Timing of radiotherapy in head and neck free flap reconstruction--a study of postoperative complications

The local treatment protocol of preoperative radiotherapy in head and neck cancer treatment at the Karolinska University Hospital has resulted in a unique cohort of preoperatively high dose-irradiated patients. In total 216 consecutive patients were reviewed, of whom 221 free flaps, for head and neck cancer reconstruction, were operated between 1984 and 2002. In 194 cases radiotherapy was administered preoperatively and 27 operations were performed without prior radiation. The radiation dose was 64 Gy in 147 cases, 54 Gy or less in 45 cases and uncertain in two cases. In order to study whether the time elapsed between the end of radiotherapy and surgery had any significance regarding postoperative events, the cohort was subsequently divided into three groups: patients operated on within 4 weeks (n=27), between 4 and 6 weeks (n=88) and more than 6 weeks (n=78) after the last radiotherapy session. Postoperative complications were analysed in relation to preoperative dose and timing of radiotherapy. Preoperative radiotherapy was related to an increased risk of free flap necrosis as 22 complete and eight partial flap necroses occurred in the group that had received preoperative radiotherapy and none were observed in the non-irradiated group (P<0.05). Furthermore, a linear trend of increased flap loss (P<0.001), infections (P<0.001) and delayed wound healing (P<0.001) was seen when time increased between the last radiotherapy session and surgery. The largest increase in all complication rates was seen when more than 6 weeks elapsed between last radiotherapy session and surgery. Postoperative complications were independent of the radiation dose given. Our data show an increased morbidity in free flap surgery in the head and neck region after preoperative radiotherapy. Furthermore, time elapsed between the last radiotherapy session and surgery is associated with the risk of developing postoperative complications. We strongly suggest that free flap reconstruction should be performed within 6 weeks of the last radiotherapy session.

Immobilised heparin accelerates the healing of human wounds in vivo

Locally produced growth factors are of great importance in wound healing in human skin. Wound fluid from chronic wounds contains low concentrations of growth factors possibly because of rapid degradation as a result of the high concentration of proteases. Many growth factors involved in wound healing bind to heparin and are thereby stabilised and activated. We have recently shown that heparin in combination with chitosan stimulates re-epithelialisation in an in vitro model of human wound healing. In the present study we investigated the effects of a chitosan-heparin membrane on wound healing in 10 split-thickness graft donor sites in human skin. The chitosan-heparin membrane stimulated healing of the donor sites both when judged macroscopically in a blinded fashion and when biopsy specimens from the treated and untreated parts of the wound were investigated microscopically. We hypothesise that the beneficial effects of the chitosan-heparin membrane result from slow release of heparin into the wound area which protects locally produced growth factors. The result is increased stabilisation and concentration of growth factors in the wound area, which stimulate healing. We believe that these results may be important in the treatment of wounds that are reluctant to heal.

Heparin-chitosan complexes stimulate wound healing in human skin

The effect of heparin ionically linked to chitosan on the stimulation of re-epithelialisation of full thickness wounds in human skin was investigated in an in vitro model. After seven days of incubation, heparin-chitosan gel stimulated 9/10 of the full thickness wounds to re-epithelialise compared with only 3/10 of the wounds that were covered with chitosan gel or membrane, and none of the wounds incubated without gel or membrane or with heparin solution alone. Both dermal and epidermal cells were viable after the incubation time. Furthermore, the stimulatory effect of the heparin-chitosan complexes depended on the concentration of heparin in the complex. We hypothesise that these effects are caused by stabilisation and activation of growth factors that bind to immobilised heparin.

Pedicled compared with free transverse rectus abdominis myocutaneous flaps in breast reconstruction

Two groups of patients who had undergone breast reconstruction with the transverse rectus abdominis myocutaneous (TRAM) flap after modified radical or partial mastectomy were evaluated. The type of reconstruction was either pedicled (n = 27, one of which bilateral) or free flap transfer (n = 11). In both groups there were both primary and secondary reconstructions. Flap complications were more common with the pedicled TRAM flap. There were nine partial flap necroses in the pedicle group, but only one in the free flap group. The only flap loss was a pedicled flap. In the free flap group, revision of the anastomosis was required in two patients. The free TRAM flap took longer to do than the pedicled flap. In conclusion, the two procedures yield acceptable results, but the free TRAM flap seems to be safer than the pedicled flap, thanks to the better blood supply from the inferior epigastric artery. It also allows greater freedom and versatility in moulding the reconstructed breast.

Free radial forearm flap reconstruction in surgery of the oral cavity and pharynx: surgical complications, impairment of speech and swallowing

The first 100 consecutive free radial forearm flaps used in reconstruction for oral and pharyngeal cancer were investigated. Seven re-operations took place due to circulatory impairment of the flap. Two flaps underwent partial, and four total necrosis, one of those patients died of massive haemorrhage. Post-operative infection was significantly correlated to increased time between the last radiotherapy session and surgery. All but eight patients had post-operative impairment of swallowing and all but five patients had impairment of speech articulation or hypernasality. Post-operative time spent in hospital was a range of 12-122 days (mean 37 days). The 2-year survival rate was 70% and the 5-year survival rate was 45%.

Temperature load test to increase the accuracy of laser Doppler monitoring of flaps

A heat and cold provocation test was evaluated in 10 porcine island flaps to improve the quality of monitoring flap circulation by the laser Doppler technique. When the pedicle blood flow was undisturbed there were significant increases in flow after a heat stimulus (p = 0.01), whereas no significant flow changes were noted during arterial or venous occlusion. This method can increase the accuracy of the laser Doppler technique in monitoring the circulation in skin flaps.

Influence of high and low wall shear rates on the inhibition of factor Xa and thrombin at surfaces coated with immobilized heparin

The thromboresistant function of a surface with end-point attached heparin is based upon interaction among the immobilized heparin, antithrombin, and at least factor Xa or thrombin. Heparinized arteriovenous shunts were implanted in dogs. By compressing a segment of the shunt, high and low wall shear rate regions were obtained in each shunt. After removal, the tubings were tested for their factor Xa and thrombin inhibitory capacity. It was found that on a molar basis, the factor Xa and thrombin inhibitory capacity were similar in low wall shear rate segments. In high wall shear rate segments, the thrombin inhibitory capacity was decreased, thus indicating that the AT-mediated inhibition of the serine protease is dependent on the wall shear rate.

Enhanced patency of small-diameter tubings after surface immobilization of heparin fragments. A study in the dog

The luminal surfaces of polyethylene and polyurethane tubings of 1 mm inner diameter and 1 m in length were coated with heparin by end point attachment and thereafter sterilized in ethylene oxide. The tubings were inserted as arterio-venous shunts from the aorta to the superior caval vein via a carotid artery and a jugular vein. Patency was assessed with an ultrasound doppler flow meter and flow measurements. All nonheparinized shunts occluded within 10 days with a mean elapsed time from the insertion of the tubing is the last positive doppler registration being 3.5 days. The corresponding patency time for heparinized shunts was 25.9 days. The occlusion of the heparinized tubings was due to the incorporation of the ends of the tubings in the walls of aorta and caval vein, whereas the nonheparinized tubings occluded as a result of clot formation. It is concluded that surface immobilization of heparin with sequences capable of activating antithrombin may be beneficial in the development of small-diameter vascular protheses.

Influence of blood flow and the effect of protamine on the thromboresistant properties of a covalently bonded heparin surface

Polyethylene tubings, 2-mm inner diameter and the length of 1 m, untreated or furnished with a covalently bonded heparin surface layer, were inserted as arteriovenous shunts bilaterally in dogs. By compressing the middle part, the initial blood flow was adjusted to 10 or 40 mL/min. The thrombogenicity of the tubings was assessed by the patency of the shunts and by assaying the generation of fibrinopeptide A (FPA) in arterial blood and in blood after its passage through the shunts. In untreated shunts clotting rapidly occurred preceded by high FPA generation in blood passing through the shunts. The blood flow in heparinized shunts remained unchanged throughout the test period. At the low flow rate a certain degree of FPA generation in the shunts occurred. At the high flow rate no changes in FPA levels occurred. The function of the heparin surface is thus flow rate dependent. Systematic heparinization and subsequent neutralization with protamine or administration of protamine alone did not interfere with the function of the heparin surface.

Long-term stability in vivo of a thromboresistant heparinized surface

A surface with covalently bonded heparin was tested in an in vivo model. Heparinized and non-heparinized tubings were inserted in the pig aorta. They were left in place for up to 16 wk. After removal they were analysed for their capacity to take up and inhibit thrombin. A comparison was also made with tubings that had not been inserted in animals. The heparin surface showed some specific alterations after implantation but its capacity to inhibit thrombin was not impaired. The heparinized tubings caused less intimal hyperplasia and thrombi than non-heparinized tubings.

Reconstruction in the head and neck regions with free radial forearm flaps and split-rib bone grafts

Fifty patients with wound defects in the head and neck region underwent reconstruction with the free radial forearm flap. Mandible defects in 17 patients were reconstructed by split-rib bone grafts. Radiotherapy was administered to 44 patients preoperatively. The free flap was successful in 49 patients, and there was one case of partial flap necrosis. The free flap is soft, thin, and movable. The split-rib bone graft was successful in 15 patients, and there was one case of partial graft necrosis and one case of complete necrosis. Postoperative complications were decreased by 50 percent when compared with the complication rate when split ribs were covered by forehead flaps, deltopectoral flaps, or oral mucosa. Finally, the functional and cosmetic results were excellent.

Sensibility and cutaneous reinnervation in free flaps

Sensibility and sensory reinnervation were investigated in 19 free flaps, predominantly located on the lower extremities, between 2 months and 3 years after flap transfer. All patients showed deep pressure sensibility. In 10 of the patients, primarily those examined late after surgery, a heat pain threshold was obtained at about 50 degrees C. None of the patients had superficial sensibility of any other modality. No neurofilament-positive sensory nerve fibers were observed in the dermis or epidermis. In one patient nerve fibers were detected in the subcutaneous tissue. It is concluded that patients will have deep pressure sensibility of the flap area even early after the operation and that most patients will develop a heat pain sensitivity, probably due to subcutaneous reinnervation.

Excitability in free muscle transfers: an optimal method of monitoring tissue circulation?

Recent methods of postoperative monitoring of free muscle transfers were used in 4 patients operated on with free revascularized gracilis muscle. The contractility/electromyographic (EMG) activity in response to electrical stimulation was used as an index of viability, i.e., intact circulation. However, during operations it was observed that contractions as well as EMG potentials could be evoked 1 to 2 hours after blood flow had been arrested. Muscle excitability was further studied in the gracilis muscle from a patient who had undergone hemipelvectomy; it was found that contractility and EMG potentials were evoked at least 4 hours after circulatory arrest. It thus seems that loss of muscle excitability is not as early a sign of impaired blood supply as recently has been suggested. Spontaneous EMG activity, which can be recorded 2 to 3 weeks after denervation, is reported to be affected earlier than muscle excitability by circulatory arrest. Thus, the recording of spontaneous EMG activity in previously denervated muscles is proposed as an alternative and simple electrophysiological method for post-operative monitoring of vascularization in free muscle transfers.

Prediction of skin flap necrosis: a comparative study between laser Doppler flowmetry and fluorescein test in a rat model

Cranially based dorsal skin flaps were raised in a rat model. Fluorescein test and laser doppler flowmetry were used to predict the level of necrosis. The actual border of necrosis after one week was compared with the laser doppler flowmetry prediction: A high correlation (0.96) was found. The two methods also correlated well with each other (0.96).

Toxic shock syndrome after augmentation mammaplasty

Toxic shock syndrome was first described in children in 1978. Two years later the strong connection between this disease and the colonization of vaginal tampons with certain strains of Staphylococcus aureus was noted. Even from the earliest descriptions, however, it has been clear that the same clinical picture may be caused by staphylococcal infections elsewhere, and that the presence of foreign materials in the body is not mandatory. We describe a patient with toxic shock syndrome after augmentation mammaplasty.

Thrombin uptake and inhibition on endothelium and surfaces with a stable heparin coating: a comparative in vitro study

The endothelial lining and two differently heparin-coated surfaces were compared in vitro regarding thrombin uptake and inhibition. One heparin surface was based on stabilized ionic binding of heparin, the other on covalent binding of partially degraded heparin. Both heparin surfaces have previously been shown to have pronounced thromboresistant properties. The two heparinized polyethylene surfaces and the endothelial surface of segments of the porcine aorta were studied. After exposure to the surfaces, thrombin disappeared from the solution and appeared bound to the surfaces. The disappearance rate of thrombin from the solution was the same on exposure to the endothelium and the covalently bonded heparin surface, but less following exposure to the ionically bonded heparin surface. The thrombin activity appearing on the endothelium was lower than on the heparin surfaces, indicating that the endothelium exerted a slow thrombin inhibiting capacity. On exposure of the thrombin-loaded endothelium to plasma, thrombin was rapidly inhibited. Thrombin bound to the covalently bonded heparin surface was inhibited at a slower rate than on the ionically bonded surface, but still faster than the rate at which free thrombin was inhibited in nonheparinized plasma. It is concluded that the endothelium and stabilized heparin coatings bind thrombin and accelerate its inhibition by plasma.

Laser Doppler surveillance of the circulation of free flaps and replanted digits

In a series of 40 clinical free flaps and replantations the laser doppler technique has been used successfully for postoperative surveillance of circulation. A uniform flow pattern was obtained from all uncomplicated cases contrasting to the flow pattern seen in cases with thrombotic complication. The laser doppler continuously records flow of the microcirculation and is able to monitor blood flow in all types of free tissue transfer presently used as well as replantations. The laser doppler has effectively diagnosed two arterial thromboses with a characteristic flow pattern. It can distinguish venous from arterial occlusion. It can record flow in skin flaps which are difficult to judge clinically and in buried flaps, where no clinical observations are possible. The laser doppler should be used in conjunction with routine clinical observations.

Long-term monitoring of arterial pO2 in burned patients

Five patients, who were treated in a special ward for burns were followed by continuous intra-arterial pO2 monitoring for a total of 1612 h (range 13-604 h). The pao2 catheter electrodes used were surface-heparinized, and inserted either in the radial or the femoral artery. Some electrodes were accidentally withdrawn. Recalibration was performed for two of the 10 electrodes used. These electrodes presented a changed sensitivity after heavy stretching of the sensor during the nursing. The sensitivity of one of these electrodes was altered downwards and the other one upwards. After recalibration the pao2 electrodes presented accurate values for the rest of the monitoring period. Without compensation for drift, the pao2 electrode readout was compared to the results of traditional blood-gas analysis, which served as a reference. The regression function found was y = -0.62 + 1.04 chi (r = 0.93, SD = 1.40, n = 60). The blood flow velocity around some of the pao2 electrodes was studied by the pulsed Doppler technique. There was no influence of the surface-heparinized pao2 electrode on the femoral artery blood flow velocity as compared to the contralateral, non-catheterized femoral artery. The blood flow velocity proximal to a traditional radial artery catheter was compared to the flow velocity in the contralateral radial artery containing a surface-heparinized pao2 electrode. The surface-heparinized electrode did not decrease the mean flow velocity in contrast with the traditional radial artery catheter, which had to be withdrawn after 8 days because of clotting. The surface-heparinized catheter electrode was still monitoring pao2 accurately after 25 days in the artery, which was the longest period studied for a particular sensor.

Effect of dipyridamole on the survival of experimental critical skin flaps

The effect of dipyridamole (Persantin) on the survival of experimental skin flaps was studied. In controls 39% of the skin flap area survived. Intraperitoneal injection of dipyridamole 4 mg/kg twice daily starting four hours preoperatively increased the surviving area with 18%. This increase is statistically significant (p less than 0.05). The improved survival could be due to the vasodilatory action of the drug and/or proliferation of small bloodvessels induced by the drug.

Studies of teratogenic effects of the dithiocarbamates maneb, mancozeb, and propineb

Oral administration of high dosages of the dithiocarbamate pesticides maneb and mancozeb was teratogenic in rats but not in mice. The malformations, severe limb and craniofacial defects, were pronounced after maneb treatment but less so after mancozeb and propineb, zinc-containing compounds. The teratogenic effect of maneb was progressively reduced by simultaneously administering increasing amounts of zinc acetate. The mechanism of the teratogenic effect may involve the compounds being chelating agents, trapping zinc required for many important enzyme systems.

Transfixation in cross-leg procedures using Hoffman's instruments. Report of forty-two cases

The Hoffman transfixation equipment for fracture fixation gives simultaneously an excellent fixation of a flap in cross-leg procedures. Because of these favourable results in 42 cases this method for the fixation of the extremities in predicle flap procedures is recommended. It is possible to divide the flaps much earlier than is customary. In this material half of the flaps were divided on the 14th day or earlier. One or two preoperative flap delays are recommended. The method produces safer and faster healing of the flap.