Scientific validation of clinical visual scales and Antera 3D™ consistency with derived measurements in the assessment of infantile haemangioma after laser therapy.

BACKGROUND: Laser therapy is a treatment for infantile haemangiomas. The efficacy of laser therapy for red lesions is determined by visual evaluation; however, this assessment is inaccurate and lacks objectivity. OBJECTIVE: To scientifically validate the consistency between pre- and post-treatment visual assessment grades for infantile haemangioma treated with pulsed dye laser (PDL) and the values calculated from images obtained with Antera 3D™. METHODS: This study involved 81 cases of infantile haemangiomas treated with PDL alone from 2012 to 2015 and with Antera 3D™ images of the lesions. Using images obtained before treatment and 4-6 weeks after the last treatment, the lesions were rated using a visual four-step scale. Ratings were categorised as Poor/Fair/Good/Excellent by the degree of improvement in the red colour tone. The red colour ratio was calculated using the haemoglobin distribution in the lesion and surrounding skin, and the improvement difference and improvement rate were then obtained. The correlation between the improvement difference and improvement rate, and visual evaluation was statistically analysed. RESULTS: No serious adverse effects were observed, with an average of 4.3 treatments per patient; 60.1% of the patients achieved Good/Excellent results. There were statistically significant differences in the post-treatment red colour ratio and improvement ratio in each category after visual evaluation classification. The improvement rate and the four visual grades were statistically correlated. CONCLUSION: This study confirmed the scientific validity of visual evaluation and the evaluation criteria calculated from Antera 3D™. This method could objectively determine treatment effectiveness.

An Anatomical Dissection Method for Observation of Fibrous Facial Structures.

BACKGROUND: In recent years, structures including the superficial musculoaponeurotic system and retaining ligaments that support the facial soft tissue have been clarified. However, these structures are very difficult to observe in their entirety by the standard gross anatomical procedure (ie, dissection from superficial to deep layers). Furthermore, accurate descriptions of these structures are rare in both anatomical and plastic surgery textbooks. The aim of this study was to clarify the facial fibrous structures in a gross anatomical view. METHODS: The authors' novel method used soft facial tissue and bone. The tissue was fixed in gelatin and sectioned at a thickness of 5 to 10 mm. Each section was placed on a wooden board; the bone was then pinned, and the skin was pulled outward with sutures to hyperextend the soft tissue. Subsequently, the loose connective tissue was torn and fat tissue was removed under a surgical microscope. After the removal of fat tissue, the fibrous facial structures (eg, the superficial musculoaponeurotic system and retaining ligaments) could be observed clearly. RESULTS: The thickness of the sections allowed three-dimensional observation, such that a structure located deep within a section could be clearly observed. The expansion of soft tissue facilitated observation of the facial layer and fibrous structures, and the locations of nerves and vessels. Therefore, the facial layer structure was readily discerned. CONCLUSION: This method is likely to be very useful in the field of plastic surgery because it enabled intuitive identification of facial layers and their characteristics. CLINICAL RELEVANCE STATEMENT: The dissection method developed by the authors reveals the connected morphology of each tissue of the face, thus providing basic data for analyzing soft tissue changes due to aging and gravity. This will be useful for the development of anti-aging medicine.

Application of Neck Lift Technique for Corrections of Concave Deformity and Scar Contracture After Tracheal Fenestration.

ABSTRACT: Following a tracheostomy or tracheal fenestration procedure, neck concave deformity, and contracture after spontaneous closure are common problems. Since the neck is an exposed part of the body, its concave deformity can cause cosmetic problems and functional problems such as difficulty in neck extension and swallowing due to contracture. We report the case of a 63-year-old man who underwent tracheal fenestration for worsening respiratory status due to sepsis after aspiration pneumonia. After spontaneous closure of the tracheal fenestration, the patient developed a deformity of the neck, impaired neck extension, and dysphagia due to contracture. In this case, the submental sagging skin was used as a subcutaneous pedicle flap to correct the problem, and the result was both functionally and cosmetically satisfactory. We found that the submandibular skin could be used as a random pattern flap for reconstruction of the lower half of the neck. Therefore, this procedure can be an effective method for reconstruction around the tracheal stoma in the future.

Indication for management of oropharyngocutaneous fistulas after head and neck reconstruction using a "stick-shaped platysma flap" technique.

The main strength of the stick-shaped platysma flap technique is it provides adequate tissue volume, while being comparatively simple to perform. It is a highly efficient and straightforward method to close intractable fistulas with minimal morbidity.

Successful Treatment of Full Thickness Frontal Skull Bone Defect With Dermal Fat Grafting and Artificial Bone Grafts.

Rigid reconstruction for frontal bone defects not only improves function, but also approximates more normal appearance. However, in cases involving dural scar contractures, a concave deformation remains when rigid reconstruction is performed without compensating for dead space created by swelling of the brain. This study involved 4 cases in which a 2-stage reconstruction procedure was used to first eliminate dead space by grafting dermal fat, and subsequently carry out rigid reconstruction to achieve a natural forehead configuration. This method is advantageous and considered to be effective in allowing dead space to be easily filled with minimal invasiveness for concave deformations of the dura mater with bone defects. Furthermore, the risk of artificial bone exposure is reduced by adding the dermal component of dermal fat, which is grafted to thinned frontal skin.

Surgical Management of Deep Brain Stimulator Infection without Electrode Removal: Report of Two Cases.

Objective Stimulation of the subthalamic nucleus by implanted electrodes (deep brain stimulation [DBS]) is performed to suppress symptoms of Parkinson's disease. However, postoperative wound dehiscence and infection can require removal of the implanted electrode leads. This report describes treatment of intractable unilateral wound infection in two patients without removing the DBS device. Methods First, components of the DBS system were removed except for the electrode lead and thorough debridement of the infected wound was conducted. Second, the edges of the bone defect left by removal of DBS components were smoothed to eliminate dead space. Subsequently, the electrode lead was covered by using a pericranial-frontalis-muscle flap or a bi-pedicled-scalp flap with good blood supply. Closed intrawound continuous negative pressure and irrigation treatment was conducted for 1 week after the surgery, and then the drain was removed. Results We treated two patients with wound infection after implantation of DBS electrodes. Case 1 developed a cutaneous fistula and Case 2 had wound dehiscence. After treatment by the method described above, complete wound healing was achieved in both patients. Conclusion DBS is always associated with a risk of infection or exposure of components and treatment can be very difficult. We successfully managed intractable wound infection while leaving the electrode lead in situ, so that it was subsequently possible to continue DBS for Parkinson's disease.

Analysis of Scars and Keloids by Focused Ion Beam/Scanning Electron Microscopy: Distinguishing Between Hypertrophic Scars and Keloids.

BACKGROUND: Histological differentiation between hypertrophic scars (HSs) and keloids has been considered difficult. In this study, we analyzed differences in the 3-dimensional tissue architecture between HSs and keloids using focused ion beam/scanning electron microscopy (FIB/SEM). METHODS: Five specimens each of normal skin, normotrophic scars (NSs), HSs, and keloids were investigated. Three sites in each specimen were observed by FIB/SEM tomography, resulting in an observation of 15 sites per tissue type. We identified fibroblasts and macrophages and assessed the contact ratio and the mode of intercellular contact (planar contact or point contact). The significance of differences among the 4 tissue types was determined by Fisher exact test. RESULTS: In normal skin, contact between fibroblasts and macrophages was observed at all 15 sites, and the mode of contact was always planar. There was contact at 87% of the NS sites (planar: point = 80%: 7%). In HSs, contact was seen at 80% of the sites (planar: point = 20%: 60%). In keloids, contact was found at only 15% of the sites (planar: point = 7.5%: 7.5%). The intercellular contact ratio showed no significant differences among normal skin, NSs, and HSs; however, a significant difference was noted between these tissues and keloids. The intercellular contact mode also showed no significant difference between normal skin and NSs, but a significant difference between these tissues and HSs. CONCLUSIONS: These histopathologic findings suggest that FIB/SEM tomography is useful for distinguishing between HSs and keloids and can provide important knowledge for understanding the pathogenesis of keloids.

Late-Onset Infection of Resorbable Plates After Multiple Facial Fractures.

In recent years, a variety of resorbable plates have been used for craniofacial fractures. The authors report a case of plate infection that occurred more than 1 year after surgery and was difficult to distinguish from a foreign body reaction. A 19-year-old male suffered fractures of the right zygomatic bone, orbital floor, and left maxilla in a motorcycle accident. Reduction was performed using resorbable plates at 7 days after injury. The postoperative course was good. However, the patient presented 396 days after surgery with redness/swelling of the right upper eyelid and right cheek pain. There were no systemic signs of infection such as fever. A foreign body reaction to the plate was suspected. After 1 week, swelling of the patient's upper eyelid was worse, and the remaining resorbable plate was removed via a skin incision. Swelling subsequently extended to the right cheek and upper gingiva, and all plates were removed under general anesthesia on the 418th day after the first operation. The swelling subsided after removal of the plates. Pathological examination revealed neutrophil infiltration and Staphylococcus hominis was detected by bacterial culture, leading to a diagnosis of late-onset plate infection. This coagulase-negative staphylococcus usually causes infection in neonates and immunocompromised individuals. Postoperative complications of resorbable plates include foreign body reaction and infection, which are difficult to differentiate clinically. Removing the foreign body is the principal technique for obvious wound infection. A foreign body reaction with subcutaneous fluid retention is slow to heal. Therefore, early plate removal is also recommended.

Closure of Intractable Enterocutaneous Fistula with a Rectus Abdominis Musculocutaneous Flap.

Large enterocutaneous fistulas of the small intestine are rare and difficult to close, particularly if the fistula is associated with massive leakage of digestive juice and the residual intestinal tract is too short for anastomosis. We present a patient who underwent small bowel resection and secondary anastomosis following massive necrosis of the small intestine due to superior mesenteric artery thrombosis. After resection of an enterocutaneous fistula and reanastomosis, the residual small bowel was only 70 cm long with a persistent fistula. We successfully closed the fistula by employing a hinged rectus abdominis musculocutaneous flap. Here, we report our procedure for treating a large enterocutaneous fistula without performing laparotomy and bowel resection.

Experimental study on maintaining the curvature of transplanted cartilage: Influence of the number of cartilage struts.

BACKGROUND: When auriculoplasty is performed for microtia, wire often becomes exposed during the long postoperative period. We have investigated other materials for fixing cartilage. We previously reported that absorbable sutures are more appropriate than wire. The present animal experiments investigated the reasons why fixation of transplanted cartilage is maintained when using absorbable sutures. METHODS: The costal cartilages of Sprague-Dawley rats were harvested, and three cartilage transplant models were prepared. After bending a costal cartilage into a U-shape, it was fixed by using only absorbable sutures as the control or was fixed by suturing one or two cross struts of cartilage to the U-shaped graft. Then the cartilages were subcutaneously transplanted into the backs of the rats. They were removed 8 weeks later, and the return rate of the bent cartilages was assessed. RESULTS: The return rate was 74.0%, in the suture-only group (control), 27.9% in the one-strut group, and 8.3% in the two-strut group. When the sites of contact between the U-shaped graft and the cartilage struts were observed by light microscopy, adhesion of the two cartilages by fibrous connective tissue was observed. CONCLUSION: U-shaped cartilage grafts demonstrated a smaller return rate when there was a larger contact area with the cartilage struts. Each strut was fixed by fibrous connective tissue at the contact site, thereby maintaining the shape of the graft. Thus, when creating a cartilage framework, it is important to fix the bent cartilage to the cartilage struts with a sufficiently large contact area.

Histological study of costal cartilage after transplantation and reasons for avoidance of postoperative resorption and retention of cartilage structure in rats.

BACKGROUND: Limited information is available on the biological status of transplanted cartilage from which the perichondrium has been removed. This article describes the histological and three-dimensional structural picture of cartilage, using green fluorescent protein (GFP) transgenic rats and normal wild rats. METHODS: Three sections of costal cartilage were harvested from 10-week-old wild rats. One section was used as a specimen while two were subcutaneously collected from the dorsal region of 10-week-old GFP rats at 4 and 8 weeks post-transplant. The experiment was performed in two randomized groups. The perichondrium was removed from transplanted cartilage in the first group and perichondrium of transplanted cartilage remained intact in the second group. Histology and focused ion beam/scanning electron microscope (FIB/SEM) tomography were used to evaluate the transplanted cartilage. RESULTS: All 40 transplanted sections were harvested and no infections, exposure or qualitative change of cartilage matrix were seen following transplant. Histological analyses showed that the surface layer of the GFP-negative transplanted cartilage was replaced with GFP-positive chondrocytes 8 weeks post-transplant in the first group. A three-dimensional layer of perichondrium-like tissue reconstructed around the cartilage at 8 weeks was confirmed, resembling normal perichondrium. However, the GFP-positive chondrocytes were not replaced in the second group. CONCLUSIONS: The cell renewal of chondrocytes is necessary for subcutaneously transplanted cartilage to maintain its tissue composition over a long period of time. The histological and ultrastructural analyses revealed that cells from recipient tissue generated new chondrocytes even when cartilage was implanted after removing the perichondrium.

Treatment Outcomes of Locally Advanced Squamous Cell Carcinoma of the Ethmoid Sinus Treated with Anterior Craniofacial Resection or Chemoradiotherapy.

We retrospectively analyzed 14 patients with locally advanced squamous cell carcinoma of ethmoid sinus (LASCC-ES) for the feasibility of anterior craniofacial resection (ACFR). Ethmoid cancer treatment comprised alternating chemoradiotherapy (ALCRT; n = 1), concomitant radiotherapy and intra-arterial cisplatin (RADPLAT; n = 4) and ACFR (n = 9). The 3- and 5-year overall survival (OS) rates of patients were 47.6 and 39.6%, respectively. The 3-year local control (LC) rates of chemoradiotherapy (CRT; ALCRT and RADPLAT) (n = 5) and ACFR (n = 9) groups were 0 and 66.7% (p = 0.012), respectively. The 3-year progression-free survival (PFS) rate of the CRT and ACFR groups were 0 and 55.6% (p = 0.018), respectively. The 3-year OS rate of the CRT and ACFR groups were 0 and 76.2% (p = 0.005), respectively. Postoperative pathological examinations confirmed positive margins in 3 (33%) of 9 cases. The 3-year LC and PFS rates of cases (n = 3) with positive surgical margins were significantly poorer than those of cases (n = 6) with negative surgical margins. Although ACFR for LASCC-ES is a feasible treatment, cases with positive surgical margins were more prone to local relapse. Therefore, surgical safety margins should be thoroughly assessed.

A new modified Pudendal Thigh Flap of vaginoplasty including reconstruction of vaginal vestibule.

We modified the conventional Pudendal Thigh Flap (PTF) on the vaginoplasty including reconstruction of vaginal vestibule. After the operation, no stenosis of the vaginal vestibule and opening of the vagina was observed. It is believed that our technique is cosmetically and functionally possible and a useful method.

Advantage of Extended Craniofacial Resection for Advanced Malignant Tumors of the Nasal Cavity and Paranasal Sinuses: Long-Term Outcome and Surgical Management.

OBJECTIVE: Craniofacial resection (CFR) for advanced sinonasal malignant tumors (SNMTs) is mandatory for radical resection. Surgeons must be aware of perioperative complications and long-term outcome because this procedure is extremely invasive, especially when the tumor involves the anterior skull base. METHODS: Thirty-eight consecutive surgical patients with advanced SNMT of T4 stage or Kadish stage C (31 men and 7 women; mean age, 55 years; range: 19-76 years) treated with CFR in the past 28 years were followed up for 59.4 months. In cases of unilateral orbital extension, en-bloc resection was achieved using several neurosurgical techniques (extended CFR) from 2005 onwards. Herein, we evaluated the safety and effectiveness of surgery by comparing survival data between 2 time periods (first stage: 1984-2004, second stage: 2005-2012). RESULTS: Squamous cell carcinoma was the most common histological type observed (65.8%), followed by esthesioneuroblastoma (15.8%). Using a combination of adjuvant radiation therapy, the 5-year overall survival and the 5-year disease-specific survival rates were 55.5% and 59.4%, respectively. Sarcomatous histology was a poor prognostic factor. The 5-year disease-specific survival rate was 48.9% in the first stage and improved to 82.1% in the second stage (P = 0.057); this was related to improvements in local control rate. CONCLUSIONS: CFR and postoperative radiotherapy are safe and effective for treating advanced SNMTs. Extended CFR, including radical orbital exenteration, may contribute to good long-term outcomes. A diverse surgical team may help perform radical resection and reconstruction in patients with advanced tumors.

The Efficacy of Continuous Negative Pressure and Irrigation Treatment Inside the Wound by a Closed System in Reconstruction of All Layers of the Cranium Accompanying Infection and Cerebrospinal Fluid Leakage.

There have been many reports to date with respect to treatments on reconstruction of the cranium without accompanying infections following trauma and tumor resection. The morality is, however, high in patients observed with generation of cranial bone defect of all layers accompanying infection and cerebrospinal fluid leakage, and moreover, there are barely any reports on such cases because of the reconstruction thereof being very difficult. In this study, the authors were able to cure such 2 cases by carrying out continuous negative pressure and irrigation treatment inside the wound by a closed system following transplant of free latissimus dorsi muscle flap. This method is believed to be very effective for cranial bone defect of all layers accompanying infection and cerebrospinal fluid leakage, in which treatment was determined to be very difficult.

Treatment outcomes of implants performed after regenerative treatment of absorbed alveolar bone due to the severe periodontal disease and endoscopic surgery for maxillary sinus lift without bone grafts.

OBJECTIVE: We have developed a regenerative medicine therapy for the alveolar bone and endoscopic surgery for maxillary sinus lift without bone grafts, in patients experiencing severe periodontal disease with significant absorption of the maxillary alveolar bone, in which more than 10 mm of bone thickness in the maxillary bone was attained, with satisfactory results. The objective of this study was to examine the treatment outcomes of implants that were performed after these therapies. PARTICIPANTS AND METHODS: The participants were 36 patients with severe periodontal disease, who cannot be cured with any other treatments except the extirpation of all teeth. The 36 patients are all patients who underwent regenerative treatment of the alveolar bone through tooth replantation and transplantation of the iliac cancellous bone (the bone marrow) as well as endoscopic surgery for maxillary sinus lift from May 2003 to July 2007 in our clinic. A total of 120 implants were placed in these patients when the replanted teeth fell out because of root resorption, and the success rate was examined. RESULTS: The success rates of the implants were 16 of 33 (48%) in the group when surveyed less than 2 years after the surgery and 84 of 87 (96.5%) in the group when surveyed more than 2 years after the surgery. A statistically significant difference was found between the 2 groups (Chi-squared test, P < 0.001). CONCLUSIONS AND CONSIDERATIONS: It was believed that it takes approximately 2 years for the bones in the maxillary sinus floor, augmented through endoscopic surgery for maxillary sinus lift, to attain the thickness and hardness required for implant placement. Therefore, although the implant treatment should be performed later than 2 years after surgery, chewing is possible during this period, with the replanted teeth that were used for regenerative treatment of the alveolar bone. It is believed that this is an extremely effective treatment method to improve the patients' quality of life.

Maxillary reconstruction using chimeric flaps of the subscapular artery system without vein grafts and the novel usage of chimeric flaps.

The purpose of this study was to overcome the disadvantages associated with the shortness of the vascular pedicle of subscapular system combined flaps when performing the maxillary reconstruction procedure. Combined flaps of the subscapular artery system were used for maxillary reconstruction. A latissimus dorsi myocutaneous flap, a scapular fasciocutaneous flap, and two kinds of scapular bone flaps were elevated as combined flaps. Next, the circumflex scapular artery (CS) and vein were cut off from the combined flaps and anastomosed to the serratus anterior branch, thereby establishing chimeric flaps. Then, maxillary reconstruction was performed using these flaps. We encountered two patients who underwent maxillectomy for maxillary cancer. Satisfactory improvements in facial shape were obtained in both cases. In cases in which combined flaps of the subscapular artery system are used for maxillary reconstruction, the biggest problem is that the vascular pedicle does not reach the recipient vessel in the neck due to the shortness of the CS. Therefore, vein grafts are generally performed to extend the flaps to the maxilla. Our novel procedure has the great advantages of long vascular pedicles and high flexibility in setting the flaps without the use of vein grafts.

Results of intra-wound continuous negative pressure irrigation treatment for mediastinitis.

Intra-wound continuous negative pressure irrigation treatment (IW-CONPIT) was administered to cases of mediastinitis as the therapy of choice, with satisfactory results being obtained in terms of improved survival rates and quick healing of wounds. Accordingly, these treatment results and efficacy were evaluated. After debridement, a sponge was trimmed to conform to the shape of the wound and then it was attached to the surface of the wound. Two tubes with several side holes were placed within the sponge. In cases in which the blood vessels and/or the heart are exposed, an artificial dermis was attached to cover the blood vessels and/or the heart in order to not come in direct contact with the sponge. Next, the top of the wound was covered with polyethylene film to create an air-tight wound seal. A bottle of saline solution was connected to one of the tubes and a continuous aspirator to the other, and continuous negative pressure irrigation of the wound was thus carried out. After performing this treatment for 2-3 weeks, and when wound granulation improved, either skin grafts or the transplantation of muscle flaps was performed as necessary to achieve wound healing. A combination of the continuous negative pressure method and the continuous irrigation method resulted in improved healing rates and lower mortality rates for mediastinitis. It also significantly reduced the number of dressings, as well as the degree of labour and medical materials required; therefore, a reduced hospital stay and shorter treatment period was thus achieved using this treatment method.

Development of the pectoral perforator flap and the deltopectoral perforator flap pedicled with the pectoralis major muscle flap.

PURPOSE: Because thinning of the pectoralis major myocutaneous flap is impossible due to blood circulation, it is difficult to produce thin flaps. Although the pectoral flap and the deltopectoral flap are the best flaps that provide a highly desirable color-texture match to facial skin, their reach is restricted and they require resection in 2 stages. The purpose of this paper is to develop a new method of elevating a flap and to resolve these problems. METHODS: First, include the third intercostal perforating branch of the internal thoracic artery in the skin paddle and, outward therefrom, design a skin paddle of the pectoral flap in accordance with the shape of the defect. After a skin incision along the design, elevate the pectoral flap pedicled with the third intercostal perforating branch. Then, after cutting the third intercostal perforating branch at the lower surface of the pectoralis major muscle, harvest the approximately 5- to 6-cm-wide pectoralis major muscle in the lateral direction. In doing so, it is important to include in the harvested muscle body of the pectoralis major muscle the muscular branch of the third intercostal perforating branch, the branch of thoracoacromial artery, as well as the true anastomosis of both. Thereafter, elevate the entire flap, with the thoracoacromial artery for vascularization, and move it to the head and neck region via the subclavian route. In this way, the pectoral perforator flap pedicled with the pectoralis major muscle flap (PP flap) is elevated. As for the deltopectoral perforator flap with the pectoralis major muscle flap (DPP flap), after elevating the deltopectoral flap pedicled with both the second and third intercostal perforating branches of the internal thoracic artery, carry out the same flap elevation operations. RESULTS: The PP flap was used in 4 cases and the DPP flap was used in 1 case. In all cases, the flaps were completely grafted and quite satisfactory, functional, as well as demonstrating good cosmetic results. DISCUSSION: Unlike the conventional pectoralis major myocutaneous flap, the PP flap does not contain in its skin paddle the pectoralis major muscle and the mammary gland, making it possible to produce a thin flap. In addition, the development of this method has now substantially extended the reach of the flap, thereby making it possible for the PP flap to reach the oropharyngeal region and for the DPP flap to reach the frontal region at a single time. Originally, the skin over the precordium is relatively thin and flexible and provides a desirable color-texture match to facial and neck skin; therefore, it is believed that this method may serve as an extremely useful means in the future in the functional and cosmetic reconstruction of the head and neck region.

Anatomical Research of the Three-dimensional Route of the Thoracodorsal Nerve, Artery, and Veins in Latissimus Dorsi Muscle.

BACKGROUND: The latissimus dorsi (LD) muscle flap has been widely used in facial reanimation surgery. However, there are no standards to what degree the muscle flap may be safely thinned because the three-dimensional positional relationship of thoracodorsal artery, vein, and nerve inside the LD muscle is poorly understood. METHODS: From 18 formalin-fixed cadavers, we made 36 transparent specimens of LD muscles using a newly developed decoloration technique. In 26 specimens, nerve staining (Sihler's staining method) and silicone rubber (Microfil) injection to the thoracodorsal artery were performed, and the relationship of the artery and the vein was examined in 10 specimens. RESULTS: The thoracodorsal artery and vein always ran parallel in a deeper layer compared to the nerve. The thoracodorsal nerve constantly existed in a deeper layer than half (50%) of the muscle in the range of use of the muscle flap in facial reanimation surgery. CONCLUSIONS: The thoracodorsal nerves ran in a shallower layer, and the depth to the nerve in the muscle flap in actual facial reanimation surgery is safe enough to avoid damage to the nerves. The LD muscle may be thinned to half its original thickness safely.