[Organization and risk management in stereotaxic body radiotherapy at the treatment station]. / Organisation et gestion des risques en radiothérapie stéréotaxique au poste de traitement.

The development of stereotaxic body radiotherapy in the last decade has forced the radiotherapy departments to redouble their efforts in the fields of quality and risk management. For this purpose, increasingly complex and rigorous controls of high performance machines as well as a solid team training must be put in place. Extreme hypofractionation requires both increased vigilance at the treatment desk and well-defined and known procedures. The in place organizations contribute to the control of the risks related to the stereotaxic body radiotherapy machines. The medical presence at the beginning of the treatment fractions has been specified as mandatory in a regulatory way since January 2017. This not only ensures security, but also transmits information to the radiation therapy technicians. At the Eugène-Marquis center, the skills of the technicians for stereotaxic body radiotherapy on two dedicated machines (Cyberknife® and Versa HD® Novalis® type) have been upgraded. An accreditation is formalized after a training period and re-evaluated annually. The communication inside and outside the radiotherapy field plays also an important role in maintaining a high level of exchange and sharing of essential information. The means implemented at the Eugène-Marquis center increase the risk control of SBRT, by paying attention to the management of skills at the treatment station.

Interstitial pressure gradients around joints; location of chief resistance to fluid drainage from the rabbit knee.

The hypothesis has been advanced that synovium offers the main resistance to fluid escape from joints, even though it is under 20 microm thick. To test this, fluid was infused into the knee joint cavity of anaesthetised rabbits to set up a pressure gradient, then the profile of periarticular interstitial fluid pressure (P(if)) was measured by advancing a micropipette, connected to a servo-null pressure recorder, in steps through a periarticular tissue 'window' until the joint cavity was entered. With intra-articular pressure (P(j)) raised to 15 cmH(2)O (the pressure of an acute joint effusion) the pressure gradient dP(if) /dx (where x is distance) across the synovial lining was 0.47 +/- 0.04 cmH(2)O microm(-1) (n = 10 joints). This was 23.5-fold greater than the gradient in the subsynovium (0.02 +/- 0.01 cmH(2)O microm(-1); P < 0.0001, Student's t test), indicating that the hydraulic resistivity of the subsynovium is 4 % of that of the synovium. The pressure profile was not altered by circulatory arrest. To test the hypothesis further, the effect of a stab perforation of the synovial lining on fluid drainage rate ((.Q(s)) was studied. Perforation raised both.Q(s) and the conductance term d.Q(s)/dP(j) more than 10-fold (n = 6 joints; P < 0.0001, ANOVA). The results thus support the view that, despite its thinness, the synovial lining offers the main hydraulic resistance to fluid drainage from a synovial joint.

Influence of actin cytoskeleton on intra-articular and interstitial fluid pressures in synovial joints.

Fibroblast microfilamentous actin (F-actin) influences interstitial fluid pressure via linkages to collagen in rat skin (Berg et al., 2001). The present aims were to determine whether the actin cytoskeleton of synovial endothelium, fibroblasts, and synoviocytes influences in vivo (i) fluid exchange between a joint cavity and synovial microcirculation and (ii) extracellular fluid pressures in joints. Rabbit knee joints were treated intra-articularly with the F-actin disrupting drugs cytochalasin D and latrunculin B while joint fluid pressure P(j) was recorded. In joints injected with small volumes of control solution, P(j) fell with time (-0.05 +/- 0.01 cm H2O x min(-1), mean +/- SEM, n = 9, equivalent drainage rate 3.9 microl x min(-1)). Cytochalasin or latrunculin reversed this in approximately 4 min in vivo; P(j) increased with time, e.g., +0.12 +/- 0.04 cm H2O x min(-1) at 200 microM cytochalasin (equivalent filtration rate into joint 6.6-12.5 microl x min(-1), n = 4), with a cytochalasin EC50 of 45 microM. Plasma gamma-globulin clearance into the joint cavity was also increased. Post mortem, cytochalasin did not reverse dP(j)/dt and had no more effect on P(j) than did control solution. Also, when synovial interstitial fluid pressures were measured by servonull micropipette post mortem (control -0.95 +/- 0.37 cmH2O, n = 18) cytochalasin had no significant effect on interstitial pressure over 60 min, even at 1 mM. It was concluded that synovial endothelial F-actin has an important role in the normal synovial microvascular resistance to fluid filtration and plasma gamma-globulin permeation and is thus a potential link between pro-inflammatory mediators and arthritic joint effusions. The results provided no support for the hypothesis that synoviocyte F-actin influences the swelling tendency of synovial matrix and hence extracellular fluid pressures, in contrast to the findings of Berg et al. (2001) in rat dermis.

Isolation of pulmonary interstitial fluid in rabbits by a modified wick technique.

Interstitial fluid protein concentration (C(protein)) values in perivascular and peribronchial lung tissues were never simultaneously measured in mammals; in this study, perivascular and peribronchial interstitial fluids were collected from rabbits under control conditions and rabbits with hydraulic edema or lesional edema. Postmortem dry wicks were implanted in the perivascular and peribronchial tissues; after 20 min, the wicks were withdrawn and the interstitial fluid was collected to measure C(protein) and colloid osmotic pressure. Plasma, perivascular, and peribronchial C(protein) values averaged 6.4 +/- 0.7 (SD), 3.7 +/- 0.5, and 2.4 +/- 0.7 g/dl, respectively, in control rabbits; 4.8 +/- 0.7, 2.5 +/- 0.6, and 2.4 +/- 0.4 g/dl, respectively, in rabbits with hydraulic edema; and 5.1 +/- 0.3, 4.3 +/- 0.4 and 3.3 +/- 0.6 g/dl, respectively, in rabbits with lesional edema. Contamination of plasma proteins from microvascular lesions during wick insertion was 14% of plasma C(protein). In control animals, pulmonary interstitial C(protein) was lower than previous estimates from pre- and postnodal pulmonary lymph; furthermore, although the interstitium constitutes a continuum within the lung parenchyma, regional differences in tissue content seem to exist in the rabbit lung.

[Prolapse of the urethral mucosa in young girls from the Ivory Coast]. / Le prolapsus muqueux de l'urètre de la fillette en Côte-d'Ivoire.

In this retrospective study covering a nine-year period, 65 cases have been analyzed of prolapse of the urethral mucosa in young girls (aged between six weeks and 14 years) from the Ivory Coast. The aim of this study was to describe the etiology of this disorder, and to demonstrate the utility of ambulatory surgery. The main reason for the detection of this disorder was mild genital hemorrhage in 37 cases, which was related to rape in eight instances and to other types of trauma in nine cases, thereby raising serious medico-legal problems. Various forms of treatment were used (medical and/or surgical). The medical approach consisted of antibiotic and antiinflammatory treatment, combined with a local antiseptic. Two surgical approaches were adopted, either the Doria method in which the necrosed tissue is spontaneously eliminated after three to five days, or surgical excision under general anesthesia of the prolapsed mucosa followed by seromucosal stitching. The results were satisfactory in all cases, and in the surgically operated cases no complications or recurrence were noted at one-year follow-up.

Intergranular corrosion-fatigue failure of cobalt-alloy femoral stems. A failure analysis of two implants.

Two modular hip implants with a cobalt-alloy head and a cobalt-alloy stem were retrieved after a fracture had occurred in the neck region of the femoral component, eighty-five and seventy months after implantation. Both implants failed less than one millimeter distal to the taper junction between the head and the stem (outside of the taper). The fracture surfaces of the implant were investigated with the use of scanning electron microscopy, to determine the nature of the failure process. The fractures occurred at the grain boundaries of the microstructure and appeared to be the result of three factors: porosity at the grain boundaries; intergranular corrosive attack, initiated both at the head-neck taper and at the free surface; and cyclic fatigue-loading of the stem. The corrosive attack of the free surface was initiated, in part, by the egression of surface grains and by the ingression of fluid into the intergranular regions. Sectioned surfaces showed extensive intergranular corrosive attack in the prosthetic neck localized in the region of the head-neck taper junction and penetrating deeply into the microstructure.

Simultaneous fractures of the distal radius and scaphoid.

Simultaneous fractures of the distal radius and scaphoid are uncommon injuries for which the treatment is controversial. Nine patients with these fractures are presented. Five patients were available for long-term followup. In the series, there were five Colles and four Smith's fractures of the distal radius. All scaphoid fractures occurred at the anatomic waist. All injuries resulted from falls of considerable force producing hyperextension at the wrist. The ages of the patients ranged from 21 to 90 years (median, 34). All fractures were placed in a thumb spica cast with the wrist in neutral position. Five fractures required a second reduction of the radius and were placed in external skeletal fixation. No scaphoid fracture was displaced by this treatment, and all scaphoid fractures progressed to union. The principal deformity at followup was an average 16 degrees loss of volar tilt. Residual pain or functional disability was not noted. We conclude that these fractures can be successfully treated by reduction of the radius and immobilization by whatever means necessary to maintain an acceptable position. Scaphoid reduction and healing seemed unaffected by the method of treatment used to treat the distal radius fracture in this series.

Stemmed revision arthroplasty for aseptic loosening of total knee replacement.

Fifty-three failed knee replacements were revised using minimally constrained implants with smooth uncemented intramedullary stems and metal-backed tibial components. Polymethylmethacrylate was used only to replace lost bone near the surface of the implant. Excluding four knees which had serious postoperative complications, 91% had successful relief of pain, 84% had over 90 degrees of movement and 80% could walk for more than 30 minutes. Review of the radiographs showed that there were no progressive lucencies at the interface between bone and cement, and no subsidence of components or changes in alignment. At the uncemented stem-to-bone interface, thin white lines developed near the metal, and their significance is discussed. This revision technique is an effective treatment for aseptic failure of primary total knee arthroplasty.

Cementless acetabular replacement using a pegged polyethylene prosthesis.

Acetabular replacement without cement using three types of pegged polyethylene prostheses was begun as a prospective trial by Morscher (August 1977). Ring (June 1979), and Freeman (January 1980); 1878 hips have been replaced using this technique and are reviewed. Follow-up averaged 2 years (range: 6 months-6 years). Successful pain relief and satisfactory walking ability were present in 97% and adequate flexion in 90%. Radiographic review showed the consistent development of a stable, uniform sclerotic line adjacent to the prosthesis. No component migration could be documented. Ten hips have been revised for obvious femoral loosening, and two acetabula showed slight motion during revision for femoral failure and were revised. Deep infection (0.37%) occurred only in patients not receiving perioperative antibiotics and not operated upon in unidirectional filtered air-flow enclosures. Postmortem histological evaluation of eight hips showed a thin fibrous membrane separating the prosthesis from viable bone. These results are preliminary, but nevertheless at least as good as those in any large series of cemented acetabula with the same follow-up. The advantages of this technique are its reproducible results, low complication rate, limited invasion of the skeleton, and easy revision should failure occur.

Freeman-Samuelson total arthroplasty of the knee.

Experience with cementless fixation over the last six years indicates that the technique offers greater opportunities for bone conservation. Thus, when cement is used, and especially if it is forced into the skeleton under pressure, the amount of bone incorporated into the implant is considerable. Conversely, if no cement is used, grafting techniques to fill defects are becoming increasingly routine, so that today no bone may be removed from the replaced knee or hip--all fragments that are excised are repositioned as grafts in defects. Thus, cementless fixation meets the fundamental orthopedic maxim of the conservation of bone stock. Given that an implant can be fixed with satisfactory clinical results without cement and without bone ingrowth, it becomes difficult to demonstrate a clinical advantage for the latter. Nevertheless, bone ingrowth is possible both experimentally and (with less confidence) in man. Thus, it is clearly a technique that should be evaluated. However, it is not, in the senior author's view, a technique that should as yet be generally used. Hopefully, investigations of this problem will take place in a restrained scientific way rather than by the current method, which is in response to the dictates of fashion and commerce.

Isolated fracture of the lesser trochanter in adults: an initial manifestation of metastatic malignant disease.

An avulsion fracture of the lesser trochanter in the absence of known or appropriate antecedent trauma was the initial manifestation of unrecognized metastatic malignant disease in the subtrochanteric area of four patients. In three patients the fracture healed but a pathological subtrochanteric fracture then occurred, and in one patient prophylactic nailing of the hip was performed to prevent this fracture. A thorough search for occult metastatic malignant disease should be made whenever this fracture occurs in an adult. Prophylactic internal fixation to prevent or delay a subsequent pathological subtrochanteric fracture seems worth while.

Ligament injuries associated with physeal fractures about the knee.

A retrospective study of 29 cases of epiphyseal plate fractures about the knee revealed 14 patients with ligament instability at follow-up evaluation an average of 66 months after injury. Distal femoral physeal fractures had occurred in 16 of the 29 patients. Six of these patients had ligament insufficiency, which was recognized by positive anterior drawer and Lachman tests in all six and laxity to valgus stress in one. Proximal tibial physeal fractures were noted in 13 of the 29 patients. Eight of these patients had ligament laxity; anterior drawer and Lachman tests were positive in five, and laxity with valgus stress was present in four patients. It is concluded that because 14 of 29 patients (48%) had ligament insufficiency at follow-up evaluation, physeal fracture about the knee does not exclude ligament damage and, in fact, is associated with a high incidence of ligament injury. Furthermore, a complex proximal tibial physeal fracture associated with medial collateral ligament rupture is described for the first time. This resulted in medial collateral ligament insufficiency, genu valgus, and early degenerative changes. A treatment plan of primary ligament repair, fracture reduction, and follow-up evaluation to skeletal maturity is suggested for this unique fracture.