Differential Photosensitivity of Fibroblasts Obtained from Normal Skin and Hypertrophic Scar Tissues.

It is unclear whether normal human skin tissue or abnormal scarring are photoreceptive. Therefore, this study investigated photosensitivity in normal skin tissue and hypertrophic scars. The expression of opsins, which are photoreceptor proteins, in normal dermal fibroblasts (NDFs) and hypertrophic scar fibroblasts (HSFs) was examined. After exposure to blue light (BL), changes in the expression levels of αSMA and clock-related genes, specifically PER2 and BMAL1, were examined in both fibroblast types. Opsins were expressed in both fibroblast types, with OPN3 exhibiting the highest expression levels. After peripheral circadian rhythm disruption, BL induced rhythm formation in NDFs. In contrast, although HSFs showed changes in clock-related gene expression levels, no distinct rhythm formation was observed. The expression level of αSMA was significantly higher in HSFs and decreased to the same level as that in NDFs upon BL exposure. When OPN3 knocked-down HSFs were exposed to BL, the reduction in αSMA expression was inhibited. This study showed that BL exposure directly triggers peripheral circadian synchronization in NDFs but not in HSFs. OPN3-mediated BL exposure inhibited HSFs. Although the current results did not elucidate the relationship between peripheral circadian rhythms and hypertrophic scars, they show that BL can be applied for the prevention and treatment of hypertrophic scars and keloids.

Early Predictors of Fistula Formation Following Head and Neck Reconstruction.

BACKGROUND: Salivary fistula formation is a common and serious complication following head and neck reconstruction. Because it can cause delayed wound healing and infection and carotid artery rupture in severe cases, hence, early detection and treatment are crucial. This study was designed to identify early predictors of postoperative fistula formation. METHODS: We conducted a retrospective analysis of patients who underwent head and neck reconstruction between 2015 and 2022. Body temperature, serum white blood cell (WBC) count, and serum C-reactive protein (CRP) levels were assessed until postoperative day (POD) 14 and compared between patients with and without fistula. RESULTS: In this study, 200 patients were included. No significant differences in body temperature and WBC count were observed between the two groups during the entire study period. CRP levels after POD2 were higher in the fistula group than in the without fistula group. From the receiver operating characteristic curves comparing the two groups, the best cutoff level for CRP was 6.27 mg/dL from POD7 to POD8, with 77.1% sensitivity, 69.8% specificity, and 90.1% negative predictive value. CONCLUSION: CRP is a valuable predictor of fistula formation following head and neck reconstruction. The course of CRP levels in patients with fistulas remains consistently elevated compared to patients without fistulas, and it is particularly useful for the exclusion diagnosis of fistula.

A Clinical Study of Histopathological and Clinical Image Changes After Sclerotherapy of Lip Venous Malformations.

Venous malformations (VMs) are histopathologically benign but can greatly impair patients' quality of life. Screlothprapy is known to be effective in improving symptoms without a scar, but surgical resection of residual lesions is sometimes necessary due to inadequate reduction. However, there is no consensus on what criteria should be used to consider switching to surgical treatment, and individualized decisions must be made for each case. To investigate the factors that contribute to the lack of efficacy of sclerotherapy in reducing lesions and how to predict this, the authors performed a retrospective clinical imaging and histopathological study of 6 cases of labial vein malformations treated with sclerotherapy and 3 cases without sclerotherapy. Clinical image investigations are based on magnetic resonance imaging before and after sclerotherapy. The authors found a significant decrease in the percentage of cystic components in the total lesion of VMs after sclerotherapy. Histopathological investigations are based on resected VMs with or without sclerotherapy. Elastica van Gieson stains suggested a significant increase in fibrotic tissue inside VMs treated with sclerotherapy compared with those without. In conclusion, magnetic resonance imaging signal changes inside the VMs after sclerotherapy was observed, and it may reflect fibrosis of the tissue. These changes in the VMs after sclerotherapy may reduce the effect of sclerotherapy on tissue reduction should be considered.

Vasodilating Effects of Antispasmodic Agents and Their Cytotoxicity in Vascular Smooth Muscle Cells and Endothelial Cells-Potential Application in Microsurgery.

This study aimed to elucidate the vasodilatory effects and cytotoxicity of various vasodilators used as antispasmodic agents during microsurgical anastomosis. Rat smooth muscle cells (RSMCs) and human coronary artery endothelial cells (HCAECs) were used to investigate the physiological concentrations and cytotoxicity of various vasodilators (lidocaine, papaverine, nitroglycerin, phentolamine, and orciprenaline). Using a wire myograph system, we determined the vasodilatory effects of each drug in rat abdominal aortic sections at the concentration resulting in maximal vasodilation as well as at the surrounding concentrations 10 min after administration. Maximal vasodilation effect 10 min after administration was achieved at the following concentrations: lidocaine, 35 mM; papaverine, 0.18 mM; nitroglycerin, 0.022 mM; phentolamine, 0.11 mM; olprinone, 0.004 mM. The IC50 for lidocaine, papaverine, and nitroglycerin was measured in rat abdominal aortic sections, as well as in RSMCs after 30 min and in HCAECs after 10 min. Phentolamine and olprinone showed no cytotoxicity towards RSMCs or HCAECs. The concentrations of the various drugs required to achieve vasodilation were lower than the reported clinical concentrations. Lidocaine, papaverine, and nitroglycerin showed cytotoxicity, even at lower concentrations than those reported clinically. Phentolamine and olprinone show antispasmodic effects without cytotoxicity, making them useful candidates for local administration as antispasmodics.

Analysis of Orbital Blowout Fracture Location and Hess Area Ratio.

ABSTRACT: This study aimed to analyze the Hess area ratio (HAR%) in cases of blowout fracture treated in our department and clarify the outline of eye movement disorders in blowout fractures. Patients who underwent surgery for orbital blowout fractures in our department were included. Fracture locations were classified into 5 types (A, outside floor; B, C, anterior and posterior floor; and D, E, anterior and posterior medial wall). The HAR% was compared before and after surgery in eligible cases. The relationship between the fracture location and preoperative HAR% was investigated using multiple regression analysis. The study involved 85 patients. Hess area ratio was higher postoperatively than preoperatively (70.75 ±â€Š18.26 versus 90.06 ±â€Š13.99, P  < 0.01). The postoperative HAR% tended to be higher when the iliac bones were compared to other materials; however, this difference was not significant (90.73 ±â€Š12.91 versus 80.30 ±â€Š17.81, P = 0.178). Fracture locations C and E significantly contributed to the prediction of HAR% as negative regression coefficients (P = 0.024 and 0.013, respectively). The posterior fracture area on both the orbital floor and medial wall contributed to the decrease in preoperative HAR%. This observation indicates that the reconstruction of the posterior region is extremely crucial.

OPN4 belongs to the photosensitive system of the human skin.

The human skin has previously been described to be affected by light; however, the underlying mechanism remains unknown. OPN4 (melanopsin) expression was first identified in the skin of amphibians; however, whether it is also expressed and functioned in the human skin has not yet been identified. Here, we show that OPN4 was expressed in the human skin tissue and cultures of isolated keratinocytes, melanocytes and fibroblasts. Additionally, Ca2+ influx in vitro and ex vivo and phosphorylation of extracellular signal-regulated kinases 1/2 in human fibroblasts were observed by stimulation of blue light irradiation. Notably, our findings showed that this Ca2+ influx and phosphorylation of extracellular signal-regulated kinases 1/2 are promoted in an intensity-dependent manner, indicating that the light signal is converted to an intracellular signal via OPN4 in the human skin. Overall, in this study we showed that the human skin functions as a photoreceptor by demonstrating that in human skin, the photoreceptive protein was expressed, and photoreception was conducted via photoreceptive protein.

Wire Myography for Continuous Estimation of the Optimal Concentration of Topical Lidocaine as a Vasodilator in Microsurgery.

BACKGROUND: Intraoperative vasospasm during reconstructive microvascular surgery is often unpredictable and may lead to devastating flap loss. Therefore, various vasodilators are used in reconstructive microsurgery to prevent and relieve vasospasm. Lidocaine is a vasodilator commonly used in microvascular surgery. Although many reports have described its in vitro and in vivo concentration-dependent vasodilatory effects, limited studies have examined the pharmacological effects of lidocaine on blood vessels in terms of persistence and titer. METHODS: In this study, the vasodilatory effect of lidocaine was examined by using the wire myograph system. Abdominal aortas were harvested from female rats, sliced into rings of 1-mm thickness, and mounted in the wire myograph system. Next, 10, 5, 2, and 1% lidocaine solutions were applied to the artery, and the change in vasodilation force, persistence of the force, and time required to reach equilibrium were measured. RESULTS: The vasodilatory effect was confirmed in all groups following lidocaine treatment. Although strong vasodilation was observed in the 10% lidocaine group, it was accompanied by irreversible degeneration of the artery. Vasodilation in the 1% lidocaine group was weaker than that in the other groups 500 seconds after lidocaine addition (p < 0.05). Between the 5 and 2% lidocaine groups, 5% lidocaine showed a stronger vasodilatory effect 400 to 600 seconds after lidocaine addition (p < 0.01); however, there was no significant difference in these groups after 700 seconds. Additionally, there was no difference in the time required for the relaxation force to reach equilibrium among the 5, 2, and 1% lidocaine groups. CONCLUSION: Although our study confirmed the dose-dependent vasodilatory effect of lidocaine, 5% lidocaine showed the best vasodilatory effect and continuity with minimal irreversible changes in the arterial tissue.

Long-Term Effects on Volume Change in Musculocutaneous Flaps after Head and Neck Reconstruction.

OBJECTIVE: Musculocutaneous flap reconstruction surgery is one of the standard procedures following head and neck cancer resection. However, no previous studies have classified flaps in terms of muscle and fat or examined them after long-term follow-up. The purpose of this study was to estimate the fat and muscle volume changes in musculocutaneous flaps during long-term follow-up. METHODS: We conducted a retrospective analysis of 35 patients after musculocutaneous flap reconstruction. The total, fat, and muscle volumes of the musculocutaneous flaps were measured using 3-dimensional images. Changes in flap volumes over time (1 month, 1 year [POY1], and 5 years [POY5] postoperatively) were assessed. Flap persistence was calculated using flap volumes at 1 month after reconstruction for reference. RESULTS: Flap persistence at POY5 was 42.0% in total, 64.1% in fat, and 25.4% in muscle. Muscle persistence was significantly decreased (p < 0.0001). In a multiple regression analysis, decreased body mass index (BMI) of ≥ 5% influenced fat persistence less than muscle persistence at POY1; however, there was no significant difference at POY5. Postoperative radiation therapy was associated with a significant decrease in total flap persistence at POY1 (p = 0.046) and POY5 (p = 0.0097). Muscle persistence significantly decreased at POY5 (p = 0.0108). Age significantly influenced muscle volume at POY1 (p = 0.0072). CONCLUSION: Reconstruction flaps are well-preserved with high fat-to-muscle ratios. Recommendations for weight maintenance are necessary for patients less than 2 years after surgery due to the influence of BMI on fat persistence. Radiation therapy is necessary for some patients based on their disease state. Intensity-modulated radiation therapy can be offered to reduce scattering irradiation to normal tissues.

Does salivary duct repositioning prevent complications after tumor resection or salivary gland surgery?

PURPOSE: Tissue that is resected for the treatment of oral tumors often includes salivary gland ducts. At their institution, the authors conserve and transfer as much of the salivary duct as possible during these procedures to avoid obstructive complications. Differentiating these obstructive complications from a metastatic node can be challenging and can confound subsequent oncologic management. This study compared and examined the effectiveness of salivary duct repositioning in decreasing the incidence of obstructive complications. MATERIALS AND METHODS: Cases of oromandibular disease treated with salivary duct resection at Kobe University Graduate School of Medicine from 2008 to 2013 were retrospectively analyzed. Thirty-two cases (25 patients) of Wharton duct resection and 31 cases (31 patients) of Stensen duct resection were included. The incidence of complications after salivary duct repositioning, duct ligation, and retention of the sublingual gland around the Wharton duct was compared. RESULTS: Wharton ducts were repositioned in 30 cases and ligated in 2 cases. Complications, including oral swelling at the Wharton duct, were observed in 5 cases of repositioning and 2 cases of ligation. Stensen ducts were repositioned in 9 cases and ligated in 22 cases. The only complication reported was a single case of salivary fistula after ligation. CONCLUSIONS: Salivary duct repositioning is performed to prevent blockage of physiologic salivary discharge. Complications were more frequently associated with Wharton ducts than with Stensen ducts because of the unique physiologic and anatomic characteristics of the Wharton duct. Repositioning of the salivary duct is a suitable method for preventing complications associated with the Wharton duct.

Three-dimensional venous visualization with phase-lag computed tomography angiography for reconstructive microsurgery.

BACKGROUND: Most free flap reconstruction complications involve vascular compromise. Evaluation of vascular anatomy provides considerable information that can potentially minimize these complications. Previous reports have shown that contrast-enhanced computed tomography is effective for understanding three-dimensional arterial anatomy. However, most vascular complications result from venous thromboses, making imaging of venous anatomy highly desirable. METHODS: The phase-lag computed tomography angiography (pl-CTA) technique involves 64-channel (virtually, 128-channel) multidetector CT and is used to acquire arterial images using conventional CTA. Venous images are three-dimensionally reconstructed using a subtraction technique involving combined venous phase and arterial phase images, using a computer workstation. RESULTS: This technique was used to examine 48 patients (12 lower leg reconstructions, 34 head and neck reconstructions, and 2 upper extremity reconstructions) without complications. The pl-CTA technique can be used for three-dimensional visualization of peripheral veins measuring approximately 1 mm in diameter. CONCLUSION: The pl-CTA information was especially helpful for secondary free flap reconstructions in the head and neck region after malignant tumor recurrence. In such cases, radical dissection of the neck was performed as part of the first operation, and many vessels, including veins, were resected and used in the first free-tissue transfer. The pl-CTA images also allowed visualization of varicose changes in the lower leg region and helped us avoid selecting those vessels for anastomosis. Thus, the pl-CTA-derived venous anatomy information was useful for exact evaluations during the planning of free-tissue transfers.

Intima/medulla reconstruction and vascular contraction-relaxation recovery for acellular small diameter vessels prepared by hyperosmotic electrolyte solution treatment.

This study aims at the evaluation of blood vessel reconstruction process of decellularized small diameter vessels prepared by a hyperosmotic electrolyte solution treatment not only histologically but also physiologically in rat transplantation model. Complete cell removal by a hyperosmotic electrolyte solution treatment was confirmed by hematoxylin/eosin staining and scanning electron microscopic observation. All acellular vessels transplanted into the rat abdominal aorta were patent up to 14 months. One week post-transplantation, the vWF-positive cells were observed on the luminal surface but the layer formation did not complete. Five weeks following transplantation, the vWF-positive endothelial cells were located on the intima consistent with intact endothelial cells. Beneath the endothelial cells, α-SMA-positive smooth muscle cells were distributed. The harvested vessels displayed formation of tunica intima (endothelial cells) and tunica medulla (smooth muscle cell) layers. We also examined the physiological properties of the vessels 12 months post-transplantation using a wire myograph system. The transplanted vessels contracted upon addition of norepinephrine and relaxed upon addition of sodium nitroprusside as well as the native vessels. In conclusion, the acellular vessels prepared with hyperosmotic electrolytic solution showed excellent and long-term patency, which may be related to the successful preservation of vascular ECM. In addition, the acellular vessels revealed the intima/medulla regeneration with the physiological contraction-relaxation functions in response to the each substance.

Polypropylene Mesh Infection From Surgical Site Infections Caused by Mycobacterium fortuitum.

This report highlights two cases of surgical site infections (SSIs) caused by Mycobacterium fortuitum (Mf) following abdominal mesh implantation. The first case involved an 83-year-old male experiencing non-healing erythema and wounds post-operation, which persisted despite multiple treatments, until effective management was achieved with targeted antibiotics after Mf identification. The second case concerned a female patient with a gynecological postoperative hernia, where Mf was quickly detected following SSI onset three weeks after surgery. Prompt mesh removal and appropriate antibiotic treatment led to a rapid and full recovery. These cases emphasize the importance of early detection and intervention in managing Mf infections effectively, illustrating how the timing of diagnosis can significantly influence treatment outcomes.

Comparison of malignant skin tumor thickness and relative depth of invasion estimates from preoperative MR-microscopy and pathological evaluation.

BACKGROUND: Tumor thickness and relative depth of invasion are prognostic parameters considered when developing treatment plans for malignant skin tumors. Although conventional magnetic resonance (MR) imaging techniques cannot identify small tumors, use of microscopy coils considerably improves spatial resolution. Some studies have shown that this technique is efficacious in preoperative assessment of relative depth of invasion; however, its ability to provide accurate measurements of tumor thickness remains unconfirmed. OBJECTIVE: The purpose of this pilot study was to evaluate the usefulness of preoperative MR-microscopy in determining tumor thickness and relative depth of invasion of malignant skin tumors. METHODS AND MATERIALS: Magnetic resonance images of malignant skin tumors in seven female patients (six with basal cell carcinoma and one with malignant melanoma) were obtained using a 1.5 T system and a 47-mm or 23-mm microscopy coil. Tumors were then excised, fixed, dehydrated, embedded, and stained with hematoxylin and eosin. We then compared MR-microscopy and pathology values for thickness and relative depth of invasion of each tumor. RESULTS: Both techniques produced similar measurements of tumor thickness and relative depth of invasion. CONCLUSIONS: MR-microscopy is very useful for accurate preoperative estimation of not only relative depth of invasion, but also thickness of malignant skin tumors.

One-stage umbilicus reconstruction after resection of urachal cyst.

Umbilical reconstruction after total excision of the umbilicus represents a challenging problem for reconstructive surgeons. We describe herein a new method for one-stage umbilical reconstruction after resection of a urachal cyst. This case series included 6 patients, with laparoscopic urachal cyst removal in 5 and conventional transcutaneous surgery in 1. One-stage umbilical reconstruction was performed in all cases. When a conventional transcutaneous approach is indicated, umbilical reconstruction can be undertaken through the same skin incision used for total resection of the urachal cyst. Two triangular flaps were designed just below the umbilical defect. Flaps were rotated 180 degrees and sutured together to form one big triangular flap. This flap was then folded to create the new umbilicus. A deep umbilicus with good shape was constructed in all cases, and all patients were satisfied with the outcome. This method is simple, easy, and produces a natural-looking umbilicus.

Preoperative MR angiography for free fibula osteocutaneous flap transfer.

INTRODUCTION: Magnetic resonance angiography (MRA) is currently considered the most useful test to evaluate the vascular anatomy of the lower leg prior to free fibula osteocutaneous flap transfer. This study aimed to confirm the validity of preoperative MRA. METHODS: In 19 patients underwent free fibula osteocutaneous flap transfer for maxillary and mandibular reconstruction, the MRA and intraoperative findings and the postoperative complications were retrospectively analyzed. The location and number of distal septocutaneous perforators (dSCPs) that were preoperatively identified and harvested with flaps were documented. RESULTS: Preoperative MRA detected dSCPs with 100% sensitivity. MRA findings also revealed the diversity of vascular structures, such as the tibio-peroneal bifurcation location and the anatomical relationship between the peroneal vessels and the fibula. No patients suffered postoperative ischemic complications in the donor leg. The total flap survival rate was 95 %. CONCLUSIONS: Preoperative MRA effectively excluded large vessel anomalies and peripheral vascular disease, and precisely identified the septocutaneous perforators. Additionally, preoperative MRA contributed to a safer fibular osteotomy by predicting the anatomical relationship between the peroneal vessels and the fibula.

Absorbable Barbed Continuous versus Nonabsorbable Nonbarbed Interrupted Suturing Methods for Donor-site Closure of the Rectus Abdominis Myocutaneous Flap.

Abdominal incisional hernia is a complication of the rectus abdominis myocutaneous (RAMC) flap harvest. This study aimed to compare the incidence of abdominal incisional hernia and donor-site closure time between absorbable barbed continuous (ABC) and non-absorbable non-barbed interrupted (nAnBI) methods. Methods: This study included 145 patients who underwent free RAMC flap reconstruction after head and neck cancer surgery at Kobe University Hospital between January 2012 and March 2020. The nAnBI method was selected between January 2012 and August 2016, and the ABC method was selected between September 2016 and March 2020. The incidence of abdominal incisional hernia and the average time required for donor-site closure were compared between the two groups. Results: Of the 145 patients surveyed, 116 (57 and 59 in the nAnBI and ABC groups, respectively) were followed-up for at least 90 days after the surgery. The incidence rates of abdominal incisional hernia were 0% and 5.1% (n = 3) in the nAnBI and ABC groups, respectively, with no significant differences (p = 0.244). The average donor-site closure times were 127.6 and 111.3 minutes in the nAnBI and ABC groups, respectively, with no significant differences (p = 0.122). Conclusions: No significant differences in the incidence of abdominal incisional hernia and donor-site closure time were observed between the nAnBI and ABC groups. However, there was a tendency for increased hernia occurrence and shorter wound closure time in the ABC group. A randomized prospective multicenter study is warranted to validate our findings of the ABC method.

The superficial branch of the radial nerve and sensory disturbance in the radial forearm flap donor-site.

Introduction: Sensory disturbance due to injury of the superficial branch of the radial nerve (SBRN) is a donor-site morbidity of the radial forearm (RF) flap. The relationship between the SBRN preservation method and the post-operative sensation at the flap donor-site was retrospectively investigated. Methods: We included 39 patients who underwent head and neck reconstruction with a free RF flap at Hyogo Cancer Center between April 2014 and March 2018. The patients were classified into the following three groups according to the SBRN preservation method: group 1, zero preservation, excision of the entire SBRN; group 2, main trunk preservation, excision of all branches except the main trunk of the SBRN; and group 3, complete preservation, preservation of the entire SBRN. Objective sensations and subjective symptoms at the flap donor-site were analyzed. Results: The mean objective sensory scores were 3.18, 2.97, and 1.78 in groups 1, 2, and 3, respectively. Differences between groups 1 and 3 and between groups 2 and 3 were significant (p = 0.0035 and p = 0.037, respectively). The mean subjective symptom scores were 2.40, 1.33, and 1.40 in groups 1, 2, and 3, respectively. Differences between groups 1 and 2, and between groups 1 and 3 were significant (p = 0.032 and p = 0.019, respectively). Conclusions: Zero preservation method had a higher risk of subjective symptoms and objective hypoesthesia development at the flap donor-site than the complete preservation method. Despite inevitable objective hypoesthesia, the main trunk preservation prevented the development of subjective symptoms. Complete preservation is optimal for RF flap harvest; however, in case of perforator crossing, main trunk preservation is another option.

Construction and Validation of an Image Discrimination Algorithm to Discriminate Necrosis from Wounds in Pressure Ulcers.

Artificial intelligence (AI) in medical care can raise diagnosis accuracy and improve its uniformity. This study developed a diagnostic imaging system for chronic wounds that can be used in medically underpopulated areas. The image identification algorithm searches for patterns and makes decisions based on information obtained from pixels rather than images. Images of 50 patients with pressure sores treated at Kobe University Hospital were examined. The algorithm determined the presence of necrosis with a significant difference (p = 3.39 × 10-5). A threshold value was created with a luminance difference of 50 for the group with necrosis of 5% or more black pixels. In the no-necrosis group with less than 5% black pixels, the threshold value was created with a brightness difference of 100. The "shallow wounds" were distributed below 100, whereas the "deep wounds" were distributed above 100. When the algorithm was applied to 24 images of 23 new cases, there was 100% agreement between the specialist and the algorithm regarding the presence of necrotic tissue and wound depth evaluation. The algorithm identifies the necrotic tissue and wound depth without requiring a large amount of data, making it suitable for application to future AI diagnosis systems for chronic wounds.

Salvage surgery for mesenteric lymph node metastasis by resection of the first jejunal flap and reconstruction with the second jejunal flap.

We report a case of a second free jejunal transfer to treat metastasis in the mesenteric lymph node of the first jejunal flap. A 73-year-old man underwent total pharyngolaryngectomy, bilateral neck dissection, and free jejunal transfer for recurrent hypopharyngeal cancer [left pyriform sinus, pT2N0, moderately differentiated squamous cell carcinoma (SCC)] after radiotherapy. Seven years post-surgery, he underwent transoral videolaryngoscopic surgery for oropharyngeal cancer (soft palate, pT1N0, well-differentiated SCC). Ten years after the first jejunal transfer, metastasis was found in the mesenteric lymph node surrounding the jejunal flap's vascular pedicle. Under general anesthesia, resection of the first jejunum including the affected lymph node, and second jejunal transfer were performed. Lymph node pathological examination revealed poorly differentiated SCC, compatible with pharyngeal cancer metastasis. After neck dissection and jejunal flap transfer, lymphatic collateral pathways toward the flap's mesenteric lymph node might form. Possibly, hypopharyngeal or oropharyngeal cancer metastasized via this pathway.

Simple and Easily Interpretable Flap Monitoring Method Using a Commercial Pulse Oximeter and a Widely Used Bedside Patient Monitor.

Background  Various methods for monitoring after free flap surgery have been reported in the literature. Among them, pulse oximetry shows a sensitive reaction to vascular issues, and it is easy to interpret visually. However, previous reports used special equipment that was less commonly used and difficult to generalize. In this study, we used a commercial pulse oximeter and a widely used bedside patient monitor to monitor transplanted free tissue and lower extremities of healthy subjects with impaired circulation. Methods  A reflectance pulse oximeter sensor was attached on the flap after free tissue transplantation. The sensor was connected to a bedside patient monitor, and the flap oxygen saturation (SpO2) levels and arterial waveforms were continuously monitored. Additionally, blood circulation disorder was induced in the lower limbs of healthy volunteers using pressure cuff inflation on the thigh, and the waveform and SpO2 levels on the pulse oximeter attached to the lower leg were monitored. Results  Twenty-two patients were included in this study. No postoperative vascular issues were observed in any case. Pulse oximeters showed normal rhythmic wavelengths, and the flap SpO2 level ranged approximately >90%. The pulse oximeter waveform rapidly disappeared during arterial occlusion in the thigh pressure cuff inflation test, and the waveform flattened and the SpO2 level decreased slightly during venous congestion. Conclusion  Flap monitoring using a commercially available pulse oximeter and a bedside patient monitor is a versatile, easy-to-interpret, and useful method. Changes in waveform and SpO2 levels appear during arterial and venous circulation disorders, and these changes can be differentiated.