A unique posterior nutcracker syndrome combined with Wilkie syndrome: A singular case.

Left renal vein variants are not commonly observed in the general population. Usually, the renal vein runs in front of the aorta before entering the inferior vena cava, while the most common variants include the presence of a circumaortic or retroaortic renal vein. However, when present, left venal rein variants are important to recognize due to their potential clinical and surgical relevance. In this regard, CE-CT is an instrument with high sensitivity and specificity in detecting vascular anomalies and can certainly help diagnose. In this article, we present a unique case of a left venal rein compressed between the left iliac artery and vertebral bodies associated with the presence of a superior mesenteric artery Syndrome, another rare entity that occurs when the duodenum is compressed between the aorta and the superior mesenteric artery.

Stereotactic body radiation therapy for primary renal cell carcinoma: A review on behalf of the CC-AFU.

INTRODUCTION: The incidence of localized renal cell carcinoma (RCC) is on the rise among individuals aged 70 and older. While the gold standard for treatment remains surgical resection, some elderly and frail patients with comorbidities are not eligible for this procedure. In selected cases, percutaneous thermal ablation, such as cryotherapy, microwave and radiofrequency, offers less invasive options. General anesthesia is sometimes necessary for such treatments, but most of the procedures can be conducted using mild or deep conscious sedation. This approach is preferably recommended for small cT1a tumors situated at a distance from the renal hilum and/or ureter. Active surveillance remains an alternative in the case of small low grade RCC although it may induce anxiety in certain patients. Recent research has highlighted the potentials of stereotactic ablative body radiotherapy (SABR) as a noninvasive, well-tolerated, and effective treatment for small renal tumors. This narrative review aims to explore recent advances in SABR for localized RCC, including appropriate patient selection, treatment modalities and administration, as well as efficacy and tolerance assessment. MATERIAL AND METHODS: We conducted a literature review using the terms [kidney cancer], [renal cell carcinoma], [stereotactic radiotherapy], [SBRT], and [SABR] in the Medline, PubMed, and Embase databases, focusing on prospective and relevant retrospective studies published in English. RESULTS: Studies report local control rates ranging from 70% to 100% with SABR, highlighting its efficacy in treating RCC. The decline in glomerular filtration rate (GFR) is approximately -5 to -17mL/min over the years following SABR. Common toxicities are rare, primarily CTCAE grade 1, include fatigue, nausea, chest or back pain, diarrhea, or gastritis. CONCLUSION: Stereotactic ablative body radiotherapy (SABR) may be considered as a viable option for patients with localized RCC who are not suitable candidates for surgery with a high local control rate and a favorable safety profile. This approach should be discussed in a multidisciplinary meeting and results from ongoing clinical trials are awaited.

[Chronic kidney disease in geriatrics]. / La maladie rénale chronique en gériatrie.

Chronic kidney disease (CKD) affects almost 10% of the world's population, and over 30% of people aged over 70 [1,2]. The overall incidence of treated CKD is stable in France, but continues to rise sharply in people aged over 85 [3]. In its advanced stages, CKD is associated with numerous complications linked to disturbances in water, acid-base and phosphocalcium balance, as well as anemia and increased cardiovascular risk. A better understanding of risk factors, improved practices to promote nephroprotection, and progress in therapeutic education and preparation for suppletive techniques would help reduce this risk.

[The kidney, its anatomy and main functions]. / Le rein, son anatomie et ses grandes fonctions.

The kidney performs several major functions: it eliminates toxins produced by cellular or xenobiotic metabolism, regulates the homeostasis of the internal environment and plays a hormonal role, producing erythropoietin, calcitriol and renin. Maintaining the body's homeostasis (hydric, ionic [sodium, potassium, calcium, phosphorus, etc.] or acid-base balance) requires the successive action of plasma filtration, followed by reabsorption/secretion mechanisms, which take place in the various portions of the kidney's functional unit known as the nephron. The initial part of the nephron, the glomerulus, is the site of filtration, while the tubule, which collects the glomerular filtrate, is the site of reabsorption/secretion, leading to the composition of the final urine. It's important to understand how these different structures work, before tackling the various disorders that can affect the kidney.

[Hydrosodium balance in aging]. / La balance hydrosodée au cours du vieillissement.

One of the kidney's major functions is to adjust the water and sodium balance in order to maintain a state of equilibrium. In the course of aging, even in the absence of renal pathology, changes are observed not only in renal macrostructure (reduction in kidney size, increase in the number of cysts), but also in microstructure (arteriosclerosis, glomerulosclerosis, fibrosis and tubular atrophy). All these changes can disrupt the homeostasis of water and sodium balances. The aim of this article is to review the physiology of water and sodium stores, and to assess the impact of aging on the regulatory loops of these different systems.

[Acute renal failure in geriatrics]. / Insuffisance rénale aiguë en gériatrie.

Acute renal failure (ARF) is a frequent medical problem, affecting 20% of hospitalized patients. Aging leads to functional changes in the kidney, disruptions to hydrosodium homeostasis, and is associated with a higher prevalence of chronic kidney disease due to the impact of numerous chronic illnesses (diabetes, arterial hypertension, benign prostatic hypertrophy, etc.). All these age-related impairments hamper the kidney's ability to adapt to acute events. While elderly subjects can develop all types of AKI, they are particularly at risk of iatrogenic AKI due to polymedication, functional AKI due to a change in their ability to maintain hydrosodium homeostasis, and obstructive AKI linked to urological pathologies.

Stabilizing Mechanisms in Patients Treated Using Hill-Sachs Remplissage With Bankart Repair in Abduction-External Rotation Position.

BACKGROUND: Hill-Sachs lesion (HSL) remplissage with Bankart repair (RMBR) provides a minimally invasive solution for treating HSLs and glenoid bone defects of <25%. The infraspinatus tendon is inserted into the HSL during the remplissage process, causing the infraspinatus to shift medially, leading to an unknown effect on glenohumeral alignment during the resting abduction-external rotation (ABER) and muscle-active states. PURPOSE/HYPOTHESIS: The purpose of this study was to evaluate the possible check-rein effect and muscle-active control in stabilizing the glenohumeral joint after RMBR in vivo. We hypothesized that the check-rein effect and active control would stabilize the glenohumeral joint in the ABER position in patients after RMBR. STUDY DESIGN: Controlled laboratory study. METHODS: We included 42 participants-22 patients in group A who met the inclusion criteria after RMBR and 20 healthy participants in group B without shoulder laxity. Three-dimensional magnetic resonance imaging was performed to analyze the alignment relationship of the glenohumeral joint with and without muscular activity. Ultrasonic shear wave elastography was used to evaluate the elastic properties of the anterior capsule covered with the anterior bands of the inferior glenohumeral ligament. RESULTS: Patients who underwent RMBR demonstrated more posterior (-1.81 ± 1.19 mm vs -0.76 ± 1.25 mm; P = .008) and inferior (-1.05 ± 0.62 mm vs -0.45 ± 0.48 mm; P = .001) shifts of the humeral head rotation center and less anterior capsular elasticity (70.07 ± 22.60 kPa vs 84.01 ± 14.08 kPa; P = .023) than healthy participants in the resting ABER state. More posterior (-3.17 ± 0.84 mm vs -1.81 ± 1.19 mm; P < .001) and less-inferior (-0.34 ± 0.56 mm vs -1.05 ± 0.62 mm; P < .001) shifts of the humeral head rotation center and less anterior capsular elasticity (36.57 ± 13.89 kPa vs 70.07 ± 22.60 kPa; P < .001) were observed in the operative shoulder during muscle-active ABER than in resting ABER states. CONCLUSION: The check-rein effect and muscle-active control act as stabilizing mechanisms in RMBR during the ABER position. CLINICAL RELEVANCE: Stabilizing mechanisms in RMBR during the ABER position include the check-rein effect and muscle-active control.

The role of radiation therapy for de novo metastatic bladder and renal cancers.

Metastatic bladder and renal cancers account respectively for 2.1% and 1.8% of cancer deaths worldwide. The advent of immune checkpoint inhibitors has revolutionized the management of metastatic disease, by demonstrating considerable improvements in overall survival. However, despite initial sensitivity to immune checkpoint inhibitors for most patients, both bladder and renal cancer are associated with short progression-free survival and overall survival, raising the need for further strategies to improve their efficacy. Combining systemic therapies with local approaches is a longstanding concept in urological oncology, in clinical settings including both oligometastatic and polymetastatic disease. Radiation therapy has been increasingly studied with either cytoreductive, consolidative, ablative or immune boosting purposes, but the long-term impact of this strategy remains unclear. This review intends to address the impact of radiation therapy with either curative or palliative intent, for synchronous de novo metastatic bladder and renal cancers.

2022 Recommendations of the AFU Lithiasis Committee: Endoscopic description of renal papillae and stones.

Endoscopic observation is performed during treatments by flexible ureteroscopy to differentiate in situ between renal papillary abnormalities and stones based on their concordance with Daudon's morphological/composition descriptions adapted to endoscopy. These intraoperative visual analyses are now an integral part of the urinary stone disease diagnostic approach in addition to the morphological/structural and spectrophotometric analysis that remains the reference exam, but that loses information on the stone component representativeness due to the development of in situ laser lithotripsy. These are the first practical recommendations on the endoscopic description of renal papillae and stones. METHODOLOGY: These recommendations were developed using two methods: the Clinical Practice Recommendations (CPR) and the ADAPTE method, depending on whether the question was considered in the European Association of Urology (EAU) recommendations (https://uroweb.org/guidelines/urolithiasis [EAU Guidelines on urolithiasis. 2022]) and their adaptability to the French context.

2022 Recommendations of the AFU Lithiasis Committee: Specific cases - chronic kidney disease, bilateral stones, and solitary kidney.

Chronic kidney disease, diabetes and hypertension are risk factors of kidney function impairment. The relative risk of kidney failure is 1.52 in patients with urinary stone disease. The various techniques used to remove upper urinary tract stones generally do not alter kidney function in patients with normal kidney function and may sometimes improve kidney function or slow its deterioration in patients with kidney disease. Compared to the asynchronous treatment of bilateral renal and ureteral stones, concomitant treatment is associated with higher risk of anuria and the need of additional interventions, in the absence of postoperative stenting. For the treatment of solitary kidney stones, the absence of postoperative stenting increases the risk of postoperative anuria. Moreover, the multiplication of percutaneous nephrolithotomy access tracts increases the risk of bleeding and that of kidney function impairment. METHODOLOGY: These recommendations were developed according to two methods: the Clinical Practice Recommendations (CPR) method and the ADAPTE method, depending on whether the question was considered in the European Association of Urology (EAU) recommendations (https://uroweb.org/guidelines/urolithiasis) [EAU Guidelines on urolithiasis. 2022] and their adaptability to the French context.

Volumetric and functional outcomes at 1-year between percutaneous-ablation and partial-nephrectomy for T1b renal tumors.

INTRODUCTION: Indication for percutaneous-ablation (PA) is gradually expanding to renal tumors T1b (4-7cm). Few data exist on the alteration of renal functional volume (RFV) post-PA. Yet, it is a surrogate marker of post partial-nephrectomy (PN) glomerular filtration rate (GFR) impairment. The objective was to compare RFV and GFR at 1-year post-PN or PA, in this T1b population. METHODS: Patients with unifocal renal tumor≥4cm treated between 2014 and 2019 were included. Tumor, homolateral (RFVh), contralateral RFV, and total volumes were assessed by manual segmentation (3D Slicer) before and at 1 year of treatment, as was GFR. The loss of RFV, contralateral hypertrophy, and preservation of GFR were compared between both groups (PN vs. PA). RESULTS: 144 patients were included (87PN, 57PA). Preoperatively, PA group was older (74 vs. 59 years; P<0.0001), had more impaired GFR (73 vs. 85mL/min; P=0.0026) and smaller tumor volume(31.1 vs. 55.9cm3; P=0.0007) compared to PN group. At 1 year, the PN group had significantly more homolateral RFV loss (-19 vs. -14%; P=0.002), and contralateral compensatory hypertrophy (+4% vs. +1,8%; P=0.02, respectively). Total-RFV loss was similar between both (-21.7 vs. -19cm3; P=0.07). GFR preservation was better in the PN group (95.9 vs. 90.7%; P=0.03). In multivariate analysis, age and tumor size were associated with loss of RFVh. CONCLUSION: For renal tumors T1b, PN is associated with superior compensatory hypertrophy compared with PA, compensating for the higher RFVh loss, resulting in similar ΔRFV-total between both groups. The superior post-PN GFR preservation suggests that the preserved quantitative RFV factor is insufficient. Therefore, the underlying quality of the parenchyma would play a major role in postoperative GFR.

The effect of acute equine temporomandibular joint inflammation on response to rein-tension and kinematics.

Background: Although the temporomandibular joint (TMJ) is the major contact point between the reins in the riders' hand, the bit in the mouth, and the rest of the horse under saddle, the role of inflammation of this joint on equine locomotion and rein tension is unknown. Objective: To determine the effect of acute TMJ inflammation on rein-tension and horse movement when horses were long-reined on a treadmill. Study design: A randomized, controlled, cross-over design. Methods: Five horses were trained by one clinician to walk and trot on a treadmill wearing long-reining equipment instrumented with a rein-tension device and reflective optical tracking markers. Subjective assessment of horse's dominant side, and movement, were determined without rein-tension (free walk and trot); and with rein-tension (long-reined walk and trot). Continuous rein-force data from both sides were collected over ~60s from each trial. Movement was recorded using a 12-camera optical motion capture system. One randomly assigned TMJ was subsequently injected with lipopolysaccharide and the treadmill tests repeated by investigators blinded to treatment side. A second, identical assessment was performed 10 days later with the opposite TMJ being the target of intervention. Results: All horses showed reduced rein-tension on the injected (inflamed) side. Increased rein-tension was required on the non-injected side at trot, to maintain them in the correct position on the treadmill post-injection. The only kinematic variable to show any significant change due to rein tension or TMJ inflammation during the walk or trot was an increase in forward head tilt in the presence of rein tension in the trot after injection. Main limitations: Low number of horses and investigation of response to acute inflammation only. Conclusion: TMJ inflammation changed, subjectively and objectively, the response to rein-input, but the horses did not become lame.

[Results of the management of kidney cancer with extension into the inferior vena cava: A retrospective, single-center, observational study]. / Résultats de la prise en charge des cancers du rein avec extension dans la veine cave inférieure : étude observationnelle rétrospective monocentrique.

OBJECTIVES: The aim of our study was to evaluate the morbidity and mortality, as well as the oncogical results of patients who had undergone surgical procedure for a kidney cancer with thrombus extension into the inferior vena cava. MATERIALS AND METHODS: Between January 2004 and April 2020, 57 patients were operated by enlarged nephrectomy with thrombectomy for kidney cancer with thrombus extension in the inferior vena cava. Twelve patients (21%) with the use of cardiopulmonary bypass because the thrombus was upper than the sus-hepatic veins. Twenty-three patients (40.4%) were metastatic at diagnosis. RESULTS: Perioperative mortality was 10.5%, without difference according to surgical technique. Morbidity during hospitalization was 58%, without difference according to surgical technique. Median follow-up was 40.8±40.1months. Overall survival at 2 and 5years was 60% and 28%, respectively. At 5years, the principal prognostic factor was the metastatic status at diagnosis, in multivariate analysis (OR: 0.15, P=0.03). Progression free survival mean was 28.2±40.2months. Progression free survival at 2 and 5years was 28% and 18%, respectively. All the patients who were metastatic at diagnosis had a recurrence in an average time of 5.7months (median of 3months). Thirteen percent of patients can be considered cured at the end of the study. CONCLUSION: Morbidity and mortality of this surgery remain important. The metastatic status at diagnosis has appeared to be the principal prognostic factor on the survival of these patients. LEVEL OF EVIDENCE: Level 4: retrospective study.

Total clipless laparoscopic nephrectomy carried out with the LigaSure device: Preliminary experience.

BACKGROUND: Total laparoscopic nephrectomy has become the standard method for the removal of diseased kidneys. OBJECTIVES: The purpose of this study was to evaluate the feasibility of the LigaSure vessel closure system during laparoscopic nephrectomy. METHODS: From January 2018 to June 2018, the LigaSure device was used in 5 patients undergoing laparoscopic nephrectomy for non functional kidney. Nephrectomy was carried out without the use of clips or sutures for vessel closure. We report intraoperative findings, conversion rates, blood loss, operative time, morbidity, and postoperative outcomes. RESULTS: Median operative time was 45minutes (range 25 to 60min). Median blood loss was 30mL (range 10 to 50mL). No conversions to open surgery were necessary. No patients experienced major bleeding intraoperatively or postoperatively. All patients left the hospital one day after the procedure. Histopathological examination of the removed kidneys was in favor of chronic non specific pyelonephritis. CONCLUSIONS: For the treatment of the renal pedicle during total laparoscopic nephrectomy of a destroyed kidney, the LigaSure device appears to be feasible and effective. Our experience is the first to demonstrate the advantages of LigaSure® in laparoscopic nephrectomy: reduction in operating time, blood loss, transfusions and length of stay in hospital.

[Impact of delay before partial nephrectomy of a localized kidney tumor]. / Impact du délai avant prise en charge par néphrectomie partielle d'une tumeur du rein localisée.

INTRODUCTION: Partial nephrectomy is the treatment of choice for small localized renal tumors. In case of doubt, a biopsy can confirm the diagnosis. The aim of this study was to evaluate the impact of a delayed time to partial nephrectomy on cancer development. MATERIALS AND METHODS: Our single center study enrolled localized renal tumor patients who underwent a partial nephrectomy between 2015 and 2020; the collected data were included in the uroCCR prospective database. The histopathological stage of the tumors and the recurrence rate in patients treated with surgery >90 days after diagnosis were investigated. The impact a preoperative biopsy on was also explored. Statistical significance was tested using Student's t-test and Chi-squared test (SPSS software). RESULTS: The cohort consisted of 179 patients, among which 41 (23 %) received a preoperative biopsy. 89 patients (50 %) were treated surgically >3 months after diagnosis. The median time to nephrectomy was 86 days (13-1 037). A delayed time to surgery did not lead to significantly higher recurrence rates (P=0.66). Preoperative biopsy led to a doubling time to surgery (P<0.001) but was neither correlated to a more severe tumor stage (P=0.944) nor to a higher recurrence rate (P=0.08). Tumor growth was not significantly different with or without the presence of a biopsy (P=0.122). CONCLUSION: Our data evidence that a substantial delayed time to partial nephrectomy does not result in a negative impact on cancer prognosis in localized renal tumor patients.

French AFU Cancer Committee Guidelines - Update 2022-2024: Upper urinary tract urothelial cancer (UTUC).

INTRODUCTION: The aim was to propose an update of the French Urology Association Cancer Committee (ccAFU) Recommendations on the management of upper urinary tract urothelial carcinomas (UUT-UC). METHODS: A systematic Medline search was performed between 2020 and 2022, taking account of the diagnosis, treatment options and follow-up of UUT-UC, while evaluating the references with their levels of evidence. RESULTS: The diagnosis of this rare pathology is based on CTU acquisition during excretion and flexible ureterorenoscopy with histological biopsies. Radical nephroureterectomy (RNU) remains the gold standard for surgical treatment. Nevertheless conservative treatment can be discussed for low risk lesions: tumour of low-grade, with no infiltration on imaging, unifocal<2cm, eligible for full treatment therefore requiring close endoscopic surveillance by flexible ureteroscopy in compliant patients. After RNU, postoperative instillation of chemotherapy is recommended to reduce the risk of recurrence in the bladder. Adjuvant chemotherapy has shown clinical benefits compared to surveillance after RNU for tumours (pT2-T4 N0-3 M0). CONCLUSION: These updated recommendations should contribute to improving not only patients' level of care, but also the diagnosis and decision-making concerning treatment for UUT-UC.

French AFU Cancer Committee Guidelines - Update 2022-2024: management of kidney cancer.

AIM: To update the recommendations for the management of kidney cancers. METHODS: A systematic review of the literature was conducted from 2015 to 2022. The most relevant articles on the diagnosis, classification, surgical treatment, medical treatment and follow-up of kidney cancer were selected and incorporated into the recommendations. Therefore, the recommendations were updated while specifying the level of evidence (high or low). RESULTS: The gold standard for the diagnosis and evaluation of kidney cancer is contrast-enhanced chest and abdominal CT. MRI and contrast-enhanced ultrasound are indicated in special cases. Percutaneous biopsy is recommended in situations where the results will influence the therapeutic decision. Renal tumours should be classified according to the pTNM 2017 classification, the WHO 2022 classification and the ISUP nucleolar grade. Metastatic kidney cancer should be classified according to the IMDC criteria. Partial nephrectomy is the gold standard treatment for T1a tumours and can be performed by an open approach, by laparoscopy or by robot-guidance. Active surveillance of tumours less than 2cm in size can be considered regardless of the patient's age. Ablative therapies and active surveillance are options in elderly patients with comorbidity. T1b tumours should be treated by partial or radical nephrectomy depending on the complexity of the tumour. Radical nephrectomy is the first-line treatment for locally advanced cancers. Adjuvant treatment with pembrolizumab should be considered in patients at intermediate and high risk for recurrence after nephrectomy. In metastatic patients: Immediate cytoreductive nephrectomy may be offered to oligometastatic patients in combination with local treatment of metastases if this can be complete and delayed cytoreductive nephrectomy can be proposed for patients with a complete response or a significant partial response. Medical treatment should be proposed as first-line therapy for patients with a poor or intermediate prognosis. Surgical or local treatment of metastases can be proposed in case of single or oligo-metastases. The recommended first-line drugs for metastatic patients with clear cell renal carcinoma are the combinations axitinib/pembrolizumab, nivolumab/ipililumab, nivolumab/cabozantinib and lenvatinib/pembrolizumab. Cabozantinib is the recommended first-line treatment for patients with metastatic papillary carcinoma. Cystic tumours should be classified according to the Bosniak classification. Surgical removal should be proposed as a priority for Bosniak III and IV lesions. It is recommended that patient monitoring be adapted to the aggressiveness of the tumour. CONCLUSION: These updated recommendations are a reference that will allow French and French-speaking practitioners to improve kidney cancer management.

A comparison of different established and novel methods to determine horses' laterality and their relation to rein tension.

The present study aimed to assess an agreement between established and novel methods to determine laterality and to identify the distribution of laterality in warmbloods and Thoroughbreds. Nine different methods to investigate a horses' laterality outside a riding context and during riding were compared across two groups of horses (sample A: 67 warmblood- type horses, sample B: 61 Thoroughbreds). Agreement between any two methods was assessed by calculating Cohen's kappa with McNemar's test or Bowker's Test of Symmetry, and the deviation from equal distributions was assessed with chi2-tests. Continuous variables such as rein tension parameters were analyzed using ANOVA or linear mixed models. Generally, laterality test results obtained outside a riding context did not agree with laterality during riding or among each other (Bonferroni corrected p > 0.0018). However, the rider's assessment of her/his horse's laterality allowed conclusions on rein tension symmetry (p = 0.003), and it also agreed substantially with the lateral displacement of the hindquarters (p = 0.0003), a method that was newly developed in the present study. The majority of warmbloods had their hindquarters displaced to the right (73.1%, X2 = 14.3; p < 0.0001). The pattern of lateral displacement of the hindquarters was similar in the Thoroughbred sample (right: 60.7%, left: 39.3%), but did not deviate significantly from an equal distribution (X2 = 2.8; p > 0.05). Laterality seems to be manifested in different ways, which generally are not related to each other. Attention should be paid to the desired information when selecting methods for the assessment of laterality. Horses' laterality has an impact on the magnitude and symmetry of rein tension. Matching horses and riders according to their laterality might be beneficial for the stability of rein tension and thus improve training.

Rein tension in harness trotters during on-track exercise.

Horseracing is under public scrutiny with increasing demands to safeguard horse welfare. It is accepted that, as a result of bit pressure and/or equipment, mouth lesions accompany many types of horse use, including racing. However, there are currently no data available on the range of bit pressures in driven trotters. Our aim was to investigate whether rein tension (RT, proxy for bit pressures) differs among gaits, between tempo within gait, between horses and drivers, and between left/right reins. Standardbreds (n = 9), driven by experienced drivers (n = 11), performed exercise tests on a racetrack (cross-over design; total 31 tests, data available from 26 tests). Horses' motion symmetry was measured before tests (trotting in hand). Rein tension, speed and heart rate were measured during exercise. A moving-window filter was applied to RT raw data. Median, maximum and interquartile range for the estimated stride median RT were determined for each rein (left/right) and segment: walk; circling in slow trot followed by transition to faster trot; fast (racing) trot; and slowing down to walk. Mixed models were used for statistical analysis. Least square means for segment median RT ranged between 17-19 N in walk, 34-40 N during circling-accelerating, 51-62 N in fast trot, and 53-71 N for slowing down. Segment maximum RT was between 60-81 N in walk, 104-106 N during circling-accelerating, 72-86 N in fast trot, and 86-129 N during slowing down. Interquartile ranges were between 7-9 N in walk, 28-31 N during circling-accelerating, 8-10 N in fast trot, and 12-18 N for slowing down. Hind limb asymmetry exceeded the recommended threshold in three horses and was associated with higher median (48 N) and maximum (106 N) RT than symmetric horses (29 N and 73 N, respectively, p < 0.01). Consistent left-right asymmetry in RT was more common among horses than among drivers. Rein tension increased with increasing heart rate (p ≤ 0.0006). Rein tensions were higher than those reported during riding or in horses worked from the ground. The findings of high RT, taken together with the high reported prevalence of oral injuries in harness trotters, call for further research into RT, motion symmetry and use of equipment.