The dorsal scapular island flap: an alternative for head,neck, and chest reconstruction

The back has become an increasingly popular donor site for flaps because it can provide thin, pliable tissue, with minimal bulk, and the scar can be easily hidden under clothing. The authors performed a cadaveric and clinical study to evaluate the anatomy of the dorsal scapular vessels and their vascular contribution to the skin, fascia, and muscles of the back. On the basis of anatomical studies in 28 cadavers and clinical experience with 32 cases, it was concluded that the dorsal scapular vessels provide a reliable blood supply to the skin of the medial back, making it a versatile flap to use as an island flap. A flap raised on the dorsal scapular vessels can be harvested with a long pedicle and can be rotated to reach as far as the anterior regions of the head, neck, and chest wall. Delaying and expanding the flap may help to facilitate venous drainage. The authors recommend the use of this versatile island pedicle flap as an alternative to microvascular free-tissue transfer for the reconstruction of defects in the head, neck, and anterior chest.     

Use of thirty latissimus dorsi flaps

Experiences with 30 latissimus dorsi flaps are described. Used either as a muscle flap, as a myocutaneous flap, or as an "island" of skin nourished by a subcutaneous pedicle of muscle and vessels, the flap has an excellent blood supply and is suitable for many repairs of defects of the chest wall.     

Shoulder defect correction with the island latissimus dorsi flap

Reconstruction of normal shoulder contour is possible utilizing a latissimus dorsi musculocutaneous flap at the end of a long neurovascular pedicle. The thoracodorsal vessels and their lateral divisions form the basis of the pedicle. The nerve in the pedicle is left intact if maintenance of muscle bulk is desired and sectioned if atrophy is preferred. The amount of muscle taken in conjunction with the skin island is determined by the nature of the defect to be corrected. The twin goals of a single-stage reconstruction and a satisfactory aesthetic result are achieved with this method.     

Finite Element Analysis of Minimal Invasive Transforaminal Lumbar Interbody Fusion

The purpose of our study is to develop and validate three-dimensional finite element models of transforaminal lumbar interbody fusion, and explore the most appropriate method of fixation and fusion by comparing biomechanical characteristics of different fixation method. We developed four fusion models: bilateral pedicle screws fixation with a single cage insertion model (A), bilateral pedicle screws fixation with two cages insertion model (B), unilateral pedicle screws fixation with a single cage insertion model (C), and unilateral pedicle screws fixation with two cages insertion model (D); the models were subjected to different forces including anterior bending, posterior extension, left bending, right bending, rotation, and axial compressive. The von Mises stress of the fusion segments on the pedicle screw and cages was recorded. Angular variation and stress of pedicle screw and cage were compared. There were differences of Von Mises peak stress among four models, but were within the range of maximum force. The angular variation in A, B, C, and D decreased significantly compared with normal. There was no significant difference of angular variation between A and B, and C and D. Bilateral pedicle screws fixation had more superior biomechanics than unilateral pedicle screws fixation. In conclusion, the lumbar interbody fusion models were established using varying fixation methods, and the results verified that unilateral pedicle screws fixation with a single cage could meet the stability demand in minimal invasive transforaminal interbody fusion.     

Multi-scale finite element modelling at the posterior lumbar vertebra: analysis of pedicle stresses due to pars fracture

Multi-scale finite element (FE) model is a cost-effective way to analyse stress response of micro-level structures to the changes in loading at macro-level. This study deals with the development of a multi-scale model of a human vertebra and stress changes in the pedicle at high resolution after a gross fracture at the posterior neural arch. Spondylolysis (pars fracture) is a painful condition occurring in the vertebral neural arch and common especially among the athletic young population. The fracture of the pars significantly alters load distribution and load transfer characteristics at the neural arch. Structural changes in the posterior vertebra due to the new loading patterns can trigger secondary complications. Clinical reports have shown the association of pedicle hypertrophy or pedicle fracture with unilateral pars fractures. However, the biomechanical consequences of pars fracture and its effect on the pedicle have never been studied in detail. Therefore, we prepared a multi-scale model of posterior vertebra with continuum laminar complex model combined with micro-FE model of a pedicle section. The results showed that stress at the contralateral pars and pedicle increased after unilateral pars fracture simulation. High-stress regions were found around the outer boundaries of the pedicle. This model and information are helpful in understanding the stress changes in the pedicle and can be used for adaptive remodelling studies.     

Biomechanical effects of posterior pedicle fixation techniques on the adjacent segment for the treatment of thoracolumbar burst fractures: a biomechanical analysis

Abstract

Posterior pedicle fixation technique is a common method for treating thoracolumbar burst fractures, but the effect of different fixation techniques on the postoperative spinal mechanical properties has not been clearly defined, especially on adjacent segments. A finite element model of T10-L2 with moderate T12 vertebra burst fracture was constructed to investigate biomechanical behavior of three posterior pedicle screw fixation techniques. Compared with traditional short-segment 4 pedicle screw fixation (TS-4) and intermediate long-segment 6 pedicle screw fixation (IL-6), mono-segment 4 pedicle screw fixation (MS-4) provides a safer surgical selection to prevent the secondary degeneration of adjacent segments in the long-term.     

Antler regeneration: a dependent process of stem tissue primed via interaction with its enveloping skin

Deer antlers are unique mammalian appendages in that each year they are cast and fully regenerate from permanent bony protuberances, called pedicles. In a previous study, we found that there is a difference in the degree of association between pedicle bone and its enveloping skin: tight at the distal third and loose at the proximal two thirds of a pedicle stump. The distal part has been termed the "potentiated" region, and the proximal part the "dormant" region. In the present study, pedicle stumps were artificially created in yearling sika deer by cutting off the tissue distal to either the potentiated or the dormant region. A piece of impermeable membrane was then inserted into the space between the bone and the skin of each treated pedicle stump, while the control pedicles had the same surgery without membrane insertion. The results showed that the inserted membrane blocked pedicle skin participation in the process of antler regeneration. All three potentiated bony pedicle stumps regenerated skin-less antlers; whereas, one of the three dormant bony pedicle stumps failed to regenerate any antler tissue. The other two dormant stumps eventually regenerated normal antlers; however, this only occurred after loss of the inserted membrane. No antler tissue regenerated from the dormant stumps while the inserted membrane remained in place (up to 55 days). All control pedicle stumps regenerated normal antlers. Therefore, we conclude that it is the pedicle bone, but not pedicle skin, that gives rise to regenerating antlers, and that pedicle bone can acquire the potential to regenerate an antler only when it is primed via interaction with its enveloping skin.     

The pure posterior pedicle procedure for breast reduction

The inferior pedicle technique, which has already become classic, employs a glandular areola-bearing pedicle whose source of vascularization is primarily posterior. In fact, the inferior pedicle is a posterior pedicle with an inferior border. After systematically and progressively reducing this inferior border, I have completely eliminated it. The pure posterior pedicle that results is independent of the inframammary fold. It is vascularized by means of the pectoral muscle and fascia, as has been demonstrated by injection studies of the thoracoacromial artery in fresh cadavers. The resulting mammary reduction technique retains the advantages of the inferior pedicle technique while avoiding its major inconveniences: dependence on the inframammary fold, bulging at the inferior base of the pedicle, and the necessity of low positioning for the breast.     

Anchorage of the nucleolus in the pore complex-lamina by a DNA-bearing structure masked in situ in rat liver nuclei

We have developed a method by which nuclear shells containing nucleoli can be isolated from membrane-depleted rat liver nuclei. This method involves the removal of the internal chromatin. This chromatin is expelled from the nuclear shell using combinations of low and high ionic strength buffers. The expelled internal part is subsequently digested with DNase I or micrococcal nuclease. Examination by electron microscopy of the nuclear and the nucleolar structures at various steps of the isolation procedure shows that the nucleoli are anchored in the peripheral lamina by a pedicle that is continuous with an intranucleolar network. This network is masked in situ by nucleolar granules. The pedicle and the network which support the nucleolar DNA are composed mainly of non-histone proteins insoluble in 2M NaCl.     

Anchorage of the nucleolus in the pore complex-lamina by a DNA-bearing structure masked in situ in rat liver nuclei

We have developed a method by which nuclear shells containing nucleoli can be isolated from membrane-depleted rat liver nuclei. This method involves the removal of the internal chromatin. This chromatin is expelled from the nuclear shell using combinations of low and high ionic strength buffers. The expelled internal part is subsequently digested with DNase I or micrococcal nuclease. Examination by electron microscopy of the nuclear and the nucleolar structures at various steps of the isolation procedure shows that the nucleoli are anchored in the peripheral lamina by a pedicle that is continuous with an intranucleolar network. This network is masked in situ by nucleolar granules. The pedicle and the network which support the nucleolar DNA are composed mainly of non-histone proteins insoluble in 2M NaCl.     

Effects of insulin-like growth factor 1 and testosterone on the proliferation of antlerogenic cells in vitro.

Androgen hormones and growth factors are implicated in pedicle formation and antler transformation in deer. The potential to form a pedicle and an antler is only found in the antlerogenic periosteum (AP) overlying the presumptive antler growth region. Histological studies (Li and Suttie, '94) showed that AP consists of an inner cellular layer and an outer fibrous layer. Pedicle and antler are mainly derived from the cellular layer cells of the AP. Ossification takes place in four stages: intramembranous (IMO), transitional (OPC), pedicle endochondral (pECO) and antler endochondral (aECO). However, the precise mechanism whereby androgen hormones and growth factors control pedicle and antler formation is unknown. The aim of this study was to use cell culture techniques to investigate how testosterone and IGF1 affects the proliferation of antlerogenic cells from the four ossification stages of pedicle/antler in vitro. The results showed that in serum-free medium IGF1 stimulated the proliferation of antlerogenic cells from all four ossification stages in a dose-dependent manner. In contrast, testosterone alone did not show any mitogenic effects on these antlerogenic cells. However, in the presence of IGF1, testosterone increased proliferation of the antlerogenic cells from the IMO and the OPC stages (pedicle tissue), and reduced proliferation of the antlerogenic cells from transformation point (TP) and aECO stages (antler tissue). Therefore, the results from the present in vitro study support the in vivo findings that androgen hormones stimulate pedicle formation but inhibit antler growth. The change in the mitogenic effects of testosterone on antlerogenic cells from positive to negative occurs approximately at the change in ossification type from OPC to pECO. Therefore, these results reinforce the hypothesis that the transformation from a pedicle to an antler takes place at the time when the ossification type changes from OPC to pECO rather than at the time when the pedicle grows to its full species-specific height.     

Development of the pedicle in the articulate brachiopod Terebratalia transversa (Brachiopoda,Terebratulida)

Summary The development of the pedicle in the articulate brachiopod Terebratalia transversa has been examined by electron microscopy. The posterior half of the free-swimming larva comprises a non-ciliated pedicle lobe that contains the primordium of the juvenile pedicle at its distal end. During settlement at five to six days post-fertilization, the pedicle lobe secretes a sticky sheet that attaches the larva to the substratum. As metamorphosis proceeds, the epithelium in the posterior half of the pedicle lobe produces a thin overlying cuticle, and the pedicle primordium develops into a stalk-like anchoring organ. The juvenile pedicle protrudes through the gape that occurs between the posterior margins of the shell valves. A cup-like canopy, called the pedicle capsule, lines the posterior end of the shell and surrounds the newly formed pedicle. The core of the juvenile pedicle is filled with a solid mass of connective tissue. Numerous tonofibrils occur in the pedicle epithelium, and the overlying cuticle consists of amorphous material covered by a thin granular fringe. By one year post-metamorphosis, a body cavity develops anterior to the pedicle. Two pairs of adjustor muscles extend from the posterior end of the shell and traverse the cavity to insert in the pedicle. The connective tissue core of the pedicle in sub-adult specimens lacks muscle cells but contains numerous fibroblasts and collagen fibers. Three regions are recognizable in the connective tissue compartment of the adult pedicle: a subepithelial layer of non-fibrous connective tissue, a central fibrous zone, and a proximal mass of tissue that resembles cartilage.List of abbreviations as adhesive sheet - bc body cavity - bv brachial valve of shell - cf collagen fibrils - ct connective tissue - cu cuticle - di diductor muscle - ec epithelial cell - f fibroblast - fz fibrous zone - g gut - gc granular cell - gd gastric diverticulum - ht hinge tooth - ia interarea of pedicle valve - icl inner cuticular layer - lo lophophore - lu lumen of gut - m mesenchyme - ma mantle - ml mantle lobe - ocl outer cuticular layer - p periostracum - pc pedicle capsule - pce pedicle capsule epithelium - pcl pedicle collar of shell - pcn pedicle connectives - pd pedicle - pe pedicle epithelium - pl pedicle lobe - pv pedicle valve of shell - pzc proximal zone of cartilage-like tissue - s substratum - sel subepithelial layer - t tendon - tf tonofibril - vam ventral adjustor muscle     

Clinical and basic research on occipito-cervico-dorsal flaps: including a study of the anatomical territories of dorsal trunk vessels

The authors have carried out a clinical study of all the patients who underwent reconstructions with occipito-cervico-dorsal flaps in their department between 1994 and 2003 and analyzed the outcomes of the surgery. The reconstructed areas ranged from the cheek to the anterior chest. Twenty-eight cases underwent reconstruction with microvascular augmented occipito-cervico-dorsal flaps, and four were reconstructed with single pedicle occipito-cervico-dorsal flaps. In five cases, distal partial necrosis was observed. The largest flap size was 43 x 23 cm (5 x 5-cm pedicle). In the microvascular augmented occipito-cervico-dorsal flaps, the circumflex scapular artery and veins were used in 28 cases, and dorsal intercostal perforators were used together with circumflex scapular artery and veins in five cases. The follow-up term was between 1 and 8 years. Neck scar contractures were released in all cases, and good results were obtained not only functionally but also aesthetically. In an anatomical study, the authors used 20 preserved cadavers and took angiograms of the dorsal region. Five cadavers were used to confirm the territory of each of the vessels that have close relations to the occipito-cervico-dorsal flap (the occipital artery, transverse cervical artery, circumflex scapular artery, and dorsal intercostal perforator artery). Each anatomical territory was clearly seen and its area identified.     

The tunneled supraclavicular island flap: an optimized technique for head and neck reconstruction

Reconstructive procedures in the head and neck region use a wide range of flaps for defect closure. The methods range from local, mostly myocutaneous flaps and skin grafts to free microsurgical flaps. To ensure a satisfactory functional and aesthetic result, good texture and color of the flap are always essential. Moreover, the donor-site defect needs to be reduced, with no resulting functional or aesthetic impairment. We have found that the shoulder is a region providing an optimum skin texture match to the neck and face. In cadaver dissection, a vascular pedicle extending from the transversal cervical artery with two accompanying veins was found to vascularize a defined region around the shoulder cap. In line with these findings, the previously described fasciocutaneous island flap, nourished by the supraclavicular artery, was developed further and used purely as a subcutaneously tunneled island flap. The tunneling maneuver significantly improves the donor site by reducing scarring. The flap is characterized by a long subcutaneous pedicle of up to 20 cm. The pivot point is in the supraclavicular region and allows the flap to be used in the upper chest, neck, chin, and cheek. In this article, we introduce the anatomic features and present clinical cases underlining the surgical possibilities of the flap in reconstructive procedures with expanded indications.     

Correction of extracapsular temporomandibular joint ankylosis with a cervical subcutaneous pedicle flap

A new method of correcting extracapsular temporomandibular joint ankylosis with a cervical subcutaneous pedicle flap is described. In this procedure, a cervical subcutaneous pedicle flap with or without platysma is introduced into the oral cavity through a tunnel to repair the defect after the buccal scar is excised and the normal oral opening is restored. Sixteen consecutive patients underwent the surgery, and good results were obtained.     

Flap prefabrication in the head and neck: a 10-year experience

Tissue neovascularized by implanting a vascular pedicle can be transferred as a "prefabricated flap" based on the blood flow through the implanted pedicle. This technique potentially allows any defined tissue volume to be transferred to any specified recipient site, greatly expanding the armamentarium of reconstructive options. During the past 10 years, 17 flaps were prefabricated and 15 flaps were transferred successfully in 12 patients. Tissue expanders were used as an aid in 11 flaps. Seven flaps were prefabricated at a distant site and later transferred using microsurgical techniques. Ten flaps were prefabricated near the recipient site by either transposition of a local vascular pedicle or the microvascular transfer of a distant vascular pedicle. The prefabricated flaps were subsequently transferred as island pedicle flaps. These local vascular pedicles can be re-used to transfer additional neovascularized tissues. Common pedicles used for neovascularization included the descending branch of the lateral femoral circumflex, superficial temporal, radial, and thoracodorsal pedicles. Most flaps developed transient venous congestion that resolved in 36 to 48 hours. Venous congestion could be reduced by incorporating a native superficial vein into the design of the flap or by extending the prefabrication time from 6 weeks to several months. Placing a Gore-Tex sleeve around the proximal pedicle allowed for much easier pedicle dissection at the time of transfer. Prefabricated flaps allow the transfer of moderate-sized units of thin tissue to recipient sites throughout the body. They have been particularly useful in patients recovering from extensive burn injury on whom thin donor sites are limited.     

Strategic considerations on the configuration of free flaps and their vascular pedicles combined with Ilizarov distraction in the lower extremity

For the injury of the lower leg associated with both bone and soft-tissue defect, the combined free flap and the Ilizarov distraction method were described as a useful treatment modality. During the procedure of distraction, however, revisions were frequently needed to change the pin position or to change the flap configuration. In case of flap ischemia, distraction should be delayed or abandoned. Then, a vascularized bone transfer might be necessary. To avoid these complications and achieve safe distraction, the configuration of the flap with its vascular pedicle should be carefully planned in terms of the future bony lengthening procedures and the concomitant soft-tissue changes of the lower leg. According to the response of local tissue to the distraction process, the lower limb can be divided into four compartments (active mobile, passive mobile, receptive, and restrictive). The configuration of the transferred free flap with its vascular pedicle can be classified into five types. To minimize the undue forces to the vascular pedicle and reduce the possibility of vascular compromise, the transferred free flap should have the configuration that its vascular pedicle lies in the territory of the mobile compartment. In performing free-tissue transfer combined with the Ilizarov method in the lower extremity, the configuration of the flap with its vascular pedicle should be carefully planned, and the characteristics of lower leg tissue should be kept in mind during the distraction.     

TRAM flap safety optimized with intraoperative Doppler

Anatomic studies have clearly documented the variable position of the deep superior epigastric vessels in the rectus abdominis muscle. In our opinion, only that part of the rectus abdominis muscle containing the vascular pedicle should be transposed with the TRAM flap. The Doppler probe provides a simple method of identifying the dominant intramuscular vascular axis. It consistently alerts the surgeon to any unusual position of a vessel at the costal margin or within the rectus abdominis muscle. This knowledge enables a conservative yet safe dissection of the vascular pedicle, rectus abdominis muscle, and its sheath. This in turn will enable a competent abdominal closure. The Doppler technique is safe, simple, quick, noninvasive, familiar to most surgeons, and applicable to all patients.     

QTL for pubertal and seasonality traits in male Père David's x red deer interspecies hybrids

The unique Pere David's (Elaphurus davidianus) x red deer (Cervus elaphus) backcross hybrid has been used to search for evidence of quantitative trait loci (QTL) for antler pubertal (date and live weight at pedicle initiation) and antler seasonality (date of antler cleaning and casting) traits in temperate species of deer. Analyses using marker information revealed evidence for a QTL for date at pedicle initiation (LOD = 3.7) and live weight at pedicle initiation (LOD = 3.1). These QTL explained 13% and 11% of the phenotypic variance in these traits, respectively.     

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.