Long-term in vivo survival of 3D-bioprinted human lipoaspirate-derived adipose tissue: proteomic signature and cellular content.

Three-dimensional (3D)-bioprinted lipoaspirate-derived adipose tissue (LAT) is a potential alternative to lipo-injection for correcting soft-tissue defects. This study investigated the long-term in vivo survival of 3D-bioprinted LAT and its proteomic signature and cellular composition. We performed proteomic and multicolour flow cytometric analyses on the lipoaspirate and 3D-bioprinted LAT constructs were transplanted into nude mice, followed by explantation after up to 150 days. LAT contained adipose-tissue-derived stem cells (ASCs), pericytes, endothelial progenitor cells (EPCs) and endothelial cells. Proteomic analysis identified 6,067 proteins, including pericyte markers, adipokines, ASC secretome proteins, proangiogenic proteins and proteins involved in adipocyte differentiation and developmental morphogenic signalling, as well as proteins not previously described in human subcutaneous fat. 3D-bioprinted LAT survived for 150 days in vivo with preservation of the construct shape and size. Furthermore, we identified human blood vessels after 30 and 150 days in vivo, indicating angiogenesis from capillaries. These results showed that LAT has a favourable proteomic signature, contains ASCs, EPCs and blood vessels that survive 3D bioprinting and can potentially facilitate angiogenesis and successful autologous fat grafting in soft-tissue reconstruction.

Vascularization of tissue engineered cartilage - Sequential in vivo MRI display functional blood circulation.

Establishing functional circulation in bioengineered tissue after implantation is vital for the delivery of oxygen and nutrients to the cells. Native cartilage is avascular and thrives on diffusion, which in turn depends on proximity to circulation. Here, we investigate whether a gridded three-dimensional (3D) bioprinted construct would allow ingrowth of blood vessels and thus prove a functional concept for vascularization of bioengineered tissue. Twenty 10 × 10 × 3-mm 3Dbioprinted nanocellulose constructs containing human nasal chondrocytes or cell-free controls were subcutaneously implanted in 20 nude mice. Over the next 3 months, the mice were sequentially imaged with a 7 T small-animal MRI system, and the diffusion and perfusion parameters were analyzed. The chondrocytes survived and proliferated, and the shape of the constructs was well preserved. The diffusion coefficient was high and well preserved over time. The perfusion and diffusion patterns shown by MRI suggested that blood vessels develop over time in the 3D bioprinted constructs; the vessels were confirmed by histology and immunohistochemistry. We conclude that 3D bioprinted tissue with a gridded structure allows ingrowth of blood vessels and has the potential to be vascularized from the host. This is an essential step to take bioengineered tissue from the bench to clinical practice.

Long-term in vivo integrity and safety of 3D-bioprinted cartilaginous constructs.

Long-term stability and biological safety are crucial for translation of 3D-bioprinting technology into clinical applications. Here, we addressed the long-term safety and stability issues associated with 3D-bioprinted constructs comprising a cellulose scaffold and human cells (chondrocytes and stem cells) over a period of 10 months in nude mice. Our findings showed that increasing unconfined compression strength over time significantly improved the mechanical stability of the cell-containing constructs relative to cell-free scaffolds. Additionally, the cell-free constructs exhibited a mean compressive stress and stiffness (compressive modulus) of 0.04 ± 0.05 MPa and 0.14 ± 0.18 MPa, respectively, whereas these values for the cell-containing constructs were 0.11 ± 0.08 MPa (p = .019) and 0.53 ± 0.59 MPa (p = .012), respectively. Moreover, histomorphologic analysis revealed that cartilage formed from the cell-containing constructs harbored an abundance of proliferating chondrocytes in clusters, and after 10 months, resembled native cartilage. Furthermore, extension of the experiment over the complete lifecycle of the animal model revealed no signs of ossification, fibrosis, necrosis, or implant-related tumor development in the 3D-bioprinted constructs. These findings confirm the in vivo biological safety and mechanical stability of 3D-bioprinted cartilaginous tissues and support their potential translation into clinical applications.

The Aesthetically Ideal Position of the Nipple-Areola Complex on the Breast.

BACKGROUND: Several studies have attempted to identify an objective description of the aesthetically ideal breast, but they have all suffered in their reliability because of having several intrinsic limitations. It is therefore essential to design a template of ideal breast features in order to predict and evaluate aesthetic outcomes in both reconstructive and cosmetic breast surgery. The aim of this study was to determine the aesthetically preferred position of the nipple- areola complex on the breast. METHODS: A questionnaire was sent by regular mail to 1000 men and 1000 women aged between 16 and 74 years. They were asked to rank the attractiveness of a series of breasts of women in images with different NAC positions. The images showed breasts from two different angles: 12 frontal-view images with both breasts shown, and five sideview images with only one breast shown. All of the breasts had equal dimensions and proportions, with the same areola size but different NAC positions. Statistical analysis of data was carried out. RESULTS: Eight hundred and thirteen of 2000 participants completed the questionnaire. The NAC placement preferred by both genders had a ratio of 40:60 x and 50:50 y, which means that it was best situated in the middle of the breast gland vertically and slightly lateral to the midpoint horizontally. Significant differences were found between the age and gender subgroup preferences. CONCLUSIONS: This study identified the preferred position of the nipple-areola complex on the female breast in the general population. This is an important information when planning breast reconstructive and cosmetic surgery. LEVEL OF EVIDENCE II: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

The effect of hemodilution on free flap survival: A systematic review of clinical and experimental studies.

BACKGROUND: Acute normovolemic hemodilution (ANH) has been proposed as a microsurgical technique to improve blood flow in free flaps. OBJECTIVE: Here, we present the first systematic review of clinical and experimental studies on the effect of ANH. METHODS: We performed a systematic literature search of PubMed, Medline, the Cochrane Library, Google Scholar, and ClinicalTrials.gov using search strategies and a review process in agreement with the PRISMA statement and the Cochrane Handbook for systematic reviews of interventions. PICO criteria were defined before bibliometric processing of the retrieved articles, which were analyzed with the SYRCLE RoB tool for risk of bias and the GRADE scale for level of evidence. RESULTS: We retrieved 74 articles from the literature search, and after processing according to PICO criteria, only four articles remained, all of which were experimental. The rating for risk of bias was uncertain according to SYRCLE RoB results, and the level of evidence was low according to GRADE evaluation. CONCLUSIONS: There is no clinical evidence for the effect of ANH on microcirculation in free flaps, and experimental studies provide weak evidence supporting the use of hemodilution in reconstructive microsurgery.

Does ischemic preconditioning increase flap survival by ADORA2B receptor activation?

BACKGROUND: Ischemic preconditioning (IPC) is defined as raising tolerance to subsequent ischemic stress by exposing tissues to sub-lethal ischemia. Although many candidates have been suggested, recent studies have clearly demonstrated that adenosine-mediated ADORA2B receptor (ADORA2BR) activation is the main mechanism involved in IPC. While the tissue-protective role of this mechanism has been demonstrated in different ischemia/reperfusion (I/R) models, its role in flap surgery-derived I/R damage has not to date been investigated. OBJECTIVE: To investigate the role of adenosine and ADORA2BR activation in IPC-mediated tissue protection in an epigastric flap model. METHODS: Animals were divided into five main groups, all of which were then divided into two subgroups depending on whether or not they were exposed to IPC before the I/R procedure, which consisted of 6 hours of ischemia and 6 days of reperfusion. No drugs were administered in Group 1 (the control group). Animals in Group 2 were pretreated with CD73-inhibitor before IPC application or the ischemic period. Animals in Group 3 were pretreated with adenosine. Animals in Group 4 were pretreated with an ADORA2BR antagonist, and those in Group 5 with an ADORA2BR agonist. After 6 days of reperfusion, tissue survival was evaluated via histological and macroscopic analysis. RESULTS: IPC application significantly enhanced CD73 expressions and adenosine concentrations (p < 0.01). Flap survivals were increased by IPC in Group 1 (p < 0.05). However, CD73 inhibition blocked this increase (Group 2). In Group 3, adenosine improved flap survival even in the absence of IPC (p < 0.01). While an ADORA2BR antagonist attenuated the tissue-protective effect of IPC (p < 0.01), the ADORA2BR agonist improved flap survival by mimicking IPC in groups 4 and 5. CONCLUSION: These results provide pharmacological evidence for a contribution of CD73 enzyme-dependent adenosine generation and signaling through ADORA2BR to IPC-mediated tissue protection. They also suggest for the first time that ADORA2BR agonists may be used as a potential preventive therapy against I/R injury in flap surgeries.

In Vivo Human Cartilage Formation in Three-Dimensional Bioprinted Constructs with a Novel Bacterial Nanocellulose Bioink.

Bacterial nanocellulose (BNC) is a 3D network of nanofibrils exhibiting excellent biocompatibility. Here, we present the aqueous counter collision (ACC) method of BNC disassembly to create bioink with suitable properties for cartilage-specific 3D-bioprinting. BNC was disentangled by ACC, and fibril characteristics were analyzed. Bioink printing fidelity and shear-thinning properties were evaluated. Cell-laden bioprinted grid constructs (5 × 5 × 1 mm3) containing human nasal chondrocytes (10 M mL-1) were implanted in nude mice and explanted after 30 and 60 days. Both ACC and hydrolysis resulted in significantly reduced fiber lengths, with ACC resulting in longer fibrils and fewer negative charges relative to hydrolysis. Moreover, ACC-BNC bioink showed outstanding printability, postprinting mechanical stability, and structural integrity. In vivo, cell-laden structures were rapidly integrated, maintained structural integrity, and showed chondrocyte proliferation, with 32.8 ± 13.8 cells per mm2 observed after 30 days and 85.6 ± 30.0 cells per mm2 at day 60 (p = 0.002). Furthermore, a full-thickness skin graft was attached and integrated completely on top of the 3D-bioprinted construct. The novel ACC disentanglement technique makes BNC biomaterial highly suitable for 3D-bioprinting and clinical translation, suggesting cell-laden 3D-bioprinted ACC-BNC as a promising solution for cartilage repair.

Skin Grafting on 3D Bioprinted Cartilage Constructs In Vivo.

BACKGROUND: Three-dimensional (3D) bioprinting of cartilage is a promising new technique. To produce, for example, an auricle with good shape, the printed cartilage needs to be covered with skin that can grow on the surface of the construct. Our primary question was to analyze if an integrated 3D bioprinted cartilage structure is a tissue that can serve as a bed for a full-thickness skin graft. METHODS: 3D bioprinted constructs (10 × 10 × 1.2 mm) were printed using nanofibrillated cellulose/alginate bioink mixed with mesenchymal stem cells and adult chondrocytes and implanted subcutaneously in 21 nude mice. RESULTS: After 45 days, a full-thickness skin allograft was transplanted onto the constructs and the grafted construct again enclosed subcutaneously. Group 1 was sacrificed on day 60, whereas group 2, instead, had their skin-bearing construct uncovered on day 60 and were sacrificed on day 75 and the explants were analyzed morphologically. The skin transplants integrated well with the 3D bioprinted constructs. A tight connection between the fibrous, vascularized capsule surrounding the 3D bioprinted constructs and the skin graft were observed. The skin grafts survived the uncovering and exposure to the environment. CONCLUSIONS: A 3D bioprinted cartilage that has been allowed to integrate in vivo is a sufficient base for a full-thickness skin graft. This finding accentuates the clinical potential of 3D bioprinting for reconstructive purposes.

Chondrocytes and stem cells in 3D-bioprinted structures create human cartilage in vivo.

Cartilage repair and replacement is a major challenge in plastic reconstructive surgery. The development of a process capable of creating a patient-specific cartilage framework would be a major breakthrough. Here, we described methods for creating human cartilage in vivo and quantitatively assessing the proliferative capacity and cartilage-formation ability in mono- and co-cultures of human chondrocytes and human mesenchymal stem cells in a three-dimensional (3D)-bioprinted hydrogel scaffold. The 3D-bioprinted constructs (5 × 5 × 1.2 mm) were produced using nanofibrillated cellulose and alginate in combination with human chondrocytes and human mesenchymal stem cells using a 3D-extrusion bioprinter. Immediately following bioprinting, the constructs were implanted subcutaneously on the back of 48 nude mice and explanted after 30 and 60 days, respectively, for morphological and immunohistochemical examination. During explantation, the constructs were easy to handle, and the majority had retained their macroscopic grid appearance. Constructs consisting of human nasal chondrocytes showed good proliferation ability, with 17.2% of the surface areas covered with proliferating chondrocytes after 60 days. In constructs comprising a mixture of chondrocytes and stem cells, an additional proliferative effect was observed involving chondrocyte production of glycosaminoglycans and type 2 collagen. This clinically highly relevant study revealed 3D bioprinting as a promising technology for the creation of human cartilage.

In Vivo Chondrogenesis in 3D Bioprinted Human Cell-laden Hydrogel Constructs.

BACKGROUND: The three-dimensional (3D) bioprinting technology allows creation of 3D constructs in a layer-by-layer fashion utilizing biologically relevant materials such as biopolymers and cells. The aim of this study is to investigate the use of 3D bioprinting in a clinically relevant setting to evaluate the potential of this technique for in vivo chondrogenesis. METHODS: Thirty-six nude mice (Balb-C, female) received a 5- × 5- × 1-mm piece of bioprinted cell-laden nanofibrillated cellulose/alginate construct in a subcutaneous pocket. Four groups of printed constructs were used: (1) human (male) nasal chondrocytes (hNCs), (2) human (female) bone marrow-derived mesenchymal stem cells (hBMSCs), (3) coculture of hNCs and hBMSCs in a 20/80 ratio, and (4) Cell-free scaffolds (blank). After 14, 30, and 60 days, the scaffolds were harvested for histological, immunohistochemical, and mechanical analysis. RESULTS: The constructs had good mechanical properties and keep their structural integrity after 60 days of implantation. For both the hNC constructs and the cocultured constructs, a gradual increase of glycosaminoglycan production and hNC proliferation was observed. However, the cocultured group showed a more pronounced cell proliferation and enhanced deposition of human collagen II demonstrated by immunohistochemical analysis. CONCLUSIONS: In vivo chondrogenesis in a 3D bioprinted human cell-laden hydrogel construct has been demonstrated. The trophic role of the hBMSCs in stimulating hNC proliferation and matrix deposition in the coculture group suggests the potential of 3D bioprinting of human cartilage for future application in reconstructive surgery.

Temporary Banking of the Jejunal Flap for a Difficult Esophageal Reconstruction.

In this report, we describe a case of difficult esophageal reconstruction using temporary banking of a jejunal free flap. This flap was temporarily placed on the patient's chest wall using the internal mammary vessels (IMVs) as recipient vessels. After 15 days, the jejunal flap was transferred to the neck region, and permanent coverage was provided using a pedicled latissimus dorsi musculocutaneous flap.

The Aesthetically Ideal Position of the Nipple-Areola Complex on the Breast.

BACKGROUND: Several studies have attempted to identify an objective description of the aesthetically ideal breast, but they have all suffered in their reliability because of having several intrinsic limitations. It is therefore essential to design a template of ideal breast features in order to predict and evaluate aesthetic outcomes in both reconstructive and cosmetic breast surgery. The aim of this study was to determine the aesthetically preferred position of the nipple-areola complex on the breast. METHODS: A questionnaire was sent by regular mail to 1000 men and 1000 women aged between 16 and 74 years. They were asked to rank the attractiveness of a series of breasts of women in images with different NAC positions. The images showed breasts from two different angles: 12 frontal-view images with both breasts shown, and five side-view images with only one breast shown. All of the breasts had equal dimensions and proportions, with the same areola size but different NAC positions. Statistical analysis of data was carried out. RESULTS: Eight hundred and thirteen of 2000 participants completed the questionnaire. The NAC placement preferred by both genders had a ratio of 40:60 x and 50:50 y, which means that it was best situated in the middle of the breast gland vertically and slightly lateral to the midpoint horizontally. Significant differences were found between the age and gender subgroup preferences. CONCLUSIONS: This study identified the preferred position of the nipple-areola complex on the female breast in the general population. This is an important information when planning breast reconstructive and cosmetic surgery. LEVEL OF EVIDENCE II: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

The Effect of Normovolemic and Hypervolemic Hemodilution on a Perforator Flap with Twisted Pedicle Model: Experimental Study in Rats.

BACKGROUND: Several studies showed the detrimental effect of pedicle torsion on flap survival; however, the impact of hemodilution in this peculiar condition has never been investigated. This study evaluated the effect of acute normovolemic and hypervolemic hemodilution on flap survival in a perforator flap with twisted pedicle model. METHODS: Sixty-three female Wistar rats were divided into three groups of 21 rats each: group 1, superficial inferior epigastric artery flap, which was elevated bilaterally and transposed back to the abdominal wall with different angles of rotation (i.e., 90, 180, 270, and 360 degrees); group 2, surgery with previous acute normovolemic hemodilution; and group 3, surgery with previous acute hypovolemic hemodilution. Normovolemic hemodilution was obtained, simultaneously removing 2 cc of blood and replacing it with an equal volume of isotonic sodium chloride 0.9% (two-thirds) plus hydroxyethyl starch 6% (one-third). Hypervolemic hemodilution was obtained by hemodilution and a 20 percent blood volume expansion. Microangiography of the flap and histopathologic analyses were performed. RESULTS: Mean hematocrit values after hemodilution were 27.80 ± 0.04 percent for the acute normovolemic hemodilution group and 27.01 ± 0.03 percent for the acute hypovolemic hemodilution group. Twisting the pedicle at 90, 180, and 270 degrees had no effect on flap survival in all groups. However, 360-degree pedicle torsion showed flap edema, congestion, and necrosis. CONCLUSIONS: The authors' hemodilution protocol is an effective and reliable method that could be used to further investigate the impact of the hemodynamic changes that occur during hemodilution on flap microcirculation. The results obtained sustain the existence of a strong correlation between necrosis rate and hemodilution.

The Effect of Normovolemic and Hypervolemic Hemodilution on a Microsurgical Model: Experimental Study in Rats.

BACKGROUND: Nowadays, postoperative flap perfusion impairment still occurs in free flap surgery; despite several studies on microcirculatory physiology, the effect of hemodilution is still extremely controversial. The aim of this study was to investigate the impact of acute normovolemic and hypervolemic hemodilution on the incidence of flap survival rate in a microsurgical rat model. METHODS: Forty female Wistar rats were divided into four groups of 10 rats each: in group 1, a superficial inferior epigastric artery flap was elevated until femoral vessels were isolated, sectioned, and anastomosed without hemodilution; in group 2, surgery with previous acute normovolemic hemodilution was performed; in group 3, surgery with previous hypervolemic hemodilution was performed; and group 4, was used as a negative control to validate the microsurgical model. Normovolemic hemodilution was obtained, with simultaneous removal of an average of 2.25 cc of blood and replacement with an equal volume of isotonic sodium chloride 0.9 percent and hydroxyethyl starch 6 percent. Hypervolemic hemodilution was obtained by hemodilution and a 20 percent blood volume expansion. Microangiography of the flap and histopathologic analyses were performed. RESULTS: Mean hematocrit values after the hemodilution were 26.80 ± 0.05 percent for group 2 and 28.11 ± 0.04 percent for group 3. Skin flap survival and vascularization after 7 days were significantly higher in both hemodiluted groups compared with the control group (p < 0.05). CONCLUSION: Hemodilution was an effective way of providing better microcirculatory blood perfusion, increasing significantly the flap survival rate in the authors' microsurgical model.

Simplified lipostructure: a technical note.

BACKGROUND: The Coleman technique is universally recognized as the gold standard for fat transfer, but although effective, it is tedious, time consuming, and costly. This report proposes a new and more efficient method of fat grafting (simplified lipostructure). METHODS: This report introduces a modification of the standard Coleman transfer and injection technique, performed by connecting a 10-ml syringe to a 1-ml syringe and to a blunt infiltrating cannula through a "three-way stopcock valve." The study retrospectively evaluated two groups of patients who had undergone either Coleman or simplified lipostructure, comparing surgical staff, operative time, volume of infiltrated fat, cosmetic outcome, and complications. Statistical analyses were conducted using the Wilcoxon rank sum test and Spearman's rank-order correlation. RESULTS: The simplified lipostructure group compared with Coleman lipostructure showed a reduced operative staff (1 vs. 2 members), a reduced operative time (66 vs. 74.2 min) (α = 0.0035), and an increased volume of infiltrated fat (167.2 vs. 138.7 ml) (p < 0.0001) while retaining comparable cosmetic results (7.45 vs. 7.25; visual analog scale 0-10), and only minor complications. CONCLUSION: The three-way stopcock valve system appears to be a smart technical solution that eases syringe refilling, improves fat transplantation times, and reduces costs. The findings show this technical modification to be easy and effective. The authors therefore recommend it to all surgeons performing fat transfer. LEVEL OF EVIDENCE V: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Functional sequelae following bilateral mastectomy and immediate reconstruction with latissimus dorsi flap: medium-term follow-up.

Arm morbidity following unilateral Latissimus Dorsi (LD) flap harvest is controversial and bilateral harvest is considered potentially disabling. Arm and shoulder disability was investigated in patients undergoing bilateral mastectomy and immediate LD flap reconstruction. Thirty consecutive bilateral immediate reconstructions with denervated LD flaps, performed between 2005-2009, were retrospectively analyzed. Patients were assessed for arm function by conducting the Disability of Arm, Shoulder and Hand (DASH) test, between 12-51 months after surgery (mean 23 months). Disability scores ranged from 1-100%, with 1-25% being regarded as mild dysfunction, 26-50% as moderate dysfunction, 51-75% as severe dysfunction, and 76-100% as total dysfunction. A statistical analysis was performed using the Fisher exact test and the multivariate linear regression model for variables. The Global Mean Dash score was 14.8%. Twenty-four patients presented a mild functional deficit (< 25%), while six presented a moderate one (< 50%). Five of them presented a score < 40%, while only one patient presented a score of 49.1%. Higher scores were significantly associated (p < 0.001) with major postoperative complications and lower ones with re-innervated LD flaps (p < 0.01). An insignificant functional impairment was noted in most patients, while a moderate-to-severe one was noted only in the group with complications. Greater impairment is observed in the heavy activities. The DASH test is a useful tool in terms of informing patients and helping the surgeon to choose the best surgical option.

Cutaneous venous malformations related to KRIT1 mutation: case report and literature review.

Cavernous malformations (CMs) are vascular anomalies of the nervous system mostly located in the brain. Cerebral cavernous malformations can present sporadically or familial, as a consequence of an autosomal dominant condition, with incomplete penetrance and variable clinical expression. Occasionally, extraneural manifestations of CMs involving the skin have been described. We report the case of two siblings presenting in adulthood diffuse cutaneous vascular lesions associated with cerebral CMs that, after surgical excision and histopathologic analysis, resulted to cavernous haemangiomas. Genomic DNA was extracted from peripheral blood, and molecular evaluation of KRIT1 gene was performed. Although no signs of neurological impairment were reported, cerebral MRI revealed multiple images in both patients, suggestive of cavernous haemangiomas. The genetic study demonstrated a nonsense mutation (c.535C>T) in the KRIT1 (Krev-1/rap1 interaction trapped 1) gene. Few reports describe extraneural manifestations of Cavernous malformation syndrome (CMs) related to a KRIT1 mutation; these involve the skin and are associated with hyperkeratotic cutaneous capillary-venous malformation. CMs should be suspected in patients developing multiple nodular cutaneous venous lesions in adulthood.

Permanent latissimus dorsi muscle denervation in breast reconstruction.

BACKGROUND: A retrospective analysis of our series of denervated latissimus dorsi (LD) breast reconstructions showed a high incidence of postoperative LD contraction. Anatomical studies with a prospective clinical trial are set up to outline a successful denervation procedure. METHODS: Fifteen fresh cadavers were dissected to study thoracodorsal nerve course. Subsequently, 40 consecutive LD breast reconstructions were divided randomly in equal groups and underwent either distal (group A) or proximal (group B) nerve resection and clipping. The presence of postoperative contraction was evaluated clinically and instrumentally at 2-year follow-up. Statistical analysis of data was performed by Fisher exact test. RESULTS: Cadaver dissections showed distal branching of thoracodorsal nerve in 20% of cases. Incidence of postoperative LD contraction was 35% (7/20) in group A and 0% in group B. A significantly lower rate of contraction in group B was demonstrated (P = 0.004). CONCLUSIONS: Type B proximal nerve resection allows for effective denervation reducing incidence of postoperative contraction (P = 0.004).