Plunging when drilling: effect of using blunt drill bits.

OBJECTIVE: : Plunging when drilling can be a detrimental factor in patient care. There is, although, a general lack of information regarding the surgeon's performance in this skill. The aim of this study was to determine the effect that using sharp or blunt instruments had on the drill bit's soft tissue penetration, using a simulator. MATERIALS AND METHODS: : Surgeons taking part in an International Trauma Course were invited to participate. Two groups were defined: experienced and inexperienced surgeons. Twelve holes were drilled in the following order: 3 holes with a sharp drill bit in normal bone (SNB), 3 holes with a sharp drill bit in osteoporotic bone (SOB), 3 holes with a blunt drill bit in normal bone, and 3 holes with a blunt drill bit in osteoporotic bone. Mean values and Student t tests were used for statistical analysis. RESULTS: : Thirty-seven surgeons participated, 20 experienced and 17 inexperienced surgeons. Mean plunging depths for SNB, SOB, blunt drill bit in normal bone, and blunt drill bit in osteoporotic bone were, respectively, 5.1, 5.4, 21.1, and 13.9 mm for experienced surgeons and 7.6, 7.7, 22, and 15.9 mm for inexperienced surgeons. Drilling with SNB and with SOB was statistically different, with inexperienced surgeons plunging 2.5 mm (P = 0.31) and 2.6 mm (P = 0.042) deeper, respectively. There was a difference (P < 0.001) between sharp and blunt drill bits in all drilling conditions for both the groups. CONCLUSIONS: : Our study showed a significant difference in plunging depth when sharp or bunt drill bit was being used. Surgeons, regardless of their experience level, penetrate over 20 mm in normal bone and over 10 mm in osteoporotic bone.

Expression of pSTAT5 predicts FLT3 internal tandem duplications in acute myeloid leukemia.

Mutations of the Fms-like tyrosine kinase 3 (FLT3) can be detected in a significant number of acute myeloid leukemias (AML). Seventy-five cases of acute myeloid leukemia were evaluated for FLT3-internal tandem duplications (ITD) by polymerase chain reaction. Paraffin-embedded formalin-fixed trephine biopsies of these cases were evaluated for expression of phosphorylated signal transducer and activator of transcription 1 (pSTAT1), pSTAT3, and pSTAT5. Specific expression of pSTAT5 was proven in leukemic blasts in situ by double staining with a blast-specific marker. Expression of pSTAT5 in > or =1% of blasts was highly predictive of FLT3-ITD. Neither expression of pSTAT1 nor pSTAT3 were associated with FLT3 mutations. Altogether we conclude that pSTAT5 expression can precisely be assessed by immunohistochemistry in routinely processed bone marrow trephines, STAT5 is highly likely the preferred second messenger of FLT3-mediated signaling in AML, and expression of pSTAT5 is predictive of FLT3-ITD.

Computer-assisted placement technique in hip resurfacing arthroplasty: improvement in accuracy?

Freehand positioning of the femoral drill guide is difficult during hip resurfacing and the surgeon is often unsure of the implant position achieved peroperatively. The purpose of this study was to find out whether, by using a navigation system, acetabular and femoral component positioning could be made easier and more precise. Eighteen patients operated on by the same surgeon were matched by sex, age, BMI, diagnosis and ASA score (nine patients with computer assistance, nine with the regular ancillary). Pre-operative planning was done on standard AP and axial radiographs with CT scan views for the computer-assisted operations. The final position of implants was evaluated by the same radiographs for all patients. The follow-up was at least 1 year. No difference between both groups in terms of femoral component position was observed (p > 0.05). There was also no difference in femoral notching. A trend for a better cup position was observed for the navigated hips, especially for cup anteversion. There was no additional operating time for the navigated hips. Hip navigation for resurfacing surgery may allow improved visualisation and hip implant positioning, but its advantage probably will be more obvious with mini-incisions than with regular incision surgery.

Pliensbachian magnetostratigraphy: new data from Paris Basin (France)

Sampling of an industrial drill string from the northeastern Paris Basin (Montcornet, France) provides early Jurassic magnetostratigraphic data coupled with biochronological control. About 375 paleomagnetic samples were obtained from a 145 m thick series of Pliensbachian rocks. A composite demagnetization thermal up to 300 C and an alternating field up to 80 mT were used to separate the magnetic components. A low unblocking temperature component (<250degreesC) with an inclination of about 64 is interpreted as a present-day field overprint. The characteristic remanent component with both normal and reversed antipodal directions was isolated between 5 and 50 mT. Twenty-nine polarity intervals were recognized. Correlation of these new results from the Paris Basin with data from the Breggia Gorge section (Ticino, southern Alps, Switzerland), which is generally considered as the reference section for Pliensbachian magnetostratigraphy, reveals almost identical patterns of magnetic polarity reversals. However, the correlation implies significant paleontological age discrepancies. Revised age assignments of biostratigraphic data of Breggia as well as an objective evaluation of the uncertainties on zonal boundaries in both Breggia and Moncornet resolve the initial discrepancies between magnetostratigraphic correlations and biostratigraphic ages. Hence, the sequence of magnetic reversals is significantly strengthened and the age calibration is notably improved for the Pliensbachian, a stage for which sections combining adequate magnetic signal and biostratigraphic constraints are still very few. (C) 2002 Elsevier Science B.V. All rights reserved.

In situ RHAMM protein expression in acute myeloid leukemia blasts suggests poor overall survival.

Treatment options for patients with high-risk acute myeloid leukemia (AML) include high-dose chemotherapy regimens in combination with allogeneic hematopoietic stem cell transplantation, which takes advantage of the donor T-cell-mediated graft-versus-leukemia effect. Together with beneficial responses observed in assays targeted at leukemia-associated antigens (LAA), this encouraged research on cancer vaccines and adoptive cellular therapies in AML. The receptor for hyaluronic acid-mediated motility (RHAMM, CD168) was identified as one of the most promising LAA in AML. Thus far, little is known about in situ expression in leukemic bone marrow blasts or the prognostic role of RHAMM and its interaction partners in AML. We immunohistochemically analyzed the expression and prognostic significance of RHAMM on trephine bone marrow biopsies from 71 AML cases that had been evaluated for cytogenetics and presence of FLT3-internal tandem duplications and NPM1 mutations. Fifty-five patients (77%) were treated with curative intent, while 16 (23%) received the most appropriate supportive care. Twenty of 71 (28%) AML cases were considered RHAMM+. Receiver operating characteristic curves showed significant discriminatory power considering overall survival (OS) in AML patients treated curatively for RHAMM (p = 0.015). Multivariable analysis revealed that expression of RHAMM in >5% of leukemic blasts identifies a subgroup of curatively treated cases with adverse OS independent of failures to achieve complete remission. RHAMM not only represents a promising LAA with specific T-cell responses in AML but, if assessed in situ on blasts, also a probable prognostic factor.