Surgical Outcomes of Adult Chiari Malformation Type 1: Experience at a Tertiary Institute.

Meliha Gündağ Papaker,İrfan Çınar,Anas Abdallah

doi:10.7759/cureus.17876

Abstract

BackgroundChiari type I malformation (CM1) is a herniation of the caudal cerebellum and/or medulla oblongata into the upper spinal canal, occurring in pediatric and adult populations. We aimed to analyze the surgical outcomes of adult patients with CM1 consecutively treated with a posterior fossa decompression and duraplasty (PFDD) in a tertiary institution.Patients and methodsWe retrospectively reviewed the medical charts of 45 adult patients with CM1 who underwent PFDD at the Neurosurgery Department of our institution between January 2012 and December 2017. Radiological evaluation was based on pre- and postoperative syrinx/cord ratio, syrinx length, and regression of the ectopic cerebellar tonsils on coronal and sagittal magnetic resonance imaging (MRI) images, and clinical assessment of the patients was performed with the Chicago Chiari Outcome Scale (CCOS).ResultsOf the 45 patients included in the study, 25 (four men, 21 women) were diagnosed with symptomatic CM1 with an age average of 36.6±11.4 (18-66) years. Headache was the most common symptom (72.0%), while pinprick losses were prevalent in 13 (52.0%) patients. The mean postoperative CCOS score was 14.7±2.0 (8-16). Symptoms improved in 20 patients (80.0%) at the last follow-up. The mean regression in ectopic tonsils on midsagittal and coronal images were 9.1±1.8 (range: 0-16.5) mm and 8.3±1.2 (0-12.0) mm, respectively (p<0.05). The syrinxes had regressed completely or significantly in 7 (87.5%) of eight patients with syrinx.ConclusionOur findings showed that PFDD is sufficient to relieve most of the major symptoms and resolve the syrinx cavity without additional surgical interventions. The CCOS keeps its measurability of assessment of the clinical outcomes. A reliable radiological evaluation should be performed on midsagittal and coronal MRI images.

Highlights

Chiari malformation type I (CM1) can be diagnosed incidentally with magnetic resonance imaging (MRI)
We retrospectively reviewed the medical charts of 45 adult patients with CM1 who underwent posterior fossa decompression and duraplasty (PFDD) at the Neurosurgery Department of our institution between January 2012 and December 2017
Radiological evaluation was based on pre- and postoperative syrinx/cord ratio, syrinx length, and regression of the ectopic cerebellar tonsils on coronal and sagittal magnetic resonance imaging (MRI) images, and clinical assessment of the patients was performed with the Chicago Chiari Outcome Scale (CCOS)

Summary

Introduction

Chiari malformation type I (CM1) can be diagnosed incidentally with magnetic resonance imaging (MRI). While there is no consensus regarding the mechanism to identify the association between syrinx cavity and CM1, it is commonly assumed that this can be attributed to the obstruction at the level below the fourth ventricle in the subarachnoid space can impair the flow of the cerebrospinal fluid (CSF) in the central canal and the compression at the foramen magnum level that prevents it at the craniocervical junction [1,4,5,6]. Chiari type I malformation (CM1) is a herniation of the caudal cerebellum and/or medulla oblongata into the upper spinal canal, occurring in pediatric and adult populations. We aimed to analyze the surgical outcomes of adult patients with CM1 consecutively treated with a posterior fossa decompression and duraplasty (PFDD) in a tertiary institution

Objectives

Methods

Results

Conclusion