Duraplasty Type as a Predictor of Meningitis and Shunting After Chiari I Decompression

Chiari I Deformity: Beyond 5 mm below the Foramen Magnum

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

Surgical Outcomes in Chiari 1 and Chiari 1.5 Malformation Treated by Posterior Fossa Reconstruction: A Comprehensive Analysis of 110 Pediatric Cases and Literature Review

Background/Objectives: The management of Chiari malformations (CMs) remains a clinical challenge and a topic of great controversy. Results may vary between children and adults. The purpose of the current single-center study is to critically assess the one-year surgical outcomes of a cohort of 110 children with CM-1 or CM-1.5 who were treated using "posterior fossa reconstruction" (PFR), a surgical technique described in 1994 that has since been used in both adults and children. We also review the literature and discuss the possible causes of the drawbacks and pitfalls in children in whom PFR was ineffective in controlling the disease. Methods: The present cohort was selected from a prospective registry of adults and children with CMs collected since 2006. Patients included in this study were selected from a group of children with CMs who were operated on in our Pediatric Neurosurgical Unit between 1 January 2007 and 31 November 2023. Surgical outcome was defined based on clinical and neuroradiological results as very good, good, or bad. Results: The mean age of our child cohort was 9.9 ± 4.7 years, with 54 girls (49%) and 56 boys (51%). Sixty-six children had CM-1 (60%) while forty-four had CM-1.5 (40%). Following surgery, there was no neurological worsening or death among the children. Most children (70%) had an uneventful recovery and were discharged home on average one week after surgery. However, in 33 children (30%), we recorded at least one postoperative adverse event. Aseptic meningitis syndrome was the most frequent adverse event (n = 25, 22.7%). The final surgical outcome was evaluated one year after PFR by using both clinical and neuroradiological results. The one-year surgical outcome was excellent in 101 children (91.9%), good in 5 (4.5%), and bad in 4 (3.6%). Conclusions: PFR significantly enlarges the volume of the posterior fossa and recreates a CSF environment that generates buoyancy of the cerebellum, with a high percentage of excellent and good clinical results evaluated one year post-surgery.

Long-term outcome of operated Chiari I patients between 2005 and 2020 in Eastern Finland

PURPOSE

The purpose of our study was to examine the long-term outcomes of operated Chiari malformation type 1 (CM1) patients and evaluate whether different duraplasty techniques affected outcome after surgery in Kuopio University Hospital catchment area.

METHODS

In this retrospective study, a total of 93 patients were diagnosed with CM1 and underwent posterior fossa decompression surgery with or without duraplasty between 2005 and 2020. All patients' medical records were examined for baseline characteristics, surgical details, and long-term follow-up data after operation.

RESULTS

The mean age of CM1 patients was 25.9 years (SD 19.2 years), with female preponderance 69/93 (73.4%). The mean clinical follow-up time was 26.5 months (SD 33.5 months). The most common presenting symptoms were headache, symptoms of extremities, and paresthesia. Posterior fossa decompression with duraplasty was performed in 87 (93.5%) patients and bony decompression in 6 (6.5%) patients. After surgery, preoperative symptoms alleviated in 84.9% (79/93) and the postoperative syringomyelia regression rate was 89.2% (33/37) of all patients. The postoperative complication rate was 34.4% (32/93), with aseptic meningitis being the most common, 25.8% (24/93). Revision surgery was required in 14% (13/93) of patients. No significant correlation between postoperative outcome and extent of dural decompression, or type of duraplasty performed was found.

CONCLUSION

This is the largest reported series of surgically treated CM1 patients in Finland. Posterior fossa decompression is an effective procedure for CM1 symptomology. Duraplasty technique had no significant difference in complication rate or long-term outcomes.

Dural Reconstruction Materials for the Repairing of Spinal Neoplastic Cerebrospinal Fluid Leaks

Spinal tumors often lead to more complex complications than other bone tumors. Nerve injuries, dura mater defect, and subsequent cerebrospinal fluid (CSF) leakage generally appear in spinal tumor surgeries and are followed by serious adverse outcomes such as infections and even death. The use of suitable dura mater replacements to achieve multifunctionality in fluid leakage plugging, preventing adhesions, and dural reconstruction is a promising therapeutic approach. Although there have been innovative endeavors to manage dura mater defects, only a handful of materials have realized the targeted multifunctionality. Here, we review recent advances in dura repair materials and techniques and discuss the relative merits in both preclinical and clinical trials as well as future therapeutic options. With these advances, spinal tumor patients with dura mater defects may be able to benefit from novel treatments.

Application value of calcium phosphate cement in complete cranial reconstructions of microvascular decompression craniectomies

OBJECTIVE

To investigate the application value of calcium phosphate cement (CPC) in repairing cranial defects during microvascular decompression (MVD) surgery via the retrosigmoid approach.

METHODS

A retrospective study was carried out on patients who underwent MVD. According to the two different cranial reconstruction methods, patients were divided into a titanium mesh (TM) group and a CPC group. We compared in the two groups the length of postoperative hospital stay, the incidence of postoperative cerebrospinal fluid (CSF) leakage, the number of patients with suspected postoperative intracranial infection who underwent lumbar puncture, the number of patients with a definitive etiologic diagnosis of intracranial infection, and the imaging evaluation of plastic shape satisfaction.

RESULTS

Patients in the CPC group had an average hospital stay of 9.15 ± 2.00 days, shorter than that in the TM group (10.69 ± 2.86 days), P < 0.001. In the TM group, the rate of plasticity satisfaction was 70/89 (78.65%), which was significantly lower than that in the CPC group (60/66, 90.91%), P = 0.040. Among the patients with a definitive etiologic diagnosis of intracranial infection, there were eight cases in the TM group and one case in the CPC group, and the difference was statistically significant, P = 0.049.

CONCLUSIONS

CPC is another viable alternative for complete cranial reconstructions of microvascular decompression craniectomies. The use of CPC does not increase the incidence of postoperative complications, such as CSF leakage and intracranial infection, and can reduce the average length of hospital stay and the incidence of etiologic diagnosis of intracranial infection. Furthermore, the evaluation of the plastic shape is satisfactory.

Dual Dural Patch Graft With AlloDerm and DuraGen Underlay for Duraplasty in Chiari Malformation Results in Significantly Decreased Cerebrospinal Fluid Leak Complications

BACKGROUND

Grafts available for posterior fossa dural reconstruction after Chiari decompression surgery include synthetic, xenograft, allograft, and autograft materials. The reported rates of postoperative pseudomeningocele and cerebrospinal fluid leak vary, but so far, no dural patch material or technique has sufficiently eliminated these problems.

OBJECTIVE

To compare the incidence of graft-related complications after posterior fossa surgery using AlloDerm alone vs AlloDerm with a DuraGen underlay.

METHODS

We performed a retrospective single-center study of a cohort of 106 patients who underwent Chiari decompression surgery by a single surgeon from 2014 through 2021. Age, sex, body mass index, tonsillar descent, syrinx formation, type of dural graft, and follow-up data were analyzed using univariate and χ2 statistical tests.

RESULTS

The AlloDerm-only group had a percutaneous cerebrospinal fluid (CSF) leak rate of 8.6% vs a 0% rate in the dual graft group (P = .037). At initial follow-up, there was a 15.5% combined rate of pseudomeningocele formation plus CSF leak in the AlloDerm-only group vs 18.8% in the AlloDerm + DuraGen group (P = .659). However, the pseudomeningoceles were larger in the AlloDerm-only cohort (45.5 vs 22.4 mm anteroposterior plane, P = .004), and 5 patients in this group required operative repair (56%). All pseudomeningoceles resolved without reoperation in the AlloDerm + DuraGen group (P = .003).

CONCLUSION

The use of a DuraGen underlay with a sutured AlloDerm dural patch resulted in significantly fewer CSF-related complications and eliminated the need for reoperation compared with AlloDerm alone. This single-center study provides evidence that buttressing posterior fossa dural grafts with a DuraGen underlay may decrease the risk of postoperative complications.

Comparison of Dural Graft Types and Graft Fixation Methods in Chiari Malformation Type I Decompression Surgery

OBJECTIVE

Suboccipital decompression with duraplasty is being increasingly accepted for treating patients with Chiari malformation type I (CM-1). To date, the optimal duraplasty for CM-I has not been delineated. This study aims to compare the clinical and radiologic effects of duraplasty performed using 2 types of grafts and 2 graft fixation methods in 3 combinations.

METHODS

In this retrospective study, 84 consecutive decompressions with duraplasty were analyzed. Two types of grafts (nonautologous [Non-Auto G], 90.5% and autologous [Auto G], 9.5%) and 2 graft fixations (suturing [S], 31.0%; and suturing plus gluing [S + G], 69.0%) were used in 3 different combinations: Non-Auto G S: 31.0%; Non-Auto G S + G: 59.5%, and Auto G S + G: 9.5%. All patients were followed up for 3 months. Clinical results were evaluated using the Gestalt scale, and syringomyelia results were evaluated using magnetic resonance imaging.

RESULTS

According to the Gestalt scale, 82.1% of the patients showed improvement 3 months post operation, and the improvement was not related to the type of graft (P = 0.90), fixation (P = 0.90), or duraplasty (P = 0.81). Decreased syringomyelia was observed in 76.4% of the patients. It was not associated with the graft (P = 0.53), fixation (P = 0.72), or duraplasty (P = 0.80). Meningitis occurred in the Auto G S + G, Non-Auto G S + G and Non-Auto G S groups (25%, 48%, and 23.1%, respectively; P = 0.30), and their formations were not related to the k graft type (P = 0.57) or fixation (P = 0.19).

CONCLUSIONS

Autologous and nonautologous dural grafts can be performed using either sutures or sutures plus glue, as both result in similar outcomes.

Comparison of Pericranial Autograft and AlloDerm for Duraplasty in Patients With Type I Chiari Malformation: Retrospective Cohort Analysis

BACKGROUND

Pericranial autograft is a popular option for duraplasty during Chiari decompression with several theoretical advantages, but comparisons to other materials have yielded mixed results.

OBJECTIVE

To compare outcomes between pericranial autograft and AlloDerm (BioHorizons).

METHODS

Consecutive suboccipital craniectomies for patients with type I Chiari malformation (CM-I) over an 8-yr period at a single institution were identified. Exclusion criteria included revision surgeries and suboccipital decompressions without duraplasty. Outcomes included incisional cerebrospinal fluid (CSF) leakage, length of stay (LOS), wound complication, aseptic meningitis, syrinx improvement, and symptomatic improvement.

RESULTS

A total of 101 patients (70 females and 31 males) with a median (interquartile range) age of 17 yr (11-32) met the inclusion criteria. There were 51 (50%) patients who underwent duraplasty with pericranial autograft, and the remainder underwent duraplasty with AlloDerm. There were 9 (9%) patients who experienced a postoperative CSF leak. After adjusting for confounding factors, obesity (odds ratio [OR]: 4.69, 95% CI: 1.03-25.6) and use of AlloDerm (OR: 10.54, 95% CI: 1.7-206.12) were associated with CSF leak. Wound complication occurred in 8 (8%) patients but was not associated with graft type (P = .8). Graft type was not associated with LOS, syrinx improvement, or symptom improvement. Reoperations occurred in 10 patients with 4 in the autograft group and 6 in the AlloDerm group (P = .71).

CONCLUSION

In patients with CM-I, expansile duraplasty with AlloDerm was associated with greater odds of CSF leakage than pericranial autograft. Obesity was also associated with increased odds of CSF leakage.

Outcomes for various dural graft materials after posterior fossa decompression with duraplasty for Chiari malformation type I: a systematic review and meta-analysis

OBJECTIVE

Posterior fossa decompression with duraplasty (PFDD) is often used for Chiari malformation type I (CM-I), but outcomes associated with different dural graft materials are not well characterized. In this meta-analysis, the authors examined complication rates and outcomes after PFDD for CM-I for autografts and four types of nonautologous grafts.

METHODS

A literature search of numerous electronic databases (Ovid Medline, Embase, Scopus, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Database of Abstracts of Reviews of Effects, Health Technology Assessment Database, NHS Economic Evaluation Database, and ClinicalTrials.gov) was performed to identify articles detailing complications for dural graft materials after PFDD. Whenever available, data were also extracted regarding the need for revision surgery, symptom changes after PFDD, and syrinx size changes after PFDD. All searches were compliant with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), Institute of Medicine, Standards for Systematic Reviews, Cochrane Handbook for Systematic Reviews of Interventions, and Peer Review of Electronic Search Strategies guidelines. There were no exclusion criteria based on patient age or presence or absence of syringomyelia.

RESULTS

The current evidence surrounding outcomes for various dural graft materials was found to be of low or very low quality. Twenty-seven studies were included, encompassing 1461 patients. Five types of dural graft materials were included: autograft (n = 404, 27.6%), synthetic (n = 272, 18.6%), bovine pericardium (n = 181, 12.4%), collagen-based (n = 397, 27.2%), and allograft (n = 207, 14.2%). Autograft was associated with a significantly lower rate of pseudomeningocele compared to collagen-based grafts, allografts, and nonautologous grafts in aggregate. Autograft was also associated with the lowest rates of aseptic meningitis, infectious meningitis, and need for revision PFDD, though these associations did not reach statistical significance. No other graft comparisons yielded significant results. Autograft and nonautologous graft materials yielded similar rates of revision surgery and produced similar improvements in postoperative symptoms and syrinx size.

CONCLUSIONS

Autograft was the dural graft material that most frequently had the lowest rate of complications and was associated with significantly lower rates of pseudomeningocele compared to collagen-based graft, allograft, and nonautologous graft materials. Autografts and nonautologous grafts yielded similar outcomes for revision surgery, symptoms, and syrinx size. Large prospective studies comparing different graft materials are needed to accurately and precisely characterize outcomes for individual graft types.

Comparison of dural grafts and methods of graft fixation in Chiari malformation type I decompression surgery

Suboccipital decompression with duraplasty is a widely accepted method for treating patients with Chiari malformation type I. However, important details of the duraplasty technique are still controversial. This retrospective study analyzes clinical and radiological outcomes after surgery depending upon the type of graft and methods of graft fixation. Seventy consecutive decompressions with duraplasty were analyzed. Two types of grafts, nonautologous (Non-AutoG; 60.0%) and autologous (AutoG; 40.0%), and two methods of graft fixation, suturing (S; 67.1%) and gluing (G; 32.9%), were used in four different combinations: (Non-AutoG+S: 31.4%; Non-AutoG+G: 28.6%; AutoG+S: 35.7%; AutoG+G: 4.3%) according to surgeon preference. The mean follow-up was 63.4 months. According to gestalt and Chicago Chiari Outcome Scales, satisfactory results were obtained in 72.9% and 78.6% of cases, respectively, in the long term. The outcomes were not related to the kind of graft (p = 0.44), fixation method (p = 0.89) or duraplasty pattern (p = 0.32). Decreased syringomyelia was observed in 88.9% of cases, and no associations with the kind of graft (p = 0.84), fixation method (p = 1) or duraplasty pattern were found (p = 0.96). Pseudomeningocele occurred 5 times more often in the Non-AutoG group than in the AutoG group (52.4% vs. 10.7%; p < 0.05), whereas their formations were not related to the fixation method (p = 0.34). Three cases (12.0%) required reoperation with reduraplasty. Autologous and nonautologous dural grafts can be sutured or glued with similar clinical results; however, the use of nonautologous grafts is linked with a much higher risk of pseudomeningocele formation.

Emergency Department Visits Following Suboccipital Decompression for Adult Chiari Malformation Type I

BACKGROUND

Postoperative emergency department (ED) visits following suboccipital decompression in Chiari malformation type I (CM-1) patients are not well described. We sought to evaluate the magnitude, etiology, and significance of postoperative ED service utilization in adult CM-1 patients at a tertiary referral center.

METHODS

A prospectively maintained database of CM-1 patients seen at our institution between January 1, 2006 and December 31, 2019 was used. ED visits occurring within 30 days after surgery were tracked for postoperative patients, while comparing clinical, imaging, and operative characteristics between patients with and without an ED visit. Clinical improvement at last follow-up was also compared between both groups of patients in a univariable and multivariable analysis using the Chicago Chiari Outcome Scale (CCOS).

RESULTS

In 175 surgically treated patients, 44 (25%) visited an ED in the 1-month period after surgery. The most common reason for seeking care was isolated headache (41%), and concentration disturbance at presentation was the only factor significantly associated with a postoperative ED visit (P = 0.023). The occurrence of a postoperative ED visit was independently associated with a lower chance of clinical improvement at last follow-up (adjusted odds ratio of CCOS ≥13 = 0.35, P = 0.021; adjusted odds ratio of CCOS ≥14 = 0.38, P = 0.016).

CONCLUSIONS

Adult CM-1 patients undergoing surgery at a tertiary referral center have an elevated rate of postoperative ED visits, which are mostly due to pain-related complaints. Such visits are hard to predict but are associated with worse long-term clinical outcome. Interventions that decrease the magnitude of postoperative ED service utilization are warranted.

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.