The first neurosurgical service in Texas: neurosurgery at the University of Texas Medical Branch (1937-2023)

The authors present a historical analysis of the first neurosurgical service in Texas. Initially established as a subdivision within the Department of Surgery in the early 1900s, this service eventually evolved into the Department of Neurosurgery at the University of Texas Medical Branch (UTMB). The pivotal contributions of individual chiefs of neurosurgery throughout the years are highlighted, emphasizing their roles in shaping the growth of the neurosurgery division. The challenges faced by the neurosurgical division are documented, with particular attention given to the impact of hurricanes on Galveston Island, Texas, which significantly disrupted hospital operations. Additionally, a detailed account of recent clinical and research expansions is presented, along with the future directions envisioned for the Department of Neurosurgery. This work offers a comprehensive historical narrative of the neurosurgical service at UTMB, chronicling its journey of growth and innovation, and underscoring its profound contributions to Galveston's healthcare services, extending its impact beyond the local community.

COVID-19 and Stroke Recurrence by Subtypes: A Propensity-Score Matched Analyses of Stroke Subtypes in 44,994 Patients

Background

Methods

Results

Conclusions

Trends and Outcomes of Primary, Rescue, and Adjunct Middle Meningeal Artery Embolization for Chronic Subdural Hematomas

BACKGROUND

Middle meningeal artery embolization (MMAE) is an effective minimally invasive treatment for chronic subdural hematomas (cSDHs). The authors investigated outcomes of primary, adjunct, and rescue MMAE and primary surgery for the treatment of cSDH using a large-scale national database.

METHODS

A retrospective study of all patients who underwent MMAE and/or surgery to treat cSDH was performed using the TriNetX Analytics Network. Primary MMAE was compared with adjunct and rescue MMAE and primary surgery. Primary outcomes included headache, facial weakness, mortality, and treatment failure, within 6 months.

RESULTS

A total of 4274 patients with cSDH met the inclusion criteria. Of these, 209 (4.9%) were treated with primary MMAE, 4050 (94.8%) were treated with primary surgery, 15 (0.35%) were treated using MMAE as an adjunct therapy, and 18 (0.42%) were treated using MMAE as a rescue following a failed surgical intervention. There were no significant differences in headache, facial weakness, and mortality between the groups. Patients who underwent primary MMAE had a significantly higher Charlson comorbidity index (P < 0.0001) than those who underwent primary surgery. The need for surgical rescue was not significantly different between primary MMAE, adjunct MMAE, and rescue MMAE (P > 0.05). Additionally, patients with primary surgery had significantly higher treatment failure than those with primary MMAE (odds ratio = 2.11, 95% confidence interval = 1.11-4.01, P = 0.020).

CONCLUSIONS

This analysis suggests no significant difference in the need for surgical rescue, complication, or mortality between primary MMAE, adjunct MMAE, and rescue MMAE. Additionally, primary MMAE is associated with a significantly lower need for surgical rescue than primary surgery.

Trends and Outcomes of Endovascular Embolization and Surgical Clipping for Ruptured Intracranial Aneurysms: A Propensity-Matched Study of 1332 Patients in the United States

OBJECTIVE

To describe recent trends in treatment and outcomes of endovascular coil embolization and microsurgical clipping treatment strategies for ruptured intracranial aneurysms.

METHODS

Using International Classification of Diseases, Tenth Revision, codes, 1332 propensity-matched patients >18 years old who underwent coiling or clipping were identified. Patient demographics, baseline characteristics, comorbidities, and clinical outcomes were evaluated within 1 year postoperatively. Pooled and individual studies of the International Classification of Diseases codes investigated differences in clinical outcomes owing to aneurysm location. Outcomes were mortality, intensive care, surgical complications, hydrocephalus, and vasospasm.

RESULTS

After propensity matching for baseline characteristics and comorbidities, 666 patients were included in the coiling and clipping cohorts. There was no significant difference in 1-year mortality between cohorts. However, incidence of intensive care, surgical/medical complications, and vasospasm was significantly lower in the pooled coiling cohort (P = 0.02, P = 0.03, and P = 0.014) compared with the clipping cohort within 1 year postoperatively. Additionally, individual International Classification of Diseases code analysis revealed that coiling of anterior communicating artery aneurysms was associated with significantly fewer surgical/medical complications and hydrocephalus (P = 0.0008 and P = 0.015) and coiling of posterior communicating artery aneurysms was associated with substantially less vasospasm treatment (P = 0.034) compared with the respective clipping cohorts.

CONCLUSIONS

Analysis revealed no difference in 1-year mortality between coiling and clipping. Clinical outcomes, including intensive care, surgical complications, and vasospasm, favored coiling regardless of aneurysm location. Patients with coiling of anterior communicating artery aneurysms had significantly less hydrocephalus and patients with coiling of posterior communicating artery aneurysms had substantially less vasospasm treatment within 1 year compared with the clipping cohort.

A History of Cerebrovascular Disease Is Independently Associated with Increased Morbidity and Mortality in Patients with COVID-19: A Cohort Study of 369,563 COVID-19 Cases in the USA

Objectives

We set out to evaluate the risk for severe coronavirus disease 2019 (COVID-19) infection and subsequent cerebrovascular disease (CVD) in the population with a prior diagnosis of CVD within the past 10 years.

Methods

We utilized the TriNetX Analytics Network to query 369,563 CO­VID-19 cases up to December 30, 2020. We created 8 cohorts of patients with COVID-19 diagnosis based on a previous diagnosis of CVD. We measured the odds ratios, relative risks, risk differences for hospitalizations, ICU/critical care services, intubation, mortality, and CVD recurrence within 90 days of COVID-19 diagnosis, compared to a propensity-matched cohort with no prior history of CVD within 90 days of COVID-19 diagnosis.

Results

369,563 patients had a confirmed diagnosis of COVID-19 with a subset of 22,497 (6.09%) patients with a prior diagnosis of CVD within 10 years. All cohorts with a CVD diagnosis had an increased risk of hospitalization, critical care services, and mortality within 90 days of COVID-19 diagnosis. Additionally, the data demonstrate that any history of CVD is associated with significantly increased odds of subsequent CVD post-COVID-19 compared to a matched control.

Conclusions

CVD, a known complication of CO­VID-19, is more frequent in patients with a prior history of CVD. Patients with any previous diagnosis of CVD are at higher risks of morbidity and mortality from COVID-19 infection. In patients admitted to the ED due to COVID-19 symptoms, these risk factors should be promptly identified as delayed or missed risk stratification and could lead to an ineffective and untimely diagnosis of subsequent CVD, which would lead to protracted hospitalization and poor prognosis.

Middle Meningeal Artery Embolization for Chronic Subdural Hematoma: A National Database Study of 191 Patients in the United States

BACKGROUND

Middle meningeal artery embolization (MMAE) has been used as an effective minimally invasive treatment for chronic subdural hematoma (cSDH). The demographics and clinical outcomes after MMAE treatment for cSDH have not yet been studied using a national database.

METHODS

We queried all MMAE cases up to October 7, 2020, from the TriNetX Analytics Network. We identified patients >18 years old who underwent MMAE for treatment of cSDH. Patient demographics, baseline characteristics, comorbidities, and clinical outcomes were evaluated within 180 days after MMAE. Analyses of 180-day mortality and recurrence were performed after propensity score matching to control for baseline characteristics and comorbidities.

RESULTS

The study included 191 patients (mean age 71.2 ± 13.5 years, 73.3% male, 69.6% White, 13.6% Black/African American, and 16.8% other race). Essential hypertension (71.3%), heart disease (62.8%), type 2 diabetes mellitus (27.2%), nicotine dependence (23.6%), chronic kidney disease (19.4%), and overweight/obesity (19.4%) were among the most prevalent comorbidities. At presentation, 20.4% and 40.3% of patients were on antiplatelet and anticoagulation therapy, respectively. Outcomes within 180-day follow-up were 6.3% (1.0%-5.8% when propensity matched) for mortality (12 patients), 7.3% for craniotomy/craniectomy after MMAE (14 patients), 0.52%-5.2% for burr hole procedures (1-10 patients), and no patients with low vision/blindness.

CONCLUSIONS

MMAE is a safe and effective minimally invasive procedure for treatment of cSDH. This is the first analysis of patients undergoing MMAE for cSDH using a national database.

How the elderly fare after brain tumor surgery compared to younger patients within a 30-day follow-up: A National surgical Quality Improvement Program analysis of 30,183 cases

The growing elderly population in Western societies has led to an increasing number of primary brain tumors occurring in patients beyond the age of 65. The purpose of this study was to assess and compare the safety, efficacy, and outcomes of oncological craniotomy procedures between patients above and below 65 years. We performed a retrospective analysis of the ACS-NSQIP database to identify patients undergoing supratentorial and infratentorial tumor excisions by neurosurgeons between 2008 and 2016. We stratified them based on a cutoff age of 65 years and analyzed for minor and major complications, reoperation, the total length of hospital stay, and mortality within a standardized 30-day follow-up. Among the 30,183 analyzed patients, 9,652 (32%) were elderly (age ≥ 65). The bivariate analysis demonstrated significantly increased risk of complications, including major and minor complications and mortality in patients with metabolic syndrome, preoperative steroid use, and ASA classification ≥3. (p-value ≤ 0.001***). After controlling for confounding variables in our logistic regression models, older age, metabolic syndrome, extended operative time beyond 5 h, dependent functional health status, ASA class ≥3, steroid use pre-operatively, and black/African American race were found to be significant predictors of major and minor complication. Our study provides a comprehensive analysis of perioperative risk factors and predictors of adverse outcomes following craniotomy for supratentorial and infratentorial tumors in elderly patients. We identified increased age as an independent risk factor for minor and major adverse events as well as extended hospitalization.

L5 Fracture Dislocation Secondary to Cold Abscess Treated by Posterior Corpectomy With Expandable Cage Placement

Infections of the lumbar spine can have serious sequelae, including neurological deficits, paralysis, and death. Prolonged infection can result in fracture of the vertebrae, local abscesses, and infiltration and compression of local vascular structures. In cases with significant instability or neurological compromise, a common treatment approach is vertebral corpectomy with interbody cage followed by long-term antibiotics.

The following case describes a patient with a three-month history of progressively worsening lower back pain, lower extremity radiculopathy, and bilateral lower extremity edema, in the setting of a nontraumatic three-column fracture dislocation of L5 with grade 4 retrolisthesis of L4 on L5. A posterior-only corpectomy with placement of an expandable cage, to be followed by pedicle screw placement from L3-S1/ilium, was performed. The procedure was successful, and the patient was discharged on postoperative day 5 without complication and with resolution of his edema. Histopathological analysis demonstrated acute and chronic inflammation, but extensive tests and cultures failed to identify a causative organism.

This case highlights several interesting features, including a technically challenging and seldom-performed procedure, as well as the ability of lumbar spinal infections to present with leg edema due to involvement the inferior vena cava and iliac vessels. For patients with three-column fractures of L5 due to an inflammatory process or trauma, a single-stage posterior corpectomy with placement of an expandable cage may be considered as an appropriate treatment option.

Machine learning applications for the differentiation of primary central nervous system lymphoma from glioblastoma on imaging: a systematic review and meta-analysis

OBJECTIVEGlioblastoma (GBM) and primary central nervous system lymphoma (PCNSL) are common intracranial pathologies encountered by neurosurgeons. They often may have similar radiological findings, making diagnosis difficult without surgical biopsy; however, management is quite different between these two entities. Recently, predictive analytics, including machine learning (ML), have garnered attention for their potential to aid in the diagnostic assessment of a variety of pathologies. Several ML algorithms have recently been designed to differentiate GBM from PCNSL radiologically with a high sensitivity and specificity. The objective of this systematic review and meta-analysis was to evaluate the implementation of ML algorithms in differentiating GBM and PCNSL.METHODSThe authors performed a systematic review of the literature using PubMed in accordance with PRISMA guidelines to select and evaluate studies that included themes of ML and brain tumors. These studies were further narrowed down to focus on works published between January 2008 and May 2018 addressing the use of ML in training models to distinguish between GBM and PCNSL on radiological imaging. Outcomes assessed were test characteristics such as accuracy, sensitivity, specificity, and area under the receiver operating characteristic curve (AUC).RESULTSEight studies were identified addressing use of ML in training classifiers to distinguish between GBM and PCNSL on radiological imaging. ML performed well with the lowest reported AUC being 0.878. In studies in which ML was directly compared with radiologists, ML performed better than or as well as the radiologists. However, when ML was applied to an external data set, it performed more poorly.CONCLUSIONSFew studies have applied ML to solve the problem of differentiating GBM from PCNSL using imaging alone. Of the currently published studies, ML algorithms have demonstrated promising results and certainly have the potential to aid radiologists with difficult cases, which could expedite the neurosurgical decision-making process. It is likely that ML algorithms will help to optimize neurosurgical patient outcomes as well as the cost-effectiveness of neurosurgical care if the problem of overfitting can be overcome.

Effect of an additional neurosurgical resident on procedure length, operating room time, estimated blood loss, and post-operative length-of-stay

Introduction: Neurosurgical residency training is costly, with expenses largely borne by the academic institutions that train residents. One expense is increased operative duration, which leads to poorer patient outcomes. Although other studies have assessed the effect of one resident assisting, none have investigated two residents; thus, we sought to investigate if two residents versus one scrubbed-in impacted operative time, estimated blood loss (EBL), and length-of-stay (LOS).Methods: In this retrospective review of patients who underwent a neurosurgical procedure involving one or two residents between January 2013 and April 2016, we performed multivariable linear regression to determine if there was an association between resident participation and case length, operating room time, EBL, and LOS. We also included patient demographics, attending surgeon, day of the week, start time, pre-operative LOS, procedure performed, and other variables in our model. Only procedures performed at least 40 times during the study period were analyzed.Results: Of 860 procedures that met study criteria, 492 operations were one of six procedures performed at least 40 times, which were anterior cervical discectomy and fusion, cerebrospinal fluid (CSF) shunt insertion, CSF shunt revision, lumbar laminectomy, intracranial hematoma evacuation, and non-skull base, supratentorial parenchymal brain tumor resection. An additional resident was associated with a 35.1-min decrease (p = .01) in operative duration for lumbar laminectomies. However, for intracranial hematoma evacuations, an extra resident was associated with a 24.1 min increase (p = .03) in procedural length. There were no significant differences observed in the other four surgeries.Conclusion: An additional resident may lengthen duration of intracranial hematoma evacuations. However, two residents scrubbed-in were associated with decreased lumbar laminectomy duration. Overall, an extra resident does not increase procedural duration, total operating room utilization, EBL, or post-operative LOS. Allowing two residents to scrub in may be a safe and cost-effective method of educating neurosurgical residents.

Low-Dose Gamma Knife Radiosurgery for Vestibular Schwannomas: Tumor Control and Cranial Nerve Function Preservation After 11 Gy

OBJECTIVES

This study aims to report tumor control rates and cranial nerve function after low dose (11.0 Gy) Gamma knife radiosurgery (GKRS) in patients with vestibular schwannomas.

METHODS

A retrospective chart review was performed on 30 consecutive patients with vestibular schwannomas treated from March 2004 to August 2010 with GKRS at the Robert H. Lurie Comprehensive Cancer Center of Northwestern University. The marginal dose for all patients was 11.0 Gy prescribed to the 50% isodose line. Median follow-up time was 42 months. The median treatment volume was 0.53 cm3. Hearing data were obtained from audiometry reports before and after radiosurgery.

RESULTS

The actuarial progression free survival (PFS) based on freedom from surgery was 100% at 5 years. PFS based on freedom from persistent growth was 91% at 5 years. One patient experienced tumor progression requiring resection at 87 months. Serviceable hearing, defined as Gardner-Robertson score of I-II, was preserved in 50% of patients. On univariate and multivariate analyses, only higher mean and maximum dose to the cochlea significantly decreased the proportion of patients with serviceable hearing.

CONCLUSION

Vestibular schwannomas can be treated with low doses (11.0 Gy) of GKRS with good tumor control and cranial nerve preservation.

Comparing Radiation Dose from Conventional Fluoroscopy to Intraoperative Cone Beam CT (O-arm) during Percutaneous Lesioning Procedures of the Gasserian Ganglion

Introduction: The use of intraoperative CT-guidance during the percutaneous treatment of trigeminal neuralgia has become increasingly popular due to the greater ease of foramen ovale cannulation and decreased procedure times. Concerns regarding radiation dose to the patient, however, remain unaddressed. We sought to compare the emitted radiation dose from fluoroscopy with intraoperative CT for these procedures.

Methods: A retrospective review of percutaneous lesioning procedures for trigeminal neuralgia performed between 2010 until 2012 at our institution was conducted and radiation doses to the patient were recorded. We subsequently simulated four separate percutaneous trigeminal rhizotomies using the O-arm intraoperative CT (Medtronics, Minneapolis, MN, USA) to cannulate the foramen ovale bilaterally in two formalin-fixed cadaver heads.

Results: Seventeen successful percutaneous treatments for trigeminal neuralgia were performed during the study period. Eleven procedures containing complete records were included in the final analysis. For procedures using fluoroscopy, the mean dosage was 15.2 mGys (range: 1.15 - 47.95, 95% CI 7.34 – 22.99). Radiation dosage from the O-arm imaging system was 16.55 mGy for all four cases. An unequal variance t-test did not reach statistical significance (p=0.42).

Conclusions: We did not observe a significant difference in radiation dose delivered to subjects when comparing CT-guided foramen ovale cannulation relative to fluoroscopy for percutaneous lesioning of the Gasserian ganglion. Additional study is required under operational settings.

Spontaneous Thrombosis and Subsequent Recanalization of a Developmental Venous Anomaly

Developmental venous anomalies (DVA) are among the most common congenital malformations of the cerebral angioarchitecture. Spontaneous thrombosis of this entity is rare, and our review of the literature found only 31 reported cases of symptomatic spontaneous thrombosis of developmental venous anomalies. Here, we report a unique case describing the spontaneous thrombosis of a DVA leading to venous infarction and subsequent recanalization. The patient was a previously healthy 21-year-old male who presented with an acute onset of partial seizures. Following negative hypercoagulability studies and along with CT (computed tomography) and MR (magnetic resonance) imaging, the patient was treated with anticoagulant therapy and demonstrated complete functional recovery. Knowledge from our literature review of similar cases combined with the experience gained from this patient’s treatment leads us to suggest that spontaneous DVA thrombosis and venous infarction generally has a good outcome despite initially devastating neurologic deficits. Additionally, the rarity of spontaneous DVA thromboses lends itself to the need to identify possible predisposing risk factors, chief amongst these being hypercoagulopathies.

Comparison of open and minimally invasive surgery for intradural-extramedullary spine tumors

OBJECT

Patients with symptomatic intradural-extramedullary (ID-EM) tumors may be successfully treated with resection of the lesion and decompression of associated neural structures. Studies of patients undergoing open resection of these tumors have reported high rates of gross-total resection (GTR) with minimal long-term neurological deficit. Case reports and small case series have suggested that these patients may be successfully treated with minimally invasive surgery (MIS). These studies have been limited by small patient populations. Moreover, there are no studies directly comparing perioperative outcomes between patients treated with open resection and MIS. The objective of this study was to compare perioperative outcomes in patients with ID-EM tumors treated using open resection or MIS.

METHODS

A retrospective review was performed using data collected from 45 consecutive patients treated by open resection or MIS for ID-EM spine tumors. These patients were treated over a 9-year period between April 2003 and October 2012 at Northwestern University and the University of Chicago. Statistical analysis was performed to compare perioperative outcomes between the two groups.

RESULTS

Of the 45 patients in the study, 27 were treated with the MIS approach and 18 were treated with the open approach. Operative time was similar between the two groups: 256.3 minutes in the MIS group versus 241.1 minutes in the open group (p = 0.55). Estimated blood loss was significantly lower in the MIS group (133.7 ml) compared with the open group (558.8 ml) (p < 0.01). A GTR was achieved in 94.4% of the open cases and 92.6% of the MIS cases (p = 0.81).

The mean hospital stay was significantly shorter in the MIS group (3.9 days) compared with the open group (6.1 days) (p < 0.01). There was no significant difference between the complication rates (p = 0.32) and reoperation rates (p = 0.33) between the two groups. Multivariate analysis demonstrated an increased rate of complications in cervical spine tumors (OR 15, p = 0.05).

CONCLUSIONS

Thoracolumbar ID-EM tumors may be safely and effectively treated with either the open approach or an MIS approach, with an equivalent rate of GTR, perioperative complication rate, and operative time. Patients treated with an MIS approach may benefit from a decrease in operative blood loss and shorter hospital stays.

Venous thromboembolism in high grade glioma among surgical patients: results from a single center over a 10 year period

Patients with high-grade glioma are at elevated risk of venous thromboembolism (VTE). The relationship between VTE and survival in glioma patients remains unclear, as does the optimal protocol for chemoprophylaxis. The purpose of this study was to assessthe incidence of and risk factors associated with VTE in patients with high-grade glioma, and the correlation between VTE and survival in this population. Furthermore, we sought to define a protocol for perioperative DVT prophylaxis. This was a retrospective review of patients who underwent craniotomy for resection of high-grade glioma (WHO grade III or IV) at Northwestern University between 1999 and 2010. A total of 336 patients met inclusion criteria. 53 patients developed postoperative VTE (15.7 %). Median survival was 12.0 months and was not significantly different between VTE(+) and VTE(-) patients. Demographics and surgical factors were not significantly correlated with VTE development. Prior history of VTE was highly predictive of postoperative VTE (OR 7.1, p < .01), as was seizure (OR 2.4, p = .005). Increased duration of postoperative ICU stay was also a risk factor for VTE (p = .025). 25 patients in our study received prophylactic anticoagulation(pAC) with either heparin or enoxaparin. Early initiation of pAC was associated with decreased incidence of VTE (p = .042). There were no hemorrhagic complications in patients receiving pAC. VTE is a common complication in high-grade glioma patients. Early initiation of anticoagulation is safe and may decrease the risk of VTE. We recommend initiation of chemoprophylaxis on postoperative day 1 in patients without contraindication.

Survival after surgery and stereotactic radiosurgery for patients with multiple intracranial metastases: results of a single-center retrospective study

OBJECTIVES

Patients with systemic cancer and a single brain metastasis who undergo treatment with resection plus radiotherapy live longer and have a better quality of life than those treated with radiotherapy alone. Historically, whole-brain radiotherapy (WBRT) has been the mainstay of radiation therapy; however, it is associated with significant delayed neurocognitive sequelae. In this study, the authors looked at survival in patients with single and multiple intracranial metastases who had undergone surgery and adjuvant stereotactic radiosurgery (SRS) to the tumor bed and synchronous lesions.

METHODS

The authors retrospectively reviewed the records from an 8-year period at a single institution for consecutive patients with brain metastases treated via complete resection of dominant lesions and adjuvant radiosurgery. The cohort was analyzed for time to local progression, synchronous lesion progression, new intracranial lesion development, systemic progression, and overall survival. The Kaplan-Meier method (stratified by age, sex, tumor histology, and number of intracranial lesions prior to surgery) was used to calculate both progression-free and overall survival. A Cox proportional-hazards regression model was also fitted with the number of intracranial lesions as the predictor and survival as the outcome controlling for disease severity, age, sex, and primary histology.

RESULTS

The median overall follow-up among the 150-person cohort eligible for analysis was 17 months. Patients had an average age of 46.2 years (range 16-82 years), and 62.7% were female. The mean (± standard deviation) number of intracranial lesions per patient was 2.5 ± 2.3. The mean time between surgery and stereotactic radiosurgery (SRS) was 3.2 ± 4.1 weeks. Primary cancers included lung cancer (43.3%), breast cancer (21.3%), melanoma (10.0%), renal cell carcinoma (6.7%), and colon cancer (6.7%). The average number of isocenters per treated lesion was 7.6 ± 6.6, and the average treatment dose was 17.8 ± 2.8 Gy. One-year survival for patients in this cohort was 52%, and the 1-year local control rate was 77%. The median (±standard error) overall survival was 13.2 ± 1.9 months. There was no difference in survival between patients with a single lesion and those with multiple lesions (p = 0.319) after controlling for age, sex, and histology of primary tumor. Patients with primary breast histology had the greatest overall median survival (22.9 ± 6.2 months); patients with colorectal cancer had the shortest overall median survival (5.3 ± 1.8 months). The most common cause of death in this series was systemic progression (79%).

CONCLUSIONS

These results confirm that 1-year survival for patients with multiple intracranial metastases treated with resection followed by SRS to both the tumor bed and synchronous lesions is similar to established outcomes for patients with a single intracranial metastasis.

Acute branch occlusion after Pipeline embolization of intracranial aneurysms

Flow-diverters are used in the treatment of large and complex intracranial aneurysms. One major concern with this concept is the potential for compromise of side branches and perforators covered by the device. We describe three patients treated with the Pipeline embolization device (PED; ev3 Endovascular, Plymouth, MN, USA) who developed immediate compromise of flow into an eloquent side branch covered by the device. Three patients, two with giant posterior circulation aneurysms and one with recurrence of a previously clipped and subsequently coiled middle cerebral artery aneurysm, were each treated by placement of a single PED. Shortly after placement of the devices, despite adequate antiplatelet and anticoagulation regimens, partial or complete occlusion of a major side branch occurred. In all three patients, the occlusion was promptly reversed with intra-arterial administration of abciximab with no clinical sequelae. These cases are concerning because branch occlusion occurred even in the setting of patients appropriately premedicated with dual antiplatelet therapy and in whom genetic testing suggested clopidogrel responsiveness. Close monitoring of patients treated with these devices is critical to establish the frequency of this and other unanticipated complications.

Intraoperative neurophysiological monitoring in spine surgery: indications, efficacy, and role of the preoperative checklist

Spine surgery carries an inherent risk of damage to critical neural structures. Intraoperative neurophysiological monitoring (IONM) is frequently used to improve the safety of spine surgery by providing real-time assessment of neural structures at risk. Evidence-based guidelines for safe and efficacious use of IONM are lacking and its use is largely driven by surgeon preference and medicolegal issues. Due to this lack of standardization, the preoperative sign-in serves as a critical opportunity for 3-way discussion between the neurosurgeon, anesthesiologist, and neuromonitoring team regarding the necessity for and goals of IONM in the ensuing case. This analysis contains a review of commonly used IONM modalities including somatosensory evoked potentials, motor evoked potentials, spontaneous or free-running electromyography, triggered electromyography, and combined multimodal IONM. For each modality the methodology, interpretation, and reported sensitivity and specificity for neurological injury are addressed. This is followed by a discussion of important IONM-related issues to include in the preoperative checklist, including anesthetic protocol, warning criteria for possible neurological injury, and consideration of what steps to take in response to a positive alarm. The authors conclude with a cost-effectiveness analysis of IONM, and offer recommendations for IONM use during various forms of spine surgery, including both complex spine and minimally invasive procedures, as well as lower-risk spinal operations.