John R. Fowler

The Sensitivity and Specificity of Ultrasound for the Diagnosis of Carpal Tunnel Syndrome: A Meta-analysis

BackgroundCarpal tunnel syndrome (CTS) is the most commonly diagnosed compression neuropathy of the upper extremity. Current AAOS recommendations are to obtain a confirmatory electrodiagnostic test in patients for whom surgery is being considered. Ultrasound has emerged as an alternative confirmatory test for CTS; however, its potential role is limited by lack of adequate data for sensitivity and specificity relative to electrodiagnostic testing.Questions/purposesIn this meta-analysis we determined the sensitivity and specificity of ultrasound in the diagnosis of CTS.MethodsA PubMed/MEDLINE search identified 323 articles for review. After applying exclusion criteria, 19 articles with a total sample size of 3131 wrists were included for meta-analysis. Three groups were created: a composite of all studies, studies using clinical diagnosis as the reference standard, and studies using electrodiagnostic testing as the reference standard.ResultsThe composite sensitivity and specificity of ultrasound for the diagnosis of CTS, using all studies, were 77.6% (95% CI 71.6–83.6%) and 86.8% (95% CI 78.9–94.8%), respectively.ConclusionsThe wide variations of sensitivities and specificities reported in the literature have prevented meaningful analysis of ultrasound as either a screening or confirmatory tool in the diagnosis of CTS. The sensitivity and specificity of ultrasound in the diagnosis of CTS are 77.6% and 86.8%, respectively. Although ultrasound may not replace electrodiagnostic testing as the most sensitive and specific test for the diagnosis of CTS given the values reported in this meta-analysis, it may be a feasible alternative to electrodiagnostic testing as the first-line confirmatory test.Level of Evidence Level III, systematic review of Level III studies. See Guidelines for Authors for a complete description of levels of evidence.

Ultrasound as a First-line Test in the Diagnosis of Carpal Tunnel Syndrome: A Cost-effectiveness Analysis

BackgroundThe American Academy of Orthopaedic Surgeons (AAOS) recommends that surgeons obtain a confirmatory test in patients for whom carpal tunnel surgery is being considered. The AAOS, however, does not specify a preferred test. Ultrasound reportedly causes less patient discomfort and takes less time to perform, while maintaining comparable sensitivity and specificity to electrodiagnostic testing (EDX).Questions/purposesWe determined whether ultrasound as a first-line diagnostic test is more cost-effective than using EDX alone or using ultrasound alone: (1) when used by a general practitioner; and (2) when used by a specialist.MethodsA fictional population of patients was created and each patient was randomly assigned a probability of having true-positive, false-positive, true-negative, and true-positive ultrasound and EDX tests over an expected range of sensitivity and specificity values using Monte Carlo methods. Charges were assigned based on Medicare charges for diagnostic tests and estimates of missed time from work.ResultsThe average charge for the use of ultrasound as a first-line diagnostic test followed by EDX for confirmation of a negative ultrasound test was

Comparison of Ultrasound and Electrodiagnostic Testing for Diagnosis of Carpal Tunnel Syndrome Study Using a Validated Clinical Tool as the Reference Standard

562.90 per patient in the general practitioner scenario and

Community-Acquired Methicillin-Resistant Staphylococcus aureus Infections of the Hand: Prevalence and Timeliness of Treatment

369.50 per patient in the specialist scenario, compared with

Bacteria Adhere Less to Barbed Monofilament Than Braided Sutures in a Contaminated Wound Model

400.30 and

The importance of surgical sequence in the treatment of lower extremity injuries with concomitant vascular injury: A meta-analysis

428.30 for EDX alone, respectively.ConclusionsThe use of diagnostic ultrasound as a first-line test for confirmation of a clinical diagnosis of carpal tunnel syndrome is a more cost-effective strategy in the specialist population and results in improved false-negative rates in the generalist population despite increased cost.Level of EvidenceLevel III, economic and decision analyses. See the Guidelines for Authors for a complete description of levels of evidence.

Epidemiology of adult acute hand infections at an urban medical center.

BACKGROUND Ultrasound examination is both accurate and cost-effective for the confirmation of a clinical diagnosis of carpal tunnel syndrome. Previous studies have shown electrodiagnostic testing and ultrasound to be similar with regard to sensitivity and specificity. The purpose of this study was to compare the sensitivity and specificity of ultrasound and electrodiagnostic testing by using a validated clinical diagnostic tool as the reference standard. METHODS All consecutive patients referred to an upper-extremity practice for electrodiagnostic testing for any reason over a three-month period were recruited to participate in this study. All patients were evaluated with the use of the Carpal Tunnel Syndrome 6 (CTS-6) clinical diagnostic tool, and a score of ≥12 was considered positive for carpal tunnel syndrome. A positive finding on ultrasound was considered to be a cross-sectional area of the median nerve, measured just proximal to the level of the pisiform, of ≥10 mm(2). A positive finding on electrodiagnostic testing was a distal motor latency of ≥4.2 ms and/or a distal sensory latency of ≥3.2 ms. Sensitivity, specificity, and accuracy were calculated for ultrasound and electrodiagnostic testing with use of the CTS-6 as the reference standard. RESULTS With use of the CTS-6 as the reference standard, ultrasound had a sensitivity of 89% and a specificity of 90% in our series of eighty-five patients. Electrodiagnostic testing had a sensitivity of 89% and a specificity of 80%. The positive predictive value of ultrasound was 94% compared with 89% for electrodiagnostic testing. The negative predictive value of ultrasound was 82% compared with 80% for electrodiagnostic testing. Ultrasound was accurate in seventy-six (89%) of the eighty-five cases whereas electrodiagnostic testing was accurate in seventy-three (86%) of the eighty-five cases (p = 0.5). CONCLUSIONS While ultrasound will not replace electrodiagnostic testing in complicated or unclear cases, in a select group of patients with a positive CTS-6, ultrasound can be used to confirm the diagnosis of carpal tunnel syndrome with better specificity and equal sensitivity as compared with those of electrodiagnostic testing. LEVEL OF EVIDENCE Diagnostic Level I. See Instructions for Authors for a complete description of levels of evidence.

Is Antibiotic Prophylaxis Necessary in Elective Soft Tissue Hand Surgery

PURPOSE The prevalence of community-acquired methicillin-resistant Staphylococcus aureus (ca-MRSA) appears to be increasing, but the timeliness of appropriate antibiotic delivery is often delayed. We retrospectively reviewed the prevalence of ca-MRSA infections in an urban setting, time from presentation to the hospital to appropriate antibiotic delivery, and differences in length of stay between the ca-MRSA and non-MRSA hand infections. METHODS We retrospectively reviewed all visits for hand infection cases to the emergency room of an urban academic medical center over a 12-month period. A formal hand infection algorithm was used in the treatment of each patient. All patients with culture-positive hand infections were included for evaluation. Infections determined to be nosocomial or not community-acquired were excluded. Patient demographics, laboratory studies, culture results, antibiotic delivery, and length of stay data were collected. RESULTS A total of 85 patients (55 male) with an average age of 39 years met the inclusion criteria. The overall prevalence rate of ca-MRSA hand infections was 55%. The average time to appropriate antibiotic delivery for ca-MRSA infection was 12 hours, versus 2.64 hours for non-MRSA hand infections (p > .5). The average length of stay was 4.0 days for ca-MRSA infections and 3.5 days for non-MRSA infections (p > .05). Univariate and multivariate analysis identified intravenous drug abuse and a serum white blood cell count of >8.7 as independent risk factors for ca-MRSA hand infections. CONCLUSIONS Community-acquired methicillin-resistant S. aureus infections of the hand continue to increase in urban settings. With the use of a formal hand infection treatment algorithm, we did not identify a statistical difference in appropriate antibiotic delivery time and length of stay between ca-MRSA and non-MRSA hand infections.

The Non-Surgical and Surgical Treatment of Tarsal Navicular Stress Fractures

BackgroundPrevious studies have found fewer clinical infections in wounds closed with monofilament suture compared with braided suture. Recently, barbed monofilament sutures have shown improved strength and increased timesavings over interrupted braided sutures. However, the adherence of bacteria to barbed monofilament sutures and other commonly used suture materials is unclear.Questions/PurposesWe therefore determined: (1) the adherence of bacteria to five suture types including a barbed monofilament suture; (2) the ability to culture bacteria after gentle washing of each suture type; and (3) the pattern of bacterial adherence.MethodsWe created an experimental contaminated wound model using planktonic methicillin-resistant Staphylococcus aureus (MRSA). Five types of commonly used suture material were used: Vicryl™, Vicryl™ Plus, PDS™, PDS™ Plus, and Quill™. To determine adherence, we determined the number of bacteria removed from the suture by sequential washes. Sutures were plated to determine bacterial growth. Sutures were examined under confocal microscopy to determine adherence patterns.ResultsThe barbed monofilament suture showed the least bacterial adherence of any suture material tested. Inoculated monofilament and barbed monofilament sutures placed on agar plates had less bacterial growth than braided suture, whereas antibacterial monofilament and braided sutures showed no growth. Confocal microscopy showed more adherence to braided suture than to the barbed monofilament or monofilament sutures.ConclusionsBarbed monofilament suture showed similar bacterial adherence properties to standard monofilament suture.Clinical RelevanceOur findings suggest barbed monofilament suture can be substituted for monofilament suture, at the surgeon’s discretion, without fear of increased risk of infection.

A Comparison of Three Diagnostic Tests for Carpal Tunnel Syndrome Using Latent Class Analysis.

OBJECTIVE The optimal sequence of surgical repair for lower extremity injury with associated vascular injuries is unclear. Lower extremity injury in our study is defined as femoral fracture, tibial fracture, and/or knee dislocation. Advocates of performing the vascular repair prior to lower extremity fixation argue that reversal of ischaemia in the limb is the most important factor in limb survival and should take precedence. Advocates of lower extremity fixation prior to revascularisation worry that the manipulation during fixation could disrupt the vascular repair and that total ischaemia time is more relative than absolute. METHODS A literature search was performed to identify studies with the following criteria: adult population, femoral fracture, tibial fracture, and/or knee dislocation with associated vascular injury, an intervention of fracture fixation or knee stabilisation prior to revascularisation and/or revascularisation prior to fracture fixation, and amputation as an outcome measurement. RESULTS 934 articles were identified and narrowed to 14 articles through exclusion criteria. Meta-analysis of the data shows no statistical difference in regards to the incidence of amputation between lower extremity fixation prior to revascularisation and revascularisation prior to fracture fixation. CONCLUSION Lower extremity injuries with associated vascular injury are uncommon. There has been a widespread but unsupported belief that manipulation and traction during lower extremity fixation will disrupt the vascular repair. Ischaemic time should be considered a relative, but not absolute predictor of amputation. Soft tissue injury and neurologic deficits have been found highly correlated with disability and amputation. Surgical sequence has not been shown to affect the rate of amputations in lower extremity fractures.