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Luis M. Tumialán, C. Michael Cawley, and Daniel L. Barrow

✓ The authors report the case of a 53-year-old woman in whom a T1–T2 spinal arachnoid cyst with associated arachnoiditis developed, compressing the thoracic spinal cord 1 year after the patient had suffered a Hunt and Hess Grade IV subarachnoid hemorrhage (SAH). Development of spinal arachnoiditis with or without an arachnoid cyst is a rare complication of aneurysmal SAH. Risk factors may include posterior circulation aneurysms, the extent and severity of the hemorrhage, and the need for cerebrospinal fluid diversion. Surgical drainage, shunt placement, or cyst excision, when possible, is the mainstay of treatment.

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Gordon Tang, C. Michael Cawley, Jacques E. Dion, and Daniel L. Barrow

Object. Indications for intraoperative angiography during aneurysm surgery remain unclear. To define its use, the authors report the results of a prospective study in which this modality was used in all patients undergoing surgery for intracranial aneurysms.

Methods. Intraoperative angiography was performed prospectively in the surgical treatment of 517 consecutive aneurysms regardless of the lesion's location, size, or complexity. In 64 (12.4%) of 517 aneurysms intraoperative angiography findings prompted a change in surgical treatment. Residual aneurysm (47%) was the most frequent finding leading to clip revision. In 44% of cases, intraoperative angiography revealed vessel compromise. Surgery for aneurysms of the proximal internal carotid artery (ICA) was the most frequently altered, with lesions located at the superior hypophyseal artery (SHA) and clinoidal region having the highest revision rates, eight (40%) of 20 and eight (44%) of 18, respectively. Aneurysm size predicted the need for revision; giant aneurysms (> 24 mm) underwent revision in nine (29%) of 31 cases, whereas large aneurysms (15–24 mm) were revised in 12 (22%) of 54 cases. In a multivariate logistic regression model, factors related to increased revision rates included the SHA and clinoidal locations, as well as giant and large size. Ninety-five patients underwent both intraoperative and postoperative angiography. Five discrepancies were noted (95% accuracy); four were flow-related and one involved a previously unrecognized residual aneurysm. Complications attributable to intraoperative angiography occurred in 0.4% of cases.

Conclusions. Proximal ICA location and large aneurysm size significantly predicted revision of surgery following intraoperative angiography. Unexpected findings, even in less complex locations, are frequently identified on intraoperative angiography. Low complication rates, high accuracy, and the unexpected need for clip readjustments favor a more widespread use of intraoperative angiography.

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Cargill H. Alleyne Jr., C. Michael Cawley, George G. Shengelaia, and Daniel L. Barrow

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.

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Cargill H. Alleyne Jr., C. Michael Cawley, George G. Shengelaia, and Daniel L. Barrow

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.

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Jacob Cherian, Thomas P. Madaelil, Frank Tong, Brian M. Howard, C. Michael Cawley, and Jonathan A. Grossberg

The video highlights a challenging case of bilateral vertebral artery dissection presenting with subarachnoid hemorrhage. The patient was found to have a critical flow-limiting stenosis in his dominant right vertebral artery and a ruptured pseudoaneurysm in his left vertebral artery. A single-stage endovascular treatment with stent reconstruction of the right vertebral artery and coil embolization sacrifice of the left side was performed. The case highlights the rationale for treatment and potential alternative strategies.

The video can be found here: https://youtu.be/e0U_JE2jISw.

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Luis M. Tumialán, Y. Jonathan Zhang, C. Michael Cawley, Jacques E. Dion, Frank C. Tong, and Daniel L. Barrow

Object

The introduction of the Neuroform microstent has facilitated the embolization of complex cerebral aneurysms, which were previously not amenable to endovascular therapy. Typically, the use of this stent necessitates the administration of dual antiplatelet therapy to minimize thromboembolic complications. Such therapy may increase the risk of hemorrhage in patients who require concurrent external ventricular drainage and/or subsequent permanent cerebrospinal fluid diversion.

Methods

The authors' neurosurgical database was queried for all patients who underwent stent-assisted coil embolization for cerebral aneurysms and who required an external ventricular drain (EVD) or ventriculoperitoneal (VP) shunt placement for management of hydrocephalus.

Results

Thirty-seven patients underwent stent-assisted coil embolization for intracranial aneurysms at the authors' institution over a recent 2-year period. Seven of these patients required placement of an EVD and/or a VP shunt. Three of the 7 patients suffered an immediate intraventricular hemorrhage (IVH) associated with placement or manipulation of an EVD; 1 experienced a delayed intraparenchymal hemorrhage and an IVH; 1 suffered an aneurysmal rehemorrhage; and the last patient had a subdural hematoma (SDH) that resulted from placement of a VP shunt. This patient required drainage of the SDH and exchange of the valve.

Conclusions

The necessity of dual antiplatelet therapy in the use of stent-assisted coil embolization increases the risk of intracranial hemorrhage and possibly rebleeding from a ruptured aneurysm. This heightened risk must be recognized when contemplating the appropriate therapy for a cerebral aneurysm and when considering the placement or manipulation of a ventricular catheter in a patient receiving dual antiplatelet therapy. Further study of intracranial procedures in patients receiving dual antiplatelet therapy is indicated.

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Cargill H. Alleyne Jr., C. Michael Cawley, Daniel L. Barrow, Bradley C. Poff, Michelle D. Powell, Amarpreet S. Sawhney, and Dirck L. Dillehay

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.

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Aaron S. Dumont, Avery J. Evans, and Mary E. Jensen

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Roberto C. Heros

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Evan Joyce, Michael T. Bounajem, Jonathan Scoville, Ajith J. Thomas, Christopher S. Ogilvy, Howard A. Riina, Omar Tanweer, Elad I. Levy, Alejandro M. Spiotta, Bradley A. Gross, Brian T. Jankowitz, C. Michael Cawley, Alexander A. Khalessi, Aditya S. Pandey, Andrew J. Ringer, Ricardo Hanel, Rafael A. Ortiz, David Langer, Michael R. Levitt, Mandy Binning, Philipp Taussky, Peter Kan, and Ramesh Grandhi

OBJECTIVE

The incidence of already common chronic subdural hematomas (CSDHs) and other nonacute subdural hematomas (NASHs) in the elderly is expected to rise as the population ages over the coming decades. Surgical management is associated with recurrence and exposes elderly patients to perioperative and operative risks. Middle meningeal artery (MMA) embolization offers the potential for a minimally invasive, less morbid treatment in this age group. The clinical and radiographic outcomes after MMA embolization treatment for NASHs have not been adequately described in elderly patients. In this paper, the authors describe the clinical and radiographic outcomes after 151 cases of MMA embolization for NASHs among 121 elderly patients.

METHODS

In a retrospective review of a prospectively maintained database across 15 US academic centers, the authors identified patients aged ≥ 65 years who underwent MMA embolization for the treatment of NASHs between November 2017 and February 2020. Patient demographics, comorbidities, clinical and radiographic factors, treatment factors, and clinical outcomes were abstracted. Subgroup analysis was performed comparing elderly (age 65–79 years) and advanced elderly (age > 80 years) patients.

RESULTS

MMA embolization was successfully performed in 98% of NASHs (in 148 of 151 cases) in 121 patients. Seventy elderly patients underwent 87 embolization procedures, and 51 advanced elderly patients underwent 64 embolization procedures. Elderly and advanced elderly patients had similar rates of embolization for upfront (46% vs 61%), recurrent (39% vs 33%), and prophylactic (i.e., with concomitant surgical intervention; 15% vs 6%) NASH treatment. Transfemoral access was used in most patients, and the procedure time was approximately 1 hour in both groups. Particle embolization with supplemental coils was most common, used in 51% (44/87) and 44% (28/64) of attempts for the elderly and advanced elderly groups, respectively. NASH thickness decreased significantly from initial thickness to 6 weeks, with additional decrease in thickness observed in both groups at 90 days. At longest follow-up, the treated NASHs had stabilized or improved in 91% and 98% of the elderly and advanced elderly groups, respectively, with > 50% improvement seen in > 60% of patients for each group. Surgical rescue was necessary in 4.6% and 7.8% of cases, and the overall mortality was 8.6% and 3.9% for elderly and advanced elderly patients, respectively.

CONCLUSIONS

MMA embolization can be used safely and effectively as an alternative or adjunctive minimally invasive treatment for NASHs in elderly and advanced elderly patients.