J. Richard Bowen

Neurophysiological detection of impending spinal cord injury during scoliosis surgery.

BACKGROUND Despite the many reports attesting to the efficacy of intraoperative somatosensory evoked potential monitoring in reducing the prevalence of iatrogenic spinal cord injury during corrective scoliosis surgery, these afferent neurophysiological signals can provide only indirect evidence of injury to the motor tracts since they monitor posterior column function. Early reports on the use of transcranial electric motor evoked potentials to monitor the corticospinal motor tracts directly suggested that the method holds great promise for improving detection of emerging spinal cord injury. We sought to compare the efficacy of these two methods of monitoring to detect impending iatrogenic neural injury during scoliosis surgery. METHODS We reviewed the intraoperative neurophysiological monitoring records of 1121 consecutive patients (834 female and 287 male) with adolescent idiopathic scoliosis (mean age, 13.9 years) treated between 2000 and 2004 at four pediatric spine centers. The same group of experienced surgical neurophysiologists monitored spinal cord function in all patients with use of a standardized multimodality technique with the patient under total intravenous anesthesia. A relevant neurophysiological change (an alert) was defined as a reduction in amplitude (unilateral or bilateral) of at least 50% for somatosensory evoked potentials and at least 65% for transcranial electric motor evoked potentials compared with baseline. RESULTS Thirty-eight (3.4%) of the 1121 patients had recordings that met the criteria for a relevant signal change (i.e., an alert). Of those thirty-eight patients, seventeen showed suppression of the amplitude of transcranial electric motor evoked potentials in excess of 65% without any evidence of changes in somatosensory evoked potentials. In nine of the thirty-eight patients, the signal change was related to hypotension and was corrected with augmentation of the blood pressure. The remaining twenty-nine patients had an alert that was related directly to a surgical maneuver. Three alerts occurred following segmental vessel clamping, and the remaining twenty-six were related to posterior instrumentation and correction. Nine (35%) of these twenty-six patients with an instrumentation-related alert, or 0.8% of the cohort, awoke with a transient motor and/or sensory deficit. Seven of these nine patients presented solely with a motor deficit, which was detected by intraoperative monitoring of transcranial electric motor evoked potentials in all cases, and two patients had only sensory symptoms. Somatosensory evoked potential monitoring failed to identify a motor deficit in four of the seven patients with a confirmed motor deficit. Furthermore, when changes in somatosensory evoked potentials occurred, they lagged behind the changes in transcranial electric motor evoked potentials by an average of approximately five minutes. With an appropriate response to the alert, the motor or sensory deficit resolved in all nine patients within one to ninety days. CONCLUSIONS This study underscores the advantage of monitoring the spinal cord motor tracts directly by recording transcranial electric motor evoked potentials in addition to somatosensory evoked potentials. Transcranial electric motor evoked potentials are exquisitely sensitive to altered spinal cord blood flow due to either hypotension or a vascular insult. Moreover, changes in transcranial electric motor evoked potentials are detected earlier than are changes in somatosensory evoked potentials, thereby facilitating more rapid identification of impending spinal cord injury.

Multiplier method for predicting limb-length discrepancy.

Background: In patients with a congenital or developmental limb-length discrepancy, the short limb grows at a rate proportional to that of the normal, long limb. This is the basis of predicting limb-length discrepancy with existing methods, which are complicated and require multiple data points. The purpose of our study was to derive a simple arithmetic formula that can easily and accurately predict limb-length discrepancy at skeletal maturity. Methods: Using available databases, we divided the femoral and tibial lengths at skeletal maturity by the femoral and tibial lengths at each age for each percentile group. The resultant number was called the multiplier. Using the multiplier, we derived formulae to predict the limb-length discrepancy and the amount of growth remaining. We verified the accuracy of these formulae by evaluating two groups of patients with congenital shortening who were managed with epiphysiodesis or limb-lengthening. We also calculated and compared the multipliers for other databases according to radiographic, clinical, and anthropological lower-limb measurements. Results: The multipliers for the femur and tibia were equivalent in all percentile groups, varying only by age and gender. Because congenital limb-length discrepancy increases at a rate proportional to growth, the discrepancy at maturity can be calculated as the current discrepancy times the multiplier for the current age and the gender. This calculation can be performed with use of a single measurement of limb-length discrepancy. For progressive developmental (noncongenital) discrepancies, the discrepancy at skeletal maturity can be calculated as the current discrepancy plus the growth inhibition times the amount of growth remaining. The timing of the epiphysiodesis can also be calculated with the multiplier. The predictions made with use of the multiplier method correlated well with those made with use of the Moseley method as well as with the actual limb-length discrepancy in both the limb-lengthening and epiphysiodesis groups. The multipliers derived from the radiographic, clinical, and anthropological measurements of femora and tibiae were all similar to each other despite differences in race, ethnicity, and generation. Conclusions: The multiplier method allows for a quick calculation of the predicted limb-length discrepancy at skeletal maturity, without the need to plot graphs, and is based on as few as one or two measurements. This method is independent of percentile groups and is the same for the prediction of femoral, tibial, and total-limb lengths. The multiplier values are also independent of generation, height, socioeconomic class, ethnicity, and race. We verified the accuracy of this method clinically by evaluating patients who had been managed with limb-lengthening or epiphysiodesis. The method was also comparable with or more accurate than the Moseley method of limb-length prediction.

Adolescent Idiopathic Scoliosis: Treatment with the Wilmington Brace. A Comparison of Full-Time and Part-Time Use*

We reviewed the clinical records and the radiographs of 188 patients who had adolescent idiopathic scoliosis. Our purpose was to determine whether part-time and full-time bracing had been equally effective in preventing progression of the curve. Full-time bracing had been used for ninety-eight patients; part-time bracing, for forty-nine; and electrical stimulation, for forty-one. Eighty-eight patients had had a curve of less than 30 degrees and 100 patients, a curve of 30 to 40 degrees. The treatment was considered a failure if the curve had increased 5 degrees or more. The curve progressed 5 degrees or more in thirteen (36 per cent) of the thirty-six patients who had had full-time bracing for a curve of less than 30 degrees, in thirteen (41 per cent) of the thirty-two who had had part-time bracing for such a curve, and in fourteen (70 per cent) of the twenty who had had electrical stimulation for such a curve. Compared with electrical stimulation, both full-time and part-time bracing prevented progression significantly more effectively (p < 0.02 and p < 0.04, respectively). With the numbers available, the difference in progression between the groups that had had full-time and part-time bracing was not significant (p < 0.18). The curve progressed 5 degrees or more in thirty-six (58 per cent) of the sixty-two patients who had had full-time bracing for a curve of 30 to 40 degrees, in ten of the seventeen who had had part-time bracing for such a curve, and in eighteen (86 per cent) of the twenty-one who had had electrical stimulation for such a curve. The difference in progression between each bracing program and electrical stimulation was significant (p < 0.03 for the full-time program and p < 0.05 for the part-time program). With the numbers available, the difference in progression between full-time and part-time bracing was not significant (p < 1.14).

Diagnostic and therapeutic arthroscopy of the hip in children and adolescents: evaluation of results.

Twenty-four arthroscopies of the hip performed at the Alfred I. duPont Institute, Wilmington, Delaware, in 21 patients between 1981 and 1991 were retrospectively studied. The average age of patients at the time of arthroscopy was 16 years (range, 11-21 years). The arthroscopies were diagnostic if the procedure was performed to visualize the hip or to perform a synovial biopsy and therapeutic if the procedure was performed to treat a suspected intra-articular abnormality. There were eight diagnostic arthroscopies and 16 therapeutic arthroscopies. The arthroscopy correlated with the presumptive causes of symptoms in 13 hips (54%) and failed to correlate in 11 hips (46%). Two patients had complications of transient pudendal nerve dysesthesia with full recovery. There were no infections or residual hip stiffness. A diagnostic arthroscopy is not helpful as a confirming diagnostic procedure. Arthroscopy of the hip is helpful in obtaining synovial biopsies and allows loose body removal, thus obviating the need for open surgery and intraoperative dislocation of the hip.

Lateral Acetabular Growth Stimulation Following a Labral Support Procedure in Legg-Calvé-Perthes Disease

BACKGROUND The main goal of containment treatment in cases of Legg-Calvé-Perthes disease is to prevent hip deformity, which leads to arthritis in adulthood. Recently, the shelf arthroplasty (the labral support procedure) has been proposed as a method of containment. The purpose of the present study was to evaluate growth stimulation of the acetabulum in patients with unilateral Legg-Calvé-Perthes disease by measuring acetabular depth and height following treatment with the labral support procedure. Uninvolved, contralateral hips and hips that were treated with proximal femoral varus osteotomy were used to compare growth. METHODS Sixty-five consecutive patients with unilateral Legg-Calvé-Perthes disease that had been treated with the labral support procedure (forty-nine) or a proximal femoral varus osteotomy (sixteen) were evaluated on the basis of radiographic and clinical data that had been obtained at the time of surgery as well as at one, three, and five years after surgery. Acetabular dimensions (depth, height, and total depth with shelf) were measured and, to eliminate radiographic magnification error, the data were expressed in ratios between the involved and uninvolved sides. RESULTS Preoperatively, both surgical groups were comparable. Acetabular depth indexes at the time of surgery were not different between the groups (p = 0.46). At one, three, and five years postoperatively, the mean depth indexes in the labral support group were significantly higher than those in the proximal femoral varus osteotomy group (F = 5.417, p = 0.001), and trend analysis showed a significant quadratic effect over time in the labral support procedure group (F = 13.132, p = 0.001). The acetabular height indexes at the time of surgery were not different between groups and showed 11% to 13% acetabular overgrowth. The acetabular height indexes in both groups remained unchanged at the time of follow-up (F = 2.82, p = 0.1). The total depth index showed decreasing linear trend values over the period studied (F = 35.115, p = 0.001). CONCLUSIONS Overgrowth of the acetabulum occurs naturally and early in the course of Legg-Calvé-Perthes disease and is more pronounced in terms of height. The labral support procedure induces additional lateral growth of the true acetabulum (excluding the shelf) for three years following surgery, whereas a proximal femoral varus osteotomy does not. Thus, beneficial effects of the labral support procedure are lateral acetabular growth stimulation, prevention of subluxation, and shelf resolution after femoral epiphyseal reossification. LEVEL OF EVIDENCE Therapeutic Level III. See Instructions to Authors for a complete description of levels of evidence.

Growth disturbance of the sternum and pectus deformities: imaging studies and clinical correlation

Background. Radiologic reports of “normal” chest are not uncommon when there clearly are irregularities of sternal ossification and maturation. Analysis of imaging studies of sternal deformities for growth disturbances is not common in the literature and is addressed in this manuscript. Objective. To determine the influence of sternal growth on development of pectus deformities and correlate imaging studies with clinical aspects of different types of these deformities. Material and methods. One hundred forty-one children and adolescents with pectus deformities were evaluated. Sternal growth was estimated through the development of radiographic indices that were available for 57 patients with pectus deformities and for 71 controls. Magnetic resonance imaging of the sternum was performed in two patients to correlate with radiographic information. Results. Radiographic indices of the sternum suggested growth disturbances in three basic types of pectus carinatum deformities: superior, inferior and lateral, and in the localized type of pectus excavatum. Conclusion. Sternal growth seems to have an important influence on the development of carinatum superior; partial influence on carinatum inferior, carinatum lateral, and excavatum localized; and no influence on excavatum wide pectus deformities. The endochondral growth of the sternum and costal arches is an important concept that aids in the interpretation of imaging studies and the orthopedic approach to management of these deformities in children and adolescents.

Severe Tibial Growth Retardation in Total Fibular Hemimelia After Limb Lengthening

Seven patients with total fibular hemimelia who underwent limb-lengthening procedures prior to skeletal maturity were evaluated for tibial and femoral growth after lengthening. The average preoperative follow-up was 6.5 years and all patients were followed to skeletal maturity. Thirteen segments (eight tibiae and five femora) were lengthened by three methods (Wagner, Ilizarov, and modified Ilizarov). The average preoperative limb-length discrepancy was 9.7 cm, and the average projected limb-length discrepancy at skeletal maturity was 12.5 cm. The average tibial lengthening was 6.7 cm (range, 5.3-10) with an average percentage of lengthening of 26% (range, 19-40%). The average postoperative growth rate of the tibia was 80% (range, 70-100%) and of the femur, 83% (range, 70-90%) of the normal side. Five tibiae showed a decrease in the average preoperative growth rate from 82.5% (range, 70-100%) to 39% (range, 26-54%) of the normal side. Two tibiae had no longitudinal growth after lengthening. The average postoperative growth rate of the femur decreased from 83% (range, 70-90%) to 61% (range, 26-125%). In one patient there was an increase in the rate of growth of the femur. These findings suggest that limb lengthening in skeletally immature children with total fibular hemimelia results in severe growth retardation of the tibia after lengthening. The subsequent growth of the tibia after lengthening in patients with total fibular hemimelia is unpredictable.

Modified Woodward procedure for Sprengel deformity of the shoulder: long-term results.

Sprengel deformity of the shoulder is characterized by elevation and medial rotation of the inferior pole of the scapula. Surgical treatment is recommended in significantly involved patients to improve cosmetic appearance and function of the involved shoulder. We report long-term results of a Woodward procedure modified by excision of the prominent superomedial border of the scapula for correction of this deformity in 15 patients. Preoperatively, the total abduction of the shoulder averaged 115 degrees, and on follow-up the abduction had improved to an average of 150 degrees. In all patients except one, there was marked improvement in appearance as assessed on Cavendish scale. All patients except two had achieved skeletal maturity at the last follow-up. Eighty-six percent of patients expressed satisfaction with operative results. Our data support the concept that correction achieved by a modified Woodward procedure is not altered by growth and is maintained beyond skeletal maturity.

Long-Term Follow-up of Female Patients with Idiopathic Scoliosis Treated with the Wilmington Orthosis

BACKGROUND A spinal orthosis is commonly utilized in the nonoperative treatment of idiopathic scoliosis. The purpose of this study was to evaluate the long-term radiographic and functional outcomes of female patients with idiopathic scoliosis who had completed a program of treatment with the Wilmington thoracic-lumbar spinal orthosis. METHODS We retrospectively reviewed the clinical records and radiographs of all female patients who had successfully completed a course of treatment with the orthosis between 1973 and 1983. Ninety-one patients met the criteria for inclusion, and fifty-five women returned for a follow-up evaluation. Their mean age was thirty-one years at the time of follow-up, which was carried out at a mean of 14.6 years after the completion of treatment. The patients were evaluated clinically and radiographically, and they each completed a comprehensive questionnaire assessing their ability to perform twenty-six activities of daily living, their overall physical appearance, the cosmetic appearance of the back, their self-image, and the severity of any back pain. The questionnaire was also administered to a control group of fifty-five women without scoliosis matched for age, number of children, and occupation. RESULTS Seven patients (13%) demonstrated >or=5 degrees of progression of the curve, compared with the curve at the start of treatment, after discontinuing use of the orthosis. No curve progressed >17 degrees compared with the deformity at the time of the initial treatment. There was no significant overall difference between the orthotic treatment group and the control group in terms of back pain, physical activities, functional activities (with the exception of shopping) or self-care activities. As a group, the patients reported significantly greater difficulty with selected positional activities (p = 0.007). Fifty-one (93%) of the fifty-five treated women reported no subjective deterioration in their physical appearance, the cosmetic appearance of the back, or their self-image in the period since they discontinued using the brace. CONCLUSIONS The majority of patients who successfully complete treatment with a Wilmington thoracic-lumbar spinal orthosis for idiopathic scoliosis with an initial magnitude of between 20 degrees and 45 degrees can anticipate that the curve will remain stable into middle adulthood. Any apparent correction of the curve that occurs during treatment can be expected to be lost over time, resulting in a deformity that is equal or nearly equal in magnitude to that measured at the initiation of the orthotic management. Because some patients did demonstrate some progression of the curve by the third or fourth decade of life, it is reasonable to recommend a spinal radiograph during that time to monitor the status of the curve.

Bilateral Legg-Calvé-Perthes disease: presentation and outcome.

Most patients who develop Legg-Calve-Perthes disease have unilateral involvement. For those children who do develop bilateral involvement, the disease and its outcome have not been characterized. This study reviewed the records and radiographs of 83 patients (20 girls and 63 boys) with bilateral Legg-Calve-Perthes disease. The patients were then divided into 3 groups based on the Waldenstrom stage at the time of the first radiograph. In Group I (26 patients), both hips were in the same stage. In Group II (45 patients), the hips were in a different stage. In Group III (12 patients), the first hip was well into the remodeling stage by the time the second hip became affected. Twenty of the 83 patients (24%) were girls. There were significantly more lateral pillar group A hips on the second side than the first side in Groups II and III, and only 10 of the 45 patients (22%) in these groups had more severe disease in the second hip. When compared with data from a group of hips with unilateral involvement, there were significantly more hips with a Catterall group I rating in the patients with bilateral involvement. In general, the Stulberg et al. class assigned appeared to be independent of bilaterality. It appears that the development of bilateral disease is an independent event. The data in the present study do not support that onset of disease in one hip leads to disease or causes a more severe disease in the second hip.