Respiratory mechanics and gas exchanges in the early course of COVID-19 ARDS: a hypothesis-generating study.

RATIONALE: COVID-19 ARDS could differ from typical forms of the syndrome. OBJECTIVE: Pulmonary microvascular injury and thrombosis are increasingly reported as constitutive features of COVID-19 respiratory failure. Our aim was to study pulmonary mechanics and gas exchanges in COVID-2019 ARDS patients studied early after initiating protective invasive mechanical ventilation, seeking after corresponding pathophysiological and biological characteristics. METHODS: Between March 22 and March 30, 2020 respiratory mechanics, gas exchanges, circulating endothelial cells (CEC) as markers of endothelial damage, and D-dimers were studied in 22 moderate-to-severe COVID-19 ARDS patients, 1 [1-4] day after intubation (median [IQR]). MEASUREMENTS AND MAIN RESULTS: Thirteen moderate and 9 severe COVID-19 ARDS patients were studied after initiation of high PEEP protective mechanical ventilation. We observed moderately decreased respiratory system compliance: 39.5 [33.1-44.7] mL/cmH2O and end-expiratory lung volume: 2100 [1721-2434] mL. Gas exchanges were characterized by hypercapnia 55 [44-62] mmHg, high physiological dead-space (VD/VT): 75 [69-85.5] % and ventilatory ratio (VR): 2.9 [2.2-3.4]. VD/VT and VR were significantly correlated: r2 = 0.24, p = 0.014. No pulmonary embolism was suspected at the time of measurements. CECs and D-dimers were elevated as compared to normal values: 24 [12-46] cells per mL and 1483 [999-2217] ng/mL, respectively. CONCLUSIONS: We observed early in the course of COVID-19 ARDS high VD/VT in association with biological markers of endothelial damage and thrombosis. High VD/VT can be explained by high PEEP settings and added instrumental dead space, with a possible associated role of COVID-19-triggered pulmonary microvascular endothelial damage and microthrombotic process.

Osteotomy and fracture fixation in children and teenagers.

Significant changes have occurred recently in fixation methods following fracture or osteotomy in children and teenagers. Children have benefited the most from these advances. A child's growth is anatomically and physiologically ensured by the growth plate and periosteum. The need to keep the periosteum intact during trauma cases has led to the introduction of flexible intramedullary nailing. We will review the basic principles of this safe, universally adopted technique, and also describe available material, length and diameter options. The problems and the limitations of this method will be discussed extensively. In orthopedics, the desire to preserve the periosteum has led to the use of locking compression plates. Because of their low profile and high stability, they allow the micromovements essential for bone union. These new methods reduce the immobilization period and allow autonomy to be regained more quickly, which is especially important in children with neurological impairment. The need to preserve the growth plate, which is well known in pediatric surgery, is reviewed with the goal of summarizing current experimental data on standard fracture and osteotomy fixation methods. Adjustable block stop wires provide better control over compression. These provide an alternate means of fixation between K-wires and screws (now cannulated) and have contributed to the development of minimally invasive surgical techniques. The aim of this lecture is to provide a rationale for the distinct technical features of pediatric surgery, while emphasizing the close relationship between the physiology of growth, bone healing and technical advances.

[Epidemiology of equestrian injuries in children]. / Les traumatismes liés à l'équitation chez l'enfant, une étude épidémiologique rétrospective de 13 années.

PURPOSE: Children increasingly participate in horseback riding, especially young girls, with more and more accidents during this activity. The severity of the injuries caused by horses seems to be higher than in other sports. METHODS: In a retrospective study, we reviewed 303 accidents of children younger than 15 years of age during the past 13 years. Our study only investigated children who were hospitalized after their accident. RESULTS: Eighty-two percent of the injured children were girls, but there was no difference between girls and boys in terms of severity. In most cases, children were hurt by falling from the horse (87 %). In the other cases, they were kicked or bitten by the animal. The most frequent trauma sustained was fracture (50 %). The upper extremity was injured in 40 % of the traumas followed by the head (32 %). The lower limbs, the abdomen, the spine, or the thorax were injured in less than 10 % of the incidents. The severity of the accidents was studied with the Injury Severity Score and we compared groups of children. Children younger than 11 years old were more severely injured than older children (P=0.0002). CONCLUSION: The youngest horseback riders should be supervised carefully to avoid severe injuries during this activity.

[Aneurysmal bone cyst of the spine in children: a 9-year follow-up of 7 cases and review of the literature]. / Kyste anévrysmal du rachis chez l'enfant: sept cas avec un recul moyen de 9 ans et revue de la littérature.

PURPOSE OF THE STUDY: Aneurysmal cyst is an uncommon benign primitive bone tumor generally observed in young subjects, in a spinal localization in 10% of the cases. We report the clinical, radiological, and therapeutic aspects of seven cases of aneurysmal cyst of the spine. MATERIAL AND METHODS: This series included seven children, mean age 11.7 years (range 8-14) who were followed for 9 years on the average (range 2-24 years). Findings were compared with reports in the literature. RESULTS: Four cysts were located in the cervical spine (C1, C3, C4, C7), two in the thoracic spine (T4, T7) and one in the sacrum. Biopsy-resection was performed in six patients. The sacral cyst was treated by selective arterial embolization. Two complications were observed after surgical treatment. Bony filling of the lesion, evaluated by CT scan six months after surgery, was achieved in five cases, incomplete in two without recurrence of cystic cavities. DISCUSSION AND CONCLUSION: Aneurysmal bone cysts account for 15% of all primitive tumors of the spine. They are more frequent in the cervical and thoracic spine than in a lumbar or sacral localization. One vertebra is involved in most cases, generally the vertebral body and the posterior arch with an asymmetrical extension to one pedicle in some cases. Neurological complications of variable severity are frequent and can be improved by surgical removal of the tumor. CT scan and MRI are the best exams to analyze the spinal cyst, to show bony walls and liquid-liquid levels suggestive of aneurysmal bone cyst, to evaluate the tumor extension and to search for cord compression. When the CT scan and MRI show characteristic signs of aneurysmal bone cyst of the spine, we do not perform a biopsy systematically if complete removal of the tumor appears possible. Surgical removal with biopsy is the treatment of choice. Reconstruction and stabilization of the spine must be complete using bone graft with or without instrumentation. In case of medullary involvement, decompression must be performed rapidly with the most complete tumor removal as possible. Selective arterial embolization can be used in some localizations or as preparation to surgery. Radiotherapy is contraindicated in children because of the risk of radio-induced tumors.

[MacFarland fractures. A series of 24 cases]. / Fractures de Mac-Farland. Etude d'une série de 24 cas.

PURPOSE OF THE STUDY: MacFarland fracture is a joint fracture of the ankle in children. The fracture line passes through the medial part of the lower epiphyseal disk of the tibia. Prognosis is dominated by later risk of malalignment and osteoarthritis. MacFarland fracture usually occurs subsequent to adduction trauma. The aim of this study was to analyze prognosis in a retrospective series of children with MacFarland fractures. MATERIAL AND METHOD: The series included 24 cases (14 boys and 10 girls, mean age at the time of trauma 12.7 years, age range 10-15 years). The fractures were classed into two groups according to the Salter and Harris classification for epiphyseal detachment: Salter 3 (n=4) and Salter 4 (n=20). Surgical treatment was given in 17 cases (11 screw fixations, 4 pin fixations and 2 other ostheosynthesis combinations). Orthopedic care was given in 7 cases (mean immobilization=40 days). All 24 children were followed for a mean 3 years 2 months (3 months=12 years). Three outcome categories were used: good (no pain, stiffness or malalignment), fair (pain and/or stiffness, no malalignment), and poor (malalignment). RESULTS: Overall results were good in 15 cases, fair in 2 and poor in 7 (29 p. 100). Ankle malalignments (7 cases) required surgical correction: epiphysiodesis for varus<5, supramalleolar tibial valgization osteotomy for varus > 5 degrees. After these procedures, outcome was good with a normally aligned painless ankle at 13 months follow-up. Among factors predictive of malalignment (poor outcome), power of the initial trauma (traffic or sports accident in 5 of the 7 poor outcomes), crush injury (medial metaphyseal comminution in two cases which led to varus ankle despite well conducted treatment), fracture type (7 malalignments among the Salter 4 fractures versus none among the Salter 3 fractures), initially defective reduction or osteosynthesis material passing through the epiphyseal disk leading to epiphysiodesis. DISCUSSION: Careful radiologic and clinical surveillance is needed and should be continued to the end of growth (fusion of the tibial cartilage) in children with high risk fractures in order to detect epiphysiodesis early and avoid secondary malalignment. Surgical correction does remain possible and gives good results.

Fractures of the odontoid process: a report of 15 cases in children younger than 6 years.

Fractures of the odontoid process are rare in children. We retrospectively reviewed 15 cases in children younger than 6 years, with an average follow-up of 4 years and 3 months. Eight of these patients had neurologic involvement; magnetic resonance imaging (MRI) changes were seen in the spinal cord at the cervicothoracic junction in six. This neurologic injury was thought to be due to the major anterior displacement of the upper spine, causing spinal cord stretch at the spinal apex of the cervical and thoracic spine. Eight patients secured in forward-facing car seats were injured as the result of motor vehicle accident. Conservatively treated fractures fused without problem. By contrast, the three cases operated on as the initial management of the fracture had complications postoperatively.

Assessment and neurologic involvement of patients with cervical spine congenital synostosis as in Klippel-Feil syndrome: study of 19 cases.

We reviewed 19 children and adolescents with cervical spine congenital synostosis as in Klippel-Feil syndrome (KFS), with an average follow-up of 12.5 years. We paid particular attention to neurologic complications associated with cervical spine abnormalities. Five patients were affected by neurologic complications; four underwent a surgical procedure; and 14 had no neurologic finding. Two had hypermobility at one level, and one had hypermobility at two levels. We found that the more numerous the occipito-C1 abnormalities, the more significant the neurologic risk. In contrast, this risk was not related to the number of "mobile blocks" or to age. Various mechanisms of neural complications have been studied in the literature: medullary abnormality, spinal instability, narrowing of the cervical canal, and vascular dysfunction. Surgery is usually thought to be required in cases with neurologic complications. The indication for surgery is, however, less clear in cases of pure instability without neurologic involvement because surgery is likely to increase the future risks at mobile disks either above or below the fuse level. Careful clinical and radiologic observation is necessary in such patients. Magnetic resonance imaging (MRI) with lateral views in flexion and extension seem to be the best method for detecting impingement of the spine on the cord.

The too-long anterior process calcaneus: a report of 39 cases in 25 children and adolescents.

We observed 39 feet with a "too-long" anteromedial process of the calcaneus (TLAP) in 25 children and adolescents. The abnormality was diagnosed from symptoms (ankle sprains or persistent ankle or foot pain) in 33 cases. Six cases of TLAP were noted on radiographs taken of the patient's opposite, asymptomatic foot. Initial treatment by 3 weeks of strapping failed in seven of seven cases, and 3-6 weeks of primary plaster immobilization failed in 10 of 25 feet. Primary immobilization treatment failed in 17 of 33 symptomatic feet. Resection of the TLAP provided good results in 14 of 15 feet when used as a secondary procedure after failure of immobilization treatment and in one foot in which it was used as primary treatment. We believe that this abnormality is an anatomic variant that becomes symptomatic because of inversion stress with impingement of the abnormally long process between talus and cuboid.

Bone growth after lengthening of the lower limb in children.

Femoral and tibial growth was studied in 6 children undergoing a femoral lengthening and 28 children a tibial lengthening. Growth of both femurs and tibiae was evaluated for 3 years both before and after the procedure. No significant growth disturbance was noted in femoral lengthenings of 14%. However, growth variations were constant after tibial lengthening of 18% on the average and could be correlated to the amount of lengthening. The consequences of these changes are limited in terms of final limb length because overgrowth of the femur often compensates for growth retardation of the tibia when tibial lengthening is less than 18%. Experimental and clinical studies assert that lengthenings of more than 30% can result in significant and definite growth retardation of the lengthened bone.

[Basedow's disease in an adolescent with histiocytosis X]. / Maladie de Basedow chez un adolescent porteur d'une histiocytose X.

BACKGROUND: Immunological dysfunction is known to be present in Langerhans cell histiocytosis; some autoimmune diseases with autoantibodies associated with this condition have already been described. This immunological dysfunction could play a role in the Langerhans cell histiocytosis pathogenesis. CASE REPORT: A 13 year-old boy presented a multifocal bone Langerhans cell histiocytosis associated with Graves' syndrome. This last condition was successfully treated with carbimazole while the focal lesions of histiocytosis did not require any treatment. CONCLUSION: This unique association could be explained by the immunological dysfunction seen in Langerhans cell histiocytosis with secondary appearance of thyreo-stimulating antibodies.

Vertebral growth after thoracic or lumbar fracture of the spine in children.

We studied vertebral growth after thoracic or lumbar fractures in 52 children followed up from the time of fracture until skeletal maturity. We identified pure anterior compression in 32, combined anterior and lateral compression in 11, and total vertical compression in nine. Six patients had no treatment, 42 had a conservative treatment, and four were operated on. In fractures with anterior compression < 10 degrees, no significant difference could be found between the group without treatment and the group with conservative treatment when the Risser sign was 0 or 1 at the time of injury. In such fractures with angles > 10 degrees, conservative treatment gave better results when the Risser sign at injury was < or = 2. Prolonged conservative treatment was not effective in children with a Risser sign of 3. The evolution of lateral compression seems to be related to the initial injury rather than to treatment. Vertical compression injuries were positively influenced by a conservative treatment when the Risser sign was < or = 2.

[Too long antero-medial process of the calcaneus. A study of 59 cases in 37 children and adolescents]. / Processus antéro-interne du calcanéum trop long. Expérience de 59 cas chez 37 enfants et adolescents.

PURPOSE OF THE STUDY: In 1983, we reported 5 cases of a type of tarsal abnormality which often went unrecognized in children and adolescents, the so-called "too long antero-medial process of the calcaneus" (TLAP). This report analyzes 59 such abnormalities observed in 37 children and adolescents. Treatment of the 48 symptomatic cases is presented. MATERIAL: A retrospective study was done on the files of all patients in whom oblique foot radiographs, CT scan or MRI of the foot showed an abnormal antero-medial process of the calcaneus. Of this group, patients were re-examined and radiographs of both feet (AP, lateral and oblique views) were obtained. METHODS: Gender, age at occurrence of symptoms, diagnosis and follow-up, patient complaints and successive treatment were assessed. Final clinical results were graded according to patient's complaints of pain and functional limitation as well as clinical evaluation of subtalar motion. RESULTS: Fifty-nine TLAPs have been found in 37 patients, 30 girls and 7 boys of 11.6 years on average at the first symptoms. Delay of diagnosis from onset of symptoms to final diagnosis averaged 2 years. First symptoms were so-called ankle sprains in 19 patients, ankle instability with tarsal pain in 17, pain and tarsal stiffness in 11, spastic flat foot in 1. In 11 patients, the abnormality was found on the opposite foot. In 2 patients, the TLAP was combined to a calcaneo-navicular bridge of the other foot. Eleven strapping managements resulted in 11 failures, 36 plaster immobilizations led to 12 good, 2 fair and 22 poor results; 25 resections gave 23 good, 1 fair and 1 poor result at a 4.6 years follow-up on average. DISCUSSION: In some people, the antero-medial process of the calcaneus is elongated and becomes interposed between the head of the talus and the cuboïd, far enough to cause impingement on the navicular. Because of the elongation, supination produces a "nutcracker" phenomenon with compression of the process between the talus and the cuboïd; this may result in a chondral injury of the talus head at its inferior and lateral part which faced the TLAP. Authors suggest that calcaneo-navicular coalition and TLAP represent a spectrum of types of errors in embryologie mesenchymal formation with lack of normal joint formation of the tarsal ossicles during fetal life. Immobilization treatment as primary management was particularly unsuccessful in the group with recurrent ankle sprains and persistent pain. Process resection proved a highly successful technique in management of those patients who failed to achieve good results with plaster immobilization. CONCLUSION: The "too long antero-medial process of the calcaneus" should be considered when assessing possible causes of recurrent ankle sprain or persistent tarsal pain in adolescents. An oblique X-ray is usually satisfactory for diagnosis. In patients who failed a conservative management, resection of the process produced good results and painless, supple feet.

Femoral lengthening using the callotasis method: study of the complications in a series of 70 cases in children and adolescents.

The authors reviewed 70 femoral lengthenings performed for limb-length discrepancy in 66 children and adolescents using gradual incremental distraction. Nine were performed using the Judet lengthener and 61, the Orthofix external fixator. Etiology of the femoral shortening was congenital in 22, posttraumatic in 17, postinfection in 13, neurologic in 12, and miscellaneous in six. There were 83 complications, which were assessed as to their relation to the etiology of shortening, amount of lengthening, and age. The incidence of joint complications did not seem to be less than that previously encountered with rapid distraction methods of lengthening. Bony consolidation was achieved without additional surgery in 88% of cases. Delayed consolidation was most commonly encountered in children younger than 8 years old with congenitally short femora. The authors believe that good results can be obtained by incremental distraction by using uniplanar fixation by aggressive physical therapy, proper fixator application, and appropriate dynamization of the fixator.

[Femoral lengthening by callotasis. A study of a series of 79 cases in children and adolescents]. / Alongement de fémur par callotasis. Etude d'une série de 79 cas chez l'enfant et l'adolescent.

PURPOSE OF THE STUDY: Results of femoral lengthening using callotasis method, with particular attention to the complications are presented. MATERIAL AND METHODS: 79 femoral lengthenings performed for limb length discrepancy in 75 children and adolescents were studied. Etiology of the femoral shortening was congenital in 23 cases, post-traumatic in 20, post-infection in 14, neurologic in 13, and miscellaneous in 9. Nine lengthenings were performed using the Judet lengthener and 70 using the Orthofix external fixator. We used gradual incremental distraction (callotasis). RESULTS: Average lengthening achieved was 52 mm (range: 35 to 85), which represented a 17.7 per cent increase in femoral length (range 7.6 per cent to 64 per cent). There were 87 complications, i.e. 110 per cent. Several complications were often encountered during one lengthening, thus, 23 lengthenings (30 per cent) were performed without any complication and 49 (62 per cent) without additional unpredicted operations or anesthesia. All these complications were studied according to the stage (intraoperative, elongation, consolidation and delayed) in which they occurred and to their severity. They were assessed to establish their relationship to etiology of shortening, amount of lengthening and age. Intraoperative complications were rare (2 cases). In the distraction period, joint complications are the most frequent (33 complications), involving the hip 22 times and the knee 11 times; 28 healed without any problems, 14 needed reoperation and 1 dislocation of the hip led to an avascular necrosis. DISCUSSION: The incidence of joint complications did not seem to be less than that encountered with previous methods of lengthening. The author believes that systematic tenotomies performed in order to avoid such complications in congenital short femurs are abusive and have to be discussed case-by-case. Bony consolidation was achieved without additional surgery in 90 per cent of cases. Eight patients had delayed consolidation but did not require surgery. Complicated consolidation was most commonly encountered in children less than 8 years old with congenitally short femurs. The author compared healing time according to the type of dynamization. A significant improvement was found when using a silastic collar (33.3 days/cm) in place of classical dynamization (46.6 days/cm). CONCLUSION: The author believes that good results can be obtained by incremental distraction using uniplanar fixation. Results could be improved by proper fixator application, aggressive physical therapy and well-thought dynamization of the fixator.

[External fixation in fractures of the lower limb in children]. / La fixation externe dans les fractures du membre inférieur de l'enfant.

PURPOSE OF THE STUDY: The indications, morbidity and results of the use of external fixation for fractures of the lower limbs in children is presented. MATERIAL AND METHOD: We studied 72 fractures of the lower limbs (femur: 25; tibia: 47) in 63 children over a seventeen year period. Average age at fracture was 10 yrs 6 mos. (range 4 yrs 5 mos to 14 yrs 6 mos). Forty fractures were open fractures. The indication for external fixation was decided in three different situations: 39 isolated fractures, 11 patients with multiple fractures, and 13 polytraumatized patients. Three different devices were used: Illizarov: 4, Judet: 16, Orthofix: 52. The fixators were left in place until fracture union was demonstrable. RESULTS: Final results were classed into three groups: good, good following reoperation and sequelae. Comparison of the three different series was made using Student's T test. 9 axial deviations or malrotations occurred: 6 times correction was possible with the device in place. Three cases of osteomyelitis occurred at the fracture site. 23 pin tract infections occurred (23 per cent) 5 of which were persistent and 4 required reoperation. The average healing time was different in the three groups: 4.5 mos for isolated fractures: 8.1 mos for multiple fractures and 5.7 mos for polytraumatized patients. Reoperation was required for 4 patients: 2 bone grafts, 1 decortication, 1 bone transport. Ten refractures occurred following removal of the device, 8 times in patients presenting multiple injuries. In 46 patients with a follow-up greater than 18 months, 9 presented an overgrowth between 1 and 2 cm. Following an average follow-up of 2 years 4 months, 7 patients presented sequelae, 56 had good results, 18 following reoperation. DISCUSSION: The use of external fixation remains an irreplaceable method for osteosynthesis of open fractures with severe soft tissue injuries, multiple fractures or in the polytraumatized patient. Some disadvantages such as pin tract infections and refracture following device removal should be taken into consideration before using it for the treatment of simple, isolated closed fractures of the lower limbs in children. CONCLUSION: When external fixation is chosen for treating fractures, it is preferable to use a modular device which allows axial corrections. Local pin site care is essential to prevent early infection. Early weight bearing and dynamization as soon as possible will promote callus mineralization, removal of the device must be progressive and cast protection is recommended.

[Upper metaphyseal lengthening of the tibia. Report of 57 cases in children and adolescents]. / Allongement métaphysaire supérieur du tibia. 57 cas effectués par la méthode du callotasis chez l'enfant et l'adolescent.

INTRODUCTION: The authors reviewed 57 upper metaphyseal lengthenings of the tibia. They especially studied complications in order to evaluate this method. MATERIAL AND METHODS: Fifty seven tibial lengthenings in 47 children and adolescents were reviewed. All lengthenings were performed according to the callotasis technique, using Judet's lengthener in the first 15 cases, the, OF-Garches Orthofix in 42 cases. All the callotasis principles were applied: delayed elongation, 1 mm per day distraction, one month neutralization after elongation period, then dynamization before removing the apparatus. Particularities were: a) metaphyseal osteotomy of the upper tibia, b) screw fixation and osteotomy of the fibula, c) classical dynamization according to De Bastiani and Aldegheri in 29 cases, dynamization by a silastic collar (OF-Dyna-Ring) in 28 cases. METHODS: Severity of complications was classified according to Caton: none, benign, serious (needed reoperation or reanesthesia) and severe (sequel). Complications and rate of lengthenings without complication or with benign complications were studied relative to etiology, age, amount of lengthening and the stage of program in which they occurred. A table summarizes data of all the lengthenings. RESULTS: Lengthening was 52.3 mm in average. Healing time (number of days to lengthen and to fuse the bone divided by the number of lengthened centimeter) was 40 in average (range: 20-105): it was 45.6 days per cm when using classical dynamization and only 34.3 with silastic collar dynamization (p = 0.002). Total of complications was 59 out of 57 lengthenings. 21 complications were benign, 37 serious and 1 severe (partial motor palsy of the foot). Thirty two (56 per cent) lengthenings were performed without unforeseen procedure or anesthesia. There were 4 intra-operative complications: 1 vascular lesion, 1 incomplete osteotomy and 2 malpositioned half screws. Complications of elongation period were the most numerous, 4 transient palsies, 6 knee contractures (2 led to a supracondylar fracture), 6 equinism (4 needed an Achilles tendon lengthening), 12 valgus deviations in which 9 were realigned using OF-Garches fixator without reoperation, 1 serious depression occurred in a bilateral lengthening. Consolidation was achieved without complication in 52 cases. Complications were: 1 refracture (fourth lengthening of the same tibia), 1 delayed union, 1 non-union, 2 late deviations. DISCUSSION: Rate of nervous and joint complications is close to that of other series. However, a high osteotomy decreases the consequences on the foot without increasing knee contracture in flexion. The ability to realign during the elongation period appears to be a prevention of valgus deformity compared to Wagner's technique. The authors's distractor is better tolerated than Ilizarov's. Problems with consolidation are rare, less than 9 per cent of the cases. CONCLUSION: A modular distractor improves the results of tibial lengthening; realignment is possible before, during or after the elongation. OF-Orthofix is easy to apply and well-tolerated by the patient, especially in bilateral lengthenings. Performing a high osteotomy, the callus is thick and the consolidation is quickly achieved and safe. A well-thought dynamization using Orthofix Dyna-Ring decreases the treatment time which is 35 days per centimeter in average.

[Synostosis and tarsal coalitions in children. A study of 68 cases in 47 patients]. / Synostoses et coalitions tarsiennes chez l'enfant. Etude de 68 cas chez 47 patients.

INTRODUCTION: The authors report their experience with tarsal coalitions in children. The purpose of this study was to discuss the origins of the << too long anterior process >> of the calcaneum, and to propose a simple therapeutic strategy for diagnosis and treatment. MATERIALS AND METHODS: The study included 47 children (68 feet), with one or more idiopathic tarsal coalitions. All patients had physical examinations to record symptoms, morphology of the foot, mobility of the foot, gait analysis, standard radiographs, and in some cases CT scans or MRI. The average age of the patients was 11.5 years old, 7 patients had a positive family history for tarsal coalitions. 66 per cent of the patients had mild tarsal pain or a history of repeated ankle sprains. The conservative treatment concerned 28 feet: 3 casts, 2 injections of corticosteroids into the subtalar joint, insole-shoes in 3 cases, and abstention in 20 cases. The operative treatment (40 feet) consisted of resection of calcaneonavicular coalitions (24 feet) resection of talocalcaneal coalitions (3 feet), mediotarsal and subtalar arthrodesis (8 feet), resection of calcaneonavicular coalition combined with the ""Cavalier'' procedure described by Judet (3 feet), calcaneal osteotomy (2 feet). RESULTS: The mean follow-up was 42 months. The morphology of the involved foot was normal in 33 cases, flat foot was seen in 24 cases (4 peroneal spastic flat feet), pes cavus in 3 cases, club foot in 2 cases, pes varus in 4 cases, ""Z'' shaped feet in 2 cases. The radiological examination was demonstrative of tarsal coalition in 61 feet. 7 tarsal coalitions were seen during operative procedures. The location or the coalition was calcaneonavicular (57), talocalcaneal (16), talo-navicular (8), calcaneo-cuboid (7), naviculo-cuneiform (4). The secondary radiographic signs were studied for each foot. In the conservative group, 2 patients degraded their clinical status, one developed a spastic flat foot. In the surgical group, all except 2 patients had good clinical and functional results. One patient had persistent pain in the subtalar joint after a technically correct calcaneonavicular resection. One patient had recurrent spastic flat foot following isolated talocalcaneal resection in a foot presenting multiple tarsal coalitions. This patient was reoperated by a mediotarsal and subtalar arthrodesis with a good result. DISCUSSION: The authors believe that tarsal coalitions have to be recognized based on a history of repeated ankle sprains or subtalar pain. Pain radiographs are diagnostic in most cases. CT scans and MRI are useful when radiographs are negative, especially in young children, or for talocalcaneal coalitions. The authors believe that the ""the too long anterior process'' of the calcaneum in calcaneonavicular coalition has the same embryologic origin. Operative treatment is suitable, when tarsal coalitions are symptomatic or after failure of conservative treatment. Resection gives good results with calcaneonavicular coalitions and selected talocalcaneal coalitions. The mediotarsal and subtalar arthrodesis is suitable in spastic flat foot, or when the bony-bridge is too big, or when the involved joint presents degenerative changes in these cases, the MRI is very useful to select patient for resection or for arthrodesis. CONCLUSION: Evocative history and plain radiographs are diagnostic of most tarsal-coalitions. Modern imagery is useful for difficult diagnostics, for young children, or for evaluation of a joint before resection or arthrodesis. Resection is a good treatment for calcaneonavicular coalitions and gives good results for talocalcaneal coalitions in selected patients.

Distribution of lysophospholipids and metabolism of platelet-activating factor in human follicular and peritoneal fluids.

The distribution of lysophosphatidylcholine, lyso-platelet-activating factor and platelet-activating factor (PAF) was studied in human plasma and in follicular and peritoneal fluid. In plasma, peritoneal and follicular fluids, 51%, 87% and 89%, respectively, of the total lipids were found in the protein fraction (the density > 1.21 fraction). Two forms of lysophospholipids were identified in this fraction: one of high affinity and one of low affinity for albumin. The metabolism of PAF in human follicular fluid, peritoneal fluid and plasma was also investigated. PAF-acetylhydrolase activity was found in both peritoneal and follicular fluids which induced a time-dependent hydrolysis of [3H]PAF. The half-life of PAF was estimated to be 7-12 min in plasma, 15-25 min in peritoneal fluid and approximately 2 h in follicular fluid. PAF-acetylhydrolase activity in embryo culture media supplemented with 10% serum was markedly inhibited by addition of commercial serum albumin. When 25 g albumin l-1 was added, 22% of [3H]PAF was hydrolysed h-1 compared with 72% in media without albumin. The concentrations of lysophosphatidylcholine measured in plasma, in follicular and peritoneal fluids were 252, 286 and 53 mumol l-1, respectively. The distribution of these lysophospholipids and the metabolism of PAF in the female genital tract fluids reported in the present study provide evidence for the involvement of these biologically active lipid mediators in a variety of reproductive processes including sperm-egg interactions and embryonic development.

Embryonic resistance to tumour necrosis factor-alpha mediated cytotoxicity: novel mechanism underlying maternal immunological tolerance to the fetal allograft.

The cytokine tumour necrosis factor-alpha (TNF alpha) has been postulated to play an essential role in the cytotoxic activity of cell-mediated immunity against allogenic or tumour cells invading the host. Several tumour cell lines, however, are resistant to TNF mediated cytotoxicity and respond paradoxically by cellular proliferation and by autocrine secretion of TNF alpha. In view of the metastatic character of the mammalian embryo, the aim of this study was to assess the potential of murine embryos to secrete TNF alpha in vitro, to express TNF receptors and to resist TNF alpha mediated cytotoxicity during their in-vitro development to the blastocyst stage. The potential of human embryos to secrete TNF alpha in vitro until the blastocyst stage was also investigated. From a total of 11 human embryos, which were allowed to proceed to blastocyst formation, seven secreted TNF alpha in the range of 2-117 pg/ml/24 h. A total of 123 C57BL/6J mouse embryos were studied of which 55% secreted TNF alpha in the range of 1.25-3.95 mg/ml/24 h. The presence of high levels of exogenous TNF alpha (10-300 IU) was not detrimental to the in-vitro development of murine embryos. Using immunohistochemical techniques, we were not able to detect the presence of type I or II TNF receptors on the surface of murine embryos. Our findings suggest that human and C57BL/6J murine embryos have the potential to secrete TNF alpha in vitro during the developmental stages leading to blastocyst formation.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of platelet-activating factor, lyso-platelet-activating factor, and lysophosphatidylcholine on sperm motion: importance of albumin for motility stimulation.

OBJECTIVES: To determine the effect of platelet-activating factor (PAF), the PAF derivative lyso-PAF, and lysophosphatidylcholine on in vitro sperm motility and to determine the role of albumin in this interaction. DESIGN: Washed human spermatozoa were exposed to a range of PAF, lyso-PAF, or lysophosphatidylcholine concentrations, supplemented with different albumin concentrations, and the effect on sperm motion was quantified with a computer-assisted motion analysis. The metabolism of these compounds by spermatozoa was also assessed. SETTING: University research laboratory. PATIENTS, PARTICIPANTS: Semen samples were obtained from donors and patients attending an infertility clinic. INTERVENTIONS: Human spermatozoa were incubated with PAF, lyso-PAF, or lysophosphatidylcholine at 10(-11) to 6 x 10(-4) M, with 0% to 1.2% albumin, and motility was evaluated at different time periods from 5 to 240 minutes. Tritiated PAF, lyso-PAF, or lysophosphatidylcholine was incubated with spermatozoa, and the metabolites were separated and quantified by thin-layer chromatography (TLC). MAIN OUTCOME MEASURES: Sperm motion characteristics, including the percentage of motile spermatozoa, velocity, and linearity, and sperm viability were determined. The metabolism of PAF, lyso-PAF, and lysophosphatidylcholine by spermatozoa was also studied. RESULTS: Fifty micromolar of PAF and 100 microM lyso-PAF, supplemented with 0.3% albumin, increased sperm linear velocity by 41% +/- 5% (+/- SEM) and 44% +/- 5% and curvilinear velocity by 17% +/- 3% and 21 +/- 3%, respectively. Lysophosphatidylcholine had a similar effect but only at 22 degrees C and not 37 degrees C. In the absence of albumin, neither PAF, lyso-PAF, or lysophosphatidylcholine induced increases in sperm motion. Lysophosphatidylcholine and lyso-PAF are not detectably metabolized by spermatozoa, whereas 12.5% +/- 1.2% of PAF is hydrolyzed to lyso-PAF in 1 hour. CONCLUSION: Platelet-activating factor, lyso-PAF, and lysophosphatidylcholine independently stimulate sperm linear and curvilinear velocity. This action requires albumin. These compounds may be of use in the treatment of asthenozoospermic males.