Oxygen tension in zones of the epiphyseal plate, the metaphysis and diaphysis. An in vitro and in vivo study in rats and rabbits.
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Animals↗
Biomedical subjects
R B Heppenstall
Publications and source records attributed to R B Heppenstall.
The effect of chronic hypoxia on wound healing.
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Animals↗
Tissue gas tensions and oxygen consumption in healing bone defects.
A technique for measuring the gaseous environment during the reconstitution of a large bone defect is described. Extensive testing of this system over the past 10 years has demonstrated its validity in measuring the average extracellular tissue pO-2 and pCO-2. Histology of the tissue surrounding the tonometer was obtained and correlated with the gaseous measurements. New bone formation in the healing segmental bone defects has been shown to take place under hypoxic conditions. The oxygen consumption of the surrounding tissue was determined and correlated with the histology and tissue gas measurements. It was demonstrated that the oxygen consumption was not elevated during the period of new bone formation, reflecting a state of anaerobic metabolism. The hypoxic conditions persist until the vascularity increases to match the cellularity. Thephysiological role of oxygen in osseous repair is presented. The present technique as well as the previously published microelectrode technique have demonstrated bone formation in vivo can take place under hypoxic conditions but the mechanism is not known and requires further investigation.
Animals↗
Computed tomographic scanning of cervical spine fractures: does it influence treatment?
OBJECTIVE: To determine whether the superior sensitivity of computed tomography (CT) results in changes in treatment plans for cervical spine fractures that have been diagnosed on plain films alone. DESIGN: Retrospective review of radiographic studies for cervical spine trauma. SETTING/PARTICIPANTS: An orthopaedic spine surgeon (SS), an orthopaedic traumatologist (OT), an orthopaedic spine fellow (SF), and an orthopaedic chief resident (CR) were independently presented thirty-nine cases of cervical spine trauma imaged with adequate plain radiographs and with CT. MAIN OUTCOME MEASURES: Agreement was measured by calculation of kappa coefficients. RESULTS: The detection rate of total fractures on plain radiographs alone ranged from 47 percent to 71 percent, and the diagnosis changed an average 53 percent of cases. Change in treatment plans ranged from 10 percent (SS) to 46 percent (CR) of cases. Of these changes, undertreatment occurred as follows: SS =3 percent, OT =8 percent, SF =36 percent, and CR = 46 percent. The mean kappa coefficient for intraobserver agreement of treatment plans was 0.69. The experienced observers demonstrated "excellent" agreement with an average kappa coefficient of 0.85, whereas the mean coefficient for inexperienced observers was 0.54 or "moderate" agreement. Complete diagnostic agreement occurred between the experienced observers after review of both the plain films and CT scans. The interobserver agreement of treatment plans for the experienced observers increased from 0.79 to 0.88. CONCLUSIONS: CT scanning afforded additional information for all observers. Experienced observers can reliably determine treatment plans for cervical spine trauma diagnosed on plain films alone, whereas inexperienced observers are less reliable. For the experienced observers, interobserver agreement on treatment plans increased after the addition of CT.
Cervical Vertebrae↗
Well-leg compartment pressures during hemilithotomy position for fracture fixation.
OBJECTIVE: To evaluate the relationship between the well-leg compartment pressures and time during hemilithotomy position for fracture fixation. DESIGN: Prospective. SETTING: Level 1 trauma center. PATIENTS/PARTICIPANTS: Ten patients who underwent intramedullary nailing of a fractured femur in the hemilithotomy position (with a well-leg holder). INTERVENTION: Continuous pressure monitoring was achieved with in-dwelling slit catheters inserted into the calf compartments of the well leg. Baseline measurements were obtained in the supine position. After the leg was placed in the hemilithotomy position, compartment pressures were monitored throughout surgery. MAIN OUTCOME MEASUREMENTS: Calf compartment pressures at baseline, during hemilithotomy position, and post-hemilithotomy were compared. The association between body mass index and compartment pressure was analyzed. RESULTS: A consistent pattern was observed between compartment pressures and time. The curve was that of a step function in which the pressure increased as soon as the leg was placed in the well-leg holder and remained elevated until the leg was taken down. The pressure jumped from a baseline of 9.2 to 27.3 millimeters of mercury (mm Hg) (p<0.0001). While in the hemilithotomy position, the leg pressure trended slightly upward. Once the leg was taken down, the pressure immediately returned to a near-baseline level of 8.1 mm Hg (p<0.0001). A significant correlation was also found between the body mass index and leg pressure (R2 = 0.713; F = 0.002). CONCLUSIONS: The use of the well-leg holder to maintain hemilithotomy position increases the calf compartment pressures dramatically and significantly. Therefore, we recommend avoiding this position for fracture fixation in at-risk patients.
Adolescent↗
Detection of synovial pseudarthrosis by 99mTc scintigraphy: application to treatment of traumatic nonunion with constant direct current.
A prospective study utilizing technetium scintigraphy to evaluate nonunion patients prior to the electrical stimulation of osteogenesis is reported. Roentgenographic evaluation and scintigraphy must include four views (anteroposterior, lateral and both obliques). Although all nonunion technetium scans showed increased uptake of the radionuclide at the fracture site, three bone scan patterns were identified: (1) intense, uniformly increased uptake at the nonunion site (69.5%); (2) photon deficient (cold) cleft between two intense areas of uptake (23.4%); and (3) indeterminate pattern (7.1%). The presence of a cold cleft between two intense areas of uptake on scintigraphy correlated closely with the presence of a synovial pseudarthrosis at surgery. Nonunions of the humerus were most frequently associated with synovial pseudarthrosis (57.1%). The presence of a synovial pseudarthrosis as suggested by technetium scintigraphy mandates open excision of the lining membrane at the time of electrode insertion.
Diphosphonates↗
Fracture healing in the presence of anemia.
In experimental fractures in rabbits, a decrease in blood volume associated with anemia delays healing, but uncomplicated normovolemic anemia has no adverse effect. For the purpose of stimulating the repair process in normovolemic anemia individuals blood transfusions would be ineffectual.
Anemia, Hemolytic↗