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Biomedical subjects

M B Millis

Publications and source records attributed to M B Millis.

At least 19 recordsLinked to original sources
PubMed2005

Periacetabular osteotomy in patients with Down's syndrome.

We treated eight dysplastic acetabula in six skeletally mature patients with Down's syndrome by a modified Bernese periacetabular osteotomy. The mean age at the time of surgery was 16.5 years (12.8 to 28.5). Mean length of follow-up was five years (2 to 10.4).Pre-operatively the mean (Tonnis) acetabular angle was 28 degrees, the centre-edge angle was -9 degrees, and the extrusion index was 60%; post-operatively they were 3 degrees, 37 degrees, and 17%, respectively. Two patients with post-operative (Tonnis) acetabular angles > 10 degrees developed subluxation post-operatively and required secondary varus derotation femoral osteotomies. Another patient developed a late labral tear which was treated arthroscopically. All eight hips remain clinically stable, and are either asymptomatic or symptomatically improved. These results suggest that the modified Bernese periacetabular osteotomy can be used successfully in the treatment of acetabular dysplasia in patients with Down's syndrome.

Acetabulum↗
PubMed2001

Wagner multiple K-wire osteosynthesis to correct coxa vara in the young child: experience with a versatile 'tailor-made' high angle blade plate equivalent.

In 1978, Wagner described a technique using multiple Kirschner wires (K-wires) to stabilize an intertrochanteric osteotomy performed for the correction of coxa vara in small children. Multiple K-wires are used to create a custom high-angle blade plate for valgus osteotomy. The authors have evaluated a retrospective series of 17 Wagner intertrochanteric osteotomies that were performed in 10 children with coxa vara between the ages of 1 year and 8 years. The neck-shaft angle was corrected from 93.5 degrees to 129.5 degrees at long-term follow-up, and the Hilgenreiner epiphyseal angle was corrected from 71 degrees to 37.6 degrees at long-term follow-up. Revision surgery was performed on five hips with inadequate initial surgical correction. Complications included a single broken K-wire, a femur fracture after hardware removal, and one hip developed avascular necrosis postoperatively.

Bone Diseases, Developmental↗
PubMed2000

[Computer-assisted planning of corrective osteotomies in cases of epiphysiolysis capitis femoris].

Slipped capital femoral epiphysis (SCFE) leads to an unphysiologic function in adolescent hips. Evaluation of the slippage as well planning of corrective osteotomies is a major three-dimensional (3D) problem. Therefore, the current clinical evaluation, which is based on biplanar plain radiographs, cannot be satisfying. More is needed than simply measuring the femoral geometry to evaluate the impact of a slippage onto the physiologic hip function. We have developed a computer-based system for planning and evaluation of reorienting osteotomies in severe cases of SCFE. In our system, CT-based 3D computer models of the hip are used to simulate the range of motion within physiologic cartilage-to-cartilage contact. This helps to visualize and quantify the early impingement due to the slippage. In addition, 3D techniques allow to simulate and plan the corrective osteotomy in an intuitive way on the computer screen. Using the same range of motion system mentioned above, the projected result can be evaluated quantitatively and compared to other approaches. The motion simulation is based on the surface geometry of the joint partners rather than on a predefined, fixed rotation center. The presented system allows a much more intuitive and appropriate system for indicating and planning corrective osteotomies than conventional methods.

Adolescent↗
PubMed1999

Impingement simulation of the hip in SCFE using 3D models.

OBJECTIVE: Affecting as it does the geometry of adolescent hips, slipped capital femoral epiphysis (SCFE) and its evaluation represent a major three-dimensional problem. The current methods of clinical assessment-geometric measurements of the femur on plain radiographs or on axial computed tomographic (CT) cross-sections-address only one of the two joint components. MATERIALS AND METHODS: We have developed a system to simulate motion of hip joints with physiologic joint contact. In our system, CT-based computer models of the femur, pelvis, etc., are fitted with oriented bounding boxes (OBBs) and manipulated. Collision detection algorithms control the hip motion, which, in this virtual joint, is based on the surface geometry of the joint partners rather than on a predefined fixed rotation center. RESULTS: An illustrative case is presented to show the advantages of the new biomechanical evaluation method over conventional radiological assessments for SCFE. The proposed system provides remarkably high speed, and the necessary data can be prepared in a reasonable time. CONCLUSION: The range-of-motion assessment provides the surgeon with information about the site and the impact of nonphysiologic contact in the hip joint. The information thus obtained can be valuable for indication and planning of corrective surgery in cases of SCFE.

Adolescent↗
PubMed1999

Spinal deformity after selective dorsal rhizotomy in patients with cerebral palsy.

Selective dorsal rhizotomy is used widely as a means of treating spasticity associated with cerebral palsy. Little is known regarding the effect of the procedure on the development or progression of spinal deformity. The authors reviewed six patients with progressive deformity after rhizotomy. Prerhizotomy and postrhizotomy records of physical examinations and radiographs were reviewed retrospectively in an attempt to identify risk factors for development of and/or rapid progression of, spinal deformity. Detailed preoperative and postoperative evaluation of spinal alignment should be undertaken, particularly in those patients who may be at risk of rapidly progressive deformity.

Adolescent↗
PubMed1999

Periacetabular osteotomy without abductor dissection using direct anterior exposure.

The direct anterior exposure is a new abductor sparing surgical approach to perform periacetabular osteotomy, developed in an effort to eliminate the postoperative abductor morbidity associated with the classic Smith-Petersen approach. The direct anterior exposure also allows anterior arthrotomy of the hip joint, necessary to deal with intraarticular disease of the acetabular rim that is common in adult patients who require periacetabular osteotomy. The direct anterior exposure combines the medial portion of the classic Smith-Petersen iliofemoral exposure with or without the second window of the ilioinguinal exposure. An osteotomy of the anterior superior spine is done routinely to facilitate the approach by relaxing the attached sartorius and inguinal ligament origins. The authors' experience with the direct anterior exposure involves 195 consecutive periacetabular osteotomies done since 1992, with 60 operations done using the full approach through two windows and 135 operations done using the limited approach through one window. There was no difference in functional or radiographic results, with both approaches allowing rapid functional recovery, excellent radiographic corrections, rapid bony healing, and minimal formation of heterotopic bone. No osteonecrosis or vascular injuries were seen. In nearly all patients, abductor function had returned to preoperative levels by 3 months after surgery, in distinct contrast to the authors' previous experience with the Smith-Petersen approach. The authors consider the direct anterior exposure to be the surgical approach of choice for periacetabular osteotomy, with the more limited version proving satisfactory in all patients except the largest and most muscular patients. The full version is useful in large male patients.

Acetabulum↗
PubMed1999

Planning acetabular redirection osteotomies based on joint contact pressures.

Acetabular redirection osteotomy can be used to relieve pain, improve function, and extend the life of dysplastic hip joints. To understand better the factors that may determine the acetabular reorientation that minimizes pressures, joint contact pressures were calculated by computer assisted methods in 70 dysplastic and 12 normal hips (82 patients). Calculated pressures were consistent with pressures estimated and measured by other investigators. Contact areas were 26% smaller, and contact pressures were 23% higher, in the dysplastic hips compared with the normal hips. When the acetabula were reoriented to minimize contact pressures for an activity such as the midstance phase of gait, then contact pressures were elevated for dissimilar activities such as stair ascent. Contact pressures in the dysplastic hips were reduced when the acetabula were rotated in the frontal plane to increase lateral coverage or rotated in the sagittal plane to increase anterior coverage. In most of the dysplastic hips, contact pressures were reduced twice as much when the acetabulum was rotated in the frontal and the sagitta' planes. Computer assisted methods to quantify joint contact pressures can be used to assess potential candidates for reconstruction, plan acetabular redirection surgery, and possibly may improve the long term success of acetabular redirection osteotomy.

Acetabulum↗
PubMed1999

Surgical correction of acetabular dysplasia in the adult. A Boston experience.

Acetabular redirection surgery is the mainstay of treatment for the symptomatic, dysplastic hip. The authors' experience with the Salter innominate osteotomy, Wagner spherical acetabular osteotomy and the modified Bernese periacetabular osteotomy shows that major acetabular redirection surgery can reliably improve the structure of the dysplastic hip and delay or prevent secondary osteoarthrosis. The limited correction achieved by the Salter innominate osteotomy suggests this procedure generally should be reserved for younger patients with mild dysplasia. The modified Bernese periacetabular osteotomy is the authors' current preferred method of treating acetabular dysplasia, even in the presence of mild to moderate secondary osteoarthrosis.

Acetabulum↗
PubMed1998

Gadolinium-enhanced MR imaging of pediatric patients after reduction of dysplastic hips: assessment of femoral head position, factors impeding reduction, and femoral head ischemia.

OBJECTIVE: We describe gadolinium-enhanced MR imaging of position and vascular enhancement of the femoral head in pediatric patients who have undergone reduction of hip dislocation. SUBJECTS AND METHODS: Within 24 hr of hip reduction and spica casting, we performed 25 gadolinium-enhanced MR studies in 18 infants and young children (15 girls, three boys) with 23 dysplastic hips. All but two patients underwent closed reductions. We evaluated intraoperative arthrograms for obstacles to reduction and subsequent radiographs for avascular necrosis. RESULTS: MR images showed that all femoral heads were in their respective acetabula, but several structures interfered with concentric reduction. Obstacles to reduction included a pulvinar (n = 16), infolding of the capsule (n = 9), interposition of the labrum (n = 2), and a hypertrophied ligamentum teres and transverse ligament (n = 2). All 50 femoral heads showed enhancement: 35 normally, 10 homogeneously but less than on the contralateral femoral head or the ipsilateral greater trochanter, and five with areas of focally decreased enhancement. Hips that showed decreased enhancement had undergone greater degrees of abduction (r = .38, p < .01). CONCLUSION: Gadolinium-enhanced MR imaging can reveal abnormalities of hip position and proximal femoral epiphyseal and physeal vascularity that can occur after hip reduction. Abnormalities of enhancement were more frequent in patients who had greater femoral abduction. The effect of decreased epiphyseal vascular enhancement is still uncertain.

Arthrography↗
PubMed1998

[The Boston concept. peri-acetabular osteotomy with simultaneous arthrotomy via direct anterior approach].

To this point, we have only a relatively short term followup in 32 patients with known labral lesions who have been treated by combined periacetabular osteotomy (PAO) and debridement of the damaged anterior labrum. A positive clinical history in association with pain demonstrated with the impingement test of flexion-adduction-internal rotation nearly always indicates macroscopic pathology within the anterior portion of the hip joint. Labral lesions associated with acetabular dysplasia seem more common with increasing age. Labral lesions seem to correlate with arthrosis. We suspect that uncorrected impinging lesions of the anterior rim have led to some of our early clinical failures after PAO. We feel that intra-articular treatment of certain impinging lesions may improve the clinical outcome in these patients. Correction of the pathological mechanics in the mature, dysplastic hip certainly requires restoration of stability by reorienting osteotomy. If intra-articular derangements of the anterior rim are also present, though, intra-articular surgery may also be necessary to optimize the outcome. Our early results suggest that the earlier and more complete the correction of the disordered mechanics in the dysplastic hip, the more complete and long-lasting will be both relief of clinical symptoms and preservation of a joint free from arthrosis. Anterior arthrotomy to explore the anterior rim, carried out at the time of PAO, employing the direct anterior abductor-sparing approach (DAA), seems a safe and useful adjunct in treating the mature, dysplastic hip. Much longer clinical followup and larger treatment groups will be necessary to allow firm conclusions concerning optimal treatment programs for different patient subgroups of the adult hip dysplasia syndrome.

Acetabulum↗
PubMed1997

Complications when using the cannulated 3.5 mm screw system.

Five patients with breakage of instrumentation when using the cannulated 3.5 mm screw system for fracture fixation are reported. Four 1.25 mm guide wires were sheared off by the cannulated drill and one 3.5 mm cannulated tap sleeve fractured. This article presents potential dangers when using the cannulated 3.5 mm screw system for general fracture care.

Adolescent↗
PubMed1996

Oblique proximal tibial osteotomy for the correction of tibia vara in the young.

Proximal tibial osteotomy in the growing patient historically has been associated with a high rate of neurovascular complications and malunion. Here is reported a technique of valgus proximal tibial osteotomy, of the incomplete closing wedge type, that has avoided neurovascular compromise while achieving reliable correction and rapid bony union. Oblique proximal tibial valgus osteotomies with lateral tension plate fixation were performed on 18 tibiae in 14 patients (age range, 5-25 years) with tibia vara. The primary diagnosis was Blount's disease in 13 tibiae, achondroplasia in 2 tibiae, multiple epiphyseal dysplasia in 2 tibiae, and hypochondroplasia in 1 tibia. No postoperative plaster immobilization was necessary. All patients were able to bear weight fully by 8 weeks after surgery. Average angular correction was 18 degrees. One patient had overcorrection because of an unrecognized intraoperative fracture of the media] tibial cortex. There were no neurovascular complications. No growth disturbance of the proximal tibial physis was noted. Oblique proximal tibial osteotomy with tension plate fixation successfully corrected varus deformity of the proximal tibia in the growing patient without damage to the proximal tibial physis or neurovascular compromise.

Adolescent↗
PubMed1994

Spinal deformity associated with neurenteric cysts in children.

STUDY DESIGN: Neurenteric cysts are uncommon lesions originating from the primitive foregut that may involve adjacent vertebrae and spinal cord. Little is known regarding the natural history of these cysts and associated spinal deformity in children. Five patients with these cysts managed at the authors' institution from 1955 to 1993 were reviewed. OBJECTIVES: The goal of this retrospective review was to determine the natural history of these cysts in children, and to assess the surgical management in each of the five patients. METHODS: Medical charts and radiographic records were reviewed and, when possible, the patients were re-evaluated clinically. RESULTS: All patients had significant anterior vertebral defects, and four had severe kyphosis at presentation. Major complications occurred in three of the four patients treated surgically. CONCLUSIONS: Iatrogenic complications of surgical management of these cysts can be limited by combined anterior and posterior approaches, providing the most complete exposure and maximal stabilization of the associated deformity.

Child↗
PubMed1993

The function of the quadriceps muscle after a fracture of the femur in patients who are less than seventeen years old.

Thirty-three patients who had been managed for an isolated, closed fracture of the femoral shaft when they were less than seventeen years old were examined at an average of thirty-three months (range, eighteen to fifty-six months) after the injury. Thirteen patients (39 per cent) had a persistent deficit in the strength of the quadriceps of the fractured limb, as identified on testing with a Cybex-II isokinetic dynamometer. Six patients (18 per cent) had a deficit according to the one-leg-hop for distance test, fourteen (42 per cent) had an average loss of ten millimeters in the circumference of the thigh, and sixteen (48 per cent) had an average loss of 10 degrees of flexion of the knee. The etiological factors that were thought to possibly be responsible for the weakness of the quadriceps were evaluated. The amount of maximum displacement of the fracture, as seen on the initial radiographs, was the only factor that was significant for the prediction of weakness of the quadriceps (p = 0.006) at both test speeds of the Cybex dynamometer and in all statistical analyses. Despite the persistent weakness of the quadriceps, none of the patients had a clinical problem at the latest follow-up examination. A subclinical deficit in the strength of the quadriceps may be related to damage sustained by the muscle at the time of the fracture. On the basis of the results of this study, we do not recommend a change from the traditional methods of treatment, which involve early application of a spica cast or use of traction followed by application of a spica cast.

Adolescent↗
PubMed1993

The dinner fork technique for treating displaced lateral condylar fractures of the humerus in children.

A simple, inexpensive fracture-reduction instrument and guide for Kirschner wire insertion can be constructed using a "dinner fork" and pliers. The modified dinner fork is particularly useful as an aid for reducing, compressing, and fixing displaced lateral condylar fractures of the distal humerus in children. This device is effective and simple to use; it can be applied to other pediatric fractures as well.

Bone Wires↗
PubMed1992

Osteotomies of the hip in the prevention and treatment of osteoarthritis.

Osteoarthritis of the hip is common in our society, even in the relatively young patient. Most of this osteoarthritis is mechanical in etiology and is secondary to residual deformity from developmental hip disease. This type of osteoarthritis can often be predicted and prevented if the causative excessive joint pressures are reduced in a timely fashion by corrective osteotomy. Realigning pelvic or intertrochanteric osteotomy of this preventive type is termed reconstructive; those osteotomies performed after osteoarthritis is established are termed salvage. Corrective osteotomy will be clinically successful only if the mechanical etiology for the potential or established osteoarthritis is clear and if the osteotomy succeeds in reducing the pathologically excessive joint loads. The clinical success of osteotomy also requires precise technical planning preoperatively and careful operative technique.

Adolescent↗