Janet L. Walker

Gait-stance duration as a measure of injury and recovery in the rat sciatic nerve model

The rat sciatic nerve is a well-established animal model for the study of peripheral nerve crush injury. Footprint analysis is the most widely used non-invasive method of measuring functional recovery after injury in this model. However, this method has significant limitations due to inability to obtain clear reproducible prints, especially when the injury is severe, and variation of these prints with gait velocity. In the case of contracture or toe loss, footprint analysis is unreliable. We describe a new technique, gait-stance duration, which is capable of non-invasively quantitating functional recovery in the rat model. This method is not dependent on accurate foot positioning during gait. It utilizes video recording of the animal walking and measures the time each hind foot is in contact with the floor by counting the number of frames that pass. By pairing consecutive steps, it minimizes variation due to changes in velocity and, by calculating a ratio of injured/uninjured hind feet, comparisons to normal gait can be made. This method shows recovery patterns similar to footprint analysis with small inter-animal variability. We believe it has significant advantages over footprint analysis for the measurement of functional recovery in the crushed sciatic nerve rat model.

Clinically prescribed orthoses demonstrate an increase in velocity of gait in children with cerebral palsy:a retrospective study

The purpose of this study was to determine the effect clinically prescribed ankle-foot orthoses (AFOs) have on the temporal-spatial parameters of gait, as compared with barefoot walking in children with cerebral palsy. A retrospective chart review of data collected between 1995 and 1999 in our motion analysis laboratory was performed. A retrospective chart review of 700 patients revealed 115 patients (mean age 9 years) who had a primary diagnosis of CP (diplegia n=97, hemiplegia n=18). All were wearing clinically prescribed hinged or solid AFOs at the time of undergoing a three dimensional gait analysis. In line with our standard clinical practice, data for both conditions (braced and barefoot walking) were collected the same day by the same examiner. Statistical analyses indicated the temporal and spatial gait parameters of velocity, stride length, step length, and single limb stance were significantly increased (p<0.001) with the use of AFOs versus barefoot walking. Cadence was the only parameter found to not be statistically different.

Enhancement of Functional Recovery Following a Crush Lesion to the Rat Sciatic Nerve by Exposure to Pulsed Electromagnetic Fields

Previous studies showed that exposure to pulsed electromagnetic fields (PEMF) produced a 22% increase in the axonal regeneration rate during the first 6 days after crush injury in the rat sciatic nerve. We used the same injury model to assess the effect on functional recovery. The animals were treated with whole body exposure to PEMF (0.3 mT, repetition rate 2 Hz) for 4 h/day during Days 1-5 while held in plastic restrainers. Functional recovery was serially assessed up to Postinjury Day 43 using recently described video imaging of the 1-5 toe spread and the gait-stance duration. Footprint analysis was also used with calculation of a sciatic function index. Those animals treated with PEMF had improved functional recovery, as compared to sham controls, using the tests for video 1-5 toe spread and gait-stance duration (P = 0.001 and P = 0.081, respectively). This effect was found throughout the 43-day recovery period. No effect was found using the sciatic function index. This study confirms that functional recovery after nerve crush lesion is accelerated by PEMF and has broad implications for the clinical use of these fields in the management of nerve injuries.

A Comparison of Three Methods of Pain Control for Posterior Spinal Fusions in Adolescent Idiopathic Scoliosis

Study Design. Retrospective cohort study. Objective. To compare the efficacy of patient-controlled analgesia (PCA) with morphine alone, a single preoperative intrathecal morphine injection and PCA (IT/PCA), and epidural catheter infusion without PCA (EPI) for postoperative pain control after posterior spinal fusion (PSF) and segmental spinal instrumentation (SSI) in adolescent idiopathic scoliosis (AIS). Summary of Background Data. Postoperative pain control after PSF and SSI in AIS can be managed in different ways. EPI provides for a longer period of pain relief but is reliant on the correct placement and maintenance of the catheter in the epidural space. A single preoperative intrathecal morphine injection also provides for long acting analgesia. No direct comparison of these 3 methods of postoperative pain control has been reported. Methods. An IRB-approved retrospective chart review was performed at 2 institutions from 1997 to 2005. The medical record was reviewed to determine pain scores after surgery at multiple time periods. The 3 groups were compared using Student t test and &khgr;2 and significance was defined as P < 0.05. Results. There was no statistical difference in the gender, age, magnitude of curve, or number of levels fused in the IT/PCA (N = 42), PCA (N = 41), or EPI (N = 55) groups. Postoperative pain scores were lowest in the IT/PCA group in the first 8 hours (P < 0.05) but the pain scores in the EPI group were then lower through 24 hours (P < 0.05). Total morphine use (mg/kg) was lower in the IT/PCA group compared with the PCA group at 12 hours and 24 hours (P = 0.0001). Return to solid food ingestion was quickest in the EPI group (2.0 days) followed by the IT/PCA (2.6 days) and PCA alone (3.2 days) (P < 0.002). Respiratory depression and transient neurologic change occurred most frequently in the EPI group (EPI 11/55 pts vs. 1/42 IT/PCA vs. 0/41 PCA P < 0.001). Pruritis was greatest in the epidural group (11/55 P < 0.05). There were no intraoperative somatosensory-evoked potential changes or permanent neurologic injury recorded in any group. Conclusion. An EPI controls postoperative pain for the longest period of time and allows for a quicker return to consumption of solid foods. However, a single preoperative intrathecal morphine injection controls the pain equally for the first 24 hours with less pruritis and with less adverse events thus requiring less nursing and physician intervention after PSF and SSI in AIS. All methods were safe with no neurologic injury recorded.

Improved footprint analysis using video recording to assess functional recovery following injury to the rat sciatic nerve

Footprint analysis is a non-invasive method to quantitate functional recovery after crush injury in the rat sciatic nerve model. Traditional methods of producing the footprints for measurement are limited by inability to reliably produce clear prints when the injury is severe. We describe the use of video technique with image analysis to record and measure these prints. Video had fewer unmeasurable prints than ink. For the 1-5 and 2-4 toe spreads, there was good correlation of video measurements with ink method and better repeatability using video as compared with ink. However, the print length parameter determined by video had poorer repeatability and poorly correlated with that measured by ink. Therefore, calculation of a Sciatic Function Index by video is not appropriate. Since the print length also varies with gait velocity, we believe that a ratio of injured:uninjured hindfoot 1-5 toe spreads as measured by video is a more reliable and repeatable measure of functional recovery in this model.

Hip abnormalities in children with Charcot-Marie-Tooth disease.

Hip dysplasia was recently observed in association with Charcot-Marie-Tooth disease (CMT). We retrospectively reviewed available radiographs of 74 of 100 children with clinically and electrodiagnostically proven CMT and noted six cases of hip dysplasia. Minor hip abnormalities, most commonly increased neck shaft angles, were noted in 21 other patients. Type I usually causes more weakness and had more hip dysplasia than type II. A female predominance was noted but may have resulted from sampling of more immature radiographs in males. Most dysplasia was asymptomatic and was detected only on screening radiographs.

Adult Outcomes Following Amputation or Lengthening for Fibular Deficiency

BACKGROUND Fibular deficiency results in a small, unstable foot and ankle as well as a limb-length discrepancy. The purpose of this study was to assess outcomes in adults who, as children, had had amputation or limb-lengthening, commonly used treatments for fibular deficiency. METHODS Retrospective review of existing data collected since 1950 at six pediatric orthopaedic centers identified 248 patients with fibular deficiency who were twenty-one years of age or older at the time of the review. Excluding patients with other anomalies and other treatments (with the excluded group including six who had had lengthening and then amputation), we identified ninety-eight patients who had had amputation or limb-lengthening for the treatment of isolated unilateral fibular deficiency. Sixty-two patients (with thirty-six amputations and twenty-six lengthening procedures) completed several questionnaires, including one asking general demographic questions, the Beck Depression Inventory-II, the Quality of Life Questionnaire, and the American Academy of Orthopaedic Surgeons Lower Limb Questionnaire including the Short Form-36. A group of twenty-eight control subjects completed the Beck Depression Inventory-II and the Quality of Life Questionnaire. RESULTS There were forty men and twenty-two women. The average age at the time of the interview was thirty-three years. There were more amputations in those with fewer rays and less fibular preservation. Lengthening resulted in more surgical procedures (6.3 compared with 2.4 in patients treated with amputation) and more days in the hospital (184 compared with sixty-three) (both p<0.0001). However, when we compared treatment outcomes we did not find differences between groups with regard to education, employment, income, public assistance or disability payments, pain or use of pain medicine, sports participation, activity restriction, comfort wearing shorts, dislike of limb appearance, or satisfaction with treatment. No patient who had been treated for fibular deficiency reported signs of depression. The only significant difference between treatment groups shown by the Quality of Life Questionnaire was in the scores on the Job Satisfiers content scale, with the amputees scoring better than the patients treated with lengthening (p=0.015). The American Academy of Orthopaedic Surgeons Lower Limb Module did not demonstrate differences in health-related quality of life or physical function. CONCLUSIONS The patients who were treated with lengthening had started out with more residual foot rays and more fibular preservation than the amputees. They also required more surgical intervention than did those with an amputation. While patients with an amputation spent less of their childhood undergoing treatment, they were found to have a better outcome in terms of only one of seventeen quality-of-life parameters. Both groups of patients who had had treatment of fibular deficiency were functioning at high levels, with an average to above-average quality of life compared with that of the normal adult population.

Ultrasonography of the unossified patella in young children.

Ultrasonography has become a useful technique to assess the cartilaginous hip of the newborn. We applied this technique and found that it gave useful information in helping to locate the unossified patella in two cases of congenital dislocation of the patella.

Spinal deformity in Charcot-Marie-tooth disease

Study Design This retrospective study revlewed 100 children with clinically and electrodiagnostically proven Charcot-Marie-Tooth disease (CMTD) Objective To determine the incidence of spinal deformity in children with CMTD. Summary of Background of Data A 10% incidence of hyphoscoliois has been reported. Methods All charts and electrodiagnostic studies were reviewed to confirm that CMTD diagnostic criteria were met. Existing radiographs on 89 children were available. Cobb angles were measured and deformity was defined as scoliosis ≥ 10° and kyphosis >40°. Results Thirty-seven of 89 CMTD children had spinal deformity. There was scoliosis in 20, kyphoscoliosis in 14, and kyphosis in 3. In children with radiographs taken at maturity, 50% had deformity. The most common scolotic pattern was a thoracic curve with convexity in either direction. Spinal deformity is more likely in fermale and Type 1 patients. Conclusion This study found an incidence of 37%-50% spiral deformity in children with CMTD, with female and Type 1 patients at greatest risk. However, the deformity rarely required treatment.

The results of preoperative halo-gravity traction in children with severe spinal deformity.

Halo-gravity traction has been used preoperatively for patients with severe spinal deformity but there are limited data in the literature on the results and complications. We studied the outcomes of perioperative halo-gravity traction in children with severe spinal deformity. A retrospective study was carried out on patients who were treated at our center. Twenty-one patients were included in the study. Radiographic and pulmonary function parameters showed significant improvement during the course of traction and at the final follow-up. The overall complication rate was 19%, including two patients with pin loosening and two patients with superficial pin-site infections treated with oral antibiotics.