Morphometric three-dimensional computed tomography anatomy of the hypoglossal canal

Optimal surgical exposure during the transcondylar approach may result in injury to the hypoglossal nerve. This study evaluated the utility of three-dimensional computed tomography (3-D CT) as a means of obtaining detailed anatomic information in an individual patient prior to surgery involving the hypoglossal canal. We studied 20 hypoglossal canals in ten patients using 3-D CT reconstructed from 1-mm CT slices. Detailed anatomic measurements were performed to define the relationship of the hypoglossal canal to the occipital condyles and clivus. The relationship of the hypoglossal canal to the occipital condyles and clivus were extremely variable. From the outer table of the clivus in the midline, the extracranial opening of the hypoglossal canal was 20.3 + 2.7 mm (range 15.7-24.7 mm). The intracranial opening was 7.4 + 2.3 mm (range 6.2-11.5 mm) from the inner table of the clivus. From the superior aspect of the condyle, the inner opening was 11.0 + 1.4 mm (range 8.7-12.7 mm) and the outer opening was 19.1 + 2.4 mm (range 14.3-22.8 mm). From the lowest point of the condyle, the outer opening was 12.4 + 2.1 mm (range 9.1-15.6 mm). The posterior condylar emissary vein was 12.2 + 3.0 mm from the intracranial opening of the hypoglossal canal. Three-dimensional CT is a useful tool for assessing critical anatomic relationships and tailoring surgical approaches for individual patients. The amount of bone that can be safely removed without violating the hypoglossal canal can be determined preoperatively for each patient.     

Effects of testosterone administration on growth hormone pulse dynamics in human immunodeficiency virus-infected women

The effects of testosterone administration on the GH axis in androgen-deficient HIV-infected women are unknown. In this study, we determined the effects of transdermal testosterone administration on GH secretory dynamics and pulse characteristics in this population. GH-IGF-I parameters were determined in response to testosterone (4.1 mg/patch, twice a week; estimated delivery rate, 150 microg/d) vs. placebo over 6 months in 31 HIV-infected women. IGF-I increased significantly in the testosterone-treated compared with the placebo-treated patients [37 (-4, 73) vs. -30 (-98, 39) ng/ml, P = 0.01; 4.8 (-0.5, 9.6) vs. -3.9 (-12.8, 5.1) nmol/liter]. GH pulse frequency increased significantly in the testosterone-treated compared with the placebo-treated subjects [1.0 (1.0, 2.0) vs. 0.0 (-0.5, 1.5) peaks per 12 h, respectively; P = 0.02]. Before testosterone administration, overnight GH pulse amplitude was significantly related to IGF-I in univariate (r = 0.41, P = 0.03) and multivariate regression analysis; however, free testosterone, estradiol, and body mass index were not significantly correlated with baseline IGF-I. In contrast, after 6 months of treatment with testosterone, the change in IGF-I was significantly correlated to the change in free testosterone in univariate (r = 0.40, P = 0.04) and multivariate regression analysis. For each 1.0 pg/ml (3.5 pmol/liter) increase in free testosterone, IGF-I increased 19 ng/ml (2.5 nmol/liter), controlling for estradiol, body mass index, and GH pulse parameters (r(2) = 0.64). We demonstrate that IGF-I increases in response to physiologic, transdermal testosterone in HIV-infected women. The mechanism of this effect is unknown, but may involve a direct effect of testosterone on IGF-I, independent of changes in GH pulse dynamics.     

A genome scan for joint-specific hand osteoarthritis susceptibility: The Framingham Study

OBJECTIVE: Studies investigating hand osteoarthritis (OA) as a single entity have not shown strong linkage of the disease with any chromosomal sites. We undertook this study to test our hypothesis that phenotypes of hand OA may show stronger linkage than has been shown for overall hand OA. METHODS: We performed a factor analysis on measures of hand OA to determine patterns of disease. Using the joint regions identified by this analysis, we performed a genome-wide linkage analysis for OA susceptibility loci using 426 original cohort members and 790 offspring cohort members in 267 pedigrees. Radiographic OA features evaluated included the Kellgren/Lawrence score, osteophytes, and joint space narrowing. Prior to linkage analysis, standardized residuals were computed from regression analysis of each phenotype on age. This was performed separately for each sex and cohort. The variance component model (GeneHunter) was then applied to the normalized scores of the residuals of both sexes and cohorts. RESULTS: There was evidence suggestive of linkage (logarithm of odds [LOD] score >1.5) at 16 sites. Four of these sites had LOD scores >3.0. Two of these sites (identified in the full sample) included a linkage region for OA of the distal interphalangeal (DIP) joint on chromosome 7 (155 cM; LOD score 3.06) and a linkage region for OA of the first carpometacarpal (CMC) joint on chromosome 15 (81 cM; LOD score 6.25). The other 2 sites (identified in women) included a linkage region for OA of the DIP joint on chromosome 1 (202 cM; LOD score 3.03) and a linkage region for OA of the first CMC joint on chromosome 20 (4 cM; LOD score 3.74). CONCLUSION: These data suggest that several chromosomes contain hand OA susceptibility genes and that a joint-specific approach may be more rewarding than a global approach to the genetics of hand OA. Further investigation of these regions is warranted using finer maps and other populations.     

Intraoperative angiography to assess graft patency after minimally invasive coronary bypass

Background. Intraoperative angiography was performed to confirm graft patency immediately after minimally invasive coronary bypass operations.

Methods. In 26 patients who had internal mammary artery grafting, intraoperative coronary angiography was performed with a portable digital fluoroscope.

Results. High-resolution angiograms were obtained in all cases. Angiography documented vasospasm of the graft or native vessel in 9 patients (graft in 3, native in 2, graft and native in 4 others), which responded promptly to intracoronary vasodilators in all. Angiography identified technically unsuspected and clinically silent fixed stenoses (>50%) in 11 patients, attributable to graft kinking in 2, anastomotic obstruction in 6 (total occlusion in 4), and stenosis of the left anterior descending artery just distal to the anastomosis in three cases (total occlusion in one). In 9 of 11 patients, fixed stenoses were sufficiently severe to warrant intraoperative intervention by surgical revision (n = 5) or angioplasty via the graft (n = 4).

Conclusions. Intraoperative angiography after minimally invasive coronary artery bypass operations can immediately identify dynamic and fixed obstructions and facilitate their prompt treatment, thereby ensuring that each patient leaves the operating room with an optimal surgical result.     

Unipapillary kidney: A case report and literature review

The congenital variant of the unipapillary kidney is associated with an abnormal contralateral kidney and frequently with anomalies of other systems as well. An additional case is presented and a review of the literature is discussed.     

Evaluation of a nonconstrained total shoulder prosthesis

We reviewed the radiographs and medical records of 76 patients with 98 nonconstrained total shoulder prostheses: 68 were inserted for rheumatoid arthritis, 25 for osteoarthritis, and five for avascular necrosis. The radiographic follow-up averaged 36 months. Radiographic evidence of postoperative complications was noted in 37 (38%) of 98 shoulders: dislocation of the humeral head (six), upward migration of the humerus (24), loosening of the glenoid compartment (15), loosening of the humeral component (five), subsidence of the humeral component (seven), and heterotopic bone formation (six). Patients with a dislocated prosthesis had limitation of motion, poor function, and residual pain. No increase in pain was associated with proximal subluxation of the humerus. No correlations were found between any of the radiographic findings (the presence of radiolucent lines about the glenoid or humeral components, humeral subsidence, or ectopic ossification) and any of the clinical findings (pain relief, range of motion, motor power, or functional improvement).