Minimally invasive foramen magnum durectomy and obexostomy for treatment of craniocervical junction–related syringomyelia in adults: case series and midterm follow-up

View More View Less
  • 1 Department of Neurosurgery, Hospital das Clínicas of University of São Paulo Medical School, São Paulo;
  • 2 Hospital Israelita Albert Einstein, São Paulo, Brazil; and
  • 3 Department of Neurosurgery, Stanford University School of Medicine, Stanford, California
Restricted access

Purchase Now

USD  $45.00

Spine - 1 year subscription bundle (Individuals Only)

USD  $369.00

JNS + Pediatrics + Spine - 1 year subscription bundle (Individuals Only)

USD  $600.00
Print or Print + Online


Craniocervical junction–related syringomyelia (CCJS) is the most common form of syringomyelia. Approximately 30% of patients treated with foramen magnum decompression (FMD) will show persistence, recurrence, or progression of the syrinx. The authors present a pilot study with a new minimally invasive surgery technique targeting the pathophysiology of CCJS in adult patients.


The authors retrospectively analyzed the clinical and radiological features of a consecutive series of patients treated for CCJS. An FMD and FM durectomy were performed through a 1.5- to 2-cm skin incision. Then arachnoid adhesions were cleared, creating a permanent communication from the fourth ventricle to the new paraspinal extradural cavity (obexostomy) and with the spinal subarachnoid space. The hypothesis was that the new CSF pouch acts like a pressure leak, interrupting the CCJS pathogenesis.


Twenty-four patients (13 female, 21–61 years old) were treated between 2014 and 2018. The etiology of CCJS was Chiari malformation type I (CM-I) in 20 patients (83.3%), Chiari malformation type 0 (CM-0) in 2 patients (8.3%), and CCJ arachnoiditis in 2 patients (8.3%). Two patients underwent reoperations after failed FMD for CM-I at other institutions. No major surgical complication occurred. One patient had postoperative meningitis with no CSF fistula. On postoperative MRI, shrinkage of the syrinx was seen in all patients. No patients experienced recurrence of the CCJS. No patient required a subsequent operation. The mean duration of surgery was 72 ± 11 minutes (mean ± SD), and blood loss was 35–80 ml (mean 51 ml). Follow-up ranged from 12 to 58 months. The average overall improvement in modified Japanese Orthopaedic Association scores was 10% (p < 0.001). The Odom scale showed that 19 patients (79.1%) were satisfied, 4 (16.7%) remained the same, and 1 (4.2%) reported a poor outcome. All patients experienced postoperative improvement in perception of quality of life (p < 0.001).


Minimally invasive FM durectomy and obexostomy is a safe and effective treatment for CCJS and for patients who have not responded to other treatment.

ABBREVIATIONS CCJS = craniocervical junction–related syringomyelia; CM-0 = Chiari malformation type 0; CM-I = Chiari malformation type I; FM = foramen magnum; FMD = FM decompression; MIS = minimally invasive surgery; mJOA = modified Japanese Orthopaedic Association; POD = postoperative day; SF-36 = 36-Item Short-Form Health Survey; VAS = visual analog scale.

Supplementary Materials

    • Supplemental Appendices 1 and 2 (PDF 2.64 MB)

Spine - 1 year subscription bundle (Individuals Only)

USD  $369.00

JNS + Pediatrics + Spine - 1 year subscription bundle (Individuals Only)

USD  $600.00

Contributor Notes

Correspondence Mauricio Mandel: Stanford University School of Medicine, Stanford, CA.

INCLUDE WHEN CITING Published online April 17, 2020; DOI: 10.3171/2020.2.SPINE2032.

Disclosures The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.


All Time Past Year Past 30 Days
Abstract Views 953 953 289
Full Text Views 92 92 28
PDF Downloads 59 59 27
EPUB Downloads 0 0 0