Reconstruction of the Forehead and Scalp

Application of Free Flaps in Reconstruction of Head and Neck Soft Tissue Defects With Bone Exposure

BACKGROUND

Reconstruction of head and neck soft tissue defects with bone exposure is both challenging and technically demanding for plastic surgeon. Objectives in head and neck soft tissue defects with bone exposure reconstruction are consistent restoration of functionality while also improving appearance. This study retrospectively analyzed the results of head and neck reconstructions using various types of free flaps over the past 4 years.

METHODS

A retrospective analysis was conducted from June 2019 to June 2023 on 12 patients treated at our hospital for head and neck soft tissue defects with bone exposure due to various causes. These included 4 cases of trauma from car accidents, 1 burn case, and 7 postoperative malignant tumor removals. The defect sizes ranged from 4 × 6 to 15 × 45 cm. Different free flaps were used for repair based on the defect, including 6 anterolateral thigh flaps, 3 forearm flaps, 2 latissimus dorsi flaps, and 1 dorsalis pedis flap. Flaps were designed and harvested to match the defect size and transplanted via anastomosed vessels.

RESULTS

All 12 flaps survived successfully. One patient required flap thinning surgery postoperatively. All patients were followed up for over 3 months, showing good color and texture of the transplanted flaps, satisfactory healing, and significant aesthetic improvement. Donor sites showed significant scarring without functional impairment.

CONCLUSION

Free flap repair for head and neck soft tissue defects with bone exposure is feasible and yields good results.

[The useful forehead, the impaired forehead, but the forehead… repaired!]

The forehead, although sometimes hidden by a fringe, is a major region of the face revealing many expressions such as fatigue, surprise, concern, anger… In reconstructive surgery, the forehead is frequently used as a donor site. This article looks at three aspects: the used, traumatised and repaired forehead. The forehead, with its high-quality hairless skin and proximity to the noble structures of the face, is a central donor site. The forehead flap is commonly used for nasal reconstruction, with several variations to meet different needs. Other pedicled flaps, such as the supra-eyebrow flap and the crane flaps, are also used for various facial reconstructions. The forehead can be affected by trauma, burns, vascular lesions and skin tumours. We are particularly interested "en coup de sabre" linear scleroderma, an autoimmune disease that causes cutaneous and subcutaneous fibrosis, sometimes associated with Parry Romberg syndrome. In addition, lesions of the temporal branch of the facial nerve lead to muscular paralysis, affecting the aesthetics and function of the frontal region. Precise knowledge of the anatomy of the nerve pathway is crucial to avoid iatrogenic lesions. The entire arsenal of reconstructive surgery is useful for repairing the forehead. Controlled wound healing, tension suturing and the use of local flaps are key techniques for repairing the forehead. Tension sutures are particularly effective for small losses of substance, and their orientation depends on the location. Advancement, rotation and transposition flaps are used for larger losses of substance. Skin grafts, although less aesthetic, are sometimes necessary. Skin expansion, although socially restrictive, is used to treat congenital giant nevi and increase the surface area of forehead flaps.

A comparison of postoperative outcomes based on recipient vessels in scalp free flap reconstruction: A systematic review and meta-analysis

PURPOSE

The superficial temporal artery (STA) and facial artery (FA) are two commonly used recipient vessels when performing free tissue transfer to the head and neck. This meta-analysis compares the impact of recipient vessel location on free flap outcomes in scalp reconstruction.

METHODS

A systematic review was conducted following PRISMA-P guidelines using six databases. Studies reporting free tissue transfer using the STA or FA as a recipient vessel for reconstructing scalp defects were included. Outcomes of interest included flap loss, partial flap necrosis, wound dehiscence, venous thrombosis, and infection rates. Quality evaluation was performed using ASPS criteria and the ROBINS-I tool.

RESULTS

Of 3270 identified articles, 12 were included for final analysis. In total, 125 free flaps were identified (75 STA, 50 FA). Pooled analysis demonstrated an overall flap survival rate of 98.4% (STA 98.7% vs. FA 98.0%; p = .782). The mean defect size was significantly greater for flaps using the STA compared with the FA (223.7 ± 119.4 cm2 vs. 157.1 ± 96.5 cm2, p = .001). The FA group had a higher incidence of wound dehiscence than the STA group (14.0% vs. 1.3%, p = .005). However, meta-analysis demonstrated no significant difference in rates of wound dehiscence, flap loss, partial flap necrosis, venous congestion, or postoperative infection between groups.

CONCLUSION

This is the first systematic review and meta-analysis to assess recipient vessel selection in scalp reconstruction. Our results do not support a single vessel as the superior choice in scalp reconstruction. Rather, these findings suggest that the decision between using the STA or FA is multifaceted, requiring a flexible approach that considers the individual characteristics of each case. Further research is needed to explore additional factors influencing recipient vessel selection, including defect location, radiation therapy, and prior head and neck surgery.

Scalp Reconstruction With Free Tissue Transfer as a Palliative Surgical Intervention in a High-Risk Population

Microvascular reconstruction of the scalp is frequently indicated in patients with locally advanced tumors, among other etiologies, in a relatively high-risk, older patient population that often has multiple medical comorbidities. A retrospective analysis was performed on patients undergoing microvascular scalp reconstruction at Emory University Hospital and Grady Memorial Hospital between 2011 and 2021. Patient demographics, wound characteristics, operative details, and complications were recorded. Statistical analysis using univariate and multivariate models was performed. Forty-two patients underwent 45 microvascular scalp reconstructive procedures during the study period. The median age was 63 years. Wounds were predominantly oncologic (n=38, 84.4%) and frequently involved deeper structures [calvarium (n=38, 84.4%), dura (n=17, 37.8%)]. At a median follow-up of 350 days, 33 patients (73.3%) had healed flaps, 9 (20.0%) had wound healing issues but ultimately successful reconstruction, and 3 (6.7%) experienced flap failure. Most patients (n=33, 80.9%) were discharged home or to a rehabilitation facility, while the remaining 8 patients (19.1%) were discharged to hospice or died. The 30-day mortality was 4 patients (8.9%) and the 6-month mortality was 8 patients (20.5%). There was a statistically significant difference in 30-day mortality (P=0.0001) on univariate analysis and 6-month mortality (P=0.003) on both univariate and multivariate analysis for patients >70 years. While age >70 years is a risk factor for mortality in patients undergoing microvascular scalp reconstruction, mortality was commonly related to underlying disease processes rather than complication of surgery. Microvascular reconstruction for scalp defects has a high success rate and can be offered as a palliative procedure for patients with locally advanced cancers, advanced age, and multiple comorbidities.

Histopathologic analysis of hyaluronic acid composite solution following intravascular injection: Variability and safety

BACKGROUND

Although a composite solution of non-crosslinked hyaluronic acid is generally considered safe, few studies have investigated its safety after intravascular injection.

METHODS

Male Sprague-Dawley rats were administered 0.05 mL of a non-crosslinked hyaluronic acid composite solution via intravascular injection into bilateral inferior epigastric arteries (IEA). Artery samples were obtained at multiple time points for histopathologic analysis. Bilateral abdominal flaps supplied by the IEA were lifted and the same dose of solution was injected into the artery, and flap survival was analyzed.

RESULTS

Histopathologic analysis showed that the non-crosslinked hyaluronic acid composite solution remained temporarily in the artery lumen following intravascular injection. With continuous blood flow, the filler gradually disintegrated and the artery became recanalized. At 24 h, no filler remained in the lumen. At 7 days after the filler was injected into the IEA feeding the flap, there was no significant difference between the experimental and control groups with respect to flap survival rate.

CONCLUSIONS

Non-crosslinked hyaluronic acid composite solution is relatively safe when a minimal volume is administered by intravascular injection. The filler will remain in the vessel for a short time, after which the vessel recanalizes.

Surgical Management for Hair Restoration: A Review of Contemporary Techniques

BACKGROUND

Hair loss can cause psychological distress for patients, regardless of the etiology or extent of the defect. Many conservative and pharmacological approaches are successful in management, but refractory or severe cases often mandate surgical treatment. Surgical techniques have been refined over the course of a century, and we aim to review the most contemporary strategies.

METHODS

A review of the literature was performed using the databases PubMed, Web of Science, and Embase, in May 2020. Articles were included if they discussed techniques used within the past 10 years, in search of more contemporary strategies and the most widely used approaches.

RESULTS

The use of local flaps, scalp reduction surgery, and hair transplantation techniques are all used for various indications. Modern hair transplantation can be further divided into follicular unit excision and follicular unit transplantation, each with its own advantages. Local flaps are most often used for post-traumatic and reconstructive indication, while hair transplantation can be used for smaller cosmetic lesions or in combination with a variety of other reconstructive techniques.

CONCLUSION

Hair loss continues to be a challenging pathology for both patients and physicians, regardless of etiology. When conservative treatment is inadequate, there exist multiple surgical techniques that can feasibly restore hair, though the exact degree of success may vary between patients. The proper technique is dependent upon etiology, patient specific factors, as well as surgeon experience and comfort.

LEVEL OF EVIDENCE III

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Dermatofibrosarcoma protuberans of the scalp: Surgical management in a multicentric series of 11 cases and systematic review of the literature

BACKGROUND

Dermatofibrosarcoma protuberans is a rare, slow-growing soft-tissue malignancy originating in the dermis that is characterized by an infiltrating growth pattern with a marked tendency of local recurrence. Complete surgical resection with pathological margin clearance must be achieved to reduce the risk of tumor recurrence. Resulting defects often require extensive reconstructive procedures. Dermatofibrosarcoma protuberans of the scalp poses particular challenges owing to the proximity to the face and brain. This study aims to evaluate treatment options and proposes an algorithm for management of scalp dermatofibrosarcoma protuberans based on a multicentric case series and systematic review of the literature.

METHODS

A retrospective multicentric chart analysis of 11 patients with scalp dermatofibrosarcoma protuberans who presented within the last 20 years was performed regarding demographic data, pathological tumor characteristics, and surgical management (resection and reconstruction). Additionally, a further 42 patients (44 cases) were identified through a systematic Preferred Reporting Systems for Systematic Reviews and Meta-Analysis-based review of the literature searching the Medline and Embase databases.

RESULTS

In total, 30 cases were classified as primary and 20 cases as recurring scalp dermatofibrosarcoma protuberans (data from 5 cases were missing). The median tumor size was 24 cm2 (interquartile range 7.8-64), and the median defect size was 55.8 cm2 (interquartile range 48-112). Recurring scalp dermatofibrosarcoma protuberans was more often associated with invasion of deeper layers and required more extensive tumor resection to achieve negative margins. Within the subgroup that was managed with peripheral and deep en face margin assessment, no recurrence was observed. Most patients required local (41. 8%) or free flap (27.8%) reconstruction after dermatofibrosarcoma protuberans resection.

CONCLUSION

Whenever possible, peripheral and deep en face margin assessment-based techniques should be preferred for resection of scalp dermatofibrosarcoma protuberans because they provide superior oncological safety while preserving uninvolved tissue. Patients with locally advanced and recurring scalp dermatofibrosarcoma protuberans often require multidisciplinary treatment including neurosurgery, radiotherapy, and microvascular reconstructive surgery and should be referred to a specialized center.

Patient Reported Outcomes of Scalp and Forehead Reconstruction for Defects Following Oncological Resections (North-East Indian Tertiary Cancer Centre Study)

Background Approximately 1-2% of all scalp tumours are malignant, but they comprise up to 13% of all malignant cutaneous neoplasms. The current study presents our experience of reconstruction of scalp and forehead for malignant tumours treated at our centre. Methods This is a single institutional observational study conducted at a tertiary cancer centre in North East India. Post-operative outcomes related to quality of life of patients were measured with help of FACE-Q scales. Face-Q -Satisfaction with outcome and FACE-Q- appearance related psychosocial distress scores were analysed. Histograms were used for descriptive statistics. Data were checked for normality using Kolmogorov-Smirnova and Shapiro-Wilk test. For non-normal data Wilcoxon test was used. A p value less than 0.05 was considered as statistically significant at 5% level of significance. Results Mean age of patients was 57.6 ± 14.2 years. The mean defect size was 89.036 ± 81.77 cm2. The mean satisfaction with outcome scores and distress scores at 3-months was 54.9 ± 8.6 and 34.8 ± 8.5 respectively with a statistically significant p value of 0.001.Mean satisfaction scores and psychological distress scores were better at the end of three months when compared to at the time of discharge with a statistical significant p value of < 0.0001. Conclusion Scalp and forehead reconstructions for defects following oncological resections are technically challenging and if chosen carefully with meticulous planning, both local and free tissue transfers give satisfactory outcome in long term follow up. There are lots of reconstruction options for scalp and forehead defects and knowledge of the basic bio-geometry of the each flap is must.

Multimodale Therapie bei lokal fortgeschrittenem kutanem Plattenepithelkarzinom

Die Therapieoptionen für lokal fortgeschrittene oder metastasierte Plattenepithelkarzinome waren bisher stark begrenzt und nicht standardisiert. Durch die Zulassung des monoklonalen Antikörpers Cemiplimab, der gegen den programmed death-1-Rezeptor (PD-1) gerichtet ist, hat sich die Prognose der betroffenen Patienten deutlich gebessert, wobei z.T. anhaltende Komplettremissionen erzielt werden können.

In der vorgestellten Kasuistik wurde ein multimorbider, 81-jähriger Patient aufgrund eines ausgedehnten Plattenepithelkarzinoms frontoparietal mit Schädelkalotteninfiltration und Einbruch nach intrakraniell zunächst mit Cemiplimab behandelt. Immunvermittelte Nebenwirkungen sind nicht aufgetreten. Bei klinischer und radiologischer Remission wurde der Restbefund interdisziplinär operativ versorgt, wobei die defekte Schädelkalotte rekonstruiert wurde. Histologisch wurde eine pathologische Komplettremission des Plattenepithelkarzinoms nachgewiesen. 6 Monate postoperativ ergab sich kein Anhalt für ein Lokalrezidiv oder Metastasen.

Dieser Fall zeigt exemplarisch einen Patienten, der trotz seines hohen Alters und Ko-Morbidität von der Therapie mit Cemiplimab profitiert hat. Darüber hinaus demonstriert dieser Fall die Relevanz eines interdisziplinären/multimodalen Therapieregimes im Management dieser in der Inzidenz deutlich ansteigenden Tumorentität.

Perioperative Hypercoagulability in Free Flap Reconstructions Performed for Intracranial Tumors

OBJECTIVE(S)

Patients with intracranial tumors have a higher risk of thromboembolic events. This risk increases at the time of surgical intervention. We have noted an anecdotal increase in perioperative flap thrombosis in patients undergoing free tissue transfer for intracranial tumor resection. This study aims to formally evaluate this risk.

METHODS

A multi-institutional retrospective chart review was performed of patients who underwent free tissue transfer for scalp/cranial reconstruction. Perioperative thrombosis and free flap outcomes were evaluated.

RESULTS

The 209 patients who underwent 246 free tissue transfers were included in the study. The 28 free flap scalp reconstructions were associated with intracranial tumors, 19 were performed following composite cranial resections with associated dural resection/reconstruction, and 199 were performed in the absence of intracranial tumors (control group). There was a significantly higher incidence of perioperative flap thrombosis in the intracranial tumor group (11/28, 39%) when compared to controls (38/199, 19%) (p = 0.0287). This was not seen when scalp tumors extended to the dura alone (4/19, 21%, p = 0.83). Therapeutic anticoagulation used for perioperative thrombosis (defined as intraoperative or in the immediate postoperative phase up to 5 days) was associated with a lower risk of flap failure, although this was not statistically significant (p = 0.148). Flap survival rates were equivalent between flaps performed for intracranial pathology (93.3%) and controls (95%).

CONCLUSION

There is an increase in perioperative flap thrombosis in patients with intracranial tumors undergoing free tissue scalp reconstruction. Anticoagulation appears to mitigate this risk.

LEVEL OF EVIDENCE

This recommendation is based on level 3 evidence (retrospective case-control studies, systematic review of retrospective studies, and case reports) Laryngoscope, 2022.

Multimodale Therapie bei lokal fortgeschrittenem kutanem Plattenepithelkarzinom

Die Therapieoptionen für lokal fortgeschrittene oder metastasierte Plattenepithelkarzinome waren bisher stark begrenzt und nicht standardisiert. Durch die Zulassung des monoklonalen Antikörpers Cemiplimab, der gegen den programmed death-1-Rezeptor (PD-1) gerichtet ist, hat sich die Prognose der betroffenen Patienten deutlich gebessert, wobei z.T. anhaltende Komplettremissionen erzielt werden können.

In der vorgestellten Kasuistik wurde ein multimorbider, 81-jähriger Patient aufgrund eines ausgedehnten Plattenepithelkarzinoms frontoparietal mit Schädelkalotteninfiltration und Einbruch nach intrakraniell zunächst mit Cemiplimab behandelt. Immunvermittelte Nebenwirkungen sind nicht aufgetreten. Bei klinischer und radiologischer Remission wurde der Restbefund interdisziplinär operativ versorgt, wobei die defekte Schädelkalotte rekonstruiert wurde. Histologisch wurde eine pathologische Komplettremission des Plattenepithelkarzinoms nachgewiesen. 6 Monate postoperativ ergab sich kein Anhalt für ein Lokalrezidiv oder Metastasen.

Dieser Fall zeigt exemplarisch einen Patienten, der trotz seines hohen Alters und Ko-Morbidität von der Therapie mit Cemiplimab profitiert hat. Darüber hinaus demonstriert dieser Fall die Relevanz eines interdisziplinären/multimodalen Therapieregimes im Management dieser in der Inzidenz deutlich ansteigenden Tumorentität.

Expanded scalp flap combined with laser hair removal to reconstruct facial defects around the hairline

BACKGROUND

Congenital and acquired facial lesions around the hairline can bring huge physical and psychological trauma to patients. At present, reconstruction of this area remains a challenge. In this study, we present an alternative technique to reconstruct the aesthetic units using an expanded scalp flap combined with laser hair removal.

METHODS

We retrospectively reviewed 25 cases of facial lesions around the hairline reconstructed with this surgical technique between May 2014 and May 2020. Expander was implanted under the scalp as designed before the operation. After the expander was fully expanded, the lesion was removed and the scalp flap was transferred. Laser hair removal was performed on the transplanted skin flap 2 weeks after flap transfer.

RESULTS

There were ten cases of postburn scar, nine cases of congenital nevus, four cases of traumatic scar, one case of haemangioma, and one case of nevus sebaceous. The median times of laser treatment was 3 (range, 1-8). The median follow-up time was 11 months, ranging from 1 to 27 months. The colour and texture of expanded flaps were similar to adjacent tissue in all cases. The direction of reserved hair in transferred flaps was consistent with the direction of hair in the recipient area or contralateral hair. There were no complications, such as infection, blistering, discolouration, and ulceration. All patients were satisfied with the appearance of the reconstructed hairline and the surgical outcomes.

CONCLUSIONS

The expanded scalp flap combined with laser hair removal is a feasible and effective technique to reconstruct both sides of the hairline simultaneously from a single donor site with a good colour match and a similar texture and thickness.

Use of Biologic Agents in Nasal and Scalp Reconstruction

Oncologic reconstruction of the nose and scalp following Mohs micrographic surgery poses a significant challenge for plastic surgeons. While these defects are traditionally reconstructed using primary closure techniques, skin grafts, local flaps, pedicled flaps, and free tissue transfer, the incorporation of biologic healing wound agents such as Integra and Cytal provides patients and surgeons with alterative reconstructive options without additional donor site morbidity. Herein, we review the use of biologic agents used in soft tissue reconstruction of the nose and scalp following Mohs surgery.

Utility of Dermal Wound Matrices Compared with Local-Tissue Rearrangement and Free Flap Reconstruction for Oncologic Scalp Wounds: A Multidisciplinary Dual Matched-Pair Analysis

BACKGROUND

Local tissue rearrangement, free flap reconstruction, and Bilayer Wound Matrix represent reconstructive modalities for coverage of scalp defects; however, preferred indications are less clear. The authors aimed to evaluate the efficacy of these interventions.

METHODS

A retrospective review (2008 to 2019) was performed of subjects requiring soft-tissue reconstruction of oncologic scalp wounds. Subjects were dual matched into two comparative cohorts based on age and wound size/wound age: (1) local tissue rearrangement versus Bilayer Wound Matrix, and (2) free flap reconstruction versus Bilayer Wound Matrix. Ninety-day wound coverage, reoperation rates, hospital length of stay, operative time, and wound complications were compared.

RESULTS

In total, 361 subjects were included. Following matching, 126 subjects constituted the local tissue rearrangement versus Bilayer Wound Matrix cohort, and 56 constituted the free flap reconstruction versus Bilayer Wound Matrix cohort. Local tissue rearrangement/Bilayer Wound Matrix median defect size was 35 ± 42.5 cm2. Local tissue rearrangement provided significantly better wound coverage at 90 days (95.2 percent) compared to Bilayer Wound Matrix (84.1 percent) (p < 0.040), although reoperation rates (7.9 percent versus 15.9 percent) did not differ (p < 0.271). Median defect size in the free flap reconstruction/Bilayer Wound Matrix cohort was 100 ± 101.1 cm2. Ninety-day success (free flap reconstruction, 92.9 percent; Bilayer Wound Matrix, 96.4 percent; p < 1.00) and reoperation rates (14.3 percent versus 3.6 percent; p < 0.352) were similar between groups. Free flap reconstruction had significantly greater operative time (418 minutes versus 100 minutes; p < 0.001) and length of stay (3 days versus 0.5 days; p < 0.001).

CONCLUSIONS

Local tissue rearrangement may be more reliable for smaller wounds (<100 cm2) when compared to Bilayer Wound Matrix. Bilayer Wound Matrix may have comparable efficacy to free flap reconstruction for larger defects (150 to 250 cm2), and may be more cost-effective, given greater operative time and length of stay associated with free flap reconstruction. Free flap reconstruction is preferentially used in complicated large defects in the setting of radiation therapy, and for large defects that have failed Bilayer Wound Matrix.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Reconstruction of Complex Scalp Defects in Different Locations: Suggestions for Puzzle

Objective

Scalp defects may occur following trauma, radiotherapy, oncologic resection, and recurrent surgeries. The hair-bearing scalp has a dual role, which consists of protecting the calvarium and contributing to aesthetic appearance. While the "reconstructive ladder" approach may be used to close small and medium-sized scalp defects, it is not the case for larger ones involving the calvarium or with a radiation therapy history. The aim of this study is to present cases operated due to complex scalp defects, analyze complications, and discuss the choice of reconstruction.

Material and Methods

The study consists of 14 patients who were operated between December 2017 and August 2019 due to a complex scalp defect. Patient were evaluated according to age, gender, etiology, radiation therapy history, defect size and location, reconstruction steps, cranioplasty and duraplasty options, type of free flap, recipient artery, vein graft requirement, and complications.

Results

The mean age of patients, which consists of 11 men and three women, was 56.7 years. The etiology for scalp defects included basosquamous carcinoma, squamous cell carcinoma, giant basal cell carcinoma, atypical meningioma, glioblastoma multiforme, angiosarcoma, and anaplastic oligodendroglioma. The defect involved the full thickness of calvarium in nine cases and pericranium in five cases. Cranioplasties were made with rib graft (n=1), bone graft (n=1), and titanium mesh (n=7). Free flaps used for reconstruction were musculocutaneous latissimus dorsi (LD) (n=4), LD muscle (n=3), anterolateral thigh (ALT) (n=4), musculocutaneous ALT (n=1), vastus lateralis muscle (1), and rectus abdominis muscle (n=1). Flap loss was not observed. Complications occurred in four of the patients; include a partial graft loss, a wound dehiscence, seroma, and an unsatisfactory esthetic result.

Conclusion

Free tissue transfers rather than local flaps should be opted to reconstruct complex scalp defects, as failure of the latter, could create much greater defects, and worse consequences. There are many options for proper reconstruction, and it is essential to select the appropriate one, taking into account the comorbid conditions of each case.

The need for craniofacial trauma and oncologic reconstruction in global surgery

The global burden of surgical disease is concentrated in low- and middle-income countries and primarily consists of injuries and malignancies. While global reconstructive surgery has a long and well-established history, efforts thus far have been focused on addressing congenital anomalies. Craniofacial trauma and oncologic reconstruction are comparatively neglected despite their higher prevalence. This review explores the burden, management, and treatment gaps of craniofacial trauma and head and neck cancer reconstruction in low-resource settings. We also highlight successful alternative treatments used in low-resource settings and pearls that can be learned from these areas.

miR-26b-5p/TCF-4 Controls the Adipogenic Differentiation of Human Adipose-derived Mesenchymal Stem Cells

In this study, we assessed the ability of miR-26b-5p to regulate T cell factor 4 (TCF-4) expression and thereby control human adipose-derived mesenchymal stem cell (hADMSC) adipogenic differentiation. Adipogenic medium was used to induce hADMSC differentiation over a 6-d period. The ability of miR-26b-5p to interact with the TCF-4 mRNA was confirmed through both predictive bioinformatics analyses and luciferase reporter assays. Immunofluorescent staining was used to visualize the impact of miR-26b-5p inhibition or overexpression on TCF-4 and β-catenin levels in hADMSCs. Further functional analyses were conducted by transfecting these cells with siRNAs specific for TCF-4 and β-catenin. Adipogenic marker and Wnt/β-catenin pathway gene expression levels were assessed via real-time polymerase chain reaction and western blotting. β-catenin localization was assessed via immunofluorescent staining. As expected, our adipogenic media induced the adipocytic differentiation of hADMSCs. In addition, we confirmed that TCF-4 is an miR-26b-5p target gene in these cells, and that protein levels of both TCF-4 and β-catenin were reduced when these cells were transfected with miR-26b-5p mimics. Overexpression of this microRNA also enhanced hADMSC adipogenesis, whereas TCF-4 and β-catenin overexpression inhibited this process. The enhanced hADMSC adipogenic differentiation that was observed following TCF-4 or β-catenin knockdown was partially reversed when miR-26b-5p expression was inhibited. We found that miR-26b-5p serves as a direct negative regulator of TCF-4 expression within hADMSCs, leading to inactivation of the Wnt/β-catenin pathway and thereby promoting the adipogenic differentiation of these cells in vitro.

Exchange Cranioplasty Using Bioabsorbable Hydroxyapatite and Collagen Complex After Removal of an Extensive Frontal Bone Tumor in an Infant

BACKGROUND

Forehead reconstruction is challenging. Reconstruction of the innate curvature of the forehead is difficult, and the forehead is an esthetically important part of the face. Although synthetic implants and autologous split bone grafts are useful, these cannot be used in infants.

CASE DESCRIPTION

A 4-month-old girl was presented with a right frontal bone Ewing sarcoma. The tumor was removed, and the defect was reconstructed with an autologous contralateral parietal bone graft. The parietal bone defect was repaired with a bioabsorbable hydroxyapatite and collagen complex. Good reconstruction of the forehead and ossification of the donor site was achieved within 3 years after surgery.

CONCLUSIONS

After removal of an extensive frontal bone tumor in an infant, exchange cranioplasty with an autograft using a bioabsorbable hydroxyapatite and collagen complex at the donor site yielded good results.