Morphometry of thenar muscles by water bath ultrasonography in trapeziometacarpal osteoarthritis: intra- and inter-rater reliability

We studied the intra- and inter-rater reliability of muscle thickness and cross-sectional area measurements of thenar muscles with a water bath ultrasonography technique in eight healthy volunteers and 16 patients with trapeziometacarpal osteoarthritis. Thickness and cross-sectional area of the opponens pollicis, abductor pollicis brevis, flexor pollicis brevis, first dorsal interosseous and adductor pollicis muscle were measured. The results showed changes in the morphometric properties of the thenar muscles in patients with trapeziometacarpal osteoarthritis (TMC OA) compared with the healthy volunteers. In the dominant-sided patients (n = 14), there were lower cross-sectional area values for the abductor pollicis brevis and opponens pollicis muscles. In the non-dominant-sided patients (n = 10), there were lower cross-sectional area values for the abductor pollicis brevis and flexor pollicis brevis and lower muscle thickness of the abductor pollicis brevis. The water bath ultrasonography technique could be used to diagnose and treat diseases where changes in thenar muscle thickness and cross-sectional area can be expected.Level of evidence: III.

Prospective use of ultrasound imaging to detect bony hand injuries in adults

OBJECTIVE

We hypothesized that high-resolution linear ultrasound imaging performed by emergency sonologists would be accurate in the diagnosis of bony injuries of the hand.

METHODS

This was a prospective observational study of adult patients with injuries of the hand at an urban emergency department with trained emergency sonologists. After informed consent, high-frequency linear ultrasound was used to evaluate the bony structures below the area of injury or tenderness of the hand. The presence of a fracture or dislocation was recorded. A standard radiograph was taken subsequently and read by a blinded radiologist. Standard descriptive statistics with confidence intervals were calculated.

RESULTS

A total of 78 patients were enrolled in the study. The incidence of deformity was 28%; swelling, 90%; and erythema, 20%. Thirty patients had a total of 31 fractures: 21 metacarpal and 10 phalangeal. Ultrasound imaging identified 28 of 31 fractures found on standard radiographs, except for 1 patient's fractures, which were confirmed at surgery. One dislocation was found on ultrasound imaging and confirmed by radiographs. Ultrasound imaging showed the following accuracy for fracture: sensitivity, 90%; specificity, 98%; likelihood ratio (LR)(+), 42.5; and LR(-), 0.1. In comparison, individual physical examination findings of deformity, swelling, and erythema had a maximal LR(+) of 5.15 and minimum LR(-) of 0.51. One metacarpal fracture at the base of the first metacarpal, 1 spiral nondisplaced mid-third metacarpal fracture, and 1 distal tuft phalangeal fracture were missed by ultrasound imaging. There was 1 false-positive ultrasound finding.

CONCLUSIONS

Ultrasound imaging performed by emergency sonologists showed excellent sensitivity and specificity in the diagnosis of hand fractures.

The rate at which residents learn to use hand-held echocardiography at the bedside

PURPOSE

Because there is little information about the training that general internists require to perform hand-carried cardiac ultrasonography (HCU), we studied the rate of learning of a group of medical residents performing HCU after minimal formal training.

METHODS

Medical residents on the inpatient services at Johns Hopkins Bayview Medical Center received formal training in HCU consisting of 15-30 minutes of didactic instruction about the principles of echocardiography, followed by ongoing one-on-one instruction in performing HCU and subsequent ongoing one-on-one training from a certified echocardiography technician as they were doing scans. The residents were shown how to position the patient to obtain 2-dimensional echo images from the parasternal short and long axes and apical 4-chamber views, and how to obtain color-flow Doppler images across the mitral and aortic valves. Residents were asked to determine whether pericardial effusion was present and to assess left ventricular size, left ventricular function, and the mitral and aortic valves. The residents performed cardiac physical examination and HCU independently on patients who had a conventional transthoracic echocardiogram (CTTE) performed within 24 hours of the HCU. The residents' HCU results were compared with the CTTE results by a cardiologist specializing in echocardiography. The rates at which residents gained technical proficiency and skills in interpreting their studies were measured by linear regression to fit various outcome variables against their experience at scanning as gauged by the number of scans performed.

RESULTS

Thirty medical residents performed a total of 231 HCU studies. Linear regression models showed that the residents' overall technical proficiency skills improved at the rate of 0.79 (95% confidence interval [CI] 0.53-1.04) points on an overall assessment index (0-3 scale) per 10 scans completed. Interpretation accuracy improved at a rate of 1.01 (95% CI 0.69-1.39) points per 10 scans as measured by an interpretation accuracy index (0-3 scale). Because scanning efforts and instruction in HCU occurred during residents' usual rotation duties, some residents gathered experience in HCU slowly and sporadically.

CONCLUSION

This study, the first prospective, experimental effort of its kind, shows that residents as a group learned important aspects of HCU scanning and interpretation at a reasonably rapid rate.

Change in differential diagnosis and patient management with the use of portable ultrasound in a remote setting

OBJECTIVE

Physicians practicing in remote areas are typically limited in their choice of diagnostic tools. The goal of this study was to determine whether the use of a portable ultrasound (US) device on selected patients in a remote setting would alter physician diagnosis and management.

METHODS

This was a prospective observational study of the affects of US on physician decision making deep in the Amazon jungle. A battery-operated Sonosite 180 Plus with 2 interchangeable transducers (4-7-MHz broadband intercavitary transducer and 2-5-MHz broadband abdominal transducer) was used. The patient population consisted of local tribal people. Two of the physicians on the team performed all US examinations. Team physicians requesting US examinations filled out a survey before and after the US examination. Before the US, the referring physician filled out a survey describing the patient's initial complaint, pertinent past medical history and physical findings, and an initial (pre-US) differential diagnosis and planned treatment with expected disposition. After the results of the US were reviewed with the referring physicians, the doctors were asked to fill out the remainder of the survey, allowing comparison of pre- and post-US differential diagnosis, treatment plan, and disposition.

RESULTS

A total of 25 US studies were performed during this study (1 trauma US scan, 6 hepatobiliary studies, 5 transabdominal pelvic scans, 7 transvaginal pelvic studies, 3 renal studies, and 3 abdominal aortic scans). The monitor on the US unit experienced a rare failure shortly after being used at 17,000 ft and then 10 times at sea level, and no further US scans could be performed. US scan results dramatically altered the disposition of 7 patients, including 4 patients who avoided a potentially dangerous 2-day evacuation to more definitive medical care. Three patients were found to need rapid referral to the nearest clinic for surgical evaluation.

CONCLUSIONS

When used in a remote location, portable US provides a significant benefit that can dramatically alter disposition and treatment.