Qun-Ying Hu

Free flap reexploration: Indications, treatment, and outcomes in 1193 free flaps

Background: Microvascular free tissue transfer is a reliable method for reconstruction of complex surgical defects. However, there is still a small risk of flap compromise necessitating urgent reexploration. A comprehensive study examining the causes and methods of avoiding or treating these complications has not been performed. The purpose of this study was to review the authors’ experience with a large number of microvascular complications over an 11-year period. Methods: This was a retrospective review of all free flaps performed from 1991 to 2002 at Memorial Sloan-Kettering Cancer Center. All patients who required emergent reexploration were identified, and the incidence of vascular complications and methods used for their management were analyzed. Results: A total of 1193 free flaps were performed during the study period, of which 6 percent required emergent reexploration. The most common causes for reexploration were pedicle thrombosis (53 percent) and hematoma/bleeding (30 percent). The overall flap survival rate was 98.8 percent. Venous thrombosis was more common than arterial thrombosis (74 versus 26 percent) and had a higher salvage rate (71 versus 40 percent). Salvaged free flaps were reexplored more quickly than failed flaps (4 versus 9 hours after detection; p = 0.01). There was no significant difference in salvage rate in flaps requiring secondary vein grafting or thrombolysis as compared with those with anastomotic revision only. Conclusions: Microvascular free tissue transfer is a reliable reconstructive technique with low failure rates. Careful monitoring and urgent reexploration are critical for salvage of compromised flaps. The majority of venous thromboses can be salvaged. Arterial thromboses can be more problematic. An algorithm for flap exploration and salvage is presented.

a Review of 716 Consecutive Free Flaps for Oncologic Surgical Defects: Refinement in Donor-site Selection and Technique

&NA; Free‐tissue transfer has become an important method for reconstructing complex oncologic surgical defects. This study is a retrospective review of a 10‐year experience with 716 consecutive free flaps in 698 patients. Regional applications included the head and neck (69 percent), trunk and breast (14 percent), lower extremity (12 percent), and upper extremity (5 percent). Donor sites included the rectus abdominis (195), fibula (193), forearm (133), latissimus dorsi (69), jejunum (55), gluteus (28), scapula (26), and seven others (17). Microvascular anastomoses were performed to large‐caliber recipient vessels using a continuous suture technique; end‐to‐end anastomoses were preferred (75 percent). Flaps were designed to avoid the need for vein grafts. Conventional postoperative flap monitoring methods were used. These included clinical observation supplemented by Doppler ultrasonography, surface temperature probes, and pin prick testing. Buried flaps were either evaluated with Doppler ultrasonography or not monitored. The overall success rate for free‐flap reconstruction of oncologic surgical defects was 98 percent. Fifty‐seven flaps (8 percent) were reexplored for either anastomotic or infectious problems. Reexplored flaps were salvaged in 40 cases (70 percent). Surviving flaps resulted in a healed wound and did not delay postoperative radiation or chemotherapy. The incidence of major and minor postoperative complications was 34 percent. The mean duration of hospitalization was 20 days, and the average cost was

Reconstruction of complex oncologic chest wall defects: a 10-year experience.

40,224. The results of this study support the need for only seven donor sites to solve the majority (98 percent) of oncologic problems requiring microsurgical expertise. The evolution of preferred donor sites for specific regional applications is illustrated in this 10‐year experience. Technical refinements have simplified performing the microsurgical anastomoses and essentially eliminated the need for vein grafts. Conventional monitoring has led to the rapid identification of vascular compromise and subsequent flap salvage in the majority of non‐buried free flaps. (Plast. Reconstr. Surg. 102: 722, 1998.)

Reconstruction of extremity long bone defects after sarcoma resection with vascularized fibula flaps: a 10-year review.

The repair of complex chest wall defects presents a challenging problem for the reconstructive surgeon. Although the majority of such defects could be repaired with the use of local and regional musculocutaneous flaps, more complicated cases require increasingly sophisticated reconstructive techniques. This study reviews the experience at a single cancer center with chest wall reconstruction over a decade. A retrospective review was undertaken for each patient who underwent chest wall reconstruction from 1992 to 2002. Patient demographics and variables, including pathologic diagnosis, extent of resection, size of defect, method of reconstruction, and outcome were evaluated. There was a total of 113 patients, 88 females and 25 males. The average age was 58 years (range, 19–88 years). The most common diagnoses were breast cancer and sarcoma. The average area of the chest wall defect after resection was 266 cm2. One hundred fifty-seven musculocutaneous or muscle flaps were performed for reconstruction of the chest wall. Eleven percent of patients underwent reconstruction with autologous free tissue transfer. One hundred six patients underwent a single operation. Seven patients required a second operation for salvage of a complication. In 19 cases (15%), more than 1 flap was used simultaneously to complete the reconstruction. Eighty-four percent of the patients achieved stable chest wall reconstruction with no complications. Seven patients (4%) had partial (>10%) flap loss. The most common remaining postoperative complications were delayed wound healing (3% of patients), infection (2.5%), and hematoma (2.5%). Immediate chest wall reconstruction is safe, reliable, and can most often be accomplished with 1 operation. A variety of flaps, both single and in combination, could be used to achieve definitive coverage of the chest wall after extirpative surgery. The reconstructive choice is dependent on factors such as size of the defect, location on the chest wall, arc of rotation of the flap, and availability of recipient vessels. Based on this single institutional experience over a decade, an algorithm to chest wall reconstruction is provided.

What Is the Optimum Timing of Postmastectomy Radiotherapy in Two-Stage Prosthetic Reconstruction: Radiation to the Tissue Expander or Permanent Implant?

Background: Limb-sparing wide excision has become as effective as amputation in treating extremity sarcoma. Limb reconstruction has traditionally involved allografting. The authors evaluated reconstruction of extremity long bone defects after tumor resection using fibula free flaps. Methods: A retrospective chart review (1991 to 2002) was performed of 25 consecutive patients at Memorial Sloan-Kettering Cancer Center who underwent reconstruction with free fibula flaps after limb-sparing resection of extremity sarcomas. Timing of reconstruction, complications, metastasis, survival, bone union, and functional outcome were analyzed. Functional assessment was based on the 1987 Musculoskeletal Tumor Society Score/Enneking classification. Results: Twenty-five patients (14 male patients and 11 female patients) were treated. Osteosarcoma (n = 8), Ewing’s sarcoma (n = 8), and chondrosarcoma (n = 6) accounted for the majority of the cases. Reconstructed areas included tibia (n = 9), radius (n = 5), humerus (n = 6), femur (n = 4), and ulna (n = 1). All flaps survived (100 percent). One patient required emergent reexploration (4 percent), one suffered partial flap skin loss (4 percent), and three experienced postoperative infections (12 percent). In patients followed over 6 months, uncomplicated bony union was achieved in 11 of 14 patients (78 percent). After secondary procedures, bony union was ultimately achieved in 13 of 14 patients (93 percent), all of whom had good functional outcomes. Eight patients suffered local recurrences or metastases (32 percent); six died during the study period. Conclusions: The microvascular free fibula flap has a lower infection rate than traditional allograft reconstruction. There is a high rate of bone union, and functional outcome is good. Thus, the authors recommend the microvascular fibula transfer as the technique of choice for reconstructing large, complex long bone defects resulting from tumor extirpation.

the Protective Effect of L-arginine on Ischemia-reperfusion Injury in Rat Skin Flaps

Background: Postmastectomy radiotherapy is increasingly common for patients with advanced breast cancer. The optimal timing and sequence of mastectomy, reconstruction, and radiotherapy remains unresolved for patients choosing immediate two-stage prosthetic reconstruction. Methods: Long-term outcomes were compared for all patients with prosthetic-based reconstruction without radiation, radiation to the tissue expander, or to the permanent implant from 2003 to 2012 performed by the senior author (P.G.C.). Surgeon-evaluated outcomes included reconstructive failure, aesthetic results, and capsular contracture. Odds of failure with radiotherapy at different times were evaluated with logistic regression and Kaplan-Meier analysis. Patient-reported outcomes were assessed using the BREAST-Q. Results: A total of 1486 reconstructions without radiation, 94 reconstructions with tissue expander radiation, and 210 reconstructions with permanent implant radiation were included. Six-year predicted failure rates were greater for patients with tissue expander radiation than for patients with permanent implant radiation (32 percent versus 16.4 percent; p < 0.01). Patients undergoing radiation to the tissue expander had a greater proportion of very good to excellent aesthetic results compared to patients with permanent implant radiation (75.0 percent versus 67.6 percent; p < 0.01) and lower rates of grade IV capsular contracture (p < 0.01). BREAST-Q scores were similar for patients with the different radiation timings. Conclusions: Although the risk of reconstructive failure is significantly higher for patients with tissue expander radiation compared to patients with permanent implant radiation, the aesthetic results and capsular contracture rates are slightly better. Patient reported outcomes do not differ between patients with tissue expander or permanent implant radiation. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

Use of a nitric oxide precursor to protect pig myocutaneous flaps from ischemia-reperfusion injury.

&NA; The objective of this study was to examine whether the administration of L‐arginine, a precursor of nitric oxide and substrate of nitric oxide synthase, prior to reperfusion could lead to decrease in neutrophil‐mediated tissue injury and improved flap survival. Epigastric island skin flaps were elevated in 70 rats and rendered ischemic. Thirty minutes prior to reperfusion, the rats were treated with intraperitoneal saline (n = 15), L‐arginine (n = 15), Darginine (n = 15), or N&ohgr;‐nitro‐L‐arginine methylester plus L‐arginine in equimolar amounts (n = 15). Flap survival at 7 days and neutrophil counts at 24 hours were evaluated. Flap necrosis as expected in the sham group of animals (n = 10) was 0.0 percent, while the control (saline‐treated) animals had 59.6 percent necrosis. Animals treated with L‐arginine demonstrated a significant decrease in flap necrosis to 12.7 percent. This protective effect was almost completely negated by N&dgr;‐nitro‐L‐arginine methylester, which significantly increased flap necrosis to 49.3 percent and was much less pronounced with D‐arginine (28.6 percent). Neutrophil counts were significantly decreased in flaps from L‐arginine‐treated and sham animals versus both saline and N&ohgr;‐nitro‐L‐arginine methylester—treated groups. We conclude that administration of L‐arginine prior to reperfusion can significantly reduce the extent of flap necrosis and flap neutrophil counts due to ischemiareperfusion injury. This protective effect is completely negated by nitric oxide synthase inhibition. Since L‐arginine reduces the number of neutrophils within the flap and the extent of flap necrosis only in the presence of active nitric oxide synthase, we hypothesize that this protective effect of L‐arginine on ischemia‐reperfusion injury is secondary to a nitric oxide‐mediated suppression of neutrophil‐mediated injury. (Plast. Reconstr. Surg. 100: 1227, 1997.)

The timing and nature of neovascularization of jejunal free flaps : An experimental study in a large animal model

&NA; Nitric oxide is a radical with vasodilating properties that protects tissues from neutrophil‐mediated ischemiareperfusion injury in the heart and intestine. Previous studies in our laboratory suggested that L‐arginine, a nitric oxide precursor, can protect skin flaps from ischemiareperfusion injury. In this study, we examined the effects of l‐arginine on the survival of myocutaneous flaps in a large animal model and established whether this effect was mediated by nitric oxide and neutrophils. Two superiorly based 15 × 7.5 cm epigastric myocutaneous island flaps were dissected in 15 Yorkshire pigs weighing 45 to 50 kg. One of the flaps was subjected to 6 hours of arterial ischemia and then reperfused for 4 hours (ischemia‐reperfusion flaps), whereas the other flap was used as a non‐ischemic control (non‐ischemia‐reperfusion flaps). The flaps were divided into four groups: control non‐ischemia‐reperfusion flaps that received only saline (group I); ischemia‐reperfusion flaps that were treated with saline (group II); and flaps treated with either larginine (group III) or NSymbol‐nitro‐l‐arginine methylester (L‐NAME), a nitric oxide synthase competitive inhibitor, plus l‐arginine in equimolar amounts (group IV). These drugs were administered as an intravenous bolus 10 minutes before the onset of reperfusion, followed by a 1‐hour continuous intravenous infusion. Full‐thickness muscle biopsies were taken at baseline, 3 and 6 hours of ischemia, and 1 and 4 hours of reperfusion. The biopsies were evaluated by counting neutrophils and measuring myeloperoxidase activity. At the end of the experiment, skeletal muscle necrosis was quantified using the nitroblue tetrazolium staining technique, and a full‐thickness biopsy of each flap was used for determination of water content. Statistical analysis was performed using analysis of variance and the Newman‐Keuls test. Symbol. No caption available. Non‐ischemia‐reperfusion flaps showed no muscle necrosis. Ischemia‐reperfusion flaps treated with saline had 68.7 ± 9.1 percent necrosis, which was reduced to 21.9 ± 13.6 percent with l‐arginine (p < 0.05). L‐NAME administered concomitantly with l‐arginine demonstrated a necrosis rate similar to that of saline‐treated ischemia‐reperfusion flaps (61.0 ± 17.6 percent). Neutrophil counts and myeloperoxidase activity after 4 hours of reperfusion were significantly higher in ischemia‐reperfusion flaps treated with L‐NAME and L‐arginine as compared with the other three groups (p < 0.05). Flap water content increased significantly in ischemia‐reperfusion flaps treated with saline and L‐NAME plus L‐arginine versus non‐ischemia‐reperfusion flaps (p < 0.02) and l‐argininetreated ischemia‐reperfusion flaps (p < 0.05). There was no difference in flap water content between ischemiareperfusion flaps treated with l‐arginine and non‐ischemia‐reperfusion flaps. Administration of l‐arginine before and during the initial hour of reperfusion significantly reduced the extent of flap necrosis, neutrophil accumulation, and edema due to ischemia‐reperfusion injury in a large animal model. This protective effect is completely negated by the use of the nitric oxide synthase blocker L‐NAME. The mechanism of action seems to be related to nitric oxide‐mediated suppression of ischemia‐reperfusion injury through neutrophil activity inhibition. (Plast. Reconstr. Surg. 102: 2040, 1998.)

Ultraviolet excitation fluorescence spectroscopy : a noninvasive method for the measurement of redox changes in ischemic myocutaneous flaps

The present study was designed (1) to determine whether a free jejunal transfer in a large animal model can develop collateral circulation that is adequate to maintain viability after division of the pedicle and (2) to determine the earliest time pedicle ligation is safe after transplantation. A 15-cm jejunal segment was transferred to the necks of 18 dogs weighing 25 to 35 kg. The bowel segment was inset longitudinally under the skin on one side of the neck, partially covered by the neck muscles, and the mesenteric vessels were anastomosed to recipient vessels in the neck. The proximal and distal bowel stomas were exteriorized through skin openings 12 cm apart and matured. The dogs were subjected to ligation of the vascular pedicle at different intervals: postoperative day 7 (group I, n = 3), day 14 (group II, n = 5), day 21 (group III, n = 5), and day 28 (group IV, n = 5). Blood perfusion was measured in the proximal and distal bowel stomas before pedicle division (control) and 24 hours later using hydrogen gas clearance and fluorescein dye. Bowel necrosis was analyzed using planimetry. The bowel was also stained with hematoxylin and eosin and factor VIII, and new blood vessels were counted. Mean values (+/- standard deviation) were compared with control values for each test and with normal values in the intact bowel using analysis of variance with Neumann-Keuls post-hoc test for multiple comparisons. No jejunal free flaps survived when the vascular pedicle was divided 1 week postoperatively. Bowel survival was 60 percent at 2 weeks, 83 percent at 3 weeks, and 100 percent at 4 weeks. Hydrogen gas clearance values (ml/min/100 g) were 49.6 +/- 8.7 in the mucosa of the intraabdominal jejunum and 37.9 +/- 9.4 in the jejunum that was transferred to the neck before division of the pedicle. Twenty-four hours after pedicle division, hydrogen gas clearance values were 2.8 +/- 6.4 in group I (p < 0.05), 22.4 +/- 12.4 in group II, 23.9 +/- 9.3 in group III, and 34.2 +/- 7.5 in group IV. FluoroScan readings in the transferred jejunum were 201 +/- 7.2 in the control group, 9.3 +/- 2.8 in group I (p < 0.05), 79.1 +/- 10.6 in group II, 66.2 +/- 7.3 in group III, and 164 +/- 11.9 in group IV. New vessel formation as identified by factor VIII staining correlated with increasing bowel perfusion and flap survival rate. Bowel neovascularization, perfusion, and survival increased progressively 1 week after transfer. Significant portions of the transferred bowel will neovascularize and survive as early as 2 weeks postoperatively. However, a minimum of 4 weeks before ligation of the pedicle is necessary to maximize flap perfusion and guarantee survival.

Reconstruction of extensive composite posterolateral mandibular defects using nonosseous free tissue transfer.

In this report, we discuss application of the noninvasive technology of ultraviolet fluorescence spectroscopy to the metabolic analysis of normal and compromised myocutaneous flaps. Acute changes in tissue redox states during ischemia and reperfusion were determined analysis of changes in the fluorescence spectrum of reduced nicotinomide adenine dinucleotide (NADH). Analysis of the system for NADH fluorescence showed good correlation between excitation spectra recorded at 450 nm from pure beta-NADH and those recorded from porcine rectus abdominis myocutaneous flaps. Sequential measurements of surface fluorescence were obtained from six flaps subjected to 6 hours of warm arterial ischemia and 4 hours of reperfusion. Results were compared with spectra obtained from six contralateral nonischemic control flaps. A significant mean increase in NADH fluorescence (49 percent; p < 0.05) was demonstrated within 30 minutes of vascular occlusion. Fluorescence intensity continued to increase throughout the ischemic period, reaching 320.5 percent of baseline values at 6 hours. Reperfusion resulted in the prompt return of fluorescence intensity to baseline levels. These results show that fluorescence spectroscopy of endogenous NADH is a sensitive and reliable indicator of vascular occlusion in experimental myocutaneous flaps.