Ticagrelor resistance: a case series and algorithm for management of non-responders.

The placement of cervical and intracranial stents requires the administration of antiplatelet drugs to prevent thromboembolic complications. Ticagrelor has emerged as the most widely used alternative in clopidogrel non-responders owing to its potent antiplatelet effects. Because ticagrelor does not require hepatic activation, many neurointerventionalists choose to forgo laboratory testing of platelet inhibition. In rare instances, patients may not achieve adequate platelet inhibition following ticagrelor administration. In this paper we review the mechanism of action of ticagrelor and its use in cerebrovascular procedures. We present two cases of ticagrelor non-responsiveness from two high-volume cerebrovascular centers, discuss their management, and propose an algorithm for managing ticagrelor non-responsiveness.

Early chemoprophylaxis for deep venous thrombosis does not increase the risk of hematoma expansion in patients presenting with spontaneous intracerebral hemorrhage.

BACKGROUND: Spontaneous intracerebral hemorrhage (ICH) is a significant cause of morbidity and mortality worldwide. The development of venous thromboembolism (VTE), including deep venous thrombosis or pulmonary embolism, is correlated with negative outcomes following ICH. Due to the risk of hematoma expansion associated with the use of VTE chemoprophylaxis, there remains significant debate about the optimal timing for its initiation following ICH. We analyzed the risk of early chemoprophylaxis on hematoma expansion following ICH. METHODS: We performed a retrospective analysis of patients presenting with spontaneous ICH at single institution between 2011 and 2018. The rate of hematoma expansion was compared between patients that received early chemoprophylaxis (on admission) and those that received conventional chemoprophylaxis (>24 h). RESULTS: Data for 235 patients were available for analysis. Eleven patients (7.5%) in the early prophylaxis cohort and seven patients (8.0%) in the conventional prophylaxis cohort developed VTE (P = 0.9). Hematoma expansion also did not differ significantly (early 19%, conventional 23%, P = 0.5). CONCLUSION: The use of early chemoprophylaxis against venous thromboembolic events following ICH appears safe in our patient population without increasing the risk of hematoma expansion. Given the increased risk of poor outcome in the setting of VTE, early VTE chemoprophylaxis should be considered in patients who present with ICH. Larger, prospective, and randomized studies are necessary to better elucidate the risk of early chemoprophylaxis and potential reduction in venous thromboembolic events.

Trends in Hospital-to-Hospital Transfers for Aneurysmal Subarachnoid Hemorrhage: A Single-Institution Experience from 2006 to 2017.

BACKGROUND: Despite evidence to support that aneurysmal subarachnoid hemorrhage (aSAH) is best treated at high-volume centers, it is unknown whether clinical practice reflects these findings. METHODS: We analyzed patients transferred to our high-volume center for aSAH between 2006 and 2017. Data collection included number of transfers, demographic data, Hunt and Hess score, Fisher score, comorbid conditions, length of stay (LOS), discharge disposition, in-hospital mortality rates, insurance status, and hospital charges. Comparisons were made across 3 time periods (2006-2009, 2010-2013, and 2014-2017) and included subgroup analyses by treatment modality (endovascular vs. microsurgical). RESULTS: aSAH transfers declined from 213 in 2006-2009 to 160 in 2014-2017. While there was no change in presenting Hunt and Hess scores, the percentage of modified Fisher scores of 4 increased from 2006-2009 to 2014-2017. Transferred patients had a greater comorbidity index and decreased predicted 10-year survival. Despite this, the average LOS decreased. In-hospital mortality decreased from 2006-2009 to 2014-2017, especially in the endovascular cohort. The proportions of patients who were either self-pay or Medicaid did not change. Overall inflation-adjusted hospital charges decreased from $76,975 in 2006-2009 to $59,870 in 2014-2017. CONCLUSIONS: Between 2006 and 2017, transfers to our center for aSAH declined. However, transferred patients had greater levels of complexity, more comorbidities, and were at greater risk for vasospasm based on their presenting Fisher score. Nonetheless, average LOS, in-hospital mortality, and cost declined. These changing referral patterns have implications for outcome data, quality reporting, resident education, and developing systems of care to optimize outcomes.

Transnasal and Transoral Approaches to Atlantoaxial Synovial Cysts: Report of 3 Cases and Review of the Literature.

BACKGROUND: Synovial cysts are cystic masses lined with pseudostratified columnar cells and containing clear or xanthochromic fluid. Although they are commonly encountered in the lumbar spine, synovial cysts infrequently occur in the cervical spine and rarely involve the odontoid process. The causes of synovial cysts of the odontoid process are unknown, but growth of synovial rests, proliferation of multipotent mesenchymal cells, atlantoaxial instability, and trauma are thought to play a role. CASE DESCRIPTION: We present 3 cases of atlantoaxial cysts with the associated radiographic features, surgical management, and clinical outcomes. No patient had rheumatoid arthritis. In all cases, preoperative differential diagnosis included neoplastic pathologic changes. Two patients underwent odontoidectomy through either an endonasal or a transoral approach, followed by posterior occipitocervical fusion. The third patient underwent an endoscopic transsphenoidal approach for cyst decompression. CONCLUSIONS: Tissue diagnosis is important in confirming pathologic analysis because synovial cysts have radiographic characteristics similar to those of a wide variety of neoplasms of the craniovertebral junction.

Morphometric and volumetric comparison of 102 children with symptomatic and asymptomatic Chiari malformation Type I.

OBJECTIVE Chiari malformation Type I (CM-I) is typically defined on imaging by a cerebellar tonsil position ≥ 5 mm below the foramen magnum. Low cerebellar tonsil position is a frequent incidental finding on brain or cervical spine imaging, even in asymptomatic individuals. Nonspecific symptoms (e.g., headache and neck pain) are common in those with low tonsil position as well as in those with normal tonsil position, leading to uncertainty regarding appropriate management for many patients with low tonsil position and nonspecific symptoms. Because cerebellar tonsil position is not strictly correlated with the presence of typical CM-I symptoms, the authors sought to determine if other 2D morphometric or 3D volumetric measurements on MRI could distinguish between patients with asymptomatic and symptomatic CM-I. METHODS The authors retrospectively analyzed records of 102 pediatric patients whose records were in the University of Michigan clinical CM-I database. All patients in this database had cerebellar tonsil position ≥ 5 mm below the foramen magnum. Fifty-one symptomatic and 51 asymptomatic patients were matched for age at diagnosis, sex, tonsil position, and tonsil morphology. National Institutes of Health ImageJ software was used to obtain six 2D anatomical MRI measurements, and a semiautomated segmentation tool was used to obtain four 3D volumetric measurements of the posterior fossa and CSF subvolumes on MRI. RESULTS No significant differences were observed between patients with symptomatic and asymptomatic CM-I related to tentorium length (50.3 vs 51.0 mm; p = 0.537), supraoccipital length (39.4 vs 42.6 mm; p = 0.055), clivus-tentorium distance (52.0 vs 52.1 mm; p = 0.964), clivus-torcula distance (81.5 vs 83.3 mm; p = 0.257), total posterior fossa volume (PFV; 183.4 vs 190.6 ml; p = 0.250), caudal PFV (152.5 vs 159.8 ml; p = 0.256), fourth ventricle volume to caudal PFV ratio (0.0140 vs 0.0136; p = 0.649), or CSF volume to caudal PFV ratio (0.071 vs 0.061; p = 0.138). CONCLUSIONS No clinically useful 2D or 3D measurements were identified that could reliably distinguish pediatric patients with symptoms attributable to CM-I from those with asymptomatic CM-I.

Sports participation with Chiari I malformation.

OBJECT There is currently no consensus on the safety of sports participation for patients with Chiari I malformation (CM-I). The authors' goal was to define the risk of sports participation for children with the imaging finding of CM-I. METHODS A prospective survey was administered to 503 CM-I patients at 2 sites over a 46-month period. Data were gathered on imaging characteristics, treatment, sports participation, and any sport-related injuries. Additionally, 81 patients completed at least 1 subsequent survey following their initial entry into the registry and were included in a prospective group, with a mean prospective follow-up period of 11 months. RESULTS Of the 503 CM-I patients, 328 participated in sports for a cumulative duration of 4641 seasons; 205 of these patients participated in contact sports. There were no serious or catastrophic neurological injuries. One patient had temporary extremity paresthesias that resolved within hours, and this was not definitely considered to be related to the CM-I. In the prospective cohort, there were no permanent neurological injuries. CONCLUSIONS No permanent or catastrophic neurological injuries were observed in CM-I patients participating in athletic activities. The authors believe that the risk of such injuries is low and that, in most cases, sports participation by children with CM-I is safe.

Sports participation with arachnoid cysts.

OBJECT There is currently no consensus on the safety of sports participation for patients with an intracranial arachnoid cyst (AC). The authors' goal was to define the risk of sports participation for children with this imaging finding. METHODS A survey was prospectively administered to 185 patients with ACs during a 46-month period at a single institution. Cyst size and location, treatment, sports participation, and any injuries were recorded. Eighty patients completed at least 1 subsequent survey following their initial entry into the registry, and these patients were included in a prospective registry with a mean prospective follow-up interval of 15.9 ± 8.8 months. RESULTS A total 112 patients with ACs participated in 261 sports for a cumulative duration of 4410 months or 1470 seasons. Of these, 94 patients participated in 190 contact sports for a cumulative duration of 2818 months or 939 seasons. There were no serious or catastrophic neurological injuries. Two patients presented with symptomatic subdural hygromas following minor sports injuries. In the prospective cohort, there were no neurological injuries CONCLUSIONS Permanent or catastrophic neurological injuries are very unusual in AC patients who participate in athletic activities. In most cases, sports participation by these patients is safe.

Retroperitoneal course of iliohypogastric, ilioinguinal, and genitofemoral nerves: A study to improve identification and excision during triple neurectomy.

Triple neurectomy of the iliohypogastric (IHN), ilioinguinal (IIN), and genitofemoral (GFN) nerves is an available treatment option for chronic groin pain when conservative measures are ineffective. This research study attempted to define the variability of IHN, IIN, and GFN by categorizing variation and establishing a relationship to clinically significant landmarks. 22 cadavers (43 specimens) were dissected. Age, gender, ethnicity, BMI, and pertinent medical history were recorded for each specimen. Nerve emergence, insertion, and split points were measured in relation to clinically significant landmarks. Retroperitoneal trajectories of IHN, IIN, and GFN were analyzed and categorized based on nerve branching patterns. IIN and IHN had three branching patterns - type A (47%) in which the IIH and IIN exit as separate branches; type B (26%) in which the IIH and IIN exit as a single bundle and split; and type C (28%) in which the IIH and IIN exit and do not split. The GFN had three branching patterns--type 1 (50%) in which the GFN exited from the psoas major and then split into the genital and femoral branches; type 2 (30%) in which the GFN exited and did not split; and type 3 (20%) in which the GFN exited the psoas major already split into the genital and femoral branches. Variations in the IHN, IIN, and GFN nerves outlined in this study will provide surgeons with clinically useful information aiding in successful and efficient localization of these nerves during retroperitoneal procedures, including laparoscopic triple neurectomy.