Multimodal evaluation of CSF dynamics following extradural decompression for Chiari malformation Type I

Abstract

<jats:sec> <jats:title>OBJECT</jats:title> <jats:p>Extradural decompression is a minimally invasive technique for treating Chiari malformation Type I (CM-I) that avoids the complications of dural opening. While there is no agreement on which surgical method is optimal, mounting evidence demonstrates that extradural decompression effectively treats clinical symptoms, with a minimal reoperation rate. Neurological symptoms such as headache may be related to obstructed flow of CSF, and one aspect of successful extradural decompression is improved CSF dynamics. In this series, the authors report on their use of phase-contrast cine flow MRI to assess CSF flow as well as satisfactory decompression.</jats:p></jats:sec> <jats:sec> <jats:title>METHODS</jats:title> <jats:p>The authors describe their first surgical series of 18 patients with CM-I undergoing extradural decompression and correlate clinical improvement with radiological changes. Patients were categorized as having complete, partial, or no resolution of their symptoms. Posterior fossa area, cisterna magna area, and tonsillar herniation were assessed on T2-weighted MRI, whereas improvement of CSF flow was evaluated with phase-contrast cine flow MRI. All patients received standard pre- and postoperative MRI studies; 8 (44.4%) patients had pre- and postoperative phase-contrast cine, while the rest underwent cine studies only postoperatively.</jats:p></jats:sec> <jats:sec> <jats:title>RESULTS</jats:title> <jats:p>All 18 patients presented with symptomatic CM-I, with imaging studies demonstrating tonsillar herniation ≥ 5 mm, and 2 patients had associated syringomelia. All patients underwent suboccipital decompression and C-1 laminectomy with splitting of the dura. Patients with complete resolution of their symptoms had a greater relative increase in cisterna magna area compared with those with only partial improvement (p = 0.022). In addition, in those with complete improvement the preoperative cisterna magna area was smaller than in those who had either partial (0.020) or no (0.025) improvement. Ten (91%) of the 11 patients with improved flow also had improvement in their symptoms. There was 1 postoperative complication of dysphagia and dysphonia. None of the patients have required a second operation.</jats:p></jats:sec> <jats:sec> <jats:title>CONCLUSIONS</jats:title> <jats:p>Extradural decompression has the potential to be the first-line treatment for CM-I but has been lacking an objective measure by which to assess surgical success as well as the need for reoperation. An increase in the CSF spaces and improved CSF dynamics may be associated with resolution of clinical symptoms. Including cine imaging as part of routine pre- and postoperative evaluation can help identify which patients are most likely to benefit from surgery.</jats:p></jats:sec>

“Stealth cranioplasty:” A novel endeavor for symptomatic adult Chiari I patients with syringomyelia: Technical note, appraisal, and philosophical considerations

“…[ 20 21 22 23 24 ] Definite criteria and indications of surgery for CMI remain undefined, and still, there is no single definitive treatment protocol that is set unanimously. [ 21 25 26 27 28 ] However, almost all surgical approaches in the past and the present use have one thing in common - a suboccipital craniectomy with removal of posterior arch of C1 though there are controversies regarding the extent of it and additional measures taken along with. Management of the dura includes leaving the dura intact with removal of the constricting band only,[ 18 ] dural scoring,[ 29 30 ] resecting the outer layer of the dura,[ 24 27 31 32 ] opening the dura and leaving it open,[ 33 34 35 ] and performing a duraplasty.…”

“…[ 21 25 26 27 28 ] However, almost all surgical approaches in the past and the present use have one thing in common - a suboccipital craniectomy with removal of posterior arch of C1 though there are controversies regarding the extent of it and additional measures taken along with. Management of the dura includes leaving the dura intact with removal of the constricting band only,[ 18 ] dural scoring,[ 29 30 ] resecting the outer layer of the dura,[ 24 27 31 32 ] opening the dura and leaving it open,[ 33 34 35 ] and performing a duraplasty. [ 8 11 18 24 31 36 37 38 39 40 ] The arachnoid manipulation similarly varies from leaving it intact,[ 18 31 41 ] to opening and resecting it.…”

Role of Cranioplasty in Management of Chiari Malformation

“…However, there are disagreements and wide range of variations regarding the extent of bone removal and different additional measures taken along with. For management of CM1, dura can be addressed in different ways like leaving the dura intact with removal of the constricting bands only [9], scoring of Role of Cranioplasty in Management of Chiari Malformation DOI: http://dx.doi.org /10.5772/intechopen.90055 the dura [10,11], resection of the outer layer of the dura [12][13][14], opening the dura and keeping it remain open [15][16][17], and performing duraplasty with different materials, both natural and artificial [13,[18][19][20][21][22][23][24]. The arachnoid manipulation equally differs from leaving it intact by doing an arachnoid preserving durotomy or arachnoid preserving duraplasty [9,[25][26][27], to opening and resecting it to remove adhesions [8,19,23,[28][29][30].…”

“Stealth Cranioplasty” for Adult Chiari Malformation Type 1: A Philosophical Journey of Innovation, Adaptation, and Evolution

“…Nevertheless, there are controversies concerning the extent of bone removal and additional measures taken along with it [86,87]. Management of the dura includes leaving the dura intact with removal of the constricting band only [88], dural scoring [89,90], resecting the outer layer of the dura [67,[91][92][93][94], opening the dura and leaving it open [95][96][97][98], and performing a duraplasty [38,43,67,88,91,94,[99][100][101][102][103][104]. The arachnoid manipulation similarly varies from leaving it intact [88,91,105] to opening and resecting it [96, 99-103, 106, 107].…”