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Michael A. Silva, Alfred P. See, Hormuzdiyar H. Dasenbrock, Nirav J. Patel, and Mohammad A. Aziz-Sultan

OBJECTIVE

Patients with paraclinoid aneurysms commonly present with visual impairment. They have traditionally been treated with clipping or coiling, but flow diversion (FD) has recently been introduced as an alternative treatment modality. Although there is still initial aneurysm thrombosis, FD is hypothesized to reduce mass effect, which may decompress the optic nerve when treating patients with visually symptomatic paraclinoid aneurysms. The authors performed a meta-analysis to compare vision outcomes following clipping, coiling, or FD of paraclinoid aneurysms in patients who presented with visual impairment.

METHODS

A systematic literature review was performed using the PubMed and Web of Science databases. Studies published in English between 1980 and 2016 were included if they reported preoperative and postoperative visual function in at least 5 patients with visually symptomatic paraclinoid aneurysms (cavernous segment through ophthalmic segment) treated with clipping, coiling, or FD. Neuroophthalmological assessment was used when reported, but subjective patient reports or objective visual examination findings were also acceptable.

RESULTS

Thirty-nine studies that included a total of 2458 patients (520 of whom presented with visual symptoms) met the inclusion criteria, including 307 visually symptomatic cases treated with clipping (mean follow-up 26 months), 149 treated with coiling (mean follow-up 17 months), and 64 treated with FD (mean follow-up 11 months). Postoperative vision in these patients was classified as improved, unchanged, or worsened compared with preoperative vision. A pooled analysis showed preoperative visual symptoms in 38% (95% CI 28%–50%) of patients with paraclinoid aneurysms. The authors found that vision improved in 58% (95% CI 48%–68%) of patients after clipping, 49% (95% CI 38%–59%) after coiling, and 71% (95% CI 55%–84%) after FD. Vision worsened in 11% (95% CI 7%–17%) of patients after clipping, 9% (95% CI 2%–18%) after coiling, and 5% (95% CI 0%–20%) after FD. New visual deficits were found in patients with intact baseline vision at a rate of 1% (95% CI 0%–3%) for clipping, 0% (95% CI 0%–2%) for coiling, and 0% (95% CI 0%–2%) for FD.

CONCLUSIONS

To the authors’ knowledge, this is the first meta-analysis to assess vision outcomes after treatment for paraclinoid aneurysms. The authors found that 38% of patients with these aneurysms presented with visual impairment. These data also demonstrated a high rate of visual improvement after FD without a significant difference in the rate of worsened vision or iatrogenic visual impairment compared with clipping and coiling. These findings suggest that FD is an effective option for treatment of visually symptomatic paraclinoid aneurysms.

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Nickalus R. Khan, Victor M. Lu, Turki Elarjani, Michael A. Silva, Aria M. Jamshidi, Iahn Cajigas, and Jacques J. Morcos

OBJECTIVE

Cerebral extracranial-intracranial (EC-IC) direct bypass is a commonly used procedure for ischemic vasculopathy. A previously described variation of this technique is to utilize one donor artery to supply two recipient arteries, which the authors designate as 1D2R. The purpose of this study is to present a single surgeon’s series of 1D2R direct bypasses for moyamoya and ischemia using detailed clinical, angiographic, and intraoperative blood flow measurement data. To the authors’ knowledge, this is the largest series reported to date.

METHODS

Hospital, office, and radiographic imaging records for all patients who underwent cerebral revascularization using a 1D2R bypass by the senior author were reviewed. The patients’ demographic information, clinical presentation, associated medical conditions, intraoperative information, and postoperative course were obtained from reviewing the medical records.

RESULTS

A total of 21 1D2R bypasses were performed in 19 patients during the study period. Immediate bypass patency was 100% and was 90% on delayed follow-up. The mean initial cut flow index (CFI(i)) was 0.64 ± 0.33 prior to the second anastomosis and the mean final value (CFI(f)) was 0.94 ± 0.38 after the second anastomosis (p < 0.001). The overall bypass flow increased on average by 50% (mean 17.9 ml/min, range −10 to 40 ml/min) with the addition of the second anastomosis. There was no significant difference in the overall flow measurements when the end-to-side anastomosis or side-to-side anastomosis was performed first. There was a statistically significant difference in the proportion of patients with a modified Rankin Scale (mRS) score of 0 or 1 postoperatively compared to preoperatively (p < 0.01). Through the application of Poiseuille’s law, the authors analyzed flow dynamics, deduced the component vascular resistances based on an analogy to electrical circuits and Ohm’s law, and introduced the new concepts of “second anastomosis relative augmentation” and “second anastomosis sink index” in the evaluation of 1D2R bypasses.

CONCLUSIONS

The application of the 1D2R technique in a series of 19 consecutive patients undergoing direct EC-IC bypass for flow augmentation demonstrated high patency rates, statistically significantly higher CFIs compared to 1D1R, and improved mRS scores at last clinical follow-up. Additionally, the technique allows a shorter dissection time and preserves blood flow to the scalp. The routine utilization of intraoperative volumetric flow measurements in such surgeries allows a deeper understanding of the hemodynamic impact on individual patients.

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Nicole A. Silva, Belinda Shao, Michael J. Sylvester, Jean Anderson Eloy, and Chirag D. Gandhi

OBJECTIVE

Observation and neurosurgical intervention for unruptured intracranial aneurysms (UIAs) in the elderly population is rapidly increasing. Cerebral aneurysm coiling (CACo) is favored over cerebral aneurysm clipping (CAC) in elderly patients, yet some elderly individuals still undergo CAC. The cost-effectiveness of treating UIAs requires further exploration. Understanding the effect of intervention on hospital charges and length of stay (LOS) as well as perioperative mortality and complications can further shed light on its economic impact. The purpose of this study was to analyze the cost and perioperative outcomes of UIAs in elderly patients (≥ 65 years of age) after CACo or CAC intervention.

METHODS

Retrospective cohorts of CACo and CAC admissions were extracted from National (Nationwide) Inpatient Sample data obtained between 2002 and 2013, forming parallel intervention groups to compare the following outcomes between elderly and nonelderly patients: average LOS and mean hospital admission costs, in-hospital mortality, and complications. Covariates included sex, race or ethnicity, and comorbidities.

RESULTS

Elderly patients undergoing CAC experienced an average LOS of 8.0 days, whereas elderly patients undergoing CACo stayed an average of 3.2 days. The mean hospital charges incurred during admission totaled $95,960 in the elderly patients who underwent CAC versus $87,960 in the ones who underwent CACo. Elderly patients in whom CAC was performed had a 2.2% rate of in-hospital mortality, with a 2.6 greater adjusted odds of in-hospital mortality than nonelderly patients treated with CAC. In contrast, elderly patients who underwent CACo had a 1.36 greater adjusted odds of in-hospital mortality than their nonelderly counterparts. Compared to nonelderly patients receiving both interventions, elderly individuals had a significantly higher prevalence of various comorbidities and incidence of complications. Elderly patients who received CAC experienced a 10.3% incidence rate of perioperative stroke, whereas their CACo counterparts experienced this complication at a rate of 3.5%. Elderly patients treated with CAC had greater odds of perioperative acute renal failure, whereas their CACo counterparts had greater odds of perioperative deep venous thrombosis and pulmonary embolism.

CONCLUSIONS

Intervention with CAC and CACo in the elderly is resource intensive and is associated with higher risk than in the nonelderly. Those deciding between intervention and conservative management should consider these risks and costs, especially the 2.2% postoperative mortality rate associated with CAC in the elderly population. Further comparative cost-effectiveness research is needed to weigh these costs and outcomes against those of conservative management.

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Kevin T. Huang, Michael A. Silva, Alfred P. See, Kyle C. Wu, Troy Gallerani, Hasan A. Zaidi, Yi Lu, John H. Chi, Michael W. Groff, and Omar M. Arnaout

OBJECTIVE

Recent advances in computer vision have revolutionized many aspects of society but have yet to find significant penetrance in neurosurgery. One proposed use for this technology is to aid in the identification of implanted spinal hardware. In revision operations, knowing the manufacturer and model of previously implanted fusion systems upfront can facilitate a faster and safer procedure, but this information is frequently unavailable or incomplete. The authors present one approach for the automated, high-accuracy classification of anterior cervical hardware fusion systems using computer vision.

METHODS

Patient records were searched for those who underwent anterior-posterior (AP) cervical radiography following anterior cervical discectomy and fusion (ACDF) at the authors’ institution over a 10-year period (2008–2018). These images were then cropped and windowed to include just the cervical plating system. Images were then labeled with the appropriate manufacturer and system according to the operative record. A computer vision classifier was then constructed using the bag-of-visual-words technique and KAZE feature detection. Accuracy and validity were tested using an 80%/20% training/testing pseudorandom split over 100 iterations.

RESULTS

A total of 321 total images were isolated containing 9 different ACDF systems from 5 different companies. The correct system was identified as the top choice in 91.5% ± 3.8% of the cases and one of the top 2 or 3 choices in 97.1% ± 2.0% and 98.4 ± 13% of the cases, respectively. Performance persisted despite the inclusion of variable sizes of hardware (i.e., 1-level, 2-level, and 3-level plates). Stratification by the size of hardware did not improve performance.

CONCLUSIONS

A computer vision algorithm was trained to classify at least 9 different types of anterior cervical fusion systems using relatively sparse data sets and was demonstrated to perform with high accuracy. This represents one of many potential clinical applications of machine learning and computer vision in neurosurgical practice.

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Robert Howman-Giles, Michael Besser, Ian H. Johnston, and Merle Da Silva

✓ A pineal germinoma in a 9-month-old boy is described. After surgical resection and cerebrospinal fluid diversionary shunting, the child developed hematogenous metastases which showed marked increased uptake on radionuclide gallium-67 scans.

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Michael A. Silva, Alfred P. See, Hormuzdiyar H. Dasenbrock, Ramsey Ashour, Priyank Khandelwal, Nirav J. Patel, Kai U. Frerichs, and Mohammad A. Aziz-Sultan

Successful application of endovascular neurosurgery depends on high-quality imaging to define the pathology and the devices as they are being deployed. This is especially challenging in the treatment of complex cases, particularly in proximity to the skull base or in patients who have undergone prior endovascular treatment. The authors sought to optimize real-time image guidance using a simple algorithm that can be applied to any existing fluoroscopy system. Exposure management (exposure level, pulse management) and image post-processing parameters (edge enhancement) were modified from traditional fluoroscopy to improve visualization of device position and material density during deployment. Examples include the deployment of coils in small aneurysms, coils in giant aneurysms, the Pipeline embolization device (PED), the Woven EndoBridge (WEB) device, and carotid artery stents. The authors report on the development of the protocol and their experience using representative cases.

The stent deployment protocol is an image capture and post-processing algorithm that can be applied to existing fluoroscopy systems to improve real-time visualization of device deployment without hardware modifications. Improved image guidance facilitates aneurysm coil packing and proper positioning and deployment of carotid artery stents, flow diverters, and the WEB device, especially in the context of complex anatomy and an obscured field of view.

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Michael A. Silva, Alfred P. See, Priyank Khandelwal, Ashutosh Mahapatra, Kai U. Frerichs, Rose Du, Nirav J. Patel, and Mohammad A. Aziz-Sultan

OBJECTIVE

Paraclinoid aneurysms represent approximately 5% of intracranial aneurysms (Drake et al. [1968]). Visual impairment, which occurs in 16%–40% of patients, is among the most common presentations of these aneurysms (Day [1990], Lai and Morgan [2013], Sahlein et al. [2015], and Silva et al. [2017]). Flow-diverting stents, such as the Pipeline Embolization Device (PED), are increasingly used to treat these aneurysms, in part because of their theoretical reduction of mass effect (Fiorella et al. [2009]). Limited data on paraclinoid aneurysms treated with a PED exist, and few studies have compared outcomes of patients after PED placement with those of patients after clipping or coiling.

METHODS

The authors performed a retrospective analysis of 115 patients with an aneurysm of the cavernous to ophthalmic segments of the internal carotid artery treated with clipping, coiling, or PED deployment between January 2011 and March 2017. Postoperative complications were defined as new neurological deficit, aneurysm rupture, recanalization, or other any operative complication that required reintervention.

RESULTS

A total of 125 paraclinoid aneurysms in 115 patients were treated, including 70 with PED placement, 23 with coiling, and 32 with clipping. Eighteen (14%) aneurysms were ruptured. The mean aneurysm size was 8.2 mm, and the mean follow-up duration was 18.4 months. Most aneurysms were discovered incidentally, but visual impairment, which occurred in 21 (18%) patients, was the most common presenting symptom. Among these patients, 15 (71%) experienced improvement in their visual symptoms after treatment, including 14 (93%) of these 15 patients who were treated with PED deployment. Complete angiographic occlusion was achieved in 89% of the patients. Complications were seen in 17 (15%) patients, including 10 (16%) after PED placement, 2 (9%) after coiling, and 5 (17%) after clipping. Patients with incomplete aneurysm occlusion had a higher rate of procedural complications than those with complete occlusion (p = 0.02). The rate of postoperative visual improvement was significantly higher among patients treated with PED deployment than in those treated with coiling (p = 0.01). The significant predictors of procedural complications were incomplete occlusion (p = 0.03), hypertension, (p = 0.04), and diabetes (p = 0.03).

CONCLUSIONS

In a large series in which patient outcomes after treatment of paraclinoid aneurysms were compared, the authors found a high rate of aneurysm occlusion and a comparable rate of procedural complications among patients treated with PED placement compared with the rates among those who underwent clipping or coiling. For patients who presented with visual symptoms, those treated with PED placement had the highest rate of visual improvement. The results of this study suggest that the PED is an effective and safe modality for treating paraclinoid aneurysms, especially for patients who present with visual symptoms.

Free access

Henry Chang, Michael A. Silva, Alexander Giner, Selina Ancheta, José G. Romano, Ricardo Komotar, and Iahn Cajigas

OBJECTIVE

Timely ventriculostomy placement is critical in the management of neurosurgical emergencies. Prompt external ventricular drain (EVD) placement has been shown to improve long-term patient outcomes and decrease the length of ICU and hospital stays. Successful and efficient EVD placement requires seamless coordination among multiple healthcare teams. In this study, the authors sought to identify factors favoring delayed ventriculostomy via a quality improvement initiative and to implement changes to expedite EVD placement.

METHODS

Through process mapping, root cause analysis, and interviews with staff, the authors identified the lack of a standardized mechanism for alerting necessary healthcare teams as a major contributor to delays in EVD placement. In December 2019, an EVD alert system was developed to automatically initiate an EVD placement protocol and to alert the neurosurgery department, pharmacy, core laboratory, and nursing staff to prepare for EVD placement. The time to EVD placement was tracked prospectively using time stamps in the electronic medical record.

RESULTS

A total of 20 patients who underwent EVD placement between December 2019 and April 2021, during the EVD alert protocol initiation, and 18 preprotocol control patients (January 2018 to December 2019) met study inclusion criteria and were included in the analysis. The mean time to EVD placement in the control group was 71.88 minutes compared with 50.3 minutes in the EVD alert group (two-tailed t-test, p = 0.025). The median time to EVD placement was 64 minutes in the control group compared with 52 minutes in the EVD alert group (rank-sum test, p = 0.0184). All patients from each cohort exhibited behavior typical of stable processes, with no violation of Shewhart rules and no special cause variations on statistical process control charts.

CONCLUSIONS

A quality improvement framework helped identify sources of delays to EVD placement in the emergency department. An automated EVD alert system was a simple intervention that significantly reduced the time to EVD placement in the emergency department and can be easily implemented at other institutions to improve patient care.

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Michael A. Silva, Henry Chang, John Weng, Nicole E. Hernandez, Ashish H. Shah, Shelly Wang, Toba Niazi, and John Ragheb

OBJECTIVE

Quadrigeminal cistern arachnoid cysts (QACs) are congenital lesions that can cause pineal region compression and obstructive hydrocephalus when sufficiently large. Management of these cysts is controversial and rates of reintervention are high. Given the limited data on the management of QACs, the authors retrospectively reviewed 20 years of cases managed at their institution and performed a literature review on this topic.

METHODS

The authors performed a retrospective analysis of patients treated for QAC at their institution between 2001 and 2021. They also performed a literature review of studies published between 1980 and 2021 that reported at least 5 patients treated for QACs. Patient characteristics, radiographic findings, management course, and postoperative follow-up data were collected and analyzed.

RESULTS

A total of 12 patients treated for a QAC at the authors’ institution met the inclusion criteria for analysis. Median age was 9 months, mean cyst size was 5.1 cm, and 83% of patients had hydrocephalus. Initial treatment was endoscopic fenestration in 92% of these patients, 27% of whom had an endoscopic third ventriculostomy (ETV) performed concurrently. Reintervention was required in 42% of patients. Cases that required reintervention had a statistically significant lower median age at the initial intervention (5 months) than the cases that did not require reintervention (24.33 months; p = 0.018). There were no major complications. At a mean follow-up of 5.42 years, 83% of patients had improvement or resolution of their symptoms. A literature review revealed 7 studies that met the inclusion criteria, totaling 108 patients with a mean age of 8.8 years. Eighty-seven percent of patients had hydrocephalus at presentation. Ninety-two percent of patients were initially treated with endoscopic fenestration, 44% of whom underwent concurrent ETV. Complications occurred in 17.6% of cases, and reintervention was required in 30.6% of cases. The most frequent reason for reintervention was untreated or unresolved hydrocephalus after the initial procedure.

CONCLUSIONS

Endoscopic fenestration is the most common treatment for QACs. While generally safe and effective, there is a high rate of reintervention after initial treatment of QACs, which may be associated with a younger age at the first intervention. Additionally, identifying patients who require initial treatment of hydrocephalus is critically important, as the literature suggests that untreated hydrocephalus is a common cause of reintervention.

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Michael K. Morgan, Ian H. Johnston, and Merl de Silva

✓ A 17-year-old girl with unilateral blindness and exophthalmos was found to have Bonnet-Dechaume-Blanc syndrome without retinal arteriovenous communications. The arteriovenous malformation was managed by combined intracranial resection, ophthalmic artery ligation, and selective embolization of the external carotid component.