Current and Future Applications of Fluorescence Guidance in Orthopaedic Surgery

Fluorescence-guided surgery (FGS) is an evolving field that seeks to identify important anatomic structures or physiologic phenomena with helpful relevance to the execution of surgical procedures. Fluorescence labeling occurs generally via the administration of fluorescent reporters that may be molecularly targeted, enzyme-activated, or untargeted, vascular probes. Fluorescence guidance has substantially changed care strategies in numerous surgical fields; however, investigation and adoption in orthopaedic surgery have lagged. FGS shows the potential for improving patient care in orthopaedics via several applications including disease diagnosis, perfusion-based tissue healing capacity assessment, infection/tumor eradication, and anatomic structure identification. This review highlights current and future applications of fluorescence guidance in orthopaedics and identifies key challenges to translation and potential solutions.

A systematic review of the effects of temperature and precipitation on pollen concentrations and season timing, and implications for human health

Climate and weather directly impact plant phenology, affecting airborne pollen. The objective of this systematic review is to examine the impacts of meteorological variables on airborne pollen concentrations and pollen season timing. Using PRISMA methodology, we reviewed literature that assessed whether there was a relationship between local temperature and precipitation and measured airborne pollen. The search strategy included terms related to pollen, trends or measurements, and season timing. For inclusion, studies must have conducted a correlation analysis of at least 5 years of airborne pollen data to local meteorological data and report quantitative results. Data from peer-reviewed articles were extracted on the correlations between seven pollen indicators (main pollen season start date, end date, peak date, and length, annual pollen integral, average daily pollen concentration, and peak pollen concentration), and two meteorological variables (temperature and precipitation). Ninety-three articles were included in the analysis out of 9,679 articles screened. Overall, warmer temperatures correlated with earlier and longer pollen seasons and higher pollen concentrations. Precipitation had varying effects on pollen concentration and pollen season timing indicators. Increased precipitation may have a short-term effect causing low pollen concentrations potentially due to "wash out" effect. Long-term effects of precipitation varied for trees and weeds and had a positive correlation with grass pollen levels. With increases in temperature due to climate change, pollen seasons for some taxa in some regions may start earlier, last longer, and be more intense, which may be associated with adverse health impacts, as pollen exposure has well-known health effects in sensitized individuals.

Assessing Shoulder Biomechanics of Healthy Elderly Individuals During Activities of Daily Living Using Inertial Measurement Units: High Maximum Elevation Is Achievable but Rarely Used

Current shoulder clinical range of motion (ROM) assessments (e.g., goniometric ROM) may not adequately represent shoulder function beyond controlled clinical settings. Relative inertial measurement unit (IMU) motion quantifies ROM precisely and can be used outside of clinic settings capturing "real-world" shoulder function. A novel IMU-based shoulder elevation quantification method was developed via IMUs affixed to the sternum/humerus, respectively. This system was then compared to in-laboratory motion capture (MOCAP) during prescribed motions (flexion, abduction, scaption, and internal/external rotation). MOCAP/IMU elevation were equivalent during flexion (R2 = 0.96, μError = 1.7 deg), abduction (R2 = 0.96, μError = 2.9 deg), scaption (R2 = 0.98, μError = -0.3 deg), and internal/external rotation (R2 = 0.90, μError = 0.4 deg). When combined across movements, MOCAP/IMU elevation were equal (R2 = 0.98, μError = 1.4 deg). Following validation, the IMU-based system was deployed prospectively capturing continuous shoulder elevation in 10 healthy individuals (4 M, 69 ± 20 years) without shoulder pathology for seven consecutive days (13.5 ± 2.9 h/day). Elevation was calculated continuously daily and outcome metrics included percent spent in discrete ROM (e.g., 0-5 deg and 5-10 deg), repeated maximum elevation (i.e., >10 occurrences), and maximum/average elevation. Average elevation was 40 ± 6 deg. Maximum with >10 occurrences and maximum were on average 145-150 deg and 169 ± 8 deg, respectively. Subjects spent the vast majority of the day (97%) below 90 deg of elevation, with the most time spent in the 25-30 deg range (9.7%). This study demonstrates that individuals have the ability to achieve large ROMs but do not frequently do so. These results are consistent with the previously established lab-based measures. Moreover, they further inform how healthy individuals utilize their shoulders and may provide clinicians a reference for postsurgical ROM.

The Cost-Effectiveness of Reverse Total Shoulder Arthroplasty Versus Open Reduction Internal Fixation for Proximal Humerus Fractures in the Elderly

BACKGROUND

Open reduction and internal fixation (ORIF) of proximal humerus fractures in elderly individuals (age >70) carries a relatively high short-term complication and reoperation rate but is generally durable once healed. Reverse total shoulder arthroplasty (RTSA) for fractures may be associated with superior short-term quality of life but carries the lifelong liabilities of joint replacement. The tradeoff between short and long-term risks, coupled with disparities in quality of life and cost, makes this clinical decision amenable to cost-effectiveness analysis.

METHODS

A Markov state-transition model was constructed with a base case of a 75 year-old patient. Reoperation rates, quality of life values, mortality rates, and costs were based upon published literature. The model was run until all patients had died to simulate the accumulated costs and benefits.

RESULTS

RTSA was associated with greater quality of life (7.11 QALYs) than ORIF (6.22 QALYs). RTSA was cost-effective with an incremental cost-effectiveness ratio of $3,945/QALY and $27,299/ QALY from payor and hospital perspectives, respectively. RTSA was favored and cost-effective at any age above 65 and any Charlson Score. The model was sensitive to the utility of both procedures.

CONCLUSION

RTSA resulted in a higher quality of life and was cost-effective in comparison to ORIF for elderly patients.Level of Evidence: III.

Continuously monitoring shoulder motion after total shoulder arthroplasty: maximum elevation and time spent above 90° of elevation are critical metrics to monitor

BACKGROUND

Traditional clinical shoulder range-of-motion (ROM) measurement methods (ie, goniometry) have limitations assessing ROM in total shoulder arthroplasty (TSA) patients. Inertial measurement units (IMUs) are superior; however, further work is needed using IMUs to longitudinally assess shoulder ROM before TSA and throughout post-TSA rehabilitation. Accordingly, the study aims were to prospectively capture shoulder elevation in TSA patients and to compare the results with healthy controls. We hypothesized that patients would have reduced maximum elevation before TSA compared with controls but would have improved ROM after TSA.

METHODS

A validated IMU-based shoulder elevation quantification method was used to continuously monitor 10 healthy individuals (4 men and 6 women; mean age, 69 ± 20 years) without shoulder pathology and 10 TSA patients (6 men and 4 women; mean age, 70 ± 8 years). Controls wore IMUs for 1 week. Patients wore IMUs for 1 week before TSA, for 6 weeks at 3 months after TSA, and for 1 week at 1 year after TSA. Shoulder elevation was calculated continuously, broken into 5° angle "bins" (0°-5°, 5°-10°, and so on), and converted to percentages. The main outcome measures were binned movement percentage, maximum elevation, and average elevation. Patient-reported outcome measures and goniometric ROM were also captured.

RESULTS

No demographic differences were noted between the cohorts. Average elevation was not different between the cohorts at any time. Control maximum elevation was greater than pre-TSA and post-TSA week 1 and week 2 values. Time under 30° and time above 90° were equal between the cohorts before TSA. After TSA, patients showed decreased time under 30° and increased time above 90°.

DISCUSSION

This study demonstrates that acute and chronic recovery after TSA can be assessed via maximum elevation and time above 90°, respectively. These results inform how healthy individuals and patients use their shoulders before and after TSA.

Identifying regional characteristics influencing variation in the utilization of rotator cuff repair in the United States

BACKGROUND

There is a lack of consensus regarding indications for surgical management of rotator cuff disease, which can lead to increased regional variation. The objectives of this study were to describe the geographic variation in rates of rotator cuff repair (RCR) in the United States over time and to identify regional characteristics associated with utilization.

METHODS

The United States was divided into 306 hospital referral regions. The adjusted per capita RCR rate was calculated using procedural counts derived from the Medicare Part B Carrier File from 2004-2014. Population-weighted multivariable regression was used to identify regional characteristics independently associated with utilization in 2014.

RESULTS

In 2014, an 8-fold difference in rates of RCR was found between regions. Between 2010 and 2014, the overall rate of RCR grew only 3.6% and regional variation decreased. Higher regional utilization of several other orthopedic procedures (P < .02), as well as the regional supply of orthopedic surgeons (P = .002), was independently associated with significantly increased utilization. The South, Southeast, and Southwest were independently associated with significantly higher utilization (P < .001) compared with the Northeast. A higher prevalence of resident physicians, a marker of the academic presence within a region, was independently associated with decreased utilization (P < .001).

CONCLUSION

Utilization of RCR has increased substantially over the past decade, but the rate of growth appears to be slowing. RCR remains a procedure with significant regional variation, and increased utilization across regions is associated with higher orthopedic surgeon supply and increased rates of other orthopedic procedures.

Patterns of Opioid Use in the 12 Months Following Geriatric Fragility Fractures: A Population-Based Cohort Study

OBJECTIVES

Fractures of the hip, distal radius, and proximal humerus are common in the Medicare population. This study's objective was to characterize patterns and duration of opioid use, including regional variations in use, after both surgical and nonoperative management.

DESIGN

Population-based cohort study.

SETTING AND PARTICIPANTS

A cohort of opioid-naïve community-dwelling US Medicare beneficiaries who survived a hip, distal radius, or proximal humerus fracture between January 1, 2007 and December 31, 2010. Cohort members were required to be opioid-naïve for 4 months prior to fracture.

MEASURES

We analyzed the proportion of patients with an active opioid prescription in each month following the index fracture, and report continued fills at 12 months postfracture. We also compared opioid prescription use in fractures treated surgically and nonsurgically and characterized state-level variation in opioid prescription use at 3 months postfracture.

RESULTS

There were 91,749 patients included in the cohort. Hip fracture patients had the highest rate of opioid use at 12 months (6.4%), followed by proximal humerus (5.7%), and distal radius (3.7%). Patients who underwent surgical fixation of proximal humerus and wrist fractures had higher rates of opioid use in each of the first 12 postoperative months compared with those managed nonoperatively. There was significant variation of opioid use at the state level, ranging from 7.6% to 18.2% of fracture patients filling opioid prescriptions 3 months after the index fracture.

CONCLUSIONS/IMPLICATIONS

Opioid-naïve patients sustaining fragility fractures of the hip, proximal humerus, or distal radius are at risk to remain on opioid medications 12 months after their index injury, and surgical management of proximal humerus and distal radius fractures increases opioid use in the 12 months after the index fracture. There is significant state-level variation in opiate consumption after index fracture in nonvertebral geriatric fragility fractures. Opportunity exists for targeted quality improvement efforts to reduce the variation in opioid use following common geriatric fragility fractures.

Analysis of polyethylene wear of reverse shoulder components: A validated technique and initial clinical results

One of the most prevalent phenomena associated with reverse total shoulder arthroplasty (rTSA) is scapular notching. Current methods examine only the damage to the scapula and no methods are available for quantifying the total wear volume of the polyethylene humeral bearing. Quantifying the polyethylene material loss may provide insight into the mechanism for scapular notching and into the particle dose delivered to the patient. A coordinate measurement machine (CMM) and custom computer algorithms were employed to quantify the volumetric wear of polyethylene humeral bearings. This technique was validated using two never-implanted polyethylene humeral liners with a controlled amount of wear in clinically relevant locations. The technique was determined to be accurate to within 10% of the known value and within 5 mm³ of the gravimetrically determined values. Following validation, ten retrieved polyethylene humeral liners were analyzed to determine a baseline for future clinical tests. Four of the ten polyethylene humeral liners showed visible and measureable wear volumes ranging from 40 to 90 mm³ total with a maximum wear rate as high as 470 mm³ /year in one short duration and significantly damaged humeral liner. This validated technique has the potential to relate patient outcomes such as scapular notching grades to polyethylene release into the body. While the total wear volumes are less than reported in literature for cases of osteolysis in knee and hip patients, dosages are well within the osteolytic thresholds that have been suggested, indicating that osteolysis may be a clinical concern in the shoulder. This work provides the basis for future studies that relate volumetric wear to patient outcomes. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:980-987, 2017.

Falling Down on the Job: Evaluation and Treatment of Fall Risk Among Older Adults With Upper Extremity Fragility Fractures

BACKGROUND

Clinical practice guidelines recommend fall risk assessment and intervention for older adults who sustain a fall-related injury to prevent future injury and mobility decline.

OBJECTIVE

The aim of this study was to describe how often Medicare beneficiaries with upper extremity fracture receive evaluation and treatment for fall risk.

DESIGN

Observational cohort.

METHODS

Participants were fee-for-service beneficiaries age 66 to 99 treated as outpatients for proximal humerus or distal radius/ulna ("wrist") fragility fractures. -Participants were studied using Carrier and Outpatient Hospital files. The proportion of patients evaluated or treated for fall risk up to 6 months after proximal humerus or wrist fracture from 2007-2009 was examined based on evaluation, treatment, and diagnosis codes. Time to evaluation and number of treatment sessions were calculated. Logistic regression was used to analyze patient characteristics that predicted receiving evaluation or treatment. Narrow (gait training) and broad (gait training or therapeutic exercise) definitions of service were used.

RESULTS

There were 309,947 beneficiaries who sustained proximal humerus (32%) or wrist fracture (68%); 10.7% received evaluation or treatment for fall risk or gait issues (humerus: 14.2%; wrist: 9.0%). Using the broader definition, the percentage increased to 18.5% (humerus: 23.4%; wrist: 16.3%). Factors associated with higher likelihood of services after fracture were: evaluation or treatment for falls or gait prior to fracture, more comorbidities, prior nursing home stay, older age, humerus fracture (vs wrist), female sex, and white race.

LIMITATIONS

Claims analysis may underestimate physician and physical therapist fall assessments, but it is not likely to qualitatively change the results.

CONCLUSIONS

A small proportion of older adults with upper extremity fracture received fall risk assessment and treatment. Providers and health systems must advance efforts to provide timely evidence-based management of fall risk in this population.

Patterns of Prescription Drug Use Before and After Fragility Fracture

IMPORTANCE

Patients who have a fragility fracture are at high risk for subsequent fractures. Prescription drugs represent 1 factor that could be modified to reduce the risk of subsequent fracture.

OBJECTIVE

To describe the use of prescription drugs associated with fracture risk before and after fragility fracture.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective cohort study conducted between February 2015 and March 2016 using a 40% random sample of Medicare beneficiaries from 2007 through 2011 in general communities throughout the United States. A total of 168 133 community-dwelling Medicare beneficiaries who survived a fracture of the hip, shoulder, or wrist were included. Cohort members were required to be enrolled in fee-for-service Medicare with drug coverage (Parts A, B, and D) and to be community dwelling for at least 30 days in the immediate 4-month postfracture period.

EXPOSURES

Prescription drug use during the 4-month period before and after a fragility fracture.

MAIN OUTCOMES AND MEASURES

Prescription fills for drug classes associated with increased fracture risk were measured using Part D retail pharmacy claims. These were divided into 3 categories: drugs that increase fall risk; drugs that decrease bone density; and drugs with unclear fracture risk mechanism. Drugs that increase bone density were also tracked.

RESULTS

A total of 168 133 patients with a fragility fracture (141 569 women; 84.2%) met the inclusion criteria for this study; 91.8% were white. Across all fracture types, the mean (SD) age was 80.0 (7.7) years, and 53.2% of the fracture cohort was hospitalized at the time of the index fracture, although this varied significantly depending on fracture type (100% of hip fractures, 8.2% of wrist fractures, and 15.0% of shoulder fractures). The frequency of discharge to an institution for rehabilitation following hospitalization also varied by fracture type, but the mean (SD) duration of acute rehabilitation did not: 28.1 (19.8) days. Most patients were exposed to at least 1 nonopiate drug associated with increased fracture risk in the 4 months before fracture (77.1% of hip, 74.1% of wrist, and 75.9% of shoulder fractures). Approximately 7% of these patients discontinued this drug exposure after the fracture, but this was offset by new users after fracture. Consequently, the proportion of the cohort exposed following fracture was unchanged (80.5%, 74.3%, and 76.9% for hip, wrist, and shoulder, respectively). There was no change in the average number of fracture-associated drugs used. This same pattern of use before and after fracture was observed across all 3 drug mechanism categories. Use of drugs to strengthen bone density was uncommon (≤25%) both before and after fracture.

CONCLUSIONS AND RELEVANCE

Exposure to prescription drugs associated with fracture risk is infrequently reduced following fragility fracture occurrence. While some patients eliminate their exposure to drugs associated with fracture, an equal number initiate new high-risk drugs. This pattern suggests there is a missed opportunity to modify at least one factor contributing to secondary fractures.

Fatigue failure of reverse shoulder humeral tray components of a single design

BACKGROUND

Modularity in shoulder arthroplasty provides surgical flexibility and facilitates less-complex revision surgery. Modular designs must fit in the glenohumeral joint space, necessitating minimal thickness and careful material selection. The potential for fatigue fracture is higher, and fatigue fracture has been experienced by patients. The purpose of this study was to determine the impact of geometry and materials used for modular humeral trays from a single manufacturer.

METHODS

We consecutively retrieved 8 humeral trays of nearly identical designs: 4 Ti-6Al-4V (Ti) and 4 CoCrMo (CoCr). Optical microscopy and scanning electron microscopy were used, along with metallurgical techniques. Finite element and fatigue analyses of the stresses at the humeral tray taper informed observation interpretation.

RESULTS

Two Ti devices were revised for in vivo fracture. Scanning electron microscopy showed cracking in the other 2 Ti trays and no evidence of cracking in the CoCr components. A geometric difference in the CoCr devices resulted in a 25% decreased stress under simulated activities of daily living. Accounting for the tray material properties, the fatigue failure envelope ranged from 1000 to 1 million cycles for Ti and from 30,000 to >10 million cycles for CoCr.

CONCLUSIONS

All Ti humeral tray retrievals fractured in vivo or were cracked at the taper fillet. No CoCr retrievals showed signs of cracking. Finite element and fatigue analyses predict a 10-fold lifetime increase for the CoCr devices compared with the Ti devices. This study shows that fatigue failure is possible for some reverse shoulder components and is likely exacerbated by fillet radius, tray thickness, and material choice.

Application of a Novel Brain Arteriovenous Malformation Endovascular Grading Scale for Transarterial Embolization

BACKGROUND AND PURPOSE

The advent of modern neuroendovascular techniques has highlighted the need for a simple, effective, and reliable brain arteriovenous malformation endovascular grading scale. A novel scale of this type has recently been described. It incorporates the number of feeding arteries, eloquence, and the presence of an arteriovenous fistula component. Our aim is to assess the validity of this grading scale.

MATERIALS AND METHODS

We retrospectively reviewed all suspected brain arteriovenous malformations at Massachusetts General Hospital from 2005 to 2013, identifying 126 patients who met the inclusion criteria. Spearman correlations between endovascular and Spetzler-Martin grading scales and long-term outcomes were performed. Median endovascular grades were compared between treatment modalities and endovascular outcomes. Binary regression analysis was performed with major endovascular complications as a dichotomized dependent variable. Intraclass correlation coefficients were calculated for interobserver reliability of the endovascular grading scale.

RESULTS

A significant Spearman correlation between the endovascular grade and the Spetzler-Martin grade was demonstrated (ρ = 0.5, P < .01). Differences in the median endovascular grades between the endovascular cure (median = 2) and endovascular complication groups (median = 4) (P < .05) and between the endovascular cure and successful multimodal treatment groups (median = 3) (P < .05) were demonstrated. The endovascular grade was the only independent predictor of complications (OR = 0.5, P < .01). The intraclass correlation coefficient of the endovascular grade was 0.71 (P < .01).

CONCLUSIONS

Validation of a brain arteriovenous malformation endovascular grading scale demonstrated that endovascular grades of ≤II were associated with endovascular cure, while endovascular grades of ≤III were associated with multimodal cure or significant lesion reduction and favorable outcome. The endovascular grade provides useful information to refine risk stratification for endovascular and multimodal treatment.

Reverse shoulder arthroplasty for treatment of proximal humeral fractures in older adults: a systematic review

BACKGROUND

Displaced proximal humeral fractures have traditionally been treated with hemiarthroplasty in older adults, but sometimes hemiarthroplasty results in poor functional outcomes due to rotator cuff deficiency. Reverse shoulder arthroplasty (RSA) can offer potentially improved outcomes in these situations. We assessed the functional outcomes of older adults treated with RSA for proximal humeral fractures compared with hemiarthroplasty.

METHODS

We searched MEDLINE, the Cochrane Central Register of Controlled Trials, EMBASE, and 3 clinical trials registries. We included all studies treating proximal humeral fractures with RSA in adults with a mean age older than 60 years and 1 year of follow-up. We calculated weighted mean differences (WMD) for range of motion and standardized mean differences (SMD) for shoulder scores. Postoperative complications were evaluated qualitatively.

RESULTS

Fifteen studies met inclusion criteria, including 377 patients treated with RSA and 504 patients treated with hemiarthroplasty. In controlled studies, the RSA group had improved forward flexion (WMD, 21°;, P = .02) and functional outcome scores (SMD, 0.44; P = .005) compared with the hemiarthroplasty group but decreased external rotation (WMD, -5°; P < .0001). Postoperative complications were similar between the 2 groups.

CONCLUSION

RSA results in improved forward flexion and functional outcome scores compared with hemiarthroplasty for older adults with proximal humeral fractures. Complications do not appear to be appreciably higher in the RSA group in the existing follow-up. The results of this review suggest that RSA is a reasonable alternative for treating older adults with proximal humeral fractures, but more research and longer follow-up are needed.

LEVEL OF EVIDENCE

Level IV, systematic review.

Functional improvement after humeral shaft nonunion in a patient with glenohumeral ankylosis

Functionally limiting heterotopic ossification about the shoulder represents an uncommon clinical entity, which has been most commonly reported as a consequence of prolonged immobilization in intensive care unit patients. Severe cases may result in complete glenohumeral ankylosis, with resultant upper extremity motion through the scapulothoracic joint, and significant functional consequences. We report the case of a 72-year-old male with spontaneous glenohumeral ankylosis who suffered a humeral shaft fracture with resultant painless nonunion. Motion through the nonunion site caused significant subjective functional improvements, increased range of motion, and the ability to complete his activities of daily living. Patients with limited shoulder range of motion may be at higher risk for humeral fractures and nonunion. These patients, however, may experience improved function due to increased upper extremity range of motion through the nonunion site.

Quality of osteoporosis care of older Medicare recipients with fragility fractures: 2006 to 2010

OBJECTIVES

To assess uptake of postfracture care guidelines in community-dwelling Medicare recipients with fractures.

DESIGN

Retrospective observational cohort study.

SETTING

Claims-based study using U.S. Medicare administrative inpatient, outpatient (2003-2010), and prescription (2006-2010) data.

PARTICIPANTS

Individuals aged 68 and older who survived at least 12 months after a fracture of the hip, radius, or humerus.

MEASUREMENTS

Poisson regression modeled factors, including participant characteristics, comorbidities and hospital referral region (HRR), associated with bone density testing or osteoporosis pharmacotherapy in the 6 months after fracture. Models were repeated for participants with no osteoporosis care observed before fracture (attention naïve).

RESULTS

In 61,832 individuals with fractures, mean age was 80.6, 87.0% were female, 88.5% were white, 2.6% were black, and 62.1% were attention naïve at the time of fracture; 21.8% received testing, pharmacotherapy, or both in the 6 months after fracture. In adjusted models, factors associated with significantly lower likelihood of receiving this care were black race, male sex, and an upper extremity fracture (vs hip). In models restricted to attention-naïve participants, the same factors were associated with lower relative risk of receiving care. Adjusted HRR-level care rates ranged from 14.7% to 22.9% (10th to 90th percentile). The proportion receiving care increased from 2006 to 2009.

CONCLUSION

Postfracture osteoporosis care was uncommon, particularly in black and male participants. Care increased over time, but for most, a fracture was insufficient to trigger effective secondary prevention, especially for participants who were not receiving prefracture osteoporosis attention. Clinicians and policy-makers must consider effective remedies to this persistent care gap.

N-methyl-d-aspartate receptors, learning and memory: chronic intraventricular infusion of the NMDA receptor antagonist d-AP5 interacts directly with the neural mechanisms of spatial learning

Three experiments were conducted to contrast the hypothesis that hippocampal N-methyl-d-aspartate (NMDA) receptors participate directly in the mechanisms of hippocampus-dependent learning with an alternative view that apparent impairments of learning induced by NMDA receptor antagonists arise because of drug-induced neuropathological and/or sensorimotor disturbances. In experiment 1, rats given a chronic i.c.v. infusion of d-AP5 (30 mm) at 0.5 μL/h were selectively impaired, relative to aCSF-infused animals, in place but not cued navigation learning when they were trained during the 14-day drug infusion period, but were unimpaired on both tasks if trained 11 days after the minipumps were exhausted. d-AP5 caused sensorimotor disturbances in the spatial task, but these gradually worsened as the animals failed to learn. Histological assessment of potential neuropathological changes revealed no abnormalities in d-AP5-treated rats whether killed during or after chronic drug infusion. In experiment 2, a deficit in spatial learning was also apparent in d-AP5-treated rats trained on a spatial reference memory task involving two identical but visible platforms, a task chosen and shown to minimise sensorimotor disturbances. HPLC was used to identify the presence of d-AP5 in selected brain areas. In Experiment 3, rats treated with d-AP5 showed a delay-dependent deficit in spatial memory in the delayed matching-to-place protocol for the water maze. These data are discussed with respect to the learning mechanism and sensorimotor accounts of the impact of NMDA receptor antagonists on brain function. We argue that NMDA receptor mechanisms participate directly in spatial learning.

The cost-effectiveness of reverse total shoulder arthroplasty compared with hemiarthroplasty for rotator cuff tear arthropathy

BACKGROUND

Hemiarthroplasty (humeral head replacement [HHR]) and reverse shoulder arthroplasty (RSA) are surgical options for cuff tear arthropathy (CTA). RSA may provide better pain relief and functional outcomes, but it costs more and may have a higher complication rate. The goal of this study was to compare the cost-effectiveness of these two treatments and to use sensitivity analysis to determine the drivers of the model.

MATERIALS AND METHODS

A Markov decision model was used. Outcome and complication probabilities were obtained from existing literature. Costs were based on average Medicare reimbursement and implant prices. Utilities were derived from responses to health state surveys (Short Form 6D) from 31 patients at one institution who underwent RSA or HHR for CTA. Incremental cost-effectiveness ratios were used to compare treatments.

RESULTS

Our model showed RSA could be a cost-effective strategy for treatment of CTA, using $100,000 per quality-adjusted life-year gained as a cutoff and the Short Form 6D for utilities. The model was extremely sensitive to the complication rate and the utility of each procedure and was also sensitive to implant price, with an implant price <$13,000 making RSA cost-effective.

CONCLUSIONS

Currently available cost and outcome data show that RSA could be a cost-effective alternative to HHR for CTA. The cost-effectiveness of RSA depends most on the health utility gained from the operation, the utility lost due to complications from the operation, and the cost of the implant. Dropping the implant price to <$7,000 increases cost-effectiveness to <$50,000 per quality-adjusted life-year gained. Further head-to-head studies evaluating the clinical and quality of life outcomes of these two treatments are warranted.

The cost-effectiveness of single-row compared with double-row arthroscopic rotator cuff repair

BACKGROUND

Interest in double-row techniques for arthroscopic rotator cuff repair has increased over the last several years, presumably because of a combination of literature demonstrating superior biomechanical characteristics and recent improvements in instrumentation and technique. As a result of the increasing focus on value-based health-care delivery, orthopaedic surgeons must understand the cost implications of this practice. The purpose of this study was to examine the cost-effectiveness of double-row arthroscopic rotator cuff repair compared with traditional single-row repair.

METHODS

A decision-analytic model was constructed to assess the cost-effectiveness of double-row arthroscopic rotator cuff repair compared with single-row repair on the basis of the cost per quality-adjusted life year gained. Two cohorts of patients (one with a tear of <3 cm and the other with a tear of ≥3 cm) were evaluated. Probabilities for retear and persistent symptoms, health utilities for the particular health states, and the direct costs for rotator cuff repair were derived from the orthopaedic literature and institutional data.

RESULTS

The incremental cost-effectiveness ratio for double-row compared with single-row arthroscopic rotator cuff repair was $571,500 for rotator cuff tears of <3 cm and $460,200 for rotator cuff tears of ≥3 cm. The rate of radiographic or symptomatic retear alone did not influence cost-effectiveness results. If the increase in the cost of double-row repair was less than $287 for small or moderate tears and less than $352 for large or massive tears compared with the cost of single-row repair, then double-row repair would represent a cost-effective surgical alternative.

CONCLUSIONS

On the basis of currently available data, double-row rotator cuff repair is not cost-effective for any size rotator cuff tears. However, variability in the values for costs and probability of retear can have a profound effect on the results of the model and may create an environment in which double-row repair becomes the more cost-effective surgical option. The identification of the threshold values in this study may help surgeons to determine the most cost-effective treatment.

Characterization of a novel bidirectional distraction spinal cord injury animal model

Scoliosis corrective surgery requires the application of significant multidirectional stress forces, including distraction, for correction of the curved spine deformity and the application of fixation rods. If excessive, spine distraction may result in the development of new neurological deficits, some as severe as permanent paralysis. Current animal models of spinal cord injury, however, are limited to contusion, transection, or unidirectional distraction injuries, which fail to replicate the multidirectional forces that occur during spine corrective surgery. To address such limitation, we designed a novel device that relies on intervertebral grip fixation and linear actuators to induce controllable bidirectional distraction injuries to the spine. The device was tested in three (i.e., 3, 5, and 7 mm) distention paradigms of the rat T9-T11 vertebra, and the resulting injuries were evaluated through electrophysiological, behavioral, and histological analysis. As expected, 3mm bilateral spine distractions showed no neurological deficit. In contrast, those with 5 and 7 mm showed partial and complete paralysis, respectively. The relationship between the severity of the spine distraction and injury to the spinal cord tissue was determined using glial fibrillary acidic protein immunocytochemistry for visualization of reactive astrocytes and labeling of ED1-positive activated macrophages/microglia. Our results demonstrate that this device can produce bidirectional spine distraction injuries with high precision and control and, thus, may be valuable in contributing to the testing of neuroprotective strategies aimed at preventing unintended new neurological damage during corrective spine surgery.

Trends and variation in incidence, surgical treatment, and repeat surgery of proximal humeral fractures in the elderly

BACKGROUND

the treatment of proximal humeral fractures in the elderly remains controversial. Options include nonoperative treatment, open reduction with internal fixation (ORIF), and hemiarthroplasty. Locking plate technology has expanded the indications for ORIF for certain fracture types in osteoporotic bone. This study was performed to characterize the incidence, treatment, and revision surgery of proximal humeral fractures according to geographic region both before (1999 to 2000) and after (2004 to 2005) the introduction of locking plates.

METHODS

we used a 20% sample of Medicare Part-B data and the Medicare denominator file for the years 1998 to 2006. Proximal humeral fractures were identified by Common Procedural Terminology codes for treatment, categorized as nonoperative, ORIF, or hemiarthroplasty. Geographic variation in treatment type was determined with use of 306 hospital referral regions. Odds ratios for revision surgery were calculated by the need for repeat surgery within one year of the index procedure. Rates were adjusted for age, sex, race, and comorbidities.

RESULTS

there were 14,774 proximal humeral fractures in the 20% sample from 1999 to 2000 (an estimated total of 73,870 fractures) and 16,138 fractures in the sample from 2004 to 2005 (an estimated total of 80,690 fractures). The overall age, sex, and race-adjusted incidence of proximal humeral fractures was unchanged from 1999 to 2005 (2.47 vs. 2.48 per 1000 Medicare beneficiaries; p = 0.992). However, the absolute rate of surgically managed proximal humeral fractures rose 3.2 percentage points from 12.5% to 15.7%, a relative increase of 25.6% (p < 0.0001). The relative increase in the percentage of fractures treated with ORIF was 28.5% (p < 0.0001), while the percentage of fractures treated with hemiarthroplasty increased 19.6% (p < 0.0001). There were large regional variations in the proportion treated surgically (range, 0% to 68.18%). The rates of repeat surgery were significantly higher in 2004 to 2005 compared with 1999 to 2000 (odds ratio = 1.47, p = 0.043).

CONCLUSIONS

although the incidence of proximal humeral fractures in the elderly did not change from 1999 to 2005, the rate of surgical treatment increased significantly. The marked regional variation in the rates of surgical treatment highlights the need for better consensus regarding optimal treatment of proximal humeral fractures. Additional research is needed to help to determine which fractures are best treated operatively in order to maximize outcome and minimize the need for revision surgery.

LEVEL OF EVIDENCE

therapeutic Level II. See Instructions to Authors for a complete description of levels of evidence.

Nonoperative treatment of superior labrum anterior posterior tears: improvements in pain, function, and quality of life

BACKGROUND

Although there are multiple reports documenting successful outcomes with operative treatment of superior labrum anterior posterior (SLAP) tears, there are few reports on the results of nonoperative treatment.

HYPOTHESIS

Nonoperative treatment of SLAP tears will result in improved outcomes over pretreatment values using validated, patient-derived outcome instruments.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A total of 371 patients with a diagnosis of labral tear at our institution were mailed a questionnaire that included the following validated, patient-derived outcome assessment instruments: Short Form 36 (SF-36), European Quality of Life measure (EuroQol), visual analog pain scale (VAS), American Shoulder and Elbow Surgeons (ASES) score, and simple shoulder test (SST). Sixty-six surveys did not reach the patients because of incorrect addresses, and 50 surveys were returned, for a 16.4% (50 of 305) response rate. Of the patients with a clinically documented SLAP lesion (positive O'Brien test, pain at the bicipital groove, and positive magnetic resonance imaging) and sufficient follow-up data (minimum 1 year), 39 patients who met the criteria returned the survey and 19 had nonoperative treatment. Twenty patients (51%) from the overall surveyed group were considered nonoperative treatment failures and had arthroscopic surgical reconstruction. Nonoperative treatment consisted of nonsteroidal anti-inflammatory drugs and a physical therapy protocol focused on scapular stabilization exercises and posterior capsular stretching. Statistical analysis was performed using the paired t test; values of P < .05 were considered significant.

RESULTS

At an average follow-up of 3.1 years, function improved significantly (ASES function 30.8 to 45.0 [P < .001]; ASES total 58.5 to 84.7 [P = .001], SST 8.3 to 11.0 [P = .02]) in those patients with successful nonoperative treatment. Quality of life also improved after treatment (EuroQol 0.76 to 0.89, P = .009). Pain relief was significant, as VAS pain scores decreased from 4.5 to 2.1 (P = .043). All patients with successful nonoperative treatment returned to sports. Seventy-one percent of all athletes were able to return to preparticipation levels, but only 66% of overhead athletes returned to their sport at the same or higher level.

CONCLUSION

Using validated, patient-derived outcome instruments, the present study shows that successful nonoperative treatment of superior labral tears results in improved pain relief and functional outcomes compared with pretreatment assessments. Although 20 patients (51%) in this group elected surgery and may be considered nonoperative treatment failures, those patients with successful nonoperative treatment had significant improvements in pain, function, and quality of life. Return to sports was comparable with patients with successful surgical treatment, although return to overhead sports at the same level was difficult to achieve (66%). Based on these findings, a trial of nonoperative treatment may be considered in patients with the diagnosis of isolated superior labral tear. In overhead athletes and in those patients where pain relief and functional improvement is not achieved, surgical treatment should be considered.

Arthroscopic management of multidirectional instability

The most critical step in successful treatment of shoulder instability does not lie in surgical technique, but in accurate assessment of factors contributing to instability. Multidirectional instability (MDI) is initially treated with rehabilitation. The primary goal of rehabilitation is strengthening of the dynamic stabilizers, including the rotator cuff and scapular stabilizers. There are several surgical techniques described to manage MDI, ranging from the classic Neer inferior capsular shift to a variety of arthroscopic procedures. This article focuses on the arthroscopic management of MDI.

Mineralocorticoid receptor mRNA expression is increased in human hippocampus following brief cerebral ischaemia

BACKGROUND

We have previously reported that neuronal endangerment in vitro and hypothermic transient global ischaemia in vivo each result in increased mineralocorticoid receptor (MR) expression. In both models MR induction is associated with increased neuronal survival, and blocking MR signalling reduces neuronal survival. Furthermore, transgenic overexpression of human MR promotes neuronal survival both in vitro and in vivo.

AIMS

Here we have assessed whether brief periods of cerebral ischaemia in human subjects, such as occurs in cardiac arrest from which successful resuscitation is achieved, are associated with a sustained increase in hippocampal MR mRNA expression.

METHODS

Human post-mortem brain sections from patients who had died in the weeks following cardiac arrest were analysed for MR mRNA expression by in situ hybridization.

RESULTS

Sustained upregulation of MR mRNA expression was observed in the dentate gyrus region of human hippocampus following a brief episode of cerebral ischaemia.

CONCLUSIONS

This confirms that MR mRNA expression is regulated following neuronal injury in human brain, and suggests that the benefits of increased MR expression seen in animal models of ischaemia may also be observed in humans.

Early delayed amputation: a paradigm shift in the limb-salvage time line for patients with major upper-limb injury

Patients with major injuries to the upper limbs sometimes fail to achieve successful limb salvage. During the attempt to fashion a functional limb, multiple painful procedures may be ventured. Despite the best efforts of surgeons and therapists, a nonfunctioning or painful upper limb may remain in place for many months or years before late delayed amputation and progression to productive rehabilitation occur. We present three patient cases that illustrate failed upper-limb salvage. In each case, patients expressed a desire for amputation at 6 months after their injury. To reduce the pain and suffering that patients with failed limb salvage endure, we propose a paradigm shift in the limb-salvage time line. We suggest that patients be evaluated for early delayed amputation 6 months after their injury.

Hemiarthroplasty for the rotator cuff-deficient shoulder

BACKGROUND

Hemiarthroplasty is a common treatment for cuff tear arthropathy and glenohumeral arthritis associated with a massive tear of the rotator cuff; however, to our knowledge, long-term outcomes and preoperative factors affecting results have not been reported.

METHODS

Thirty-four shoulders in thirty-one patients with cuff tear arthropathy or a massive rotator cuff tear with glenohumeral arthritis underwent hemiarthroplasty at an average age of seventy-two years. Outcomes in all patients were evaluated by direct physical examination and according to the limited goals criteria of Neer et al. at a mean of 3.7 years postoperatively. In twenty-five shoulders, long-term outcomes were measured with use of the American Shoulder and Elbow Surgeons (ASES) scoring system and follow-up data were obtained at a mean of ten years (range, four to sixteen years) postoperatively.

RESULTS

Twenty-six of thirty-four shoulders satisfied the limited goals criteria described by Neer et al. The mean active forward elevation improved from 78 degrees preoperatively to 111 degrees postoperatively (p < 0.001). The mean active external rotation improved from 15 degrees preoperatively to 38 degrees postoperatively (p < 0.0001). One patient with a history of four failed rotator cuff repairs had anterosuperior instability develop after surgery. The mean final total ASES score was 67 points (range, 35 to 100 points). Of the sixteen shoulders in patients who could actively elevate the arm to >or=90 degrees preoperatively, fourteen achieved satisfactory results according to the limited goals criteria of Neer et al. Patients who could actively elevate the arm to 90 degrees had significantly better function (mean ASES function score, 31 compared with 23 points; p = 0.05), pain relief (mean ASES pain score, 48 compared with 30 points; p = 0.002), and higher total ASES scores (mean, 80 compared with 54 points; p < 0.001) than the patients who were unable to actively elevate the arm to 90 degrees .

CONCLUSIONS

Hemiarthroplasty can provide good long-term results in rotator cuff-deficient patients with glenohumeral arthritis. Patients who have preoperative forward elevation of >or=90 degrees benefit the most. A low complication rate can be expected for this procedure.

The Neuropathology of HIV/AIDS

The introduction of Highly Active Anti-retroviral Therapy (HAART) has resulted in significant decreases in morbidity and mortality for subjects infected with HIV. The brain is a major target organ for HIV resulting in significant neuropathological changes in most HIV infected subjects and a wide range of clinical neurological symptoms including HIV associated dementia. In the pre-HAART era HIV associated dementia was a common complication of AIDS. However, since the introduction of HAART the incidence of HIV associated dementia has fallen, but the prevelance has actually risen due to the increasing number of infected subjects and increased life expectancy. HIV associated dementia correlates most closely with neuroinflammation rather than directly with viral load or HIV encephalitis. HIV related clinical and neuropathological disorders are more prevalent in drug abusers than in other risk groups. This review focuses on the shifting pathology observed in HIV infected subjects since the introduction of HAART, discussing the clinical manifestations of these and the influence of confounding factors such as drug abuse and Hepatitis C co-infection.

Tissue and organ donation for research in forensic pathology: the MRC Sudden Death Brain and Tissue Bank

Novel methodological approaches to the investigation of brain and non-central nervous system disorders have led to increased demand for well-characterized, high quality human tissue samples, particularly from control cases. In the setting of the new Human Tissue legislation, we sought to determine whether relatives who have been suddenly bereaved are willing to grant authorization for research use of post mortem tissue samples and organs in sufficient numbers to support the establishment of a brain and tissue bank based in the forensic service. Research authorization was sought from families on the day prior to forensic post mortem examination followed up by written confirmation. We have to date selected individuals who have died suddenly (age range 1-89 years) and who were likely to have normal brains or who had displayed symptoms of a CNS disorder of interest to researchers, including psychiatric disorders. One hundred and eleven families have been approached during the first 2 years of this project. Research use of tissue samples was authorized by 96% of families and 17% agreed to whole brain donation. Audit of families' experience does not suggest that they are further distressed by being approached. Respondents expressed a clear view that the opportunity for research donation should be open to all bereaved families. Despite the sometimes long post mortem intervals, the quality of tissue samples is good, as assessed by a range of markers including Agilent BioAnalyzer quantification of RNA integrity (mean value 6.4). We conclude that the vast majority of families are willing to support research use of post mortem tissues even in the context of sudden bereavement and despite previous adverse publicity. The potential for acquisition of normal CNS and non-CNS tissues and of various hard-to-get CNS disorders suggests that efforts to access the forensic post mortem service for research material are eminently worthwhile.

Infective dementias

A wide range of infectious diseases can result in dementia, although the identity and nature of these diseases has changed over time. Two of the most significant current groups in terms of scientific complexity are HIV/AIDS and prion diseases. In these disorders, dementia occurs either as a consequence of targeting the brain and selectively damaging neurones, or by an indirect effect of neuroinflammation. In prion diseases, both direct neurotoxicity and neuroinflammation may act to result in neuronal damage. In HIV encephalitis, the progression of the dementia is slower, perhaps reflecting indirect damage that appears to result from neuroinflammation as a main cause of neuronal death. An ever-increasing range of model systems is now available to study the neuronal damage in infectious dementias, ranging from cell culture systems to animal models, some of which, particularly in the case of prion diseases, are very well characterised and amenable to controlled manipulation in terms of both host and agent parameters. As valuable as these experimental models are, they do not allow a direct approach to an understanding of dementia, the complexities of which cannot readily be studied in vitro or in animal models, but they do allow studies of interventions and therapeutic strategies. This review summarises the current state of knowledge regarding the major infective dementias.

How a neuropsychiatric brain bank should be run: a consensus paper of Brainnet Europe II

The development of new molecular and neurobiological methods, computer-assisted quantification techniques and neurobiological investigation methods which can be applied to the human brain, all have evoked an increased demand for post-mortem tissue in research. Psychiatric disorders are considered to be of neurobiological origin. Thus far, however, the etiology and pathophysiology of schizophrenia, depression and dementias are not well understood at the cellular and molecular level. The following will outline the consensus of the working group for neuropsychiatric brain banking organized in the Brainnet Europe II, on ethical guidelines for brain banking, clinical diagnostic criteria, the minimal clinical data set of retrospectively analyzed cases as well as neuropathological standard investigations to perform stageing for neurodegenerative disorders in brain tissue. We will list regions of interest for assessments in psychiatric disorder, propose a dissection scheme and describe preservation and storage conditions of tissue. These guidelines may be of value for future implementations of additional neuropsychiatric brain banks world-wide.

Dura mater-associated Creutzfeldt-Jakob disease: experience from surveillance in the UK

Between 1970 and 2003, seven cases of human dura mater-associated Creutzfeldt-Jakob disease (CJD) were identified in the UK. Furthermore, we identified a case of CJD in a porcine dura graft recipient. The mean incubation period of the human dura mater cases was 93 (range 45-177) months. The clinico-pathological features of the cases are described and compared with cases previously reported in the world literature.

The Scottish Perinatal Neuropathology Study-clinicopathological correlation in stillbirths

OBJECTIVE

To examine the neuropathology of fetuses dying before birth, to determine the timing of any brain damage seen and to ascertain clinical associations of pre-existing brain damage.

DESIGN

Population-based observational study.

SETTING

All 22 delivery units within Scotland, 1995-1998.

SAMPLE

All stillborn fetuses > or =24 weeks of gestation excluding those with chromosomal abnormality or central nervous system/cardiothoracic malformation.

METHODS

Clinical detail was collected on all stillborn fetuses. Requests for postmortem included separate request for detailed neuropathological examination. Stillborn fetuses were classified as full term antepartum (normal growth/growth restricted), preterm antepartum (normal growth/growth restricted), intrapartum (full term/preterm), multiple births and stillborn fetuses following abruptions. Clinicopathological correlation attempted to define the timing of brain insult. Placentas were examined for each case where available.

MAIN OUTCOME MEASURES

Presence of established and/or recent brain damage. RESULTS Clinical details were available for 471 stillborn fetuses, and detailed neuropathology was possible in 191 cases. Of these 191, 13 were multiple births, 9 died following abruption, 12 were intrapartum deaths and 157 were antepartum stillborn fetuses (99 preterm and 58 full term). Recent or established brain damage was seen in 66% of the entire cohort. Thirty-five percent of all cases showed well-established hypoxic damage predating the last evidence of fetal life, and this was more common in preterm fetuses (P = 0.015), those fetuses with evidence of recent damage (P < 0.001), in pregnancies complicated by pregnancy-induced hypertension (P = 0.044) and those in whom the placenta was <10th centile (P = 0.002).

CONCLUSIONS

Brain damage is commonly seen in stillborn infants, and in around one-third of cases, damage predates the period immediately before death. Factors suggesting suboptimal placental function are associated with such damage. Early identification of placental impairment may lead to improved pregnancy outcome.

An immune control model for viral replication in the CNS during presymptomatic HIV infection

The brain is targeted by human immunodeficiency virus type 1 (HIV-1) during the course of untreated infection, leading to cognitive impairment, neurological damage and HIV encephalitis (HIVE). To study early dynamics of HIV entry into the brain, we examined a unique autopsy series of samples obtained from 15 untreated individuals who died in the presymptomatic stages of infection from non-HIV causes. HIV was detected and quantified by limiting dilution PCR and genetically characterized in the V3 region of env. Limiting dilution was shown to be essential for correct estimation of genetic partitioning between brain- and lymphoid-associated HIV populations. While no actively expressing HIV-infected cells were detected by immunohistochemistry, variable and generally extremely low levels of proviral DNA were detected in presymptomatic brain samples. V3 region sequences were frequently genetically distinct from lymphoid-associated HIV variants, with association index (AI) values similar to those observed in cases of HIVE. Infiltration of CD8 lymphocytes in the brain was strongly associated with expression of activation markers (MHCII; R = 0.619; P < 0.05), the presence of HIV-infected cells (proviral load; R = 0.608; P < 0.05) and genetic segregation of brain variants from populations in lymphoid tissue (AI value, R = -0.528; P approximately 0.05). CD8 lymphocytes may thus limit replication of HIV seeded into the brain in early stages of infection. Neurological complications in AIDS occur when this control breaks down, due to systemic immunosuppression from HIV that destroys CD8 lymphocyte function and/or through the evolution of more aggressive neuropathogenic variants.

Hyperphosphorylated tau and amyloid precursor protein deposition is increased in the brains of young drug abusers

Drug abuse is a major problem worldwide. The incidence of drug-related deaths attributed to opiate abuse is increasing annually. Apart from routine examination, little is known of the neuropathology of drug abuse. We, and others, have shown previously that drug abuse is associated with microglial activation. We hypothesised that neuroinflammation might lead to premature neurodegeneration in drug abusers. We investigated the brains of young opiate abusers (n=34, all<40 years) for the presence of proteins associated with neurodegenerative diseases and compared them with the brains of age-matched, non-drug users (n=16) all of whom died suddenly. Detailed immunohistochemical analysis of the hippocampus, brainstem and basal ganglia for hyperphosphorylated tau, beta-amyloid, beta-amyloid precursor protein (betaAPP) and ubiquitin demonstrated an excess of AT 8-positive neurofibrillary tangles (NFT) in the drug abusers. These were not only more prevalent in the drug abusers than in controls (44%vs. 19%) but also involved more brain areas. In controls NFT were confined to the entorhinal cortex whereas in drug users they were also found in the subiculum, temporal neocortex, nucleus basalis of Meynert and the locus coeruleus. Virtually no amyloid plaques were present but betaAPP positivity was again much more common in drug abusers than controls (73%vs. 20% in the brainstem and 59%vs. 23% in the temporal lobe). There is no suggestion that these drug abusers had displayed major cognitive impairment although detailed neuropsychological assessment is difficult in this subject group. Likely causes of hyperphosphorylated tau deposition in drug abuse include hypoxic-ischaemic injury, microglial-associated cytokine release and possibly drug-associated neurotoxicity or hepatitis. Head injury, which is another major risk factor, does not appear to have contributed to our findings. Genetic factors also merit consideration. It is unclear at present how much of the hyperphosphorylated tau detected in these young drug abusers represents a transitory phenomenon.

Third ventricular chordoid glioma: clinicopathological study of two cases with evidence for a poor clinical outcome despite low grade histological features

Chordoid glioma of the third ventricle is a rare glial tumour whose precise histogenesis remains uncertain. We describe two cases that presented recently to our department and review the background literature. The neoplasm tends to occur in women and its clinical presentation is variable, resulting from acute hydrocephalus or impingement upon local structures. However, the radiological appearance is distinct, with an ovoid shape, hyperdensity and uniform contrast enhancement on computerized tomography and magnetic resonance imaging. Intraoperative smear diagnosis is difficult because of the lack of specific features, although the presence of metachromatic extracellular mucin may be useful. The characteristic histological appearance is that of cords and clusters of cohesive, oval-to-polygonal epithelioid cells with abundant eosinophilic cytoplasm and a mucinous background. There is often a mixed chronic inflammatory infiltrate with lymphocytes and plasma cells with Russell bodies. The main differentials for histological diagnosis include chordoid meningiomas, pilocytic astrocytomas and ependymomas. An immunohistochemical panel including antibodies to glial fibrillary acidic protein, CD 34, epithelial membrane antigen, pan cytokeratin, S100 and vimentin can be used to distinguish between these possibilities. Ultrastructurally the tumour cells have basal lamina and microvilli, reminiscent of ependymomas. The clinical outcome in our cases was poor because of the location of the lesion and its close relation to the hypothalamus. Limited follow-up after surgery with or without radiotherapy suggests that as-full-as-possible resection favours a better outcome, although surgery in this area carries significant operative risks.

Evidence of a breakdown of corticostriatal connections in Parkinson's disease

Dendritic spines are important structures which receive synaptic inputs in many regions of the CNS. The goal of this study was to test the hypothesis that numbers of dendritic spines are significantly reduced on spiny neurones in basal ganglia regions in Parkinson's disease as we had shown them to be in a rat model of the disease [Exp Brain Res 93 (1993) 17]. Postmortem tissue from the caudate and putamen of patients suffering from Parkinson's disease was compared with that from people of a similar age who had no neurological damage. The morphology of Golgi-impregnated projection neurones (medium-sized spiny neurones) was examined quantitatively. The numerical density of dendritic spines on dendrites was reduced by about 27% in both nuclei. The size of the dendritic trees of these neurones was also significantly reduced in the caudate nucleus from the brains of PD cases and their complexity was changed in both the caudate nucleus and the putamen. Dendritic spines receive crucial excitatory input from the cerebral cortex. Reduction in both the density of spines and the total length of the remaining dendrites is likely to have a grave impact on the ability of these neurones to function normally and may partly explain the symptoms of the disorder.

Influence of HAART on HIV-related CNS disease and neuroinflammation

Neuroinflammation has an established link with AIDS-related dementia but has not been investigated in the post-highly active anti-retroviral therapy (HAART) era. In this autopsy study we examined post-HAART cases in Edinburgh for the presence of HIV-related pathology and in well-treated cases for evidence of neuroinflammation. We focused on basal ganglia and the hippocampus, 2 key areas of the brain for cognitive functioning and compared pre- and post-HAART cases for neuroinflammatory status. We find evidence, post-HAART, that there is a high level of microglial/macrophage activation that is comparable with the levels seen, pre-HAART, in HIV encephalitis (HIVE) and AIDS cases. This result was maximal in the hippocampus where microglial/macrophage upregulation in the HAART-treated group exceeded that seen in HIVE. In the basal ganglia, HAART-treated cases showed significantly higher levels of CD68-positive microglia/macrophages than in control brains (p = 0.004), and in the hippocampus levels were significantly higher than those seen in control cases, pre-HAART AIDS, and presymptomatic brains (p = 0.01). However, lymphocyte levels in the areas examined were low in HAART-treated cases. We conclude that there is a surprising degree of ongoing neuroinflammation in HAART-treated patients, particularly in the hippocampus. This may pose a threat for the future health of individuals maintained long-term on HAART therapy.

Does drug abuse alter microglial phenotype and cell turnover in the context of advancing HIV infection?

The aim of this study was to test the effects of drug abuse, in particular opiate abuse, on the phenotype and turnover of microglial cells within the brain in the context of advancing HIV infection. Basal ganglia and hippocampus sections were studied in 51 cases divided into six groups: HIV-negative normal controls, HIV-negative drug abusers, AIDS nondrug abusers, AIDS drug abusers, HIV encephalitis (HIVE) nondrug abusers and HIVE drug abusers. None of the cases studied had received highly active anti-retroviral therapy (HAART). Microglial phenotypes were defined using CD14, CD16, CD68 and major histocompatibility class II (MHC II). Microglial turnover was assessed using terminal deoxynucleotidyl transferase mediated dUTP nick end labelling (TUNEL) (DNA damage), BAX (proapoptotic marker), Fas (CD95) (proapoptotic), proliferating cell nuclear antigen (PCNA) (proliferation and DNA repair), Ki-67 (cell proliferation) and BCL-2 (antiapoptosis). We find increased expression of MHC II and CD16 in response to drug abuse. We also noted increased levels of TUNEL positivity in drug abusers compared to nondrug abusers, although conversely we found lower levels of BAX in those who had abused drugs. We find no evidence of microglial proliferation in any of our study groups, including HIVE, although HIV infection leads to increased expression of CD16, CD68 and MHC II. CD14 expression was restricted to perivascular microglia in all groups (including normal controls) apart from the two HIVE groups where some but not all cases also showed parenchymal expression of CD14. In contrast, CD16 was found in parenchymal microglia in all groups. Using high-pressure antigen retrieval and tyramide signal amplification, we find moderately high levels of CD16 expression in the parenchyma of normal brains which is not normally observed using standard avidin/biotin complex (ABC) techniques. This suggests that a low basal expression of CD16 occurs in many resident microglial cells which may potentially be upregulated in HIV-infected individuals. From these data, we suggest that not all the CD16+ parenchymal cells detected in AIDS brains (using ABC) represent influx of monocyte lineage cells from the blood. Finally the increased expression of MHC II and CD68 detected in drug abusers with HIVE compared to nondrug abusers with HIVE suggests that the combination of drug abuse and HIV infection has a greater deleterious effect on the brain than either individual insult on its own.

Distribution of apolipoprotein E alleles in a Scottish healthy newborn population

The different alleles of the human apolipoprotein E polymorphism, ApoE epsilon2, epsilon3, epsilon4, have important implications for systemic lipid metabolism, immunological function and for the brain in maintenance and in response to injury. Few studies have focussed on their role in early life. The ApoE alleles and genotypes were ascertained in the cord blood of 371 full-term and normal Scottish newborn infants using PCR methodology. The results were compared to previously published data for Scottish adults in late middle age. There was a marginally significant over-representation of epsilon4 and under-representation of epsilon3 alleles in healthy infants as compared with adults. Inspection of the individual genotypes confirms the over-representation of ApoE 4/4 and 2/4 with a reduction in ApoE 2/3 and 3/3 when compared with Scottish adults. Although these results may have occurred by chance, the ApoE epsilon4 allele may confer an increased risk of premature death.

Brain damage and axonal injury in a Scottish cohort of neonatal deaths

Despite the clinical and medicolegal significance attached to perinatal asphyxia, the neuropathological basis of this condition remains obscure. There are very few studies in the literature which correlate the pathological findings in neonatal brains with detailed epidemiological data, and none which are population based. In a Scotland-wide study of neonatal deaths, 70 brains have been examined. On the basis of glial and macrophage reactions, we previously identified infants with putative antepartum brain damage in this cohort and have related these reactions to signs of birth asphyxia. The present study explores the extent of neuronal/axonal injury in these infants since this is likely to be the basis for neurological deficits in surviving infants. We have also investigated these brains for beta-amyloid precursor protein (betaAPP) positivity to determine whether this is a useful marker of neuronal injury in neonates. Neuronal eosinophilia and karyorrhexes were detected in 43% and 27% of the cohort, respectively; maximally in the subiculum and ventral pons, but often present elsewhere. White matter damage was detected in 24% of cases but without classic cystic lesions of periventricular leucomalacia. betaAPP positivity was present in neuronal soma in 52% of cases and, in axons, in 27% of cases, and was seen from as early as 25-weeks gestation. Axonal bulbs were clearly delineated by betaAPP positivity and were usually located in the cerebral white matter and internal capsule, and infrequently in the brain stem. Although white matter damage and betaAPP axonal positivity were often detected in the same cases (P = 0.034), these features also occurred independently of each other. Both neuronal karyorrhexes and white matter betaAPP positivity were significantly correlated with the features of birth asphyxia, particularly a history of seizures. Immunocytochemistry for both betaAPP and glial fibrillary acidic protein proved useful in detecting neuropathological features which escaped detection on routine examination, particularly in preterm infants. The presence together of recent and older damage in individual brains suggests that there is an ongoing neuronal response to cerebral insults. We find that betaAPP is a useful marker of white matter damage in the neonatal brain. Immunopositivity for betaAPP in these circumstances is not attributable to inflicted or accidental trauma. While birth-related trauma cannot be ruled out, hypoxia/ischaemia is a likely cause in these infants. However, the exact pathogenesis of neuronal/axonal injury in the neonatal brain remains unclear.

An update on the neuropathology of HIV in the HAART era

This review compares the neuropathology of highly active antiretroviral therapy (HAART)-treated HIV+ individuals with the reported central nervous system (CNS) findings from the pre-HAART era. HAART has had considerable success in combating HIV-related immune collapse and has prevented many of the former end-stage complications of AIDS. However, with increased survival times the prevalence of minor HIV-associated cognitive impairment appears to be rising among treated patients and this may be a particular risk for older individuals. HIV encephalitis (HIVE) is still prevalent in treated patients although attenuated forms of HIVE and CNS opportunistic disorders are also observed. Some subjects show very significant CNS lymphocytic infiltrates in the context of HAART-induced immune reconstitution. HIV-associated cognitive impairment correlates best with the increased presence of activated, though not necessarily infected, microglia and CNS macrophages. This suggests that indirect mechanisms of neuronal injury and loss occur in HIV/AIDS as a basis for dementia since neurones are not themselves productively infected. Research to elucidate the mechanisms of neuronal injury in HIV/AIDS may contribute to the understanding of CNS function not only in HAART-treated subjects but also in other neurodegenerative disorders.

The Scottish perinatal neuropathology study: clinicopathological correlation in early neonatal deaths

BACKGROUND

A proportion of neonatal deaths from asphyxia have been shown to be associated with pre-existing brain injury.

OBJECTIVES

(a) To compare the epidemiology of infants displaying signs of birth asphyxia with those not showing signs; (b) to examine the neuropathology and determine if possible the timing of brain insult comparing asphyxiated with non-asphyxiated infants; (c) to compare the clinical features of those born with birth asphyxia with and without pre-labour damage.

METHODS

Over a two year period, all 22 Scottish delivery units collected clinical details on early neonatal deaths. Requests for post mortem included separate requests for detailed neuropathological examination of the brain. Infants were classified into two groups: birth asphyxia and non-birth asphyxia. Clinicopathological correlation was used to attempt to define the time of brain insult.

RESULTS

Detailed clinical data were available on 137 of 174 early neonatal deaths that met the inclusion criteria. Seventy of 88 parents who had agreed to post mortem examination consented to a detailed examination of additional samples from the brain; in 53 of these cases the infant was born in an asphyxiated condition. All asphyxiated and encephalopathic infants, 38% of mature and 52% of preterm infants with features of birth asphyxia but without encephalopathy, and only one of 12 infants without any signs of birth asphyxia showed damage consistent with onset before the start of labour.

CONCLUSIONS

In a large proportion of neonatal deaths, brain injury predates the onset of labour. This is more common in infants born in an asphyxiated condition.