Minimally Invasive Posterior Fossa Tubular Decompression for the Management of a Chiari 1.5 Malformation: Technical Note, Proof of Concept and Illustrative Case

Presented at SMISS Annual Forum 2018
By J. Romero-Rangel
With Richard Fessler MD, PhD,

Disclosures: J. Romero-Rangel None Richard Fessler MD, PhD B; Benvenue Medical.,

Introduction:

Neurosurgical techniques have evolved from the classical premise of “do anything needed to preserve neurological function” to a trending minimally invasive concept focusing on preserving neurological function while reducing bone and soft-tissue trauma the most, to improve quality of life. Chiari Malformation is a pathology which anatomically and physiologically reunites two great neurosurgical fields: brain and Spine; and as such, it´s management requires mastering both surgical techniques.

Aims/Objectives:

The present work demonstrates a proof-of-concept of a surgical technique not ever described before, mixing a posterior cervical tubular approach with a posterior fossa decompression to the resolution of a complex craniocervical malformation with severe neurological disfunction such as Chiari 1.5.

Methods:

We did perform a Systematic Revision of Literature with the PRISMA criteria in order to review the stat-of-the art in Chiari Malformation Management and its relation to tubular approaches searching whole OVID, EBSCO, and PubMED data, finding no article referring to a posterior cervical tubular approach for its resolution. We did review the indications and treatment goals of the posterior fossa decompression and concluded that based on scientific evidence, resecting the posterior Arc of C1 and performing a 2-over-2 cm craniotomy are the optimal surgical targets (in the absence of accompanying syringomyelia, where duroplasty should be performed). We proceed to perform a simulation of the surgical procedure in a dummy-spine model, finding no major drawback to its implementation.

Results:

The surgical technique implies the use of a classical midline corridor across the posterior raphe with the benefit of reducing surgical exposure to a 3.5 cm incision while limiting muscle dissection to the 2-over-2 cm area where decompression is performed at the occipital base and the posterior arc of C1, respecting muscle inserts on nuchal lines and C2 as opposed to an open posterior fossa decompression. We do expose an illustrative-case with full pre and postoperative Images and video of a 31-year-old male with Chiari 1.5 malformation without syringomyelia, who presented with Valsalva-related syncope associated with bulbar compression by descended cerebellar tonsils, with full symptom resolution and no neck disability from day one after surgery up to present follow-up.

Conclusions:

We demonstrate the feasibility to perform a Posterior Fossa Decompression with a Minimally Invasive Posterior Cervical Tubular Approach in the setting of a Chiari 1.5 Malformation without syringomyelia, achieving optimal treatment goals and similar early outcomes to the open technique while reducing symptoms and potential complications related to soft-tissue trauma.