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Biomedical subjects

Takahide Kurokawa

Publications and source records attributed to Takahide Kurokawa.

6 recordsLinked to original sources

Fusionless surgery for scoliosis: 2-17 year radiographic and clinical follow-up.

STUDY DESIGN: Descriptive case series. OBJECTIVE: To determine whether fusionless, multiple vertebral wedge osteotomy can safely obtain correction of the deformity with adolescent idiopathic scoliosis (AIS). SUMMARY OF BACKGROUND DATA: To our knowledge, no such attempts to manage the AIS with fusionless, vertebral osteotomies have been reported. METHODS: A total of 20 consecutive patients were treated since 1987. Deformity correction, complications, respiratory function, and patient-oriented outcome were investigated. RESULTS: There were 20 patients (17 females and 3 males), including 19 with idiopathic and 1 with syringomyelia scoliosis, who underwent surgery at an average age of 16.4 years and were followed for 8.9 years (range 2-17) on average. There were no neurologic complications. One superficial wound infection necessitated debridement. There were 2 patients converted to posterior instrumentation surgery because of deterioration of the deformity. The average Cobb angle of 64.0 degrees before surgery was corrected to 48.2 degrees at 8.9 years after surgery. Decline of the pulmonary function test after surgery was not statistically significant. The patients' responses to questions about function and pain were favorable. CONCLUSION: Deformity with AIS was safely corrected with fusionless, multiple vertebral wedge osteotomy.

Adolescent↗

Skin behavior during leg lengthening in patients with achondroplasia and hypochondroplasia: a short-term observation during leg lengthening.

BACKGROUND: Although distraction osteogenesis is a recently established method of limb lengthening, it is not well known how soft tissues behave during bone lengthening. Because skin is tissue that can be easily and directly observed, we analyzed skin extension during limb lengthening to study the condition of soft tissues. METHOD: We examined three achondroplastic and two hypochondroplastic patients who underwent bilateral tibial lengthening with unilateral bone lengtheners. To analyze skin extension during leg lengthening, the bilateral skin surface was marked in a latticework pattern, starting 10 cm proximal to the knee joint down to 10 cm distal to the ankle joint, with black ink. The longitudinal length and the area of lattices, and the circumferential length of legs were measured. RESULTS: We found that: (1) the longitudinal extension of the skin during leg lengthening occurs not only in the bone lengthening portion between fixator pins but also around the knee or ankle joints; (2) circumferential length of legs was decreased, and soft tissue volume also does not increase in proportion to the increase in leg length. Soft tissue volume started to increase in the central region of the legs after a 30% increase in leg length was obtained, resulting in the 10% increase in the volume at the end point. CONCLUSIONS: These data suggest that soft tissue extension precedes soft tissue neogenesis at least during the initial period of leg lengthening, possibly based on its viscoelastic properties. After a 30% increase in leg length is obtained, soft tissue neogenesis takes place in the central region of the leg.

Achondroplasia↗

Multiple vertebral wedge osteotomy for adolescent idiopathic scoliosis.

19 idiopathic and 1 syringomyelia scoliosis patients (17 females and 3 males) underwent fusionless, multiple vertebral wedge osteotomy and with follow-up for an average of 8.9 years. The average age at surgery was 16.4 years. The average curve magnitude measured by Cobb was 64.0 degrees before surgery, 38.8 degrees after surgery, 43.7 degrees one year after surgery, 46.9 degrees two years after surgery and 48.2 degrees at the latest follow-up. The difference between the Cobb angle two years after surgery and latest follow-up was not significant. There were no major complications such as neurological problems.

Adolescent↗

Measurement of the tensile forces during bone lengthening.

BACKGROUND: The purpose of this study was to investigate the effects of lengthening frequency on mechanical environment in limb lengthening. METHODS: Tensile forces were continuously monitored using a load sensor attached to a unilateral external fixator. Twenty patients were monitored. Ten patients were with acquired femoral shortening, and five of them underwent quasi-continuous lengthening of 1440 steps per day, and the other five received step lengthening twice a day. The other 10 patients were with achondropalsia. Five of them underwent the same quasi-continuous lengthening, and the other five received the same step lengthening. The circadian change and the daily course of the tensile forces were assessed and compared between quasi-continuous lengthening and step lengthening. FINDINGS: As for circadian change, an acute increase in the force took place simultaneously with each step of lengthening in the step-lengthening group, but very little change of the baseline force level was seen during quasi-continuous lengthening. As for daily course of the tensile force, it increased almost linearly in both lengthening frequency groups in the initial stage of lengthening. No significant difference of the average force increment rate in this phase was recognized between the quasi-continuous and step lengthening groups irrespective of the etiologies. INTERPRETATION: The lengthening frequency greatly affected the circadian change of the tensile force, but did not affect the increment rate of the force in the linear phase.

Adolescent↗

A femoral neck fracture model in rabbits.

A technique was developed to create a reproducible femoral neck fracture in vitro using 5-month-old JW/CSK series male rabbits. Force attenuation of a newly developed damping material was also evaluated using this model. Ten pairs of the femora with smaller deviations in length and weight were harvested and cleaned of soft tissue. Either a right or left of each pair of the specimens was randomly selected and put into either the control or the experimental group, both of which contained equal numbers of the right and left femora. The specimens were attached to an L-shaped plate and embedded in a resin from the proximal diaphysis to the distal end so as to maintain a consistent position of the femora. They were mounted and fixed on a pedestal slanted in the coronal plane at 20 degrees. The impact load testing was conducted using an impact mallet dropped from a height of 3 cm. The impact load was applied onto the femoral head. To the specimens in the experimental group, attenuated impact forces were loaded through the damping material, but those in the control group were subjected to forces directly transmitted without the material. All the impact testing was performed in a temperature and humidity controlled chamber. All of the femoral specimens exposed to the direct impact forces (controlled group) sustained fracture at the neck. The fracture line passed from the base of the femoral head laterally and to the calcar area just proximal to the minor trochanter medially. The location of each fracture line was almost identical among the specimens. None of the specimens that were exposed to the impact force through the damping material (experimental group) sustained fracture macroscopically and roentgenographically.

Animals↗