Novel Antibiotic-loaded Point-of-care Implant Coating Inhibits Biofilm

Background

Orthopaedic biomaterials are susceptible to biofilm formation. A novel lipid-based material has been developed that may be loaded with antibiotics and applied as an implant coating at point of care. However, this material has not been evaluated for antibiotic elution, biofilm inhibition, or in vivo efficacy.

Questions/purposes

(1) Do antibiotic-loaded coatings inhibit biofilm formation? (2) Is the coating effective in preventing biofilm in vivo?

Methods

Purified phosphatidylcholine was mixed with 25% amikacin or vancomycin or a combination of 12.5% of both. A 7-day elution study for coated titanium and stainless steel coupons was followed by turbidity and zone of inhibition assays against Staphylococcus aureus and Pseudomonas aeruginosa. Coupons were inoculated with bacteria and incubated 24 hours (N = 4 for each test group). Microscopic images of biofilm were obtained. After washing and vortexing, attached bacteria were counted. A mouse biofilm model was modified to include coated and uncoated stainless steel wires inserted into the lumens of catheters inoculated with a mixture of S aureus or P aeruginosa. Colony-forming unit counts (N = 10) and scanning electron microscopy imaging of implants were used to determine antimicrobial activity.

Results

Active antibiotics with colony inhibition effects were eluted for up to 6 days. Antibiotic-loaded coatings inhibited biofilm formation on in vitro coupons (log-fold reductions of 4.3 ± 0.4 in S aureus and 3.1 ± 0 for P aeruginosa in phosphatidylcholine-only coatings, 5.6 ± 0 for S aureus and 3.1 ± 0 for P aeruginosa for combination-loaded coatings, 5.5 ± 0.3 for S aureus in vancomycin-loaded coatings, and 3.1 ± 0 for P aeruginosa for amikacin-loaded coatings (p < 0.001 for all comparisons of antibiotic-loaded coatings against uncoated controls for both bacterial strains, p < 0.001 for comparison of antibiotic-loaded coatings against phosphatidylcholine only for S aureus, p = 0.54 for comparison of vancomycin versus combination coating in S aureus, P = 0.99 for comparison of antibiotic- and unloaded phosphatidylcholine coatings in P aeruginosa). Similarly, antibiotic-loaded coatings reduced attachment of bacteria to wires in vivo (log-fold reduction of 2.54 ± 0; p < 0.001 for S aureus and 0.83 ± 0.3; p = 0.112 for P aeruginosa).

Conclusions

Coatings deliver active antibiotics locally to inhibit biofilm formation and bacterial growth in vivo. Future evaluations will include orthopaedic preclinical models to confirm therapeutic efficacy.

Clinical Relevance

Clinical applications of local drug delivery coating could reduce the rate of implant-associated infections.     

Immunomodulatory Peptide IDR-1018 Decreases Implant Infection and Preserves Osseointegration

Background

Innate defense regulator peptide-1018 (IDR-1018) is a 12-amino acid, synthetic, immunomodulatory host defense peptide that can reduce soft tissue infections and is less likely to induce bacterial resistance than conventional antibiotics. However, IDRs have not been tested on orthopaedic infections and the immunomodulatory effects of IDR-1018 have only been characterized in response to lipopolysacharide, which is exclusively produced by Gram-negative bacteria.

Questions/purposes

We sought (1) to more fully characterize the immunomodulatory effects of IDR-1018, especially in response to Staphylococcus aureus; and (2) to determine whether IDR-1018 decreases S aureus infection of orthopaedic implants in mice and thereby protects the implants from failure to osseointegrate.

Methods

In vitro effects of IDR-1018 on S aureus were assessed by determining minimum inhibitory concentrations in bacterial broth without and with supplementation of physiologic ion levels. In vitro effects of IDR-1018 on macrophages were determined by measuring production of monocyte chemoattractant protein-1 (MCP-1) and proinflammatory cytokines by enzyme-linked immunosorbent assay. In vivo effects of IDR-1018 were determined in a murine model of S aureus implant infection by quantitating bacterial burden, macrophage recruitment, MCP-1, proinflammatory cytokines, and osseointegration in nine mice per group on Day 1 postimplantation and 20 mice per group on Day 15 postimplantation.

Results

IDR-1018 demonstrated antimicrobial activity by directly killing S aureus even in the presence of physiologic ion levels, increasing recruitment of macrophages to the site of infections by 40% (p = 0.036) and accelerating S aureus clearance in vivo (p = 0.008) with a 2.6-fold decrease in bacterial bioburden on Day 7 postimplantation. In vitro immunomodulatory activity of IDR-1018 included inducing production of MCP-1 in the absence of other inflammatory stimuli and to potently blunt excess production of proinflammatory cytokines and MCP-1 induced by lipopolysaccharide. Higher concentrations of IDR-1018 were required to blunt production of proinflammatory cytokines and MCP-1 in the presence S aureus. The largest in vivo immunomodulatory effect of IDR-1018 was to reduce tumor necrosis factor-α levels induced by S aureus by 60% (p = 0.006). Most importantly, IDR-1018 reduced S aureus-induced failures of osseointegration by threefold (p = 0.022) and increased osseointegration as measured by ultimate force (5.4-fold, p = 0.033) and average stiffness (4.3-fold, p = 0.049).

Conclusions

IDR-1018 is potentially useful to reduce orthopaedic infections by directly killing bacteria and by recruiting macrophages to the infection site.

Clinical Relevance

These findings make IDR-1018 an attractive candidate to explore in larger animal models to ascertain whether its effects in our in vitro and mouse experiments can be replicated in more clinically relevant settings.     

Randomized controlled trial of pharmacological replacement of melatonin for sleep disruption in individuals with tetraplegia

Objective

To determine the effectiveness of a melatonin agonist for treating sleep disturbances in individuals with tetraplegia.

Design

Placebo-controlled, double-blind, crossover, randomized control trial.

Setting

At home.

Participants

Eight individuals with tetraplegia, having an absence of endogenous melatonin production and the presence of a sleep disorder.

Interventions

Three weeks of 8 mg of ramelteon (melatonin agonist) and 3 weeks of placebo (crossover, randomized order) with 2 weeks of baseline prior to and 2 weeks of washout between active conditions.

Outcome

Change in objective and subjective sleep.

Measures

Wrist actigraphy, post-sleep questionnaire, Stanford sleepiness scale, SF-36.

Results

We observed no consistent changes in either subjective or objective measures of sleep, including subjective sleep latency (P = 0.55, Friedman test), number of awakenings (P = 0.17, Friedman test), subjective total sleep time (P = 0.45, Friedman test), subjective morning alertness (P = 0.35, Friedman test), objective wake after sleep onset (P = 0.70, Friedman test), or objective sleep efficiency (P = 0.78, Friedman test). There were significant increases in both objective total sleep time (P < 0.05, Friedman test), subjective time in bed (P < 0.05, Friedman test), and subjective sleep quality (P < 0.05, Friedman test), although these occurred in both arms. There were no significant changes in any of the nine SF-36 subscale scores (Friedman test, Ps >Bonferroni adjusted α of 0.005).

Conclusion

In this pilot study, we were unable to show effectiveness of pharmacological replacement of melatonin for the treatment of self-reported sleep problems in individuals with tetraplegia.

Trial Registration

ClinicalTrials.gov # {"type":"clinical-trial","attrs":{"text":"NCT00507546","term_id":"NCT00507546"}}NCT00507546.     

Does Vitamin E-blended UHMWPE Prevent Biofilm Formation?

Background

Biofilm-related periprosthetic infections are catastrophic to patients and clinicians. Data suggest the addition of vitamin E to UHMWPE may have the ability to reduce biofilm formation on the surface of UHMWPE; however, previous studies were performed using stagnant broth solutions that may not have simulated a physiologic environment. In addition, the observed differences in levels of bacterial attachment, though statistically significant, may not be clinically significant.

Questions/purposes

We blended vitamin E with UHMWPE material and tested it for the ability to resist biofilm formation using a clinical isolate of methicillin-resistant Staphylococcus aureus (MRSA). Three additional materials were tested for comparison: highly crosslinked UHMWPE, compression-molded UHMWPE, and polyetheretherketone. We also determined whether the surface roughness of these materials facilitated biofilm formation.

Methods

Using a flow cell system, samples of each material type were placed into separate chambers. A 10% solution of brain-heart infusion broth containing 10⁵ colony-forming units (CFUs)/mL was flowed through the flow cell over 48 hours. The number of bacteria that adhered to the surface was quantified and biofilm formation was observed qualitatively using scanning electron microscopy. Optical profilometry was used to determine the surface roughness of each material type.

Results

Vitamin E-blended UHMWPE did not reduce biofilm formation of a clinically relevant strain of MRSA compared to materials that did not have vitamin E. More specifically, vitamin E-blended materials had similar amounts of biofilm formation (~ 8 log₁₀ CFUs/cm²) compared to materials not containing vitamin E (~ 8.1 log₁₀ CFUs/cm²) (p > 0.4). The roughness of vitamin E-blended material surfaces (mean ± SD: 1.85 ± 0.46 µm) compared to that of materials without vitamin E (2.06 ± 1.24 µm) did not appear to influence biofilm formation.

Conclusions

Under physiologically relevant conditions, vitamin E-blended UHMWPE did not have the ability to reduce the formation of biofilms by MRSA.

Clinical Relevance

These data indicate that the addition of vitamin E to UHMWPE may not reduce clinically relevant rates of biofilm-related periprosthetic infections of total joint arthroplasty devices.     

Examining implicit bias of physicians who care for individuals with spinal cord injury: A pilot study and future directions

Context

Despite evidence that healthcare providers have implicit biases that can impact clinical interactions and decisions, implicit bias among physicians caring for individuals with spinal cord injury (SCI) has not been examined.

Objective

Conduct a pilot study to examine implicit racial bias of SCI physicians and its association with functioning and wellbeing for individuals with SCI.

Design

Combined data from cross-sectional surveys of individuals with SCI and their SCI physicians.

Setting

Four national SCI Model Systems sites.

Participants

Individuals with SCI (N = 162) and their SCI physicians (N = 14).

Outcome measures

SCI physicians completed online surveys measuring implicit racial (pro-white/anti-black) bias. Individuals with SCI completed questionnaires assessing mobility, physical independence, occupational functioning, social integration, self-reported health, depression, and life satisfaction. We used multilevel regression analyses to examine the associations of physician bias and outcomes of individuals with SCI.

Results

Physicians had a mean bias score of 0.62 (SD = 0.35), indicating a strong pro-white/anti-black bias. Greater physician bias was associated with disability among individuals with SCI in the domain of social integration (odds ratio = 4.80, 95% confidence interval (CI) = 1.44, 16.04), as well as higher depression (B = 3.24, 95% CI = 1.06, 5.41) and lower life satisfaction (B = −4.54, 95% CI= −8.79, −0.28).

Conclusion

This pilot study indicates that SCI providers are susceptible to implicit racial bias and provides preliminary evidence that greater implicit racial bias of physicians is associated with poorer psychosocial health outcomes for individuals with SCI. It demonstrates the feasibility of studying implicit bias among SCI providers and provides guidance for future research on physician bias and patient outcomes.     

Implementing a patient education intervention about Methicillin-resistant Staphylococcus aureus prevention and effect on knowledge and behavior in veterans with spinal cord injuries and disorders: A pilot randomized controlled trial

Objectives

To assess the feasibility and effect of a nurse-administered patient educational intervention about Methicillin-resistant Staphylococcus aureus (MRSA) prevention on knowledge and behavior of Veterans with spinal cord injuries and disorders (SCI/D).

Design

Blinded, block-randomized controlled pilot trial.

Setting

Two Department of Veterans Affairs (VA) SCI Centers.

Participants

Veterans were recruited March–September 2010 through referral by a healthcare provider from inpatient, outpatient, and residential care settings.

Intervention

Thirty participants were randomized to the nurse-administered intervention and 31 to the usual care group. The intervention included a brochure and tools to assist nurses in conducting the education.

Outcome measures

Pre- and post-intervention measurement of knowledge and behaviors related to MRSA and prevention strategies and feasibility measures related to implementation.

Results

Participants were primarily male (95.1%), white (63.9%), with tetraplegia (63.9%) and mean age and duration of injury of 64.3 and 20.5 years, respectively. The intervention groups mean knowledge score significantly increased between pre- and post-test (mean change score = 1.70, 95% confidence interval, CI 0.25–3.15) while the usual care groups score did not significantly change (mean change score = 1.45, 95% CI −0.08–2.98). However, the mean knowledge change between intervention and usual care groups was not significantly different (P = 0.81). Overall behavior scores did not significantly differ between treatment groups; however, the intervention group was more likely to report intentions to clean hands (90.0% vs. 64.5%, P = 0.03) and asking providers about MRSA status (46.7% vs. 16.1%, P = 0.01). Nurse educators reported that the quality of the intervention was high and could be implemented in clinical care.

Conclusions

A targeted educational strategy is feasible to implement in SCI/D clinical practices and may improve some participants’ knowledge about MRSA and increase intentions to improve hand hygiene and engagement with providers about their MRSA status.     

Assessment of passive knee stiffness and viscosity in individuals with spinal cord injury using pendulum test

Objective

Stiffness and viscosity represent passive resistances to joint motion related with the structural properties of the joint tissue and of the musculotendinous complex. Both parameters can be affected in patients with spinal cord injury (SCI). The purpose of this study was to measure passive knee stiffness and viscosity in patients with SCI with paraplegia and healthy subjects using Wartenberg pendulum test.

Design

Non-experimental, cross-sectional, case–control design.

Setting

An outpatient physical therapy clinic, University of social welfare and Rehabilitation Science, Iran.

Patients

A sample of convenience sample of 30 subjects participated in the study. Subjects were categorized into two groups: individuals with paraplegic SCI (n = 15, age: 34.60 ± 9.18 years) and 15 able-bodied individuals as control group (n = 15, age: 30.66 ± 11.13 years).

Interventions

Not applicable.

Main measures

Passive pendulum test of Wartenberg was used to measure passive viscous-elastic parameters of the knee (stiffness, viscosity) in all subjects.

Results

Statistical analysis (independent t-test) revealed significant difference in the joint stiffness between healthy subjects and those with paraplegic SCI (P = 0.01). However, no significant difference was found in the viscosity between two groups (P = 0.17). Except for first peak flexion angle, all other displacement kinematic parameters exhibited no statistically significant difference between normal subjects and subjects with SCI.

Conclusions

Patients with SCI have significantly greater joint stiffness compared to able-bodied subjects.     

The influence of shoulder pain on functional limitation,perceived health,and depressive mood in patients with traumatic paraplegia

Objective

To assess whether functional activity, perceived health, and depressive symptoms differ between individuals with traumatic paraplegia with and without shoulder pain.

Design

Cross sectional and comparative investigation using the unified questionnaire.

Setting

Neural Regeneration and Repair Division unit of Taipei Veterans General Hospital in Taiwan.

Participants

Seventy-six patients with paraplegia (23 with and 53 without shoulder pain) who had experienced spinal cord injury at American Spinal Injury Association Impairment Scale T2 to T12 neurologic level (at least 6 months previously).

Outcome measures

Spinal Cord Independence Measure (SCIM), a single item from the Medical Outcomes Study 36-Item Short-Form Health Survey, and Patient Health Questionnaire-9 (PHQ-9) depression scale.

Results

Shoulder pain was prevalent in 30% patients. Patients with shoulder pain had significantly worse perceived health and greater depressive symptoms than those without. No significant difference was found in functional ability between groups. Greater shoulder pain intensity was related to higher depressive scores (r = 0.278, P = 0.017) and lower self-perceived health scores (r = −0.433, P < 0.001) but not SCIM scores (P = 0.342).

Conclusion

Although shoulder pain was unrelated to functional limitation, it was associated with lower perceived health and higher depressive mood levels.     

Twenty Percent of Patients May Remain Colonized With Methicillin-resistant Staphylococcus aureus Despite a Decolonization Protocol in Patients Undergoing Elective Total Joint Arthroplasty

Background

Staphylococcus aureus is the most commonly isolated organism in periprosthetic joint infection (PJI). Resistant strains such as methicillin-resistant S aureus (MRSA) are on the rise, and many programs have instituted decolonization protocols. There are limited data on the success of S aureus nasal decolonization programs and their impact on PJI.

Questions/purposes

The purposes of this study were to (1) determine the proportion of patients successfully decolonized using a 2-week protocol; (2) compare infection risks between our surveillance and decolonization protocol group against a historical control cohort to evaluate changes in proportions of S aureus infections; and (3) assess infection risk based on carrier type, comparing S aureus carriers with noncarrier controls.

Methods

We retrospectively evaluated a group of 3434 patients who underwent elective primary and revision hip and knee arthroplasty over a 2-year period; each patient in the treatment group underwent a surveillance protocol, and a therapeutic regimen of mupurocin and chlorhexidine was instituted when colonization criteria were met. A 2009 to 2010 comparative historical cohort was chosen as the control group. We compared risks of infection between our treatment group and the historical control cohort. Furthermore, in patients who developed surgical site infections (SSIs), we compared the proportions of each S aureus type between the two cohorts. Finally, we compared infection rates based on carrier status. Surveillance for infection was carried out by the hospital infection control coordinator using the Centers for Disease Control and Prevention (CDC) criteria. During the time period of this study, the CDC defined hospital-acquired infection related to a surgical procedure as any infection diagnosed within 1 year of the procedure. With the numbers available, we had 41% power to detect a difference of 0.3% in infection rate between the treatment and control groups. To achieve 80% power, a total of 72,033 patients would be needed.

Results

Despite the protocol, 22% (26 of 121) of patients remained colonized with MRSA. With the numbers available, there were no differences in infection risk between the protocoled group (27 of 3434 [0.8%]) and the historical control group (33 of 3080 [1.1%]; relative risk [RR], 0.74; 95% confidence interval [CI], 0.44–1.22; p = 0.28). In terms of infecting organism in those who developed SSI, S aureus risk decreased slightly (treatment: 13 of 3434 patients [0.38%]; control: 21 of 3080 patients [0.68%]; RR, 0.56; CI, 0.28–1.11; p = 0.11). Within the protocoled group, carriers had a slightly higher risk of developing SSI (carrier: seven of 644 [1.1%]; noncarrier: 18 of 2763 [0.65%]; RR, 1.77; CI, 0.74–4.24; p = 0.20).

Conclusions

The screening and decolonization protocol enabled a substantial reduction in nasal carriage of MRSA, but some patients remained colonized. However, our nasal decolonization protocol before elective total joint arthroplasty did not demonstrate a decrease in the proportion of patients developing SSI. Future meta-analyses and systematic reviews will be needed to pool the results of studies like these to ascertain whether small improvements in infection risk are achieved by protocols like ours and to determine whether any such improvements warrant the costs and potential risks of surveillance and intervention.

Level of Evidence

Level III, therapeutic study.     

Trunk strength and function using the multidirectional reach distance in individuals with non-traumatic spinal cord injury

Context

Trunk control is essential to engage in activities of daily living. Measuring trunk strength and function in persons with spinal cord injury (SCI) is difficult. Trunk function has not been studied in non-traumatic SCI (NTSCI).

Objectives

To characterize changes in trunk strength and seated functional reach in individuals with NTSCI during inpatient rehabilitation. To determine if trunk strength and seated reach differ between walkers and wheelchair users. To explore relationships between trunk and hip strength and seated functional reach.

Design

Observational study.

Setting

Two SCI rehabilitation facilities.

Participants

32 subacute inpatients (mean age 48.0 ± 15.4 years).

Outcome measures

Isometric strength of trunk and hip and function (Multidirectional Reach Test: MDRT) were assessed at admission and within 2 weeks of discharge. Analysis of variance was conducted for admission measures (MDRT, hip and trunk strength) between walkers and wheelchair users. Changes in MDRT, hip and trunk strength were evaluated using parametric and non-parametric statistics. The level of association between changes in values of MRDT and strength was also examined.

Results

Significant differences between walkers and wheelchair users were found for strength measures (P < 0.05) but not for MDRT. Left- and right-sided reaches increased in wheelchair users only (P < 0.05). Associations between changes in hip strength, trunk strength, and reach distance were found (R = 0.67–0.73).

Conclusion

In clinical settings, it is feasible and relevant to assess trunk, hip strength, and MRDT. Future studies require strategies to increase the number of participants assessed, in order to inform clinicians about relevant rehabilitation interventions.     

Evaluation of bone mineral loss in patients with chronic traumatic spinal cord injury in Iran

Objectives

We described the associations between demographic and injury-related factors on bone mineral density (BMD) of the spine and the hip among adult patients with chronic spinal cord injury (SCI).

Design

BMD in spinal and femoral bone sites were assessed. Multivariate analysis was performed to evaluate the relationship between anthropometric and injury-related factors with BMD. Serum level and amount of dietary intake of calcium, phosphor, and 25-hydroxy vitamin D were measured.

Setting

A referral tertiary rehabilitation center in Iran.

Participants

Patients with SCI who had no previous history of endocrine disorders and were not on specific medications entered the investigation. Those with non-traumatic SCI, pregnant, or with substance dependency were excluded as well.

Interventions

No interventions were applied.

Main study outcome measures

Dual X-ray absorptiometry was performed to estimate BMD. Body mass index was positively associated with higher femoral (P < 0.01, r = 0.56) and hip (P < 0.0001, r = 0.82) BMD only in female participants. The high prevalence of vitamin D deficiency (60%) was noticeable.

Results

Older male patients revealed lower BMD only in spinal vertebrae (P < 0.02, r = −0.21). A significant higher BMD loss in lumbar vertebras in male patients with complete spinal cord lesion (P < 0.009) was detected. Spinal reduction of BMD was more severe when the level of injury was above T6 (P < 0.02).

Conclusion

Along with the clarification of age, gender, post injury duration, and the other factors'' effect on the BMD in the SCI patients, here we have also shown the noticeable prevalence of the 25-hydoxy vitamin D deficiency in these patients which needs attention.     

A preliminary comparison of myoelectric and cyclic control of an implanted neuroprosthesis to modulate gait speed in incomplete SCI

Objective

Explore whether electromyography (EMG) control of electrical stimulation for walking after incomplete spinal cord injury (SCI) can affect ability to modulate speed and alter gait spatial-temporal parameters compared to cyclic repetition of pre-programmed stimulation.

Design

Single case study with subject acting as own concurrent control.

Setting

Hospital-based biomechanics laboratory.

Participants

Single subject with C6 AIS D SCI using an implanted neuroprosthesis for walking.

Interventions

Lower extremity muscle activation via an implanted system with two different control methods: (1) pre-programmed pattern of stimulation, and (2) EMG-controlled stimulation based on signals from the gastrocnemius and quadriceps.

Outcome measures

Gait speed, distance, and subjective rating of difficulty during 2-minute walks. Range of walking speeds and associated cadences, stride lengths, stride times, and double support times during quantitative gait analysis.

Results

EMG control resulted in statistically significant increases in both walking speed and distance (P < 0.001) over cyclic stimulation during 2-minute walks. Maximum walking speed with EMG control (0.48 m/second) was significantly (P < 0.001) faster than the fastest automatic pattern (0.39 m/second), with increased cadence and decreased stride and double support times (P < 0.000) but no change in stride length (z = −0.085; P = 0.932). The slowest walking with EMG control (0.25 m/second) was virtually indistinguishable from the slowest with automatic cycling (z = −0.239; P = 0.811).

Conclusion

EMG control can increase the ability to modulate comfortable walking speed over pre-programmed cyclic stimulation. While control methods did not differ at the lowest speed, EMG-triggered stimulation allowed significantly faster walking than cyclic stimulation. The expanded range of available walking speeds could permit users to better avoid obstacles and naturally adapt to various environments. Further research is required to definitively determine the robustness, generalizability, and functional implications of these results.     

Association between alendronate,serum alkaline phosphatase level,and heterotopic ossification in individuals with spinal cord injury

Context/objective

Only sparse evidence exists regarding the effectiveness of oral alendronate (ALN) in the prevention of heterotopic ossification (HO) in patients with spinal cord injury (SCI). The objective of this study is to investigate the protective effect of oral ALN intake on the appearance of HO in patients with SCI.

Study design

Retrospective database review.

Setting

A Spinal Cord Unit at a Rehabilitation Hospital.

Participants

Two hundred and ninety-nine patients with SCI during acute inpatient rehabilitation.

Interventions

Administration of oral ALN.

Outcome measures

The incidence of HO during rehabilitation was compared between patients with SCI receiving oral ALN (n = 125) and patients with SCI not receiving oral ALN (n = 174). The association between HO and/or ALN intake with HO risk factors and biochemical markers of bone metabolism were also explored.

Results

HO developed in 19 male patients (6.35%), however there was no significant difference in the incidence of HO in patients receiving oral ALN or not. The mean odds ratio of not developing versus developing HO given ALN exposure was 0.8. Significant correlation was found between abnormal serum alkaline phosphatase (ALP) levels and HO appearance (P < 0.001) as well as normal serum ALP and ALN intake (P < 0.05).

Conclusion

Even though there was no direct prevention of HO in patients with SCI by oral ALN intake, abnormal serum ALP was found more frequently in patients with HO development and without oral ALN intake. This evidence could suggest that ALN may play a role in preventing HO, especially in patients with acute SCI with increasing levels of serum ALP.     

The lifetime risk of pneumonia in patients with neuromuscular scoliosis at a mean age of 21?years: the role of spinal deformity surgery

Background

Patients with neuromuscular disorders often have an increased risk of pneumonia and decreased lung function, which may further be compromised by scoliosis. Scoliosis surgery may improve pulmonary function in otherwise healthy patients, but no study has evaluated its effect on the risk of pneumonia in patients with neuromuscular scoliosis (NMS).

Methods

The patient charts of 42 patients (mean age 14.6 years) who had undergone surgery for severe NMS (mean scoliosis 86°) were retrospectively reviewed from birth to a mean of 6.1 years (range 2.8–9.5) after scoliosis surgery. The main outcome was radiographically confirmed pneumonia as a primary cause for hospitalization. We excluded postoperative (3 months) pneumonia from the analyses.

Results

The lifetime annual incidence of pneumonia was 8.0/100 before and 13.4/100 after scoliosis surgery (p > 0.10). The mean number of hospital days per year due to pneumonia were 0.59 (SD 2.3) before scoliosis surgery and 2.24 (SD 6.9) after surgery (p > 0.10). Multivariate analysis demonstrated that lifetime risk factors for pneumonia were epilepsy (RR 15.2, 95 % CI 1.3–176.8, p = 0.027), non-cerebral palsy (CP) etiology (RR = 10.2, 95 % CI 3.2–32.7, p < 0.001) and major scoliosis (main curve >70°; RR = 11.3, 95 % CI 1.8–70.7, p = 0.01).

Conclusions

Epilepsy, non-CP etiology and major scoliosis are significant risk factors for pneumonia in patients with NMS. Scoliosis surgery does not decrease the incidence of pneumonia in patients with severe NMS.

Level of Evidence

Retrospective comparative study, Level III.

Electronic supplementary material

The online version of this article (doi:10.1007/s11832-015-0682-8) contains supplementary material, which is available to authorized users.     

A Study of Microbial Colonisation of Orthopaedic Tourniquets

INTRODUCTION

Tourniquets are employed widely in orthopaedic surgery. The use of the same tourniquet on a repetitive basis without a standard protocol for cleaning may be a source of cross-infection. This study examines the contamination of the tourniquets in our institution.

MATERIALS AND METHODS

Agar plates were used to take samples from 20 tourniquets employed in orthopaedic procedures. Four sites on each tourniquet were cultured and incubated at 37°C for 48 h.

RESULTS

All sampled tourniquets were contaminated with colony counts varying from 9 to > 385. Coagulase-negative Staphylococcus spp. were the most commonly grown organisms from the tourniquets (96%).Some tourniquets had growths of important pathogens including methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas spp., and S. aureus. On cleaning five tourniquets with Clinell (detergent and disinfectant) wipes (GAMA Healthcare Ltd, London, UK), there was a 99.2% reduction in contamination of the tourniquets 5 min after cleaning.

CONCLUSIONS

In addition to the manufacturers'' guidelines, we recommend the cleaning of tourniquets with a disinfectant wipe before every case.     

Biofilm Growth Has a Threshold Response to Glucose in Vitro

Background

Hyperglycemia is a risk factor for nosocomial infections with known host effects. Increased glucose levels also increase pathogenicity of infecting microbes through greater biofilm formation. The dose response of biofilm formation to glucose concentration is not known.

Questions/purposes

We asked: What is the relationship between the amount of biofilm formed by Staphylococcus epidermidis and Staphylococcus aureus and change in glucose concentration in the clinically important range of 20 to 300 mg/dL?

Methods

This experiment studied biofilm formation by S epidermidis and S aureus in Lennox broth medium supplemented with increasing glucose concentrations from 0 to 320 mg/dL in 20 mg/dL intervals. Biofilm was grown for 24 hours for S epidermidis and 48 hours for S aureus. Biofilms were heat fixed, stained with 0.1% crystal violet, and washed with deionized water. The dye was then extracted with 30% acetic acid. Visual light absorption of the extracted crystal violet dye at 600 nm was used to quantify the biofilm biomass. The effect of glucose concentration on the amount of biofilm mass produced was analyzed using ANOVA and Tukey’s test.

Results

Biofilm mass was increased at higher glucose concentration for both species with a threshold response at 0 to 20 and 160 to 200 mg/dL for S epidermidis and 200 to 240 mg/dL for S aureus.

Conclusions

Increased biofilm growth by S aureus and S epidermidis has a threshold response at clinically important concentrations.

Clinical Relevance

Postoperative hyperglycemia may increase the risk for implant infection through increased pathogenicity of intraoperative wound contaminants in addition to compromising host immune status.     

Spinal deformity progression after posterior segmental instrumentation and fusion for idiopathic scoliosis

Study design

Retrospective chart and radiographic review.

Purpose

To assess the incidence of and variables associated with spinal deformity progression after posterior segmental instrumentation and fusion at a single institution. Progression of the scoliotic deformity after posterior instrumented spinal fusion has been described. Recent studies have concluded that segmental pedicle screw constructs are better able to control deformity progression.

Methods

Retrospective review of a consecutive series of idiopathic scoliosis patients (n = 89) with major thoracic curves (Lenke types 1–4) treated with posterior segmental instrumentation and fusion. Deformity progression was defined as a 10° increase in Cobb angle between the first-erect and 2-year post-operative radiographs. Clinical and radiographic data between the two cohorts (deformity progression versus stable) were analyzed to determine the variables associated with deformity progression.

Results

Patients in the deformity progression group (n = 13) tended to be younger (median 13.7 vs. 14.7 years) and experienced a significant change in height (p = 0.01) during the post-operative period compared to the stable group (n = 76). At 2-years post-op, the patients in the deformity progression group had experienced a significantly greater change in upper instrumented vertebra (UIV) angulation, lower instrumented vertebra (LIV) angulation, and apical vertebral translation (AVT). Two-year post-op Scoliosis Research Society questionnaire (SRS-22) scores in the appearance domain were also significantly worse in the deformity progression group. Patients in the deformity progression group had a significantly greater difference between the lowest instrumented vertebra and stable vertebra compared to patients in the stable group (p = 0.001).

Conclusions

Deformity progression after posterior spinal fusion does occur after modern segmental instrumentation. Segmental pedicle screw constructs do not prevent deformity progression. Skeletally immature patients with a significant growth potential are at the highest risk for deformity progression. In immature patients, extending the fusion distally to the stable vertebra may minimize deformity progression.

Level of evidence

Level III.     

Vitamin D status in pediatric osteoarticular tuberculosis

Background

Tubercular patients, in general, have been demonstrated with lower serum levels of vitamin D, but the levels in osteoarticular tuberculosis (TB) in children are largely unknown. We aimed to determine serum vitamin D status in pediatric cases with osteoarticular TB.

Methods

The values of serum vitamin D were estimated in 100 children with osteoarticular TB. The patients were divided into three groups based on gender, age, and site to assess variations of vitamin D levels in pediatric osteoarticular TB.

Results

Hypovitaminosis D was associated with active osteoarticular TB in children. The mean vitamin D levels were 42.165 nmol/L. There were no statistical difference between mean vitamin D levels in boys and girls (p value = 0.6143); age groups <5 and 5–12 years (p value = 0.3857); or spinal and non-spinal osteoarticular groups (p value = 0.8350).

Conclusions

Active osteoarticular TB in children was also associated with hypovitaminosis D. The correlation between hypovitaminosis D and osteoarticular TB appears to be more disease specific rather than host specific.     

Dermatological problems following spinal cord injury in Korean patients

Objective

To identify dermatological conditions following spinal cord injury (SCI) and analyze these conditions in relation to various characteristics of SCI.

Design

Retrospective chart review.

Setting

National Health Insurance Corporation Ilsan Hospital of Korea, Rehabilitation Center, Spinal Cord Unit.

Participants

Patients treated for SCI who were referred to dermatology for dermatological problems, 2000–2012.

Results

Of the 1408 SCI patients treated at the spinal cord unit, 253 patients with SCI were identified to have been referred to dermatology for skin problems and a total of 335 dermatological conditions were diagnosed. The most common dermatological finding was infectious (n = 123, 36.7%) followed by eczematous lesions (n = 109, 32.5%). Among the infectious lesions, fungal infection (n = 76, 61.8%) was the most common, followed by bacterial (n = 27, 21.9%) lesions. Seborrheic dermatitis (n = 59, 64.1%) was the most frequent eczematous lesion. Ingrown toenail occurred more frequently in tetraplegics whereas vascular skin lesions occurred more commonly in patients with paraplegia (P < 0.05). Xerotic dermatitis showed a higher occurrence within 12 months of injury rather than thereafter (P < 0.05). Of these, 72.4% of the infectious and 94.7% of the fungal skin lesions manifested below the neurological level of injury (NLI; P < 0.001) and 61.5% of the eczematous lesions and 94.9% of seborrheic dermatitis cases occurred above the NLI (P < 0.001). There was no significant difference in dermatological diagnoses between patients with neurologically complete and incomplete SCI.

Conclusion

The most common dermatological condition in patients with SCI among those referred to dermatology was fungal infection, followed by seborrheic dermatitis. Although dermatological problems after SCI are not critical in SCI outcome, they negatively affect the quality of life. Patients and caregivers should be educated about appropriate skin care and routine dermatological examinations.