Surgical treatment of Chiari I malformation: indications and approaches

Vocal Cord Paralysis in Pediatric Chiari Malformation: A Systematic Review and Meta-analysis

OBJECTIVE

Arnold-Chiari Malformation is one possible cause of congenital vocal cord paralysis (VCP). The natural history of VCP in children with Chiari malformation has previously been limited to small case studies. This systematic review seeks to better characterize the prognostic factors that may predict symptom severity and resolution of congenital VCP in children with Arnold-Chiari malformation. We hypothesized that the onset of stridor or VCP at a younger age would be associated with a poorer prognosis and earlier intervention with posterior fossa decompression would be associated with better outcomes.

DATA SOURCES

PubMed, Web of Science, Cochrane Library, and bibliographic review.

REVIEW METHODS

A systematic review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Database search yielded 866 articles. Study abstracts were reviewed by 2 independent examiners. One hundred and seventy-six studies underwent full-text review. The following were extracted: age at onset of stridor or VCP, Chiari malformation type, laryngoscopy findings, type and timing of neurosurgical intervention, and tracheostomy history. Statistical analyses utilized χ2 tests.

RESULTS

Younger age at symptom onset showed statistically significant associations with decreased likelihood for symptom resolution and tracheostomy decannulation. The shorter time interval from symptom onset to neurosurgical intervention was not significantly associated with better outcomes.

CONCLUSION

This meta-analysis suggests poorer prognosis in those with earlier-onset symptoms, reinforcing prior case series findings. Additional prospective studies are needed to elucidate the natural history and utility of early intervention in children with vocal cord paralysis secondary to Chiari malformation.

Morphological and ultrastructural investigation of the posterior atlanto-occipital membrane: Comparing children with Chiari malformation type I and controls

INTRODUCTION

The fibrous posterior atlanto-occipital membrane (PAOM) at the craniocervical junction is typically removed during decompression surgery for Chiari malformation type I (CM-I); however, its importance and ultrastructural architecture have not been investigated in children. We hypothesized that there are structural differences in the PAOM of patients with CM-I and those without.

METHODS

In this prospective study, blinded pathological analysis was performed on PAOM specimens from children who had surgery for CM-I and children who had surgery for posterior fossa tumors (controls). Clinical and radiographic data were collected. Statistical analysis included comparisons between the CM-I and control cohorts and correlations with imaging measures.

RESULTS

A total of 35 children (mean age at surgery 10.7 years; 94.3% white) with viable specimens for evaluation were enrolled: 24 with CM-I and 11 controls. There were no statistical demographic differences between the two cohorts. Four children had a family history of CM-I and five had a syndromic condition. The cohorts had similar measurements of tonsillar descent, syringomyelia, basion to C2, and condylar-to-C2 vertical axis (all p>0.05). The clival-axial angle was lower in patients with CM-I (138.1 vs. 149.3 degrees, p = 0.016). Morphologically, the PAOM demonstrated statistically higher proportions of disorganized architecture in patients with CM-I (75.0% vs. 36.4%, p = 0.012). There were no differences in PAOM fat, elastin, or collagen percentages overall and no differences in imaging or ultrastructural findings between male and female patients. Posterior fossa volume was lower in children with CM-I (163,234 mm3 vs. 218,305 mm3, p<0.001), a difference that persisted after normalizing for patient height (129.9 vs. 160.9, p = 0.028).

CONCLUSIONS

In patients with CM-I, the PAOM demonstrates disorganized architecture compared with that of control patients. This likely represents an anatomic adaptation in the presence of CM-I rather than a pathologic contribution.

Decoding Chiari Malformation and Syringomyelia: From Epidemiology and Genetics to Advanced Diagnosis and Management Strategies

Chiari Malformation and Syringomyelia are neurosurgical entities that have been the subject of extensive research and clinical interest. Globally prevalent, these disorders vary demographically and have witnessed evolving temporal trends. Chiari Malformation impacts the normal cerebrospinal fluid flow, consequently affecting overall health. Key observations from canine studies offer pivotal insights into the pathogenesis of Syringomyelia and its extrapolation to human manifestations. Genetics plays a pivotal role; contemporary knowledge identifies specific genes, illuminating avenues for future exploration. Clinically, these disorders present distinct phenotypes. Diagnostically, while traditional methods have stood the test of time, innovative neurophysiological techniques are revolutionizing early detection and management. Neuroradiology, a cornerstone in diagnosis, follows defined criteria. Advanced imaging techniques are amplifying diagnostic precision. In therapeutic realms, surgery remains primary. For Chiari 1 Malformation, surgical outcomes vary based on the presence of Syringomyelia. Isolated Syringomyelia demands a unique surgical approach, the effectiveness of which is continually being optimized. Post-operative long-term prognosis and quality of life measures are crucial in assessing intervention success. In conclusion, this review amalgamates existing knowledge, paving the way for future research and enhanced clinical strategies in the management of Chiari Malformation and Syringomyelia.

The Pathogenesis of Chiari Malformation and Syringomyelia: A Case Report and Systematic Review of Current Theories

We report a case of a 42-year-old female presenting with left axillary pain radiating down the arm and weakness in the ipsilateral hand. Specialist examinations of neurological and musculoskeletal systems were insignificant. Magnetic resonance imaging (MRI) of the whole spine and brain revealed cerebellar tonsillar herniation of 9-10mm indicating a Chiari type 1 malformation and a large tubular T2 high-intensity lesion in the cervical cord, extending from the C2/3-disc level down to C6/C7 as well as a similar but smaller lesion behind the bodies of C7 and T1. Both lesions were consistent with syringomyelia. Surgical intervention was deemed inappropriate, and she was treated with three months of physiotherapy. Regular follow-up for two years showed gradual symptom resolution, syrinx shrinkage, and no further complications arising secondary to Chiari type 1 malformation. Chiari malformation is an anatomical anomaly of the cranio-cervical junction. It is often incidentally found on MRI, but although asymptomatic in the population, complications associated with the condition such as syringomyelia are a common initial presentation. The relationship between Chiari malformation, particularly Chiari type 1 malformation, and syringomyelia is close with the majority of patients often presenting with idiopathic syringomyelia also found to have a Chiari type 1 malformation. Considerable discussion about the pathogenic mechanisms for syringomyelia development in Chiari malformation is recognized and advancing continually.

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.

Headache and Other Symptoms in Chiari Malformation Type I Are Associated with Cerebrospinal Fluid Flow Improvement After Decompression: A Two-Institutional Study

OBJECTIVE

Chiari malformation type I (CMI) is a common neurologic condition and surgery is the standard treatment. We aim to establish the cerebrospinal fluid (CSF) flow change as a potential objective indicator of surgical efficacy to improve symptoms.

METHODS

We performed a retrospective 2-center analysis of surgically treated patients with CMI. Qualitative CSF flow studies obtained preoperatively and postoperatively were analyzed by the neuroradiologist, seeking improvement in CSF flow. Symptom status, including headache and neck pain, were recorded.

RESULTS

Forty-nine patients were identified between 2010 and 2017. The average age was 36 years, with 47 females. After decompression, CSF flow was improved in 41 patients (group A) and unchanged in 8 (group B). Group A and B had a mean age of 34 and 42 years (P < 0.05) and an average tonsillar herniation of 8.3 and 8.5 mm (P = 0.40), respectively. Group A had improved clinical outcomes, compared with group B (P = 0.024), more specifically, in headache (50% vs. 37%), neck pain (66% vs. 33%), dizziness (78% vs. 50%), vision symptoms (84% vs. 80%), and weakness (100% vs. 66%), respectively. Group B had the only patient who did worse on clinical follow-up.

CONCLUSIONS

Patients with CMI often present with a constellation of symptoms. We showed a significant association between improved CSF flow after decompression and symptom alleviation. Further, our study suggests that the presence of improved CSF flow postoperatively could represent an objective indicator for improved patient outcomes.

The factors affecting the outcomes of conservative and surgical treatment of chiari i adult patients: a comparative retrospective study

BACKGROUND

The prognosis of the Chiari malformation type 1 (CM1) demonstrates a variant spectrum that varies from full recovery to complicated worse neurological disability.

OBJECTIVE

To investigate the factors affecting the outcomes of conservative and surgical treatment for CM1 by evaluating adult patients consecutively managed at our institutions.

MATERIALS AND METHODS

We retrospectively reviewed the medical records of patients diagnosed with CM1 at two reference neurosurgical centers for eight years (2010-2017). We selected all CM1 adult patients who managed conservatively or surgically as the core sample for this study. For clinical evaluation, we used a Chicago Chiari Outcome Scale (CCOS). For radiological assessment, we adopted both craniocervical and contrast-phase MRIs. We investigate factors such as age, sex, pretreatment symptoms, symptoms duration, and radiological findings in both groups.

RESULTS

Ninety patients were treated conservatively. After a progression, five of them were treated surgically later and included in a total of 72 patients who underwent decompressive surgery. We successfully managed 85 patients (94.4%) of the conservative group and 64 patients (88.9%) of the surgical group. We found that patients with aqueductal stroke volume (ASV) of 12 µl are surgical candidates. We observed a strong positive correlation between clinical improvement and the increase in ASV values.

CONCLUSIONS

ASV≤12 µl is a significant predictor for surgical intervention. The presence of heavy sleep apnea or/and functional symptoms, tonsillar herniation >13.4 mm on coronal images, low ASV, long symptom durations, and a syrinx are the independent prognostic factors that affected outcomes negatively.

Inpatient outcomes of posterior fossa decompression with or without duraplasty for Chiari malformation type I

OBJECTIVE

Chiari malformation type 1 (CM-1) is a congenital neurologic condition in which the cerebellar tonsils herniate below the foramen magnum, resulting in symptoms such as headache and neck pain. Two common surgical treatment approaches are posterior fossa decompression with (PFDD) and without duraplasty (PFD). Previous single-center studies have demonstrated increased neurologic complications after PFDD compared to PFD. The goal of this study is to determine differences in inpatient complications and hospitalization data among patients treated with these surgical techniques using a nationwide sample.

METHODS

The National Inpatient Sample (NIS) was queried for years 2012-2015 for all patients with a primary diagnosis of CM-1 who underwent PFD or PFDD. Differences in baseline demographics and comorbidities were accounted for in subsequent analysis using propensity score matching. Hospitalization measures and inpatient complications of the two cohorts were compared using Chi-squared tests and t-tests when appropriate.

RESULTS

A total of 2395 patients with CM-1 were included in this study, with 750 (31.3%) undergoing PFD and 1645 (68.7%) undergoing PFDD. PFDD was associated with higher total hospital costs than PFD. There were no significant differences in other hospitalization or discharge data, non-neurologic complications, or CNS complications (CSF leak, pseudomeningocele, abscess, meningitis, stroke) between the two surgical groups.

CONCLUSIONS

This study represents the largest national analysis to date of adult CM-1 patients undergoing PFD or PFDD. Our findings suggest that whether the decision is made to perform the less invasive PFD or more invasive PFDD, inpatient complications and hospitalization data will not significantly differ.

Nonoperative management of enlarging syringomyelia in clinically stable patients after decompression of Chiari malformation type I

OBJECTIVE

The authors aimed to describe the natural history and optimal management of persistent syringomyelia after suboccipital craniectomy for Chiari malformation type I (CM-I).

METHODS

A cohort of all patients who presented to a tertiary pediatric hospital with newly diagnosed CM-I between 2009 and 2017 was identified. Patients with persistent or worsened syringomyelia were identified on the basis of a retrospective review of medical records and imaging studies. The management of these patients and their clinical courses were then described.

RESULTS

A total of 153 children with CM-I and syringomyelia were evaluated between 2009 and 2017. Of these, 115 (68.8%) patients underwent surgical intervention: 40 patients underwent posterior fossa decompression (PFD) alone, 43 underwent PFD with duraplasty, and 32 underwent PFD with duraplasty and fourth ventricle stent placement. Eleven (7.19%) patients had increased syringomyelia on subsequent postoperative imaging. Three of these patients underwent revision surgery because of worsening scoliosis or pain, 2 of whom were lost to follow-up, and 4 were managed nonoperatively with close surveillance and serial MRI evaluations. The syringes decreased in size in 3 patients and resolved completely in 1 patient.

CONCLUSIONS

Persistent or worsened syringomyelia after CM-I decompression is uncommon. In the absence of symptoms, nonoperative management with close observation is safe for patients with persistent syrinx.

Comparison of two surgical techniques in Chiari Malformation Type 1 Patients: Duraplasty alone vs duraplasty with arachnoid dissection

OBJECT

Optimal surgical technique to restore the cerebrospinal fluid flow through the foramen magnum remains to be debated in Chiari malformation type 1 (CM-1) patients.

METHOD

This study included 46 patients with CM-1 who underwent surgical treatment by one of two methods: posterior fossa bone decompression (BD) with arachnoid preserving duraplasty (Group 1) and BD with duraplasty and arachnoid dissection (Group 2). Complaints of the patient population and neurological findings were assessed with Neck Disability Index (NDI) and Europe Quality of Life 5 Dimensions (EQ-5D) in pre- and postoperative periods.

RESULTS

NDI and EQ-5D scores improved in overall patient population and in each individual surgical group. Both groups showed a significant decrease in size of syringomyelia cavity. Complications resulting in recurrent treatments and re-operations occurred in 15% of patients (n = 7); six of them were from Group 2.

CONCLUSION

CM-1 patients benefit significantly from surgical treatment. Duraplasty should be included to surgical technique. Avoiding arachnoid dissection may lead to better results regarding complication rates.

A titanium implant for Chiari malformation Type 1 surgery

Background

Concepts of Chiari malformation Type 1 (CM1) surgery in the present time significantly different. The most common complications are pseudomeningocele (12%) and postoperative CSF leak (5%). The development of pseudomeningocele may be associated with inappropriate restoration of bone and muscles relations.

Methods

The pilot study involved 11 patients aged 24-64 years with a diagnosis of CM1 who had indications for surgical treatment. Special titanium implant enabling fixation of the occipital and cervical muscles at the projections of their normal attachments was developed, it was placed to occipital bone on the final stages of surgical intervention. Surgical technique promoted tightened wound closure neutralizing formation of "dead space" at the place of occipital craniectomy and between muscle layers. The implant was produced by direct metal laser sintering method for each patient individually.

Results

There were no complications during the hospitalization and follow-up period. Postoperative MRI demonstrated adequate formation of the cisterna magna and the absence of pseudomeningocele. During follow-up period there were no signs of pseudomeningocele, CSF leak, surgical scar complications, implant-associated infections, and other complications.

Conclusion

In the study group, no pseudomeningocele cases as long as any other complications associated with surgery had been revealed. The efficacy of the proposed surgical technique using the developed implant should be evaluated in clinical trials with larger patient samples. To simplify preoperative planning and manufacturing of the implant for each patient individually, a set of implants with different specified sizes was developed.

Posterior Fossa Decompression and superficial durotomy rather than complete durotomy and duraplasty in the management of Chiari 1

Objective: We aimed to evaluate the effectiveness and reliability of posterior fossa decompression (PFD) and superficial durotomy in patients who underwent surgery for Chiari malformation type 1 (CM1).Materials and Methods: Our study included 54 patients with the diagnosis of CM1 who had surgery between January 2012 and June 2019. The patients were divided into two groups according to the surgical technique applied. Group 1 included 10 patients who underwent classic PFD and duraplasty, and Group 2 included 44 patients who underwent PFD and superficial durotomy surgery. Pre- and postoperative clinical signs and symptoms of each patient were recorded. Simultaneously, morphometric measurements were compared from computed tomography (CT) and magnetic resonance (MRI) images taken pre- and postoperatively. The data of the two groups were compared.Results: Of the 54 patients, 18 were male, and the mean age was 37.51 ± 15.14. A statistically significant difference was found between the pre- and postoperative morphometric measurements of the subarachnoid distance, craniocervical angle, syringomyelia, and hydrocephalus at the cerebellum level in Group 2 patients who underwent PFD and superficial durotomy surgery (p < 0.05). When morphometric measurements and clinical signs and symptoms of both groups were compared, no significant difference was found (p > 0.05). There was a 92% improvement in clinical signs and symptoms postoperatively. The complications seen in Group 1 decreased to a minimum in Group 2.Conclusion: We believe that a minimally invasive surgical method is superior to avoid major complications. We also found PFD and superficial durotomy shorten the duration of the patient's hospital stayAbbreviations: C1: cervical vertebra 1C2: cervical vertebra 2CM: Chiari malformationCM1: Chiari malformation type 1CSF: cerebrospinal fluidCT: computed tomographyMRI: magnetic resonance imagingPFD: posterior fossa decompressionUSG: ultrasonography.

Clinical and radiological evaluation of treated Chiari I adult patients: retrospective study from two neurosurgical centers

Chiari malformation type I (CM1) is a common neurosurgical disorder. It often causes debilitation in the affected patients. CM1 is a herniation of the caudal cerebellum into the spinal canal. This study aimed to evaluate the clinical and radiological outcomes of posterior fossa decompression and duraplasty (PFDD) in treated CM1 patients. In retrospective design, we reviewed the medical records of diagnosed patients with CM1 at two neurosurgical centers spanning 8 years from 2010 to 2017. We selected all CM1 patients who underwent PFDD surgery (n = 72) as the core sample for this study. We used the Chicago Chiari Outcome Scale (CCOS) to evaluate clinical outcomes. Pre- and postoperatively, we assessed the syrinx/cord ratio, the syrinx length, and the improvement of aqueductal stroke volume (ASV) on CSF flow MRIs. The mean value of CCOS was 14.1 ± 2.1. On midsagittal MRIs, the mean regression in ectopia tonsils was 9.4 ± 1.9 mm (i.e., mean pre- and postoperative tonsil herniation was 13.1 ± 3.1 mm and 4.0 ± 1.6 mm, respectively; p < 0.001). On coronal MRIs, the mean regression in ectopia tonsils was 8.4 ± 1.5 mm (i.e., mean pre- and postoperative tonsil herniation was 13.9 ± 2.4 mm and 5.8 ± 1.0 mm, respectively; p < 0.001). A strong positive correlation was observed between clinical improvement and the increase in ASV values. CSF flow MRIs can help in the surgical decision and follow-up of CM1 patients. ASV ≤ 12 μl is a significant predictor for surgical intervention. Full clinical and radiological evaluation utilizing CSF flow MRI are essential. Most syrinx cavities have regressed following PFDD.

Management of Chiari I malformations: a paradigm in evolution

PURPOSE

Despite decades of experience and research, the etiology and management of Chiari I malformations (CM-I) continue to raise more questions than answers. Controversy abounds in every aspect of management, including the indications, timing, and type of surgery, as well as clinical and radiographic outcomes. This review aims to outline past experiences, consolidate current evidence, and recommend directions for the future management of the Chiari I malformation.

METHODS

A review of recent literature on the management of CM-I in pediatric patients is presented, along with our experience in managing 1073 patients who were diagnosed with CM-I over the past two decades (1998-2018) at Children's National Medical Center (CNMC) in Washington DC.

RESULTS

The general trend reveals an increase in the diagnosis of CM-I at younger ages with a significant proportion of these being incidental findings (0.5-3.6%) in asymptomatic patients as well as a rise in the number of patients undergoing Chiari posterior fossa decompression surgery (PFD). The type of surgical intervention varies widely. At our institution, 104 (37%) Chiari surgeries were bone-only PFD with/without outer leaf durectomy, whereas 177 (63%) were PFD with duraplasty. We did not find a significant difference in outcomes between the PFD and PFDD groups (p = 0.59). An analysis of failures revealed a significant difference between patients who underwent tonsillar coagulation versus those whose tonsils were not manipulated (p = 0.02).

CONCLUSION

While the optimal surgical intervention continues to remain elusive, there is a shift away from intradural techniques in favor of a simple, extradural approach (including dural delamination) in pediatric patients due to high rates of clinical and radiographic success, along with a lower complication rate. The efficacy, safety, and necessity of tonsillar manipulation continue to be heavily contested, as evidence increasingly supports the efficacy and safety of less tonsillar manipulation, including our own experience.

Response of Syrinx Associated with Chiari I Malformation to Posterior Fossa Decompression with or without Duraplasty and Correlation with Functional Outcome: A Prospective Study of 22 Patients

Background

The aim of the study is to correlate the surgical outcome with radiological changes in patients with Chiari I malformation (CMI) with syrinx. We also compared long-term functional and radiographic outcome in CM1 patients treated with posterior fossa decompression (PFD) with or without duroplasty.

Patients and Methods

From December 2013 to October 2015, 22 patients who underwent surgery with the diagnosis of CMI and syrinx were included in the study. Measurements were performed on preoperative and postoperative magnetic resonance (MR) scans using the same software. All patients underwent PFD with or without duroplasty. Clinical results were evaluated on the basis of the Chicago Chiari Outcome Scale (CCOS). We assessed the degree of resolution of syrinx and outcome of Chiari decompression with PFD versus PFD with duroplasty. Mean duration of follow-up was 12.4 ± 5.37 months (range: 6-24 months).

Results

Out of 19 patients in whom syrinx diameter decreased on postoperative MR imaging, 17 (89.5%) improved based on CCOS and 2 (10.5%) were unchanged while out of three patients in whom syrinx worsened, 2 (66.7%) improved and 1 (33.3%) was unchanged (P = 0.37). The cord diameter was found to have decreased in 12 patients and of these 11 (91.7%) improved. The cord diameter increased in 10 patients, but 8 (80%) improved (P = 0.57). The mean changes in syrinx, cord, and syrinx/cord ratio were studied in both groups with and without duroplasty, were not statistically significant. In this study, radiological parameters failed to predict functional outcome.

Conclusions

The outcome does not correlate with change in any of the syrinx-related factors. Surgical decompression with or without duroplasty does not have a statistically significant relationship in the degree of syrinx resolution. Surgical decompression without duroplasty provides the benefits of surgical decompression while avoiding the complications of intradural techniques.

Hydrocephalus after foramen magnum decompression for Chiari I malformation successfully treated with the aspiration of pseudomeningocele: a case report

Background

Pseudomeningocele or cerebrospinal fluid leakage is one of the most common complications of foramen magnum decompression with duraplasty for Chiari I malformation. Usually, cerebrospinal fluid leakage is treated with lumbar drainage and/or secondary suture. However, if hydrocephalus occurs, spinal drainage may cause brain herniation.

Case presentation

A 54-year-old Japanese woman presented to our hospital with a 10-month history of bilateral finger extension weakness and clumsiness. Magnetic resonance imaging showed displacement of her cerebellar tonsils below the foramen magnum level, with syringomyelia presenting from the C4 to T8 level. Suboccipital craniectomy and C1 laminectomy with duraplasty were performed under general anesthesia. At 1 month after discharge, she again presented to our hospital due to severe headache and nausea. Magnetic resonance imaging of her cervical spine showed pseudomeningocele compressing her cerebellum and spinal cord. Magnetic resonance imaging of her brain also showed ventriculomegaly. Pseudomeningocele aspiration was performed, with 25 ml of fluid removed under X-ray control. Immediately after aspiration her headache and nausea decreased, and she reported improvement in her symptoms with increasing bilateral finger extension strength and decreasing bilateral upper extremity numbness at her 1-year follow-up.

Conclusions

Although there is a considerable risk of meningitis with the aspiration procedure of pseudomeningocele, an aspiration procedure may be an easy and effective treatment option for postoperative hydrocephalus after suboccipital craniotomy with duraplasty in a patient treated for Chiari I malformation.

Appropriate surgical procedures for Chiari type 1 malformation and associated syrinx based on radiological characteristics of the craniovertebral junction

Several surgical procedures can be applied for syrinx associated with Chiari type 1 malformation; however, it remains controversial as to which approach is the most effective. Here, we evaluated the indications and limitations of foramen magnum decompression (FMD) with or without dural plasty. Forty patients with Chiari type 1 malformation were surgically treated and followed up for > 12 months. Thirty-two patients (80.0%) underwent FMD with removal of only the outer dura mater layer, while eight patients underwent FMD with dural plasty. We evaluated surgery-related complications and preoperative radiological findings affecting syrinx shrinkage rates. Post-surgery, the mean syrinx shrinkage rates were 0.32 ± 0.44 in the outer layer-removal group and 0.72 ± 0.27 in the dural plasty group (P = 0.012). Surgery-related complications were less frequent, but reoperation was more frequent, in the outer layer-removal group. The extent of tonsillar descent significantly affected syrinx shrinkage in FMD with outer layer removal (P = 0.042). The outcomes of both approaches in patients with tonsillar descent < 10.0 mm were similar. The dura mater in the posterior fossa was thin, necessitating dural plasty with FMD, while the spinal dura was sufficiently thick for removal of the outer layer in the Chiari patients. These histological differences corresponded with the inferior margin of the cerebellar tonsil. Recognizing the appropriate surgical indication for achieving good post-procedural outcomes is necessary for reducing complications and improving outcomes of FMD for Chiari type 1 malformations.

Chiari 1 Malformation Surgery: Comparing Non-violation of the Arachnoid versus Arachnoid Opening and Thermocoagulation of the Tonsils

OBJECTIVE

Evidence is lacking concerning the myriad surgical techniques for type 1 Chiari malformation. This study evaluated the impact of arachnoid violation with tonsil thermocoagulation during surgical craniovertebral junction decompression.

METHODS

The evaluation included aspects of the neurologic examination and parameters of cerebrospinal fluid flow on magnetic resonance imaging during preoperative and postoperative periods. All patients underwent craniovertebral junction decompression and opening of the dura mater. Patients were divided into 2 study groups. Patients in group 1 did not undergo arachnoid violation. Patients in group 2 underwent tonsil manipulation and systematic opening of the fourth ventricle outlet.

RESULTS

There were 16 patients enrolled in each group (total of 32 patients). Regarding clinical improvement, there were no significant differences between groups in the postoperative period. Group 2 had more adverse events (relative risk 2.45, 95% confidence interval 1.55-3.86). In terms of cerebrospinal fluid flow parameter analyses, patients in group 1 achieved better results (P < 0.05).

CONCLUSIONS

For treatment of symptomatic type 1 Chiari malformation, craniovertebral junction decompression with arachnoid preservation (i.e., without tonsillar manipulation) seems more suitable than the addition of arachnoid opening and thermocoagulation of the tonsils.

Relationship between Cough-Associated Changes in CSF Flow and Disease Severity in Chiari I Malformation: An Exploratory Study Using Real-Time MRI

BACKGROUND AND PURPOSE

Currently no quantitative objective test exists to determine disease severity in a patient with Chiari I malformation. Our aim was to correlate disease severity in symptomatic patients with Chiari I malformation with cough-associated changes in CSF flow as measured with real-time MR imaging.

MATERIALS AND METHODS

Thirteen symptomatic patients with Chiari I malformation (tonsillar herniation of ≥5 mm) were prospectively studied. A real-time, flow-sensitized pencil-beam MR imaging scan was used to measure CSF stroke volume during rest and immediately following coughing and relaxation periods (total scan time, 90 seconds). Multiple posterior fossa and craniocervical anatomic measurements were also obtained. Patients were classified into 2 groups by neurosurgeons blinded to MR imaging measurements: 1) nonspecific Chiari I malformation (5/13)-Chiari I malformation with nonspecific symptoms like non-cough-related or mild occasional cough-related headache, neck pain, dizziness, paresthesias, and/or trouble swallowing; 2) specific Chiari I malformation (8/13)-patients with Chiari I malformation with specific symptoms and/or objective findings like severe cough-related headache, myelopathy, syringomyelia, and muscle atrophy. The Spearman correlation was used to determine correlations between MR imaging measurements and disease severity, and both groups were also compared using a Mann-Whitney U test.

RESULTS

There was a significant negative correlation between the percentage change in CSF stroke volume (resting to postcoughing) and Chiari I malformation disease severity (R = 0.59; P = .03). Mann-Whitney comparisons showed the percentage change in CSF stroke volume (resting to postcoughing) to be significantly different between patient groups (P = .04). No other CSF flow measurement or anatomic measure was significantly different between the groups.

CONCLUSIONS

Our exploratory study suggests that assessment of CSF flow response to a coughing challenge has the potential to become a valuable objective noninvasive test for clinical assessment of disease severity in patients with Chiari I malformation.

Case Report of Worth Syndrome and Chiari I Malformation: Unusual Association and Surgical Treatment

BACKGROUND

Worth syndrome or autosomal dominant endosteal hyperostosis (ADEH) is an extremely rare genetic disease involving increased bone density. To the author's knowledge, this is the second case report of a family with neurologic involvement associated with this condition along with its surgical treatment. The most effective treatment for clinically significant neurologic symptoms in this scenario is currently unknown, and there is sparse experience on surgical treatment for this condition reported in the literature. Therefore we aim to make a contribution to the identification of a standard and consistently successful surgical management.

CASE DESCRIPTION

Two patients, mother (Patient 1) and daughter (Patient 2), were diagnosed with Worth syndrome. Both presented with the typical facial characteristics described for ADEH. Interestingly, Patient 1 presented the novel mutation in the LRP5 gene that is associated with different conditions involving increased bone density. Although neurologic symptoms are infrequent in ADEH, both referred chronic headache, nausea, and vomiting. Neuroimaging showed an increased cranial bone density and Chiari I malformation. The patients underwent a midline suboccipital craniectomy with excision of the posterior arch of C1 and duroplasty. However, due to a symptomatic recurrence 5 years after surgery, Patient 1 was reoperated on. We extended the craniectomy and also carried out a C2 laminectomy.

CONCLUSION

After surgical interventions, patients' neurologic symptoms were successfully resolved. This report shows that posterior fossa decompression including duroplasty may be a valid treatment option in case of neurologic involvement.

Resolution of Tachyarrhythmia Following Posterior Fossa Decompression Surgery for Chiari Malformation Type I

INTRODUCTION

Chiari malformation (CM) type I commonly presents with symptoms such as tussive headaches, paresthesias, and, in severe cases, corticobulbar dysfunction. However, patients may present with atypical symptoms lending to the complexity in this patient population. We present a case of a CM patient presenting with atypical cardiac symptoms and arrhythmias, all of which resolved after surgical decompression.

CASE DESCRIPTION

A 31-year-old female presented with atypical chest pain, palpitations, tachycardia, headaches, and dizziness for 2 years. Multiple antiarrhythmics and ultimately cardiac ablation procedure proved to be ineffective. Magnetic resonance imaging revealed CM, and the patient ultimately underwent surgical decompression with subsequent resolution of her symptoms.

CONCLUSION

The surgical management of CM patients presenting with atypical symptoms can be challenging and often lead to delays in intervention. To our knowledge this is the only reported case of a patient presenting with tachyarrhythmia and atypical chest pain with resolution after Chiari decompression. We believe the dramatic improvement documented in the present case should serve to advance Chiari decompression in CM patients presenting with refractory tachyarrhythmia in whom no other discernable cause has been elucidated. Further studies are needed to better correlate the findings and to hopefully establish a criteria for patients that will likely benefit from surgical decompression.

Chiari malformation: Has the dilemma ended?

Chiari malformation as a clinical entity has been described more than hundred years ago. The concepts regarding pathogenesis, clinical features and management options have not yet conclusively evolved. Considering that a variety of treatment methods are being adopted to treat Chiari malformation is suggestive of the fact that confusion still reigns supreme in the minds of treating clinicians. Over the years, the understanding of Chiari malformation has changed from a disease process to a natural protective phenomenon and the treatment from decompression to fixation.

Pediatric Craniovertebral Junction Surgery

The craniovertebral junction (CVJ) has attracted more attention in pediatric medicine in recent years due to the progress in surgical technologies allowing a direct approach to the CVJ in children. The CVJ is the site of numerous pathologies, most originating in bone anomalies resulting from abnormal CVJ development. Before discussing the surgical approaches to CVJ, three points should be borne in mind: first, that developmental anatomy demonstrates age-dependent mechanisms and the pathophysiology of pediatric CVJ anomalies; second, that CT-based dynamic simulations have improved our knowledge of functional anatomy, enabling us to locate CVJ lesions with greater certainty; and third, understanding the complex structure of the pediatric CVJ also clarifies the surgical anatomy. This review begins with a description of the embryonic developmental process of the CVJ, comprising ossification and resegmentation of the somite. From the clinical perspective, pediatric CVJ lesions can be divided into three categories: developmental bony anomalies with or without instability, stenotic CVJ lesions, and others. After discussing surgery and management based on this classification, the author describes surgical outcomes on his hands, and finally proceeds to address controversial issues specific for pediatric CVJ surgery. The lessons, which the author has gleaned from his experience in pediatric CVJ surgery, are also presented briefly in this review. Recent technological progress has facilitated pediatric surgery of the CVJ. However, it is important to recognize that we are still far from reliably and consistently obtaining satisfactory results. Further progress in this area awaits contributions of the coming generations of pediatric surgeons.

Chiari type I malformation with cervicothoracic syringomyelia subterfuge as flail arm syndrome

Chiari type I malformation with cervicothoracic syringomyelia although very common in clinical practice usually in children can progress slowly and mimic muscular dystrophies in adulthood. We present a rare adult case of Chiari type I malformation with cervicothoracic syringomyelia subterfuge as Flail arm syndrome. A 44-year-old man was diagnosed with congenital type I Chiari malformation with cervicothoracic syringomyelia about 21 years ago without surgery. His health status deteriorated over the years until 21 days prior to presentation when he had severe pain in the right knee. In his upper limbs, he had bilateral corresponding severe weakness of 0/5 proximal strength and 0/5 strength in his distal muscles. Magnetic resonance imaging (MRI) revealed an enlargement of the spinal cord from C1-C4 level with a mass that appeared hypo-dense on T1 and hyperdense on T2. Syringomyelia is a potentially serious neurologic condition that can mimic other neuromuscular disorders. Early detection and diagnosis with MRI is crucial to avoid irreversible neurological complications. We suggest that whether asymptomatic or symptomatic, decompressive surgery should be carried out to allow for free flow of cerebrospinal fluid thereby improving the quality of life for the patient.

The suboccipital ligament

OBJECTIVE A fibrous structure located dorsal to the dura at the posterior craniocervical junction stretches horizontally between the bilateral occipital condyles and the upper borders of the C-1 laminae. Partially covered by the occipital bone, this structure is always encountered when the bone is removed from the foramen magnum rim during approaches to the posterior cranial fossa. Although known to surgeons, this structure has not been defined, studied, or named. The most appropriate name for this structure is "the suboccipital ligament," and a detailed rationale for this name is provided. METHODS This 3-year-long study included 10 cadaveric specimens and 39 clinical patients: 31 consecutive surgically treated patients with Chiari Type I malformations (CM-I subgroup) and 8 other patients with posterior fossa pathologies (non-CM-I subgroup). The dimensions were defined, the function of this ligament was hypothesized, size and histological composition were compared between patient subgroups, and its origin and relationship to the surrounding structures were analyzed. Possible statistical differences in the parameters between the 2 groups were also evaluated. RESULTS The suboccipital ligament consists of horizontally oriented hyaline fibers and has a median length of 35 mm, height of 10 mm, and thickness of 0.5 mm. These dimensions are not significantly different between the CM-I and non-CM-I patients. The median age of the patients was 43 years, with CM-I patients being significantly younger (median 35 years) than non-CM-I patients (median 57 years). There was no statistically significant difference in weight, height, and body mass index between patient subgroups. There was no significant correlation between the body mass index or height of the patients and the dimensions of the ligament. No statistically significant differences existed between the subgroups in terms of smoking history, alcohol consumption, and the presence of diabetes mellitus, hypertension, hydrocephalus, or headaches. The ligament tissue in the CM-I patients was disorganized with poorly arranged collagen bands and interspersed adipose tissue. These patients also had more hyalinized fibrosis and showed changes in the direction of fibers, with hyaline nodules ranging from 0 to 2+. The result of the histological evaluation of the suboccipital ligament for hyaline nodules, calcification, and ossification was graded as 2+ if present in 3 or more medium-power magnification fields (MPFs); 1+ if present in 1-2 MPFs; and 0, if present in less than 1 MPF. Histological examination of the ligaments showed structural differences between CM-I and non-CM-I patients, most notably the presence of hyaline nodules and an altered fiber orientation in CM-I patients. CONCLUSIONS The suboccipital ligament extends between the occipital condyle and the superior edge of the C-1 lamina, connecting the contralateral sides, and appears to function as a real ligament. It is ventral to the occipital bone, which covers approximately two-thirds of the height of the ligament and is loosely attached to the dura medially and more firmly laterally. Because of its distinctive anatomy, characteristics, and function, the suboccipital ligament deserves its own uniform designation and name.

Closing the dura: dural hitching versus surgicel and tisseel overlay graft in craniocervicaldecompression for Chiari 1 malformation

BACKGROUND

This study compares dural hitching to surgicel and tisseel overlay graft following craniocervical decompression and C1 laminectomy with simple durotomy for Chiari I malformation. Outcome measures were syrinx decompression, headache resolution and complication rates.

METHODS

A retrospective analysis of case notes was conducted. Patients who had undergone craniocervical decompression (CCD) were grouped by method of dural closure. Outcomes compared were rates of syrinx decompression, headache resolution, and post-operative complications. Statistical analysis was conducted using SPSS v20.

RESULTS

We identified 32 adult patients for inclusion in this study. 53.1% (n = 17) had asyrinx, and 78.1% (n = 25) had a pre-operative headache. All were treated with suboccipital craniectomy, C1 laminectomy (with or without C2 laminectomy), and durotomy. The dura was either left open by dural hitching (n = 23) or closed with surgicel and tisseel overlay graft (n = 9). We found a statistically significant association between the method of dural closure and the rate of syrinx resolution. Resolution occurred in 91.7% (n = 11) of the hitching group, compared to 20.0% (n = 1) of the overlay graft group: Χ²(1) = 5.6, p = .018. There were no statistically significant differences between the two groups in the rates of headache resolution or other complications.

CONCLUSIONS

In patients with symptomatic Chiari I malformation and associated syringomyelia, syrinx resolution is more likely if the dura is hitched open rather than closed bysurgicel and tisseel overlay graft after durotomy.

"Stealth cranioplasty:" A novel endeavor for symptomatic adult Chiari I patients with syringomyelia: Technical note, appraisal, and philosophical considerations

Aim and Objective:

In this article, we describe a novel technique of reconstruction of posterior fossa by cranioplasty with use of preshaped titanium mesh following posterior fossa decompression (PFD) for Chiari malformation type I (CMI) with syringomyelia (SM) in symptomatic adults.

Materials and Methods:

Eleven patients underwent limited PFD and expansive cranioplasty with preshaped titanium mesh, what we term as “Stealth Cranioplasty” (SCP), following arachnoid preserving duraplasty (APD) and hexagonal tenting of the duraplasty with the cranioplasty (HTDC) for the management of symptomatic adult CMI with SM. All these patients had syringes extending from 3 to >10 vertebral levels.

Results:

Seven male and four female symptomatic CMI adult patients, between age ranges of 22 and 44 years (mean 29.45 years), presented with different neurological symptoms related to CMI and SM for 6–84 months (mean 37.09 months). All the patients underwent PFD, APD followed by SCP and HTDC and were followed up for 7–54 months (mean 35.90 months). Of 11 patients, 8 patients improved according to the Chicago Chiari Outcome Scale (CCOS) with score of 13–15 while 3 patients remained unchanged with CCOS of 12, and there was no worsening. There was no complication related to Chiari surgery in any of the patients. All the patients had good reestablishment of cisterna magna. Two patients had marked reduction of syrinx while eight patients had moderate-to-mild reduction and one patient had no change of syrinx. None of the patients needed redo surgery.

Conclusion:

SCP is an effective, fruitful, and cost-effective technique for the management of symptomatic adult CMI with SM. This technique has the advantages of preventing complications and recurrences in addition to the improvement of symptoms by addressing the basic pathology.

Craniocervical spinal instability after type 1 Arnold Chiari decompression: a case report

To present and describe an unusual case of spinal instability after craniocervical spinal decompression for a type-1 Chiari malformation. Type-1 Chiari malformation is a craniocervical disorder characterized by tonsillar displacement greater than 5 mm into the vertebral canal; posterior fossa decompression is the most common surgical treatment for this condition. Postoperative complications have been described: cerebrospinal fluid leak, pseudomeningocele, aseptic meningitis, wound infection, and neurological deficit. However, instability after decompression is unusual. A 9-year-old female presented with symptomatic torticollis after cervical decompression for a type-1 Chiari malformation. Spinal instability was diagnosed; craniocervical stabilization was performed. After a 12-month follow-up, spinal stability was achieved, with a satisfactory clinical neck alignment. We present a craniocervical instability secondary to surgical decompression; clinical and radiological symptoms, and definitive treatment were described.

[External lumbar drainage with volumetric continuing infusion pump in patients with cerebrospinal fluid leak. A case series]

OBJECTIVE

To describe the incidence and complications arising in a number of cases of patients with cerebrospinal fluid leak treated by external lumbar drainage with infusion pump (IP) volumetric continuous from 2001 to 2014. Quantify cerebrospinal fluid leak closed by lumbar drainage with IP.

METHODS

Retrospective descriptive case series study.

POPULATION

patients undergoing transsphenoidal pituitary surgery, Chiari surgery and laminectomy, that developed postoperative cerebrospinal fluid leak treated with continuous external lumbar drainage by IP.

VARIABLES

age, sex, type of intervention, variables related to the practice of the pump and complications. Average and medians were calculated for quantitative variables, frequencies and percentages for qualitative.

RESULTS

Sample: 11 subjects. Incidence in running IP: disconnection, occlusion and acoustic alarm activation. Most frequently complication is headache; a case of pneumocephalus.

DISCUSSION

The small number of subjects and the heterogeneity of these do not allow for comparison or establishing associations between variables. The resolution of the cerebrospinal fluid leak with continuous IP is lower in this study than others, and may be influenced by the small number of subjects. It should be noted the frequent activation of the pump alarm for no apparent cause.

IMPLICATIONS FOR PRACTICE

Protocol would be developed for preparing the IP team to reduce the acoustic alarm activation, and would make a prospective multicenter study.

Cough-Associated Changes in CSF Flow in Chiari I Malformation Evaluated by Real-Time MRI

BACKGROUND AND PURPOSE

Invasive pressure studies have suggested that CSF flow across the foramen magnum may transiently decrease after coughing in patients with symptomatic Chiari I malformation. The purpose of this exploratory study was to demonstrate this phenomenon noninvasively by assessing CSF flow response to coughing in symptomatic patients with Chiari I malformation by using MR pencil beam imaging and to compare the response with that in healthy participants.

MATERIALS AND METHODS

Eight symptomatic patients with Chiari I malformation and 6 healthy participants were studied by using MR pencil beam imaging with a temporal resolution of ∼50 ms. Patients and healthy participants were scanned for 90 seconds (without cardiac gating) to continuously record cardiac cycle-related CSF flow waveforms in real-time during resting, coughing, and postcoughing periods. CSF flow waveform amplitude, CSF stroke volume, and CSF flow rate (CSF Flow Rate = CSF Stroke Volume × Heart Rate) in the resting and immediate postcoughing periods were determined and compared between patients and healthy participants.

RESULTS

There was no significant difference in CSF flow waveform amplitude, CSF stroke volume, and the CSF flow rate between patients with Chiari I malformation and healthy participants during rest. However, immediately after coughing, a significant decrease in CSF flow waveform amplitude (P < .001), CSF stroke volume (P = .001), and CSF flow rate (P = .001) was observed in patients with Chiari I malformation but not in the healthy participants.

CONCLUSIONS

Real-time MR imaging noninvasively showed a transient decrease in CSF flow across the foramen magnum after coughing in symptomatic patients with Chiari I malformation, a phenomenon not seen in healthy participants. Our results provide preliminary evidence that the physiology-based imaging method used here has the potential to be an objective clinical test to differentiate symptomatic from asymptomatic patients with Chiari I malformation.

Clinical Outcome Measures in Chiari I Malformation

Chiari malformation type 1 (CM-I) is a common and often debilitating neurologic disease. Reliable evaluation of treatments has been hampered by inconsistent use of clinical outcome measures. A variety of outcome measurement tools are available, although few have been validated in CM-I. The recent development of the Chicago Chiari Outcome Scale and the Chiari Symptom Profile provides CM-I-specific instruments to measure outcomes in adults and children, although validation and refinement may be necessary.

Sudden onset of Chiari malformation type 1 in a young child after trauma

INTRODUCTION

Chiari 1 malformation is a rare craniovertebral junction malformation accounting up to 1 case in every 1000 newborns per year. It is characterized by herniation of cerebellar tonsils below the foramen magnum sometimes with syringomyelia. Usually, patients have a long history of slowly progressive neurological symptoms. Uncommonly, Chiari 1 malformation could present with a sudden onset, also after trauma. Few cases are reported about young children.

METHODS

The authors report a case of a 6-month child with symptoms at onset after a mild trauma. The pertinent literature is reviewed.

CONCLUSIONS

Symptoms of Chiari 1 malformation are usually slowly progressive. Few cases have been reported of the sudden onset of symptoms, some of these after trauma. In young children, the clinical setting could be insidious and potentially lethal. A sudden onset of Chiari 1 malformation must be considered as a consequence of trauma, usually after performing a brain MRI. Management of these cases is still controversial, and surgery may be indicated in managing symptoms; however, it seems to not affect clinical outcome.

Craniovertebral Junction Instability in the Setting of Chiari I Malformation

This article addresses the key features, clinical presentation, and radiographic findings associated with craniovertebral junction instability in the setting of Chiari I malformation. It further discusses surgical technique for treating patients with Chiari I malformation with concomitant craniovertebral junction instability, focusing on modern posterior rigid instrumentation and fusion techniques.

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.

Chiari malformation type I with cervicothoracic syringomyelia masquerading as bibrachial amyotrophy: a case report

INTRODUCTION

Clinical presentation of syringomyelia can mimic a variety of neuromuscular disorders. A misdiagnosis can result in progressive pressure on the spinal cord, causing the development of severe irreversible neurologic deficits.

CASE PRESENTATION

We report the very unusual case of a 50-year-old Latino man who developed severe distal muscle atrophy and bulbar dysfunction as a result of Chiari malformation type I with chronic cervicothoracic syringomyelia.

CONCLUSION

Syringomyelia is a potentially serious neurologic condition with symptoms that can mimic other neuromuscular disorders. Severe untreated cases can result in irreversible spinal cord injury. Prompt diagnosis with magnetic resonance imaging is important in both establishing diagnosis and directing further surgical management.

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

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

The case for duraplasty in adults undergoing posterior fossa decompression for Chiari I malformation: a systematic review and meta-analysis of observational studies

BACKGROUND

Posterior fossa decompression is carried out to improve passage of cerebrospinal fluid (CSF) in patients with symptomatic Chiari 1 malformations (CM1), but the extent and means of decompression remains controversial. Dural opening with subsequent duraplasty may contribute to clinical outcome, but may also increase complication risk. The aim of this systematic review and meta-analysis is to assess the effects of durotomy with subsequent duraplasty on clinical outcome in surgical treatment of adults with CM1.

DATA SOURCES AND STUDY ELIGIBILITY CRITERIA

We systematically searched MEDLINE, Embase and CENTRAL, and screened references in relevant articles and in UpToDate. Publications with previously untreated adults (>15 years) with CM1 with or without associated syringomyelia, treated in the period 1990-2013 were eligible.

INTERVENTIONS

Posterior fossa decompression with duraplasty (PFDD group) was compared to posterior fossa decompression with bony decompression alone (PFD group).

RESULTS

The search retrieved 233 articles. After the review we included 12 articles, but only 4 articles included posterior fossa decompression with both techniques. Only 2 out of 12 studies were prospective. The odds ratio (OR) for reoperation was 0.15 (95% CI 0.05-0.49) in the PFDD group compared to PFD (p=0.002). The OR of clinical failure at follow-up was 1.06 (95% CI 0.52-2.14) for PFDD compared to PFD (p=0.88). There was also no difference in syringomyelia improvement between techniques (p=0.60). The OR for CSF-related complications were 6.12 (95% CI 0.37-101.83) for PFDD compared to PFD (p=0.21).

CONCLUSION

This systematic review of observational studies reveals higher reoperation rates after bony decompression alone, but clinical improvement was not higher after primary decompression with duraplasty. There are so far no high-quality studies that offer guidance in the choice of decompressive technique in adult CM1 patients. We think that a randomized controlled trial on this topic is both needed and feasible.

External validation of the Chicago Chiari Outcome Scale

OBJECT

Historically, assessment of clinical outcomes following surgical management of Chiari malformation Type I (CM-I) has been challenging due to the lack of a validated instrument for widespread use. The Chicago Chiari Outcome Scale (CCOS) is a novel system intended to provide a less subjective evaluation of outcomes for patients with CM-I. The goal of this study was to externally validate the performance of the CCOS.

METHODS

Patients undergoing surgery for CM-I between 2001 and 2012 were reviewed (n = 292). Inclusion criteria for this study were as follows: 1) patients receiving primary posterior fossa decompression; 2) at least 5.5 months of postoperative clinical follow-up; and 3) patients ≤ 18 years of age at the time of surgery. Outcomes were evaluated using the CCOS, along with a "gestalt" impression of whether patients experienced significant improvement after surgery. A subgroup of 118 consecutive patients undergoing operations between 2008 and 2010 was selected for analysis of interrater reliability (n = 73 meeting inclusion/exclusion criteria). In this subgroup, gestalt and CCOS scores were independently determined by 2 reviewers, and interrater reliability was assessed using the intraclass correlation coefficient (ICC) and kappa (κ) statistic.

RESULTS

The median CCOS score was 14, and 67% of patients had improved gestalt scores after surgery. Overall, the CCOS was effective at identifying patients with improved outcome after surgery (area under curve = 0.951). The interrater reliability of the CCOS (ICC = 0.71) was high, although the reliability of the component scores ranged from poor to good (ICC 0.23-0.89). The functionality subscore demonstrated a low ICC and did not add to the predictive ability of the logistic regression model (likelihood ratio = 1.8, p = 0.18). When analyzing gestalt outcome, there was moderate agreement between raters (κ = 0.56).

CONCLUSIONS

In this external validation study, the CCOS was effective at identifying patients with improved outcomes and proved more reliable than the authors' gestalt impression of outcome. However, certain component subscores (functionality and nonpain symptoms) were found to be less reliable, and may benefit from further definition in score assignment. In particular, the functionality subscore does not add to the predictive ability of the CCOS, and may be unnecessary. Overall, the authors found the CCOS to be an improvement over the previously used assessment of outcome at their institution.

Effect of symptomatic pseudomeningocele on improvement in pain, disability, and quality of life following suboccipital decompression for adult Chiari malformation Type I

Object

Suboccipital decompression is a common procedure for patients with Chiari malformation Type I (CMI). Published studies have reported complication rates ranging from 3% to 40%, with pseudomeningocele being one of the most common complications. To date, there are no studies assessing the effect of this complication on long-term outcome. Therefore, the authors set out to assess the effect of symptomatic pseudomeningocele on patient outcomes following suboccipital decompression for CM-I.

Methods

The study comprised 50 adult patients with CM-I who underwent suboccipital craniectomy and C-1 laminectomy with or without duraplasty. Clinical presentation, radiological studies, operative variables, and complications were assessed for each case. Baseline and 1-year postoperative patient-reported outcomes were assessed to determine improvement in pain, disability, and quality of life. The extent of improvement was compared for patients with and without development of a postoperative symptomatic pseudomeningocele.

Results

A symptomatic pseudomeningocele developed postoperatively in 9 patients (18%). There was no difference with regard to clinical, radiological, or operative variables for patients with or without a postoperative pseudomeningocele. Patients without a pseudomeningocele had significant improvement in all 9 patient-reported outcome measures assessed. On the other hand, patients with pseudomeningocele only had significant improvement in headache (as measured on the Numeric Rating Scale) and headache-related disability (as measured on the Headache Disability Index) but no improvement in quality of life. Twenty-nine (71%) of 41 patients without a pseudomeningocele reported improvement in health status postoperatively compared with only 3 (33%) of 9 patients with a postoperative pseudomeningocele (p = 0.05).

Conclusions

Surgical management of CM-I in adults provides significant and sustained improvement in pain, disability, general health, and quality of life. Development of a postoperative symptomatic pseudomeningocele has lingering effects at 1 year, and it significantly diminishes the overall benefit of suboccipital decompression for CM-related symptoms. Further research is needed to accurately predict which patients may benefit from decompression alone without duraplasty.

A case of bilateral uveitis and optic disc swelling with Chiari I malformation

We report a case of bilateral uveitis and optic disc swelling with Chiari I malformation. A 16-year-old girl was admitted to our clinic due to conjunctival hyperaemia and blurred vision in her right eye. Ophthalmologic and systemic examinations were performed. Visual acuity was 0.7 (OD) and 1.0 (OS). Bilateral optic disc swelling was observed. Fluorescein angiography demonstrated bilateral retinal vasculitis as well as optic disc hyperflourescence due to leakage. Laboratory examinations were within normal limits. Cranial magnetic resonance venography imaging revealed neither cranial mass nor cerebral venous thrombosis but a Chiari I malformation. The patient was started oral cetazolamid, topical and oral corticosteroids. After six months follow-up, bilateral optic disc swelling was resolved completely and visual acuity was 1.0 in both eyes. Optic disc swelling may be associated with intraocular inflammation; however, patients with bilateral optic disc swelling should be suspected of having an accompanying intracranial pathology.