Oral hygiene in the control of occlusal caries

In order to be able to objectively evaluate capillary perfusion of venous flaps, we created arterialised venous flaps, venous flow-through flaps, and unilateral pedicled venous island flaps in the epigastric vascular system of Wistar rats and determined their oxygen supply with two different methods. Interstitial pO2 was polarographically measured with a probe placed intracutaneously in the center of the 4 x 2.5 cm flaps and continuously recorded on a connected computer. Moreover, we also noninvasively determined the oxygenation of the intracapillary haemoglobin with a micro-lightguide spectrophotometer. The statistical evaluation showed comparable results for both measurement methods: Arterialised venous flaps had a better oxygen supply with a pO2 of 16 mmHg and an Hb oxygenation of 23% than the other types of venous flaps, but they have a poorer oxygen supply than conventionally perfused flaps (pO2: 24 mmHg, Hb oxygenation: 30%). Venous flow-through flaps (pO2: 9 mmHg, Hb oxygenation: 17%) and unilateral pedicled venous island flaps had a significant better oxygen supply than skin flaps without any vascular connection. The results show that the capillary system in all types of venous flaps is reached by some of the inflowing oxygenated haemoglobin over the entire flap surface to different degrees.     

A comparison of resource costs for head and neck reconstruction with free and pectoralis major flaps

A series of 178 immediate reconstructions with regional or distant tissue for repair of oropharyngeal defects caused by treatment of head and neck cancer was reviewed to determine whether reconstruction with free flaps was more or less expensive than reconstruction with regional myocutaneous flaps. In this series, three types of flaps were used: the radial forearm free flap (n = 89), the rectus abdominis free flap (n = 56), and the pectoralis major myocutaneous flap (n = 33). Resource costs were determined by adding all costs to the institution of providing each service studied using salaried employees (including physicians). The two free-flap groups were combined to compare free flaps with the pectoralis major myocutaneous flap, a regional myocutaneous flap. Failure rates in the two groups were similar (3.0 percent for pectoralis major myocutaneous flap, 3.4 percent for free flaps). The mean costs of surgery were slightly higher for the free flaps, but the subsequent hospital stay costs were lower. Therefore, the total mean resource cost for the free-flap group ($28,460) was lower than the cost for the myocutaneous flap group ($40,992). The pectoralis major myocutaneous flap may have been selected for more patients with advanced disease and systemic medical problems, contributing to longer hospitalization and added cost. Nevertheless, this study suggests that free flaps are not more expensive than other methods and may provide cost savings for selected patients.     

How to fashion a TRAM flap in the presence of a lower midline laparotomy scar. An experimental study in rats

The transverse rectus abdominis musculocutaneous (TRAM) flap cannot be used successfully in a patient with a pre-existing midline abdominal scar because the area distal to the scar undergoes circulatory failure leading to necrosis. To investigate the usefulness of various procedures to improve the circulation in such a flap, we studied the percentage area survival of experimental abdominal island flaps in five groups of rats with pre-existing midline scar treated by different procedures which depended on the source of blood used to supply the flap (control, arterial, venous, arteriovenous shunt, and delayed, n = 5 in each group). All flaps in the arterial group survived completely. The mean (SEM) percentages of the flaps that survived in the control (17(2)%) and venous (17(1)%) groups were significantly lower than those in the delayed (31(2)%) and arteriovenous shunt (67(6)%) groups (all, p < 0.01). These results indicate that preservation of arterial inflow by arterial anastomosis or arteriovenous shunt on the opposite side is important if the flap is to survive across the midline scar. Preservation of the vein in the opposite flap is not essential, because venous outflow is supposed to drain through the midline scar into the epigastric vein of the pedicle without any signs of congestion.     

The role of the venous system in the abdominal flap of the rat

The abdominal flap of the rat has become a popular model with investigators. Recently, researchers have been reporting survival of skin flaps with varying blood supplies. We studied the viability of skin flaps on a consistent model with varied blood supply. An 8 x 9 cm flap was raised in 40 male Sprague-Dawley rats. The viability of the flaps could be studied in 25 rats. The survival of a pedicled flap based on the left inferior epigastric artery and vein was compared with that of a pedicled flap with enhanced venous drainage. The survival of a venous flap based on the paired inferior epigastric veins and the paired long thoracic veins was compared with that of an arterialized venous flap. A composite graft was used as a control for all groups. A qualitatively improved survival was found in the pedicled venous-enhanced group (66 percent) compared with the pedicled flaps (56 percent) (p > 0.05). An improved survival was found in the arterialized venous flap (57 percent) compared with the venous flap (40 percent) (p < 0.05). All flaps had improved survival compared with the composite graft (0.6 percent) (p < 0.05).     

Appraising the ephemeral "alpha phenomenon": a reply to Hardt and Kamiya

1. The contribution of endogenously formed prostaglandins of the E series (PGE) to the development of reactive and functional hyperaemia was studied in the human forearm. 2. Forearm blood flow was recorded using venous occlusion plethysmography. The concentration of prostaglandin E-like substances (PLS) in the venous effluent from the muscle was analysed using bio-assay. For inhibition of PG biosynthesis, indomethacin (1-25 mg/kg body weight) was administered. 3. Following 5 min of arterial occlusion, a marked hyperaemia developed during the next 150 sec. Indomethacin, while not affecting the resting arterial blood flow, significantly decreased the peak level as well as the duration of the hyperaemia. The total reactive hyperaemia was 25 ml./100 ml. tissue before, and 13 ml./100 ml. tissue after administration of indomethacin. 4. During sustained isometric forearm contraction, and following isometric and dynamic forearm muscle activity, a moderate hyperaemia was observed. This was significantly diminished when indomethacin had been administered, although not to the same extent as the reactive hyperaemia. The total hyperaemia in the absence and presence of indomethacin was 113 and 77 ml./100 ml. tissue, respectively, in connexion with isometric contraction and 206 and 120 ml./100 ml. tissue, respectively, following dynamic work. 5. The venous concentration of PLS was very low at rest. A significantly increased concentration was observed after ischaemia. This increased release of PLS was entirely suppressed by indomethacin. With the present assay method, muscular activity elicited no detectable change in the venous concentration of PLS. 6. It is concluded that reactive hyperaemia depends to a considerable extent on an intact PGE synthesis. It is furthermore suggested that endogenous PGE may contribute to the functional hyperaemia that appears during and after muscle activity.     

Applications of the island trapezius myocutaneous flap in oral maxillofacial surgery]

The experience in immediate reconstruction of oral maxillofacial defects of 23 cases by island trapezius myocutaneous flaps from April 1985 to July 1993 is presented. The smallest flap was 6 x 4 cm and the largest 12 x 8 cm, with all the cases successful. The selection of the vascular pedicle of the myocutaneous flaps, the technique of the operation, the advantages and the disadvantages of the method are discussed.     

Effects of the number of pedicles on perfusion and survival of venous flaps: an experimental study in rabbits

Venous flaps are new tools for reconstructive surgery; however, the survival mechanisms of these flaps are not clearly known. This study compares the effects of the number of pedicles in venous flaps and studies the perfusion of these flaps. In the rabbit ear composite tissue venous flap model without the underlying bed and perivenous areolar tissue, three groups with a different number of pedicles were created. The groups consisted of single-pedicled, two-pedicled, and three-pedicled venous flaps. Radioactive tracer studies with technetium 99m were undertaken to assess inflow and drainage. The venous pressure in each pedicled vein and pressure gradients were also documented between the venous pedicles. All single-pedicled venous flaps became necrotic. The mean viable flap area was 40.5% for the two-pedicled venous flaps, 75.8% for the three-pedicled flaps, and 94.1% for the axial-pattern control flaps. Inflow and drainage of the radioactive substance in the three-pedicled venous flaps were better than the two-pedicled venous flaps, but the axial-pattern control flaps were superior to both. We conclude that although venous flaps are still not as reliable as conventional flaps, increasing the number of pedicles affected flap survival positively, and venous flap perfusion occurred due to pressure gradients between flap pedicles.     

Timing of pedicle thrombosis and flap loss after free-tissue transfer

A series of 990 consecutive free flaps was reviewed to determine how often pedicle thrombosis occurred, when it occurred, and if the timing of thrombosis detection had any relationship to the probability of flap salvage. The overall thrombosis rate was 5.1 percent, and the flap loss rate was 3.2 percent. The majority (80 percent) of thrombi occurred within the first 2 postoperative days. Only 5 thrombi (10 percent) were known to have occurred after the third postoperative day. No flaps that developed thrombosis after the third postoperative day were salvaged successfully. Had flap monitoring been discontinued after the first 3 postoperative days, our results in this series would have been unchanged. Thrombosis of the vein (54 percent) was more common than arterial thrombosis (20 percent) or thrombosis of both artery and vein (12 percent). Almost all purely arterial thrombi (90 percent) occurred before the end of the first postoperative day, whereas 41 percent of all venous thrombi occurred later. We conclude that arterial monitoring is most critical immediately after surgery. Beginning on the second postoperative day, venous monitoring becomes progressively more important to flap success. The cost-effectiveness of postoperative monitoring of free flaps is greatest during the first 2 days, after which it decreases significantly.     

Reform of the pedicled abdominal subcorium vascular-net flap and its clinical application

In order to resolve the shortcomings of traditional pedicled abdominal skin flap, the pedicled abdominal subcorium vascular-net flap was reformed and applied clinically. Twenty-eight cases with scar on hand or wrist were treated, including 20 males and 8 females. The age was ranged from 18 to 35 years old. The key point in the design was rotating 45 degrees of the flap from the primary site toward the pedicle. The ratio of the length to width of the flap was 1-1.8 : 1, and the wound of the donor site was covered by direct suture. Five to seven days later, all the flaps were divided and survived. The advantages of this flap were as follows: skin-grafting on the donor site was not necessary; the time needed for cutting the pedicle was shortened, and the flap is thinner than the traditional flap.     

Superiority of the microvascularly augmented flap: analysis of 50 transverse rectus abdominis myocutaneous flaps for breast reconstruction

Our experience with 50 transverse rectus abdominis myocutaneous (TRAM) flap transfers was evaluated as to the types of TRAM flaps, indications for breast reconstruction with a TRAM flap, and complications. The TRAM flap was transferred as a free flap in 7 patients, a unipedicled flap in 14 patients, and a microvascularly augmented flap in 29 patients. Microvascular augmentation was performed through the contralateral inferior epigastric vascular system to the superiorly pedicled muscle in 10 patients who had undergone radical mastectomy and the ipsilateral inferior epigastric vascular system in 19 patients who had undergone modified radical mastectomy. In this series, the incidence of flap-site complications, including total flap loss, partial flap loss, and fat necrosis, was lowest in the microvascularly augmented flap group. Particularly, incidence of partial flap loss in the microvascularly augmented flap group was significantly lower than in the unipedicled flap group (p < 0.01). These outcomes demonstrated the superiority of the microvascularly augmented TRAM flap for breast reconstruction.     

Internal mammary artery and vein supercharge in TRAM flap breast reconstruction

To improve the blood supply of the pedicled flap we have performed an additional microvascular augmentation to this type of breast reconstruction procedure since 1991. The ipsilateral deep inferior epigastric pedicle is anastomosed to the internal mammary artery and vein (IMAV supercharge). In 19 of 20 patients this technique proved to be feasible. For the venous anastomoses the 3M microvascular anastomosis system facilitated the procedure. In one patient the venous anastomosis failed due to the small calibre of two internal mammary veins. In a majority of the cases rapid improvement of flap perfusion could be observed as the direct result of the supercharging. The IMAV supercharged flap is quite comparable with the free flap as regards to the operative procedure. Disadvantages are a slightly more extensive dissection and less freedom in positioning the flap due to the presence of the superior muscular pedicle. The main advantage is that the supercharge procedure minimises the risk of total flap loss. Further technical improvement may be obtained by the use of a contralateral vascular pedicle dissected with muscle-sparing techniques.     

Cerebral oximetry: a useful monitor during carotid artery surgery

Cerebral oximetry was evaluated as a monitor of oxygenation during carotid endarterectomy in 22 patients. The oximeter was a reliable continuous monitor, identifying changes in cerebral oxygenation during episodes of hypotension and after arterial occlusion. Changes in oxygenation correlated well with the surgical assessment of backbleeding after arterial clamping, but less well with other methods which are used to make a decision on insertion of an arterial shunt. There was no correlation between internal carotid artery stump pressure and change in cerebral oxygenation after application of the arterial cross clamp. However, cerebral oxygenation correlated weakly with the change in middle cerebral artery velocity as measured by transcranial Doppler ultrasonography (r = 0.49, p < 0.02).     

Antibiotic resistance pattern of enterotoxigenic Escherichia coli isolated from infants and young adults in Israel

BACKGROUND: The usual methods of closure of major chest and abdominal wall defects have significant disadvantages. Skin grafts provide no structural support and result in incisional hernias. Synthetic mesh requires skin cover and is prone to infection and wound breakdown. The tensor fasciae latae (TFL) myocutaneous flap offers skin cover and a semi-rigid fascial layer. We document our unit's experience in pedicled and free TFL flaps. METHODS: The TFL flap closure of trunk defects was undertaken in 10 patients between August 1989 and April 1997. All cases were not amenable to primary closure and repair with synthetic mesh or skin grafts. RESULTS: The defect was satisfactorily repaired in all cases without subsequent herniation. The closure techniques using a pedicled TFL flap and a TFL flap for a free-tissue transfer are described. CONCLUSIONS: We conclude that the TFL flap is the method of choice for repairs of major truncal defects.     

Interleukin-18 (IFNgamma-inducing factor) induces IL-8 and IL-1beta via TNFalpha production from non-CD14+ human blood mononuclear cells

Over a 6-month period, 23 members of the International Microvascular Research Group participated in a prospective survey of their microvascular free-flap practice. Data were recorded with each case for 60 variables covering patient characteristics, surgical technique, pharmacologic treatment, and postoperative outcome. A total of 493 free flaps were reported with a representative demographic distribution for age, sex, indications for surgery, risk factors, flap type, surgical technique, and pharmacologic intervention. Mixed effects logistic regression modeling was used to determine predictors of flap failure and associated complications. The overall incidence of flap failure was 4.1 percent (20 of 493). Reconstruction of an irradiated recipient site and the use of a skin-grafted muscle flap were the only statistically significant predictors of flap failure, with increased odds of failure of 4.2 (p = 0.01) and 11.1 (p = 0.03), respectively. A postoperative thrombosis requiring re-exploration surgery occurred in 9.9 percent of the flaps. The incidence of this complication was significantly higher when the flap was transferred to a chronic wound and when vein grafts were needed, with increased odds of failure of 2.9 (p = 0.02) and 2.5 (p = 0.02), respectively. There was a lower incidence of postoperative thrombosis when rectus/transverse rectus abdominis muscle (TRAM) flaps were used, where odds of failure decreased by 0.36 (p = 0.04), and when subcutaneous heparin was administered in the postoperative period, where odds decreased by 0.27 (p = 0.04). There was an overall 69-percent salvage rate for flaps identified with a postoperative thrombosis. Intraoperative thrombosis occurred in 41 cases (8.3 percent) and was observed more frequently in myocutaneous flaps or when vein grafts were needed (5.5 and 5.0 greater odds, respectively; p < 0.001) but was not associated with higher flap failure (2 of 41 cases; 4.9-percent failure rate). The incidence of a hematoma and/or hemorrhage was increased in obese patients and when vein grafts were needed [2.7 (p = 0.02) and 2.6 (p = 0.03) greater odds, respectively], whereas this complication was significantly decreased in muscle flaps (myocutaneous or skin-grafted muscle), in tobacco users, when a heparinized solution was used for general wound irrigation, and when the attending surgeon performed the arterial anastomosis (in contrast to the resident or fellow on staff) (p < 0.05 for each factor). With the multivariable analysis, many factors were found not to have a significant effect on flap outcome, including the recipient site (e.g., head/neck, breast, lower limb, etc.); indications for surgery (trauma, cancer, etc.); flap transfer in extremes of age, smokers, or diabetics; arterial anastomosis with an end-to-end versus end-to-side technique; irrigation of the vessel without or with heparin added to the irrigation solution; and a wide spectrum of antithrombotic drug therapies. These results present a current baseline for free-flap surgery to which future advances and improvements in technique and practice may be compared.     

An ipsilateral superdrainaged transverse rectus abdominis myocutaneous flap for breast reconstruction

A conventional single pedicled TRAM (transverse rectus abdominis myocutaneous) flap is a musculocutaneous flap widely used for breast reconstruction. However, complications such as partial flap necrosis, fat necrosis, and fatty induration may occur as a result of unstable blood flow circulation to the flap. One major factor is venous congestion in the flap. In an effort to obtain more stable TRAM flap blood circulation, we anastomosed the ipsilateral deep inferior epigastric vein of a pedicled TRAM flap to the thoracodorsal vein. This procedure provides superdrainage by means of enhanced venous perfusion. This flap with superdrainage augmentation is referred to as a superdrainaged TRAM flap (12 patients). Changes in cutaneous blood flow were also assessed by measurement of cutaneous blood flow in zone IV using a laser blood flow meter (8 patients). The patients who underwent breast reconstructive surgery using this technique showed no evidence of postoperative complications such as flap necrosis, fat necrosis, or fatty induration. Satisfactory results were obtained during breast reconstruction in patients who had previously undergone a radical mastectomy with resultant large areas of tissue defects. In addition, the two patient groups, 12 patients with superdrainaged TRAM flap and 20 patients with single pedicled TRAM flap, were compared to assess differences in complications. The incidence of partial flap necrosis, fat necrosis, and fatty induration was lower among patients with superdrainaged flap than those with single pedicled flap.     

A reverse triangular soleus flap based on small distal communicating arterial branches

We report a 25-year-old woman who suffered traumatic damage to the medial malleolar area. Arteriography revealed a posterior tibial artery occlusion at the ankle. The predominant pattern of medial soleus vascularization was revealed during surgery. A reverse medial soleus flap including the posterior tibial pedicle was elevated. The lateral soleus was gradually elevated with it to ensure a full soleus base of the flap, resulting in a triangular shape. The flap survived completely. Both the triangular shape and the inclusion of the posterior tibial artery pedicle contributed the success of the flap by improving both the arterial supply and the venous drainage along the entire muscular flap.     

Interpretation of BOLD MRI signals in rat brain using simultaneously measured near-infrared spectrophotometric information

The purpose of this paper is to investigate the origin of the signal changes in the blood oxygenation level dependent effect (BOLD) and the influence of oxygen metabolism by utilizing near-infrared spectrophotometry (NIRS), which can measure deoxyhemoglobin (deoxyHb) content in blood vessels and redox states of cytochrome oxidase in whole tissue. Simultaneous MRI and NIRS measurements of the rat head were performed by changing oxygen concentrations in the inhalant gas. The signal intensity based on the BOLD effect depended on the influence of both arterial and venous blood deoxygenation in the brain, whose relative contributions differed at various points. In this paper, it is noteworthy that the differential apparent transverse relaxation rate between two conditions in the brain areas was linearly correlated with deoxyHb content determined by NIRS, except in severe hypoxia, and that no reduction of cytochrome oxidase occurred under the same conditions. These results indicate that the influence of hemodynamic changes on the signal intensity of the BOLD effect, and therefore functional MRI, can be elucidated by the NIRS information to determine actual changes of blood deoxygenation and blood volume.     

DNA variation in a 5-Mb region of the X chromosome and estimates of sex-specific/type-specific mutation rates

Owing to its unique anatomic arterial supply and dual nerve innervation, the first web space of the foot can be used to harvest various sizes and shapes of flaps, which the authors have classified into four types according to their usage in hand reconstruction. This in turn depends on the site, shape, and size of the soft-tissue defect in the hand. Web skin flaps (n = 8) were used in prevention of contracture in the first web space and for proximal finger reconstruction. Two-island skin flaps (n = 4) were used to resurface the pulp defect in two adjacent fingers. In severe adduction contracture of the first web space, fill-up web flaps (n = 10) were used to replace the volume defect after a release procedure in the hand. Adjuvant web flaps (n = 9) were used in wrap-around procedures, in dorsalis pedis flap transfer, and in vascularized joint transfer to supplement the main flaps and to restore sensation in the reconstructed area. In the past 10 years up to February of 1998, a total of 31 patients with soft-tissue defects in the hand and fingers were reconstructed using the web space free flap with flap survival rate of 100 percent. The mean static 2-point discrimination was 8.5 (7.2 to 10) mm, and the mean first web angle was 86 degrees. The advantage of the first web space flap from the foot is that it can easily be harvested to match various sizes and shapes of defects in the hand and fingers. In addition, because of the anatomic similarity in contour, thickness, texture, and nerve innervation with the hand, the sensory restoration is excellent with minimal morbidity at the donor site. By classifying the flaps into four types according to various sizes, shapes, and the site from which the flap are harvested, clinical usefulness in various types of hand and finger reconstruction was confirmed.     

Stimulation of angiogenesis to improve the viability of prefabricated flaps

The cutaneous area in a prefabricated myocutaneous flap surviving after elevation is dependent on the rate and amount of vascular ingrowth that occurs from the underlying muscle. Two modalities, basic fibroblast growth factor and hyperbaric oxygen, were used separately and together in a prefabricated myocutaneous flap animal model to improve flap survival. The semimembranous muscle, based on the saphenous vessels of 40 female Wistar rats weighing between 250 and 325 grams, was tunneled under the ipsilateral abdominal skin and sutured in place. A 3 x 5-cm silicone sheet was placed beneath the muscle flap, and the ipsilateral epigastric vessels were ligated. Four groups of 10 animals each received one of the following treatment regimes: a 1-ml normal saline infusion into the saphenous arterial pedicle, a 1-ml infusion of basic fibroblast growth factor (1.0 microg/gm of muscle), a 1-ml normal saline infusion and 14 hyperbaric oxygen treatments, or a 1-ml basic fibroblast growth factor infusion and 14 hyperbaric oxygen treatments. After 1 week, the muscle, still based on the saphenous vessels, was elevated with a 3 x 5-cm abdominal skin paddle. The flap was sutured back in place, leaving the silicone sheet intact. The surviving area of each flap was measured 1 week later after it had demarcated into viable and necrotic regions. Laser Doppler skin perfusion measurements were taken before and after flap elevation and before animal euthanasia. Sixteen flaps, 4 in each group, were examined histologically for vascularity by means of hematoxylin and eosin staining. There was a statistically significant increase in flap survival area when either basic fibroblast growth factor or hyperbaric oxygen was used alone. Further improvement was noted with combination therapy. Histology confirmed improved vascularity in the basic fibroblast growth factor and hyperbaric oxygen-treated flaps. This study shows a significant and reliable increase in the area of prefabricated myocutaneous flap survival using either basic fibroblast growth factor or hyperbaric oxygen. There is a further complementary effect when these two modalities are combined, leading to near complete flap survival through improved vascularity.     

Effects of sodium nitroprusside and phenylephrine on blood flow in free musculocutaneous flaps during general anesthesia

BACKGROUND: Hypoperfusion and necrosis in free flaps used to correct tissue defects remain important clinical problems. The authors studied the effects of two vasoactive drugs, sodium nitroprusside and phenylephrine, which are used frequently in anesthetic practice, on total blood flow and microcirculatory flow in free musculocutaneous flaps during general anesthesia. METHODS: In a porcine model (n = 9) in which clinical conditions for anesthesia and microvascular surgery were simulated, latissimus dorsi free flaps were transferred to the lower extremity. Total blood flow in the flaps was measured using ultrasound flowmetry and microcirculatory flow was measured using laser Doppler flowmetry. The effects of sodium nitroprusside and phenylephrine were studied during local infusion through the feeding artery of the flap and during systemic administration. RESULTS: Systemic sodium nitroprusside caused a 30% decrease in mean arterial pressure, but cardiac output did not change. The total flow in the flap decreased by 40% (P < 0.01), and microcirculatory flow decreased by 23% in the skin (P < 0.01) and by 30% in the muscle (P < 0.01) of the flap. Sodium nitroprusside infused locally into the flap artery increased the total flap flow by 20% (P < 0.01). Systemic phenylephrine caused a 30% increase in mean arterial pressure, whereas heart rate, cardiac output, and flap blood flow did not change. Local phenylephrine caused a 30% decrease (P < 0.01) in the total flap flow. CONCLUSIONS: Systemic phenylephrine in a dose increasing the systemic vascular resistance and arterial pressure by 30% appears to have no adverse effects on blood flow in free musculocutaneous flaps. Sodium nitroprusside, however, in a dose causing a 30% decrease in systemic vascular resistance and arterial pressure, causes a severe reduction in free flap blood flow despite maintaining cardiac output.