Implantable Doppler Research Articles

The Negative Pressure Wound Therapy for Flap Salvage

Negative Pressure Wound Therapy (NPWT) effectively manages complex wounds by promoting fluid drainage, stabilizing the wound environment, and reducing bacterial load. It aids in granulation tissue formation and modulation of inflammatory reactions. NPWT is increasingly used in reconstructive surgery, particularly in flap procedures, enhancing wound healing and cosmetic outcomes while reducing flap complications. Despite concerns about flap compromise, clinical trials demonstrate low flap loss rates with NPWT. Strategies like observation windows and implantable Doppler devices help overcome monitoring challenges. However, conclusive evidence regarding NPWT's safety and impact on flap vascularity is limited due to scarce studies. The study involved 40 healthy adult patients, mostly male, with soft tissue defects primarily caused by road traffic accidents. They were split into two groups: NPWT (25 patients) and conventional dressing (15 patients). The NPWT group was further categorized into high pressure (8 patients) and low pressure (17 patients) subgroups. Results showed lower flap edema in NPWT groups compared to controls, but high pressure NPWT led to higher flap ischemia and infection rates. Overall, low pressure NPWT yielded the best clinical and aesthetic outcomes with fewer complications. The study suggests a delayed NPWT approach and low-pressure settings for optimal vascular perfusion in Fasciocutaneous flaps, emphasizing the need for further trials to establish its efficacy and determine ideal pressure settings for different flap types.

V-113.1: Exploring the role of an implantable doppler probe as a blood flow-monitoring device in kidney transplant: A feasibility randomized controlled trial.

V-113.1: Exploring the role of an implantable doppler probe as a blood flow-monitoring device in kidney transplant: A feasibility randomized controlled trial.

P.177: The experiences of participation in a study investigating feasibility of the implantable doppler probe in kidney transplantation: An embedded qualitative study.

P.177: The experiences of participation in a study investigating feasibility of the implantable doppler probe in kidney transplantation: An embedded qualitative study.

The importance of ward-based education in the postoperative assessment of free flaps

Background: Despite the theoretical and practical advantages of adjunct-based free flap failure detection, the introduction of ultrasonographic techniques has not changed free flap failures rates and their use remains secondary to clinical assessment. Our study aims to develop an educational framework to improve the confidence of nursing staff caring for free flaps, with an emphasis on early detection of flap failure, thereby improving postoperative outcomes. Methods: Nursing staff in intensive care units and surgical wards caring for free flaps completed standardised questionnaires either before or after an educational seminar detailing clinical and Doppler assessment of free flaps. Differences between cohorts were summarised descriptively with frequencies and percentages. Overall confidence scores for pre-education and post-education cohorts were compared. Results: Overall, 173 responses were collected. Most staff were from intensive care units (n = 114) and almost one-third completed surveys following the educational intervention (n = 51). Microsurgical ward staff had more experience in the postoperative care of free flaps than intensive care unit staff (29% vs 18% had experience caring for > 50 free flap cases). Confidence in assessing a free flap by clinical, implantable Doppler or external Doppler ultrasound was universally increased among ward staff compared to intensive care unit staff (p ≤ 0.007). Altogether, 51 per cent of intensive care unit staff had never identified a failing flap compared with 35 per cent of ward staff. Education increased confidence in managing and escalating failing flaps unanimously. Most failing flaps were identified by clinical assessment alone or combined with adjunct-based methods (94%). Conclusion: This study demonstrates that the provision of targeted education for nursing staff, both in intensive care units and on surgical wards, is useful for increasing confidence in the clinical assessment and early detection of free flap compromise. Increased confidence and improved clinical assessment may allow for early intervention and improved salvage rates for a threatened free flap, thereby improving patient outcomes.

An overview of current assessment techniques for evaluating cutaneous perfusion in reconstructive surgery.

This article provides a comprehensive analysis of modern techniques used in the assessment of cutaneous flaps in reconstructive surgery. It emphasizes the importance of preoperative planning and intra- and perioperative assessment of flap perfusion to ensure successful outcomes. Despite technological advancements, direct clinical assessment remains the gold standard. We categorized assessment techniques into non-invasive and invasive modalities, discussing their strengths and weaknesses. Non-invasive methods, such as acoustic Doppler sonography, near-infrared spectroscopy, hyperspectral imaging thermal imaging, and remote-photoplethysmography, offer accessibility and safety but may sacrifice specificity. Invasive techniques, including contrast-enhanced ultrasound, computed tomography angiography, near-infrared fluorescence angiography with indocyanine green, and implantable Doppler probe, provide high accuracy but introduce additional risks. We emphasize the need for a tailored decision-making process based on specific clinical scenarios, patient characteristics, procedural requirements, and surgeon expertise. It also discusses potential future advancements in flap assessment, including the integration of artificial intelligence and emerging technologies.

Survey of Surgeon-reported Postoperative Protocols for Deep Inferior Epigastric Perforator Flap in Breast Reconstruction.

The use of deep inferior epigastric perforator (DIEP) flaps is a well-established breast reconstruction technique. A 29-question survey was e-mailed to 3186 active American Society of Plastic Surgeons members, aiming to describe postoperative monitoring practice patterns among surgeons performing DIEP flaps. From 255 responses (8%), 79% performing DIEP surgery were analyzed. Among them, 34.8% practiced for more than 20 years, 34.3% for 10-20 years, and 30.9% for less than 10 years. Initial 24-hour post-DIEP monitoring: intensive care unit (39%) and floor (36%). Flap monitoring: external Doppler (71%), tissue oximetry (41%), and implantable Doppler (32%). Postoperative analgesia: acetaminophen (74%), non-steroidal anti-inflammatory drugs (69%), neuromodulators (52%), and opioids (4.4%) were administered on a scheduled basis. On postoperative day 1, 61% halt intravenous fluids, 67% allow ambulation, 70% remove Foley catheter, and 71% start diet. Most surgeons discharged patients from the hospital on postoperative day 3+. Regardless of experience, patients were commonly discharged on day 3. Half of the surgeons are in academic/nonacademic settings and discharge on/after day 3. This study reveals significant heterogeneity among the practice patterns of DIEP surgeons. In light of these findings, it is recommended that a task force be convened to establish standardized monitoring protocols for DIEP flaps. Such protocols have the potential to reduce both the length of hospital stays and overall care costs all while ensuring optimal pain management and vigilant flap monitoring.

Flap monitoring in head & neck reconstructive surgery – A review of the literature

Microvascular free flap tissue transfer is a reliable technique for the reconstruction of orofacial defects, success rates have been cited as being between 96 and 98%, with vascular compromise requiring early return to theatre reported in 5–20% of cases across the literature. It has been described that the majority of free flap compromise occurs within the first 48 h post anastomosis, and that salvage rates are proportional with the timing of the vascular insult. Strategies adopted to identify early signs of compromise and hence improve the chances of flap survival are many, and protocols vary between units. On review of the literature, diligent bedside clinical monitoring of free flaps in the early post-operative period, seemed to facilitate detection of vascular compromise, allowing for early salvage, and hence better outcomes. Monitoring adjuncts such implantable doppler devices may prove helpful in such cases but false positives and negatives should be kept in mind. It would seem appropriate that future research should centre on evaluating adjunctive techniques to close bedside monitoring with a focus on clinically relevant outcome measures as well as cost/benefit analyses.

Supercharging DIEP Flaps Using Contralateral Superficial Inferior Epigastric Vein Grafts

Introduction: Venous congestion, even with a patent deep venous anastomosis, can afflict some DIEP (Deep Inferior Epigastric Perforator) flaps and various techniques of superficial venous supercharging have been described, although the indications for its use are not consensual. The main goal of this study is to confirm that superficial venous supercharge of DIEP flaps, utilizing the contralateral Superficial Inferior Epigastric Vein (SIEV) as an interposition vein graft, is feasible and functional. Materials and Methods: We retrospectively reviewed all DIEP flap breast reconstruction patients treated at our institution between June 2016 and December 2017 and that met all the inclusion criteria: Unilateral breast reconstruction with a DIEP flap; flap weighing more than 750 gm; supercharging of the ipsilateral superficial venous system; contralateral SIEV interposition graft; implantable doppler probe in the superficial system for at least 5 days. In the technique described here, the contralateral SIEV graft was harvested and anastomosed to the ipsilateral SIEV, obtaining this way a long vein that easily reaches the recipient vein (distal end of the Internal Mammary Vein - IMV). A Doppler probe was implanted in the superficial system, for at least 5 postoperative days, to monitor the function of this supercharging. We also analyzed the patient’s history, flaps weight, number and perforator rows, recipient vessels, SIEV graft length and diameter and all perioperative complications. Results: Ten patients met all inclusion criteria. They were treated using this technique and analyzed. Two patients had some type of alteration of the Doppler signal and clinical signs of venous congestion. They were surgically revised with success and were analyzed in detail. No total or partial flap failures were found. Clinical fat necrosis was also absent. Conclusion: This technique seems to be feasible, functional and adds an extra length to ipsilateral SIEV to reach a recipient vein. This way, the flap inset is not compromised by a short SIEV. No further significant morbidity is added for SIEV harvest that is in the same operative field, unlike the saphenous or cephalic veins. In selected patients, it could be an alternative supercharging technique.

Examining Trends in Implantable Arterial Doppler Usage Among North American Head and Neck Microsurgeons: A Survey Study

There are variations in implantable arterial Doppler usage for microvascular free tissue monitoring among North American surgeons. Identifying utilization trends among the microvascular community may elucidate practice patterns that may be useful in determining protocols. Furthermore, study of this information may yield novel and unique applications in other disciplines such as vascular surgery. Electronically disseminated survey study shared with a large database of North American head and neck microsurgeons. Seventy four percent of respondents use the implantable arterial Doppler; 69% report use in all cases. Ninety five percent remove the Doppler by the seventh postoperative day. All respondents felt that the Doppler did not impede care progression. Any implication of flap compromise was followed with a clinical assessment in 100% of respondents. If viable, 89% would continue monitoring after clinical examination, while 11% would take the patient for exploration regardless of clinical examination. The efficacy of the implantable arterial Doppler has been established in the literature and is supported by the results of this study. Further investigation is required to establish a consensus on use guidelines. The implantable Doppler is more often used in conjunction with rather than substitution for clinical examination.

Exploring Views and Expectations of Clinicians, Nurses, and Kidney Transplant Recipients Regarding Protocol Development of a Study to Investigate Feasibility of the Implantable Doppler Probe in Kidney Transplantation: Patient-Public Involvement Consultations.

The shortage of donor organs is the most limiting factor in kidney transplant practice today. New monitoring technologies are being investigated to reduce graft loss due to vascular complications. We assessed the feasibility of a novel blood flow monitoring device, the implantable Doppler probe, in kidney transplant surgery. This patient-public involvement consultation explored the views and expectations of the stakeholders (kidney transplant recipients, surgeons, clinicians, and nurses with direct experience of the implantable Doppler probe) on the protocol development of our feasibility study. Our objective was to improve the protocol, understand stakeholder perceptions regarding research in postoperative graft surveillance, and identify potential confounding factors to the research and challenges to implementation of implantable Doppler probe in clinical practice. We conducted semi-structured interviews containing open-ended questions with 12 stakeholders. We performed thematic analysis of the data at the latent level by an inductive approach according to a 6-phase guide by Braun and Clarke using NVivo 12 software. Three key themes emerged. (1) Experiences with the implantable Doppler probe as a monitoring device showed that it was well received by the patients; however, there was a clinical equipoise among the health care professionals. (2) Recognition of the need for research in the early postoperative graft monitoring displayed stakeholder understanding regarding the role of a blood flow monitoring device to improve surgical outcomes. (3) Recommendations for smooth conduct of the proposed study include suggestions for improvement of the study protocol, informative sessions for the patients and nurses, and innovative ideas to improve the monitoring device. Patient-public involvement consultation was crucial for the research design of our proposed feasibility study. Useful strategies and a patient- centered approach were incorporated to mitigate the potential challenges to the conduct of the research.

Monitoring Buried Flap in Pharyngeal Defect Reconstruction.

Laryngopharyngeal resection with permanent tracheostoma for advanced laryngeal malignancy is a reconstructive challenge. A thin fasciocutaneous flap, such as a radial artery forearm flap, is best suited to restore the continuity of partial pharyngeal defects. However, the flap skin surface forms the lining precluding its monitoring. Postoperative monitoring of these buried flaps has not been satisfactory, and various described methods include direct visualization by an endoscope, implantable Doppler, manipulation of skin paddle, external skin bridge segment, venous flow through flap, and so on.[1] [2] [3] [4] Each of these calls for careful planning, design, and execution.

The Use of the Implantable Doppler Probe as a Blood Flow Monitoring Device in Clinical Settings: A Narrative Review of the Evidence.

In the past decade, the implantable Doppler probe has been studied widely as a blood flow-monitoring device in reconstructive and transplant surgical specialities. Its utility as an effective postoperative monitoring technique is still debatable, with no clear guidelines in clinical practice. Here, we mapped the current evidence on the usefulness of the implantable Doppler probe as a blood flow-monitoring device. The objective was to present an up-to-date assessment of the benefits and limitations of using implantable Doppler probes in clinical and experimental clinical settings. We conducted a literature search using the Cochrane Library and Healthcare Databases Advanced Search and using implantable Doppler probe, transplant, graft, and flap as key words. The search yielded 184 studies, with 73 studies included after exclusions. We evaluated, synthesized, and summarized the evidence from the studies in tabular form. There is clinical equipoise regarding the effectiveness of implantable Doppler probe as a flow sensing technique. The main reason is the lack of information and gaps in the evidence regarding the benefits and limitations of using implantable Doppler probes in clinical practice. The implantable Doppler probe has the potentialto be used as an adjunctpostoperativeblood flow-monitoring device. However, keeping in view of technical limitations, its signals should be interpreted alongside traditional clinical assessment techniques to determine the patency of microvascular anastomosis. Although evidence in this review will inform clinical practice in transplant and reconstructive surgical specialties, a prospective randomized controlled study with a larger patient cohort is required to evaluate the effectiveness of this probe in clinical settings.

Near infrared spectroscopy in monitoring of head and neck microvascular free flaps.

Microvascular free‑flap monitoring is crucial to the early detection of flap failure and increases the chance of early intervention in case of disruption of perfusion to a flap. Many clinical alternatives to classical clinical flap monitoring have been proposed, such as color duplex ultrasonography, handheld Doppler, flap thermometry, or implantable Doppler flowmetry. Early detection of critical changes in tissue oxygenation can lead to successful surgical intervention when problems with flap nutrition arise. Our clinical study seeks to investigate dynamic monitoring of free flaps with near‑infrared spectroscopy (NIRS). NIRS is a non-invasive instrumental technique used for continuous monitoring of peripheral tissue oxygenation (StO2) and microcirculation. All patients were included prospectively from one clinical center. During the clinical research period, 18 patients underwent extraoral head and neck reconstruction with one of three types of free flap, namely with radial forearm free flap (RFFF), anterolateral thigh flap (ALT) or fibula free flap (FFF). Measurements of flap perfusion were taken using NIRS during intraoperative and postoperative phases for 71 hours on average. A total of 6 perfusion disorders were recorded, of which three originated from microanastomoses and three from postoperative bleeding and compression of pedicle. NIRS showed characteristic changes in all 6 cases that were returned to the operating theatre owing to pedicle compromise. In these cases, NIRS had detected the pedicle compromise before it was clinically identified. A single StO2 monitoring was able to detect the vascular compromise with 100% sensitivity and 95.65% specificity. None of the cases were falsely positive. In our study, all compromised flaps were accurately identified by means of NIRS. In most cases, the changes in oxygen saturation became evident on NIRS prior to being clinically observed. In our study, the continuous NIRS monitoring securely detected the early stages of arterial and venous thromboses or pedicle compression. The most important aspects of monitoring the flaps´ microvascular perfusion and vitality by means of NIRS lie in its function of recording the dynamics of changes in the values ​​of absolute oxygen saturation (StO2> 50%) alongside with detecting a 30% decrease in tissue saturation over a 60‑minute interval (60 min StO2 >30%) before the clinical changes in the microvascular flap become observable. In cases of pedicle compression, the average time of appearance of signs of StO2 values dropping below the reference interval (as detected by NIRS) was 1:29:02 hour (SD= 0:58:42 h) prior to the occurrence of any clinical signs, while in cases of microvascular anastomosis complications, it was 0:35:23 hour (SD=0:08:30 h) (SD = 0:08:30 h) (Tab. 3, Fig. 7, Ref. 42).

Does Fitzpatrick Score Predict Flap Loss? Microsurgical Breast Reconstruction Outcomes of Varying Skin Color.

This is a retrospective study conducted on patients who underwent any type of autologous flap breast reconstruction performed by the two senior authors at an academic center between January 2010 and December 2021. The sole primary outcome variable was flap loss. Patient skin tone was assessed using the Fitzpatrick scale on clinical photographs of patients. A total of 1115 pateints underwent autologous flap breast reconstruction, of which only 56 met both exclusion and inclusion criteria with 58 individual breasts being included in the final study population. The most common race of subjects was White (n = 33; 56.9%) while the most common Fitzpatrick score skin tone was type II (n = 22; 37.9%). The Cochran-Armitage test of trend showed a statistically significant linear trend, P = 0.006, with darker Fitzpatrick score skin tones associated with a higher proportion of flap loss in patients who had vascular compromise. A logistic regression showed that none of the predictor variables were significant. Patients with darker Fitzpatrick skin tones were associated with flap loss after vascular compromise. To prevent flap loss in patients who have darker Fitzpatrick score skin tones, more aggressive flap monitoring should be taken into consideration in the immediate postoperative setting.

An Analysis of the Implantable Doppler Probe for Postoperative Free-Flap Monitoring and Risk Factor Analysis for Revision Surgery in Facial Reanimation Surgery.

Background: Postoperative monitoring after free functional gracilis transfer for smile reconstruction in long-standing facial paralysis is challenging as clinical assessments are limited. Objective: In patients receiving free gracilis transfer for smile reconstruction, we compared the implantable Doppler probe with a handheld Doppler/intraoperative blood flow regarding the reliability in detecting perfusion compromised free flaps. Methods: In a retrospective cohort study we analyzed facial paralysis patients who, after free functional smile reconstruction, were postoperatively monitored using the implantable Doppler probe. Furthermore, we conducted a multiple logistic regression analysis on risk factors for vascular complications. Results: We included 119 patients who received 125 free functional gracilis transfers. The sensitivity of the implanted Doppler probe was 1.0 and the specificity 0.88. There were no false-negative results (negative predictive value = 1.0). The calculated positive predictive value was 0.41. We used a handheld Doppler device to verify signal changes. The combined positive predictive value of both tests was 0.91. Previous surgery in the surgical field was a risk factor for impaired blood flow. Conclusions: The implantable Doppler probe proved to be a reliable tool for postoperative monitoring of free functional gracilis transfer in facial reanimation surgery. Special care should be taken in preoperated patients.

Complications related to the Cook-Swartz implantable Doppler probe use in head and neck microvascular reconstruction: a systematic review.

Vascular perfusion research has been dedicated to identify inexpensive, effective, and easy to use methods to assess free flap perfusion for both buried and non-buried flaps. Systematic review of complications in patients underwent Head and Neck microsurgical reconstruction and vascular implantable Doppler monitoring. Sixteen articles were included for qualitative analysis. 2535 (92.2%) patients received IDP monitorization. Venous thrombosis was the most common vascular complication effecting 28 (1.1%). Regarding complications potentially related to the use of the IDP, just one study described the presence of granuloma formation along the suture line in 2 (0.07%) patients. Our findings indicated that Cook-Swartz IDP will represents a safe and effective device for FF monitoring in HN reconstructive micro-surgery. A detailed prospective registration of the results and complications related to the use of IDP remains mandatory to precisely estimate results, cost, and complications.

Implantable Doppler Probe as a Vascular Monitoring Device in Kidney Transplant Patients: Investigation of Use at a Single Center.

Vascular complications account for 30% to 35% of total kidney grafts lost during the first 3 months posttransplant. Early detection of vascular complications allows an opportunity for prompt intervention, which is critical to reducing graft loss. In this study, we evaluated the usefulness of an implantable Doppler probe as a vascular monitoring device in kidney transplant patients. An implantable Doppler probe is used intermittently for postoperative monitoring of kidney transplant patients at our center. In this retrospective study, we analyzed prospectively maintained medical data in which we compared clinical outcomes of kidney transplant recipients who had postoperative implantable Doppler probe monitoring versus standard care clinical observation. Between January 2016 and October 2021, 324 kidney transplant patients were seen at our center. Patients were divided into 2 groups: group 1 (n = 194; 60%) included kidney transplant recipients with postoperative implantable Doppler probe monitoring and group 2 (n = 129; 40%) included kidney transplant recipients with standard care clinical observation. We compared number of vascular complications, number of departmental ultrasonographic scans required posttransplant, and graftloss at 3 months between the 2 groups. Vascular complications were identified in 13.5% of total patients, with graft loss identified in 2.1%. Both groups were similar in demographical characteristics. Group 1 had more vascular complications (17.5% vs 9.3%; relative risk = 1.88), fewer ultrasonographic scans during the first 24 hours posttransplant (71.1% vs 83.7%; relative risk = 0.84), and lower graft loss (1.5% vs 3.1%; relative risk = 0.48) than group 2. All probes were removed safely after 72 hours, and no complications related to the device were reported. The monitoring device may be used as an additional adjunct for graft monitoring in kidney transplant patients. Further controlled studies are warranted to evaluate this device in clinical practice.

Success of Implantable Doppler Probes for Monitoring Buried Free Flaps.

The objective of this study is to describe the operative success of completely buried free flaps and to determine the safety/reliability of using implantable dopplers for postoperative monitoring in completely buried free flaps. A retrospective chart review was conducted from 2014 to 2020. Patients were included who had implantable dopplers placed for monitoring a completely buried free flap without a visible skin paddle. Single academic cancer hospital. Patient charts were reviewed to determine flap viability after surgery, need for reoperation, and ability of implanted doppler probes to detected change in free flap status. A total of 65 patients were included. Locations of flaps were as follows: pharynx, 76.9%; skull base, 7.7%; trachea, 6.2%; esophagus, 4.6%; and facial reanimation, 4.6%. Types of free flaps performed included radial forearm (50.8%), anterolateral thigh (44.6%), and gracilis (4.6%). One patient (1.5%) returned to the operating room for vascular compromise, which was accurately detected by the implantable doppler and salvaged. All free flaps were viable upon hospital discharge based on clinical examination and implantable doppler signals. There were no complications related to implantable doppler use. Implantable dopplers are an effective method for evaluating postoperative success of completely buried free flaps. In our series utilizing implantable dopplers, buried free flap survival was higher than traditionally thought. The use of implanted dopplers for monitoring buried free flaps allows for an effective, cosmetically appealing, and simplified reconstructive technique.

Implantable Doppler Removal After Free Flap Monitoring Among Head and Neck Microvascular Surgeons.

Investigate current practice patterns of head and neck microvascular reconstructive surgeons when removing an implantable Doppler after free flap surgery. Cross-sectional survey study. Survey distributed to head and neck microvascular reconstructive surgeons. Data regarding years performing free tissue transfer, case numbers, management of implantable Doppler wire, and complications were collected. Eighty-five responses were analyzed (38,000 cases). Sixty-six responders (77.6%) use an implantable Doppler for postoperative monitoring, with 97% using the Cook-Swartz Doppler Flow Monitoring System. Among this group, 65.2% pull the wire after monitoring was complete, 3% cut the wire, and 31.8% have both cut and pulled the wire. Of those who have cut and pulled the wire, 48% report cutting and pulling the wire with equal frequency, 43% formerly pulled the wire and now cut the wire, and 9% previously cut the wire but now pull the wire. Of those who pull the wire, there were two injuries to the pedicle requiring return to the operating for flap salvage, and one acute venous congestion. Of the nine who previously pulled the wire, six (67%) cited concerns with major bleeding/flap compromise as the reason for cutting the wire. In this study, most surgeons use an implantable Doppler for monitoring of free flaps postoperatively. In extremely rare instances, pulling the implantable Doppler wire has resulted in flap compromise necessitating revision of the vascular anastomosis. Cutting the wire and leaving the proximal portion in the surgical site has been adopted as a management option. 4 Laryngoscope, 132:554-559, 2022.

The use of sentinel skin islands for monitoring buried and semi-buried micro-vascular flaps. Part I: Summary and brief description of monitoring methods.

Micro-vascular flaps have been used for the repair of challenging defects for over 45 years. The risk of failure is reported to be around 5-10% which despite medical and technical advances in recent years remains essentially unchanged. Precise, continuous, sensitive and specific monitoring together with prompt notification of vascular compromise is crucial for the success of the procedure. In this review, we provide a classification and brief description of the reported methods for monitoring the micro-vascular flap and a summary of the benefits over direct visual monitoring. Over 40 different monitoring techniques have been reported but their comparative merits are not always obvious. One looks for early detection of a flap's compromise, improved flap salvage rate and a minimal false-positive or false-negative rate. The cost-effectiveness of any method should also be considered. Direct visualisation of the flap is the method most generally used and still seems to be the simplest, cheapest and most reliable method for flap monitoring. Considering the alternatives, only implantable Doppler ultrasound probes, near infrared spectroscopy and laser Doppler flowmetry have shown any evidence of improved flap salvage rates over direct visual monitoring.