Use of pectoralis minor muscle in immediate reconstruction of the breast

A technique is described in which the pectoralis minor muscle is rotated as a muscle pedicle flap to be used in immediate reconstruction of the breast. The advantages of this procedure are that it provides additional muscle coverage over the prosthesis as well as preventing lateral displacement. Seven patients have undergone this technique with excellent results.     

Connection of the ligamentum coracoglenoidale with the muscular pectoralis minor

The ligamentum coracoglenoidale and its connection with the m. pectoralis minor are described. We have found three different shapes of this ligament. In 47% of the dissected specimens it was a strong round ligament, and in 39% it was a membraneous ligament that always inserted above the lig. coracohumerale. In 14%, separation of the lig. coracoglenoidale from the lig. coracohumerale at the coracoidal insertion was either impossible at all or only feasible by sharp dissection. In 16% we found a bundle of fibres of the m. pectoralis minor running over the processus coracoideus towards the head of the scapula. In two instances this bundle inserted at the humeral head. Possibly, there is a similar function as that of the meniscotibial and the meniscofemoral ligaments of the knee joint. A connection with the 'impingement syndrome' of the shoulder joint will be the base of further investigations.     

Arterial and venous anatomical features of the pectoralis minor muscle flap pedicle

The pectoralis minor muscle has been used as an innervated, vascularized, free-muscle graft in the field of facial reanimation for 20 years. Throughout this period, several centers have demonstrated consistent success with functional muscle transfer; however, opinions regarding the arterial pedicle of the flap have varied. The lateral thoracic and thoracoacromial arteries have been proposed as the predominant arterial sources. It has been the experience of our unit that a vessel (not described in anatomy textbooks) arising directly from the axillary artery and entering the muscle from its dorsal surface provides the dominant supply to the flap and is capable of sustaining it for free-tissue transfer. The vascular pedicle encountered was recorded and photographed in 97 consecutive cases in which the pectoralis minor muscle flap was raised. The findings demonstrated that the dominant supply to the muscle was from a single artery in 77 percent of cases and took the form of an artery arising directly from the axillary vessel in 72 percent of cases. More than one major arterial source was noted in the remainder of the cases. The venous outflow was usually through single or multiple veins running directly from the muscle into the axillary vein.     

The nerve supply to the clavicular part of the pectoralis major muscle: an anatomical study and clinical application of the function-preserving pectoralis major island flap

The purpose of this study was to investigate the nerve supply to the clavicular part of the pectoralis major muscle so that the innervation to this part can be maintained in the muscle-preserving pectoralis major island-flap transfer. Although methods have been described that include a limited portion of the muscle while leaving the upper parts undisturbed with an intact motor innervation, reports on anatomical studies of this nerve supply are brief. The distal distribution of the nerves, the spatial relationship to the main vascular pedicle, and the ways to preserve them during surgical procedures remain unclear. Surgically relevant features of the clavicular part of the pectoralis major muscle were studied by dissection. The nerve supply to this part was examined on 11 sides of eight formalin-fixed cadavers. Two fresh cadavers were used for dissection, intraarterial polymer injection, and application of a nerve-preserving surgical technique. In all subjects, a separate nerve innervated the clavicular and upper medial sternocostal portions of the pectoralis major muscle. This nerve arises craniomedial to the main vascular pedicle of the flap and divides into several branches. These branches run in a fascia on the deep surface of the pectoralis major muscle, superficial to the origin and distal course of the vascular pedicle. Most branches to the clavicular part end medial to the coracoid process. The course of the branches to the upper sternocostal part is more medial. Based on their anatomical findings, the authors propose a surgical technique for transfer of the pectoralis major island flap to the head and neck area through a tunnel in the deltopectoral groove, lateral to the origin of the vascular pedicle. Head and neck reconstruction was performed using this technique. The presented method is a muscle-preserving procedure that maintains maximal donor-site function and morphology.     

The pectoralis minor vascularized muscle graft for the treatment of unilateral facial palsy

A series of 10 pectoralis minor vascularized muscle transfers to reanimate the face in unilateral facial palsy are presented. The procedure is carried out in two stages. The first stage constitutes a nerve graft from the functional contralateral facial nerve to the preauricular region of the paralyzed side. Six months later, the pectoralis minor is transferred to the denervated side of the face with restoration of its neurovascular pedicle. The muscle is well suited to its new position with respect to length and bulk, as well as its fanlike shape. The diameter of its vascular pedicle is comparable with the facial vessels. The results demonstrate function in 8 of the 10 grafts, the two failures relating to early vascular thrombosis rather than an inability to reinnervate the muscle grafts.     

The extended pectoralis major myocutaneous flap: uses and indications

The vascular territory of the pectoralis major muscle and overlying skin was studied by selective intraarterial dye injections in fresh cadavers. The area of skin overlying the anterior chest and abdominal wall beyond the limits of the pectoralis major muscle that can be elevated as an extended myocutaneous flap was determined. The cadaver injections were evaluated to determine the size and shape of the skin island used to reconstruct defects of the head, neck, and upper trunk with an extended skin paddle off the pectoralis major muscle. Pectoralis muscle flaps with variously shaped skin paddles, some extending beyond the limits of the muscle, were used in 27 patients to cover large soft-tissue defects of the upper thorax, face, and floor of the mouth and as a skin tube to reconstruct the cervical esophagus. The size of the skin paddle ranged from 5 x 7 cm to 26 x 16 cm. All flaps survived completely, and there were no major donor-site complications.     

Inspiratory and expiratory patterns of the pectoralis major muscle during pulmonary defensive reflexes

Experiments wereconducted to determine the discharge pattern of the pectoralis majormuscle during pulmonary defensive reflexes in anesthetized cats(n = 15). Coughs andexpiration reflexes were elicited by mechanical stimulation of theintrathoracic trachea or larynx. Augmented breaths occurredspontaneously or were evoked by the same mechanical stimuli.Electromyograms (EMGs) were recorded from the diaphragm, rectusabdominis, and pectoralis major muscles. During augmented breaths, thepectoralis major had inspiratory EMG activity similar to that of thediaphragm, but during expiration reflexes the pectoralis major also hadpurely expiratory EMG activity similar to the rectus abdominis. Duringtracheobronchial cough, the pectoralis major had an inspiratory patternsimilar to that of the diaphragm in 10 animals, an expiratory patternsimilar to that of the rectus abdominis in 3 animals, and a biphasicpattern in 2 animals. The pectoralis major was active during both the inspiratory and expiratory phases during laryngeal cough. We conclude that, in contrast to the diaphragm or rectus abdominis muscles, thepectoralis major is active during both inspiratory and expiratory pulmonary defensive reflexes.

     

The functional pectoralis major musculocutaneous island flap in head and neck reconstruction

We describe our experience with the true island pectoralis major musculocutaneous flap in patients with high-volume defects for whom free-tissue transfer is unsuitable. Our operative technique is presented. We have modified the method of making a true island of the pectoralis major musculocutaneous flap on a muscle-free pedicle as first described by Wei et al. in 1984. This maintains maximal donor-site muscle function and facilitates closure of the donor-site defect. We present our results in 24 patients, in whom the flap has proved to be robust and reliable. The flap's advantages in terms of increased pedicle length, wider arc of rotation, decreased pedicle bulk, and improved cosmesis of the reconstruction are discussed.