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Normalization of hindbrain morphology after decompression of Chiari malformation Type I.

ABSTRACT: OBJECT:Chiari malformation Type I (CM-I) is characterized by hindbrain deformity. We investigated the effects of craniocervical decompression surgery on the anatomical features of hindbrain deformity with a prospective MRI study of patients with CM-I. METHODS:A prospective longitudinal study was conducted in 48 patients with CM-I (39 with syringomyelia) treated with craniocervical decompression. Clinical examinations and cervical MRI were performed before surgery and 1 week, 3-6 months, and annually after surgery. Hindbrain deformity was defined by tonsillar ectopia, pointed cerebellar tonsils, and/or cervicomedullary protuberance. The length of the clivus, basiocciput (sphenooccipital synchondrosis to basion), supraocciput (internal occipital protuberance to opisthion), and anteroposterior (AP) width of CSF pathways at the foramen magnum were measured and compared with those from 18 healthy volunteers (control group). RESULTS:Before surgery, the patients' posterior fossa bones were short and their CSF pathways were narrow. All patients had tonsillar ectopia (mean [± SD] 12.3 ± 5.1 mm; normal 0.3 ± 1.0). The majority of patients had pointed tonsils and more than two-thirds exhibited a cervicomedullary protuberance. Clivus and basiocciput lengths were significantly shorter than the values obtained in the control group. However, the supraocciput length did not differ significantly from control measurements. The mean bulbopontine sulcus distance superior to the basion was 9.5 ± 2.6 mm (vs 13.6 ± 2.8 mm in controls; p < 0.0001). The AP widths of the CSF pathways at the level of the foramen magnum were significantly narrowed. After surgery, CSF pathways significantly expanded both ventrally and dorsally. By 3-6 months after surgery, pointed tonsils became round, cervicomedullary protuberance disappeared, and tonsillar ectopia diminished by 51% (to 6.0 ± 3.3 mm; p < 0.0001). CONCLUSIONS:The cerebellar tonsils and brainstem assumed a normal appearance within 6 months after craniocervical decompression. These findings support the concept that the CM-I is not a congenital malformation of the neural elements but rather an acquired malformation that arises from pulsatile impaction of the cerebellar tonsils into the foramen magnum. Clinical trial registration no.: NCT00001327.

SUBMITTER: Heiss JD

PROVIDER: S-EPMC3786329 | biostudies-literature | 2012 Nov

REPOSITORIES: biostudies-literature

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Normalization of hindbrain morphology after decompression of Chiari malformation Type I.

Heiss John D JD Suffredini Giancarlo G Bakhtian Kamran D KD Sarntinoranont Malisa M Oldfield Edward H EH

Journal of neurosurgery 20120914 5

<h4>Object</h4>Chiari malformation Type I (CM-I) is characterized by hindbrain deformity. We investigated the effects of craniocervical decompression surgery on the anatomical features of hindbrain deformity with a prospective MRI study of patients with CM-I.<h4>Methods</h4>A prospective longitudinal study was conducted in 48 patients with CM-I (39 with syringomyelia) treated with craniocervical decompression. Clinical examinations and cervical MRI were performed before surgery and 1 week, 3-6 m ...[more]

PMID: 22978540

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Project description:BackgroundTreatment of Chiari malformation can include suboccipital decompression with resection of one cerebellar tonsil. Its effects on ocular motor and cerebellar function have not yet been systematically examined.ObjectiveTo investigate whether decompression, including resection of one cerebellar tonsil, leads to ocular motor, vestibular, or cerebellar deficits.Patients and methodsTen patients with Chiari malformation type 1 were systematically examined before and after (1 week and 3 months) suboccipital decompression with unilateral tonsillectomy. The work-up included a neurological and neuro-ophthalmological examination, vestibular function, posturography, and subjective scales. Cerebellar function was evaluated by ataxia rating scales.ResultsDecompression led to a major subjective improvement 3 months after surgery, especially regarding headache (5/5 patients), hyp-/dysesthesia (5/5 patients), ataxia of the upper limbs (4/5 patients), and paresis of the triceps and interosseal muscles (2/2 patients). Ocular motor disturbances before decompression were detected in 50% of the patients. These symptoms improved after surgery, but five patients had new persisting mild ocular motor deficits 3 months after decompression with unilateral tonsillectomy (i.e., smooth pursuit deficits, horizontally gaze-evoked nystagmus, rebound, and downbeat nystagmus) without any subjective complaints. Impaired vestibular (horizontal canal, saccular, and utricular) function improved in five of seven patients with impaired function before surgery. Posturographic measurements after surgery did not change significantly.ConclusionDecompression, including resection of one cerebellar tonsil, leads to an effective relief of patients' preoperative complaints. It is a safe procedure when performed with the help of intraoperative electrophysiological monitoring, although mild ocular motor dysfunctions were seen in half of the patients, which were fortunately asymptomatic.

Project description:  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.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.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.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.

Project description:ObjectiveOptimal management of pediatric Chiari malformation type I (CM-I) is much debated, chiefly due to the lack of validated tools for outcome assessment, with very few tools incorporating patient-centered measures of health-related quality of life (HRQOL). Although posterior fossa decompression (PFD) benefits a subset of patients, prediction of its impact across patients is challenging. The primary aim of this study was to investigate the role of patient-centered HRQOL measures in the assessment and prediction of outcomes after PFD.MethodsThe authors collected HRQOL data from a cohort of 20 pediatric CM-I patients before and after PFD. The surveys included assessments of selected Patient-Reported Outcomes Measurement Information System (PROMIS) health domains and were used to generate the PROMIS preference (PROPr) score, which is a measure of HRQOL. PROMIS is a reliable standardized measure of HRQOL domains such as pain, fatigue, depression, and physical function, which are all relevant to CM-I. The authors then compared the PROPr scores with Chicago Chiari Outcome Scale (CCOS) scores derived from time-matched clinical documentation. Finally, the authors used the PROPr scores as an outcome measure to predict postsurgical HRQOL improvement at 1 year on the basis of patient demographic characteristics, comorbidities, and radiological and physical findings. The Wilcoxon signed-rank test, Mann-Whitney U-test, and Kendall's correlation were used for statistical analysis.ResultsAggregate analysis revealed improvement of pain severity after PFD (p = 0.007) in anatomical patterns characteristic of CM-I. Most PROMIS domain scores trended toward improvement after surgery, with anxiety and pain interference reaching statistical significance (p < 0.002 and p < 0.03, respectively). PROPr scores also significantly improved after PFD (p < 0.008). Of the baseline patient characteristics, preexisting scoliosis was the most accurate negative predictor of HRQOL improvement after PFD (median -0.095 vs 0.106, p < 0.001). A correlation with modest magnitude (Kendall's tau range 0.19-0.47) was detected between the patient-centered measures and CCOS score.ConclusionsThe authors observed moderate improvement of HRQOL, when measured using a modified panel of PROMIS question banks, in this pilot cohort of pediatric CM-I patients after PFD. Further investigations are necessary to validate this tool for children with CM-I and to determine whether these scores correlate with clinical and radiographic findings.

Project description:IntroductionWe hypothesize that surgical decompression for Chiari malformation type 1 (CM-1) is associated with statistically significant decrease in tonsillar pulsatility and that the degree of pulsatility can be reliably assessed regardless of the experience level of the reader.MethodsAn Institutional Review Board (IRB)-approved Health Insurance Portability and Accountability Act (HIPAA)-compliant retrospective study was performed on 22 children with CM-1 (8 males; mean age 11.4 years) who had cardiac-gated true-FISP sequence and phase-contrast cerebrospinal fluid (CSF) flow imaging as parts of routine magnetic resonance (MR) imaging before and after surgical decompression. The surgical technique (decompression with or without duraplasty) was recorded for each patient. Three independent radiologists with different experience levels assessed tonsillar pulsatility qualitatively and quantitatively and assessed peritonsillar CSF flow qualitatively. Results were analyzed. To evaluate reliability, Fleiss kappa for multiple raters on categorical variables and intra-class correlation for agreement in pulsatility ratings were calculated.ResultsAfter surgical decompression, the degree of tonsillar pulsatility appreciably decreased, confirmed by t test, both qualitatively (p values <0.001, <0.001, and 0.045 for three readers) and quantitatively (amount of decrease/p value for three readers 0.7 mm/<0.001, 0.7 mm/<0.001, and 0.5 mm/0.022). There was a better agreement among the readers in quantitative assessment of tonsillar pulsatility (kappa 0.753-0.834), compared to qualitative assessment of pulsatility (kappa 0.472-0.496) and qualitative assessment of flow (kappa 0.056 to 0.203). Posterior fossa decompression with duraplasty led to a larger decrease in tonsillar pulsatility, compared to posterior fossa decompression alone.ConclusionTonsillar pulsatility in CM-1 is significantly reduced after surgical decompression. Quantitative assessment of tonsillar pulsatility was more reliable across readers than qualitative assessments of tonsillar pulsatility or CSF flow.

Project description:ObjectiveThe aim of this study was to determine the association of postoperative dexmedetomidine with markers of pain in children undergoing Chiari malformation decompression. The authors hypothesized that patients receiving dexmedetomidine postoperatively would have decreased cumulative opiate use. They further hypothesized that there would be no difference in median pain scores, outcomes, or medication adverse events.MethodsAn IRB-approved retrospective cohort study of patients undergoing Chiari malformation decompression from December 1, 2015, to December 31, 2018, was performed. Patients aged 0-21 years who underwent intradural Chiari malformation decompression at a single institution were included. Data for those who used dexmedetomidine postoperatively were compared with those who did not use dexmedetomidine. The primary outcome was cumulative opiate use throughout hospitalization. Secondary outcomes included pain scores, ancillary medication use, adverse events, hospital and ICU length of stay, readmission rates, and hospital cost.ResultsThe authors reviewed the records of 172 patients who underwent Chiari malformation decompression. Of those patients, 86 received dexmedetomidine postoperatively and 86 did not. Demographics were not different between the groups. Patients who received dexmedetomidine postoperatively received more doses of dexamethasone and were also more frequently exposed to dexmedetomidine intraoperatively (p = 0.028). Patients who received dexmedetomidine postoperatively used fewer morphine equivalents during their admission (1.02 mg/kg vs 1.43 mg/kg, p = 0.003). The patients who received dexmedetomidine postoperatively also had lower median pain scores on postoperative day 0 (0 vs 2, p < 0.001), lower median pain scores throughout the entire admission (1 vs 2, p < 0.001), and lower maximum pain scores recorded (6 vs 8, p = 0.005). Adjusting for steroid dose number and intraoperative dexmedetomidine exposure, postoperative dexmedetomidine remained associated with lower opiate dosing, lower pain scores on postoperative day 0, lower scores throughout hospital stay, and lower maximum pain scores. Patients who received dexmedetomidine had shorter hospital lengths of stay by 19 hours (p < 0.001). There were no statistically significant differences in medication adverse events or hospital costs between the two groups.ConclusionsPostoperative dexmedetomidine use was associated with decreased opiate use, lower pain scores, and shorter hospital length of stay in this cohort. Dexmedetomidine may be considered as a safe adjuvant medication that may have opiate-sparing effects for this patient population.

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Normalization of hindbrain morphology after decompression of Chiari malformation Type I.

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Normalization of hindbrain morphology after decompression of Chiari malformation Type I.

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