3-D CT is the Most Reliable Imaging Modality When Quantifying Glenoid Bone Loss

Background

Posttraumatic anterior shoulder instability is associated with anterior glenoid bone loss, contributing to recurrence. Accurate preoperative quantification of bone loss is paramount to avoid failure of a soft tissue stabilization procedure as bone reconstruction is recommended for glenoid defects greater than 20% to 27%.

Questions/purposes

We determined whether radiography, MRI, or CT was most reliable to quantify glenoid bone loss in recurrent anterior shoulder instability.

Methods

Seven intact fresh-frozen human cadaveric shoulders were imaged with radiography, MRI, CT, and three-dimensional (3-D) CT. Three sequential anterior glenoid defects then were created, measured, and the shoulders reimaged after each defect. Defect sizes were less than 12%, 12% to 25%, and 25% to 40%. The gold standard measurement was determined by comparing measurements taken on the cadaver by two surgeons using digital calipers with the measurements determined by using electronic digital calipers on the 3-D CT. This measurement was used for comparison of all estimations by the evaluators. Twelve independent blinded evaluators reviewed the 112 image sets and estimated the percent of glenoid bone loss. Images were scrambled and rereviewed by the same observers 2 months later to determine intraobserver reliability. We determined reliability with kappa values.

Results

Kappa values between predicted bone loss versus true loss (determined by our gold standard measurements) across all 12 raters for each modality were: 3-D CT, 0.50; CT, 0.40; MRI, 0.27; and radiographs, 0.15. Interobserver agreement (kappa) values were: 3-D CT, 0.54; CT, 0.47; MRI, 0.31; and radiographs, 0.15. The intraobserver agreement (kappa) values were: 3-D CT, 0.59; CT, 0.64; MRI, 0.51; and radiographs, 0.45.

Conclusions

Three-dimensional CT was the most reliable imaging modality for predicting glenoid bone loss. Regular CT was the second most reliable and reproducible modality.     

Laminar flow reduces cases of surgical site infections in vascular patients

Introduction

Numerous strategies are employed routinely in an effort to lower rates of surgical site infections (SSIs). A laminar flow theatre environment is generally used during orthopaedic surgery to reduce rates of SSIs. Its role in vascular surgery, especially when arterial bypass grafts are used, is unknown.

Methods

A retrospective review of a prospectively maintained database was undertaken for all vascular procedures performed by a single consultant over a one-year period. Cases were performed, via random allocation, in either a laminar or non-laminar flow theatre environment. Demographic data, operative data and evidence of postoperative SSIs were noted. A separate subgroup analysis was undertaken for patients requiring an arterial bypass graft. Univariate and multivariate logistical regression was undertaken to identify significant factors associated with SSIs.

Results

Overall, 170 procedures were analysed. Presence of a groin incision, insertion of an arterial graft and a non-laminar flow theatre were shown to be predictive of SSIs in this cohort. In the subgroup receiving arterial grafts, only a non-laminar flow theatre environment was shown to be predictive of an SSI.

Conclusions

This study suggests that laminar flow may reduce incidences of SSI, especially in the subgroup of patients receiving arterial grafts.     

Admission inflammatory markers and isolation of a causative organism in patients with spontaneous spinal infection

Introduction

The purpose of this study was to investigate the significance of the inflammatory markers on admission in the isolation of a causative pathogen in patients with spinal infection. Spinal infection is treated frequently at spinal units and can encompass a broad range of clinical entities. Its diagnosis is often delayed because of the difficulty of identifying the responsible pathogen.

Methods

Patients with spinal infection treated in our institution over a period of eight years were identified and their notes studied retrospectively. Admission C-reactive protein (CRP), white cell count (WCC) as well as co-morbidities and mode of pathogen identification were recorded. Overall, 96 patients were included in the study.

Results

The CRP levels on admission were correlated significantly with the overall potential for isolation of a pathogen (p<0.0001) and positive biopsy cultures (p=0.0016). Admission WCC levels were associated significantly with the overall potential for isolation of a pathogen (p=0.0003) and positive biopsy cultures (p=0.0023). Both CRP and WCC levels were significantly negatively correlated with the duration of the preceding symptoms (p=0.0003 and p<0.0001 respectively). Delay in presentation was significantly negatively correlated with organism isolation (p=0.0001). Multivariate analyses identified the delay in presentation as the strongest independent variable for organism isolation (p=0.014) in cases of spontaneous spinal infection when compared with the admission CRP level (p=0.031) and WCC (p=0.056).

Conclusions

In spontaneous spinal infection, delay in presentation is the strongest independent variable for organism isolation. High inflammatory marker levels on admission are a useful prognostic marker for the overall potential of isolating a causative organism either by blood cultures or by biopsy in patients with negative blood cultures. Furthermore, the admission inflammatory marker levels allow for treating surgeons to counsel their patients of the likelihood of achieving a positive microbiological yield from biopsy.     

Management of acute pain

Acute pain is an important fear for most patients and influences their recovery and overall experience. Poorly treated, it could lead to undesirable effects and patient dissatisfaction. Hence, it is important to understand, assess and treat acute pain effectively. Pain is regarded as the fifth vital sign and should be addressed as important as other vital parameters. Management of pain involves team work, including acute pain services, especially in dealing with complex problems. Management of pain ideally starts at the pre-assessment visit or from first presentation to the clinician. It is important to anticipate and treat acute pain effectively which may prevent the development of chronic pain syndromes. Patients should be given information about analgesic options, the risk:benefit ratio of the treatment options at the earliest opportunity and ideally have an individualized management plan.     

Theories of the pathogenesis of hepatic encephalopathy

The earliest hypothesis of the pathogenesis of HE implicated ammonia, although effects of appreciable concentrations of this neurotoxin did not resemble HE. Altered eurotransmission in the brain was suggested by similarities between increased GABA-mediated inhibitory neurotransmission and HE, specifically decreased consciousness and impaired motor function. Evidence of increased GABAergic tone in models of HE has accumulated; potential mechanisms include increased synaptic availability of GABA and accumulation of natural benzodiazepine receptor ligands with agonist properties. Pathophysiological concentrations of ammonia associated with HE, have the potential of enhancing GABAergic tone by mechanisms that involve its interactions with the GABAa receptor complex.     

A disintegrin and metalloprotease (ADAM) 33 protein in patients with pulmonary sarcoidosis

Background and objective: A disintegrin and metalloproteinase (ADAM) 33 is a susceptibility gene associated with inflammatory lung and skin diseases. It is selectively expressed in mesenchymal cells, and its metalloprotease activity has been linked to angiogenesis and tissue remodelling. A soluble form of ADAM33 (sADAM33) has been identified in the bronchoalveolar lavage fluid (BALF) of asthmatic patients, and its levels inversely correlate with lung function. Because of its association with inflammatory lung diseases, it was hypothesized that sADAM33 is elevated in BALF of patients with pulmonary sarcoidosis. Methods: After removal of Ig using Protein A/G and enrichment using Concanavalin A beads, sADAM33 was identified in BALF by Western blotting. A fluorescence resonance energy transfer peptide cleavage assay was used to assess ADAM33‐like activity in BALF. Results: sADAM33 protein in BALF was detected as a 25 kDa fragment, and levels were significantly increased in samples from sarcoid patients when compared to healthy controls (P < 0.05). Levels of sADAM33 were inversely correlated with lung function (FVC%) (P < 0.05) and DL_CO % predicted (P < 0.01). No difference in sADAM33 enzymatic activity was observed between healthy and sarcoid BALF samples. Conclusions: Release of sADAM33 is increased in sarcoid and may be associated with abnormal lung function. sADAM33 may be a biomarker of lung tissue inflammation and remodelling in sarcoid.