Is increased uric acid a risk factor or a defensive response? The Campania Salute Network.

BACKGROUND AND AIMS: Circulating uric acid (UA) is positively associated with body mass index (BMI), blood glucose, blood pressure (BP), markers of inflammation, and altered lipid profile. UA has also anti-oxidative properties which might be beneficial for cardiovascular (CV) system. It is still debated whether or not UA is independently associated with increased CV morbidity and/or mortality. METHODS AND RESULTS: We studied prognostic impact of UA in 8833 hypertensive adults (mean age 53 ± 12 yrs, 3857 women) from the Campania Salute Network, without prevalent CV disease and more than stage 3 CKD. We calculated standardized UA Z-score, adjusted for age, sex, glomerular filtration rate, and BMI. Low and high UA and UA Z-score quartiles were compared to the 2 middle quartiles assumed to be "normal". Prevalence of obesity and diabetes was higher in low and high than in normal UA Z-score group (all p < 0.001). Systolic BP, left ventricular mass, carotid intima thickness were significantly higher and ejection fraction was reduced in the presence of high UA Z-score (all p < 0.001). Over 33-months average follow-up, incident major CV end-points (MACE) were not significantly different among low, normal and high UA or UA Z-score. In the latter analysis, however, incident MACE tended to be more frequent in the low than the high UA Z-score. Despite the results of multivariable analyses, the effect of less aggressive therapy in low UA Z-score cannot be excluded with certainty. CONCLUSION: In treated hypertensive patients, high levels of UA normalized for major biological determinants do not independently predict CV outcome. CLINICALTRIALS. GOV IDENTIFIER: NCT02211365.

Low-lipid diet reduces frequency and severity of acute migraine attacks.

BACKGROUND AND AIM: There is uncertainty regarding the prevention of migraine crises by changing the lifestyle of patients. The aim of this randomized, crossover intervention trial was to evaluate the effects of a low lipid intake on the incidence and severity of migraine crises, in comparison to a diet with moderate lipid intake. METHODS AND RESULTS: After a 2-month run-in when patients received preventive medication but were left on their habitual diet, a low-lipid or a normal-lipid diet was randomly prescribed for 3 months and thereafter diets were crossed over for the following 3 months. Headache was diagnosed based on the International Classification of Headache Disorders (IHCD) III criteria. The number and severity of attacks were assessed using a self-reported calendar. Adherence to the diet was assessed by a food frequency questionnaire. An analysis was performed on the 83 episodic or chronic migraineurs (63 female and 20 male), in the age range of 18-57 years, who completed both intervention periods. Obese subjects had a significantly higher number of attacks than those overweight or with normal body weight (24.7 ± 8, 16.3 ± 12, and 15.6 ± 11, respectively, p < 0.03) with a significant relationship between the body mass index (BMI) and the number of monthly attacks (r = 0.238, p < 0.03). The number (2.9 ± 3.7 vs. 6.8 ± 7.5, p < 0.001) and severity (1.2 + 0.9 vs. 1.7 ± 0.9, p < 0.01) of attacks significantly decreased during both intervention periods, with a significant difference in favour of the low-lipid diet. CONCLUSIONS: In this group of patients, the low-lipid diet significantly affected the number and severity of migraine attacks in comparison to a normal-lipid diet. ClinicalTrials.gov Identifier: NCT 01917474.

Type of myocardial infarction presentation in patients with chronic kidney disease.

BACKGROUND AND AIM: Association of coronary and renal disease has been frequently found in epidemiological studies. Whether ECG-graphic presentation of myocardial infarction [S-T Elevated MI (STEMI) or Non S-T Elevated MI (NSTEMI)] is related to the degree of renal dysfunction is still unclear. METHODS AND RESULTS: We examined 146 patients with acute myocardial infarction, consecutively entering the Coronary Care Unit of our ward. At entry, patients underwent clinical, ECG-graphic and echocardiographic examination, and blood samples were withdrawn for cardiac markers and general biochemistry. GFR was calculated using the CKD-EPI equation. STEMI was found in 71 cases and NSTEMI in 75 cases. Renal function was normal in 61 patients (stage 1), mildly impaired (<90 mL/min/1.73 m(2) and ≥ 60 mL/min/1.73 m(2)) in 60 (stage 2) and moderately to severely impaired (GFR <60 mL/min/1.73 m(2)) in 25 cases (stages 3-4). Patients were, thereafter, clustered into two groups (stages 1-2 and stages 3-4). Compared to stage 1-2 subjects, stages 3-4 patients were older, were more likely to be diabetic and had more frequently previous cardiovascular diseases. The probability of presentation of NSTEMI for stage 3-4 patients was 4-fold greater than for stage 1-2 patients (p = 0.02). CONCLUSIONS: These data support the evidence that 1) NSTEMI is associated with more severe kidney dysfunction, likely due to more severe and/or longer lasting exposition to risk factors; 2) cardiac and renal impairment are strongly associated. ClinicalTrials.gov Identifier: NCT01636427.

Serum uric acid does not predict incident metabolic syndrome in a population with high prevalence of obesity.

AIM: To evaluate whether uric acid (UA) predicts 4-yr incidence of metabolic syndrome (MetS) in non-diabetic participants of the Strong Heart Study (SHS) cohort. METHODS AND RESULTS: In this population-based prospective study we analyzed 1499 American Indians (890 women), without diabetes or MetS, controlled during the 4th SHS exam and re-examined 4 years later during the 5th SHS exam. Participants were divided into sex-specific tertiles of UA and the first two tertiles (group N) were compared with the third tertile (group H). Body mass index (BMI = 28.3 ± 7 vs. 31.1 ± 7 kg/m(2)), fat-free mass (FFM = 52.0 ± 14 vs. 54.9 ± 11 kg), waist-to-hip ratio, HOMA-IR (3.66 vs. 4.26), BP and indices of inflammation were significantly higher in group H than in group N (all p < 0.001). Incident MetS at the time of the 5th exam was more frequent in group H than group N (35 vs. 28%, OR 1.44 (95% CI = 1.10-1.91; p < 0.01). This association was still significant (OR = 1.13, p = 0.04) independently of family relatedness, sex, history of hypertension, HOMA-IR, central adiposity and renal function, but disappeared when fat-free mass was included in the model. CONCLUSIONS: In the SHS, UA levels are associated to parameters of insulin resistance and to indices of inflammation. UA levels, however, do not predict incident MetS independently of the initial obesity-related increased FFM.

Cardiometabolic risk in overweight subjects with or without relative fat-free mass deficiency: the Strong Heart Study.

BACKGROUND AND AIM: Sarcopenia is a condition mainly due to loss of fat-free mass (FFM) in elderly individuals. RFFMD, however, is also frequent in obese subjects due to abnormal body composition. Objective of this study was to evaluate the impact of relative fat-free mass deficiency (RFFMD) on cardiometabolic (CM) risk in obese normoglycemic individuals. METHODS AND RESULTS: Overweight/obese American Indians from the Strong Heart Study population, without diabetes and with FBG ≤ 110 mg/dL and with GFR >60 mg/mL/1.73 m(2) were selected for this analysis (n = 742). RFFMD was defined on the basis of a multivariable equation previously reported. Fasting glucose and 2 h-OGTT were measured together with urine albumin/creatinine excretion, laboratory and anthropometric parameters. In addition to lower FFM and greater adipose mass, participants with RFFMD had higher body mass index, waist circumference, C-reactive protein, fibrinogen, insulin resistance and urinary albumin/creatinine than participants with normal FFM (all p < 0.001); they also had a greater prevalence of hypertension, impaired glucose tolerance (IGT) or OGTT-diabetes than participants with normal FFM (all p < 0.003) and a near 2-fold greater probability of significant proteinuria (p < 0.01). RFFMD was more frequent in women than in men: significant sex-RFFMD interactions were found for BMI and waist circumference (both p < 0.0001). CONCLUSIONS: RFFMD in overweight/obese normoglycemic individuals is associated with greater probability of hypertension, abnormalities of glucose tolerance and proteinuria. Assessment of RFFRMD might, therefore, help stratifying cardiometabolic risk among normoglycemic individuals with overweight/obesity.

The presacral retroperitoneal approach for axial lumbar interbody fusion: a prospective study of clinical outcomes, complications and fusion rates at a follow-up of two years in 26 patients.

The presacral retroperitoneal approach for axial lumbar interbody fusion (presacral ALIF) is not widely reported, particularly with regard to the mid-term outcome. This prospective study describes the clinical outcomes, complications and rates of fusion at a follow-up of two years for 26 patients who underwent this minimally invasive technique along with further stabilisation using pedicle screws. The fusion was single-level at the L5-S1 spinal segment in 17 patients and two-level at L4-5 and L5-S1 in the other nine. The visual analogue scale for pain and Oswestry Disability Index scores were recorded pre-operatively and during the 24-month study period. The evaluation of fusion was by thin-cut CT scans at six and 12 months, and flexion-extension plain radiographs at six, 12 and 24 months. Significant reductions in pain and disability occurred as early as three weeks postoperatively and were maintained. Fusion was achieved in 22 of 24 patients (92%) at 12 months and in 23 patients (96%) at 24 months. One patient (4%) with a pseudarthrosis underwent successful revision by augmentation of the posterolateral fusion mass through a standard open midline approach. There were no severe adverse events associated with presacral ALIF, which in this series demonstrated clinical outcomes and fusion rates comparable with those of reports of other methods of interbody fusion.

Metabolic syndrome and left ventricular hypertrophy in a general population. Results from the Gubbio Study.

Aims of this study were to investigate the prevalence of metabolic syndrome (MS), diagnosed according to the International Diabetes Federation (IDF) criteria and its relationship with echocardiographic parameters of cardiac structure and function. The study was performed in 707 subjects, age 45-54 years, of the Gubbio Population Study who underwent a comprehensive examination including measurement of body size, blood pressure (BP) and heart rate, 12-lead electrocardiogram, Doppler echocardiography, standardized blood and urine laboratory tests. One hundred and fifty-three subjects were found to have MS, which was more frequent among hypertensive patients than normotensive controls (36.2 vs 13.7%, P<0.001). Apart from visceral obesity present in all subjects by definition according to the IDF criteria, high levels of BP (>130/85 mm Hg) and triglycerides (>or=150 mg/dl) were the most frequently observed components of the syndrome, since their prevalence averaged 75% of those with the syndrome. Left ventricular mass (95.6+/-22 vs 86.4+/-22 g/m(2); P<0.001) and prevalence of left ventricular hypertrophy were increased in the subgroup with MS. Waist circumference, BP and blood glucose were the components of the syndrome with stronger impact on cardiac mass. An early impairment of the diastolic function was detected in this subgroup with a reduction of the early-to-late diastolic filling (0.91+/-0.17 vs 0.99+/-0.23, P<0.001). The results of the present study indicate that MS is frequent in middle-aged general population, particularly in subjects with arterial hypertension. The syndrome is associated to the increase in ventricular mass and the early impairment of diastolic function.

Effects of biomedical sterilization processes on performance characteristics of MEMS pressure sensors.

The effects of steam and gamma sterilization on the performance of bulk-micromachined pressure sensors were investigated using a variable pressure setup. Commercially available piezoresistive MEMS (microelectromechanical systems) pressure sensor die were characterized prior and subsequent to sterilization over a 0-500 Torr pressure range. The effects of sterilization were examined as changes in sensor output voltage (DeltaV) at various applied pressures. For steam sterilization, DeltaV decreased with applied pressure ranging from +0.27 mV at 100 Torr to -0.14 mV at 500 Torr. In contrast, the corresponding values for gamma-sterilized sensors were lower, decreasing from +0.01 mV 100 Torr to -0.06 mV at 500 Torr. The increased variation in DeltaV for the steam-sterilized sensors was attributed to the formation of an oxide film, which was confirmed using energy dispersive X-ray (EDX) spectroscopy. Statistical analysis revealed that the effect of both sterilization procedures on sensor performance was insignificant.

Cardiac structure and function and arterial circulation in hypertensive patients with and without metabolic syndrome.

High blood pressure (BP) is one of the crucial determinants of the metabolic syndrome (MS). The extent to which MS, diagnosed according to the criteria of the International Federation of Diabetes, impacts on cardiovascular organ damage, independently of BP, is debated. Three hundred and forty hypertensive patients and 100 normotensive controls underwent the following procedures: (1) physical examination and resting BP measurements, (2) 24 h ambulatory BP monitoring, (3) laboratory routine examination, (4) echocardiography, (5) carotid ultrasonography and (6) ankle-brachial BP index. The syndrome was found in 104 of the 340 hypertensive patients (30.6). In comparison to those without MS, those with MS had significantly higher prevalence of left ventricular (LV) hypertrophy by mass/height(2.7) criteria (46 vs 42%, P<0.01) but not by LV mass/body surface criteria (30 vs 31%); the ratio between early-to-late peak velocities of the LV filling waves (E/A) was higher (E/A=0.99+/-0.14 vs 0.89+/-0.15, P<0.01) and left atrium was larger (3.8+/-0.3 vs 3.5+/-0.5 cm, P<0.01). Both hypertensive groups had significantly greater LVM and carotid intima-media thickness than normotensives, without between-group-difference. In this hypertension outpatient clinic almost one-third hypertensive patients have MS. They show a deterioration in structure and function of the heart in comparison to hypertensive patients without MS, but no difference was detected in the carotid and peripheral arterial circulation.

Improvement of cardiovascular risk profile in an elderly population of low social level: the ICON (Improving Cardiovascular risk profile in Older Neapolitans) study.

Older age and low socio-economic conditions are associated with poor control of cardiovascular risk factors (RFs). We assessed the prevalence and awareness of cardiovascular RFs in 503 elderly outpatients of low social status attending two public Internal Medicine clinics in Naples, and studied the interaction of education and employment level with risk profile. The therapeutic intervention was oriented to improve patients' motivation through a positive patient-physician relationship, in keeping with the current guidelines for hypertension. The effect of treatment was evaluated by comparing retrospectively the level of cardiovascular RFs at baseline and at the last follow-up examination performed within 31 October 2005. Only 33.3% of patients (age=68+/-6 years) had attended primary school. Overall (current or previous) employment level was also low. Obesity, hypertension and dyslipidaemia were present in most patients, diabetes in 17.3% of them. In all 8.0% of hypertensives, 16.1% of diabetics and 24.7% of dyslipidaemiacs were unaware of their diseases. Cardiovascular risk profile was worse at lower educational and employment levels. Odds ratios for the metabolic syndrome were 0.28 (95% confidence interval (CI)=0.15-0.52) and 0.35 (0.20-0.62) in the most qualified of three education and employment groups, respectively, compared to the lowest ones. The level of all cardiovascular RFs was effectively reduced during treatment. Control rate of most RFs improved significantly (for hypertension, from 12.8 to 36.5%, P<0.001). These patients had a high prevalence of cardiovascular RFs, which correlated with their educational and work activity levels. Awareness of their health status was unsatisfactory. Treatment, specifically addressing patient-physician relationship, favourably affected cardiovascular risk profile.

Effects of different dietary protein intakes on body composition and vascular reactivity.

OBJECTIVE: To assess the effects of a diet rich in protein of animal origin in comparison to one with a protein intake of about 15% of the total daily calories on body composition and arterial function. DESIGN: Randomized prospective study with parallel groups. Body weight (BW), blood pressure (BP), main parameters of carbohydrate and lipid metabolism, body mass composition by bioelectrical impedance analysis, forearm blood flow at rest and in the postischaemic phase by strain gauge plethysmography and flow-mediated dilation of the brachial artery by echography were measured at baseline and after 6 months of the dietary intervention. SUBJECTS: In total, 15 clinically healthy male volunteers, regularly performing a mixed training three times weekly for 90 min. INTERVENTION: The participants were randomly prescribed a diet with high (1.9 g/kg BW) or normal (1.3 g/kg BW) protein content. STATISTICAL ANALYSIS: Differences between means were evaluated by the t-tests for paired or unpaired data and by one way analysis of variance. The strength of correlation between variables was investigated by bivariate Pearson correlation. RESULTS: Serum cholesterol significantly decreased with both diets in comparison to baseline values, whereas BW was slightly but significantly reduced only by the high-protein (HP) diet. No change was detected in BP and the other metabolic parameters. Body mass composition was not significantly modified by either diet. On the other hand, postischaemic flow-mediated dilation of the brachial artery was enhanced by the sole normal protein (NP) diet, whereas no change in the forearm blood flow, both at rest and in the postischaemic phase, was detected. CONCLUSIONS: These preliminary results indicate that HP diet was found to be not useful in increasing the muscle mass in comparison to a NP intake. In contrast to this, the latter diet seems to enhance the endothelial function of the arterial vessels with a more pronounced dilatation of the lumen in response to the increase in blood flow.

Arterial hypertension increases left ventricular mass: role of tight blood pressure control.

In middle-age hypertensives from the Gubbio Population Study, we evaluated the relationship between blood pressure (BP) control over a long time and the prevalence of left ventricular hypertrophy (LVH). A population survey was performed in 1982-1985 and repeated in 1989-1992. During the second survey, subjects in the age range 40-60 years were invited to undergo an M-mode echocardiographic examination. A total of 487 subjects who participated in both surveys are included in the present analysis. Some of them (294) were normotensive (Group 1), 110 were hypertensive but had never taken antihypertensive drugs (Group 2), 47 hypertensives on drugs were in good BP control (Group 3) and 36 hypertensives on drugs had uncontrolled hypertension (Group 4). BP values at the 1989-1992 examination were, respectively, 122/77, 145/86, 124/78 and 153/91 mmHg, while 7 years earlier were 122/77, 133/84, 136/85 and 152/95 mmHg. Despite normal BP levels in Group 3, left ventricular mass index (LVMi, g/m(2.7)) was greater than in normotensives (42.4+/-10, 46.6+/-13, 47.0+/-10, 51.9+/-15 g/m(2.7)). Accordingly, the prevalence of LVH (LVMi >51 g/m(2.7)) was 18, 26.4, 36.7 and 50% in groups 1-4, respectively. The 193 hypertensives were, thereafter, divided according to BP control (ie <140/90 mmHg) on both surveys (1983-1985 and 1989-1992): 27 hypertensives with optimal BP levels on both visits also had a ventricular mass similar to normotensives and significantly lower than the other hypertensives (LVMi 44.6+/-11.6 vs 48.5+/-13.2, P<0.001). In conclusion, these findings indicate that hypertensive patients with BP values at levels similar to those in normotensives for a long period do not increase their left ventricular mass in comparison to subjects with normal BP levels.

Silicon dermabrasion tools for skin resurfacing applications.

Miniature abrasion tools for potential skin resurfacing applications are created using microelectromechanical systems (MEMS) fabrication technology. The abrading microstructures are formed on silicon wafers by a bulk micromachining process based on isotropic xenon difluoride etching. The micromachined abraders (microdermabraders) are packaged and applied to human cadaveric skin to assess abrasion quality. Plastic (acrylic) microreplicated structures, non-coated and aluminum-coated versions, are also used in a similar fashion. Non-textured silicon and plastic samples are used as study controls. Dermabraded and intact skin regions are analyzed qualitatively and quantitatively by light microscopy, image processing techniques, and histology. The microdermabraders exhibit a cleaner, more uniform abrading pattern on the cadaveric skin compared to the plastic microreplicated structures. Furthermore, the microdermabraders provide a consistently uniform cut through the epidermal layer, leaving little debris and minimal pitting. In contrast, the plastic microreplicated structures exhibit non-uniform abrading patterns and leave behind more debris and eccentric pits. The results suggest micromachined dermabraders can successfully abrade fine dermatological flaws in human skin.

Clinic and ambulatory pulse pressure segregate a cluster of cardiovascular risk factors.

Office pulse pressure (PP) has been found to be independently associated with cardiovascular morbidity and mortality. While there is evidence that 24 h blood pressure (BP) is a better marker of the cardiovascular complications of hypertension than office BP, this information is still lacking in regard to PP. The aim of the present study was, therefore, to evaluate possible differences between office and 24 h PP in their relationship with cardiovascular risk profile. This cross-sectional study was performed in a group of 175 (104 M, 71 F) hypertensives (43 never treated before the study) free of clinical evidence of target organ disease. BP was measured at rest and during 24 h monitoring; cardiac structure and function was studied by ultrasounds; biochemical analyses were performed to evaluate some parameters of lipid and carbohydrate metabolism. Patients were divided into tertiles of office PP and of 24 h PP. Those in the highest tertile of PP had a significantly higher office and 24 h systolic BP along with a reduction in peripheral insulin sensitivity. Regarding cardiac structure and function, a significantly higher prevalence of concentric left ventricular hypertrophy (23 vs 55%; P=0.05) and an initial impairment of diastolic function with increase of the A wave was detected in hypertensives with higher PP. No difference between office and 24 h PP in detecting patients at higher cardiovascular risk was observed. In conclusion, office and 24 h pulse pressures were both able to segregate patients with a cluster of cardiovascular risk factors.

Serum cholesterol affects blood pressure regulation.

A close relationship between abnormalities of the lipid metabolism and arterial hypertension has been observed in several epidemiological studies. The aim of the present study was to investigate whether serum cholesterol might affect blood pressure (BP) levels at rest, during ambulatory monitoring or during sympathetic stimulation-independently of other variables such as body weight or serum insulin-thus influencing the outcome of hypertensive complications. Seventy-three patients with sustained newly-discovered and never-treated hypertension were divided into tertiles according to their serum cholesterol levels and their resting BP, 24-h BP and BP during isometric exercise (handgrip) were compared. Cardiac mass and carotid wall thickness were measured by echographic technique. The results were that tertiles were similar for body weight, blood glucose and serum insulin, but different for serum cholesterol and triglycerides. BP at rest and during 24-h monitoring was similar in the three groups, whilst a significant difference was detected during sympathetic stimulation by handgrip, with systolic and diastolic BP increasing by 16/12, 28/19 and 30/23 mm Hg (P < 0.01) in lower, medium and higher tertiles, respectively. Intima-media layer of the carotid arteries was also significantly thickened in the groups with higher cholesterol levels (0.54 +/- 0.07, 0.67 +/- 0.14, 0.68 +/- 0.15, P < 0.05). These data support the conclusion that even in patients with recently discovered hypertension, cholesterol levels may influence the BP response to adrenergic stimulation as well as the outcome of target organ disease.

Microelectromechanical systems and neurosurgery: a new era in a new millennium.

MICROMACHINES AND MICROELECTROMECHANICAL SYSTEMS (MEMS) are terms that are new to neurosurgeons but certain to become "household terms" in neurosurgery in the near future. These new terms serve as an introduction to a new world of sensors, actuators, and "smart systems" that will change the ways in which neurosurgeons interact with their environment. Through the use of microelectronics and micromachining technologies, MEMS will allow neurosurgeons to perform familiar tasks with greater precision, perform tasks that previously were not done at all, and monitor physiological and biochemical parameters more accurately and with greater safety. This review provides the information necessary to understand the fundamental concepts of MEMS and their application to the neurosurgical arena. It defines the relevant terms and describes the history behind the "micromachine revolution," the capabilities and limitations of MEMS technology, and how this revolution is germane to neurosurgery and to neurosurgeons.

Quantitative changes in spinal canal dimensions using interbody distraction for spondylolisthesis.

STUDY DESIGN: An experimental study was performed using cadaveric lumbar spines to evaluate the effect of anteriorly or laterally placed interbody distraction implants on the alteration of spinal canal and neuroforaminal dimensions. OBJECTIVES: To quantify changes in the spinal canal and neuroforaminal dimensions using interbody fusion devices inserted at various configurations in cadaveric lumbar spines exhibiting degenerative spondylolisthesis. SUMMARY OF BACKGROUND DATA: Although several clinical studies have demonstrated successful treatment of degenerative spondylolisthesis with anterior interbody fusion, no study has shown the role of interbody distraction in improving lumbar spinal canal and foraminal stenosis. METHODS: Five fresh cadaver lumbar spines exhibiting a degenerative spondylolisthesis or retrospondylolisthesis were used for the study. Computed tomography scans of each specimen and a silicon mold of the left intervertebral foramens were repeated in a consistent manner after pure compressive load (150 lb) was applied to simulate physiologic load (intact case), after two BAK (Sulzer SpineTech Inc., Minneapolis, MN) distraction plugs were anteriorly inserted into the intervertebral disc space (anterior distraction cases), and after one long BAK cage was laterally inserted from the left side (lateral distraction case). The cross-sectional area of the spinal canal was measured from computed tomography images using National Institutes of Health image software (Bethesda, MD). The spinal canal volume was calculated using the cross-sectional area and total scan thickness. Left intervertebral foraminal volumes were calculated from the weight of the silicon mold injected into the foramen. Descriptive statistics and a Student's t test were used to detect statistical differences in the spinal canal and neuroforaminal volumes before and after interbody distraction. RESULTS: The cross-sectional canal area was significantly increased after anterior distraction (35.11%) and lateral distraction (33.14%). The spinal canal volume was markedly increased with anterior distraction (19.92%) and lateral distraction (21.96%). Left foraminal volume was also enhanced by 40.25% for anterior distraction and 41.03% for lateral distraction. CONCLUSIONS: Interbody distraction either by anteriorly inserted plugs or laterally inserted threaded cagescan immediately improve the narrowed canal area and increase spinal canal, as well as foraminal volume for lumbar degenerative spondylolisthesis or retro- spondylolisthesis.

Effects of cervical spine posture on axial load bearing ability: a biomechanical study.

OBJECT: The authors conducted a study to assess the effects of cervical posture on the loadbearing ability of the cervical spine. METHODS: Twelve cervical spine specimens obtained in 12 adult sheep were tested. The specimens were randomly separated into two groups. In Group I the specimens were fixed in a lordotic posture, and in Group II they were fixed in a straight posture. Axial compressive loads were applied at a constant rate of 5 cm/minute. Load-to-failure, time-to-failure, piston displacement at failure, and failure modes were recorded. Statistical analyses were performed to detect differences between the groups. There was no significant difference in load-to-failure values between the two groups. However, the time-to-failure and the piston displacement values for the straight spines were significantly less than those for the lordotic spines. Additionally, the straight spines failed predominantly through ventral elements, whereas the lordotic spines predominantly failed dorsally. CONCLUSIONS: It is concluded that a loss of a lordosis increases the risk of injury to the cervical spine following axial loading.