Reaming versus non-reaming in medullary nailing: Interference with cortical circulation of the canine tibia

Summary Medullary nails have only been used with reluctance in the treatment of open fractures since reaming interferes with the cortical circulation. The technique of interlocking offers the interesting possibility of inserting a relatively stiff nail which does not necessarily require reaming. The effects of reaming prior to nail insertion upon the cortical circulation was investigated in the canine tibia. Intravital staining with procion red was used to trace areas of disturbed circulation. Nail insertion without reaming provided clear advantages for the bone's blood supply, while reaming disturbed perfusion in two-thirds of the cortical area and regionally extended through the entire thickness of the cortex. The disturbance without reaming was limited to the inner layer of the cortex and involved only one-third of the cortical cross-section.     

Treatment of defects of the long bones using distraction osteogenesis (Ilizarov) and intramedullary nailing. Theoretic principles, animal experiments, clinical relevance

For large shaft defects of tibia and femur, distraction-compression osteosynthesis (Ilizarov) provides an ideal autologous bone graft. Combination of this with an intramedullary interlocking nail instead of an external fixator could improve patient comfort, because transport with a small external device takes only one-third of the total fixation period. Using 21 adult female sheep we created standardized tibia shaft defects 20 mm (medium size) and 45 mm (large size) in length. The tibiae were stabilized with non-reamed intramedullary interlocking nails. Following corticotomy by chisel, segments were transported using subcutaneous traction wires with a screw as a fulcrum to maintain stationary skin exit points without soft tissue problems. The external traction devices were removed after 12 or 16 weeks. Animals were sacrificed after 12 or 24 weeks with medium-size defects, and after 16 or 32 weeks with large defects. We evaluated the results clinically, by standardized weekly X-rays and, after sacrifice, by quantitative computed tomography (QCT). No animals had to be excluded from the study. Despite primary destruction of the intramedullary circulation all distraction gaps were spanned with bone. X-Rays showed typical signs of good quality of distraction bone regeneration (narrow radiolucent zone in the middle of the regenerate, longitudinal structure), continuous calcification, and cortex formation. QCT cross sections showed completely circular bone regeneration with small and large defects. Bone regeneration was faster on the dorsal side, where more bone was formed than ventrally. Small defects can remain ventrally in the regenerate; these close secondarily.(ABSTRACT TRUNCATED AT 250 WORDS)     

Perforated colorectal neoplasms: correlation of clinical, contrast enema, and CT examinations

Results of clinical, contrast enema (CE), and computed tomographic (CT) examinations in 39 patients with perforated colorectal neoplasms were retrospectively reviewed. Twenty patients were toxemic at initial presentation, but in only four patients was the diagnosis of perforated colorectal neoplasm initially suspected clinically. CE study was performed in 22 patients and enabled the diagnosis of perforated neoplasm in 11 cases, neoplasm alone in eight, and neither neoplasm nor perforation in three. CT was performed in 38 patients and enabled the diagnosis of perforated neoplasm in 36; pericolic phlegmon but no mass lesion was evident in two. In 16 patients, CT also demonstrated metastatic disease. Because of its reliability in establishing the diagnosis and staging the extent of the inflammatory and neoplastic disease, CT is indicated in cases of suspected or proved perforated colorectal neoplasm and in cases in which CE study findings are indeterminate or suggestive of perforated neoplasm.     

Frequent ongoing T-cell receptor rearrangements in childhood B- precursor acute lymphoblastic leukemia: implications for monitoring minimal residual disease

Crosslineage T-cell receptor delta (TCR delta) rearrangements are widely used as tumor markers for the follow up of minimal residual disease in childhood B-precursor acute lymphoblastic leukemia (ALL) by polymerase chain reaction (PCR). The major drawback of this approach is the risk of false-negative results due to clonal evolution. We investigated the stability of V delta 2D delta 3 rearrangements in a group of 56 childhood B-precursor ALL patients by PCR and Southern blot analysis. At the PCR level, V delta 2D delta 3-to-J alpha rearranged subclones (one pathway for secondary TCR delta recombination) were demonstrated in 85.2% of V delta 2D delta 3-positive patients tested, which showed that small subclones are present in the large majority of patients despite apparently monoclonal TCR delta Southern blot patterns. Sequence analysis of V delta 2D delta 3J alpha rearrangements showed a biased J alpha gene usage, with HAPO5 and J alpha F in 26 of 32 and 6 of 32 clones, respectively. Comparison of V delta 2D delta 3 rearrangement status between diagnosis and first relapse showed differences in seven of eight patients studied. In contrast, from first relapse onward, no clonal changes were observed in six patients studied. To investigate the occurrence of crosslineage TCR delta rearrangements in normal B and T cells, fluorescence-activated cell sorter-sorted peripheral blood CD19+/CD3- and CD19-/CD3+ cell populations from three healthy donors were analyzed. V delta 2D delta 3 rearrangements were detected at low frequencies in both B and T cells, which suggests that V delta 2-to-D delta 3 joining also occurs during normal B-cell differentiation. A model for crosslineage TCR delta rearrangements in B-precursor ALL is deduced that explains the observed clonal changes between diagnosis and relapse and is compatible with multistep leukemogenesis of B-precursor ALL.     

Lyme disease: recommendations for diagnosis and treatment

The incidence and the endemic range of Lyme disease in the United States have increased steadily since the disease was originally recognized in Lyme, Connecticut, in 1975. Because of the varied clinical manifestations of this illness and the use of unstandardized serologic testing methods, diagnosis is often uncertain and treatment outcomes are often difficult to evaluate. The antibiotic regimens that are commonly used in clinical practice have changed rapidly. They show much regional variation with little critical comparison of treatment results. The clinical diagnosis and the literature on the treatment of the various stages of Lyme disease are reviewed. The reported data are supplemented with recommendations based on 15 years of clinical experience with this illness.     

Induction of monocyte chemotaxis in devascularized rabbit bone

Summary Temporary impairment of blood supply has been suggested to cause bone remodeling. The degradation of cells and matrix and the attraction of resorbing cells were examined in this study. Bone specimens of rabbits were stored in vitro for 2–20 days. At the end of this aging process the probes were tested for their chemotactic activity toward autologous leukocytes in a diffusion chamber. Both supernatant from the aged bone specimens and ground bone particles exhibited significant chemotactic activity that was specifically attracting monocytes. It is suggested that soluble bone matrix proteins or degeneration products liberated during ischemic damage to cortical bone initiate the resorptive process.This work was supported by the Swiss National Science Foundation, grant no. 3.857.0.83, and by the Studienstiftung des deutschen Volkes