Microdialysis in the femoral head of the minipig and in a blood cloth of human blood

Abstract

Introduction Microdialysis can detect ischemia in soft tissue. In a previous study, we have shown the development of ischemia in the femoral head removed from patients undergoing total hip replacement. That study also raised some methodological questions that this study tries to answer: what is happening in the dead space around the catheter in the drill canal, and is there an equilibrium period after the insertion of the catheter?Material and methods In an ex-vivo study using 5 syringes with 5 mL human blood, a microdialysis catheter was inserted and microdialysis was performed over 3 h. In an in-vivo study, a drill hole was made in the proximal part of the femur in 6 mature Göttingen minipigs and microdialysis was performed over 3 h. The pigs were kept normoventilated during the experiment.Results The ex-vivo microdialysis results showed that lactate kept a steady level and glucose and glycerol both fell; pyruvate fell but leveled out. The mean lactate/pyruvate ratio increased from 13 (SD 4) to 32 (SD 6) (p < 0.001). In vivo, relative recovery was 57% (SD 11). Lactate increased, pyruvate stayed constant, and glucose and glycerol levels fell. The lactate/pyruvate ratio increased from 30 (8) initially to 37 (8) after 1 h (p = 0.007) but no statistically significant change from 1 to 2 h was observed.Interpretation The ex-vivo study showed a clear washout pattern, and was different from what we see in bone. The in-vivo study indicated that an equilibrium period is necessary or that a reference measurement in healthy bone must be used when performing short measurements in bone.

Microdialysis for the Assessment of Intervertebral Disc and Vertebral Cancellous Bone Metabolism in a Large Porcine Model

“…For vertebral cancellous bone, ischemic conditions have not previously been shown. However, these findings are consistent with previous microdialysis results of ischemia in bone demonstrated in the femoral head of both humans and pigs (12)(13)(14). Altogether, the findings from the present study confirms previous findings of ischemia in bone and the intervertebral disc.…”

“…Glycerol is liberated as a result of cell membrane damage. As previously demonstrated, the trauma of drilling in bone tissue results in initially elevated glycerol concentrations (12)(13)(14). The lowest mean glycerol concentrations were found in the intervertebral disc, which may be explained by a lower number of cells in this compartment.…”

“…Microdialysis as a method is, among others, advantaged by dynamic and simultaneous in vivo sampling from multiple compartments of the unbound water-soluble molecules from the interstitial space of the investigated tissue (9,10). For the particular cases of bone tissue and the intervertebral disc, microdialysis has only been applied for the assessment of metabolism in the femoral head of humans and pigs, and in a cadaver study, respectively (11)(12)(13)(14). To date, microdialysis sampling from vertebral cancellous bone and the intervertebral disc has been limited to antimicrobials in a porcine model (15,16).…”

Intraosseous microdialysis for bone free flap monitoring in head and neck reconstructive surgery: A prospective pilot study

“…Bøgehøj et al (2007) used microdialysis to evidence the development of ischemia in femoral heads removed from patients undergoing total hip replacement. Next, the researchers explored the phenomenon in the dead space around the catheter in the drill canal and concluded that (a) an equilibration period of 2 hr is necessary so that the measured values are representative of the bone metabolism, and (b) a reference measurement in healthy bone must be made (Bøgehøj, Emmeluth, & Overgaard, 2011). In the present study, the mean equilibration period was 5 hr and 5 min; however, the specific metabolic pattern of bone tissue must be taken into account.…”

High Cefuroxime Concentrations and Long Elimination in an Orthopaedic Surgical Deadspace—A Microdialysis Porcine Study

“…Relative recovery (%) = As microdialysis must be introduced into drill holes in bone, concerns have been raised whether microdialysis sampling of antibiotics actually reflects bone concentrations, a mixture of concentrations originating from the bone and the adjacent tissues or a blood clot filling the dead space around the probe. Three separate and independent studies have investigated these matters, indicating that the measured concentrations in drill holes in bone do reflect the actual bone concentrations [47][48][49]. Moreover, sampling from drill holes seems to reflect the true orthopaedic peri-and postoperative conditions.…”