Severe hypokalemia in a patient with subarachnoid hemorrhage.

Hypokalemia is a common electrolyte disorder in the intensive care unit. Its cause often is complex, involving both potassium losses from the body and shifts of potassium into cells. We present a case of severe hypokalemia of sudden onset in a patient being treated for subarachnoid hemorrhage in the surgical intensive care unit in order to illustrate the diagnosis and management of severe hypokalemia of unclear cause. Our patient received agents that promote renal potassium losses and treatments associated with a shift of potassium into cells. We outline the steps in diagnosis and management, focusing on the factors regulating the transcellular distribution of potassium in the body.

Contralateral interhemispheric transfalcine approach to precuneal glioblastoma: fluorescein guided microsurgical resection and endoscopic microinspection tool.

Maximum safe resection remains a primary goal in the treatment of glioblastoma, with gross-total resection conveying additional survival benefit. Multiple intraoperative visualization techniques have been developed to improve the extent of resection. Herein, the authors describe the use of fluorescein and endoscopic assistance with a novel microinspection device in achieving a gross-total resection of a deep seated precuneal glioblastoma. An interhemispheric transfalcine approach was utilized and microsurgical resection was completed with fluorescein guidance. A 45° endoscope was then used to inspect the resection bed, and remaining areas of concern were then resected under endoscopic visualization. The video can be found here: https://stream.cadmore.media/r10.3171/2021.10.FOCVID21195.

Anal cancer with cerebral metastasis: a case report.

Carcinoma of the anal canal is a relatively rare cancer with a low propensity for metastasis. A literature review identifies two cases of brain metastases from anal cancer. The authors present the case of a 63-year-old female with poorly differentiated squamous cell carcinoma of the anal canal who presented with a solitary dural-based enhancing lesion of the right parietal area. The patient underwent craniectomy and tumor resection. Histopathology confirmed the cerebral lesion to be a poorly differentiated squamous cell carcinoma, consistent with the known primary tumor of the anal canal. Although exceptionally rare, the presence of a cerebral lesion in a patient with carcinoma of the anal canal should raise the possibility of metastatic disease. Treatment decisions in patients with newly diagnosed dural-based enhancing lesions and known anal cancer should bear in mind the possibility of metastatic disease.

Differential Patterns of Referral to Neurosurgery: A Comparison of Allopathic Physicians, Osteopathic Physicians, Nurse Practitioners, Physician Assistants, and Chiropractors.

BACKGROUND: Rising cost and limited resources remain major challenges to U.S. health care and neurosurgery in particular. To ensure an efficient and cost-effective health care system, it is important that referrals to neurosurgery clinics are appropriate, and that referred patients have a reasonably high probability of requiring surgical intervention or, at a minimum, ongoing neurosurgical follow-up. This retrospective study tests the null hypothesis that the probability of a referred patient requiring surgery is independent of referring provider credentials and referring service specialty. METHODS: A database of all patients referred to the neurosurgery clinic from 2015 through 2018 (n = 5677) was reviewed; the database included referring provider, referring provider specialty, number of subsequent clinic visits, and outcome of surgery or no surgery. Associations between categorical variables were tested using a χ2 analysis with post hoc relative risk (RR) calculations and binary logistical regression. RESULTS: Compared with patients referred by allopathic physicians, patients referred by osteopathic physicians (RR, 0.63; 95% confidence interval [CI], 0.48-0.84) and those referred by nurse practitioners (RR, 0.66; 95% CI, 0.51-0.86) were significantly less likely to require surgery. Probability of surgical intervention also varied by referrer specialty. Patients referred by neurologists required surgery 35% of the time, whereas patients referred by family practitioners required surgery 19% of the time, and patients referred by pediatricians required surgery only 7% of the time (P < 0.01). Binary logistic regression revealed that referrals from nurse practitioners and osteopathic physicians were independently associated with a decreased probability of surgical intervention. CONCLUSIONS: Our data strengthen the concept of having interdisciplinary teams led by physicians at the primary care level to ensure appropriate referrals. Training and adherence to guidelines must continually be reinforced to ensure proper referrals.

Oxyhemoglobin-induced expression of R-type Ca2+ channels in cerebral arteries.

BACKGROUND AND PURPOSE: Cerebral vasospasm after subarachnoid hemorrhage (SAH) is a major contributor to mortality and morbidity after aneurysm rupture. Recently, R-type voltage-dependent Ca(2+) channel (VDCC) expression has been associated with increased cerebral artery constriction in a rabbit model of SAH. The goal of the present study was to examine whether the blood component oxyhemoglobin (oxyHb) can mimic the ability of SAH to cause R-type VDCC expression in the cerebral vasculature. METHODS: Rabbit cerebral arteries were organ cultured in serum-free media for up to 5 days in the presence or absence of purified oxyHb (10 micromol/L). Diameter changes in response to diltiazem, (L-type VDCC antagonist) and SNX-482 (R-type VDCC antagonist) were recorded at day 1, 3, or 5 in arteries constricted by elevated extracellular potassium. RT-PCR was performed on RNA extracted from arteries cultured for 5 days (+/-oxyHb) to assess VDCC expression. RESULTS: After 5 days, oxyHb-treated arteries were less sensitive and partially resistant to diltiazem compared to similar arteries organ cultured in the absence of oxyHb. Further, SNX-482 dilated arteries organ cultured for 5 days in the presence, but not in the absence, of oxyHb. RT-PCR revealed that oxyHb treated arteries expressed R-type VDCCs (Ca(V) 2.3) in addition to L-type VDCCs (Ca(V) 1.2), whereas untreated arteries expressed only Ca(V) 1.2. CONCLUSIONS: These results demonstrate that oxyhemoglobin exposure for 5 days induces the expression of Ca(V) 2.3 in cerebral arteries. We propose that oxyhemoglobin contributes to enhanced cerebral artery constriction after SAH via the emergence of R-type VDCCs.

Oxyhemoglobin-induced suppression of voltage-dependent K+ channels in cerebral arteries by enhanced tyrosine kinase activity.

Cerebral vasospasm following aneurysmal subarachnoid hemorrhage (SAH) has devastating consequences. Oxyhemoglobin (oxyhb) has been implicated in SAH-induced cerebral vasospasm as it causes cerebral artery constriction and increases tyrosine kinase activity. Voltage-dependent, Ca(2+)-selective and K(+)-selective ion channels play an important role in the regulation of cerebral artery diameter and represent potential targets of oxyhb. Here we provide novel evidence that oxyhb selectively decreases 4-aminopyridine sensitive, voltage-dependent K(+) channel (K(v)) currents by approximately 30% in myocytes isolated from rabbit cerebral arteries but did not directly alter the activity of voltage-dependent Ca(2+) channels or large conductance Ca(2+)-activated (BK) channels. A combination of tyrosine kinase inhibitors (tyrphostin AG1478, tyrphostin A23, tyrphostin A25, genistein) abolished both oxyhb-induced suppression of K(v) channel currents and oxyhb-induced constriction of isolated cerebral arteries. The K(v) channel blocker 4-aminopyridine also inhibited oxyhb-induced cerebral artery constriction. The observed oxyhb-induced decrease in K(v) channel activity could represent either channel block, or a decrease in K(v) channel density on the plasma membrane. To explore whether oxyhb altered trafficking of K(v) channels to the plasma membrane, we used an antibody generated against an extracellular epitope of K(v)1.5 channels. In the presence of oxyhb, staining of K(v)1.5 on the plasma membrane surface was markedly reduced. Furthermore, oxyhb caused a loss of spatial distinction between staining with K(v)1.5 and the general anti-phosphotyrosine antibody PY-102. We propose that oxyhb-induced suppression of K(v) currents occurs via a mechanism involving enhanced tyrosine kinase activity and channel endocytosis. This novel mechanism may contribute to oxyhb-induced cerebral artery constriction following SAH.

Subclavian artery stenosis causing transient bilateral brachial diplegia: an unusual cause of anterior spinal artery syndrome.

The author report a case of a 74-year-old man who had presented with transient bilateral brachial diplegia. Investigations led to the diagnosis and treatment of subclavian artery stenosis. There are no known published cases of subclavian artery stenosis associated with transient bilateral arm weakness, and the authors believe that a steal phenomenon leading to vertebrobasilar artery insufficiency and subsequent anterior spinal artery insufficiency may have caused these symptoms, which resolved after correction of the patient's stenosis.

Emergence of a R-type Ca2+ channel (CaV 2.3) contributes to cerebral artery constriction after subarachnoid hemorrhage.

Cerebral aneurysm rupture and subarachnoid hemorrhage (SAH) inflict disability and death on thousands of individuals each year. In addition to vasospasm in large diameter arteries, enhanced constriction of resistance arteries within the cerebral vasculature may contribute to decreased cerebral blood flow and the development of delayed neurological deficits after SAH. In this study, we provide novel evidence that SAH leads to enhanced Ca2+ entry in myocytes of small diameter cerebral arteries through the emergence of R-type voltage-dependent Ca2+ channels (VDCCs) encoded by the gene CaV 2.3. Using in vitro diameter measurements and patch clamp electrophysiology, we have found that L-type VDCC antagonists abolish cerebral artery constriction and block VDCC currents in cerebral artery myocytes from healthy animals. However, 5 days after the intracisternal injection of blood into rabbits to mimic SAH, cerebral artery constriction and VDCC currents were enhanced and partially resistant to L-type VDCC blockers. Further, SNX-482, a blocker of R-type Ca2+ channels, reduced constriction and membrane currents in cerebral arteries from SAH animals, but was without effect on cerebral arteries of healthy animals. Consistent with our biophysical and functional data, cerebral arteries from healthy animals were found to express only L-type VDCCs (CaV 1.2), whereas after SAH, cerebral arteries were found to express both CaV 1.2 and CaV 2.3. We propose that R-type VDCCs may contribute to enhanced cerebral artery constriction after SAH and may represent a novel therapeutic target in the treatment of neurological deficits after SAH.

A modeling study of idiopathic intracranial hypertension: etiology and diagnosis.

OBJECTIVE: To investigate the relationship between idiopathic intracranial hypertension (IIH) and transverse sinus stenosis through experiments performed on a validated mathematical model. METHODS: A mathematical model of intracranial pressure (ICP) dynamics has been extended to accommodate venous sinus compression through the introduction of a Starling-like resistor between the sagittal and transverse sinuses. RESULTS: In the absence of this type of resistor, the sinuses are rigid, and the model has only a unique, stable steady state with normal pressures. With resistance a function of the external pressure on the sinus, a second stable steady state may exist. This state is characterized by elevated ICP concurrent with a compressed transverse sinus. Simulations predict that a temporary perturbation that causes a transient elevation of ICP can induce a permanent transition from the normal to the higher steady state. Comparisons to clinical data from IIH patients provide supporting evidence for the validity of the model's predictions. Simulations suggest a possible clinical diagnostic technique to determine if an individual has a compressible transverse sinus and is at risk for developing IIH. CONCLUSIONS: Results of the model experiments suggest that the primary cause of IIH may be a compressible, as opposed to rigid, transverse sinus, and that the observed stenosis is a necessary characteristic of the elevated pressure state.

Ca2+ sparks and their function in human cerebral arteries.

BACKGROUND AND PURPOSE: Local Ca2+ release events (Ca2+ sparks) caused by the opening of ryanodine-sensitive Ca2+ channels in the sarcoplasmic reticulum have been suggested to oppose constriction in cerebral arteries through the activation of large-conductance Ca2+-activated K+ (BK) channels. We report the first identification and characterization of Ca2+ sparks and associated BK channel currents in smooth muscle cells isolated from human cerebral arteries. METHODS: Membrane currents and intracellular Ca2+ were measured with the use of the patch-clamp technique and laser scanning confocal microscopy. RESULTS: Ca2+ sparks with a peak fractional fluorescence change (F/F0) of 2.02 +/- 0.04 and size of 8.2 +/- 0.5 microm2 (n=108) occurred at a frequency of approximately 1 Hz in freshly isolated, cerebral artery myocytes from humans. At a holding potential of -40 mV, the majority of, but not all, Ca2+ sparks (61 of 85 sparks) were associated with transient BK currents. Consistent with a role for Ca2+ sparks in the control of cerebral artery diameter, agents that block Ca2+ sparks (ryanodine) or BK channels (iberiotoxin) were found to contract human cerebral arteries. CONCLUSIONS: This study provides evidence for local Ca2+ signaling in human arterial myocytes and suggests that these events may play an important role in control of cerebral artery diameter in humans.

Inhibition of Ca++ sparks by oxyhemoglobin in rabbit cerebral arteries.

OBJECT: Oxyhemoglobin (HbO2) causes cerebral artery constriction and is one component of blood that likely contributes to the pathogenesis of cerebral vasospasm after aneurysm rupture. This study was designed to examine the acute effect of HbO2 on subcellular Ca(++) release events (Ca(++) sparks) in cerebral artery myocytes. Calcium sparks provide a tonic hyperpolarizing and relaxing influence to vascular smooth muscle by the activation of plasmalemmal large-conductance Ca(++)-activated K+ channels. Evidence is provided that HbO2 may contract cerebral vascular muscle in part by free radical-mediated inhibition of Ca(++) sparks. METHODS: Calcium sparks were visualized in intact pressurized rabbit cerebral arteries by using laser scanning confocal microscopy and a Ca(++) indicator dye. Calcium spark frequency was reduced by approximately 65% after a 15-minute application of HbO2 (10(-4) M). The HbO2-induced decrease in Ca(++) spark frequency was prevented by a combination of the free radical scavengers superoxide dismutase and catalase. Isometric force measurements were used to characterize the role of the vascular endothelium and smooth-muscle Ca(++) channels in HbO2-induced cerebral artery contraction. The HbO2-induced contractions were independent of the vascular endothelium, but were abolished by diltiazem, a blocker of L-type voltage-dependent Ca(++) channels (VDCCs). Ryanodine, a blocker of ryanodine-sensitive Ca(++) release channels located on the sarcoplasmic reticulum, also reduced HbO2-induced contractions by approximately 50%. CONCLUSIONS: These results support the hypothesis that HbO2 may contract cerebral artery segments in part by inhibition of Ca(++) sparks, leading to decreased large-conductance Ca(++)-activated K+ channel activity, membrane potential depolarization, and enhanced Ca(++) entry through VDCCs.

Diagnosis and management of pediatric closed head injury.

Closed head injury in the pediatric population accounts for almost half of all new cases of traumatic brain injury. The incidence of severe brain injury appears to be less in children as compared to the adult population. Over the past several years, advances in recognition and treatment of traumatic brain injury have led to improved outcomes in both children and adults. It is imperative, therefore, for the pediatric surgeon dealing with head trauma to have an understanding of the common brain injuries in the pediatric population, their early recognition and initial management. In this article, early diagnosis and initial management of the most common forms of pediatric closed head injury are reviewed.

Pseudarthrosis failures of anterior subaxial cervical spine fusion using a plate with a single screw per vertebral body: a case series.

INTRODUCTION: The UNIPLATE was developed to improve operative times and limit dissection at the lateral margins of the vertebral bodies. The distinguishing character of this plate is its thin design, which requires only one screw per vertebral level (monovertebral screw plate). Most cervical spine plates, in contrast, are designed for two screws per vertebral level (bivertebral screw plate). Limited reports of the biomechanical efficacy of the UNIPLATE are available, and to the authors' knowledge, this report represents the largest clinical study of its use. METHODS: This is a retrospective chart-review study of consecutively treated patients without previous cervical spine surgery undergoing anterior cervical diskectomy and fusion at one or two levels. The primary end point was symptomatic pseudarthrosis requiring revision surgery. Pseudarthrosis is defined as a failure of bony fusion on the operated level seen on thin-cut computed tomography scans performed on symptomatic patients. The rate of revision surgery caused by symptomatic pseudarthrosis was compared between patients undergoing one- and two-level fusion surgeries treated with UNIPLATE compared with other plates with two screws per vertebral level. The minimum follow-up was 18 months. RESULTS: A total of 162 patients were identified, including 125 patients with one-level fusion and 37 patients with two-level fusion surgery. The median follow-up period was 3.3 years. A significantly greater incidence (odds ratio 10.2, P = 0.042) of reoperation for symptomatic pseudarthrosis was noted for patients treated with the UNIPLATE (4 of 13, 31%) compared with patients treated with bivertebral screw plates (1 of 24, 2.5%). No significant difference in reoperation attributable to symptomatic pseudarthrosis was noted for different plating systems for one-level fusion surgeries. CONCLUSIONS: There is an increased rate of reoperation for symptomatic pseudarthrosis after anterior cervical diskectomy and fusion surgery with the use of a monovertebral screw semiconstrained plate, particularly in two-level fusion surgeries. Use of the UNIPLATE system has since been abandoned at our institution in favor of bivertebral screw plating systems.

Chronic subdural hematoma: a sentinel health event.

OBJECTIVE: To propose that chronic subdural hematoma (CSDH) should be conceived as a sentinel event in elderly patients and offer an analysis of long-term survival after diagnosis. METHODS: A retrospective review of 301 consecutive patients ≥55 years old admitted to an academic medical center with a primary diagnosis of CSDH between January 1996 and January 2010 was performed. The effects of advanced age and surgical intervention on survival were independently assessed. These groups were compared with standardized mortality ratios (SMRs) on the basis of patient age at time of presentation. RESULTS: Mortality after diagnosis of CSDH increases with increased age at presentation. For all patients, the median survival was roughly 4 years after diagnosis (4.0 years ± 0.5). Median survival is decreased with older age at presentation, to a nadir of 1.5 years ± 0.6 for patients ≥85 years old (P = 0.0003, log-rank test). Compared with the reference data from the U.S. Centers of Disease Control and Prevention, 1-year SMR was increased in all age groups. An asymmetric increase in SMR was seen between age groups, with the greatest effect on the youngest subpopulation (SMR 2.9). CONCLUSIONS: The increased mortality rates in patients with CSDHs relative to standardized mortality data corroborate the conception of subdural hematoma as a sentinel health event.

Trends in neurosurgical complication rates at teaching vs nonteaching hospitals following duty-hour restrictions.

BACKGROUND: In 2003 the Accreditation Council for Graduate Medical Education implemented duty-hour restrictions for residents, with an unclear impact on patient care. OBJECTIVE: The authors hypothesize that implementation of duty-hour restrictions is not associated with decreased morbidity for neurosurgical patients. This hypothesis was tested with the Nationwide Inpatient Sample to examine inpatient complications associated with a common elective procedure, craniotomy for meningioma. METHODS: The Nationwide Inpatient Sample was queried for all patients admitted for elective craniotomy for meningioma from 1998 to 2008, excluding the year 2003. Each case was queried for common in-hospital postoperative complications. The complication rate was compared for 5-year epochs at teaching and nonteaching hospitals before (1998-2002) and after (2004-2008) the adoption of the Accreditation Council for Graduate Medical Education work-hour restriction. Multivariate analysis was performed to control for the effects of age and medical comorbidities. RESULTS: We identified 21177 patients who met inclusion criteria. We identified an effect of age, preexisting medical comorbidity, and timing of surgery on postoperative complication rates. At teaching hospitals, the complication rate increased from 14% to 16% (P < .001). In contrast, this increase was not mirrored at nonteaching hospitals, which saw a nearly constant postoperative complication rate of 15% from 1998 to 2002 and 15% for the years 2004 to 2008 (P = .979). This effect remained significant in a multivariate analysis including age and existing comorbidities as covariates (P = .016). CONCLUSION: In patients undergoing craniotomy for meningioma, postoperative complication rates increased at teaching hospitals, but not at nonteaching hospitals over the 5-year epochs before and after 2003.

Increased rate of complications on a neurological surgery service after implementation of the Accreditation Council for Graduate Medical Education work-hour restriction.

OBJECT: The Accreditation Council for Graduate Medical Education instituted mandatory 80-hour work-week limitations in July 2003. The work-hour restriction was met with skepticism among the academic neurosurgery community and is thought to represent a barrier to teaching, ultimately compromising patient care. The authors hypothesize that the introduction of the mandatory resident work-hour restriction corresponds with an overall increase in morbidity rate. METHODS: This study compares the morbidity and mortality rates on an academic neurological surgery service before and after institution of the work-hour restriction. Complications are individually assessed at a monthly divisional conference by neurosurgical faculty and residents. A prospective database was commenced in July 2000 recording all complications, complications that were deemed to be potentially avoidable ("possibly preventable"), and complications that were deemed unavoidable. The incidence of morbidity and mortality from July 2000 to June 2003 is compared with the incidence from July 2003 to June 2006. RESULTS: The overall rate of morbidity and mortality increased from 103 to 114 per 1000 patients treated after institution of the work-hour restriction, although this increase was not statistically significant (χ(2)(1, N = 8546) = 2.6, p = 0.106). The morbidity rate increased from 70 to 89 per 1000 patients treated after institution of the work-hour restriction (χ(2)(1, N = 8546) = 10, p = 0.001). The overall mortality rate was diminished from 32 to 27 per 1000 patients treated after institution of the work-hour restriction (χ(2)(1, N = 8546) = 3.2, p = 0.075). Morbidities considered avoidable or possibly preventable were seen to increase from 56 to 66 per 1000 patients treated (χ(2)(1, N = 8546) = 5.7, p = 0.017). Avoidable or possibly preventable mortalities numbered 3 per 1000 patients treated, and this rate did not change after introduction of the work-hour restriction (χ(2)(1, N = 8546) = 0.08, p = 0.777). CONCLUSIONS: The morbidity rate on a neurological surgery service is increased after implementation of the work-hour restriction. Mortality rates remain unchanged.

Prediction of symptomatic cerebral vasospasm after aneurysmal subarachnoid hemorrhage with an artificial neural network: feasibility and comparison with logistic regression models.

OBJECTIVE: To create a simple artificial neural network (ANN) to predict the occurrence of symptomatic cerebral vasospasm (SCV) after aneurysmal subarachnoid hemorrhage (aSAH) based on clinical and radiographic factors and test its predictive ability against existing multiple logistic regression (MLR) models. METHODS: A retrospective database of patients admitted to a single academic medical center with confirmed aSAH between January 2002 and January 2007 (91 patients) was input to a back-propagation ANN program freely available to academicians on the Internet. The resulting ANN was prospectively tested against two previously published MLR prediction models for all patients admitted the following year (22 patients). The models were compared for their predictive accuracy with receiver operating characteristic (ROC) curve analysis. RESULTS: All models were accurate with their prediction of patients with SCV. The ANN had superior predictive value compared with the MLR models, with a significantly improved area under ROC curve (0.960 ± 0.044 vs 0.933 ± 0.54 and 0.897 ± 0.069 for MLR models). CONCLUSIONS: A simple ANN model was more sensitive and specific than MLR models in prediction of SCV in patients with aSAH. The conception of ANN modeling for cerebral vasospasm is introduced for a neurosurgical audience. With advanced ANN modeling, the clinician may expect to build improved models with more powerful prediction capabilities.

Subarachnoid Hemorrhage Induces Gliosis and Increased Expression of the Pro-inflammatory Cytokine High Mobility Group Box 1 Protein.

Subarachnoid hemorrhage (SAH) following cerebral aneurysm rupture is associated with high rates of morbidity and mortality. Surviving SAH patients often suffer from neurological impairment, yet little is currently known regarding the influence of subarachnoid blood on brain parenchyma. The objective of the present study was to examine the impact of subarachnoid blood on glial cells using a rabbit SAH model. The astrocyte-specific proteins, glial fibrillary acidic protein (GFAP) and S100B, were up-regulated in brainstem from SAH model rabbits, consistent with the development of reactive astrogliosis. In addition to reactive astrogliosis, cytosolic expression of the pro-inflammatory cytokine, high-mobility group box 1 protein (HMGB1) was increased in brain from SAH animals. We found that greater than 90% of cells expressing cytosolic HMGB1 immunostained positively for Iba1, a specific marker for microglia and macrophages. Further, the number of Iba1-positive cells was similar in brain from control and SAH animals, suggesting the majority of these cells were likely resident microglial cells rather than infiltrating macrophages. These observations demonstrate SAH impacts brain parenchyma by activating astrocytes and microglia, triggering up-regulation of the pro-inflammatory cytokine HMGB1.

Safety of microvascular decompression for trigeminal neuralgia in the elderly. Clinical article.

OBJECT: Microvascular decompression (MVD) offers an effective and durable treatment for patients suffering from trigeminal neuralgia (TN). Because the disorder has a tendency to occur in older persons, the risks of surgical treatment in the elderly have been a topic of recent interest. To date, evidence derived from several small retrospective and a single prospective case series has suggested that age does not increase the complication rate associated with surgery. Using a large national database, the authors aimed to study the impact of age on in-hospital complications following MVD for TN. METHODS: Using the Nationwide Inpatient Sample (NIS) for the 10-year period from 1999 to 2008, the authors selected all patients who underwent MVD for TN. The primary outcome of interest was the in-hospital mortality rate. Secondary outcomes of interest were cardiac, pulmonary, thromboembolic, cerebrovascular, and wound complications as well as the duration of hospital stay, total hospital charges, and discharge location. An elderly cohort of patients was first defined as those 65 years of age and older and then redefined as those 75 years and older. RESULTS: A total of 3273 patients who underwent MVD for TN were identified, having a median age of 57 years. Within this sample, 31.5% were 65 years and older and 10.7% were 75 years and older. The in-hospital mortality rate was 0.68% for patients 65 years or older (p = 0.0087) and 1.16% for those 75 years or older (p = 0.0026). In patients younger than 65 years, the in-hospital mortality rate was 0.13% (3 deaths among 2241 patients). As analyzed using the chi-square test (for both 65 and 75 years as the age cutoff) and the Pearson rank correlation coefficient, the risk of cardiac, pulmonary, thromboembolic, and cerebrovascular complications was higher in older patients (that is, those 65 and older and those 75 and older), but the risks of wound complications and CNS infection were not. The risk of any in-hospital complication occurring in a patient 65 years and older was 7.36% (p < 0.0001) and 10.0% in those 75 years and older (p < 0.0001). There was no difference in the total hospital charges associated with age. The duration of the hospital stay was longer in older patients, and the likelihood of discharge home was lower in older patients. CONCLUSIONS: Microvascular decompression for TN in the elderly population remains a reasonable surgical option. However, based on data from a large national database, authors of the present study suggest that complications do tend to gradually increase in tandem with an advanced age. While age does not act as a risk factor in isolation, it may serve as a convenient surrogate for complication rates. The authors hope that this information can be of use in guiding older patients through decisions for the surgical treatment of TN.