A micromachined intensity-modulated fiber optic sensor for strain measurements: working principle and static calibration.

This paper describes an intensity-modulated fiber optic sensor for strain measurements. The sensing element is a polydimetilsiloxane (PDMS) micro-diffraction grating, 15 mm long, 2 mm thick, with channels 150 µm wide, spaced apart 200 µm. The working principle of the sensor can be summarized as follows: when the sensing element is strained perpendicularly to the grating plane, light passing through the grating undergoes a modulation caused by the phenomenon of diffraction. Since the grating is interposed between a laser source and a fiber optic, the coupled radiation intensity between these two optical elements can be considered as an indirect measure of strain. A static calibration of the measuring system has been performed, showing that the device, with measuring range of about 0.04, is capable to discriminate strain of 0.005 and it presents a sensitivity increase with strain in the whole range of measurements.

Surgical treatment of spinal deformities in Duchenne muscular dystrophy: a long term follow-up study.

BACKGROUND: Surgical treatment of spinal deformities in Duchenne muscular dystrophy (DMD) is influenced by a number of factors which have proven to be a difficult challenge. Each case should be carefully evaluated, considering not only the natural history of the spinal deformity, but also the patient's general condition. These should be thoroughly assessed through clinical and radiographic investigations together with other medical specialists. Life expectancy should be determined according to the cardio-respiratory function, and both preoperative and postoperative quality of life should be taken into consideration, trying to imagine the functional status of each patient after surgery. METHODS: From February 1985 to February 2000, 58 patients with spinal deformity in DMD were surgically treated. Of 25 patients that were operated on between 1985 and 1995, only 20 were followed-up after 5 years because 5 of them had died during this time. Therefore, the present study focuses on the results obtained in 20 cases. The 20 cases reviewed presented with a mean angular value of scoliosis equal to 48 degrees (range 10-92 degrees). Spinal fusion with our modified Luque technique [6] was performed in 19 cases, whereas CD instrumentation was applied in only one case. RESULTS: At the 5 year follow-up (range 5.6-10 years), the age ranged from 18 to 24 years and averaged 20.4 years. The postoperative angular value of scoliosis averaged 22 degrees (58%, range 0-43 degrees), the mean correction at follow-up was 28 degrees (range 0-60 degrees), and the mean loss of correction was equal to 6 degrees (range, 0-11 degrees). Vital capacity showed a slow progression, slightly inferior to its natural evolution in untreated patients. The severest complication was the death that occurred in one of the patients. CONCLUSIONS: According to the present study, an early surgery (angular value lower than 35-40 degrees) dramatically reduces the rate of risk factors associated with spinal deformities in DMD, and its advantages far exceed the disadvantages, above all in terms of quality of life.

Corrective osteotomy for the treatment of genu procurvatun. Surgery.

The authors present the method known as proximal tibial osteotomy for the treatment of genu procurvatum. The importance of an accurate preoperative study, particularly aimed at avoiding negative repercussions on the position of the patella, and of a correct anatomical exposure with isolation of the peroneal nerve for any iatrogenic lesions, must be emphasized; a condylic plate was used to stabilize osteotomy was stabilized, adapting well to the anatomy of the region, and allowing us to obtain correction of any associated deformities on the frontal plane.

Chondrosarcoma as a complicating factor in Paget's disease of bone.

A 65-year-old male patient with an 8-year history of poliostotic Paget's disease complained of shoulder pain that started 6 months prior to admission. An extensive lytic area was identified in the right proximal humerus along with Paget's disease. There was cortical destruction and a soft tissue mass. Following an incisional biopsy, a diagnosis of grade 2 chondrosarcoma associated with Paget's disease was made. The histologic identification of chondrosarcoma associated with Paget's disease is rare. However, the presence of a calcified matrix in a destructive lesion associated with Paget's disease should alert the radiologist and the pathologist to the possibility of a chondromatous differentiation taking place in the sarcoma associated with Paget's disease. The histologic evaluation of the lesion will form the basis for the diagnosis.

Aneurysmal bone cyst and giant cell tumor of the foot.

From 1950 to 1994, 257 cases of benign bone tumors of the foot were treated at the Bone Tumor Center of the Rizzoli Institute. Aneurysmal bone cysts (ABC) and giant cell tumors (GCT) are rare and often they are misdiagnosed. To define the clinical and radiographic features useful for diagnosis, x-rays of 24 ABCs and 21 GCTs of the foot were reviewed. Adding our series to the cases reported in the literature, the only important clinical data that emerged was the average age of patients affected by ABC and GCT (15 and 27 years, respectively). ABCs localized in small tarsal bones were rare (6%), whereas 19% of GCTs were found in this site. The eccentric, round shape of a lytic lesion was more characteristic of GCT. An aggressive pattern of radiographic bone destruction was observed more frequently in GCT than in ABC (P = 0.01). Septation was seen in both tumors. Typical of ABC was a sharp and trabeculated margin, whereas GCT had an ill-defined edge with normal cancellous bone (P = 0.007). The growth of ABCs often expanded the cortex, while GCTs eroded, thinned, and broke the cortical bone (P = 0.001). A saucerized cortex was observed only in ABCs. A bony shelf was more characteristic of ABC than of GCT (P = 0.002). Pathologic fractures (67%) and joint involvement, evaluated by computed tomography and magnetic resonance imaging (83%), were more frequent in GCTs, whereas fluid levels were more frequently observed in ABCs (47%). The majority of the tumors were stage 2, but GCTs represented 70% of stage 3 aggressive lesions.

Reconstruction by Grosse-Kempf nailing in resections for bone tumor.

The authors report 38 reconstruction by Grosse-Kempf nailing for resection of bone tumor; there were: intercalar resections: 16; arthrodeses of the knee: 13; arthrodesis of the ankle joint: 5; gyroplasty: 4. Massive homoplastic bone graft was used in 26 cases, in 3 of which autoplastic grafting was associated; autoplastic grafts were used exclusively in 7 cases, and a cement spacer was used in 1. Twenty-nine patients (76%) obtained satisfactory final results, but in 10 cases secondary surgery was performed for a total of 14 operations, of which 7 major (1 nail substitution and 6 vascularized fibula operations). There were 7 failures: mechanical complications: 6; infection: 1. The highest number of non-unions were observed where massive homoplastic grafting was used: intercalar reconstruction: 11; arthrodesis of the knee: 7. The results were evidently better and the incidence of complications low in cases in which autoplastic grafting was used or where gyroplasty was performed. Absolute stiffness and best possible contact are difficult to obtain with blocked intramedullary nailing. On the contrary, when autoplastic grafts are used or when gyroplasty is performed micromovements allowed the instrumentation are compatible with good consolidation.

Intramedullary osteosynthesis with Grosse-Kempf nailing for the treatment of distal fractures of the femur.

The authors report the results they obtained in a homogeneous series of fractures of the distal third of the femur treated by Grosse-Kempf nailing. Of the 67 fractures (58 closed, 9 exposed) treated with closed surgery (except for 1 case treated by nailing 35 days after trauma) non-union was never observed. The two cases of delay in consolidation (one related to an infection) did not require a change in method. Bone grafting was never necessary. Only in 3 cases (2 with multiple trauma, 1 treated by open reduction) was moderate reduction in range of movement of the knee observed.

Radiographic and therapeutic aspects of neurogenic arthropathy.

The authors describe the typical radiographic aspects of neurogenic arthropathy based on an examination of 127 cases observed at the Rizzoli Orthopaedic Institute. Surgical indications for the various joints affected are discussed, and the results obtained after treatment are reported.

The use of viral culture and p24 antigen testing to diagnose human immunodeficiency virus infection in neonates. The HIV Infection in Newborns French Collaborative Study Group.

BACKGROUND: Early diagnosis of human immunodeficiency virus (HIV) infection in infants born to infected mothers is important for the infants' medical care, but the presence of maternal antibodies makes serologic tests uninformative. METHODS: In a cohort study of 181 infants born to HIV-infected mothers, we assessed the diagnostic value of HIV viral culture and testing for the presence of p24 antigen. The infants were tested at birth, again during the first 3 months, then followed and tested at the age of at least 18 months. RESULTS: Of the 181 infants, 3 died of HIV infection and 37 were seropositive after the age of 18 months. Viral cultures at birth were positive in 19 of the 40 infected infants and in none of the uninfected infants, yielding a sensitivity of 48 percent (95 percent confidence interval, 32 to 63 percent) and a specificity of 100 percent (95 percent confidence interval, 97 to 100 percent). By the age of three months, 30 of the 40 infants (75 percent) had positive cultures; again, there were no false positive results among the infants who were tested a second time, of the 141 who remained uninfected. The sensitivity of testing for p24 antigen at birth was only 18 percent, with a specificity of 100 percent. The presence of p24 antigen at birth was associated with the development of early and severe HIV-related disease (P less than 0.04). CONCLUSIONS: Viral culture at birth can correctly identify about half of newborns with HIV infection. The fact that this usually sensitive technique fails to identify about half the ultimately infected neonates suggests that vertical transmission of HIV may occur late in pregnancy or during delivery.

Grosse-Kempf nailing in fractures of the tibia.

A series of 136 tibial fractures treated with locked Grosse-Kempf nailing is reviewed, evaluating the results according to rapidity of healing, functional recovery, and complications. Locked nailing proved so reliable that immediate mobilization was possible. There was only a 6% incidence of delayed union, including infections (3 cases, 2%) and nail breakage (2 cases, 1.5%). Several details of the operative technique that were decisive in the final result are discussed.

Syringomyelic arthropathy: a description of two cases and a review of the literature.

Neurogenous arthropatHy is a rare disease. Nonetheless, every orthopaedist will sooner or later be faced with the arthropathy before the neurologic disease has been diagnosed. The authors report their study on two cases of syringomyelic arthropathy, repropose its anatomopathological, clinical and radiographic features, and discuss the etiopathogenesis, differential diagnosis and treatment of the disease.

An evaluation of the "quoad vitam" prognosis in the elderly patient with medial fracture of the femoral neck.

The authors analyzed 425 consecutive cases of medial fracture of the femoral neck with the purpose of establishing a simple and practical system, and one which is easy to use, in order to evaluate this type of lesion and to compare different series of cases. Based on these criteria the death rate occurring intra-hospital and 6 months after trauma, the influence of the age factor, the type of anesthesia used and the type of treatment carried out, were evaluated. The results were as follows: The classification devised by the American Society of Anesthesiology continues to be an effective system for the evaluation of vital risk. The death rate was always directly related to age, and it was not influenced by either the type of anesthesia or the type of surgery used; however, it doubled when non-surgical treatment was used.

Acute external capsuloligamentous lesions of the knee.

The authors discuss 18 cases of acute capsuloligamentous lesions of the external compartment of the knee submitted to surgical treatment. The results obtained by separately studying the progression of the various types of anatomical lesions revealed a relationship between the entity of the lesion and the results. Positive results were as follows: 100% in isolated lesions of the EC, 70% in lesions of the EC and ACL, 40% in lesions of the EC + ACL + PCL. In grade I distorsion trauma surgery is not indicated; in grade II lesions treatment is based on an objective examination in narcosis, and surgery should be performed when dynamic tests are positive; in grade III lesions surgery is always indicated. An objective examination in narcosis (rarely arthroscopy) is thus of essential importance to therapeutic indications.

Grosse-Kempf nailing in the elderly.

The authors report on 30 fractures of the femur and tibia treated with the Grosse-Kempf locked nail in patients aged more than 60 years. Neither nonunion nor severe complications were observed; surgical trauma was well sustained. Functional results were particularly satisfactory; most patients began walking within the first week after fixation.

Paternal age and mental functions of progeny in man.

The effects of maternal age on the quality of offspring are well known. Those due to the father's age are less obvious, apart from the role of increasing paternal age in the onset of many dominant autosomal disorders. But an experimental model has demonstrated that, in rats, increasing paternal age, without any other anomalies, might produce a decreased learning capacity in progeny. The object of the epidemiological investigation presented here was to verify whether this effect might also occur in man. The study involved the distribution of scores obtained in psychometric tests by 18-year-old male subjects, according to their father's age at the time of their birth. This distribution indicated not only that increasing paternal age is accompanied by effects similar to those observed in animals, but also that very young paternal age was also related to these effects. Thus, the curve of such scores produced an inverted U-shape, with maximum scores obtained when the father was about thirty years of age. Maternal age did not appear to play a part in this event. These results pose the problem of identifying genetic and/or psychosocial factors which might have an impact on the quality of the conceptus.

Problems related to blocked nailing in fractures of the proximal femur.

The modern treatment of fractures of the proximal femur in the adult usually involves surgery. Open plating has proved to be reliable, but often involves a high percentage of complications: axial deformity, delayed union, breakage of the plate and/or screws (the risk of which increases in relation to the degree of comminution). At this site, in fact, the plate is submitted to strong flexion stress. It therefore becomes essential to associate cancellous grafts (as proposed by the AO School) (Muller et al., 1981) or a homoplastic cortical craft (as in our experience) (Zinghi and Masetti, 1982). Furthermore, open osteosynthesis is time consuming and this means considerable blood loss and a risk of infection. There are thus many reasons for preferring closed surgery, but effective stabilisation can only be obtained with blocked nailing; in fact, only metadiaphyseal screwing is capable of neutralising the rotation or axial stresses which cause deviation, instability or telescoping of the fracture (Kempf et al., 1978; Tigani et al., 1986; Zinghi et al., 1984). Osteosynthesis with Grosse-Kempf nailing is thus an effective alternative to open nailing, particularly in those fractures which would require additional bone grafting with this method. The purpose of our study was to verify the effectiveness of intramedullary osteosynthesis with Grosse-Kempf blocked nailing, in particular analysing the problems encountered in the use of this method.

A prospective study of infants born to women seropositive for human immunodeficiency virus type 1. HIV Infection in Newborns French Collaborative Study Group.

Assessment of the risks of transmission of infection with human immunodeficiency virus type 1 (HIV-1) from mother to newborn is difficult, partly because of the persistence for up to a year of maternal antibodies transmitted passively to the infant. To determine the frequency of perinatal transmission of HIV infection, we studied from birth 308 infants born to seropositive women, 62 percent of whom were intravenous drug abusers. Of 117 infants evaluated 18 months after birth, 32 (27 percent) were seropositive for HIV or had died of the acquired immunodeficiency syndrome (AIDS) (n = 6); of the 32, only 2 remained asymptomatic. Another 76 infants (65 percent) were seronegative and free of symptoms, whereas 9 (8 percent) were seronegative but had symptoms suggestive of HIV-1 infection. The infants infected with HIV-1 did not differ from the others at birth with respect to weight, height, head circumference, or rate of malformations, but as compared with newborns who were seronegative at 18 months, their serum IgM levels were higher (78 +/- 81 mg per deciliter vs. 38 +/- 39 mg per deciliter; P less than 0.03) and their CD4 lymphocyte counts were lower (2054 +/- 1221 per cubic millimeter vs. 2901 +/- 1195 per cubic millimeter; P less than 0.006). Neither maternal risk factors nor the route of delivery was a predictor of seropositivity at 18 months; however, 5 of the 6 infants who were breast-fed became seropositive, as compared with 25 of 99 who were not (P less than 0.01). We conclude that approximately one third of the infants born to seropositive mothers will have evidence of HIV-1 infection or of AIDS by the age of 18 months, and that about one fifth of this group will have died.

Correlation between defects in chromatin condensation of human spermatozoa stained by aniline blue and semen characteristics.

Human sperm heads which present disturbances of chromatin condensation are stained by acidic aniline, blue. To determine whether the proportion of unstained heads, i.e. with well condensed chromatin, can be considered as an index of sperm quality, a study was undertaken in 157 men during an infertility evaluation. In addition to the usual sperm characteristics, the percentages of unstained heads and of morphologically normal and abnormal forms were concomitantly evaluated. In a total of 15760 spermatozoa, the percentage of unstained heads was much higher in the population of morphologically normal forms than in that of abnormal forms (79.1% and 49.4% respectively, p less than 10(-9]. Among spermatozoa with structural abnormalities, it was much higher in cells with a single anomaly than in those with associated anomalies (53.9% and 40.6% respectively, p less than 10(-9]. When morphology was taken into account, only vitality was found to vary significantly with the percentage of unstained heads.