Brian M. Howard

Endoscopic endonasal transsphenoidal surgery using a skull reference array and laser surface scanning.

Lesions of the skull base are increasingly being resected via the endoscopic, endonasal, transphenoidal approach. We have successfully treated 33 consecutive patients with pituitary lesions using this technique in combination with BrainLAB skull reference array and laser surface scanning for surgical navigation. This technique affords several advantages over neuronavigation based on adhesive-mounted fiducial registration. Rigid fixation in a Mayfield clamp is not required, which allows for flexibility with respect to positioning of the head during the procedure. This is particularly important as extension and flexion of the head provide greater exposure to the clivus and anterior skull base respectively. Also, this technique obviates the need for additional preoperative MRI, thereby reducing cost and delays.

Interhospital Transfer of Neurosurgical Patients to a High-Volume Tertiary Care Center: Opportunities for Improvement.

BACKGROUND Neurosurgical indications for patient transfer include absence of local or available neurosurgical coverage, subspecialty or interdisciplinary requirements, and family preference. Transfer of patients to regional centers will increase with further centralization of medical care. OBJECTIVE To report the transfer records of a large tertiary care center to identify trends, failures, and opportunities to improve interhospital transfer of neurosurgical patients. METHODS All consecutive, prospectively documented requests for interhospital patient transfer to the adult neurosurgical service of Emory University Hospitals were retrospectively identified from a centralized transfer center database for a 1-year study period. RESULTS Requests for neurosurgical care constituted 1323 of the 9087 calls (14.6%); 81.1% of these requests were accepted, and a total of 984 patients (74.4%) arrived at our institutions. Patients arrived from 133 unique facilities throughout a catchment area of 66 287 sq miles. Although the median travel time for transfer patients was 36 minutes, the median interval between the request and patient arrival was 4 hours 2 minutes. The most frequent diagnoses were intracranial hemorrhage (31.8%), subarachnoid hemorrhage (31.2%), and intracranial tumor (15.2%). The overall diagnostic error rate was 10.3%. Only 42.5% of patients underwent neurosurgical intervention, and 57 patients admitted to intensive care were immediately transitioned to a lower level of care. CONCLUSION Interhospital transfer requires a coordinated effort among hospital administrators, physicians, and staff to make complex decisions that govern this important and costly process. These data suggest common failures and numerous opportunities for improvement in transfer efficiency, diagnostic accuracy, triage, and resource allocation.

Utility of surveillance imaging after minor blunt head trauma.

OBJECT Nonoperative blunt head trauma is a common reason for admission in a pediatric hospital. Adverse events, such as growing skull fracture, are rare, and the incidence of such morbidity is not known. As a result, optimal follow-up care is not clear. METHODS Patients admitted after minor blunt head trauma between May 1, 2009, and April 30, 2013, were identified at a single institution. Demographic, socioeconomic, and clinical characteristics were retrieved from administrative and outpatient databases. Clinical events within the 180-day period following discharge were reviewed and analyzed. These events included emergency department (ED) visits, need for surgical procedures, clinic visits, and surveillance imaging utilization. Associations among these clinical events and potential contributing factors were analyzed using appropriate statistical methods. RESULTS There were 937 admissions for minor blunt head trauma in the 4-year period. Patients who required surgical interventions during the index admission were excluded. The average age of the admitted patients was 5.53 years, and the average length of stay was 1.7 days; 15.7% of patients were admitted for concussion symptoms with negative imaging findings, and 26.4% of patients suffered a skull fracture without intracranial injury. Patients presented with subdural, subarachnoid, or intraventricular hemorrhage in 11.6%, 9.19%, and 0.53% of cases, respectively. After discharge, 672 patients returned for at least 1 follow-up clinic visit (71.7%), and surveillance imaging was obtained at the time of the visit in 343 instances. The number of adverse events was small and consisted of 34 ED visits and 3 surgeries. Some of the ED visits could have been prevented with better discharge instructions, but none of the surgery was preventable. Furthermore, the pattern of postinjury surveillance imaging utilization correlated with physician identity but not with injury severity. Because the number of adverse events was small, surveillance imaging could not be shown to positively influence outcomes. CONCLUSIONS Adverse events after nonoperative mild traumatic injury are rare. The routine use of postinjury surveillance imaging remains controversial, but these data suggest that such imaging does not effectively identify those who require operative intervention.

Carotid cavernous fistula after Pipeline placement: a single-center experience and review of the literature

Objective Carotid cavernous fistula (CCF) development after Pipeline Embolization Device (PED) treatment of cavernous carotid aneurysms (CCA) can be a challenging pathology to treat for the neurointerventionalist. Methods A database of all patients whose aneurysms were treated with the PED since its approval by the Food and Drug Administration in 2011 was retrospectively reviewed. Demographic information, aneurysm characteristics, treatment technique, antiplatelet regimen, and follow-up data were collected. A literature review of all papers that describe PED treatment of CCA was then completed. Results A total of 44 patients with 45 CCAs were identified (38 women, 6 men). The mean age was 59.9±9.0 years. The mean maximal aneurysm diameter was 15.9±6.9 mm (mean neck 7.1±3.6 mm). A single PED was deployed in 32 patients, with two PEDs deployed in 10 patients and three PEDs in 3 patients. Adjunctive coiling was performed in 3 patients. Mean follow-up duration based on final imaging (MR angiography or digital subtraction angiography) was 14.1±12.2 months. Five patients (11.4%) developed CCFs in the post-procedural period after PED treatment, all within 2 weeks of device placement. These CCFs were treated with a balloon test occlusion followed by parent artery sacrifice. Our literature review yielded only three reports of CCFs after PED placement, with the largest series having a CCF rate of 2.3%. Conclusions CCF formation is a known risk of PED treatment of CCA. Although transvenous embolization can be used for treating CCFs, parent artery sacrifice remains a viable option on the basis of these data. Studies support the view that adjunctive coiling may have a protective effect against post-PED CCF formation. None of the coiled aneurysms in our database or in the literature have ruptured. Follow-up data will lead to a better understanding of the safety profile of the PED for CCA.

Outcomes for Patients with Poor-Grade Subarachnoid Hemorrhage: To Treat or Not To Treat?

neurysmal subarachnoid hemorrhage (aSAH) is a potentially devastating condition that confers high rates of A morbidity and mortality. Although mortality from aSAH has decreased significantly over the past several decades, current estimates of case fatality in the United States and Western Europe remain as high as 40% for all patients. Improvements in microsurgical and endovascular techniques, coupled with the development of neurocritical care as a distinct discipline, have contributed to the steady decline in overall morbidity and mortality from aSAH. Although outcomes have improved, aSAH continues to account for almost 30% of stroke-related years of potential life lost before age 65 despite being responsible for only 4.4% of all stroke-related mortality. Survivors of aSAH not only suffer from increased all-cause mortality, but also from significant morbidity well after recovery from the acute phase of illness. Studies indicate functional dependence in approximately 20% of survivors.

Reduced Efficacy of the Pipeline Embolization Device in the Treatment of Posterior Communicating Region Aneurysms with Fetal Posterior Cerebral Artery Configuration

BACKGROUND Aneurysms at the origin of the posterior communicating artery (PcommA) have been demonstrated to be effectively treated with the pipeline embolization device (PED). Much less is known about the efficacy of the PED for aneurysms associated with a fetal posterior cerebral artery (fPCA) variant. OBJECTIVE To study PED treatment efficacy of PcommA aneurysms, including fPCA aneurysms. METHODS A prospectively maintained university database of aneurysm patients treated with the PED was retrospectively reviewed. Demographics, treatment details, and imaging were reviewed for all PcommA and fPCA aneurysms. RESULTS Out of a total of 285 patients treated with PED, 50 patients (mean age 57.5 ± 12.2 yr, 42 females) with unruptured PcommA (9 fPCA) aneurysms were identified. Mean follow-up duration was 14.0 ± 11.6 mo (48 patients). Roy-Raymond class I occlusion on follow-up magnetic resonance or catheter angiography (mean time 11.7 ± 6.8 mo) was achieved in 30 patients (62.5%), class II occlusion in 11 patients (22.9%) and class III occlusion in 7 patients (14.5%). The PcommA was occluded in 56% of patients without any clinical symptoms. No deaths or permanent neurological complications occurred. In fPCA aneurysms, class I occlusion was seen in 1 patient, class 2 occlusion in 2 patients, and class III occlusion in 6 patients. Multivariate analysis revealed an independent association between incomplete occlusion and fPCA configuration (OR 73.65; 95% CI: 5.84-929.13; P = .001). CONCLUSION The PED is a safe and effective treatment for PcommA aneurysms, although fetal anatomy should increase consideration of traditional endovascular techniques or surgical clipping.

Association of Overlapping Surgery With Patient Outcomes in a Large Series of Neurosurgical Cases

Importance Overlapping surgery (OS) is common. However, there is a dearth of evidence to support or refute the safety of this practice. Objective To determine whether OS is associated with worsened morbidity and mortality in a large series of neurosurgical cases. Design, Setting, and Participants A retrospective cohort study was completed for patients who underwent neurosurgical procedures at Emory University Hospital, a large academic referral hospital, between January 1, 2014, and December 31, 2015. Patients were operated on for pathologies across the spectrum of neurosurgical disorders. Propensity score weighting and logistic regression models were executed to compare outcomes for patients who received nonoverlapping surgery and OS. Investigators were blinded to study cohorts during data collection and analysis. Main Outcomes and Measures The primary outcome measures were 90-day postoperative mortality, morbidity, and functional status. Results In this cohort of 2275 patients who underwent neurosurgery, 1259 (55.3%) were female, and the mean (SD) age was 52.1 (16.4) years. A total of 972 surgeries (42.7%) were nonoverlapping while 1303 (57.3%) were overlapping. The distribution of American Society of Anesthesiologists score was similar between nonoverlapping surgery and OS cohorts. Median surgical times were significantly longer for patients in the OS cohort vs the nonoverlapping surgery cohort (in-room time, 219 vs 188 minutes; skin-to-skin time, 141 vs 113 minutes; both P < .001). Overlapping surgery was more frequently elective (93% vs 87%; P < .001). Regression analysis failed to demonstrate an association between OS and complications, such as mortality, morbidity, or worsened functional status. Measures of baseline severity of illness, such as admission to the intensive care unit and increased length of stay, were associated with mortality (intensive care unit: odds ratio [OR], 25.5; 95% CI, 6.22-104.67; length of stay: OR, 1.03; 95% CI, 1.00-1.05), morbidity (intensive care unit: OR, 1.85; 95% CI, 1.43-2.40; length of stay: OR, 1.06; 95% CI, 1.04-1.08), and unfavorable functional status (length of stay: OR, 1.03; 95% CI, 1.02-1.05). Conclusions and Relevance These data suggest that OS can be safely performed if appropriate precautions and patient selection are followed. Data such as these will help determine health care policy to maximize patient safety.

Spinal Vascular Malformations

This chapter discusses the various aspects of spinal vascular malformations. Vascular malformations of the spinal cord are a heterogeneous group of anomalies ranging from simple, dural arteriovenous fistulae to complex arteriovenous malformations that may involve the spinal cord parenchyma as well as adjacent spinal and extraspinal structures. Most spinal vascular malformations can be classified into one of four types that differ significantly in etiology, anatomy, pathophysiology, radiological appearance, and treatment. Type I spinal arteriovenous malformations (AVMs) have two or more arterial feeders that enter at separate segmental levels. In this situation, the additional segmental dural branches travel within the dura to the fistula nidus where they converge to communicate with the efferent vein. Type II spinal cord AVMs are also referred to as glomus malformations and consist of intramedullary vascular malformations that have a true compact nidus within the parenchyma of the spinal cord. Type I spinal AVMs are believed to be acquired lesions although the mechanism for their development is not understood. These malformations cause symptoms primarily though venous hypertension. The surgical treatment of these lesions is very straightforward and outcome is most dependent on the patients condition at the time of diagnosis. The availability of magnetic resonance imaging has made the diagnosis much simpler but high quality spinal angiography is still necessary to establish the diagnosis, classify the lesion, and plan appropriate treatment, whether it is endovascular, surgical, or a combination.

Neurological outcomes following iatrogenic vascular injury during posterior atlanto-axial instrumentation.

BACKGROUND Iatrogenic vascular injury is a feared complication of posterior atlanto-axial instrumentation. A better understanding of clinical outcome and management options following this injury will allow surgeons to better care for these patients. The object of the study was to systematically review the neurologic outcomes after iatrogenic vascular injury during atlanto-axial posterior instrumentation. METHODS We performed a systematic review of the Medline database following PRISMA guidelines. In our analysis, we included any retrospective cohort studies, prospective cohort studies, case reports, cases series, or systematic reviews with patients who had undergone posterior atlanto-axial fusion via screw rod constructs (SRC) or transarticular screws (TAS) that reported a patient with an injury to an arterial vessel directly attributable to the surgical procedure. RESULTS Sixty cases of vascular injury were reported in 2078 (2.9%) patients over 27 publications. The average age for this patient population was 55.7+/-17.9. Vascular injury following posterior C1/2 instrumentation resulted in ipsilateral stroke in 10.0% (n=6/60) and non-persistent neurologic deficit in 6.7% (n=4/60) of cases with the deficit being permanent (not including death) in 1.7% (n=1/60) of cases. Four patients (6.7%) died. Arteriovenous fistula or pseudoaneurysm occurred in 8.3% (n=5/60) and 3.3% (n=2/60) of cases, respectively. Eight patients (13.3%) underwent endovascular repair of the injury with no permanent deficit. CONCLUSION Neurological morbidity after iatrogenic vascular injury during posterior C1/2 fixation is higher than previously reported in literature. Some patients may benefit from endovascular treatment. Surgeons should be aware of normal and anomalous vertebral artery anatomy to avoid this potentially catastrophic complication.

Thoracic lateral extracavitary corpectomy for anterior column reconstruction with expandable and static titanium cages: Clinical outcomes and surgical considerations in a consecutive case series

OBJECTIVE Many surgical interventions have emerged as effective means of restoring mechanical stability of the anterior column of the spine. The lateral extracavitary approach (LECA) allows for broad visualization and circumferential reconstruction of the spinal column. However, early reports demonstrated significant complication rates, protracted operative times, and prolonged hospitalizations. More recent reports have highlighted concerns for subsidence, particularly with expandable cages. Our work seeks to describe a single-surgeon consecutive series of patients undergoing LECA for thoracic corpectomy. Specifically, the objective was to explore the surgical considerations, clinical and radiographic outcomes, and complication profile of this approach. METHODS A retrospective study examined data from 17 consecutive patients in whom single or multi-level corpectomy was performed via a LECA by a single surgeon. Vertebral body replacement was achieved with either a static or expandable titanium cage. The Karnofsky Performance Scale (KPS) was utilized to assess patient functional status before and after surgery. Radiographic outcomes, particularly footplate-to-body ratio and subsidence, were assessed on CT imaging at 6 weeks after surgery and at follow-up of at least 6 months. RESULTS The majority of patients had post-operative KPS scores consistent with functional independence (≥70, 12/17 patients, 71%). Fourteen patients had improved or maintained function by last follow-up. In both groups, all patients had a favorable footplate-to-body ratio, and rates of subsidence were similar at both time points. Notably, the overall complication rate (24%) was significantly lower than that published in the literature, and no patient suffered a pneumothorax that required placement of a thoracostomy tube. CONCLUSION The LECA approach for anterior column reconstruction with static or expandable cages is an important surgical consideration with favorable surgical parameters and complication rates. Further, use of expandable cages may allow for reconstruction over a larger segment without increased risk of subsidence.