Intracompartmental pressure measurements are frequently used in the diagnosis of compartment synd... more Intracompartmental pressure measurements are frequently used in the diagnosis of compartment syndrome, particularly in patients with equivocal or limited physical examination findings. Little clinical work has been done to validate the clinical use of intracompartmental pressures or identify associated false-positive rates. We hypothesized that diagnosis of compartment syndrome based on one-time pressure measurements alone is associated with a high false-positive rate. Forty-eight consecutive patients with tibial shaft fractures who were not suspected of having compartment syndrome based on physical examinations were prospectively enrolled. Pressure measurements were obtained in all four compartments at a single point in time immediately after induction of anesthesia using a pressure-monitoring device. Preoperative and intraoperative blood pressure measurements were recorded. The same standardized examination was performed by the attending surgeon preoperatively, postoperatively, and during clinical follow-up for 6 months to assess clinical evidence of acute or late compartment syndrome. No clinical evidence of compartment syndrome was observed postoperatively or during follow-up until 6 months after injury. Using the accepted criteria of delta P of 30 mm Hg from preoperative diastolic blood pressure, 35% of cases (n = 16; 95% confidence interval, 21.5-48.5%) met criteria for compartment syndrome. Raising the threshold to delta P of 20 mm Hg reduced the false-positive rate to 24% (n = 11; 95% confidence interval, 11.1-34.9%). Twenty-two percent (n = 10; 95% confidence interval, 9.5-32.5%) exceeded absolute pressure of 45 mm Hg. A 35% false-positive rate was found for the diagnosis of compartment syndrome in patients with tibial shaft fractures who were not thought to have compartment syndrome by using currently accepted criteria for diagnosis based solely on one-time compartment pressure measurements. Our data suggest that reliance on one-time intracompartmental pressure measurements can overestimate the rate of compartment syndrome and raise concern regarding unnecessary fasciotomies. Diagnostic study, level II.
Minimally invasive osteosynthesis of proximal tibial fractures has grown in popularity in recent ... more Minimally invasive osteosynthesis of proximal tibial fractures has grown in popularity in recent years. This article describes a patient with a Schatzker type VI proximal tibial fracture (AO/OTA type 41.C3) and previous compartment syndrome treated with definitive fixation 8 weeks after initial injury with a precontoured proximal tibial plate and a distal targeting device. Brisk bleeding occurred during percutaneous insertion of a cortical screw at the midshaft of the tibia. Surgical exploration revealed sidewall tearing of the anterior tibial artery and vein, which were clipped at the screw insertion site. After the bleeding was controlled, the patient had a strong palpable posterior tibial pulse with no palpable dorsalis pedis pulse, and the foot remained well perfused. Function of the deep peroneal nerve was normal postoperatively. Previous concerns regarding the percutaneous treatment of proximal tibial fractures have focused on the risks of damage to the superficial peroneal ne...
We assessed whether, in contrast to reports in the literature, computed tomographic (CT) scans im... more We assessed whether, in contrast to reports in the literature, computed tomographic (CT) scans improve the ability to classify acetabular fractures in comparison with plain radiographs. Prospective. Level I trauma center. Seventy-five patients with 75 acetabular fractures treated between June 2005 and May 2006. Four different image sets for each patient were evaluated: image set A, Judet view plain radiographs plus axial view CT scans; image set B, Judet view plain radiographs alone; image set C, three-dimensional CT reconstructions; and image set D, CT-simulated anteroposterior and Judet views of the pelvis. The 300 image sets were viewed in random order by four orthopaedic trauma fellowship-trained surgeons who independently recorded a diagnosis. A gold standard diagnosis was determined by group consensus. Agreement among four imaging methods was evaluated by using kappa statistics for multiple raters and nominal data. Comparing the gold standard diagnosis with the four image sets, Judet view plain radiographs had a worse kappa value than CT scans (P < 0.05). The adjusted kappa values for all three image sets that included CT scans averaged greater than 0.62, showing substantial agreement, whereas the image set with plain radiographs alone (image set B) had a lower kappa value of only 0.48 (P < 0.05). In contrast to previous reports in the literature, the accuracy of plain radiographs alone was less than the accuracy of CT scans in terms of diagnosis. The interobserver reliability was also worse for plain radiographs alone.
The objectives of this study were to evaluate the ability of the Young-Burgess classification sys... more The objectives of this study were to evaluate the ability of the Young-Burgess classification system to predict mortality, transfusion requirements, and nonorthopaedic injuries in patients with pelvic ring fractures and to determine whether mortality rates after pelvic fractures have changed over time. Retrospective review. Level I trauma center. One thousand two hundred forty-eight patients with pelvic fractures during a 7-year period. None. Mortality at index admission, transfusion requirement during first 24 hours, and presence of nonorthopaedic injuries as a function of Young-Burgess pelvic classification type. Mortality compared with historic controls. Despite a relatively large sample size, the ability of the Young-Burgess system to predict mortality only approached statistical significance (P = 0.07, Kruskal-Wallis). The Young-Burgess system differentiated transfusion requirements--lateral compression Type 3 (LC3) and anteroposterior compression Types 2 (APC2) and 3 (APC3) fractures had higher transfusion requirements than did lateral compression Type 1 (LC1), anteroposterior compression Type 1 (APC1), and vertical shear (VS) (P < 0.05)--but was not as useful at predicting head, chest, or abdomen injuries. Dividing fractures into stable and unstable types allowed the system to predict mortality rates, abdomen injury rates, and transfusion requirements. Overall mortality in the study group was 9.1%, unchanged from original Young-Burgess studies 15 years previously (P = 0.3). The Young-Burgess system is useful for predicting transfusion requirements. For the system to predict mortality or nonorthopaedic injuries, fractures must be divided into stable (APC1, LC1) and unstable (APC2, APC3, LC2, LC3, VS, combined mechanism of injury) types. LC1 injuries are very common and not always benign (overall mortality rate, 8.2%).
Three porous ceramic bone graft materials were compared with regard to their ability to heal a 2.... more Three porous ceramic bone graft materials were compared with regard to their ability to heal a 2.5 cm defect created surgically in a bilateral canine radius model. The ceramic materials were analyzed at 12 and 24 weeks after surgery and included tricalcium phosphate, hydroxyapatite, and collagen hydroxyapatite, which contained a mixture of 35% tricalcium phosphate and 65% hydroxyapatite with added collagen. Each material was evaluated alone and with added bone marrow aspirate. All the implants were compared with a graft of autogenous cancellous bone in the contralateral radius. Biomechanical testing and radiographic evaluation revealed that the addition of bone marrow aspirate was essential for tricalcium phosphate and hydroxyapatite to achieve results comparable with those of cancellous bone. Collagen hydroxyapatite performed well without the addition of bone marrow, although the addition of marrow did have a positive effect. Further qualitative radiographic and histological analysis demonstrated that tricalcium phosphate was the only ceramic that showed any sign of degradation at 24 weeks. This observed degradation proved to be an important factor in evaluating radiographs because the radiodensity of collagen hydroxyapatite and hydroxyapatite interfered with the determination of radiographic union. At 24 weeks, tricalcium phosphate with bone marrow was the material that performed most like cancellous bone. In this study, the biomechanical and radiographic parameters of tricalcium phosphate with bone marrow were roughly comparable with those of cancellous bone at 12 and 24 weeks. Tricalcium phosphate was the only implant that showed significant evidence of degradation at 24 weeks by both histological and radiographic evaluations, and this degradation took place only after a degree of mechanical competence necessary for weight-bearing was achieved.
The efficacy of a bone-graft substitute (bovine-derived bone protein in a carrier of natural cora... more The efficacy of a bone-graft substitute (bovine-derived bone protein in a carrier of natural coral) in the healing of a segmental defect of a weight-bearing long bone was evaluated. Twenty dogs, divided into two groups, underwent bilateral radial osteotomies with creation of a 2.5 cm defect. On one side of each dog, the defect was filled with autogenous cancellous bone graft. Contralateral defects received, in a blinded randomized fashion, cylindrical implants consisting of natural coral (calcium carbonate) or calcium carbonate enhanced with a standard dose of bovine-derived bone protein (3.0 mg/implant; 0.68 mg bone protein/cm3). The limbs were stabilized with external fixators, and all animals underwent monthly radiographs. They were killed at 12 (group 1) or 24 (group 2) weeks, and regenerated bone was studied by biomechanical testing and histology. Radiographic union developed in all 20 radii with autogenous cancellous bone grafts and in all 10 of the radii with the composite implants. None of the radii with implants of calcium carbonate alone showed radiographic evidence of union. This represented a statistically significant difference between implant types. In addition, calcium carbonate implants both with and without bone protein demonstrated radiographic evidence of near total resorption of the radiodense carrier by 12 weeks. This resorption facilitated radiographic evaluation of healing. Mean values for biomechanical parameters of radii with the composite implants exceeded those for the contralateral controls at 12 and 24 weeks; the difference was statistically significant at 12 weeks. Histology revealed scant residual calcium carbonate carrier at either time in the defects with calcium carbonate implants; however, a moderate amount was present in defects with the composite implants. In these specimens, the residual carrier was completely surrounded by newly formed bone that may have insulated the calcium carbonate from further degradation. The present study used a carrier of granular calcium carbonate reconstituted with bovine type-I collagen to deliver an osteoinductive protein to the defect site. This carrier is of nonhuman origin (eliminating the risk of disease transmission or antigenicity) and resorbs rapidly. In this model, bovine-derived bone protein in a natural coral carrier performed consistently better than the gold standard autogenous cancellous bone graft in terms of the amount of bone formation and strength of the healed defect. This may have implications for removal of hardware or resumption of weight-bearing in certain clinical situations. These data also indicate that coralline calcium carbonate alone represents a poor option as a bone-graft substitute in this critical-sized segmental defect model.
The Journal of Bone and Joint Surgery (American), 2012
Sleep deprivation may slow reaction time, cloud judgment, and impair the ability to think. Our pu... more Sleep deprivation may slow reaction time, cloud judgment, and impair the ability to think. Our purpose was to study the cognitive and psychomotor performances of orthopaedic trauma surgeons on the basis of the amount of sleep that they obtained. We prospectively studied the performances of thirty-two orthopaedic trauma surgeons (residents, fellows, and attending surgeons) over two four-week periods at an urban academic trauma center. Testing sessions used handheld computers to administer validated cognitive and psychomotor function tests. We conducted a multivariate analysis to examine the independent association between test performance and multiple covariates, including the amount of sleep the night before testing. Our analysis demonstrated that orthopaedic surgeons who had slept four hours or less the night before the test had 1.43 times the odds (95% confidence interval, 1.04 to 1.95; p = 0.03) of committing at least one error on an individual test compared with orthopaedic surgeons who had slept more than four hours the previous night. The Running Memory test, which assesses sustained attention, concentration, and working memory, was most sensitive to deterioration in performance in participants who had had four hours of sleep or less; when controlling for other covariates, the test demonstrated a 72% increase in the odds of making at least one error (odds ratio, 1.72 [95% confidence interval, 1.02 to 2.90]; p = 0.04). No significant decrease in performance with sleep deprivation was shown with the other three tests. Orthopaedic trauma surgeons showed deterioration in performance on a validated cognitive task when they had slept four hours or less the previous night. It is unknown how performance on this test relates to surgical performance.
Eukaryotic chromosomes contain specialized structures at the termini called telomeres. This regio... more Eukaryotic chromosomes contain specialized structures at the termini called telomeres. This region of DNA is required for replication and stability of the chromosome. Telomere reduction can contribute to genetic instability and has been described in certain malignancies (e.g., colon, leukemia, giant cell tumor of bone). To determine whether telomere reduction is a generalized phenomenon in malignancies, the telomere integrity of genomic DNA isolated from tumor cells was determined from 39 individuals with 15 different malignancies categorized as musculoskeletal, epithelial, cranial, or other, and peripheral blood leukocytes from the same patient, when possible, or age-matched controls. Significant telomere reduction occurred randomly across histopathologic groups including giant cell tumor of bone, glioblastoma, colon cancer, and Wilms' tumor while telomere elongation occurred in chordoma. The other remaining 10 malignancies do not show significant differences in telomere lengths compared with controls.
Benign giant cell tumor of bone (GCT) is a primary skeletal neoplasm with an unpredictable patter... more Benign giant cell tumor of bone (GCT) is a primary skeletal neoplasm with an unpredictable pattern of biologic aggressiveness and cytogenetic findings characterized by telomeric associations and telomeric reduction. The role of maintaining telomeric integrity is performed by telomerase. To determine if telomerase activity is present, cell extracts from fibroblasts and tumor cells from five patients with GCT were analyzed and compared with HeLa (a positive control cell line). Telomerase activity was detected by visualizing the extension of radioactive telomeric repeats on DNA sequencing gels. Telomere reduction was assessed using southern blot analyses of the restriction enzyme Hinf I digested DNA with a radio-labeled telomere probe. Telomerase or telomerase-like activity was detected in the cell extracts from HeLa and tumor cells. However, GCT telomerase activity varied and was less than that observed in HeLa, but no activity was detected from fibroblasts. In addition, telomere reduction was seen in DNA isolated from both HeLa and GCT but not in fibroblasts or age-matched controls. Telomere reduction and telomerase activity may be oncogenic sustaining events required to maintain the transformed phenotype seen in GCT.
The Journal of Trauma Injury Infection and Critical Care, Apr 1, 2010
It is unknown whether pelvic ring fracture is an independent predictor of death after blunt traum... more It is unknown whether pelvic ring fracture is an independent predictor of death after blunt trauma. Few previous studies have attempted to analyze whether the high death rate observed in association with pelvic ring injury is secondary to the pelvic ring injury or merely related to many other injuries that typically are sustained in such cases. Our hypothesis was that pelvic ring fracture is an independent risk factor for death, even after accounting for the risk of death from other associated injuries. We reviewed the records of 31,550 patients who presented with blunt trauma at our Level I trauma center from 1995 to 2002. We analyzed our prospectively collected database and excluded any patient who was missing more than one demographic parameter (n = 414, 1.3% of the data set). Our study group consisted of 1,017 patients with pelvic ring fractures and 30,119 patients with blunt trauma without pelvic ring fractures. Multiple logistic regression analysis was conducted to account for the relative contribution of associated clinical criteria to mortality. A mortality model was then designed by using the regression analysis, allowing us to compare a calculated chance of death for each patient in the study group. We then compared the expected number of deaths of patients with pelvic injury with the actual number of observed deaths in that data set. Additionally, we conducted a second statistical analysis with which we compared the death rate of our pelvic ring fracture population (n = 1,017) with a matched subgroup (n = 1,017) from our patient population without pelvic ring fractures (n = 30,119). The presence of pelvic ring fracture was found to be an independent risk factor for mortality in the blunt trauma population based on both statistical methods (odds ratios, 1.9 [p < 0.001] and 2.1 [p < 0.0007]). Other significant predictors of mortality included patient age, Injury Severity Score, Glasgow Coma Scale score, systolic blood pressure and respiratory rate at admission, and several medical comorbidities. The presence of pelvic ring fracture seems to represent a clinically significant independent risk factor for mortality, even after accounting for the association with potentially severe additional body system injuries.
Intracompartmental pressure measurements are frequently used in the diagnosis of compartment synd... more Intracompartmental pressure measurements are frequently used in the diagnosis of compartment syndrome, particularly in patients with equivocal or limited physical examination findings. Little clinical work has been done to validate the clinical use of intracompartmental pressures or identify associated false-positive rates. We hypothesized that diagnosis of compartment syndrome based on one-time pressure measurements alone is associated with a high false-positive rate. Forty-eight consecutive patients with tibial shaft fractures who were not suspected of having compartment syndrome based on physical examinations were prospectively enrolled. Pressure measurements were obtained in all four compartments at a single point in time immediately after induction of anesthesia using a pressure-monitoring device. Preoperative and intraoperative blood pressure measurements were recorded. The same standardized examination was performed by the attending surgeon preoperatively, postoperatively, and during clinical follow-up for 6 months to assess clinical evidence of acute or late compartment syndrome. No clinical evidence of compartment syndrome was observed postoperatively or during follow-up until 6 months after injury. Using the accepted criteria of delta P of 30 mm Hg from preoperative diastolic blood pressure, 35% of cases (n = 16; 95% confidence interval, 21.5-48.5%) met criteria for compartment syndrome. Raising the threshold to delta P of 20 mm Hg reduced the false-positive rate to 24% (n = 11; 95% confidence interval, 11.1-34.9%). Twenty-two percent (n = 10; 95% confidence interval, 9.5-32.5%) exceeded absolute pressure of 45 mm Hg. A 35% false-positive rate was found for the diagnosis of compartment syndrome in patients with tibial shaft fractures who were not thought to have compartment syndrome by using currently accepted criteria for diagnosis based solely on one-time compartment pressure measurements. Our data suggest that reliance on one-time intracompartmental pressure measurements can overestimate the rate of compartment syndrome and raise concern regarding unnecessary fasciotomies. Diagnostic study, level II.
Minimally invasive osteosynthesis of proximal tibial fractures has grown in popularity in recent ... more Minimally invasive osteosynthesis of proximal tibial fractures has grown in popularity in recent years. This article describes a patient with a Schatzker type VI proximal tibial fracture (AO/OTA type 41.C3) and previous compartment syndrome treated with definitive fixation 8 weeks after initial injury with a precontoured proximal tibial plate and a distal targeting device. Brisk bleeding occurred during percutaneous insertion of a cortical screw at the midshaft of the tibia. Surgical exploration revealed sidewall tearing of the anterior tibial artery and vein, which were clipped at the screw insertion site. After the bleeding was controlled, the patient had a strong palpable posterior tibial pulse with no palpable dorsalis pedis pulse, and the foot remained well perfused. Function of the deep peroneal nerve was normal postoperatively. Previous concerns regarding the percutaneous treatment of proximal tibial fractures have focused on the risks of damage to the superficial peroneal ne...
We assessed whether, in contrast to reports in the literature, computed tomographic (CT) scans im... more We assessed whether, in contrast to reports in the literature, computed tomographic (CT) scans improve the ability to classify acetabular fractures in comparison with plain radiographs. Prospective. Level I trauma center. Seventy-five patients with 75 acetabular fractures treated between June 2005 and May 2006. Four different image sets for each patient were evaluated: image set A, Judet view plain radiographs plus axial view CT scans; image set B, Judet view plain radiographs alone; image set C, three-dimensional CT reconstructions; and image set D, CT-simulated anteroposterior and Judet views of the pelvis. The 300 image sets were viewed in random order by four orthopaedic trauma fellowship-trained surgeons who independently recorded a diagnosis. A gold standard diagnosis was determined by group consensus. Agreement among four imaging methods was evaluated by using kappa statistics for multiple raters and nominal data. Comparing the gold standard diagnosis with the four image sets, Judet view plain radiographs had a worse kappa value than CT scans (P < 0.05). The adjusted kappa values for all three image sets that included CT scans averaged greater than 0.62, showing substantial agreement, whereas the image set with plain radiographs alone (image set B) had a lower kappa value of only 0.48 (P < 0.05). In contrast to previous reports in the literature, the accuracy of plain radiographs alone was less than the accuracy of CT scans in terms of diagnosis. The interobserver reliability was also worse for plain radiographs alone.
The objectives of this study were to evaluate the ability of the Young-Burgess classification sys... more The objectives of this study were to evaluate the ability of the Young-Burgess classification system to predict mortality, transfusion requirements, and nonorthopaedic injuries in patients with pelvic ring fractures and to determine whether mortality rates after pelvic fractures have changed over time. Retrospective review. Level I trauma center. One thousand two hundred forty-eight patients with pelvic fractures during a 7-year period. None. Mortality at index admission, transfusion requirement during first 24 hours, and presence of nonorthopaedic injuries as a function of Young-Burgess pelvic classification type. Mortality compared with historic controls. Despite a relatively large sample size, the ability of the Young-Burgess system to predict mortality only approached statistical significance (P = 0.07, Kruskal-Wallis). The Young-Burgess system differentiated transfusion requirements--lateral compression Type 3 (LC3) and anteroposterior compression Types 2 (APC2) and 3 (APC3) fractures had higher transfusion requirements than did lateral compression Type 1 (LC1), anteroposterior compression Type 1 (APC1), and vertical shear (VS) (P < 0.05)--but was not as useful at predicting head, chest, or abdomen injuries. Dividing fractures into stable and unstable types allowed the system to predict mortality rates, abdomen injury rates, and transfusion requirements. Overall mortality in the study group was 9.1%, unchanged from original Young-Burgess studies 15 years previously (P = 0.3). The Young-Burgess system is useful for predicting transfusion requirements. For the system to predict mortality or nonorthopaedic injuries, fractures must be divided into stable (APC1, LC1) and unstable (APC2, APC3, LC2, LC3, VS, combined mechanism of injury) types. LC1 injuries are very common and not always benign (overall mortality rate, 8.2%).
Three porous ceramic bone graft materials were compared with regard to their ability to heal a 2.... more Three porous ceramic bone graft materials were compared with regard to their ability to heal a 2.5 cm defect created surgically in a bilateral canine radius model. The ceramic materials were analyzed at 12 and 24 weeks after surgery and included tricalcium phosphate, hydroxyapatite, and collagen hydroxyapatite, which contained a mixture of 35% tricalcium phosphate and 65% hydroxyapatite with added collagen. Each material was evaluated alone and with added bone marrow aspirate. All the implants were compared with a graft of autogenous cancellous bone in the contralateral radius. Biomechanical testing and radiographic evaluation revealed that the addition of bone marrow aspirate was essential for tricalcium phosphate and hydroxyapatite to achieve results comparable with those of cancellous bone. Collagen hydroxyapatite performed well without the addition of bone marrow, although the addition of marrow did have a positive effect. Further qualitative radiographic and histological analysis demonstrated that tricalcium phosphate was the only ceramic that showed any sign of degradation at 24 weeks. This observed degradation proved to be an important factor in evaluating radiographs because the radiodensity of collagen hydroxyapatite and hydroxyapatite interfered with the determination of radiographic union. At 24 weeks, tricalcium phosphate with bone marrow was the material that performed most like cancellous bone. In this study, the biomechanical and radiographic parameters of tricalcium phosphate with bone marrow were roughly comparable with those of cancellous bone at 12 and 24 weeks. Tricalcium phosphate was the only implant that showed significant evidence of degradation at 24 weeks by both histological and radiographic evaluations, and this degradation took place only after a degree of mechanical competence necessary for weight-bearing was achieved.
The efficacy of a bone-graft substitute (bovine-derived bone protein in a carrier of natural cora... more The efficacy of a bone-graft substitute (bovine-derived bone protein in a carrier of natural coral) in the healing of a segmental defect of a weight-bearing long bone was evaluated. Twenty dogs, divided into two groups, underwent bilateral radial osteotomies with creation of a 2.5 cm defect. On one side of each dog, the defect was filled with autogenous cancellous bone graft. Contralateral defects received, in a blinded randomized fashion, cylindrical implants consisting of natural coral (calcium carbonate) or calcium carbonate enhanced with a standard dose of bovine-derived bone protein (3.0 mg/implant; 0.68 mg bone protein/cm3). The limbs were stabilized with external fixators, and all animals underwent monthly radiographs. They were killed at 12 (group 1) or 24 (group 2) weeks, and regenerated bone was studied by biomechanical testing and histology. Radiographic union developed in all 20 radii with autogenous cancellous bone grafts and in all 10 of the radii with the composite implants. None of the radii with implants of calcium carbonate alone showed radiographic evidence of union. This represented a statistically significant difference between implant types. In addition, calcium carbonate implants both with and without bone protein demonstrated radiographic evidence of near total resorption of the radiodense carrier by 12 weeks. This resorption facilitated radiographic evaluation of healing. Mean values for biomechanical parameters of radii with the composite implants exceeded those for the contralateral controls at 12 and 24 weeks; the difference was statistically significant at 12 weeks. Histology revealed scant residual calcium carbonate carrier at either time in the defects with calcium carbonate implants; however, a moderate amount was present in defects with the composite implants. In these specimens, the residual carrier was completely surrounded by newly formed bone that may have insulated the calcium carbonate from further degradation. The present study used a carrier of granular calcium carbonate reconstituted with bovine type-I collagen to deliver an osteoinductive protein to the defect site. This carrier is of nonhuman origin (eliminating the risk of disease transmission or antigenicity) and resorbs rapidly. In this model, bovine-derived bone protein in a natural coral carrier performed consistently better than the gold standard autogenous cancellous bone graft in terms of the amount of bone formation and strength of the healed defect. This may have implications for removal of hardware or resumption of weight-bearing in certain clinical situations. These data also indicate that coralline calcium carbonate alone represents a poor option as a bone-graft substitute in this critical-sized segmental defect model.
The Journal of Bone and Joint Surgery (American), 2012
Sleep deprivation may slow reaction time, cloud judgment, and impair the ability to think. Our pu... more Sleep deprivation may slow reaction time, cloud judgment, and impair the ability to think. Our purpose was to study the cognitive and psychomotor performances of orthopaedic trauma surgeons on the basis of the amount of sleep that they obtained. We prospectively studied the performances of thirty-two orthopaedic trauma surgeons (residents, fellows, and attending surgeons) over two four-week periods at an urban academic trauma center. Testing sessions used handheld computers to administer validated cognitive and psychomotor function tests. We conducted a multivariate analysis to examine the independent association between test performance and multiple covariates, including the amount of sleep the night before testing. Our analysis demonstrated that orthopaedic surgeons who had slept four hours or less the night before the test had 1.43 times the odds (95% confidence interval, 1.04 to 1.95; p = 0.03) of committing at least one error on an individual test compared with orthopaedic surgeons who had slept more than four hours the previous night. The Running Memory test, which assesses sustained attention, concentration, and working memory, was most sensitive to deterioration in performance in participants who had had four hours of sleep or less; when controlling for other covariates, the test demonstrated a 72% increase in the odds of making at least one error (odds ratio, 1.72 [95% confidence interval, 1.02 to 2.90]; p = 0.04). No significant decrease in performance with sleep deprivation was shown with the other three tests. Orthopaedic trauma surgeons showed deterioration in performance on a validated cognitive task when they had slept four hours or less the previous night. It is unknown how performance on this test relates to surgical performance.
Eukaryotic chromosomes contain specialized structures at the termini called telomeres. This regio... more Eukaryotic chromosomes contain specialized structures at the termini called telomeres. This region of DNA is required for replication and stability of the chromosome. Telomere reduction can contribute to genetic instability and has been described in certain malignancies (e.g., colon, leukemia, giant cell tumor of bone). To determine whether telomere reduction is a generalized phenomenon in malignancies, the telomere integrity of genomic DNA isolated from tumor cells was determined from 39 individuals with 15 different malignancies categorized as musculoskeletal, epithelial, cranial, or other, and peripheral blood leukocytes from the same patient, when possible, or age-matched controls. Significant telomere reduction occurred randomly across histopathologic groups including giant cell tumor of bone, glioblastoma, colon cancer, and Wilms' tumor while telomere elongation occurred in chordoma. The other remaining 10 malignancies do not show significant differences in telomere lengths compared with controls.
Benign giant cell tumor of bone (GCT) is a primary skeletal neoplasm with an unpredictable patter... more Benign giant cell tumor of bone (GCT) is a primary skeletal neoplasm with an unpredictable pattern of biologic aggressiveness and cytogenetic findings characterized by telomeric associations and telomeric reduction. The role of maintaining telomeric integrity is performed by telomerase. To determine if telomerase activity is present, cell extracts from fibroblasts and tumor cells from five patients with GCT were analyzed and compared with HeLa (a positive control cell line). Telomerase activity was detected by visualizing the extension of radioactive telomeric repeats on DNA sequencing gels. Telomere reduction was assessed using southern blot analyses of the restriction enzyme Hinf I digested DNA with a radio-labeled telomere probe. Telomerase or telomerase-like activity was detected in the cell extracts from HeLa and tumor cells. However, GCT telomerase activity varied and was less than that observed in HeLa, but no activity was detected from fibroblasts. In addition, telomere reduction was seen in DNA isolated from both HeLa and GCT but not in fibroblasts or age-matched controls. Telomere reduction and telomerase activity may be oncogenic sustaining events required to maintain the transformed phenotype seen in GCT.
The Journal of Trauma Injury Infection and Critical Care, Apr 1, 2010
It is unknown whether pelvic ring fracture is an independent predictor of death after blunt traum... more It is unknown whether pelvic ring fracture is an independent predictor of death after blunt trauma. Few previous studies have attempted to analyze whether the high death rate observed in association with pelvic ring injury is secondary to the pelvic ring injury or merely related to many other injuries that typically are sustained in such cases. Our hypothesis was that pelvic ring fracture is an independent risk factor for death, even after accounting for the risk of death from other associated injuries. We reviewed the records of 31,550 patients who presented with blunt trauma at our Level I trauma center from 1995 to 2002. We analyzed our prospectively collected database and excluded any patient who was missing more than one demographic parameter (n = 414, 1.3% of the data set). Our study group consisted of 1,017 patients with pelvic ring fractures and 30,119 patients with blunt trauma without pelvic ring fractures. Multiple logistic regression analysis was conducted to account for the relative contribution of associated clinical criteria to mortality. A mortality model was then designed by using the regression analysis, allowing us to compare a calculated chance of death for each patient in the study group. We then compared the expected number of deaths of patients with pelvic injury with the actual number of observed deaths in that data set. Additionally, we conducted a second statistical analysis with which we compared the death rate of our pelvic ring fracture population (n = 1,017) with a matched subgroup (n = 1,017) from our patient population without pelvic ring fractures (n = 30,119). The presence of pelvic ring fracture was found to be an independent risk factor for mortality in the blunt trauma population based on both statistical methods (odds ratios, 1.9 [p < 0.001] and 2.1 [p < 0.0007]). Other significant predictors of mortality included patient age, Injury Severity Score, Glasgow Coma Scale score, systolic blood pressure and respiratory rate at admission, and several medical comorbidities. The presence of pelvic ring fracture seems to represent a clinically significant independent risk factor for mortality, even after accounting for the association with potentially severe additional body system injuries.
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