Increasing the COVID-19 immunization rate through allergy testing.

BACKGROUND: Vaccination of the population is required to combat the COVID-19 pandemic. Allergy testing could reduce anxiety towards COVID-19 vaccination and thereby may increase vaccination rate, however, its effectiveness remains unclear. METHODS: One hundred and thirty prospective real-life patients in need of but not daring to get vaccinated asked for allergy workup for COVID-19 vaccine hypersensitivity in 2021/2022. Characterization of patients, identification of anxieties, decrease of patient's anxiety levels, overall vaccination rate and adverse reactions after vaccination were assessed. RESULTS: Tested patients were characterized by being female (91.5%) and having a high rate of previous allergies (e.g. to food 55.4%, drugs 54.6%, or previous vaccinations 50%) and dermatological disease (29.2%) but not always had medical contraindications for COVID-19 vaccination. Sixty one patients (49.6%) were highly concerned (4-6, Likert scale 0-6) about vaccination and 47 (37.6%) expressed resolving thoughts about vaccinaion anaphylaxis (3-6, Likert scale 0-6). However only 35 patients (28.5%) were scared of getting COVID-19 within 2 months (4-6, Likert scale 0-6) and only 11 (9%) patients had high expectations of getting COVID-19 (4-6, Likert scale 0-6). Allergy testing significantly (p < 0.01 to p < 0.05 respectively) reduced the median anxiety of allergic symptoms following vaccination: dyspnoea (4.2-3.1), to faint (3.7-2.7), long-term consequences (3.6-2.2), pruritus (3.4-2.6), skin rash (3.3-2.6) and death (3.2-2.6). After allergy testing, most patients (108/122, 88.5%) let themselves be vaccinated within 60 days. Revaccinated patients with previous symptoms experienced a reduction of symptoms (p < 0.05) upon revaccination. CONCLUSIONS: Patients not daring to get vaccinated have more anxiety towards vaccination than to acquire COVID-19. For those, allergy testing excludes vaccine allergy, and is a tool to increase vaccination willingness and thereby helps to combat vaccination hesitancy.

How accurate are Omron X-HJ-304-E and Yamax SW-700/701 pedometers at different speeds and various inclinations?

AIM: The purpose of this study was to investigate step count and energy expenditure accuracy of the piezoelectric Omron (Walking Style X-HJ-304-E) and spring-levered Yamax (Digi-Walker-SW-700/701) pedometers at different speeds and various inclinations. METHODS: Thirty subjects (15 females, aged: 24 ± 3 years) completed eleven 5-min trials at different treadmill speeds and inclinations (3.24 km∙h⁻¹ [inclination: 0, 9, 20%], 4.68 km∙h⁻¹ [0, 9, 20%], 6.48 km∙h⁻¹ [0, 9%], 9 km∙h⁻¹ [0%], 10.8 km∙h⁻¹ [0%], 12.6 km∙h⁻¹ [0%]). During each trial, an investigator recorded actual steps with a hand tally counter. Actual energy expenditure was measured using a portable indirect calorimeter. RESULTS: The Omron pedometer revealed high step count accuracy for all speeds and inclinations when worn on the hip or a backpack (Mean % of actual steps: 99.6%; Range: 95.8-101.3%). The Yamax pedometer revealed high step count accuracy (Mean % of actual steps: 99.8%; Range: 96.2-103.3%) when worn on the left hip at 6.48-12.6 km∙h⁻¹ (0%), 4.68 km∙h⁻¹ (9%, 20%), 6.48 km∙h⁻¹ (9%) and on the right hip at 10.8 km∙h⁻¹ (0%) and 6.48 km∙h⁻¹ (9%). The accuracy of the Omron and Yamax determined energy expenditure was poor (57.9-59.7%) when compared to indirect calorimetry. CONCLUSION: The Omron pedometer provides accurate step counts when worn on the hip and backpack at all tested speeds and inclinations. We therefore suggest an accurate application of this device for walking, hiking and running at moderate speeds. Both pedometers underestimated energy expenditure.

Active vs. passive recovery during high-intensity training influences hormonal response.

The aim of the present study was to compare the effects of active (A) vs. passive (P) recovery during high-intensity interval training on the acute hormonal and metabolic response. Twelve triathletes/cyclists performed four 4 min intervals on a cycle ergometer, either with A- or P-recovery between each bout. Testosterone, hGH, cortisol, VEGF, HGF and MIF were determined pre, 0', 30', 60' and 180' after both interventions. Metabolic perturbations were characterized by lactate, blood gas and spirometric analysis. A-recovery caused significant increases in circulating levels of cortisol, testosterone, T/C ratio, hGH, VEGF and HGF. Transient higher levels were found for cortisol, testosterone, hGH, VEGF, HGF and MIF after A-recovery compared to P-recovery, despite no differences in metabolic perturbations. A-recovery was more demanding from an athlete's point of view. Based on the data of testosterone, hGH and the T/C-ratio, as well as on the data of VEGF and HGF it appears that this kind of exercise protocol with A-recovery phases between the intervals may promote anabolic processes and may lead to pro-angiogenic conditions more than with P-recovery. These data support the findings that also the long term effects of both recovery modes seem to differ, and that both can induce specific adaptations.

Acute metabolic, hormonal, and psychological responses to different endurance training protocols.

In the last years, mainly 2 high-intensity-training (HIT) protocols became common: first, a Wingate-based "all-out" protocol and second, a 4×4 min protocol. However, no direct comparison between these protocols exists, and also a comparison with high-volume-training (HVT) is missing. Therefore, the aim of the present study was to compare these 3 endurance training protocols on metabolic, hormonal, and psychological responses. Twelve subjects performed: 1) HVT [130 min at 55% peak power output (PPO)]; 2) 4×4 min at 95% PPO; 3) 4×30 s all-out. Human growth hormone (hGH), testosterone, and cortisol were determined before (pre) and 0', 30', 60', 180' after each intervention. Metabolic stimuli and perturbations were characterized by lactate, blood gas (pH, BE, HCO3⁻, pO2, PCO2), and spirometric analysis. Furthermore, changes of the person's perceived physical state were determined. The 4×30 s training caused the highest increases in cortisol and hGH, followed by 4 × 4 min and HVT. Testosterone levels were significantly increased by all 3 exercise protocols. Metabolic stress was highest during and after 4×30 s, followed by 4×4 min and HVT. The 4×30 s training was also the most demanding intervention from an athlete's point of view. In conclusion, the results suggest that 4×30 s and 4×4 min promote anabolic processes more than HVT, due to higher increases of hGH, testosterone, and the T/C ratio. It can be speculated that the acute hormonal increase and the metabolic perturbations might play a positive role in optimizing training adaptation and in eliciting health benefits as it has been shown by previous long term training studies using similar exercise protocols.

Plasma electrochemistry in ionic liquids: deposition of copper nanoparticles.

We report on the synthesis of copper nanoparticles in two different water- and air-stable ionic liquids using plasma electrochemical deposition. The copper nanoparticles were deposited in 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide ([Py(1,4)]Tf(2)N) and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([EMIm]Tf(2)N). To get information on the dimensions of the particles made, we have applied in situ transmission electron microscopy (TEM) (particles in ionic liquid). The chemical composition was investigated by ex situ X-ray photoelectron spectroscopy (XPS). We found that the copper particles produced in [Py(1,4)]Tf(2)N were larger in size compared to the particles obtained in [EMIm] Tf(2)N (roughly 20 vs. 10 nm). The chemical composition of the particle surface differs too. In both cases the particles are partly oxidised leading to a CuO shell, but the particles obtained in [Py(1,4)]Tf(2)N carry a lot of residues from the ionic liquid.

Efficacy of RS-61443 in reversing acute rejection in a rat model of hindlimb allotransplantation.

The requirement for effective, minimally toxic immunosuppression remains a major obstacle to performing human composite tissue allotransplantation. The skin component of composite tissue (e.g., limb) allografts is especially antigenic, necessitating toxic immunosuppressant doses to prevent or reverse acute rejection. In previous experiments, RS-61443, an experimental mycophenolic acid ester that inhibits lymphocyte proliferation with minimal toxicity, prevented acute limb allograft rejection in rats for more than 8 months when started on the day of transplantation. In this study, the ability of RS-61443 to reverse established acute rejection was tested in a rat model of hindlimb allotransplantation. Brown-Norway donors and Fischer 344 recipients provided a MHC mismatch for orthotopic midfemur limb transplants that were performed with microsurgical repair of femoral vessels and sciatic nerve. Three groups were studied: untreated allografts (n = 6); allografts receiving RS-61443 at 30 mg/kg/day, started on postoperative day 7 (n = 11); and allografts receiving RS-61443 at 30 mg/kg/day, started on postoperative day 9 (n = 9). Skin and soft tissues were biopsied periodically to assess rejection. Untreated allografts had complete acute rejection within 12-13 days. Animals in both the 7- and 9-day groups developed moderate to severe rejection clinically and histologically before initiation of immunosuppressive therapy. In both groups, RS-61443 was able to reverse rejection completely in all animals from which biopsies were obtained at the time of death at 9-16 weeks after transplantation (P < 0.007). RS-61443 was highly effective as a primary immunosuppressant for reversing established acute rejection in rat hindlimb allografts.

A long-term study of allogeneic rat hindlimb transplants immunosuppressed with RS-61443.

Although technically possible, limb allotransplantation has not been applied clinically. The skin component is especially antigenic, requiring high immunosuppressant doses with an unacceptable toxicity profile. RS-61443, an experimental mycophenolic acid ester that inhibits lymphocyte proliferation without major systemic toxicity, was tested as an immunosuppressant to prevent rejection of rat hindlimb allotransplants. Utilizing Brown-Norway donors and F344 recipients to provide a major mismatch at the MHC, midfemur orthotopic limb transfer was performed with microsurgical repair of femoral vessels and sciatic nerve. Four primary groups were studied: autografts (n = 4); untreated allografts (n = 6); allografts receiving CsA 10 mg/kg for 20 days, then twice per week (n = 6); and allografts receiving RS-61443 30 mg/kg/day (n = 6). Skin and soft tissues were biopsied to assess rejection. Autografts had indefinite limb survival, while untreated allografts had complete acute rejection within 10-12 days. Five of the six CsA rats developed delayed mild-moderate acute rejection within 6 months. In contrast, 5 of the 6 RS-61443 rats had no rejection after at least 32 weeks, while the sixth rat developed only slight rejection on skin biopsy. All animals regained full sensation and partial functional return. RS-61443 is highly effective as a primary immunosuppressant for hindlimb allotransplantation. The disturbing moderate rejection observed in CsA animals, which was absent with RS-61443, may significantly hamper function of transplanted limbs.

Use of combination of low-dose cyclosporine and RS-61443 in a rat hindlimb model of composite tissue allotransplantation.

Despite technical feasibility, composite tissue allotransplantation has not been applied clinically because of immunosuppressive toxicity associated with these highly antigenic allografts. Combination immunosuppression therapy can help overcome this obstacle by allowing lower doses of individual drugs and minimizing toxicity. RS-61443 (mycophenolate mofetil), an effective immunosuppressant that inhibits lymphocyte proliferation, was tested at subtherapeutic doses in combination with cyclosporine (CsA) in a rat hindlimb allotransplantation model with a major antigenic mismatch at the MHC. Five groups were studied: untreated autograft controls (n=4), untreated allograft controls (n=6), allografts receiving low-dose CsA 1.5 mg/kg/day (n=11), allografts receiving low-dose RS-61443 15 mg/kg/day (n=17), and allografts receiving combination low-dose CsA 1.5 mg/kg/day + RS-61443 15 mg/kg/day (n=18). The autograft controls survived indefinitely, while untreated allograft control animals developed severe rejection within 12 days. Subtherapeutic CsA and RS-61443 monotherapy groups developed acute rejection in 64% and 100% of rats, respectively. In contrast, only 11% of rats receiving combination therapy with CsA + RS-61443 at these same subtherapeutic doses developed acute rejection (P < or = 0.0013). Bone marrow toxicity, manifested primarily by anemia and measured objectively by hematocrits, was reduced significantly (P=0.04) in animals receiving low-dose RS-61443 therapy when compared with high-dose controls. These results confirm that subtherapeutic RS-61443 + CsA combination therapy is efficacious in preventing rejection while minimizing toxicity.

Mixed allogeneic chimerism as a reliable model for composite tissue allograft tolerance induction across major and minor histocompatibility barriers.

BACKGROUND: Although prolonged composite tissue allograft (CTA) survival is achievable in animals using immunosuppressive drugs, long-term immunosuppression of CTAs in the clinical setting may be unacceptable for most patients. The purpose of this study was to develop a model for reliable CTA tolerance induction in the adult rat across a major MHC mismatch without the need for long-term immunosuppression. METHODS: Mixed allogeneic chimeras were prepared by using rat strains with strong MHC incompatibility [WF (RT1Au), ACI (RT1Aa)] WF + ACI-->WF, n=23. The bone marrow (BM) of recipient animals was pretreated with low-dose irradiation (500-700 cGy), followed by reconstitution with a mixture of T cell-depleted syngeneic (WF) and allogeneic (ACI) cells. Additionally, the recipient animals received a single dose of anti-lymphocyte serum (10 mg) 5 days before bone marrow transplantation (BMT) and tacrolimus (1 mg/kg/day) from the day before BMT to 10 days post-BMT. Hindlimb transplants were performed 12 months after BMT. Five animals received a limb allograft irradiated (1000 cGy) just before transplantation. Rat chimeras were characterized (percentage of donor cells present within the bloodstream) by flow cytometry at 3 and 12 months after BM reconstitution and after hindlimb transplantation. RESULTS: Peripheral blood lymphocyte chimerism (WF/ACI) remained stable >12 months after BM reconstitution in 18/23 animals. Multi-lineage chimerism of both lymphoid and myeloid lineages was present, suggesting that engraftment of the pluripotent rat stem cell had occurred. In animals with donor chimerism >60% (n=18) no sign of limb rejection was present for the duration of the study. All animals with chimerism <20% (n=5) developed moderate signs of rejection clinically and histologically. Gross motor and sensory reinnervation (weight bearing, toe spread) developed at >60 days in 14/21 rats. Postoperative flow cytometry studies demonstrated stable chimerism in all animals studied (n=10). Five out of five animals with irradiated limb transplants showed no sign of GVHD at >100 days. CONCLUSIONS: Stable mixed allogeneic chimerism can be achieved in a rat hindlimb model of composite tissue allotransplantation. Hindlimb allografts to mixed allogeneic chimeras exhibit prolonged, rejection-free survival. Partial functional return should be expected. The BM transplanted as part of the hindlimb allograft plays a role in the etiology of GVHD. Manipulating that BM before transplantation may influence the incidence of GVHD. This represents the first reliable rat hindlimb model demonstrating rejection-free CTA survival in an adult animal across a major MHC mismatch without the long-term need for immunosuppressive agents.

The dynamic properties of tissue oxygen in healing flaps.

Oxygen delivery to random pattern and musculocutaneous flaps was investigated in a canine model. Oxygen tension was measured in the proximal and distal portions of each flap and in adjacent normal skin by means of a recently developed technique. The effect of delay techniques on tissue oxygen tension was also examined with modifications of the same flap model. All measurements were made over a range of inspired oxygen concentrations (21% to 100%) both before operation and at intervals up to 15 days after operation. Tissue oxygen tensions were significantly higher in the musculocutaneous flaps than in random pattern flaps up to 6 days after operation. They were higher in the proximal portions than in the distal portions in each flap type. This difference was greater in the random pattern flap. Delay techniques prevented the early dramatic decrease in postoperative oxygen tension seen in random pattern flaps. Differences in the pattern of oxygen delivery to random pattern and musculocutaneous flaps may in part explain the greater reliability of musculocutaneous flaps when transposed in the presence of infection.

The recalcitrant perineal wound after rectal extirpation. Applications of muscle flap closure.

Perineal wounds developing after abdominoperineal resection result in chronic purulent drainage and intermittent episodes of sepsis and are generally unresponsive to conservative medical and surgical treatment. Thirteen consecutive patients (aged 27 to 74 years; mean, 48 years) who underwent débridement and immediate muscle flap closure of these wounds were analyzed to identify risk factors for delayed healing and to evaluate the effectiveness of muscle flap coverage. Three risk factors were identified: preoperative or postoperative radiation therapy, resection for recurrent carcinoma, and inflammatory bowel disease. A total of 19 muscle flaps (11 gracilis, five gluteal thigh, two gluteus maximus, and one rectus abdominis) were used to close these wounds. During an average 3.5-year follow-up, four (31%) minor complications and one (8%) recurrence were noted to occur. Muscle flaps provide safe, effective, single-stage procedures for the closure of chronic perineal wounds.

Biologic priming of neutrophils in subcutaneous wounds.

Migration of neutrophils from blood into tissue is a complex response by circulating cells to chemotactic stimulation. Previous studies of the functional changes induced by this process have produced variable results. We compared neutrophils isolated from blood and from subcutaneous wounds in rabbits using established assays for adherence, chemotaxis, superoxide anion production, and hydrogen peroxide production. No differences in adherence to biologic surfaces or chemotaxis toward activated plasma were found. However, our results confirm the observation that wound neutrophils are "primed" for increased production of oxygen radicals. Primed responses were observed for both soluble (formyl methionyl leucylphenylalanine, phorbol myristate acetate) and particulate (opsonized zymosan) stimulants. Priming was also observed for peritoneal exudate neutrophils. The data suggest that the process of extravascular migration includes priming of the superoxide generating system.

Flap selection as a determinant of success in pressure sore coverage.

OBJECTIVE: To establish a treatment algorithm for the long-term surgical management of pressure sores. DESIGN: Retrospective case series. SETTING: University-based teaching hospital. PATIENTS: From March 1979 to July 1995, 280 unselected pressure sore reconstructions (113 ischial, 94 sacral, and 73 trochanteric sores) were performed in 201 patients (130 men and 71 women; age range, 16-90 years; mean, 50 years). Of the patients, 90% had severe spinal cord injuries (paraplegia or quadriplegia). Forty-one percent of the wounds were chronic (present longer than 3 months). MAIN OUTCOME MEASURES: Length of stay, postoperative morbidity and mortality, and flap success (defined as a completely healed wound). RESULTS: Overall, 89% of the flaps healed primarily (ischium, 83% [94/113]; sacrum, 91% [86/94]; trochanter, 93% [68/73]). Three fourths of cases were treated in a single stage (debridement and reconstruction). The inferior gluteus maximus island flap (ischium) (94% [32/ 34]), the V-Y gluteus maximus advancement flap (sacrum) (97% [36/37]), and the tensor fascia lata flap (trochanter) (95% [42/44]) had the highest success rates. Flap success was not significantly affected by the size of the pressure sore or the number of previous flaps used. Postoperative hospital stays averaged 20 days. The overall complication rate was 28%, most commonly from a slight wound edge dehiscence. CONCLUSIONS: Flap selection and the appropriate short- and long-term sequence of flap use significantly improve success rates for pressure sore coverage. Reconstruction can be reliably performed in a single stage with a relatively short hospitalization.

An adverse wound environment activates leukocytes prematurely.

This study was designed to evaluate the effect of different wound environments on wound activation. Our wound model provided two distinct environments, a well vascularized musculocutaneous flap and a poorly perfused random-pattern flap, in miniature swine. Leukocytes were isolated and analyzed by the following three variables: surface and total cellular Mac-1 (CD11b/CD18), superoxide anion expression, and lactoferrin release. Leukocytes from the unfavorable, poorly oxygenated wound environment activate on entry into the wound. Leukocytes from the musculocutaneous flap wound are better able to respond to a maximal challenge with the phorbol ester, phorbol myristate acetate. These findings may account for the enhanced bactericidal actions of the musculocutaneous flap compared with the random-pattern flap observed clinically.

Superoxide production by wound neutrophils. Evidence for increased activity of the NADPH oxidase.

Oxygen radical secretion by neutrophils is potentiated or "primed" by extravascular migration into wounds. To define this change in responsiveness more precisely we measured superoxide production by blood and wound neutrophils from rabbits using formylmethionyl-leucyl-phenylalanine and phorbol myristate acetate as agonists. In all experiments, the time- and dose-dependency of superoxide secretion were the same for blood and wound neutrophils. However, wound neutrophils produced significantly more superoxide. Furthermore, the cytochrome b component of the NADPH oxidase was found in greater quantities within wound neutrophils. We conclude that priming does little to alter the requirements for activating the NADPH oxidase but does significantly increase the velocity of superoxide generation. The data suggest that alterations in the assembly and function of the NADPH oxidase may contribute to enhanced superoxide secretion by wound neutrophils.

Microsurgical reconstruction of the midface.

OBJECTIVE: To establish a treatment algorithm for reconstructing complex midfacial defects. DESIGN: Retrospective case series. SETTING: University-based teaching hospital. PATIENTS: Thirty-one consecutive patients were treated from 1991 through 1995. The 18 males and 13 females were aged 15 to 90 years (mean age, 58 years). The cause of the defect included neoplasm (n = 27) and trauma (n = 4). Reconstruction consisted of 1 of 4 free flaps: rectus abdominis, radial forearm, fibula, or latissimus dorsi. Aesthetic and functional results were determined by patient questionnaires and physical examinations. MAIN OUTCOME MEASURES: Length of stay, postoperative morbidity and mortality, degree of aesthetic and functional restoration, and detection of tumor recurrence. RESULTS: Twenty-seven (87%) of the 31 patients underwent reconstruction with a single major procedure. All of the flaps survived. Postoperative hospital stays averaged 14 days. Late tumor recurrence occurred in 7 (23%) of the 31 patients and was promptly detected. Aesthetic and functional results were rated good or excellent in 77% (24/31) and 87% (27/31) of patients, respectively. Of the 20 patients who underwent alveolar ridge resection, 16 (80%) received dental rehabilitation, 44% of whom received osseointegrated implants into either a bone flap or remaining native bone. Osseointegrated implants were inset during the initial reconstruction 57% (4/7 patients) of the time. CONCLUSIONS: For complex midfacial defects, free-flap transfer can be performed with a high degree of success, restoring both appearance and function in most patients. The only instance in which bone is necessary to reconstruct the midface involves those areas in which osseointegrated implants are needed, ie, alveolar ridge (dental implant) and/or orbit (ocular prosthesis). In such cases, the fibula osteocutaneous free flap is the flap of choice. Otherwise, soft-tissue flaps are selected based on wound size.

Reconstruction of posterior neck and skull with vertical trapezius musculocutaneous flap.

The vertical trapezius musculocutaneous flap has been successfully utilized for reconstruction in 13 patients with complex posterior skull and neck defects. This flap based on its vascular pedicle, the descending branch of the transverse cervical artery, provides well-vascularized tissue for coverage of defects related to chronic osteomyelitis, tumor extirpation, osteoradionecrosis, and dehisced cervical laminectomy wounds. Emphasis on flap design, including the location of the skin island, allows adequate wound coverage, direct donor site closure, and muscle function preservation. With its large size and wide arc of rotation, the vertical trapezius musculocutaneous flap provides reliable coverage for posterior trunk, cervical, and skull defects.

Platysma musculocutaneous flap: clinical and anatomic considerations in head and neck reconstruction.

The platysma musculocutaneous flap was used in 14 patients for reconstruction of the oral lining and external skin coverage in the head and neck area. Complications occurred in five patients. Only one patient, however, required further surgery and this was for correction of a poor cosmetic result. The skin and subjacent muscle are supplied by a major vascular pedicle from the facial artery and vein and a minor pedicle from the transverse cervical artery and vein. Either pedicle can be used as the pivot for the flap's arc of rotation. The donor defect can be closed primarily and did not present any problems. The flap can be raised with both its motor and sensory supply intact. The thinness and pliability, color match, and proximity make this flap a useful adjunct in head and neck surgery.

Influence of radiotherapy on microvascular reconstruction in the head and neck region.

Over a 5-year period at the University of California San Francisco, 42 patients who required microvascular reconstruction for abnormalities in the head and neck area were identified. Twenty-four patients (Group I) underwent reconstruction for a variety of neoplastic and non-neoplastic conditions and did not receive radiotherapy. Eighteen patients (Group II) had undergone previous radiotherapy averaging 6,090 rads. The mean ages for Group I and II patients were 40.7 and 55.5 years, respectively. In Group I, 13 muscle, 7 fasciocutaneous, 4 osteocutaneous, and 2 jejunal transfers were performed. In Group II, 11 muscle, 5 fasciocutaneous, 3 osteocutaneous, and 2 jejunal transfers were performed. Flap survival at 3 months was 88% in Group I and 95% in Group II. Wound complication rates were similar in both groups (15% Group I, 19% Group II), as was donor site morbidity (15% Group I, 29% Group II). Operative times (10.9 hours Group I, 10.6 hours Group II) and median postoperative hospitalization (14 days Group I, 16 days Group II) were comparable as well. Four of the five patients in whom the flap procedures failed were subsequently treated by a second microvascular reconstruction. Previous irradiation of the recipient bed did not appear to affect the success of subsequent microvascular reconstruction or the difficulty of such reconstruction as judged by operative time.