The effect of acute hyperbaric oxygen therapy on axial pattern skin flap survival when administered during and after total ischemia.

The effect of hyperbaric oxygen (HBO) on axial pattern skin flap survival in male Wistar rats, when administered during and immediately following prolonged total flap ischemia, was evaluated. Eighty-one 3 x 6 cm rectangular epigastric skin flaps were elevated, and the inferior epigastric pedicle of each flap occluded for 8 hr. The animals were divided into a control and three other experimental groups: Control (n = 27) -8 hr flap ischemia, no HBO; Group (n = 21) - HBO therapy (100 percent O2--three 1.75 hr dives at 2.5 atm) during ischemia; Group 2 (n = 21) - HBO therapy (two 1.75 hr dives) following ischemia; Group 3 (n = 12) - HBO treatment during ischemia but with the flap contained in a metal-coated Mylar bag to prevent oxygen diffusion. The percentage of flap necrosis was calculated on postoperative day 6. Mean flap necrosis for controls was 28 percent (+/- 21 S.D.), while HBO treatment during ischemia or during reperfusion significantly reduced this necrosis to 9 percent (+/- 11) and 12 percent (+/- 14), respectively (p less than 0.01). The percentage of necrosis for Group 3, with the local with the local effect of HBO on the flap blocked by the diffusion barrier, was 5 percent (+/- 7), also significantly better than the controls (p less than 0.0005) but no different from the other two experimental groups. HBO treatment increases the percentage of axial pattern skin flap survival when administered during or immediately following total flap ischemia. The improved flap survival appears to be a systemic and not a local effect.

Synergistic effects of pentoxifylline and hyperbaric oxygen on skin flaps.

This study investigated the effects of pentoxifylline and hyperbaric oxygen (HBO) on experimental skin flaps in rats under four conditions. Sixty animals were randomly divided into one of four groups: (1) a control group, (2) a pentoxifylline- or (3) an HBO-treated group, and (4) a pentoxifylline- plus HBO-treated group. Cranially based skin flaps were elevated on the dorsum. The surviving length was evaluated with fluorescein dye seven days after the operation. Rats that were treated with pentoxifylline received 20 mg/kg intraperitoneally at 24, 12, and 1 hour(s) before flap elevation and every 12 hours after the operation for seven days. Rats that were treated with HBO received a total of 14 two-hour treatments at 2.5 absolute atmospheres in divided doses. Results indicated that the surviving length of flaps in the pentoxifylline- or HBO-treated groups was significantly greater than those in the control group, but were not significantly different from each other. Animals treated with both pentoxifylline and HBO had significantly greater flap survival than animals in any of the other three groups. This reflected a 30% to 39% improvement over pentoxifylline alone- or HBO alone-treated animals, and an 86% improvement over control animals. Mechanisms of action for this apparent synergistic effect on flap survival are discussed.

Applications of hyperbaric oxygen for the otolaryngologist--head and neck surgeon.

In the last 10 years, the use of hyperbaric oxygen (HBO) in clinical medicine has increased dramatically. Despite its controversial beginnings, it has won acceptance as a treatment for specific diseases in both medical and surgical patients. The purpose of this article is to familiarize the otolaryngologist-head and neck surgeon with the currently accepted applications of HBO and to present some promising investigational uses of this therapy.

Effects of hyperbaric oxygen and irradiation on experimental skin flaps in rats.

This study investigated the effects of hyperbaric oxygen (HBO) and irradiation (RT) on experimental skin flaps in rats under varying conditions. Animals were assigned at random to 1 of 15 groups that represented all possible ordering effects of HBO, RT, and flap, as well as controls that included flap-only, RT-only, and HBO-only groups. Cranially based skin flaps measuring 3 x 9 cm were elevated on the dorsum. The surviving length was evaluated with fluorescein dye 7 days after the operation. Rats receiving HBO were subjected to four consecutive 2-hour treatments of 100% oxygen at 2.5 atmospheres with half-hour intervals of room air. Depending on the treatment condition, HBO was given either 48 hours or 24 hours before flap elevation, or within 4 hours or 48 hours after flap elevation. Rats receiving RT (60Co) were given a single dose of 1000 rads to the dorsum. Results showed that all groups receiving HBO within 4 hours after flap elevation had significantly greater flap survival length (P less than .05), with as much as a 22% greater length of surviving flap. HBO given 48 hours before flap elevation also significantly improved flap survival over controls (P less than .05). RT appeared to have no immediate significant effect on flap survival. However, rats receiving RT, regardless of other factors, gained significantly less weight than did controls (P less than .001). Findings clearly indicate that, to be effective, HBO needs to be given as soon after surgery as possible.

Extralaryngeal divisions of the recurrent laryngeal nerve. Surgical and clinical significance.

Extralaryngeal branches of the recurrent laryngeal nerve have been noted in the literature, but frequently the researchers fail to indicate with accuracy the site of bifurcation. The current study was undertaken to designate the exact level of bifurcation of the recurrent laryngeal nerve, with more precise localization using a standard anatomic landmark. A prospective study based on 83 surgical patients was performed. The location of all nerves was measured using the inferior border of the cricoid cartilage as the anatomic landmark. A total of 153 recurrent laryngeal nerves were observed. Sixty-three (41.2 percent) bifurcated or trifurcated into extralaryngeal branches. Of these, there were four instances of trifurcations. The remaining 59 nerves bifurcated. Of these, 14 nerves bifurcated into equal-sized branches which went in an anterior or posterior direction. The remaining 45 nerve bifurcations indicated that 39 (86.7 percent) of the small branches went in a posterior direction, whereas only 6 (13.3 percent) of the large branches went in that direction. Surgical and clinical implications of this finding were discussed. Two instances of a "nonrecurrent" laryngeal nerve (that occurred on the right side) were also noted. The results of this study demonstrate conclusively that extralaryngeal branches of the recurrent laryngeal nerve are not an anatomic rarity. Therefore, thyroid surgery must include identification and preservation of the recurrent laryngeal nerve and all of its divisions.