Outcomes in patients with large vessel occlusion strokes undergoing mechanical thrombectomy with concurrent COVID-19: a nationwide retrospective analysis

BACKGROUND

Preliminary studies show that patients with large vessel occlusion (LVO) acute ischemic strokes have worse outcomes with concurrent COVID-19 infection. We investigated the outcomes for patients with LVO strokes undergoing mechanical thrombectomy (MT) with concurrent COVID-19 infection.

METHODS

The National Inpatient Database (NIS) was used for our analysis. Patients in the year 2020 with an ICD-10 diagnosis code for acute ischemic stroke and procedural code for MT were included with and without COVID-19. Odds ratios (OR) were calculated using a logistic regression model with age, sex, stroke location, Elixhauser comorbidity score, and other patient variables deemed clinically relevant as covariates.

RESULTS

Patients in the COVID-19 group were younger (64.3±14.4 vs 69.4±14.5 years, P<0.001), had a higher rate of inpatient mortality (22.4% vs 10.1%, P<0.001), and a longer length of stay (10 vs 6 days, P<0.001). Patients with COVID-19 had higher odds of death (OR 2.78, 95% CI 2.11 to 3.65) and lower odds of a routine discharge (OR 0.65, 95% CI 0.48 to 0.89). There was no difference in the odds of subsequent stroke and cerebral hemorrhage, but patients with COVID-19 had statistically significantly higher odds of respiratory failure, pulmonary embolism, deep vein thrombosis, myocardial infarction, acute kidney injury, and sepsis.

CONCLUSIONS

Patients with LVOs undergoing MT within the 2020 NIS database had worse outcomes when co-diagnosed with COVID-19, likely due to non-neurological manifestations of COVID-19.

Balloon-mounted covered stent as endovascular management of a traumatic cervical internal carotid artery pseudoaneurysm in a 23-year-old: a case report

Background

Distal cervical internal carotid artery (cICA) pseudoaneurysms are uncommon. They may lead to thromboembolic or hemorrhagic complications, especially in young adults. We report one of the first cases in the literature regarding the management via PK Papyrus (Biotronik, Lake Oswego, Oregon, USA) balloon-mounted covered stent of a 23-year-old male with an enlarging cervical carotid artery pseudoaneurysm and progressive internal carotid artery stenosis.

Case Description

We report the management of a 23-year-old male with an enlarging cervical carotid artery pseudoaneurysm and progressive internal carotid artery stenosis. Based on clinical judgment and imaging analysis, the best option to seal the aneurysm was a PK Papyrus 5×26 balloon-mounted covered stent. A follow-up angiogram showed no residual filling of the pseudoaneurysm, but there was some contrast stagnation just proximal to the stent, which is consistent with a residual dissection flap. We then deployed another PK Papyrus 5×26 balloon-mounted covered stent, providing some overlap at the proximal end of the stent. An angiogram following this subsequent deployment demonstrated complete reconstruction of the cICA with no residual evidence of pseudoaneurysm or dissection flap. There were no residual in-stent stenosis or vessel stenosis. The patient was discharged the day after the procedure with no complications.

Conclusions

These positive outcomes support the use of a balloon-mounted covered stent as a safe and feasible modality with high technical success for endovascular management of pseudoaneurysm.

Perioperative Outcomes in Transcarotid Artery Revascularization Versus Carotid Endarterectomy or Stenting Nationwide

BACKGROUND AND OBJECTIVES

Transcarotid artery revascularization (TCAR) is a newer treatment for carotid stenosis where the carotid artery is accessed directly in the neck for stenting. It is less invasive than carotid endarterectomy (CEA) and has less embolic potential than carotid artery stenting (CAS), but population-level utilization of TCAR and outcomes are currently unknown. Our study compares outcomes of TCAR with those of CEA and CAS.

METHODS

The National Inpatient Database was used for years 2015 to 2019. A multivariate logistic regression model was used to compare CEA, CAS, and TCAR outcomes with age, sex, race, hospital teaching status, symptomatic carotid disease status, side of procedure, intraoperative monitoring, and the weighted Elixhauser comorbidity score as covariates.

RESULTS

TCAR comprised 0.69% of these procedures in 2016, rising to 1.35% in 2019. The inpatient rates of death, stroke, and myocardial infarction for TCAR were 0.63% (95% confidence interval: 0.36%, 1.06%), 0.42% (0.21%, 0.80%), and 1.46% (1.04%, 2.05%), respectively. Compared with CEA, TCAR had statistically insignificant difference odds of death, odds ratio (95% CI) for stroke was 0.47 (0.25, 0.87), and for myocardial infarction, it was 0.66 (0.37, 0.94). Compared with CAS, for TCAR, the odds ratio for death was 0.41 (0.24, 0.71), and for stroke, it was 0.48 (0.26, 0.91).

CONCLUSION

TCAR is underutilized relative to other revascularization techniques yet has favorable outcomes compared with CEA and CAS. TCAR may be preferred to CAS in patients not surgical candidates for CEA and has a less invasive possibility for those eligible for CEA.

The effect of occlusion location and technique in mechanical thrombectomy for minor stroke

INTRODUCTION

Endovascular mechanical thrombectomy (MT) is an established treatment for large vessel occlusion strokes with a National Institutes of Health Stroke Scale (NIHSS) score of 6 or higher. Data pertaining to minor strokes, medium, or distal vessel occlusions, and most effective MT technique is limited and controversial.

METHODS

A multicenter retrospective study of all patients treated with MT presenting with NIHSS score of 5 or less at 29 comprehensive stroke centers. The cohort was dichotomized based on location of occlusion (proximal vs. distal) and divided based on MT technique (direct aspiration first-pass technique [ADAPT], stent retriever [SR], and primary combined [PC]). Outcomes at discharge and 90 days were compared between proximal and distal occlusion groups, and across MT techniques.

RESULTS

The cohort included 759 patients, 34% presented with distal occlusion. Distal occlusions were more likely to present with atrial fibrillation (p = 0.008) and receive IV tPA (p = 0.001). Clinical outcomes at discharge and 90 days were comparable between proximal and distal groups. Compared to SR, patients managed with ADAPT were more likely to have a modified Rankin Scale of 0-2 at discharge and at 90 days (p = 0.024 and p = 0.013). Primary combined compared to ADAPT, prior stroke, multiple passes, older age, and longer procedure time were independently associated with worse clinical outcome, while successful recanalization was positively associated with good clinical outcomes.

CONCLUSIONS

Proximal and distal occlusions with low NIHSS have comparable outcomes and safety profiles. While all MT techniques have a similar safety profile, ADAPT was associated with better clinical outcomes at discharge and 90 days.

Concurrent bacterial endocarditis is associated with worse inpatient outcomes for large vessel occlusions

BACKGROUND

Neurological complications of bacterial endocarditis (BE) are common, including acute ischemic stroke (AIS). Although mechanical thrombectomy (MT) is effective for large vessel occlusion (LVO) stroke, data are limited on MT for LVOs in patients with endocarditis. We assess outcomes in patients treated with thrombectomy for LVOs with concurrent BE.

METHODS

The National Inpatient Sample (NIS) was used. The NIS was queried from October 2015-2019 for patients receiving MT for LVO of the middle cerebral artery. Odds ratios (OR) were calculated using a multivariate logistic regression model.

RESULTS

A total of 635 AIS with BE patients and 57 420 AIS only patients were identified undergoing MT. AIS with BE patients had a death rate of 26.8% versus 10.2% in the stroke alone cohort, and were also less likely to have a routine discharge (10.2% vs 20.9%, both P<0.0001). AIS with BE patients had higher odds of death (OR 3.94) and lower odds of routine discharge (OR 0.23). AIS with BE patients also had higher rates of post-treatment cerebral hemorrhage, 39.4% vs 23.7%, with an OR of 2.20 (P<0.0001 for both analyses). These patients also had higher odds of other complications, including hydrocephalus, respiratory failure, acute kidney injury, and sepsis.

CONCLUSION

While MT can be used to treat endocarditis patients with LVOs, these patients have worse outcomes. Additional investigations should be undertaken to better understand their clinical course, and further develop treatments for endocarditis patients with stroke.

Clinical course of pediatric gunshot wounds involving the spine and spinal cord: the Miami experience

OBJECTIVE

Civilian gunshot wounds (GSWs) involving the skeletal spine and spinal cord in pediatric patients are fortunately rare. Nevertheless, their presentation mandates judicious evaluation, and their clinical outcomes remain poorly defined. Thus, the authors aimed to characterize the clinical course of this traumatic presentation in the pediatric population based on their institutional experience.

METHODS

A retrospective review of a level I trauma center database was performed for the period 2011-2021. Clinical data were included for patients aged ≤ 18 years who had presented with radiographic and clinical evidence of a GSW to the spine and had at least one documented follow-up at least 6 months after injury. The primary outcomes of the study were the categorization of gunshot injuries and the results of neurological and functional examinations.

RESULTS

A total of 13 patients satisfied the study selection criteria. The mean patient age was 15.7 ± 1.6 years, and all presentations were assault in nature. Most of the patients were male (n = 12, 92%) in gender, Black in race (n = 11, 85%), and from zip codes with a median household income below the local county average (n = 10, 77%). All patients presented with a minimum Glasgow Coma Scale score of 14. Examination at presentation revealed American Spinal Injury Association Impairment Scale (AIS) grade A in 3 cases (23%), grade B in 2 (15%), grade C in 1 (8%), grade D in 2 (15%), and grade E in 5 (38%). Gunshot injury involved all regions of the spine, most commonly the cervical and thoracic spine (n = 6 for each, 46%). In terms of skeletal injury, the most common injuries were to the facet (n = 10, 77%) and the pedicle (n = 8, 62%), with evidence of intracanal injury in 9 patients (69%). Neurosurgical intervention was pursued in 1 patient (8%). Overall, 7 patients (54%) experienced a complication during admission, and the median length of hospitalization was 12 days (range 1-88 days) without any mortality events. Within 90 days from discharge, 2 patients (15%) were readmitted to the hospital for further care. The mean follow-up was 28.9 months (range 6-74 months), by which only 1 patient (8%) had an improved AIS examination; all other patients remained at their initial AIS grade.

CONCLUSIONS

Pediatric GSWs involving the spine are typically nonfatal presentations, and their long-term functional outlook appears contingent on clinical examination findings at initial presentation. Although neurosurgical intervention is not necessary in most cases, judicious evaluation of radiographic and clinical examinations by a neurosurgical team is strongly recommended to optimize recovery.

Treatment-Associated Stroke in Patients Undergoing Endovascular Therapy in the ARUBA Trial

Background and Purpose

Since the publication of ARUBA trial (A Randomized Trial of Unruptured Brain Arteriovenous Malformations), outcomes in treated and untreated patients with unruptured arteriovenous malformation have been thoroughly compared. However, no prior analysis of ARUBA patients has sought to identify risk factors for perioperative stroke. Improved understanding of risks within the ARUBA cohort will help clinicians apply the study’s findings in a broader context.

Methods

The National Institute of Neurological Disorders and Stroke database was queried for all data relating to ARUBA patients, including demographics, interventions undertaken, and timing of stroke. Retrospective cohort analysis was performed with the primary outcome of perioperative stroke in patients who underwent endovascular intervention, and stroke risk was modeled with multivariate analysis.

Results

A total of 64 ARUBA patients were included in the analysis. One hundred and fifty-ninth interventions were performed, and 26 (16%) procedures resulted in stroke within 48 hours of treatment. Posterior cerebral artery supply (adjusted odds ratio, 4.42 [95% CI, 1.23–15.9], P=0.02) and Spetzler-Martin grades 2 and 3 arteriovenous malformation (adjusted odds ratio, 7.76 [95% CI, 1.20–50.3], P=0.03; 9.64 [95% CI, 1.36–68.4], P=0.04, respectively) were associated with increased perioperative stroke risk in patients who underwent endovascular intervention. Patients treated in the United States or Germany had a significantly lower stroke risk than patients treated in other countries (adjusted odds ratio, 0.18 [95% CI, 0.04–0.82], P=0.02).

Conclusions

Knowing patient and lesion characteristics that increase risk during endovascular treatment can better guide clinicians managing unruptured brain arteriovenous malformation. Our analysis suggests risk of perioperative stroke is dependent on Spetzler-Martin grade and posterior-circulation arterial supply. Differences in regional treatment paradigms may also affect stroke risk.

Fusiform Dilatation of the Internal Carotid Artery in Childhood-Onset Craniopharyngioma- A Systematic Review

OBJECTIVE

Patients with fusiform dilation of the internal carotid artery (FDCA) following pediatric craniopharyngioma resection typically have a benign clinical course. We sought to review the neurosurgical literature for FDCA outcomes after resection of these tumors.

METHODS

Using PubMed, Web of Science, and Cochrane databases we identified surgical series or case reports reporting incidences of FDCA following craniopharyngioma resection. Inclusion criteria included FDCA outcomes reported specifically after craniopharyngioma resection, with at least 6 months of follow-up data.

RESULTS

Our literature search yielded 12 full-text articles. This resulted in a total of 799 patients (376, 52.3% males). The weighted mean follow-up was 74.8 (9-140) months. The majority of tumors were found to be suprasellar (62.1%), with traditional microsurgery being more commonly employed than endoscopic endonasal surgery (80.9% versus 19.1%). Gross total resection was achieved in 42.6% of cases. A total of 55 aneurysms were reported, most commonly occurring at the terminal internal carotid artery (ICA) (66.7%) . Aneurysmal progression on follow-up occurred in 10 (18.5%) cases, with no reports of rupture. A total of 10 (18.2%) of aneurysms were treated with clipping, endovascular, or bypass techniques.

CONCLUSIONS

FDCA is a rare complication following pediatric craniopharyngioma resection. The exact cause is unclear, and factors related to tumor invasiveness, size, location, and differences in surgical approach all may contribute to FDCA development. The majority of patients who go on to develop FDCA follow an innocuous course on follow-up, with no reports of rupture in the present literature. For this reason, patients rarely require surgical or endovascular intervention for these lesions, and conservative management is favored.

Dose Adjustment Associated Complications of Bone Morphogenetic Protein: A Longitudinal Assessment

OBJECTIVE

Bone morphogenetic protein (BMP) is a growth factor that aids in osteoinduction and promotes bone fusion. There is a lack of literature regarding recombinant human BMP-2 (rhBMP-2) dosage in different spine surgeries. This study aims to investigate the trends in rhBMP-2 dosage and the associated complications in spinal arthrodesis.

METHODS

A retrospective study was conducted investigating spinal arthrodesis using rhBMP-2. Variables including age, procedure type, rhBMP-2 size, complications, and postoperative imaging were collected. Cases were grouped into the following surgical procedures: anterior lumbar interbody fusion/extreme lateral interbody fusion (ALIF/XLIF), posterior lumbar interbody fusion/transforaminal lumbar interbody fusion (PLIF/TLIF), posterolateral fusion (PLF), anterior cervical discectomy and fusion (ACDF), and posterior cervical fusion (PCF).

RESULTS

A total of 1209 patients who received rhBMP-2 from 2006 to 2020 were studied. Of these, 230 were categorized as ALIF/XLIF, 336 as PLIF/TLIF, 243 as PLF, 203 as ACDF, and 197 as PCF. PCF (P < 0.001), PLIF/TLIF (P < 0.001), and PLF (P < 0.001) demonstrated a significant decrease in the rhBMP-2 dose used per level, with major transitions seen in 2018, 2011, and 2013, respectively. In our sample, 129 complications following spinal arthrodesis were noted. A significant relation between rhBMP-2 size and complication rates (χ²= 73.73, P = 0.0029) was noted. rhBMP-2 dosage per level was a predictor of complication following spinal arthrodesis (odds ratio = 1.302 [1.05-1.55], P < 0.001).

CONCLUSIONS

BMP is an effective compound in fusing adjacent spine segments. However, it carries some regional complications. We demonstrate a decreasing trend in the dose/vertebral level. A decrease rhBMP-2 dose per level correlated with a decrease in complication rates.

Incidence and Clinical Outcomes of Hypothyroidism in Patients Undergoing Spinal Fusion

Background

Hypothyroidism has been independently associated with the development of several comorbidities and is known to increase complication rates in non-spinal surgeries. However, there are limited data regarding the effects of hypothyroidism in major spine surgery. Therefore, we present the largest retrospective analysis evaluating outcomes in hypothyroid patients undergoing spinal fusion.

Methods

A retrospective review of the National Inpatient Sample (NIS) from 2004-2014 was performed. Patients with an International Classification of Diseases, 9th revision, Clinical Modification (ICD-9-CM) procedure code indicating spinal fusion (81.04-81.08, 81.34-81.38, 81.0x, 81.3x) were included. Patients with an ICD-9-CM diagnosis code indicating hypothyroidism (244.x) were compared to those without. Cervical and lumbar fusions were evaluated independently. Significant covariates in univariable logistic regression were utilized to construct multivariable models to analyze the effect of hypothyroidism on perioperative morbidity and mortality.

Results

A total of 4,149,125 patients were identified, of which 9.4% were hypothyroid. Although, hypothyroid patients had a higher risk of hematologic complications (lumbar - odds ratio [OR] 1.176, p < 0.0001; cervical - OR 1.162, p < 0.0001), they exhibited decreased in-hospital mortality (lumbar - OR .643, p < 0.0001; cervical - OR .606, p < 0.0001). Hypothyroid lumbar fusion patients also demonstrated decreased rates of perioperative myocardial infarction (MI) (OR .851, p < 0.0001). All these results were independent of patient gender.

Conclusions

Hypothyroid patients undergoing spinal fusion demonstrated lower rates of inpatient mortality and, in lumbar fusions, also had lower rates of acute MI when compared to their euthyroid counterparts. This suggests that hypothyroidism may offer protection against all-cause mortality and may be cardioprotective in the postoperative period for lumbar spinal fusions independent of patient gender.

Effect of Hispanic Status in Mechanical Thrombectomy Outcomes After Ischemic Stroke: Insights From STAR

Background and Purpose

Epidemiological studies have shown racial and ethnic minorities to have higher stroke risk and worse outcomes than non-Hispanic Whites. In this cohort study, we analyzed the STAR (Stroke Thrombectomy and Aneurysm Registry) database, a multi-institutional database of patients who underwent mechanical thrombectomy for acute large vessel occlusion stroke to determine the relationship between mechanical thrombectomy outcomes and race.

Methods

Patients who underwent mechanical thrombectomy between January 2017 and May 2020 were analyzed. Data included baseline characteristics, vascular risk factors, complications, and long-term outcomes. Functional outcomes were assessed with respect to Hispanic status delineated as non-Hispanic White (NHW), non-Hispanic Black (NHB), or Hispanic patients. Multivariate analysis was performed to identify variables associated with unfavorable outcome or modified Rankin Scale ≥3 at 90 days.

Results

Records of 2115 patients from the registry were analyzed. Median age of Hispanic patients undergoing mechanical thrombectomy was 60 years (72–84), compared with 63 years (54–74) for NHB, and 71 years (60–80) for NHW patients (P<0.001). Hispanic patients had a higher incidence of diabetes (41%; P<0.001) and hypertension (82%; P<0.001) compared with NHW and NHB patients. Median procedure time was shorter in Hispanics (36 minutes) compared to NHB (39 minutes) and NHW (44 minutes) patients (P<0.001). In multivariate analysis, Hispanic patients were less likely to have favorable outcome (odds ratio, 0.502 [95% CI, 0.263–0.959]), controlling for other significant predictors (age, admission National Institutes Health Stroke Scale, onset to groin time, number of attempts, procedure time).

Conclusions

Hispanic patients are less likely to have favorable outcome at 90 days following mechanical thrombectomy compared to NHW or NHB patients. Further prospective studies are required to validate our findings.

Medical Adjuvants in the Treatment of Surgically Refractory Arteriovenous Malformations of the Head and Face: Case Report and Review of Literature

BACKGROUND

Arteriovenous malformations (AVMs) of the brain and face present unique challenges for clinicians. Cerebral AVMs may induce hemorrhage or form aneurysms, while facial AVMs can cause significant disfigurement and pain. Moreover, facial AVMs often draw blood supply from arteries providing critical blood flow to other important structures of the head which may make them impossible to treat curatively. Medical adjuvants may be an important consideration in the management of these patients.

SUMMARY

We conducted a systematic review of the literature to identify other instances of molecular target of rapamycin (mTOR) inhibitors used as medical adjuvants for the treatment of cranial and facial AVMs. We also present 2 cases from our own institution where patients were treated with partial embolization, followed by adjuvant therapy with rapamycin. After screening a total of 75 articles, 7 were identified which described use of rapamycin in the treatment of inoperable cranial or facial AVM. In total, 21 cases were reviewed. The median treatment duration was 12 months (3-24.5 months), and the highest recorded dose was 3.5 mg/m2. 76.2% of patients demonstrated at least a partial response to rapamycin therapy. In 2 patients treated at our institution, symptomatic and radiographic improvement were noted 6 months after initiation of therapy. Key Messages: Early results have been encouraging in a small number of patients with inoperable AVM of the head and face treated with mTOR inhibitors. Further study of medical adjuvants such as rapamycin may be worthwhile.

Vertebral multiple myeloma with pathological fracture: the most common etiology for emergency spine surgery in patients with no cancer diagnosis on admission

OBJECTIVE

Vertebral compression fractures are common in multiple myeloma (MM). Modern treatment paradigms place emphasis on treatment with radiation, with surgery reserved for cases involving frank instability or severe neural compression. However, experience at the authors' institution has led them to suspect a more prominent role for surgical intervention in some settings. The authors undertook the present study to better understand the incidence of MM in undiagnosed patients who require urgent surgery for pathological vertebral fracture.

METHODS

The authors reviewed a prospectively collected database of all patients who underwent surgery with the senior author at their main hospital between June 1, 1998, and June 30, 2020. Patients admitted from the emergency room or after transfer from another hospital who then underwent surgery for pathological fracture during the same admission were included in the final analysis. Patients scheduled for elective surgery and those with previous cancer diagnoses were excluded.

RESULTS

Forty-three patients were identified as having undergone urgent surgical decompression and/or stabilization for pathological fracture. Histopathology confirmed diagnosis of MM in 22 (51%) patients, lung metastasis in 5 (12%) patients, and breast metastasis in 4 (9%) patients. Twelve (28%) patients were diagnosed with other types of metastatic carcinoma or undifferentiated disease. Sixteen of 29 (55%) men and 6 of 14 (42%) women were diagnosed with MM (p = 0.02). Seventeen of 34 (50%) patients who underwent surgery for neurological deficit, 5 of 6 (83%) patients who underwent surgery for spinal instability, and 0 (0%) patients who underwent surgery for pain with impending spinal cord injury were diagnosed with MM (p = 0.12).

CONCLUSIONS

A majority of patients presenting to the authors' hospital with no history of malignancy who required urgent surgery for pathological compression fracture were found to have MM or plasmacytoma. This disease process may affect a significant portion of patients requiring decompressive or stabilizing surgery for compression fracture in academic medical centers.

The Focused Neurosurgical Examination During Telehealth Visits: Guidelines During the COVID-19 Pandemic and Beyond

OBJECTIVE

 To provide guidelines to healthcare workers for performing a focused neurological examination via telemedicine during the coronavirus disease-2019 (COVID-2019) pandemic.

METHODS

 We reviewed our department's outpatient clinic visits after the implementation of a telemedicine protocol in response to the COVID-19 crisis. Crossover rates from telehealth to in-person visits were evaluated and guidelines for performing a telemedicine neurological exam were created based on the consensus of 16 neurosurgical attending providers over a four-month period.

RESULTS

 From March 23, 2020 to July 20, 2020, some 2157 telehealth visits were performed in our department. Some 26 were converted to in-person visits by the provider request with the most cited reason for conversion being the need for a more detailed patient evaluation. Based on these experiences, we created a graphical tutorial to address the key components of the neurological exam with adaptations specific to the telehealth visit.

CONCLUSIONS

 In response to the global coronavirus pandemic, telemedicine has become an integral part of neurosurgeons' daily practice. Telemedicine failures remain low but primarily occur due to a need for more comprehensive evaluations. We provide guidelines for the neurosurgical exam during telehealth visits in an effort to assuage some of these issues.

A Connectomic Atlas of the Human Cerebrum-Chapter 11: Tractographic Description of the Inferior Longitudinal Fasciculus

In this supplement, we seek to show a comprehensive anatomic atlas of the human cerebrum demonstrating all 180 distinct regions comprising the cerebral cortex. The location, functional connectivity, and structural connectivity of these regions are outlined, and where possible a discussion is included of the functional significance of these areas. In this chapter, we specifically address regions integrating to form the inferior longitudinal fasciculus.

A Connectomic Atlas of the Human Cerebrum-Chapter 3: The Motor, Premotor, and Sensory Cortices

In this supplement, we build on work previously published under the Human Connectome Project. Specifically, we show a comprehensive anatomic atlas of the human cerebrum demonstrating all 180 distinct regions comprising the cerebral cortex. The location, functional connectivity, and structural connectivity of these regions are outlined, and where possible a discussion is included of the functional significance of these areas. In part 3, we specifically address regions relevant to the sensorimotor cortices.

A Connectomic Atlas of the Human Cerebrum-Chapter 13: Tractographic Description of the Inferior Fronto-Occipital Fasciculus

The inferior fronto-occipital fasciculus (IFOF) is a large white matter tract of the human cerebrum with functional connectivity associated with semantic language processing and goal-oriented behavior. However, little is known regarding the overall connectivity of this tract. Recently, the Human Connectome Project parcellated the human cortex into 180 distinct regions. In our other work, we have shown these various regions in relation to clinically applicable anatomy and function. Utilizing Diffusion Spectrum Magnetic Resonance Imaging tractography coupled with the human cortex parcellation data presented earlier in this supplement, we aim to describe the macro-connectome of the IFOF in relation to the linked parcellations present within the human cortex. The purpose of this study is to present this information in an indexed, illustrated, and tractographically aided series of figures and tables for anatomic and clinical reference.

A Connectomic Atlas of the Human Cerebrum-Chapter 12: Tractographic Description of the Middle Longitudinal Fasciculus

The middle longitudinal fasciculus (MdLF) is a small and somewhat controversial white matter tract of the human cerebrum, confined to the posterior superior temporal region from which it courses posteriorly to connect at the occipital-parietal interface. The tract appears to be involved in language processing as well as auditory organization and localization, while sub-serving other higher level cognitive functions that have yet to be fully elucidated. Little is known about the specific, interparcellation connections that integrate to form the MdLF. Utilizing diffusion spectrum magnetic resonance imaging tractography coupled with the human cortex parcellation data presented earlier in this supplement, we aim to describe the macro-connectome of the MdLF in relation to the linked parcellations present within the human cortex. The purpose of this study is to present this information in an indexed, illustrated, and tractographically aided series of figures and tables for anatomic and clinical reference.

A Connectomic Atlas of the Human Cerebrum-Chapter 4: The Medial Frontal Lobe, Anterior Cingulate Gyrus, and Orbitofrontal Cortex

In this supplement, we build on work previously published under the Human Connectome Project. Specifically, we show a comprehensive anatomic atlas of the human cerebrum demonstrating all 180 distinct regions comprising the cerebral cortex. The location, functional connectivity, and structural connectivity of these regions are outlined, and where possible a discussion is included of the functional significance of these areas. In part 4, we specifically address regions relevant to the medial frontal lobe, anterior cingulate gyrus, and orbitofrontal cortex.

A Connectomic Atlas of the Human Cerebrum-Chapter 7: The Lateral Parietal Lobe

In this supplement, we build on work previously published under the Human Connectome Project. Specifically, we seek to show a comprehensive anatomic atlas of the human cerebrum demonstrating all 180 distinct regions comprising the cerebral cortex. The location, functional connectivity, and structural connectivity of these regions are outlined, and where possible a discussion is included of the functional significance of these areas. In part 7, we specifically address regions relevant to the lateral parietal lobe.

A Connectomic Atlas of the Human Cerebrum-Chapter 17: Tractographic Description of the Cingulum

In this supplement, we show a comprehensive anatomic atlas of the human cerebrum demonstrating all 180 distinct regions comprising the cerebral cortex. The location, functional connectivity, and structural connectivity of these regions are outlined, and where possible a discussion is included of the functional significance of these areas. In this chapter, we specifically address regions integrating to form the cingulum.

A Connectomic Atlas of the Human Cerebrum-Chapter 8: The Posterior Cingulate Cortex, Medial Parietal Lobe, and Parieto-Occipital Sulcus

In this supplement, we build on work previously published under the Human Connectome Project. Specifically, we seek to show a comprehensive anatomic atlas of the human cerebrum demonstrating all 180 distinct regions comprising the cerebral cortex. The location, functional connectivity, and structural connectivity of these regions are outlined, and where possible a discussion is included of the functional significance of these areas. In part 8, we specifically address regions relevant to the posterior cingulate cortex, medial parietal lobe, and the parieto-occipital sulcus.

A Connectomic Atlas of the Human Cerebrum-Chapter 5: The Insula and Opercular Cortex

In this supplement, we build on work previously published under the Human Connectome Project. Specifically, we show a comprehensive anatomic atlas of the human cerebrum demonstrating all 180 distinct regions comprising the cerebral cortex. The location, functional connectivity, and structural connectivity of these regions are outlined, and where possible a discussion is included of the functional significance of these areas. In part 5, we specifically address regions relevant to the insula and opercular cortex.

A Connectomic Atlas of the Human Cerebrum-Chapter 6: The Temporal Lobe

In this supplement, we build on work previously published under the Human Connectome Project. Specifically, we show a comprehensive anatomic atlas of the human cerebrum demonstrating all 180 distinct regions comprising the cerebral cortex. The location, functional connectivity, and structural connectivity of these regions are outlined, and where possible a discussion is included of the functional significance of these areas. In part 6, we specifically address regions relevant to the temporal lobe.

A Connectomic Atlas of the Human Cerebrum-Chapter 10: Tractographic Description of the Superior Longitudinal Fasciculus

The superior longitudinal fasciculus/arcuate white matter complex (SLF/AC) is the largest and most complex white matter tract of the human cerebrum with multiple inter-linked connections encompassing multiple cognitive functions such as language, attention, memory, emotion, and visuospatial function. However, little is known regarding the overall connectivity of this complex. Recently, the Human Connectome Project parcellated the human cortex into 180 distinct regions. Utilizing diffusion spectrum magnetic resonance imaging tractography coupled with the human cortex parcellation data presented earlier in this supplement, we aim to describe the macro-connectome of the SLF/AC in relation to the linked parcellations present within the human cortex. The purpose of this study is to present this information in an indexed, illustrated, and tractographically aided series of figures and tables for anatomic and clinical reference.

A Connectomic Atlas of the Human Cerebrum-Chapter 2: The Lateral Frontal Lobe

In this supplement, we show a comprehensive anatomic atlas of the human cerebrum demonstrating all 180 distinct regions comprising the cerebral cortex. The location, functional connectivity, and structural connectivity of these regions are outlined, and where possible a discussion is included of the functional significance of these areas. In part 2, we specifically address regions relevant to the lateral frontal lobe.

A Connectomic Atlas of the Human Cerebrum-Chapter 16: Tractographic Description of the Vertical Occipital Fasciculus

In this supplement, we show a comprehensive anatomic atlas of the human cerebrum demonstrating all 180 distinct regions comprising the cerebral cortex. The location, functional connectivity, and structural connectivity of these regions are outlined, and where possible a discussion is included of the functional significance of these areas. In this chapter, we specifically address regions integrating to form the vertical occipital fasciculus.

A Connectomic Atlas of the Human Cerebrum-Chapter 14: Tractographic Description of the Frontal Aslant Tract

In this supplement, we show a comprehensive anatomic atlas of the human cerebrum demonstrating all 180 distinct regions comprising the cerebral cortex. The location, functional connectivity, and structural connectivity of these regions are outlined, and where possible a discussion is included of the functional significance of these areas. In this chapter, we specifically address the regions integrating to form the frontal aslant tract.

A Connectomic Atlas of the Human Cerebrum-Chapter 15: Tractographic Description of the Uncinate Fasciculus

In this supplement, we show a comprehensive anatomic atlas of the human cerebrum demonstrating all 180 distinct regions comprising the cerebral cortex. The location, functional connectivity, and structural connectivity of these regions are outlined, and where possible a discussion is included of the functional significance of these areas. In this chapter, we specifically address the regions integrating to form the uncinate fasciculus.

A Connectomic Atlas of the Human Cerebrum-Chapter 1: Introduction, Methods, and Significance

BACKGROUND

As knowledge of the brain has increased, clinicians have learned that the cerebrum is composed of complex networks that interact to execute key functions. While neurosurgeons can typically predict and preserve primary cortical function through the primary visual and motor cortices, preservation of higher cognitive functions that are less well localized in regions previously deemed "silent" has proven more difficult. This suggests these silent cortical regions are more anatomically complex and redundant than our previous methods of inquiry can explain, and that progress in cerebral surgery will be made with an improved understanding of brain connectomics. Newly published parcellated cortex maps provide one avenue to study such connectomics in greater detail, and they provide a superior framework and nomenclature for studying cerebral function and anatomy.

OBJECTIVE

To describe the structural and functional aspects of the 180 distinct areas that comprise the human cortex model previously published under the Human Connectome Project (HCP).

METHODS

We divided the cerebrum into 8 macroregions: lateral frontal, motor/premotor, medial frontal, insular, temporal, lateral parietal, medial parietal, and occipital. These regions were further subdivided into their relevant parcellations based on the HCP cortical scheme. Connectome Workbench was used to localize parcellations anatomically and to demonstrate their functional connectivity. DSI studio was used to assess the structural connectivity for each parcellation.

RESULTS

The anatomy, functional connectivity, and structural connectivity of all 180 cortical parcellations identified in the HCP are compiled into a single atlas. Within each section of the atlas, we integrate this information, along with what is known about parcellation function to summarize the implications of these data on network connectivity.

CONCLUSION

This multipart supplement aims to build on the work of the HCP. We present this information in the hope that the complexity of cerebral connectomics will be conveyed in a more manageable format that will allow neurosurgeons and neuroscientists to accurately communicate and formulate hypotheses regarding cerebral anatomy and connectivity. We believe access to this information may provide a foundation for improving surgical outcomes by preserving lesser-known networks.

Parcellation-based tractographic modeling of the dorsal attention network

INTRODUCTION

The dorsal attention network (DAN) is an important mediator of goal-directed attentional processing. Multiple cortical areas, such as the frontal eye fields, intraparietal sulcus, superior parietal lobule, and visual cortex, have been linked in this processing. However, knowledge of network connectivity has been devoid of structural specificity.

METHODS

Using attention-related task-based fMRI studies, an anatomic likelihood estimation (ALE) of the DAN was generated. Regions of interest corresponding to the cortical parcellation scheme previously published under the Human Connectome Project were co-registered onto the ALE in MNI coordinate space and visually assessed for inclusion in the network. DSI-based fiber tractography was performed to determine the structural connections between relevant cortical areas comprising the network.

RESULTS

Twelve cortical regions were found to be part of the DAN: 6a, 7AM, 7PC, AIP, FEF, LIPd, LIPv, MST, MT, PH, V4t, VIP. All regions demonstrated consistent u-shaped interconnections between adjacent parcellations. The superior longitudinal fasciculus connects the frontal, parietal, and occipital areas of the network.

CONCLUSIONS

We present a tractographic model of the DAN. This model comprises parcellations within the frontal, parietal, and occipital cortices principally linked through the superior longitudinal fasciculus. Future studies may refine this model with the ultimate goal of clinical application.

Blunt vertebral artery injury in occipital condyle fractures

OBJECTIVEA shifting emphasis on efficient utilization of hospital resources has been seen in recent years. However, reduced screening for blunt vertebral artery injury (BVAI) may result in missed diagnoses if risk factors are not fully understood. The authors examined the records of blunt trauma patients with fractures near the craniocervical junction who underwent CTA at a single institution to better understand the risk of BVAI imposed by occipital condyle fractures (OCFs).METHODSThe authors began with a query of their prospectively collected trauma registry to identify patients who had been screened for BVAI using ICD-9-CM diagnostic codes. Grade and segment were recorded in instances of BVAI. Locations of fractures were classified into 3 groups: 1) OCFs, 2) C1 (atlas) fractures, and 3) fractures of the C2-6 vertebrae. Univariate and multivariate analyses were performed to identify any fracture types associated with BVAI.RESULTSDuring a 6-year period, 719 patients underwent head and neck CTA following blunt trauma. Of these patients, 147 (20%) had OCF. BVAI occurred in 2 of 43 patients with type I OCF, 1 of 42 with type II OCF, and in 9 of 62 with type III OCF (p = 0.12). Type III OCF was an independent risk factor for BVAI in multivariate modeling (OR 2.29 [95% CI 1.04-5.04]), as were fractures of C1-6 (OR 5.51 [95% CI 2.57-11.83]). Injury to the V4 segment was associated with type III OCF (p < 0.01).CONCLUSIONSIn this study, the authors found an association between type III OCF and BVAI. While further study may be necessary to elucidate the mechanism of injury in these cases, this association suggests that thorough cerebrovascular evaluation is warranted in patients with type III OCF.

Imaging characteristics of chronic spinal cord injury identified during screening for a cell transplantation clinical trial

OBJECTIVE

In cell transplantation trials for spinal cord injury (SCI), quantifiable imaging criteria that serve as inclusion criteria are important in trial design. The authors’ institutional experience has demonstrated an overall high rate of screen failures. The authors examined the causes for trial exclusion in a phase I, open-lab clinical trial examining the role of autologous Schwann cell intramedullary transplantation. Specifically, they reviewed the imaging characteristics in people with chronic SCI that excluded applicants from the trial, as this was a common cause of screening failures in their study.

METHODS

The authors reviewed MRI records from 152 people with chronic (> 1 year) SCI who volunteered for intralesional Schwann cell transplantation but were deemed ineligible by prospectively defined criteria. Rostral-caudal injury lesion length was measured along the long axis of the spinal cord in the sagittal plane on T2-weighted MRI. Other lesion characteristics, specifically those pertaining to lesion cavity structure resulting in trial exclusion, were recorded.

RESULTS

Imaging records from 152 potential participants with chronic SCI were reviewed, 42 with thoracic-level SCI and 110 with cervical-level SCI. Twenty-three individuals (55%) with thoracic SCI and 70 (64%) with cervical SCI were not enrolled in the trial based on imaging characteristics. For potential participants with thoracic injuries who did not meet the screening criteria for enrollment, the average rostral-caudal sagittal lesion length was 50 mm (SD 41 mm). In applicants with cervical injuries who did not meet the screening criteria for enrollment, the average sagittal lesion length was 34 mm (SD 21 mm).

CONCLUSIONS

While screening people with SCI for participation in a cell transplantation clinical trial, lesion length or volume can exclude potential subjects who appear appropriate candidates based on neurological eligibility criteria. In planning future cell-based therapy trials, the limitations incurred by lesion size should be considered early due to the screening burden and impact on candidate selection.

A Connectomic Atlas of the Human Cerebrum-Chapter 18: The Connectional Anatomy of Human Brain Networks

BACKGROUND

It is widely understood that cortical functions are mediated by complex, interdependent brain networks. These networks have been identified and studied using novel technologies such as functional magnetic resonance imaging under both resting-state and task-based conditions. However, no one has attempted to describe these networks in terms of their cortical parcellations.

OBJECTIVE

To describe our approach to network modeling and discuss its significance for the future of neuronavigation in brain surgery using the cortical parcellation scheme detailed within this supplement.

METHODS

Using network models previously elucidated by our group using coordinate-based meta-analytic techniques, we show the anatomic position and underlying white matter tracts of the cortical regions comprising 8 functional networks of the human cerebrum. These network models are displayed using Synaptive's clinically available BrightMatter tractography software (Synaptive Medical, Toronto, Canada).

RESULTS

The relevant cortical parcellations of 8 different cerebral networks have been identified. The fiber tracts between these regions were used to construct anatomically precise models of the networks. Models are described for the dorsal attention, ventral attention, semantic, auditory, supplementary motor, ventral premotor, default mode, and salience networks.

CONCLUSION

Our goal is to move towards more precise, anatomically specific models of brain networks that can be constructed for individual patients and utilized in navigational platforms during brain surgery. We believe network modeling and future advances in navigation technology can provide a foundation for improving neurosurgical outcomes by allowing us to preserve complex brain networks.

A Connectomic Atlas of the Human Cerebrum-Chapter 9: The Occipital Lobe

In this supplement, we build on work previously published under the Human Connectome Project. Specifically, we seek to show a comprehensive anatomic atlas of the human cerebrum demonstrating all 180 distinct regions comprising the cerebral cortex. The location, functional connectivity, and structural connectivity of these regions are outlined, and where possible a discussion is included of the functional significance of these areas. In part 9, we specifically address regions relevant to the occipital lobe and the visual system.

Anatomy and white matter connections of the orbitofrontal gyrus

OBJECTIVE

The orbitofrontal cortex (OFC) is understood to have a role in outcome evaluation and risk assessment and is commonly involved with infiltrative tumors. A detailed understanding of the exact location and nature of associated white matter tracts could significantly improve postoperative morbidity related to declining capacity. Through diffusion tensor imaging–based fiber tracking validated by gross anatomical dissection as ground truth, the authors have characterized these connections based on relationships to other well-known structures.

METHODS

Diffusion imaging from the Human Connectome Project for 10 healthy adult controls was used for tractography analysis. The OFC was evaluated as a whole based on connectivity with other regions. All OFC tracts were mapped in both hemispheres, and a lateralization index was calculated with resultant tract volumes. Ten postmortem dissections were then performed using a modified Klingler technique to demonstrate the location of major tracts.

RESULTS

The authors identified 3 major connections of the OFC: a bundle to the thalamus and anterior cingulate gyrus, passing inferior to the caudate and medial to the vertical fibers of the thalamic projections; a bundle to the brainstem, traveling lateral to the caudate and medial to the internal capsule; and radiations to the parietal and occipital lobes traveling with the inferior fronto-occipital fasciculus.

CONCLUSIONS

The OFC is an important center for processing visual, spatial, and emotional information. Subtle differences in executive functioning following surgery for frontal lobe tumors may be better understood in the context of the fiber-bundle anatomy highlighted by this study.

Method for temporal keyhole lobectomies in resection of low- and high-grade gliomas

OBJECTIVE

The purpose of this study was to describe a method of resecting temporal gliomas through a keyhole lobectomy and to share the results of using this technique.

METHODS

The authors performed a retrospective review of data obtained in all patients in whom the senior author performed resection of temporal gliomas between 2012 and 2015. The authors describe their technique for resecting dominant and nondominant gliomas, using both awake and asleep keyhole craniotomy techniques.

RESULTS

Fifty-two patients were included in the study. Twenty-six patients (50%) had not received prior surgery. Seventeen patients (33%) were diagnosed with WHO Grade II/III tumors, and 35 patients (67%) were diagnosed with a glioblastoma. Thirty tumors were left sided (58%). Thirty procedures (58%) were performed while the patient was awake. The median extent of resection was 95%, and at least 90% of the tumor was resected in 35 cases (67%). Five of 49 patients (10%) with clinical follow-up experienced permanent deficits, including 3 patients (6%) with hydrocephalus requiring placement of a ventriculoperitoneal shunt and 2 patients (4%) with weakness. Three patients experienced early postoperative anomia, but no patients had a new speech deficit at clinical follow-up.

CONCLUSIONS

The authors provide their experience using a keyhole lobectomy for resecting temporal gliomas. Their data demonstrate the feasibility of using less invasive techniques to safely and aggressively treat these tumors.

Dural Closure in Confined Spaces of the Skull Base with Nonpenetrating Titanium Clips

BACKGROUND

Dural repair in areas with limited operative maneuverability has long been a challenge in skull base surgery. Without adequate dural closure, postoperative complications, including cerebrospinal fluid (CSF) leak and infection, can occur.

OBJECTIVE

To show a novel method by which nonpenetrating, nonmagnetic titanium microclips can be used to repair dural defects in areas with limited operative access along the skull base.

METHODS

We reviewed 53 consecutive surgical patients in whom a dural repair technique utilizing titanium microclips was performed from 2013 to 2016 at our institution. The repairs primarily involved difficult-to-reach dural defects in which primary suturing was difficult or impractical. A detailed surgical technique is described in 3 selected cases involving the anterior, middle, and posterior fossae, respectively. An additional 5 cases are provided in more limited detail to demonstrate clip artifact on postoperative imaging. Rates of postoperative CSF leak and other complications are reported.

RESULTS

The microclip technique was performed successfully in 53 patients. The most common pathology in this cohort was skull base meningioma (32/53). Additional surgical indications included traumatic dural lacerations (9/53), nonmeningioma tumors (8/53), and other pathologies (4/53). The clip artifact present on postoperative imaging was minor and did not interfere with imaging interpretation. CSF leak occurred postoperatively in 3 (6%) patients. No obvious complications attributable to microclip usage were encountered.

CONCLUSION

In our experience, intracranial dural closure with nonpenetrating, nonmagnetic titanium microclips is a feasible adjunct to traditional methods of dural repair.

Contemporaneous biopsy and laser interstitial thermal therapy for two treatment-refractory brain metastases

Recurrent treatment-refractory brain metastases can be treated with modern adjuvant therapies such as laser interstitial thermal therapy (LITT). Since previously radiated lesions may be indolent (treatment effect) or recurrent tumor, histological confirmation may be helpful. The authors present the utility of contemporaneous biopsy and LITT using intraoperative O-arm navigation in a patient who presented with multiple refractory metastases. The authors demonstrate the utility of O-arm navigation to confirm intraoperative biopsy and LITT placement. Concurrent stereotactic biopsy and LITT may be a safe and efficacious method for both the diagnosis and treatment of deep lesions that are unamenable to standard adjuvant treatment modalities.

The video can be found here: https://youtu.be/SUY-qiahMyo.