Postoperative Complications of Free Flap Reconstruction in Moderate-Advanced Head and Neck Squamous Cell Carcinoma: A Prospective Cohort Study Based on Real-World Data

Vacuum assisted therapy in the head and neck

PURPOSE OF REVIEW

To review the utility of negative pressure wound therapy (NPWT) in the management of head and neck wounds.

RECENT FINDINGS

NPWT has broad applications in the management of head and neck wounds. NPWT has demonstrated success in the treatment of head and neck fistulas and necrotizing soft tissue infections. Immediate application after free flap reconstruction is also shown to be safe, with benefits of reduced tissue edema and promotion of wound healing. NPWT can further be used to prepare chronic wounds for reconstruction, particularly in patients who have undergone radiotherapy. The addition of intermittent saline instillation and dwell time has shown promise in treating head and neck fistulas.

SUMMARY

NPWT has been shown to improve wound healing times, reduce length of hospital stays, decrease frequency of dressing changes, and lower pain scores compared to conventional wound care. However, existing evidence is largely limited to case reports and retrospective studies, with few prospective comparative studies. Larger prospective studies are needed to further investigate the efficacy and safety of NPWT in the head and neck.

Bone Marrow Mesenchymal Stem Cells-derived Exosomes Promote Survival of Random Flaps in Rats through Nrf2-mediated Antioxidative Stress

BACKGROUND

 Random flaps are the most used defect repair method for head and neck tumors and trauma plastic surgery. The distal part of the flap often undergoes oxidative stress (OS), ultimately leading to flap necrosis. Stem cells' exosomes exhibit potential effects related to anti-inflammatory, regenerative, and antioxidant properties. Nuclear factor erythroid-2-related factor 2 (Nrf2) is an important factor in regulating oxidative balance. Exosomes have been reported to monitor its transcription to alleviate OS. This study examined the impacts and underlying mechanisms of antioxidant actions of exosomes derived from bone marrow mesenchymal stem cells (BMSCs-Exo) on random flaps.

METHODS

 BMSCs-Exo were injected into the tail veins of rats on days 0, 1, and 2 after surgery of random flaps. The rats were euthanized on day 3 to calculate the survival rate. Immunohistochemical staining, western blotting, dihydroethidium probe, superoxide dismutase, and malondialdehyde assay kits were used to detect the OS level. Human umbilical vein endothelial cells were cocultured with BMSCs-Exo and ML385 (an inhibitor of Nrf2) in vitro.

RESULTS

 BMSCs-Exo may significantly improve the survival rate of the random flaps by reducing apoptosis, inflammation, and OS while increasing angiogenesis. Besides, BMSCs-Exo can also increase mitochondrial membrane potential and reduce reactive oxygen species levels in vitro. These therapeutic effects might stem from the activation of the Kelch-like enyol-CoA hydratase (ECH)-associated protein 1 (Keap1)/Nrf2 signaling pathway.

CONCLUSION

 BMSCs-Exo improved the tissue antioxidant capacity by regulating the Keap1/Nrf2 signaling pathway. BMSCs-Exo may be a new strategy to solve the problem of random flap necrosis.

The Freestyle Multiperforator Island Flap: Beyond the Keystone Flap

Background

This study aimed to introduce freestyle multiperforator island flaps as a technical advancement beyond keystone perforator flaps. These flaps represent a fully free-design approach, supplied by multiperforators in small subcutaneous pedicles randomly located, allowing for customized designs tailored to anatomical regions of diverse complexity.

Methods

We present a retrospective cohort study of 150 patients with coverage defects, without distinction of anatomical location or age, treated between 2012 and 2021. The study assessed the clinical presentation, flap characteristics, additional procedures, and postoperative outcomes. We used the chi-square test to assess the relationship between pedicle area size and the incidence of partial or complete necrosis.

Results

We performed 211 flaps on 184 defects, with a mean follow-up of 8.7 months. Tumors (30.4%) and trauma (23.3%) were the most common etiologies. Most flaps were performed on the head and neck (31%) and lower limbs (30.4%). The mean pedicle area was 33%, and the flap-to-defect size ratio was between 1:1 and 3:1 in 82% of cases. Complications occurred in 29.8% of the flaps, with only 8.1% needing surgical reintervention. The most common occurrences were dehiscence (18.5%), partial necrosis (9%), and total necrosis (1.9%). The pedicle area of the flap did not demonstrate a statistically significant relationship with the necrosis outcome (P = 0.813; 95% confidence interval, 0.17-0.926).

Conclusions

Freestyle multiperforator island flaps are a safe and versatile tool with low necrosis rates, excellent aesthetic results, and unmatched cost-effectiveness.

The use of artificial intelligence in reconstructive surgery for head and neck cancer: a systematic review

OBJECTIVES

The popularity of artificial intelligence (AI) in head and neck cancer (HNC) management is increasing, but postoperative complications remain prevalent and are the main factor that impact prognosis after surgery. Hence, recent studies aim to assess new AI models to evaluate their ability to predict free flap complications more effectively than traditional algorithms. This systematic review aims to summarize current evidence on the utilization of AI models to predict complications following reconstructive surgery for HNC.

METHODS

A combination of MeSH terms and keywords was used to cover the following three subjects: "HNC," "artificial intelligence," and "free flap or reconstructive surgery." The electronic literature search was performed in three relevant databases: Medline (Ovid), Embase (Ovid), and Cochrane. Quality appraisal of the included study was conducted using the TRIPOD Statement.

RESULTS

The review included a total of 5 manuscripts (n = 5) for a total of 7524 patients. Across studies, the highest area under the receiver operating characteristic (AUROC) value achieved was 0.824 by the Auto-WEKA model. However, only 20% of reported AUROCs exceeded 0.70. One study concluded that most AI models were comparable or inferior in performance to conventional logistic regression. The highest predictors of complications were flap type, smoking status, tumour location, and age.

DISCUSSION

Some models showed promising results. Predictors identified across studies were different than those found in existing literature, showing the added value of AI models. However, the algorithms showed inconsistent results, underlying the need for better-powered studies with larger databases before clinical implementation.

Postoperative inpatient surgical complications following head and neck microvascular free tissue transfer

BACKGROUND

Complications following head and neck microvascular free tissue transfer (MFTT) are common. Less is known about when they occur.

METHOD

Retrospective study of patients with primary or recurrent head and neck cancer undergoing MFTT reconstruction at a tertiary care institution. MFTT reconstructions with inpatient postoperative complications were included. The Kruskal-Wallis test was used to compare median postoperative day (POD) onset of complication by flap type.

RESULTS

Of 1090 patients undergoing MFTT reconstruction, 126 (11.6%) patients experienced inpatient complications including fibula (n = 35), anterolateral thigh (n = 60), or radial forearm (n = 31) MFTTs. POD onset was shortest for surgical site hematoma (median = 1 [IQR 1-5]), and longest for donor site infection (median = 11.5 [IQR 8-15]). There was no significant difference between flap types and POD onset of complications (p > 0.05).

CONCLUSION

Hematoma formation and flap failure occur earliest during hospitalization, while dehiscence, infection, and fistula occur later. There is no difference in complication timing between flap types.

Dietary nitrate maintains homeostasis of oxidative stress and gut microbiota to promote flap survival in type 2 diabetes mellitus rats

BACKGROUND

Random-pattern skin flaps are commonly used to repair skin tissue defects in surgical tissue reconstruction. However, flap necrosis in the distal area due to ischemia injury is still challenging for its applications in plastic surgery. The complications of diabetes will further increase the risk of infection and necrosis.

METHODS

This study induced type 2 diabetes mellitus (T2DM) rats with a high-fat diet and STZ. The survival rate of the skin flap was observed by adding inorganic sodium nitrate to drinking water. Histology and immunohistochemistry were used to detect the damage to the skin flap. The nitrate content was measured by total nitric oxide and nitrate/nitrite parameter assay. Dihydroethidium and malondialdehyde (MDA) assays were used to value oxidative stress. Rat colon feces were collected for 16s rRNA gene sequence.

RESULTS

Our studies showed that nitrate administration leads to anti-obesity and anti-diabetic effects. Nitrate directly increased the survival area of skin flaps in diabetic rats and mean blood vessel density by enhancing angiogenesis, inhibiting apoptosis, and reducing oxidative stress. The 16s rRNA sequence revealed that nitrate may regulate the homeostasis of the gut microbiota and re-store energy metabolism.

CONCLUSION

Dietary nitrate has been shown to maintain the homeostasis of oxidative stress and gut microbiota to promote flap survival in rats with T2DM.

Incidence and risk factors for postoperative delirium after head and neck cancer surgery: an updated meta-analysis

BACKGROUND

Postoperative delirium (POD) is a frequent neurologic dysfunction that often leads to more negative outcomes. Early identification of patients who are vulnerable to POD and early implementation of appropriate management strategies could decrease its occurrence and improve patient prognosis. Therefore, this meta-analysis comprehensively and quantitatively summarized the prevalence and related predictive factors of POD in head and neck cancer surgical patients.

METHODS

PubMed, Embase, and Cochrane Library were searched for observational studies that reported the prevalence and risk factors for POD after head and neck cancer surgery and were published from their inception until December 31, 2022. Two reviewers independently selected qualified articles and extracted data. The qualities of related papers were assessed using the Newcastle-Ottawa scale (NOS). RevMan 5.3 and Stata 15.0 were applied to analysis the data and conduct the meta-analysis.

RESULTS

Sixteen observational studies with 3289 inpatients who underwent head and neck cancer surgery were included in this review. The occurrence of POD ranged from 4.2 to 36.9%, with a pooled incidence of 20% (95% CI 15-24%, I2 = 93.2%). The results of this pooled analysis demonstrated that the statistically significant risk factors for POD were increased age (OR: 1.05, 95% CI: 1.03-1.07, P < 0.001), age > 75 years (OR: 6.52, 95% CI: 3.07-13.87, P < 0.001), male sex (OR: 2.29, 95% CI: 1.06-4.97, P = 0.04), higher American Society of Anesthesiologists grade (OR: 2.19, 95% CI: 1.44-3.33, P < 0.001), diabetes mellitus (OR: 2.73, 95% CI: 1.24-6.01, P = 0.01), and history of smoking (OR: 2.74, 95% CI: 1.13-6.65, P = 0.03).

CONCLUSIONS

POD frequently occurs after head and neck cancer surgery. Several independent predictors for POD were identified, which might contribute to identifying patients at high risk for POD and play a prominent role in preventing POD in patients following head and neck cancer surgery.

Ovine Forestomach Matrix in the Surgical Management of Complex Volumetric Soft Tissue Defects: A Retrospective Pilot Case Series

Background

Volumetric soft tissue loss is an urgent surgical issue and can frequently lead to suboptimal outcomes for patients due to significant soft tissue loss, compromised vital structures, and contamination. Ovine forestomach matrix (OFM) has demonstrated clinical success in the surgical management of soft tissue defects, especially in contaminated fields, and provides an effective option for immediate coverage of exposed vital structures before definitive closure.

Methods

This retrospective pilot case series (n = 13 defects) evaluated the clinical effectiveness of OFM (graft and/or particulate formats) in the surgical management of contaminated volumetric soft tissue defects. Patients presented with significant soft tissue loss, often with exposed viscera, tendon, bone, or muscle, and were treated with OFM as part of their inpatient surgical management. All patients had at least 1 significant comorbidity with the potential to complicate their healing trajectory. The primary study endpoint was time to 100% granulation tissue coverage (days), and the secondary endpoint was any device-related postoperative complications.

Results

A total of 13 volumetric soft tissue defects were evaluated in 10 patients who underwent surgical reconstruction. Mean defect age was 3.5 ± 5.6 weeks, and mean area was 217.3 ± 77.9 cm2. Most defects had exposed structures (85%), and all defects were Centers for Disease Control and Prevention grade 2 or higher. Mean time to 100% granulation tissue formation was 23.4 ± 9.2 days, with a median product application of 1.0. Staged reconstruction was used in 7 of 13 defects, with the remainder (6 of 13) left to heal via secondary intention using standard wound care protocols. There were no major postoperative infections or adverse events (mean follow-up, 7.4 ± 2.4 weeks.).

Conclusions

This retrospective pilot case series builds on a growing body of evidence that OFM can be utilized to facilitate the formation of functional, well-vascularized soft tissue in large contaminated volumetric soft tissue defects.

Exosomes Derived from Bone Marrow Mesenchymal Stem Cells Alleviate Ischemia-Reperfusion Injury and Promote Survival of Skin Flaps in Rats

Free tissue flap transplantation is a classic and important method for the clinical repair of tissue defects. However, ischemia-reperfusion (IR) injury can affect the success rate of skin flap transplantation. We used a free abdomen flap rat model to explore the protective effects of exosomes derived from bone marrow mesenchymal stem cells (BMSCs-exosomes) against the IR injury of the skin flap. Exosomes were injected through the tail vein and the flaps were observed and obtained on day 7. We observed that BMSCs-exosomes significantly reduced the necrotic lesions of the skin flap. Furthermore, BMSCs-exosomes relieved oxidative stress and reduced the levels of inflammatory factors. Apoptosis was evaluated via the terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay and Western blot analysis of Bax, Bcl-2. Simultaneously, BMSCs-exosomes promoted the formation of new blood vessels in the IR flap, as confirmed by the increased expression level of VEGFA and the fluorescence co-staining of CD31 and PCNA. Additionally, BMSCs-exosomes considerably increased proliferation and migration of human umbilical vein endothelial cells and promoted angiogenesis in vitro. BMSCs-exosomes could be a promising cell-free therapeutic candidate to reduce IR injury and promote the survival of skin flaps.