Reliability of the radiological assessments of radiolucency and loosening in total hip arthroplasty using PACS.

We evaluated the reliability of three commonly used radiological assessments of total hip arthroplasty (THA) using the electronic picture archiving and communications system (PACS). Thirty-three patients were selected at random at a mean of 7.2 years after THA. The Barrack, Gruen and Hodgkinson evaluations of cementing quality, loosening/radiolucency were graded. Three observers assessed each radiograph (one consultant orthopaedic surgeon, one senior orthopaedic registrar and one senior house officer). Four weeks after the initial assessment, each radiograph was reviewed a second time. The findings indicated that the intra- and inter-observer reliability of the Barrack, Gruen and Hodgkinson methods were questionable. Inter-observer reliability using the Gruen system was poor, using the Barrack system it was moderate to good, and fair to good using the Hodgkinson assessment. Intra-observer reliability was moderate to good for Barrack assessment, poor to good using Gruen zone assessments, but good to very good for the Hodgkinson assessment. The use of Barrack, Gruen and Hodgkinson assessments to evaluate femoral and acetabular loosening should be questioned since these exhibit limited inter- and intra-observer reliability on PACS radiographs, but of the three, the Hodgkinson system is the most reliable.

Emulation of dynamic wavefront disturbances using a deformable mirror.

Boundary-layer turbulence resulting from uneven airflow around window interfaces can impact airborne laser communications (lasercom). In the focal plane, these distortions can produce fast jitter and beam break-up, posing challenges for tracking and communications. We demonstrate an experimental emulator that reproduces aircraft aero-optical distortions using a deformable mirror. This boundary-layer emulator resides in a hardware testbed that experimentally mimics air-to-space lasercom links in a controlled, laboratory environment. The boundary-layer emulator operates in the 1.55-mum band and accurately recreates aero-optical distortions at a rate of 2 kilo-frames per second.

W.S.B.--a fluoroscopy C-arm communication strategy.

BACKGROUND: Good communication between an operating clinician and the attending radiographer when using C-arm fluoroscopy is vital. Efficient and safe use of ionising radiation protects all theatre staff. The object of this study was to design and test a single communication language for use in all fluoroscopy-assisted procedures. METHOD: A clinician guiding a radiographer performed a control 'no-rules' experiment of 56 targeting manoeuvres with a fluoroscopic C-arm on a scientific model. A single beam laser replaced the usual ionising radiation beam. The time taken for each targeting along with the laser exposure required was recorded. Following a period of instruction, the experiment was repeated using only our pre-defined communication strategy. The data was collected for statistical analysis. RESULTS: A statistically significant reduction was seen in the time taken for each targeting manoeuvre and the laser exposure required when using our strategy. CONCLUSION: This study shows that using our pre-prepared communication strategy could significantly improve efficiency and safety of fluoroscopic C-arm use.

Experimental comparison of tracking algorithms in the presence of aircraft boundary-layer distortions for emulated free-space laser communication links.

We report experiments comparing different focal plane array (FPA) tracking algorithms for emulated laser communication links between an aircraft and spacecraft. The links include look-angle-dependent phase disturbances caused by boundary-layer turbulence replicated by using a deformable mirror. Impairments from platform jitter, atmospheric scintillation, and propagation delay are also included. We study a hyperhemispherical dome geometry that provides a large field of regard but generates boundary-layer turbulence. Results from experiments comparing peak and centroid FPA tracking algorithms in various environments show that power delivered to the optical fiber varies with algorithm and look angle. An improvement in steady-state fiber-coupled power of up to 1.0 dB can be achieved through appropriate choice of algorithm. In a real system, this advantage could be realized by implementing a tracking processor that dynamically changes its tracking algorithm depending on look angle and other parameters correlated to boundary-layer turbulence.

Bridging-minimally invasive locking plate osteosynthesis (Bridging-MILPO): technique description with prospective series of 20 tibial fractures.

Bridging-MILPO provides an alternative to other internal and external devices in the management of tibial fractures. A pre-contoured, stainless steel locking compression plate (Synthes) is fed subcutaneously through a small incision from a site distant to the zone of injury across the fracture site, respecting the fracture haematoma. Two or three locking screws are placed specifically at the ends of the plate. This 'spring leaf' like construct allows micro-motion at the fracture site. This induces callus formation, initially on the opposite cortex from the plate, accelerated by the allowance of immediate full weight bearing post-operatively. Twenty cases were performed over a 3-year period. Excellent final results were obtained in 19 out of the 20 cases. Complications included two superficial wound infections, one delayed union and one case needed revision plating. No loss of reduction was seen in any of the cases.

Papaverine delivery to the internal mammary artery pedicle effectively treats spasm.

BACKGROUND: Left internal mammary artery spasm is well recognized during coronary artery bypass operations. Papaverine has been used by many surgeons to maximize mammary artery flow perioperatively, but the best delivery method is not known. We analyzed two techniques used at our institution. METHODS: Fifty-eight patients were randomized into three groups to compare papaverine's ability to prevent spasm and to treat established spasm. Group 1 was control and no treatment was employed. In group 2, papaverine was injected with a blunt needle through the endothoracic fascia parallel to the mammary artery before harvest to assess spasm prevention. In group 3, papaverine was delivered perivascular in an identical manner to group 2 but after the mammary artery was dissected from the chest wall. This group was an evaluation of spasm treatment. Drug dosage was the same for both groups and routine bypass grafting was performed. Before anastomosing the mammary artery to the left anterior descending artery, blood flow was recorded for 15 seconds and flow per minute calculated. Cardiopulmonary bypass pressures were maintained at 70 mm Hg during collection. RESULTS: Mean blood flows were: group 1 = 86.2 mL/min, group 2 = 122.5 mL/min, and group 3 = 139.7 mL/min. Left internal mammary artery flow in group 3 was statistically different from control (p = 0.0457). Group 2 flow approached but did not reach statistical significance (p = 0.0874). Mammary artery dissection times for the three groups were not different. CONCLUSIONS: Papaverine delivery to the left internal mammary artery after dissection treats spasm effectively, improves blood flow at the time of its anastamosis to the left anterior descending artery, and avoids any risk of intimal injury. Injection of papaverine before mammary artery harvest does not shorten dissection time, and flow is not statistically improved.

Posttraumatic stress disorder: do electrical startle responses and thyroid function usefully supplement self-report? A study of Vietnam War veterans.

OBJECTIVE: To investigate the usefulness of electrical startle responses and thyroid function as supplements to self-report measures of posttraumatic stress disorder (PTSD). METHOD: Invitations were sent to all New Zealand Vietnam War veterans known to be living in North Canterbury; 50 responded and the 35 living in or near Christchurch were included. Self-report measures of PTSD (the Davidson Trauma Scale (DTS) and the Symptom Check List (SCL-90-R) ), an eye blink electrical startle response and thyroid function were measured. The DTS was re-administered one to two weeks later to assess short-term test-retest reliability. Six months later the DTS and the electrical startle response were measured again. RESULTS: The veterans reported a wide range of PTSD severity, with 15/35 reporting prior diagnosis of PTSD. The DTS showed high short-term test-retest reliability (r = 0.93) and a moderate correlation after 6 months (r = 0.73). It also showed sensitivity to change; in one to two weeks the scores increased by nearly half a standard deviation, possibly because of an imminent "homecoming" march. The DTS and a PTSD scale from the SCL-90-R were highly correlated (r = 0.89). The total triiodothyronine (T3) to free thyroxine (T4) ratio measure of thyroid function correlated poorly with self-report (r < or = 0.27). The electrical startle response also correlated poorly with self-report (r < or = 0.26), showed low internal consistency between left and right sides (r = 0.43), and correlated 0.39 over six months. It was disliked by the veterans and had increased slightly at 6 month follow-up, perhaps because of sensitization. CONCLUSIONS: The DTS was reliable and correlated highly with the SCL-90-R PTSD scale. Neither thyroid function nor eye blink electrical startle correlated with each other or with self-report, and reliability was not good for electrical startle. These two measures do not appear to add anything useful to the assessment of PTSD.