Prevalence and Utilization of Obturator Artery Anatomic Variant in Autologous Breast Reconstruction.

BACKGROUND: The objective of this study is to quantify the prevalence and describe the utilization of an anatomic vascular variant in which the obturator artery (OA) arises from the trunk of the deep inferior epigastric artery (DIEA) in stacked/dual-pedicled autologous breast reconstruction. When this variant is identified preoperatively on computed tomography angiography (CTA), it may be utilized in a "flow-through" fashion to direct antegrade internal mammary artery (IMA) flow into a second free flap to facilitate anastomotic arrangement and optimize perfusion. METHODS: Preoperatively obtained abdomen/pelvis CTA imaging of 121 autologous breast reconstruction patients were retrospectively reviewed for the unilateral or bilateral presence of the OA branch arising from the DIEA (OA variant). The results were analyzed using descriptive statistics. RESULTS: Our analysis revealed the presence of the OA variant in 60 of the 121 (49.6%) breast reconstruction candidates, either unilaterally or bilaterally. Out of these patients, the variant was present unilaterally in 33 (55%) and bilaterally in 27 (45%) patients. Of the unilateral variants, 12 (36.4%) patients demonstrated right-sided laterality, while 21 (63.6%) patients demonstrated left-sided laterality. Clinically, this anatomic variant has been utilized in several cases of autologous breast reconstruction with flap survival in all cases. CONCLUSION: Utilization of this anatomic variant in stacked or dual-pedicled autologous breast reconstruction results in antegrade IMA perfusion of both primary and secondary flaps, as well as improved size match compared with other anastomotic options. Knowledge of the vascular anatomy and variations in the inferior epigastric system is crucial to both preventing complications and optimizing flap planning and outcome.

A Description of the Vascular Anatomy of the Tensor Fascia Lata Perforator Flap Using Computed Tomography Angiography.

BACKGROUND: The perforator anatomy of the tensor fascia lata (TFL) flap has been studied using cadaver dissection; however, exact descriptions of location, size, and origin of perforator vessels using preoperative imaging modalities remain limited. The aims of this study are to describe TFL perforator anatomy using high-resolution computed tomography angiography (CTA) and to correlate these findings with landmarks for the anterolateral thigh flap to facilitate flap planning. METHODS: We identified 33 patients who previously underwent bilateral lower extremity CTAs for preoperative planning of free-flap reconstruction. The images were retrospectively reviewed, and the TFL perforator number, size, type, location, and overall pedicle origin and length were recorded. RESULTS: Thirty-three patients and 59 thighs were included in the study. There was an average of 2.5 perforators per TFL. All perforators arose from the ascending branch of the lateral circumflex femoral artery with an average pedicle length of 8.3 cm (range, 6.0-11.2 cm). Sixty-six percent of perforators were septocutaneous and 34% were musculocutaneous. The average perforator size as measured on CTA was 3 mm. The average perforator location was 10.1 cm inferior and 8.5 cm lateral to the line drawn from the anterior superior iliac spine to the superolateral patella. CONCLUSIONS: To our knowledge, this is the first study to characterize the vascular anatomy of the TFL perforator flap using high-resolution CTA and correlate this with well-established landmarks used in the planning for other thigh-based flaps. We believe data will facilitate flap design and dissection; potentially shortening operating room times, limiting exploratory incisions used to confirm the presence of thigh based perforators, and improving overall outcomes for patients.

Current Techniques for Postoperative Monitoring of Microvascular Free Flaps.

Free tissue transfer (FTT) is used in patients with complicated reconstructive needs; it can provide stable wound coverage, improved aesthetic appearance, and restore functional deficits. Despite the high success rates of free flaps, vascular occlusion is a significant risk leading to flap failure. Many studies have demonstrated that the salvage rate for flaps is inversely related to the time between onset of a vascular problem and its surgical correction. As a result, ongoing postoperative monitoring of free flaps for adequate perfusion is imperative to allow timely and accurate diagnosis of vascular compromise. Close monitoring and prompt notification of the physician if vascular compromise occurs are typically undertaken by first-line nurses. We conducted an integrative literature to identify and evaluate commonly used techniques for monitoring vascular free flaps during the postoperative period. We searched PubMed and Science Direct electronic databases, using the key words: "free-flap" and "monitoring." This article discusses commonly monitoring modalities, along with their advantages and limitations. Whereas large academic institutions may have an experienced nursing staff specifically trained in effective methods for monitoring free flap patients, this situation may not exist in all hospitals where free flap surgeries are performed. We describe techniques that allow easy and timely detection of flap compromise by nursing staff while reducing interuser variability.

Reverse end-to-side nerve transfer: from animal model to clinical use.

PURPOSE: Functional recovery after peripheral nerve injury is predominantly influenced by time to reinnervation and number of regenerated motor axons. For nerve injuries in which incomplete regeneration is anticipated, a reverse end-to-side (RETS) nerve transfer might be useful to augment the regenerating nerve with additional axons and to more quickly reinnervate target muscle. This study evaluates the ability of peripheral nerve axons to regenerate across an RETS nerve transfer. We present a case report demonstrating its potential clinical applicability. METHODS: Thirty-six Lewis rats were randomized into 3 groups. In group 1 (negative control), the tibial nerve was transected and prevented from regenerating. In group 2 (positive control), the tibial and peroneal nerves were transected, and an end-to-end (ETE) nerve transfer was performed. In group 3 (experimental model), the tibial nerve and peroneal nerves were transected, and an RETS nerve transfer was performed between the proximal end of the peroneal nerve and the side of the denervated distal tibial stump. Nerve histomorphometry and perfused muscle mass were evaluated. Six Thy1-GFP transgenic Sprague Dawley rats, expressing green fluorescent protein in their neural tissues, also had the RETS procedure for evaluation with confocal microscopy. RESULTS: Nerve histomorphometry showed little to no regeneration in chronic denervation animals but statistically similar regeneration in ETE and RETS animals at 5 and 10 weeks. Muscle mass preservation was similar between ETE and RETS groups by 10 weeks and significantly better than negative controls at both time points. Nerve regeneration was robust across the RETS coaptation of Thy1-GFP rats by 5 weeks. CONCLUSIONS: Axonal regeneration occurs across an RETS coaptation. An RETS nerve transfer might augment motor recovery when less-than-optimal recovery is otherwise anticipated. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic I.

Effect of cold nerve allograft preservation on antigen presentation and rejection.

OBJECT: Nerve allotransplantation provides a temporary scaffold for host nerve regeneration and allows for the reconstruction of significant segmental nerve injuries. The need for systemic immunosuppression, however, limits the current clinical utilization of nerve allografts, although this need is reduced by the practice of cold nerve allograft preservation. Activation of T cells in response to alloantigen presentation occurs in the context of donor antigen presenting cells (direct pathway) or host antigen-presenting cells (indirect pathway). The relative role of each pathway in eliciting an alloimmune response and its potential for rejection of the nerve allograft model has not previously been investigated. The objective of this investigation was to study the effect of progressive periods of cold nerve allograft preservation on antigen presentation and the alloimmune response. METHODS: The authors used wild type C57Bl/6 (B6), BALB/c, and major histocompatibility Class II-deficient (MHC-/-) C57Bl/6 mice as both nerve allograft recipients and donors. A nonvascularized nerve allograft was used to reconstruct a 1-cm sciatic nerve gap. Progressive cold preservation of donor nerve allografts was used. Quantitative assessment was made after 3 weeks using nerve histomorphometry. RESULTS: The donor-recipient combination lacking a functional direct pathway (BALB/c host with MHC-/- graft) rejected nerve allografts as vigorously as wild-type animals. Without an intact indirect pathway (MHC-/- host with BALB/c graft), axonal regeneration was improved (p < 0.052). One week of cold allograft preservation did not improve regeneration to any significant degree in any of the donor-recipient combinations. Four weeks of cold preservation did improve regeneration significantly (p < 0.05) for all combinations compared with wild-type animals without pretreatment. However, only in the presence of an intact indirect pathway (no direct pathway) did 4 weeks of cold preservation improve regeneration significantly compared with 1 week and no preservation in the same donor-recipient combination. CONCLUSIONS: The indirect pathway may be the predominant route of antigen presentation in the unmodified host response to the nerve allograft. Prolonged duration of cold nerve allograft preservation is required to significantly attenuate the rejection response. Cold preservation for 4 weeks improves nerve regeneration with a significant effect on indirect allorecognition.

Costimulation blockade inhibits the indirect pathway of allorecognition in nerve allograft rejection.

Nerve allografts provide a temporary scaffold for host nerve regeneration. The need for systemic immunosuppression limits clinical application. Characterization of the immunological mechanisms that induce immune hyporesponsiveness may provide a basis for optimizing immunomodulating regimens. We utilized wild-type and MHC class II-deficient mice, as both recipients and donors. Host treatment consisted of triple costimulatory blockade. Quantitative assessment was made at 3 weeks using nerve histomorphometry, and muscle testing was performed on a subset of animals at 7 weeks. Nerve allograft rejection occurred as long as either the direct or indirect pathways were functional. Indirect antigen presentation appeared to be more important. Nerve allograft rejection occurs in the absence of a normal direct or indirect immune response but may be more dependent on indirect allorecognition. The indirect pathway is required to induce costimulatory blockade immune hyporesponsiveness.

Glomus tumor of the index finger.

A 41-year-old female patient presented with localized worsening subungual pain of her right index finger. Subsequent diagnostic evaluation revealed the presence of a glomus tumor. A glomus tumor is a rare tumor with a predilection for the hand. Classic symptoms include pain, pain with pressure, and pain with cold temperature. We present a completely updated literature review that addresses the epidemiology, pathology, presentation, diagnostic evaluation, classification, histology, genetics, and treatment options for glomus tumors.