Clinical Outcome following Management of Severe Osteomyelitis due to Pin Site Infection.

Aim: This study has investigated cases of pin site infection (PSI) which required surgery for persistent osteomyelitis (OM) despite pin removal. Materials and methods: Patients requiring surgery for OM after PSI between 2011 and 2021 were included in this retrospective cohort study. Single-stage surgery was performed in accordance with a protocol at one institution. This involved deep sampling, debridement, implantation of local antibiotics, culture-specific systemic antibiotics and soft tissue closure. A successful outcome was defined as an infection-free interval of at least 24 months following surgery. Results: Twenty-seven patients were identified (the sites were 22 tibias, 2 humeri, 2 calcanei, 1 radius); about 85% of them were males with a median age of 53.9 years. The majority of infections (21/27) followed fracture treatment. Fifteen patients were classified as BACH uncomplicated and 12 were BACH complex. Staphylococci were the most common pathogens, polymicrobial infections were detected in five cases (19%). Seven patients required flap coverage which was performed in the same operation.After a median of 3.99 years (2.00-8.05) follow-up, all patients remained infection free at the site of the former OM. Wound leakage after local antibiotic treatment was seen in 3/27 (11.1%) cases but did not require further treatment. Conclusion: Osteomyelitis after PSI is uncommon but has major implications for the patient as 7 patients needed flap coverage. This reinforces the need for careful pin placement and pin site care to prevent deep infection. These infections were treated in accordance with a protocol and were not managed simply by curettage. All patients treated in this manner remained infection-free after a minimum follow-up of 2 years suggesting that this protocol is effective. Clinical significance: Pin site infection is a very common complication in external fixation. The sequela of a chronic pin site OM is rare but the implications to the patient are huge. In this series, more than a quarter of patients required flap coverage as part of the treatment of the deep infection. How to cite this article: Frank FA, Pomeroy E, Hotchen AJ, et al. Clinical Outcome following Management of Severe Osteomyelitis due to Pin Site Infection. Strategies Trauma Limb Reconstr 2024;19(1):21-25.

A practical definition of pin site infection.

Pin Site Infection (PSI) is the most common complication of external fixation treatment. Several classifications and diagnostic approaches have been used with reported incidences varying widely from 1 to 100 %. The quality of the existing literature is limited by the absence of a definition. This renders comparing literature and developing evidence-based algorithms for prevention, diagnostics, and treatment difficult to impossible. Similar problems were identified with prosthetic joint infection (PJI) and fracture-related infection (FRI) in recent years, resulting in new, validated definitions. PSI is complicated by the complexity of the issue. Numerous factors in PSI need consideration. Factors may be related to the patient, the surgical technique, the pin-bone interface, the pin-skin interface, the choice of external fixation device and/or the material used and its properties. Reliably diagnosing PSI is one of the most pressing issues. New definitions for FRI or PJI have diagnostic criteria which can be either confirmatory or suggestive. Any positive finding of a confirmatory criterion constitutes an infection. Although PSI resembles PJI and FRI, distinct differences are present. The skin is never closed, and bacterial colonization is inevitable along the treatment duration. The external fixator is only temporarily in place; thus, the goal of all measures is to continue the external fixator until the intended indication is reached. This paper proposes the principles of a definition of PSI. This definition is not designed to guide any treatment of PSI. Its purpose is to create common ground for clinical investigations and publishing further research.

A comparison of clinical and radiological outcomes between two different biodegradable local antibiotic carriers used in the single-stage surgical management of long bone osteomyelitis.

Aims: Dead-space management, following dead bone resection, is an important element of successful chronic osteomyelitis treatment. This study compared two different biodegradable antibiotic carriers used for dead-space management, and reviewed clinical and radiological outcomes. All cases underwent single-stage surgery and had a minimum one-year follow-up. Methods: A total of 179 patients received preformed calcium sulphate pellets containing 4% tobramycin (Group OT), and 180 patients had an injectable calcium sulphate/nanocrystalline hydroxyapatite ceramic containing gentamicin (Group CG). Outcome measures were infection recurrence, wound leakage, and subsequent fracture involving the treated segment. Bone-void filling was assessed radiologically at a minimum of six months post-surgery. Results: The median follow-up was 4.6 years (interquartile range (IQR) 3.2 to 5.4; range 1.3 to 10.5) in Group OT compared to 4.9 years (IQR 2.1 to 6.0; range 1.0 to 8.3) in Group CG. The groups had similar defect sizes following excision (both mean 10.9 cm3 (1 to 30)). Infection recurrence was higher in Group OT (20/179 (11.2%) vs 8/180 (4.4%), p = 0.019) than Group CG, as was early wound leakage (33/179 (18.4%) vs 18/180 (10.0%), p = 0.024) and subsequent fracture (11/179 (6.1%) vs 1.7% (3/180), p = 0.032). Group OT cases had an odds ratio 2.9-times higher of developing any one of these complications, compared to Group CG (95% confidence interval 1.74 to 4.81, p < 0.001). The mean bone-void healing in Group CG was better than in Group OT, in those with ≥ six-month radiological follow-up (73.9% vs 40.0%, p < 0.001). Conclusion: Local antibiotic carrier choice affects outcome in chronic osteomyelitis surgery. A biphasic injectable carrier with a slower dissolution time was associated with better radiological and clinical outcomes compared to a preformed calcium sulphate pellet carrier.

An elephant in the glasshouse? Trade-offs between acceleration and transformation in COVID-19 vaccine innovation policies.

Against the backdrop of a failing vaccine innovation system, innovation policy aimed at creating a COVID-19 vaccine was surprisingly fast and effective. This paper analyzes the influence of the COVID-19 landscape shock and corresponding innovation policy responses on the existing vaccine innovation system. We use document analysis and expert interviews, performed during vaccine development. We find that the sharing of responsibility between public and private actors on various geographical levels, and the focus on accelerating changes in the innovation system were instrumental in achieving fast results. Simultaneously, the acceleration exacerbated existing societal innovation barriers, such as vaccine hesitancy, health inequity, and contested privatization of earnings. Going forward, these innovation barriers may limit the legitimacy of the vaccine innovation system and reduce pandemic preparedness. Next to a focus on acceleration, transformative innovation policies for achieving sustainable pandemic preparedness are still urgently needed. Implications for mission-oriented innovation policy are discussed.

Mid- to long-term results of single-stage surgery for patients with chronic osteomyelitis using a bioabsorbable gentamicin-loaded ceramic carrier.

AIMS: Excision of chronic osteomyelitic bone creates a dead space which must be managed to avoid early recurrence of infection. Systemic antibiotics cannot penetrate this space in high concentrations, so local treatment has become an attractive adjunct to surgery. The aim of this study was to present the mid- to long-term results of local treatment with gentamicin in a bioabsorbable ceramic carrier. METHODS: A prospective series of 100 patients with Cierny-Mader Types III and IV chronic ostemyelitis, affecting 105 bones, were treated with a single-stage procedure including debridement, deep tissue sampling, local and systemic antibiotics, stabilization, and immediate skin closure. Chronic osteomyelitis was confirmed using strict diagnostic criteria. The mean follow-up was 6.05 years (4.2 to 8.4). RESULTS: At final follow-up, six patients (six bones) had recurrent infection; thus 94% were infection-free. Three infections recurred in the first year, two in the second year, and one 4.5 years postoperatively. Recurrence was not significantly related to the physiological class of the patient (1/20 Class A (5%) vs 5/80 Class B (6.25%); p = 0.833), nor was it significantly related to the aetiology of the infection, the organisms which were cultured or the presence of nonunion before surgery (1/10 with nonunion (10%) vs 5/90 without nonunion (5.6%); p = 0.570). Organisms with intermediate or high-grade resistance to gentamicin were significantly more likely in polymicrobial infections (9/21; 42.8%) compared with monobacterial osteomyelitis (7/79 (8.9%); p < 0.001). However, recurrence was not significantly more frequent when a resistant organism was present (1/16 for resistant cases (6.25%) vs 5/84 in those with a microbiologically sensitive infection (5.95%); p = 0.958). CONCLUSION: We found that a single-stage protocol, including the use of a high-delivery local antibiotic ceramic carrier, was effective over a period of several years. The method can be used in a wide range of patients, including those with significant comorbidities and an infected nonunion.Cite this article: Bone Joint J 2022;104-B(9):1095-1100.

SARS-CoV-2 suppresses mRNA expression of selenoproteins associated with ferroptosis, endoplasmic reticulum stress and DNA synthesis.

Higher selenium status has been shown to improve the clinical outcome of infections caused by a range of evolutionally diverse viruses, including SARS-CoV-2. However, the impact of SARS-CoV-2 on host-cell selenoproteins remains elusive. The present study investigated the influence of SARS-CoV-2 on expression of selenoprotein mRNAs in Vero cells. SARS-CoV-2 triggered an inflammatory response as evidenced by increased IL-6 expression. Of the 25 selenoproteins, SARS-CoV-2 significantly suppressed mRNA expression of ferroptosis-associated GPX4, DNA synthesis-related TXNRD3 and endoplasmic reticulum-resident SELENOF, SELENOK, SELENOM and SELENOS. Computational analysis has predicted an antisense interaction between SARS-CoV-2 and TXNRD3 mRNA, which is translated with high efficiency in the lung. Here, we confirmed the predicted SARS-CoV-2/TXNRD3 antisense interaction in vitro using DNA oligonucleotides, providing a plausible mechanism for the observed mRNA knockdown. Inhibition of TXNRD decreases DNA synthesis which is thereby likely to increase the ribonucleotide pool for RNA synthesis and, accordingly, RNA virus production. The present findings provide evidence for a direct inhibitory effect of SARS-CoV-2 replication on the expression of a specific set of selenoprotein mRNAs, which merits further investigation in the light of established evidence for correlations between dietary selenium status and the outcome of SARS-CoV-2 infection.

Clostridium cadaveris Osteomyelitis: an Unusual Pathogen which Highlights the Importance of Deep Tissue Sampling in Chronic Osteomyelitis.

Clostridium cadaveris, named following its identification in human corpses, is an unusual pathogen. We report the first case of C. cadaveris osteomyelitis. This case highlights the importance of deep tissue sampling and appropriate culture to correctly identify causative pathogens and guide targeted antimicrobial therapy in difficult-to-treat infections like chronic osteomyelitis.

Comparison of Ilizarov Bifocal, Acute Shortening and Relengthening with Bone Transport in the Treatment of Infected, Segmental Defects of the Tibia.

This prospective study compared bifocal acute shortening and relengthening (ASR) with bone transport (BT) in a consecutive series of complex tibial infected non-unions and osteomyelitis, for the reconstruction of segmental defects created at the surgical resection of the infection. Patients with an infected tibial segmental defect (>2 cm) were eligible for inclusion. Patients were allocated to ASR or BT, using a standardized protocol, depending on defect size, the condition of soft tissues and the state of the fibula (intact or divided). We recorded the Weber-Cech classification, previous operations, external fixation time, external fixation index (EFI), follow-up duration, time to union, ASAMI bone and functional scores and complications. A total of 47 patients (ASR: 20 patients, BT: 27 patients) with a median follow-up of 37.9 months (range 16-128) were included. In the ASR group, the mean bone defect size measured 4.0 cm, and the mean frame time was 8.8 months. In the BT group, the mean bone defect size measured 5.9cm, and the mean frame time was 10.3 months. There was no statistically significant difference in the EFI between ASR and BT (2.0 and 1.8 months/cm, respectively) (p = 0.223). A total of 3/20 patients of the ASR and 15/27 of the BT group needed further unplanned surgery during Ilizarov treatment (p = 0.006). Docking site surgery was significantly more frequent in BT; 66.7%, versus ASL; 5.0% (p < 0.0001). The infection eradication rate was 100% in both groups at final follow-up. Final ASAMI functional rating scores and bone scores were similar in both groups. Segmental resection with the Ilizarov method is effective and safe for reconstruction of infected tibial defects, allowing the eradication of infection and high union rates. However, BT demonstrated a higher rate of unplanned surgeries, especially docking site revisions. Acute shortening and relengthening does not reduce the fixator index. Both techniques deliver good functional outcome after completion of treatment.

Simultaneous debridement, Ilizarov reconstruction and free muscle flaps in the management of complex tibial infection.

Chronic bone infections often present with complex bone and soft tissue loss. Management is difficult and commonly delivered in multiple stages over many months. This study investigated the feasibility and clinical outcomes of reconstruction in one stage. Fifty-seven consecutive patients with chronic osteomyelitis ( n = 27 ) or infected non-union ( n = 30 ) were treated with simultaneous debridement, Ilizarov method and free muscle flap transfer. 41 patients (71.9 %) had systemic co-morbidities (Cierny-Mader group Bs hosts). Infection was confirmed with strict criteria. 48 patients (84.2 %) had segmental defects. The primary outcome was eradication of infection at final follow-up. Secondary outcomes included bone union, flap survival and complications or re-operation related to the reconstruction. Infection was eradicated in 55 / 57 cases (96.5 %) at a mean follow-up of 36 months (range 12-146). No flap failures occurred during distraction but 6 required early anastomotic revision and 3 were not salvageable (flap failure rate 5.3 %). Bony union was achieved in 52 / 57 (91.2 %) with the initial surgery alone. After treatment of the five un-united docking sites, all cases achieved bony union at final follow-up. Simultaneous reconstruction with Ilizarov method and free tissue transfer is safe but requires careful planning and logistic considerations. The outcomes from this study are equivalent or better than those reported after staged surgery.

Sonication versus Tissue Sampling for Diagnosis of Prosthetic Joint and Other Orthopedic Device-Related Infections.

Current guidelines recommend collection of multiple tissue samples for diagnosis of prosthetic joint infections (PJI). Sonication of explanted devices has been proposed as a potentially simpler alternative; however, reported microbiological yield varies. We evaluated sonication for diagnosis of PJI and other orthopedic device-related infections (DRI) at the Oxford Bone Infection Unit between October 2012 and August 2016. We compared the performance of paired tissue and sonication cultures against a "gold standard" of published clinical and composite clinical and microbiological definitions of infection. We analyzed explanted devices and a median of five tissue specimens from 505 procedures. Among clinically infected cases the sensitivity of tissue and sonication culture was 69% (95% confidence interval, 63 to 75) and 57% (50 to 63), respectively (P < 0.0001). Tissue culture was more sensitive than sonication for both PJI and other DRI, irrespective of the infection definition used. Tissue culture yield was higher for all subgroups except less virulent infections, among which tissue and sonication culture yield were similar. The combined sensitivity of tissue and sonication culture was 76% (70 to 81) and increased with the number of tissue specimens obtained. Tissue culture specificity was 97% (94 to 99), compared with 94% (90 to 97) for sonication (P = 0.052) and 93% (89 to 96) for the two methods combined. Tissue culture is more sensitive and may be more specific than sonication for diagnosis of orthopedic DRI in our setting. Variable methodology and case mix may explain reported differences between centers in the relative yield of tissue and sonication culture. Culture yield was highest for both methods combined.

Osteomyelitis of the Pelvic Bones: A Multidisciplinary Approach to Treatment.

Background and Purpose: A case series review of chronic pelvic osteomyelitis treated with combined medical and surgical treatment by a multidisciplinary team. Methods: All patients treated with surgical excision of pelvic osteomyelitis at our tertiary referral centre between 2002 and 2014 were included. All received combined care from a clinical microbiologist, an orthopaedic surgeon and a plastic surgeon. The rate of recurrent infection, wound healing problems and post-operative mortality was determined in all. Treatment failure was defined as reoperation involving further bone debridement, a requirement for the use of long-term suppressive antibiotics or sinus recurrence. Results: Sixty-one adults (mean age 50.2 years, range 16.8-80.6) underwent surgery. According to the Cierny-Mader classification of osteomyelitis there were 19 type II, 35 type III and 7 type IV cases. The ischium was the most common site of infection. Osteomyelitis was usually the result of contiguous focus infection associated with decubitus ulcers, predominantly in patients with spinal or cerebral disorders. Most patients with positive microbiology had polymicrobial infection (52.5%). Thirty patients required soft tissue reconstruction with muscle or myocutaneous flaps. Twelve deaths occurred a mean of 2.8 years following surgery (range 7 days-7.4 years). Excluding these deaths the mean follow-up was 4.6 years (range 1.5-12.2 years). Recurrent infection occurred in seven (11.5%) a mean of 1.5 years post-operatively (92 days - 5.3 years). After further treatment 58 cases (95.1%) were infection free at final follow-up. Interpretation: Patients in this series have many comorbidities and risk factors for poor surgical outcome. Nevertheless, the multidisciplinary approach allows successful treatment in the majority of cases.

Ilizarov Treatment Protocols in the Management of Infected Nonunion of the Tibia.

OBJECTIVES: We present a treatment algorithm comprising 4 Ilizarov methods in managing infected tibial nonunion, using nonunion mobility and segmental defect size to govern treatment choice. DESIGN: Decision protocol analysis study. SETTING: A university-affiliated teaching hospital. PATIENTS/PARTICIPANTS: Seventy-nine patients were treated with 1 of 4 Ilizarov protocols. All patients had undergone at least one previous operation, 38 had associated limb deformity, and 49 had nonviable nonunions. Twenty-six had a new muscle flap at the time of Ilizarov surgery, and 25 had preexisting flaps reused. INTERVENTION: Twenty-six cases were treated with monofocal distraction, 19 with monofocal compression, 16 with bifocal compression/distraction, and 18 with bone transport. MAIN OUTCOME MEASUREMENTS: The primary outcome measure was the absence of recurrent infection. Secondary outcomes included bone union, complications, the Association for the Advancement of Methods of Ilizarov (ASAMI) bone and functional classification scores, and any need for further unplanned surgery. RESULTS: Infection was eradicated in 76 cases (96.2%) with a mean follow-up duration of 40.8 months (range 6-131). All 3 infection recurrences occurred in the monofocal compression group. Following the initial Ilizarov method alone, union was achieved in 68 cases (86.1%) and was highest among the monofocal distraction (96.2%) and bifocal compression/distraction groups (93.8%). Monofocal compression achieved the lowest union rate (73.7%), significantly lower ASAMI scores, and a refracture rate of 31.6%. Bone transport secured union in 77.8% with a 44.4% unplanned reoperation rate. However, infection-free union was 100% after further treatment. CONCLUSIONS: Monofocal compression is not recommended for treating infected, mobile nonunions. Distraction (monofocal or bifocal) was effective and achieved higher rates of union and infection clearance. LEVEL OF EVIDENCE: Level III.

Oral versus intravenous antibiotic treatment for bone and joint infections (OVIVA): study protocol for a randomised controlled trial.

BACKGROUND: Bone and joint infection in adults arises most commonly as a complication of joint replacement surgery, fracture fixation and diabetic foot infection. The associated morbidity can be devastating to patients and costs the National Health Service an estimated £20,000 to £40,000 per patient. Current standard of care in most UK centres includes a prolonged course (4-6 weeks) of intravenous antibiotics supported, if available, by an outpatient parenteral antibiotic therapy service. Intravenous therapy carries with it substantial risks and inconvenience to patients, and the antibiotic-related costs are approximately ten times that of oral therapy. Despite this, there is no evidence to suggest that oral therapy results in inferior outcomes. We hypothesise that, by selecting oral agents with high bioavailability, good tissue penetration and activity against the known or likely pathogens, key outcomes in patients managed primarily with oral therapy are non-inferior to those in patients treated by intravenous therapy. METHODS: The OVIVA trial is a parallel group, randomised (1:1), un-blinded, non-inferiority trial conducted in thirty hospitals across the UK. Eligible participants are adults (>18 years) with a clinical syndrome consistent with a bone, joint or metalware-associated infection who have received ≤7 days of intravenous antibiotic therapy from the date of definitive surgery (or the start of planned curative therapy in patients treated without surgical intervention). Participants are randomised to receive either oral or intravenous antibiotics, selected by a specialist infection physician, for the first 6 weeks of therapy. The primary outcome measure is definite treatment failure within one year of randomisation, as assessed by a blinded endpoint committee, according to pre-defined microbiological, histological and clinical criteria. Enrolling 1,050 subjects will provide 90 % power to demonstrate non-inferiority, defined as less than 7.5 % absolute increase in treatment failure rate in patients randomised to oral therapy as compared to intravenous therapy (one-sided alpha of 0.05). DISCUSSION: If our results demonstrate non-inferiority of orally administered antibiotic therapy, this trial is likely to facilitate a dramatically improved patient experience and alleviate a substantial financial burden on healthcare services. TRIAL REGISTRATION: ISRCTN91566927 - 14/02/2013.

Snow-shoveling and the risk of acute coronary syndromes.

BACKGROUND: Snow-shoveling is a necessary activity for those living in temperate climates, but there are no large studies identifying a connection between this activity and the development of acute coronary syndromes (ACS). OBJECTIVES: The aim of this study was to identify potential factors that place individuals at higher risk for developing a snow-shoveling-related ACS. METHODS: We performed a chart review over two consecutive winter seasons to identify a sample of ACS events associated with shoveling snow. Demographics, cardiovascular risk factors and medication use of the shoveling-related and non-shoveling-related event groups were compared, and multivariate regression was used to identify a subset of relevant factors. RESULTS: Our study population included 500 patients with ACS, mean age of 65.7 ± 13.4 years (range 31-94) and 66.7% of the events occurred in males. A total of 35 (7%) events were documented to have occurred following snow-shoveling. Between patients with snow-shoveling-related and non-related events there were no significant differences in the prevalence of diabetes, hypertension, hypercholesterolemia or sleep apnea. Logistic regression did not show any significant group differences in age and known coronary artery disease; however, those suffering a snow-shoveling-related event were 3.6 times more likely to have a family history of premature cardiovascular disease (p = 0.001) and were 4.8 times more likely to be male (p = 0.01). CONCLUSION: A family history of premature cardiovascular disease and male gender were found to have strong, independent associations with having a snow-shoveling-related ACS. A history of chronic stable angina trended toward an association.

Modular endoprosthetic replacement for failed internal fixation of the proximal femur following trauma.

PURPOSE: Although originally designed for reconstruction after primary malignant bone tumour resection, modular endoprosthetic replacement (EPR) can be used in salvage surgery for complex periprosthetic fracture and failed internal fixation. The purpose of this study was to assess the functional outcome following EPR for failed internal fixation of the proximal femur. METHODS: We assessed clinical and functional outcomes of using a modular tumour endoprosthesis to reconstruct the proximal femur following failed internal fixation in eight consecutive patients between 2001 and 2008. RESULTS: There were four men and four women, with a mean age of 67.5 (range 50-79) years and a mean follow-up of 16.5 (6-36) months. All patients had failed internal fixation for traumatic proximal femoral fractures--four 31.A2.3, two 31.A3.1, two 31.A3.3 using the Arbeitsgemeinshaft für Osteosynthesefragen (AO) fracture classification. Mean time from the first attempted internal fixation to definitive EPR was 34 (6-102) months, and the median number of previous surgical procedures was two (1-11). Histology revealed infection (two cases), uninfected nonunion (five cases) and plasmocytoma (one case). The EPR was carried out as a one-stage procedure in six cases and a two-stage procedure in two cases. Mean postoperative Harris Hip Score was 71.4 (range 64-85). There were no surgical complications. One patient died as a result of systemic complications of myeloma several years following EPR. CONCLUSIONS: EPR is an effective salvage procedure for failed fixation of traumatic proximal femoral fractures. Immediate weightbearing and a good functional outcome can be expected in this difficult group of patients.

Ilizarov for radiologists.

If you had a choice, you would probably not wish to undergo Ilizarov treatment; it is a long and stressful treatment and requires considerable effort. If you have a major deformity, massive bone loss or complex bone infection, however, the other options are even less appealing. Large allografts have high rates of infection, non-union and late fracture, and metal implants are at risk of loosening and fatigue particularly in younger patients. Sometimes the only other option is an amputation. The Ilizarov method offers the ability to correct deformity and grow new, normal bone which will continue to serve its purpose for the rest of your life.

Profiling schoolchildren in pain and associated demographic and behavioural factors: a latent class approach.

Musculoskeletal pain in adolescence is common and individuals frequently report pain in different sites. However, statistical analysis is often limited to considering one or a few pain sites. In this study latent class analysis was used to classify individuals into latent classes in terms of their patterns of endorsing ten musculoskeletal sites. Previously established covariates of musculoskeletal pain in adolescents were then assessed across emergent latent classes. The study was a cross sectional survey of adolescents attending post-primary schools in England. A total of 679 took part in the study with an age range from 11 to 14 years. Pain was operationalised as the occurrence of pain for one day or more in the past month. Schoolchildren self-reported on the incidence of pain aided by a nordic manikin. A three-class model emerged as the best fit. Classes were labelled 'Pain free' (63.4%), 'Neck and back' pain (28.2%) and 'Widespread' pain (8.4%). The 'Widespread' pain class was significantly related with Age (OR=1.79; 95%CI 1.24-2.57), Sex (OR=0.35, 95%CI 0.16-0.79), bag weight to body weight (OR=1.12, 95%CI 1.03-1.22), bag carrying method (OR=2.08, 95%CI 1.08-3.97), Schoolwork difficult (OR=2.78, 95%CI 1.27-6.07), and headaches (OR=2.13, 95%CI 1.65-2.76). While Strengths and Difficulties Questionnaire scores (OR=1.05, 95%CI 1.01-1.11), and Headaches (OR=1.78, 95%CI 1.39-2.26) were significant for the 'Back and neck' class. It is suggested that research should seek to identify typical pain profiles for adolescents, rather than concentrating on specific pain sites since some risk factors may be obscured or inflated by inappropriately amalgamating or segregating pain sites.

A cross-sectional study of self-reported back and neck pain among English schoolchildren and associated physical and psychological risk factors.

This study set out to identify the associations between ergonomics and other factors with back and neck pain among schoolchildren. Self-reported questionnaires were used to record health outcomes and potential risk factors in state schools. Six hundred and seventy-nine schoolchildren from Surrey in the United Kingdom aged 11-14 years took part. Twenty-seven percent of children reported having neck pain, 18% reported having upper back pain, and 22% reported having low back pain. A forward stepwise logistic regression was performed with pain categories the dependent variables. Neck pain was significantly associated with school furniture features, emotional and conduct problems, family history of low back pain and previous treatment for musculoskeletal disorders. Upper back pain was associated with school bag weight (3.4-4.45 kg), school furniture features, emotional problems and previous treatment for musculoskeletal disorders. Low back pain was associated with school furniture features, emotional problems, family history and previous injury or accident. It is important to recognise the influence of physical, psychological and family factors in children's pain.

Wide-field Fizeau imaging telescope: experimental results.

A nine-aperture, wide-field Fizeau imaging telescope has been built at the Lockheed-Martin Advanced Technology Center. The telescope consists of nine, 125 mm diameter collector telescopes coherently phased and combined to form a diffraction-limited image with a resolution that is consistent with the 610 mm diameter of the telescope. The phased field of view of the array is 1 murad. The measured rms wavefront error is 0.08 waves rms at 635 nm. The telescope is actively controlled to correct for tilt and phasing errors. The control sensing technique is the method known as phase diversity, which extracts wavefront information from a pair of focused and defocused images. The optical design of the telescope and typical performance results are described.