Surgical treatment of Chiari malformation with and without syringomyelia: experience with 177 adult patients

Abstract

Surgical decompression of the posterior fossa should aim to create relatively large subarachnoid cisterns and reduce the size of the syrinx cavity. Reduction of the cerebellar tonsils by surgical means, together with duraplasty, achieves this goal and thereby improves the clinical outcome for patients with CM. An incidental observation of the study is that obesity increases the likelihood of headache in patients with CM.

Impact of body mass index on cerebellar tonsil position in healthy subjects and patients with Chiari malformation

“…Batzdorf et al 9 found that the mean BMI for 177 adult patients who underwent CM-I decompression at their institution was 26.4 kg/m 2 . Similarly, Arnautovic et al 4 reported on 60 adults who underwent CM-I decompression, and they found a mean BMI of 30.4 kg/m 2 .…”

“…3,12,19,26,28 A relatively small percentage of our patients with CM-I were symptomatic, which is consistent with previous reports of different cohorts from our institution. 26,28 Batzdorf et al 9 recently reported BMI data for 106 adult patients with CM-I who were all treated surgically. In that group, the authors found that an elevated BMI was associated with an increased likelihood of exertional headache, a symptom that was present in a majority of their patients.…”

“…15 Theoretically, elevations in ICP may exacerbate this condition and lead to an increased risk of syrinx. 9 Because an elevated BMI may be associated with increased ICP in certain cases, some authors have speculated that an elevated BMI may contribute to syrinx formation. In a series reported by Arnautovic et al, 4 the length of the syrinx was slightly shorter in 7 individuals with a normal BMI (BMI 18.5-24.9 kg/m 2 ) than that in 5 overweight individuals (BMI 25-29.9 kg/m 2 ).…”

“…First, as noted by several other groups, CM-I does not meet the usual definition of a malformation. 9,22,23 Furthermore, on the basis of recent information, the imaging diagnosis of this condition, once a straightforward matter of measuring the tonsils below the foramen magnum, is also a fair subject for debate. In this analysis, the diagnosis of CM-I via imaging was made in the usual way by determining the cerebellar tonsil position to be ≥ 5 mm below the foramen magnum.…”

“…4,9,18 We analyzed cerebellar tonsil positions and BMIs in a large series of patients of all ages who underwent MRI for any reason to explore the relationship between low tonsil position or CM-I and BMI. We found no relationship between tonsil position and BMI.…”