Biomedical subjects

Kamal Ibrahim

Publications and source records attributed to Kamal Ibrahim.

3 recordsLinked to original sources

PubMed2006

Comparison of the lowest instrumented, stable, and lower end vertebrae in "single overhang" thoracic adolescent idiopathic scoliosis: anterior versus posterior spinal fusion.

STUDY DESIGN: A retrospective multicenter study. OBJECTIVE: To investigate the relationship between the lowest instrumented, stable, and lower end vertebrae in patients with "single overhang" thoracic (main thoracic) curves treated with anterior or posterior spinal fusion. SUMMARY OF BACKGROUND DATA: Previous studies have shown "saving" fusion levels with anterior spinal fusion, as opposed to posterior spinal fusion; however, to our knowledge, none of these studies evaluated the relative position to the lower end vertebra to compare study groups accurately. For clarification, "single overhang" includes Lenke 1A and 1B curves. For these thoracic curves, the lumbar curve does not cross the midline. MATERIALS AND METHODS: A retrospective multicenter study of adolescent idiopathic scoliosis was performed to identify specifically patients with "single overhang" thoracic (Lenke 1A and 1B) curves with more than a 2-year follow-up. To analyze relative fusion levels, the differences were computed as follows: (1) the difference between the vertebra position for the stable vertebra of the main thoracic (MT) curve and the lowest instrumented vertebra, as noted on postoperative radiographs, or [equation: see text] (2) the difference between the vertebra position for the lower end vertebra of the main thoracic (MT) curve and the lowest instrumented vertebra, as noted on postoperative radiographs, or [equation: see text]. RESULTS: A total of 298 "single overhang" thoracic curves (148 Lenke 1A, 150 Lenke 1B) were identified, of which 293 had either an anterior spinal fusion or posterior spinal fusion; 5 patients underwent a combined anterior-posterior spinal fusion. Anterior spinal fusion was performed in 70 patients (23.9%) and posterior spinal fusion in 223 (76.1%). While comparing the lowest instrumented vertebra to the stable vertebra with anterior spinal fusion, the lowest instrumented vertebra was identified either at the level of the stable vertebra or above in 97% of 1A/B curves (P < 0.001). Using posterior spinal fusion techniques, the lowest instrumented vertebra was identified either at the stable vertebra or above in 65% of the 1A/B curves (P < 0.05). CONCLUSIONS: These data confirm that anterior spinal fusion techniques result in a mean shorter fusion of 1.5 vertebral segments/patient when compared to posterior spinal fusion techniques with respect to the position of the lowest instrumented and stable vertebrae for "single overhang" thoracic (Lenke 1A/B) curves. However, because this is a retrospective multicenter study over 10 years, it represents various posterior spinal fusion techniques that do not include all pedicle screw constructs.

Adolescent↗

PubMed2002

A reliable and accurate method for measuring orthosis wearing time.

STUDY DESIGN: Compliance monitor measurement of orthosis wearing time during laboratory climate tests and normal volunteer subject tests were compared to normal diaries. OBJECTIVE: To develop and test the accuracy and reliability of a device designed to measure spinal orthosis wearing time. SUMMARY OF BACKGROUND DATA: Orthosis wearing time is an important factor in orthotic treatment for spine disorders. A reliable and objective method for measuring orthosis wearing time currently is lacking. METHODS: Four pressure switches and a data logger embedded in each thoracolumbosacral orthosis recorded orthosis wearing time. Orthoses were assumed to be worn when at least two switches were "on." Laboratory climate tests and normal volunteer tests were conducted to assess the ability of the compliance monitor to measure orthosis wearing time. A manual wearing-event diary was kept during all the tests. The length of each wearing-time interval, the daily wearing time, and the cumulative wearing time were calculated from data recorded by the compliance monitor and the manual diaries. RESULTS: A linear regression was performed on all orthosis wearing-time intervals as recorded by the compliance monitor and by the manual diaries. Climate chamber tests yielded 121 sensor trigger-event intervals (R2 = 0.998; slope = 1.003; P < 0.0001). Normal subject testing yielded 72 orthosis wearing-time intervals (R2 = 0.998; slope = 0.998; P < 0.0001). CONCLUSION: As indicated by the regression analyses, the compliance monitor accurately quantified the orthosis wearing-time intervals during the laboratory climate tests and the tests with normal volunteers.

Braces↗

PubMed2002

Prothrombin activation in eastern tiger snake bite.

AIMS: To perform ex vivo studies in eastern tiger snake envenomation which define the haemostatic events associated with prothrombin activation. METHOD: Serial studies were performed on plasma from six individuals with evidence of eastern tiger snake envenomation. These analyses were particularly directed to fibrinogen levels, F1 + 2, TAT and evidence of fibrinolysis. RESULTS: There was a substantial rise in F1 + 2 and thrombin-antithrombin (TAT) complexes in all cases, even with minimal evenomation. In some cases the molar ratio of F1 + 2 and TAT was reduced from the relationship normally seen in vitro and ex vivo in clinical thrombosis. There was a dramatic fall in factor V and VIII levels which occurred 4-6 hours before the decline in prothrombin and AT3. This related in time to a fall in alpha2AP and plasminogen. Protein C levels also declined dramatically but many hours after presentation. CONCLUSIONS: F1 + 2 and TAT are sensitive markers of tiger snake evenomation. In some patients with massive prothrombin activation, the common mechanism for TAT clearance may be altered or overwhelmed. Conversely, the renal clearance of the smaller F1 + 2 may be enhanced. In the absence of thrombocytopaenia, which is a very sensitive marker of DIC, the fall in labile factors with tiger snake envenomation is significantly contributed to by proteolytic digestion of clotting factors.

Adolescent↗