Paul M. Foreman

Venous drainage of the spine and spinal cord: A comprehensive review of its history, embryology, anatomy, physiology, and pathology

Venous drainage of the spine and spinal cord is accomplished through a complex network of venous structures compartmentalized to intrinsic, extrinsic, and extradural systems. As the literature on this topic is scarce, the following review was performed to summarize the available literature into a single coherent format. The medical literature on the spinal venous system was reviewed using online sources as well as historical documents that were not available online in regard to history, embryology, anatomy, and physiology with a particular emphasis on the pathology affecting this system. The spinal venous system is complex and variable. Proper understanding of all aspects is critical for the management of the pathology that results from its failure. Clin. Anat. 28:75–87, 2015.

Pipeline Embolization Device for small paraophthalmic artery aneurysms with an emphasis on the anatomical relationship of ophthalmic artery origin and aneurysm

OBJECTIVE Contemporary treatment for paraophthalmic artery aneurysms includes flow diversion utilizing the Pipeline Embolization Device (PED). Little is known, however, about the potential implications of the anatomical relationship of the ophthalmic artery (OA) origin and aneurysm, especially in smaller aneurysms. METHODS Four major academic institutions in the United States provided data on small paraophthalmic aneurysms (≤ 7 mm) that were treated with PED between 2009 and 2015. The anatomical relationship of OA origin and aneurysm, radiographic outcomes of aneurysm occlusion, and patency of the OA were assessed using digital subtraction angiography. OA origin was classified as follows: Type 1, OA separate from the aneurysm; Type 2, OA from the aneurysm neck; and Type 3, OA from the aneurysm dome. Clinical outcome was assessed using the modified Rankin Scale, and visual deficits were categorized as transient or permanent. RESULTS The cumulative number of small paraophthalmic aneurysms treated with PED between 2009 and 2015 at the 4 participating institutions was 69 in 52 patients (54.1 ± 13.7 years of age) with a male-to-female ratio of 1:12. The distribution of OA origin was 72.5% for Type 1, 17.4% for Type 2, and 10.1% for Type 3. Radiographic outcome at the last follow-up (median 11.5 months) was available for 54 aneurysms (78.3%) with complete, near-complete, and incomplete occlusion rates of 81.5%, 5.6%, and 12.9%, respectively. Two aneurysms (3%) resulted in transient visual deficits, and no patient experienced a permanent visual deficit. At the last follow-up, the OA was patent in 96.8% of treated aneurysms. Type 3 OA origin was associated with a lower rate of complete aneurysm occlusion (p = 0.0297), demonstrating a trend toward visual deficits (p = 0.0797) and a lower rate of OA patency (p = 0.0783). CONCLUSIONS Pipeline embolization treatment of small paraophthalmic aneurysms is safe and effective. An aneurysm where the OA arises from the aneurysm dome may be associated with lower rates of aneurysm occlusion, OA patency, and higher rates of transient visual deficits.

Vein of Galen aneurysmal malformations: critical analysis of the literature with proposal of a new classification system

Vein of Galen aneurysmal malformations are a rare and diverse group of entities with a complex anatomy, pathophysiology, and serious clinical sequelae. Due to their complexity, there is no uniform treatment paradigm. Furthermore, treatment itself entails the risk of serious complication. Offering the best treatment option is dependent on an understanding of the aberrant anatomy and pathophysiology of these entities, and tailored therapy is recommended. Herein, the authors review the current concepts related to vein of Galen aneurysmal malformations and suggest a new classification system excluding mesodiencephalic plexiform intrinsic arteriovenous malformations from this group of malformations.

Antifibrinolytic therapy in aneurysmal subarachnoid hemorrhage increases the risk for deep venous thrombosis: A case–control study

OBJECTIVES Aneurysm re-rupture is associated with significant morbidity and mortality in aneurysmal subarachnoid hemorrhage (aSAH). While antifibrinolytics reduce aneurysm re-rupture rates, they have been associated with hydrocephalus, delayed cerebral ischemia, and venous thrombosis. We performed a case-control study in patients enrolled in the Cerebral Aneurysm Renin Angiotensin System (CARAS) study to evaluate the impact of short course (<48 h) ɛ-aminocaproic acid (EACA) on deep venous thrombosis (DVT) rates. PATIENTS AND METHODS A case-control study design was utilized to evaluate the effect of EACA on DVT formation. All cases and controls were obtained from the CARAS study, a prospective, blinded study assessing the association of polymorphisms in the renin angiotensin system and aSAH. RESULTS One hundred and twenty-eight eligible patients were enrolled in CARAS. Overall, 48 (37.5%) patients were screened for DVT, 57 (44.5%) patients were treated with short course (<48 h) EACA, and 8 (6.3%) patients suffered a re-rupture (4 treated with EACA). Ten patients (7.8%) were diagnosed with DVT as evidenced by Doppler US and represent the cases. Twenty controls without evidence of a DVT matched for age, sex, race, tobacco history, Hunt-Hess score, Fisher grade, body mass index, and length of stay were identified from the remaining pool of 118 patients. EACA was found to significantly increase the risk of DVT formation in patients with aSAH (OR 8.49, CI 1.27-77.1). CONCLUSION Short course (<48 h) administration of EACA in patients with aneurysmal subarachnoid hemorrhage is associated with an 8.5 times greater risk of DVT formation.

External ventricular drain placement in the intensive care unit versus operating room: Evaluation of complications and accuracy

OBJECTIVE External ventricular drain (EVD) placement is a common neurosurgical procedure performed in both the intensive care unit (ICU) and operating room (OR). The optimal setting for EVD placement in regard to safety and accuracy of placement is poorly defined. METHODS A retrospective chart review was performed on 150 consecutive patients who underwent EVD placement at a tertiary care center from January of 2013 to February of 2014. Clinical and radiographic data were obtained and used to compare safety and accuracy of placement between EVDs placed in the ICU versus OR. RESULTS One hundred and thirty eight patients were evaluated. Complications (hemorrhage, infection, non-functional drain) occurred in 21.5% of ICU placements and 6.7% of OR placements (p = 0.028). Grade 1, 2, and 3 placements occurred in 67.7%, 25.8%, and 6.5% of ICU placements, respectively, versus 55.6%, 42.2%, and 2.2% of OR placements (p = 0.258). No patient who received pre-placement antibiotics suffered a ventriculostomy associated infection (VAI). CONCLUSION Patients who underwent ventriculostomy placement in the ICU differed in important ways (i.e. indication for placement and the administration of pre-procedure prophylactic antibiotics) from patients treated in the OR. However, the available data suggests that complications of hemorrhage, infection, and non-functional drains may be mitigated by ventriculostomy placement in the OR.

Arterial supply of the lower cranial nerves: A comprehensive review

The lower cranial nerves receive their arterial supply from an intricate network of tributaries derived from the external carotid, internal carotid, and vertebrobasilar territories. A contemporary, comprehensive literature review of the vascular supply of the lower cranial nerves was performed. The vascular supply to the trigeminal, facial, vestibulocochlear, glossopharyngeal, vagus, spinal accessory, and hypoglossal nerves are illustrated with a special emphasis on clinical issues. Frequently the external carotid, internal carotid, and vertebrobasilar territories all contribute to the vascular supply of an individual cranial nerve along its course. Understanding of the vasculature of the lower cranial nerves is of great relevance for skull base surgery. Clin. Anat. 27:108–117, 2014.

Association of nosocomial infections with delayed cerebral ischemia in aneurysmal subarachnoid hemorrhage

OBJECTIVE Delayed cerebral ischemia (DCI) is a recognized complication of aneurysmal subarachnoid hemorrhage (aSAH) that contributes to poor outcome. This study seeks to determine the effect of nosocomial infection on the incidence of DCI and patient outcome. METHODS An exploratory analysis was performed on 156 patients with aSAH enrolled in the Cerebral Aneurysm Renin Angiotensin System study. Clinical and radiographic data were analyzed with univariate analysis to detect risk factors for the development of DCI and poor outcome. Multivariate logistic regression was performed to identify independent predictors of DCI. RESULTS One hundred fifty-three patients with aSAH were included. DCI was identified in 32 patients (20.9%). Nosocomial infection (odds ratio [OR] 3.5, 95% confidence interval [CI] 1.09-11.2, p = 0.04), ventriculitis (OR 25.3, 95% CI 1.39-458.7, p = 0.03), aneurysm re-rupture (OR 7.55, 95% CI 1.02-55.7, p = 0.05), and clinical vasospasm (OR 43.4, 95% CI 13.1-143.4, p < 0.01) were independently associated with the development of DCI. Diagnosis of nosocomial infection preceded the diagnosis of DCI in 15 (71.4%) of 21 patients. Patients diagnosed with nosocomial infection experienced significantly worse outcomes as measured by the modified Rankin Scale score at discharge and 1 year (p < 0.01 and p = 0.03, respectively). CONCLUSIONS Nosocomial infection is independently associated with DCI. This association is hypothesized to be partly causative through the exacerbation of systemic inflammation leading to thrombosis and subsequent ischemia.

Extracranial traumatic aneurysms due to blunt cerebrovascular injury

OBJECT Traumatic aneurysms occur in 10% of extracranial blunt traumatic cerebrovascular injuries (TCVI). The clinical consequences and optimal management of traumatic aneurysms are poorly understood. METHODS A prospective study of TCVI at a Level I trauma center identified 7 patients with 19 extracranial traumatic carotid artery or vertebral artery aneurysms. An additional 6 patients with 7 traumatic aneurysms were followed outside of the prospective study, giving a total of 13 patients with 26 traumatic aneurysms. All patients were treated with 325 mg aspirin daily and underwent clinical and imaging follow-up beyond the initial hospitalization. Endovascular treatment was reserved for aneurysms demonstrating significant enlargement on follow-up imaging. Clinical and radiographic features were assessed. RESULTS The 7 patients with traumatic aneurysms identified in the prospective cohort comprised 10.3% of all patients with TCVI. Two (15.4%) of the 13 total patients suffered an ischemic stroke in the setting of TCVI with traumatic aneurysm formation. No patient experienced an ischemic stroke or new symptoms after the initiation of antiplatelet therapy. Clinical and radiographic follow-up averaged 15.8 months (range 0.4-41.7 months) and 22.0 months (range 6.6-55.7 months), respectively. Ten (38.5%) of 26 aneurysms were not visualized on last follow-up, 10 (38.5%) were smaller, 1 (3.8%) was unchanged, and 5 (19.2%) were larger. Saccular aneurysms were more likely to enlarge than fusiform aneurysms (33.3% vs 11.8%). Results of a Fisher exact test tend to support the assertion that the 2 different aneurysm morphologies behave differently (p = 0.07). Two saccular aneurysms were treated with stenting. CONCLUSIONS The majority of traumatic aneurysms can be managed with an antiplatelet regimen of 325 mg aspirin daily and serial imaging. Saccular aneurysms have a greater tendency to enlarge when compared with fusiform aneurysms.

Validation and modification of a predictive model of postresection hydrocephalus in pediatric patients with posterior fossa tumors

OBJECT Postresection hydrocephalus is observed in approximately 30% of pediatric patients with posterior fossa tumors. However, which patients will develop postresection hydrocephalus is not known. The Canadian Preoperative Prediction Rule for Hydrocephalus (CPPRH) was developed in an attempt to identify this subset of patients, allowing for the optimization of their care. The authors sought to validate and critically appraise the CPPRH. METHODS The authors conducted a retrospective chart review of 99 consecutive pediatric patients who presented between 2002 and 2010 with posterior fossa tumors and who subsequently underwent resection. The data were then analyzed using bivariate and multivariate analyses, and a modified CPPRH (mCPPRH) was applied. RESULTS Seventy-six patients were evaluated. Four variables were found to be significant in predicting postresection hydrocephalus: age younger than 2 years, moderate/severe hydrocephalus, preoperative tumor diagnosis, and transependymal edema. The mCPPRH produced observed likelihood ratios of 0.737 (95% CI 0.526-1.032) and 4.688 (95% CI 1.421-15.463) for low- and high-risk groups, respectively. CONCLUSIONS The mCPPRH utilizes readily obtainable and reliable preoperative variables that together stratify children with posterior fossa tumors into high- and low-risk categories for the development of postresection hydrocephalus. This new predictive model will aid patient counseling and tailor the intensity of postoperative clinical and radiographic monitoring for hydrocephalus, as well as provide evidence-based guidance for the use of prophylactic CSF diversion.

Use of Platelet Function Testing Before Pipeline Embolization Device Placement: A Multicenter Cohort Study

Background and Purpose— Thromboembolic complications constitute a significant source of morbidity after neurointerventional procedures. Flow diversion using the pipeline embolization device for the treatment of intracranial aneurysms necessitates the use of dual antiplatelet therapy to reduce this risk. The use of platelet function testing before pipeline embolization device placement remains controversial. Methods— A retrospective review of prospectively maintained databases at 3 academic institutions was performed from the years 2009 to 2016 to identify patients with intracranial aneurysms treated with pipeline embolization device placement. Clinical and radiographic data were analyzed with emphasis on thromboembolic complications and clopidogrel responsiveness. Results— A total of 402 patients underwent 414 pipeline embolization device procedures for the treatment of 465 intracranial aneurysms. Thromboembolic complications were encountered in 9.2% of procedures and were symptomatic in 5.6%. Clopidogrel nonresponders experienced a significantly higher rate of thromboembolic complications compared with clopidogrel responders (17.4% versus 5.6%). This risk was significantly lower in nonresponders who were switched to ticagrelor when compared with patients who remained on clopidogrel (2.7% versus 24.4%). In patients who remained on clopidogrel, the rate of thromboembolic complications was significantly lower in those who received a clopidogrel boost within 24 hours pre-procedure when compared with those who did not (9.8% versus 51.9%). There was no significant difference in the rate of hemorrhagic complications between groups. Conclusions— Clopidogrel nonresponders experienced a significantly higher rate of thromboembolic complications when compared with clopidogrel responders. However, this risk seems to be mitigated in nonresponders who were switched to ticagrelor or received a clopidogrel boost within 24 hours pre-procedure.