Postoperative outcomes for unilateral congenital trochlear nerve palsy: A retrospective cohort study.

PURPOSE: Congenital trochlear nerve palsy is the most common cause of vertical strabismus. The goal of this study was to investigate surgical outcomes after superior oblique tendon plication with or without inferior oblique recession in children and adults with unilateral congenital trochlear nerve palsy. METHODS: Data and outcomes were collected in patients with a diagnosis of unilateral congenital superior oblique palsy during a retrospective single-center study conducted at the University Hospital of Tours. A reproducible, standard ophthalmological and oculomotor examination was performed pre- and postoperatively at 1 year, including presence or absence of diplopia, vertical and horizontal deviations, and compensatory head posture. Surgical success, defined as an endpoint including absence of diplopia in primary position, absence of head tilt, and vertical deviation at distance fixation<5 prism diopters (PD), was analyzed. RESULTS: A total of fifty-seven patients (median [IQR] age of 11 years [5-42]) were analyzed. Patients experienced a significant reduction in vertical distance and near deviations (p<0.001), compensatory head tilt (p < 0.001), and diplopia after surgery (p < 0.001). Surgical success was higher in adults (17/24, 70.8%) than in children (15/33, 45.5%), although this did not reach statistical significance (p=0.0657). CONCLUSION: This study suggests that plication of the superior oblique muscle tendon, with or without recession of the inferior oblique muscle, can be effective in treating unilateral congenital trochlear nerve palsy. Further studies are necessary to compare surgical procedures and investigate their efficacy in adults compared to children in the short and long term.

Position paper on olfactory dysfunction: 2023

BACKGROUND: Since publication of the original Position Paper on Olfactory Dysfunction in 2017 (PPOD-17), the personal and societal burden of olfactory disorders has come sharply into focus through the lens of the COVID-19 pandemic. Clinicians, scientists and the public are now more aware of the importance of olfaction, and the impact of its dysfunction on quality of life, nutrition, social relationships and mental health. Accordingly, new basic, translational and clinical research has resulted in significant progress since the PPOD-17. In this updated document, we present and discuss currently available evidence for the diagnosis and management of olfactory dysfunction. Major updates to the current version include, amongst others: new recommendations on olfactory related terminology; new imaging recommendations; new sections on qualitative OD and COVID-19 OD; updated management section. Recommendations were agreed by all co-authors using a modified Delphi process. CONCLUSIONS: We have provided an overview of current evidence and expert-agreed recommendations for the definition, investigation, and management of OD. As for our original Position Paper, we hope that this updated document will encourage clinicians and researchers to adopt a common language, and in so doing, increase the methodological quality, consistency, and generalisability of work in this field.

Developing a core outcome set for clinical trials in olfactory disorders: a COMET initiative.

STATEMENT OF PROBLEM: Evaluating the effectiveness of the management of Olfactory Dysfunction (OD) has been limited by a paucity of high-quality randomised and/or controlled trials. A major barrier is heterogeneity of outcomes in such studies. Core outcome sets (COS) - standardized sets of outcomes that should be measured/reported as determined by consensus-would help overcome this problem and facilitate future meta-analyses and/or systematic reviews (SRs). We set out to develop a COS for interventions for patients with OD. METHODS: A long-list of potential outcomes was identified by a steering group utilising a literature review, thematic analysis of a wide range of stakeholders' views and systematic analysis of currently available Patient Reported Outcome Measures (PROMs). A subsequent e-Delphi process allowed patients and healthcare practitioners to individually rate the outcomes in terms of importance on a 9-point Likert scale. RESULTS: After 2 rounds of the iterative eDelphi process, the initial outcomes were distilled down to a final COS including subjective questions (visual analogue scores, quantitative and qualitative), quality of life measures, psychophysical testing of smell, baseline psychophysical testing of taste, and presence of side effects along with the investigational medicine/device and patient's symptom log. CONCLUSIONS: Inclusion of these core outcomes in future trials will increase the value of research on clinical interventions for OD. We include recommendations regarding the outcomes that should be measured, although future work will be required to further develop and revalidate existing outcome measures.

Rethinking the 'one-stop' neck lump clinic: a novel pathway beyond coronavirus disease 2019.

OBJECTIVES: UK guidelines advocate 'one-stop' neck lump assessment for cancer referrals. This paper reports the pilot of a novel pre-clinic ultrasound pathway, presents outcomes, and discusses strengths and limitations in the context of the coronavirus disease 2019 pandemic. METHODS: Two-week-wait cancer referral patients with a neck lump were allocated a pre-clinic ultrasound scan followed by a clinic appointment. Demographic, patient journey and outcome data were collected and analysed. RESULTS: Ninety-nine patients underwent ultrasound assessment with or without biopsy on average 8 days following referral. Patients were followed up on average 14.1 days (range, 2-26 days) after initial referral. At the first clinic appointment, 45 patients were discharged, 10 were scheduled for surgery, 12 were diagnosed with cancer, 6 were referred to another specialty and cancer was excluded in 19 patients. Retrospectively, four ultrasounds were performed unnecessarily. CONCLUSION: Pre-clinic ultrasound scanning is an alternative to the one-stop neck lump pathway. This study demonstrates fewer clinic visits, faster diagnosis and a low proportion of unnecessary scans, whilst minimising face-to-face consultations and aerosol-generating procedures.

The COVANOS trial - insight into post-COVID olfactory dysfunction and the role of smell training.

BACKGROUND: Olfactory dysfunction is a cardinal symptom of COVID-19 infection, however, studies assessing long-term olfactory dysfunction are limited and no randomised-controlled trials (RCTs) of early olfactory training have been conducted. METHODOLOGY: We conducted a prospective, multi-centre study consisting of baseline psychophysical measurements of smell and taste function. Eligible participants were further recruited into a 12-week RCT of olfactory training versus control (safety information). Patient-reported outcomes were measured using an electronic survey and BSIT at baseline and 12 weeks. An additional 1-year follow-up was open to all participants. RESULTS: 218 individuals with a sudden loss of sense of smell of at least 4-weeks were recruited. Psychophysical smell loss was observed in only 32.1%; 63 participants were recruited into the RCT. The absolute difference in BSIT improvement after 12 weeks was 0.45 higher in the intervention arm. 76 participants completed 1-year follow-up; 10/19 (52.6%) of participants with an abnormal baseline BSIT test scored below the normal threshold at 1-year, and 24/29 (82.8%) had persistent parosmia. CONCLUSIONS: Early olfactory training may be helpful, although our findings are inconclusive. Notably, a number of individuals who completed the 1-year assessment had persistent smell loss and parosmia at 1-year. As such, both should be considered important entities of long-Covid and further studies to improve management are highly warranted.

A systematic review on diagnostics and surgical treatment of adult right-sided Bochdalek hernias and presentation of the current management pathway.

PURPOSE: Bochdalek hernia is a congenital diaphragmatic hernia. The incidence in adults is estimated around 0.17%. Right-sided hernias are much more seldom than left-sided ones because of faster closure of the right pleuroperitoneal canal and the protective effect of the liver. Due to its rarity, there have been no large prospective or retrospective studies following great need for evidence-based diagnostics and treatment strategies. In this systematic review, we evaluated the current evidence of diagnostics, treatment, and follow-up of adult right-sided Bochdalek hernias. METHODS: According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines a systematic literature review was conducted in PubMed and Cochrane library from 2004 to January 2021. The literature search included all studies with non-traumatic right-sided Bochdalek hernias. Literature on left- or both-sided, pregnancy-associated, pediatric, and other types of hernias were explicitly excluded. Quality assessment of the included studies was performed. RESULTS: Database search identified 401 records. After eligibility screening 41 studies describing 44 cases of right-sided non-traumatic Bochdalek hernias in adulthood were included for final analysis. Based upon the systematic literature review, the current diagnostic, therapeutic, and follow-up management pathway for this rare surgical emergency is presented. CONCLUSION: This systematic review underlined that most studies investigating management of adult non-traumatic right-sided Bochdalek hernias are of moderate to low methodological quality. Hernias tend to occur more frequently in middle-aged and older women presenting with abdominal pain and dyspnea. A rapid and accurate diagnosis following surgical repair and regular follow-up is mandatory. High-quality studies focusing on the management of this rare entity are urgently needed.

A systematic review of facial plastic surgery simulation training models.

OBJECTIVES: The coronavirus disease 2019 pandemic has led to a need for alternative teaching methods in facial plastics. This systematic review aimed to identify facial plastics simulation models, and assess their validity and efficacy as training tools. METHODS: Literature searches were performed. The Beckman scale was used for validity. The McGaghie Modified Translational Outcomes of Simulation-Based Mastery Learning score was used to evaluate effectiveness. RESULTS: Overall, 29 studies were selected. These simulated local skin flaps (n = 9), microtia frameworks (n = 5), pinnaplasty (n = 1), facial nerve anastomosis (n = 1), oculoplastic procedures (n = 5), and endoscopic septoplasty and septorhinoplasty simulators (n = 10). Of these models, 14 were deemed to be high-fidelity, 13 low-fidelity and 2 mixed-fidelity. None of the studies published common outcome measures. CONCLUSION: Simulators in facial plastic surgical training are important. These models may have some training benefits, but most could benefit from further assessment of validity.

An in-depth diagnostic exploration of an inflammation and necrosis syndrome in a population of newborn piglets.

Inflammation and loss of tail integrity can be reasons for serious impairment of animal welfare and one of the major challenges facing modern pig farming. Evidence from practice increasingly suggests that tail lesions might be caused not only by tail biting but also by inflammation and necrosis, which can occur without any action from other pigs. Such changes are not limited to the tail but can also be observed in the ears, heels and soles, claw coronary bands, teats, navel, vulva and face. To describe inflammatory and necrotic manifestations in newborn piglets, all 146 piglets from 11 sows were clinically examined not later than 2 h after birth. In addition, the tail base of 30 randomly selected piglets out of the 146 was histo-pathologically examined as one of the most conspicuously affected body parts. Over 80% of the newborns showed affections in the tail base, claw wall and heels. In 65-87% of the animals, the coronary bands, teats, the face and the ears were affected. None of the 146 piglets was completely free from pathological manifestations. On average, the piglets were affected in six out of nine body parts simultaneously. Histological examinations showed that clear alterations in the skin were already manifested around the time of birth in all examined piglets. Alterations were characterised by the occurrence of numerous lymphocytes and granulocytes throughout the entire subepithelial connective tissue, predominantly in perivascular and perifollicular localisation but also within directly subepithelial glandular ducts and diffusely within the subepithelial connective tissue. In the majority of individuals, the epithelial structure was intact. This concurrence of symptoms in the newborns indicates a primarily endogenous aetiology of an inflammation and necrosis syndrome. Further studies in diverse herd contexts are necessary to establish the conditions for the emergence of such a syndrome and develop welfare indicators.

Improving surgical education in East Africa with a standardized hernia training program.

INTRODUCTION: Inguinal hernias are among the most common surgical diseases in Africa. The current International HerniaSurge Guidelines recommend mesh-based surgical techniques in Low Resource Settings (LRS). This recommendation is currently unachievable in large parts of Africa due to the unaffordability of mesh and lack of appropriate training of the few available surgeons. There is, therefore, a need for formal training in mesh surgery. There is an experience in Hernia Repair for the Underserved in Central and South America, however, inadequate evidence of structured training in Africa. MATERIAL AND METHODS: Since 2016, the aid Organizations, Surgeons for Africa and Operation Hernia have developed and employed a structured hernia surgical training program for postgraduate surgical trainees and medical doctors in Rwanda. This course consists of lectures on relevant aspects of hernia surgery and hands-on training in operating theatres. The lectures emphasize anatomy and surgical technique. All parts of the training were evaluated. Formal pre-course evaluation was conducted to assess the personal surgical experience of the trainees. RESULTS: Over a 3-year period, a structured hernia training programme was employed to train a total of 36 surgical trainees in both mesh and also non mesh hernia surgery. The key principle in this course is the continuous competence assessment and feedback. Evidence is provided to demonstrate improvement in surgical skills as well as knowledge of surgical anatomy which is essential to acquiring surgical competency. With self-assessment, expressed on a Likert scale, the participants could improve the theoretical knowledge about hernias from median 4.4 (on a scale of 1-10) before training to 8.4 after the training. The specific knowledge about anatomy could be improved in the same assessment from 4.8 before training to 8.1. after the training. After training course 12 of the 36 participants (33.33%) were able to carry out both suture- and mesh-based operations of simple inguinal hernias completely and independently. 20 of the 36 participants (55.55%) required only minimal supervision and only four participants (11.11%) required surgical supervision even after the completion of the course. CONCLUSION: We have demonstrated that, medical personnel in Africa can be trained in mesh and non-mesh hernia surgery using a structured training programme.

Are immunosuppressive conditions and preoperative corticosteroid treatment risk factors in inguinal hernia repair?

INTRODUCTION: Immunosuppressive conditions and/or preoperative corticosteroid treatment have a negative influence on wound healing and can, therefore, lead to higher rates of surgical site infections (SSIs) and seromas. For inguinal hernia, no such studies have been carried out to date. METHODS: In an analysis of data from the Herniamed Registry, 2312 of 142,488 (1.6%) patients with primary unilateral inguinal hernia repair had an anamnestic history of an immunosuppressive condition and/or preoperative corticosteroid treatment. Using propensity score matching, 2297 (99.4%) pairs with comparative patient characteristics were formed. These were then compared using the following primary outcome criteria: intra- and postoperative complications, complication-related reoperations, recurrence at one-year follow-up, pain on exertion, pain at rest, and chronic pain requiring treatment at one-year follow-up. Of the 2297 matched pairs with primary unilateral inguinal hernia repair, 82.76% were male patients. 1010 (44.0%) were operated in laparo-endoscopic techniques (TEP, TAPP), 1225 (53.3%) in open techniques (Bassini, Shouldice, Lichtenstein, Plug, TIP, Gilbert, Desarda), and 62 (2.7%) in other techniques. RESULTS: The matched pair analysis results did not identify any disadvantage in terms of the outcome criteria for patients with an anamnestic history of immunosuppressive condition and/or preoperative corticosteroid treatment (yes vs no). In particular, no disadvantage was noted in the rate of surgical site infections (0.65% vs 0.70%; ns) or seromas (1.22% vs 1.57%; ns). The overall rates of postoperative complications were 3.40% vs 4.31% (p = ns) (plus 0.22% concordant events in five matched pairs). CONCLUSION: In primary unilateral inguinal hernia surgery, an immunosuppressive condition and/or preoperative corticosteroid treatment does not appear to have a negative influence on wound complications.

Anosmia as a presenting symptom of SARS-CoV-2 infection in healthcare workers - A systematic review of the literature, case series, and recommendations for clinical assessment and management.

BACKGROUND: Healthcare workers are at the forefront of the ongoing COVID-19 pandemic and are at high risk for both the contraction and subsequent spread of virus. Understanding the role of anosmia as an early symptom of infection may improve monitoring and management of SARS-CoV2 infection. METHODOLOGY: We conducted a systematic review of the literature of SARS-CoV2 infection/COVID-19 and anosmia to help inform management of anosmia in healthcare works. We report a case series of healthcare workers, who presented with a loss of sense of smell secondary to COVID-19 infection to demonstrate management principles. RT-PCR was used to confirm COVID-19 positivity and psychophysical testing of olfaction was performed using the British version of the University of Pennsylvania Smell Identification Test, UPSIT. RESULTS: The systematic literature search returned 31 articles eligible for inclusion in the study and informed our recommendations for clinical assessment and management. All three healthcare professionals who presented with loss of sense of smell subsequently tested positive for SARS-CoV-2. Psychophysical testing of olfaction using the UPSIT confirmed mild and moderate microsmia in two, respectively, and normosmia at day 17 in one. CONCLUSIONS: Olfactory (± gustatory) dysfunction is indicative of COVID-19 infection and thus has important implications in the context of healthcare workers, or key workers in general, who work in close contact with others if not recognised as suffering from COVID. This leads to a potentially higher likelihood of spreading the virus. In conjunction with our literature review these findings have helped with creating recommendations on the assessment and management of olfactory dysfunction during the ongoing COVID-19 pandemic, both for healthcare workers and patients.

Is round ligament varicosity in pregnancy a common precursor for the later development of inguinal hernias? The prospective analysis of 28 patients over 9 years.

PURPOSE: Short-term effects of round ligament varicosity (RLV) in pregnancy have been investigated in small-scale studies. The long-term effects are unknown. This study aims to evaluate the risk of groin hernia manifestation after RLV in pregnancy, to delineate possible risk factors and to analyze the natural course of pregnancy and post-partum period with regard to RLV. METHODS: In a prospective analysis 28 pregnant women with RLV presented to the hernia clinic over 9 years. After clinical and ultrasound examination during pregnancy and publication of early results in 2013 a second structured follow-up was conducted. Demographic data, hernia-specific risk factors, comorbidities, pregnancy and birth-related data as well as post-partum period were documented without loss of follow-up. In these women, all pregnancies that occurred, including the ones without RLV, were analyzed. RESULTS: Median follow-up was 68 months (11.4-104.9). Only one groin hernia was found. No risk factors could be identified. After uncomplicated childbirth complaints subsided spontaneously in all but one patient within 4 weeks. Recurrence rates in subsequent pregnancies are up to 89%. CONCLUSION: Temporary RLV-induced dilation of the deep inguinal ring in pregnancy is not a common precursor for the development of inguinal hernias later in life. All findings support the theory that the hindrance of venous blood flow caused by the gravid uterus is an important contributing factor for RLV in pregnancy, which is self-limited but has a high risk of recurrence and is not an indication for surgery before or after delivery or for cesarean section.

Precostal top-down extended totally extraperitoneal ventral hernia plasty (eTEP): simplification of a complex technical approach.

PURPOSE: Retromuscular mesh augmentation is generally considered to be the ideal technique for repairing ventral hernias and can be performed laparoscopically by 'enhanced view totally extraperitoneal plasty' (eTEP)-a technically complex procedure that requires a high level of surgical expertise. We aimed to develop a simplified technical modification. METHODS: Thirty-one patients with ventral hernias were operated with a modified precostal, top-down eTEP approach, and prospectively recorded in our hernia registry. We describe this novel standardized precostal access and the bilateral development of both retromuscular compartments with a cylindrical dilating balloon port. Demographic-, hernia-specific-, and perioperative data were analyzed retrospectively. RESULTS: Twenty-two primary and 9 incisional hernias with an average defect size of 34.5 cm2 were repaired. An average implant of 420 cm2 always completely covered diastasis recti and/or scars from previous midline laparotomies. Average procedure time was 128 min. One conversion was required due to peritoneal injury. Postoperatively there was one local infection and one patient suffered an interparietal herniation. There were no recurrences during the average 8-month follow-up period. CONCLUSION: With technical modification of precostal access and pneumatic balloon dilation of both retro-rectus compartments, the complex procedure can be simplified through time saving and straightforward unidirectional 'top-down' dissection. The better overview facilitates the crossover for connecting both retro-rectus spaces. In addition, the cranial access allows the anterior- and posterior layers to be closed up to the xiphoid.

Surgical and radiological behavior of MRI-depictable mesh implants after TAPP repair: the IRONMAN study.

PURPOSE: Knowledge of postoperative behavior of mesh implants used for hernia repair is generally limited to cases of recurrence, local complications or return to the previous operative field in other pathological conditions. Previous studies with MRI-visible mesh implants in different parts of the abdominal wall have led to variable findings with regard to mesh properties and mostly described a reduction in size over time with subsequently limited mesh overlap over hernia defects which could contribute to recurrence. We aimed to evaluate implant properties in a mechanically stable anatomical region after TAPP repair of primary unilateral inguinal hernias in men with clinical and MRI examinations 4 weeks and 1 year after surgery. METHODS: From 11/2015 to 01/2019, 23 men with primary, unilateral, inguinal hernias underwent TAPP repair with iron particle-loaded, MRI-visible mesh implants in a prospective cohort study. In 16 patients the operative outcome could be evaluated 4 weeks and 12 months after surgery by clinical examination and MRI evaluation with regard to postoperative course, possible adverse outcomes and radiological findings related to implant behavior-namely MRI-identifiability, mesh dislocation or reduction in surface area. RESULTS: All included patients had an uneventful postoperative clinical course. MRI after 4 weeks revealed one postoperative seroma, which resolved spontaneously. No recurrence was detected. Mesh implants could be accurately delineated in DIXON-IN studies and showed neither clinically nor statistically significant changes in size or position. CONCLUSION: 4 weeks and 1 year after a standardized TAPP procedure the mesh implant used in this study showed no tendency towards dislocation or reduction in size in this anatomical position. Its MRI visibility allows accurate delineation during the postoperative course by experienced radiologists in appropriate MRI protocols. Larger patient series are desirable to further support these findings. Shrinkage of implants in the groin as a reason for early recurrence may be overestimated.

[Impact of mydriatic eyedrops on distance visual acuity in patients with exudative age-related macular degeneration]. / Impact de l'instillation de collyres mydriatiques sur la mesure d'acuité visuelle de loin chez des patients présentant une DMLA exsudative.

PURPOSE: To demonstrate a decrease in distance visual acuity (VA) following instillation of mydriatic eyedrops in eyes with exudative age-related macular degeneration (AMD). MATERIALS AND METHODS: A prospective assessment in clinical practice was conducted in our ophthalmology department at the University Hospital of Tours from 7/19/2018 to 8/29/2018. Distance (ETDRS) and near (Parinaud) VA were assessed before and after instilling one drop each of tropicamide 0.5% and phenylephrine 10% in the 40 included eyes with exudative AMD. RESULTS: The mean difference in distance VA before and after pupillary dilation (PD) was 0.06 LogMAR (SD=0.14) (P<0.01), i.e. -3.05 letters read (SD=7.52) on the ETDRS chart (P=0.01). For near VA, the mean difference was 0.16 LogMAR (SD=0.16) (P<0.001), i.e. -1.58 paragraphs read (SD=1.63) on the Parinaud chart (P<0.001). DISCUSSION: The absence of a clinically significant loss in post-dilation distance VA for exudative AMD could be explained by negligible glare coming from the ETDRS chart, milder photophobia, low pre-dilation VA's and a balance between higher order optical aberrations and diffraction. The opposite result for near VA could essentially be explained by greater glare induced by the light illuminating the Parinaud chart. CONCLUSION: Our primary goal was not achieved. A study presuming the absence of a clinically significant decrease in post-dilation distance VA would be necessary to consider directly measuring post-dilation VA in eyes with exudative AMD in our daily practice.

Retroperitoneal Liposarcoma: A Concern in Inguinal Hernia Repair.

BACKGROUND AND OBJECTIVES: The goal of the study was to evaluate retroperitoneal sarcomas with continuous growth into the scrotum through the inguinal canal with regard to diagnostic approach, surgical treatment, and outcome. The analysis is based on a comprehensively documented case and a complete systematic review of published literature. Potential pitfalls are highlighted. METHODS: We describe the case of a 57-year-old male Caucasian who presented with a swelling in the right groin. Suspecting a scrotal hernia, transabdominal preperitoneal plasty surgery was planned but intraoperatively a large retroperitoneal mass was revealed. After computed tomography scan and magnetic resonance imaging, a complete resection of the tumor was performed. Ten previously published cases describing the same pathology were retrieved from the PubMed database and analyzed systematically in a complete literature review. RESULTS: Histology showed a well-differentiated liposarcoma with tumor-free resection margins. Twenty-two months postoperatively, the patient is in complete clinical remission. CONCLUSION: Preoperative clinical suspicion of retroperitoneal involvement is paramount for developing of a surgical strategy and in unclear cases demands extended preoperative diagnostic workup. Following the appropriate patient management is crucial to prognosis.

Prevalence of an inflammation and necrosis syndrome in suckling piglets.

The current study describes the results obtained from clinical examination of over 4700 suckling piglets from 19 individual herds in Germany. In this cohort the prevalence of inflammation and necrosis in the tails, ears, claw coronary bands, heels and teats was determined using a pre-defined scoring system. Results show that already in the 1st days of life, piglets were affected by inflammation and necrosis of the heels (80%), claw coronary bands (50%) and tail base (20%). The praevalences of these alterations in piglets were influenced by genetics (P <0.001) and age, decreasing gradually in the 2nd week of life (P <0.001). Moreover, a correlation between tail length after tail docking and the prevalence of tail necrosis (P⩽0.04) was found. Tail and ear biting as a behavioural trait was not detected during this study. The early onset, appearance and multiple locations of clinical signs of inflammation and the positive correlation with the genetic background of the piglets may suggest an impairment of the innate immune system by infectious and non-infectious agents. This is in contrast to previously described behavioural abnormalities seen in fattening pigs. Considering the obvious reduction of animal welfare due to the described lesions, there is a need to create awareness among pig farmers and to understand the multifactorial causality involved in this inflammation and necrosis syndrome in piglets.