Freeman Miller

Relationships among musculoskeletal impairments and functional health status in ambulatory cerebral palsy.

Orthopedic surgery for patients with cerebral palsy addresses motion impairments, assuming that this will improve motor function. This study evaluates the relationships among clinical impairment measures with standardized assessments of function and disability as an initial step in testing this assumption. A total of 129 ambulatory children and adolescents across six institutions participated in a prospective evaluation that consisted of passive motion and spasticity examination of the lower extremities, three-dimensional gait temporal-spatial and kinematic analysis, and administration of the Gross Motor Function Measure (GMFM) and the Pediatric Outcomes Data Collection Instrument (PODCI). The analysis found that isolated impairment measures of motion and spasticity were only weakly related to motor function in cerebral palsy and even when averaged across multiple joints yielded no more than a fair correlation with functional scores, nor did a combination of impairments emerge that could predict substantial variance in motor function. These findings suggest that caution should be exercised when anticipating functional change through the treatment of isolated impairment and that addressing multiple impairments may be needed to produce appreciable effects.

Lateral femoral scan: an alternative method for assessing bone mineral density in children with cerebral palsy

Background. Children with cerebral palsy (CP), often nonambulatory and/or on anticonvulsants, are at increased risk for fractures. Bone mineral density (BMD) measured by the conventional techniques of dual-energy X-ray absorptiometry (DXA) often cannot be reliably or easily measured in these patients. Objective. To find an alternative site to whole body, spine and hip that can be conveniently used to measure BMD in CP patients. Materials and methods. Having observed that CP patients prefer to lie on their sides, we explored measuring BMD at the distal femur in the lateral projection. A total of 92 scans were performed without sedation in 34 children and adolescents with CP, aged 4–19 years. Four femoral shaft subregions were created: two trabecular and two cortical. Results. The coefficients of variation (CV %) were generally higher for opposite-side comparisons (n = 12 patients) than for same-side comparisons (n = 16 patients). For intra- and interobserver analyses, CV % were higher for cortical regions than for trabecular regions. Overall, the CV % were similar to those for hip and spine. Conclusion. This peripheral site in the femur should be considered as an alternative for patients with CP when whole-body, hip and spine DXA are not practical.

Soft-tissue release for spastic hip subluxation in cerebral palsy.

Children with spastic hip subluxation secondary to cerebral palsy were treated with a standard protocol that focused on early detection of the subluxation using physical examination and anteroposterior pelvis radiographs. Using limited hip abduction of < or =30 degrees and subluxation of > or =25% migration percentage as indications, patients had open adductor and iliopsoas lengthenings with immediate postoperative mobilization and no abduction bracing. The protocol was applied to 74 children with a mean age of 4.5 years and had 147 hips surgically addressed. Of these hips initially, 20% were normal (migration percentage <25%), 52% were mildly subluxated (migration percentage 25-39%), 22% were moderately subluxated (migration percentage 40-59%), and 6% were severely subluxated (migration percentage > or =60%). At a final postoperative follow-up of 39 months, 54% of these hips were classified as good (migration percentage <25%), 34% were fair (migration percentage 25-39%), and 12% were poor (migration percentage > or =40%). Of this patient population, 69% were nonambulators and their outcomes were not statistically different from children who could walk. No child developed an abduction contracture or wide-based gait that required treatment. With early detection and applying this treatment algorithm, 80% of children with spastic hip disease should have good or fair outcomes. Longer follow-up will be required to determine how many children will need bony reconstruction to maintain stable and located hips at the conclusion of growth.

The dynamic balance of the children with cerebral palsy and typical developing during gait. Part I: Spatial relationship between COM and COP trajectories

Analysis of the COM or COP movement has been a simplified method to illustrate the balance disorders in static stance and gait, but has its limitation when examined alone. Dynamic stability of 32 children with cerebral palsy (CP) was examined and compared with 10 typically developing (TD) children by measuring the displacement of center of mass (COM) and center of pressure (COP) and their spatial relationship. The children with CP were further divided into two groups based on topographical involvement, hemiplegia (Hemi) and diplegia (Di). The participants walked with their preferred speed at least 5 successful trials on a walkway with two force plates mounted in the middle. An eight-camera motion analysis was used to capture 26 reflective markers secured at the bony landmarks of the participant. The data obtained from motion analysis and force plates was used to calculate COM and COP. The results showed either of two CP groups demonstrated significantly greater peak-to-peak COM and COP displacement in medio-lateral (ML) and lower peak-to-peak COM and COP displacement in anterio-posterior (AP) direction than TD group. The root mean square (RMS) of COM-COP divergence of Hemi and Di groups were higher than that of TD group in AP and ML direction, but only the difference in ML direction was significant. Present study demonstrates that COM-COP divergence can characterize the dynamic balance of the CP children in walking, and thus assist in comparing and differentiating balance patterns.

Adipose Tissue Infiltration of Skeletal Muscle in Children with Cerebral Palsy

OBJECTIVE To determine whether children with quadriplegic cerebral palsy (QCP) have a greater adipose tissue (AT) infiltration of skeletal muscle than typically developing children (12/group and 5-14 years). STUDY DESIGN Cross-sectional area (CSA) of AT and muscle in the midthigh were assessed with magnetic resonance imaging. Physical activity was assessed with an activity monitor. RESULTS Children with QCP had 2.3-fold higher intermuscular AT CSA and 51% lower muscle CSA in the midthigh than control subjects. Midthigh intermuscular, subfascial, and subcutaneous AT CSA adjusted for midthigh muscle CSA were higher in children with QCP (all P < .05). Moreover, the proportion of intermuscular AT CSA and subfascial AT CSA relative to subcutaneous AT CSA in the midthigh were 2.5-fold and 1.8-fold higher in children with QCP than control subjects (all P < .05). Children with QCP also had 70% fewer physical activity counts, which was inversely related to intermuscular AT CSA (r = -0.76) and subfascial AT CSA (r = -0.63) adjusted for muscle CSA in the midthigh of children with QCP (both P < 0.05), but not in control subjects. CONCLUSION Children with QCP have a greater AT infiltration of skeletal muscle than typically developing children, which is related to their low level of physical activity.

A Study of Desmopressin and Blood Loss during Spinal Fusion for Neuromuscular Scoliosis A Randomized, Controlled, Double-Blinded Study

Background: Studies examining the use of desmopressin acetate (DDAVP) have shown variable results in DDAVPs efficacy for reducing blood loss. Studies of adults having cardiac surgery and of children having spinal fusion have suggested that patients with complicated medical histories and complex surgical procedures may benefit from use of DDAVP. Therefore, this study was designed to examine the homeostatic effects of DDAVP in children with severe cerebral palsy undergoing spinal fusion. Methods: A randomized, double‐blinded, and placebo‐controlled trial of DDAVP was designed to enroll 40 patients. However, termination of the study was advised by the Institutional Review Board after 21 patients were enrolled. All patients had spastic quadriplegic‐type cerebral palsy and were randomly assigned to one of two groups. The DDAVP group received 0.3 micro gram/kg DDAVP in 100 ml normal saline, and the placebo group received normal saline alone. All patients were anesthetized with nitrous oxide, oxygen, isoflurane, and fentanyl. Factor VIIIC and von Willebrands factor (vWF) concentrations were measured in blood drawn before DDAVP infusion and 1 h after infusion. Blood pressure was maintained at a systolic pressure of less than 100 mmHg. Use of crystalloids, packed erythrocytes, platelets, and fresh frozen plasma were based on criteria established by protocol. Estimated blood loss was assessed by weighing sponges and measuring suctioned blood from canisters. Results: Estimated blood loss (intraoperative and postoperative) and amount of packed erythrocytes transfused were similar for the DDAVP and placebo groups. Concentrations of both factor VIIIC and vWF were significantly greater after DDAVP infusion when compared with concentrations after placebo infusion. Conclusions: In the children who had complex spinal fusion, there was no difference in estimated blood loss between those who received DDAVP and those who received a placebo. Administration of DDAVP significantly increased factor VIIIC and vWF levels.

The dynamic balance of the children with cerebral palsy and typical developing during gait Part II: Instantaneous velocity and acceleration of COM and COP and their relationship

As a companion research subsequent to analyzing displacement of center of mass (COM) and center of pressure (COP) in Part I, the purposes of this study were to quantify dynamic stability using magnitudes and patterns of instantaneous velocity and acceleration of COM and COP of the children with cerebral palsy (CP) during walking, and compare the data with those of the typically developing (TD) children. The instantaneous velocity and acceleration of COM and COP were acquired by calculating the first and second derivatives of displacement data presented in Part I. Velocity and acceleration of COM and COP were normalized by each participants leg length to eliminate the influence of individuals stature. The results indicate that the preferred walking speed is significantly higher in TD groups than hemiplegic group (Hemi) and diplegic group (Di). The peak values of instantaneous velocity and acceleration of COM in vertical, medio-lateral (ML) and antero-posterior (AP) directions and velocity and acceleration of COP in ML direction were significantly higher in Di group than TD group. Both CP groups showed great variability in COM and COP parameters. Therefore, although Di group demonstrated higher peak values than Hemi group, the only significant difference between two groups was instantaneous COP velocity in ML direction. The findings of this study suggest that this assessment may be of value for research or clinical evaluation of dynamic balance dysfunction during walking and provide comparisons and insights for specific treatments or surgical interventions for the children with CP.

Life expectancy in pediatric patients with cerebral palsy and neuromuscular scoliosis who underwent spinal fusion.

The aim of this study was to document the rate of survival among 288 severely affected pediatric patients (154 females, 134 males) with spasticity and neuromuscular scoliosis who underwent spinal fusion (mean age at surgery 13 years 11 months, SD 3 years 4 months), and to identify exposure variables that could significantly predict survival times. Kaplan-Meier survival analysis was performed demonstrating a mean predicted survival of 11 years 2 months after spinal surgery for this group of globally involved children with cerebral palsy (CP). Coxs proportional hazards model was used to evaluate predictive efficacy of exposure variables, such as sex, age at surgery, level of ambulation, cognitive ability, degree of coronal and sagittal plane spinal deformity, intraoperative blood loss, surgical time, days in hospital, and days in the intensive care unit. Number of days in intensive care unit after surgery and the presence of severe preoperative thoracic hyperkyphosis were the only factors affecting survival rates. This demonstrated statistically significant predictability for decreased life expectancy after spinal fusion in children with CP.

Are antifibrinolytics helpful in decreasing blood loss and transfusions during spinal fusion surgery in children with cerebral palsy scoliosis

Study Design. Therapeutic comparative study. Objective. To evaluate the safety and efficacy of antifibrinolytic (AF) agents in reducing blood loss and transfusions during posterior spinal fusion (PSF) in children with cerebral palsy (CP) scoliosis. Summary of Background Data. Scoliosis surgery in CP children is associated with substantial blood loss. Few reports on the role of AFs exist. Methods. A multicenter, retrospective review of a prospectively collected database of 84 consecutively enrolled patients with CF (age < 18 years) with spinal deformity who underwent PSF and instrumentation. The use of AFs, tranexamic acid (TXA), epsilon-aminocaproic acid (EACA), or none was based on the surgeon preference. Estimated blood loss (EBL), transfusion requirements, and length of stay were recorded. Analysis was performed with the independent-samples t test and 1-way analysis of variance with post hoc Bonferroni analysis. Results. The average age at the time of surgery was 14.4 ± 2.6 years. The groups were well matched in preoperative major deformity, age, levels fused, and operating time. Forty-four patients received AFs (30 TXA and 14 EACA), and 40 received no antifibrinolytics (NAF). The EBL averaged 1684 mL for the AFs group and 2685 mL for the NAF group (P = 0.002). There was more cell salvage transfusion in the NAF group. No significant differences were found in total transfusion requirements. There was a trend for decreased hospital stay in the AFs group. No adverse effects were seen. On comparison of the 3 groups (NAF, TXA, and EACA), a significant difference was observed between the TXA and the other groups with respect to EBL and cell salvage transfusion. Conclusion. AFs significantly reduced intraoperative EBL associated with PSF, with no adverse effects; however, we could not demonstrate significant differences in total transfusion, except in cell salvage. TXA was more effective than EACA in decreasing the EBL and cell salvage transfusion.

Distal hamstring lengthening in ambulatory children with cerebral palsy: primary versus revision procedures.

To document the benefits and limitations of distal hamstring lengthening (HL), 61 children (105 limbs) with cerebral palsy treated by distal HL with complete preoperative and postoperative evaluations were reviewed. There was significant improvement in popliteal angle, fixed knee flexion contracture, knee angle at foot contact (FC), and mid-stance knee extension after HL. On the other hand, the hip power generation peak decreased, and the anterior pelvic tilt increased. For the repeated HL (22 limbs), the fixed knee flexion contracture and knee flexion at FC improved. In a group of ten patients (17 limbs) with further postoperative follow up evaluations, the only significant clinical finding related to hamstring function between the first postoperative and the follow up evaluations with no intervening surgery was an increase in the popliteal angle of 20 degrees. Because the popliteal angle may increase over time after HL with no other directly related gait changes, the indications for repeated HL should include fixed knee flexion contracture and increased knee flexion at FC. The increase in the popliteal angle alone should not be considered an indication for repeated HL.