Minimally Invasive Non-Expansile Tubular Extradural Posterior Fossa Decompression (MINTED Technique) for the management of Chiari I.5 Malformation: Historical Overview of Surgical Techniques, Technical Note, Proof of Concept, Illustrative Case and Ca

BACKGROUND: Chiari's Malformation surgical treatment has significantly changed since the "classical" technique description by Gardner (1950). It is probably the most commonly performed approach, even when multiple techniques are available because no substantial changes nor any clear surgical objectives have been made. OBJECTIVE: To demonstrate a new cutting-edge surgical technique mastering the advantage of each surgical procedure ever described in the history of Chiari's Malformation establishing three critical points in surgical technique: clear patient-specific surgical goals, dynamic posterior fossa reconstruction, and extradural occipitoatlantal dense-adhesions release. METHODS: A comprehensive review of historically described approaches, proof of concept of surgical technique in sim-station, technical note, and case series of four patients with Chiari I.5 Malformation treated by Minimally Invasive Non-expansile Tubular Extradural Decompression of the Posterior Fossa (MINTED Technique). This observational report is following the STROBE Guidelines. RESULTS: Historically comprehensive review includes 41 papers from which new surgical goals were defined. We demonstrate our experience with full pre and postoperative records and images in four patients with Chiari 1.5 malformation. Patients presented with chronic valsalva-related symptoms associated with brainstem down-displacement on MRI with symptoms resolution and no neck disability from day zero after surgery up to 24 months follow-up. CONCLUSIONS: We demonstrate the feasibility of performing a posterior fossa decompression with the MINTED technique for Chiari 1.5 Malformation. This technique is the first full non-expansile tubular approach ever described. We redefined new and reproducible patient-specific surgical goals. This extradural technique achieves a dynamic posterior fossa reconstruction while preserving the practical midline approach familiar to every neurosurgeon worldwide. Chiari I and I.5 Malformation are best suited to benefit from the MINTED technique. Further research with randomized clinical trials will warrant its widespread use.