Risk Factors of Tissue Expander Malposition in Two-Stage Breast Reconstruction

Risk Factors of Tissue Expander Malposition in Two-Stage Breast Reconstruction | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Risk Factors of Tissue Expander Malposition in Two-Stage Breast Reconstruction Eisei Yoshizawa, Makoto Shiraishi, Kanako Danno, Chihena Hansini Banda, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6814878/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background Tissue expander (TE) malposition is a notable complication in two-stage breast reconstruction, potentially leading to breast asymmetry and diminished patient satisfaction. Smooth-surface TEs are hypothesized to be more susceptible due to reduced tissue adherence. This study aimed to determine the incidence and risk factors associated with TE malposition and to discuss potential preventative strategies and corrective techniques. Methods A retrospective cohort study was conducted, reviewing data from 32 consecutive patients who underwent TE breast reconstruction at Mie University Hospital (Japan) between January 2020 and December 2021. The study collected demographic characteristics, surgical details, TE parameters, and injection volumes. Statistical analysis was performed using SPSS (ver. 29.0) to identify significant risk factors for TE malposition. Results The overall incidence of TE malposition was 9.4% (3/32). Statistical analysis revealed that younger age (39.7 ± 0.64 years vs. 49.9 ± 7.29 years, p < 0.001), the use of inframammary fold (IMF) plasty (33.3% vs 3.4%; p = 0.04), larger TE size, and higher initial injection volume (253.3 ± 128.6 ml vs. 130.7 ± 69.3 ml, p = 0.01) were significantly associated with TE malposition. Regression analyses identified younger age (p = 0.039) and larger TE size (p = 0.004) as independent predictors of TE malposition. Conclusions Younger age, the application of IMF plasty, larger TE size, and higher first injection volume are significant risk factors for TE malposition in two-stage breast reconstruction. These findings may inform surgical decision-making and postoperative care, potentially reducing the incidence of TE malposition. Breast reconstruction Tissue Expander Breast Implant Malposition Figures Figure 1 Figure 2 Introduction Breast reconstruction significantly improves patients' health-related quality of life, including satisfaction with appearance and enhanced physical, psychosocial, and sexual well-being following breast cancer surgery [ 1 – 6 ]. Alloplastic breast reconstruction, utilizing TEs and implants, is a prevalent method, accounting for over 65% of all breast reconstructions [ 7 ]. Tissue expander (TE) malposition is a clinically relevant complication in two-stage breast reconstruction, potentially leading to implant malposition, breast asymmetry, and reduced patient satisfaction. Both smooth- and textured-surface TEs can be affected, with smooth-surface TEs hypothesized to be more vulnerable due to their limited surface area and reduced tissue adherence. The reported incidence of malposition with smooth-surface TEs ranges from 2.9–13.6% [ 8 – 9 ]. Malposition can result in skin expansion in unintended areas, leading to disfigurement of the reconstructed breast, the need for additional procedures, and increased financial burden. Limited data exist specifically addressing TE malposition as a complication. The purpose of this study was to investigate the incidence of TE malposition, identify associated risk factors, and discuss strategies to prevent and manage this complication. Materials and Methods Subjects and Experimental Design This retrospective cohort study included all consecutive patients undergoing breast operations between January 2020 and December 2021 at Mie University Hospital in Tsu, Japan. Inclusion criteria were: (1) age ≥ 18 years, (2) undergoing first-time post-mastectomy breast reconstruction using a TE as the initial stage, and (3) absence of surgical complications that would limit long-term follow-up. Exclusion criteria included severe neurological or psychiatric disorders affecting comprehension. All participants provided written informed consent. The study was approved by the local research ethics committee (Mie University IRBMED Number H2022-084) and was conducted in accordance with the Declaration of Helsinki. Data Collection and Measurements Demographic and clinical data were collected prospectively, including: age, body mass index (BMI), follow-up duration, laterality, type of operation, cancer stage, history of radiotherapy or chemotherapy, breast surgery type, TE type, inframammary fold (IMF) plasty, tab suture, use of absorbable sutures, TE duration, first injection volume, and total injection volume. Ratios of first and total injection volume to BMI were also calculated. To minimize selection bias, two independent researchers reviewed and finalized the list of included studies, resolving any discrepancies through consensus. Statistical Analysis Data were analyzed using SPSS (ver. 29.0). Continuous variables with a normal distribution were presented as mean ± standard deviation (SD), and categorical variables as number (percentage). The Chi-square test was used to compare categorical variables. Adjusted standardized residuals were calculated to identify cells with significantly higher or lower than expected frequencies. Variables with a significance level of P < 0.05 were included in multivariate analysis. Risk factors associated with TE malposition were identified using linear stepwise regression analysis. A multiple linear regression model was constructed to explore risk factors for postoperative pain. Statistical significance was defined as a two-tailed P < 0.05. Results Study Participants The study cohort comprised 32 subjects with a mean age of 49.0 ± 7.56 years, a mean BMI of 23.1 ± 4.0 kg/m2, and a mean follow-up period of 12.4 ± 5.0 months. Breast cancer laterality was equally distributed. The majority of cases were Stage I (43.8%) and Stage II (43.8%). A minority of patients (12.5%) received chemotherapy, and none received radiotherapy. Types of breast surgery included total mastectomy (59.4%), skin-sparing mastectomy (15.6%), and nipple-sparing mastectomy (21.9%). Sentinel lymph node biopsy was performed in 87.5% of cases, and axillary lymph node dissection in 9.4%. IMF plasty, tab suture, and use of absorbable sutures were performed in 6.3%, 65.6%, and 34.4% of cases, respectively. The mean TE duration was 10.1 ± 3.50 months. Mean first and total injection volumes were 142.2 ± 82.0 ml and 320.2 ± 117.5 ml, respectively. Mean first and total injection volume/BMI ratios were 6.2 ± 3.5 and 14.0 ± 4.9, respectively. Detailed participant demographics are shown in Table 1. Comparison of malposition and non-malposition groups Three cases experienced TE malposition (Table 2). The mean age was significantly lower in the malposition group (39.7 ± 0.64 years) compared to the non-malposition group (49.9 ± 7.29 years; p < 0.001). NSM and Mx-15 occurred more frequently, and Bt and Mx-14 occurred less frequently in the malposition group compared to expected frequencies. IMF plasty was significantly more common in the malposition group (33.3% vs 3.4%; p = 0.04). The first injection volume was significantly higher in the malposition group (253.3 ± 128.6 ml) than in the non-malposition group (130.7 ± 69.3 ml; p = 0.01). First and total injection volume/BMI ratios were also significantly higher in the malposition group (11.0 ± 3.81 and 19.7 ± 3.75, respectively) compared to the non-malposition group (5.72 ± 3.11; p = 0.01 and 13.4 ± 4.69; p = 0.03, respectively). No other variables differed significantly between the groups. Risk Factors Associated with TE Malposition Regression analyses revealed that younger age (β -0.322, 95% confidence interval [CI] -0.025 to -0.001, p = 0.039) and larger TE size (β 0.469, 95% CI 0.043 to 0.201, p = 0.004) were significantly associated with a higher incidence of TE malposition (Table 3). Cases Case 1 A 39-year-old female patient (height: 162.5 cm, weight: 50.3 kg, BMI: 18.7) was diagnosed with invasive ductal carcinoma in the C region of the left breast, staged as T1cN0M0. The patient underwent left NSM, SNB, and TE insertion. A smooth-type tissue expander (Natrelle® 133S MV-12-T, Allergan Plc, Madison, USA) was used. The TE tab was sutured and fixed using 3 − 0 VICRYL® (polyglactin 910, Ethicon Inc., Somerville, NJ, USA). The inframammary fold (IMF) was not reconstructed during the initial surgery. The initial saline fill volume was 160 ml. The patient did not receive adjuvant chemotherapy, radiotherapy, or hormonal therapy. During monthly outpatient follow-up visits for saline injections, TE malposition was observed at 4 months post-surgery. At this point, the saline fill volume had reached 300 ml, and physical examination revealed inferior displacement of the left IMF by 3 cm compared to the contralateral side. At the patient’s request, breast reconstruction was performed using a profunda artery perforator (PAP) flap seven months after the initial surgery. This procedure successfully addressed the TE malposition. No additional corrective surgeries were required, and the patient has been followed up without complications (Fig. 1 ). Case 2 A 39-year-old female patient (height: 164.6 cm, weight: 70.4 kg, BMI: 26.0) was diagnosed with non-invasive ductal carcinoma in the C region of the right breast, staged as TisN0M0. The patient underwent right SSM, SNB, and TE insertion. A smooth-type tissue expander (Natrelle® 133S MV-14-T, Allergan Plc, Madison, USA) was used. The TE tab was sutured and fixed using 3 − 0 VICRYL® (polyglactin 910, Ethicon Inc., Somerville, NJ, USA). The IMF was created using Stratafix® Knotless Tissue Control Device (Ethicon Inc, Somerville, NJ, USA). The initial saline fill volume was 400 ml. The patient did not receive adjuvant chemotherapy, radiotherapy, or hormonal therapy. During monthly outpatient follow-up visits, TE malposition was observed at 2 months post-surgery, when the saline fill volume had reached 520 ml. At the patient’s request, the TE was replaced with a silicone implant (Natrelle® JSSM-345) nine months after the initial surgery. This procedure successfully addressed the TE alposition. No additional corrective surgeries were required, and the patient has been followed up without complications (Fig. 2 ). Discussion This retrospective study identified several factors associated with TE malposition following breast reconstruction: younger age and larger TE size were significant risk factors. To our knowledge, limited research specifically addresses TE malposition. Fairchild et al. reported a 2.3% incidence of malposition with smooth-surface TEs [ 8 ]. McLaughlin et al. found that smooth TEs had a 40-fold higher risk of malposition compared to textured TEs (13.6% vs 0.3%; P < 0.001) [ 9 ]. Spear, et al. reported that the incidence rate of implant malposition of Natrelle® Round Silicone Breast Implants was 2.3% [ 10 ]. Studies on implant malposition have identified older age (OR 1.05, 95% CI 1.02–1.07), BMI < 25 (OR 1.64, 95% CI 1.00-2.70), and bilateral reconstruction (OR 13.41, 95% CI 8.50-21.16) as risk factors [ 11 ]. Our findings partially align with this, as younger patients with lower weight tended to experience TE malposition. In Japan, textured-surface TEs were historically favored due to a lower incidence of capsular contracture. However, following the recognition of breast implant-associated anaplastic large cell lymphoma (BIA-ALCL), textured TEs such as Natrelle® 133 (Allergan Plc, Madison, USA) were removed from Japanese insurance coverage [ 12 ]. Currently, smooth-surface TEs, such as the Natrelle® 133S (Allergan Plc, Madison, USA) are the standard for breast reconstruction. These TEs feature a 360-degree tab orientation for enhanced placement support [ 10 ]. Acellular dermal matrices are not approved for clinical use in Japan as of 2020 [ 13 ]. As a measure of malposition management, a higher prosthesis volume-to-BMI ratio increases the risk of malposition. Within a specific volume range (20 × BMI – 300 ± 100 mL), the incidence of malposition is significantly lower [ 11 ]. Additionally, multi-stabilizing surgical techniques—such as firm tab fixation, strict pocket control, and careful selection of suture material—are reported to reduce the risk of expander malposition and achieve favorable outcomes [ 8 , 14 – 15 ]. Given the multifactorial nature of positional abnormalities, optimal results require accurate preoperative counseling and individualized surgical planning. Surgeons should comprehensively consider each patient’s profile (including age, body type, comorbidities, smoking history, and planned adjuvant therapy) and adjust surgical strategies accordingly (implant type, size, placement site, and fixation method). For example, in elderly patients or those with low BMI, artificial breasts tend to sag more easily due to insufficient soft tissue support to counteract gravity and pectoral muscle activity. Recognizing these complex interactions underscores the importance of a patient-centered, individualized approach, rather than focusing on a single cause. Surgeons must therefore select the optimal technique based on each patient’s unique risk factors. [ 11 ] In cases where malposition was identified, reoperation was not always required, and favorable outcomes were achieved with two-stage reconstruction. Malposition can reduce patient satisfaction and may cause morphological abnormalities, such as unnatural appearance or asymmetry between the breasts. However, not all cases are clinically significant. For example, despite reports of 40-fold higher malposition rates with smooth-type TEs, there were cases where reoperation was unnecessary [ 9 ]. The present case series also suggests that malposition can be observed even in cases with subclinical symptoms or only slight displacement. Distinguishing between minor and significant malposition is crucial to avoid unnecessary surgical intervention. In conclusion, preventing malposition requires meticulous surgical planning and technique, as well as individualized risk assessment and counseling. Ongoing evaluation of surgical outcomes and further studies are needed to establish standardized guidelines for the prevention and management of TE malposition. This study has several limitations. First, the relatively small sample size may restrict the statistical power and generalizability of the findings. Second, although we attempted to mitigate selection and search biases through independent review and consensus, these biases could not be fully excluded. Additionally, the homogeneity of the study population, resulting from the single-center design, may further limit the generalizability of our results. However, this single-center approach enabled the implementation of a standardized postoperative pain management protocol. To our knowledge, this study represents one of the first analyses of long-term postoperative malposition following breast surgery in Japanese patients. Declarations Author contributions All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Eisei Yoshizawa, Makoto Shiraishi and Ryohei Ishiura. The first draft of the manuscript was written by Eisei Yoshizawa and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript. Acknowledgements Compliance with Ethical standards Data availability Data for this study are available upon request. Funding The authors received no funding for data collection or preparation of the manuscript. Conflict of interest The authors declare that they have no conflict of interest. Ethical Approval All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. This article does not contain any studies with animals performed by any of the authors. Informed consent Informed consent was obtained from all individual participants included in the study. Additional informed consent was obtained from all individual participants for whom identifying information is included in this article. References Matros E, Albornoz CR, Razdan SN, Mehrara BJ, Macadam SA, Ro T, et al. Cost-effectiveness analysis of implants versus autologous perforator flaps using the BREAST-Q. Plast Reconstr Surg. 2015;135:937-946. doi:10.1097/PRS.0000000000001134. Hu ES, Pusic AL, Waljee JF, Kuhn L, Hawley ST, Wilkins E, et al. Patient-reported aesthetic satisfaction with breast reconstruction during the long-term survivorship Period. Plast Reconstr Surg. 2009;124:1-8. doi:10.1097/PRS.0b013e3181ab10b2. Dean C, Chetty U, Forrest AP. Effects of immediate breast reconstruction on psychosocial morbidity after mastectomy. Lancet 1983;1:459-62. doi:10.1016/s0140-6736(83)91452-6. Shiraishi M, Sowa Y, Inafuku N. Long-term survey of sexual well-being after breast reconstruction using the BREAST-Q in the Japanese population. Asian J Surg. 2022;46:150-155. doi:10.1016/j.asjsur.2022.02.007. Shiraishi M, Sowa Y, Tsuge I, Kodama T, Inafuku N, Morimoto N. Long-Term Patient Satisfaction and Quality of Life Following Breast Reconstruction Using the BREAST-Q: A Prospective Cohort Study. Front Oncol. 2022;12:815498. doi:10.3389/fonc.2022.815498. Shiraishi M, Sowa Y, Tomita K, Terao Y, Satake T, Muto M, et al. Performance of Artificial Intelligence Chatbots in Answering Clinical Questions on Japanese Practical Guidelines for Implant-based Breast Reconstruction. Aesthetic Plast Surg. 2025;49:1947-1953. doi:10.1007/s00266-024-04515-y. Cho MJ, Farhadi RV, Nash DW, Kaleeny J, Povoski SP, Chao AH. The current use of tissue expanders in breast reconstruction: device design, features, and technical considerations. Expert Rev Med Devices. 2024;21:27-35. doi: 10.1080/17434440.2023.2288911. Fairchild B, Ellsworth W, Selber JC, Bogue DP, Zavlin D, Nemir S, et al. Safety and Efficacy of Smooth Surface Tissue Expander Breast Reconstruction. Aesthet Surg J. 2020;40: 53-62. doi: 10.1093/asj/sjy199. McLaughlin C, Hughes AJ, Parham CS, Fritsche M, Potochny JD, Kunselman A, et al. Smooth Versus Textured Tissue Expander Breast Reconstruction: Complications and Efficacy. Ann Plast Surg. 2022;88:S288-S292. doi: 10.1097/SAP.0000000000003193. Spear SL, Murphy DK; Allergan Silicone Breast Implant U.S. Core Clinical Study Group. Natrelle round silicone breast implants: Core Study results at 10 years. Plast Reconstr Surg. 2014;133:1354-1361. doi:10.1097/PRS.0000000000000021. Fracol M, Qiu CS, Chiu WK, Feld LN, Shah N, Kim JYS. Lateral and Inferior Implant Malposition in Prosthetic Breast Reconstruction: Incidence and Risk Factors. Plast Reconstr Surg Glob Open. 2020;8:e2752. doi:10.1097/GOX.0000000000002752. Ishii N. Current status of pre- or subpectoral breast reconstruction in Japan. Gland Surg. 2023;12:1786-1793. doi:10.21037/gs-23-221. Okumura S, Hyodo I, Iwata H, Kamei Y. Immediate one-stage implant-based breast reconstruction without the use of acellular dermal matrix in Japanese breast cancer patients. Breast Cancer. 2020;27:759-764. doi:10.1007/s12282-020-01073-4. Scheflan M, Colwell AS. Tissue Reinforcement in Implant-based Breast Reconstruction. Plast Reconstr Surg Glob Open. 2014;2:e192. doi:10.1097/GOX.0000000000000140 Nelson JA, Rubenstein RN, Vorstenbosch J, Haglich K, Poulton RT, McGriff D, et al. Textured versus Smooth Tissue Expanders: A Comparison of Complications in 3526 Breast Reconstructions. Plast Reconstr Surg. 2024;153:262e-272e. doi:10.1097/PRS.0000000000010600 Tables Tables are available in the Supplementary Files section. Supplementary Files Table1.pdf Table 1. Comparison of demographic and clinical characteristics between malposition and non-malposition cases in tissue expander breast reconstruction (n = 32) BMI: Body Mass Index; TE: Tissue Expander; Bt: Total mastectomy; SSM: Skin Sparing Mastectomy; NSM: Nipple Sparing Mastectomy; SNB: Sentinel Node Biopsy; Ax: Axillary lymph nodes dissection; IMF: inframammary fold; SD: Standard deviation. Table2.pdf Table 2. Detailed comparison of surgical and postoperative factors between malposition and non-malposition cases in tissue expander breast reconstruction (n = 32) p < 0.05; ** p < 0.01; *** p < 0.001. NA: Not available. ‡ Positive adjusted standardized residual, indicating that the standardized difference between observed count and expected count was higher than expected. † Negative adjusted standardized residual, indicating that the standardized difference between observed count and expected count was lower than expected. BMI: Body Mass Index; TE: Tissue Expander; Bt: Total mastectomy; SSM: Skin Sparing Mastectomy; NSM: Nipple Sparing Mastectomy; SNB: Sentinel Node Biopsy; Ax: Axillary lymph nodes dissection; IMF: inframammary fold; SD: Standard deviation. Table3.pdf Table 3. Multiple stepwise regression analysis of factors associated with malposition of tissue expanders in breast reconstruction BMI: Body Mass Index; TE: Tissue Expander; Bt: Total mastectomy; SSM: Skin Sparing Mastectomy; NSM: Nipple Sparing Mastectomy; SNB: Sentinel Node Biopsy; Ax: Axillary lymph nodes dissection; IMF: inframammary fold; SD: Standard deviation. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6814878","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":468261517,"identity":"50edd8ba-9594-47bc-9e48-5d3e27090367","order_by":0,"name":"Eisei Yoshizawa","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA2ElEQVRIiWNgGAWjYDACZiBO/Gcjxw/iJBQQqyWBLc1YsgHEMCDaKrbDiRsOgBjEaOFnZ3/44AEPc+Lm86sTPzwwYJDnFzuAX4tkM4+xQYIEm/G2G283SwAdZjhzdgJ+LQaHediAKnlkt904uwGkJcHgNgEt9ofZn/9ISJBg3Dzj7OYfRGkxYGYwY0g4YKC4gb93G3G2SBzmMZZIbEgwlrjBu80iwUCCsF/4+48//Piz4b8cf//ZzTd/VNjI80sT0IJkH1ilBLHKwfYdIEX1KBgFo2AUjCQAAJrHQqA/X5rzAAAAAElFTkSuQmCC","orcid":"https://orcid.org/0009-0001-7740-6469","institution":"Aichi Medical University: Aichi Ika Daigaku","correspondingAuthor":true,"prefix":"","firstName":"Eisei","middleName":"","lastName":"Yoshizawa","suffix":""},{"id":468261518,"identity":"d34fb473-7896-4ade-a2bd-5d55a58633b9","order_by":1,"name":"Makoto Shiraishi","email":"","orcid":"","institution":"The University of Tokyo Hospital: Tokyo Daigaku Igakubu Fuzoku Byoin","correspondingAuthor":false,"prefix":"","firstName":"Makoto","middleName":"","lastName":"Shiraishi","suffix":""},{"id":468261519,"identity":"a6b71bd3-98b0-4d5b-bcd1-c4651fbfe394","order_by":2,"name":"Kanako Danno","email":"","orcid":"","institution":"Mie University: Mie Daigaku","correspondingAuthor":false,"prefix":"","firstName":"Kanako","middleName":"","lastName":"Danno","suffix":""},{"id":468261520,"identity":"e05c7993-a756-421a-9328-8ce5763756da","order_by":3,"name":"Chihena Hansini Banda","email":"","orcid":"","institution":"University of Zambia University Teaching Hospital","correspondingAuthor":false,"prefix":"","firstName":"Chihena","middleName":"Hansini","lastName":"Banda","suffix":""},{"id":468261521,"identity":"b8e07f08-9413-4c0a-b7a6-ecf3db576892","order_by":4,"name":"Tomoko Ogawa","email":"","orcid":"","institution":"Mie University: Mie Daigaku","correspondingAuthor":false,"prefix":"","firstName":"Tomoko","middleName":"","lastName":"Ogawa","suffix":""},{"id":468261522,"identity":"b690f235-3ffb-474b-807c-a3bae5cd90a1","order_by":5,"name":"Mitsunaga Narushima","email":"","orcid":"","institution":"Mie University: Mie Daigaku","correspondingAuthor":false,"prefix":"","firstName":"Mitsunaga","middleName":"","lastName":"Narushima","suffix":""},{"id":468261523,"identity":"89c2a134-a005-4f26-8029-1ff9d24a526a","order_by":6,"name":"Hiroshi Furukawa","email":"","orcid":"","institution":"Aichi Medical University: Aichi Ika Daigaku","correspondingAuthor":false,"prefix":"","firstName":"Hiroshi","middleName":"","lastName":"Furukawa","suffix":""},{"id":468261524,"identity":"bb861b7c-72ee-464b-be74-1416c3b193d0","order_by":7,"name":"Ryohei Ishiura","email":"","orcid":"https://orcid.org/0000-0002-8900-0124","institution":"Mie University: Mie Daigaku","correspondingAuthor":false,"prefix":"","firstName":"Ryohei","middleName":"","lastName":"Ishiura","suffix":""}],"badges":[],"createdAt":"2025-06-04 00:02:49","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6814878/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6814878/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":84366548,"identity":"059b405e-12f1-474f-9d21-7f5e1dc2ad63","added_by":"auto","created_at":"2025-06-11 06:09:05","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":8645929,"visible":true,"origin":"","legend":"\u003cp\u003eTissue expander malposition and correction with profunda artery perforator (PAP) flap in a 39-year-old female patient (BMI: 18.7) following left nipple-sparing mastectomy for T1cN0M0 invasive ductal carcinoma. (a-c) Four months post-insertion, showing inferior displacement of the left inframammary fold by 3 cm with 300 ml saline fill. (d-f) Seven months post-initial surgery after PAP flap reconstruction. Lateral and oblique views demonstrating successful correction of malposition without complications.\u003c/p\u003e","description":"","filename":"Fig1.png","url":"https://assets-eu.researchsquare.com/files/rs-6814878/v1/db6d08ceb11ea94271c5e559.png"},{"id":84367096,"identity":"8cd4342d-b679-4e6b-8102-6689977e9ca9","added_by":"auto","created_at":"2025-06-11 06:17:05","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":8284299,"visible":true,"origin":"","legend":"\u003cp\u003eTissue expander malposition and correction with silicone implant in a 39-year-old female patient (BMI: 26.0) following right skin-sparing mastectomy for TisN0M0 non-invasive ductal carcinoma. (a-c) Progressive inferior malposition of tissue expander at 1, 2, and 4 months post-insertion, respectively. Initial fill volume was 400 ml, reaching 520 ml at 2 months. (d-f) Nine months post-surgery, after replacement with Natrelle® JSSM-345 silicone implant. Lateral and oblique views showing successful correction of malposition without complications.\u003c/p\u003e","description":"","filename":"Fig2.png","url":"https://assets-eu.researchsquare.com/files/rs-6814878/v1/1799f34034be69de3cbbf899.png"},{"id":85830829,"identity":"00dd2208-13c5-4fad-8c09-91ed3e052799","added_by":"auto","created_at":"2025-07-02 07:41:15","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":15868134,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6814878/v1/c76b3ff4-b0c1-4f3b-a59c-1fe7b37216b4.pdf"},{"id":84366545,"identity":"3f78b293-90e2-4b4e-8fba-e8cc3b6be855","added_by":"auto","created_at":"2025-06-11 06:09:04","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":96429,"visible":true,"origin":"","legend":"\u003cp\u003eTable 1. Comparison of demographic and clinical characteristics between malposition and non-malposition cases in tissue expander breast reconstruction (n = 32)\u003c/p\u003e\n\u003cp\u003eBMI: Body Mass Index; TE: Tissue Expander; Bt: Total mastectomy; SSM: Skin Sparing Mastectomy; NSM: Nipple Sparing Mastectomy; SNB: Sentinel Node Biopsy; Ax: Axillary lymph nodes dissection; IMF: inframammary fold; SD: Standard deviation.\u003c/p\u003e","description":"","filename":"Table1.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6814878/v1/55b7dabbe63775781cecc774.pdf"},{"id":84366542,"identity":"f3bb2a2f-5263-42f7-a462-a17c9ece9214","added_by":"auto","created_at":"2025-06-11 06:09:04","extension":"pdf","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":109236,"visible":true,"origin":"","legend":"\u003cp\u003eTable 2. Detailed comparison of surgical and postoperative factors between malposition and non-malposition cases in tissue expander breast reconstruction (n = 32)\u003c/p\u003e\n\u003cp\u003ep \u0026lt; 0.05; ** p \u0026lt; 0.01; *** p \u0026lt; 0.001. NA: Not available.\u003cbr\u003e\n‡ Positive adjusted standardized residual, indicating that the standardized difference between observed count and expected count was higher than expected.\u003cbr\u003e\n† Negative adjusted standardized residual, indicating that the standardized difference between observed count and expected count was lower than expected.\u003c/p\u003e\n\u003cp\u003eBMI: Body Mass Index; TE: Tissue Expander; Bt: Total mastectomy; SSM: Skin Sparing Mastectomy; NSM: Nipple Sparing Mastectomy; SNB: Sentinel Node Biopsy; Ax: Axillary lymph nodes dissection; IMF: inframammary fold; SD: Standard deviation.\u003c/p\u003e","description":"","filename":"Table2.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6814878/v1/550d2e8a6465f9e979079ad4.pdf"},{"id":84366533,"identity":"912dd028-3391-409e-a0f0-7e5d2c7216a6","added_by":"auto","created_at":"2025-06-11 06:09:02","extension":"pdf","order_by":3,"title":"","display":"","copyAsset":false,"role":"supplement","size":100957,"visible":true,"origin":"","legend":"\u003cp\u003eTable 3. Multiple stepwise regression analysis of factors associated with malposition of tissue expanders in breast reconstruction\u003c/p\u003e\n\u003cp\u003eBMI: Body Mass Index; TE: Tissue Expander; Bt: Total mastectomy; SSM: Skin Sparing Mastectomy; NSM: Nipple Sparing Mastectomy; SNB: Sentinel Node Biopsy; Ax: Axillary lymph nodes dissection; IMF: inframammary fold; SD: Standard deviation.\u003c/p\u003e","description":"","filename":"Table3.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6814878/v1/ba24fa6a4484eae4deba1e97.pdf"}],"financialInterests":"","formattedTitle":"Risk Factors of Tissue Expander Malposition in Two-Stage Breast Reconstruction","fulltext":[{"header":"Introduction","content":"\u003cp\u003eBreast reconstruction significantly improves patients' health-related quality of life, including satisfaction with appearance and enhanced physical, psychosocial, and sexual well-being following breast cancer surgery [\u003cspan additionalcitationids=\"CR2 CR3 CR4 CR5\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Alloplastic breast reconstruction, utilizing TEs and implants, is a prevalent method, accounting for over 65% of all breast reconstructions [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Tissue expander (TE) malposition is a clinically relevant complication in two-stage breast reconstruction, potentially leading to implant malposition, breast asymmetry, and reduced patient satisfaction. Both smooth- and textured-surface TEs can be affected, with smooth-surface TEs hypothesized to be more vulnerable due to their limited surface area and reduced tissue adherence. The reported incidence of malposition with smooth-surface TEs ranges from 2.9\u0026ndash;13.6% [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Malposition can result in skin expansion in unintended areas, leading to disfigurement of the reconstructed breast, the need for additional procedures, and increased financial burden. Limited data exist specifically addressing TE malposition as a complication.\u003c/p\u003e \u003cp\u003eThe purpose of this study was to investigate the incidence of TE malposition, identify associated risk factors, and discuss strategies to prevent and manage this complication.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eSubjects and Experimental Design\u003c/h2\u003e \u003cp\u003eThis retrospective cohort study included all consecutive patients undergoing breast operations between January 2020 and December 2021 at Mie University Hospital in Tsu, Japan. Inclusion criteria were: (1) age\u0026thinsp;\u0026ge;\u0026thinsp;18 years, (2) undergoing first-time post-mastectomy breast reconstruction using a TE as the initial stage, and (3) absence of surgical complications that would limit long-term follow-up. Exclusion criteria included severe neurological or psychiatric disorders affecting comprehension. All participants provided written informed consent. The study was approved by the local research ethics committee (Mie University IRBMED Number H2022-084) and was conducted in accordance with the Declaration of Helsinki.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eData Collection and Measurements\u003c/h3\u003e\n\u003cp\u003eDemographic and clinical data were collected prospectively, including: age, body mass index (BMI), follow-up duration, laterality, type of operation, cancer stage, history of radiotherapy or chemotherapy, breast surgery type, TE type, inframammary fold (IMF) plasty, tab suture, use of absorbable sutures, TE duration, first injection volume, and total injection volume. Ratios of first and total injection volume to BMI were also calculated. To minimize selection bias, two independent researchers reviewed and finalized the list of included studies, resolving any discrepancies through consensus.\u003c/p\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eStatistical Analysis\u003c/h2\u003e \u003cp\u003eData were analyzed using SPSS (ver. 29.0). Continuous variables with a normal distribution were presented as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation (SD), and categorical variables as number (percentage). The Chi-square test was used to compare categorical variables. Adjusted standardized residuals were calculated to identify cells with significantly higher or lower than expected frequencies. Variables with a significance level of P\u0026thinsp;\u0026lt;\u0026thinsp;0.05 were included in multivariate analysis. Risk factors associated with TE malposition were identified using linear stepwise regression analysis. A multiple linear regression model was constructed to explore risk factors for postoperative pain. Statistical significance was defined as a two-tailed P\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eStudy Participants\u003c/h2\u003e \u003cp\u003eThe study cohort comprised 32 subjects with a mean age of 49.0 ± 7.56 years, a mean BMI of 23.1 ± 4.0 kg/m2, and a mean follow-up period of 12.4 ± 5.0 months. Breast cancer laterality was equally distributed. The majority of cases were Stage I (43.8%) and Stage II (43.8%). A minority of patients (12.5%) received chemotherapy, and none received radiotherapy. Types of breast surgery included total mastectomy (59.4%), skin-sparing mastectomy (15.6%), and nipple-sparing mastectomy (21.9%). Sentinel lymph node biopsy was performed in 87.5% of cases, and axillary lymph node dissection in 9.4%. IMF plasty, tab suture, and use of absorbable sutures were performed in 6.3%, 65.6%, and 34.4% of cases, respectively. The mean TE duration was 10.1 ± 3.50 months. Mean first and total injection volumes were 142.2 ± 82.0 ml and 320.2 ± 117.5 ml, respectively. Mean first and total injection volume/BMI ratios were 6.2 ± 3.5 and 14.0 ± 4.9, respectively. Detailed participant demographics are shown in Table\u0026nbsp;1.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eComparison of malposition and non-malposition groups\u003c/h2\u003e \u003cp\u003eThree cases experienced TE malposition (Table\u0026nbsp;2). The mean age was significantly lower in the malposition group (39.7 ± 0.64 years) compared to the non-malposition group (49.9 ± 7.29 years; p \u0026lt; 0.001). NSM and Mx-15 occurred more frequently, and Bt and Mx-14 occurred less frequently in the malposition group compared to expected frequencies. IMF plasty was significantly more common in the malposition group (33.3% vs 3.4%; p = 0.04). The first injection volume was significantly higher in the malposition group (253.3 ± 128.6 ml) than in the non-malposition group (130.7 ± 69.3 ml; p = 0.01). First and total injection volume/BMI ratios were also significantly higher in the malposition group (11.0 ± 3.81 and 19.7 ± 3.75, respectively) compared to the non-malposition group (5.72 ± 3.11; p = 0.01 and 13.4 ± 4.69; p = 0.03, respectively). No other variables differed significantly between the groups.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eRisk Factors Associated with TE Malposition\u003c/h3\u003e\n\u003cp\u003eRegression analyses revealed that younger age (β -0.322, 95% confidence interval [CI] -0.025 to -0.001, p = 0.039) and larger TE size (β 0.469, 95% CI 0.043 to 0.201, p = 0.004) were significantly associated with a higher incidence of TE malposition (Table\u0026nbsp;3).\u003c/p\u003e\n\n"},{"header":"Cases","content":"\u003ch2\u003eCase 1\u003c/h2\u003e\u003cp\u003eA 39-year-old female patient (height: 162.5 cm, weight: 50.3 kg, BMI: 18.7) was diagnosed with invasive ductal carcinoma in the C region of the left breast, staged as T1cN0M0. The patient underwent left NSM, SNB, and TE insertion.\u003c/p\u003e\u003cp\u003eA smooth-type tissue expander (Natrelle® 133S MV-12-T, Allergan Plc, Madison, USA) was used. The TE tab was sutured and fixed using 3 − 0 VICRYL® (polyglactin 910, Ethicon Inc., Somerville, NJ, USA). The inframammary fold (IMF) was not reconstructed during the initial surgery. The initial saline fill volume was 160 ml. The patient did not receive adjuvant chemotherapy, radiotherapy, or hormonal therapy.\u003c/p\u003e\u003cp\u003eDuring monthly outpatient follow-up visits for saline injections, TE malposition was observed at 4 months post-surgery. At this point, the saline fill volume had reached 300 ml, and physical examination revealed inferior displacement of the left IMF by 3 cm compared to the contralateral side.\u003c/p\u003e\u003cp\u003eAt the patient’s request, breast reconstruction was performed using a profunda artery perforator (PAP) flap seven months after the initial surgery. This procedure successfully addressed the TE malposition.\u003c/p\u003e\u003cp\u003eNo additional corrective surgeries were required, and the patient has been followed up without complications (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\u003ch2\u003eCase 2\u003c/h2\u003e\u003cp\u003eA 39-year-old female patient (height: 164.6 cm, weight: 70.4 kg, BMI: 26.0) was diagnosed with non-invasive ductal carcinoma in the C region of the right breast, staged as TisN0M0. The patient underwent right SSM, SNB, and TE insertion.\u003c/p\u003e\u003cp\u003eA smooth-type tissue expander (Natrelle® 133S MV-14-T, Allergan Plc, Madison, USA) was used. The TE tab was sutured and fixed using 3 − 0 VICRYL® (polyglactin 910, Ethicon Inc., Somerville, NJ, USA). The IMF was created using Stratafix® Knotless Tissue Control Device (Ethicon Inc, Somerville, NJ, USA). The initial saline fill volume was 400 ml. The patient did not receive adjuvant chemotherapy, radiotherapy, or hormonal therapy.\u003c/p\u003e\u003cp\u003eDuring monthly outpatient follow-up visits, TE malposition was observed at 2 months post-surgery, when the saline fill volume had reached 520 ml.\u003c/p\u003e\u003cp\u003eAt the patient’s request, the TE was replaced with a silicone implant (Natrelle® JSSM-345) nine months after the initial surgery. This procedure successfully addressed the TE alposition.\u003c/p\u003e\u003cp\u003eNo additional corrective surgeries were required, and the patient has been followed up without complications (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis retrospective study identified several factors associated with TE malposition following breast reconstruction: younger age and larger TE size were significant risk factors. To our knowledge, limited research specifically addresses TE malposition. Fairchild et al. reported a 2.3% incidence of malposition with smooth-surface TEs [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. McLaughlin et al. found that smooth TEs had a 40-fold higher risk of malposition compared to textured TEs (13.6% vs 0.3%; P\u0026thinsp;\u0026lt;\u0026thinsp;0.001) [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Spear, et al. reported that the incidence rate of implant malposition of Natrelle\u0026reg; Round Silicone Breast Implants was 2.3% [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Studies on implant malposition have identified older age (OR 1.05, 95% CI 1.02\u0026ndash;1.07), BMI\u0026thinsp;\u0026lt;\u0026thinsp;25 (OR 1.64, 95% CI 1.00-2.70), and bilateral reconstruction (OR 13.41, 95% CI 8.50-21.16) as risk factors [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Our findings partially align with this, as younger patients with lower weight tended to experience TE malposition.\u003c/p\u003e \u003cp\u003eIn Japan, textured-surface TEs were historically favored due to a lower incidence of capsular contracture. However, following the recognition of breast implant-associated anaplastic large cell lymphoma (BIA-ALCL), textured TEs such as Natrelle\u0026reg; 133 (Allergan Plc, Madison, USA) were removed from Japanese insurance coverage [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Currently, smooth-surface TEs, such as the Natrelle\u0026reg; 133S (Allergan Plc, Madison, USA) are the standard for breast reconstruction. These TEs feature a 360-degree tab orientation for enhanced placement support [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Acellular dermal matrices are not approved for clinical use in Japan as of 2020 [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAs a measure of malposition management, a higher prosthesis volume-to-BMI ratio increases the risk of malposition. Within a specific volume range (20 \u0026times; BMI \u0026ndash; 300\u0026thinsp;\u0026plusmn;\u0026thinsp;100 mL), the incidence of malposition is significantly lower [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Additionally, multi-stabilizing surgical techniques\u0026mdash;such as firm tab fixation, strict pocket control, and careful selection of suture material\u0026mdash;are reported to reduce the risk of expander malposition and achieve favorable outcomes [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. Given the multifactorial nature of positional abnormalities, optimal results require accurate preoperative counseling and individualized surgical planning. Surgeons should comprehensively consider each patient\u0026rsquo;s profile (including age, body type, comorbidities, smoking history, and planned adjuvant therapy) and adjust surgical strategies accordingly (implant type, size, placement site, and fixation method). For example, in elderly patients or those with low BMI, artificial breasts tend to sag more easily due to insufficient soft tissue support to counteract gravity and pectoral muscle activity. Recognizing these complex interactions underscores the importance of a patient-centered, individualized approach, rather than focusing on a single cause. Surgeons must therefore select the optimal technique based on each patient\u0026rsquo;s unique risk factors. [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eIn cases where malposition was identified, reoperation was not always required, and favorable outcomes were achieved with two-stage reconstruction. Malposition can reduce patient satisfaction and may cause morphological abnormalities, such as unnatural appearance or asymmetry between the breasts. However, not all cases are clinically significant. For example, despite reports of 40-fold higher malposition rates with smooth-type TEs, there were cases where reoperation was unnecessary [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. The present case series also suggests that malposition can be observed even in cases with subclinical symptoms or only slight displacement. Distinguishing between minor and significant malposition is crucial to avoid unnecessary surgical intervention.\u003c/p\u003e \u003cp\u003eIn conclusion, preventing malposition requires meticulous surgical planning and technique, as well as individualized risk assessment and counseling. Ongoing evaluation of surgical outcomes and further studies are needed to establish standardized guidelines for the prevention and management of TE malposition.\u003c/p\u003e \u003cp\u003eThis study has several limitations. First, the relatively small sample size may restrict the statistical power and generalizability of the findings. Second, although we attempted to mitigate selection and search biases through independent review and consensus, these biases could not be fully excluded. Additionally, the homogeneity of the study population, resulting from the single-center design, may further limit the generalizability of our results. However, this single-center approach enabled the implementation of a standardized postoperative pain management protocol. To our knowledge, this study represents one of the first analyses of long-term postoperative malposition following breast surgery in Japanese patients.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAuthor contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Eisei Yoshizawa, Makoto Shiraishi and Ryohei Ishiura. The first draft of the manuscript was written by Eisei Yoshizawa and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003eAcknowledgements\u003c/p\u003e\n\u003cp\u003eCompliance with Ethical standards\u003c/p\u003e\n\u003cp\u003eData availability\u003c/p\u003e\n\u003cp\u003eData for this study are available upon request.\u003c/p\u003e\n\u003cp\u003eFunding\u003c/p\u003e\n\u003cp\u003eThe authors received no funding for data collection or preparation of the manuscript.\u003c/p\u003e\n\u003cp\u003eConflict of interest\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no conflict of interest.\u003c/p\u003e\n\u003cp\u003eEthical Approval \u003c/p\u003e\n\u003cp\u003eAll procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.\u003c/p\u003e\n\u003cp\u003eThis article does not contain any studies with animals performed by any of the authors.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eInformed consent\u003c/strong\u003e \u003c/p\u003e\n\u003cp\u003eInformed consent was obtained from all individual participants included in the study. Additional informed consent was obtained from all individual participants for whom identifying information is included in this article.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eMatros E, Albornoz CR, Razdan SN, Mehrara BJ, Macadam SA, Ro T, et al. Cost-effectiveness analysis of implants versus autologous perforator flaps using the BREAST-Q. Plast Reconstr Surg. 2015;135:937-946. doi:10.1097/PRS.0000000000001134.\u003c/li\u003e\n\u003cli\u003eHu ES, Pusic AL, Waljee JF, Kuhn L, Hawley ST, Wilkins E, et al. Patient-reported aesthetic satisfaction with breast reconstruction during the long-term survivorship Period. Plast Reconstr Surg. 2009;124:1-8. doi:10.1097/PRS.0b013e3181ab10b2.\u003c/li\u003e\n\u003cli\u003eDean C, Chetty U, Forrest AP. Effects of immediate breast reconstruction on psychosocial morbidity after mastectomy. Lancet 1983;1:459-62. doi:10.1016/s0140-6736(83)91452-6.\u003c/li\u003e\n\u003cli\u003eShiraishi M, Sowa Y, Inafuku N. Long-term survey of sexual well-being after breast reconstruction using the BREAST-Q in the Japanese population. Asian J Surg. 2022;46:150-155. doi:10.1016/j.asjsur.2022.02.007. \u003c/li\u003e\n\u003cli\u003eShiraishi M, Sowa Y, Tsuge I, Kodama T, Inafuku N, Morimoto N. Long-Term Patient Satisfaction and Quality of Life Following Breast Reconstruction Using the BREAST-Q: A Prospective Cohort Study. Front Oncol. 2022;12:815498. doi:10.3389/fonc.2022.815498.\u003c/li\u003e\n\u003cli\u003eShiraishi M, Sowa Y, Tomita K, Terao Y, Satake T, Muto M, et al. Performance of Artificial Intelligence Chatbots in Answering Clinical Questions on Japanese Practical Guidelines for Implant-based Breast Reconstruction. Aesthetic Plast Surg. 2025;49:1947-1953. doi:10.1007/s00266-024-04515-y.\u003c/li\u003e\n\u003cli\u003eCho MJ, Farhadi RV, Nash DW, Kaleeny J, Povoski SP, Chao AH. The current use of tissue expanders in breast reconstruction: device design, features, and technical considerations. Expert Rev Med Devices. 2024;21:27-35. doi: 10.1080/17434440.2023.2288911.\u003c/li\u003e\n\u003cli\u003eFairchild B, Ellsworth W, Selber JC, Bogue DP, Zavlin D, Nemir S, et al. Safety and Efficacy of Smooth Surface Tissue Expander Breast Reconstruction. Aesthet Surg J. 2020;40: 53-62. doi: 10.1093/asj/sjy199.\u003c/li\u003e\n\u003cli\u003eMcLaughlin C, Hughes AJ, Parham CS, Fritsche M, Potochny JD, Kunselman A, et al. Smooth Versus Textured Tissue Expander Breast Reconstruction: Complications and Efficacy. Ann Plast Surg. 2022;88:S288-S292. doi: 10.1097/SAP.0000000000003193.\u003c/li\u003e\n\u003cli\u003eSpear SL, Murphy DK; Allergan Silicone Breast Implant U.S. Core Clinical Study Group. Natrelle round silicone breast implants: Core Study results at 10 years. Plast Reconstr Surg. 2014;133:1354-1361. doi:10.1097/PRS.0000000000000021.\u003c/li\u003e\n\u003cli\u003eFracol M, Qiu CS, Chiu WK, Feld LN, Shah N, Kim JYS. Lateral and Inferior Implant Malposition in Prosthetic Breast Reconstruction: Incidence and Risk Factors. Plast Reconstr Surg Glob Open. 2020;8:e2752. doi:10.1097/GOX.0000000000002752.\u003c/li\u003e\n\u003cli\u003eIshii N. Current status of pre- or subpectoral breast reconstruction in Japan. Gland Surg. 2023;12:1786-1793. doi:10.21037/gs-23-221.\u003c/li\u003e\n\u003cli\u003eOkumura S, Hyodo I, Iwata H, Kamei Y. Immediate one-stage implant-based breast reconstruction without the use of acellular dermal matrix in Japanese breast cancer patients. Breast Cancer. 2020;27:759-764. doi:10.1007/s12282-020-01073-4.\u003c/li\u003e\n\u003cli\u003eScheflan M, Colwell AS. Tissue Reinforcement in Implant-based Breast Reconstruction. Plast Reconstr Surg Glob Open. 2014;2:e192. doi:10.1097/GOX.0000000000000140\u003c/li\u003e\n\u003cli\u003eNelson JA, Rubenstein RN, Vorstenbosch J, Haglich K, Poulton RT, McGriff D, et al. Textured versus Smooth Tissue Expanders: A Comparison of Complications in 3526 Breast Reconstructions. Plast Reconstr Surg. 2024;153:262e-272e. doi:10.1097/PRS.0000000000010600\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTables are available in the Supplementary Files section.\u003c/p\u003e\n"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Breast reconstruction, Tissue Expander, Breast Implant, Malposition","lastPublishedDoi":"10.21203/rs.3.rs-6814878/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6814878/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eTissue expander (TE) malposition is a notable complication in two-stage breast reconstruction, potentially leading to breast asymmetry and diminished patient satisfaction. Smooth-surface TEs are hypothesized to be more susceptible due to reduced tissue adherence. This study aimed to determine the incidence and risk factors associated with TE malposition and to discuss potential preventative strategies and corrective techniques.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003e A retrospective cohort study was conducted, reviewing data from 32 consecutive patients who underwent TE breast reconstruction at Mie University Hospital (Japan) between January 2020 and December 2021. The study collected demographic characteristics, surgical details, TE parameters, and injection volumes. Statistical analysis was performed using SPSS (ver. 29.0) to identify significant risk factors for TE malposition.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eThe overall incidence of TE malposition was 9.4% (3/32). Statistical analysis revealed that younger age (39.7\u0026thinsp;\u0026plusmn;\u0026thinsp;0.64 years vs. 49.9\u0026thinsp;\u0026plusmn;\u0026thinsp;7.29 years, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), the use of inframammary fold (IMF) plasty (33.3% vs 3.4%; p\u0026thinsp;=\u0026thinsp;0.04), larger TE size, and higher initial injection volume (253.3\u0026thinsp;\u0026plusmn;\u0026thinsp;128.6 ml vs. 130.7\u0026thinsp;\u0026plusmn;\u0026thinsp;69.3 ml, p\u0026thinsp;=\u0026thinsp;0.01) were significantly associated with TE malposition. Regression analyses identified younger age (p\u0026thinsp;=\u0026thinsp;0.039) and larger TE size (p\u0026thinsp;=\u0026thinsp;0.004) as independent predictors of TE malposition.\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e \u003cp\u003eYounger age, the application of IMF plasty, larger TE size, and higher first injection volume are significant risk factors for TE malposition in two-stage breast reconstruction. These findings may inform surgical decision-making and postoperative care, potentially reducing the incidence of TE malposition.\u003c/p\u003e","manuscriptTitle":"Risk Factors of Tissue Expander Malposition in Two-Stage Breast Reconstruction","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-06-11 06:08:36","doi":"10.21203/rs.3.rs-6814878/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"471df03f-58c6-4746-99c6-b3ec84d4bc3e","owner":[],"postedDate":"June 11th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-07-02T07:33:02+00:00","versionOfRecord":[],"versionCreatedAt":"2025-06-11 06:08:36","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6814878","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6814878","identity":"rs-6814878","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}