Analysis of Operation Duration in Thoracodorsal Artery Perforator Free-Flap Surgery of the Lower Extremities.

PURPOSE: This retrospective study aimed to identify the factors that affect the duration of thoracodorsal artery perforator (TDAP) free-flap surgery and to offer strategies for optimizing the surgical procedure. METHODS: We analyzed 80 TDAP flap surgeries performed by a single surgeon between January 2020 and December 2022, specifically focusing on free flaps used for lower-extremity defects with single-artery and single-vein anastomosis. The operation duration was defined as the time between the surgeon's initial incision and completion of reconstruction. Linear regression analyses were conducted to identify the factors affecting operation duration. RESULTS: The average operative duration was 149 minutes (range, 80-245 minutes). All flaps survived, although 8 patients experienced partial flap loss. The operative duration decreased with increasing patient age and when end-to-end arterial anastomosis was performed. However, the risk increased with larger flap sizes and in patients with end-stage renal disease. CONCLUSIONS: Our study identified several factors and methods that could accelerate TDAP free-flap procedures. These findings offer valuable insights for optimizing surgical processes and improving overall surgical outcomes. Although further research is needed to confirm and expand upon these findings, our study provides important guidance for surgeons in developing effective strategies for TDAP flap surgery.

Customized Reconstruction of Lower Eyelid Defects.

BACKGROUND: A lower eyelid defect is a loss of skin, muscle, and underlying structures that can occur due to trauma, malignant or benign tumors, burns, or other causes. The conventional surgical treatment of lower lid defects has several limitations, including visible scarring, narrowing of the eye, and ectropion. Here, we combined the use of a customized mid-face lift with a free mucochondral graft to overcome the disadvantages of existing methods. METHODS: Forty patients underwent reconstructive surgery using a customized mid-face lift with or without a free mucochondral graft for a lower lid defect between April 2013 and October 2020. Patients were discharged shortly after surgery and were expected to visit the outpatient clinic periodically for 12 months. RESULTS: The causes of lower eyelid defects were malignancy, trauma, foreign body granuloma, and other causes. Four patients reported complications, including 2 cases of chemosis, 1 case of a hematoma, and 1 case of corneal abrasion, who reportedly performed well after 2 weeks of conservative therapy. No patient required revision during the average follow-up period. CONCLUSIONS: Customized reconstruction demonstrated a better aesthetic reconstruction of the lower eyelid. This method represents a good option for reconstructing lower lid defects.

Introduction of Deep Learning-Based Infrared Image Analysis to Marginal Reflex Distance1 Measurement Method to Simultaneously Capture Images and Compute Results: Clinical Validation Study.

Marginal reflex distance1 (MRD1) is a crucial clinical tool used to evaluate the position of the eyelid margin in relation to the cornea. Traditionally, this assessment has been conducted manually by plastic surgeons, ophthalmologists, or trained technicians. However, with the advancements in artificial intelligence (AI) technology, there is a growing interest in the development of automated systems capable of accurately measuring MRD1. In this context, we introduce novel MRD1 measurement methods based on deep learning algorithms that can simultaneously capture images and compute the results. This prospective observational study involved 154 eyes of 77 patients aged over 18 years who visited Chungnam National University Hospital between 1 January 2023 and 29 July 2023. We collected four different MRD1 datasets from patients using three distinct measurement methods, each tailored to the individual patient. The mean MRD1 values, measured through the manual method using a penlight, the deep learning method, ImageJ analysis from RGB eye images, and ImageJ analysis from IR eye images in 56 eyes of 28 patients, were 2.64 ± 1.04 mm, 2.85 ± 1.07 mm, 2.78 ± 1.08 mm, and 3.07 ± 0.95 mm, respectively. Notably, the strongest agreement was observed between MRD1_deep learning (DL) and MRD1_IR (0.822, p < 0.01). In a Bland-Altman plot, the smallest difference was observed between MRD1_DL and MRD1_IR ImageJ, with a mean difference of 0.0611 and ΔLOA (limits of agreement) of 2.5162, which was the smallest among all of the groups. In conclusion, this novel MRD1 measurement method, based on an IR camera and deep learning, demonstrates statistical significance and can be readily applied in clinical settings.

Smartphone-Based LiDAR Application for Easy and Accurate Wound Size Measurement.

The accurate assessment of wound size is a critical step in advanced wound care management. This study aims to introduce and validate a Light Detection and Ranging (LiDAR) technique for measuring wound size. Twenty-eight wounds treated from December 2022 to April 2023 at the Chungnam National University Hospital were analyzed. All the wounds were measured using three techniques: conventional ruler methods, the LiDAR technique, and ImageJ analysis. Correlation analysis, linear regression, and Bland-Altman plot analysis were performed to validate the accuracy of the novel method. The measurement results (mean ± standard deviation) obtained using the ruler method, LiDAR technique, and ImageJ analysis were 112.99 ± 110.07 cm2, 73.59 ± 72.97 cm2, and 74.29 ± 72.15 cm2, respectively. The Pearson correlation coefficient was higher for the LiDAR application (0.995) than for the conventional ruler methods (mean difference, -5.0000 cm2), as was the degree of agreement (mean difference, 38.6933 cm2). Wound size measurement using LiDAR is a simple and reliable method that will enable practitioners to conveniently assess wounds with a flattened and irregular shape with higher accuracy. However, non-flattened wounds cannot be assessed owing to the technical limitations of LiDAR.

The Effect of Botulinum Toxin A on NADPH oxidase system and Ischemia Reperfusion Injury.

BACKGROUND: While studies aimed at overcoming ischemia-reperfusion (IR) injury using various materials are becoming popular, studies using botulinum toxin type A (BoNTA) are still limited. This study tested the hypotheses that BoNTA can protect flaps from IR injury by inhibiting the NADPH oxidase system and suppressing ROS (reactive oxygen species) production. MATERIAL AND METHODS: The subjects were Sprague-Dawley rats (n = 76). In 4 rats, the effects of different dose of BoNTA on superoxide production was evaluated through lucigenin enhanced chemiluminescence assay (LECL) using SD rats' thoracic aorta ring. In 60 SD rats, The BoNTA and normal saline-pretreated superficial inferior epigastric artery (SIEA) flaps were clamped for 0, 1, and 4 hours, and reperfused. On the 5th day after the opeartion, well-maintained flaps were grossly inspected, survival rates were analyzed, and histological analysis was also performed. In 12 rats, after making IR injury through the same model, SIEA flap segments and femoral vessels were obtained, and ROS production was evaluated through LECL and dihydroethidium (DHE) staining. RESULTS: In LECL, the experimental group produced a smaller amount of superoxide than the control group through NADPH oxidase inhibition (p < .05). There was no significant difference between the experimental and control group in the 0, and 1 hour IR groups, but the experimental group (90%) showed a higher survival rate than the control group (60%) in the 4 hours IR group (p = .028). In the measurement of ROS production through LECL and DHE staining, there was no significant difference in the 0, and 1 hour IR groups, but a significant difference was shown in the 4 hours IR group in both the SIEA flaps and femoral vessels (p < .05). SUMMARY: This study verified hypothesis that BoNTA can protect flaps from IR injury by inhibiting the NADPH oxidase system and suppressing ROS production. Based on this research model, future research should be expanded into studies on subtypes or subunits of NADPH oxidase, and the findings from the present study are expected to contribute and lead to clinical studies on BoNTA, which has already been proven to be clinically safe.

Mandible Angle Resection with the Retroauricular Approach.

Square-shaped and large moon-shaped faces are commonly observed in Asians, and the contour of the mandible is associated with the shape of the lower part of the face. Mandible contouring surgery is performed to create a softer impression for East Asians. Currently, most surgeries are performed using an intraoral approach. External approaches have not been cosmetically attempted because of possible damage to the facial nerve and visible scarring and have been limited to mandible bone fracture reduction. This study included 42 patients who underwent mandibular angle reduction via classical intraoral incision and retroauricular incision between April 2019 and October 2021. Clinical outcomes were assessed using the Global Aesthetic Improvement Scale and Visual Analog Scale. Surgery was successful in all cases, with no significant complications. An appropriate mandibular contour was achieved postoperatively. All patients were satisfied with the outcome. Some patients experienced short-term complications, such as hematoma and wound disruption of the skin above the incision line. However, these improved within 3 weeks, and no serious long-term complications were observed. Mandible angle resection with the retroauricular approach is a promising alternative for patients, allowing speedy recovery and the resumption of routine daily life.

Reconstruction of complex knee wounds with a distally based gracilis flap and gastrocnemius myocutaneous flap: A case report.

A gastrocnemius muscle flap is a versatile option for covering the proximal one-third of the lower leg and around the knee. On the other hand, it is of limited use in patients with short gastrocnemius muscle or insufficient volume. The authors present a case in which a knee soft tissue defect occurred in a very thin patient and was reconstructed using a gastrocnemius myocutaneous flap and a distally based gracilis flap as a supplementary flap.

Reconstruction of soft tissue defect around knee with thoracodorsal artery perforator flap and muscle-sparing latissimus dorsi flap.

INTRODUCTION: Around the knee reconstruction is challenging for reconstructive surgeons. Several methods have been proposed, including perforator and muscle flaps; however, all have advantages and disadvantages. As the success rate of free-flap surgery increases, reconstruction around the knee using this method is becoming increasingly popular. Nevertheless, there are no large-scale case reports in the previous literature using either a thoracodorsal artery perforator flap (latissimus dorsi (LD) perforator flap) or a muscle-sparing latissimus dorsi (msLD) flap for reconstruction around the knee. In this retrospective report, we describe our clinical experiences and present an algorithm regarding recipient vessel choice in free-flap reconstructive surgery of around the knee defects. PATIENT AND METHODS: Fifty-six cases in which a flap from the lateral thoracic area was used to reconstruct an around the knee defect between January 2016 and March 2022 were reviewed. The patients were aged 18-87 years (mean, 52.13 years), and of the 56 patients, 36 were male and 20 were female. Injuries were caused by trauma, contracture, rheumatoid vasculitis, tumor, infection, burns, sunken deformity, and pressure sores. The 56 cases included 22 with a defect including the knee, 14 with a defect below the knee (7 of the primary below-knee amputation [BKA] and 7 of the secondary BKA), 9 involving the distal medial thigh, 8 involving the distal lateral thigh, 2 involving the popliteal area, and 1 involving the middle thigh. Most cases were reconstructed using a single LD perforator flap or msLD flap. Chimeric or supplementary flaps were used when extensive coverage or dead space obliteration was required. The average size of the defect area was 253.6 cm2 (range: 5 × 6-21 × 39 cm2 ). RESULTS: In the cases, the recipient artery used included the following: descending genicular artery (23), superficial femoral artery (14), descending branch of the lateral circumflex femoral artery (14), anterior tibial artery (2), popliteal artery (2), and posterior tibial artery (1). The recipient vein included the greater saphenous vein (24), descending branch of the lateral circumflex femoral vein (14), superficial femoral vein (7), descending genicular vein (6), anterior tibial vein (2), popliteal vein (2), and posterior tibial vein (1). The average flap size was 281.8 cm2 (range: 4 × 8-35 × 19 cm2 ). All flaps survived; however, seven complications occurred, including 2 partial flap losses, 1 arterial insufficiency, 1 hematoma, 1 minor dehiscence, 1 donor-site graft loss, and 1 short BKA. Normal knee range of motion (121-140°) was observed in 34 patients and 16 showed varying degrees of limited range of motion. Motion was not observed in four patients who underwent knee fusion and could not be evaluated in two patients who underwent above-knee amputation. The mean follow-up duration was 24.6 months (range: 4-72 months). CONCLUSION: The LD perforator flap is ideal for the reconstruction of around the knee defects because it enables a long pedicle, large flap, and chimeric design. The msLD flap is ideal because it enables strong stump support, dead-space obliteration, and infection control. Moreover, since the two flaps are distant from the knee, this method is advantageous in terms of postoperative rehabilitation and there is minimal donor-site morbidity due to the thin nature of the LD muscle. In addition, the flap can be elevated in three positions and the operation can be completed without positional changes in various recipient vessel locations. Based on our experience, we conclude that the LD flap has the potential to be used as widely as or in preference to the anterolateral thigh flap in the reconstruction of around the knee defects.

Alar crease as a donor site for the extension limb of modified nasolabial V-Y advancement flap.

BACKGROUND: The traditional nasolabial V-Y advancement flap is widely used for midface reconstruction, particularly for the lower third of the nose and upper lip, as its color and texture are similar to these areas. However, it provides insufficient tissue to cover large defects and cannot restore the nasal convexity, nasal ala, and adjacent tissues. The purpose of this study is to investigate the modified nasolabial V-Y advancement flap with extension limbs the along alar crease for the reconstruction of complex midface defects. METHODS: A retrospective analysis of 18 patients, who underwent reconstruction with the modified nasolabial V-Y advancement flap, was performed between September 2014 and December 2022. An extension limb was added along the alar crease, adjacent to the defect area, and was hinged down as a transposition flap at the end of the advancement flap. RESULTS: The extension limb along the alar crease successfully covered large and complicated defects, including those of the ala, the alar rim, the alar base, the nostrils, and the upper lip, with minor complications. CONCLUSION: The alar crease is a good donor site for the reconstruction of large and complex nasal and upper lip defects.

Designing with relaxed skin tension line in perforator-based island flap for sacral sore reconstruction: A STROBE-compliant observational study.

Many various types of operative techniques have been performed used to treat make-up for sacral defects. Perforator-based flaps with flap transposition, but achieving an optimal flap design and tension-free flap closure without skeletonizing the perforator requires a great deal of clinical experience. In this study, we demonstrate perforator selection based on considerations of the relaxed skin tension line (RSTL), which has proven to be a suitable method of achieving an efficient flap design that enables primary closure. Twenty-five perforator-based flap procedures were performed on 25 patients at a single institution from February 2018 to January 2021. The medical records of patients were retrospectively reviewed. Twenty-three flaps survived completely. Two flaps developed partial tip necrosis but recovered after secondary healing, and 1 patient developed temporary congestion, which resolved spontaneously. No recipient or donor site recurrence or dehiscence was identified during follow-up. We report our clinical experiences of perforator-based flap use in the sacral region. When selecting an appropriate perforating vessel, 2 important points should be considered, that is, a flap long axis parallel to RSTLs and defect shape. According to the method presented in this paper, perforator-based flaps can be transposed safely and easily with few complications and serve as useful practice models to cover sacral defects.

Aesthetic Removal of Foreign Body Granulomas of Forehead Via Pretrichial Approach.

ABSTRACT: In the field of plastic surgery, various filler types have been developed, which are widely used for cosmetic or reconstruction purposes. However, unregulated substances often injected by unlicensed practitioners may cause difficult-to-treat side effects, such as foreign body granulomas. Since the forehead is an exposed area and the lesions are likely extensive, complete surgical removal with inconspicuous scar can be difficult. In addition, pharmacological treatments, such as steroids, have only a temporary effect. The authors report successful cases of foreign body removal combined with subcutaneous forehead lift via a pretrichial approach for cosmetic satisfaction.Ten patients who had received illegal filler injections that resulted in chronic granulomas on the forehead were studied. The granulomas were confirmed using sonography, and simultaneous foreign body removal and subcutaneous forehead lifts using pretrichial incisions were planned. For the surgical method, the forehead flap was carefully elevated to a uniform thickness in the subcutaneous plane via a pretrichial incision, and the foreign body was removed, paying attention to the forehead contour and nerve damage; excess skin was excised from the top of the flap to tighten the remaining skin on the forehead.None of the patients developed complications, such as skin necrosis, infection, hematoma, or wound dehiscence, during the follow-up period. The functional and aesthetic outcomes were satisfactory in all the patients.The subcutaneous forehead lift via a pretrichial incision seems to facilitate foreign body removal and improve the forehead deformity by tightening the remaining skin.

Zwitterionic polydopamine coatings suppress silicone implant-induced capsule formation.

A synthetic zwitterionic dopamine derivative (ZW-DOPA) containing both catechol and amine groups was recently shown to exhibit excellent antifouling activity on marine surfaces. Here, we have extended these analyses to investigate the effects of ZW-DOPA coating on silicone implants. Successful formation of ZW-DOPA coatings on silicone implants was confirmed based on a combination of decreased static water contact angles on silicone implants, evidence of new peaks at 400.2 (N 1s), 232.2 (S 2s), and 168.0 (S 2p) eV, and increased quantitative atomic composition of C 1s with a concurrent decrease of Si 2p. Anti-biofilm formation assays revealed that ZW-DOPA coating prevented biofilm formation on silicone at a non-lethal concentration (0.5 mg mL-1). Capsule formation was also significantly inhibited by ZW-DOPA coating in vivo and the differentiation of fibroblasts into myofibroblasts was significantly suppressed. Together, these data suggest that silicone implants coated with ZW-DOPA may prevent capsular contracture after insertion when used in breast surgery.

Reconstruction of Sacral Pressure Ulcer Using a Modified Parasacral Perforator-Based Flap (Maple Leaf Design): An Easier Method for Beginners.

Background. Many different operative options have been used to cover sacral defects. Perforator flap enables wide defect reconstruction with long pedicle and a large arc of rotation while preserving gluteus maximus muscle, but the risk of vessel injury can jeopardize flap survival. Perforator-based flap, the flap transposed without skeletonization of the perforator, requires much experience to be perfect in flap design to achieve tension-free closure. Methods. Fourteen modified parasacral perforator-based flap procedures were carried out on 14 patients. The records of patients at Chungnam National University Hospital from February 2017 to January 2020 were retrospectively reviewed. Results. All 14 flaps survived completely. One patient developed localized hematoma, and another presented with latent seroma. No donor or recipient site dehiscence or recurrence occurred during follow-up. Conclusion. We present our experience of a parasacral perforator-based flap with modified design of bilobed flaps. It could be performed easily and safely with less wound dehiscence and serve as a good practice model for young surgeons to cover small to moderately sized defects.

Reconstruction of the Lower Leg With Percutaneous Aponeurotomy and Lipofilling: A Case Report.

Soft tissue loss in the lower leg presents a challenge for reconstructive surgeons. When a defect is large, free flap transfer provides a well-established method, but local flaps are more convenient for small to moderately sized soft tissue defects. When a defect is very small, even local flaps are too invasive, leave additional scar, and cause bulky flaps. We present our case aiming to underline the usefulness of percutaneous aponeurotomy and lipofilling in a small lower leg defect with several advantages.

Proper Choice of Vessels for Supermicrosurgery Training: An Experimental Animal study.

BACKGROUND: Reconstruction using supermicrosurgery, a technique of microneurovascular anastomosis for smaller vessels (< 0.8 mm), has become popular. Experimental animal studies for supermicrosurgery training have been reported; however, there have been few studies performed according to vessel diameter and pedicle length. In this study, the external diameters of four vessels (femoral, superficial epigastric, axillary, and common thoracic) and pedicle length of two flaps (superficial epigastric and common thoracic-long thoracic) were measured. METHODS: The inguinal and pectoral regions of Sprague-Dawley rats (n = 19) were dissected anatomically, and the external diameters of the four vessels were measured (right and left, artery and vein measured separately). After elevating the superficial epigastric and common thoracic-long thoracic flaps, the pedicle length of the flaps was also measured. RESULTS: Among the 16 vessels examined, the external diameters of 11 and 5 vessels were above and below 0.8 mm, respectively. The external diameters of the superficial epigastric vessel and common thoracic vessel (both arteries and veins) were below 0.8 mm. The external diameters of the femoral and axillary vessels (veins) were above 0.8 mm. The length of the common thoracic-long thoracic pedicle was approximately10 mm longer than that of the superficial epigastric pedicle. CONCLUSIONS: The external diameters of the superficial epigastric vessel and common thoracic vessel are small enough for supermicrosurgery training. The pedicle lengths of both the superficial epigastric and common thoracic-long thoracic flaps are sufficient to perform free flap experiments. Supermicrosurgical free flaps using these two vessels and a study of the physiology and pharmacology of the flaps will likely be possible in the future.

Availability and Safety of Osteotomy in Esthetic Rhinoplasty of East Asian Patients.

OBJECTIVE: East Asians usually have short and flat noses and broad nasal bones. Therefore, rhinoplasty with dorsal augmentation and nasal osteotomy is often required. However, many surgeons are wary of performing nasal osteotomy in conjunction with augmentation with silicone. The authors sought to evaluate the availability and safety of osteotomy in esthetic rhinoplasty of East Asian patients. METHODS: In a clinical study, a retrospective chart review was performed for 227 patients who had undergone nasal osteotomy (paramedian oblique osteotomy plus percutaneous lateral osteotomy) and dorsal augmentation with silicone. Patient satisfaction after surgery was evaluated by the Rhinoplasty Outcome Evaluation test. In addition, a cadaveric study was conducted in which 5 fresh cadavers received different osteotomies on each side of the nose (right side: paramedian oblique and percutaneous lateral osteotomy; left side: medial oblique and intranasal continuous lateral osteotomy). RESULTS: In the clinical study, patients were satisfied with the outcome after esthetic rhinoplasty with nasal osteotomy (paramedian oblique osteotomy plus percutaneous lateral osteotomy) and augmentation with silicone. The results revealed a low complication rate. The average Rhinoplasty Outcome Evaluation test score significantly increased (P < 0.001), with 91.2% of patients scoring their postoperative result better than "good." In the cadaveric study, stability was greater when paramedian oblique and percutaneous lateral osteotomy was performed. CONCLUSIONS: Paramedian oblique and percutaneous lateral osteotomy is effective for reducing broad nasal bones, thus providing a stable framework and a reliable method for achieving a good outcome when augmentation with silicone is performed simultaneously.

Effects of Growth Factors From Platelet-Rich Fibrin on the Bone Regeneration.

Platelet-rich fibrin (PRF) has simple manufacturing process without risk of immunologic rejection or infection by additional materials. This study was designed to investigate the effects of platelet-derived growth factors and transforming growth factors-ß in PRF on the proliferation and differentiation of osteoblasts. The authors analyzed platelet-derived growth factors and transforming growth factors-ß in normal human serum (NHS) and PRF by enzyme-linked immunosorbent assay quantitatively and those in PRF group were significantly increased when compared with NHS. After harvesting osteoblasts from iliac bone, the authors added 10% fetal bovine serum, 10% NHS, and 3% PRF to osteoblasts, respectively and incubated for 24, 48, 72 hours. For analysis of osteoblast proliferation and differentiation, the authors measured DNA synthesis by [3H]-thymidine isotope activity, protein synthesis by sulforhoamine B assay and those were increased according to elapsed time in all groups, but they were significantly increased in 3% PRF. The authors measured alkaline phosphatase activity of osteoblasts, it was increased according to elapsed to time in all groups, but significantly increased in 72 hours. In conclusion, application of PRF to bone defect sites may have an enhanced effect of bone regeneration with low risk of complications, and relatively simple manufacturing process.

Peroneal Flap: Clinical Application and Cadaveric Study.

BACKGROUND: The goal of this study was to investigate the anatomy of the peroneal artery and its perforators, and to report the clinical results of reconstruction with peroneal artery perforator flaps. METHODS: The authors dissected 4 cadaver legs and investigated the distribution, course, origin, number, type, and length of the perforators. Peroneal artery perforator flap surgery was performed on 29 patients. RESULTS: We identified 19 perforators in 4 legs. The mean number of perforators was 4.8 per leg, and the mean length was 4.8 cm. Five perforators were found proximally, 9 medially, and 5 distally. We found 12 true septocutaneous perforators and 7 musculocutaneous perforators. Four emerged from the posterior tibia artery, and 15 were from the peroneal artery. The peroneal artery perforator flap was used in 29 patients. Retrograde island peroneal flaps were used in 8 cases, anterograde island peroneal flaps in 5 cases, and free peroneal flaps in 16 cases. The mean age was 59.9 years, and the defect size ranged from 2.0 cm×4.5 cm to 8.0 cm×8.0 cm. All the flaps survived. Five flaps developed partial skin necrosis. In 2 cases, a split-thickness skin graft was performed, and the other 3 cases were treated without any additional procedures. CONCLUSIONS: The peroneal artery perforator flap is a good alternative for the reconstruction of soft tissue defects, with a constant and reliable vascular pedicle, thin and pliable skin, and the possibility of creating a composite tissue flap.

Effect of Botulinum Toxin Type A on TGF-ß/Smad Pathway Signaling: Implications for Silicone-Induced Capsule Formation.

BACKGROUND: One of the most serious complications of breast surgery using implants is capsular contracture. Several preventive treatments have been introduced; however, the mechanism of capsule formation has not been resolved completely. The authors previously identified negative effects of botulinum toxin type A on capsule formation, expression of transforming growth factor (TGF)-ß1, and differentiation of fibroblasts into myofibroblasts. Thus, the authors investigated how to prevent capsule formation by using botulinum toxin type A, particularly by means of TGF-ß1 signaling, in human fibroblasts. METHODS: In vitro, cultured human fibroblasts were treated with TGF-ß1 and/or botulinum toxin type A. Expression of collagen, matrix metalloproteinase, and Smad was examined by Western blotting. The activation of matrix metalloproteinase was observed by gelatin zymography. In vivo, the effect of botulinum toxin type A on the phosphorylation of Smad2 in silicone-induced capsule formation was evaluated by immunocytochemistry. RESULTS: In vitro, the phosphorylation of Smad2 was inhibited by botulinum toxin type A treatment. The expression levels of collagen types 1 and 3 were inhibited by botulinum toxin type A treatment, whereas those of matrix metalloproteinase-2 and matrix metalloproteinase-9 were enhanced. Gelatin zymography experiments confirmed enhanced matrix metalloproteinase-2 activity in collagen degradation. In vivo, botulinum toxin type A treatment reduced capsule thickness and Smad2 phosphorylation in silicone-induced capsules. CONCLUSION: This study suggests that botulinum toxin type A plays an important role in the inhibition of capsule formation through the TGF-ß/Smad signaling pathway. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, V.