Biomechanical Comparison of Inter-fragmentary Compression Pressures: Lag Screw versus Herbert Screw for Anterior Odontoid Screw Fixation

OBJECTIVE: The purpose of the present study was to compare inter-fragmentary compression pressures after fixation of a simulated type II odontoid fracture with the headless compression Herbert screw and a half threaded cannulated lag screw. METHODS: We compared inter-fragmentary compression pressures between 40- and 45-mm long 4.5-mm Herbert screws (n=8 and n=9, respectively) and 40- and 45-mm long 4.0-mm cannulated lag screws (n=7 and n=10, respectively) after insertion into rigid polyurethane foam test blocks (Sawbones, Vashon, WA, USA). A washer load cell was placed between the two segments of test blocks to measure the compression force. Because the total length of each foam block was 42 mm, the 40-mm screws were embedded in the cancellous foam, while the 45-mm screws penetrated the denser cortical foam at the bottom. This enabled us to compare inter-fragmentary compression pressures as they are affected by the penetration of the apical dens tip by the screws. RESULTS: The mean compression pressures of the 40- and 45-mm long cannulated lag screws were 50.48±1.20 N and 53.88±1.02 N, respectively, which was not statistically significant (p=0.0551). The mean compression pressures of the 40-mm long Herbert screw was 52.82±2.17 N, and was not statistically significant compared with the 40-mm long cannulated lag screw (p=0.3679). However, 45-mm Herbert screw had significantly higher mean compression pressure (60.68±2.03 N) than both the 45-mm cannulated lag screw and the 40-mm Herbert screw (p=0.0049 and p=0.0246, respectively). CONCLUSION: Our results showed that inter-fragmentary compression pressures of the Herbert screw were significantly increased when the screw tip penetrated the opposite dens cortical foam. This can support the generally recommended surgical technique that, in order to facilitate maximal reduction of the fracture gap using anterior odontoid screws, it is essential to penetrate the apical dens tip with the screw.

Molecular Cytogenetic Analysis of Gene Rearrangements in Childhood Acute Lymphoblastic Leukemia

The aims of this study were to estimate the incidences of BCR/ABL, MLL, TEL/AML1 rearrangements, and p16 deletions in childhood acute lymphoblastic leukemia (ALL), to identify new abnormalities, and to demonstrate the usefulness of interphase fluorescence in situ hybridization (FISH). We performed G-banding analysis and FISH using probes for BCR/ABL, MLL, TEL/AML1 rearrangements, and p16 deletions on 65 childhood ALL patients diagnosed and uniformly treated at a single hospital. Gene rearrangements were identified in 73.8% of the patients using the combination of G-banding and FISH, while the chromosomal abnormalities were identified in 49.2% using G-banding alone. Gene rearrangements were disclosed by FISH in 24 (72.7%) of 33 patients with normal karyotype or no mitotic cell in G-banding. Among the gene rearrangements detected by FISH, the most common gene rearrangement was p16 deletion (20.3%) and the incidences of others were 14.1% for TEL/AML1, 11.3% for MLL, and 1.8% for BCR/ABL translocations. Infrequent or new aberrations such as AML1 amplification, MLL deletion, ABL deletion, and TEL/AML1 fusion with AML1 deletion were also observed. We established the rough incidences of gene rearrangements in childhood ALL, found new abnormalities and demonstrated the diagnostic capability of interphase FISH to identify cryptic chromosome aberrations.

Correlation between Progenitor Cell Dose and the Rate of Engraftment in Autologous Peripheral Blood Stem Cell Transplantation and Allogeneic Bone Marrow Transplantation / 대한수혈학회지

BACKGROUND: Bone marrow transplantation (BMT) or peripheral blood stem cell transplantation (PBSCT) following high dose chemotherapy has been an important therapeutic option for patients with hematologic malignancies or some solid tumors. The number of progenitor cells in the collection products has been used to determine the optimum time to stop the collections and to predict the hematopoietic engraftment after transplantation. In this study, we investigated the relationship between end-product cell counts measured by different methods and the influence of the infused cell dose on the engraftment rate. METHODS: Twenty five patients receiving autologous PBSCT and 25 patients receiving allogeneic BMT were studied. The number of total nucleated cells (TNC), of mononuclear cells (MNC), of CD34+ cells, and of CFU-GM (colony-forming unit-granulocyte monocyte) colonies were measured in each collection product. The number of days required to achieve an absolute neutrophil count (ANC) of 0.5x109/L with TNC count of 1.0x109/L and platelet count of 20x109/L without transfusions was taken as an arbitrary measure of the engraftment rate. RESLUTS: A close correlation between CD34+ cells/kg and CFU-GM/kg was observed in both collection products (p<0.05). However, MNC/kg also showed significant correlations with CD34+ cells/kg and CFU-GM/kg in allogeneic bone marrow collection products (p<0.05). The CFU-GM amount in the PBSC products was greater than that in the bone marrow collection products (p<0.05). Time to engraftment was a median of 14 (range 9-50) days in autologous PBSCT group, but 29 (range 17-57) days in allogeneic BMT group. In autologous PBSCT, infused CD34+ cells/kg and CFU-GM/kg correlated significantly with ANC recovery (p<0.05). CONCLUSIONS: The number of CD34+ cells was correlated with that of CFU-GM in the collection products, and the infused cell doses showed positive relation to the engraftment rate in autologous PBSCT. These findings suggest that measurement of CD34+ cell counts alone would be a sufficient parameter to predict the engraftment rate in autologous PBSCT.

Induction Chemotherapy with BH-AC, Idarubicin, and 6-Thioguanine in Childhood Acute Myelogenous Leukemia

PURPOSE: We have undertaken this study to evaluate the effects of induction chemotherapy involving BH-AC, idarubicin, and 6-thioguanine (6-TG). METHODS: BH-AC 300mg/m2/day was administered intravenously over three hours for seven consecutive days. Idarubicin 12mg/m2/day was administered intravenously for three days. 6-TG 100 mg/m2/day was administered orally for seven days. Intrathecal ara-C was administered on the first day of treatment. RESULTS: Complete remission (CR) was achieved in 18 cases (66.7%), partial remission (PR) was achieved in 2 cases (7.4%). In previously untreated patients, complete reimission rate was 92.9% (13/ 14), in relapsed patients, 40% (2/5) and in the refractory patients, 37.5% (3/8). The remission duration until December 1996 was 45 to 630 days (median 133). Duration of the neutropenia (ANC<500/microliter) was 0 to 38 days (median 24). Side effects were nausea, vomiting (7/27, 25.9%), liver dysfunction (1/27, 3.7%), skin eruption (1/27, 3.7%), and mucositis (1/27, 3.7%). In all cases, fever developed in the neutropenic state (culture proven sepsis in 5 cases). Death occurred in 5 cases who achieved CR due to sepsis after chemotherapy (4 cases), intracerebral hemorrhage after bone marrow relapse (1 case). CONCLUSION: BH-AC, idarubicin, and 6-TG induction chemotherapy could be a useful induction chemotherapy treatment that combines supportive care for infection and bleeding.

Outcome after Treatment of Retinoblastoma

PURPOSE: Current treatment in retinoblastoma aims to save life and preserve useful vision by using combined modality therapy. This study was performed to determine the outcome after treatment of retinoblastoma. METHODS: Medical records of all cases of retinoblastoma seen at Seoul National University Children's Hospital from September 1986 to April 1995 were reviewed. During this period, the treatment method was consistent for the patients with retinoblastoma as follows; for intraocular disease with visual potential, nonsurgical treatment consisted of radiation therapy and/or light coagulation, cryotherapy was considered, followed by enucleation if there was no response, and for intraocular disease without visual potential and extraocular disease, enucleation of those eyes that had severe involvement followed by radiation therapy and/or chemotherapy (systemic or intrathecal) was done according to the clinical pathologic staging. RESULTS: In 58 patients, 6 patients died and the 3-year survival rate was 83%. There was no difference in survival rate between 47 unilateral and 11 bilateral cases, which were 80% and 91%, respectively (P=0.790). The survival rate of 74% for 16 extraocular disease was lower than that of 87% for 42 intraocular disease and the difference of the survival rate between these two groups has shown borderline statistical significance (P=0.056). The 3-year event free survival rate was 69% in overall patients. Complications following therapy included infection due to bone marrow suppression, cardiomyopathy, and orbital contracture. One case of osteosarcoma has developed as a second malignant neoplasm. CONCLUSIONS: To improve the survival of retinoblastoma, effective therapy for extraocular disease and prevention of extraocular extension are important. Supportive care to minimize the complications of therapy and long-term follow-up for second malignant neoplasm are also needed.