ABSTRACT
A bilateral New Zealand white rabbit model of distraction osteogenesis (DO) was used to investigate the relationship between strain environment and bone regeneration during limb lengthening. In seven (n = 7) rabbits, a stiffener was applied to the fixator on one side to reduce strains within the gap tissue after lengthening was completed. Animals were euthanized six days later and their distraction zones were harvested and analyzed for changes in new bone volume and architecture. Nonlinear finite element analyses (FEA) were performed to predict changes in the gap strain environment. FEA results predicted a nearly uniform sevenfold decrease in average strain measures within the distraction zone. No change in total average new bone volume and significant decreases in both bone volume fraction (BV/TV) and trabecular thickness (Tb.Th) were observed in tibiae in which gap strains were reduced experimentally, compared to contralateral controls. These results suggest that fixator stiffening influenced the architecture but not the amount of newly formed bone. This animal model of distraction might be used to study the mechanisms by which strain fields affect events in bone repair and regeneration, such as cell proliferation, precursor tissue differentiation, and altered growth factor and nutrient delivery to tissues.
Subject(s)
Bone Regeneration/physiology , Osteogenesis, Distraction , Animals , Biomechanical Phenomena , Bone and Bones/anatomy & histology , Bone and Bones/pathology , Bone and Bones/physiology , Disease Models, Animal , External Fixators , Image Processing, Computer-Assisted , Male , Models, Anatomic , Rabbits , Tibia/anatomy & histology , Tibia/physiology , Tomography, X-Ray ComputedABSTRACT
Extracorporeal life support is a therapeutic modality that can provide cardiorespiratory support for multiply injured patients. Fourteen patients with multiple trauma who sustained pelvic or long bone fractures were referred for treatment with extracorporeal life support at the University of Michigan Medical Center. All patients were considered morlbund secondary to their pulmonary injury. Six of the 14 patients had bilateral pulmonary contusions. The mean Injury Severity Score was 19. Twelve of the 14 patients had femoral or pelvic fractures or both. Eight patients had orthopaedic injuries initially treated with traction. The most common complication during extracorporeal life support management was bleeding, which occurred in eight of 14 patients. Eight of the 14 patients survived. Seven of eight patients with less than 6 days of mechanical ventilation before initiation of extracorporeal life support survived. Only one of six patients with six or more days of mechanical ventilation before initiation of extracorporeal life support survived. Patients with significant orthopaedic trauma and severe pulmonary compromise have an extremely high mortality risk. Appropriate aggressive fracture management remains the most important intervention to decrease the risk of pulmonary compromise. Early initiation of extracorporeal life support can be an additional lifesaving intervention in select patients with orthopaedic trauma who have respiratory failure refractory to conventional mechanical ventilation.
Subject(s)
Extracorporeal Circulation/methods , Fractures, Bone/therapy , Life Support Care/methods , Multiple Trauma/therapy , Respiratory Insufficiency/therapy , Adolescent , Adult , Child , Child, Preschool , Female , Fractures, Bone/complications , Humans , Injury Severity Score , Male , Middle Aged , Multiple Trauma/complications , Referral and Consultation , Respiratory Insufficiency/complications , Retrospective Studies , Survival AnalysisABSTRACT
Functional outcomes and complications experienced by adult patients who underwent iliac crest bone grafting were evaluated to assess the effect of bone grafts on patient function. In addition to retrospective chart reviews, patients completed the Sickness Impact Profile and a detailed questionnaire on pain. One hundred ninety-two patients met study inclusion criteria. Major complications were recorded in four (2.4%) patients in whom infections developed requiring readmission. Thirty-seven (21.8%) patients had minor complications. One hundred nineteen of 170 patients were available for followup; of these 119 patients, 87 (73.1%) returned completed questionnaires. Thirty-three of 87 (37.9%) patients reported pain 6 months postoperatively. The incidence of pain decreased with time, with 16 of 87 (18.7%) patients continuing to report pain more than 2 years postoperatively. Proportionately more spine patients reported pain at all time points. The mean Sickness Impact Profile score for patients completing questionnaires was nine, suggesting most patients were functioning well 2 years postoperatively. The morbidity of iliac crest grafting remains substantial. Pain symptoms in this study sample seemed to last longer in more patients than earlier series have indicated. Minimizing muscle dissection around donor sites and the advent of bone graft substitutes may help alleviate these problems.
Subject(s)
Activities of Daily Living , Bone Transplantation/adverse effects , Ilium/transplantation , Pain, Postoperative/etiology , Surgical Wound Infection/etiology , Adolescent , Adult , Aged , Aged, 80 and over , Female , Humans , Incidence , Male , Middle Aged , Morbidity , Patient Readmission , Retrospective Studies , Sickness Impact Profile , Surveys and Questionnaires , Time Factors , Transplantation, AutologousABSTRACT
Lower extremity lawn-mower injuries in children result in significant morbidity with a significant financial burden to the family and society. We reviewed 24 children with lower extremity lawn-mower injuries; all mothers completed standardized psychologic assessments of their children, and 18 children were interviewed. Fifty percent of the mothers had defensive profiles on the standardized psychologic assessment, suggesting the likelihood of denial or underreporting of the child's psychologic difficulties. Therefore, we found the interview with the child to be a more accurate measure of psychologic distress. Prevention measures aimed at parents must emphasize that a child must not be allowed in a yard that is being mowed with a riding mower.
