External Screw-Threaded Traction Device Helps Optimize Finger Joint Mobility in Severe Stage III and IV Dupuytren Disease.

BACKGROUND Treating advanced finger joint contractures from Dupuytren disease remains a challenge. We evaluated the effectiveness of a skeletal distraction device versus alternative treatment options. MATERIAL AND METHODS We analyzed the surgical treatment of contracted finger joints in stage III and stage IV Dupuytren's disease over a 10-year period. Data were obtained from inpatient and outpatient medical records, including postoperative clinical examinations and extended Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire scores. Complications of infection, postoperative pain, and wound healing disorders were recorded. RESULTS A total of 79 patients (83 hands) were assigned to 2 treatment groups. Patients in group 1 underwent an initial open transection of the main fibrous cord, Z-plasty, distraction with the Erlangen external distraction device, and fasciectomy. The distraction period was 13 to 81 days (mean 31 days). Group 2 underwent a conventional single-stage fasciectomy and arthrolysis. DASH scores and subjective patient satisfaction were lower in group 1 (20.7/33%) than in group 2 (10.3/50%). However, the staged approach of group 1 to treat proximal interphalangeal joint contractures in the long term (improvement >40%) was more effective than the approach of group 2 (>33%). Distraction device pin infections occurred in 20% of hands. Postoperative pain and complex regional pain syndrome type I occurred in 25% of hands in group 1 and 3% in group 2. CONCLUSIONS A screw thread driven external fixation device is useful in end-stage Dupuytren's finger joint contractures. It is indicated when joint contractures are advanced and simple arthrolysis is insufficient.

Retrospective analysis of free temporoparietal fascial flap for defect reconstruction of the hand and the distal upper extremity.

INTRODUCTION: Soft tissue reconstruction of the hand and distal upper extremity is challenging to preserve the function of the hand as good as possible. Therefore, a thin flap has been shown to be useful. In this retrospective study, we aimed to show the use of the free temporoparietal fascial flap in soft tissue reconstruction of the hand and distal upper extremity. METHODS: We analysed the outcome of free temporoparietal fascial flaps that were used between the years 2007and 2016 at our institution. Major and minor complications, defect location and donor site morbidity were the main fields of interest. RESULTS: 14 patients received a free temporoparietal fascial flap for soft tissue reconstruction of the distal upper extremity. Minor complications were noted in three patients and major complications in two patients. Total flap necrosis occurred in one patient. CONCLUSION: The free temporoparietal fascial flap is a useful tool in reconstructive surgery of the hand and the distal upper extremity with a low donor site morbidity and moderate rates of major and minor complications.

Aspergillus fumigatus Spores Are Not Able to Penetrate Silicone Breast Implant Shells.

INTRODUCTION: Bacterial contamination is hypothesized to be one reason for the development of capsular contracture after alloplastic breast reconstruction using silicone breast implants. The role of fungal colonization or infection in this context as well as the question if microorganisms can penetrate the shell of silicone breast implants remains an unresolved question to date. Therefore, the aim of this study was to assess whether fungal spores are able to penetrate the shell of silicone implants. MATERIALS AND METHODS: In an experimental in vitro setup with different arrangements of growth compartments, silicone chambers were placed in culture dishes filled with Aspergillus minimal medium or liquid culture medium. Inoculation was performed with conidia of Aspergillus fumigatus and incubated for seven days. On a daily basis, plates were inspected for conidial germination and hyphal growth. RESULTS: In none of the different experimental settings nutrients or hyphae of Aspergillus fumigatus were able to penetrate the silicone material. CONCLUSIONS: Fungal spores and hyphae do not permeate through an intact silicone shell used in breast implants; thus, the silicone material serves as an impenetrable barrier.

Keratinocyte Monolayers on Hyaluronic Acid Membranes as "Upside-Down" Grafts Reconstitute Full-Thickness Wounds.

BACKGROUND Skin replacement by means of cultured epithelial keratinocytes is a well-accepted method. However, several clinical drawbacks of sheet autografts (CEA - cultured epithelial autografts) have stimulated various efforts to optimize cell culture and cell delivery. Recent developments include use of cell monolayers instead of a fully differentiated epithelium, as well as use of various biomaterials to grow and transport the cultured cells. To optimize the transfer of human keratinocytes directly to the recipient wound bed, we used an "upside-down" technique, delivering cultured cells directly to the wound with the carrier material on top. MATERIAL AND METHODS Subconfluent second-passage human keratinocyte monolayers on esterified hyaluronic acid membranes (KHAMC - Keratinocyte-Hyaluronic-Acid-Membrane-Composites) were transplanted either as upside-down grafts or as upside-up grafts onto standardized full-thickness wounds in athymic nude mice versus controls with the cell-free membrane alone. RESULTS In the upside-down group, 14 days after grafting, a multi-layered, differentiating epidermis was found, whereas the wounds in the upside-up group and in the control group were not completely closed up to day 21. Persistence of human keratinocytes was shown in the upside-down group only, from day 7 until day 35 after grafting. CONCLUSIONS This study confirms that upside-down grafting of subconfluent monolayers of serum-free cultured human keratinocytes on esterified hyaluronic acid membranes is a suitable means to transfer actively proliferative keratinocytes, and reduces wound contraction. Compared to standard grafting protocols of cultured epithelium, such as CEA sheet grafts, it is easier to apply, does not need enzymatic detachment of cells from the culture dish, and limits the number of production steps required.

Can systemically administered antibiotics be detected in wound tissues and surfaces under negative pressure wound therapy?

In this study, we evaluated a new aspect of negative pressure wound therapy (NPWT) as an analytical tool for pharmacokinetic studies. Twenty-one patients with soft tissue defects scheduled to receive NPWT were included in this study. Concomitant to NPWT, all patients received intravenous moxifloxacin (MX). At different time intervals, blood plasma levels of MX were sampled and compared with synchronous concentrations of MX in the exudate obtained from the NPWT drainage system. Serial measurements were performed upon initiation of the therapy as well as in the steady state (after 5 days). At steady state, wound tissue was obtained intraoperatively. High-performance liquid-chromatography (HPLC) was used for analysis. At 1 hour post-administration, the exudate/plasma levels (mg/L) were 1.92/3.07; at 12 hours, 0.80/1.14; at 24 hours, 0.26/0.43; and at 120 hours (steady state), 0.42/0.47. There was a correlation between exudate and plasma levels reaching approximately 0.75. Until now, methods for pharmacokinetic studies concerning interstitial fluid are difficult to apply in the clinical context. The presented method showed limitations, but we believe that, after methodological improvements, measurements of substances in the interstitial fluid by means of NPWT are feasible.

Reconstruction of composite defects of the scalp and neurocranium-a treatment algorithm from local flaps to combined AV loop free flap reconstruction.

BACKGROUND: Reconstruction of cranial composite defects, including all layers of the scalp and the neurocranium, poses an interdisciplinary challenge. Especially after multiple previous operations and/or radiation therapy, sufficient reconstruction is often only possible using microsurgical free flap transplantation. The aim of this study was to analyze the therapy of interdisciplinary cases with composite defects including the scalp and neurocranium. METHODS: From 2009 to 2017, 23 patients with 18 free flaps and 10 pedicled/local flaps were analyzed. First choices for free flaps were muscle flaps followed by fasciocutaneous flaps. RESULTS: Except for four patients, a stable coverage could be reached in the first operation. Three of these patients received a local scalp rotation flap in the first operation and needed an additional free flap because the local flap was no longer sufficient for coverage after wound healing deficiency or tumor relapse. The superficial temporal artery or external carotid artery served as recipient vessels. In special cases, venous grafts or an arteriovenous loop (AV loop) were used as extensions for the recipient vessels. CONCLUSIONS: In summary, an interdisciplinary approach with radical debridement of infected or necrotic tissue and the reconstruction of the dura mater are essential to reach a stable, long-lasting reconstructive result. Based on our experience, free flaps seem to be the first choice for patients after multiple previous operations and/or radiation therapy.

Negative pressure wound treatment with computer-controlled irrigation/instillation decreases bacterial load in contaminated wounds and facilitates wound closure.

Microbial wound contamination is known to be a hindrance to wound healing. Negative pressure wound therapy (NPWT) with or without irrigation is known to optimise conditions in problem wounds. The aim of this study was to investigate the influence of computer-controlled wound irrigation with NPWT on the bacterial load in contaminated wounds. A total of 267 patients were treated with NPWT with automated instillation because of problematic wounds using an antiseptic instillation solution. In 111 patients, a minimum of 4 operative procedures were necessary, and swabs were taken at least at the first and at the fourth operation in a standardised procedure. The number of different bacteria and the amount of bacteria were analysed during the course. In a subgroup of 51 patients, swabs were taken at all 4 operative procedures and analysed separately. In an overall analysis, the number of different bacteria and the amount of bacteria significantly decreased independent of wound localisation and diagnosis. NPWT with automated instillation demonstrates a positive influence in the reduction of bacterial load in problem wounds. Thus, it may help to optimise wound conditions before definite wound closure.

Combined free flaps with arteriovenous loops for reconstruction of extensive thoracic defects after sternal osteomyelitis.

BACKGROUND: Various local flaps have been described for patients suffering from sternal osteomyelitis and are regarded as a standard procedure for defect reconstruction. In contrast, the use of microsurgical free flaps has been reported anecdotally only. We present our experiences with the combination of an arteriovenous loop and a free flap transfer in defects larger than half of the sternum. METHODS: Between January 2012 and October 2014, eight patients with a mean age of 68 years who suffered from extensive deep sternal osteomyelitis were operated in a consecutive series. After radical surgical debridement, the defect size comprised all three thirds of the sternum. Defect reconstruction was achieved by means of free flap transplantation using the vastus lateralis myocutaneous flap, rectus abdominis, and bipedicled latissimus dorsi/parascapular flap. As local recipient vessels were depleted in all patients, the pedicle of the flap was anastomosed to a high-flow and short-length subclavian arteriovenous loop as recipient vessel in all cases. RESULTS: The immediate postoperative course in all patients was uneventful despite one axonal injury to the femoral nerve at the donor site. There was no partial or total flap loss. During a mean follow-up of 9 months, one patient suffered from a local infection at the donor site. In all patients, a successful defect reconstruction could be achieved. CONCLUSION: Depletion of local recipient vessels as an obstacle for free flap reconstruction can be overcome by creating an arteriovenous loop. Even extensive defects are adequate for defect reconstruction using a single or, in extreme cases, bipedicled free flap.

Penile reconstruction with dermal template and vacuum therapy in severe skin and soft tissue defects caused by Fournier's gangrene and hidradenitis suppurativa.

The aim of this article is to improve the treatment of patients with complete skin loss of the penile shaft after Fournier's gangrene or hidradenitis suppurativa using modern biomatrices and topical negative pressure therapy. From January 2010 to December 2011, three patients with Fournier's gangrene or hidradenitis suppurativa were treated. After initial radical debridements, topical negative pressure therapy was applied for wound stabilisation. After that dermal templates (acellular dermal matrix) were used to achieve early healing and topical negative pressure-dressing in a special setting or a special foam compression bandage was used together with a urinary catheter. After integration of the dermal template, a split-thickness skin graft is used for coverage and again secured with a circular total negative pressure-dressing. In all cases, the split-thickness skin grafts healed very well applying this therapy concept. The patients were very satisfied with the functional as well as with the aesthetic outcome. We suggest a new method of staged reconstruction to successfully preserve the functionality of the penis after complete loss of the skin and soft tissue of the penile shaft using modern biomatrices and topical negative pressure therapy.

Is there a Rationale for Autologous Breast Reconstruction in Older Patients? A Retrospective Single Center Analysis of Quality of life, Complications and Comorbidities after DIEP or ms-TRAM Flap Using the BREAST-Q.

Autologous breast reconstruction with the deep inferior epigastric perforator (DIEP) or muscle-sparing transverse rectus abdominis myocutaneous (ms-TRAM) flap is a common method in the majority of patients after mastectomy. Because of an increased perioperative risk profile the benefit in older patients is questionable. To assess the postoperative quality of life and peri- and post-operative complications of older compared to younger patients is the aim of this retrospective study. In a retrospective analysis 39 older (i.e. >60 years) and 140 younger patients (i.e. <60 years) with autologous breast reconstruction in the Department of Plastic Surgery at the University Hospital of Erlangen-Nuernberg were surveyed at least 6 month postoperative using the BREAST-Q questionnaire. Correlations were generated between comorbidities and complications. Significant differences were observed regarding hospitalization, pre-existing diseases and the choice of DIEP versus ms-TRAM flaps. Parameters such as major and minor complications, bulging or hernia and risk factors (e.g. smoking or obesity) showed no significant differences. The results of the questionnaire parameters showed no significant difference between both groups, revealing high satisfaction with the aesthetic result and an improvement in quality of life independent of age. Autologous breast reconstruction after mastectomy generates a gain in quality of life and shows a good to excellent overall satisfaction in older as well as younger patients. Despite a longer hospitalization and a different risk profile there were no significant differences regarding minor and major complications in the postoperative course. Hence autologous breast reconstruction for older patients is justified and should be taken into consideration.

Vessel transformation in chronic wounds under topical negative pressure therapy: an immunohistochemical analysis.

The underlying physiological mechanism of topical negative pressure (TNP) therapy is not yet completely understood. This prospective clinical study aims to clarify a potential influence of TNP therapy on vessel proliferation and hypoxia in chronic wounds. TNP was applied on chronic wounds of 16 patients (-125 mmHg) to prepare them for a plastic-surgical reconstruction using free or pedicled flaps. Tissue biopsies were taken from the wound edge and wound bed at different time points. All samples were stained with haematoxylin and eosin, hypoxia-induced factor-1α and endothelial cell markers (CD31 and CD34) for the immunohistological analysis of inflammation, hypoxia and vessel proliferation. Between day 5 and day 8 of treatment, a considerable increase in blood vessel density could be observed, reaching a maximum of approximately 200% in contrast to the vessel density prior to treatment. In addition, the number of hypoxic and inflammatory cells was found to be increased at particular time points. This study demonstrates a stimulating effect on vessel proliferation under TNP treatment. TNP appears to support (neo-) angiogenesis and transformation of chronic non-healing wounds in a physiological wound healing process when combined with surgical debridement. This effect underlines the positive influence of TNP in the treatment of chronic wounds as shown by various clinical reports.

PHDs inhibitor DMOG promotes the vascularization process in the AV loop by HIF-1a up-regulation and the preliminary discussion on its kinetics in rat.

BACKGROUND: The Arterovenous Loop (AV Loop) model is a vascularization model in tissue engineering research, which is capable of generating a three dimensional in vivo unit with cells as well as the supporting vessels within an isolation chmaber. In our previous studies the AV loop in the isolation chamber was discovered to undergo hypoxia, characterized by Hypoxia Inducible Factor (HIF) up-regulation. The vascularization followed the increase of HIF-α temporally, while it was spatially positively correlated with the HIF-α level, as well. This study aims to prove that HIF-1a up-regulation is the stimulus for vascularization in the AV loop model. METHOD: The AV loop model in rats was created by interposing a femoral vein graft into the distal ends of the contralateral femoral artery and vein, and the loop was embeded in fibrin matrix and fixed in isolation chamber. PHD (prolyl hydroxylases) inhibitor DMOG (Dimethyloxallyl Glycine) was applied systemically in the rats in 40 mg/KG at day 0 and day 3 (DMOG-1), or in 15 mg/KG at day 8, day10 and day12 (DMOG-2). Two weeks later the specimens were explanted and underwent morphological and molecular evaluations. RESULTS: Compared to the control group, in the DMOG-2 group the HIF-1α positive rate was siginicantly raised as shown in immunohistochemistry staining, accompanied with a smaller cross section area and greater vessel density, and a HIF-1α accumulation in the kidney. The mRNA of HIF-1α and its angiogenic target gene all increased in different extends. Ki67 IHC demostrate more positive cells. There were no significant change in the DMOG-1 group. CONCLUSION: By applying DMOG systemically, HIF-1α was up-regulated at the protein level and at the mRNA level, acompanied with angiogenic target gene up-regulateion, and the vascularization was promoted correspondingly. DMOG given at lower dosage constantly after one week tends to have better effect than the group given at larger dosage in the early stage in this model, and promotes cell proliferation, as evidenced by Ki67 IHC. Thus, this study proves that HIF-1a up-regulation is the stimulus for vascularization in the AV loop model and that the process of the vessel outgrowth can be controlled in the AV Loop model utilizing this mechanism.

Salvage of a free radial forearm flap by creation of an arteriovenous fistula at the distal arterial pedicle.

Interdisciplinary approaches with infrainguinal bypass grafts and free flaps between the plastic and vascular surgery may well offer an opportunity for diabetic patients with peripheral vascular disease to salvage their critically affected limbs. A free flap transfer combined with an autologous vein graft can cover large tissue defects and simultaneously improve distal perfusion even in patients with arterial occlusive disease. We are presenting a case of bypass-free radial forearm flap used to cover a foot defect in an old diabetic patient with peripheral arterial disease. The flap perfusion deteriorated significantly during the early postoperative period. The patient was brought back to the operating room with acute thrombosis of the popliteal-radial venous graft and the arterial pedicle of the flap. The flap was salvaged by thrombectomy and creation of an additional arteriovenous fistula at the distal arterial pedicle. The procedure improved the flap perfusion and decreased the high internal resistance that was noticed in the flap when trying to flush the radial artery during the revision surgery and was evident by continuous wave -Doppler sonography. The successful salvage of the flap in the presented case and the convenient long-term follow up suggest that this technique may be safe and helpful as a last effort to salvage a bypass-free flap with a suspected high internal resistance.

Interdisciplinary Treatment of Breast Cancer After Mastectomy With Autologous Breast Reconstruction Using Abdominal Free Flaps in a University Teaching Hospital-A Standardized and Safe Procedure.

Background: Breast cancer is the most common malignancy in women. The interdisciplinary treatment is based on the histological tumor type, the TNM classification, and the patient's wishes. Following tumor resection and (neo-) adjuvant therapy strategies, breast reconstruction represents the final step in the individual interdisciplinary treatment plan. Although manifold flaps have been described, abdominal free flaps, such as the deep inferior epigastric artery perforator (DIEP) or the muscle-sparing transverse rectus abdominis myocutaneous (ms-TRAM) flap, are the current gold standard for autologous breast reconstruction. This retrospective study focuses on the safety of autologous breast reconstruction upon mastectomy using abdominal free flaps. Methods: From April 2012 until December 2018, 193 women received 217 abdominal free flaps for autologous breast reconstruction at the University Hospital of Erlangen. For perforator mapping, we performed computed tomography angiography (CTA). Venous anastomosis was standardized using a ring pin coupler system, and flap perfusion was assessed with fluorescence angiography. A retrospective analysis was performed based on medical records, the surgery report, and follow-up of outpatient course. Results: In most cases, autologous breast reconstruction was performed as a secondary reconstructive procedure after mastectomy and radiotherapy. In total, 132 ms1-TRAM, 23 ms2-TRAM, and 62 DIEP flaps were performed with 21 major complications (10%) during hospital stay including five free flap losses (2.3%). In all cases of free flap loss, we found an arterial thrombosis as the main cause. In 24 patients a bilateral breast reconstruction was performed without free flap loss. The majority of free flaps (96.7%) did not need additional supercharging or turbocharging to improve venous outflow. Median venous coupler size was 2.5 mm (range, 1.5-3.5 mm). Conclusion: Using CTA, intraoperative fluorescence angiography, titanized hernia meshes for rectus sheath reconstruction, and venous coupler systems, autologous breast reconstruction with DIEP or ms-TRAM free flaps is a safe and standardized procedure in high-volume microsurgery centers.

Body Contouring Surgery Improves Physical Activity in Patients After Massive Weight Loss-a Retrospective Study.

BACKGROUND: The aim of the study was to compare physical activity (PA) in patients who had undergone massive weight loss (MWL), before and after body contouring procedures. METHODS: All patients undergoing body contouring surgery after MWL between 2007 and 2017 with a minimum follow-up of 6 months after the last procedure were included in this retrospective study. Excluded were those with a body mass index > 35 kg/m2 and those with comorbidities leading to impaired PA. Quality of life (QOL) was assessed using the Moorehead-Ardelt QOL Questionnaire II. Evaluation of PA was obtained with the International Physical Activity Questionnaire (IPAQ) short form and the Freiburg PA Questionnaire. Functional impairment during exercise was analyzed using a self-designed functional impairment score (FIS). RESULTS: In the 45 patients completing the survey (37 female, 8 male), an improvement in QOL (p < 0.001) and PA scored by the IPAQ (p = 0.017) was found. The Freiburg PA Questionnaire showed no difference in PA before and after body contouring surgery (p = 0,274). Furthermore, scores of the FIS indicated a decrease of functional impairment during physical activity after body contouring surgery (p < 0.001). CONCLUSION: Body contouring improves QOL and PA in patients after massive weight loss. The results of our study confirm the important role of plastic surgery in the treatment and maintenance of health of patients with former obesity.

Enhancing Safety in Reconstructive Microsurgery Using Intraoperative Indocyanine Green Angiography.

Intraoperative assessing and postoperative monitoring of the viability of free flaps is of high relevance in reconstructive microsurgery. Today different methods for the evaluation of tissue perfusion are known. Indocyanine Green angiography is an emerging technique among plastic surgeons with a broad scope of applications especially in microsurgical free flap transfer. We demonstrate the value and clinical application of this technique based on representative selected cases where Indocyanine Green angiography was used in microsurgical free flap transfers from different anatomic donor sites during the operation. Hereby perforator selection, flap tailoring, changes of blood flow and patency of anastomoses was judged and decision making was based on the angiographic findings. This method has proven to be valid, reproducible and easy to use. The application is not limited to the evaluation of skin perfusion, but is also applicable to muscle tissue or chimeric or composite flaps. Reliable judgement is especially given for the extent of arterially perfused tissue following complete flap dissection. Moreover, this real-time angiography revealed a high sensitivity for the detection of poorly perfused flap areas, thus supporting the conventional clinical judgement and reducing complications. In summary Indocyanine Green angiography has the potential to reduce flap related complications and to contribute to enhancing and extending the possibilities of free flap surgery.

Operating on the Edge? Body Contouring Procedures in Patients with Body Mass Index Greater 35.

BACKGROUND: Body contouring surgery after massive weight loss was shown to ameliorate the patient's quality of life and to enhance physical and psychological well-being. However, numerous patients are still obese when presenting for body contouring surgery, not able to lose additional weight for various reasons. Data regarding general feasibility, outcome, and postoperative complications in obese patients is rare. The aim of this study was to investigate the outcome in body contouring procedures in obese patients. METHODS: A retrospective chart review of 65 cases in 42 patients was performed. Patients with a body mass index (BMI) > 35 kg/m2 at the time of operation were enrolled and all different types of body contouring surgery were included. Complications were classified as major (need for surgical intervention) and minor complications. RESULTS: The median BMI of all patients was 38 kg/m2 (range 35.1-65.1 kg/m2). The majority of performed types of body contouring was abdominal body contouring (panniculectomy n = 27 (42%), abdominoplasty n = 12 (18%)). Complications occurred in 27 cases (41.5%). Twenty-one cases (32.3%) were classified as minor complications, six (9.2%) as major complications. The most common major complications were hematoma and wound dehiscence; the most common minor complication was seroma. CONCLUSION: A reasonable risk for complications is well known in body contouring surgery especially in obese patients. It is imperative to discuss related risks and expected results. Taking several points into account concerning the perioperative management, reduction of major complications is possible even in still obese patients, making body contouring surgery a discussible option.

Is short term intraoperative application of disinfectants harmful to breast implants in breast reconstruction? An experimental study and literature survey.

OBJECTIVES: Bacterial contamination of breast implants and biofilm formation has been discussed as a major reason for implant loss and capsular contraction. Intra- and perioperative treatment of breast implants with disinfectants to prevent bacterial contamination has been frequently reported. Given the increasing awareness of concerns about product liability the question of whether short-time irrigation of implants with antimicrobial substances during the operative procedure would potentially alter the integrity of the implant shell has attracted legal and medical interest. In this study we therefore investigated whether irrigating breast implants with antimicrobials commonly used in clinical practice with a clinically relevant application time would affect the physical integrity of the implant shell. MATERIALS AND METHODS: Samples, which were previously punched from the shell of explanted standard silicone gel filled breast implants in a defined way, were exposed to different disinfectant solutions for two minutes. Multiple defined specimens from 5 different explants from 4 different producers (including PIP) were tested. The testing included tensile strength and disruption tests. RESULTS: In our prospective test series we could not find a significant influence of a single distinct disinfectant on silicone shell implant surfaces. CONCLUSION: Despite the potential legal implications that might be considered when a surgeon manipulates an implant with disinfectants intraoperatively, we find it worthwhile to state that from a material and surgical standpoint there is no evidence that short-time treatment of alloplastic materials would be detrimental to the physical properties of the implant shell.