Publications by authors named "Troy Patience"

3 Publications

  • Page 1 of 1

Fetal growth curves for an ethnically diverse military population: the American Institute of Ultrasound in Medicine-accredited platform experience.

Mil Med 2006 Jun;171(6):508-11

Department of Obstetrics and Gynecology, Tripler Army Medical Center, Honolulu, HI 96859-5000, USA.

Objective: To determine which fetal growth curve provided the best estimates of fetal weight for a cohort of ethnically diverse patients at sea level.

Methods: The study consisted of a population of 1,729 fetuses examined at sea level between January 1, 1997, and June 30, 2000, at 18 weeks, 28 weeks, and term. Gestational age (GA) based on menstrual dates was confirmed or adjusted by crown-rump length or early second-trimester biometry. Fetal weight was estimated by using biparietal diameter, head circumference, abdominal circumference, and femur length. Our fetal growth curves were analyzed with fourth-order polynomial regression analysis, applying four previously defined formulae for fetal growth.

Results: Fetal growth curves for estimated fetal weight demonstrated the expected parabolic shape, which varied according to the formulae used. Our curve best fit the following equation: estimated fetal weight = 4.522 - 0.22 x GA age + 0.25 x GA(2) - 0.001 x GA(3) + 5.248 x 10(-6) x GA(4) (R2 = 0.976). SD increased in concordance with GA.

Conclusion: Madigan Army Medical Center serves a racially mixed, culturally diverse, military community with unrestricted access to prenatal care. Determination of the optimal population-appropriate growth curve at the correct GA assists clinicians in identifying fetuses at risk for growth restriction or macrosomia and therefore at risk for increased perinatal morbidity and death.
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http://dx.doi.org/10.7205/milmed.171.6.508DOI Listing
June 2006

Effects of pilot hole preparation technique on pedicle screw fixation in different regions of the osteoporotic thoracic and lumbar spine.

J Neurosurg Spine 2005 Nov;3(5):364-70

Department of Orthopaedic Surgery, Spine Division, The University of Rochester School of Medicine and Dentistry, Rochester, New York, USA.

Object: The authors evaluated the effects of pilot hole preparation technique on insertional torque and axial pullout resistance in osteoporotic thoracic and lumbar vertebrae.

Methods: Using a probe technique and fluoroscopy, 102 pedicle screws were placed in 51 dual-energy x-ray absorptiometry-proven osteoporotic thoracic and lumbar levels. Screws were inserted using the same-size tapping, one-size-under tapping, or no-tapping technique. Insertional torque and axial pullout resistance were measured. Analysis of variance, Fisher exact test, and regression analysis were performed. Same-size tapping decreased pullout resistance in the lumbar spine. There was no effect on pullout resistance in the thoracic spine. Pullout resistance values were lower for all insertion techniques in the upper thoracic spine. Insertional torque and bone mineral density correlated with pullout resistance in the thoracic and lumbar spine.

Conclusions: Tapping decreased pedicle screw pullout resistance in the osteoporotic human lumbar spine, although it did not affect pullout strength in the thoracic spine. Tapping decreased insertional torque in upper thoracic levels. Surgeons should optimize overall construct rigidity when placing thoracic pedicle screws in patients with spinal segment osteoporosis.
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http://dx.doi.org/10.3171/spi.2005.3.5.0364DOI Listing
November 2005

Maternal ethnicity and variation of fetal femur length calculations when screening for Down syndrome.

J Ultrasound Med 2002 Jul;21(7):719-22; quiz 724-5

Department of Obstetrics and Gynecology, Madigan Army Medical Center, Tacoma, Washington 98431, USA.

Objective: To determine whether current methods for detecting Down syndrome based on fetal femur length calculations are influenced by ethnicity.

Methods: The study population consisted of all fetuses scanned between 14 and 20 completed weeks' gestation from April 1, 1997, to January 1, 2000. The expected femur length was calculated from the biparietal diameter. The variance from the expected femur length, compared with the biparietal diameter, was calculated, and the mean variations were compared by maternal race. Ethnic-specific formulas for expected femur length were derived by simple regression.

Results: There was a statistically significant difference in femur length in the Asian group compared with all other groups, as well as the white group compared with the black and Asian groups (P < .05). However, there was no significant difference between the black and Hispanic groups or the white and Hispanic groups. The Asian group had the largest variation, with the measured femur length being less than the expected femur length. All groups studied had a mean expected femur length less than the mean measured femur length. On the basis of the ethnic-specific formulas for femur length, there was a significant decrease in patients that would undergo further evaluation for Down syndrome.

Conclusions: There is a significant difference in the mean expected femur length by biparietal diameter among fetuses in the second trimester with regard to ethnicity. Using ethnic-specific formulas for expected femur length can have a considerable impact on the use of sonographic risk factors for Down syndrome screening. Further data are required for use of femur length as a screening tool in the genetic sonogram.
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http://dx.doi.org/10.7863/jum.2002.21.7.719DOI Listing
July 2002