[Free flap reconstruction in the head and neck. Indications, technical aspects and outcomes]. / Reconstrucción de cabeza y cuello mediante colgajos libres microvascularizados. Indicaciones, aspectos técnicos y resultados.

INTRODUCTION AND OBJECTIVES: The use of microvascular free flaps (MFF) has become a common method of head and neck reconstruction because of its high success rates and better functional results. We report our experience in reconstructing complex defects with MFF. METHODS: We analysed a series of 246 patients that underwent reconstruction using MFF in our Department from 1991 to 2013. RESULTS: There were 259 interventions performed in 246 patients. The most common reason for surgery was tumour recurrence (46%), followed by primary tumour resection (25%). The hypopharynx (52%) and the craniofacial region (22%) were the most frequently reconstructed sites. The free flaps most commonly used were the radial forearm free flap (41%) and the anterolateral thigh free flap (35%). Overall success and complication rates of 92% and 20% respectively were reported. CONCLUSIONS: The microvascular free flap is a reliable and useful tool for reconstructing complex head and neck defects and continues to be the reconstructive modality of choice for these defects.

Free flaps in orbital exenteration: a safe and effective method for reconstruction.

The aim of this study was to investigate the course of reconstructive treatment and outcomes with use of free flaps after orbital exenteration for malignancy. Charts of patients who had free flap reconstruction after orbital exenteration were retrospectively reviewed and the surgical technique was evaluated. Demographics, histology, surgical management, complications, locoregional control, and survival were analyzed. We performed 22 flaps in 21 patients. Reconstruction was undertaken mainly with anterolateral thigh (56 %), radial forearm (22 %), or parascapular (22 %) free flaps. Complications occurred in 33 % of patients and the flap's success rate was 91 %. The 5-year locoregional control and survival rates were 42 and 37 %, respectively. Free tissue transfer is a reliable, safe, and effective method for repair of defects of the orbit and periorbital structures resulting from oncologic resection. The anterolateral thigh flap is a versatile option to reconstruct the many orbital defects encountered.

A test of Rescorla and Wagner's (1972) prediction of nonlinear effects in contingency learning.

According to most theories, in a simple contingency learning situation, excitatory learning occurs when the probability of the unconditioned stimulus in the presence of the conditioned stimulus (p(1)) is higher than the probability of the unconditioned stimulus in the absence of the conditioned stimulus (p(2)). In Rescorla and Wagner's (1972) model, this prediction varies, depending on the parameters used. In the following experiments, we evaluated whether the difference between p(1) and p(2) that is required to produce excitatory conditioning is the same, independent of the specific value of p(1), or whether this difference varies proportionally to p(1)'s value. To do so, an appetitive procedure of Pavlovian conditioning with rats was used. In four experiments, we compared different levels of contingency (low, medium and high) and found that the difference between p(1) and p(2) that is required to produce excitatory conditioning increases when the value of p(1) is higher. The possibility of analyzing contingency learning as a discrimination between p(1) and p(2) is also discussed.

Use of lateral circumflex femoral artery system free flaps in skull base reconstruction.

We present a 10-year retrospective study at a tertiary center designed to evaluate the advantages, complications, and comparative results using lateral circumflex femoral artery (LCFA) system free flaps for cranial base reconstruction. In this study, a cranial base defect refers to exposed intracranial contents to the skin, paranasal sinuses, nasopharynx, oropharynx, or oral cavity. These defects resulted from resections of primary or recurrent neoplasms or from secondary problems after cranial base surgery. We performed 20 flaps in 20 patients. The selection of flap was as follows: 8 combinations of anterolateral/anteromedial thigh flaps with vastus lateralis muscle or tensor fascia lata flaps, 6 ALT fasciocutaneous flaps, and 6 muscle/myocutaneous flaps. The flap's success rate was 95% (19/20). Early major complications included 1 perioperative death, and there was 1 myocardial infarction. Minor complications included 1 partial (12%) flap loss, 2 temporal cerebrospinal fluid leak, 2 donor-site hematoma, 2 minor wound breakdown, 3 facial nerve weakness, and 4 donor-site numbness. Among 20 patients undergoing LCFA system flap reconstruction, 12 are alive and disease free. Local recurrence occurred in 1 patient. She underwent ablative surgery and a new successful free flap (forearm flap); after 2 years, the patient is disease free. The LCFA system flaps in skull base reconstruction provide versatility in flap design and availability of adequate tissues to fill dead space, and it offers vascularized fascia to augment dural repairs. It also provides a very long pedicle and allows simultaneous flap harvest with low donor-site morbidity.

Refinements in dorsoulnar flap of the thumb: 15 cases.

PURPOSE: We report 2 modifications of the classic Brunelli flap to avoid vascular compromise and first web contracture, common when using medium or large flaps. METHODS: We treated 15 patients with posttraumatic loss of palmar surface and distal amputation of the thumb, with dorsoulnar flap associated with 2 refinements. The first technical tip was an adipofascial extension proximal in the flap aimed to decrease the morbidity of the donor site without changing the potential covering of the flap. The second was always to graft the pedicle of the flap, avoid vascular compression problems, and moreover, to use the pedicle to cover the traumatic area. All ulnar dorsal digital nerves of the flaps were reconnected to one of the volar digital nerves. The minimum patient follow-up was 12 months. RESULTS: All flaps achieved primary healing without major complications. There were no donor site problems. Cosmetic debulking of the flap over the pedicle has not been required. CONCLUSIONS: The Brunelli flap is a good technique to cover small and moderate defects of the thumb, although the drawback of this procedure is the lack of sensory recovery. The refinements of this series can help to improve the use of this flap and avoid complications in the donor site.

Blocking of conditioning of tentacle lowering in the snail (Helix aspersa).

Experiment 1 established the effectiveness of an appetitive conditioning of odours procedure with snails (Helix aspersa) that was subsequently used for the study of blocking. In this important phenomenon, the conditioning of a CS1 (where CS is the conditioned stimulus) prior to conditioning of a compound, CS1CS2, blocked the conditioning to the CS2. Experiments 2a, 2b, and 2c demonstrated this associative effect using three different experimental controls. Experiments 3a and 3b replicated the blocking effect and allowed us to reject an explanation of blocking based on generalized effects of several treatments of diverse stimuli in blocking and control groups (the pseudoblocking effect). The implications of these results for the study of invertebrate cognition by means of conditioning techniques are discussed.