Göran Nylander

Hyperbaric Oxygen Treatment Enhances Regeneration of the Rat Sciatic Nerve

The effect of hyperbaric oxygen (HBO) treatment on regeneration of the rat sciatic nerve was studied. The sciatic nerve was crushed with a pair of pliers and the animals were either left untreated or subjected to a series of 45-min exposures to 100% O2 at 3.3 atm absolute pressure at 0, 4, and 8 h postoperatively and then every 8 h. Regeneration was evaluated using the pinch-reflex test at 3, 4, or 5 days following surgery and with neurofilament staining at 4 days. The regeneration distances at all time points were significantly longer in animals exposed to hyperbaric oxygen treatment independent of the evaluation procedure. A short initial period of the same HBO treatment schedule, with no more treatments after 25 h, appeared as effective as when treatments were maintained being given every 8 h until evaluation. We conclude that HBO treatment stimulates axonal outgrowth following a nerve crush lesion.

The UNILINK system for mechanical microvascular anastomosis in hand surgery

A new mechanical anastomotic device--the UNILINK system--for small vessels, designed for work under the operating microscope was used in four patients for microvascular, hand surgical operations. All procedures were successful with regard to tissue survival and wound healing. Basal skin temperature and systolic blood pressure distal to the mechanical anastomoses were normal 12 to 26 months after the operation. Doppler investigation also confirmed that all mechanical anastomoses were patent. At the time of this report, 32 to 45 months after the operations, no adverse effects of the method have been found. The device offers increased safety and speed in microvascular operations.

Hyperbaric oxygen reduces ischemia-induced skeletal muscle injury.

&NA; The effect of hyperbaric oxygen treatment on skeletal muscle submitted to 3 or 4 hours of ischemia was studied in a rat hindlimb model after 48 hours of reperfusion. Forty‐eight male Sprague‐Dawley rats were allocated to four groups. In the two treatment groups, hyperbaric oxygen was given for 15 minutes at 2.2 atm immediately and 4, 8, 16, 24, 32, and 10 hours after release of the ischemiainducing tourniquet. The injury to skeletal muscle was quantified from the uptake of 99mtechnetium‐pyrophosphate injected intravenously after 15 hours of reperfusion) in anterior tibial muscle harvested 3 hours later. The uptake was significantly lower in hyperbaric oxygentreated rats than in untreated rats with 3 or 4 hours of ischemia (p < 0.01 and p < 0.05). After 4 hours of ischemia, the changes in levels of the intracellular muscle compounds adenosine triphosphate, phosphocreatine, and lactate were less in the hyperbaric oxygen—treated rats than in the untreated animals.

Lipid Peroxidation Products in Postischemic Skeletal Muscle and After Treatment with Hyperbaric Oxygen

Earlier studies from our laboratory have shown that hyperbaric oxygen (HBO) treatment reduces edema, enhances aerobic metabolism and improves the recovery of the phosphorylase activity in postischemic rat skeletal muscle. However, as it has become increasingly apparent that oxygen in excess may have harmful effects, it was of interest to study if HBO caused an increased formation of oxygen free radicals. Toxic peroxides, as a result of oxygen free radicals, were quantitated in the postischemic skeletal muscle of rat and with HBO treatment by measuring the thiobarbituric acid reaction which includes the lipid peroxides and the alkydes including malondialdehyde (MDA), a key intermediate in the formation of peroxides. A tourniquet model of temporary ischemia of the rat hindlimb was used for 3 hours. Muscle biopsies were taken at various intervals before and after tourniquet release with and without hyperbaric oxygen at 2.5 atmospheres absolute (ATA) for 45 min after tourniquet release. Three hours of anesthesia caused a significant rise of thiobarbituric acid reactive material (TBAR) concentration in muscle compared to normal controls without anesthesia. An increase of similar magnitude was seen after 3 hours of ischemia, with or without reperfusion. These values were normalized after 45 min. HBO in the postischemic phase did not cause a further increase in the TBAR concentration in muscle immediately postischemically. However, the levels remained increased at 45 min after the onset of reperfusion, immediately after HBO treatment and had returned to normal values 2 hours postischemically.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of hyperbaric oxygen treatment in post-ischemic muscle. A quantitative morphological study.

In the post-ischemic muscle, hyperbaric oxygen (HBO) treatments have been shown to reduce post-ischemic edema and enhance aerobic metabolism. In the present paper histological, histochemical and ultrastructural methods were used to study the influences of HBO treatment on the morphology of post-ischemic skeletal muscle. The changes were also quantified using morphometry. The circulation of the rat hindlimb was interrupted for 3 hours and muscle biopsies were taken 5 and 12 hours post-ischemia. Light microscopy showed signs of ischemic changes in the muscle. Morphometrically, the area with activity of the muscle enzyme phosphorylase was greatly reduced post-ischemia. HBO treatment at 2.5 atmospheres of absolute pressure (ATA) for 45 min significantly increased muscle cross sectional area with a positive phosphorylase reaction 5 hours post-ischemia. Three HBO treatments were necessary to maintain this effect, 12 hours post-ischemia. Ultrastructurally, the ischemic changes seen using light microscopy were confirmed. Morphometrically, there was a significant increase of mitochondrial size in the ischemic muscle compared with the control uninjured muscle but HBO did not markedly reduce these ultrastructural changes. It was concluded that the reduction of phosphorylase activity, a sensitive marker for muscle cell damage, is to a great extent prevented by HBO treatment in the post-ischemic phase.

Altered glutathione levels in ischemic and postischemic skeletal muscle : Difference between severe and moderate ischemic insult

The purpose of the present study was to investigate how the duration of ischemia and reperfusion affect the glutathione (GSH) levels in skeletal muscle and to assess the presence of oxidative stress by quantitating oxidized glutathione (GSSG) and the ratio of GSSG/GSH. The amounts of GSH and GSSG were quantitated in the tibialis anterior muscle of the rat hind limb after 2 and 4 hours of tourniquet ischemia and after 1 and 5 hours of reperfusion, and the levels were compared to those in nonischemic control tibialis anterior muscles. In muscles subjected to 2 hours of ischemia, the levels of GSH, GSSG, and the ratio GSSG/GSH did not differ significantly from those of nonischemic controls. After 4 hours of ischemia without reperfusion, the GSH levels were slightly increased, compared to controls (p < 0.05). After 1 hour of reperfusion following 4 hours of ischemia, the levels of GSH decreased by 50% compared to control (p < 0.01), and still after 5 hours of reperfusion the levels of GSH were 50% lower than control levels. The GSSG/ GSH ratio did not change during 1 and 5 hours of reperfusion compared to control. A major finding in this study was that, during reperfusion after severe ischemia of 4 hours, there was a marked depletion of glutathione, which was not seen after a moderate ischemic insult of 2 hours.

The Niebauer-Cutter Prosthesis in Excision Arthroplasty of the Trapezium

Sixteen patients had excision arthroplasty of the trapezium, using the Niebauer-Cutter prosthesis. The average period of postoperative follow-up was thirteen months. All patients had severe preoperative disabilities and the majority were relieved from resting pain and pain during active use of their hands. The postoperative range of motion with regard to the palmar and radial abduction was found to be satisfactory, while varying degrees of limitation of circumduction was the rule. There was no correlation between the patients’ own judgment of the postoperative benefits and the objectively measured range of motion. One patient had a luxation of the prosthesis, while another had a subluxation when opposing the thumb. This frequency of luxation/subluxation seems to be less than that experienced with the other common type of prosthesis, the Swanson prosthesis. Although it is obvious that the ideal prosthesis for treatment of disabilities in the carpometacarpal joint of the thumb is still not available, it was concluded that the Niebauer-Cutter prosthesis is the best choice at the present.

Patient-reported outcome of surgical treatment of nerve entrapments in the proximal forearm

The outcome of decompression for long-standing symptoms of nerve entrapments in the proximal forearm was investigated in a retrospective study of 205 patients using a self-assessment questionnaire, 45 months after the operation. The questionnaire consisted of visual analogue scale recordings of pre- and postoperative pain during rest and activity, questions about remaining symptoms and appreciation of the result and the Disabilities of Arm, Shoulder and Hand form (DASH). Altogether, 59% of the patients were satisfied, 58% considered themselves improved, and 3% as being entirely relieved of all symptoms. Pain decreased significantly (P = 0.001). There was a significant correlation between preoperative duration and patient perceived post-operative pain. Preoperative pain was a chief complaint, and pain reduction appears to be the principal gain of the operation. Although the majority of the patients benefited from the operation, a substantial proportion was not satisfied. There is apparently room for improvement of the diagnostic and surgical methods applied in this study.