Biomedical subjects
A Kalamchi
Publications and source records attributed to A Kalamchi.
Effects of halothane, enflurane, and isoflurane on somatosensory evoked potentials during nitrous oxide anesthesia.
The effects of 0.5, 0.75, and 1 MAC of halothane, enflurane, and isoflurane in 60% nitrous oxide on somatosensory cortical evoked potentials were studied in 30 patients undergoing corrective surgery for scoliosis. The evoked potentials were averaged at the scalp from the electroencephalogram following repeated bilateral posterior tibial nerve stimulation at the ankle. Latencies and amplitudes of the resulting potentials were measured and compared with the post-induction control values. Graded increase in latencies and graded decrease in amplitudes were found with increasing concentrations of all the three agents (P less than 0.05), confirming that the effects were dose related. Reductions in amplitudes were more marked than increase in latencies. The authors conclude that, during nitrous oxide-based anesthesia, enflurane, and isoflurane resulted in less alteration of somatosensory cortical evoked potentials than halothane. In conjunction with 60% nitrous oxide, 0.5 and 0.75 MAC of halothane, 0.5, 0.75, and 1.0 MAC of isoflurane and enflurane, respectively, were found to be compatible with the generation of waves adequate for evaluation.
Iliofemoral fusion for proximal femoral focal deficiency.
Iliofemoral fusion, as performed for proximal femoral focal deficiency, is designed so that the knee, acting at the level of the triradiate cartilage, will act as the hip. This procedure was indicated in four of our patients to promote fitting of a prosthesis. The results after follow-up of more than five years are reported. Two of the patients also had a Van Nes rotationplasty and two had a Syme amputation. The Syme amputation produced better results. Distal epiphyseodesis of the ipsilateral femur also was performed in three of the four patients to minimize the anterior prominence of the knee. Two patients required a closing wedge osteotomy of the distal part of the femur to improve the alignment. All four patients walked well as functional above-the-knee amputees.
Monteggia fracture-dislocation in children. Late treatment in two cases.
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Congenital deficiency of the tibia.
The late results of treatment of 24 legs in 21 children with congenital deficiency of the tibia are presented. A new classification is proposed which correlates well with recommendations for treatment and with the final functional result. Three types of deficiency were recognised: Type I, total absence of the tibia; Type II, distal absence; Type III, distal deficiency with tibiofibular diastasis. The early radiographic appearances, the functional status of the quadriceps and the severity of flexion contracture of the knee were important factors in the selection of the operations likely to give the best function.
Nuclear magnetic resonance imaging in Legg-Calvé-Perthes disease.
We employed nuclear magnetic resonance imaging in the evaluation of fourteen children with Legg-Calvé-Perthes disease, and found that it accurately identified infarction of the femoral head and, with appropriate techniques, could produce an arthrogram-like image of the hip without the use of ionizing radiation or injection of a contrast agent. Partial saturation-recovery and inversion-recovery pulse sequences with two-dimensional Fourier transformation produced the best results. Nuclear magnetic resonance scanning provides a noninvasive method for the study of the contours of the hip joint, and may give clearer insight into the pathophysiology of infarction and revascularization.
Brief clinical report: dup(4p15 leads to 4pter) in a 19-year-old woman resulting from a maternal 4;14 translocation.
We describe a 19-year-old woman who has a duplication of 4p. The karyotype is 46,XX, - 14, + der(14),t(4;14) (p15;p12)mat in lymphocytes and skin fibroblasts. The patient has coarse hair, prominent forehead and tip of nose, coloboma, scoliosis, and mental retardation.
The fate of the capital femoral physis and acetabular development in developmental coxa vara.
Twenty-two hips in 15 children with the diagnosis of developmental coxa vara were retrospectively reviewed regarding the fate of acetabular development and physeal growth. The relationship of acetabular development to surgical correction of neck-shaft angle and the frequency of plate closure following surgery were investigated. Acetabular depth was found to improve if neck-shaft angle correction exceeded 140 degrees and did not improve if correction was less than 140 degrees. Capital physeal closure occurred in 89% of hips following valgus osteotomy and was not related to physeal injury during surgery. Normal acetabular development is not stimulated by the proximal femoral configuration of coxa vara and will not improve postosteotomy unless adequate valgus correction is achieved. Premature capital femoral physeal closure is a frequent sequelae of valgus osteotomy leading to relative greater trochanteric overgrowth and development of leg length discrepancy.
Modified Salter osteotomy.
A modification of the Salter innominate osteotomy for hip dysplasia was developed. A posterior triangular area is removed from the proximal side of the osteotomy site to allow engagement of the distal iliac segment after displacement of the osteotomized bone. This leads to increased stability and prevents the medial and posterior displacement that occasionally is seen after a Salter osteotomy. Also, with this modification the added limb length seen with the Salter osteotomy is eliminated. Early experience shows that this modification has produced excellent results in patients with unilateral dysplasia and limb-length discrepancy in which the ipsilateral limb is the longer extremity.
Boyd amputations in children.
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The Pavlik harness: results in patients over three months of age.
The role of the Pavlik harness in the treatment of congenital dislocation of the hip in 122 patients over 3 months of age is presented. There were 21 patients with hip dislocation and 101 patients with hip dysplasia, with an average age of 5 months. In patients with dysplasia, concentric reduction in the harness was obtained initially, while it took 1 to 4 weeks to achieve reduction in the dislocated hips. The overall success rate was 97%, with no incidence of avascular necrosis. In three patients, the harness did not succeed in reducing the hips, and alternative methods were used with uneventful course. At follow-up, which averaged 5 years, clinical and radiographic examinations were normal in every patient.
Congenital dislocation of the hip. Open reduction by the medial approach.
In a retrospective clinical review of patients with congenital dislocation of the hip who underwent open reduction through the Ludloff medial approach, stability of reduction, acetabular development and presence of avascular necrosis were evaluated in 11 patients with 15 dislocated hips. This approach was reserved for patients younger than 18 months of age in whom closed reduction had failed. Ten patients with 14 hips underwent preoperative traction. All 15 hips at follow-up or just prior to subsequent surgery displayed dysplastic and insufficient acetabular development, with persistent subluxation in nine hips. Subsequent surgery to obtain better concentric reduction and acetabular coverage was performed in six hips, and further surgery is being considered in four other hips. Ten hips showed signs of avascular necrosis of the ossific nucleus, with additional involvement of the growth plate in four hips. The medial approach resulted in inadequate concentric reduction, with a high incidence of avascular necrosis. In the majority of patients in this small series, a secondary procedure was needed to improve hip stability and the acetabular dysplasia.
Operative management of the resistant clubfoot.
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Congenital hip dislocation and dysplasia in Southern Chinese.
In 1975 we carried out a survey in Hong Kong to locate Chinese children with congenital dislocation of the hip. Analysis of the available records between 1960 and 1975 gave an observed incidence which was at least 10 times less than found in Caucasians. The age and sex distribution, radiographic findings and the left-sided predominance were similar to Caucasians with congenital dislocation of the hip. However, unlike Caucasian children, the Chinese presented with dislocation and not dysplasia. The mothers of children with congenital dislocation of the hip were compared with a control group with normal children to assess their use of the "Hong Kong" position, in which the children are carried on the back of their mother with their hips in a position of wide abduction. Since only half of the children in either group were carried in this manner, other factors must be responsible for the low incidence of congenital dislocation of the hip in southern Chinese.
Avascular necrosis following treatment of congenital dislocation of the hip.
A review of 119 patients with congenital dislocation of the hip complicated by avascular necrosis, of whom fifty-one patients were skeletally mature, showed that damage to the physis was very common. Changes in the secondary ossification center (ossific nucleus) alone were found to be of very little value in predicting the nature of the development of the hip, while the change in the proximal femoral physis was the key to predicting residual deformity. The vascular disturbances were classified into four groups depending on the amount of damage involving the ossific nucleus and the physis during treatment of the dislocation. This classification was found to be accurate in predicting the natural history of avascular necrosis. The more severe forms of avascular necrosis were found to be most prevalent in those patients in whom treatment was begun between birth and the age of six months. We also found that preliminary traction and the use of general anesthesia reduced the incidence of the more severe form of avascular necrosis. The functional results found in the skeletally mature patients coincided with the types of vascular changes; the presence of avascular necrosis enhanced the development of arthritis, especially if residual dysplasia and subluxation also were present.
Congenital deficiency of the fibula.
Ninety-seven limbs, in eighty-one patients, with a diagnosis of congenital deficiency of the fibula have been reviewed. A classification was devised to distinguish the minimal hypoplasia of the fibula (Type I) from the well-known complete absence (Type II). Congenital anomalies of the femur were present in 76 per cent of patients with Type I deficiency and in 59 per cent with Type II. The shortening of the limb was by 13 per cent in Type I and by 19 per cent in Type II, and the percentage shortening was fairly constant during growth. A detailed description of the spectrum of other congenital anomalies was found to be characteristic: for example, the ball and socket formation of the ankle, tarsal coalition and anomalies of the foot. The treatment aimed simply to equalise leg length in Type I deficiency, while amputation of the foot and the fitting of a prosthesis were necessary in Type II to obtain satisfactory function.
Cervical spine abnormalities in neurofibromatosis.
Fifty-six patients with neurofibromatosis were examined for abnormalities of the cervical spine and seventeen of them had demonstrated lesions there. Of the thirty-four patients who had scoliosis or kyphoscoliosis, fifteen (44 per cent) had cervical lesions. Many of the patients with those lesions were asymptomatic. To avoid the complications attributable to the cervical spine, we recommend roentgenographic examination in all neurofibromatosis patients who are about to have general anesthesia or skull traction for treatment of scoliosis.
Posterior subtalar fusion. A preliminary report on a modified Gallie's procedure.
A simple modification of Gallie's subtalar fusion is described as a salvage procedure in treating patients with pain from old fractures of the calcaneous involving the subtalar joint. Graft bone for the fusion is taken from the outer half of the calcaneus, thus avoiding disturbance of the tibia or iliac crest. Collapse of the donor site helps to narrow the widened heel present in these patients. The posterior approach allows the peroneal tendons to be freed from any adhesions, and at the same time release of the calcaneo-fibular ligament permits some correction of the valgus of the heel. The early results in six patients have been encouraging.