between the different CCJM types. BI patients had more swallowing and nystagmus complaints versus CM patients, but there were no significant differences in clinical SS between BI1 and BI2 patients. Notably, those with attendant syringomyelia had a higher SS burden.

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.

Significance of Modified Clivoaxial Angles in the Treatment of Adult Chiari Malformation Type I

OBJECTIVE

To investigate the influence of modified clivoaxial angle (MCAA) on the surgical planning and outcome in adult patients with Chiari malformation type I.

METHODS

Clinical data of 268 adult patients undergoing posterior fossa decompression without (PFD) or with duraplasty (PFDD) or with resection of tonsils (RT) for Chiari malformation type I over 10 years were reviewed retrospectively, with outcome evaluated by Chicago Chiari Outcome Scale (CCOS) score. By means of receiver operating characteristic curve, the threshold of MCAA was calculated to stratify the patients.

RESULTS

MCAA was positively correlated with CCOS score. In the MCAA ≤ 127° group (n = 57) with severe ventral cervicomedullary compression (VCMC), CCOS score of PFD, PFDD, and RT was 11.00, 11.06, and 12.42 (P < 0.05), respectively. In the 127° < MCAA ≤ 138° group (n = 87) with moderate VCMC, CCOS score of PFD, PFDD, and RT was 11.71, 12.72, and 13.00 (P < 0.01), respectively. In the MCAA > 138° group (n = 124) with mild or no VCMC, CCOS score of PFD, PFDD, and RT was 13.19, 13.90, and 13.67 (P < 0.05), respectively. The mean MCAA increased by 4.4° postoperatively (P < 0.05), which was positively associated with syringomyelia shrinkage.

CONCLUSIONS

MCAA may play a role in guiding the surgical treatment and predicting the prognosis in adult CMI patients. The larger the MCAA, the less invasive surgery is preferred with higher CCOS. PFDD should be the first choice in patients with mild or no VCMC (MCAA >138°) and RT in patients with moderate VCMC (127° < MCAA ≤ 138°). For patients with severe VCMC (MCAA ≤ 127°), RT could be considered as the primary surgery with awareness of the possible insufficiency of posterior decompression alone.

Craniometrical imaging and clinical findings of adult Chiari malformation type 1 before and after posterior fossa decompression surgery with duraplasty

Background: Posterior fossa decompression both with and without duraplasty are accepted treatments for symptomatic adult patients with Chiari Malformations Type 1 (CM-1). There is still debate of the superiority of one technique over the other. The purpose of this study was to determine the clinical and craniometrical imaging outcomes of a series of patients who underwent posterior fossa decompression with duraplasty. Materials and methods: All adult patients with symptomatic CM-1 operated at a single institution with a minimum of 6 months follow-up were enrolled prospectively. Clinical outcomes and craniometrical parameters based upon MR imaging pre- and post-surgery were analyzed. Results: A series of 33 consecutive patients who met the inclusion criteria were enrolled; mean age of 33.93 ± 10 years (range 14-56 years). The most common preoperative complaint was headache. The most common clinical sign was sensory dysfunction which was relieved or improved in 63% of patients. The mean syringomyelia size had a significant reduction after the surgery (p = .01). The mean tonsillar descent also had significant reduction (p = .00). The mean McRae line length before the surgery and after that were 33.4 and 53.1 mm respectively that this change was not statistically significant (p = .42). The odontoid process parameters had no significant changes after surgery. Conclusions: Posterior fossa decompression surgery with duraplasty can improve both clinical and imaging outcomes such as syringomyelia size and tonsillar descent for patients with symptomatic CM-1. However, no significant difference was found in craniometrical parameters before and after the surgery.

Sequential Enlargement of Posterior Fossa After Duraplasty for Chiari Malformation Type 1

Objective

There are several material options for duraplasty in surgery for foramen magnum decompression (FMD). We retrospectively analyzed surgical results and the impact of sequential alteration of posterior fossa (PF) size in patients with Chiari malformation type 1 after duraplasty using local fascia.

Methods

The patients with Chiari malformation type 1 who underwent FMD with duraplasty using local fascia at our institution between 2004 and 2015 were included in the study. Some pediatric patients who underwent FMD without duraplasty and patients with insufficient follow-up data were excluded. Improvement of clinical signs, regression of syrinx, and temporal alteration of PF size were analyzed with perioperative magnetic resonance imaging. Postoperative clinical outcomes were evaluated at the final follow-up using the Chicago Chiari Outcome Scale. Correlations between the PF size alteration and size of dural patch or Chicago Chiari Outcome Scale were statistically analyzed.

Results

Twelve patients were included in this study. The mean age of the patients was 31.9 (range, 18–48) years. Syrinx was incorporated in 11 patients and regressed postoperatively in all patients. The PF was significantly enlarged sequentially over time (P < 0.05). The degree of enlargement was positively correlated with size of the fascial patch (r = 0.540). Postoperative clinical outcomes at final follow-up were positively correlated with the degree of PF enlargement (r = 0.678).

Conclusions

The PF was enlarged sequentially over time after duraplasty using local fascia. The degree of enlargement was positively correlated with the size of the fascial patch and the likelihood of a favorable postoperative outcome.

Chiari Malformation Type 1: A Systematic Review of Natural History and Conservative Management

BACKGROUND

Chiari malformation type 1 (CM-1) is a variation of hindbrain development that can sometimes occur in asymptomatic individuals. Conventional treatment is surgical decompression, but little is known about the natural history of patients who do not undergo surgical management. This information is critical to determine how these patients should be managed. We conducted a systematic literature review to determine the natural history of CM-1, particularly in patients who did not undergo surgery and in asymptomatic individuals, to help patients and physicians determine when surgery is likely to be beneficial.

METHODS

The literature search was performed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines using the electronic databases PubMed, Scopus, Cochrane Library, and Web of Science. Inclusion and exclusion criteria were predefined.

RESULTS

In symptomatic patients who did not undergo surgery, headaches and nausea often improved, whereas ataxia and sensory disturbance tended not to improve spontaneously. Of patients, 27%-47% had an improvement in symptoms after 15 months, and 37%-40% with cough headache and 89% with nausea who were managed nonoperatively improved at follow-up. Most asymptomatic individuals with CM-1 remained asymptomatic (93.3%) even in the presence of syringomyelia.

CONCLUSIONS

The natural history of mild symptomatic and asymptomatic CM-1 in adults is relatively benign and nonprogressive; the decision to perform surgical decompression should be based on severity and duration of a patient's symptoms at presentation. It is reasonable to observe a patient with mild or asymptomatic symptoms even in the presence of significant tonsillar descent or syringomyelia.

Chiari I malformation with underlying pseudotumor cerebri: Poor symptom relief following posterior decompression surgery

INTRODUCTION


 Pseudotumor cerebri (PTC) patients exhibit clear clinical signs and symptoms of higher intracranial pressure (ICP) without ventricular enlargement or mass lesions. The clinical picture of patients with PTC can sometimes be similar to that of Chiari Malformation type I (CMI). There is some evidence that Chiari I malformation and PTC may coexist, which raises the question of whether PTC is an idiopathic disease or a complication of posterior decompression surgery-treatment of choice for Chiari I malformation.

PRESENTATION OF CASES

A retrospective review of electronic medical records of patients diagnosed with PTC at the University of Toledo Medical Center (UTMC) was performed. The objective was to determine whether PTC patients had a concurrent diagnosis of Chiari I malformation and whether the diagnosis of PTC occurred before or after posterior decompression surgery. Out of the 8 eligible patient medical records reviewed, 5 patients diagnosed with PTC had undergone posterior decompression surgery for Chiari I malformation at anywhere from several days to three years prior to being diagnosed with PTC. The diagnosis of PTC was based on temporary symptomatic relief following lumbar puncture which also showed elevated CSF opening pressures. Finally, a VP shunt was placed in each of the 5 patients to relieve the elevated intracranial pressure which resulted in the complete resolution of the patients' symptoms.

DISCUSSION

Our study focuses on patients who were diagnosed with and treated for CMI then reported back to the clinic within several days to three years complaining of symptoms of headache. Upon re-presenting to the clinic, a CSF flow study was performed which showed normal flow of CSF. Then, these patients underwent a lumbar puncture which demonstrated an elevated opening pressure (and ICP) and a temporary relief of the headache with lumbar drainage. A VP shunt was placed for each patient to treat for PTC, and the patients' headaches were relieved.

CONCLUSION

This study suggests that the presence of Chiari I malformation in a patient conceals the symptoms of PTC which may become apparent following posterior decompression surgery. Other possibilities could be that the patients are misdiagnosed for Chiari I malformation when they are in fact suffering from PTC, or that PTC is a complication of surgery.

Type I Chiari malformation presenting orthostatic syncope who treated with decompressive surgery

Chiari malformations are a congenital anomaly of the hindbrain. The most common, Chiari malformation type I (CM-I), is characterized by herniation of the cerebellar tonsils extending at least 3 mm below the plane of the foramen magnum. Consequently, CM-I is associated with hydrocephalus and symptoms involving compression of the cervicomedullary junction by ectopic tonsils. Several studies have reported the clinical symptoms associated with CM-I, including suboccipital headache, weakness in the upper extremities, facial numbness, loss of temperature sensation, ataxia, diplopia, dysarthria, dysphagia, vomiting, vertigo, nystagmus, and tinnitus. Syncope is one of the rarest presentations in patients with CM-I. There are many hypotheses regarding the causes of syncope in patients with CM-I; however, the mechanisms are not clearly understood. Although surgical decompression for CM-I in patients with syncope has yielded good clinical results in some studies, such cases are rarely reported. We report a case of orthostatic syncope in a patient with CM-I who was treated with surgical intervention.

Tonsillar contusion associated with benign tonsillar ectopia following minor head trauma

PURPOSE

The relationship between tonsil position and symptomatic cerebellar contusion is unclear. To date, there are no reports of symptomatic traumatic brain injury associated with benign tonsillar ectopia. Reported cases are limited to prominent cerebellar tonsillar displacement by ≥5 mm (i.e., Chiari malformations).

METHODS

The authors describe a case of symptomatic concussion in a toddler with unusual computerized tomography (CT) presentation and incidental finding of benign tonsillar ectopia, hemorrhagic contusion of the tonsils, blood-brain barrier (BBB) disruption and delayed atrophy shown using magnetic resonance imaging (MRI) studies. The radiological presentation and the clinical challenges are discussed through a review of the literature.

CONCLUSION

This case suggests that damage to cerebellar structures is not limited only to overt tonsillar herniation. Benign tonsillar ectopia may predispose to cerebellar contusion even after minor concussion and thus has a clinical significance. The current paradigm viewing only noticeable tonsillar herniation as a risk factor for hindbrain injury should be revisited.

Clinical significance of changes in pB-C2 distance in patients with Chiari Type I malformations following posterior fossa decompression: a single-institution experience

OBJECT The coexistence of Chiari malformation Type I (CM-I) and ventral brainstem compression (VBSC) has been well documented, but the change in VBSC after posterior fossa decompression (PFD) has undergone little investigation. In this study the authors evaluated VBSC in patients with CM-I and determined the change in VBSC after PFD, correlating changes in VBSC with clinical status and the need for further intervention. METHODS Patients who underwent PFD for CM-I by the senior author from November 2005 to January 2013 with complete radiological records were included in the analysis. The following data were obtained: objective measure of VBSC (pB-C2 distance); relationship of odontoid to Chamberlain's, McGregor's, McRae's, and Wackenheim's lines; clival length; foramen magnum diameter; and basal angle. Statistical analyses were performed using paired t-tests and a mixed-effects ANOVA model. RESULTS Thirty-one patients were included in the analysis. The mean age of the cohort was 10.0 years. There was a small but statistically significant increase in pB-C2 postoperatively (0.5 mm, p < 0.0001, mixed-effects ANOVA). Eleven patients had postoperative pB-C2 values greater than 9 mm. The mean distance from the odontoid tip to Wackenheim's line did not change after PFD, signifying postoperative occipitocervical stability. No patients underwent transoral odontoidectomy or occipitocervical fusion. No patients experienced clinical deterioration after PFD. CONCLUSIONS The increase in pB-C2 in patients undergoing PFD may occur as a result of releasing the posterior vector on the ventral dura, allowing it to relax posteriorly. This increase appears to be well-tolerated, and a postoperative pB-C2 measurement of more than 9 mm in light of stable craniocervical metrics and a nonworsened clinical examination does not warrant further intervention.

Stereological and Morphometric Analysis of MRI Chiari Malformation Type-1

Objective

In this study, we aimed to investigate the underlying ethiological factors in chiari malformation (CM) type-I (CMI) via performing volumetric and morphometric length-angle measurements.

Methods

A total of 66 individuals [33 patients (20-65 years) with CMI and 33 control subjects] were included in this study. In sagittal MR images, tonsillar herniation length and concurrent anomalies were evaluated. Supratentorial, infratentorial, and total intracranial volumes were measured using Cavalieri method. Various cranial distances and angles were used to evaluate the platybasia and posterior cranial fossa (PCF) development.

Results

Tonsillar herniation length was measured 9.09±3.39 mm below foramen magnum in CM group. Tonsillar herniation/concurrent syringomyelia, concavity/defect of clivus, herniation of bulbus and fourth ventricle, basilar invagination and craniovertebral junction abnormality rates were 30.3, 27, 18, 2, 3, and 3 percent, respectively. Absence of cisterna magna was encountered in 87.9% of the patients. Total, IT and ST volumes and distance between Chamberlain line and tip of dens axis, Klaus index, clivus length, distance between internal occipital protuberance and opisthion were significantly decreased in patient group. Also in patient group, it was found that Welcher basal angle/Boogard angle increased and tentorial slope angle decreased.

Conclusion

Mean cranial volume and length-angle measurement values significantly decreased and there was a congenital abnormality association in nearly 81.5 percent of the CM cases. As a result, it was concluded that CM ethiology can be attributed to multifactorial causes. Moreover, congenital defects can also give rise to this condition.

The Chiari Severity Index: a preoperative grading system for Chiari malformation type 1

BACKGROUND

To develop evidence-based treatment guidelines for Chiari malformation type 1 (CM-1), preoperative prognostic indices capable of stratifying patients for comparative trials are needed.

OBJECTIVE

To develop a preoperative Chiari Severity Index (CSI) integrating the clinical and neuroimaging features most predictive of long-term patient-defined improvement in quality of life (QOL) after CM-1 surgery.

METHODS

We recorded preoperative clinical (eg, headaches, myelopathic symptoms) and neuroimaging (eg, syrinx size, tonsillar descent) characteristics. Brief follow-up surveys were administered to assess overall patient-defined improvement in QOL. We used sequential sequestration to develop clinical and neuroimaging grading systems and conjunctive consolidation to integrate these indices to form the CSI. We evaluated statistical significance using the Cochran-Armitage test and discrimination using the C statistic.

RESULTS

Our sample included 158 patients. Sequential sequestration identified headache characteristics and myelopathic symptoms as the most impactful clinical parameters, producing a clinical grading system with improvement rates ranging from 81% (grade 1) to 58% (grade 3) (P = .01). Based on sequential sequestration, the neuroimaging grading system included only the presence (55% improvement) or absence (74% improvement) of a syrinx ≥6 mm (P = .049). Integrating the clinical and neuroimaging indices, improvement rates for the CSI ranged from 83% (grade 1) to 45% (grade 3) (P = .002). The combined CSI had moderately better discrimination (c = 0.66) than the clinical (c = 0.62) or neuroimaging (c = 0.58) systems alone.

CONCLUSION

Integrating clinical and neuroimaging characteristics, the CSI is a novel tool that predicts patient-defined improvement after CM-1 surgery. The CSI may aid preoperative counseling and stratify patients in comparative effectiveness trials.

Foramen Magnum Decompression and Duraplasty is Superior to Only Foramen Magnum Decompression in Chiari Malformation Type 1 Associated with Syringomyelia in Adults

STUDY DESIGN

Retrospective cohort study.

PURPOSE

To compare surgical results of foramen magnum decompression with and without duraplasty in Chiari malformation type 1 (CM-1) associated syringomyelia (SM).

OVERVIEW OF LITERATURE

The optimal surgical treatment of CM-1 associated with SM is unclear.

METHODS

Twenty-five cases of CM-1 with SM were included. There were 12 patients (48%) in the non-duraplasty group and 13 patients (52%) in the duraplasty group. The rate of improvement, state of postoperative SM size, amount of tonsillar herniation, preoperative symptom duration, complications and reoperation rates were analysed.

RESULTS

The rate of clinical improvement was significantly higher with duraplasty (84.6%) than without (33.3%, p <0.05). The rate of postoperative syrinx regression was significantly higher in the duraplasty group (84.6%) than in the non-duraplasty group (33.3%, p <0.05). One case in the duraplasty group needed a reoperation compared with five cases in the non-duraplasty group (p =0.059).

CONCLUSIONS

Duraplasty is superior to non-duraplasty in CM-1 associated with SM despite a slightly higher complication rate.

Diffusion tensor imaging in cervical syringomyelia secondary to Chiari I malformation: preliminary results

STUDY DESIGN

A prospective observational analysis.

OBJECTIVE

The aim was to perform a quantitative analysis of the neuronal status in cervical syringomyelia secondary to Chiari I malformation (CMI-S) using diffusion tensor imaging.

SUMMARY OF BACKGROUND DATA

Syringomyelia is a common finding in patients with CMI. Conventional imaging techniques frequently fail to assist clinicians in quantitatively assessing the neural damage in these patients.

METHODS

Twenty-three patients with CMI-S (aged 8-25 yr) were prospectively enrolled from April 2012 to August 2013. Sensitivity encoding single-shot echo-planar imaging was used for the sagittal diffusion tensor imaging. Fractional anisotropy (FA) values in the spinal cord were compared between the patients and normal volunteers and further evaluated with respect to syrinx severity and neurological signs/symptoms.

RESULTS

Compared with the normal controls, the FA values were significantly decreased at the level of the syrinx (0.429 ± 0.015 vs. 0.533 ± 0.007; P < 0.001), whereas no significant decreased FA value was measured in the tissue rostral and caudal to the syrinx. Concerning patients with different size of the syrinx, significantly decreased FA values at the syrinx level were observed in patients with a distended syrinx in comparison with those with a nondistended syrinx (0.397 ± 0.013 vs. 0.480 ± 0.018; P < 0.001). Moreover, the FA value at the syrinx level was found to be significantly decreased in the symptomatic group when compared with the nonsymptomatic or control groups (P < 0.05), and there was also a significant difference between the 2 latter groups (P < 0.05).

CONCLUSION

Decreased FA value at the syrinx levels may provide evidence of increased microstructural damage within the spinal cord parenchyma at this area, and changes in this diffusion tensor imaging parameter are significantly related to syrinx size and to the appearance of neurological signs/symptoms.

LEVEL OF EVIDENCE

4.

Pediatric and adult Chiari malformation Type I surgical series 1965-2013: a review of demographics, operative treatment, and outcomes

OBJECT

Chiari malformation Type I (CM-I) is a hindbrain disorder associated with elongation of the cerebellar tonsils, which descend below the foramen magnum into the spinal canal. It occurs in children and adults. Clinical symptoms mainly develop from alterations in CSF flow at the foramen magnum and the common subsequent development of syringomyelia.

METHODS

The authors reviewed English-language reports of pediatric, adult, and combined (adult and pediatric) surgical series of patients with CM-I published from 1965 through August 31, 2013, to investigate the following: 1) geographical distribution of reports; 2) demographics of patients; 3) follow-up lengths; 4) study durations; 5) spectrum and frequency of surgical techniques; 6) outcomes for neurological status, syrinx, and headache; 7) frequency and scope of complications; 8) mortality rates; and 9) differences between pediatric and adult populations. Research and inclusion criteria were defined, and all series that contained at least 4 cases and all publications with sufficient data for analysis were included.

RESULTS

The authors identified 145 operative series of patients with CM-I, primarily from the United States and Europe, and divided patient ages into 1 of 3 categories: adult (>18 years of age; 27% of the cases), pediatric (≤18 years of age; 30%), or unknown (43%). Most series (76%) were published in the previous 21 years. The median number of patients in the series was 31. The mean duration of the studies was 10 years, and the mean follow-up time was 43 months. The peak ages of presentation in the pediatric studies were 8 years, followed by 9 years, and in the adult series, 41 years, followed by 46 years. The incidence of syringomyelia was 65%. Most of the studies (99%) reported the use of posterior fossa/foramen magnum decompression. In 92%, the dura was opened, and in 65% of these cases, the arachnoid was opened and dissected; tonsillar resection was performed in 27% of these patients. Postoperatively, syringomyelia improved or resolved in 78% of the patients. Most series (80%) reported postoperative neurological outcomes as follows: 75% improved, 17% showed no change, and 9% experienced worsening. Postoperative headaches improved or resolved in 81% of the patients, with a statistical difference in favor of the pediatric series. Postoperative complications were reported for 41% of the series, most commonly with CSF leak, pseudomeningocele, aseptic meningitis, wound infection, meningitis, and neurological deficit, with a mean complication rate of 4.5%. Complications were reported for 37% of pediatric, 20% of adult, and 43% of combined series. Mortality was reported for 11% of the series. No difference in mortality rates was seen between the pediatric and adult series.

CONCLUSIONS

Before undergoing surgical treatment for CM-I, symptomatic patients and their families should be given clear information about the success of treatment and potential complications. Furthermore, surgeons may benefit from comparing published data with their own. In the future, operative CM-I reports should provide all details of each case for the purpose of comparison.

Arachnolysis or cerebrospinal fluid diversion for adult-onset syringomyelia? A Systematic review of the literature

OBJECTIVE

To identify surgical practice patterns in the literature for nonpediatric syringomyelia by systematic review and to determine the following: 1) What is the best clinical practice of cerebrospinal fluid (CSF) diversion to maximize clinical improvement or to achieve the lowest recurrence rate? 2) Does arachnolysis, rather than CSF diversion, lead to prolonged times to clinical recurrence?

METHODS

A database search comprising PubMed, Cochrane Register of Controlled Trials, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Scopus, and Cochrane Database of Systematic Reviews was conducted to find pertinent articles on postinfectious, posttraumatic, or idiopathic syringomyelia.

RESULTS

An advanced PubMed search in August 2012 yielded 1350 studies, including 12 studies meeting Oxford Centre for Evidence-Based Medicine criteria for level IV evidence as a case series, with a total of 410 patients (mean age, 39 years). Data on 486 surgeries were collected. Mean follow-up data were available for 10 studies, with a mean follow-up time of 62 months. On regression analysis, increased age had a significant correlation with a higher likelihood of having clinically significant recurrence on mean follow-up (P < 0.05). The use of arachnolysis in surgery was associated with a longer duration until clinically symptomatic recurrence (P = 0.02). Data on mortality were unavailable. The mean number of surgeries per patient across all studies was 1.20 (range, 0.95-2.00).

CONCLUSIONS

With postinfectious and posttraumatic etiologies, arachnolysis was the only surgical treatment to have a statistically significant effect on decreasing recurrence rates. More prospective, randomized, controlled studies are required to reach a clear consensus.

The comparative morphometric study of the posterior cranial fossa : what is effective approaches to the treatment of Chiari malformation type 1?

Objective

The 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.

Methods

We 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.

Results

The 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.

Conclusion

We 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.

The quality of life and psychiatric morbidity in patients operated for Arnold-Chiari malformation type I

BACKGROUND

There are some case reports that highlight the association of Arnold-Chiari malformation (ACM) with psychiatric symptoms. We assessed the association between ACM and psychiatric symptoms and risk factors in terms of psychiatric morbidity and evaluated the quality of life after surgery.

METHODS

This study consisted of sixteen patients who underwent decompression operation at the Department of Neurosurgery of Sisli Etfal Hospital. The MINI plus, Short-Form McGill Pain Questionnaire and WHOQOL-BREF-TR were administered to patients.

RESULTS

About 43.8% of the patients had a psychiatric disorder. About 50% of the patients had co-existing syringomyelia of which 50% with syringomyelia had a psychiatric disorder. Patients with syringomyelia without any psychiatric disorder had significantly lower scores on physical domain of WHOQOL-BREF-TR (p = 0.02) than the patients without syringomyelia and psychiatric disorder. Subjects with a psychiatric disorder had lower scores on four domains of WHOQOL-BREF-TR. The patients with psychiatric diagnoses had significantly higher scores on affective pain index (p = 0.021) and total pain index (p = 0.037) than the patients without any psychiatric disorder.

CONCLUSION

The presence of a psychiatric condition influences not only the physical aspect but also deteriorates the psychological and social relations and environmental aspect. Moreover the presence of a psychiatric disorder increases the perception of pain and causes more discomfort.

Association of increased body mass index with Chiari malformation Type I and syrinx formation in adults

Object

In this paper the authors describe an association between increased body mass index (BMI) and Chiari malformation Type I (CM-I) in adults, as well as its relationship to the development of syringomyelia.

Methods

In the period between January 2004 and December 2011, the senior author reviewed the data for all CM-I patients with or without syringomyelia and neurological deficit. Analyzed factors included clinical status (headaches and neurological signs), radiological characteristics of syringomyelia (diameter and vertical extent of syrinx), BMI, and relationship of age to BMI, syrinx diameter, and vertical extent of syrinx.

Results

Sixty consecutive adults had CM-I, 26 of whom also had syringomyelia. The mean BMI among all patients was 30.35 ± 7.65, which is Class I obesity (WHO), and was similar among patients with or without syringomyelia. Extension of the vertical syrinx was greater in overweight patients (p = 0.027) than in those with a normal body weight. Evidence of de novo syrinx formation was found in 2 patients who gained an average BMI of 10.8 points. After repeated decompression and no change in holocord syrinx width or vertical extent, a reduction in the syrinx was seen after BMI decreased 11.7 points in one individual. No correlation was found between patient age and BMI, age and vertical extension of the syrinx, and age and diameter of the syrinx.

Conclusions

An association between increased BMI and CM-I in adults was recognized. Gaining weight may influence the de novo creation of a syrinx in adults who previously had minimally symptomatic or asymptomatic CM-I, and reducing weight can improve a syrinx after unsuccessful surgical decompression. Therefore, a reduction in body weight should be recommended for all overweight and obese patients with CM-I.

Effectiveness of brace treatment of Chiari malformation-associated scoliosis after posterior fossa decompression: a comparison with idiopathic scoliosis

STUDY DESIGN

Retrospective case-control study.

OBJECTIVE

To evaluate the effectiveness of bracing in patients with Chiari malformation-associated scoliosis (CMS) after posterior fossa decompression (PFD).

SUMMARY OF BACKGROUND DATA

The effectiveness of bracing has been poorly studied in patients with CMS who have undergone PFD.

METHODS

A retrospective study was conducted on 22 patients with CMS who received brace treatment of scoliosis after PFD. Forty-four age- and sex-matched patients with idiopathic scoliosis (IS) who were treated with bracing served as the control group. The bracing outcome was considered a failure if the curve worsened 6° or more; otherwise, the treatment was considered to be successful.

RESULTS

The age and Risser sign were similar between patients with CMS and IS at brace initiation. The initial curve magnitude of patients with CMS (mean, 32.9° ± 6.3°; range, 20°-45°) was marginally significantly larger than that of patients with IS (mean, 29.6° ± 6.4°; range, 20°-45°). Until the final follow-up, a 6° or more worsening of the major curve occurred in 8 patients with CMS (36%) and in 15 patients with IS (34%). Overall, 7 patients with CMS (32%) and 13 patients with IS (30%) underwent spinal fusion surgery. No significant differences were observed between the 2 groups in the surgery rates or the bracing success rates (P > 0.05). In patients with CMS, neither the performance of syringosubarachnoid shunting nor the extent of tonsillar descent correlated with the bracing outcomes, whereas a double major curve pattern was found to be predictive for the failure of bracing.

CONCLUSION

Brace treatment subsequent to PFD is effective in preventing curve progression for 64% of patients with CMS, which is comparable with the rate that is observed in patients with IS. Double major curve pattern may be a risk factor in predicting treatment failure in patients with CMS.

LEVEL OF EVIDENCE

3.

A novel scoring system for assessing Chiari malformation type I treatment outcomes

BACKGROUND

Outcome assessment for the management of Chiari malformation type 1 is difficult because of the lack of a reliable and specific surgical outcome assessment scale. Such a scale could reliably correlate postoperative outcomes with preoperative symptoms.

OBJECTIVE

We developed a novel scoring system and applied it retrospectively to 146 patients treated at our institution in order to create and verify a simple and quantifiable assessment of Chiari outcomes.

METHODS

The Chicago Chiari Outcome Scale (CCOS) uses 4 postoperative outcome categories (pain, nonpain symptoms, functionality, and complications) graded 1 to 4 for a total possible score of 16. As a comparison with current Chiari outcome methodology, each patient was also placed into a gestalt outcome group of "improved," "unchanged," or "worse" (I/U/W). Patients were stratified by CCOS scores and by I/U/W group.

RESULTS

Stratifying patients by total CCOS scores showed that patients who achieved CCOS scores between 13 and 16 were predominantly in the I/U/W improved group (n = 101, 69%); scores between 9 and 12 were predominantly I/U/W unchanged (n = 39, 27%), and scores between 4 and 8 were I/U/W worse (n = 6, 4%). Symptom subscore results provided insight into the specifics of the overall outcome in addition to the more quantitative nature of the 16-point scale.

CONCLUSION

We describe a CCOS that assigns higher scores to patients judged improved by gestalt I/U/W ratings and lower scores to those who were unchanged or worse while defining outcome in 4 specific subcategories. As such, this CCOS should allow for a more unified and quantifiable outcome assessment after Chiari surgery.

Long-term results and complications of the syringopleural shunting for treatment of syringomyelia: a clinical study

BACKGROUND

The use of drains in the treatment of syringomyelia has a simple and immediate appeal. Syringopleural shunting in syringomyelia has produced good short-term results, but limited information is available on long-term effects. We analyzed the complications and long-term outcomes after syringopleural shunting for syringomyelia.

CLINICAL MATERIAL AND METHODS

Fourthy-four patients with large-sized syringomyelia underwent syringopleural shunting because of spinal cord compression between 1992 and 2010 in our clinic. Thirty-two patients had Chiari malformation type I (Group B), and 12 patients were associated with primary parenchymal cavitations (Group A). Their ages ranged from 14 to 71 years. Both craniovertebral decompression and syringopleural shunting were performed on 21 patients, whereas only syringopleural shunting was performed on another 21 patients.

RESULTS

The follow-up period ranged from 1 year to 17 years (mean: 9.1 years). There was no operative mortality. Early postoperative MRI revealed that syringes of 43 patients had collapsed. There were 9 (20.5%) minor complications in 9 patients, including temporary neurological deficits (6), respiratory distress (2) and headache (1). Seven (15.9%) serious complications [permanent neurological deficit (1), shunt migration (2), shunt misplacement (1), spinal instability (1), tethering (1), CSF over drainage (1)] were seen in five patients. Four of them were treated with a secondary operation. Three patients (3/9; 33.3%) who were treated by syringopleural shunt alone (Group B2) required craniovertebral decompression, although the shunt was functional. During long-term follow-up, three patients stabilized, five patients (11.3%) developed a worse neurological condition, and two of these patients died 10 and 7 years after surgery. Of all patients, 88.6% showed significant clinical improvement.

CONCLUSIONS

Although there were complications and failures, syringopleural shunting produced satisfactory results at long-term follow-up.

Positive and negative predictors for good outcome after decompressive surgery for Chiari malformation type 1 as scored on the Chicago Chiari Outcome Scale

OBJECTIVE

Posterior fossa decompression (PFD) is commonly applied as treatment for Chiari malformation type 1 (CM1), an entity which is associated with a variety of presenting symptoms but little data correlating symptoms to surgical outcome. We applied the Chicago Chiari Outcome Scale (CCOS), a novel 16-point tool for evaluating outcome, to a consecutive series of CM1 patients to identify specific factors or symptoms that predispose to a better or worse surgical outcome.

METHODS

A series of 167 CM1 patients who underwent initial PFD at our institution (consisting of suboccipital craniectomy, C1 laminectomy, subarachnoid exploration, and expansile autologous pericranial duraplasty) were reviewed. Pre-operative signs, symptoms, and characteristics were recorded, and odds ratios were calculated to identify significant pre-operative factors corresponding to a better or worse outcome on the CCOS.

RESULTS

Sensory deficits and peripheral neuropathy correlated with a lower score on the CCOS. Younger age at the time of surgery and, strikingly, presence of syringomyelia both correlated with a higher CCOS score.

DISCUSSION

Our results identify specific presenting factors that correlated with a better or worse outcome after CM1 decompression. These data also demonstrate that CCOS scoring allows for a rigorous comparison of outcome in different patient populations and between variable operative techniques. Application of CCOS scoring to a larger patient population undergoing a variety of operative CM1 treatments should allow for better-informed decisions regarding patient selection and treatment options for CM1.

Subcutaneous blood patch for iatrogenic suboccipital pseudomeningocele following decompressive suboccipital craniectomy and enlarging duroplasty for the treatment of Chiari I malformation. Technical note

PURPOSE

Epidural blood patch (EBP) represents one of the best nonsurgical treatment for intracranial hypotension syndrome. Orthostatic headache caused by reduced intracranial cerebrospinal fluid (CSF) pressure, like in "spontaneous" intracranial hypotension or as consequence of lumbar puncture or anesthesiological procedure, can be managed with the injection of autologous blood on the epidural space with a successful rate of 89%, increased to 97% after a second application.

MATERIALS AND METHODS

This 9-year-old girl was admitted to our department because of a suboccipital pseudomeningocele. She was previously operated on for a Chiari type I malformation by suboccipital craniectomy, C1 laminectomy and duraplasty. At the admission, she complained for nucal pain. Brain MRI showed a large suboccipital fluid collection that persisted even after the revision of the duraplasty and the placement of an external lumbar drainage. The child underwent a first injection of a mixture of blood (10 ml) and fibrin glue (10 ml) within the subcutaneous space after needle-aspiration of the collection. The same treatment was repeated 3 weeks later.

RESULTS

The procedures were well tolerated and no local or systemic complications occurred. The fluid collection was significantly reduced after the first injection and it was completely effaced following the second one. Such a result remained stable after 3 months, as demonstrated by MRI. No recurrence of the pseudomeningocele was detected at the last clinical control (8-month follow-up).

CONCLUSION

Subcutaneous blood patch could represent a safe and effective option for the treatment of CSF fistula, especially in case of failure of the traditional management.

Ventral compression in adult patients with Chiari 1 malformation sans basilar invagination: cause and management

BACKGROUND

A small subset of patients with adult Chiari I malformation without basilar invagination (BI) and instability show ventral cervicomedullary distortion/compression and have symptoms pertaining to that. The cause of this ventral compression remains speculative. Additionally, it is unclear if these patients would require ventral decompression with posterior fusion or only posterior decompression would suffice.

METHODS

Sixteen adult patients with Chiari I malformation with significant ventral cervicomedullary compression, in the absence of BI, were included in the study. Atlantoaxial dislocation (AAD) was excluded in these patients by flexion-extension craniovertebral junction X-rays and computed tomography (CT). Their clinical profile, especially symptoms pertaining to cervicomedullary compression, i.e. dysphagia, dysarthria and spasticity, were graded. The ventral cervicomedullary compression (VCMC) was quantified using pBC2 (maximum perpendicular distance to the basion-infero posterior point of the C2 body) on sagittal magnetic resonance imaging (MRI) and only those patients with pBC2 ≥9 mm were included. Furthermore, retroversion of dens and retro odonotid tissue thickness was calculated in each patient. Fifteen patients underwent posterior decompression alone and one refused surgery. Follow-up was done every 3 months. Repeat MRI was done at 1 year following surgery to look for pBC2.

RESULTS

The mean pBC2 was 11 ± 0.2 mm. Retroversion of dens was responsible for VCMC in three patients and periodontoid crown in 13. There was no correlation between the tonsillar descent, age and the pBC2. All patients improved in symptoms of cervicomedullary compression following surgery. One patient worsened 6 months after initial improvement. The pBC2 did not change, as seen on follow-up MRI done in five patients.

CONCLUSIONS

VCMC in adult patients with Chiari I malformation in the absence of BI and/or AAD is due to periodontoid tissue (crown) or retroverted dens. Though a long-term study is required, it appears that all patients with Chiari I malformation, irrespective of the VCMC, can be given a chance with posterior decompression alone. Transoral decompression with posterior fusion may be required in a small subset of patients who fail to improve or worsen following posterior decompression only.

Identifying myelopathy caused by thoracic syringomyelia: a case report

Myelopathy is a form of neurological disease caused by compression of the spinal cord. Upper and lower quarter screens are commonly used in identifying myelopathy, although most of the screen components demonstrate poor or unstudied diagnostic value. The purpose of this case report is to describe the diagnostic process in detecting syringomyelia, an intramedullary lesion that may cause myelopathy. The patient was a 47-year-old female with a thoracic syrinx that was discovered by spinal magnetic resonance imaging (MRI) following a complicated and delayed clinical diagnostic course. Following surgical intervention and a two-week inpatient rehabilitation stay, the patient was discharged using a rolling walker for ambulation and was performing most transfers with modified independence. A complicating pattern of signs and symptoms combined with a diagnostic process guided by poorly studied screen components demonstrates the diagnostic dilemma associated with identifying the cause of myelopathy within the thoracic spine. This also indicates the need for further investigation of individual and clustered components of the neurological screen to improve the ability to identify patients in need of complete imaging studies in a more timely fashion.

Classification of symptomatic Chiari I malformation to guide surgical strategy

BACKGROUND

Treatment options for Chiari I malformations include posterior fossa decompression (PFD) with additional techniques including laminectomy, intradural exploration, and duraplasty. Neuroimaging findings of cisterna magna volume, syringomyelia, and intraoperative ultrasonography may tailor surgical intervention.

METHODS

We developed an algorithm classifying symptomatic Chiari I patients into three groups to define minimum operation. Without syringomyelia, the presence of cisterna magna defined Group A and the absence defined Group B. Patients with syrinx formed Group C. Mild structural pathology (Group A) or adequate space following PFD (Group B, normal intraoperative ultrasound (IOUS)) should be treated by PFD alone. Conversely, presence of syringomyelia (Group C) or inadequate space following PFD (Group B, abnormal IOUS) should additionally have duraplasty. We applied this algorithm to patients treated at a single institution over 16 years.

RESULTS

Twenty-four symptomatic Chiari I malformation patients were divided into three groups that did not differ by age, gender, or extent of tonsillar ectopia. All patients treated by this algorithm experienced clinical and radiographic improvement. This included eight Group B patients who underwent PFD only (n=6) or additional duraplasty (n=2) decided by IOUS.

CONCLUSION

Treatment of symptomatic Chiari I malformation may have inadequate outcome with conservative strategy or complications with aggressive strategy. This algorithm utilizes preoperative neuroimaging and intraoperative ultrasound to tailor intervention, with excellent clinical outcome and radiographic syrinx resolution on application to 24 patients. Further validation requires prospective multicenter evaluation with larger patient population.

Deformative stress associated with an abnormal clivo-axial angle: A finite element analysis

Background:

Chiari malformation, functional cranial settling and subtle forms of basilar invagination result in biomechanical neuraxial stress, manifested by bulbar symptoms, myelopathy and headache or neck pain. Finite element analysis is a means of predicting stress due to load, deformity and strain. The authors postulate linkage between finite element analysis (FEA)-predicted biomechanical neuraxial stress and metrics of neurological function.

Methods:

A prospective, Internal Review Board (IRB)-approved study examined a cohort of 5 children with Chiari I malformation or basilar invagination. Standardized outcome metrics were used. Patients underwent suboccipital decompression where indicated, open reduction of the abnormal clivo-axial angle or basilar invagination to correct ventral brainstem deformity, and stabilization/ fusion. FEA predictions of neuraxial preoperative and postoperative stress were correlated with clinical metrics.

Results:

Mean follow-up was 32 months (range, 7-64). There were no operative complications. Paired t tests/ Wilcoxon signed-rank tests comparing preoperative and postoperative status were statistically significant for pain, bulbar symptoms, quality of life, function but not sensorimotor status. Clinical improvement paralleled reduction in predicted biomechanical neuraxial stress within the corticospinal tract, dorsal columns and nucleus solitarius.

Conclusion:

The results are concurrent with others, that normalization of the clivo-axial angle, fusion-stabilization is associated with clinical improvement. FEA computations are consistent with the notion that reduction of deformative stress results in clinical improvement. This pilot study supports further investigation in the relationship between biomechanical stress and central nervous system (CNS) function.

Chiari type I malformation, syncope, headache, hypoglycemia and hepatic steatosis in an 8-year old girl: a causal association?

Chiari type I malformation (CMI) is a congenital hindbrain anomaly characterized by downward displacement of the cerebellar tonsils through the foramen magnum. Chiari type I malformation often presents with a complex clinical picture and can be sporadic or linked to a variety of genetic conditions. We report on a girl in whom Chiari type I malformation was associated with hypoglycemia, headache, vertigo, syncope and hepatic steatosis. We hypothesize that these symptoms are primarily a consequence of Chiari type I malformation.