A cohort study investigating a simple, early assessment to predict upper extremity function after stroke - a part of the SALGOT study

Background

For early prediction of upper extremity function, there is a need for short clinical measurements suitable for acute settings. Previous studies demonstrate correct prediction of function, but have ether included a complex assessment procedure or have an outcome that does not automatically correspond to motor function required to be useful in daily activity. The purpose of this study was to investigate whether a sub-set of items from the Action Research Arm Test (ARAT) at 3 days and 1 month post-stroke could predict the level of upper extremity motor function required for a drinking task at three later stages during the first year post-stroke.

Methods

The level of motor function required for a drinking task was identified with the Fugl-Meyer Assessment for Upper Extremity (FMA-UE). A structured process was used to select ARAT items not requiring special equipment and to find a cut-off level of the items’ sum score. The early prognostic values of the selected items, aimed to determine the level of motor function required for a drinking task at 10 days and 1 and 12 months, were investigated in a cohort of 112 patients. The patients had a first time stroke and impaired upper extremity function at day 3 after stroke onset, were ≥18 years and received care in a stroke unit.

Results

Two items, “Pour water from glass to glass” and “Place hand on top of head”, called ARAT-2, met the requirements to predict upper extremity motor function. ARAT-2 is a sum score (0-6) with a cut-off at 2 points, where >2 is considered an improvement. At the different time points, the sensitivity varied between 98 % and 100 %, specificity between 73 % and 94 %. Correctly classified patients varied between 81 % and 96 %.

Conclusions

Using ARAT-2, 3 days post-stroke could predict the level of motor function (assessed with FMA-UE) required for a drinking task during the first year after a stroke. ARAT-2 demonstrates high predictive values, is easily performed and has the potential to be clinically feasible.

Trail registration

ClinicalTrials.gov: NCT01115348

An overview of systematic reviews on upper extremity outcome measures after stroke

BACKGROUND

Although use of standardized and scientifically sound outcome measures is highly encouraged in clinical practice and research, there is still no clear recommendation on which tools should be preferred for upper extremity assessment after stroke. As the aims, objectives and methodology of the existing reviews of the upper extremity outcome measures can vary, there is a need to bring together the evidence from existing multiple reviews. The purpose of this review was to provide an overview of evidence of the psychometric properties and clinical utility of upper extremity outcome measures for use in stroke, by systematically evaluating and summarizing findings from systematic reviews.

METHODS

A comprehensive systematic search was performed including systematic reviews from 2004 to February 2014. A methodological quality appraisal of the reviews was performed using the AMSTAR-tool.

RESULTS

From 13 included systematic reviews, 53 measures were identified of which 13 met the standardized criteria set for the psychometric properties. The strongest level of measurement quality and clinical utility was demonstrated for Fugl-Meyer Assessment, Action Research Arm Test, Box and Block Test, Chedoke Arm and Hand Activity Inventory, Wolf Motor Function Test and ABILHAND.

CONCLUSIONS

This overview of systematic reviews provides a comprehensive systematic synthesis of evidence on which outcome measures demonstrate a high level of measurement quality and clinical utility and which can be considered as most suitable for upper extremity assessment after stroke. This overview can provide a valuable resource to assist clinicians, researchers and policy makers in selection of appropriate outcome measures.

Intra-rater and inter-rater reliability at the item level of the Action Research Arm Test for patients with stroke

OBJECTIVE

To examine the intra- and inter-rater reliability of the Action Research Arm Test (ARAT) at the item level after stroke.

DESIGN

An intra-rater and inter-rater reliability study.

SUBJECTS

Thirty-five participants (median age 62 years, median time post-stroke 22 months) with impaired upper extremity function after stroke were included in the study.

METHODS

Two physiotherapists simultaneously, but independently, assessed the participants' performance in all 19 items of the ARAT twice in 1 day. A rank-based statistical method for paired ordinal data, including calculation of percentage agreement (PA), systematic disagreements (relative position (RP), relative concentration (RC)) and individual variability (relative rank variance (RV)) was used.

RESULTS

Satisfactory intra-rater and inter-rater agreement was noted for all items except item 19, which was just below satisfactory level. Within and between raters, small but non-negligible systematic disagreements were found for items 11, 14 and 19 and for items 1, 4, 17 and 19, respectively. There was no disagreement due to random variance within or between raters.

CONCLUSION

The ARAT is a highly reliable observational rating scale at the item level after stroke. Awareness regarding the small systematic disagreements demonstrated in some items is, however, recommended when using ARAT.

Responsiveness of Upper Extremity Kinematic Measures and Clinical Improvement During the First Three Months After Stroke

Background. Kinematic movement analysis is increasingly used as an outcome measure in evaluation of upper extremity function after stroke. Little is known, however, about what observed longitudinal changes in kinematics mean in the context of an individual’s functioning. In this study, the responsiveness and expected change in kinematic measures associated with clinically meaningful improvement in the upper extremity were evaluated. Methods. Kinematic movement analysis of a drinking task and Action Research Arm Test (ARAT) were performed early (9 days poststroke) and at 3 months after stroke in 51 subjects. The receiver-operating characteristic curve and linear regression analyses were used to evaluate responsiveness of kinematic parameters. Results. Movement time, smoothness, and trunk displacement discriminated those subjects demonstrating clinically meaningful improvements. Significant associations of 31% to 36% were found between the change in ARAT and kinematic measures. A real clinical improvement in kinematics lies in the range of 2.5 to 5 seconds, 3 to 7 units, and 2 to 5 cm in movement time, smoothness, and trunk displacement, respectively. Conclusions. All kinematic measures reported in this study are responsive measures for capturing improvements in the upper extremity during the first 3 months after stroke. Approximate estimates for the expected change in kinematics associated with clinically meaningful improvement in upper extremity activity capacity illustrate the usefulness of the linear regression analysis for assessing responsiveness. This knowledge facilitates the selection of kinematic measures for clinical and movement analysis research as well as for technology-based devices.

Movement Kinematics During a Drinking Task Are Associated With the Activity Capacity Level After Stroke

Background. Kinematic analysis is a powerful method for an objective assessment of movements and is increasingly used as an outcome measure after stroke. Little is known about how the actual movement performance measured with kinematics is related to the common traditional assessment scales. The aim of this study was to determine the relationships between movement kinematics from a drinking task and the impairment or activity limitation level after stroke. Methods. Kinematic analysis of movement performance in a drinking task was used to measure movement time, smoothness, and angular velocity of elbow and trunk displacement (TD) in 30 individuals with stroke. Sensorimotor impairment was assessed with the Fugl-Meyer Assessment (FMA), activity capacity limitation with the Action Research Arm Test (ARAT), and self-perceived activity difficulties with the ABILHAND questionnaire. Results. Backward multiple regression revealed that the movement smoothness (similarly to movement time) and TD together explain 67% of the total variance in ARAT. Both variables uniquely contributed 37% and 11%, respectively. The TD alone explained 20% of the variance in the FMA, and movement smoothness explained 6% of the variance in the ABILHAND. Conclusions. The kinematic movement performance measures obtained during a drinking task are more strongly associated with activity capacity than with impairment. The movement smoothness and time, possibly together with compensatory movement of the trunk, are valid measures of activity capacity and can be considered as key variables in the evaluation of upper-extremity function after stroke. This increased knowledge is of great value for better interpretation and application of kinematic data in clinical studies.

SALGOT--Stroke Arm Longitudinal study at the University of Gothenburg, prospective cohort study protocol

Background

Recovery patterns of upper extremity motor function have been described in several longitudinal studies, but most of these studies have had selected samples, short follow up times or insufficient outcomes on motor function. The general understanding is that improvements in upper extremity occur mainly during the first month after the stroke incident and little if any, significant recovery can be gained after 3-6 months. The purpose of this study is to describe the recovery of upper extremity function longitudinally in a non-selected sample initially admitted to a stroke unit with first ever stroke, living in Gothenburg urban area.

Methods/Design

A sample of 120 participants with a first-ever stroke and impaired upper extremity function will be consecutively included from an acute stroke unit and followed longitudinally for one year. Assessments are performed at eight occasions: at day 3 and 10, week 3, 4 and 6, month 3, 6 and 12 after onset of stroke. The primary clinical outcome measures are Action Research Arm Test and Fugl-Meyer Assessment for Upper Extremity. As additional measures, two new computer based objective methods with kinematic analysis of arm movements are used. The ABILHAND questionnaire of manual ability, Stroke Impact Scale, grip strength, spasticity, pain, passive range of motion and cognitive function will be assessed as well. At one year follow up, two patient reported outcomes, Impact on Participation and Autonomy and EuroQol Quality of Life Scale, will be added to cover the status of participation and aspects of health related quality of life.

Discussion

This study comprises a non-selected population with first ever stroke and impaired arm function. Measurements are performed both using traditional clinical assessments as well as computer based measurement systems providing objective kinematic data. The ICF classification of functioning, disability and health is used as framework for the selection of assessment measures. The study design with several repeated measurements on motor function will give us more confident information about the recovery patterns after stroke. This knowledge is essential both for optimizing rehabilitation planning as well as providing important information to the patient about the recovery perspectives.

Trial registration

ClinicalTrials.gov: NCT01115348

Kinematic variables quantifying upper-extremity performance after stroke during reaching and drinking from a glass

BACKGROUND

Three-dimensional kinematic analysis provides quantitative and qualitative assessment of upper-limb motion and is used as an outcome measure to evaluate impaired movement after stroke. The number of kinematic variables used, however, is diverse, and models for upper-extremity motion analysis vary.

OBJECTIVE

The authors aim to identify a set of clinically useful and sensitive kinematic variables to quantify upper-extremity motor control during a purposeful daily activity, that is, drinking from a glass.

METHODS

For this purpose, 19 participants with chronic stroke and 19 healthy controls reached for a glass of water, took a sip, and placed it back on a table in a standardized way. An optoelectronic system captured 3-dimensional kinematics. Kinematical parameters describing movement time, velocity, strategy and smoothness, interjoint coordination, and compensatory movements were analyzed between groups.

RESULTS

The majority of kinematic variables showed significant differences between study groups. The number of movement units, total movement time, and peak angular velocity of elbow discriminated best between healthy participants and those with stroke as well as between those with moderate (Fugl-Meyer scores of 39-57) versus mild (Fugl-Meyer scores of 58-64) arm impairment. In addition, the measures of compensatory trunk and arm movements discriminated between those with moderate and mild stroke impairment.

CONCLUSION

Kinematic analysis in this study identified a set of movement variables during a functional task that may serve as an objective assessment of upper-extremity motor performance in persons who can complete a task, such as reaching and drinking, after stroke.

Parecoxib for analgesia after craniotomy

BACKGROUND

Pain after craniotomy is often under-treated. Opiates carry distinct disadvantages. Non-steroidal anti-inflammatory drugs have an anti-platelet action and carry a bleeding risk. Cyclo-oxygenase 2 inhibitors such as parecoxib are not associated with a bleeding risk and would be welcome analgesics if shown to be effective.

METHODS

In a prospective double-blind, randomized, placebo-controlled study, we investigated the analgesic effect of a single dose of parecoxib 40 mg given at dural closure in 82 patients undergoing elective craniotomies. Remifentanil was used intraoperatively, and i.v. morphine was titrated to the requirement in the post-anaesthetic unit. On the ward, i.m. morphine 5 mg as required and regular acetaminophen was prescribed. Morphine use and visual analogue pain scores were recorded at 1, 6, 12, and 24 h after surgery.

RESULTS

Parecoxib reduced pain scores at 6 h and morphine use at 6 and 12 h after operation. However, overall, it had only minimal impact on postoperative analgesia. We found a wide variability in analgesic requirements where 11% of patients required no opioids and 16% required more than 15 mg i.v. morphine 1 h after the surgery.

CONCLUSIONS

We found only limited evidence to support parecoxib as an analgesic after craniotomy.

Is arteriovenous shunting involved in the development of varicosities? A study of the intraluminal pressure and oxygen content in varicose veins

OBJECTIVES

Arteriovenous (AV) shunting has been postulated as the underlying cause of varicose veins. The aim of this study was to analyse pressure and oxygen content in primary varicose veins in order to determine evidence of arterial shunting.

METHODS

Thirty-nine patients with varicose veins underwent cannulation of varicosities. The pressure and the blood oxygen content within varicosities were measured in different positions and during exercise. Similar measurements were made in the long saphenous veins of 10 control subjects without venous disease.

RESULTS

Mean pressure in varicose veins in the supine position was 12.3 mmHg (Standard deviation [SD] 3.6 mmHg). Control subjects had similar pressures measured in the long saphenous vein. No pulsatile pressure tracings were obtained. Varicosity pressures in the erect position averaged 66 mmHg (SD 9 mmHg). In all cases, the pressure correlated with the distance of the varicosity from the heart. Pressure reduction in varicosities after exercise was significantly less than that in control subjects. Recovery time (RT 90) was also significantly shorter than in the control group. Mean venous pO2 in varicosities was 4.5 kPa (SD 1.0) in the supine position dropping to 3.9 kPa (SD 0.9) on standing; these values were not significantly different to samples from control subjects.

CONCLUSIONS

AV shunting is unlikely to be a causative factor in the development of primary varicose veins.

Tube structures of probable microbial origin in the Neoarchean Carawine Dolomite, Hamersley Basin, Western Australia

The approximately 2.63 Ga Carawine Dolomite, Hamersley Basin, Western Australia, preserves tube structures of probable microbial origin that formed in a low energy environment. The tubes are 0.4-1.8 cm in diameter and at least 10-16 cm long in outcrop. The tubes are defined by dark, 45-microm-thick dolomicritic walls, whereas the tube fill and host rock are composed of 30 microm, cloudy dolomite crystals and rare 170- to 425-microm-wide, dark well-sorted clasts. Closely spaced, rarely discontinuous laminae coat the insides of tubes; less closely spaced, peaked, discontinuous laminae coat the outsides of tubes. The laminae on the outsides of tubes are often intercalated with mammilate structures. The presence of probable microbial coatings on both the insides and the outsides of the tube walls requires that the tubes formed above the sediment-water interface. These tube structures probably formed during gas-charged fluid escape, similar to tubes observed in ancient and modern hydrocarbon seeps and cylindrical water transfer structures in sandstones. The laminae that coat the tubes have very similar geometries to modern biofilms that form in both turbulent and laminar flow, and their geometries probably reflect flow conditions during the fluid escape. The identification of these structures suggests that the preserved interaction between fluid escape and microbial growth in carbonates may be more common than previously thought.

Fast Track Open Aortic Surgery: Reduced Post Operative Stay with a Goal Directed Pathway

OBJECTIVE

Open aortic aneurysm repair is traditionally associated with an extended hospital stay. The aim of this study was to examine the feasibility of reducing post-operative stay through the implementation of a fast-track, goal directed, clinical pathway for elective open aortic surgery.

METHODS

A fast-track clinical pathway for aortic surgery was introduced in a regional vascular unit in September 2005. The pathway has daily goals and targets discharge for all patients on the 3rd post operative day. This study compares thirty consecutive discharges of unselected patients undergoing elective infra-renal aortic surgery following introduction of the pathway to the thirty consecutive cases preceding its introduction. Reasons for prolonged hospital stay were recorded.

RESULTS

Six of thirty patients achieved discharge by Day 3. The median hospital stay reduced from 9 (range 4 to 17 days) to 5 days (range 2 to 12 days) following introduction of the pathway. There was one readmission within 30 days and no complications attributable to the pathway implementation. Cardiac complications and home planning were the most common causes of delayed discharge.

CONCLUSION

Post-operative stay in patients undergoing standard elective open infra-renal aortic surgery can be safely reduced with the introduction of a goal directed pathway.

Nasal hyperreactivity in allergic and non-allergic rhinitis: a potential risk factor for non-specific building-related illness

Self-reported non-allergic nasal symptom triggers in non-allergic ('vasomotor') rhinitis overlap with commonly identified environmental exposures in non-specific building-related illness. These include extremes of temperature and humidity, cleaning products, fragrances, and tobacco smoke. Some individuals with allergic rhinitis also report non-allergic triggers. We wished to explore the phenotypic overlap between allergic and non-allergic rhinitis by ascertaining self-reported non-allergic nasal symptom triggers among allergic rhinitics. Sixty subjects without work-related respiratory exposures or symptoms, aged 19-68 years, stratified by age, gender and (skin test-proven) allergic rhinitis status, were queried with regard to self-reported non-allergic nasal symptom triggers (aggregate score 0-8). In this sample, the number of self-reported non-allergic triggers was bimodal, with peaks at 1 and 5. Forty-two percent of seasonal allergic rhinitic subjects reported more than three non-allergic triggers, compared with only 3% of non-allergic non-rhinitics (P < 0.01). Subjects over 35 years were more likely to report one or more non-allergic triggers, particularly tobacco smoke (P < 0.05). Allergic rhinitics reported more non-allergic symptom triggers than did non-allergic, non-rhinitics. As indexed by self-reported reactivity to non-specific physical and chemical triggers, both non-allergic rhinitics and a subset of allergic rhinitics may constitute susceptible populations for non-specific building-related illness.

PRACTICAL IMPLICATIONS

Judging by self-report, a substantial subset of individuals with allergic rhinitis--along with all individuals with nonallergic rhinitis (by definition)--are hyperreactive to non-allergic triggers. There is overlap between these triggers (elicited in the process of obtaining a clinical diagnosis) and environmental characteristics associated with ''problem buildings.'' Since individuals with self-identified rhinitis report an excess of symptoms in most epidemiologic studies of problem buildings (even in the absence of unusual aeroallergen levels), rhintics may be acting as a ''sentinel'' subgroup when indoor air quality is suboptimal. Together, non-allergic rhinitics plus allergic rhinitics with prominent non-allergic triggers, are thought to constitute approximately one-sixth of the US population.

Putting the ‘landscape’ in landscape genetics

Landscape genetics has emerged as a new research area that integrates population genetics, landscape ecology and spatial statistics. Researchers in this field can combine the high resolution of genetic markers with spatial data and a variety of statistical methods to evaluate the role that landscape variables play in shaping genetic diversity and population structure. While interest in this research area is growing rapidly, our ability to fully utilize landscape data, test explicit hypotheses and truly integrate these diverse disciplines has lagged behind. Part of the current challenge in the development of the field of landscape genetics is bridging the communication and knowledge gap between these highly specific and technical disciplines. The goal of this review is to help bridge this gap by exposing geneticists to terminology, sampling methods and analysis techniques widely used in landscape ecology and spatial statistics but rarely addressed in the genetics literature. We offer a definition for the term "landscape genetics", provide an overview of the landscape genetics literature, give guidelines for appropriate sampling design and useful analysis techniques, and discuss future directions in the field. We hope, this review will stimulate increased dialog and enhance interdisciplinary collaborations advancing this exciting new field.

Three-dimensional kinematic motion analysis of a daily activity drinking from a glass: a pilot study

Background

Development of reliable and objective evaluation methods is required, particularly for natural and goal-oriented upper-extremity tasks. Three-dimensional imaging measurement techniques have turned out to be a powerful tool for a quantitative and qualitative assessment of multijoint movements. The purpose of this study was to develop and test a method of three-dimensional motion analysis for the activity "drinking from a glass" and describe the drinking task with kinematic variables in control subjects.

Methods

A protocol was developed for the drinking activity including the set-up of cameras and positions of the markers and the subject. The drinking task included reaching, forward transport with glass, drinking, back transport and returning the hand to the initial position. An optoelectronic system was used for the three-dimensional kinematic motion capture. Movement times, velocities, joint angles and interjoint coordination for shoulder and elbow were computed and analyzed for twenty control subjects. Test-retest consistency was evaluated for six subjects.

Results

The test protocol showed good consistency in test-retest. Phase definitions for the drinking task were defined and verified. Descriptive kinematic variables were obtained for movement times, positions, velocities and joint angles for shoulder and elbow joint. Interjoint coordination between shoulder and elbow joint in reaching phase showed a high correlation.

Conclusion

This study provides a detailed description of the three-dimensional kinematic analysis of the drinking task. Our approach to investigate and analyze a goal-oriented daily activity has a great clinical potential. Consequently, the next step is to use and test this protocol on persons with impairments and disabilities from upper extremities.

Seizures, not hippocampal neuronal death, provoke neurogenesis in a mouse rapid electrical amygdala kindling model of seizures

PURPOSE

Proliferation of neural precursors adjacent to the granule cell layer of the dentate gyrus has been identified in previous epilepsy models. Convincingly demonstrating that seizure activity is the stimulant for neurogenesis, rather than neuronal death or other insults inherent to seizure models, is difficult. To address this we derived a rapid electrical amygdala kindling model in mice known to be resistant to seizure-induced neuronal death as an experimental model of focal seizures and to analyze subsequent neurogenesis.

METHODS

Mice were implanted with bipolar electrodes in the left amygdala and given electrical stimulation (3 s, 100 Hz, 1 ms monophasic square wave pulses every 5 min, 40 in total) while being observed and graded for the development of seizures. Neurogenesis in the hippocampus was assessed by counting bromodeoxyuridine-immunoreactive cells co-labeled for astrocyte (glial fibrillary acidic protein) and neuronal nuclear markers.

RESULTS

Bromodeoxyuridine-reactive cell numbers were three-fold higher in stimulated mice compared with controls at 1 week in the subgranular region and at three weeks extensive co-labeling with neuronal nuclear was noted in cells which had migrated into the body of the granule cell layer, while mice receiving stimulation but failing to kindle did not differ significantly from controls. No increase in neuronal death was detected by terminal deoxynucleotidyl transferase-mediated digoxigenin-11-dUTP nick end labeling, Fluorojade or fluorescent examination of hematoxylin and eosin-stained sections in any inter-group comparison.

CONCLUSIONS

We propose that this kindling paradigm, not previously applied to mice, demonstrates more convincingly than previously the surge in neurogenesis in response to seizures, and the effects of seizures alone in regard to neuronal injury and regeneration.

Cavernous haemangioma presenting with obstructive hydrocephalus

With the development of MRI, the natural history of cavernous haemangiomas has been appreciated. This article describes a series of patients with deep cavernous haemangiomas who have presented with acute hydrocephalus. The diagnosis and treatment options are discussed with a review of the literature.

Plasma levobupivacaine concentrations following scalp block in patients undergoing awake craniotomy

BACKGROUND

Levobupivacaine is an effective local anaesthetic agent for nerve blockade with less systemic toxicity than racemic bupivacaine. The safety and efficacy of levobupivacaine for scalp blockade during awake craniotomy have not been addressed previously.

METHODS

Serial arterial plasma levobupivacaine concentrations following scalp blockade were measured to 2 h in 10 patients booked for awake craniotomy for epilepsy or tumour surgery. Bilateral scalp blockade providing surgical anaesthesia was achieved with a mean dose of 177 mg (2.5 mg kg(-1), range 1.6-3.2 mg kg(-1)) of levobupivacaine (0.5%, 5 mg ml(-1)) with epinephrine (5 microg ml(-1)) added immediately before the block insertion.

RESULTS

The maximum measured plasma levobupivacaine concentration was 1.58 (0.44) microg ml(-1) [mean (SD)] with a mean time to peak plasma concentration of 12 (4) min. There were no episodes in any of the 10 patients of symptoms or signs suggestive of either CNS or CVS toxicity.

CONCLUSIONS

This study demonstrated a relatively rapid rise of plasma levobupivacaine concentration without evidence of cardiovascular or central nervous system sequelae in a sample population of patients who may be particularly prone to perioperative seizures.

MRI-negative PET-positive temporal lobe epilepsy: a distinct surgically remediable syndrome

Most patients with non-lesional temporal lobe epilepsy (NLTLE) will have the findings of hippocampal sclerosis (HS) on a high resolution MRI. However, a significant minority of patients with NLTLE and electroclinically well-lateralized temporal lobe seizures have no evidence of HS on MRI. Many of these patients have concordant hypometabolism on fluorodeoxyglucose-PET ([18F]FDG-PET). The pathophysiological basis of this latter group remains uncertain. We aimed to determine whether NLTLE without HS on MRI represents a variant of or a different clinicopathological syndrome from that of NLTLE with HS on MRI. The clinical, EEG, [18F]FDG-PET, histopathological and surgical outcomes of 30 consecutive NLTLE patients with well-lateralized EEG but without HS on MRI (HS-ve TLE) were compared with 30 consecutive age- and sex-matched NLTLE patients with well-lateralized EEG with HS on MRI (HS+ve TLE). Both the HS+ve TLE group and the HS-ve TLE patients had a high degree of [18F]FDG-PET concordant lateralization (26 out of 30 HS-ve TLE versus 27 out of 27 HS+ve TLE). HS-ve TLE patients had more widespread hypometabolism on [18F]FDG-PET by blinded visual analysis [odds ratio (OR = + infinity (2.51, -), P = 0.001]. The HS-ve TLE group less frequently had a history of febrile convulsions [OR = 0.077 (0.002-0.512), P = 0.002], more commonly had a delta rhythm at ictal onset [OR = 3.67 (0.97-20.47), P = 0.057], and less frequently had histopathological evidence of HS [OR = 0 (0-0.85), P = 0.031]. There was no significant difference in surgical outcome despite half of those without HS having a hippocampal-sparing procedure. Based on the findings outlined, HS-ve PET-positive TLE may be a surgically remediable syndrome distinct from HS+ve TLE, with a pathophysiological basis that primarily involves lateral temporal neocortical rather than mesial temporal structures.

Trauma as a precipitant of haemorrhage in synovial cysts

Synovial cysts have been well reported as a cause of sciatica, with a sudden acute exacerbation being attributed to haemorrhage and subsequent enlargement of the cyst. Cyst formation is attributed to facet joint degeneration associated with a defect or rupture of the joint capsule. The mechanisms of haemorrhage have not been well described previously. Two cases of haemorrhagic synovial cysts causing acute exacerbation of sciatica are described. Both cases were directly attributable to manipulation of degenerate spines. The MRI and histopathological findings are discussed and we propose a mechanism whereby excessive stress on a degenerate revascularized synovium leads to haemorrhage within synovial cysts.

Chlorine inhalation produces nasal congestion in allergic rhinitics without mast cell degranulation

Seasonal allergic rhinitic (SAR) subjects are more sensitive to nasal irritants than nonrhinitic (NR) subjects; however, the mechanism underlying this difference is unclear. This study sought to determine whether irritant-induced nasal congestion involves mast cell degranulation. Eight SAR and eight NR subjects were exposed to both 1.0 parts per million chlorine and filtered air in separate visits; exposures were via nasal mask and lasted 15 min. Rhinomanometry was performed before, immediately after and 15 min after exposure. Following > or = 2 weeks, exposures and symptom reporting were repeated with nasal lavage, rather than rhinomanometry, pre- and postexposure. A separate substudy using rye grass antigen provided a positive control. Mast cell tryptase was measured in nasal lavage fluid from both substudies using an automated fluoroenzyme immunoassay. Chlorine provocation significantly increased nasal airway resistance in SAR but not NR subjects. Conversely, tryptase levels in nasal lavage fluid were unaffected. Nasal allergen challenge significantly increased both nasal obstruction and nasal lavage tryptase in SAR subjects. Irritant-induced nasal congestion is more pronounced among seasonal allergic rhinitic than nonrhinitic subjects. However, unlike nasal allergen challenge, the mechanism of response to chlorine does not appear to involve mast cell degranulation.

Treatment of Staphylococcus epidermidis ventriculo-peritoneal shunt infection with linezolid

Gram-positive bacterial meningitis frequently complicates ventriculo-peritoneal (VP) shunts used for hydrocephalus. Linezolid, an oxazolidinone, is active against Gram-positive cocci, and has excellent CSF penetration. We present a 22-year-old woman who was cured of a Staphylococcus epidermidis VP shunt infection via shunt removal and intravenous linezolid.

Insertion of depth electrodes with or without subdural grids using frameless stereotactic guidance systems--technique and outcome

Over recent years frameless stereotactic systems have begun replacing framed systems for many neurosurgical procedures. However, little has been published regarding the use of these systems to guide intracranial electrode implantation for epilepsy surgery patients. Here we report our experience utilising such a system to insert depth electrodes and subdural grid electrodes. The SteathStation Image-Guided System (SSIGS) (Sofamor Danek, Memphis TN.) was used to insert bilateral depth electrodes in 13 patients, of whom 5 also underwent the insertion of subdural grids or strip electrodes. Initially, a surgical plan based on an entry and target point on axial and sagittal images was performed for the insertion of electrodes. Navigational views, using three-planar images, were then performed to determine which structures the electrodes would pass through to be correctly placed in the amygdala and hippocampus. The correct site of electrode implantation was confirmed post-operatively by spiral CT scans in 4 patients (which were then co-registered to the pre-implantation MRI using a surface matching technique) and the other 9 patients by post-implantation MRI. The SSIGS was found to have a mean registration error of 2.0 mm (range 1.8-2.5) in 10 cases; in the 3 cases where the error was greater than 2.5 mm a surfacemerge technique was used with a mean error 0.9 (0.8-1.00). The post-implantation MRI or CT-MRI co-registration confirmed an accurate electrode placement in the mesial temporal region in all cases. Seizure onset lateralisation was achieved in 11 patients, all of whom went onto formal resections based on these results. The only long-term complication was a case of osteomyelitis which required removal of the bone flap. 73% of patients had an excellent seizure outcome. Frameless stereotactic systems can be safely used to intracranial electrodes, avoid the disadvantages of the framed system and have the added advantage of the surgeon being able to visualise the trajectory and to adjust this to avoid vital structures. As well they eliminate surgical obstruction to the insertion of subdural grids at the same operation, which may be caused by a framed system.

A reduction in serum cytokine levels parallels healing of venous ulcers in patients undergoing compression therapy

INTRODUCTION

vascular endothelial growth factor (VEGF) and tumour necrosis factor alpha (TNF(alpha)) have been specifically implicated in the tissue damage associated with chronic venous disease (CVD). Furthermore, production of both factors is known to be upregulated in vessel wall cells subject to hypertension. The aim of this study was to determine the local venous levels of VEGF and TNF(alpha) in limbs with venous ulcers before and after treatment with graduated compression.

PATIENTS AND METHODS

eight patients with venous ulcers and 8 patients with varicose veins only were included in the study. For ulcer patients, serum samples were taken from the superficial veins in lower limbs and repeated after 4 weeks of treatment with 4-layered graduated compression. Serum from the arms of the same patients served as controls. Determination of the concentrations of VEGF and TNF(alpha) proteins were performed with sandwich enzyme-linked immunosorbent assays.

RESULTS

both groups of patients had elevated levels of VEGF and TNF(alpha). In patients with venous ulcers there was a reduction in the levels of both cytokines to below control values with treatment. These changes correlated with healing of the ulcers as determined by reduction in ulcer size.

CONCLUSION

these data, for the first time, suggest a central role for both TNF(alpha) and VEGF in the pathogenesis of venous ulceration which may constitute a causative link between venous hypertension and tissue pathology.

Psychometric characteristics of the Parenting Scale in a head start population

Examined the reliability, construct, and concurrent validity of the Parenting Scale (PS), a brief instrument designed to measure dysfunctional parenting practices for parents of young children. In Study 1, 183 primarily African American mothers and their Head Start children completed the PS. The PS, which consists of 3 subscales--Laxness, Overreactivity, and Verbosity--was subjected to confirmatory factor analysis (CFA). Neither the original 3-factor structure, nor a 2-factor structure consisting of the original Laxness and Overreactivity factors, fit the data. A subsequent exploratory factor analysis yielded a 2-factor solution that was generally consistent with the Overreactivity and Laxness subscales identified by Arnold, O'Leary, Wolff, and Acker (1993). The 2-factor CFA solution was replicated with a sample of 216 similar mothers, and the 5-item Overreactivity and Laxness subscales retained internal consistencies above .70. Analysis of the convergent validity of the modified PS and its 2 subscales revealed moderate associations with measures of permissiveness, authoritarianism, involvement, and limit setting. Scores on the PS were not correlated significantly with measures of social desirability, maternal education level, or parent report of internalizing behavior problems. Concurrent validity evidence was obtained by correlating the PS with measures of parenting satisfaction and support, parenting stress, maternal depression, and measures of externalizing child behavior problems.

Regulation of STAT protein synthesis by c-Cbl

Many cytokines and growth factors induce transcription of immediate early response genes by activating members of the Signal Transducers and Activators of Transcription (STAT) family. Although significant progress has been made in understanding the events that lead to the activation of STAT proteins, less is known about the regulation of their expression. Here we report that murine embryonic fibroblasts derived from c-Cbl-deficient mice display significantly increased levels of STAT1 and STAT5 protein. In contrast, STAT2 and STAT3 expression, as well as the levels of the tyrosine kinases Jak1 and Tyk2, appear to be regulated independently of c-Cbl. Interestingly, the half-life of STAT1 was unaffected by the presence of c-Cbl, indicating that c-Cbl acts independently of STAT1 degradation. Further analysis revealed similar levels of STAT1 mRNA, however, a dramatically increased rate of STAT1 protein synthesis was observed in c-Cbl-deficient cells. Thus, our findings demonstrate an additional control mechanism over STAT1 function, and also provide a novel biological effect of the Cbl protein family.

Information for surgical patients: implications of the World Wide Web

OBJECTIVE

To sample the amount and scope of information available on the internet about three common surgical conditions, identify the sources, and to examine the relevance of the web to the surgical community.

DESIGN

Internet search.

SETTING

General hospital, Republic of Ireland.

MATERIAL

Three arbitrarily chosen conditions were sought--varicose veins, inguinal hernia, and gallstones. Four commonly used search engines--Yahoo, Altavista, Excite and Lycos, were used to search worldwide, and then sites restricted to the UK and Republic of Ireland.

MAIN OUTCOME MEASURES

Quality and quantity of information available.

RESULTS

All four search engines retrieved patient-orientated information on the three conditions. The sites accessed from the web page matches generally presented a comprehensive summary of the condition including aetiology, risk factors and clinical features, but gave variable amounts of information on treatment options, surgical complications, comparisons between treatments, and expected outcomes. Online health magazines provided most of the information sites.

CONCLUSION

The internet offers easily-accessible patient-orientated information. Surgeons should make more use of it to satisfy patients' increasing need for information.

Amino acid deletion at codon 67 and Thr-to-Gly change at codon 69 of human immunodeficiency virus type 1 reverse transcriptase confer novel drug resistance profiles

The potential roles of an amino acid deletion at codon 67 (Delta67) and a Thr-to-Gly change at codon 69 (T69G) in the reverse transcriptase of human immunodeficiency virus (HIV) type 1 in drug sensitivity and relative replication fitness were studied. Our results suggest that the Delta67 and T69G changes can be categorized as mutations associated with multidrug resistance. The combination of both mutations with an L74I change (Delta67+T69G/L74I) leads to a novel 3'-azido-3'-deoxythymidine resistance motif and compensates for impaired HIV replication.

Optimizing intrapulmonary perfluorocarbon distribution: Fluoroscopic comparison of mode of ventilation and body position

OBJECTIVE

Partial liquid ventilation with the perfluorochemical, perflubron, has been shown to improve lung mechanics and enhance gas exchange in the treatment of severe acute lung injury. However, the most effective strategy to provide optimal intrapulmonary distribution of perflubron has not been fully accessed. The objective of this study was to examine the effect of body position (supine vs. rotational) and mode of ventilation (conventional mechanical ventilation [CMV] vs. high-frequency oscillatory ventilation [HFOV]) on perflubron distribution and oxygenation improvement.

DESIGN

Prospective, randomized, animal trial.

SETTING

Research laboratory at a university medical center.

SUBJECTS

Twenty healthy piglets (4.5-6.6 kg).

INTERVENTIONS

Subjects underwent repetitive saline lavage to achieve a uniform degree of lung injury and then were randomized to either CMV or were converted to HFOV. Within each ventilator group, animals were randomized to supine positioning (S) or rotational positioning with alternation between supine and prone position (R) during incremental dosing of three 5-mL/kg doses of perflubron.

MEASUREMENTS AND MAIN RESULTS

Arterial blood gas tensions, hemodynamic variables, and the oxygenation index were recorded after each dose of 5 mL/kg. Lateral cinefluoroscopic images after each dose were digitized for computer analysis of density. A density index was calculated for a 2-cm2 window in three dorsal and three ventral lung regions. Uniformity of distribution was calculated by comparing the mean density among the six regions. Oxygenation improvements were compared between groups. There were no significant differences in hemodynamic variables or gas exchange after lung injury in the four groups. Rotational positioning produced significantly more uniform perflubron distribution during both CMV and HFOV. This effect was independent of the mode of ventilation. The mean ventral density index was affected by rotating position and HFOV mode of ventilation after 10 mL/kg of perflubron, and rotating position was affected only after 15 mL/kg of perflubron. There was a significant reduction in the oxygenation index from baseline to end lavage in both CMV groups, as well as all of the animals that were rotated.

CONCLUSION

Perflubron is more uniformly dispersed when dosed in a rotational fashion with alternation between supine and prone position during incremental dosing. This effect is independent of mode of ventilation. There was no relationship between oxygenation improvements and nondependent perflubron distribution. CMV and rotating dosing both led to a significant decrease in the oxygenation index after a 15 mL/kg dose of perflubron. This information has important impact on the future development of dosing strategies and clinical trial design.

The influence of sex, allergic rhinitis, and test system on nasal sensitivity to airborne irritants: a pilot study

"Nasal irritant sensitivity" is an important construct in environmental health science; functional measures, however, lack standardization. We performed duplicate measures of nasal irritant perceptual acuity on 16 subjects (evenly divided by sex and seasonal allergy status) using two different test compounds: carbon dioxide (CO2) (detection) and n-propanol (localization). The a priori hypotheses included a) allergic rhinitics will display lower perceptual thresholds than nonrhinitics; b) females will display lower perceptual thresholds than males; and c) estimates of perceptual acuity using the two test systems will be positively correlated. We obtained CO2 detection thresholds using an ascending concentration series, presenting 3-sec pulses of CO2, paired with air in random order, by nasal cannula. We obtained localization thresholds by simultaneously presenting stimuli (ascending concentrations of n-propanol vapor in air) and blanks (saturated water vapor in air) to opposite nostrils, with laterality randomized. In terms of test-retest reliability, individual replicate measures for CO2 detection thresholds correlated more closely than did the localization thresholds of volatile organic compounds (VOC) (r = 0.65 and r = 0.60, respectively). As an intertest comparison, log-transformed individual mean CO2 and VOC measures were positively correlated with an r of 0.63 (p < 0.01). In univariate analyses, sex predicted both log-transformed CO2 and VOC thresholds (females being more "sensitive"; p < 0.05 and 0.001, respectively). Nasal allergies predicted sensory testing results only in the multivariate analysis, and then only for VOC localization (p < 0.05). The question of population variation in nasal irritant sensitivity (as well as the generalizability of results across test compounds) deserves further attention.

The Cbl protooncoprotein stimulates CSF-1 receptor multiubiquitination and endocytosis, and attenuates macrophage proliferation

Colony-stimulating factor-1 (CSF-1) activation of the CSF-1 receptor (CSF-1R) causes Cbl protooncoprotein tyrosine phosphorylation, Cbl-CSF-1R association and their simultaneous multiubiquitination at the plasma membrane. The CSF-1R is then rapidly internalized and degraded, whereas Cbl is deubiquitinated in the cytoplasm without being degraded. We have used primary macrophages from gene-targeted mice to study the role of Cbl. Cbl-/- macrophages form denser colonies and, at limiting CSF-1 concentrations, proliferate faster than Cbl+/+ macrophages. Their CSF-1Rs fail to exhibit multiubiquitination and a second wave of tyrosine phosphorylation previously suggested to be involved in preparation of the CSF-1-CSF-1R complex for endocytosis. Consistent with this result, Cbl-/- macrophage cell surface CSF-1-CSF-1R complexes are internalized more slowly, yet are still lysosomally degraded, and the CSF-1 utilization by Cbl-/- macrophages is reduced approximately 2-fold. Thus, attenuation of proliferation by Cbl is associated with its positive regulation of the coordinated multiubiquitination and endocytosis of the activated CSF-1R, and a reduction in the time that the CSF-1R signals from the cell surface. The results provide a paradigm for studies of the mechanisms underlying Cbl attenuation of proliferative responses induced by ligation of receptor tyrosine kinases.

Cost-benefit comparison: holmium laser versus electrocautery in arthroscopic acromioplasty

This prospective study was designed to measure the costs and benefits of using a laser rather than electrocautery for soft tissue resection during arthroscopic shoulder decompression. Forty-nine shoulders with refractory Neer stage II impingement (persistent fibrosis and tendinitis) were divided into 2 groups. The composition of the 2 groups was similar with regard to sex, worker's compensation status, dominant arm involvement, duration of symptoms, and length of conservative treatment. In one group, electrocautery was used to ablate the bursa and periosteum, release the coracoacromial ligament, and maintain hemostasis. In the other group, a laser was used in place of electrocautery. Patients had been evaluated preoperatively with 2 functional scoring systems. The patients were reexamined at 1 week and at 1, 2, 3, 6, and 12 months after surgery. There were no differences between the groups with regard to functional outcome or satisfaction. There was also no difference in terms of estimated blood loss or operative time. However, there was a statistically significant difference in total hospital charges between groups, with the laser group having a 23% higher hospital bill. On the basis of these results, it is concluded that there was no medical benefit to laser-assisted arthroscopic subacromial decompression but there was an increased monetary cost.

The effect of stimulatory electrode placement on F-wave latency measurements

BACKGROUND AND PURPOSE

The purpose of this study was to compare the effects of two commonly used stimulating electrode placements on F-wave latency.

SUBJECTS

Fifty healthy subjects aged 20 to 47 years were tested.

METHODS

F-waves were obtained from median and ulnar nerves bilaterally. A total of 200 nerves were tested.

RESULTS

A paired t-test indicated a statistically significant difference in F-wave latency between the two stimulating electrode placements. Stepwise linear regression equations demonstrated that our results were consistent with previously published studies.

CONCLUSION AND DISCUSSION

Although a statistically significant difference exists between the two techniques, the magnitude of the difference is not likely to be clinically important. Therefore, the most important factor may be to use a consistent technique when investigating potential neuropathies.

Tissue hyperplasia and enhanced T-cell signalling via ZAP-70 in c-Cbl-deficient mice

The c-Cbl protein is tyrosine phosphorylated and forms complexes with a wide range of signalling partners in response to various growth factors. How c-Cbl interacts with proteins, such as Grb2, phosphatidylinositol 3-kinase, and phosphorylated receptors, is well understood, but its role in these complexes is unclear. Recently, the Caenorhabditis elegans Cbl homolog, Sli-1, was shown to act as a negative regulator of epidermal growth factor receptor signalling. This finding forced a reassessment of the role of Cbl proteins and highlighted the desirability of testing genetically whether c-Cbl acts as a negative regulator of mammalian signalling. Here we investigate the role of c-Cbl in development and homeostasis in mice by targeted disruption of the c-Cbl locus. c-Cbl-deficient mice were viable, fertile, and outwardly normal in appearance. Bone development and remodelling also appeared normal in c-Cbl mutants, despite a previously reported requirement for c-Cbl in osteoclast function. However, consistent with a high level of expression of c-Cbl in the hemopoietic compartment, c-Cbl-deficient mice displayed marked changes in their hemopoietic profiles, including altered T-cell receptor expression, lymphoid hyperplasia, and primary splenic extramedullary hemopoiesis. The mammary fat pads of mutant female mice also showed increased ductal density and branching compared to those of their wild-type littermates, indicating an unanticipated role for c-Cbl in regulating mammary growth. Collectively, the hyperplastic histological changes seen in c-Cbl mutant mice are indicative of a normal role for c-Cbl in negatively regulating signalling events that control cell growth. Consistent with this view, we observed greatly increased intracellular protein tyrosine phosphorylation in thymocytes following CD3epsilon cross-linking. In particular, phosphorylation of ZAP-70 kinase in thymocytes was uncoupled from a requirement for CD4-mediated Lck activation. This study provides the first biochemical characterization of any organism that is deficient in a member of this unique protein family. Our findings demonstrate critical roles for c-Cbl in hemopoiesis and in controlling cellular proliferation and signalling by the Syk/ZAP-70 family of protein kinases.

Subjects with seasonal allergic rhinitis and nonrhinitic subjects react differentially to nasal provocation with chlorine gas

BACKGROUND

Nasal irritation and associated symptoms (nasal congestion, rhinorrhea, and sinus headache) are important elements of the response to indoor and outdoor air pollution. Marked interindividual variability in such symptoms has been suggested clinically and epidemiologically, but little experimental data exist on this issue.

OBJECTIVE

We sought to test the hypothesis that subjects with seasonal allergic rhinitis (SAR) exhibit a more marked physiologic response (congestion) after nasal irritant provocation than do nonrhinitic subjects.

METHODS

We studied eight subjects with SAR and eight nonrhinitic subjects; subjects with SAR were studied out of season. In a single-blind crossover study, subjects had their nasal airway resistance (NAR) measured in triplicate before, immediately after, and 15 minutes after a 15-minute exposure to either filtered air or 0.5 ppm chlorine in filtered air, administered through a nasal mask in a climate-controlled chamber. Log-transformed NAR values were analyzed in a repeated-measures analysis of variance model, with confirmatory testing using paired t tests.

RESULTS

The net (chlorine minus air day) percent change in NAR from baseline (before exposure) to immediately after exposure was +24% in the SAR group and +3% in the nonrhinitic group (p < 0.05). The corresponding net changes from baseline to 15 minutes after exposure were +21% in the SAR group and -1% in the nonrhinitic group (p < 0.05).

CONCLUSIONS

The observed augmented nasal congestive response of subjects with SAR versus nonrhinitic subjects to a controlled low-level chemical irritant provocation is consistent with epidemiologic surveys showing a higher prevalence of nasal symptoms among subjects with SAR than nonrhinitic subjects in environments involving irritant air pollutants.

Congenital optic tract syndrome: magnetic resonance imaging and scanning laser ophthalmoscopy findings

Lesions of the optic tract produce a distinctive pattern of optic atrophy and visual field loss and may be due to either congenital or acquired causes. We report a case of a congenital optic tract syndrome and correlate the magnetic resonance imaging findings with the appearance of nerve fiber layer defects found by confocal scanning laser ophthalmoscopy.

Bilateral diffuse uveal melanocytic proliferation simulating an arteriovenous fistula

Bilateral diffuse uveal melanocytic proliferation is a rare paraneoplastic syndrome that causes visual loss in patients with systemic carcinoma. We report the case of a patient with this syndrome whose initial presentation and striking anterior segment findings mimicked that of an arteriovenous fistula.

Paraneoplastic retinopathy: a novel autoantibody reaction associated with small-cell lung carcinoma

We present the case of a 74-year-old man with rapidly progressive bilateral visual loss, optic disc pallor, retinal arteriolar attenuation, and an abnormal electroretinogram with a 90% reduction in cone function and a 50% reduction in rod function. He was examined for a suspected cancer-associated retinopathy (CAR). Although he was found not to have expressed the previously reported 23-kd CAR antibody, high titers were found of an antibody to a 60-kd retinal protein, which as yet remains unidentified. An initial clinical search for an underlying cancer was unsuccessful, but 2 months later a mediastinal mass was found on chest x-rays, and biopsy confirmed a diagnosis of small-cell lung carcinoma. Combined therapy with oral corticosteroids and plasmapheresis resulted in a recovery of vision from counting fingers to 20/200 in the right eye and 20/40 to 20/25 in the left eye. Conventional chemotherapeutic management of the small-cell lung carcinoma was instituted, and the modest visual recovery was maintained. The visual improvement as well as lung tumor regression were accompanied by a decline in antibody titers from 1:2,000 pretreatment to 1:200 during the course of therapy. The absence of reactivity with the previously described 23-kd retinal antigen of the CAR syndrome does not exclude the diagnosis of paraneoplastic retinopathy in patients fitting the clinical profile of this disease.

Multi-disciplinary clinical study of Smith-Magenis syndrome (deletion 17p11.2)

Smith-Magenis syndrome (SMS) is a multiple congenital anomaly, mental retardation (MCA/MR) syndrome associated with deletion of chromosome 17 band p11.2. As part of a multi-disciplinary clinical, cytogenetic, and molecular approach to SMS, detailed clinical studies including radiographic, neurologic, developmental, ophthalmologic, otolaryngologic, and audiologic evaluations were performed on 27 SMS patients. Significant findings include otolaryngologic abnormalities in 94%, eye abnormalities in 85%, sleep abnormalities (especially reduced REM sleep) in 75%, hearing impairment in 68% (approximately 65% conductive and 35% sensorineural), scoliosis in 65%, brain abnormalities (predominantly ventriculomegaly) in 52%, cardiac abnormalities in at least 37%, renal anomalies (especially duplication of the collecting system) in 35%, low thyroxine levels in 29%, low immunoglobulin levels in 23%, and forearm abnormalities in 16%. The measured IQ ranged between 20-78, most patients falling in the moderate range of mental retardation at 40-54, although several patients scored in the mild or borderline range. The frequency of these many abnormalities in SMS suggests that patients should be evaluated thoroughly for associated complications both at the time of diagnosis and at least annually thereafter.

Application of frameless stereotaxy to pedicle screw fixation of the spine

Interactive frameless stereotaxy has been successfully applied to intracranial surgery. It has contributed to the improved localization of deep-seated brain lesions and has demonstrated a potential for reducing both operative time and morbidity. However, it has not been as effectively applied to spinal surgery. The authors describe the application of frameless stereotactic techniques to spinal surgery, specifically pedicle screw fixation of the lumbosacral spine. Preoperative axial computerized tomography (CT) images of the appropriate spinal segments are obtained and loaded onto a high-speed graphics supercomputer workstation. Intraoperatively, these images can be linked to the appropriate spinal anatomy by a sonic localization digitizer device that is interfaced with the computer workstation. This permits the surgeon to place a pointing device (sonic wand) on any exposed spinal bone landmark in the operative field and obtain multiplanar reconstructed CT images projected in near-real time on the workstation screen. The images can be manipulated to assist the surgeon in determining the proper entry point for a pedicle screw as well as defining the appropriate trajectory in the axial and sagittal planes. It can also define the correct screw length and diameter for each pedicle to be instrumented. The authors applied this device to the insertion of 150 screws into the lumbosacral spines of 30 patients. One hundred forty-nine screws were assessed to be satisfactorily placed by postoperative CT and plain film radiography. In this report the authors discuss their use of this device in the clinical setting and review their preliminary results of frameless stereotaxy applied to spinal surgery. On the basis of their findings, the authors conclude that frameless stereotactic technology can be successfully applied to spinal surgery.

Antibiotic penetration into cervical discs

Antibiotics are frequently prophylactically administered in surgical procedures to reduce the incidence of infection. The penetration of antibiotics into lumbar discs has been studied with mixed results, but penetration into cervical discs has not been reviewed. In this study, we examined the penetration of two commonly used antibiotics, oxacillin and cefazolin, into cervical discs. Eighteen patients with a total of 30 discs removed were studied. Two groups, each consisting of four patients with five discs removed, received either 1 g of oxacillin or 1 g of cefazolin by a single, preoperative intravenous infusion. Two other groups, each consisting of five patients with 10 discs removed, received either 2 g of oxacillin or 2 g of cefazolin, also by a single, preoperative intravenous infusion. A blood specimen, from which serum antibiotic levels were determined, was obtained from each patient simultaneously with each discectomy. The time interval between the antibiotic infusion and discectomy/phlebotomy was also recorded. Antibiotic levels were detected in all discs removed but were quantifiable in only 12. Nine of these 12 had been exposed to cefazolin. Of these nine discs, one was from a patient who had received 1 g whereas the other eight were from patients who had received 2 g of cefazolin. This represents 80% of the removed discs exposed to 2 g of cefazolin (10 discs total) and 20% exposed to 1 g (5 discs total). The remaining three discs with quantifiable antibiotic levels had been exposed to 2 g of oxacillin, which represents 30% of the discs (10 total) exposed to that dose of oxacillin. Although cervical disc space infections are rare, they are serious.(ABSTRACT TRUNCATED AT 250 WORDS)