Chiari 1 malformation management: the Red Cross War Memorial Hospital approach Abstract Purpose In this paper, we aimed to review our institutional opinions and experience with Chiari 1 malformation management to determine physician practice and outcomes. Methods Discussion between 3 clinicians about practice preferences and the management of Chiari 1 worldwide. Retrospective review of clinical cases over a 10-year period (2009–2018). Results Although there are some minor differences between clinicians in our practice, our approach is broadly similar. We treat incidental Chiari 1 malformations conservatively, with clinical and radiological surveillance, reserving intervention for patients who develop clinical signs or radiological deterioration. We prefer surgical intervention for patients with typical symptoms or a Chiari 1 malformation with radiological progression. If symptoms are atypical, we prefer surveillance. Our preferred operation is a conservative suboccipital craniectomy with expansion duraplasty and adhesiolysis. Our operative complication rate was low and there was no mortality or major morbidity in our series. Surveillance for incidentally discovered Chiari 1 malformations has been a safe practice in our experience. Conclusion Clinical practice among three clinicians in our institution is broadly consistent. We have a conservative approach to Chiari 1 malformation management and our approach appears to have a low morbidity.

Management of Chiari I malformation in children: personal opinions Abstract Purpose This manuscript describes our management philosophy of Chiari I malformation in children based on a single neurosurgeon’s personal experience. Methods Based on 61 infants and children with Chiari I malformation treated from 2007 to 2017, typical symptoms, surgical indications, types of surgery, and evaluation of surgical decompression are reviewed. Results Sixty-one patients had 69 decompressions, with 90% having symptom improvement. Seven (11.5%) needed reoperation, 1 of which needed 2 reoperations for recurrence. The recurrence rates were 20% (5 of 25) after dural scoring and 5.6% (2 of 36) after duraplasty (p = 0.1116, Fisher’s exact test). Six (16%) of 36 patients developed pseudomeningocele or CSF leak. Conclusions We recommend surgical intervention for Chiari I malformation for clearly symptomatic patients and those with significant hydromyelia regardless of symptoms. A bony decompression with dural scoring is recommended for patients with typical occipital headaches with a lesser degree of tonsillar descent, while an expansile duraplasty is standard for those with high-grade tonsillar descent, medullary kink, or hydromyelia. Intraoperative ultrasound is often helpful to ensure the adequacy of the decompression. Most patients will have improvements in symptom and imaging after either type of decompressive surgery.

“Management: opinions from different centers”—the Sankt Augustin experience Abstract Objective In this “how we do it” survey, we review our management regimen of symptomatic CM1 and provide an analysis of our institutional case series of “bony only” decompression of the craniocervical junction without dural opening. Methods In regard to the latter clinical symptomatology, neurological status, electrophysiology data, and pre- and post-surgical MRI were analyzed. Surgery was performed in standard fashion under IOM, evaluated by intraoperative ultrasound. Results We reviewed 22 patients (mean age at surgery 13 ± 7 years; 11 female, 11 male). Neck pain, occipital headaches, sensory symptoms, and dizziness were the predominating symptoms; 9% had central apnea, 5 patients had scoliosis, and 2 patients had a history of premature synostosis. On MRI, preoperative mean tonsillar herniation was 16.55 ± 6.19, compared to 14.25 ± 6.75 after surgery. About half of patients with syringomyelia (n = 11) experienced imagining improvement after surgery. Patients with neck pain, occipital headaches, dizziness, and sensory abnormalities benefited most from surgery. Of the 6 cases that presented with pathological SSEPs, 4 exhibited improved measurements after surgery. There were no postoperative complications. Conclusion To conclude bony decompression for CM1 resulted in clinical and imaging wise improvement and can be viewed as a safe first-lane option for symptomatic CM1.

Results of the surgical treatment in children with Chiari malformation type I Abstract Purpose Our study aimed to evaluate the quality of life of the patients operated due to Chiari malformation type 1 (CM-1) in the Department of Pediatric Neurosurgery, Medical University of Silesia in Katowice. Methods We performed a retrospective analysis of 11 patients diagnosed with CM-1 who were treated in our center in the years 2007 to 2016. There were 6 female and 5 male individuals. Short-term evaluation of the outcome was based on comparison of the presenting symptoms and radiological images before and after the surgical treatment. Long-term follow-up was carried out using survey questionnaires based on the Chicago Chiari Outcome Scale (CCOS) devised originally by Aliaga et al. Results Patients, based on their CCOS score were divided into three groups marked as “improved,” “unchanged,” and “worse,” depending on a range of CCOS score: 13–16, 9–12, 4–8, respectively. The outcome of patients was as follows: 6 patients (55%) were evaluated as improved, and 5 (45%) as unchanged. No patient was classified as worse after surgery. Significant negative Spearman’s correlation was found between the CCOS score and patients’ age at the time of surgery (R = − 0.85, p = 0.0009). Conclusions The decision of whether to operate pediatric patients with CM-1 should be considered very carefully. In our department, the main indication for surgery was the occurrence of clinical symptoms. Our study revealed that in the symptomatic patients, surgery improves their quality of life measured with CCOS.

Surgery for Chiari 1 malformation: the Lille experience Abstract Purpose Decision-making in chronic tonsillar herniation (CTH) in children is complicated because many cases are diagnosed incidentally; on the other hand, its clinical impact may be underestimated. Furthermore, its surgical management is controversial. Methods In the present review, we tried to design a semi-quantitative approach to diagnosis, defining presenting symptoms as compatible, suggestive, or differential diagnoses. We expose our rationale for surgery. We review our experience with extensive posterior fossa decompression (PFD) with systematic dural opening and low threshold for tonsil resection. The aim is to achieve uncontroversial anatomical decompression. Results We operated 117 children during the last 10 years. Seventeen had complications, mostly hydraulic and minor; although most resolved without consequences, one patient died of unexplained cerebral vasospasm. At last control, 97% were clinically improved. No patient required reoperation for PFD. Conclusion With proper patient selection, extensive PFD is a very efficient operation.

Management: opinions from different centers—the Istituto Giannina Gaslini experience Abstract Purpose Describe presentation and management of Chiari type 1 malformation. We report our surgical case series proposing a decision making scheme for helping surgeons decide which surgical procedure to perform and when. Methods We retrospectively examined a series of surgically treated patients with Chiari type 1 malformation. Treatment of associated anomalies, surgical complications, and need for reintervention for insufficient decompression at first surgery are discussed. Results A total of 172 patients have been surgically treated for Chiari type 1 malformation at the Neurosurgery Unit of IRCCS Giannina Gaslini Children Hospital of Genoa, Italy, in a period between 2006 and 2017. The first treatment addressing Chiari type 1 malformation was bone and ligamentous decompression alone in 104 patients (65%), associated with dural delamination in 3 patients (1.9%) and associated with duraplasty with autologous graft in 53 patients (33.1%). Postoperative complications occurred in 5 patients (2.9%). Reintervention for insufficient decompression at follow-up was needed in 6 patients (3.5%). Conclusions Surgical decompression of the posterior cranial fossa (PCF) is indicated in symptomatic patients while asymptomatic patients must be followed in a wait and see fashion. Different types of surgical decompression of different invasiveness have been proposed from only bone and ligamentous decompression to coagulation of cerebellar tonsils. Intraoperative ultrasonography is a useful tool to define when a decompression is sufficient. We did not find correlation between the need for reintervention for insufficient decompression and different invasiveness of the techniques. We believe that this finding suggests that our proposed scheme leads to the best tailored treatment for the single patient.

Complex Chiari malformation: using craniovertebral junction metrics to guide treatment Abstract The complex Chiari, characterized by abnormal craniocervical bony anatomy in addition to Chiari tonsillar herniation, is a relatively recent addition to the concepts surrounding the Chiari literature. The primary findings of complex Chiari include craniocervical kyphosis and retroflexed odontoid, both of which can be described with radiographic measurements. This manuscript will outline the background literature regarding Chiari craniocervical morphometrics and supply an algorithm for the general management of complex Chiari patients.

Graham Fieggen, ISPN president 2017–2018

Introduction to the special edition from the Editors Pediatric Chiari I malformation—searching for clarity amidst myth, misnomer, and misunderstanding

Should we stop using the term “malformation” for Chiari type I?