Worsening of anemia increases the risks of complications and prolonged length of stay following revision total shoulder arthroplasty.

Background: There are no studies currently in the literature that assesses complications following revision total shoulder arthroplasty (TSA) in patients with varying severity of anemia. The purpose of this study was to determine the impact of preoperative anemia severity on postoperative complications following revision TSA. Methods: Patients undergoing revision TSA from 2013 to 2019 were queried in a national database. Based on previous studies' definitions of anemia, three subgroups were stratified: patients without anemia (hematocrit >36% for women, hematocrit >39% for men), patients with mild anemia (hematocrit 33% to 36% for women, hematocrit 33% to 39% for men) and patients with moderate to severe anemia (hematocrit <33% for both women and men). In this analysis, patient demographics, comorbidities, and postoperative complications were compared between the three groups. Results: Of 1559 total patients undergoing revision TSA, 1178 patients (75.6%) did not have anemia, 255 (16.3%) had mild anemia, and 126 (8.1%) had moderate/severe anemia. Following adjustment on multivariate analysis, patients with mild anemia were more likely to have postoperative transfusion and extended length of stay compared to non-anemic patients. Patients with moderate/severe anemia were at increased risk of postoperative transfusion, sepsis, extended length of stay, and reoperation compared to non-anemic patients. Discussion: From mild anemia to moderate/severe anemia, there was a stepwise increase in the risk of postoperative complications. Our study showed that there is clinical value in the preoperative correction of anemia for these patients as it relates to complications and hospital stay. Level of Evidence: III.

AIDS but not asymptomatic HIV is associated with higher 2-10-year implant survivorship following total knee arthroplasty.

INTRODUCTION: Prior studies have demonstrated HIV does not increase the risk of 2-year complications following TKA; however, the literature is sparse regarding the impact of HIV and AIDS on long-term implant survivorship. The purpose of this study was to compare the 10-year cumulative incidence and risk of revision TKA in patients with and without asymptomatic HIV, and with and without AIDS. METHODS: Patients with HIV who underwent elective TKA were identified using a national database and divided into subgroups of asymptomatic HIV (AHIV) and acquired immunodeficiency syndrome (AIDS). These patients with HIV were propensity matched based on age, sex, and Charlson Comorbidity Index (CCI) to a control group of elective TKA patients without HIV in a 1:2 ratio. Patients were also compared to an unmatched control group. RESULTS: The 10-year risk for all-cause revision TKA was higher in the HIV group compared to unmatched controls (HR 1.40, 95% CI 1.02-1.93, p = 0.038) but not matched controls (HR 1.13, 95% CI 0.77-1.63, p = 0.594). When compared to both control groups (unmatched; matched), the AIDS group had a higher risk of 10-year all-cause revision (HR 2.74, 95% CI 1.51-4.99, p < 0.001; HR 2.19, 95% CI 1.17-4.11, p = 0.014), dislocation/instability (HR 4.89, 95% CI 1.54-15.51, p = 0.007; HR 3.86, 95% CI 1.12-13.34, p = 0.033), and periprosthetic fracture [PPF] (HR 0.67, 95% CI 0.16-2.74, p = 0.002; HR 3.82, 95% CI 1.08-13.45, p = 0.037). However, patients with AIDS were not at increased risk of PJI or mechanical loosening compared to unmatched controls or matched controls. DISCUSSION: This study expands on current literature by following a nationwide cohort of HIV/AIDS patients for 10 years after TKA. Although a diagnosis of asymptomatic HIV was not associated with increased risk of 10-year revision rates following TKA, a diagnosis of AIDS was. Surgeons should ensure patients' serum CD4 level is sufficient, ideally in the normal range of 500-1500 cells per mm3, before undergoing TKA.

Trends in Extended Oral Antibiotic Prophylaxis Utilization Following Primary and Revision Total Hip Arthroplasty From 2010 to 2022.

BACKGROUND: In patients considered high-risk for infection, extended oral antibiotic (EOA) prophylaxis has been demonstrated to reduce rates of prosthetic joint infection following total hip arthroplasty (THA). Although national guidelines regarding their use have not yet been created, the increase in literature surrounding EOA prophylaxis suggests a potential change in practice patterns. The purpose of this study was to investigate the trends in utilization of EOA prophylaxis following THA from 2010 to 2022 and identify prescription patterns. METHODS: A total of 646,059 primary THA and 51,879 aseptic revision THA patients were included in this study. Patients who underwent primary or aseptic revision THA between 2010 and 2022 were identified in a national administrative claims database. Rates and duration of EOA prescriptions were calculated. A secondary analysis examined rates of utilization across demographics, including patients considered high risk for infection. RESULTS: From 2010 to 2022, utilization of EOA increased by 366% and 298% following primary and revision THA, respectively. Of patients prescribed postoperative antibiotics, 30% and 59% were prescribed antibiotics for more than 7 days following primary and revision THA, respectively. Rates of utilization were similar between high-risk individuals and the general population. CONCLUSIONS: Rates of utilization of EOA prophylaxis after THA have increased significantly since 2010. As current trends demonstrate a wide variation in prescription patterns, including in length of antibiotic duration and in patient population prescribed, guidelines surrounding the use of EOA prophylaxis after THA are necessary to promote antibiotic stewardship while preventing rates of periprosthetic joint infection.

Diagnostic and Invasive Colonoscopy Are Not Risk Factors for Revision Surgery Due to Periprosthetic Joint Infection.

BACKGROUND: Colonoscopy is routinely performed for colorectal cancer screening in patients who have a preexisting unicompartmental knee arthroplasty (UKA), total knee arthroplasty (TKA), or total hip arthroplasty (THA) prostheses. However, colonoscopy is theorized to provoke transient bacteremia, providing a potential nidus for periprosthetic joint infection. This study aimed to investigate the risk of aseptic and septic revision surgery in patients who underwent diagnostic colonoscopy or invasive colonoscopy within one year following UKA, TKA, or THA. METHODS: A retrospective cohort analysis was performed using a national database. Patients were identified using Current Procedural Terminology. In total, 52,891 patients underwent UKA, 1,049,218 underwent TKA, and 526,296 underwent THA. Data were analyzed with univariate analysis preceding multivariable logistic regressions to investigate outcomes of interest at 2 and 3 years from the index procedure. RESULTS: Diagnostic colonoscopy resulted in no increase in odds of all-cause or septic revision surgery for any prostheses. At both time points, invasive colonoscopy resulted in lower odds of all-cause revision (P < .05) for patients with UKA, decreased odds of septic revision (P < .001) for patients with TKA, and decreased odds of both all-cause and septic revision (P < .05) for patients with THA. CONCLUSION: Our results show that diagnostic colonoscopy was not a significant risk factor for revision following UKA, TKA, or THA. Paradoxically, invasive colonoscopy was protective against revision, even with very minimal use of antibiotic prophylaxis observed. This study addresses the theory that colonoscopy procedures may threaten an existing joint prosthesis via transient bacteremia and shows no increase in revision outcomes following colonoscopy. LEVEL OF EVIDENCE: Level III.

Trends of Venous Thromboembolism After Total Hip Arthroplasty in the United States: Analysis From 2011 to 2019.

BACKGROUND: In 2011, the American Academy of Orthopaedic Surgeons released a Clinical Practice Guideline` that recommended routine venous thromboembolism (VTE) prophylaxis after total joint arthroplasty. The purpose of this study was to examine (1) the change in the incidence of 90-day VTE, deep vein thrombosis, and pulmonary embolism, (2) the change in the utilization of antithrombotic agents; and (3) the change in the economic burden associated with VTE after total hip arthroplasty (THA) from 2011 to 2019. METHODS: National, administrative claims data from 2011 to 2019 were used to identify patients who underwent primary THA for osteoarthritis. Exclusions entailed liver pathology, coagulopathy, malignancy, or those on prior prescribed blood thinners before THA. Multivariable regression was used, controlling for age and Charlson Comorbidity Index for all years, with 2011 as the reference year. RESULTS: From 2011 to 2019, there was a significant reduction in 90-day VTE rates after THA, with a significant reduction in deep vein thrombosis and pulmonary embolism during this time frame as well. Of the antithrombotic agents prescribed after THA, the utilization of prescribed aspirin significantly increased and that of nonaspirin anticoagulants significantly decreased. Among nonaspirin anticoagulants, the utilization of direct factor Xa inhibitors and direct thrombin inhibitors significantly increased. The added reimbursements associated with VTE after THA significantly decreased during this period. CONCLUSION: Since 2011, the incidence and economic burden associated with VTE after THA have significantly declined. In addition, there has been an increase in prescription aspirin and direct oral anticoagulants. LEVEL OF EVIDENCE: Therapeutic, III.

Higher 2-Year Cumulative Incidence of Mental Health Disorders Following Antibiotic Spacer Placement for Chronic Periprosthetic Joint Infection following Total Joint Arthroplasty.

BACKGROUND: The relationship of chronic periprosthetic joint infection (PJI) treatment on the development and relapse of mood disorders remains largely unreported. This study aims to compare the incidence of different mental health disorders following antibiotic spacer placement for chronic PJI when compared to aseptic revisions and primary procedures. METHODS: Patients who underwent antibiotic spacer for septic total hip and knee arthroplasty (PJI THA/TKA) were identified in the PearlDiver Database using Current Procedure Terminology (CPT) codes for hip and knee antibiotic spacers. Patients who underwent aseptic revision and primary-THA/TKA were also identified using CPT codes. The incidences of depressive, anxiety, bipolar, psychotic, and stress disorders were identified within 2 years following the index procedures via Kaplan-Meier Analysis. RESULTS: The risk of depressive (hazard ratio (HR): 1.5; P < .001) and stress (HR: 1.5; P < .001) disorders were significantly higher in those who underwent PJI-THA when compared to aseptic revision, with the added risk of bipolar when compared to primary THA. The risk of depressive (HR: 1.6; P < .001), stress (HR: 1.4; P < .001), bipolar (HR: 1.3; P < .001), and psychotic disorders (HR: 1.5; P = .003) were significantly higher in those who underwent PJI-TKA when compared to aseptic revision, with the added risk of anxiety when compared to primary TKA. CONCLUSION: Patients who undergo spacer placement for septic-THA/TKA have a disproportionately higher incidence of mental health disorders within 2 years following surgery when compared those undergoing aseptic revisions and primary procedures. Due to this higher risk, physicians should strongly consider collaborative care with psychiatrists or mental health professionals. LEVEL OF EVIDENCE: III.

Treatment of Hepatitis C Virus Prior to Posterior Lumbar Fusion: No Difference in Medical Outcomes or Reoperation.

STUDY DESIGN: Retrospective cohort. OBJECTIVE: To analyze and confirm the rates of postoperative complications of patients with hepatitis C virus (HCV) undergoing primary posterior lumbar fusion (PLF) and assess whether treatment of HCV before surgery reduces complications. BACKGROUND CONTEXT: HCV causes chronic disease, leading to increased risk of cirrhosis and chronic illness. Currently, there is a lack of research regarding whether the patient's HCV is a modifiable risk factor for postoperative complications after spinal procedures. METHODS: The Mariner database was utilized to find patients from 2010 to 2018 undergoing PLF with active follow-up for a year. Cases involving same-day revision procedures and patients with a history of spine, infection, trauma, human immunodeficiency virus, hepatitis B, or neoplasm were excluded. Patients with a history of HCV diagnosis were identified and further stratified whether they had prior treatment using the national drug codes for antiviral, interferons, or ribavirin. Patients with HCV were matched with those without respect to age, sex, and comorbidity of burden. Outcome measured included 90-day medical complications, infection, readmission, and 1-year reoperation. RESULTS: There were 2,129 patients with HCV and 10,544 patients in the matched control group who underwent primary PLF. Out of the 2,129 patients, 469 (22.0.%) were treated with HCV medications before surgery. Patients with prior history of HCV had a significantly increased risk of wound complications (4.4% vs. 3.2%, odds ratio 1.56, 95% confidence interval 1.24-1.96, P =0.009), and infection (7.7% vs. 5.7%, odds ratio 1.26, 95% confidence interval 1.07-1.53, P =0.009) within 90 days of surgery. Patients treated before surgery did not have a difference in major ( P =0.205) or minor medical complications ( P =0.681) after surgery. CONCLUSIONS: Patients with prior history of HCV are at increased risk for many complications after surgery; however, this risk factor does not seem to be modifiable as the treatment group did not experience any improvement in postoperative outcomes. LEVEL OF EVIDENCE: Level III.

Asthma and Its Impact on Pediatric Patients Undergoing Surgical Management of Tibial Shaft Fractures.

Introduction Tibial shaft fractures are a common presenting injury among the pediatric population. Asthma is also a common diagnosis that is frequently encountered in this population and has a significant impact on healthcare utilization, quality of life, and mortality. Given the high prevalence of these conditions and risks of peri-anesthetic respiratory complications, the purpose of this study was to evaluate an association between asthma and the incidence of 30-day postoperative complications following the surgical management of tibial shaft fractures in the pediatric population. Methods The National Surgical Quality Improvement Program-Pediatric database was used to identify pediatric patients who underwent surgical treatment for tibial shaft fractures from 2013-2019. Patients were categorized into two groups: patients with a history of asthma and patients without a history of asthma. Differences in patient demographics, comorbidities, and postoperative complications were assessed using bivariate and multivariate analyses. Results Of the 2,649 patients who underwent surgical treatment for tibial shaft fractures, 115 (4.3%) had asthma. Compared to those without asthma, patients with a history of asthma were more likely to have other medical comorbidities. After controlling for the differences in baseline characteristics between the two groups, patients with asthma had an increased risk of prolonged hospital stay (OR 5.78; 95% CI 1.67 to 20.00; p=0.006). Conclusion Pediatric patients being surgically treated for tibial shaft fractures with asthma had an increased risk of prolonged hospital stay. It is important that proper preoperative workup, perioperative care, and understanding of the implications of asthma on postoperative recovery are appreciated to reduce prolonged hospitalization lengths and minimize hospital costs associated with tibial shaft fracture surgery.

The Antepsoas (ATP) Surgical Corridor for Lumbar and Lumbosacral Arthrodesis: A Radiographic, Anatomic, and Surgical Investigation.

STUDY DESIGN: Retrospective review of prospectively collected data. OBJECTIVE: To investigate the size of prepsoas surgical corridors, developed between the iliopsoas and prespinal vessels, at all disk levels between L1 and S1 granted by left and right lateral antepsoas (ATP) approaches. Secondary aims include evaluation of presurgery radiographic prepsoas windows between L1 and S1 with respect to the intraoperative findings. SUMMARY OF BACKGROUND DATA: The ATP technique is an evolving alternative to the transpsoas and direct anterior exposures for lumbar fusion. However, the vascular morphometric data of the ATP approach remain underexplored, especially at L5-S1. MATERIALS AND METHODS: Patients indicated for ATP lumbar-lumbosacral fusion between September 2018 and February 2020 were enrolled (n=121). Data were collected prospectively, including the following (in mm): intraoperative manual measurements of the premobilization psoas-vessel (pre-PV) window, the final postmobilization psoas-vessel (post-PV) window, and the preoperative radiographic psoas-to-vessel distance at the respective studied disk levels. RESULTS: A total of 121 patients (75 female, mean age: 55.3 yr, 81.8% right-sided approach) underwent a total of 279 levels of spinal fusion. Irrespective of the ATP access laterality, we noted ample postmobilization psoas-vessel (post-PV differential) corridors: largest at L4-L5 (36-38 mm) followed by L5-S1 (31-35 mm), L3-L4 (32-33 mm), L2-L3 (28-30 mm), and L1-L2 (20-24 mm). Similarly, the relative increases of the psoas-vessel corridors (post-PV and pre-PV differentials, averaged: 31 mm at L5-S1, 32 mm at L4-L5, 26 mm at L3-L4, 25 mm at L2-L3, and 14 mm at L1-L2) were also significant in both lateral approaches. In right flank approaches, the right vascular structures projected more dorsally compared with left-sided vasculature ( P <0.05). CONCLUSION: The ATP access offers generous bilateral prepsoas surgical windows to L1-S1 intervertebral disks, allowing for a safe anterior column release, decompression, instrumentation, and fusion.

Pseudarthrosis Following Lumbar and Lumbosacral Fusion Using the Antepsoas Technique.

STUDY DESIGN: Retrospective case-control study. OBJECTIVE: The aim of this study was to evaluate the prevalence of pseudarthrosis following antepsoas (ATP) lumbar and lumbosacral fusions. SUMMARY OF BACKGROUND DATA: Pseudarthrosis is a feared complication following spinal fusions and may affect their clinical outcomes. To date there are no sufficient data on the fusion rate following ATP lumbar and lumbosacral arthrodesis. METHODS: This is a retrospective review of 220 patients who underwent lumbar minimally invasive antepsoas (MIS-ATP) fusions between January 2008 and February 2019 who have at least 1-year postoperative computed tomography (CT) follow-up scans. Fusion was graded using CT scans imaging and adopting a 1-4 grading scale (1, definitely fused; 2, likely fused; 3, likely not fused; 4, definitely not fused/nonunion). Grades 3 or 4 indicate pseudarthrosis. RESULTS: A total of 220 patients (average age: 66 years, 82 males (37.2%), and 127 (57.7%) smokers) were included. Eight patients (3.6%) developed pseudarthrosis. A total of 693 discs were addressed using the ATP approach. Of those, 681 (98.3%) were considered fused (641 levels [92.5%] were "definitely fused" and 40 levels [5.8%] were "Likely fused") and 12 discs (1.7%) developed pseudarthrosis (seven levels [1.0%] were "likely not fused" and five levels (0.7%) were "definitely not fused"). The highest rate of pseudarthrosis was found at L5-S1 (4.8%) compared to the L1-L5 discs (0-2%). Of 127 smokers, six developed pseudarthrosis (odds ratio = 2.3, P = 0.3). The fusion rates were 95.3% and 97.8% for smokers and nonsmokers, respectively. Of the eight patients who developed pseudarthrosis, only four (50%) were symptomatic, of whom two (25%) required revision surgery. Both of these patients were smokers. The overall revision rate due to pseudarthrosis was 0.9% (two of 220 patients). CONCLUSION: The MIS-ATP technique results in a high fusion rate (96.4% of patients; 98.3% of levels). Pseudarthrosis was noted mostly at the L5-S1 discs and in smokers.Level of Evidence: 4.

Clinically detectable structural abnormalities in pediatric-onset multiple sclerosis: A large-scale magnetic resonance imaging analysis.

BACKGROUND: Multiple Sclerosis is characterized by neural demyelination. Structural magnetic resonance imaging (MRI) provides soft tissue contrast, which forms the basis of techniques for extracting regional biomarkers across a participant's brain. OBJECTIVES: To investigate the clinical presentation of multiple sclerosis in a large-scale MRI analysis that includes thorough consideration of extractable structural measurements (average and variability of regional cortical thicknesses, cortical surface measurements, and volumes). METHODS: We performed a large-scale retrospective analysis of 370 T1 structural volumetric MRIs from 64 participants with multiple sclerosis and compared them with a large cohort of neurotypical participants, consisting of 993 MRIs from 988 participants. Regionally distributed measurements of cortical thickness (average and standard deviation) were extracted along with surface area, surface curvature, and volumetric measurements. RESULTS: The largest observed finding involved regionally distributed reductions in average cortical thickness, with the parahippocampal region exhibiting the largest effect size, a finding that may be linked with known hippocampal atrophy in multiple sclerosis. Group-wise differences were also observed in terms of distributed volume, surface area, and surface curvature measurements. CONCLUSIONS: Participants with pediatric-onset multiple sclerosis present clinically with a variety of structural abnormalities, including perirhinal cortex thickness abnormalities not previously reported in the literature.

Evaluation of Validity and Specificity of the Cottle Maneuver in Diagnosis of Nasal Valve Collapse.

BACKGROUND: Despite the widespread use of the Cottle maneuver as a finding to define nasal valve collapse, no studies have confirmed the association between a positive Cottle maneuver and need for nasal valve repair. This study demonstrates the low construct validity of the Cottle maneuver. METHODS: One hundred healthy volunteer students and employees at Boston Medical Center were recruited for this study. Participants were asked to evaluate their breathing on a 10-point scale, rating their subjective airflow in each nostril while occluding the contralateral nostril, where 0 indicated complete obstruction and 10 indicated complete patency. Following the baseline ratings, participants were asked to rate their breathing once again while examiners preformed the Cottle and modified Cottle maneuvers. RESULTS: Overall, 97 percent of participants reported improved airflow in each nostril following the Cottle maneuver (p < 0.00001); 98 percent reported improved airflow in each nostril following the modified Cottle maneuver (p < 0.00001). CONCLUSIONS: If the clinical consensus regarding the observed improvement in nasal airflow is to be followed, nearly all the participants recruited are experiencing some surgically correctable nasal obstruction. Given the population from which our cohort was collected-students and residents from a medical campus-such a conclusion seems extremely unlikely. We believe the more likely explanation for the high positive test rate is flawed assumptions of the Cottle and modified Cottle maneuvers. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, V.

High Angular Resolution Diffusion MRI Reveals Conserved and Deviant Programs in the Paths that Guide Human Cortical Circuitry.

Diffusion magnetic resonance (MR) tractography represents a novel opportunity to investigate conserved and deviant developmental programs between humans and other species such as mice. To that end, we acquired high angular resolution diffusion MR scans of mice [embryonic day (E) 10.5 to postnatal week 4] and human brains [gestational week (GW) 17-30] at successive stages of fetal development to investigate potential evolutionary changes in radial organization and emerging pathways between humans and mice. We compare radial glial development as well as commissural development (e.g., corpus callosum), primarily because our findings can be integrated with previous work. We also compare corpus callosal growth trajectories across primates (i.e., humans and rhesus macaques) and rodents (i.e., mice). One major finding is that the developing cortex of humans is predominated by pathways likely associated with a radial glial organization at GW 17-20, which is not as evident in age-matched mice (E 16.5, 17.5). Another finding is that, early in development, the corpus callosum follows a similar developmental timetable in primates (i.e., macaques and humans) as in mice. However, the corpus callosum grows for an extended period of time in primates compared with rodents. Taken together, these findings highlight deviant developmental programs underlying the emergence of cortical pathways in the human brain.

Characterization of White Matter Tracts by Diffusion MR Tractography in Cat and Ferret that Have Similar Gyral Patterns.

The developmental relationships between gyral structures and white matter tracts have long been debated, but it is still difficult to discern whether they influence each other's development or are causally related. To explore this topic, this study used cats and ferrets as models for species that share similar gyral folding patterns and imaged with diffusion magnetic resonance imaging to compare white matter innervations in homologous gyri and other brain regions. Adult cat and ferret brains were analyzed via diffusion spectrum imaging tractography and homologous regions of interest were compared. Although similar genetic lineage and gyral structures would suggest analogous white matter tracts, tractography reveals significantly differing white matter connectivity in both the visual and auditory cortices. Similarities in connectivity were concentrated primarily in the highly conserved cerebellar region. These results correlate well with existing histological and functional studies of both species. Our results indicate that, while the 2 species may share similar gyral structures, they utilize different white matter connectivity; suggesting that while species may share similar gyral structures, they can develop different underlying white matter connectivity.

Neuronal Migration and Axonal Pathways Linked to Human Fetal Insular Development Revealed by Diffusion MR Tractography.

The insula is a multimodal sensory integration structure that, in addition to serving as a gateway between somatosensory areas and limbic structures, plays a crucial role in autonomic nervous system function. While anatomical studies following the development of the insula have been conducted, currently, no studies have been published in human fetuses tracking the development of neuronal migration or of white matter tracts in the cortex. In this study, we aimed to follow the neuronal migration and subsequent maturation of axons in and around the insula in human fetal ages. Using high-angular resolution diffusion magnetic resonance imaging tractography, major white matter pathways to/from the insula and its surrounding operculum were identified at a number of time points during human gestation. Pathways likely linked to neuronal migration from the ventricular zone to the inferior frontal gyrus, superior temporal region, and the insular cortex were detected in the earliest gestational age studied (15 GW). Tractography reveals neuronal migration to areas surrounding the insula occurred at different time points. These results, in addition to demonstrating key time points for neuronal migration, suggest that neurons and axonal fiber pathways underlying the insula and its surrounding gyri mature differentially despite their relationship during cortical folding.

Regional variation of white matter development in the cat brain revealed by ex vivo diffusion MR tractography.

Three-dimensional reconstruction of developing fiber pathways is essential to assessing the developmental course of fiber pathways in the whole brain. We applied diffusion spectrum imaging (DSI) tractography to five juvenile ex vivo cat brains at postnatal day (P) 35, when the degree of myelination varies across brain regions. We quantified diffusion properties (fractional anisotropy [FA] and apparent diffusion coefficient [ADC]) and other measurements (number, volume, and voxel count) on reconstructed pathways for projection (cortico-spinal and thalamo-cortical), corpus callosal, limbic (cingulum and fornix), and association (cortico-cortical) pathways, and characterized regional differences in maturation patterns by assessing diffusion properties. FA values were significantly higher in cortico-cortical pathways within the right hemisphere compared to those within the left hemisphere, while the other measurements for the cortico-cortical pathways within the hemisphere did not show asymmetry. ADC values were not asymmetric in both types of pathways. Interestingly, tract count and volume were significantly larger in the left thalamo-cortical pathways compared to the right thalamo-cortical pathways. The bilateral thalamo-cortical pathways showed high FA values compared to the other fiber pathways. On the other hand, ADC values did not show any differences across pathways studied. These results demonstrate that DSI tractography successfully depicted regional variations of white matter tracts during development when myelination is incomplete. Low FA and high ADC values in the cingulum bundle suggest that the cingulum bundle is less mature than the others at this developmental stage.