Additional Donor Site Morbidity Research Articles

A breast sharing technique using the pedicled IMAP flap for delayed breast reconstruction and contralateral symmetrising mammaplasty: A case series and evolution of the surgical technique in selected patients

IntroductionThe ‘breast-sharing’ procedure uses the disposable tissue as a flap to reconstruct the post-mastectomy defect. This enables simultaneous breast reconstruction and contralateral symmetrisation without additional donor site morbidity. However, controversies related to the oncological safety of this procedure have prevented its widespread uptake. We aim to present this technique based on a pedicled internal mammary artery perforator (IMAP) flap and discuss its technical feasibility and oncological safety. Patients and methodsBetween April 2013 and May 2022, a series of 10 consecutive patients underwent a breast-sharing procedure using the pedicled IMAP flap for breast reconstruction. Clinical and surgical aspects of the breast-sharing procedure were analysed. ResultsIn all cases, the breast-sharing technique allowed for simultaneous breast reconstruction and contralateral breast symmetrisation. Immediate complications included two total venous congestions and one hematoma. Three flaps had distal flap congestion. One flap required debridement and local flap reconstruction. All flaps required fat grafting during the secondary procedures to improve breast symmetry. With an average follow-up of 5,6 years, there was no evidence of recurrent disease. All patients were satisfied to very satisfied with the aesthetic outcome of this reconstructive option. ConclusionsThe breast-sharing technique based on the IMAP flap combines breast reconstruction and contralateral symmetrisation with good aesthetic outcomes in selected patients. The flap has a high complication rate related to venous drainage. Flap design modification and using ICG imaging may reduce venous congestion. A secondary venous micro-anastomosis at the axilla is highly recommended for persistent flap congestion. The reported incidence of contralateral breast cancer is low and thus the residual tissue obtained from the contralateral breast mammaplasty can be safely used for breast reconstruction. Level of EvidenceLevel IV

Fillet of toe flap coverage for non-traumatic foot amputations: A retrospective review of 70 patients

Fillet of toe flap (FTF) leverages the “spare parts” algorithm in reconstructive surgery–utilizing tissue from amputated or otherwise non-salvageable body parts, thus avoiding donor-site morbidity. This study assesses the efficacy of FTF coverage in non-traumatic foot amputations. A retrospective review of patients undergoing foot amputation with FTF coverage between January 2013 to August 2023 was conducted. Patient characteristics, operative details, and outcomes were collected. Primary outcome was FTF survival (no necrosis ≤7 days postoperatively). Secondary outcome was acute complications (≤42 days postoperatively). A total of 70 patients were included. Mean age was 65.0±13.7 years. Median Charlson Comorbidity Index was 6.0 (interquartile range [IQR]: 4.0-7.0). The most common wound location was the hallux (n=34). In 45 (64.2 %) patients with preoperative angiography, the patency rates were: first dorsal metatarsal artery (n=10, 22.2 %), lateral plantar artery (n=7, 15.6 %), medial plantar artery (n=6, 13.3 %), and dorsalis pedis artery (n=4, 8.9 %). Mean follow-up duration was 9.0 (IQR: 32) months. Fifteen (21.4 %) patients experienced at least one acute complication: deep surgical site infection (SSI; i.e., abscess, gangrenous necrosis; n=13, 18.6 %) and cellulitis (n=7, 10.0 %). Eleven (15.7 %) patients required reoperation for debridement (n=4, 5.7 %), wound closure (n=4, 5.7 %), flap necrosis (n=3, 4.3 %), incision and drainage (n=1, 1.4 %), split-thickness skin grafting (n=1, 1.4 %), and foreign body exploration (n=1, 1.4 %). FTF survival was 94.2 % (n=66). FTF facilitates reconstruction in complex cases and should be integrated into each chronic LE wound algorithm to avoid additional donor-site morbidity, and to facilitate stump-length preservation or limb salvage.

Tissue Options for Construction of the Neovaginal Canal in Gender-Affirming Vaginoplasty.

Gender-affirming vaginoplasty (GAV) comprises the construction of a vulva and a neovaginal canal. Although technical nuances of vulvar construction vary between surgeons, vulvar construction is always performed using the homologous penile and scrotal tissues to construct the corresponding vulvar structures. Therefore, the main differentiating factor across gender-affirming vaginoplasty techniques is the tissue that is utilized to construct the neovaginal canal. These tissue types vary markedly in their availability, histology, and ease of harvest and have different advantages and disadvantages to their use as neovaginal lining. In this narrative review, the authors provide a comprehensive overview of the tissue types and associated operative approaches used for construction of the neovagina in GAV. Tissue choice is guided by several factors, such as histological similarity to natal vaginal mucosa, tissue availability, lubrication potential, additional donor site morbidity, and the specific goals of each patient. Skin is used to construct the neovagina in most cases with a combination of pedicled penile skin flaps and scrotal and extra-genital skin grafts. However, skin alternatives such as peritoneum and intestine are increasing in use. Peritoneum and intestine are emerging as options for primary vaginoplasty in cases of limited genital skin or revision vaginoplasty procedures. The increasing number of gender-affirming vaginoplasty procedures performed and the changing patient demographics from factors such as pubertal suppression have resulted in rapidly evolving indications for the use of these differing vaginoplasty techniques. This review sheds light on the use of less frequently utilized tissue types described for construction of the neovaginal canal, including mucosal tissues such as urethral and buccal mucosa, the tunica vaginalis, and dermal matrix allografts and xenografts. Although the body of evidence for each vaginoplasty technique is growing, there is a need for large prospective comparison studies of outcomes between these techniques and the tissue types used to line the neovaginal canal to better define indications and limitations.

Dorsal V-Y Advancement Flap for Lateral Finger Defect Based on Dorsal Skin Branch of Proper Digital Artery.

Managing lateral soft tissue defects, distal to the proximal interphalangeal joint, of the finger can be challenging. The use of antegrade homodigital island flap can be limited due to the length of the defect. Using a heterodigital island flap can be precluded by an injury in the adjacent fingers. Using the locoregional flap from the hand can result in a more extensive soft tissue dissection, which can create additional donor site morbidity. We present our execution technique of the homodigital dorsal skin advancement flap. The pedicle of the flap is based on dorsal branches of the digital artery perforator; hence the proper digital artery and nerve are unharmed. The operation is limited only to the injured digit, which can reduce donor site morbidity.

Fasciocutaneous Free Tissue Transfer in Limb Salvage: Prior Flap as a Split-thickness Skin Graft Donor Site.

Free flap surgery for limb salvage has become the surgical standard for reconstruction of bone and soft tissue with success rates and flap survivals of 94%-95%. The soft tissue defect dictates the technique of coverage. In many cases, multiple techniques of soft tissue coverage are necessary, ranging from myocutaneous and fasciocutaneous free flaps to split-thickness skin grafts (STSGs). It has been shown that fasciocutaneous free flaps are not inferior to muscle flaps in treatment of lower leg limb salvage. Although a complete flap loss is rare, it is not uncommon to have partial flap necrosis, wound dehiscence, or secondary soft tissue defects, necessitating further minor reconstruction, which we call "touch up" skin grafts. In many of these secondary procedures, split thickness skin grafts are sufficient. We have been using the skin portion of the fasciocutaneous free flap as a donor site for harvesting STSGs for quite some time without disadvantages. We believe that minimizing additional donor site morbidity is of great importance. The free tissue transfer is insensate and readily available at the site of injury, making prepping and draping simple as well as cosmetically acceptable, as the transferred free tissue, unfortunately, is rarely a perfect fit. The associated pain, discomfort, and scar of an additional donor site can be avoided. In our case series, we did not experience any flap loss, infections, or complications. Thus, harvesting an STSG from a fasciocutaneous free flap seems to be a feasible option to be considered in limb salvage.

Pectoralis major pedicle bone grafting vs. tricortical iliac grafting for Neer 4-part proximal humerus fractures: a randomized controlled trial

The risk of avascular necrosis, nonunion, or malunion is high in osteoporosis-related 4-part fractures. We tried to evaluate the results of patients who underwent plate osteosynthesis with vascularized pectoralis major graft comparing with tricortical iliac grafting to treat 4-part proximal humerus fractures. Thirty-four patients aged 50-75 with Neer 4-part proximal humerus fractures were studied. Group A (n=17) underwent osteotomy of a 2.5cm±1cm pectoralis major pedicle bone graft and plate application, while Group B (n=17) underwent plate osteosynthesis using iliac autogenous grafts. Final follow-up assessments included evaluation using Constant and American Shoulder and Elbow Surgeons scoring systems, Humeral Neck-Shaft Angle (HNSA), humeral head height (Humeral Head Height) and humeral head avascular necrosis. Although reduction loss was observed in 3 patients (17.6%) in Group A patients, reduction loss was observed in 10 patients (58.8%) in Group B., p= 0.013. Humeral head avascular necrosis was 1 (5.8%) in Group A, while it was 5 (29.4%) in the other group (p= 0.071). The HNSA was normal in 12 (70.5%) of Group A patients, while it was normal in 6 (35.2%) of Group B patients. The HNSA was weak or bad (<1200) in 29.4% of Group A patients, while this rate was 64.7% in Group B patients. HHH was 2.64±1.45 mm in Group A and 3.66±1.65 mm in Group B. There were no statistically significant differences between the two groups in terms of Constant and American Shoulder and Elbow Surgeons scoring systems. Pectoralis major bone pedicle graft in Neer 4-part proximal humerus fractures reduces the risk of avascular necrosis and nonunion rates. Our technique yielded excellent clinical and radiological results. We achieved recovery without creating additional donor site morbidity.

Meniscus Allograft Transplantation Augmented With Autologous Bone Marrow Aspirate Concentrate

Meniscus allograft transplantation (MAT) has been shown to be a feasible surgical option for younger patients, below 50 years of age who have meniscal insufficiency and have failed conservative treatment measures. In this technical note, we describe a procedure of harvesting and injecting bone marrow aspirate concentrate in a meniscus allograft during a MAT procedure, which may allow for longer lasting transplants and improve patient outcomes. In this technical note, bone marrow aspirate concentrate is harvested arthroscopically from the intercondylar notch at the surgical site, which prevents additional donor site morbidity, as seen with harvesting from other locations, such as the iliac crest. This also reduces operating time, since harvesting from the iliac crest requires different patient positioning and usually additional anesthesia. The authors of this surgical technique believe that biological augmentation during MATs will assist surgeons in maximizing graft survivorship and, ultimately, lead to better patient outcomes.

Determining the Gold Standard for Peripheral Nerve Management in Traumatic Amputations

Objective: Traumatic amputations and postamputation pain are common. Various surgical techniques have been explored to prevent and treat neuromas. Despite multiple methods for management of the nerve stumps in amputations, there is no operative gold standard. A new technique, regenerative peripheral nerve interface (RPNI), has been described with excellent early outcomes. This technique uses a muscle or skin graft for treatment of, or prophylaxis against, neuroma development. There have been no randomized, controlled trials demonstrating the superiority of RPNI compared to traditional surgical techniques. We hypothesize the RPNI construct will be superior in preventing neuroma development, neuroma tenderness, and hyperalgesia than the control or traditional methods. Methods: We employed a rat model of nerve amputation. One of three treatment groups were randomly assigned to each rat hindlimb: a positive control group in which the nerve was transected and sewn directly into the overlying skin, a traditional group where the nerve was transected and implanted into the biceps femoris muscle, and the experimental group where a muscle RPNI construct was created. Behavioral analysis was performed assessing mechanical hyperalgesia, tactile hyperalgesia, and neuroma tenderness on a weekly basis. After eight weeks of recovery, the rats were euthanized and the nerve sent for histologic analysis. Statistical analysis was done with 2-way repeated measures ANOVA and a logistic regression with MedCalc software. Results: There were no statistically significant differences in any of the treatment groups in mechanical hyperalgesia, tactile hyperalgesia, neuroma tenderness, or weight change. There were significant changes in these metrics over the course of the study, but no difference in these changes between the treatment groups. Excised transected nerve and nerve targets from the experimental animals showed minimal differences in neuroma formation. Each RPNI remained viable and vascularized. Conclusion: This study did not demonstrate any significant differences between the treatment groups. Burying a transected peripheral nerve into muscle as well as wrapping the nerve with an RPNI construct are both suitable options for prevention of neuroma development. The behavioral analysis did not show any significant differences between the positive control group and the experimental groups. This may be explained by the panniculus carnosus, a dermal muscular layer found in rats. It is a distinct muscular layer that could explain why the rate of neuroma formation in the positive control group did not have 100% permeance, as originally hypothesized. This layer may have acted as a second implantation into muscle group, rather than a positive control. Additionally, an eight-week recovery period may have been insufficient to detect behavioral differences amongst the groups. Further research should be done to analyze systemic inflammatory changes as well as analyze how different constructs could be used to wrap around a nerve stump without causing additional donor site morbidity. Corresponding author: Elizabeth Lucich, [email protected]

Successful Treatment of a Painful Neuroma Using Fascicular Shifting in the Ulnar Nerve: A Case Report

Abstract Objective We report the case of a 40-year-old man with an inveterate ulnar nerve neuroma following a laceration injury of his left wrist twenty-three years ago. The patient presented with a typical ulnar claw-hand deformity and debilitating neuropathic pain in his hand (VAS 8.4). Pre-operative imaging revealed a neuroma of the ulnar nerve at the Guyon's canal. Moreover, a complete atrophy of all intrinsic hand muscles innervated by the ulnar nerve was present. Methods A Zancolli lasso procedure was performed to reduce the clawing effect. The neuroma was resected producing a nerve defect of five centimeters. Since the injury dated back more than two decades and any motor recovery was deemed impossible at that point, the motor fascicle of the ulnar nerve, i.e. the deep branch, was selectively neurolysed and harvested as an autologous nerve graft. Then the graft was shifted into the defect to be coapted with the superficial branch fascicle in an end-to-end fashion. Results The presented fascicular shift procedure resulted in satisfying and sustained pain reduction. At the six-month follow-up, the VAS decreased to 1.2, and two years post-operatively, the patient reported 2.5 on the VAS. Conclusion The fascicular shift procedure offers an alternative approach to conventional nerve grafts. If nerve grafting is required, using a locally harvested graft avoids additional donor site morbidity. Assuming the clinical scenario allows for fascicular grafting, we strongly suggest considering the fascicular shift procedure as a cost-effective alternative to expensive conduits and processed nerve allografts in sensory nerve reconstruction.

Single-Layer Acellular Porcine Bladder Matrix as Graft in Corporoplasty for Ventral Curvature in Pediatric Proximal Hypospadias Repair: An Initial Experience

Single-layer ACell Cytal matrix (ACell Inc, Columbia, MD) is a commercially available, acellular scaffold derived from porcine bladder epithelial basement membrane and tunica propria. We describe our initial experience using Cytal as corporal graft in pediatric patients who underwent correction of ventral curvature in proximal hypospadias repair. A retrospective review of a single-institution, 4 surgeon hypospadias database was performed between January 2020 and December 2021. Outcomes assessed were postoperative recurrent ventral curvature, corporal diverticulum, scarring on corporoplasty site on physical exam, and parental reports of atypical adverse effects. Ten males underwent correction of ventral curvature with Cytal as corporal graft for correction of ventral curvature were identified. All completed planned operations. Median age was 18.6 months (IQR 14.6-27.0). Median follow up was 14.1 months (IQR 8.9-16.5). Mean ventral curvature after degloving was 80 ± 50 degrees. All patients had straight erections. Nine of the 10 patients had straight erections verified at a subsequent artificial erection test at least 6 months from the corporoplasty (90%). The remaining patient underwent a double face onlay-tube-onlay transverse island preputial flap as a single-stage hypospadias repair and did not require any additional procedures. He had straight erections per parental history. None developed corporal diverticulum or demonstrated induration at site of corporoplasty on physical exam. There were no parental reports of atypical adverse systemic effects. In the short term, single-layer Cytal is effective as corporal graft for correction of ventral curvature in proximal hypospadias repairs without incurring additional donor site morbidity.

Short Stay Management of Locally Advanced Breast Cancer Using Immediate Local Thoracoabdominal Advancement Flap and Enhanced Recovery After Surgery Protocol.

Patients with locally advanced invasive breast cancer (LABC) are often considered inoperable, because of the anticipated chest wall defect and need for complex reconstruction. We present a series of patients who underwent mastectomy with extensive skin resection and immediate chest wall reconstruction using a local thoracoabdominal advancement flap (TAAF). All patients were managed after surgery with an ERAS (Enhanced Recovery After Surgery) protocol, to decrease length of stay in hospital. We also present 1 patient who subsequently had satisfactory bilateral delayed breast reconstruction with pedicled latissimus dorsi myocutaneous flaps with prepectoral silicone implants. This is a single-surgeon, single-institution retrospective chart review of patients with LABC who underwent mastectomy with skin resection and local TAAF from May 2017 to October 2019, with minimum 3-month follow-up. Thirteen patients met inclusion criteria. Twelve of 13 patients presented with stage III or IV invasive breast cancer, with skin involvement. The mean chest wall defect measured 248.7 cm2 (140-336 cm2; SD, 63.2 cm2), and all were successfully reconstructed with immediate local TAAF. There were no intraoperative complications, but 1 patient developed a postop hematoma. The mean hospital stay was 1.3 nights, with 9 patients (69.2%) staying less than 23 hours and 4 patients (30.8%) staying 2 nights. Nine patients (69.2%) underwent adjuvant therapy, beginning on average 32 days (13-55 days; SD, 13.1 days) after surgery. The mean follow-up time was 13.8 months (4.5-31.6 months; SD, 9.2 months). One patient underwent successful delayed bilateral breast reconstruction with pedicled latissimus dorsi myocutaneous flaps and silicone implant placement. Our study demonstrates that reconstruction with local TAAF is an outpatient procedure that reliably provides durable, immediate chest wall coverage, after mastectomy in patients with LABC. This technique has a short operative time, low blood loss, and low complication rate, allowing timely adjuvant therapy. Using an ERAS postop protocol we were able to reduce mean hospital stay to 1.3 days. Compared with other described techniques of reconstruction, the additional scars and donor site morbidity are minimal, allowing for delayed breast reconstruction. We also present survival outcomes data on these surgically managed patients.

Assessment of Two Commonly used Dermal Regeneration Templates in a Swine Model without Skin Grafting

In the medical care of partial and full-thickness wounds, autologous skin grafting is still the gold standard of dermal replacement. In contrast to spontaneous reepithelializing of superficial wounds, deep dermal wounds often lead to disturbing scarring, with cosmetically or functionally unsatisfactory results. However, modern wound dressings offer promising approaches to surface reconstruction. Against the background of our future aim to develop an innovative skin substitute, we investigated the behavior of two established dermal substitutes, a crosslinked and a non-crosslinked collagen biomatrix. The products were applied topically on a total of 18 full-thickness skin defects paravertebrally on the back of female Göttingen Minipigs—six control wounds remained untreated. The evaluation was carried out planimetrically (wound closure time) and histologically (neoepidermal cell number and epidermis thickness). Both treatment groups demonstrated significantly faster reepithelialization than the controls. The histologic examination verified the highest epidermal thickness in the crosslinked biomatrix-treated wounds, whereas the non-crosslinked biomatrix-treated wounds showed a higher cell density. Our data presented a positive influence on epidermal regeneration with the chosen dermis substitutes even without additional skin transplantation and, thus, without additional donor site morbidity. Therefore, it can be stated that the single biomatrix application might be used in a clinical routine with small wounds, which needs to be investigated further in a clinical setting to determine the size and depths of a suitable wound bed. Nevertheless, currently available products cannot solely achieve wound healing that is equal to or superior to autologous tissue. Thus, the overarching aim still is the development of an innovative skin substitute to manage surface reconstruction without additional skin grafting.

Use of Biologic Agents in Nasal and Scalp Reconstruction.

Oncologic reconstruction of the nose and scalp following Mohs micrographic surgery poses a significant challenge for plastic surgeons. While these defects are traditionally reconstructed using primary closure techniques, skin grafts, local flaps, pedicled flaps, and free tissue transfer, the incorporation of biologic healing wound agents such as Integra and Cytal provides patients and surgeons with alterative reconstructive options without additional donor site morbidity. Herein, we review the use of biologic agents used in soft tissue reconstruction of the nose and scalp following Mohs surgery.

A New Strategy for Patient-Specific Implant-Borne Dental Rehabilitation in Patients With Extended Maxillary Defects.

Purpose of the StudyPatients undergoing ablative tumor surgery of the midface are faced with functional and esthetic issues. Various reconstructive strategies, such as implant-borne obturator prostheses or microvascular tissue transfer, are currently available for dental rehabilitation. The present study shows the first follow-up of patients treated with patient-specific implants (IPS Implants® Preprosthetic) for the rehabilitation of extended maxillary defects following ablative surgery.Patients and MethodsAll patients treated with patient specific implants due to postablative maxillary defects were included. 20 implants were placed in the 19 patients (bilateral implants were placed in one of the cases). In 65.75% of the cases, resection was performed due to squamous cell carcinoma. In addition to the primary stability, the clinical implant stability, soft tissue management, successful prosthodontic restoration, and complications were evaluated at a mean follow-up period of 26 months.ResultsAll patient-specific implants showed primary stability and were clinically stable throughout the observation period. Definitive prosthodontic restorations were performed in all patients. No implant loosening was observed. Major complications occurred only in previously irradiated patients with insufficient soft tissue conditions (p = 0.058). Minor complications such as exposure of the underlying framework or mucositis were observed, but they never led to failure of restorations or implant loss.ConclusionsTreatment of postablative maxillary defects with patient-specific implants offers a safe alternative with predictable results for full and rapid dental rehabilitation, avoiding time-consuming augmentation procedures and additional donor-site morbidity.

Systematic review and meta-analysis of surgical options for recurrent or persistent carpal tunnel syndrome: simple decompression versus coverage of the median nerve.

We performed a systematic review on the success of different surgical techniques for the management of recurrent and persistent carpal tunnel syndrome. Twenty studies met the inclusion criteria and were grouped by the type of revision carpal tunnel release, which were simple open release, open release with flap coverage or open release with implant coverage. Meta-analysis showed no difference, and pooled success proportions were 0.89, 0.89 and 0.85 for simple open carpal tunnel release, additional flap coverage and implant groups, respectively. No added value for coverage of the nerve was seen. Our review indicates that simple carpal tunnel release without additional coverage of the median nerve seems preferable as it is less invasive and without additional donor site morbidity. We found that the included studies were of low quality with moderate risk of bias and did not differentiate between persistent and recurrent carpal tunnel syndrome.

External oblique muscle flap for abdominal wall reconstruction: Local solution for local problem

Reconstruction of full-thickness abdominal wall defect is difficult and is usually done by regional flaps or free tissue transfers. This creates additional donor site morbidity. A 20 cm × 15 cm full-thickness defect in the right iliac fossa of a woman after tumor excision was reconstructed successfully with right-sided external oblique muscle flap and abdominoplasty in a hitherto undescribed fashion. External oblique muscle flap with abdominoplasty can be used for reconstruction of abdominal wall defects with minimum morbidity and satisfactory esthetic appearance.

The Spare Parts Concept in Sarcoma Surgery: A Systematic Review of Surgical Strategies

Main treatment for limb sarcomas is surgical resection with negative tumoral margins. In cases in which tumor removal requires limb amputation, tissues free of infiltration can be used as flaps – be they free or pedicled – with reconstructive aim or to obtain an optimal proximal stump, according to “spare parts surgery” concept. The application of these strategies avoids causing additional donor-site morbidity with a reconstructive objective, as well as facilitating the subsequent process of prosthetization and functional rehabilitation. This article aims to review the main techniques encompassed in this concept, incorporating our own-experience tips on its surgical approach.

The Microsurgical Calcaneus Osteocutaneous Fillet Flap After Traumatic Amputation in Lower Extremities: Flap Design and Harvest Technique.

Attempts to salvage upper and lower extremities have performed more frequently in recent decades, although there are clear cases that cannot be salvaged. The purpose of this retrospective study was to present our experience in using free calcaneus osteocutaneous fillet flap for preserving below-knee amputation stump after traumatic amputations or functional preserving after nonsalvageable lower extremities. Between January 2012 and May 2017, 11 free calcaneus osteocutaneous fillet flap were used to preserving or lengthening below-knee amputation stump secondary to amputation on 8 males and 3 females. Patients' information and postoperative data were collected, including age of patient, sex, amputation site, flap survival, sensation recovery, and number of complications. All amputations were trauma related and secondary to motor vehicle accidents (n = 8) and industrial accidents (n = 3). The age of the patients ranged from 16 to 59 years, with a mean of 34.4 years. Free calcaneus osteocutaneous fillet flap were designed and harvested from all patients. All flaps survived and 2 complications developed in 2 patients. Nine of 11 patients obtained protective sensory recovery during the period of follow-up. The free calcaneus osteocutaneous fillet flap harvested from the amputated limb provides reliable and robust tissue for reconstruction of large defects of the residual limb without additional donor-site morbidity.

Demineralized Dentin Matrix (DDM) As aCarrier for Recombinant Human Bone Morphogenetic Proteins (rhBMP-2).

A bone graft and bone graft substitute should have at least one of the following properties: it should be (1) osteogenic, (2) osteoinductive and/or (3) osteoconductive. In addition, bone graft substitutes should be biocompatible and bioresorbable as well as easy to use and cost effective. Autologous cancellous bone is the clinical gold standard in bone grafting procedures1, 4 and it has osteogenic, osteoinductive, and osteoconductive properties. Because of disadvantages associated with harvesting autologous bone graft material, such as requiring an additional operation and possible donor site morbidity, there is a need for an alternative in terms of enhancing the bone healing for the treatment of large bony defects. One possible option is a newly developed biomaterial, the demineralized dentin matrix (DDM). It is based on autogenous tooth dentin and is produced through demineralization. It is osteoconductive and osteoinductive due to the fact that dentin contains extracellular Type I collagen and various growth factors. Based on the demineralization process the factors stay available to the host environment. In 1965, Urist already showed the formation of ectopic bone after implanting DDM into muscle pouches in rodents. DDM is used for example in dental surgery in the treatment of extraction socket preservation and guided bone regenerations. It functions as a scaffold to support bone regeneration, but can also be used as a carrier for rhBMP-2. When DDM serves as a carrier, it combines the properties of the grafting material with those of the delivered substances. This chapter will present the experimental and clinical studies of DDM for rhBMP-2 carrier as well as alternatives of bone graft substitute.

Fascicular shifting: a novel technique to overcome large nerve defects.

OBJECTIVE Over the last decade, a number of authors have investigated the utility of different biological and synthetic matrices as alternatives to conventional nerve grafts. However, the autologous nerve graft remains the gold standard, even though it often involves using a pure sensory nerve to reconstruct a mixed or even a pure motor nerve. Furthermore, limited donor sites often necessitate a significant mismatch of needed nerve tissue, especially for large proximal nerve defects such as brachial plexus lesions. Here, the authors present a new technique that overcomes these problems: the fascicular shift procedure (FSP). A fascicular group of the nerve distal to the injury is harvested in a sufficient length to bridge the nerve defect. METHODS The method of fascicular shifting was tested at the sciatic nerve in 45 Lewis rats. In the experimental group, a 15-mm nerve defect was created and reconstructed with a fascicular group that was harvested directly distal to the gap. This group was compared with 1 negative control group (defect without reconstruction) and 3 positive control groups (sensory, motor, and mixed graft). After 12 weeks of nerve regeneration, outcome was evaluated using retrograde labeling, histomorphometric analysis, and muscle force analysis. RESULTS All reconstructed groups showed successful regeneration with various levels of function. The negative control group showed minimal force measurements that were of no functional value. The fascicular shift provided sufficient guidance to overcome nerve defects, had higher (p < 0.1) motor neuron counts (1958.75 ± 657.21) than the sensory graft (1263.50 ± 538.90), and was equal to motor grafts (1490.43 ± 794.80) and mixed grafts (1720.00 ± 866.421). This tendency of improved motor regeneration was confirmed in all analyses. The mixed graft group was compared with the experimental group to investigate the influence of the potential damage induced by the fascicular shift distal to the repair site. However, none of the analyses revealed an impairment of nerve regeneration for both the tibial and common peroneal index muscles. CONCLUSIONS This study demonstrates that harvesting a transplant from the nerve segment distal to the injury site offers a mixed graft without causing additional donor-site morbidity. These grafts perform statistically better than a standard sensory graft in terms of motor recovery. The fascicular shift presents a novel method to reconstruct large proximal nerve defects, making it immensely attractive in brachial plexus reconstruction.