A less invasive suboccipital decompression-cranioplasty for Chiari type I malformation: Is it beneficial?

This was a retrospective study of 10 Chiari Malformation type I patients who were treated by the author since 2010–2016. This study aims to elucidate the benefit of modified foramen magnum decompression by preserving the bone as propose upside down-inside out (UDIO). The principle of handling is posterior fossa decompression (suboccipital decompression), as an established procedure, and ensures craniocaudal cerebrospinal fluid flow. Many complications such as cerebrospinal fluid leak, pseudomeningocele, dural adhesion, herniation of cerebellar tissue and cerebellar sag after foramen magnum decompression and duraplasty have been reported. The author wanted to know if the suboccipital decompression with additional cranioplasty, by reinstalling the suboccipital bone upside down-inside out (UDIO), is beneficial in this malformation treatment? There were 10 patients in this report, consisting of 7 females and 3 males. All patients were decompressed using the UDIO technique and duraplasty. All patients improved and, 1 patient needed a syringosubarachnoid shunt. There was no clinical deterioration, nor acute surgical complication and none suffered of pseudomeningocele and cerebellar sag, in an at least 12-months period of observation (range 12 months to 67 months). This small study suggests that the UDIO technique is safe, less invasive, beneficial and may be used as an option for Chiari type I malformation. Keywords: Chiari type I, Suboccipital decompression, Upside down-inside out, Cranioplast