Too Much of a Good Thing? A Governing Knowledge Commons Review of Abundance in Context.

The economics of abundance, along with the sociology of abundance, the law of abundance, and so forth, should be re-framed, linked, and situated in a common context for empirical rather than conceptual research. Abundance may seem to be a new, big thing, between anxiety over information overload, Big Data, and related technological disruptions. But scholars know that abundance is an ancient phenomenon, which only seemed to disappear as twentieth century social science focused on scarcity instead. Restoring the study of abundance, and figuring out how to solve the problems that abundance might create, means shedding disciplinary blinders and going back to basics. How does abundance, in various forms, create or alleviate social problems? We explain and illustrate how the Governing Knowledge Commons (GKC) framework provides a useful research tool to generate and test hypotheses about abundance in various economic, social, cultural, and legal settings.

Procedural complications in patients undergoing microsurgical treatment of unruptured intracranial aneurysms: a single-center experience with 1923 aneurysms.

BACKGROUND: With the growing use of endovascular therapy (EVT) to manage unruptured intracranial aneurysms (IAs), detailed information regarding periprocedural complication rates of microsurgical clipping and EVT becomes increasingly important in determining the optimal treatment for individual cases. We report the complication rates associated with open microsurgery in a large series of unruptured IAs and highlight the importance of maintaining surgical skill in the EVT era. METHODS: We reviewed all cases of unruptured IAs treated with open microsurgery by a single neurosurgeon between July 1997 and June 2019. We analyzed surgical complications, deaths, and patient-reported outcomes. RESULTS: A total of 1923 unruptured IAs in 1750 patients (mean age 44 [range: 6-84], 62.0% [1085/1750] female) were treated surgically during the study period. Of the aneurysms treated, 84.9% (1632/1923) were small, 11.1% (213/1923) were large, and 4.1% (78/1923) were giant. Aneurysm locations included the middle cerebral artery (44.2% [850/1923]), internal carotid artery (29.1% [560/1923]), anterior cerebral artery (21.0% [404/1923]), and vertebrobasilar system (5.7% [109/1923]). The overall mortality rate was 0.3% (5/1750). Surgical complications occurred in 7.4% (129/1750) of patients, but only 0.4% (7/1750) experienced permanent disability. The majority of patients were able to return to their preoperative lifestyles with no modifications (95.9% [1678/1750]). CONCLUSIONS: At a high-volume, multidisciplinary center, open microsurgery in carefully selected patients with unruptured IAs yields favorable clinical outcomes with low complication rates. The improvement of EVT techniques and the ability to refer cases for EVT when a high complication rate with open microsurgery was expected have contributed to an overall decrease in surgical complication rates. These results may serve as a useful point of reference for physicians involved in treatment decision-making for patients with unruptured IAs.

Traumatic epidural hematoma treated with endovascular coil embolization.

BACKGROUND: Traumatic cerebrovascular injury may result in epidural hematoma (EDH) from laceration of the middle meningeal artery (MMA), which is a potentially life-threatening emergency. Treatment ranges from surgical evacuation to conservative management based on a variety of clinical and imaging factors. CASE DESCRIPTION: A 14-year-old male presented to our institution after falling from his bicycle with traumatic subarachnoid hemorrhage and a right frontotemporal EDH. The patient did not meet criteria for surgical evacuation and endovascular embolization of the right MMA was performed. Rapid resolution of the EDH was observed. CONCLUSION: This case corroborates the sparse existing literature for the potential role of endovascular embolization to treat acute EDH in carefully selected patients who do not meet or have borderline indications for surgical management.

Microsurgical Treatment of Unruptured Anterior Communicating Artery Aneurysms: Approaches and Outcomes in a Large Contemporary Series and Review of the Literature.

BACKGROUND: With advances in endovascular techniques, the relative roles of microsurgery and endovascular therapy in the management of intracranial aneurysms have become less clear, and data regarding treatment-specific outcomes are increasingly important. OBJECTIVE: To describe our experience with microsurgery in a large series of unruptured anterior communicating artery aneurysms (ACOMMAAs) and detail our treatment decision-making process based on individual aneurysm morphology. METHODS: We retrospectively reviewed unruptured ACOMMAAs treated microsurgically at our center between 1997 and 2018, recording aneurysm size, surgical approach, occlusion rates, neurological outcomes, and complications. RESULTS: We treated 300 unruptured ACOMMAAs in 300 patients, mean age 49 yr, 180 (60.0%) female, including 245 (81.7%) small, 50 (16.7%) large, and 5 (1.7%) giant aneurysms. Most underwent a pterional approach (253, 84.3%), with orbitozygomatic or anterior interhemispheric approaches in 35 (11.7%) and 12 (4%), respectively. Greater than 95% occlusion was achieved in 284 (94.7%), 90% to 95% occlusion in 13 (4.3%), and 3 (1.0%) underwent wrapping. Serious complications occurred in 3 patients (1.0%) resulting in 2 deaths (0.7%), and minor complications in 12 (4.0%). At final follow-up, good neurological outcome was observed in 297 (99.0%) patients. CONCLUSION: Given clinical equipoise regarding optimal treatment of unruptured ACOMMAAs, this work provides a benchmark for achievable microsurgical outcomes. Future surgical/endovascular studies should separate results of ruptured and unruptured lesions and describe aneurysm morphology to allow for better comparison of outcomes between treatments. We suggest that open microsurgery represents an important option for select, morphologically complex ACOMMAAs, and that a multidisciplinary approach offers optimal patient outcomes.

Endovascular aspiration to treat acute ischemic stroke caused by embolic carcinoma.

Although cardiac myxomas have been known to cause acute ischemic stroke and other cerebrovascular complications, intracranial embolization of metastatic tumor fragments is rare. This is likely because venous emboli generally cause pulmonary embolism. Pulmonary vein metastases and patent foramen ovales have previously shown to propagate intracranial embolic carcinomas, but these events are very uncommon, and are not well characterized. We report a rare case of large-cell, high-grade neuroendocrine lung cancer embolus occluding the basilar artery, which likely detached into the bloodstream from the lung after intruding into a pulmonary vein. The embolus was treated with endovascular aspiration, and achieved modified Thrombolysis In Cerebral Infarction 2c revascularization. After initial neurological recovery, the patient suffered respiratory arrest and support was withdrawn 48 h later. We discuss the tumor characteristics and implications for treatment of acute ischemic stroke in patients with cancer diagnoses.

Cerebral revascularization for the management of complex intracranial aneurysms: a single-center experience.

OBJECTIVEBecause simple intracranial aneurysms (IAs) are increasingly treated endovascularly, neurovascular surgery has become focused on complex IAs that may require deconstructive aneurysm therapy with concomitant surgical bypass. The authors describe the decision-making process concerning cerebral revascularization and present outcomes that were achieved in a large case series of complex IAs managed with cerebral revascularization and parent artery occlusion.METHODSThe authors retrospectively reviewed the medical records, including neuroimaging studies, operative reports, and follow-up clinic notes, of all patients who were treated at the National Brain Aneurysm Center between July 1997 and June 2015 using cerebral revascularization as part of the management of an IA. They recorded the location, rupture status, and size of each IA, as well as neurological outcome using the modified Rankin Scale (mRS), aneurysm and bypass status at follow-up, and morbidity and mortality.RESULTSThe authors identified 126 patients who underwent revascularization surgery for 126 complex, atheromatous, calcified, or previously coiled aneurysms. Ninety-seven lesions (77.0%) were unruptured, and 99 (78.6%) were located in the anterior circulation. Aneurysm size was giant (≥ 25 mm) in 101 patients, large (10-24 mm) in 9, and small (≤ 9 mm) in 16 patients. Eighty-four low-flow bypasses were performed in 83 patients (65.9%). High-flow bypass was performed in 32 patients (25.4%). Eleven patients (8.7%) underwent in situ or intracranial-intracranial bypasses. Major morbidity (mRS score 4 or 5) occurred in 2 (2.4%) low-flow cases and 3 (9.1%) high-flow cases. Mortality occurred in 2 (2.4%) low-flow cases and 2 (6.1%) high-flow cases. At the 12-month follow-up, 83 (98.8%) low-flow and 30 (93.8%) high-flow bypasses were patent. Seventy-five patients (90.4%) undergoing low-flow and 28 (84.8%) high-flow bypasses had an mRS score ≤ 2. There were no statistically significant differences in patency rates or complications between low- and high-flow bypasses.CONCLUSIONSWhen treating challenging and complex IAs, incorporating revascularization strategies into the surgical repertoire may contribute to achieving favorable outcomes. In our series, low-flow bypass combined with isolated proximal or distal parent artery occlusion was associated with a low rate of ischemic complications while providing good long-term aneurysm control, potentially supporting its wider utilization in this setting. The authors suggest that consideration should be given to managing complex IAs at high-volume centers that offer a multidisciplinary team approach and the full spectrum of surgical and endovascular treatment options to optimize patient outcomes.

The POST trial: initial post-market experience of the Penumbra system: revascularization of large vessel occlusion in acute ischemic stroke in the United States and Europe.

BACKGROUND AND PURPOSE: The purpose of this study was to assess the initial post-market experience of the device and how it is compared with the Penumbra Pivotal trial used to support the 510k application. METHODS: A retrospective case review of 157 consecutive patients treated with the Penumbra system at seven international centers was performed. Primary endpoints were revascularization of the target vessel (TIMI score of 2 or 3), good functional outcome as defined by a modified Rankin scale (mRS) score of ≤2 and incidence of procedural serious adverse events. Results were compared with those of the Penumbra pivotal trial. RESULTS: A total of 157 vessels were treated. Mean baseline values at enrollment were: age 65 years, NIHSS score 16. After use of the Penumbra system, 87% of the treated vessels were revascularized to TIMI 2 (54%) or 3 (33%) as compared with 82% reported in the Pivotal trial. Nine procedural serious adverse events were reported in 157 patients (5.7%). All-cause mortality was 20% (32/157), and 41% had a mRS of ≤2 at 90-day follow-up as compared with only 25% in the Pivotal trial. Patients who were successfully revascularized by the Penumbra system had significantly better outcomes than those who were not. CONCLUSION: Initial post-market experience of the Penumbra system revealed that the revascularization rate and safety profile of the device are comparable to those reported in the Pivotal trial. However, the proportion of patients who had good functional outcome was higher than expected.

Microsurgical treatment of unruptured middle cerebral artery aneurysms: a large, contemporary experience.

OBJECTIVEAdvances in endovascular therapy for the treatment of middle cerebral artery (MCA) aneurysms have led to scrutiny of its benefits compared with microsurgical repair. To provide information regarding complication rates and outcomes, the authors reviewed the results of a large series of unruptured MCA aneurysms treated with open microsurgery.METHODSThe authors included all patients who underwent surgical repair of an unruptured MCA aneurysm between 1997 and 2015. All surgical procedures, including clipping, wrapping, bypass, and parent artery occlusion, were performed by a single neurosurgeon. Aneurysm occlusion was assessed using intraoperative digital subtraction angiography (DSA) or DSA and indocyanine green videoangiography in all cases. Postoperatively, all patients were monitored in a neurointensive care unit overnight. Clinical follow-up was scheduled for 2-4 weeks after surgery, and angiographic follow-up was performed in those patients with subtotally occluded aneurysms at 1, 2, and 5 years postoperation.RESULTSThe authors treated 750 unruptured MCA aneurysms in 716 patients: 649 (86.5%) aneurysms were small, 75 (10.0%) were large, and 26 (3.5%) were giant. Most aneurysms (n = 677, 90%) were treated by primary clip reconstruction. The surgical morbidity rate was 2.8%, and the mortality rate was 0%. Complete angiographic aneurysm occlusion was achieved in 92.0% of aneurysms. At final follow-up, 713 patients had a modified Rankin Scale (mRS) score of 0, 2 patients had an mRS score of 2 or 3, and 1 had an mRS score of 4.CONCLUSIONSIn high-volume centers, microsurgical management of MCA aneurysms can be performed with very low morbidity rates. Currently, microsurgical repair appears to be a highly effective method of treating MCA aneurysms.

The POST trial: initial post-market experience of the Penumbra system: revascularization of large vessel occlusion in acute ischemic stroke in the United States and Europe.

BACKGROUND AND PURPOSE: The purpose of this study was to assess the initial post-market experience of the device and how it is compared with the Penumbra Pivotal trial used to support the 510k application. METHODS: A retrospective case review of 157 consecutive patients treated with the Penumbra system at seven international centers was performed. Primary endpoints were revascularization of the target vessel (TIMI score of 2 or 3), good functional outcome as defined by a modified Rankin scale (mRS) score of ≤2 and incidence of procedural serious adverse events. Results were compared with those of the Penumbra pivotal trial. RESULTS: A total of 157 vessels were treated. Mean baseline values at enrollment were: age 65 years, NIHSS score 16. After use of the Penumbra system, 87% of the treated vessels were revascularized to TIMI 2 (54%) or 3 (33%) as compared with 82% reported in the Pivotal trial. Nine procedural serious adverse events were reported in 157 patients (5.7%). All-cause mortality was 20% (32/157), and 41% had a mRS of ≤2 at 90-day follow-up as compared with only 25% in the Pivotal trial. Patients who were successfully revascularized by the Penumbra system had significantly better outcomes than those who were not. CONCLUSION: Initial post-market experience of the Penumbra system revealed that the revascularization rate and safety profile of the device are comparable to those reported in the Pivotal trial. However, the proportion of patients who had good functional outcome was higher than expected.

Remote distal outflow occlusion: a novel treatment option for complex dissecting aneurysms of the posterior inferior cerebellar artery. Report of 3 cases.

The authors report a novel management option for patients with complex dissecting aneurysms of the posterior inferior cerebellar artery (PICA). The authors reviewed the medical records and neuroimaging studies of 3 patients who underwent a novel surgical treatment for complicated dissecting PICA aneurysms. The mean follow-up period was 1.1 years, and no patient was lost to follow-up. Two patients were in poor condition following an acute, severe subarachnoid hemorrhage, and 1 presented with headaches and a remote history of bleeding. All patients underwent surgical occlusion of the PICA beyond the tonsillar loop, distal to the aneurysmal segment. Intraoperative and delayed follow-up angiography demonstrated progressive diminution in size of the aneurysmal dilation but persistent filling of the proximal PICA segments supplying the brainstem. Outcome was good in all cases. This novel technique has been used successfully in 3 cases and, to the authors' knowledge, has not been reported previously.

Peripheral intracranial aneurysms: management challenges in 60 consecutive cases.

OBJECT: The authors report the management and outcomes of 55 patients with 60 intracranial aneurysms arising distal to the major branch points of the circle of Willis and vertebrobasilar system. METHODS: Between July 1997 and December 2006, the authors' neurovascular service treated 2021 intracranial aneurysms in 1850 patients. The database was reviewed retrospectively to identify peripherally located intracranial aneurysms. Aneurysms that were mycotic and aneurysms that were associated with either an arteriovenous malformation or an atrial myxoma were excluded from review. RESULTS: The authors encountered 60 peripheral intracranial aneurysms in 55 patients. There were 42 small, 7 large, and 11 giant lesions. Forty-one (68%) were unruptured, and 19 (32%) had bled. Fifty-three aneurysms were treated surgically by using direct clip reconstruction in 26, trapping or proximal occlusion with distal revascularization in 21, excision with end-to-end anastomosis in 3, and circumferential wrap/clip reconstruction in 3. Coils were used to treat 6 aneurysms, and 1 was treated by endovascular parent artery occlusion. Overall, 49 patients had good outcomes, 4 were left with new neurological deficits, and 2 died. CONCLUSIONS: Peripherally situated intracranial aneurysms are rare lesions that present unique management challenges. Despite the fact that in the authors' experience these lesions were rarely treatable with simple clipping of the aneurysm neck or endovascular coil occlusion, preservation of the parent artery was possible in most cases, and the majority of patients had a good outcome.

Dissecting aneurysms of the posterior inferior cerebellar artery: retrospective evaluation of management and extended follow-up review in 6 patients.

OBJECT: The authors report the management protocol and successful outcomes in 6 patients with dissecting aneurysms of the posterior inferior cerebellar artery (PICA). METHODS: Medical records and neuroimaging studies of 6 patients who underwent surgical treatment of dissecting PICA aneurysms were reviewed. The mean follow-up duration was 1.8 years. No patient was lost to follow-up review. RESULTS: Four patients presented with acute subarachnoid hemorrhage and 2 with PICA ischemia. All patients underwent surgery, which entailed proximal occlusion with distal revascularization in 3 cases and circumferential wrap/clip reconstruction in 3 cases. The revascularization techniques used were occipital artery-PICA bypass and PICA-PICA anastomosis. Delayed follow-up angiography was performed in all cases. In patients treated with proximal occlusion, delayed angiography showed minimal retrograde opacification of the dissected segments. The 3 patients treated with wrap/clip reconstruction showed unexpectedly significant normalization of their lesions on angiographic studies. Outcome was good in all cases. CONCLUSIONS: Dissecting PICA aneurysms are rare lesions with an apparent propensity for bleeding. Individualized management including distal revascularization with PICA sacrifice or circumferential wrap/clip reconstruction to reinforce the dissected segment produced good outcomes. Patients treated with aneurysm wrapping may show dramatic angiographic improvement of the dissected segment.

Microsurgical treatment of unruptured intracranial aneurysms. A consecutive surgical experience consisting of 450 aneurysms treated in the endovascular era.

BACKGROUND: With the progressive refinement of endovascular techniques, fewer IAs are being treated with open microsurgery. There is limited information regarding the impact of this trend on the ability of younger neurosurgeons to achieve proficiency in the surgical management of IAs. We describe a consecutive series of patients with unruptured IAs treated by a neurosurgeon initiating a dedicated cerebrovascular practice in the "endovascular era." METHODS: We retrospectively reviewed the records of all patients who had undergone surgical repair of a saccular IA by one neurosurgeon upon completion of neurosurgical training in July 1997 until April 2005. Patients with ruptured IAs were excluded from review. RESULTS: Of the 1450 patients with IAs treated during this period, 376 underwent microsurgical repair of 450 unruptured IAs. Microsurgical aneurysm neck clipping was possible in most cases, although distal revascularization with proximal occlusion was used in many of the more complicated aneurysms. Major complications occurred in 6 (1.60%) patients, and 1 (0.27%) patient died. At the time of 6-month follow-up, 4 (1.06%) patients were left with a new focal neurologic deficit related to surgery. CONCLUSIONS: Despite the growing role of endovascular therapy in the management of IAs, it is possible for young neurovascular surgeons to achieve acceptable results with open microsurgical treatment of IAs. The factors that were deemed important in achieving success in this series included a collaborative approach with endovascular colleagues, careful surgical judgment, continual reanalysis of personal results, and early support from experienced mentors.

The treatment of advanced sinonasal malignancies with pre-operative intra-arterial cisplatin and concurrent radiation.

INTRODUCTION: Malignancies of the nasal and paranasal sinuses are uncommon tumors, accounting for only 3% of all aerodigestive tract neoplasms. Despite advances in surgical techniques and continued evolution of adjuvant therapies, the 5-year mortality remains unusually high at greater than 50%. In 1996, we begin utilizing a novel strategy in the treatment of advanced sinonasal carcinomas. This consisted of neoadjuvant selective intra-arterial cisplatin with concurrent radiation therapy (acronym RADPLAT) followed by a conservative craniofacial resection. We now report our results for 11 patients treated with this regimen. METHODS: Between July 1996 and April 2003, 11 patients with advanced sinonasal malignancies underwent treatment utilizing the RADPLAT protocol followed by a planned surgical resection via a craniofacial approach. Patient charts, operative notes, follow-up clinic notes, and pre- and post-operative imaging studies were reviewed in detail for each subject. RESULTS: Histopathological analysis of the tumors revealed seven squamous cell carcinomas (64%), two adenocarcinomas (18%), one adenoid cystic carcinoma (9%), and one sinonasal undifferentiated carcinoma (9%). T4N0M0 disease was present in nine patients (81%), and two patients had T3N0M0 disease (19%). Survival was calculated using the Kaplan-Meier method with an overall survival of 81% at 5 years and a progression-free survival at 5 years of 67%. Mean follow-up is 57.2 months ranging from 12 to 95 months. CONCLUSIONS: The treatment of advanced sinonasal malignancies with pre-operative intra-arterial cisplatin and concurrent radiation results in a significant improvement in survival. This can be done safely with high response rates and excellent loco-regional control in T3 and T4 disease. Although are results are encouraging, there is a need for a cooperative, multi-institutional, prospective study.

Catheter tip granuloma associated with sacral region intrathecal drug administration.

Spinal cord compression from catheter tip granulomatous masses following intrathecal drug administration may produce devastating permanent neurologic deficits. Some authors have advocated intrathecal catheter placement below the conus medullaris to avoid the possibility of spinal cord involvement. Multiple cases of catheter tip granulomas in the thoracolumbar region have been reported. We present a unique case of a sacral region catheter tip inflammatory mass producing permanent neurologic deficits. A 71-year-old white male with a diagnosis of failed back surgery syndrome was referred to the senior author for evaluation. After more extensive conservative therapy, including spinal cord stimulation, failed to yield adequate pain relief, he was offered implantation of an intrathecal pump for opioid administration. Excellent pain relief was achieved in the postoperative period; however, three years after implantation, he presented with progressive saddle anesthesia and bowel/bladder incontinence. Magnetic resonance imaging demonstrated a space occupying lesion associated with the catheter tip. The patient underwent emergent second level complete sacral laminectomy with partial resection of an intradural extra-axial mass and removal of intrathecal catheter. At discharge, the patient had no restoration of neurologic function. Histologic examination of the mass confirmed a sterile inflammatory mass. It has been suggested that intrathecal catheters be placed below the conus medullaris to avoid the possibility of spinal cord involvement. We present an unusual case documenting devastating permanent neurologic deficits from a catheter tip granuloma in the sacral region.