Talar and Calcaneal Coordinate Axes Definitions across Foot Pathologies.

The understanding of foot and ankle biomechanics is improving as new technology provides more detailed information about the motion of foot and ankle bones with biplane fluoroscopy, as well as the ability to analyze the hindfoot under weightbearing conditions with weightbearing computed tomography. Three-dimensional anatomical coordinate systems are necessary to describe the 3D alignment and kinematics of the foot and ankle. The lack of standard coordinate systems across research study sites can significantly alter experimental data analyses used for pre-surgical evaluation and post-operative outcome assessments. Clinical treatment paradigms are changing based on the expanding knowledge of complex pes planovalgus morphologies or progressive collapsing foot deformity, which is present in both neurologic and non-neurologic populations. Four patient cohorts were created from 10 flexible PCFD, 10 rigid PCFD, 10 adult cerebral palsy, and 10 asymptomatic control patients. Six coordinate systems were tested on both the talus and calcaneus for all groups. The aim of this study was to evaluate axes definitions for the subtalar joint across four different patient populations to determine the influence of morphology on the implementation of previously defined coordinate systems. Different morphologic presentations from various pathologies have a substantial impact on coordinate system definitions, given that numerous axes definitions are defined through geometric fits or manual landmark selection. Automated coordinate systems that align with clinically relevant anatomic planes are preferred. Principal component axes are automatic, but do not align with clinically relevant planes and should not be used for such analysis where anatomic planes are critical.

The Impact of Social Deprivation on Anterior Urethral Stricture Recurrence After Urethroplasty - A Trauma and Urologic Reconstructive Network of Surgeons (TURNS) Analysis.

INTRODUCTION AND OBJECTIVES: Several factors influence recurrence after urethral stricture repair. The impact of socioeconomic factors on stricture recurrence after urethroplasty is poorly understood. This study aims to assess the impact that social deprivation, an area-level measure of disadvantage, has on urethral stricture recurrence after urethroplasty. METHODS: We performed a retrospective review of patients undergoing urethral reconstruction by surgeons participating in a collaborative research group. Home zip code was used to calculate Social Deprivation Indices (SDI; 0-100), which quantifies the level of disadvantage across several sociodemographic domains collected in the American Community Survey. Patients without zip code data were excluded from the analysis. The Cox Proportional Hazards model was used to study the association between SDI and the hazard of functional recurrence, adjusting for stricture characteristics as well as age and body mass index. RESULTS: Median age was 46.0 years with a median follow up of 367 days for the 1452 men included in the study. Patients in the fourth SDI quartile (worst social deprivation) were more likely to be active smokers with traumatic and infectious strictures compared to the first SDI quartile. Patients in the fourth SDI quartile had 1.64 times the unadjusted hazard of functional stricture recurrence vs patients in the first SDI quartile (95% CI 1.04-2.59). Compared to anastomotic ± excision, substitution only repair had 1.90 times the unadjusted hazard of recurrence. The adjusted hazard of recurrence was 1.08 per 10-point increase in SDI (95% CI 1.01-1.15, P = .027). CONCLUSIONS: Patient social deprivation identifies those at higher risk for functional recurrence after anterior urethral stricture repair, offering an opportunity for preoperative counseling and postoperative surveillance. Addressing these social determinants of health can potentially improve outcomes in reconstructive surgery.

Static posture weightbearing joint angle differences in patients with varus ankle osteoarthritis.

BACKGROUND: Advanced varus ankle osteoarthritis is a debilitating disease that can present with limited physical function, severe pain, and diminished quality of life. Weightbearing computed tomography enables submillimeter 3-dimensional visualization, computational analyses, and enhanced diagnoses in reporting complex degenerative changes more accurately. RESEARCH QUESTION: This study set to compare static posture weightbearing joint angle differences in healthy and varus ankle osteoarthritis patients (compensated and non-compensated). METHODS: Our retrospective assessment included 70 individuals, 44 of whom were diagnosed with advanced varus ankle osteoarthritis, and the remaining 26 were healthy participants to serve as controls. An automatic anatomic coordinate system was applied to each patient's 3-dimensional talus and calcaneus bone reconstructions from weightbearing computed tomography scans. Subtalar and midtarsal joint angles were calculated using Euler angles. RESULTS: We report statistical differences between the healthy group and both advanced varus osteoarthritis groups for midtarsal inversion/eversion. Specifically, both osteoarthritis groups' midtarsal joints were more inverted and plantarflexed as compared to healthy participants. Compensated and non-compensated subtalar joints were statistically different with respect to inversion/eversion. Non-compensated ankles exhibited a similar mean to healthy ankles who were both less inverted than compensated ankles. SIGNIFICANCE: Our study helps physicians to better understand underlying mechanisms of peritalar compensation in varus ankle osteoarthritis. Patients featuring hindfoot compensation on average had a greater subtalar joint angle indicating greater inversion than healthy and non-compensated patients.

Recommendation of minimal distal tibial length for long axis coordinate system definitions.

Accurate anatomical coordinate systems for the foot and ankle are critical for interpreting their complex biomechanics. The tibial superior-inferior axis is crucial for analyzing joint kinematics, influencing bone motion analysis during gait using CT imaging and biplane fluoroscopy. However, the lack of consensus on how to define the tibial axis has led to variability in research, hindering generalizability. Even as advanced imaging techniques evolve, including biplane fluoroscopy and weightbearing CT, there exist limitations to imaging the entire foot together with the full length of the tibia. These limitations highlight the need to refine axis definitions. This study investigated various superior-inferior axes using multiple distal tibia lengths to determine the minimal field of view for representing the full tibia long-axis. Twenty human cadaver tibias were imaged and segmented to generate 3D bone models. Axes were calculated based on coordinate definitions that required user manual input, and a gold standard mean superior-inferior axis was calculated based on the population's principal component analysis axis. Four manually calculated superior-inferior tibial axes groups were established based on landmarks and geometric fittings. Statistical analysis revealed that geometrically fitting a cylinder 1.5 times the mediolateral tibial width, starting 5 cm above the tibial plafond, yielded the smallest angular deviation from the gold standard. From these findings, we recommend a minimum field of view that includes 1.5 times the mediolateral tibial width, starting 5 cm above the tibial plafond for tibial long-axis definitions. Implementing these findings will help improve foot and ankle research generalizability and impact clinical decisions.

Characterizing and Quantifying Material Fatigue of the Artificial Urinary Sphincter Pressure Regulating Balloon.

OBJECTIVE: To characterize and quantify changes in elastic properties and in vivo pressure characteristics of pressure regulating balloons (PRB) over time, we conducted an analysis of the mechanical characteristics of the PRB after removal from patients for revision surgery. METHODS: Pressure and elasticity characteristics of new and used 61-70 cm H2O PRBs were analyzed. Pressure-volume curves were generated using commercially available urodynamics equipment. PRB pressures were measured at a standard fill volume (23 cc). Elastance was calculated by the slope of the tangent line at the inflection point of the pressure-volume curve. Tests were repeated 5 times per PRB and intraclass correlations were used to gauge test-retest reliability. Regression models were used for continuous variables based on data distribution. RESULTS: Twenty-seven used PRBs were analyzed after excluding 3 for alternative pressure ratings and 2 for occult pinpoint leaks. Time from artificial urinary sphincter placement to removal ranged from 0.02-17.6 years (median 8.4, interquartile range (IQR) 5.7-10.0). The mean pressure of all extracted PRBs: 58.8 cm H=O (± 7.4), 17 (62.9%) below the standard operating range. Each year of use in-vivo was associated with 1.09 cm H2O pressure loss on linear regression (P <.01 CI -1.52 to -0.65). PRB pressures were not significantly different according to indication for removal (1-way analysis of variance (ANOVA) P = .11). Loss of elastance was non-linear, decreasing by 1.9% per year on Poisson regression (P <.01, CI -0.03 to -0.01). When accounting for PRB age, PRB pressure was independently associated with detrusor overactivity. CONCLUSION: In PRBs tested for pressure-volume characteristics, increasing PRB age was associated with decreased pressure and elasticity.

Automatic anatomical foot and ankle coordinate toolbox.

Accurate analysis of bone position and orientation in foot and ankle studies relies on anatomical coordinate systems (ACS). Reliable ACSs are necessary for many biomechanical and clinical studies, especially those including weightbearing computed tomography and biplane fluoroscopy. Existing ACS approaches suffer from limitations such as manual input, oversimplifications, or non-physiological methods. To address these shortcomings, we introduce the Automatic Anatomical Foot and Ankle Coordinate Toolbox (AAFACT), a MATLAB-based toolbox that automates the calculation of ACSs for the major fourteen foot and ankle bones. In this manuscript, we present the development and evaluation of AAFACT, aiming to provide a standardized coordinate system toolbox for foot and ankle studies. The AAFACT was evaluated using a dataset of fifty-six models from seven pathological groups: asymptomatic, osteoarthritis, pilon fracture, progressive collapsing foot deformity, clubfoot, Charcot Marie Tooth, and cavovarus. Three analyses were conducted to assess the reliability of AAFACT. Firstly, ACSs were compared between automatically and manually segmented bone models to assess consistency. Secondly, ACSs were compared between individual bones and group mean bones to assess within-population precision. Lastly, ACSs were compared between the overall mean bone and group mean bones to assess the overall accuracy of anatomical representation. Statistical analyses, including statistical shape modeling, were performed to evaluate the reliability, accuracy, and precision of AAFACT. The comparison between automatically and manually segmented bone models showed consistency between the calculated ACSs. Additionally, the comparison between individual bones and group mean bones, as well as the comparison between the overall mean bone and group mean bones, revealed accurate and precise ACSs calculations. The AAFACT offers a practical and reliable solution for foot and ankle studies in clinical and engineering settings. It accommodates various foot and ankle pathologies while accounting for bone morphology and orientation. The automated calculation of ACSs eliminates the limitations associated with manual input and non-physiological methods. The evaluation results demonstrate the robustness and consistency of AAFACT, making it a valuable tool for researchers and clinicians. The standardized coordinate system provided by AAFACT enhances comparability between studies and facilitates advancements in foot and ankle research.

Pelvic Extirpative Surgery for the "End-Stage Irradiated Bladder".

Men with prostate cancer have the daunting task of selecting from multiple modalities of treatment. The long-term effects of radiation therapy are only now being recognized. For both patients and surgeons, the end-stage irradiated bladder poses numerous problems and challenges. Specifically, irradiated bladders with urosymphyseal fistula, radiation cystitis, and rectourethral fistula are challenging to manage and treat. This review outlines the presentation, workup, and management including cystectomy for these three devastating late complications of radiation therapy. There are special considerations when performing benign cystectomy that are not typically considered during oncologic cystectomy. We discuss an overview of the current literature regarding the "end-stage bladder" resulting from radiation therapy and the important considerations that must be acknowledged when managing these patients. It is shown that many of the less invasive and conservative options ultimately lead to cystectomy. Indeed, our review concludes that cystectomy with urinary diversion is a safe and viable option in select irradiated patients with the goal to improve quality of life.

Outcomes of Urethroplasty for Synchronous Anterior Urethral Stricture Utilizing the Trauma and Urologic Reconstruction Network of Surgeons Length, Segment and Etiology Anterior Urethral Stricture Classification System.

OBJECTIVE: To describe the characteristics, management, and functional outcomes of patients with synchronous urethral stricture disease (SUSD) utilizing a multi-institutional cohort. METHODS: Data were collected and assessed from a prospectively maintained, multi-institutional database. Patients who underwent anterior urethroplasty for urethral stricture disease (USD) were included and stratified by the presence or absence of SUSD. USD location and etiology were classified according to the Trauma and Urologic Reconstruction Network of Surgeons Length, Segment and Etiology Anterior Urethral Stricture Classification System. Anterior urethroplasty techniques were recorded for both strictures. Functional failure was compared between groups. RESULTS: One thousand nine hundred eighty-three patients were identified, of whom, 137/1983 (6.9%) had SUSD. The mean primary stricture length for patients with SUSD was 3.5 and 2.6 cm for the secondary stricture. Twelve anterior urethroplasty technique combinations were utilized in treating the 27 different combinations of SUSD. Functional failure was noted in 18/137 (13.1%) patients with SUSD vs 192/1846 (10.4%) patients with solitary USD, P = .3. SUSD was not associated with increased odds of functional failure. S classifications: S1b, P = .003, S2a, P = .001, S2b, P = .01 and S2c, P = .02 and E classifications: E3a, P = .004 and E6, P = .03, were associated with increased odds of functional failure. CONCLUSION: Repair of SUSD in a single setting does not increase the risk of functional failure compared to patients with solitary USD. Increasing S classification, S1b through S2c and E classifications E3a and E6 were associated with increased functional failure. This reinforces the importance of the Trauma and Urologic Reconstruction Network of Surgeons Length, Segment and Etiology Anterior Urethral Stricture Classification System as a necessary tool in large-scale multi-institutional analysis when assessing highly heterogenous patient populations.

Synchronous Bladder Neck Contracture Dilation at the Time of Artificial Urinary Sphincter Placement Is Safe and Effective.

OBJECTIVE: To treat men with bladder neck contracture (BNC) and stress urinary incontinence, neither long-term nor comparative data exist to support the superiority of simultaneous BNC intervention at the time of artificial urinary sphincter placement (synchronous) or staged BNC intervention followed by artificial urinary sphincter placement (asynchronous). This study aimed to compare the outcomes of patients treated with synchronous and asynchronous protocols. METHODS: Using a prospectively maintained quality improvement database, we identified all men between the years of 2001-2021 with a history of BNC and artificial urinary sphincter placement. Baseline patient characteristics and outcome measures were collected. Categorical data were assessed with Pearson's Chi-square, and continuous data were assessed using independent sample t tests or the Wilcoxon Rank-Sum test. RESULTS: In total, 112 men met the inclusion criteria. Thirty-two patients were treated synchronously, and 80 were treated asynchronously. There were no significant differences between groups across 15 relevant variables. Overall follow-up duration was 7.1 (2.8, 13.1) years. Three (9.3%) in the synchronous group and 13 (16.2%) in the asynchronous group experienced an erosion. There were no significant differences in frequency of erosion, time to erosion, artificial sphincter revision, time to revision, or BNC recurrence. BNC recurrences after artificial sphincter placement were treated with serial dilation with no early device failure or erosion. CONCLUSION: Similar outcomes are achieved following synchronous and asynchronous treatment of BNC and stress urinary incontinence. Synchronous approaches should be considered safe and effective for men with stress urinary incontinence and BNC.

Joint coverage analysis in progressive collapsing foot deformity.

Progressive collapsing foot deformity (PCFD) is characterized by a progressive subluxation of the peritalar bones and respective joints. Two-dimensional conventional radiographs are limited in their ability to visualize the peritalar bones and joints with adequate detail to describe the complex three-dimensional deformity. An improved understanding of the relationship between joint coverage and deformity would allow clinicians to use coverage analysis to distinguish among the stages of PCFD. The aim of this study was to analyze the joint coverage of the six articular relationships within the talocrural, subtalar, and Chopart joints using weightbearing computed tomography (WBCT) scans. Ten individuals with a flexible hindfoot and ten individuals with a rigid hindfoot presentation of PCFD were compared to twenty-seven asymptomatic control individuals. The three most relevant findings are: (I) the anterior-medial facet of the subtalar joint contains the greatest reduction in coverage for patients with a rigid deformity, (II) an increase in talonavicular overlap (TNO) moderately correlated with a decreased coverage in the: tibiotalar, anterior-medial subtalar, talonavicular joints, and (III) the calcaneocuboid joint lacks radiographic values to adequately quantify alignment and coverage. To conclude, there were significant differences in coverage area of various articulating regions throughout the hind- and midfoot when comparing PCFD patients to asymptomatic control individuals. Relevant radiographic measures correlating to articular coverage areas of clinical interest were identified, possibly helping to better quantify PCFD in clinical practice.

Urethral Stricture Formation After Artificial Urinary Sphincter Cuff Erosion Is Uncommon in the Absence of Pelvic Radiation.

PURPOSE: Reported rates of urethral stricture development after artificial urinary sphincter erosion are highly variable. We hypothesized that the risk of stricture is commensurate with the degree of erosion. MATERIALS AND METHODS: We reviewed our prospectively maintained quality improvement database for all patients with artificial urinary sphincter erosion from 2011 to 2022. The incidence of postoperative stricture development was compared to the severity of erosion using a graded scale: 1, <25% circumference; 2, 25%-50% circumference; 3, >50% and <100% circumference; and 4, 100% circumference. From 862 artificial urinary sphincter surgeries, 102 erosion cases were identified, and 63 with documented erosion severity were included for analysis. Additional analysis was performed on 28 cases without documented erosion severity for validation. RESULTS: Within the main cohort, urethral stricture developed in 22 (34.9%) patients. The incidence of stricture did not vary by grade of erosion (P = .73) and was not significantly higher in men with grade 4 erosion vs lower-grade erosions (32.7% vs 50.0%, P = .34). Radiation exposure was associated with a 41.1% higher incidence of stricture (P < .01) and nearly every stricture occurred in the setting of prior radiation (21 of 22; 95.5%). In the validation group, 10 (35.7%) developed stricture, mostly in the setting of radiation (8 of 10; 80%). Overall, 29 of 32 (90.6%) cases of stricture involved a history of radiation. CONCLUSIONS: Artificial urinary sphincter erosion does not lead to urethral stricture formation in most cases and is not associated with degree of erosion. Those who develop strictures nearly always have a history of pelvic radiation.

Statistical multi-level shape models for scalable modeling of multi-organ anatomies.

Statistical shape modeling is an indispensable tool in the quantitative analysis of anatomies. Particle-based shape modeling (PSM) is a state-of-the-art approach that enables the learning of population-level shape representation from medical imaging data (e.g., CT, MRI) and the associated 3D models of anatomy generated from them. PSM optimizes the placement of a dense set of landmarks (i.e., correspondence points) on a given shape cohort. PSM supports multi-organ modeling as a particular case of the conventional single-organ framework via a global statistical model, where multi-structure anatomy is considered as a single structure. However, global multi-organ models are not scalable for many organs, induce anatomical inconsistencies, and result in entangled shape statistics where modes of shape variation reflect both within- and between-organ variations. Hence, there is a need for an efficient modeling approach that can capture the inter-organ relations (i.e., pose variations) of the complex anatomy while simultaneously optimizing the morphological changes of each organ and capturing the population-level statistics. This paper leverages the PSM approach and proposes a new approach for correspondence-point optimization of multiple organs that overcomes these limitations. The central idea of multilevel component analysis, is that the shape statistics consists of two mutually orthogonal subspaces: the within-organ subspace and the between-organ subspace. We formulate the correspondence optimization objective using this generative model. We evaluate the proposed method using synthetic shape data and clinical data for articulated joint structures of the spine, foot and ankle, and hip joint.