Laser discectomy: a review.

The percutaneous treatment of lumbar disc disease with laser energy has emerged recently as an alternative to open surgical or even mechanical percutaneous methods. Although numerous laser wavelengths have been employed in both the experimental and clinical settings, no consensus exists regarding selection of laser, treatment duration, or energy requirements. Inspection of the disc/water absorption spectrum combined with the limitations of the fiberoptic delivery systems argue for the use of lasers near 2.0 microns, such as the 2.1-microns Ho:YAG. Although recently developed in vitro models have allowed for laser system comparisons, most clinical work has been empiric, uncontrolled, and in very small series.

Comparison of the effects of total blood substitution during two different levels of hypothermic cardiac arrest.

The effect of total blood replacement with a solution containing neither hemoglobin nor fluorocarbon was studied under two different levels of hypothermia. Ten dogs were anesthetized and esophageal temperature lowered to about 24 degrees at which time exsanguination began. Upon cardiac arrest and the completion of exsanguination, continuous whole body closed chest extracorporeal circulation of an oxygenated blood substitute was begun. Hematocrit was 1% while core temperature remained less than 10 degrees C for 3 hours of perfusion during which nadirs of 1.3 degrees C (Group I, N = 5) and 7.3 degrees (Group II, N = 5) were achieved. Replacement of the perfusate with whole blood began once the dog was rewarmed to approximately 10 degrees C. All dogs survived the procedure. Two dogs from each group died by the fourth post-operative day but the others survived long term. Group II showed a faster return to normal based on motor behavioral, biochemical and hematological changes. Thus the combination of profound hypothermia and complete blood substitution with a solution lacking any special oxygen carrying molecule, can be tolerated for 3 hours using both levels of hypothermia, however, the warmer one appears to be associated with faster recovery.