Akimitsu Nishibayashi

DIEP Flap Breast Reconstruction Using 3-dimensional Surface Imaging and a Printed Mold.

Summary: Recent advances in 3-dimensional (3D) surface imaging technologies allow for digital quantification of complex breast tissue. We performed 11 unilateral breast reconstructions with deep inferior epigastric artery perforator (DIEP) flaps (5 immediate, 6 delayed) using 3D surface imaging for easier surgery planning and 3D-printed molds for shaping the breast neoparenchyma. A single- or double-pedicle flap was preoperatively planned according to the estimated tissue volume required and estimated total flap volume. The DIEP flap was then intraoperatively shaped with a 3D-printed mold that was based on a horizontally inverted shape of the contralateral breast. Cosmetic outcomes were assessed as satisfactory, as confirmed by the postoperative 3D measurements of bilateral breasts. We believe that DIEP flap reconstruction assisted with 3D surface imaging and a 3D-printed mold is a simple and quick method for rebuilding a symmetric breast.

Effects of Subcutaneous versus Submuscular Tissue Expander Placement on Breast Capsule Formation

Summary: In autologous breast reconstruction, skin envelope reconstruction is especially important given the flexibility of new breast parenchyma. Our experience suggests a better control of breast shape with subcutaneous tissue expander (TE) placement compared with submuscular TE placement. We speculate that capsule formation might be different in subcutaneous TE placement compared with submuscular TE placement. To elucidate this hypothesis, we collected capsules formed around the TE in two-stage breast reconstruction patients and evaluated differences in histology and capsule wall thickness between subcutaneous (n = 7) and submuscular (n = 8) TE placement. Our findings show that subcutaneous TE placement results in thinner capsule formation with low vascularity when compared with submuscular TE placement (354 ± 96 μm and 589 ± 92 μm, respectively; P < 0.001). Because thin connective tissue can reduce postoperative shrinkage of the skin envelope, it would be beneficial to predict and control the shape of reconstructed breast. Although further study is needed, differences in vascularity between subcutaneous tissue and muscle might affect the thickness of capsules.

Differentiated Adipose-derived Stem Cells Promote Reinnervation of Rat Skin Flaps

Background: Sensory recovery of skin flaps is generally poor unless they are elevated as an innervated flap. The aim of this study was to elucidate if Schwann cell (SC)-like cells differentiated from adipose-derived stem cells (ASCs) could improve the cutaneous nerve regeneration in skin flaps. Methods: Microvascular island groin flaps were elevated bilaterally in 32 Lewis rats. On the right flap, the epigastric nerve was resected and ligated (noninnervated flap), and on the left flap, the nerve was crushed (innervated flap). ASCs, SC-like cells differentiated from ASCs (dASCs), SCs, or vehicle were simultaneously injected to the dermal and hypodermal layers of flap. After 20 weeks, the reinnervation pattern of flap was assessed immunohistochemically using a neuronal marker, PGP9.5. Results: dASC cultures produced significantly higher amount of nerve growth factor and brain-derived neurotrophic factor compared with ASC cultures (P < 0.01), and the level was comparable to that of SC cultures. Although a long-term survival of the transplanted cells was not found, dASCs and SCs significantly increased reinnervation density in the periphery of both types of flaps (P < 0.05), and this effect was more pronounced in noninnervated flaps. On the other hand, ASC transplantation showed no statistically significant effect on the peripheral reinnervation (P > 0.05). In the center of flap, there was no statistically significant increase in reinnervation density in all groups irrespective of flap innervation (P > 0.05). Conclusions: dASCs could improve flap reinnervation by 2 mechanisms: First, neurotrophic factors produced by dASCs facilitated regrowth of cutaneous axons from the surroundings of flap. Second, nerve growth factor released by dASCs induced the collateral sprouting of undamaged axons in adjacent tissues. In addition to the use of innervated flaps, dASC transplantation therapy could be a new approach to improve the sensory recovery of skin flaps.

Correction of complex chest wall deformity in Poland's syndrome using a modified Nuss procedure.

Poland’s syndrome is a rare congenital anomaly, which was first reported in 1841 by Alfred Poland. The chest wall deformity ranges from simple form (absence of the sternocostal head of the pectoralis major muscle) to complex form (simple form plus rib/sternal aberrations and muscular displacement). Since these deficiencies are usually cosmetic, surgical interventions are generally performed in late adolescence or adulthood. However, in cases of severe chest deformities, the parents sometimes wish for early treatment. In such situations, the operative trauma needs to be minimal to prevent any risk of growth inhibition of thorax. We herein describe a method to correct a complex chest deformity with rib aberrations using a modified Nuss procedure, which requires neither cartilage incision nor resection. A 4-year-old boy with Poland’s syndrome was diagnosed with congenital unilateral chest wall deformity on the right side without upper extremity anomalies (Figure 1AeC). Computed tomography scan of the chest showed absence of the sternocostal head of the pectoralis major muscle, and the sternocostal cartilages were rotated and joined together like a ‘vertical bar’. The patient’s chest was measured before the surgery, and the pectus bar with appropriate length was selected. Under general anesthesia, the bar was placed on the chest and bent to conform to the desired chest wall shape similar to the original Nuss procedure. Two 2-cm transverse incisions were made on the bilateral midaxillary lines, and skin tunnels were raised anteriorly. A 2-cm vertical incision was additionally made on the midline of the sternum to raise skin tunnels bilaterally. Through the right lateral incision, previously selected intercostal space (Figure 1D and E, point a) was entered with an introducer. It was then advanced immediately under the ribs until it emerged on the lateral edge of a ‘vertical bar’ of the

Tissue Expander Infection in Breast Reconstruction: Importance of Nasopharynx Screening for Methicillin-resistant Staphylococcus aureus

1 Sir: P infection is cited as a major complication of breast reconstruction using a tissue expander (TE). Once an infection develops, it is difficult to treat, often leading to TE evulsion and increased medical costs. Although there has been extensive research on TE infection risk factors, no studies have evaluated the relationship between the preoperative carrier status of patients and TE infection. This study investigated the correlation between postoperative TE infection and several factors, including preoperative carrier status, in 203 cases with TEs used in breast reconstructions performed between July 2013 and February 2016. This study was approved by the Ethics Committee of Osaka University, and informed written consent for publishing personal and medical information was obtained from all patients. All procedures conformed to the Declaration of Helsinki. All surgical procedures were performed by 2 plastic surgeons following identical protocols. Nasopharyngeal screening for carrier status was performed preoperatively on all patients, and the bacterial strain with the greatest volume and the patient’s methicillin-resistant Staphylococcus aureus (MRSA) carrier status were recorded. Excluding patients whose infections improved conservatively with only antibiotic treatment after drain removal, wound cultures or drainage cultures were performed on patients with an infection, and the phlogogenic bacterium was identified. We also selected the following risk factors: body mass index (kg/m2), method of breast cancer surgery (primary reconstruction only), history of axillary dissection (primary reconstruction only), timing of reconstruction, history of exposure to radiation, location of TE insertion, and amount of saline solution infused during surgery (evaluated based on the proportion of the total amount infused). Statistical analysis was performed using Statcel version 3 (OMS-publishing, Saitama, Japan). The data were analyzed using the chi-squared test. A value of P <0.05 was considered significant. Among the 203 TE cases, postoperative infection developed in 13 (6.4%). In 2 of these cases, the infection was alleviated with antibiotics. The remaining 11 patients required surgery: 9 were successfully treated and 2 underwent TE removal. The risk factor analysis suggested that obesity and preoperative presence of nasopharyngeal MRSA are significant risk factors for postoperative TE infection (Table 1). Additionally, axillary dissection tended to increase TE infection (P = 0.051). In 8 among 12 patients in whom the phlogogenic bacterium was identified, the same bacterium was found to show the greatest volume in the nasopharyngeal cultures (Table 2). In addition to obesity, studies have also reported smoking, chemotherapy, large breast size, etc., as risk factors for postoperative breast prosthesis infection.1, 2 The present study also investigated the relationship between nasopharyngeal carrier status and TE infection. The type of bacteria carried and the phlogogenic bacterium of TE infection were consistent in most patients, suggesting that preoperative nasopharyngeal screening could be effective. Additionally, 4 (33.3%) of the 12 patients who were MRSA carriers developed postoperative TE infections, 3 of whom had MRSA as a phlogogenic bacterium. Although first-generation cephem antibiotics are usually employed as perioperative antibiotics, in the future, research needs to be conducted on the effectiveness of preoperative MRSA eradication and perioperative use of anti-MRSA medications in MRSA carriers.3–5

Differential Reanimation of the Upper and Lower Face Using 2 Interpositional Nerve Grafts in Total Facial Nerve Reconstruction.

Summary: Radical parotidectomy often results in complex facial nerve defects involving the main nerve trunk and multiple distal nerve branches. Although cable nerve grafting often leads to good nerve regeneration, severe synkinesis due to aberrant axonal regrowth is inevitable. In such situations, the use of 2 motor sources to differentially reanimate the upper and lower face could minimize synkinesis. Here we describe a method of total facial nerve reconstruction in which the upper and lower face are differentially reconstructed with the hypoglossal nerve and facial nerve, respectively, using 2 interpositional nerve grafts. Reconstruction of the lower face with the facial nerve restored voluntary and coordinated animation, and reconstruction of the upper face with the hypoglossal nerve restored frontalis muscle tone and eye closure. These results suggest that our method could serve as an alternative to conventional techniques that use only the facial or hypoglossal nerve.

Adipose-derived stem cells protect against endoneurial cell death: Cell therapy for nerve autografts.

One of the major problems with nerve grafts is that the survival of a graft segment, including endoneurial Schwann cells (SCs), is uncertain. We investigated whether the survival of nerve grafts is improved when adipose‐derived stem cells (ASCs) are incorporated into the grafts.

Covering implantable left ventricular assist device (DuraHeart®) with free flap

Severe donor shortage in Japan makes the waiting period for heart transplantation extremely long and the left ventricular assist devices (LVADs) are often used for bridge-to-transplant. We present three cases of infected and exposed DuraHeart® LVAD system treated with free flaps. Four free flaps (two latissimus flaps and two anterolateral thigh flaps) were transferred using the right internal thoracic vessels or left deep inferior epigastric vessels as recipients. The potential significance of the continuous low pressure blood flow generated by the LVAD system on microvascular patency has not been previously reported. All flaps survived and worked efficiently to control the infection and cover the devices. Heart transplantation was conducted in the two of three patients. Free flap transfer is an efficient treatment for the patients with infected and exposed implantable LVAD.

Endothelial cell-derived endothelin-1 is involved in abnormal scar formation by dermal fibroblasts through RhoA/Rho-kinase pathway

Hypertrophic scars and keloids are characterized by excessive dermal deposition of extracellular matrix due to fibroblast‐to‐myofibroblast differentiation. Endothelin‐1 (ET‐1) is primarily produced by vascular endothelial cells and plays multiple roles in the wound‐healing response and organ fibrogenesis. In this study, we investigated the pathophysiological significance of ET‐1 and involvement of RhoA, a member of the Rho GTPases, in hypertrophic scar/keloid formation. We found that ET‐1 expression on dermal microvascular endothelial cells (ECs) in hypertrophic scars and keloids was higher than that in normal skin and mature scars. We also confirmed that ET‐1 induced myofibroblast differentiation and collagen synthesis in cultured human dermal fibroblasts through the RhoA/Rho‐kinase pathway. Finally, since hypertrophic scar/keloid formation was most prominent in areas exposed to mechanical stretch, we examined how mechanical stretch affected ET‐1 secretion in human dermal microvascular ECs, and found that mechanical stretch increased ET‐1 gene expression and secretion from ECs. Taken together, these results suggest that dermal microvascular ECs release ET‐1 in response to mechanical stretch, and thereby contribute to the formation of hypertrophic scars and keloids through the RhoA/Rho‐kinase pathway.

Differentiated adipose-derived stem cells promote the recovery of nociceptor function in rats.

The loss of nociceptive function in the skin because of trauma or surgery can impair the quality of life. The recovery of nociceptor function is mediated by two different axonal responses: nerve growth factor (NGF)-dependent collateral sprouting of undamaged nerves and NGF-independent regeneration of damaged nerves. We reported previously that adipose-derived stem cells (ASCs) can transdifferentiate into Schwann cell (SC)-like cells (dASCs) and that transplantation of dASCs increases axonal density in skin flaps. In the present study, we used an animal model that allowed for the individual assessment of collateral sprouting and regeneration. In-vitro differentiation of ASCs to dASCs significantly increased the production of NGF and brain-derived neurotrophic factor (BDNF) to levels comparable with SCs. In-vivo experiments showed that dASC and SC transplantation significantly increased the area of the mechano-nociceptive field in both collateral sprouting and regeneration models, whereas ASC transplantation exerted no significant effect. Antibody blocking experiment showed that these effects of dASC transplantation in the regeneration model were partly mediated by BDNF. Interestingly, the final areas of nociceptive fields between the two experimental models did not differ significantly for any treatment condition. These results indicate that dASC transplantation differentially facilitates collateral sprouting and axonal regeneration by delivering NGF and other neurotrophic factors (e.g. BDNF), respectively. Although there is a limit to nociceptive field enlargement irrespective of axonal response, dASC transplantation could present a new approach for improving nociceptive function in denervated skin.