David A. Mitchell

Identification of perioperative risk factor by laser-doppler spectroscopy after free flap perfusion in the head and neck: A prospective clinical study

The aim of this study was to evaluate perioperative flap perfusion using noninvasive monitoring with a laser‐Doppler flowmetry and spectrophotometry unit (O2C) and identify whether perioperative blood flow, velocity, hemoglobin level (Hb), and oxygen saturation (SO2) measured could be used as indicators of free flap success. Measurements of blood flow, velocity, Hb, and SO2 were performed in 196 microvascular flaps, which had been transferred into the oral cavity to reconstruct ablative defects after surgery for oral cancer. The values were calculated superficially on the skin surface and at a depth of 8 mm. The results showed that perioperative absolute values measured were not associated with an increased rate of microvascular revisions or free flap failure. Independent predictors of microvascular revisions at the first postoperative day were the development of a falling trend in superficial and deep blood flow, and velocity in comparison with baseline values of variables measured. On day 2, all superficial and deep values of Hb, flow, and velocity were independent prognostic factors (P < 0.01), demonstrated as a downward trend were associated with a need for revision. The superficial and deep values of SO2 (P = 0.59 and 0.43, respectively) were not associated with ultimate free flap failure. This is the first clinical study to demonstrate that during early free flap integration to the recipient site different parameters of perfusion and oxygenation play an important role at different points of time. Within the first two postoperative days, changes in these parameters can help influence the decision to revise microvascular anastomoses.

Autonomization of free flaps in the oral cavity: A prospective clinical study

Controversy exists over how long a free flap is dependent on its pedicle and if neovascularization is different between flap types, recipient sites, and irradiated and nonirradiated patients. An understanding of the timing of this process should optimize the safety of secondary procedures involving the flap. In a prospective clinical study, hemoglobin oxygenation and capillary flow were measured in 50 flaps (25 forearm flaps, 15 osteocutaneous fibula flaps, and 10 anterolateral thigh flaps) 4 and 12 weeks postoperatively. The flaps were located at the floor of the mouth, cheek, or tongue (n = 39) or at the hard or soft palate (n = 11). Measurements were carried out using the O2C monitoring system under temporary digital occlusion of the pedicle. After 4 weeks, 17 free flaps were found to be autonomized indicated by the O2C measurements comparing both values before and after digital compression of the vascular pedicle. After 12 weeks, 41 patients had completion of free flap autonomization, as indicated by the HbO2 and CF before and after pedicle compression. The location of free flap in the lower jaw (P < 0.0001 after 4 weeks, P = 0.013 after 12 weeks), fasciocutaneous radial forearm flaps after 4 weeks (P < 0.0001), and not irradiated recipient site after 4 weeks (P = 0.014) were found to be positive factors significantly influencing autonomization. In conclusion, free flap autonomization depends on several variables which should be considered before further surgery after free flap reconstruction as the transferred tissue can be still dependent on its pedicle.

Evaluation of the vessels of the lower leg before microsurgical fibular transfer. Part I: anatomical variations in the arteries of the lower leg

Perfusion of a fibular flap is based on the peroneal artery. To avoid ischaemia of the lower leg postoperatively after the artery has been sacrificed, adequate perfusion must be guaranteed preoperatively. Although common anatomical variations and pathological changes are well recognised, the best way to evaluate the vascular system preoperatively is controversial. Our aim was to identify anatomical vascular patterns that may jeopardise either the limb or the flap while the fibula is being harvested, and provide a few simple rules for the assessment of preoperative evaluation techniques. We dissected 128 lower legs preserved in formalin and evaluated them for the incidence of vascular anatomical variants. In addition we measured absolute and relative loss of volume. Volume loss from the peroneal artery was considerable, with a loss of 23%. On two occasions the peroneal artery mimicked the anterior tibial artery in its course to the dorsalis pedis artery at the dorsum of foot; four times the tibial artery arose directly from the peroneal artery; and five times only a rudimentary posterior tibial artery could be found. There are numerous vascular variants in the lower leg, some of which could put the flap or the limb at risk. We therefore think that preoperative evaluation of the vascular system is advisable.

The value of perioperative antibiotics on the success of oral free flap reconstructions.

The subject of the presented study was to monitor and compare problems and outcomes of reconstructive surgery with microvascular free flaps in the head and neck region between groups of patients treated with perioperative antibiotics and a group of patients without antibiotics. Patients requiring oral reconstructive surgery following cancer resections with microvascular free flaps were prospectively evaluated (2007–2012). Antibiotic therapy was started 30 min before the operation and administered for 10 days. Three hundred and fifty patients were included (208 male, 59.4%; 142 female, 40.6%; mean age 59.8 ± 13.2 years). 330 patients received perioperative antibiotics. Twenty patients (5.7%) who received no antibiotics for specific reasons served as the control group. Wound infections developed in 33 of 122 patients (27%) who received benzylpenicillin, 17 of 88 patients (19.3%) who received amoxicillin combined with sulbactam and 25 of 120 patients (20.8%) who received cefuroxime. Ten patients (50%) who did not receive antibiotics developed wound infections. Receiving no antibiotics or penicillin showed no benefit (P = 0.11). Those receiving cefuroxime showed significantly lower incidence of wound infections (P = 0.034; risk decreased by the factor 2.88). The use of amoxicillin combined with sulbactam showed the lowest rate of wound infections (P = 0.018; risk decreased by the factor 3.46). The use of amoxicillin combined with sulbactam appears to be the most appropriate prophylactic antibiotic followed by cefuroxime in oral microsurgical free flap reconstructions. These data may serve as a guide until a controlled multicenter prospective trial is performed comparing newer antibiotics against current standards.

Quality of life after different oncologic interventions in head and neck cancer patients.

Patient reported outcomes following head and neck cancer are of great importance, given the functional, psychological, and social impacts of the disease and its treatment. In addition, not only is the number of publications on health-related quality of life (HRQOL) increasing in a variety of specialties, but there is also a growing awareness of the potential role of HRQOL in practice. Therefore, we aimed to investigate the HRQOL of head and neck cancer patients following different oncologic interventions, using an internationally established test. In this cross-sectional study, we included three different groups of 32 patients each. Participants had histologically confirmed invasive oral squamous cell carcinoma (OSCC) in the anterior floor of the mouth. Group allocation was based on treatment modality, as follows: only surgery (group 1), operation and adjuvant radiotherapy (XRT) (group 2), and the additional presence of osteoradionecrosis (ORN) (group 3). All patients were questioned about their HRQOL, using the standardized University of Washington Quality of Life Questionnaire (UW-QOL). Surveys for groups 1 and 2 were conducted at least 24 months after the end of tumor-related treatment, in cases of ORN (group 3) 12 months after completion of disease-related treatment. A total of 96 patients were included into this study. The mean age was 62.79 ± 8.93 years. The patients in groups 1 and 2 revealed a reduced quality of life, of a greater magnitude after radiation therapy. Patients felt that radiotherapy was much worse than surgery; however, half of the patients stated that they would repeat radiation therapy if necessary. The subjective evaluation of the HRQOL after surgery and radiotherapy was a valuable instrument for assessing the rehabilitation of patients in the context of their function and quality of life. Radiation therapy can be considered a trigger of functional limitations and emotional distress that contributes to decreased HRQOL in patients with head and neck cancer.

Superficial lateral sural artery free flap for intraoral reconstruction: anatomic study and clinical implications.

A posterolateral calf free flap is anatomically assessed and its usefulness for intraoral reconstruction is described.

Perforator flaps--how many perforators are necessary to keep a flap alive?

Perforator flaps are becoming increasingly important in reconstructive microsurgery because of their reduced donor-site morbidity. However, one drawback is partial necrosis caused by vasospasm or inconsistency of delicate perforator vessels. In this study we have evaluated the number and capacity of perforator vessels with respect to the size of a flap, and the influence of vascular endothelial growth factor (VEGF) on the capacity of perforators in a standard animal model. We realised an epigastric perforator flap 4cm×7cm in 36 rats. In 3 control groups (n=6 in each), flaps were raised based on 4, 2, or 1 perforator vessel(s), while all other perforators as well as the epigastric vessels were ligated. In three study groups (n=6 in each), set up in the same way as the control groups, we also injected a single dose of VEGF into the wound area. After one week, all areas of necrosis were assessed planimetrically. We also evaluated the wounds by laser Doppler flowmetry preoperatively and after one week, and by histological and immunohistochemical examination. An increased number of perforators, together with VEGF, was associated with a significant reduction in the areas of necrosis. This observation was particularly true in flaps based on only one perforator. The inclusion of additional perforators has a more important role in the success of a flap than theoretical models suggest. Proangiogenetic factors may improve the viability of perforator flaps.

Ketamine-Xylazine Anesthesia in Rats: Intraperitoneal versus Intravenous Administration Using a Microsurgical Femoral Vein Access.

BACKGROUND Ketamine-xylazine is a frequently used combination for anesthesia in microsurgically operated rats and can be administered by intraperitoneal (IP) or intravenous (IV) injection. Both methods are associated with relatively high misadministration rates. In the present study, we want to introduce a femoral vein access that requires microsurgical cannulation but enables a 100% administration rate. METHODS In this study, the maximal time of anesthesia was analyzed, time to response, latency time, and the total need for anesthetic agents in IP (n = 200) and IV (n = 40) anesthesia in Wistar rats for the purpose of microvascular operations. IV injections were achieved with an inserted microcatheter that was applied via a microsurgical femoral vein access. RESULTS The time needed for the placement of the microcatheter was 5.76 ± 0.89 minutes. Maximal time of anesthesia (IP vs. IV) was 7.02 ± 1.92 versus 21.78 ± 5.77 hours (p < 0.0001), time to response was 137.5 ± 3.91 versus 18 ± 2.18 seconds (p < 0.0001), latency time 35.53 ± 3.21 versus 27.8 ± 2.88 minutes (p < 0.0001), and total volume of anesthetic 1.42 ± 0.39 versus 2.78 ± 0.73 mL (p < 0.0001), respectively. CONCLUSION IV administration using the microsurgical femoral vein access is a feasible method with a quicker response rate and a 100% administration rate. Furthermore, it enables longer anesthesia, for example, complex microsurgical or other experimental procedures in the rat.

Indocyanine green videoangiography-assisted prediction of flap necrosis in the rat epigastric flap using the flow(®) 800 tool.

The decision to re‐operate on a potentially ischemic free flap remains challenging. Indocyanine green videoangiography (ICG) with the FLOW® 800 tool is a method which allows an immediate qualitative conclusion about the patency of an anastomosis. Is it also able to predict the outcome of potentially compromised vascular free flaps?

Free flap reconstruction for patients with bisphosphonate related osteonecrosis of the jaws after mandibulectomy

INTRODUCTION Bisphosphonate related osteonecrosis of the jaws (BRONJ) is a recognised unwanted effect of these drugs which affect bone remodelling. Treatment options range from conservative approaches through local bone debridement to free flap reconstruction following segmental resection. This current study aims to evaluate clinical outcomes after microvascular tissue transfer in BRONJ patients. MATERIAL AND METHODS A total of 212 BRONJ patients were included in this prospective investigation. Those who met defined inclusion criteria and received a surgical intervention were reviewed regularly during a follow-up period of at least 6 months. RESULTS Twenty-five patients (11.8%) received free flap reconstructions. A mean of 2.12 local debridements were performed before microvascular tissue transfer. A mean of 29.25% showed BRONJ recurrence after minimalist surgical intervention, compared to significantly less in patients after resection and free flap reconstruction. The postoperative fistula rate was significantly higher in patients, who received mucoperiosteal flaps. DISCUSSION This study underlines the importance and effectiveness radical resection and free flap reconstruction in the complex and challenging surgical treatment of BRONJ patients in a large patient cohort study. Nevertheless, all patients received radical intervention after failure of minimally invasive treatment. An individualized analysis and planning is necessary to identify appropriate patients for free flap reconstructions.