Postoperative monitoring of free flaps in autologous breast reconstruction: a multicenter comparison of 398 flaps using clinical monitoring, microdialysis, and the implantable Doppler probe

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.

The learning curve of the MS-TRAM/DIEP breast reconstruction by dual-trained breast surgeons

BACKGROUND

Breast cancer surgeries involving MS-TRAM/DIEP breast reconstruction has traditionally been collaborative efforts between breast surgeons and plastic surgeons. However, in our institution, this procedure is performed by dual-trained breast surgeons who are proficient in both breast surgery and MS-TRAM/DIEP breast reconstruction. This study aims to provide insights into the learning curve associated with this surgical approach.

MATERIALS AND METHODS

We included eligible breast cancer patients who underwent MS-TRAM/DIEP breast reconstruction by dual-trained breast surgeons between 2015 and 2020 at our institution. We present the learning curve of this surgical approach, with a focus on determining factors affecting flap harvesting time, surgery time, and ischemic time. Additionally, we assessed the surgical complication rates.

RESULTS

A total of 147 eligible patients were enrolled in this study. Notably, after 30 cases, a statistically significant reduction of 1.7 h in surgery time and 21 min in ischemic time was achieved, signifying the attainment of a plateau in the learning curve. And the major and minor complications were comparable between the early and after 30 cases.

CONCLUSION

This study explores the learning curve and feasibility experienced by dual-trained breast surgeons in performing MS-TRAM/DIEP breast reconstruction.

TRIAL REGISTRATION

NCT05560633.

Assessing Hand Perfusion With Eulerian Video Magnification and Waveform Extraction

PURPOSE

Timely and accurate triage of upper extremity injuries is critical, but current perfusion monitoring technologies have shortcomings. These limitations are especially pronounced in patients with darker skin tones. This pilot study evaluates a Eulerian Video Magnification (EVM) algorithm combined with color channel waveform extraction to enable video-based measurement of hand and finger perfusion.

METHODS

Videos of 10 volunteer study participants with Fitzpatrick skin types III-VI were taken in a controlled environment during normal perfusion and tourniquet-induced ischemia. Videos were EVM processed, and red/green/blue color channel characteristics were extracted to produce waveforms. These videos were assessed by surgeons with a range of expertise in hand injuries. The videos were randomized and presented in 1 of 3 ways: unprocessed, EVM processed, and EVM with waveform output (EVM+waveform). Survey respondents indicated whether the video showed an ischemic or perfused hand or if they were unable to tell. We used group comparisons to evaluate response accuracy across video types, skin tones, and respondent groups.

RESULTS

Of the 51 providers to whom the surveys were sent, 25 (49%) completed them. Using the Pearson χ2 test, the frequencies of correct responses were significantly higher in the EVM+waveform category than in the unprocessed or EVM videos. Additionally, the agreement was higher among responses to the EVM+waveform questions than among responses to the unprocessed or EVM processed. The accuracy and agreement from the EVM+waveform group were consistent across all skin pigmentations evaluated.

CONCLUSIONS

Video-based EVM processing combined with waveform extraction from color channels improved the surgeon's ability to identify tourniquet-induced finger ischemia via video across all skin types tested.

CLINICAL RELEVANCE

Eulerian Video Magnification with waveform extraction improved the assessment of perfusion in the distal upper extremity and has potential future applications, including triage, postsurgery vascular assessment, and telemedicine.

DIEP flap perfusion assessment using microdialysis versus Doppler ultrasonography: A comparative study

BACKGROUND

The increasing number of buried free-tissue transfer procedures and the need for an objective method to evaluate vascular complications of free flaps has led to the development of new technologies. Microdialysis has been used to monitor free flaps using interstitial biological markers. Previous uses mainly focused on muscular flaps. Our aim is to compare external Doppler ultrasonography (EDU) evaluation versus microdialysis in the early follow-up of adipocutaneous flaps, and propose an efficient postoperative monitoring protocol.

METHODS

We retrospectively assessed 68 consecutive DIEP flaps (50 patients) performed between January 2019 and March 2021. All flaps received standardized post-operative monitoring using clinical signs, EDU and microdialysis. Glucose and lactate concentrations were assessed using glucose <1 mmol/L and lactate >6 mmol/L as ischemic trend thresholds. We calculated Glucose/Lactate ratio as a new parameter for the assessment of flap viability.

RESULTS

Among all the 68 flaps, two flaps returned to the operative theater when a combination of unsatisfactory microdialysis values and clinical/EDU signs identified vascular impairment; only one developed total flap necrosis. Reoperation rate was 2.94% with an overall flap success rate of 98.53%. External Doppler ultrasonography had 100% sensitivity and 82% specificity, while microdialysis had 100% sensitivity and 100% specificity.

CONCLUSIONS

Microdialysis values proved flap viability sooner than external Doppler ultrasonography, making it an excellent tool for post-operative monitoring. With the appropriate thresholds for glucose and lactate concentrations, and glucose/lactate ratio used as a new parameter, it can help potentially avoiding unnecessary re-explorations, and reducing flap ischemia times.

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

Background

The use of deep inferior epigastric perforator (DIEP) flaps is a well-established breast reconstruction technique.

Methods

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.

Results

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.

Conclusions

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.

Implantable arterial doppler efficacy in free flap reconstruction: A systematic review and meta-analysis

The implantable arterial doppler (IAD) is frequently used to postoperatively monitor free flaps with high accuracy, but there are no guidelines for its use. Bedside exam is used adjunctively to determine necessary intervention. This systematic review seeks to discover why the doppler is used adjunctively despite its established record of accuracy. Criteria for inclusion and exclusion were established. In total, 280 articles were found on PubMed and Web of Science, then screened accordingly. Data from 22 articles were analyzed using a bivariate hierarchical random effects model. Twenty-two studies yielded 2996 total patients undergoing 3127 free flap procedures. The meta-analysis found a high sensitivity of 0.809 (95% CI = 0.709, 0.880) and specificity of 0.966 (95% CI = 0.947, 0.979). False-positive rate was found to be 0.034 (95% CI = 0.021, 0.053). Positive and negative predictive values were 0.711 (95% CI = 0.581, 0.817) and 0.979 (95% CI = 0.966, 0.988). Positive and negative likelihood ratios were 24.7 (95% CI = 14.5, 39.5) and 0.20 (95% CI = 0.12, 0.30). The established efficacy of the IAD is supported by this study. Clinical exams may remain as the final adjunct due to the risks of inaccurate IAD signals. Further studies are warranted to optimize its use for future practice guidelines.

A Prospective Cohort Study Re-examining Tissue Oximetry Monitoring in Microsurgical Breast Reconstruction

BACKGROUND

The goal of inpatient monitoring after microsurgical breast reconstruction is to detect vascular compromise before flap loss. Near-infrared tissue oximetry (NITO) is commonly used for this purpose, but recent reports challenge its specificity and utility in current practice. Fifteen years after Keller published his initial study using this technology at our institution, we re-evaluate the role and limitations of this popular monitoring device.

METHODS

A 1-year prospective study was performed for patients undergoing microsurgical breast reconstruction and monitored postoperatively using NITO. Alerts were evaluated, and clinical endpoints relating to an unplanned return to the operating room or flap loss were recorded.

RESULTS

A total of 118 patients reconstructed with 225 flaps were included within the study. There were no cases of flap loss at the time of discharge. There were 71 alerts relating to a drop in oximetry saturation. Of these, 68 (95.8%) were deemed to be of no significance. In 3 cases (positive predictive value of 4.2%), the alert was significant, and there were concerning clinical signs apparent at that point. A sensor in an inframammary fold position was associated with nearly twice the average number of alerts as compared with areolar or periareolar positions ( P = 0.01). In 4 patients (3.4%), a breast hematoma required operative evacuation, and these cases were detected by nursing clinical examination.

CONCLUSIONS

The monitoring of free flaps after breast reconstruction through tissue oximetry shows a poor positive predictive value for flap compromise and requires clinical corroboration of alerts but missed no pedicle-related adverse events. With a high sensitivity for pedicle-related issues, NITO may be helpful postoperatively, but the exact timeframe for use must be weighed at the institutional level.

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

OBJECTIVES

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.

MATERIALS AND METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Diagnostic Accuracy of Microdialysis in Postoperative Flap Monitoring

Postoperative monitoring plays an important role in achieving success in microvascular free tissue transfer. A systematic review was designed to evaluate the clinical outcomes of microdialysis in flap monitoring and a meta-analysis was conducted for diagnostic accuracies. The search terms "microdialysis" and "flap" were used in a PubMed and Scopus search, resulting in 60 and 78 results, respectively. Among 78 titles, 15 articles were excluded. Among 63 abstracts, 43 abstracts were excluded. From 20 full texts, 7 articles were excluded because they did not have sufficient content (ie, the statistical values in question). A systematic review was conducted of the final 13 articles. The overall sensitivity was 97.24% [95% confidence interval (CI)=93.67%-99.10%]. Eleven of the 13 studies showed 100% sensitivity and 2 studies had 2 and 3 false negative results, resulting in sensitivity values of 85.8% and 95.3%. Specificity ranged from 91.89% to 100%, and the overall value was 98.15% (95% CI=96.80%-99.04%). The positive predictive value ranged from 84.62% to 100%, with an overall value of 93.62% (95% CI=89.33%-96.26%). The negative predictive value ranged from 94.44% to 100%, with an overall value of 99.22% (95% CI=98.17%-99.67%). The overall flap success rate (survival rate) was 93.7% (786/839). The lowest flap survival rate was 86.7% and the highest was 100%. Microdialysis provides excellent diagnostic accuracy and enables the early detection of ischemia in postoperative flap monitoring. Although microdialysis is not the most popular choice among surgeons, it should be considered adjacent to conventional clinical monitoring. Cost-effectiveness, availability, and ease of application remain hurdles.

Nipple-sparing mastectomy with immediate breast reconstruction with a deep inferior epigastric perforator flap without skin paddle using delayed primary retention suture

BACKGROUND

This study investigated the outcomes of nipple-sparing mastectomy (NSM) with a deep inferior epigastric perforator (DIEP) flap using delayed primary retention suture (DPRS) to achieve superior breast esthetics.

METHODS

Between December 2010 and March 2021, patients who underwent NSM with DIEP flap were inset with or without a skin paddle (using DPRS) as Group A or B, respectively. Demographics, operative findings, complications, BREAST-Q questionnaire, and Manchester scar scale were compared between two groups.

RESULTS

Twelve patients underwent 12 unilateral reconstructions in Group A, while 12 patients underwent 13 DIEP flaps in Group B. There was no significant difference in demographics, ischemia time, flap-used weight and percentage, complications of hematoma, infection, re-exploration, partial flap loss, and total flap loss (All p > 0.05, respectively). At a mean 9 months of follow-up, the Breast-Q "Satisfaction with surgeon" domain was significant in Group B (p = 0.04). At a mean 12 months of follow-up, the overall Manchester scar scale of 10.3 in Group B was statistically superior to 12.6 in Group A (p = 0.04).

CONCLUSIONS

The NSM with a DIEP flap using DPRS is a reliable and straightforward technique. It can provide greater cosmesis of the reconstructed breast mound in a single-stage procedure.

Intraoperative near-infrared spectroscopy for pedicled perforator flaps: a possible tool for the early detection of vascular issues

Background

Pedicled perforator flaps can present postoperative complications similar to those encountered in free flap surgery. Beyond a clinical evaluation, there is still no reliable technical aid for the early prediction of vascular issues. The aim of this study was to assess the support of near-infrared spectroscopy technology as an intraoperative tool to anticipate postsurgical flap ischemia.

Methods

We prospectively enrolled 13 consecutive patients who were referred to our hospital from March 2017 to July 2018 and required a reconstructive procedure with a pedicled fasciocutaneous perforator flap. We measured flap peripheral capillary oxygen saturation (SpO₂) in each patient with a Somanetics INVOS 5100C Cerebral/Somatic Oximeter (Medtronic), both before and after transposition. Patient demographics, operative data, and complications were then recorded during the following 6 months. We analyzed the data using the Wilcoxon signed-rank test and linear regression.

Results

The mean flap SpO₂ before and after transposition was 92%±3% and 78%±19%, respectively. The mean change in SpO₂ was 14%±17%, with a range of 0% to 55%. The change in saturation and mean saturation ratio were significantly different between patients with and without postoperative flap necrosis.

Conclusions

An immediate quantitative analysis of flap peripheral capillary SpO₂ after transposition has never before been described. In our experience, an intraoperative drop in SpO₂ equal to or greater than 15%–20% predicted vascular complications in pedicled perforator flaps. Conversely, flap size and rotation angle were not correlated with the risk of flap necrosis.

Macrophage Migration Inhibitory Factor-An Innovative Indicator for Free Flap Ischemia after Microsurgical Reconstruction

(1) Background: Nowadays, the use of microsurgical free flaps is a standard operative procedure in reconstructive surgery. Still, thrombosis of the microanastomosis is one of the most fatal postoperative complications. Clinical evaluation, different technical devices and laboratory markers are used to monitor critical flap perfusion. Macrophage migration inhibitory factor (MIF), a structurally unique cytokine with chemokine-like characteristics, could play a role in predicting vascular problems and the failure of flap perfusion. (2) Methods: In this prospective observational study, 26 subjects that underwent microsurgical reconstruction were observed. Besides clinical data, the number of blood leukocytes, CRP and MIF were monitored. (3) Results: Blood levels of MIF, C-reactive protein (CRP) and leukocytes increased directly after surgery. Subjects that needed surgical revision due to thrombosis of the microanastomosis showed significantly higher blood levels of MIF than subjects without revision. (4) Conclusion: We conclude that MIF is a potential and innovative indicator for thrombosis of the microanastomosis after free flap surgery. Since it is easy to obtain diagnostically, MIF could be an additional tool to monitor flap perfusion besides clinical and technical assessments.

Monitoring Breast Reconstruction Flaps Using Near-Infrared Spectroscopy Tissue Oximetry

Free flap reconstruction is a common procedure with success rates greater than 99%. However, vascular complications may occur, resulting in flap failure. For this reason, early detection of vascular compromise is crucial for flap salvage. Vascular complications may be detected early by monitoring tissue oximetry parameter changes using near-infrared spectroscopy (NIRS). This method of noninvasive monitoring can evaluate changes in flap oxygenation levels caused by arterial and venous thrombosis before surgical reexploration. The goal of this study was to assess the validity of using NIRS oximetry for monitoring free flaps. We conducted a prospective cohort observational study of 10 patients undergoing breast reconstruction. We used the INVOS 7100 cerebral oximetry monitoring system (Medtronic, Dublin, Ireland) to provide 24-hr continuous postoperative monitoring of flap perfusion and compared the data with clinical assessment findings. The median patient age was 57 years (range = 41-61 years). Patients underwent immediate breast reconstruction with deep inferior epigastric perforator (DIEP) flap surgery (n = 4), delayed reconstruction with DIEP flap surgery (n = 4), transverse upper gracilis flap surgery (n = 1), and latissimus dorsi flap with lipofilling (n = 1). We successfully monitored all 10 flaps for 24 hr postoperatively. The overall flap survival rate was 100%. Findings of clinical examination, Doppler studies, and surgical outcome were consistent with NIRS monitoring. In conclusion, NIRS tissue oximetry could potentially provide a noninvasive method for effective postoperative monitoring of free flaps.

A paintable phosphorescent bandage for postoperative tissue oxygen assessment in DIEP flap reconstruction

Flaps are common in plastic surgery to reconstruct large tissue defects in cases such as trauma or cancer. However, most tissue oximeters used for monitoring ischemia in postoperative flaps are bulky, wired devices, which hinder direct flap observation. Here, we present the results of a clinical trial using a previously untried paintable transparent phosphorescent bandage to assess the tissue's partial pressure of oxygen (pO₂). Statistical analysis revealed a strong relationship (P < 0.0001) between the rates of change of tissue oxygenation measured by the bandage and blood oxygen saturation (%stO₂) readings from a standard-of-care ViOptix near-infrared spectroscopy oximeter. In addition, the oxygen-sensing bandage showed no adverse effects, proved easy handling, and yielded bright images across all skin tones with a digital single-lens reflex (DSLR) camera. This demonstrates the feasibility of using phosphorescent materials to monitor flaps postoperatively and lays the groundwork for future exploration in other tissue oxygen sensing applications.

Cook-Swartz Doppler Probe Surveillance for Free Flaps-Defining Pros and Cons

Introduction  The main postoperative complication of free flaps is perfusion compromise. Urgent intervention is critical to increase the chances of flap survival. Invasive flap perfusion monitoring with direct blood flow feedback through the Cook–Swartz Doppler probe could enable earlier detection of perfusion complications.

Materials and Methods  Between 2012 and 2016, 35 patients underwent breast reconstruction or defect coverage after trauma with a deep inferior epigastric perforator, anterolateral thigh, transverse musculocutaneous gracilis, gracilis, or latissimus dorsi flap in our department. All flaps were monitored with a Cook–Swartz probe for 10 days postoperatively. The 20 MHz probe was placed around the arterial–venous anastomosis. A flap monitoring protocol was established for standardized surveillance of postoperative perfusion. In the event of probe signal loss, immediate surgical revision was initiated.

Results  Signal loss was detected in 8 of the 35 cases. On return to the operating room, six were found to be true positives (relevant disruption of flap perfusion) and two were false positives (due to Doppler probe displacement). There were also two false negatives, resulting in a slowly progressive partial flap loss. Flap perfusion was restored in three of the six cases (50%) identified by the probe. Following surgical intervention, three of the six cases had persistent problems with perfusion, resulting in two total flap losses and one partial flap necrosis leading to an overall 5.7% total flap loss.

Conclusion  Postoperative flap perfusion surveillance is a complex matter. Surgical experience is often helpful but not always reliable. The costs, false-positive, and false-negative rates associated with invasive perfusion monitoring with Cook–Swartz probe make it most appropriate for buried flaps.

Level of Evidence  This is an original work.

Retrospective evaluation of diagnostic accuracy of free flap monitoring with the Cook-Swartz-Doppler probe in head and neck reconstruction

The Cook-Swartz-Doppler probe is an easy to handle and reliable tool for free flap monitoring. In the head and neck region different confounders can affect the read out. We therefore analyzed the use of the Doppler probe regarding these potential difficulties and to compare the diagnostic accuracy in arterial or venous monitoring of free flaps in the head and neck region. A retrospective study was performed in which all patients were included who underwent free flap surgery in the head and neck region in the Department of Plastic Surgery and the Department of Maxillofacial Surgery of our institution between 2010 and 2018 and were monitored with an implanted Doppler probe. 147 free tissue transfers were included. No significance was found for arterial and venous placement of the Doppler probe for sensitivity (artery 83.3%; vein 84.6%; p = 0.87), specificity (artery 89.2%; vein 96.1%; p = 0.17) and negative predictive value (artery 96.7%; vein 94.2%; p = 0.55). A better positive predictive value for placing the Doppler probe around the artery (82.7%) than the vein (61.1%) was found in our study (p = 0.056). The better positive predictive value in arterial monitoring suggests that this is the more reliable measuring method to assess flap perfusion in the head and neck region.

Negative pressure-induced hyperemia, a new modality in the monitoring of skin paddle containing free flaps

BACKGROUND

In free tissue transfer, monitoring is paramount to timely detect vascular complications. Although various technical methods have been introduced, clinical flap monitoring and, particularly, capillary refill test (CRT) remain the gold standard. In pale flaps, CRT is challenging as it relies on the color difference between blanched and perfused skin. We proposed a new method of negative pressure-induced hyperemia (NPIH) using handheld electrical negative pressure devices to improve flap monitoring.

METHODS

Forty consecutive patients who received 42 free flaps in our institution were included in the study. Postoperatively, digital photographs were taken during CRT and NPIH, and the color difference (ΔE) was calculated based on the images. Additionally, three surgeons and three nurses evaluated the ease of assessment of capillary refill and NPIH on each flap using five grades.

RESULTS

NPIH yielded a significantly higher color difference than CRT with a mean ΔE of 10.3 ± 3.3 versus 6.8 ± 4.2. Although for CRT, ΔE of 14 flaps was <5 and of seven flaps <3, all flaps had a ΔE of >5 for NPIH. Subjectively, both surgeons and nurses found NPIH in all flaps to be easier to assess with a mean score of 1.1 ± 0.3 versus 1.8 ± 1.1 for CRT. However, some flaps were found to be challenging or not assessable by CRT.

CONCLUSION

NPIH represents a safe, easily applicable, and cheap addition to the established clinical and technical examination methods and may offer advantages over conventional CRT in detecting arterial complications in pale flaps.

Use of Near-infrared Spectroscopy and Implantable Doppler for Postoperative Monitoring of Free Tissue Transfer for Breast Reconstruction: A Systematic Review and Meta-analysis

BACKGROUND

Failure to accurately assess the perfusion of free tissue transfer (FTT) in the early postoperative period may contribute to failure, which is a source of major patient morbidity and healthcare costs. This systematic review and meta-analysis aim to evaluate and appraise current evidence for the use of near-infrared spectroscopy (NIRS) and/or implantable Doppler (ID) devices compared with conventional clinical assessment (CCA) for postoperative monitoring of FTT in reconstructive breast surgery.

METHODS

A systematic literature search was performed in accordance with the preferred reporting items for systematic reviews guidelines. Studies in human subjects published within the last decade relevant to the review question were identified. Meta-analysis using random-effects models of FTT failure rate and STARD scoring was then performed on the retrieved publications.

RESULTS

Nineteen studies met the inclusions criteria. For NIRS and ID, the mean sensitivity for the detection of FTT failure is 99.36% and 100% respectively, with average specificity of 99.36% and 97.63%, respectively. From studies with sufficient reported data, meta-analysis results demonstrated that both NIRS [OR = 0.09 (0.02-0.36); P < 0.001] and ID [OR = 0.39 (0.27-0.95); P = 0.04] were associated with significant reduction of FTT failure rates compared with CCA.

CONCLUSIONS

The use of ID and NIRS provided equivalent outcomes in detecting FTT failure and were superior to CCA. The ability to acquire continuous objective physiological data regarding tissue perfusion is a perceived advantage of these techniques. Reduced clinical staff workload and minimized hospital costs are also perceived as positive consequences of their use.

Relative Tissue Oxygenation and Temperature Changes for Detecting Early Upper Extremity Skin Ischemia

The authors' purpose was to determine whether there are reliable noninvasive methods of assessing upper extremity ischemia regardless of skin pigmentation. The authors conducted a study of healthy subjects classified based on skin pigmentation using the Fitzpatrick scale, the von Luschan color scale, and self-described race (two Hispanics, three Caucasians, and four African Americans). A surface temperature probe and a near-infrared spectroscopy monitor were placed on the posterior interosseous artery skin territory. Temporary upper limb ischemia was induced by tourniquet insufflation. Readings from both devices were taken at baseline and every 15 seconds for a total of 10 minutes of ischemia. During tourniquet insufflation, the authors found a reliable decrease in tissue oxygenation measured by near-infrared spectroscopy in all subjects and no significant change in temperature readings for any subjects. There was an average decrease of 19 percent in tissue oxygenation using near-infrared spectroscopy, with measurements on average starting at 77 percent and ending at 57 percent. There was no significant difference in the change in near-infrared spectroscopy oxygenation between participants with Fitzpatrick skin types 3, 4, and 5 or when participants were grouped into Fitzpatrick skin type less than or equal to 3 versus greater than 3, or when grouped into Fitzpatrick skin type less than or equal to 4 versus greater than 4. There was also no significant difference in participants grouped into von Luschan scores less than or equal to 20 versus greater than 20. In this healthy subjects study, near-infrared spectroscopy rapidly identified ischemia in all cases, whereas skin surface temperature did not. Near-infrared spectroscopy may be a reliable way of noninvasively monitoring for ischemia regardless of skin pigmentation degree. CLINICAL QUESTION/LEVEL OF EVIDENCE:: Diagnostic, IV.

Enhanced Recovery for Breast Reconstruction Surgery

PURPOSE OF REVIEW

Enhanced recovery pathways are a well-described perioperative healthcare program involving evidence-based interventions. Enhanced recovery is designed to standardize techniques such as drug selection and nerve blocks in order to speed recovery and reduce overall hospital costs.

RECENT FINDINGS

A PubMed literature search was performed for articles that included the terms enhanced recovery and breast reconstruction surgery. The present investigation summarizes enhanced recovery literature related to breast surgery with a focus on breast reconstruction. Enhanced recovery considerations discussed in this review include patient education, preadmission optimization, perforator flap planning, anesthetic techniques, optimized fasting, venous thrombosis prophylaxis, early mobilization, and antimicrobial prophylaxis.

The Effect of Skin Pigmentation on Determination of Limb Ischemia

PURPOSE

Timely identification of tissue ischemia is critical, both in the traumatized limb and following free tissue transfer. The purpose of this study was to determine if skin pigmentation affects the ability to detect limb ischemia.

METHODS

We conducted a study of healthy controls exposed to limb ischemia. The subjects were classified based on skin pigmentation using a defined skin type assessment tool, a visual color scale, and self-description of race. Participants were randomized by limb and tourniquet status; surgeons were blinded to both. Ischemia was induced by tourniquet insufflations, and board-certified orthopedic and plastic surgeons who had completed an accredited hand surgery fellowship conducted physical examinations. The surgeons monitored the forearms at 2, 6, and 10 minutes based on appearance of ischemia, capillary refill, and color in 3 locations on the limbs (posterior interosseous artery flap skin territory, radial forearm flap skin territory, and the digits).

RESULTS

We found a significant decrease in the ability to detect ischemia in participants with increased skin pigmentation, as documented by all metrics, when evaluating the posterior interosseous artery and radial forearm flap skin territories at all time points. For example, when monitoring the posterior interosseous artery flap with the tourniquet insufflated at time 10 minutes, 92.9% of Caucasians were correctly identified as being ischemic whereas only 23.3% of African Americans were correctly identified.

CONCLUSIONS

Skin pigmentation significantly affects the identification of an ischemic limb/skin flaps on physical examination. Whereas the standard treatment for monitoring of free tissue transfer is clinical examination, that may not be sufficient for patients with increased skin pigmentation. Surgeons should exercise particular vigilance during physical examination of a potentially ischemic limb/skin flaps with greater skin pigmentation.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic II.

Consensus Review of Optimal Perioperative Care in Breast Reconstruction: Enhanced Recovery after Surgery (ERAS) Society Recommendations

BACKGROUND

Enhanced recovery following surgery can be achieved through the introduction of evidence-based perioperative maneuvers. This review aims to present a consensus for optimal perioperative management of patients undergoing breast reconstructive surgery and to provide evidence-based recommendations for an enhanced perioperative protocol.

METHODS

A systematic review of meta-analyses, randomized controlled trials, and large prospective cohorts was conducted for each protocol element. Smaller prospective cohorts and retrospective cohorts were considered only when higher level evidence was unavailable. The available literature was graded by an international panel of experts in breast reconstructive surgery and used to form consensus recommendations for each topic. Each recommendation was graded following a consensus discussion among the expert panel. Development of these recommendations was endorsed by the Enhanced Recovery after Surgery Society.

RESULTS

High-quality randomized controlled trial data in patients undergoing breast reconstruction informed some of the recommendations; however, for most items, data from lower level studies in the population of interest were considered along with extrapolated data from high-quality studies in non-breast reconstruction populations. Recommendations were developed for a total of 18 unique enhanced recovery after surgery items and are discussed in the article. Key recommendations support use of opioid-sparing perioperative medications, minimal preoperative fasting and early feeding, use of anesthetic techniques that decrease postoperative nausea and vomiting and pain, use of measures to prevent intraoperative hypothermia, and support of early mobilization after surgery.

CONCLUSION

Based on the best available evidence for each topic, a consensus review of optimal perioperative care for patients undergoing breast reconstruction is presented.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, V.

The unsuitability of implantable Doppler probes for the early detection of renal vascular complications - a porcine model for prevention of renal transplant loss

BACKGROUND

Vascular occlusion is a rare, but serious complication after kidney transplantation often resulting in graft loss. We therefore aimed to develop an experimental porcine model for stepwise reduction of the renal venous blood flow and to compare an implantable Doppler probe and microdialysis for fast detection of vascular occlusion.

METHODS

In 20 pigs, implantable Doppler probes were placed on the renal artery and vein and a microdialysis catheter was placed in the renal cortex. An arterial flowprobe served as gold standard. Following two-hour baseline measurements, the pigs were randomised to stepwise venous occlusion, complete venous occlusion, complete arterial occlusion or controls.

RESULTS

All parameters were stable through baseline measurements. Glutamate and lactate measured by microdialysis increased significantly (p = 0.02 and p = 0.03 respectively) 30 minutes after a 2/3 (66%) reduction in renal blood flow. The implantable Doppler probe was not able to detect flow changes until there was total venous occlusion. Microdialysis detected changes in local metabolism after both arterial and venous occlusion; the implantable Doppler probe could only detect vascular occlusions on the vessel it was placed.

CONCLUSIONS

We developed a new model for stepwise renal venous blood flow occlusion. Furthermore, the first comparison of the implantable Doppler probe and microdialysis for detection of renal vascular occlusions was made. The implantable Doppler probe could only detect flow changes after a complete occlusion, whereas microdialysis detected changes earlier, and could detect both arterial and venous occlusion. Based on these results, the implantable Doppler probe for early detection of vascular occlusions cannot be recommended.

Implantable Doppler Probes for Postoperatively Monitoring Free Flaps: Efficacy. A Systematic Review and Meta-analysis

Background:

Although clinical assessment remains the gold standard for monitoring the circulation of free flaps, several adjunct techniques promote timely salvage by detecting circulation compromise early. The objective of this systematic review was to evaluate the efficacy of an implantable Doppler probe for postoperatively monitoring free flaps.

Materials and Methods:

English-language articles evaluating the efficacy of implantable Doppler probes compared with clinical assessment for postoperatively monitoring free flaps were analyzed. The outcome measures were total flap failure rates, salvage rates, sensitivity, false-positive rates, and positive likelihood ratios.

Results:

Of the 504 citations identified, 6 comparative studies were included for meta-analysis. An implantable Doppler probe significantly lowered the flap failure rate (risk ratio: 0.40; 95% confidence interval: 0.21–0.75) and raised the successful salvage rate (risk ratio: 1.73; 95% confidence interval: 1.16–2.59). Pooled sensitivity was higher (1.00 vs 0.98), the positive likelihood ratio was lower (72.16 vs 220.48), and the false-positive rate was higher (0.01 vs 0) in the implantable Doppler probe group than in the clinical assessment group.

Conclusion:

An implantable Doppler probe is significantly more efficacious than clinical assessment for postoperatively monitoring free flaps.

A comparison of the Cook-Swartz Doppler with conventional clinical methods for free flap monitoring: A systematic review and a meta-analysis

INTRODUCTION

Currently there is no consensus on what is the optimal method for monitoring free flaps. Our meta-analysis compared the free flap success and salvage rates of Cook-Swartz Implantable Doppler monitoring with clinical monitoring to gain insight into the relative benefit of these systems.

METHODS

Medline, Cochrane, EMBASE, and Google Scholar databases were searched until January 16, 2016. Search terms included free flap surgery, free flap microsurgery and implantable Doppler. Studies were included if they involved the comparison of Cook-Swartz Doppler and clinical assessment for monitoring free flap function. Studies using free flap monitoring as an outcome measure for drug treatment were also excluded. Sensitivity analysis using the leave-one-out approach was used to assay the reliability of the findings.

RESULTS

Initial search identified 14 studies, of which five studies were included in the meta-analysis. Cook-Swartz Doppler had significantly better rate of free flap success and salvage than clinical monitoring methods (P values ≤ 0.006). Data did not markedly changed when each study was removed in turn, showing reliability of the findings.

DISCUSSION

The Cook-Swartz Doppler as a monitoring method may result in a higher rate of free flap success and salvaging but also a greater frequency of false positives than conventional methods. Our analysis is limited by designs of included studies and by heterogeneity of clinical monitoring techniques.

CONCLUSIONS

More studies are needed to evaluate if Cook-Swartz Doppler can be used alone, or to be better used as an adjunctive technique to complement the clinical method of monitoring.

Postoperative monitoring of free flap reconstruction: A comparison of external Doppler ultrasonography and the implantable Doppler probe

HYPOTHESIS

The time to detection of vascular compromise and the postoperative time to re-exploration are shorter using the implantable Doppler (ID) probe, thereby resulting in earlier surgical re-exploration and a higher flap salvage rate.

METHODS

A single-centre experience with 176 consecutive free flap reconstructions in 167 patients from 2000 to 2008 in a university-based teaching hospital by retrospective chart review is presented.

RESULTS

There was a significant difference in overall flap survival (ID 98.0%, external Doppler [ED] 89.3%) and total flap loss (ID 2.0%, ED 10.7%) between the two groups (P=0.03). The difference in flap salvage rate was not significant (ID 90.9%, ED 63.6%; P=0.068). The false-positive (ID 0%, ED 3%; P=0.18) and false-negative rates (ID 0.0%, ED 4.5%; P=1.0) were not significantly different. There was also a lower median postoperative time to re-exploration for the ID group, from 48 h to one week after initial surgery (ID 74.5 h, ED 136.8 h; P=0.05).

CONCLUSION

The present analysis revealed a potential benefit for the ID probe in the postoperative monitoring of free tissue transfers.

Postoperative monitoring of free flap reconstruction: A comparison of external Doppler ultrasonography and the implantable Doppler probe

Hypothesis

The time to detection of vascular compromise and the postoperative time to reexploration are shorter using the implantable Doppler (ID) probe, thereby resulting in earlier surgical reexploration and a higher flap salvage rate.

Methods

A single-centre experience with 176 consecutive free flap reconstructions in 167 patients from 2000 to 2008 in a university-based teaching hospital by retrospective chart review is presented.

Results

There was a significant difference in overall flap survival (ID 98.0%, external Doppler [ED] 89.3%) and total flap loss (ID 2.0%, ED 10.7%) between the two groups (P=0.03). The difference in flap salvage rate was not significant (ID 90.9%, ED 63.6%; P=0.068). The false-positive (ID 0%, ED 3%; P=0.18) and false-negative rates (ID 0.0%, ED 4.5%; P=1.0) were not significantly different. There was also a lower median postoperative time to reexploration for the ID group, from 48 h to one week after initial surgery (ID 74.5 h, ED 136.8 h; P=0.05).

Conclusion

The present analysis revealed a potential benefit for the ID probe in the postoperative monitoring of free tissue transfers.

The venous anatomy of the abdominal wall for Deep Inferior Epigastric Artery (DIEP) flaps in breast reconstruction

BACKGROUND

Despite improving outcomes, venous problems in the harvest of deep inferior epigastric artery perforator (DIEP) flaps remain the more common vascular complications. However, it is apparent that the venous anatomy of the anterior abdominal wall has not been described to the same extent as the arterial anatomy. Cadaveric dissection studies of venous anatomy frequently lack the detail of their arterial counterparts. Venous valves complicate retrograde injection, resulting in poor quality studies with limited anatomical information.

METHODS

The current manuscript comprises a review of the literature, highlighting key features of the anatomy of the venous drainage of the abdominal wall integument, with particular pertinence to DIEP flaps. Both cadaveric and clinical studies are included in this review. Our own cadaveric and in-vivo studies were undertaken and included in detail in this manuscript, with the cadaveric component utilizing direct catheter venography and the in-vivo studies were undertaken using preoperative computed tomographic angiography (CTA), mapping in-vivo venous flow.

RESULTS

Several key features of the venous anatomy of the abdominal wall render it different to other regions, and are of particular importance to DIEP flap transfer.

CONCLUSIONS

The cause of venous compromise is multi-factorial, with perforator diameter, midline crossover, and deep-superficial venous communications all important. Venous cadaveric studies as well as clinical CTA preoperatively can identify these anomalies.

A review of devices used in the monitoring of microvascular free tissue transfers

The use of microvascular anastomoses to allow transfer of viable tissue is a fundamental technique of reconstructive surgery, and is used to treat a broad spectrum of clinical problems. The primary threat to this type of reconstructive surgery is anastomotic vascular thrombosis, which can lead to complete loss of tissue with potentially devastating consequences. Monitoring of tissue perfusion postoperatively is critical, since early recognition of vascular compromise and prompt surgical intervention is correlated with the ability for tissue salvage. Traditionally, physical examination was the primary means of monitoring, but possesses several limitations. Medical devices introduced for the purposes of flap monitoring address many of these deficiencies, and have greatly enhanced this critical aspect of the reconstructive surgery process.

Online rapid sampling microdialysis (rsMD) using enzyme-based electroanalysis for dynamic detection of ischaemia during free flap reconstructive surgery

We describe an enzyme-based electroanalysis system for real-time analysis of a clinical microdialysis sampling stream during surgery. Free flap tissue transfer is used widely in reconstructive surgery after resection of tumours or in other situations such as following major trauma. However, there is a risk of flap failure, due to thrombosis in the flap pedicle, leading to tissue ischaemia. Conventional clinical assessment is particularly difficult in such ‘buried’ flaps where access to the tissue is limited. Rapid sampling microdialysis (rsMD) is an enzyme-based electrochemical detection method, which is particularly suited to monitoring metabolism. This online flow injection system analyses a dialysate flow stream from an implanted microdialysis probe every 30 s for levels of glucose and lactate. Here, we report its first use in the monitoring of free flap reconstructive surgery, from flap detachment to re-vascularisation and overnight in the intensive care unit. The on-set of ischaemia by both arterial clamping and failure of venous drainage was seen as an increase in lactate and decrease in glucose levels. Glucose levels returned to normal within 10 min of successful arterial anastomosis, whilst lactate took longer to clear. The use of the lactate/glucose ratio provides a clear predictor of ischaemia on-set and subsequent recovery, as it is insensitive to changes in blood flow such as those caused by topical vasodilators, like papaverine. The use of storage tubing to preserve the time course of dialysate, when technical difficulties arise, until offline analysis can occur, is also shown. The potential use of rsMD in free flap surgery and tissue monitoring is highly promising.

Figure

Implantable Doppler in monitoring free flaps: a cost-effectiveness analysis based on a systematic review of the literature

OBJECTIVE

The purpose of this paper is to evaluate the efficacy and cost-effectiveness of the implantable Doppler system based on the analysis of the available scientific literature and clinical and cost data available in our hospital. The results of this system are compared to those of conventional free flap monitoring methods.

MATERIALS AND METHODS

The literature published between 1991 and 2011 was systematically reviewed. All available cost data were collected and several simulations were performed. A retrospective assessment of the efficacy of conventional methods in our hospital was also conducted.

RESULTS AND CONCLUSION

The implantable Doppler system is more effective than the conventional methods used to monitor free flap perfusion. The mean flap salvage rate with the implantable Doppler was 21 percentage points higher (81.4 vs. 60.4). The excess cost compared to conventional methods was about CAD 120 per patient (about EUR 94). However, this excess cost can be compensated or even reversed, depending on the initial flap salvage rate in the health facility and the type of free flap (buried vs. non-buried).

Current indications for and comparative analysis of three different types of latissimus dorsi flaps

BACKGROUND

Free tissue transfer with lower abdominal flaps for autologous breast reconstruction is not suitable for all patients. The latissimus dorsi (LD) musculocutaneous flap is an alternative, effective method for both immediate and delayed breast reconstruction.

OBJECTIVES

The authors assess their experience with LD flaps for breast reconstruction, including indications for patient selection, donor site choice, aesthetic outcomes, complications, and patient satisfaction.

METHODS

Charts for all patients who underwent breast reconstruction with one of three types of LD myocutaneous flaps during a three-year period at a single institution were retrospectively reviewed. Patients (n = 82) were divided into three groups: (1) 35 patients received a standard LD myocutaneous flap with implant, (2) 18 patients underwent a muscle sparing LD flap procedure with implant, and (3) 29 patients had an autologous LD flap. A questionnaire was administered to assess flap and donor site complications, aesthetic outcomes, patient satisfaction, and shoulder function.

RESULTS

Flap complications occurred in 13 patients (15%). Donor site complications occurred in 24 patients (28%), mostly consisting of back seroma with the autologous LD flap. There was no significant difference in shoulder range of motion or muscle strength between the operated and unoperated sides. Patient satisfaction was high in all three study groups.

CONCLUSIONS

The LD is a safe, versatile, and reproducible technique for breast reconstruction. The procedure benefits from ease of flap harvesting and setting and may provide satisfactory results in diverse patients, including those for whom an abdominal flap is neither indicated nor feasible. .