Taryn McFadden Bragg and Edward A. M. Duckworth
Numerous nuanced approaches have been used to access posterior inferior cerebellar artery (PICA) aneurysms for microsurgical clipping. The authors report the case of a patient with a right vertebral artery (VA)–PICA aneurysm that was reached via a contralateral far-lateral approach. The wide-necked saccular/fusiform aneurysm arose from the lateral aspect of the right V4 segment just proximal to the PICA origin, anterior to the jugular tubercle at the level of the hypoglossal canal. Computed tomography angiograms demonstrated the size and configuration of the aneurysm, and 3D reconstructions revealed the tortuosity of the right VA, defining its location just left of the midline adjacent to the lower clivus.
A contralateral far-lateral approach to VA–PICA aneurysms should be considered when aneurysms cross the midline. Computed tomography angiography with volume rendering and interactive software capabilities can help identify the relationship of such an aneurysm to an individual's particular skull base osseous anatomy and is paramount in selecting the optimal microsurgical approach.
Visish M. Srinivasan, Peter Kan and Edward A. M. Duckworth
Jonathan N. Sellin, Baraa Al-Hafez and Edward A. M. Duckworth
The authors report a case of trigeminal hypesthesia caused by compression of the spinal cord by a C-2 segmental-type vertebral artery (VA) that was successfully treated with microvascular decompression. Aberrant intradural VA loops have been reported as causes of cervical myelopathy, some of which improved with microvascular decompression. A 52-year-old man presented with progressive complaints of headache, dizziness, left facial numbness, and left upper-extremity paresthesia that worsened when turning his head to the right. Magnetic resonance imaging of the cervical spine showed the left VA passing intradurally between the axis and atlas, foregoing the C-1 foramen transversarium, and impinging on the spinal cord. The patient underwent left C-1 and C-2 hemilaminectomies followed by microvascular decompression of an aberrant VA loop compressing the spinal cord. The patient subsequently reported complete resolution of symptoms.
Visish M. Srinivasan, Gouthami Chintalapani, Edward A. M. Duckworth and Peter Kan
The evaluation of the venous neurovasculature, especially the dural venous sinuses, is most often performed using MR or CT venography. For further assessment, diagnostic cerebral angiography may be performed. Three-dimensional rotational angiography (3D-RA) can be applied to the venous system, producing 3D rotational venography (3D-RV) and cross-sectional reconstructions, which function as an adjunct to traditional 2D digital subtraction angiography.
After querying the database of Baylor St. Luke’s Medical Center in Houston, Texas, the authors reviewed the radiological and clinical data of patients who underwent 3D-RV. This modality was performed based on standard techniques for 3D-RA, with the catheter placed in the internal carotid artery and a longer x-ray delay calculated based on time difference between the early arterial phase and the venous phase.
Of the 12 cases reviewed, 5 patients had neoplasms invading a venous sinus, 4 patients with idiopathic intracranial hypertension required evaluation of venous sinus stenosis, 2 patients had venous diverticula, and 1 patient had a posterior fossa arachnoid cyst. The x-ray delay ranged from 7 to 10 seconds. The 3D-RV was used both for diagnosis and in treatment planning.
Three-dimensional RV and associated cross-sectional reconstructions can be used to assess the cerebral venous vasculature in a manner distinct from established modalities. Three-dimensional RV can be performed with relative ease on widely available biplane equipment, and data can be processed using standard software packages. The authors present the protocol and technique used along with potential applications to venous sinus stenosis, venous diverticula, and tumors invading the venous sinuses.
O. Howard Reichman, Edward A. M. Duckworth, Douglas E. Anderson and Thomas C. Origitano
✓The conventional wisdom resulting from the international, multicenter, trial of extracranial–intracranial bypass surgery is that this procedure offers no benefit. Because of the complex and unique circumstances of some, clinical experience and judgment must sometimes overrule some statistical conclusions.
Sabih T. Effendi, Vikas Y. Rao, Eric N. Momin, Jovany Cruz-Navarro and Edward A. M. Duckworth
The transbasal approach (TBA) is an anterior skull base approach, which provides access to the anterior skull base, sellar-suprasellar region, and clivus. The TBA typically involves a bifrontal craniotomy with orbital bar and/or nasal bone osteotomies performed in 2 separate steps. The authors explored the feasibility of routinely performing this approach in 1 piece with a quantitative cadaveric anatomical study, and present an operative case example of their approach.
Seven latex-injected cadaveric heads underwent a 1-piece TBA, followed by additional bone removal typical for a traditional 2-piece approach. Six surgical angles relative to the pituitary stalk, as well as the surface area of the orbital roof osteotomy, were measured before and after additional bone removal. The vertical angle from the frontonasal suture to the foramen cecum was measured in all specimens. In addition to an anatomical study, the authors have used this technique in the operating room, and present an illustrative case of resection of an anterior skull base meningioma.
Morphometric results were as follows: the vertical angle from the frontonasal suture to the foramen cecum ranged from 17.4° to 29.7° (mean 23.8° ± 4.8°) superiorly. Of the 6 surgical angle measures, only the middle horizontal angle was increased in the 2-piece versus the 1-piece approach (mean 43.4° ± 4.6° vs 43.0° ± 4.3°, respectively; p = 0.049), with a mean increase of 0.4°. The surface area of the orbital osteotomy was increased in the 2-piece versus the 1-piece approach (mean 2467 mm2 ± 360 mm2 vs 2045 mm2 ± 352 mm2, respectively; p < 0.001). The patient in the illustrative clinical case had a good outcome, both clinically and cosmetically.
The 1-piece TBA provides an alternative to the traditional 2-piece approach. It allows easier reconstruction, potentially decreased operative time, and improved cosmesis. While more of the orbital roof can be removed with the 2-piece approach, this additional bone removal offers only a small increase in 1 of 6 surgical angles that were measured.
Peter Kan, Visish M. Srinivasan, Nnenna Mbabuike, Rabih G. Tawk, Vin Shen Ban, Babu G. Welch, Maxim Mokin, Bartley D. Mitchell, Ajit Puri, Mandy J. Binning and Edward Duckworth
The Pipeline Embolization Device (PED) was approved for the treatment of intracranial aneurysms from the petrous to the superior hypophyseal segment of the internal carotid artery. However, since its approval, its use for treatment of intracranial aneurysms in other locations and non-sidewall aneurysms has grown tremendously. The authors report on a cohort of 15 patients with 16 cerebral aneurysms that incorporated an end vessel with no significant distal collaterals, which were treated with the PED. The cohort includes 7 posterior communicating artery aneurysms, 5 ophthalmic artery aneurysms, 1 superior cerebellar artery aneurysm, 1 anterior inferior cerebellar artery aneurysm, and 2 middle cerebral artery aneurysms. None of the aneurysms achieved significant occlusion at the last follow-up evaluation (mean 24 months). Based on these observations, the authors do not recommend the use of flow diverters for the treatment of this subset of cerebral aneurysms.