Efficacy of the pedicle trapezius muscle flap for the multisurgical removal of pediatric posterior fossa anaplastic ependymoma.

OBJECTIVE: Exceedingly refractory, pediatric anaplastic ependymoma in many cases requires multisurgical removal. The high risk of poor wound healing and CSF leakage especially at the posterior fossa make this tumor difficult to treat. CASE: A 9-year-old girl has had 4th ventricular anaplastic ependymoma since the age of 3. She experienced tumor removal 8 times including 4 posterior fossa craniotomies because tumors were disseminated not only to the posterior fossa but also to the cerebral hemispheres. She also underwent a dermal graft using a free flap. She experienced CSF leaks and meningitis frequently because the wound healing was poor. We performed a dermal flap closure using a pedicle trapezius muscle flap with a plastic surgeon when we performed the 5th tumor removal. RESULT: We achieved complete wound closure in spite of broad deficiencies in subcutaneous and epidermal tissues. After that, recurrences of posterior fossa tumors presented within a short term, and tumor removal via an incision of a pedicle trapezius muscle flap was performed without recurrence of CSF leaks and meningitis. DISCUSSION AND CONCLUSION: For the first time, we are able to report on the efficacy of using the pedicle trapezius muscle flap for multisurgical removal of pediatric posterior fossa anaplastic ependymoma. The muscle flap was found to be effective because of the multiple surgeries expected, and the pedicle trapezius muscle flap was found to be resilient to multiple surgical procedures. Although advantageous, the dorsal scapular artery which is required for flap creation is actually difficult to harvest. Compared to a flee flap, the pedicle trapezius muscle flap maintains vascular supply. Furthermore, this technique has the possibility of being applied to defective dura mater closure that cannot be watertight due to multiple surgeries. However, it is very important to inform the patient's family not only about the improved efficacy of surgery, but also to raise awareness on consequential cosmetic issues.

Preoperative estimation of vertical profunda artery perforator flap weight using computed tomography angiography for breast reconstruction.

BACKGROUND: The vertical profunda artery perforator (v-PAP) flap is limited in terms of the tissue volume that can be harvested but is a suitable graft for Japanese patients with relatively small breast sizes. The objectives of this study were to identify the parameter most closely correlated with v-PAP flap weight on computed tomography angiography (CTA) images and to create an easy-to-use v-PAP flap weight estimation formula by linear regression analysis using the identified parameter. PATIENTS AND METHODS: Thirty v-PAP flaps in 25 patients who underwent breast reconstruction were retrospectively analyzed. Mean age was 46.1 (range: 32-73) years, and mean BMI was 20.0 (range: 15.3-23.6) kg/m2 . On a CT horizontal section of the thigh taken at level of the center of the long axis of the flap, the following parameters were measured from the anterior margin of the gracilis muscle to the posterior margin of the semimembranosus muscle using image processing software: fat area, fat thickness, thigh circumference, and skin paddle area. Linear regression analysis was then performed with the weight of the harvested v-PAP flap as the objective variable and the above parameters as explanatory variables to predict skin flap weight. RESULTS: Correlations with v-PAP flap weight of each parameter were as follows: r = 0.66 (p < .0001) for fat thickness, r = 0.32 (p = .081) for total thigh area, r = 0.36 (p = .054) for thigh circumference, r = 0.27 (p = .153) for skin paddle area, and r = 0.84 (p < .0001) for fat area. Thus, the fat area had the strongest correlation with v-PAP flap weight. The v-PAP flap weight estimation formula obtained by linear regression analysis including fat area was as follows: 7.3 × fat area + 114 (coefficient of determination: R2  = 0.70, p < .0001, RMSE = 24). The engraftment rate of the 30 v-PAP flaps was 100%. One patient developed postoperative venous thrombosis at the vascular anastomosis site, but underwent successful microsurgical revision, leading to flap salvage. During the >6-month follow-up period, there were no notable complications in the reconstructed breasts and donor sites. CONCLUSIONS: The v-PAP flap weight estimation formula we developed in this study showed a high correlation with measured values, allowing for easy estimation using only a single CTA horizontal section of the thigh.

Prevention of denervated muscle atrophy with accelerated nerve-regeneration by babysitter procedure in rat facial nerve paralysis model.

PURPOSE: The "babysitter" procedure is a reconstruction technique for facial nerve complete paralysis and uses the movement source from the healthy facial nerve with a cross-nerve graft. First, an end-to-side neurorrhaphy is performed between the affected facial nerve trunk and hypoglossal nerve for continuously delivering stimuli to the mimetic muscles for preventing the atrophy of mimetic muscles. Despite favorable clinical results, histological and physiological mechanisms remain unknown. This study attempted to establish a model for the "babysitter" procedure and find its efficacy in rats with facial nerve complete paralysis. MATERIALS AND METHODS: A total of 16 Lewis rats were used and divided into 2 groups; cross nerve graft (n = 8) and babysitter groups (n = 8). The facial nerve trunk was transected in both groups. Babysitter group underwent a two-stage procedure. Cross nerve graft group underwent only the transfer of nerve graft from the healthy side to affected side. The animals were assessed physiologically by compound muscle action potential (CMAP), and the regenerated nerve tissues were evaluated histopathologically at 13 weeks after surgery. RESULTS: Facial nucleus stained with retrograde tracers proved the re-innervation of affected facial muscle by the babysitter procedure. In CMAP, the amplitude of babysitter group was significantly higher than that of the cross-facial nerve graft group (p < .05). Histological examination found a significant difference in myelin g-ratio between two groups (p < .05). CONCLUSION: This study investigated the "babysitter" procedure for rat facial nerve palsy. Babysitter procedure shortened the denervation period without mimic muscle atrophy.

Surgical anatomy of ovine facial and hypoglossal nerves for facial nerve reconstruction and regeneration research: An experimental study in sheep.

BACKGROUND: The lack of a clinically relevant animal model for facial nerve research is a challenge. The goal of this study was to investigate the anatomy of the ovine facial and hypoglossal nerves to establish a clinically relevant facial nerve research model. MATERIALS AND METHODS: Six cadaver female Merino sheep (33.5 ± 3 kg, approximately 3 years old) and three anesthetized female Merino sheep (30 ± 3 kg, approximately 3 years old) were used. In cadaver sheep, a right side preauricular to submandibular incision was made. Dimensions of the face, neck, and length of facial nerve were measured. In anesthetized sheep, each facial nerve branch and hypoglossal nerve in the right side was stimulated. The number of myelinated fibers was analyzed histologically. RESULTS: The facial nerve exited the stylomastoid foramen and divided into upper and lower branches. The lower branch then subdivided into buccal and marginal mandibular branches. The hypoglossal nerve was observed behind the digastric posterior belly. Stimulation revealed the temporal, zygomatic, buccal, marginal mandibular, and cervical branch innervated the forehead, orbicularis, upper lip and nasal, lower lip, and platysma, respectively. The number of myelinated fibers of the main trunk, upper, buccal, lower branch, and hypoglossal nerve was 11 350 ± 1851, 4766 ± 1000, 5107 ± 218, 3159 ± 450, and 7604 ± 636, respectively. The length of the main trunk was 9.2 ± 1.5 mm, and distance of the marginal mandibular branch to the facial artery was 94 ± 6.8 mm. CONCLUSIONS: Due to the similarity in nerve anatomy and innervation, the ovine model can be used as a clinically relevant and suitable model for facial nerve research.

One-stage reconstruction by dual-innervated double muscle flap transplantation with the neural interconnection between the ipsilateral masseter and contralateral facial nerve for reanimating established facial paralysis: A report of 2 cases.

The authors developed a one-stage double-muscle reconstruction technique for facial paralysis using a latissimus dorsi (LD) flap and a serratus anterior (SA) flap, which were dually reinnervated by the contralateral facial nerve (FN) and ipsilateral masseter nerve (MN). The procedure was performed for 61-year-old man 3-years after resection of a malignant tumor and a 24-year-old woman 10-years after temporal fracture with facial paralysis. A double-muscle flap comprising left LD and SA flaps was harvested, a 15-cm thoracodorsal nerve (TN) section was attached to the LD flap, and 5-cm and 1-cm sections of the long thoracic nerve (LTN) were attached to the proximal and distal sides of SA flap. The LD flap and SA flap were sutured along the direction of motion of the zygomaticus major and risorius muscles, respectively. The contralateral FN and ipsilateral MN were interconnected by nerve suturing: the medial branch of TN to the distal end of LTN, the proximal end of LTN to the ipsilateral MN, and the buccal branch of contralateral FN to the main trunk of TN. After surgery, good contraction of the transferred flaps resulted in reanimation of a natural symmetrical smile; no complications were observed during the 12-month follow-up period.

A collagen-coated PGA conduit for interpositional-jump graft with end-to-side neurorrhaphy for treating facial nerve paralysis in rat.

PURPOSE: This study investigated the potential of collagen-coated polyglycolic acid (PGA) tube with interpositional jump graft (IPJG) in rat. MATERIALS AND METHODS: A total of 16 Lewis rats were used in this study. Facial nerve paralysis was created by ligating facial nerve trunk with a ligature clip. The rats were divided into 3 groups. Nerve conduit group (n = 6) were treated by IPJG with collagen-coated PGA tubes between the facial nerve trunks and the hypoglossal nerves. Autograft group (n = 6) were treated by IPJG with the greater auricular nerves. As the control group (n = 4), non-treated-model rats with facial nerve paralysis were used. The number of myelinated fibers, fiber diameter, axon diameter, myelin thickness, and g-ratio, were analyzed histologically at 13 weeks after surgery. Compound muscle action potential (CMAP) and retrograde tracing were measured. RESULT: Although the number of myelinated fibers in autograft group (1957 ± 775) had significantly higher than that of nerve conduit group (90 ± 41, P < .05), the nerve conduit group showed the regeneration of myelinated nerve axons. CMAP amplitude values of the autograft (4706 ± 1154 µV) and the nerve conduit groups (4119 ± 1397 µV) were significantly higher than that of the control group (915 ± 789 µV, P < .05). Retrograde tracing confirmed the double innervation of mimetic muscles by the facial and hypoglossal nucleus in both groups. CONCLUSION: This study showed histologically and physiologically the superior effectiveness of performing IPJG with a collagen-coated PGA conduit in a rat model.

Adipose-derived stem cells and the stromal vascular fraction in polyglycolic acid-collagen nerve conduits promote rat facial nerve regeneration.

Adipose-derived stem cells (ADSCs) and the stromal vascular fraction (SVF) promote nerve regeneration. Biodegradable nerve conduits are used to treat peripheral nerve injuries, but their efficiencies are lower than those of autologous nerve grafts. This study developed biodegradable nerve conduits containing ADSCs and SVF and evaluated their facial nerve regenerating abilities in a rat model with a 7-mm nerve defect. SVF and ADSCs were individually poured into nerve conduits with polyglycolic acid-type I collagen as a scaffold (ADSCs and SVF groups). The conduits were grafted on to the nerve defects. As the control, the defect was bridged with polyglycolic acid-collagen nerve conduits without cells. At 13 weeks, after transplantation, the regenerated nerves were evaluated physiologically and histologically. The compound muscle action potential of the SVF group was significantly higher in amplitude than that of the control group. Electron microscopy showed that the axon diameter of the SVF group was the largest, followed by the ADSC group and control group with significant differences among them. The SVF group had the largest fiber diameter, followed by the ADSC group and control group with significant differences among them. The ADSC group had the highest myelin thickness, followed by the SVF group and control group with significant differences among them. Identical excellent promoting effects on nerve regeneration were observed in both the ADSC and SVF groups. Using SVF in conduits was more practical than using ADSCs because only the enzymatic process was required to prepare SVF, indicating that SVF could be more suitable to induce nerve regeneration.

Improvement of the salvage-rate of flap after venous thrombosis with intraparenchymatous venous pressure monitoring.

PURPOSE: Intraparenchymatous venous pressure (IVP) monitoring in flap can measure venous pressure with catheter placement. Among patients with IVP monitoring, this study reviewed postoperative microvascular complications for investigating the transplanted-tissue salvage-rate. PATIENTS AND METHODS: Two hundred and seventy-one patients (male, 132; female, 139; mean age, 52.3 years; age range, 9-82 years) underwent free flap transfer and postoperative continuous IVP monitoring, which performed as follows; a venous catheter was connected to a transducer, and venous pressure in the flap was recorded for three consecutive days postoperatively. The threshold of alarm for elevated venous pressure was set at 50 mm Hg. When abnormal measurements or fluctuation were observed, the vascular anastomotic site was exposed immediately. The flap salvage-rate of non-IVP monitoring group (n = 393; male, 305; female, 81; mean age, 61.3 years; age range, 23-83 years), which were confirmed by a portable ultrasonographic device, was compared with that of IVP-monitoring group. RESULTS: Twenty-one patients developed postoperative microvascular complications at the vascular anastomosis sites. Sensitivity rate of IVP monitoring was 86%; specificity rate, 96%; positive predictive value rates, 64%; negative predictive value rate, 99%; false positive rate, 4%. The flap salvage-rate was 83% in venous thrombosis cases and only 33% in arterial thrombosis cases. In non-IVP monitoring group, flap salvage-rate was 20% with arterial thrombosis and 36% with venous thrombosis, resulting in an increasing the salvage-rate (P = .021). CONCLUSIONS: IVP monitoring could visualize and quantify venous pressure waves in flap and detect early microvascular complications, resulting in a marked improvement in the graft-tissue salvage-rate.

Axonal supercharged interpositional jump-graft with a hybrid artificial nerve conduit containing adipose-derived stem cells in facial nerve paresis rat model.

PURPOSE: Interpositional jump-graft (IPJG) technique with the hypoglossal nerve for supercharging can be applied in a facial nerve paresis case. In IPJG, an autologous nerve is required, and the donor site morbidity is unavoidable. Biodegradable nerve conduits are made from polyglycolic acid (PGA) and used recently without donor site complications after providing autologous grafts. Hybrid artificial nerve conduits with adipose-derived stem cells (ASCs) also attract attention as a nerve-regeneration enhancing agent. This study examined the effect of hybrid artificial nerve conduit on IPJG. MATERIALS AND METHODS: A total of 34 Lewis rats were used and divided into 4 groups by the bridge materials: autograft (n = 8), PGA nerve conduit (n = 8), hybrid PGA nerve conduit with ASCs (n = 8), and the nontreated control groups (n = 8). ASCs were collected from 2 rats and cultured. The animals were assessed physiologically and histopathologically at 13 weeks after surgery. RESULTS: In compound muscle action potential, the amplitude of hybrid PGA group (3,222 ± 1,779 µV) was significantly higher than that of PGA group (1,961 ± 445 µV, P < .05), and no significant difference between hybrid PGA and autograft group. All treated groups showed a myelinated nerve regeneration with double innervation in hypoglossal and facial nerve nuclei for vibrissal muscle. CONCLUSION: This study showed the effectiveness of IPJG with a hybrid PGA conduit especially in physiological examination.

Adipose-derived aldehyde dehydrogenase-expressing cells promote dermal regenerative potential with collagen-glycosaminoglycan scaffold.

Aldehyde dehydrogenase (ALDH) is an enzyme that plays an important role in retinoid metabolism and highly expressed in stem cells. This study isolated ALDH-expressing cells from subcutaneous adipose tissue and investigated their potential to enhance healing in a full-thickness skin wound in rats by co-implanting them with collagen-glycosaminoglycan (c-GAG) scaffolds. ALDH-positive cells were isolated by a fluorescence-activated cell sorting technique from Lewis rat's stromal-vascular-fraction (SVF) and transplanted with c-GAG scaffolds in a rat full-thickness skin wound model. At 7 days after surgery, the microscopic appearance of c-GAG scaffolds seeded with ALDH-positive was compared with those of uncultured-SVF, and cultured-SVF adipose-derived stromal cells (ASCs). The thickness of cellular ingrowth in the ASC group (630 ± 180 µm) was significantly thicker than that in the control (390 ± 120 µm) or SVF (380 ± 140 µm) groups, but non-significantly thicker than that in the ALDH-positive group (570 ± 220 µm). The thickness of regenerated collagen layer was significantly thicker in the ALDH-positive group (160 ± 110 µm) than in the ASCs (81 ± 41 µm), the control (65 ± 24 µm), or SVF (64 ± 34 µm) groups. Immunofluorescent staining with CD31 proved that transplanted ALDH-positive cells differentiated into vascular endothelial cells in c-GAG scaffolds. Combined transplantation with c-GAG scaffolds and adipose-derived ALDH-positive cells promoted dermal regeneration, giving a possibility that ALDH-positive cells would greatly shorten the waiting period before secondary autologous skin grafting was possible.

Facial-nerve regeneration ability of a hybrid artificial nerve conduit containing uncultured adipose-derived stromal vascular fraction: An experimental study.

PURPOSE: This study investigated the potential of uncultured-stromal-vascular-fraction (SVF) cells in promoting facial nerve regeneration in a rat model. MATERIALS AND METHODS: A 7-mm nerve defect was created in the buccal branch of facial nerve in five groups of Lewis rats (total n = 30, n = 6 per group). A silicone tube, infused with syngeneic uncultured-SVF was implanted into the facial nerve defect. Groups 1-3 received 1 × 103 , 1 × 105 , and 1 × 107 cells, and regenerated nerves were examined at 13 weeks after the surgery. The findings were compared to the autograft and collagen-alone groups with facial palsy score (FPS), the number of myelinated fibers, fiber diameter, axon diameter, myelin thickness, and g ratio. RESULTS: There was no significant difference in FPS between the autograft and 1 × 105 -cell groups at 13 weeks after surgery, and FPS values of these two groups were significantly higher than those of the other three groups (P < 0.01). Axon diameter significantly increased in the 1 × 105 -cell group compared with the 1 × 103 - (P < 0.05) and 1 × 107 -cell groups (P < 0.01). Myelin thickness was found to be the highest in the autograft group, followed by the 1 × 105 -, 1 × 103 -, 1 × 107 -cell, and negative control groups, and there were significant differences among all groups (P < 0.01). CONCLUSION: The infusion of uncultured-SVF into the artificial nerve conduit promoted optimal nerve regeneration that was significantly better than nerve conduit alone. © 2016 Wiley Periodicals, Inc. Microsurgery 37:808-818, 2017.

Vascularized versus nonvascularized island median nerve grafts in the facial nerve regeneration and functional recovery of rats for facial nerve reconstruction study.

Histological and physiological basis of the therapeutic efficacy of the vascularized autologous nerve graft in facial nerve regeneration remains poorly understood because of no established rat model. The left median nerve and median artery/vein of Lewis rats were collectively ligated, and harvested as a vascularized island median nerve, which was transplanted to a 7-mm gap in the left buccal branch of facial nerve. Nerve regeneration was investigated. The numbers of myelinated fibers, axon diameter, and myelin thickness were significantly higher in the vascularized nerve graft group than in the nonvascularized nerve graft group. Compound muscle action potential measurement showed that the parameters of vascularized group were similar to those in the intact control group. A vascularized median nerve graft resulted in better facial nerve regeneration outcomes.

Nipple Shield Made from a Thermoplastic with Aluminum Properties.

Here, we report the preparation of a nipple shield from an inexpensive and re-formable thermoplastic with metallic properties as well as its favorable outcomes when used for patients who had undergone nipple reconstruction. The nipple shield was prepared from a material made of a mixture of a thermoplastic resin and special aluminum pellets (aluminum content, 70%). Each patient wore the nipple shield for 3 months after nipple reconstruction. The material was re-softened for re-forming into an adequate shape as required during this 3-month period. All reconstructed nipples were securely protected, with no complications (eg, ulceration, wound dehiscence, and wound infections) during the 3-month period. Also, there were no skin complications such as contact dermatitis or cellulitis in the area where the nipple shield was in contact with the skin. None of the patients stopped using the nipple shield because it came off frequently, or was uncomfortable or painful to wear, and there were no cases in which the nipple shield had to be remade due to damage. The thermoplastic material used in this study appeared to be extremely useful as a nipple protection material because of its good breathability, attributed to its nonwoven form, its low thermal conductivity and resulting cooling effect attributed to its aluminum content, its suitability for rapid re-forming, and its washability.

Minimal Scar Autologous Breast Reconstruction with Skin-sparing Mastectomy.

A skin paddle severely impairs the appearance of the reconstructed breast. We have established a new technique called "minimal scar autologous breast reconstruction" involving delayed nipple reconstruction using a local flap designed on the skin paddle and simultaneous resection of the residual skin paddle. Methods: We analyzed 20 patients with unilateral breast cancer who underwent skin-sparing mastectomy followed by immediate breast reconstruction using a free flap (deep inferior epigastric perforator flap in 13 patients and profunda artery perforator flap in seven). Approximately 1 year after primary reconstruction, nipple reconstruction using an arrow flap designed on the skin paddle and resection of the residual skin paddle were performed. Several months later, medical areola tattooing was performed. Bilateral breast symmetry scores, obtained from the distances between anatomic landmarks, were compared before and after breast reconstruction. Results: Postoperative complications such as necrosis of the reconstructed nipple were not observed after two-stage reconstruction, and all procedures including total resection of the skin paddle, nipple reconstruction, and medical tattooing were performed successfully in all cases. Aesthetic outcomes were excellent: comparison of symmetry scores showed no significant differences in any parameters between before surgery and after reconstruction of the nipple-areola complex. Conclusions: We have established step-by-step strategies for mastectomy, autologous breast reconstruction, and then nipple reconstruction, keeping in mind that the skin paddle would later be totally resected in nipple reconstruction, and thereby achieved breast reconstruction with markedly reduced postoperative scarring compared with conventional autologous breast reconstruction.

Estimation of Mastectomy Volume Using Preoperative Mastectomy Simulation Images Acquired by the Vectra H2 System.

Preoperative prediction of breast volume is very important in planning breast reconstruction. In this study, we assessed the usefulness of a novel method for preoperative estimation of mastectomy volume by comparing the weight of actual mastectomy specimens with the values predicted by the developed method using the Vectra H2. Methods: All patients underwent skin-sparing mastectomy and immediate autologous breast reconstruction. Preoperatively, the patient's breast was scanned using the Vectra H2 and a postmastectomy simulation image was constructed on a personal computer. The estimated mastectomy volume was calculated by comparing the preoperative and postmastectomy three-dimensional simulation images. Correlation coefficients with the estimated mastectomy volume were calculated for the actual mastectomy weight and the transplanted flap weight. Results: Forty-five breasts of 42 patients were prospectively analyzed. The correlations with the estimated mastectomy volume were r = 0.95 (P < 0.0001) for actual mastectomy weight and r = 0.84 (P < 0.0001) for transplanted free-flap weight. The mastectomy weight estimation formula obtained by linear regression analysis using the estimated mastectomy volume was 0.98 × estimated mastectomy volume + 5.4 (coefficient of determination R2 = 0.90, P < 0.0001). The root-mean-square error for the mastectomy weight estimation formula was 38 g. Conclusions: We used the Vectra H2 system to predict mastectomy volume. The predictions provided by this method were highly accurate. Three-dimensional imaging is a noncontact, noninvasive measurement method that is both accurate and simple to perform. Use of this effective tool for volume prediction is expected to increase in the future.

Basic fibroblast growth factor-impregnated collagen gelatin sponge completes formation of dermis-like tissue within 2 weeks: A prospective cohort study.

Introduction: This study included patients who underwent full-thickness skin reconstruction using a two-stage procedure comprising basic fibroblast growth factor-impregnated collagen gelatin sponge (bFGF-CGS) implantation and autologous skin grafting, and the take rate of skin grafts was compared between groups of patients who underwent autologous skin grafting after a waiting period of <2 weeks or ≥2 weeks. Methods: An acute, full-thickness skin defect was treated with thorough debridement of contaminated/necrotic tissue, followed by washing with saline and hemostasis with electrocautery. Then, an FGF-CGS was fixed to the skin defect wound using non-absorbable sutures, and after confirming regeneration of sufficient dermis-like tissue, the second-stage autologous skin grafting was performed for wound closure. Patients were divided into two groups according to the waiting period before the second operation, namely, <2 weeks (early group) and ≥2 weeks (late group), and the take rate of skin grafts was compared. Results: We enrolled and treated 25 cases (18 men, 7 women; mean age: 49 [range 2-86] years). The mean take rate of skin grafts was 93% (range 80%-100%) in the early group and 92% (range 65%-100%) in the late group, with no significant difference between the two groups. There was a significant difference between the groups in mean time to complete healing: 25.2 ± 9.7 days in the early group vs 44.7 ± 27 days in the late group (p < 0.05). Conclusion: Our data suggest that bFGF-CGF can form dermis-like granulation tissue with sufficient quality as a graft bed for skin transplantation within 2 weeks.

Fibroblast Growth Factor-Impregnated Collagen-Gelatin Sponge Improves Keratinocyte Sheet Survival.

Commercially available cultured epithelial keratinocyte sheets (KSs) have played an essential role in wound healing over the past four decades. Despite the initial uptake by the dermal elements, the survival rate of KS on the dermis-like tissue generated by conventional artificial dermis (AD) is low, making this method unsuitable for standard treatments. Therefore, an innovative AD such as collagen-gelatin sponge (CGS) that maintains the release of human recombinant basic fibroblast growth factor (bFGF) may promote wound healing. In this study, we examined whether combination therapy with KSs and CGS with bFGF (bFGF-CGS) could enhance KS survival by heterologous grafting by transplantation of human-derived KSs in an athymic nude rat wound model of staged skin reconstruction. The CGSs were implanted into skin defect wounds on athymic nude rats, which were then divided into two experimental groups: the bFGF group (CGSs containing bFGF, n = 8) and the control group (CGSs with saline, n = 8). Two weeks after implantation, human epithelial cell-derived KSs were grafted onto the dermis-like tissue, followed by assessment of the survival and morphology at 1 week later using digital imaging, histology (hematoxylin and eosin and Masson's trichrome staining), immunohistology (von Willebrand factor), immunohistochemistry (cytokeratin 1-5-6, Ki-67), and immunofluorescence (collagen IV, pan-cytokeratins) analyses. The bFGF group showed a significantly higher KS survival area (86 ± 58 mm2 vs. 32 ± 22 mm2; p < 0.05) and increased epidermal thickness (158 ± 66 µm vs. 86 ± 40 µm; p < 0.05) compared with the control group, along with higher dermis-like tissue regeneration, neovascularization, epidermal maturation, and basement membrane development. These results indicate that the survival rate of KSs in the dermis-like tissue formed by bFGF-CGS was significantly increased. Therefore, combination treatment of bFGF-CGS and KSs shows potential for full-thickness skin defect reconstruction in clinical situations. Impact statement This study highlights how using a combination of cultures, keratinocyte sheets, and collagen-gelatin sponge containing basic fibroblast growth factors can significantly improve cell survival in athymic nude rats with staged skin reconstruction. Our study makes a significant contribution to the literature because it highlights a novel and improved strategy for treating a very common condition such as skin wounds arising from many conditions. Clinical translation of this study may be useful for treating skin wounds.

An electrophysiological evaluation method for the ovine facial nerve.

INTRODUCTION: Large-animal models such as sheep for facial nerve regeneration research have not yet been established because of the lack of methods for assessing the electrophysiological function of regenerated nerves. In this study, we developed a percutaneous measurement method for the evoked compound muscle action potential (CMAP) of the facial nerve in sheep. METHODS: Six 3-year-old castrated male Corriedale sheep were used in this study. Under general anesthesia, an anatomical exploration was performed to identify the course of the buccal branch of the facial nerve and its innervating muscles on one side, followed by the application of surface stimulating electrodes to the contralateral side of the face along the course of the buccal branch of the facial nerve to obtain CMAP measurements of the nasolabial levator muscle. RESULTS: Percutaneous CMAP measurements of the nasolabial levator muscle could be obtained in all animals by placing stimulating electrodes 1 cm apart on the line coinciding with the course of the buccal branch of the facial nerve revealed by the preceding anatomical exploration. Mean values for electrophysiological parameters were amplitude 4.7 ± 0.7 mV, duration 2.1 ± 0.6 ms, and latency 3.6 ± 0.4 ms. CONCLUSION: We have established a percutaneous measurement method for CMAP of the buccal branch of the facial nerve in sheep. This method is expected to be very useful in future studies of facial nerve regeneration for long nerve defects in sheep.

Facial nerve regeneration with bioabsorbable collagen conduits filled with collagen filaments: An experimental study.

INTRODUCTION: A bioabsorbable collagen conduit (Renerve™) filled with collagen filaments is currently approved as an artificial nerve conduit in Japan and is mainly used for connecting and repairing peripheral nerves after traumatic nerve injury. However, there are few reports on its applications for reconstructing and repairing the facial nerve. The present study evaluated the efficacy of the conduit on promoting nerve regeneration in a murine model with a nerve defect at the buccal branch of the facial nerve. METHODS: Under inhalational anesthesia and microscopic guidance, the buccal branch of the left facial nerve in an 8-week-old Lewis rat was exposed, and a 7 mm gap was created in the nerve. The gap was then connected with either the nerve conduits (NC group) or an autologous nerve graft (the autograft group). At 13 weeks after the procedure, we compared the histological and physiological regenerations in the both groups. RESULTS: We found compound muscle action potential amplitude is significantly larger in the autograft group (2.8 ± 1.4 mV) than in NC group (1.3 ± 0.5 mV) (p < 0.05). The number of myelinated fibers of the autograft group was higher (3634 ± 1645) than that of NC group (1112 ± 490) (p < 0.01). The fiber diameter of the autograft group (4.8 ± 1.9 µm) was larger than that of NC group (3.8 ± 1.4 µm) (p < 0.05). The myelin thickness of the autograft group was thicker than that of NC group (0.6 ± 0.3 µm vs. 0.4 ± 0.1 µm) (p < 0.05). G-ratio of the autograft group (0.74 ± 0.19) was lower than that of NC group (0.79 ± 0.10) (p < 0.05). CONCLUSION: This study demonstrated the efficacy of collagen nerve conduit for facial nerve reconstruction following nerve injury. However, the effectiveness of the conduit on the promotion of nerve regeneration was inferior to that of the autograft.

NPWTi allows safe delayed free flap repair of Gustilo IIIb injuries: A prospective case series.

INTRODUCTION: Free flap lower extremity repair is associated with a high complication rate (>31%); higher rates are observed in more severe patients. In cases requiring prior systemic/local stabilization, delayed repair increases complication rate (+10% at 7 days): Negative-pressure Wound Therapy (NPWT) decreases complications but only when applied for less than 7 days. Recent limited evidence suggests that augmentation of NPWT with instillation for wound irrigation (NPWTi) might safely extend such window. This study hypothesizes that, through the combined cleansing effect of NPWT and instillation, NPWTi allows safe (low complication rate) delayed free flap repair in severe patients with Gustilo IIIb injuries (GIIIb). METHODS: A prospective case series was designed (inclusion criteria: GIIIb requiring microsurgical repair, severe patient/injury condition preventing immediate/early repair; exclusion criteria: allergy to NPWTi dressing). Patients received NPWTi (suction: 125 mmHg continuous; irrigation: NaCl 0.9%) until considered clinically ready for repair. Preoperative/postoperative complications (dehiscence, wound infection, bone non-union, osteomyelitis, flap failure) were monitored with clinical signs, imaging, and serum markers (CRP, WBC). RESULTS: Four patients (male: N = 4, female N = 1; Age: 59 [44-75] years-old) were treated. NPWTi was applied for 15.2 [9-28] days. No complication (0%) was observed preoperatively or postoperatively. Delayed repair occurred by latissimus dorsi musculocutaneous flap (N = 3), and anterolateral thigh flap (N = 2). All patients walked weight-bearing 12 [6-20] weeks after injury. CONCLUSIONS: NPWTi seems to allow safe delayed free flap repair in patients with severe lower extremity injuries unable to undergo immediate/early repair.