Outcomes of Dura Splitting Decompression Versus Posterior Fossa Decompression With Duraplasty in the Treatment of Chiari I Malformation: A Systematic Review and Meta-analysis

A comparative analysis of neuroendoscopic foramen magnum decompression versus traditional open surgery for Chiari Malformation Type I

PURPOSE

Chiari Malformation Type I (CM1) is characterized by the downward displacement of the cerebellar tonsils below the foramen magnum. The standard surgical treatment for CM1 is foramen magnum decompression and atlas laminectomy (FMD-AL). However, there is a growing interest in exploring minimally invasive techniques, such as neuroendoscopically assisted FMD-AL, to optimize surgical outcomes. The aim is to present the results of the less invasive neuroendoscopic-assisted system application as an alternative to decompression surgery in patients with CM-1 with/without syringomyelia.

PATIENTS AND METHODS

A retrospective analysis was conducted on 76 patients with CMI who underwent either neuroendoscopic-assisted FMD-AL (n = 23) or open surgery (n = 53). Preoperative and postoperative assessments were performed, including pain levels, functional assessment, outcome and serum creatinine kinase (CK) levels. Surgical parameters and radiological imaging were also evaluated and compared.

RESULTS

Both surgical groups showed improvements in pain levels and increase in postoperative CK levels. There were no statistically significant differences between the groups in terms of postoperative JOA scores, VAS scores, CCOS, or syrinx resolution. However, the neuroendoscopic group had significantly lower CK levels, shorter hospital stays, less blood loss, and shorter operation times compared to the open surgery group, indicating reduced muscle damage and potential benefits of the neuroendoscopic assisted approach.

CONCLUSION

Both neuroendoscopy and open surgery groups can effectively alleviate symptoms and improve outcomes in patients with CM1. The neuroendoscopic assisted technique offers the advantage of reduced muscle damage and shorter hospital stays. The choice of surgical technique should be based on individual patient characteristics and preferences.

LEVEL OF EVIDENCE

3 (Retrospective case-control study) according to using the Oxford Centre for Evidence-Based Medicine (CEBM) Table.

Individualized surgical treatment of Chiari 1 malformation: A single-center experience

OBJECTIVE

To present our experience with an individualized surgical approach to treat Chiari malformation type 1.

METHODS

Based on (1) neurological symptoms, (2) the existence and extent of a syrinx and (3) the degree of the tonsillar descent we performed four types of approaches on a case-by-case basis in 81 patients: (1) foramen magnum decompression (FMD) with dura splitting (FMDds); (2) FMD with duraplasty (FMDdp); (3) FMD with duraplasty and tonsillar manipulation (FMDao); and (4) tonsillar resection/reduction (TR). Patient characteristics, Chiari Severity Index (CSI), fourth ventricular roof angle (FVRA) and Chicago Chiari Outcome Scale (CCOS) were analyzed.

RESULTS

CCOS was between 13 and 16 points in 8/11 (73 %) patients after FMDds, 38/45 (84 %) patients after FMDdp, and 24/24 (100 %, one patient lost to follow-up) patients after TR. We experienced an overall complication rate of 13.6 % (11/81) in this series, whereas seven of these eleven complications (64 %) occurred in the FMDao group and the complication rate increased with the invasiveness of the approach (0 % FMDds; 4 % FMDdp; 12 % TR).

CONCLUSION

Given the clear correlation between the extend of the approach and the complication rate the least invasive approach necessary to achieve clinical improvement should be selected. Due to the high complication rates, FMDao should not be used as a treatment option. The severity of the tonsillar descent, basilar invagination and current CM1 scores could be used to aid in the approach selection.

Foramen magnum decompression for Chiari malformation type I - UK surgical practice

Background: Symptomatic Chiari 1 malformation (CM1) is a common condition in Neurosurgery. Surgery involves hindbrain decompression and restoration of CSF flow through different surgical approaches. No Class 1 evidence exists to suggest the superiority of any of the surgical techniques.Aims: To investigate current surgical practice for symptomatic CM1 patients in the United Kingdom (UK) and determine the willingness to participate in a randomised controlled trial (RCT) comparing different surgical techniques.Methods: An electronic survey was sent to consultant members of the Society of British Neurological Surgeons and the British Chiari-Syringomyelia Group. The questions covered pre-operative and intra-operative management, presence of equipoise/uncertainty in optimal technique and willingness to participate in an RCT.Results: 98 responses were received. 67% operate on adults. 30% on adult and paediatric patients. There is variation in routine pre-operative use of: ICP monitoring (18%), flexion/extension x-rays (16%), venography (20%) and ophthalmology assessment (26%). 18% of neurosurgeons would not offer foramen magnum decompression when the presenting symptom is only refractory cough/sneeze headache. 15% routinely perform bony decompression alone in adults vs 8% in children. In 68% of adult cases, durotomy is performed routinely (46% of them leave the dura open, 54% perform a type of duroplasty) and 16% routinely resect the cerebellar tonsils. Only 17% leave the dura open in children. The most common indicators for durotomy are syringomyelia and intra-operative ultrasound findings. 61% believe there is equipoise/uncertainty in the optimal strategy for decompression and would be willing to participate in an RCT. Comments also mention the heterogeneity of CM1 and that treatment should be tailored to each patient.Conclusion: There is wide variation in pre- and intra-operative management of CM1 patients in the UK and the majority of neurosurgeons would be willing to participate in an RCT comparing bony decompression alone vs dural opening with/without duroplasty.