Reliability of humeral head measurements performed using two- and three-dimensional computed tomography in patients with shoulder instability.

PURPOSE: The aim of the study was to compare two measurement methods of humeral head defects in patients with shoulder instability. Intra- and inter-observer reliability of humeral head parameters were performed with the use of 2D and 3D computed tomography. METHODS: The study group was composed of one hundred humeral heads measured with the use of preoperative 2D and 3D computed tomography by three independent observers (two experienced and one inexperienced). All observers repeated measurements after 1 week. The intra-class correlation coefficient (ICC) and the minimal detectable change with 95% confidence (MDC95%) were used for statistical analysis of diagnostic agreement. RESULTS: For 3D inter-observer reliability, ICC values were "excellent" for all parameters and MDC95% values were "excellent" or "reasonable." All intra-observer ICC and MDC95% values for 3D were "excellent" for experienced and inexperienced observers. For 2D-CT, ICC values were usually "good" or "moderate" with MDC95% values higher than 10 or 30%. CONCLUSIONS: Three-dimensional CT measurements are more reliable than 2D for humeral head and Hill-Sachs lesion assessment. This study showed that 2D measurements, even performed by experienced observers (orthopaedic surgeons), are burdened with errors. The 3D reconstruction decreased the risk of error by eliminating inaccuracy in setting the plane of the measurements.

Oil sands tailings pond sediment toxicity to early life stages of northern pike (Esox lucius).

The Athabasca River in Alberta flows through natural sources of eroding oil sands bitumen and oil sands mining operations that may result in low level contamination of surface waters. Northern pike (Esox lucius) are apex predators and important food and game fish species native to the Athabasca River system. This species has the potential to be exposed to both natural and anthropogenic sources of contamination from oil sands related materials throughout its life cycle. Pike are difficult to rear in the laboratory and little information exists on the toxicity of oil sands related materials to this key indigenous fish species. In this study, the potential effects of two sediment samples collected from different areas of one tailings pond in the Athabasca oil sands area are assessed in a daily renewal bioassay on early life stages of northern pike. Gametes were collected from spawning wild pike captured from a reference site outside of the oil sands area. Fertilized eggs were exposed to control water or increasing concentrations of tailings pond sediments for 21days, coinciding with initiation of exogenous feeding and completion of yolk absorption. Developing fish were examined for survival and changes in body weight, length, and development. Embryos exhibited increased developmental abnormalities and decreased growth and survival with increasing sediment concentration. Both sediment samples had similar levels of naphthenic acids and similar types of PAHs, with alkylated PAHs dominating. However, concentrations of total and alkylated PAHs differed between sediment samples and were related to increasing developmental abnormalities and decreased growth and survival. This is consistent with developmental changes observed with exposure to PAHs in other fish species. These results provide information on the effects of tailings pond sediments comprising mixtures of PAHs and alkylated PAHs on the development and survival of a key species in the northern aquatic ecosystem.

The experimental reconstruction of articular cartilage using autogenous periosteal and perichondreal implants.

Injured cartilage has a limited capacity to heal itself. Untreated damage leads to secondary osteoarthritis. There is a need to find a way to reconstruct cartilage in order to prevent secondary osteoarthritis. The aim this study was to evaluate and compare the chondrogenic potential of three different cell materials: perichonrdrial grafts, periosteal grafts and bone marrow in situ. The mesenchemal cells contained in these materials can differentiate in the joint environment into chondrocytes and rebuild articular cartilage.
Forty nine (49) White New Zealand rabbits were used in our experiment. An osteochondrial (full-thickness) defect was created in the joint surface of both ends of the femoral bone. The animals were divided according to the procedure used:
I - cartilage reconstruction by periosteal grat,
II - cartilage reconstruction by perichondrial graft,
III - no graft.
The joint was not immobilized after surgery. Follow-up exams were performed at 4, 8, and 12 weeks. The results were evaluated macroscopically and microscopically.
The results pointed to the chondrogenic potential of periosteum and perichondrium after grafting to cartilage defects. On gross examination the articular surface was found to be reconstructed. Microscopic examination revealed regeneration, with the formation of hyaline-like cartilage. Regenerating tissue was also found in the group without grafts. The structure resembled normal articular cartilage; however, neither the joint surface nor the subchondrial bone were fully reconstructed. No qualitative or quantitative differences were found between the groups treated with periosteal and perichondral grafts.
Our study confirmed that grafts of periosteum or perichondrium have chondrogenic potential, i.e. the ability to generate cartilage tissue whose features are similar to those of the hyaline chondrial tissue in the joint. Both materials have similar chondrogenic potential. The chondrogenic properties of perichondrium and perisostem produce better results in the various categories in comparison to those of bone marrow.

[Free vascularized joint transfer during surgery for hypoplastic thumb]. / Wolny unaczyniony przeszczep stawu w leczeniu operacyjnym wrodzonej hipoplazji kciuka.

Hypoplasia and aplasia of the thumb constitute approximately 11% of congenital disorders of the upper extremity. Surgical treatment depends on type of disorder in Blauth classification used in our Department. Soft tissue procedures and pollicisations are performed most often. Microsurgical transplantation of interphalangeal joint from the toe is an alternative. This paper describes a case of microsurgical treatment in 20 years old patient with hypoplastic thumb. Two months after surgery the range of motion in transplanted joint was between 20 and 75 degrees.

Microvascular application of the nonreversed vein graft.

To determine the applicability of the nonreversed vein graft technique to 1-mm-diameter vessels, 24 New Zealand White rabbits underwent bilateral replacement of 2-cm defects in the femoral artery with vein graft conduits. On one side a standard reversed vein graft (RVG) was employed, and on the other side a nonreversed vein graft (NRVG) was placed after valve disruption with a Hall valvulotome. Patency rates were not statistically different (RVG 87 percent, NRVG 96 percent, p > 0.1). Electron and light microscopy revealed similar endothelial damage and time to endothelial recovery between the two techniques. There was no difference in flow volume between the two techniques. We conclude that the NRVG technique has acceptable patency rates in 1-mm-diameter vessels within the parameters of this study but that further research is required to determine clinical applicability.

Most comfortable loudness shift as a measure of speech attenuation by hearing protectors.

The feasibility of using most comfortable loudness (MCL) as a real-world measure of speech attenuation introduced by hearing protection devices (HPDs) was studied. The authors compared three insert HPDs and an earmuff under three test conditions: (a) monaural earphone listening, (b) binaural earphone listening, and (c) sound field listening. The earmuff was used only in the sound-field condition. In addition, three sets of fitting instructions were utilized. Twelve normal hearing subjects participated. Results indicate that MCL shift can be used as a simple measure of speech attenuation provided by HPDs. The observed MCL shifts were affected by the fitting instruction but not by the listening condition. Findings support the notion that MCL-based tests of speech attenuation by HPDs can be conducted reliably both in sound field and under earphones and may be a simple and valid tool for assessing changes in speech audibility due to the wearing of HPDs.

Leukocyte-depleting effect of hypothermia on muscle flap microcirculation following ischemia-reperfusion injury.

The aim of this study was to determine the effect of leukocyte-endothelial interaction and capillary perfusion on the microcirculation of muscle flaps submitted to ischemia in normothermic and hypothermic conditions. The cremaster muscle flap model was employed. Sixty rats were studied in six groups: normothermic and hypothermic control groups and groups that underwent reperfusion after 4 and 6 hours of ischemia in both normothermic and hypothermic conditions. In each group the following measurements were made: main vessel diameters, red blood cell velocities, the number of perfused capillaries, and the number of leukocytes rolling and sticking in the postcapillary venules. Hypothermia decreased the flow rate significantly and eliminated leukocytes from the microcirculation. Six hours of ischemia under normothermic conditions proved to be lethal for these muscle flaps, whereas hypothermia preserved flap viability.

Brachial plexus neuropathies after advanced laparoscopic surgery.

A retrospective review of 3,200 advanced laparoscopic procedures demonstrated five brachial plexus injuries during a 5-month period in 1986 (0.16% incidence rate). Brachial plexus injury can occur during laparoscopic surgery using steep Trendelenburg's position with shoulder braces and the patient's arm extended at 90 degrees. Position modification can reduce the risk for upper extremity neuropathies.