Aneurysm Remnants after Flow Diversion: Clinical and Angiographic Outcomes.

BACKGROUND AND PURPOSE: Flow diversion is an established method to treat complex intracranial aneurysms. The natural history of flow-diversion treatment failure resulting in aneurysm remnants is not well-defined. We aimed to delineate the clinical and angiographic features of this entity. MATERIALS AND METHODS: Review of a prospectively maintained Pipeline Embolization Device data base from inception to October 2017 was performed for aneurysms that demonstrated residual filling on follow-up imaging. Procedural and follow-up clinical details were recorded. Independent, blinded, angiographic assessment of occlusion was performed on the basis of the O'Kelly-Marotta scale. Aggregated outcomes were analyzed using the Fisher exact and Mann-Whitney U tests for categoric and continuous variables, respectively (statistical significance, α = .05). RESULTS: During the study period, 283 sequential patients were treated; 87% (246/283) were women. The median patient age was 55 years (interquartile range, 47-65 years). Six-month follow-up imaging was available in 83.7% (237/283) of patients, which showed 62.4% (148/237) complete occlusion (class D, O'Kelly-Marotta grading scale). Adjunctive coiling (P = .06), on-label Pipeline Embolization Device use (P = .04), and multiple device constructs (P = .02) had higher rates of complete occlusion at 6 months. Aneurysm remnants were identified in 25 cases on long-term follow-up imaging (median, 16 months; interquartile range, 12-24 months). No patient with an aneurysm remnant after flow diversion presented with delayed rupture or other clinical sequelae, with a median clinical follow-up of 31 months (interquartile range, 23-33 months). CONCLUSIONS: Aneurysm remnants after flow diversion are infrequent with minimal clinical impact. When appropriate, the presence of overlapping devices and possibly adjunctive coiling may result in higher rates of complete occlusion.

Angiographic and clinical outcomes in 200 consecutive patients with cerebral aneurysm treated with hydrogel-coated coils.

BACKGROUND AND PURPOSE: Denser coil packing in intracranial aneurysms is believed to result in lower recanalization rates. Hydrogel-coated expandable coils (HydroCoil) improve volumetric packing of aneurysms in animal models and clinical studies, but data from large clinical series are limited. The objective of this retrospective analysis was to analyze immediate and follow-up angiographic results as well as complications in a large consecutive series of patients treated with HydroCoils at a single institution. MATERIALS AND METHODS: Retrospective analysis was performed of periprocedural complications, immediate and follow-up angiograms, and retreatments of the first 200 consecutive intracranial aneurysms treated at Emory University Hospital. RESULTS: One hundred eighty-seven patients with 200 intracranial aneurysms were treated with HydroCoils during a 3-year period. Immediate angiograms showed complete aneurysmal obliteration in 58.4% of small aneurysms and 42.7% of large aneurysms. Periprocedural complications included early rebleeding and thromboembolic events resulting in permanent neurologic morbidity and mortality in 6% of cases. Follow-up angiography during an average of 16.3 months demonstrated recanalization in 17.7% of small aneurysms and 28.6% of large aneurysms, requiring retreatment in 6.3% and 19.0% of cases, respectively. During the same time period, there was delayed angiographic improvement in aneurysm obliteration in 26.6% of small aneurysms and 26.2% of large aneurysms. CONCLUSIONS: First-generation HydroCoil treatment of intracranial aneurysms has a favorable rate of recanalization compared with most large series of pure platinum coils with similar complication rates.

Microscopic computed tomography imaging of the cerebral circulation in mice: feasibility and pitfalls.

This study evaluates the utility and practical limitations of microcomputerized X-ray tomography (CT) as a research tool for examination of the cerebral circulation in mice. Six micro CT angiograms of the circle of Willis (COW) from six mice were obtained by scanning whole head and brain specimen perfused with a radio-opaque silicone contrast agent. Two-dimensional volume rendered images were postprocessed from three-dimensional image datasets using a partially automated high-throughput model that generated 10 surface projections for each specimen. The image processing model employed a straightforward global thresholding and computerized component labeling software algorithm. Postprocessed images were analyzed and results correlated with microdissection. Micro CT demonstration of COW vessels and their branch anatomy was assessed. 71% of COW vessels were completely demonstrated, 26% were partially demonstrated, and 3% were not demonstrated. All cases of nondemonstration and most cases of partial demonstration resulted from scan coverage or postprocessing clip error. Thresholding effect caused pseudostenosis of 8% of COW vessels and accounted for a minority of partial demonstration cases. No imaging artifacts were caused by contrast extravasation or ineffective contrast perfusion. Volume averaging caused minor angioarchitectural distortion of 58% of COW vessels. Ninety-five percent of COW > or =50 microm and 52% of COW vessels <50 microm were correctly identified by micro CT. Micro CT of the murine COW using a high-throughput image processing model is feasible. Angioarchitectural distortion due to volume averaging and thresholding effect can occur and pathological findings should be confirmed.

Microsurgical anatomy of the artery of Adamkiewicz and its segmental artery.

OBJECT: The blood supply of the lower spinal cord is heavily dependent on the artery of Adamkiewicz, which characteristically originates from one of the thoracolumbar segmental arteries. The aforementioned artery is of enormous clinical, surgical, and radiological importance, and the goal of this study was to elucidate the course and branches of the segmental artery that gives rise to this important vessel. METHODS: In this cadaveric, microsurgical anatomical study, the authors investigate and describe the course and branches of the artery of Adamkiewicz and the segmental branch from which it ultimately originates. A review of the literature is provided. CONCLUSIONS: By documenting the microsurgical anatomy of these important vessels, this study facilitates an understanding of the anatomy that will aid in treatment planning for surgery of various lesions in this area.

Histologic and morphologic comparison of experimental aneurysms with human intracranial aneurysms.

PURPOSE: Vein pouch aneurysms are the most commonly created experimental lesions in neuroendovascular research. We sought to determine whether an experimental aneurysm that is derived from a pancreatic elastase-digested arterial sac (EDASA) models the histology and morphology of human cerebral aneurysms more accurately than the vein pouch aneurysm does. METHODS: EDASAs were created in the common carotid arteries of four rabbits, and vein pouch aneurysms were created in the common carotid arteries of four pigs. Five recently ruptured human cerebral aneurysms were obtained at autopsy. Identical histologic preparations were made for all specimens, and a vascular pathologist performed blinded histologic analyses. Morphologic dimensions were measured with a micrometer at 40-fold magnification. RESULTS: In each human cerebral aneurysm, there was complete absence of internal elastic lamina and tunica media, and none showed evidence of mural inflammation or neointimal proliferation. Average wall thickness was 51 microm. All vein pouch aneurysms had a well-developed internal elastic lamina and tunica media, and all exhibited profound inflammation and neointimal proliferation. Average wall thickness was 290 microm. EDASAs were devoid of internal elastic lamina, their tunica medias were mildly atrophic, and the sac walls contained only mild inflammation and neointimal proliferation. Average wall thickness was 46 microm. CONCLUSIONS: EDASAs model the morphologic and histologic characteristics of human cerebral aneurysms more accurately than vein pouch aneurysms do.

Microsurgical anatomy of the dorsal cervical nerve roots and the cervical dorsal root ganglion/ventral root complexes.

BACKGROUND: It is known that a "dissociated motor loss" of the deltoid muscle can occur with disconcerting frequency after cervical spine surgery. The etiology of this entity is in question. We conducted an anatomic study to identify anatomic factors that might predispose C5 to injury. METHODS: We studied 128 dorsal cervical nerves and root ganglion/ventral root complexes in 10 adult cadavers. At each cervical level the following data were recorded: number of rootlets, range of width of rootlets, length of DREZ, cranial angles of the superior and inferior rootlets with the spinal cord, length of the superior and inferior rootlets, dimensions of the foramina, dimensions of the dorsal root, dimensions of the dorsal root ganglion (DRG)/ventral root (VR) complex, and the blood supply to the DRG. The histology at the site of compression was also examined. Statistical analysis was conducted using the single factor-repeated measures analysis of variance. RESULTS: We found that, 1) the C5 superior dorsal rootlets angle less inferiorly from the cervical cord than the other dorsal cervical roots (p=0.001), 2) the majority of the DRG/VR complexes from C3 to C6 were compressed by the vertebral artery (73%), 3) the C5 DRG/VR complex was compressed to the greatest extent (77.6%, p=0.3519), and 4) the ganglionic artery was more frequent at C4, C5, and C6. CONCLUSION: To our knowledge, the second finding has not been reported previously. The first and third findings may help explain why C5 is more vulnerable to injury.

Surgical treatment of paraclinoid and ophthalmic aneurysms.

Paraclinoid aneurysms include those arising from the ophthalmic segment and from the distal cavernous carotid artery or clinoid segment. Three aneurysm variants originate from the ophthalmic segment: ophthalmic artery, superior hypophyseal artery, and dorsal types. Clinoidal segment aneurysms arise from the carotid artery in the interval between the carotid oculomotor membrane proximally and the dural ring distally, and include anterior-lateral and medial variants. With proper exposure and a firm understanding of the parasellar osseous, dural, and vascular anatomy, most paraclinoid aneurysms are occluded with low risk to the brain or visual apparatus.

Efficacy and biocompatibility of a photopolymerized, synthetic, absorbable hydrogel as a dural sealant in a canine craniotomy model.

OBJECT: A canine craniotomy model was used to evaluate the dural sealing efficacy and biocompatibility of a novel, synthetic, bioresorbable hydrogel. METHODS: Bilateral craniotomies were performed in 24 dogs assigned to six survival periods. In each animal a parasagittal durotomy was created and then repaired. At the treatment sites the hydrogel sealant was applied over the dural repair and photopolymerized. The repair was tested for leaks to 20 cm H2O by using a Valsalva maneuver. At the control sites the incisions were sutured and tested for leaks only. After uneventful survival periods, the leak test was repeated in three of the four animals in each group. Bone-dura adhesion was evaluated, after which the dura and underlying brain were removed, fixed, and examined histologically. En bloc histological investigation was performed on a specimen obtained from the fourth animal in each group. Over a 56-day period, 18 treated sites were tested for leaks. A leak was detected at a site remote from that of the repair in one animal; this was excluded from analysis. Thus 17 of 17 treated sites remained free of leaks. On the control side of one animal, there was a leak from a new dural tear at the cranial end of the durotomy, which occurred when the bone flap was removed. This site was also excluded from analysis. Eleven of 17 leak-tested control sites remained free of leaks over the study period. Bone-dura adhesions occurred in 15 of 19 control sites and had a mean adhesion score of 1.37 (range 0-4), whereas adhesions occurred in 10 of 19 treated sites with a mean adhesion score of 0.84 (range 0-3). No cortical reaction was noted. CONCLUSIONS: This novel hydrogel sealant is efficacious in sealing dural repair sites measuring up to 2 mm. Healing of the underlying dura is not compromised and exposed cortical tissue is not altered histologically.

Arterial saccular aneurysm model in the rabbit.

Saccular aneurysms arising from the common carotid artery in the neck at the origin of the internal carotid artery were created in male rabbits using the stump of a ligated external carotid artery. These stumps were intraluminally perfused with varying concentrations of porcine pancreatic elastase for 45 minutes via a microcatheter introduced into the femoral artery. The aneurysms were allowed to mature for 2 to 12 weeks. Gross examination and histologic studies confirmed the presence of an aneurysm in all 15 experiments. Ninety-two percent (12 of 13) of the aneurysms studied by postoperative angiography were shown to be angiographically patent: 40% of all aneurysms were noted to be patent at harvest; and the remainder showed evidence of intraluminal thrombus. On histologic examination, all aneurysms showed complete loss of elastic lamina without evidence of fibrosis or scarring.

Use of an instrument-holding clip for deeply recessed anastomoses of the rectum and esophagus.

Posterior layer closure of deeply located anastomoses including those performed in the course of low anterior rectal resection, total gastrectomy, and esophagogastrectomy, are often difficult. Usually five to six seromuscular or through-and-through posterior wall sutures are inserted sequentially and the loop or cut end of bowel is advanced over these parallel sutures. The sutures are then tied down. Entanglement of these sutures in a deep surgical field with limited access can lead to tears in the bowel wall. In addition, uneven and nonsequential tying of these sutures may compromise the anastomosis itself. We have described here how manual anastomosis in deep, hard to reach surgical fields can be better accomplished with the use of an instrument-holding clip. Use of the described instrument-holding clip, to clearly delineate and anchor each suture in sequence, eliminates these problems. An easily available device, it can save operative time, facilitate a more even anastomosis, and decrease the chance of bowel wall tearing, thus enhancing the security of the anastomosis.

Dental chair apoplexy.

We have reported two cases of intracranial bleeding shortly after a dental procedure. We argue that administration of hypochlorite in gum debridement, application of dental cement, or mechanical stimulation of the alveolar branches of the trigeminal nerve at the pulp may not only result in acute systemic hypertension, but also in the release of vasodilatory neurotransmitters. The combination of a local increase in intracerebral blood flow and simultaneously developing systemic hypertension in an occasional patient may lead to intracranial hemorrhage.