Objectives Two main surgical approaches for symptomatic Chiari type I malformation (CM-I) patients are posterior fossa decompression (PFD) involving craniectomy alone, and posterior fossa decompression with duraplasty (PFDD). The aim of this review was to outline the indications, advantages and disadvantages of each surgical approach, with guidance regarding surgical decisions.

Methods We reviewed pertinent articles. Data on the clinical improvement, radiological improvement, complications and reoperations were compared.

Results Seventeen articles containing data on 3713 paediatric and adult participants met the inclusion criteria. PFDD was associated with more favourable clinical improvement in CM-I patients with syringomyelia (RR 1.59, 95% Cl, 1.09 to 2.31; p<0.05), but had a higher complication rate (RR 3.34, 95% Cl, 1.66 to 6.73; p<0.05) when compared with PFD. Regarding radiological improvement and reoperation rates, no significant differences were observed between the two surgical approaches.

Conclusions Both PFD and PFDD are effective and safe surgical strategies for symptomatic CM-I associated with posterior fossa volume mismatch, in the absence of hydrocephalus and craniocervical region instability. Bony PFD has a lower complication rate and seems to be good option when carried out in those without major tonsillar impaction and in the absence of a syrinx. However, these patients should be adequately counseled regarding the requirement for possible further intra-dural decompression.