Thoracic outlet syndrome: evaluation with CT

Diagnosis of the thoracic outlet syndrome is often difficult, particularly in patients without osseous abnormalities on plain radiographs. The radiographic and computed tomographic (CT) findings were reviewed from 27 patients with thoracic outlet syndrome and 21 normal subjects. The plain radiographs and CT scans were assessed by two independent observers without awareness of the clinical history. Fifteen patients with thoracic outlet syndrome had osseous abnormalities (anomalous cervical ribs; abnormally long, drooping C-7 transverse processes) identifiable on plain radiographs. CT did not provide further diagnostic information in the patients with abnormal radiographs. Eight of 12 patients (66%) with normal plain radiographs had abnormal findings on CT scans, consisting of impingement of the C-7 transverse process on the scalene triangle or anteromedial aspect of the middle scalene muscle. Only two of 21 control patients (9.5%) displayed this CT abnormality (P less than .01). CT may be useful in patients with symptoms suggestive of thoracic outlet syndrome and no osseous abnormalities on plain radiographs.     

Lipohemarthrosis of the knee: a review of recent experiences

The radiographs of 268 patients with knee trauma were retrospectively reviewed. In 15 patients with intraarticular fracture, the images demonstrated fat-fluid levels. In 28 other patients with intraarticular fracture, only joint effusion without a fat-fluid level was depicted. The presence of a fat-fluid level in the knee indicated fracture in all patients in whom it was seen. The absence of such a level, however, did not exclude intraarticular fracture.     

T2 values in the human brain: comparison with quantitative assays of iron and ferritin

Magnetic resonance (MR) imaging with a whole-body imager was performed in 10 fresh, unfixed whole human brains selected randomly from cadavers. All subjects were neurologically intact before death. T2 time constants were measured within the caudate nucleus, putamen, globus pallidus, cortical gray matter, subcortical white matter, and optic radiation. These regions were then excised, and T2 values were measured again with a 1.5-T MR spectrometer. Quantitative assays of iron, ferritin, and protein from these areas were then performed. Iron concentration varied significantly among brain regions, whereas ferritin and protein concentrations were constant among brain regions and among individuals. Neither iron nor ferritin concentration showed any consistent correlation with T2 values. Histologic examination of brain micro-sections with iron- and ferritin-specific stains of demonstrated poor correlation with biochemical assays of ferritin and iron concentrations. Results indicate that T2 values correlate poorly with iron and ferritin concentrations found in neurologically intact brains.     

A survey of robotic surgery training curricula in general surgery residency programs: How close are we to a standardized curriculum?

Background

Robotic surgery is increasingly adopted into surgical practice, but it remains unclear what level of robotic training general surgery residents receive. The purpose of our study was to assess the variation in robotic surgery training amongst general surgery residency programs in the United States.

Patellofemoral joint: kinematic MR imaging to assess tracking abnormalities

The patellofemoral joint was imaged with magnetic resonance (MR) in the axial plane while the knee was positioned from 0 degrees to 32 degrees of flexion (nine positions). These multiple sequential images obtained within the early phases of flexion of the knee were viewed in a "cine-loop" format, producing a kinematic study that clearly demonstrated the relationship of the patella to the trochlear groove. Four healthy subjects and one patient with known bilateral subluxing patellae were studied. The preliminary results suggest that kinematic MR imaging of the patellofemoral joint is potentially useful for the evaluation of patellar tracking abnormalities.     

A major internal initiation site for the in vitro translation of the adenovirus DNA polymerase

An open reading frame which encodes at least 90% of the adenovirus type 2 DNA polymerase gene was cloned behind the SP6 promoter and transcribed in vitro using the SP6 RNA polymerase. The resultant RNA was translated in a rabbit reticulocyte cell free system. In addition to the translation of a 120-kDa protein corresponding to the size of the complete open reading frame, the synthesis of a 62-kDa polypeptide was demonstrated. Data is presented to show that the synthesis of the 62-kDa polypeptide resulted from internal initiation of translation in frame in the middle of the message at the 11th or 12th AUG. Capping of the mRNA resulted in an increase in synthesis of the 120-kDa protein and a concordant decrease of the internally initiated polypeptide. We propose that there may be competition between the binding of the translational preinitiation complex at or near the 5' end of the mRNA and at the internal initiation site. Because of inhibition of synthesis of the 120-kDa but not the 62-kDa polypeptide by hybrid arrested translation using DNA complementary to approximately one third of the 5' Ad Pol mRNA sequences, scanning of the ribosome from the 5' end of the mRNA to the internal initiation site seemed unlikely. The sequence proximal to the 12th AUG is ACCCACCCCAUG which is similar to a noncontinuous sequence 5'AUCCACC(X)nAUG complementary to the 3' end of the 18 S rRNA. This sequence is a favored ribosome binding site based on the observation that it is the most commonly observed one at or near the 5' end of 162 mRNA's analyzed (D. R. Sargan, S. P. Gregory, and P. H. W. Butterworth, 1982, FEBS Lett. 147, 133-136).     

Comparison of revision strategies for failed C2-posterior cervical pedicle screws: a biomechanical study

Study purpose

With increasing usage within challenging biomechanical constructs, failures of C2 posterior cervical pedicle screws (C2-pCPSs) will occur. The purpose of the study was therefore to investigate the biomechanical characteristics of two revision techniques after the failure of C2-pCPSs.

Materials and methods

Twelve human C2 vertebrae were tested in vitro in a biomechanical study to compare two strategies for revision screws after failure of C2-pCPSs. C2 pedicles were instrumented using unicortical 3.5-mm CPS bilaterally (Synapse/Synthes, Switzerland). Insertion accuracy was verified by fluoroscopy. C2 vertebrae were potted and fixed in an electromechanical testing machine with the screw axis coaxial to the pullout direction. Pullout testing was conducted with load and displacement data taken continuously. The peak load to failure was measured in newtons (N) and is reported as the pullout resistance (POR). After pullout, two revision strategies were tested in each vertebra. In Group-1, revision was performed with 4.0-mm C2-pCPSs. In Group-2, revision was performed with C2-pedicle bone-plastic combined with the use of a 4-mm C2-pCPSs. For the statistical analysis, the POR between screws was compared using absolute values (N) and the POR of the revision techniques normalized to that of the primary procedures (%).

Results

The POR of primary 3.5-mm CPSs was 1,140.5 ± 539.6 N for Group-1 and 1,007.7 ± 362.5 N for Group-2; the difference was not significant. In the revision setting, the POR in Group-1 was 705.8 ± 449.1 N, representing a reduction of 38.1 ± 32.9 % compared with that of primary screw fixation. For Group-2, the POR was 875.3 ± 367.9 N, representing a reduction of 13.1 ± 23.4 %. A statistical analysis showed a significantly higher POR for Group-2 compared with Group-1 (p = 0.02). Although the statistics showed a significantly reduced POR for both revision strategies compared with primary fixation (p < 0.001/p = 0.001), the loss of POR (in %) in Group-1 was significantly higher compared with the loss in Group-2 (p = 0.04).

Conclusions

Using a larger-diameter screw combined with the application of a pedicle bone-plastic, the POR can be significantly increased compared with the use of only an increased screw diameter.     

Transplantation of Haploidentical TcRaß‐Depleted Hematopoietic Cells Allows for Optimal Timing and Sustained Correction of the Metabolic Defect in Children With Infantile Osteopetrosis

In osteopetrosis, osteoclast dysfunction can lead to deafness, blindness, bone marrow failure, and death. Hematopoietic cell transplantation (HCT) is currently the only curative treatment, but outcome remains disappointing. Although a rapid progression toward HCT is detrimental to prevent further progress of disease manifestations, 70% of cases lack an HLA‐matched sibling and require alternative stem cell sources. We present two cases of osteopetrosis that successfully received an HCT with haploidentical TcRαβ‐depleted cells from one of the parents. These cases showed no further disease progression, had restoration of functional osteoclasts, and illustrate this approach to enable prompt HCT with ready available parental donors and rapid and sustained hematological, including osteoclast, recovery. © 2016 American Society for Bone and Mineral Research.