The possible impact of cervical stenosis on cephalad neuronal dysfunction.

Earlier observers have speculated on the causal relationships between abnormal CSF circulation and a variety of neurological dysfunctions. Such speculations have been at least partially validated by recent evidence and inquiries contravening the traditional static viewpoint of CSF circulation. More contemporary inquiries establish a number of factors which influence both CSF production and absorption (sleep disturbance, neck position, cerebral metabolism, brain atrophy, medications, etc.). Thus, transient periods of abnormality are possibly mingled with periods of normality. Such episodic alterations suggest that the physiological arrangements which underpin CSF circulation may be in some ways likened to blood pressure alterations, in that long-standing CSF abnormalities may be both unappreciated and gradual, though virulent enough to cause substantial neurological injury. We suggest that cervical stenosis (blocking an important CSF decompressive pathway into the vertebral canal) is among the largely unappreciated causes of abnormal CSF circulation and may play a role in cephalad neuronal dysfunction. Such a blockage is correlated with age and easily assessed by cine MRI study. Indeed, episodic disturbances can diminish CSF cerebral flow circulation increasing deposition in cerebral parenchyma of contrary metabolic products (e.g. beta Amyloid), possibly having a causal influence on senile dementia. Additionally, cervical stenosis, by increasing posterior fossa cerebral pressure, could play a causal role in a number of afflictions, among them sleep apnea, concomitant respiratory and circulatory dysfunction, hypertension, chronic occipital headaches, tinnitus, etc. We further suggest that among those patients with substantial cervical stenosis (extensive enough to block CSF circulation in the cervical area as identified by cine MRI) appropriate comparative clinical studies could be undertaken to demarcate associations with presenile dementia, sleep disturbance and posterior fossa dysfunction. Additionally, we suggest that an intracranial monitoring implant be perfected to chronically monitor both intracranial pressure and CSF flow - a monitoring device comparable to the rather less invasive sphygmometric evaluation of blood pressure. If such speculations prove correct, different therapeutic regimens which might improve outcome could be imagined. Among them better sleep hygiene (to by position maximize CSF flow) and possibly more aggressive operative decompressive intervention to diminish cervical obstruction.

Anxiety's Impact on Length of Stay Following Lumbar Spinal Surgery.

INTRODUCTION: Despite some evidence that anxiety may affect length of stay (LOS), relatively little inquiry exists regarding this in neurosurgical literature. OBJECTIVE: To determine the influence of anxiety on LOS after elective lumbar decompression and fusion (LDF) surgery. METHODS: The medical records of 307 patients who consecutively underwent elective LDF surgery from October 1, 2010, through September 30, 2013, were retrospectively reviewed. Each patient's medications and comorbidities were determined using the medical history. The impact of their medications on LOS was studied using multivariate analysis. Linear regression was also used to assess the relationship between anxiolytic use and LOS. An independent sample t test was used to compare the mean LOS of the group of patients receiving muscle relaxants with that of the group who were not. RESULTS: Those with a diagnosis of anxiety who were taking anxiolytics (n = 32) stayed 1.8 days longer than those with no diagnosis of anxiety and who were not taking anxiolytics (n = 224) after LDF surgery (p = 0.003). Those with a diagnosis of anxiety who were taking anxiolytics (n = 32) stayed 1.9 days longer than those with no diagnosis of anxiety and who were taking anxiolytics (n = 24) after LDF surgery (p = 0.003). CONCLUSION: Our study suggests that those with a diagnosis of anxiety who take medications for that condition have a longer LOS than those with no diagnosis of anxiety and who are not medicated for the condition. This could be because these patients are more vulnerable to states of anxiety when required to be nil per os for 12 hours before surgery.

Randomized double-blind placebo trial of duloxetine in perioperative spine patients.

OBJECTIVE: This study describes a single-site investigation on the effects of a randomized double-blind placebo trial targeting duloxetine added to opioid use (duloxetine + opioid) against a comparator (placebo + opioid) in spine surgery patients, independent of major depression. DESIGN: The double-blind comparator study assessed two groups on opioids: one using duloxetine and the other a placebo. Subjects were administered the respective medication 2 weeks prior to surgery and continued on this for more than 3 months. Subjects were assessed at three times: prior to surgery, 4 weeks postsurgery, and 12 weeks postsurgery. They completed a battery of tests assessing for pain, adjustment, and psychiatric problems. SETTING: Neurosurgical outpatient and inpatient setting. PATIENTS: Sixty-eight patients completed the study. They received one of three types of elective spine surgery. INTERVENTIONS: Subjects were given duloxetine or placebo 2 weeks prior to surgery and continued with the regimen for more than 3 months. OUTCOMES: The primary focus was pain and second on adjustment factors and psychiatric symptoms: depression and anxiety. The amount of opioid use presurgery and postsurgery was also evaluated. RESULTS: There were differences among the groups on Brief Pain Inventory (BPI)-Average, the core pain marker, and BPI-Sleep. Within-subject analyses showed that duloxetine subjects improved significantly from baseline. For function, post-CIBIC and post-Functional Adjustment Questionnaire were significant, favoring duloxetine. Reduction of opioid use was not a factor; both groups' utilization declined. For affect, both groups were significantly improved over time. CONCLUSIONS: Duloxetine seems to improve pain, assist with maintaining function, and reduce intensity of affect.

Preoperative pain intensity and chronicity and postoperative analgesia markers of length of stay in patients undergoing spinal fusion.

INTRODUCTION: Pain medication use is enormous in those looking for relief of chronic back pain. The impact of long-term analgesia use might serve as a marker for prolonged hospitalization due to undertreating postoperative pain, which could ultimately result in higher health care costs. METHODS: We studied preoperative pain intensity and chronicity and the amount of postoperative analgesia as a marker of length of stay (LOS) in patients undergoing spinal fusion. The charts of patients undergoing cervical or lumbar spinal fusion were reviewed, and data on their intensity of pain at admission and length of pain was documented, as was the amount of morphine used. RESULTS: Regression analysis revealed statistical significance only between LOS and surgical site (neck or lumbar spine). It showed no significance between LOS as the dependent variable and preoperative pain parameter, postoperative morphine per kilogram, sex, or age as predictors. CONCLUSION: Postoperative pain management continues to be a challenge because of the need to balance satisfactory analgesia in patients with the fear of adverse effects due to overdosing. This challenge is even greater in patients with long-term narcotic use. Anecdotally, patients undergoing spinal fusion show an inverse relationship between LOS and amount of use of postoperative pain medication. A more extensive scientific review of current postoperative pain control protocols is warranted in patients undergoing spinal fusion.

Preoperative evaluation with FMRI of patients with intracranial gliomas.

Introduction. Aggressive surgical resection constitutes the optimal treatment for intracranial gliomas. However, the proximity of a tumor to eloquent areas requires exact knowledge of its anatomic relationships to functional cortex. The purpose of our study was to evaluate fMRI's accuracy by comparing it to intraoperative cortical stimulation (DCS) mapping. Material and Methods. Eighty-seven patients, with presumed glioma diagnosis, underwent preoperative fMRI and intraoperative DCS for cortical mapping during tumor resection. Findings of fMRI and DCS were considered concordant if the identified cortical centers were less than 5 mm apart. Pre and postoperative Karnofsky Performance Scale and Spitzer scores were recorded. A postoperative MRI was obtained for assessing the extent of resection. Results. The areas of interest were identified by fMRI and DCS in all participants. The concordance between fMRI and DCS was 91.9% regarding sensory-motor cortex, 100% for visual cortex, and 85.4% for language. Data analysis showed that patients with better functional condition demonstrated higher concordance rates, while there also was a weak association between tumor grade and concordance rate. The mean extent of tumor resection was 96.7%. Conclusions. Functional MRI is a highly accurate preoperative methodology for sensory-motor mapping. However, in language mapping, DCS remains necessary for accurate localization.

Shortfalls in published neurosurgical literature.

Expenditure related to neurosurgery has increased unevenly since the early 1990s. In this study we explored the literature by which clinical evidence is obtained to better direct neurosurgical practice. We searched different types of neurosurgery literature and four major neurosurgical procedures (excision of brain lesion, cerebral aneurysm clipping/coiling, discectomy, spine fusion) written in English on PubMed from 1996, the year of its launch, using the keyword "cost". Only a small and static portion of the neurosurgical literature was indexed as level I clinical evidence (randomized controlled trials), with a lack of cost appraisal in the outcome analysis of neurosurgical interventions. By way of rectification, a major increase in funding of grade I studies with cost analysis, and the requirement by peer-reviewed journals of a cost-benefit analysis, would promote the quality of clinical research yielding unquestionable advantage on national healthcare practice.

Shortfalls in pediatric hydrocephalus clinical outcome analysis.

BACKGROUND: In this paper, we used search engine technology to study outcome analysis and cost awareness of child hydrocephalus in the literature. METHODS: The aggregate hospital charges of hydrocephalus treatment procedures for patients <18 years old was extracted from the Nationwide Inpatient Sample (NIS) data. Hydrocephalus literature was probed through the PubMed biomedical search engine. RESULTS: Aggregate hospital charges associated with ventriculo-peritoneal shunting as the principle procedure for patients <18 years old have increased 1.7-fold over a 13-year period to 235.6 million in 2009. Hospital discharges, however, decreased from 3,390 in 1997 to 2,525 in 2009 (25.5% decrease over 13 years). The number of papers in English language indexed by PubMed in relation to child hydrocephalus in humans increased from 81 papers in 1996 to 133 in 2010 (1.6-fold increase), totaling 1,694 over 15 years. Randomized controlled trials published in relation to child hydrocephalus totaled 16 over the same period (0.94% of child hydrocephalus papers). Papers related to child hydrocephalus with "costs and cost analysis" as medical subject heading totaled 13 papers (0.77%). CONCLUSIONS: Over the past 15 years, disappointingly the number of printed child hydrocephalus papers appeared to have only plateaued. Strikingly, only a very small number of these papers were directed toward randomized control studies, the sine qua non of high-grade clinical evidence. Moreover, very few papers make reference to cost analysis or economics in the treatment of hydrocephalus - an issue coming increasingly before the nation at this point.

The role of drains in lumbar spine fusion.

OBJECTIVE: To study the role of drains in lumbar spine fusions. METHODS: The charts of 402 patients who underwent lumbar decompression and fusion (LDF) were retrospectively reviewed. Patients were classified per International Classification of Diseases, 9th Edition (ICD-9) procedure code as 81.07 (lateral fusion, 74.9%) and 81.08 (posterior fusion, 25.1%). The investigators studied the prevalence of drain use in lumbar fusion procedures and the impact of drain use on postoperative fever, wound infection, posthemorrhagic anemia, blood transfusion, and hospital cost. RESULTS: No significant differences in wound infection rates were noted between patients with and without drains (3.5% vs 2.6%, P = 0.627). The difference in postoperative fever rates between patients with and without drains (63.2% vs 52.6%, P = 0.05) was of borderline significance. Posthemorrhagic anemia was statistically more common in patients with drains (23.5% vs 7.7%, P = 0.000). Allogeneic blood transfusion was also statistically more common in the drained group (23.9% vs 6.8%, P = 0.000). Postoperative hemoglobin levels were lower in patients with drains who underwent one-level (9.5 g/dL vs 11.3 g/dL) or two-level (9.3 g/dL vs 10.2 g/dL) spine fusions. In this series in which drains were liberally used, no patient had to return to the operating room because of postoperative hematoma. An increased rate of allogeneic blood transfusion was noticed with posthemorrhagic anemia and drain use. The rate of allogeneic blood transfusion increased from 5.6% in patients without drains or posthemorrhagic anemia to 38.8% in patients with drains and posthemorrhagic anemia as a secondary diagnosis. The use of drains was associated with statistically insignificant increases in length of stay and cost in posterior procedures. Drain use was associated with shorter length of stay and hospital charges in lateral fusions of three or more levels. CONCLUSIONS: Drain use did not increase the risk of wound infection in patients undergoing LDF, but it had some impact on the prevalence of postoperative fever. Drain use was significantly associated with posthemorrhagic anemia and allogeneic blood transfusion. Drain use did not have a significant economic impact on hospital length of stay and charges except in lateral procedures involving three or more levels.

De novo spine surgery as a predictor of additional spine surgery at the same or distant spine regions.

INTRODUCTION: Degenerative spine disorders are steadily increasing parallel to the aging of the population with considerable impact on cost and productivity. In this paper we study the prevalence and risk factors for multiple spine surgery and its impact on cost. METHODS: Data on 1,153 spine surgery inpatients operated between October 2005 and September 2008 (index spine surgery) in regard to the number of previous spine surgeries and location of surgeries (cervical or lumbar) were retrospectively collected. Additionally, prospective follow-up over a period of 2-5 years was conducted. RESULTS: Retrospectively, 365 (31.7%) patients were recurrent spine surgery patients while 788 (68.3%) were de novo spine surgery patients.Nearly half of those with previous spine surgery (51.5%) were on different regions of the spine. There were no significant differences in length of stay or hospital charges except in lumbar decompression and fusion (LDF) patients with multiple interventions on the same region of the spine. Significant differences (P<.05) in length of stay (5.4 days vs. 7.4 days) and hospital charges ($55,477 vs. $74,878) between LDF patients with one previous spine versus those with ≥3 previous spine surgeries on the same region were noted.Prospectively, the overall reoperation rate was 10.4%. The risk of additional spine surgery increased from 8.0% in patients with one previous spine surgery (index surgery) to 25.6% in patients with ≥4 previous spine surgeries on different regions of the spine (including index surgery).After excluding patients with previous spine surgeries on different regions of the spine, 17.2% of reoperated patients had additional spine surgery on a different spine region. The percentage of additional spine surgery on a distant spine region increased from 14.0% in patients with one spine surgery to 33.0% in patients with two spine surgeries on the same region. However, in patients with three or more spine surgeries on the same spine region there were no interventions on a distant spine region during the follow-up period. CONCLUSION: De novo spine surgery is associated with an increased incidence of additional spine surgery at the same or distant spine regions. Large prospective studies with extended follow-up periods and multifaceted cost-outcome analysis are needed to refine the appropriateness of spine surgery.

Higher comorbidity rates in unemployed patients may significantly impact the cost of spine surgery.

Chronic back pain is commonly associated with physical and mental comorbidities, which create a considerable burden on the healthcare system. We examined the differences in comorbidity rates of 619 spinal surgery patients of employment age, and the impact of comorbidity rates on length of hospital stay and cost. The charts of patients aged >25 years and <65 years were reviewed retrospectively. Type of surgery, employment status, comorbidities, length of stay and hospital charges were studied using chi-square, Fisher, Student's t-test, Wilcoxon-Mann-Whitney test and multivariate analysis. The unemployment rate among employment-aged spinal surgery patients was 44.7%. Unemployed patients who underwent any of the three types of surgery (anterior cervical decompression and fusion, lumbar decompression and fusion, and lumbar microdiscectomy [LMD]) stayed longer in hospital but had higher hospital charges in the minimally invasive LMD group only. There were higher rates of some comorbidities in unemployed compared to employed patients: asthma (12.2% vs. 5.9%), coronary artery disease (20.4% vs. 12.8%), diabetes mellitus (58.0% vs. 47.3%), history of coronary artery bypass surgery or stent placement (18.2% vs. 11.6%), hypothyroidism (14.4% vs. 8.2%), knee joint disease (43.1% vs. 33.6%), chronic renal disease (12.9% vs. 2.9%) and opioid (55.2% vs. 45.9%) antidepressant (37.0% vs. 25.3%) anxiolytic (16.0% vs. 8.9%) use. Charlson comorbidity scores were significantly different (p<0.001) between unemployed (1.72 ± 1.90) and employed patients (1.03 ± 1.55). Multivariate analysis showed that a history of coronary artery bypass/stent procedure, chronic renal disease or preoperative opioid use had a significant impact on length of stay and hospital charges in unemployed spine surgery patients. Thus, unemployment in spinal surgery candidates is associated with higher comorbidity rates with a significant impact on healthcare cost. More research is needed into the relationship between unemployment and consumption of healthcare resources.

The effect of age and body mass index on cost of spinal surgery.

Complex shifts in demography combined with drastic advancements in spinal surgery have led to a steep increase in often expensive spinal interventions in older and obese patients. A cost analysis, based on hospital charges, was performed retrospectively on the spinal surgery of 787 randomly selected patients who were operated at The Medical Center of Central Georgia, a large urban hospital in Central Georgia. The types of surgery included anterior cervical decompression and fusion (ACDF), lumbar decompression and fusion (LDF), and lumbar microdiscectomy (LMD). The distribution of patient age followed a Gaussian form. The peak age for patients was 50-59 years (28.8%), and there was no statistical difference in age between men and women. The body mass index (BMI) differed (p<0.01) between males (28.86 kg/m(2); range: 18-47 kg/m(2)) and females (30.69 kg/m(2); range: 17-58 kg/m(2)). The BMI data did not follow a Gaussian distribution for either gender. The hospital cost for spinal surgery increased with age except for male patients who underwent ACDF. For male patients who underwent LDF, the increase in hospital cost was statistically significant between the 40-49-year and the ≥ 70-year age groups. Univariate analysis with type of surgery as a covariate showed that age was a significant determinant of hospital cost (p=0.000), and BMI was not (p=0.110); however, the interaction between age and BMI was significant (p=0.000). Older patients undergoing spinal surgery had lower BMI, more so in males (r=-0.047, p=0.426) than in females (r=-0.038, p=0.485). There were linear trends in all gender-spinal surgery categories between age, BMI and hospital cost. Older female patients who underwent LDF tended to have a lower BMI but higher hospital cost, confirming that age was more important than BMI in determining hospital cost in these patients. The increments in cost of spinal surgery in relation to age especially and BMI were, nevertheless, small. We believe that spinal surgery in the elderly should be viewed as a public investment, as the modern concept of retirement involves people working intermittently up to their 80s. Thus, where clinical research on medical costs is to be conducted, cost analysis needs to be expanded to include returns to government in the form of taxes.

Postoperative fever discharge guidelines increase hospital charges associated with spine surgery.

BACKGROUND: Postoperative fever is a common sequel of spine surgery. In the presence of rigid nationally mandated clinical guidelines, fever management may consume more health care resources than is reasonably appropriate. OBJECTIVE: To study the relationship between postoperative fever, infection rate, and hospital charges in a cohort of spine surgery patients. METHODS: We retrospectively reviewed 578 spine surgery patients (lumbar microdiskectomy [LMD], anterior cervical decompression and fusion [ACDF], and lumbar decompression and fusion [LDF]). Differences in length of stay and hospital charges as well as risk factors and correlation with infection and readmission rates were studied. RESULTS: Postoperative fever occurred in 41.7% of all spine surgery patients and more often in LDF patients (77.2%). Type of surgery was the most important variable affecting the prevalence of postoperative fever. Significant differences in length of stay were elicited between patients with and without postoperative fever in the ACDF and LMD groups and in hospital cost in the LMD group. The average length of stay was 2.41 vs 4.47 (P < .01) in the LMD group, 1.67 vs 2.80 (P < .05) in the ACDF group, and 5.03 vs 5.65 (P > .05) in the LDF group. The average hospital charges were $16 261 vs $22 166 (P < .01) in the LMD group, $26 021 vs $29 125 (P > .05) in the ACDF group, and $53 627 vs $53 210 (P > .05) in the LDF group. Obesity, female sex, and ≥102°F postoperative temperature were the most significant predictors of infection. Delayed discharge referable to postoperative fever did not seem to influence the infection readmission rate. CONCLUSION: Postoperative fever in spine surgery patients is associated with a delay in patient discharge and increases in hospital charges. Postoperative fever discharge guidelines should be regularly and publicly subjected to appropriate cost-benefit analysis.

Economic impact of comorbidities in spine surgery.

OBJECT: Comorbidities in patients undergoing spine surgery may reasonably be factors that increase health care costs. To verify this hypothesis, the authors conducted the following study. METHODS: Major comorbidities and age-adjusted Charlson Comorbidity Index scores were retrospectively analyzed for 816 patients who underwent spine surgery at the authors' institutions between 2005 and 2008, and treatment costs (hospital charges) were assessed with the help of statistical software. The sample was collected by a nonmedical staff (hired at the beginning of 2006). Patients underwent one of the three most common types of spine surgery: lumbar microdiscectomy (20.5%), anterior cervical decompression and fusion (ACDF; 60.3%), or lumbar decompression and fusion (LDF; 19.2%). Patients were nearly equally divided by sex (53% were female and 47% male), and 78% were Caucasian versus 21% who were African American; the rest were of mixed or unidentified race. The average age was 54 years, with an SD of ± 14 years. RESULTS: There were significant differences in the prevalence of major comorbidities between male and female and between severely obese and nonseverely obese patients. The impact of comorbidities on the cost of spine surgery was more prominent in older patients, and an additive effect from some comorbidities was recorded in various types of spine surgery. For instance, in the ACDF group, female patients with both severe obesity and diabetes mellitus (DM) had significantly higher hospital charges than those with only one or neither of these conditions ($34,943 for both severe obesity and DM vs $25,633 for severe obesity only; $25,826 for DM only; and $25,153 for those with neither condition [p < 0.05]). In the LDF group, female patients with both DM and a history of depression had significantly higher hospital charges than those with only one or neither of these conditions ($65,782 for both DM and depression vs $53,504 for DM only; $55,990 for depression only; and $52,249 for those with neither condition [p < 0.05]). A significant difference was also found in hospital cost ($16,472 [p < 0.01]; 32% increase over baseline) in the LDF group between patients with the lowest and highest scores on the Charlson Index. CONCLUSIONS: Comorbidities additively increase hospital costs for patients who undergo spine surgery, and should be considered in payment arrangements.

The Relationship between Pulmonary Dysfunction and Age in Vasospasm Patients Receiving Triple H Therapy.

BACKGROUND AND INTRODUCTION: Triple H therapy is conventionally used to treat vasospasm following sub-arachnoid hemorrhage (SAH) but can sometimes have side effects. In order to investigate pulmonary complications in SAH patients and relationship with age we conducted the following study. METHODS: The charts of 121 sub-arachnoid hemorrhage patients who underwent clipping or coiling of an aneurysm were retrospectively reviewed. The diagnosis of vasospasm was documented based on Doppler and angiographic findings. All patients with vasospasm received the standard Triple H therapy (hematocrit 33-38%, central venous pressure 10-12 mmHg, systolic blood pressure 160-200 mmHg). We studied intravenous intake, artificial ventilation, hypoxemia/pulmonary edema, postoperative fever, pneumonia and death rates as outcome variables. RESULTS: Sixty five patients developed vasospasm (15 mild, 23 moderate, 27 severe). These were significantly younger than non-vasospasm patients (51 years vs. 61 years, p=0.004). The average daily intravenous input was 1,730 cc in novasospasm patients, 2,123 cc in the mild vasospasm group, 2,399 cc in the moderate vasospasm group, and 3,040 cc in the severe vasospasm group. Younger patients with moderate to severe vasospasm received more fluids than older patients. Ten patients (8.3%) developed hypoxemia or pulmonary edema. No patient developed hypoxemia/pulmonary edema in the mild vasospasm group and the rates did not show a trend and were not statistically different (7.1%, 0.0%, 13.0%, 11.1%, p>0.05) between vasospasm and non-vasospasm groups. Likewise, postoperative fever and pneumonia rates were not different between the vasospasm and non-vasospasm groups. Using the mean age as a threshold, pulmonary-related complications including death rates tended to be higher in the older group. The rates of postoperative ventilation (30.8% vs. 57.1%, P<0.01) and hypoxemia/pulmonary edema (3.1% vs. 14.3%, P<0.05) rates were statistically higher in the older group. Patients who developed hypoxemia/pulmonary edema in the vasospasm group tended to be younger than those who developed hypoxemia/pulmonary edema in the non-vasospasm group. CONCLUSION: Younger patients are at a higher risk of developing vasospasm than older patients possibly referable to vessel elasticity and reactive sensitivity factors. Likewise, patients who developed hypoxemia/pulmonary edema in the vasospasm group were younger than in the non-vasospasm group possibly secondary to fluid overload from triple H therapy.

Computational modeling of HHH therapy and impact of blood pressure and hematocrit.

BACKGROUND: After an aneurysmal subarachnoid hemorrhage, cerebral microcirculatory changes occur as a result cerebral vasospasm. The objective of this study is to investigate, with a computational model, how various degrees of vasospasm are influenced by increasing the mean blood pressure and decreasing the blood viscosity. METHODS: Using ANSYS CFX software, a computational model was constructed to simulate steady-state fully developed laminar blood flow through a rigid wall system consisting of the internal carotid artery (ICA), anterior cerebral artery, posterior cerebral artery, and middle cerebral artery (MCA). The MCA was selected for the site of a single acute vasospasm. Five severities of vasospasm were studied: 3 mm (normal), 2.5, 2, 1.5, and 1 mm. The ICA was assumed to have a constant inlet flow rate of 315 mL/min. The anterior cerebral artery and posterior cerebral artery were assumed to have constant outlet flow rates of 105 mL/min and 30 mL/min, respectively. The MCA was assumed to have a constant outlet pressure of 92 mL/min. Two different hematocrits, 45% and 32%, were simulated using the models. RESULTS: For a hematocrit of 45, the mean ICA inlet pressure required to pump blood through the system was 104 mm Hg for the 3-mm diameter MCA and 105, 108, 116, and 158 mm Hg for vasospasm diameters of 2.5, 2, 1.5, and 1 mm, respectively. For a hematocrit of 32, the mean ICA inlet pressure required was 102, 103, 105, 113, and 152 mm Hg, respectively. CONCLUSIONS: The MCA required a large increase in mean ICA inlet pressure for vasospasm diameters less than 1.5 mm, which suggests that for vasospasms more than 50% diameter reduction, the blood pressure must be increased dramatically. Decreasing the hematocrit had minimal impact on blood flow in a constricted vessel.

Prevalence of previously unknown elevation of glycosylated hemoglobin in spine surgery patients and impact on length of stay and total cost.

BACKGROUND: Elevated levels of glycosylated hemoglobin (HbA1c) among spine surgery patients may have an impact on length of stay (LOS) and healthcare cost. MATERIALS AND METHODS: We retrospectively reviewed the charts of 556 spine surgery patients who underwent 1 of 3 types of surgery: lumbar microdiscectomy (LMD), anterior cervical decompression and fusion (ACDF), and lumbar decompression and fusion (LDF). Information was collected about their diabetes mellitus (DM) history and HbA1c levels. We used HbA1c 6.1% as the screening cutpoint. Percentages of nondiabetic patients, those with subclinical elevation of HbA1c and those with already known DM were calculated and statistical analysis was applied. RESULTS: After excluding the small group of well-controlled DM (n = 14), 72.4% of patients were nondiabetic, 14.3% were subclinical patients with previously unknown HbA1c elevation, and 13.3% were already known, confirmed DM patients. There were significant differences in the LDF group between the "No DM" and "Subclinical" groups (P < 0.05) in terms of cost and LOS (P < 0.05). Age and body mass index (BMI) were very significant predictors of total cost in spine surgery patients (P 0.05) in determining cost. CONCLUSIONS: There is a significant segment of spine surgery patients who were unaware of their elevated HbA1c status before their preoperative visit. These patients seem to utilize more healthcare resources, which is especially evident in the LDF group. We believe that HbA1c should be considered in the routine preoperative workup of spine surgery patients.

Interaction of age and opioid dependence on length of hospital stay for spine surgery patients.

Clinical information suggests that opioid dependence is a major contributor to poor outcomes involving health status and to increased length of stay in hospital settings. Before spine surgery, 150 patients who were using an opioid medication for pain relief were interviewed using the six World Health Organization (WHO) guidelines for the diagnosis of opioid dependence. Three groups were defined: opioid-dependent, nonopioid-dependent, and a subclinical group. Results revealed an average of 20% of patients (N = 30) who met the WHO criteria for the diagnosis of opioid dependence. There were significant positive correlations between age and number of positive WHO criteria, length of stay, and time under surgery. Length of stay was significantly higher for the older age group (> 55 yr.). ANCOVA analysis using two opioid dependence groups (+ and -) and age group as independent variables affecting length of stay, after controlling for type of surgery, pain intensity, and number of previous spine surgeries, revealed that effects of opioid dependence status and age were significant but their interaction was not. Age did add length of stay independently of opioid dependence status; older adults remain in the hospital longer for various reasons probably associated with comorbidities.

Serum and cerebrospinal fluid C-reactive protein levels as predictors of vasospasm in aneurysmal subarachnoid hemorrhage. Clinical article.

OBJECT: Cerebral vasospasm is a common and potentially devastating complication of aneurysmal subarachnoid hemorrhage (aSAH). Inflammatory processes seem to play a major role in the pathogenesis of vasospasm. The C-reactive protein (CRP) constitutes a highly sensitive inflammatory marker. The association of elevated systemic CRP and coronary vasospasm has been well established. Additionally, elevation of the serum CRP levels has been demonstrated in patients with aSAH. The purpose of the current study was to evaluate the possible relationship between elevated CRP levels in the serum and CSF and the development of vasospasm in patients with aSAH. METHODS: A total of 41 adult patients in whom aSAH was diagnosed were included in the study. Their demographics, the admitting Glasgow Coma Scale (GCS) score, Hunt and Hess grade, Fisher grade, CT scans, digital subtraction angiography studies, and daily neurological examinations were recorded. Serial serum and CSF CRP measurements were obtained on Days 0, 1, 2, 3, 5, 7, and 9. All patients underwent either surgical or endovascular treatment within 48 hours of their admission. The outcome was evaluated using the Glasgow Outcome Scale and the modified Rankin Scale. RESULTS: The CRP levels in serum and CSF peaked on the 3rd postadmission day, and the CRP levels in CSF were always higher than the serum levels. Patients with lower admission GCS scores and higher Hunt and Hess and Fisher grades had statistically significantly higher levels of CRP in serum and CSF. Patients with angiographic vasospasm had higher CRP measurements in serum and CSF, in a statistically significant fashion (p < 0.0001). Additionally, patients with higher CRP levels in serum and CSF had less favorable outcome in this cohort. CONCLUSIONS: Patients with aSAH who had high Hunt and Hess and Fisher grades and low GCS scores showed elevated CRP levels in their CSF and serum. Furthermore, patients developing angiographically proven vasospasm demonstrated significantly elevated CRP levels in serum and CSF, and increased CRP measurements were strongly associated with poor clinical outcome in this cohort.

Causes and risk factors for postoperative fever in spine surgery patients.

Postoperative fever is a common dilemma faced by neurosurgeons. To study this problem, we prospectively collected patients who developed fever after spine surgery during the academic year 2007-2008 for whom the internist's consultation was requested. Eighty-five (85) patients were identified, of which 17 had an identifiable infectious cause for their febrile reaction (20%) - fever was attributed to urinary tract infection in 8 cases, pneumonia in 5 cases, wound infection in 3 cases (all lumbar), and cholecystitis in 1 case. The remaining 68 patients (80%) had no definitive diagnosis and fever was attributed to a peripheral venous line which, in this case, was replaced or discontinued. In 32 (37.6%) of the patients, the fever developed on postoperative day (POD) 2 or later. There was no statistically significant relationship between day of fever appearance and whether the fever was due to definite infection (P = 0.737). Comparing the basic group with another group of 456 spine surgery patients from 2006-2007 who might or might not have developed fever postoperatively using ANOVA, we found a significant difference in age (P = 0.011) and a very significant difference in hemoglobin level (P = 0.000) and HbA1c level (P = 0.000), but not in body mass index (BMI) (P = 0.289). Thus, most of the postoperative fever cases after spine surgery have no identifiable infectious focus and develop mainly in older patients with anemia and inadequately controlled HbA1c. A meticulous investigation of the source of fever including laboratory and radiological studies remains essential. Early mobilization is recommended for individuals undergoing lower spine surgery in order to decrease bacterial contamination from the gluteal cleavage.