Surgical management of Chiari II malformation: a systematic review of literature.

PURPOSE: Chiari II malformation (CM-II) is a congenital malformation of the posterior fossa associated with myelomeningocele. Of the symptomatic patients, 10-33% require surgical treatment. To this date, there is not a consensus about the best surgical technique, and whether to do duroplasty. METHODS: A literature search of the PubMed database and crossed references was performed, per PRISMA guidelines. Data regarding demographic features, extent of cervicomedullary deformity, clinical presentation, surgical techniques, and clinical outcomes were extracted. Pearson's chi-squared test was applied. The p-values under 0.05 were considered statistically significant. RESULTS: Twenty studies (N = 330) were analyzed. C3 and C4 levels represented 56.4% of the lowest tonsil displacement. The most reported symptom was dysphagia/swallowing dysfunction (53.8%). Suboccipital craniectomy (SOC) and cervical spine expansion (CSE) with duroplasty were the most reported technique. Dural augmentation was performed in 57.4% of the patients. After surgery, 59.6% observed an improvement in symptoms and quality of life, 12.5% were unchanged, and 27.8% had a worsened clinical status. The mortality rate was 2.5% during the first month after surgery, and 17.4% at the last follow-up evaluation. Patients who underwent CSE presented a better clinical outcome (p = 0.002). The SOC procedure could not be correlated with symptom improvement (p = 0.06). CONCLUSION: CM-II is associated with high morbidity and mortality. An early onset symptomatic CM-II demands intervention, which provided an improvement of outcome in most patients included in this review. The best surgical technique and the exact effect of the surgical management of CM-II on mortality are not yet clear.

Posterior Fossa Decompression with or Without Duraplasty for Chiari I Malformation.

Posterior fossa decompression (PFD) with/without duraplasty is the standard surgical treatment for symptomatic CM-1. Posterior fossa decompression without duraplasty (PFD) may be associated with shorter operative times and hospital stays, fewer complications, and may yield improvements in symptoms and syrinx sizes. Posterior fossa decompression with duraplasty (PFDD) may be associated with superior long-term symptomatic improvements, larger syrinx reductions, and a lower need for revision decompression. Various dural graft materials may be used for PFDD, though the ideal type of graft has not been definitively established. Other adjunct surgical procedures may be added to PFD/PFDD given certain symptomatic or anatomical considerations.

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.

Dural augmentation approaches and complication rates after posterior fossa decompression for Chiari I malformation and syringomyelia: a Park-Reeves Syringomyelia Research Consortium study.

OBJECTIVE: Posterior fossa decompression with duraplasty (PFDD) is commonly performed for Chiari I malformation (CM-I) with syringomyelia (SM). However, complication rates associated with various dural graft types are not well established. The objective of this study was to elucidate complication rates within 6 months of surgery among autograft and commonly used nonautologous grafts for pediatric patients who underwent PFDD for CM-I/SM. METHODS: The Park-Reeves Syringomyelia Research Consortium database was queried for pediatric patients who had undergone PFDD for CM-I with SM. All patients had tonsillar ectopia ≥ 5 mm, syrinx diameter ≥ 3 mm, and ≥ 6 months of postoperative follow-up after PFDD. Complications (e.g., pseudomeningocele, CSF leak, meningitis, and hydrocephalus) and postoperative changes in syrinx size, headaches, and neck pain were compared for autograft versus nonautologous graft. RESULTS: A total of 781 PFDD cases were analyzed (359 autograft, 422 nonautologous graft). Nonautologous grafts included bovine pericardium (n = 63), bovine collagen (n = 225), synthetic (n = 99), and human cadaveric allograft (n = 35). Autograft (103/359, 28.7%) had a similar overall complication rate compared to nonautologous graft (143/422, 33.9%) (p = 0.12). However, nonautologous graft was associated with significantly higher rates of pseudomeningocele (p = 0.04) and meningitis (p < 0.001). The higher rate of meningitis was influenced particularly by the higher rate of chemical meningitis (p = 0.002) versus infectious meningitis (p = 0.132). Among 4 types of nonautologous grafts, there were differences in complication rates (p = 0.02), including chemical meningitis (p = 0.01) and postoperative nausea/vomiting (p = 0.03). Allograft demonstrated the lowest complication rates overall (14.3%) and yielded significantly fewer complications compared to bovine collagen (p = 0.02) and synthetic (p = 0.003) grafts. Synthetic graft yielded higher complication rates than autograft (p = 0.01). Autograft and nonautologous graft resulted in equal improvements in syrinx size (p < 0.0001). No differences were found for postoperative changes in headaches or neck pain. CONCLUSIONS: In the largest multicenter cohort to date, complication rates for dural autograft and nonautologous graft are similar after PFDD for CM-I/SM, although nonautologous graft results in higher rates of pseudomeningocele and meningitis. Rates of meningitis differ among nonautologous graft types. Autograft and nonautologous graft are equivalent for reducing syrinx size, headaches, and neck pain.

Surgical management of symptomatic Chiari II malformation in infants and children.

PURPOSE: Variation exists in the surgical methods employed for decompression of Chiari II malformation (CIIM), yet an evaluation of these techniques has not been performed. The purpose of this study was to assess the efficacy of bony decompression (cervical laminectomy alone versus suboccipital craniectomy with laminectomy) with or without dural augmentation for the treatment of symptomatic CIIM. METHODS: Clinical records of children 0-18 years of age who underwent surgical repair of myelomeningocele or CIIM decompression at St. Louis Children's Hospital (SLCH) from 1990-2011 were reviewed. Signs/symptoms prompting decompression, surgical technique, operative parameters, and clinical outcomes were recorded for analysis. RESULTS: Thirty-three subjects were treated at SLCH for CIIM decompression. Twenty-six subjects underwent bony decompression only (21 cervical laminectomy alone, 5 suboccipital craniectomy + cervical laminectomy) while seven underwent bony decompression with upfront dural augmentation (three cervical laminectomy alone, four suboccipital craniectomy + cervical laminectomy). Median follow up was 5.0 years (range, 3 months-19 years). Symptomatic improvement was noted in 20/33 subjects (60.6%). Sixty-two (61.5%) percent of children who underwent bony decompression had symptomatic improvement, compared with 57.1% of those with upfront dural augmentation (p = 0.37). Estimated blood loss, operative time, and length of perioperative hospital stay appeared lower in the bony decompression group but were not statistically different in this limited cohort. CONCLUSIONS: The results from this series suggest that bony CIIM decompression via tailored cervical laminectomies alone, without suboccipital craniectomy or upfront dural augmentation, is a reasonable initial management approach for decompression of symptomatic CIIM.

Craniectomía decompresiva bifrontal: nota técnica sobre el cierre dural / Bifrontal decompresive craniectomy: a technical note with reference to dural closure

La craniectomía decompresiva es una terapéutica quirúrgica utilizada en los pacientes que presenta hipertensión endocraneana refractaria al tratamiento médico. Pueden hacerse decompresivas uni o bihemisféricas, de acuerdo al patrón lesional del paciente en cuestión. La forma de realizar la duroplastia, debe ser sencilla y reglada, de forma que permita ahorrar tiempo y optimizar el uso del material biológico utilizado par la misma. En la literatura sobre craniectomías decompresivas, en general no se hace referencia a la forma de cierre dural. En la siguiente nota técnica, se describe una forma sencilla de realizar la duroplastia con periostio en la decompresiva bifrontal. Primero: luego del abordaje bicoronal en piel se corta el periostio en la línea media realizando dos colgajos simétricos con base en región temporal y reborde orbitario (RO). Segundo: craniectomía amplia con decompresión temporal. Tercero: se abre la duramadre desde temporal a la línea media (LM) y a 2 cms de llegar a ella, la incisión se hace paralela a la LM hasta alcanzar el RO. Se hacen dos incisiones de descarga, una a nivel del RO y otra donde se unen el trazo vertical y horizontal de la incisión. Cuarto: se labran dos colgajos de periostio a cada lado de la línea media, uno se sutura hacia la LM y otro hacia el sector posterior de la apertura dural. Con esta técnica sencilla se logra una buena relajación dural y excelente aprovechamiento del periostio.

Decompresive craniectomy is an accepted surgical technique for refractory intracranial hypertension. According to the lesional pattern of the patient, bifrontal or unihemispheric decompression can be made. Dural augmentation is a very important step of the surgery, so it must be done in a standard fashion in order to minimize surgical time and economize the perisoteum. In this technical note, the author describe a simple technique of dural augmentation in bifrontal craniectomy. First: after skin is reflected frontaly, two simetrical flaps of periosteum are made by cutting it at midline and reflecting it to the frontal region. Second: two bone flap are removed with decompression of the temporal region and orbital rim. Third: duramater is opened by two incisions, one parallel to midline and other following the posterior border of craniectomy. Two small incisions are made: one in the point were the two major incision founds, and the second parallel to the orbital rim. Fourth: two longitudinal periosteal flaps are made. The first is sutured parallel to midline, the second is located in the postero-inferior part of the dural opening. With this simple technique, a dural augmentation is obtained with the available periosteum.