Neural Pedicle Research Articles

Creating and Transferring an Innervated, Vascularized Muscle Flap Made from an Elastic, Cellularized Tissue Construct Developed In Situ.

Reanimating facial structures following paralysis and muscle loss is a surgical objective that would benefit from improved options for harvesting appropriately sized muscle flaps. The objective of this study is to apply electrohydrodynamic processing to generate a cellularized, elastic, biocomposite scaffold that could develop and mature as muscle in a prepared donor site in vivo, and then be transferred as a thin muscle flap with a vascular and neural pedicle. First, an effective extracellular matrix (ECM) gel type is selected for the biocomposite scaffold from three types of ECM combined with poly(ester urethane)urea microfibers and evaluated in rat abdominal wall defects. Next, two types of precursor cells (muscle-derived and adipose-derived) are compared in constructs placed in rat hind limb defects for muscle regeneration capacity. Finally, with a construct made from dermal ECM and muscle-derived stem cells, protoflaps are implanted in one hindlimb for development and then microsurgically transferred as a free flap to the contralateral limb where stimulated muscle function is confirmed. This construct generation and in vivo incubation procedure may allow the generation of small-scale muscle flaps appropriate for transfer to the face, offering a new strategy for facial reanimation.

Chimeric Latissimus Dorsi Flap in One-Stage Reconstruction of Depressor Muscle Dysfunction and Depression Deformity in the Perimandibular Area.

Depression deformity and paralysis of depressor muscles (DMs) may occur following tumor resection in the perimandibular region. Obtaining satisfactory results is challenging. The authors report 3 cases of 1-stage reconstruction by transferring neurovascular chimeric latissimus dorsi (LD) musculo-adipose flaps, with satisfactory results. Three patients with depression deformity and DMs dysfunction after tumor resection in the perimandibular region underwent chimeric LD flap transfer. The flap comprised 1 portion with adipose tissue for augmentation, and the other contained muscle bellies with 1 or 2 neural pedicle (s) for DM reanimation. In case 1, the neural pedicle was sutured to the contralateral marginal mandibular branch. In case 2, the neural pedicle was sutured to the ipsilateral marginal mandibular branch. In case 3, the neural pedicle was sutured to both branches of the facial nerve. All patients were satisfied with the deformity corrections. However, contractions of the transferred muscles varied. Case 1 showed insufficient contraction. Case 2 had excessive muscle contraction. In case 3, the muscle had double innervation, and well-balanced contraction was maintained for 3 years. Neurovascular chimeric LD flaps are versatile and useful for secondary reconstruction after tumor resection for functional loss of mimetic muscles. The ipsilateral facial nerve may be an effective motor source.

An Anatomical Study of the Length of the Neural Pedicle after the Bifurcation of the Thoracodorsal Nerve

ABSTRACTBackground: Latissimus dorsi muscle is considered as a key stone most important muscle in plastic surgery used for many reconstructive surgical procedures varying from facial reanimation and breast reconstruction to lower limb reconstruction. it is essential to have knowledge about The branching pattern and length of the thoracodorsal nerve which is the nerve supply of this precious latissimus dorsi distal to the splitting of this nerve. For innervated functional muscle transplant procedures, the length of nerve pedicles available for nerve anastomosis is crucialAim of the Work: Is to investigate the topography and branching pattern of the thoracodorsal and also measure its length distal to its splitting.Materials and Methods: Sixteen latissimus dorsi muscles were dissected in eight adult embalmed human specimens in Anatomy department Faculty of medicine Alexandria university. The thoracodorsal neurovascular bundle was dissected and the pattern of branching of the thoracodorsal nerve was identified The branches were dissected up to the latissimus dorsi muscle and further intramuscularly. All lengths were measured using a vernier caliber. Surgically, in total, 10 patients with recurrent squamous cell carcinoma were undergone surgery permitting simultaneous cancer resection and harvesting of latissimus dorsi flap in Plastic surgery department, Faculty of medicine, Menufia University, Informed written individual consent was obtained for all the patients.Results: The median length of the medial branch was 3.45 cm (range, 1.80 to 5.5 cm; mean, 3.60 cm; SD, 1.04 cm). As regard the branching pattern of the thoracodorsal nerve distal to its splitting it varied from three branches pattern in 75%, two branches pattern in 23% of the specimens and in one case continued as one branch on the lateral border of latissimus dorsi muscle In one other specimen thoracodorsal nerve distal to its split gave many branches and in this specimen abreast mass was noticed on the corresponding side of this thoraco dorsal nerve. The veins and arteries showed a similar pattern, with a median length that is similar to that of the thoracodorsal nerve.The median length of the middle branch was3.50 cm (range, 2.4 5 to 4.65 cm; mean3.45 cm; SD, 0.88 cm), The lateral branch showed a median length of 3.99 cm (range, 2.5 5 to 5.95 cm; mean, 3.85 cm; SD, 0.95 cm). The mean length of the thoracodorsal nerve measured from the posterior root to the split was 12.5 cm.Surgically, by surface area the latissimus dorsi is the largest muscle in the body. It can be as large as 20 x 40cms, enabling latissimus dorsi flaps to cover very large defects after resection of squamous cell carcinoma in head and neck region especially in temporal and scalp regions.Conclusions: The separate neurovascular branches and its minimal pedicle length make the latissimus dorsi muscle very suitable for single functional free muscle transfer, using only the lateral part of the latissimus dorsi muscle, and double functional free muscle transfer using only one vascular pedicle. This suggests the possibility of a multiple, segmentally innervated latissimus dorsi muscle transfer. And actually this is facilitated by this branching pattern of the thoracodorsal nerve.There may be association between the multiple branch pattern of the thoracodorsal nerve and presence of breast mass, an issue which need more research. From surgical points of view, there is strong need for preoperative diagnostic tools to predict the pattern of branching of neuro vascular bundle of latissimus muscle, to help preoperative planning especially in cases as facial reanimation, also in cases that we need more than one muscular functional units, also in cases that we might need to leave portion of muscle for better esthetics and better function of limb movements.

Modes of ontogenetic allometric shifts in crocodylian vertebrae

During postnatal ontogeny of vertebrates, allometric trends in certain morphological units or dimensions can shift drastically among isometry, positive allometry, and negative allometry. However, detailed patterns of allometric transitions in certain timings have not been explored well. Identifying the presence and nature of allometric shifts is essential for understanding the patterns of changes in relative size and shape and the proximal factors that are controlling these changes mechanistically. Allometric trends in 10 selected vertebrae (cervical 2–caudal 2) from hatchlings to very mature individuals of Alligator mississippiensis (Archosauria, Crocodylia) are reported in the present study. Allometric coefficients in 12 vertebral dimensions are calculated and compared relative to total body length, including centrum, neural spine, transverse process, zygapophysis, and neural pedicle. During the postnatal growth, positive allometry is the most common type of relative change (10 of the 12 dimensions), although the diameter of the neural canal shows a negative allometric trend. However, when using spurious breaks (i.e. allometric trends subdivided into growth stages using certain growth events, and key body sizes and/or ages), vertebral parts exhibit various pathways of allometric shifts. Based on allometric trends in three spurious breaks, separated by the end of endochondral ossification (body length: approximnately 0.9 m), sexual maturity (1.8 m), and the stoppage of body size increase (2.8 m), six types of ontogenetic allometric shifts are established. Allometric shifts exhibit a wide range from positive allometry restricted only in the early postnatal stage (Type I) to life-long positive allometry (Type VI). This model of ontogenetic allometric shifts is then applied to interpret potential mechanisms (causes) of allometric changes, such as (1) growth itself (when allometric trend gradually decreases to isometric or negative allometric change: Type II–IV allometric shift); (2) developmental constraint (when positive allometry is limited only in the early growth stage: Type I allometric shift); and (3) functional or biomechanical drive (when positive allometry continues throughout ontogeny: Type VI allometric shift).

Applied anatomical study of the gracilis muscle flap for tongue reconstruction

To study the anatomic features of the gracilis muscle flap and its clinical application in tongue reconstruction. Thirty gracilis muscles in 15 cadavers were dissected, and the morphometric parameter of the gracilis muscle and the origin, length, diameter of the vascular and nerve pedicle were observed and measured. The length of the total gracilis and the muscle belly was 41.8±3.9 cm and 31.0±3.6 cm respectively, and the width and thickness of the muscle was 3.2±0.7 cm and 1.7±0.2 cm respectively. The blood supply to the gracilis originated from multiple source vessles, and two to five pedicles supplied the gracilis from its deep surface and entered the muscle near its anterior border, of which the dominant pedicle and the first distal pedicle were consistent in their anatomy which originated from the profunda femoris vessels and the femoris vessels respectively. The length and external diameter of these vessels were suitable for microvascular anastomosis, while other vessel pedicles were neither consistent in their anatomy nor the length and external diamiter suitable for microvascular anastomosis. The nerve to the gracilis arose from the anterior division of the obturator nerve consistently and its length and external diameter was suitable for anastomosis with the hypoglossal nerve. Because of superficial location, excellent morphological match for tongue, consistency in its vascular and neural pedicle's anatomy and suitability of neurovascular pedicle's length and external diameter for microsurgical anastomoses, possibility of regaining tongue movements, the gracilis flap is a ideal option for tongue reconstruction.

Cross-Face Neurotized Platysmal Muscular Graft for Upper Eyelid Reanimation

Upper eyelid reanimation is one of the most important aspects of facial paralysis. The ideal method would be one that provided dynamic restoration of voluntary eye closure, involuntary blinking, and corneal reflex. Innervation to the platysma has shown to be relatively consistent, which would allow its use as a muscle graft neurotized by the contralateral healthy facial nerve for eyelid reanimation. Six fresh cadavers, 12 sides, were studied by dissecting the main trunk of the facial nerve and its cervicofacial division. Special attention was paid at the emergence of cervical branches to the platysma and its distribution on the undersurface of the muscle as well as its relationships with regional anatomic references. One major branch with 1 or 2 accessory branches was found to emerge from the cervicofacial division, 1.5 cm distal to its origin in the facial nerve trunk. The major branch showed an oblique course, starting approximately 1 cm below the angle of the mandible and coursing toward the inferomedial border of the muscle. Harvest of a 3 × 2 muscle piece with a 10-cm-long neural pedicle was possible in all specimens. When presented over the superior eyelid, the nerve branch was found to reach the contralateral frontal branch of the facial nerve. Innervation to the platysma muscle is relatively constant and consists of 1 major branch accompanied by 1 or 2 accessory branches. Harvest of a muscle flap with a neural pedicle long enough to reach the contralateral healthy side is anatomically feasible.

Neuroanatomy of Extensor Digitorum Brevis Muscle for Reanimation of Facial Paralysis

This study explores the vascular and morphologic anatomy of extensor digitorum brevis (EDB), which can be alternatives to donor muscles used in functional muscle transfer in long-standing facial paralysis reanimation. A total of 14 EDB muscles from 7 embalmed cadavers were dissected and examined. Diameters and lengths of major and minor arteries supplying the muscle, venous pedicle diameter, neural pedicle diameter and length, their entrances into the muscle, the extendibility of neurovascular pedicles, when necessary, and the morphology of muscles were evaluated. Mean results obtained for EDB muscle in the study were as follows: the longest distance between the starting point and the area where the tendon started was a mean of 5.1 ± 0.1 cm (range, 4.8-5.4 cm), the distance between the widest points was 4.2 ± 0.3 cm (range, 3.7-4.9 cm), the thickest area was 1.4 ± 0.8 cm (range, 1-1.9 cm), and surface area was a mean of 32.1 ± 1.2 cm (range, 29.8-35.7 cm). The mean length of the major artery is type 2 according to Mahtnes-Nahai classification and was found to be 2.1 ± 0.03 cm (range, 1.6-3.2 cm), and its diameter was found to be 1.95 ± 0.15 mm (range, 1.7-2.1 mm). Mean length and diameter of the nerve providing motor innervation to the muscle were found to be 2.3 ± 0.03 cm (range, 2.1-2.6 cm) and 2.4 ± 0.08 mm (range, 2-2.9 mm), respectively. As a result of this preliminary study, we think that the morphologic and neurovascular structures of this muscle are suitable for use in long-standing facial paralysis reanimation.

An Anatomical Study of the Length of the Neural Pedicle after the Bifurcation of the Thoracodorsal Nerve: Implications for Innervated Free Partial Latissimus Dorsi Flaps

For innervated functional muscle transplant procedures, it is essential to have knowledge about the length of nerve pedicles available for nerve anastomosis. For the latissimus dorsi muscle, the thoracodorsal nerve divides into two funicles that separately innervate the medial and lateral portions of the muscle. This suggests the possibility of a multiple, segmentally innervated latissimus dorsi muscle transfer. The branching and length of the thoracodorsal nerve distal to the bifurcation have not been described. This surgical-anatomical study presents anatomical data on these practical/clinical issues. Eleven latissimus dorsi muscles were dissected in eight adult embalmed human specimens. The thoracodorsal neurovascular bundle was dissected from insertion to proximal of the bifurcation. Measurements were taken indirectly from standardized photographic images and analyzed with ImageJ and standard spreadsheet software. The mean age of the specimens was 66 years. The median pedicle length of the lateral part of the muscle was 3.8 cm (range, 2.41 to 5.93 cm). The median length of the medial branch was 3.49 cm (range, 1.7 to 5.12 cm). Proximal branching of the medial pedicle of the bifurcation was identified in approximately two-thirds of the specimens and had a median of 3.55 cm (range, 2.54 to 4.68 cm). The veins and arteries showed a similar pattern, with a median length slightly less than that of the thoracodorsal nerve. The separate neurovascular branches and its minimal pedicle length make the latissimus dorsi muscle very suitable for single functional free muscle transfer, using only the lateral part of the latissimus dorsi muscle, and double functional free muscle transfer using only one vascular pedicle.

A pedicled muscle flap based solely on a neural pedicle

We tested the hypothesis that the intrinsic vascular plexus of the motor nerve could support viability in a rat hindlimb muscle flap. In a preliminary study, we examined the course and vascularity of the sciatic nerve, the peroneal nerve, and the peroneous longus muscle in the rat hindlimb via anatomic dissection, microangiography, and histologic study (n = 10 animals). On the basis of this examination, the peroneous longus muscle was chosen as our experimental model in this study. In 12 animals, the peroneus longus was acutely elevated, which severed all tendinous and vascular structures, this left the muscle pedicled on the motor nerve only (Group I). Animals in Group II underwent a staged elevation of the flap with division of the vascular pedicle, the tendon of insertion, and the tendon of origin during separate procedures that were 5 days apart (n = 12). Muscle viability was evaluated by gross inspection, measurement of muscle weight and length, nitroblue tetrazlium (NBT) staining, microangiography, and histology. NBT staining demonstrated that immediate elevation of the peroneus longus muscle flaps led to an average necrotic area of 80.6% +/- 9.8% (Group I). A significant improvement in viability was observed for muscle flaps of animals in Group II, with peroneus longus muscle necrosis averaging 25.6% +/- 9.3%. Microangiography demonstrated that the intrinsic vascularity of nerve was increased dramatically in Group II. These data support the hypothesis that the intrinsic vascular plexus of the motor nerve of a skeletal muscle can support at least partial viability of a muscle flap. However, this vascular axis is inadequate to support complete viability of a muscle flap if the flap is elevated immediately. If a staged elevation affects a surgical delay, the viability of a muscle flap elevated on a neural pedicle can be increased significantly. With adjustments in the delay procedure, this strategy may allow transfer of muscle flaps when maintenance or reconstitution of the primary vascular axis is not possible.

Evaluation of Facial Allograft Transplantation in Humans in a Cadaver

Evaluation of Facial Allograft Transplantation in Humans in a Cadaver

A surgical approach to chronic aortomyoplasty in the goat model.

The left latissimus dorsi skeletal muscle of seven male goats was prepared and applied circumferentially to the descending aorta just below the subclavian artery. Stimulation of the neural pedicle of the latissimus dorsi was performed in an attempt to convert it to a fatigue-resistant cardiac-like muscle. Timing of the stimulus was in diastole. Biochemical assays established the conversion, and echocardiography demonstrated aortic compressions in the area of the muscle wrap. Although limited in numbers, the converted latissimus dorsi muscle in the extra-aortic position appears to provide diastolic augmentation.

The Weberian Apparatus of Hybognathus placitus and H. nuchalis (Cyprinidae)

The Weberian apparatus of Hybognathus placitus is described and compared with that of H. nuchalis. Although considerable variation in the Weberian components was observed, the many differences indicate that full specific rank should be retained for both Hybognathus placitus and H. nuchalis. The lateral proc- esses of the first and second vertebrae are regarded as modified ventral ribs. The ascending processes of the scaphium and intercalarium are believed to be homologous to postzygapophyses. The pit into which the articulating process of the scaphium fits is regarded as homologous to those accommodating the third neural pedicle and fourth neural arch. The neural complex is probably composed of the third neural spine plus interspinous bones. The os suspensorium is part of the fourth pleural rib. The most conspicuous difference between these species involves the shape of the pharyngeal process of the basioccipital and the muscles inserted on it. Hybognathus placitus Girard and Hybognathus nuchalis Agassiz present some taxonomic difficulty, but have long been regarded as dis- tinct species. Bailey (1956) concluded that environmental variations, at the time of early development, are translated into structural dif- ferences that can be perceived throughout the life of the fish. He con- sidered both H. Nuchalis and H. placitus as phenotypes of H. nuchalis. The purpose of this study was to test this hypothesis, using the mor- phology of the Weberian apparatus. The Weberian apparatus was named in honor of the discoverer, E. J. Weber, by Bridge and Haddon (1889). Since Weber used nomencla- ture as applied to the ossicles of the mammalian middle ear, not homol- ogous with those of fishes, Bridge and Haddon proposed the nomen- clature currently used. Readers interested in the literature pertinent to the morphology and embryonic development of the Weberian ap- paratus should consult the works of Evans (1924-1925), Watson, (1939), Krumholz (1943), Nelson (1948), 1949, 1955), and Butler (1960). Materials for this study were from a large part of the ranges of the two species, from the Rio Grande to the Missouri River Basin in South Dakota and Montana. We are indebted to Dr. R. M. Bailey, of the 1 Contribution from the Research Foundation and No. 344 from the Zoology De- partment, Oklahoma State University, with partial support from the National Science Foundation.