Angina Pectoris Is Associated with Cervical Disc Disease: A Cross-Sectional, Population-Based Study Using the Medicare Expenditure Panel Survey (MEPS).

Atherosclerotic disease in the vessels that supply the cervical spine may lead to degenerative disease. In angina pectoris (AP), atherosclerotic disease leads to coronary vessel occlusion and resulting symptoms. This study aims to determine the relationship between AP and neck pain. Analysis was focused on respondents who had a history of cervical pain disorders, adjusting for demographic, education, and mental health confounders. A total of 30,461 participated in the survey. Of 1,049 respondents, 21% reported neck pain. Mean age of the respondents was 62.6 ± 16.1 years. Nonwhite race, current everyday smokers, lower family income, hypertension, and diabetes had higher prevalence of neck pain (p < 0.05). On multivariate analysis, AP was associated with increased odds of neck pain (odds ratio [OR] = 1.42 [95% confidence interval (CI) 1.04 to 1.92], p = 0.026). AP was independently associated with 42% increased odds of having neck pain. Further study into the association of cardiovascular disease with degenerative disc disease pain should be performed. (Journal of Surgical Orthopaedic Advances 33(2):093-096, 2024).

Association Between Hypercholesterolemia and Neck Pain in a Cross-sectional Population-based Study.

STUDY DESIGN: Retrospective cross-sectional analysis. SUMMARY OF BACKGROUND DATA: Degenerative changes are a major contributor to chronic neck pain. According to the vascular hypothesis of disk disease, atherosclerosis of the segmental arteries contributes to ischemia of the lumbar disks and resulting degenerative changes. Prior studies have demonstrated an association between atherosclerotic risk factors and lumbar degenerative disease. Similarly, atherosclerosis may contribute to cervical disk degeneration. Cardiovascular disease is associated with the development of atherosclerosis, particularly in small vessels to the cervical spine. Hypercholesterolemia is a major contributor to the morbidity associated with cardiovascular disease. This study aims to examine the relationship between hypercholesterolemia and neck pain. MATERIALS AND METHODS: Analysis was focused on the respondents to neck pain items of the standardized questionnaire. Odds ratios were calculated, and logistic regression analyses adjusted for demographic, education, and mental health conditions. RESULTS: There were 30,461 participants in the 2018 Medicare Expenditure Panel Survey (MEPS) survey. Of those, 1049 (3.4%) subjects responded to presence of a diagnosis of cervical disorders with neck pain. Mean age of respondents was 62.6±16.1. Overall prevalence of neck pain was 21.1%. Prevalence of neck pain was similar by age, sex, education level, and occupation ( P >0.05 for each). Neck pain was more prevalent in white race and lower total family income ( P <0.05). Current everyday smokers also had higher prevalence of neck pain ( P <0.05). Logistic regression analysis revealed a higher prevalence of neck pain in those with hypercholesterolemia after controlling for relevant covariates (adjusted odds ratio=1.54, 95% CI: 1.08-2.22, P =0.018). CONCLUSIONS: Subjects with hypercholesterolemia were 54% more likely to have neck pain after controlling for confounders. This suggests that hypercholesterolemia has a role to play in degeneration of the cervical spine. Therefore, prevention and proper management of high cholesterol may curtail the development and progression of degenerative cervical disk disease and thus, neck pain.

Oral Is as Effective as Intravenous Tranexamic Acid at Reducing Blood Loss in Thoracolumbar Spinal Fusions: A Prospective Randomized Trial.

STUDY DESIGN: A prospective randomized trial at a university affiliated tertiary medical center between February 2017 and March 2020. OBJECTIVE: The aim of this study was to compare perioperative blood loss in patients undergoing elective posterior thoracolumbar fusion who were treated with IV versus PO TXA. SUMMARY OF BACKGROUND DATA: The use of antifibrinolytic agents such as tranexamic acid (TXA) to decrease operative blood loss and allogenic blood transfusions is well documented in the literature. Although evidence supports the use of intravenous (IV) and topical formulations of TXA in spine surgery, the use of oral (PO) TXA has not been studied. METHODS: A total of 261 patients undergoing thoracolumbar fusion were randomized to receive 1.95 g of PO TXA 2 hours preoperatively or 2 g IV TXA (1 g before incision and 1 g before wound closure) intraoperatively. The sample was further stratified into three categories based on number of levels fused (one-to two-level fusions, three to five, and more than five). The primary outcome was the reduction of hemoglobin. Secondary outcomes included calculated blood loss, drain output, postoperative transfusion, complications, and length of hospital stay. Equivalence analysis was performed with a two one-sided test. RESULTS: One hundred thirty-seven patients received IV and 124 received PO TXA. The average age was 62 ±â€Š13 years (mean ±â€ŠSD), including 141 females and 120 males. Revision cases comprised of 67% of the total sample. Patient demographic factors were similar between groups except for weight, BMI, and preoperative platelet count. The mean reduction of hemoglobin was similar between IV and PO groups (3.56 vs. 3.28 g/dL, respectively; P = 0.002, equivalence). IV TXA group had a higher transfusion rate compared to PO TXA group (22 patients [19%] vs. 12 patients [10%]; P = 0.03). In addition, IV group had longer length of stay (LOS) than PO group (4.4 vs. 3.7 days; P = 0.02). CONCLUSION: Patients treated with IV and PO TXA experienced the same perioperative blood loss after small and large spinal fusions. In subgroup analysis, the intermediate (three to five level) spinal fusions had less blood loss with PO TXA than IV TXA. Given its lower cost, PO TXA represents a superior alternative to IV TXA in patients undergoing elective posterior thoracolumbar fusion and may improve health care cost-efficiency in the studied population.Level of Evidence: 1.

Propensity-Matched Comparison of 90-Day Complications in Robotic-Assisted Versus Non-Robotic Assisted Lumbar Fusion.

STUDY DESIGN: Retrospective single center propensity-matched observational cohort study that included patients who underwent 1- to 3-level lumbar fusion surgery for degenerative conditions. OBJECTIVE: To compare 90-day complication rates between robotic-assisted and non-robotic-assisted lumbar spinal fusions in propensity-matched cohorts. SUMMARY OF BACKGROUND DATA: A recent administrative database (PearlDiver) study reported increased 30-day complications with the utilization of robotic-assisted enabling technology. METHODS: Of 146 robotic-assisted cases that met inclusion criteria, 114 were successfully propensity matched to 114 patients from 214 cases who had 1 to 3 level lumbar fusion without robotic assistance based on age, sex, body mass index, smoking status, American Society of Anesthesiologist grade, number of surgical levels, primary versus revision, and surgical approach (posterior-only or anterior-posterior). We excluded tumor, trauma, infection, or deformity cases. Outcomes included surgical and medical (major/minor) complications at intraoperative, immediately postoperative, 30- and 90-day postoperative intervals, including reoperations, and readmissions within 90 days. RESULTS: All cause intraoperative complication rates were similar between non-robotic-assisted (5.3%) and robotic-assisted groups (10.5%, P = 0.366). Immediate postoperative medical complication rate was also similar between non-robotic-assisted (6.1%) and robotic-assisted groups (1.8%, P = 0.089). Thirty-day complication rates, 90-day complication rates, reoperation rates, and readmission rates showed no difference between non-robotic-assisted and robotic-assisted groups. There was no difference between return to OR for infection between the cohorts (non-robotic-assisted: 6 [5%] vs. robotic-assisted: 1 [0.8%], P = 0.119). There was however improved length of stay (LOS) in the robotic-assisted group compared with non-robotic-assisted group (2.5 vs. 3.17 days, P = 0.018). CONCLUSION: In propensity-matched cohorts, patients undergoing 1- to 3-level robotic-assisted posterior lumbar fusion for degenerative conditions did not have increased 90-day complication rate, and had a shorter length of stay compared with non-robotic-assisted patients. There findings differ from a prior administrative database study as the robotic-assisted group in the current study had 0% return to OR for malpositioned screws and 0.8% return to OR for infection.Level of Evidence: 2.

The Relationship Between Cigarette Smoking and the Prevalence, Frequency and Severity of Back Pain.

The purpose of this study was to examine the relationship between smoking and back pain in a cross-sectional analysis. Using the Osteoarthritis Initiative database, a multi-center, longitudinal, observational cohort study with 4796 participants, we examined the prevalence of back pain and of limitations in activity due to back pain, as well as the frequency and severity of back pain in participants who were current smokers compared to those who had never smoked. Data was evaluated using binary and ordinal logistic regression analyses. An increase in prevalence, frequency and severity of back pain was strongly associated with smoking. This demonstrates a relationship between smoking and back pain; however, further studies are needed to evaluate causation. (Journal of Surgical Orthopaedic Advances 29(3):165-168, 2020).

Impingement-Free Hip Flexion in Asymptomatic Young Adult Women.

BACKGROUND: Ultrasound-assisted measurement of hip flexion has demonstrated that hip flexion has been historically overestimated in men. To our knowledge, assessment of hip flexion in women using similar methods has not been reported. Establishing normative values for hip flexion is vital to aid diagnosis, management, and future research. Therefore, we asked 2 questions: (1) At what range of midsagittal hip flexion do soft-tissue impingement and femoroacetabular abutment occur in asymptomatic young adult women? (2) Do radiographic findings on a supine anteroposterior pelvic radiograph correlate with ultrasound-assisted measurements of hip flexion? METHODS: Fifty-five asymptomatic adult women volunteers (107 hips) underwent ultrasound-assisted assessment of hip flexion. Hip flexion was recorded at the initiation of labral contact and at bone-on-bone contact. Recorded motion was correlated with common radiographic measurements of hip morphology as observed on a supine anteroposterior pelvic radiograph. RESULTS: The mean age of the subjects was 26 ± 3 years (range, 21 to 35 years), and the mean body mass index was 23 ± 3 kg/m (range, 17 to 31.6 kg/m). Mean impingement-free and maximum midsagittal passive flexion were 72° ± 8° (95% confidence interval [CI], 70° to 74°) and 101° ± 11° (95% CI, 99° to 103°), respectively. There were no significant correlations between radiographic measurements of hip morphology and ultrasound-measured hip range of motion. CONCLUSIONS: Observed hip flexion in the asymptomatic hips of young women is substantially less than has been historically reported. Morphologic features that are measurable on anteroposterior pelvic radiographs do not correlate with ultrasound-measured hip flexion. Diagnosis of hip disorders and treatments that are designed to alter hip range of motion should be based on normative data. Future studies regarding surgical restoration and/or preservation of hip flexion should be based on an understanding of normal hip range of motion. CLINICAL RELEVANCE: Ultrasound-assisted hip flexion measurement established normative values to guide surgical restoration and/or preservation of hip flexion.

Magnetic resonance imaging versus ultrasound in diagnosis of distal biceps tendon avulsion.

INTRODUCTION: The severity of distal biceps tendon (DBT) injuries ranges from partial to complete tears leading to various clinical manifestation. Accuracy of early diagnosis and selection of treatment are critical to long-term recovery outcomes. Magnetic resonance imaging (MRI) or ultrasonography (US) are two commonly modalities for pre-operative diagnosis. The objective of this study was to determine the efficiency of MRI and ultrasonography US in the diagnosis of DBT rupture confirmed by operative findings. HYPOTHESIS: MRI and US are equally effective in terms of accuracy, sensitivity and specificity. MATERIAL AND METHODS: A total of 31 patients with DBT avulsion and surgical treatment were recruited for this retrospective study. All these patients received both US and MRI examinations prior to surgery. DBT avulsion was classified into partial tear and complete tear. Diagnosis outcomes by MRI and US were analyzed and compared statistically for the accuracy, sensitivity, and specificity in discriminating partial and complete DBT tears. RESULTS: The accuracy of MRI and US was 86.4% and 45.5% in diagnosis of complete DBT rupture, respectively. Accuracy rate of MRI (66.7%) was the same as US in diagnosis of partial tear. Overall accuracy rate of MRI (80.6%) was higher than US (51.6%) in diagnosis all DBT avulsion with an odds ratio of 3.9. Sensitivity and specificity of MRI were 76.0% and 50.0%, while that of ultrasonography were 62.5% and 20.0%. CONCLUSIONS: The findings of this study suggest that MRI is a more accurate imaging modality at correctly identifying the type of DBT tear although US is more cost-effective. LEVEL OF EVIDENCE: III, Cohort study, Diagnosis study.

Intravenous and Oral Tranexamic Acid Are Equivalent at Reducing Blood Loss in Thoracolumbar Spinal Fusion: A Prospective Randomized Trial.

STUDY DESIGN: A prospective randomized trial of patients enrolled at a university affiliated tertiary medical center between February and December 2017. OBJECTIVE: To compare perioperative blood loss in patients undergoing elective posterior thoracolumbar fusion who were treated with intravenous (IV) versus oral (PO) tranexamic acid (TXA). SUMMARY OF BACKGROUND DATA: The use of antifibrinolytic agents such as TXA to decrease operative blood loss and allogenic blood transfusions is well documented in the literature. While evidence supports the use of IV and topical formulations of TXA in spine surgery, the use of PO TXA has not been studied. METHODS: Eighty-three patients undergoing thoracolumbar fusion were randomized to receive 1.95 g of PO TXA 2 hours preoperatively or 2 g IV TXA (1 g before incision and 1 g before wound closure) intraoperatively. The sample was further stratified into three categories based on number of levels fused (1-2 level fusions, 3-5, and >5). The primary outcome was the reduction of hemoglobin. Secondary outcomes included calculated blood loss, drain output, postoperative transfusion, complications, and length of hospital stay. Equivalence analysis was performed with a two one-sided test (TOST). A P-value of <0.05 suggested equivalence between treatments. RESULTS: Fourty three patients received IV TXA and 40 patients received PO TXA. Patient demographic factors were similar between groups except for body mass index (BMI). The mean reduction of hemoglobin was similar between IV and PO groups (3.36 g/dL vs. 3.43 g/dL, respectively; P = 0.01, equivalence). Similarly, the calculated blood loss was equivalent (1235 mL vs. 1312 mL, respectively; P = 0.02, equivalence). Eight patients (19%) in IV TXA group received a transfusion compared with five patients in PO TXA group (13%) (P = 0.44). One patient (2% and 3% in IV and PO, respectively) in each group experienced a deep venous thrombosis/pulmonary embolism (P = 0.96). CONCLUSION: Patients treated with IV and PO TXA experienced the same perioperative blood loss after spinal fusions. Given its lower cost, PO TXA represents an excellent alternative to IV TXA in patients undergoing elective posterior thoracolumbar fusion and may improve healthcare cost-efficiency in the studied population. LEVEL OF EVIDENCE: 1.

Adductor Canal Block Versus Femoral Nerve Block for Pain Control After Anterior Cruciate Ligament Reconstruction: A Prospective Randomized Trial.

BACKGROUND: Femoral nerve block (FNB) is a commonly performed technique that has been proven to provide effective regional analgesia after anterior cruciate ligament (ACL) reconstruction. The adductor canal block (ACB) uses a similar sensory block around the knee while avoiding motor blockade of the quadriceps muscles. PURPOSE/HYPOTHESIS: The purpose of our study was to compare the efficacy of FNB versus ACB for pain control after ACL reconstruction. It was hypothesized that there would be no difference in pain levels or opioid requirements between the 2 groups. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: We performed a prospective, double-blinded, randomized controlled trial. Sixty patients undergoing primary ACL reconstruction with bone-patellar tendon-bone autograft were randomized to receive either an ACB or an FNB preoperatively. The primary outcomes assessed were pain levels (visual analog scale) and narcotic requirements for 4 days after surgery. Secondary outcomes included ability to perform a straight leg raise in the recovery room and difference in thigh circumference between the operative and nonoperative leg measured at 7 days postoperatively. RESULTS: Morphine requirements were less in the ACB group in the first 4 hours postoperatively ( P = .02). Aside from this time interval, no differences were found between the 2 groups with regard to opioid requirements and pain scores at any other time. Similarly, no differences were noted in patients' ability to perform a straight leg raise in the recovery room ( P = .13) or in thigh circumference at the first postoperative visit ( P = .09). CONCLUSION: The results of our study suggest similar efficacy in perioperative pain control with the use of an ACB for ACL reconstruction when compared with FNB. The potential long-term benefit of quadriceps preservation with the ACB is worthy of future study. REGISTRATION: NCT03033589 (ClinicalTrials.gov identifier).

Cervicothoracic Pedicle Morphometry: Using an Osteological Collection to Characterize Trends in Pedicle Size.

Pedicle screws are a common treatment option for spinal instability. Despite their popularity, pedicle screws carry the risk of transpedicular violation with subsequent neural and vascular damage. This study measured the pedicle dimensions of 500 dry specimens in an osteological collection. The data provide the orthopedic spine surgeon with an accurate measure of pedicle morphometry in light of previously limited and contradictory results. The study demonstrates that pedicle height at the cervicothoracic junction tends to increase with body height, particularly for females. Additionally, T1 pedicle width is smaller for females than males and, for males, tends to decrease with increasing body weight. These results are valuable to the spine surgeon because they suggest that taller patients may afford a larger margin for error in the vertical plane. However, they also demonstrate that heavier patients do not have wider pedicles and thus cannot be assumed to tolerate or require larger-diameter screws. (Journal of Surgical Orthopaedic Advances 27(1):33-38, 2018).

Distal Radius Fractures: AAOS Appropriate Use Criteria Versus Actual Management at a Level I Trauma Center.

BACKGROUND: The aim of this study is to determine whether the American Academy of Orthopaedic Surgeons' (AAOS) Appropriate Use Criteria (AUC) for distal radius fractures correlates with actual treatment by orthopedic hand surgeons at a level I trauma center. METHODS: ICD-9 codes were used to retrospectively identify patients who presented with wrist fractures over 1 year. Patients with isolated distal radius fractures were evaluated using the AAOS AUC application for distal radius fractures. Actual treatment was then compared with treatment recommended by the AUC. RESULTS: Of the 112 patients, 64 (57%) received treatment that matched the AAOS AUC recommendation as an "appropriate treatment." Actual management matched the AUC recommendation 100%, 7%, and 50% of the time, for Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association (AO/OTA) type A, B, and C fractures, respectively. Surgery was performed for type A, B, and C fractures 30%, 7%, and 50% of the time, respectively. For type B fractures, only the 2 cases that were managed operatively were in agreement with the AUC. For type C fractures, increased patient age (57 years and older) was significantly associated with nonoperative treatment decisions. Surgeon decisions for nonoperative treatment were in agreement with the AUC recommendations 40% of the time, whereas surgeon decisions for surgery matched the AUC recommendations 97% of the time. CONCLUSIONS: We found low agreement between actual treatment decisions and the AUC-recommended "appropriate" treatments, especially for the type B and C fractures that were managed nonoperatively. The AUC favors surgery for all intra-articular fractures, while we emphasized age and fracture displacement in our decision-making process.

Sacroiliac stabilization for sacral metastasis: A case series.

BACKGROUND: The sacrum is a rare location for spinal metastasis. These lesions are typically large and destructive by the time of diagnosis, making treatment difficult. When indicated, surgical stabilization offers pain relief and preserves independence in patients with impending and acute pathological sacral fractures. CASE DESCRIPTION: Three consecutive patients presented with sacral metastases. After either failing radiation therapy or presenting with acute fracture and instability, the patients underwent intralesional excision, bilateral L4 to ilium fusion with instrumentation, and sacroiliac (SI) screw fixation. Pain improved after surgery, and there were no wound healing complications. Two patients could continue walking without any assistive device, while one patient required a walker. CONCLUSION: Stabilization with combined modified Galveston fixation and SI screw fixation relieves pain and allows maintenance of independence in patients with sacral metastasis.

Calcaneocuboid Joint Arthritis of the Midfoot Precedes Tibiotalar Joint Arthritis.

Surgical models have best shown the relationship between ankle and mid-foot osteoarthritis, although findings regarding the calcaneocuboid joint have varied. To the authors' knowledge, no studies have evaluated the relationship between degenerative changes across the tibiotalar and calcaneocuboid joints. The goal of this study was to determine whether such a relationship exists and which joint degenerates first. A single examiner evaluated 694 tibiotalar and calcaneocuboid joints to determine the presence of osteoarthritis. Multiple linear regression analysis was conducted with a standard P value cutoff (P<.05) and 95% confidence interval. The average incidence of tibiotalar and calcaneocuboid osteoarthritis in specimens older than 40 years was compared with the incidence in those 40 years and younger. A positive correlation between tibiotalar and calcaneocuboid osteoarthritis was noted. African-American subjects were less likely than white subjects to have tibiotalar osteoarthritis. The finding of right and left tibiotalar and calcaneocuboid osteoarthritis in subjects 40 years and younger showed that midfoot arthritis was significantly more common than arthritis of the ankle. The prevalence of calcaneocuboid osteoarthritis remains stable after 40 years of age, and the prevalence of tibiotalar osteoarthritis approaches that of calcaneocuboid osteoarthritis. Calcaneocuboid osteoarthritis precedes tibiotalar osteoarthritis. Altered biomechanics involved in calcaneocuboid osteoarthritis are transferred to the tibiotalar joint, leading to tibiotalar osteoarthritis as the subject ages. Early education, surveillance, physical therapy, shoe adjustment, and orthotics may help to reduce the forces across the midfoot and prevent ankle arthritis in the long term. [Orthopedics. 2016; 39(6):e1112-e1116.].

Pedicle Morphometry of Lumbar Vertebrae: Male, Taller, and Heavier Specimens Have Bigger Pedicles.

STUDY DESIGN: An anatomic study of pedicle dimensions was performed for lumbar vertebrae from American subjects. OBJECTIVE: To quantify the dimensions of the lumbar pedicles and to better define the demographic factors that could ultimately govern the caliber selection of pedicle screws. SUMMARY OF BACKGROUND DATA: Transpedicular screw fixation allows for segmental instrumentation into multiple vertebrae across multilevel fusion area, offering considerable biomechanical advantage over the conventional hook and lateral mass fixation. Large variations in morphology from previous studies may be related to differences in demographics, sample size, and methodology. METHODS: For this study, L1-L5 vertebrae from 503 American human cadavers were directly measured with a digital caliper. Examiner measured each vertebra to determine medial-lateral pedicle width (PW) and cranial-caudal pedicle height (PH). Demographic information regarding age, sex, and race, as well as body height and weight, was available for all 503 subjects. RESULTS: PH decreased in size caudally down the lumbar spine, but PW increased in size. The largest PH was at the L1 level with a mean of 15.75 mm. The widest PW was at the L5 level with a mean of 18.33 mm. Males have larger pedicles than females for all lumbar levels. The tallest and heaviest groups generally had larger pedicles than the shorter and lighter groups, respectively. Age and race did not consistently affect pedicle dimension in a statistically significant manner. CONCLUSION: Our large-scale study of American specimens characterized the relationship between pedicle dimensions and a variety of demographic factors such as age, sex, body height, and weight. With substantial statistical power, the current study showed that male, taller, and heavier individuals had larger lumbar pedicles. LEVEL OF EVIDENCE: 3.

Lower thoracic pedicle morphometry: male, taller, and heavier specimens have bigger pedicles.

STUDY DESIGN: An anatomic study of pedicle dimensions was performed for lower thoracic vertebrae from American human subjects. OBJECTIVE: To quantify the dimensions of the lower thoracic pedicles and to better define the demographic factors that could ultimately govern the caliber selection of pedicle screws. SUMMARY OF BACKGROUND DATA: Transpedicular screw fixation allows for segmental instrumentation into multiple vertebrae across multilevel fusion area, offering considerable biomechanical advantage over the conventional hook and lateral mass fixation. Large variations in morphology from previous studies may be related to differences in demographics, sample size, and methodology. METHODS: For this study, T7-T12 vertebrae from 503 American human cadavers were directly measured with a digital caliper. Examiner measured each vertebra to determine medial-lateral pedicle width and cranial-caudal pedicle height. Demographic information regarding age, sex, and race, as well as body height and weight, was available for all 503 subjects. RESULTS: Both pedicle height and pedicle width generally increased in size caudally down the lower thoracic spine. The highest pedicle height was at the T12 level with a mean of 17.08 mm. The widest pedicle width was at the T11 level with a mean of 9.31 mm. Males have larger pedicles than females for all upper thoracic levels. The tallest and heaviest groups had larger pedicles than the shorter and lighter groups, respectively. Age and race did not consistently affect pedicle dimension in a statistically significant manner. CONCLUSION: Our large-scale study of American specimens characterized the relationship between pedicle dimensions and a variety of demographic factors such as age, sex, body height and weight. With substantial statistical power, this study showed that male, taller, and heavier individuals had larger pedicles. LEVEL OF EVIDENCE: N/A.

Pedicle morphometry of upper thoracic vertebrae: an anatomic study of 503 cadaveric specimens.

STUDY DESIGN: An anatomic study of pedicle dimensions was performed for upper thoracic vertebrae from American human subjects. OBJECTIVE: To quantify the dimensions of the upper thoracic pedicles and to better define the demographic factors that could ultimately govern the caliber selection of pedicle screws. SUMMARY OF BACKGROUND DATA: Transpedicular screw fixation allows for segmental instrumentation into multiple vertebrae across multilevel fusion area, offering considerable biomechanical advantage over the conventional hook and lateral mass fixation. Large variations in morphology from previous studies may be related to differences in demographics, sample size, and methodology. METHODS: For this study, T1-T6 vertebrae from 503 American human cadavers were directly measured with a digital caliper. Examiner measured each vertebra to determine medial-lateral pedicle width and cranial-caudal pedicle height. Demographic information regarding age, sex, and race, as well as body height and weight, was available for all 503 subjects. RESULTS: Pedicle height generally increased in size caudally down the upper thoracic spine, but the highest pedicle height was at the T3 level with a mean of 12.25 mm. Pedicle width displayed a narrowing pattern moving down. The widest pedicle width was at the T1 level with a mean of 8.66 mm. The 2 older age groups had larger pedicles than the 2 younger age groups. Males have larger pedicles than females for all upper thoracic levels. The tallest and heaviest groups had larger pedicles than the shorter and lighter groups, respectively. Race was not a significant factor in affecting pedicle dimension. CONCLUSION: Our large-scale study of American specimens characterized the relationship between pedicle dimensions and a variety of demographic factors such as age, sex, body height, and weight. With substantial statistical power, this study showed that male, older, taller, and heavier individuals had larger pedicles. LEVEL OF EVIDENCE: N/A.