The Impact of Travel Distance on Patient-Reported Outcomes Following Primary Total Hip Arthroplasty.

INTRODUCTION: Total hip arthroplasties (THAs) are increasingly being performed at high-volume centers, causing some patients to travel further distances to receive care. Concerns remain that increased travel distance limits follow-up, which may impact outcomes and early return to the hospital. The purpose of this study is to evaluate the impact of travel distance on 90-day patient reported outcomes (PROs) and 90-day complication rates. METHODS: Patients undergoing inpatient primary THA at a single center by one of three surgeons between 2017 and 2021 were retrospectively reviewed. Patients whose local and distant medical records were available were included. Patients who lived > 40 miles from the location or follow-up were labeled as "travelers," and those < 40 miles were "locals." Primary outcomes included PROs as measured by Veterans Rand 12 Item Health Survey (VR-12), Hip Harris Score (HHS), and Hip Dysfunction and Osteoarthritis Outcome Score for Joint Replacement (HOOS JR). Secondary outcomes included rates of 90-day medical complications, emergency department (ED) visits, unplanned readmissions, and reoperations. RESULTS: A total of 413 patients were analyzed at a mean of 897.1 days (range, 92 to 2196) including 96 travelers. Travelers averaged 96.1 miles for follow-up (range, 40.1 to 678 miles), and locals averaged 14.1 miles for follow-up (range, 0.3 to 39.8 miles). There were no significant differences in the percentage of patients achieving minimal clinically important difference (MCID) in PROs. There was no difference in the rate of 90-day medical complications, 90-day readmissions, and reoperations. Local patients were significantly more likely to have unplanned post-operative ED visits (travelers = 0%, locals = 7.4%, P = 0.003). DISCUSSION: Travelers did not demonstrate any significant differences with respect to rates of achieving MCID in PROs or 90-day complication rates. These data suggest that increased travel distance to treatment centers does not impact outcomes following primary THA.

Radiotherapy leads to improved overall survival in patients undergoing resection for Undifferentiated pleomorphic sarcoma.

BACKGROUND AND OBJECTIVES: Undifferentiated pleomorphic sarcoma (UPS) is a frequent subtype within the heterogeneous group of soft tissue sarcomas (STS). The use of radiotherapy (RT) has become an important component of a multimodal approach to treating STS. Key studies have demonstrated that the addition of RT improves rates of local control in STS, though the effect on overall survival (OS) is less clear. Furthermore, there is very limited and conflicting evidence regarding effect of RT on overall survival in UPS. The purposes of this investigation were to examine the association between RT and OS in UPS patients undergoing surgical resection and to determine independent prognostic indicators of OS in this patient population. METHODS: This was a retrospective review of patients who underwent surgical treatment for primary UPS from 1993 to 2021. Associations between RT and OS were analyzed with Kaplan-Meier curves and log-rank testing. Cox proportional hazards regression analysis was used to determine independent prognostic factors of OS. RESULTS: One hundred and fourteen patients who underwent surgical resection of primary UPS were included in the study. Ninety-six (84.2 %) patients received RT perioperatively. Use of RT was associated with improved OS on log-rank testing (hazard ratio (HR) 0.20; 95 % confidence interval (CI) 0.11-0.36; p < 0.001). On multivariate analysis, RT was an independent predictor of improved OS (HR 0.18; 95 % CI 0.09-0.39; p < 0.001) while metastasis at presentation (HR 4.82; 95 % CI 2.26-10.27; p < 0.001) and older age (HR 1.92; 95 % CI 1.20-3.36; p = 0.02) were predictive of decreased OS. Use of RT was not significantly associated with a lower rate of local recurrence in our cohort (p = 0.49). CONCLUSIONS: Use of RT in combination with surgery was an independent prognostic indicator of improved overall survival in UPS patients. Older age and metastasis at presentation were associated with worse overall survival. Based on this and other available studies, treatment for UPS should involve limb-sparing resection when feasible with RT to ensure optimal survival.

Novel MRI scoring system to assess osseous malignancy in soft tissue sarcoma patients following radiotherapy.

PURPOSE: Radiation induced changes in bone such as radiation osteitis are commonly identified on magnetic resonance imaging (MRI) in patients who receive radiotherapy for soft tissue sarcoma (STS) management. This study proposes a novel MRI scoring system to assess osseous lesions and predict potential for malignancy based on MRI score in STS patients who received radiotherapy. METHODS: The MRI score consisted of 3 parameters: morphology, signal intensity, and progression. Interobserver reliability between MRI scores were analyzed with Cohen's kappa coefficient. Receiver operating curve (ROC) analysis was performed to determine a predictive MRI score for malignancy. RESULTS: 156 MRI's from 30 STS patients who received radiotherapy were retrospectively reviewed. Two (6.7 %) patients developed regional osseous metastasis identified on MRI. The kappa coefficient of the scoring system was 0.785 demonstrating substantial interobserver agreement (p < 0.001). ROC analysis demonstrated that the optimal cut-off value for malignant lesion on MRI was 5.5 (area under the curve 0.998; p < 0.001). CONCLUSIONS: This novel MRI scoring system recommends lesions with a score of six and above to be biopsied to distinguish if malignancy is present. We believe this scoring system can be utilized by multidisciplinary care teams to guide clinical recommendations for patients with STS and MRI findings concerning for malignancy versus radiation induced changes.

Total Knee Arthroplasty in Patients with Cerebral Palsy: A Large Database Analysis.

Cerebral palsy (CP) is a neurodevelopmental condition that can result in altered gait biomechanics, joint dysfunction, and imbalance. The complications associated with total knee arthroplasty (TKA) in patients with CP have not yet been well described. Therefore, our analysis sought to compare the 90-day and 2-year complications following TKA in patients with and without CP. The PearlDiver Mariner database was utilized to identify patients with CP undergoing primary TKA between 2010 and 2020. This cohort was matched 1:4 to a control cohort without neurodegenerative disorders based on age, sex, Elixhauser Comorbidity Index (ECI), tobacco use, obesity, and diabetes. A total of 3,257 patients (657 CP patients 2,600 controls) were included in our final analysis. A multivariable logistic regression analysis was utilized to determine the risk of CP on medical and surgical complications at 90 days and all-cause revision rates at 2 years. Patients with CP had an increased risk of acute kidney injury (odds ratio [OR]: 1.66; 95% confidence interval [CI]: 1.07-2.5; p = 0.019), pneumonia (OR: 5.63; 95% CI: 3.69-8.67; p < 0.001), urinary tract infection (OR: 5.01; 95% CI: 3.85-6.52; p < 0.001), and transfusion (OR: 2.21; 95% CI: 1.50-3.23; p < 0.001). CP patients additionally had a higher incidence of emergency department (ED) visits (OR: 5.24; 95% CI: 3.76-7.32; p < 0.001) and readmissions (OR: 5.24; 95% CI: 2.57-4.96; p < 0.001). There were no differences in rates of periprosthetic joint infection (PJI; OR: 1.23; 95% CI: 0.69-2.10; p = 0.463), surgical site infection (SSI; OR: 0.51; 95% CI: 0.12-1.46; p = 0.463), and reoperation (OR: 1.35; 95% CI: 0.71-2.43; p = 0.339) at 90 days postoperatively. The all-cause revision rates at 2 years were comparable (OR: 1.02; 95% CI: 0.67-1.51; p = 0.927). In this database review, we found that CP patients have a higher risk of medical complications in the acute postoperative period following TKA. The 90-day surgical complication and 2-year revision rates in CP patients were comparable to matched controls.

Evaluating Modern Spacer Options and Outcomes in Revision Hip Arthroplasty.

BACKGROUND: A 2-stage revision continues to be the standard treatment for periprosthetic joint infection (PJI) in hip arthroplasty. The use of "functional" spacers may allow patients to return to daily living while optimizing their health for revision surgery. We aimed to evaluate the clinical outcomes of different spacer types regarding infection eradication, mechanical complications, and functional outcomes. METHODS: Patients who have complete Musculoskeletal Infection Society criteria for diagnosis of PJI that underwent one-stage or 2-stage revision were queried in an institutional surgical database between 2002 and 2022. Out of 286 patients, 210 met our inclusion criteria and were retrospectively reviewed for demographics, laboratory values, functional and patient-reported outcomes, and subsequent revisions. The study population had 54.3% women, a mean age of 61 years old, and a mean follow-up of 3.7 ± 3.2 years. There was no difference between age, body mass index, or Charlson Comorbidity Index scores between each cohort. Spacers were categorized as nonfunctional static, nonfunctional articulating, or functional articulating. Functional spacers were defined as those that allowed full weight bearing with no restrictions. Delphi criteria were used to define revision success, and failure was defined as a recurrent or persistent infection following definitive surgery. RESULTS: There was a significantly lower reoperation rate after a definitive implant in the functional articulating cohort (P = .003), with a trending higher infection eradication rate and a lower rate of spacer failure compared to the nonfunctional spacer cohort. At 5 years, functional articulating spacers had a 94.1% survivorship rate, nonfunctional articulating spacers had an 81.2% survival rate, and nonfunctional static spacers had a 71.4% survival rate. In the functional articulating spacer cohort, 14.6% had yet to get reimplanted, with an average follow-up time of 1.4 years. CONCLUSIONS: Within this large cohort of similar demographics, functional articulating spacers may result in better clinical outcomes and infection eradication during 2-stage revision arthroplasty for PJI.

Validation of a Classification System for Optimal Application of Debridement, Antibiotics, and Implant Retention in Prosthetic Joint Infections following Total Knee Arthroplasty: A Retrospective Review.

INTRODUCTION: Periprosthetic joint infection (PJI) remains a serious complication after total knee arthroplasty (TKA). While debridement, antibiotics, and implant retention (DAIR) are considered for acute PJI, success rates vary. This study aims to assess a new scoring system's accuracy in predicting DAIR success. METHODS: 119 TKA patients (2008-2019) diagnosed with PJI who underwent DAIR were included for analysis. Data were collected on demographics, laboratory values, and clinical outcomes. This was used for validation of the novel classification system consisting of PJI acuteness, microorganism classification, and host health for DAIR indication. Statistical analysis was carried out using SPSS programming. RESULTS: Mean follow-up was 2.5 years with an average age of 65.5 ± 9.1 years, BMI of 31.9 ± 6.2 kg/m2, and CCI of 3.04 ± 1.8. Successful infection eradication occurred in 75.6% of patients. The classification system demonstrated 61.1% sensitivity, 72.4% specificity, and 87.3% positive predictive value (PPV) when the DAIR cutoff was a score less than 6. For a cutoff of less than 8, sensitivity was 100%, specificity was 37.9%, and PPV was 83.3%. CONCLUSIONS: To date, no consensus exists on a classification system predicting DAIR success. This novel scoring system, with high PPV, shows promise. Further refinement is essential for enhanced predictive accuracy.

Association between neutrophil-lymphocyte ratio, platelet-lymphocyte ratio, and survival in undifferentiated pleomorphic sarcoma (NLR, PLR, and overall survival in UPS).

BACKGROUND AND OBJECTIVES: Cancer-related inflammation has been shown to be a driver of tumor growth and progression, and there has been a recent focus on identifying markers of the inflammatory tumor microenvironment. Neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR) are inflammatory indices that have been identified as prognostic biomarkers in various malignancies. However, there is limited and conflicting data regarding their prognostic value in soft tissue sarcoma (STS) and specifically in undifferentiated pleomorphic sarcoma (UPS). METHODS: This was a retrospective review of patients who underwent surgical treatment for primary UPS from 1993 to 2021. Cutoff values for NLR and PLR were determined by receiver operating curve analysis. Cox proportional hazards regression was used to determine prognostic factors on univariate and multivariate analysis. RESULTS: Eighty-six patients were included. The optimal cutoff value was 3.3 for NLR and 190 for PLR. Both high NLR (HR 2.44; 95% CI 1.29-4.63; p = 0.005) and high PLR (HR 1.99; 95% CI 1.08-3.67, p = 0.02) were associated with worse OS on univariate analysis. On multivariate analysis, metastasis at presentation and radiotherapy were independently predictive of OS, but high NLR (HR 1.30; 95% CI 0.64-2.98; p = 0.41) and high PLR (HR 1.63; 95% CI 0.82-3.25; p = 0.17) were not predictive of survival. CONCLUSIONS: High pre-treatment NLR and PLR were associated with decreased overall survival but were not independent predictors of survival in patients undergoing resection for UPS. Until additional prospective studies can be done, survival outcomes are best predicted using previously established patient- and tumor-specific factors.

Evaluation of Local Recurrence and Diagnostic Discordance in Chondrosarcoma Patients Undergoing Preoperative Biopsy.

BACKGROUND/AIM: Preoperative biopsy of chondroid lesions has demonstrated discordance between biopsy grade and surgical resection grade. Furthermore, there is evidence to suggest risk of tumor contamination during biopsy. We evaluated our large chondrosarcoma institutional cohort to compare the rates of local recurrence based on pre-surgical biopsy, as well as other tumor characteristics and disease-related outcomes. PATIENTS AND METHODS: This was a retrospective review of patients who underwent surgical resection for chondrosarcoma at our Institution between 2005 and 2020. Outcomes included rates of local recurrence, metastasis, and overall survival. RESULTS: No significant differences were found in local recurrence and recurrence-free survival in cases of pre-operative biopsy. Thirteen (28.2%) patients had discordance between histological grade on biopsy and resection. Seven (63.6%) patients with dedifferentiation present on final resection were not identified on biopsy. The only independent predictor of recurrence-free survival and metastasis-free survival was the presence of dedifferentiation on resection. CONCLUSION: To our knowledge, this is the first study evaluating risk of local recurrence in the setting of pre-surgical biopsy in chondrosarcoma patients. Although pre-operative biopsy may contaminate biopsy tracts, appropriate surgical planning and final resection results in no difference in local recurrence rates in this cohort. However, discordance rates between preoperative biopsy and resected specimen must be considered while determining clinical treatment.

Radiation osteitis: incidence and clinical impact in the setting of radiation treatment for soft tissue sarcoma.

OBJECTIVE: Radiotherapy is an important component of soft tissue sarcoma management. Radiation osteitis is a common radiographic finding identified in the setting of radiotherapy on magnetic resonance imaging (MRI). This study aims to identify the incidence of radiation osteitis in patients who received radiotherapy for soft tissue sarcoma and if a further workup, including a biopsy, was performed for concerning MRI findings. MATERIALS AND METHODS: Medical records of patients with soft tissue sarcoma who received radiotherapy from 2008 to 2020 were retrospectively reviewed. Patients with at least one MRI of the sarcoma site following radiotherapy and information regarding radiotherapy treatments were included. MRIs of these patients were reviewed for the presence of radiation osteitis by two musculoskeletal radiologists. The clinical course of these patients including biopsy for concerning MRI findings, local recurrence, and metastasis was recorded. RESULTS: Thirty soft tissue sarcoma patients who received radiation for soft tissue sarcoma were included. Radiation osteitis was present in 18 patients. The time to osteitis present on MRI following radiotherapy completion was a median of 4.5 months. Biopsy for concerning MRI findings was performed in eight patients, five for local recurrence, and three for regional osseous metastasis. Three patients had confirmed osseous metastases. CONCLUSION: Although radiation osteitis is often a benign imaging finding, it can be difficult to discern these lesions from potentially malignant sites of disease. We recommend multidisciplinary management of soft tissue sarcoma at sarcoma centers to appropriately identify benign from malignant lesions and decide the necessity of a biopsy.

Barriers and Opportunities for Patient-Reported Outcome Implementation: A National Pediatrician Survey in the United States.

PURPOSE: To characterize pediatricians' perceived barriers and areas of confidence in assessing patient-reported outcomes (PROs) in the U.S., and to test associations of these factors with implementing PRO assessment. METHODS: Using a random sample from the members of American Medical Association, we recruited general pediatricians and pediatric subspecialists to complete a survey (July 2011 to December 2013). Perceived barriers and confidence in PRO assessment were compared by age, pediatric specialty (general pediatrics, seven subspecialties), practice settings (academic, private), and region of practice. Multivariable logistic regressions tested associations of demographic factors, barriers, and confidence factors with the implementation of PRO assessment. FINDINGS: The survey was completed by 458 participants (response rate 48.5%); of these, 40.4%, 15.9%, 15.5%, and 8.1% were general pediatricians, cardiology, hematology/oncology, and pulmonary specialists, respectively. PRO assessment was implemented by 29.0% of the pediatricians. The top five barriers for PRO assessment included limited time/manpower (79.0%), limited training (77.4%), lengthy PRO instruments (76%), lack of meaningful cut-offs on PRO scores (75.5%), and unavailable PRO instruments (75.0%). Limited knowledge of PROs (OR 4.10; 95% CI 2.21, 7.60) and unavailability of PRO instruments (OR 1.87; 95% CI 1.01, 3.49) increased the odds of not implementing the assessment, whereas confidence in PRO assessments compatible with norms (OR 0.41; 95% CI 0.23, 0.72) and perceived benefit over clinical judgment alone (OR 0.53; 95% CI 0.31, 0.93) decreased the odds of not implementing the assessment. INTERPRETATION: significant barriers to PRO assessment in pediatric settings suggest the need for providing training, resources, and practical guidance toward implementation. Patient or Public Contribution: healthcare service users contributed to this study by completing a survey and providing feedback about the barriers and areas of confidence in assessing PROs for pediatric populations.

Importance ratings on patient-reported outcome items for survivorship care: comparison between pediatric cancer survivors, parents, and clinicians.

PURPOSE: To compare importance ratings of patient-reported outcomes (PROs) items from the viewpoints of childhood cancer survivors, parents, and clinicians for further developing short-forms to use in survivorship care. METHODS: 101 cancer survivors, 101 their parents, and 36 clinicians were recruited from St. Jude Children's Research Hospital. Participants were asked to select eight items that they deemed useful for clinical decision making from each of the four Patient-Reported Outcomes Measurement Information System Pediatric item banks. These item banks were pain interference (20 items), fatigue (23 items), psychological stress (19 items), and positive affect (37 items). RESULTS: Compared to survivors, clinicians rated more items across four domains that were statistically different than did parents (23 vs. 13 items). Clinicians rated five items in pain interference domain (ORs 2.33-6.01; p's < 0.05) and three items in fatigue domain (ORs 2.22-3.80; p's < .05) as more important but rated three items in psychological stress domain (ORs 0.14-0.42; p's < .05) and six items in positive affect domain (ORs 0.17-0.35; p's < .05) as less important than did survivors. In contrast, parents rated seven items in positive affect domain (ORs 0.25-0.47; p's < .05) as less important than did survivors. CONCLUSIONS: Survivors, parents, and clinicians viewed importance of PRO items for survivorship care differently. These perspectives should be used to assist the development of PROs tools.

Development of the functional social network index for adolescent and young adult cancer survivors.

BACKGROUND: To the authors' knowledge, social network status in adolescent and young adult (AYA) cancer survivors has not been adequately studied to date. The authors developed and validated a functional social network index (FSNI) for AYA survivors, and compared its performance with that of 2 traditional indices (density and betweenness centrality). METHODS: A total of 102 AYA survivors and 102 noncancer controls who were matched for age, sex, and race were recruited from an Internet panel. Each participant reported relationships with up to 25 close friends and/or relatives. The authors developed a FSNI with reported marital status, contact frequency with friends/relatives, available resources for emotional and tangible support, and available resources for physical activity and weight management advice. Linear regression was used to analyze associations between the FSNI and cancer diagnoses, treatments, and coping skills. RESULTS: Based on the FSNI, survivors were found to have more available resources for emotional support (beta [b] = 3.02; P = .003), tangible support (b = 4.17; P<.001), physical activity advice (b = 3.94; P<.001), and weight management advice (b = 4.10; P<.001) compared with noncancer controls. Survivors of lymphoma had the largest FSNI, whereas survivors of central nervous system malignancies had the smallest (b = 2.77; P = .02). A higher FSNI was associated with better coping skills: less denial (b = 0.10; P = .01), using emotional support (b = 0.08; P = .04), using instrumental support (b = 0.12; P<.001), less behavioral disengagement (b = 0.08; P = .04), venting of emotions (b = 0.10; P = .004), positive reframing (b = 0.12; P = .003), planning for the future (b = 0.08; P = .03), and religious engagement (b = 0.16; P<.001). Density and betweenness centrality indices demonstrated neither significant differences in social networks between cancer survivors and controls (all P values >.05) nor significant associations with coping skills (all P values >.05). CONCLUSIONS: The FSNI appears to provide a better social network assessment for AYA cancer survivors than traditional indices. Cancer 2018;124:2220-7. © 2018 American Cancer Society.

Impaired Patient-Reported Outcomes Predict Poor School Functioning and Daytime Sleepiness: The PROMIS Pediatric Asthma Study.

OBJECTIVE: Poor asthma control in children is related to impaired patient-reported outcomes (PROs; eg, fatigue, depressive symptoms, anxiety), but less well studied is the effect of PROs on children's school performance and sleep outcomes. In this study we investigated whether the consistency status of PROs over time affected school functioning and daytime sleepiness in children with asthma. METHODS: Of the 238 children with asthma enrolled in the Patient-Reported Outcomes Measurement Information System (PROMIS) Pediatric Asthma Study, 169 children who provided survey data for all 4 time points were used in the analysis. The child's PROs, school functioning, and daytime sleepiness were measured 4 times within a 15-month period. PRO domains included asthma impact, pain interference, fatigue, depressive symptoms, anxiety, and mobility. Each child was classified as having poor/fair versus good PROs per meaningful cut points. The consistency status of each domain was classified as consistently poor/fair if poor/fair status was present for at least 3 time points; otherwise, the status was classified as consistently good. Seemingly unrelated regression was performed to test if consistently poor/fair PROs predicted impaired school functioning and daytime sleepiness at the fourth time point. RESULTS: Consistently poor/fair in all PRO domains was significantly associated with impaired school functioning and excessive daytime sleepiness (Ps < .01) after controlling for the influence of the child's age, sex, and race/ethnicity. CONCLUSIONS: Children with asthma with consistently poor/fair PROs are at risk of poor school functioning and daytime sleepiness. Developing child-friendly PRO assessment systems to track PROs can inform potential problems in the school setting.

Does personality affect health-related quality of life? A systematic review.

BACKGROUND: Health-related quality of life (HRQOL) is increasingly measured as an outcome for clinical and health services research. However, relatively little is known about how non-health factors affect HRQOL. Personality is a potentially important factor, yet evidence regarding the effects of personality on HRQOL measures is unclear. METHODS: This systematic review examined the relationships among aspects of personality and HRQOL. Eligible studies were identified from Medline and PsycINFO. The review included 76 English-language studies with HRQOL as a primary outcome and that assessed personality from the psychological perspective. Individuals with various health states, including ill (e.g., cancer, cardiovascular disorders), aging, and healthy, were included in this review study. RESULTS: Some personality characteristics were consistently related to psychosocial aspects more often than physical aspects of HRQOL. Personality characteristics, especially neuroticism, mastery, optimism, and sense of coherence were most likely to be associated with psychosocial HRQOL. Personality explained varying proportions of variance in different domains of HRQOL. The range of variance explained in psychosocial HRQOL was 0 to 45% and the range of explained variance in physical HRQOL was 0 to 39%. CONCLUSIONS: Personality characteristics are related to HRQOL. Systematic collection and analysis of personality data alongside HRQOL measures may be helpful in medical research, clinical practice, and health policy evaluation.

Natatory-stage cymothoid isopods: description, molecular identification and evolution of attachment.

Cymothoid isopods are parasites that have a biphasic life cycle comprised of free-swimming micropredatory stages that eventually attach permanently to fishes, on which they change sex and morphology. Thus, matching free-swimming and permanently attached life-history stages is difficult. We attempted to identify natatory-stage cymothoids by seeking matches of partial 16S rRNA gene sequences from these stages and described adult cymothoids. Natatory cymothoids were collected from light traps at Lizard Island, Great Barrier Reef and adult females were collected from fishes from several sites along the east coast of Australia. A 488bp alignment of 16S mtDNA was compared for nine species of adult cymothoids and 10 natatory-stage morphotypes. Sequences from five natatory morphotypes were similar or identical to described specimens. Sequences identical to those of Anilocra nemipteri and Cymothoa indica were collected and these are considered definitive identifications. Sequences of three other morphotypes were highly similar (97.1-99.8% homologous) to described species; the differences may reflect a low level of sequencing error, intra-specific variation or the presence of complexes of species. Figures and descriptions are provided for identified and unidentified natatory cymothoids. The sequences were also used to explore the phylogenetic relationships of these taxa using minimum evolution, maximum parsimony, maximum likelihood and Bayesian inference analyses. Topologies from each of the four phylogenetic analyses did not differ significantly. Bayesian inference and maximum likelihood methods produced identical topologies with the highest resolution. These analyses showed that some morphological characters (pereopods and uropods) of natatory stages were distributed consistently on these molecular phylogenies, raising the possibility of identifying some natatory stages to genus. Our results suggest that ancestral cymothoids attached in the buccal or gill cavity and that external attachment, as seen in Anilocra and Renocila is a derived condition that has arisen more than once.