Posterior fossa decompression for Chiari malformation type I: clinical and radiological presentation, outcome and complications in a retrospective series of 105 procedures

  • J. De VliegerEmail author
  • J. Dejaegher
  • F. Van Calenbergh
Original article



Determining clinical and radiological characteristics, complication rates and outcome for patients undergoing posterior fossa decompression (PFD) and duraplasty for Chiari malformation type I (CM-I).

Methods and materials

Retrospective, single-university hospital study of all PFDs for CM-I between January 1995 and December 2016.


PFD was performed in 105 patients with CM-I (n = 105), of whom 62 suffered from associated syringomyelia and 37 were pediatric cases. There was a female preponderance in the syringomyelia, non-syringomyelia, pediatric and adult groups (62.9%, 65.1%, 54.1% and 69.1%, respectively). Mean age at diagnosis was higher in the syringomyelia group (32.3 versus 26.9 years, p = 0.06) and in both groups delay for diagnosis was long (33.4 and 47.1 months, p = 0.50). Headache during Valsalva maneuver and on exertion was significantly more present in the non-syringomyelia group (27.9% versus 16.1%, p < 0.0001 and 39.5% versus 11.3%, p = 0.0009); cranial nerve dysfunction and cerebellar signs did not differ significantly (p = 0.07 and p = 0.53). Spinal cord syndrome was significantly more present in the syringomyelia group (72.6% versus 25.6%, p < 0.0001). Scoliosis was present in five patients, of whom four had syringomyelia. Duraplasty was performed in 101 surgeries. For 100 patients, PFD was the primary treatment of CM-I; 2 patients had previously undergone syrinx drainage and 3 ventriculoperitoneal shunting for hydrocephalus. Only one patient presented with hydrocephalus. Duraplasty (n = 101) was complicated by CSF leak in 4.0% (n = 4), symptomatic pseudomeningocele in 4.0% (n = 4), aseptic meningitis in 2.0% (n = 2) and hydrocephalus in 1.0% (n = 1). Osseous decompression without duraplasty was performed in only four highly selected patients, not allowing a comparative analysis with duraplasty. Post-operative symptom improvement is reported for 67.3% of all patients and stabilization of symptoms in 23.9%. Symptom improvement was significantly more frequent in the non-syringomyelia group (p = 0.03). Outcome seemed similarly good in the pediatric and the adult groups.


PFD performed with duraplasty is a safe procedure. The majority of patients do report symptom stabilization or improvement. Non-syringomyelia patients reported significantly more frequent improvement of clinical symptoms.


Chiari malformation type I Posterior fossa decompression Safety Clinical presentation 



Cerebrospinal fluid


External ventricular drain


Syringosubarachnoid shunt


Syringoperitoneal shunt


Ventriculoperitoneal shunt


Posterior fossa decompression


Urinary tract infection


Respiratory tract infection


Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest. There was no funding for this paper.

Ethical approval

All authors listed as co-authors have authorized to submit this manuscript via e-mail to the corresponding author. The work is an original report and we did not include data from other studies. It has not been published elsewhere; it is not under consideration in any other journal. All the tables are the authors’ work and are based on our own data.

Informed consent

This is a retrospective study and, therefore, the ethical board of our institution did not require an informed consent of the patients to perform this study.


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Copyright information

© Belgian Neurological Society 2019

Authors and Affiliations

  • J. De Vlieger
    • 1
    Email author
  • J. Dejaegher
    • 1
  • F. Van Calenbergh
    • 1
  1. 1.Department of NeurosurgeryUniversity HospitalsLeuvenBelgium

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