Shaun D. Mendenhall

The course of the frontal branch of the facial nerve in relation to fascial planes: an anatomic study.

Background: Despite a wealth of literature describing the anatomy of the temporal region, controversy still exists over the depth of the frontal branch of the facial nerve as it travels over the zygomatic arch. It is commonly stated that the frontal branch travels within the superficial musculoaponeurotic system (SMAS) as it crosses the zygomatic arch. Clinically, however, it is apparent that the nerve runs at a deeper level as it crosses the arch, allowing for safe elevation and division of the SMAS to a point at or above the superior border of the zygomatic arch. The purpose of this study was to define the path of the frontal branches along fascial planes and to clarify the relationship of the fascial layers of the cheek and temporal region. Methods: Eighteen fresh-frozen cadaver hemifaces were dissected in a layer-by-layer fashion to evaluate the relationship between the nerve and the fascial planes above and below the zygomatic arch. Histologic evaluation was performed on six hemifaces. Results: In all dissections, the frontal branch traveled within the innominate fascia as it crossed the zygomatic arch into the temporal region. A fascial transition zone was identified in a region 1.5 to 3.0 cm above the zygomatic arch and 0.9 to 1.4 cm posterior to the lateral orbital rim, where the frontal branches crossed from the innominate fascia to run within the superficial temporal fascia. Conclusion: As the frontal branch crosses the zygomatic arch, it is within the innominate fascia, a plane deep to the SMAS and superficial temporal fascia.

Side-to-side nerve bridges reduce muscle atrophy after peripheral nerve injury in a rodent model

BACKGROUND Peripheral nerve injury can result in muscle atrophy and long-term disability. We hypothesize that creating a side-to-side bridge to link an injured nerve with a healthy nerve will reduce muscle atrophy and improve muscle function. METHODS Sprague-Dawley rats were divided into four groups (n = 7 per group). Group 1: transection only--a 10-mm gap was created in the proximal tibial nerve; group 2: transected plus repaired--the transected tibial nerve was repaired; group 3: transected plus repaired plus nerve bridge--transected nerve repaired with a distal nerve bridge between the tibial and peroneal nerves via epineurial windows; and group 4: transected plus nerve bridge--transected tibial nerve left unrepaired and distal bridge added. Gait was assessed every 2 wk. At 90 d the following measures were determined: gastrocnemius mass, muscle and nerve nuclear density, and axonal infiltration into the nerve bridge. RESULTS Groups 3 and 4 had greater improvements in walking track recovery than groups 1 and 2. Group 3s gastrocnemius muscles exhibited the least amount of atrophy. Groups 1, 2, and 4 exhibited greater histologic appearance of muscle breakdown compared with group 3 and control muscle. Finally, most bridges in groups 3 and 4 had neuronal sprouting via the epineurial windows. CONCLUSIONS Our study demonstrated reduced muscle atrophy with a side-to-side nerve bridge in the setting of peripheral nerve injury. These results support the application of novel side-to-side bridges in combination with traditional end-to-end neurorrhaphy to preserve muscle viability after peripheral nerve injuries.

Aseptic versus Sterile Acellular Dermal Matrices in Breast Reconstruction: An Updated Review

Background: As the use of acellular dermal matrices in breast reconstruction has become more commonplace and efforts are made to improve on postoperative outcomes, the method of acellular dermal matrix (ADM) processing (aseptic versus sterile) has become a subject of interest. This article provides an updated overview of the critical aspects of ADM processing in addition to application of ADMs in single- and two-stage breast reconstruction, a review of the morbidity associated with ADM use, and alternatives. Methods: A literature review was performed in PubMed identifying recent systematic reviews, meta-analyses, and head-to-head comparisons on aseptically processed ADM and sterile-processed ADM in implant-based breast reconstruction. Results: Recent meta-analyses have shown a 2- to 3-fold increase in infections and tissue expander/implant explantation rates and a 3- to 4-fold increase in seroma formation compared with non-ADM reconstruction techniques. Comparisons of aseptic and sterile ADMs in multiple studies have shown no significant difference in infection rates and equivocal findings for other specific complications such as seroma formation. Conclusions: Current evidence on the impact of processing techniques that improve ADM sterility on postoperative morbidity in implant breast reconstruction is unclear. Deficiencies of the available data highlight the need for well-designed, multicenter, randomized controlled studies that will aid in optimizing outcomes in implant-based breast reconstruction.

Osteosynthesis in Forearm Transplantation Using a Novel Ulnar-Shortening Osteotomy System for Simultaneous Both Bone Fixation

Introduction: Osteosynthesis in forearm-level allotransplantation is technically challenging. Achieving adequate cortical contact simultaneously between the radius and ulna proves difficult due to differing bone morphology of donor and recipient. In addition, the large area of dissection around the osteotomy sites and use of immunosuppressants further deters osseous healing, making nonunion a significant risk. Methods: Seven distal forearm transplants were performed on cadavers using the Newclip Technics ulnar-shortening osteotomy system for both the radius and ulna. The donor bones were plated after placing two transverse 0.062 K-wires distally for DRUJ stabilization. The osteotomy cut-guides were screwed to the plates and oblique osteotomies were performed. Matching recipient osteotomies were performed using the same cut-guide system. The donor and recipient were then brought together and any discrepancies in length corrected. The osteosynthesis site is then compressed and an interfragmentary lag screw placed across the osteosynthesis. Results: The Newclip system enables precise osteosynthesis in cadaver distal forearm transplants. Targeted radial and ulnar lengths are reliably achieved while maintaining accurate control of ulnar variance. Multiple osteotomy slot options on the cut guides allow titration of bone length. Oblique osteotomies enable increased cortical contact and an interfragmentary lag screw for additional stabilization. Conclusions: The capability to perform osteotomies, compression, and fixation of both radius and ulna simultaneously using this technique allows for reliable and precise hand transplantation osteosynthesis. This technique will be an effective tool until patient-specific instrumentation derived from computer-aided design can be expeditiously manufactured and made widely available.

The BREASTrial Stage II: ADM Breast Reconstruction Outcomes from Definitive Reconstruction to 3 Months Postoperative.

Background: The Breast Reconstruction Evaluation of Acellular Dermal Matrix as a Sling Trial is a prospective randomized trial comparing outcomes of tissue expander breast reconstruction using either AlloDerm or DermaMatrix. The trial was divided into 3 outcome stages; this study reports stage II outcomes, which are those from the time of definitive reconstruction to 3 months postoperative. Methods: A randomized trial was conducted to compare complication rates between AlloDerm and DermaMatrix groups. The impact of matrix type, age, obesity, radiation therapy, chemotherapy, and reconstruction type on complications was analyzed with regression models. Results: Of the 128 patients (199 breasts) who were randomly assigned into the trial, 111 patients (173 breasts) were available for analysis in stage II. There was no difference in overall rates of complications (15.4% vs 18.3%, P = 0.8) or implant loss (2.2% vs 3.7%, P = 0.5) between the AlloDerm and DermaMatrix groups, respectively. Obesity was the only significant predictor of complications on regression analysis (odds ratio, 4.31, P = 0.007). Matrix type, age, radiation therapy, chemotherapy, or reconstruction type had no impact on the incidence/severity of complications. Conclusions: Acellular dermal matrix (ADM) will likely continue to have a role in breast reconstructive surgery; however, caution should be taken when using ADM because of relatively high complication rates, especially in obese patients. The particular ADM product should be selected based on individual surgeon preference, experience, and success rates. These data and forthcoming long-term outcomes from the Breast Reconstruction Evaluation of Acellular Dermal Matrix as a Sling Trial will enable surgeons to carefully weigh the risks and benefits of ADM use in breast reconstruction.

Defining the Salvage Time Window for the Use of Ischemic Postconditioning in Skeletal Muscle Ischemia Reperfusion Injury.

BACKGROUND The aim of this study was to determine the optimal salvage time window within which ischemic postconditioning can be used to ameliorate ischemia/reperfusion (I/R) injury in skeletal muscle. METHODS A total of 48 Sprague-Dawley rats were divided into two groups: I/R only (control) and I/R with postconditioning. Subgroups were divided by duration of ischemia (2, 4, 6, and 8 hours). A pedicled gracilis muscle model was used. The postconditioning protocol consisted of six cycles of 15 seconds of reperfusion followed by 15 seconds of ischemia (total time = 3 minutes). Muscles were harvested 24 hours after I/R injury to examine tissue viability, histology, myeloperoxidase activity, and protective gene expression. RESULTS Postconditioning groups showed improved muscle viability after 4 and 6 hours of ischemia time as compared with controls (p < 0.05). Higher expression of mitochondrial complexes I, II, III, endothelial nitric oxide synthase, inducible nitric oxide synthase, and Bcl-2 were observed in the postconditioning group after 4 and 6 hours of ischemia (p < 0.05). Lower expression of tumor necrosis factor-α and caspase 3 was observed in the postconditioning group at 4 hours (p < 0.05). Myeloperoxidase activity was similar in both groups at all-time points except 8 hours ischemia, where the control group had higher activity (p < 0.05). CONCLUSION Results of this study demonstrate that the effective time window within which postconditioning is most effective for the salvage of skeletal muscle is between 4 and 6 hours of ischemia. Postconditioning offered improved mitochondrial and vascular function with decreased inflammation and cell death. This may be clinically useful as a postinjury salvage technique to attenuate I/R injury after 4 to 6 hours of ischemia.

Clinical Application of Mathematical Long Bone Ratios to Calculate Appropriate Donor Limb Lengths in Bilateral Upper Limb Transplantation

Background: Limited methods exist to aid in deciding the appropriate donor limb lengths in bilateral upper limb amputees qualifying for vascularized composite allotransplantation. We hypothesized mathematical equations could be created using long bone length ratios, and applied to radiographs, to approximate the patient’s limb length prior to amputation. Methods: A data set of 30 skeletons’ unilateral upper limb long bones measured using osteometric board and calipers was used. Anatomic segment ratios were calculated based on humerus length after multivariate linear regression analysis. For clinical application testing, 5 cadavers’ upper limbs were radiographed. Radiographic bone lengths were then measured along the long axis of each long bone. These measured radiographic lengths were then compared with the predicted bone lengths, generated from the skeleton data set ratios, for each cadaver. Results: The chi-square goodness-of-fit test showed excellent fit (P < .01) between the predicted and radiographically measured lengths for the 5 cadavers, and interobserver measurements showed no statistical difference. Depending on the cadaver, percent error in total limb length predicted to measure ranged from 0.9% to 2.7%. The variables to multiply an individual humerus length to calculate a given anatomic segment thus proved to be effective. Conclusions: If a bilateral upper limb amputee has 1 intact humerus, ratios to the humerus length can be reliably applied to calculate the preamputation limb length based on the patient’s radiographic humerus length. These formulas are indicated for finding the appropriate limb lengths, and smaller anatomic segments, for donor-recipient matching in upper limb transplantation.

2559: Clinical application of mathematical long bone ratios to calculate appropriate donor limb lengths in bilateral upper limb transplantations

2559: Clinical application ofmathematical long bone ratios to calculate appropriate donor limb lengths in bilateral upper limb transplantations Justyn Lutfy, Alexis Pietak, Shaun D. Mendenhall , and Michael W. Neumeister Southern Illinois University School of Medicine, Carbondale, IL, USA; Tufts University, Boston, MA, USA; The Institute for Plastic Surgery, Carbondale, IL, USA Background Limited methods exist to aid in deciding the appropriate donor limb lengths in bilateral upper limb amputees qualifying for vascularized composite allotransplantation. To aid in this decision, our hypothesis was that mathematical equations could be created using long bone length ratios to approximate the patient’s limb length prior to amputation. Methods A collection of 30 skeletons’ unilateral upper limb long bones were measured using osteometric board and calipers to create a base data set. Anatomic segment ratios were calculated based on humerus length for males and females after multivariate linear regression analysis indicated a statistical difference. For clinical application testing, 5 minimally preserved cadavers underwent standardized upper limb x-rays. Radiographic bone lengths were measured along the long axis of the humerus, forearm, and third ray. These measured radiographic anatomic lengths were then compared to the predicted bone lengths, generated from the skeleton data set ratios, for each cadaver. Results The Chi Square Goodness of Fit test showed excellent fit (p < 0.025 to p < 0.001) between the predicted and radiographically measured lengths for the 5 cadavers. Depending on the cadaver, percent error in total limb length predicted to measured ranged from 0.1% to 5%. Table 1 shows the variables to multiply an individual humerus length to calculate a given anatomic segment. Interobserver measurements showed no statistically significant difference using the Bland-Altman method. Conclusion If a bilateral upper limb amputee has one intact humerus, ratios to the humerus length can be reliably applied to calculate the pre-amputation limb length based on the patient’s radiographic humerus length. These formulas are indicated for finding the appropriate limb lengths, and smaller anatomic segments, for donor-recipient matching in upper limb transplantation.

Abstract 154: the anti-neoplastic effect of aminosterol squalamine on melanoma.

PurPose: Squalamine, a recently discovered aminosterol, has notably been shown to be effective as both an antibiotic and an inhibitor of angiogenesis. This intrinsic anti-angiogenic effect of squalamine has been studied in the literature for its clinical capacity to reduce cancer progression. Here, we suggest an additional role of squalamine in inducing melanoma destruction via induction of apoptosis and or necrosis of melanotic cells through angiogenic inhibition.

Abstract 6: The BREASTrial: Breast Reconstruction Evaluation of Acellular Dermal Matrix as a Sling Trial, Design and Stage I Outcomes of a Randomized Trial.

Methods: A prospective, randomized, placebo-controlled clinical trial was designed to describe the efficacy of injected Btx-A in alleviating pain due to Raynaud’s disease. Our secondary goal was to describe this minimally invasive therapy’s effects and impact on quality-of-life by measuring subjective pain scores, pain-free intervals, ulcer healing, changes in hand function, finger survival, and subsequent treatment choices. Study participants were randomized to receive injection with either placebo (normal saline) or 100 units of Btx-A into the palm around involved digital neurovascular bundles. Data collection included subjective evaluation of pain relief, serial photography of wound healing, and objective data on tissue perfusion using a Doppler perfusion imager and Periscan image analysis software.