Chiari malformation type 1: are we doing less with more? Illustrative case

Abstract

BACKGROUNDClassic treatment of Chiari malformation type 1 consists of foramen magnum decompression. Selected patients may require occipitocervical fixation, transoral odontoidectomy, tonsillectomy, and so forth. Treatment standardization does not yet exist, and some patients risk being overtreated.OBSERVATIONSA 20-year-old man with headache and Chiari malformation type 1 underwent extradural bone decompression. One year later, he was managed with the extradural section of his filum terminale. Eighteen months later, the patient underwent monitoring of intracranial pressure, occipitocervical stabilization, transoral odontoidectomy, minimally invasive subpial tonsillectomy, and occipital cranioplasty. His headache never changed, and he progressively developed hemiparesis and swallowing and respiratory disturbances. Two years later, a new magnetic resonance imaging scan showed extended syringomyelia with scarce peritonsillar subarachnoid space. The umpteenth operation consisted of the removal of a constricting epidural scar, arachnoid dissection, total tonsillectomy, creation of a wide subarachnoid space, and dural sac augmentation. The patient’s initial postoperative course was smooth, and his headache improved. However, 8 days after surgery, the patient acutely presented with vegetative disturbances and died because of malignant brainstem edema of unknown origin.LESSONSThe story of this patient is not so uncommon. He underwent all the possible surgical treatments rather than a timely adequate osteodural decompression. Probably, he received less with more.

Reoperation in Chiari-1 Malformations

“…However, one week later, this patient complained of severe vegetative disturbances and ultimately died despite no new lesion being shown by repeated MRI. This patient has already been reported [4].…”

“…Such ectopic tonsils do not necessarily constitute pathology. The wide diffusion of magnetic resonance imaging (MRI) is now showing a very high number of wholly asymptomatic and not progressive CM-1s [1][2][3][4][5][6][7]. These incidentally found CM-1s pose a problem with differential diagnosis and proper treatment indications [4,6].…”

“…The wide diffusion of magnetic resonance imaging (MRI) is now showing a very high number of wholly asymptomatic and not progressive CM-1s [1][2][3][4][5][6][7]. These incidentally found CM-1s pose a problem with differential diagnosis and proper treatment indications [4,6]. There is general agreement that surgery should be reserved for symptomatic patients, but the correct assessment of preoperative symptoms may not be easy [2,[6][7][8].…”

“…It is supposed that symptoms and signs of CM-1 would depend on the ectopic tonsils hampering the free circulation of cerebrospinal fluid (CSF) between the cranial and spinal compartments [9]. The tonsils would isolate the perimedullary CSF space, which would become unable to dissipate the normal pressure increases that occur during exercise, Valsalva maneuvers, breathing, changes in head position and even systole [4,6,9]. This would create the conditions for the development of CM-1 symptoms and syrinx.…”

“…Foramen magnum decompression (FMD) usually consists of occipital craniectomy and C1 laminectomy, with or without dural opening, dural augmentation, Magendie exploration, or tonsillectomy. Patients with craniocervical joint malformations (CVJM) may need occipitocervical fixation, with or without transoral odontoidectomy [4,5]. Postoperative complications mainly consist of cerebrospinal fluid (CSF) leaks and pseudomeningocele (PSMC), and range from 0% to 23%, depending on the surgical technique [10][11][12][13].…”