Biomedical subjects
Publications and source records attributed to Dennis R Wenger.
Hip impingement is now recognized as a relatively common cause for hip pain in young adults. The early evolution of impingement begins in childhood in several common hip disorders (slipped capital femoral epiphysis, Perthes, early avascular necrosis due to other causes). Recognition and treatment of childhood impingement may prevent the evolution to early hip arthritis.
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Adolescent idiopathic scoliosis is a three-dimensional deformity of the spine. Despite active efforts by different research teams, the etiology of scoliosis remains unclear. Treatment of scoliosis requires a solid understanding of the natural history of the disorder as well as sound clinical judgment. The evaluation, monitoring, and institution of conservative treatment such as bracing can present a challenge to the orthopaedic surgeon. Clinical monitoring is the only intervention necessary in most patients. A detailed review of the patient's history as well as a careful physical examination can help establish the diagnosis and the risk for progression. Skeletal maturity, gender; growth velocity, curve location, and magnitude are factors that can help assess the likelihood of progression. Bracing is the only nonsurgical measure proven to have any effect on halting the progression of scoliosis. Other forms of conservative treatment have not been shown to significantly modify the natural history of idiopathic scoliosis. Bracing results are directly related to compliance with brace treatment; therefore, optimal results cannot be achieved without the patient's cooperation and family support.
Dysplasia epiphysealis hemimelica (DEH), or Trevor's disease, is a rare disorder that most commonly affects the epiphysis of long bones in children. Rarely, major joints such as the hip can be involved. In this paper we describe a successfully treated case involving the acetabulum, documented with multiple imaging modalities, intraoperative photographs, histology, and follow-up radiographs.
OBJECTIVES: Using a synthetic bone model, we investigated changes in the muscle length of the gluteus medius and gluteus minimus following trochanteric osteotomy and pelvic support osteotomy (PSO) and compared the results with those of traditional PSO. METHODS: On two pelvises and four femurs, the lengths of the gluteus medius and gluteus minimus were measured in the following circumstances, with the hips in neutral position and in 45 degrees of flexion: (i) alignment of the hip joint with normal congruency; (ii) dislocated hip joint; (iii) following an osteotomy 2.5 cm below the lesser trochanter and stabilization with an angulation of 45 degrees of abduction; (iv) the insertion point was then moved 2 cm distally and 1 cm laterally, simulating a translation osteotomy of the greater trochanter. RESULTS: The muscle lengths increased with PSO compared to those of the dislocated hips (p<0.0001). Following distal and lateral translation osteotomy, the lengths significantly exceeded those obtained with traditional osteotomy (p<0.002), but were significantly less than those in the neutral position (p<0.001). Measurements in 45 degrees of flexion yielded similar results. Normal lengths could not be obtained in any of the procedures. CONCLUSION: Distal and lateral translation osteotomy following traditional PSO seems to increase the length of the abductor moment arm more than that obtained by traditional PSO alone.
A thorough knowledge of the normal growth and development of the hip, the causes of abnormal development, and the structural and functional changes that result from developmental hip dysplasia and dislocation provide needed information for treating these conditions. Ultrasonography, newborn screening, and radiographic evaluation are important diagnostic tools.
Both nonsurgical and surgical options are available for the treatment of developmental hip dysplasia and dislocation. The advantages, pitfalls, and techniques for using the Pavlik harness should be thoroughly examined before treatment. Other closed and open treatments are aimed at concentric reduction and prevention of residual subluxation and dysplasia. Early diagnosis and treatment lead to the best long-term results for these conditions.
STUDY DESIGN: A retrospective evaluation of 203 adolescent idiopathic scoliosis patients with Lenke 1B or 1C (King-Moe II) type curves. OBJECTIVES: To evaluate the incidence of inclusion of the lumbar curve in the treatment of this type of deformity as well as radiographic factors associated with lumbar curve fusion. SUMMARY OF BACKGROUND DATA: In patients with structural thoracic curves and compensatory lumbar curves, many authors have recommended fusing only the thoracic curve (selective thoracic fusion). Studies have shown that correction of the thoracic curve results in spontaneous correction of the unfused lumbar curve; however, in some cases, truncal decompensation develops. Though there have been various attempts to define more accurately what type of curve pattern should undergo selective fusion, controversy continues in this area. METHODS: Measurements were obtained from the preoperative standing posteroanterior and side-bending radiographs of 203 patients with Lenke Type 1B or 1C curves from five sites of the DePuy AcroMed Harms Study Group. Patients were divided into two groups depending on their most distal vertebra instrumented: the "selective thoracic fusion" group included patients who were fused to L1 or above and the "nonselective fusion" group included patients fused to L2 or below. A statistical comparison was conducted to identify variables associated with the choice for a nonselective fusion. RESULTS: The incidence of fusion of the lumbar curve ranged from 6% to 33% at the different patient care sites. Factors associated with nonselective fusion included larger preoperative lumbar curve magnitude (42 +/- 10 degrees vs. 37 +/- 7 degrees, P < 0.01), greater displacement of the lumbar apical vertebra from the central sacral vertical line, (3.1 +/- 1.4 cm vs. 2.2 +/- 0.8 cm, P < 0.01), and a smaller thoracic to lumbar curve magnitude ratio (1.31 +/- 0.29 vs. 1.44 +/- 0.30, P = 0.01). CONCLUSIONS: The characteristics of the compensatory "nonstructural" lumbar curve played a significant role in the surgical decision-making process and varied substantially among members of the study group. Side-bending correction of the lumbar curve to <25 degrees (defining these as Lenke 1, nonstructural lumbar curves) was not sufficientcriteria to perform a selective fusion in some of these cases. The substantial variation in the frequency of fusing the lumbar curve (6% to 33%) confirms that controversy remains about when surgeons feel the lumbar curve can be spared in Lenke 1B and 1C curves. Site-specific analysis revealed that the radiographic features significantly associated with a selective fusion varied according to the site at which the patient was treated. The rate of selective fusion was 92% for the 1B type curves compared to 68% for the 1C curves.
STUDY DESIGN: A case series of patients with cerebral palsy treated for spinal deformity using Luque-Galveston instrumentation was retrospectively analyzed. OBJECTIVE: To analyze the incidence and risk factors for postoperative loss of sagittal plane correction initially obtained with Luque-Galveston instrumentation in patients with cerebral palsy. SUMMARY OF BACKGROUND DATA: The Luque-Galveston instrumentation technique has been widely adopted in the treatment of neuromuscular spinal deformity. Although the results in the coronal plane have been generally satisfactory, problems in maintaining sagittal plane correction have been noted. METHODS: For this study, 41 patients with spastic quadriplegia who underwent surgical correction of spinal deformity between 1990 and 1998 were reviewed with attention given to the maintenance of sagittal plane correction. Preoperative, initial postoperative, and most recent radiographs were measured to determine the sagittal Cobb angle from T5 to T12, T12 to L2, and L1 to S1. On the basis of the preoperative sagittal alignment, patients were separated into two groups: those with preoperative hyperkyphosis (T5-T12 >or= 50 degrees, T12-L2 >or= 20 degrees, or L1-S1 >or= 0 degrees ) and those with normal or decreased kyphosis. The radiographs were assessed for proximal hardware failure/pullout or junctional kyphosis (>20 degrees ), and for backing out of the Galveston rods distally. RESULTS: Of the 41 patients, 29 underwent correction of their deformity with Luque-Galveston instrumentation alone. In 21 of these patients anterior release-fusion preceded the posterior procedure. Additional anterior lumbar instrumentation was used in 12 patients. Proximal loss of correction or implant failure occurred in 13 patients (32%). In four of these patients junctional kyphosis developed at the cephalad extent of the instrumentation, and nine patients had proximal hardware failure/pullout. Posterior migration of the distal end of the Galveston rods occurred in five patients (12%). Four of these five patients had anterior release and fusion without instrumentation. There were no distal failures in patients for whom anterior lumbar instrumentation was used. All of the patients with distal failure and 11 of 13 patients with proximal failure were considered hyperkyphotic before surgery. The region of hyperkyphosis in the patients that lost distal fixation was most often in the thoracolumbar junction. CONCLUSIONS: Preoperative hyperkyphosis in the thoracic, thoracolumbar, or lumbar spine was associated with an increased incidence of proximal and distal loss of sagittal plane correction in patients with spastic quadriplegic cerebral palsy treated with Luque-Galveston instrumentation alone. An anterior lumbar release and fusion without instrumentation in a patient with thoracolumbar or lumbar kyphosis increased the risk for posterior pullout of the Galveston rods from the pelvis.
Developmental dysplasia of the hip is best treated during infancy. Residual dysplasia is a major cause of disability and should be corrected surgically at an early age. Children 3-8 years of age are usually treated with an acetabular reshaping osteotomy, such as the Pemberton procedure or the San Diego osteotomy. Children over age 8-10 years are best treated using triple innominate osteotomy. After age 14-15 years, when the triradiate cartilage is closed, the Ganz periacetabular osteotomy provides effective correction of residual dysplasia. Surgical intervention during childhood or teenage years can alter the natural history of hip dysplasia and greatly improve hip-joint longevity.
STUDY DESIGN: A retrospective comparison of pediatric patients weighing less than 30 kg who underwent thoracoscopic anterior spinal release and fusion for deformity correction. This group was compared to two control groups: patients weighing over 30 kg (thoracoscopic) and patients under 30 kg (open). OBJECTIVE: To determine the efficacy and safety of thoracoscopic anterior spinal release and fusion in small pediatric patients weighing less than 30 kg. SUMMARY OF BACKGROUND DATA: Recently, thoracoscopic methods have been utilized to perform anterior spinal release/fusion in the treatment of pediatric and adult spinal deformity. The safety, efficacy, and technical challenges of thoracoscopic spinal surgery in small children have not been established. METHODS: "Small thoracoscopic children," defined as those under 30 kg who had thoracoscopic spinal surgery, are the main focus of this study. They were compared to "large thoracoscopic children" (>30 kg, thoracoscopic surgery) and "small open children" (<30 kg, open surgery). Preoperative, intraoperative, and postoperative parameters were analyzed. RESULTS: Small thoracoscopic children (n = 33) had greater estimated blood loss/kg body weight (13.6 mL/kg vs. 6.2 mL/kg; P= 0.003), greater chest tube output (27.5 mL/kg vs. 17.1 mL/kg; P= 0.003), and a longer intensive care unit stay (4.2 days vs. 1.5 days; P= 0.001) than did large thoracoscopic children (n = 48). Conversion to an open thoracotomy occurred in one patient from each of the thoracoscopic groups. Small thoracoscopic children required more anesthesia preparation time (79.2 minutes vs. 64.2 minutes; P= 0.002) than the small open children (n = 25). There was no significant difference in estimated blood loss, chest tube output, or intensive care unit stay between these two groups. Additionally, no significant difference was found between the three groups with regard to the number of discs excised, operative time, and total hospital stay. CONCLUSION: Despite the decreased working space within the chest and difficulties of selective intubation, anterior thoracoscopic surgery for spinal release and fusion can be performed as safely in "small" children as in "large" children; however, additional intraoperative challenges should be anticipated. Although the outcomes were similar in the small thoracoscopic children compared to the small open children, the authors believe that very small patients (under 20 kg) should remain a relative contraindication to thoracoscopic surgery, especially during a surgeon's learning curve.
STUDY DESIGN: A multicenter study examining the association between radiographic and outcomes measures in adolescent idiopathic scoliosis. OBJECTIVES: To evaluate the association between an objective radiographic scoring system and patient quality of life measures as determined by the Scoliosis Research Society outcomes instrument. SUMMARY OF BACKGROUND DATA: Although surgical correction of scoliosis has been reported to be positively correlated with patient outcomes, studies to date have been unable to demonstrate an association between radiographic measures of deformity and outcomes measures in patients with adolescent idiopathic scoliosis. METHODS: A standardized radiographic deformity scoring system and the Scoliosis Research Society outcome tool were used prospectively in seven scoliosis centers to collect data on patients with adolescent idiopathic scoliosis. A total of 354 data points for 265 patients consisting of those with nonoperative or preoperative curves >or=10 degrees, as well as those with surgically treated curves, were analyzed. Correlation analysis was performed to identify significant relationships between any of the radiographic measures, the Harms Study Group radiographic deformity scores (total, sagittal, coronal), and the seven Scoliosis Research Society outcome domains (Total Pain, General Self-Image, General Function, Activity, Postoperative Self-Image, Postoperative Function, and Satisfaction) as well as Scoliosis Research Society outcomes instrument total scores. Radiographic measures that were identified as significantly correlated with Scoliosis Research Society outcome scores were then entered into a stepwise regression analysis. RESULTS: The coronal measures of thoracic curve and lumbar curve magnitude were found to be significantly correlated with the Total Pain, General Self-Image, and total Scoliosis Research Society scores (P < 0.0001). The thoracic and upper thoracic curve magnitudes were also correlated with General Function (P < 0.002). The "coronal" subscore as well as the "total" score of the Harms Study Group radiographic scoring system were also significantly correlated with these Scoliosis Research Society domain and total scores. No radiographic measures taken after surgery were significantly correlated with the postoperative domains of the Scoliosis Research Society outcomes instrument. Stepwise regression analysis of these radiographic measures as predictors of Scoliosis Research Society scores resulted in adjusted R2 values of 0.03-0.07 (P < 0.0001). Although these results show that a significant association exists between the radiographic Cobb angle measure of the scoliosis and the Scoliosis Research Society outcomes scores, the low R2 values indicate that variables other than the radiographic appearance of the deformity (e.g., psychosocial, functional) must also be affecting these scores. CONCLUSION: The Cobb angle measure of the major deformity has a small, but statistically significant, correlation with the reported Total Pain, General Self-Image, and General Function as measured by the Scoliosis Research Society outcomes instrument. None of the radiographic measures in this population correlated with postoperative domain scores of the Scoliosis Research Society outcomes tool.
STUDY DESIGN: A multicenter study of the outcomes of the surgical treatment of adolescent idiopathic scoliosis using the Scoliosis Research Society Questionnaire (SRS 24). OBJECTIVE: To evaluate the patient based outcome of the surgical treatment of adolescent idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: A paucity of information exists with respect to patient measures of outcome regarding the surgical treatment of adolescent idiopathic scoliosis. To our knowledge, no prospective outcome study on this topic thus far exists. METHODS: Using the SRS 24 questionnaire, seven scoliosis centers agreed to prospectively assess outcome for surgically treated patients with adolescent idiopathic scoliosis. Data were collected before surgery and at 24 months after surgery. Data were analyzed using paired and independent samples t test for all seven SRS 24 questionnaire domains (Pain, General Self-Image, Postoperative Self-Image, Postoperative Function, Function From Back Condition, General Level of Activity, and Satisfaction) using Statistical Package for Social Science. The domains were analyzed with respect to the total cohort, gender, curve magnitude, and type of surgery using independent-samples t tests. RESULTS: A total of 242 patients were included in our analysis. A baseline preoperative pain level of 3.68 of 5 was found. This improved to 4.63 after surgery, representing an improvement of 0.95 points. Surgical intervention was associated with improving outcome when compared with preoperative status. Pain, General Self-Image, Function From Back Condition, and Level of Activity all demonstrated statistically significant improvement as compared with preoperative status (P < 0. 001). Overall, patients were highly satisfied with the results of surgery. CONCLUSION: Preoperative pain exists in our adolescent scoliosis population. Pain scores were improved in our study population at the 2-year postsurgical follow-up. Statistically significant improvements were likewise seen in the General Self-Image, Function From Back Condition, and Level of Activity domains. The present study demonstrates the ability of surgery to improve the outcome of patients afflicted with adolescent idiopathic scoliosis.
STUDY DESIGN: A retrospective radiographic review of 31 patients with congenital spine abnormalities who underwent conventional radiography and advanced imaging studies was conducted. OBJECTIVE: To analyze the utility of three-dimensional computed tomography with multiplanar reformatted images for congenital spine anomalies, as compared with plain radiographs and axial two-dimensional computed tomography imaging. SUMMARY OF BACKGROUND DATA: Conventional radiographic imaging for congenital spine disorders often are difficult to interpret because of the patient's small size, the complexity of the disorder, a deformity not in the plane of the radiographs, superimposed structures, and difficulty in forming a mental three-dimensional image. Multiplanar reformatted and three-dimensional computed tomographic imaging offers many potential advantages for defining congenital spine anomalies including visualization of the deformity in any plane, from any angle, with the overlying structures subtracted. METHODS: The imaging studies of patients who had undergone a three-dimensional computed tomography for congenital deformities of the spine between 1992 and 1998 were reviewed (31 cases). All plain radiographs and axial two-dimensional computed tomography images performed before the three-dimensional computed tomography were reviewed and the findings documented. This was repeated for the three-dimensional reconstructions and, when available, the multiplanar reformatted images (15 cases). In each case, the utility of the advanced imaging was graded as one of the following: Grade A (substantial new information obtained), Grade B (confirmatory with improved visualization and understanding of the deformity), and Grade C (no added useful information obtained). RESULTS: In 17 of 31 cases, the multiplanar reformatted and three-dimensional images allowed identification of unrecognized malformations. In nine additional cases, the advanced imaging was helpful in better visualizing and understanding previously identified deformities. In five cases, no new information was gained. The standard and curved multiplanar reformatted images were best for defining the occiput-C1-C2 anatomy and the extent of segmentation defects. The curved multiplanar reformatted images were especially helpful in keeping the spine from "coming in" and "going out" of the plane of the image when there was significant spine deformity in the sagittal or coronal plane. The three-dimensional reconstructions proved valuable in defining failures of formation. CONCLUSIONS: Advanced computed tomography imaging (three-dimensional computed tomography and curved/standard multiplanar reformatted images) allows better definition of congenital spine anomalies. More than 50% of the cases showed additional abnormalities not appreciated on plain radiographs or axial two-dimensional computed tomography images. Curved multiplanar reformatted images allowed imaging in the coronal and sagittal planes of the entire deformity.
BACKGROUND: The goal of operative treatment of hip dysplasia or subluxation in children is to normalize the hip joint to delay or prevent the premature onset of osteoarthritis. In theory, intervention in early childhood, when the remodeling potential is greater, should provide the best opportunity for the development of a normal joint. METHODS: To determine the efficacy of early surgical intervention in restoring the normal morphology of the hip, according to radiographic criteria, we reviewed the cases of thirty-six children (fifty hips) with residual dysplasia or subluxation who were managed with either a femoral and/or a pelvic osteotomy when they were between two and eight years old (Group I). The average age at the time of surgery was 3.7 years, and the average duration of follow-up was 4.3 years. We compared these results with those achieved in fourteen patients (eighteen hips) with residual hip dysplasia or subluxation who were treated surgically at an older age, between eight and eighteen years old (Group II). The outcome was assessed with use of clinical as well as multiple radiographic criteria. We believe that a normal relationship between the acetabulum and the femoral head was established when there was an acetabular index of <20 degrees or a Sharp angle of <42 degrees, a center-edge angle of >20 degrees, and an intact Shenton's line. RESULTS: At the time of the latest follow-up, sixteen of the seventeen hips with residual dysplasia that had been treated with pelvic osteotomy alone in Group I and three of four such hips in Group II had a normal relationship between the acetabulum and the femoral head. Normal radiographic findings were noted in fifteen of the seventeen hips with residual subluxation that had been treated with combined femoral and pelvic osteotomies in Group I compared with four of eight such hips in Group II. CONCLUSIONS: We found that residual hip dysplasia or subluxation could be more predictably corrected, with normal radiographic results and with less morbidity and fewer complications, in children who were between two and eight years old than in those who were between eight and eighteen years old. Long-term follow-up is required to confirm whether the improved anatomy and function of the hip that resulted from early correction of residual dysplasia or subluxation lasts into adulthood.
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An important event in the modern history of pediatric orthopaedics was the establishment of a journal dedicated to the subspecialty in 1981. Twenty-five years' worth of articles within the Journal of Pediatric Orthopaedics was subjected to citation analysis with the intention of identifying the 25 most frequently cited articles. Four true classic articles emerged (>or=100 citations). When looking at all articles on the top 25 list, the most common study design was retrospective in nature, and the most common subject matter was cerebral palsy and trauma-related topics.