Enhanced axon outgrowth of spinal motor neurons in co-culturing with dorsal root ganglions antagonizes the growth inhibitory environment.

Introduction: Forming a bridge made of functional axons to span the lesion is essential to reconstruct the motor circuitry following spinal cord injury (SCI). Dorsal root ganglion (DRG) axons are robust in axon growth and have been proved to facilitate the growth of cortical neurons in a process of axon-facilitated axon regeneration. However, whether DRG transplantation affects the axon outgrowth of spinal motor neurons (SMNs) that play crucial roles in motor circuitry remains unclear. Methods: We investigated the axonal growth patterns of co-cultured DRGs and SMN aggregates (SMNAs) taking advantage of a well-designed 3D-printed in vitro system. Chondroitin sulphate proteoglycans (CSPG) induced inhibitory matrix was introduced to imitate the inhibitory environment following SCI. Axonal lengths of DRG, SMNA or DRG & SMNA cultured on the permissive or CSPG induced inhibitory matrix were measured and compared. Results: Our results indicated that under the guidance of full axonal connection generated from two opposing populations of DRGs, SMNA axons were growth-enhanced and elongated along the DRG axon bridge to distances that they could not otherwise reach. Quantitatively, the co-culture increased the SMNA axonal length by 32.1 %. Moreover, the CSPG matrix reduced the axonal length of DRGs and SMNAs by 46.2 % and 17.7 %, respectively. This inhibitory effect was antagonized by the co-culture of DRGs and SMNAs. Especially for SMNAs, they extended the axons across the CSPG-coating matrix, reached the lengths close to those of SMNAs cultured on the permissive matrix alone. Conclusions: This study deepens our understanding of axon-facilitated reconstruction of the motor circuitry. Moreover, the results support SCI treatment utilizing the enhanced outgrowth of axons to restore functional connectivity in SCI patients.

An anatomical study of the tibial nerve branches innervating the posterior tibial artery.

The arteries of the lower limbs are innervated by vascular branches (VBs) originating from the lumbar sympathetic trunk and branches of the spinal nerve. Although lumbar sympathectomy is used to treat nonreconstructive critical lower limb ischemia (CLLI), it has limited long-term effects. In addition, the anatomical structure of tibial nerve (TN) VBs remain incompletely understood. This study aimed to clarify their anatomy and better inform the surgical approach for nonreconstructive CLLI. Thirty-six adult cadavers were dissected under surgical microscopy to observe the patterns and origin points of VBs under direct vision. The calves were anatomically divided into five equal segments, and the number of VB origin points found in each was expressed as a proportion of the total found in the whole calf. Immunofluorescence staining was used to identify the sympathetic nerve fibers of the VBs. Our results showed that the TN gave off 3-4 VBs to innervate the posterior tibial artery (PTA), and the distances between VBs origin points and the medial tibial condyle were: 24.7 ± 16.3 mm, 91.7 ± 66.1 mm, 199.6 ± 52.0 mm, 231.7 ± 38.5 mm, respectively. They were mainly located in the first (40.46%) and fourth (31.68%) calf segments, and immunofluorescence staining showed that they contained tyrosine hydroxylase-positive sympathetic nerve fibers. These findings indicate that the TN gives off VBs to innervate the PTA and that these contain sympathetic nerve fibers. Therefore, these VBs may need to be cut to surgically treat nonreconstructable CLLI.

A composite gluteofemoral flap for reconstruction of large pressure sores over the sacrococcygeal region.

BACKGROUND AND AIM: Gigantic pressure sores pose a daunting challenge for plastic surgeons. This paper presents a composite gluteofemoral flap for reconstruction of large pressure sores over the sacrococcygeal region. METHODS: In this anatomical study, 30 embalmed cadaveric lower limbs were used for dissection to observe the musculocutaneous perforators of the inferior gluteal artery and the longitudinal nutritional vascular chain of the posterior femoral cutaneous nerve. In this clinical study, eight patients underwent surgical harvest of the composite gluteofemoral flap for coverage of grade IV sacrococcygeal pressure sores. The size of the pressure sores ranged between 16 × 9 cm and 22 × 10 cm. RESULTS: The inferior gluteal artery was present in 26 cases and absent in four cases. It gave off two to four musculocutaneous branches with a diameter larger than 0.5 mm to the gluteus maximus. A direct cutaneous branch was given off at the inferior margin of the gluteus maximus, serving as a nutritional artery for the posterior femoral cutaneous nerve. The size of the flap harvested ranged between 22 × 9 cm and 32 × 10 cm. Flaps in seven patients survived uneventfully and developed epidermal necrosis at the distal margin in one case. An average 2-year follow-up revealed no recurrence of pressure sores. CONCLUSION: The composite gluteofemoral flap, being robust in blood supply, simple in surgical procedure, and large in donor territory, is an important addition to the armamentarium.

Revisit of the anatomy of the distal perforator of the descending genicular artery and clinical application of its perforator "propeller" flap in the reconstruction of soft tissue defects around the knee.

PURPOSE: In this article,we revisited the anatomy of the distal perforator of the descending genicular artery (DGA) and report the clinical application of its perforator propeller flap in the reconstruction of soft tissue defects around the knee. METHODS: Forty fresh human lower limbs were dissected to redefine the anatomy of the branches of the DGA and their perforators and the anatomical landmarks for clinical applications. Five patients underwent "propeller" distal anteromedial thigh (AMT) flaps based on DGA perforators for the reconstruction of post-traumatic (n = 4) and post-oncologic (n = 1) soft tissue defects occurring near the knee with a size ranging from 4.8 cm × 6.2 cm to 10.5 cm × 18.2 cm. RESULTS: A constant cutaneous perforator of the osteoarticular branch (OAB) of the DGA was found in the distal AMT fossa with a mean caliber of 1.2 ± 0.4 mm. It arose 9.4 ± 3.1 cm distally to the origin of the OAB and 4.0 ± 0.4 cm above the knee joint. The size of the harvested flaps ranged from 6.0 cm × 7.1 cm to 11.0 cm × 20.1 cm. All the flaps healed uneventfully at a mean period of 7.4 months. All the patients regained full range motion of the knee-joint. CONCLUSION: Our study provided evidence of the vascular supply and the clinical application of the distal AMT flap based on a constant perforator arising from the OAB of the DGA. This flap may be a versatile alternative for the reconstruction of the defects around the knee because of its consistent vascular pedicle, pliability and thinness, adequate retrograde perfusion, and the possible direct suture of the donor site.

The ulnar palmar perforator flap: anatomical study and clinical application.

BACKGROUND: Defects sustained at the little finger and the ulnar aspect of the hand are common and pedicled perforator flaps have unique advantages in resurfacing it. The purpose of this study is to reappraise the anatomy of the septocutaneous perforator in the postero-medial aspect of the hand and present our clinical experience in using perforator flaps based on it. METHODS: This study was divided into anatomical study and clinical application. In the anatomical study, 30 preserved upper limbs were used. Clinically, 16 patients with defects at the little finger or the ulnar aspect of the hand underwent reconstruction with flaps based on the perforator from the ulnar palmar artery of little finger. The defects ranged from 2.3 × 1.3 cm(2) to 5.7 × 3.0 cm(2). RESULTS: The septocutaneous perforator was constantly located 1.3 ± 0.3 cm superior to the fifth metacarpophalangeal joint with a diameter of 0.8 ± 0.2 mm. It travelled through the space between the superficial layer and the deep layer of hypothenar muscles, and ramified into three branches before entry into the skin. The ascending branch of the perforator has two patterns of anastomoses with the descending dorsal carpal branch of the ulnar artery: true anastomoses and choked anastomoses. Clinically, flaps in all 16 cases survived uneventfully, and donor sites healed without deformity. CONCLUSION: The location of the perforator at the postero-medial aspect of the hand is consistent; the ulnar palmar perforator flap is particularly suitable to cover defects in the little finger or the ulnar aspect of hand.

The posterolateral mid-forearm perforator flap: anatomical study and clinical application.

BACKGROUND: Defects sustained at the distal forearm are common and pedicled perforator flaps have unique advantages in resurfacing it. The purpose of this study is to reappraise the anatomy of the perforator in the posterolateral aspect of the mid-forearm and present our clinical experience on using perforator flaps based on it for reconstruction of defects in the distal forearm. METHODS: This study was divided into anatomical study and clinical application. In the anatomical study, 30 preserved upper limbs were used. Clinically, 11 patients with defects at the forearm underwent reconstruction with the posterolateral mid-forearm perforator flaps. The defects, ranging from 4.5 × 2.5 cm to 10.5 × 4.5 cm, were located at the dorsal aspect of the distal forearm in 6 cases and at the volar aspect of the distal forearm in 5 cases. RESULTS: Three patterns of the perforator were observed in the posterolateral aspect of the mid-forearm, which originated from the posterior interosseous artery, the proximal segment of the radial artery or the radial recurrent artery, and the middle segment of the radial artery, respectively. The perforator was located 11.8 ± 0.2 cm to 15.8 ± 0.4 cm inferior to the lateral humeral epicondyle. Clinically, flaps in 8 cases survived uneventfully, while the other 3 cases suffered mild marginal epidermal necrosis, which was cured with continuous dress changing. CONCLUSION: The location of the perforator at the posterolateral aspect of the mid-forearm is consistent; the posterolateral mid-forearm perforator flap is particularly suitable to cover defects in the distal one-third of the forearm.

Modified deep iliac circumflex osteocutaneous flap for extremity reconstruction: anatomical study and clinical application.

BACKGROUND: The classic deep iliac circumflex osteocutaneous flap with iliac crest has been one of the most commonly used flaps for mandibular reconstruction since its advent. However, the unnecessary bulk of the 'obligatory muscle cuff' limited its widespread use. The authors describe in this article the use of a modified deep iliac circumflex osteocutaneous flap with reduced bulk and great mobility between the skin and the bone components. METHODS: This study was divided into two parts: anatomical study and clinical application. In the anatomical study, 40 sides of adult cadaveric specimens perfused with red gelatin in the arteries were dissected with the anterior superior iliac spine and the inguinal ligament serving as the anatomical landmarks to observe the course and the branches of the deep circumflex artery, with its terminal part being given priority. Clinically, five patients received modified deep iliac circumflex osteocutaneous flaps for extremity reconstruction. RESULTS: The anatomical study showed that the terminal part of the deep circumflex iliac artery ended as a musculocutaneous perforator with a diameter of 1.0 ± 0.1 mm, which could be located 6.2 ± 1.2 cm posterior and 1.5 ± 0.6 cm lateral to the anterior superior iliac spine. As for clinical application, in four cases osteocutaneous flaps survived completely, while that in one case suffered partial loss of the skin component. CONCLUSIONS: The modified deep iliac circumflex osteocutaneous flap enjoys a great degree of mobility between the skin and the bone components; it has greater manoeuvrability compared to the conventional one for the reconstruction of complex three-dimensional defects. The donor site of the skin flap is confined to the lower abdominal region, facilitating direct closure.

Convenient coverage of soft-tissue defects around the knee by the pedicled vastus medialis perforator flap.

Various reconstructive methods have been reported for coverage of soft-tissue defects around the knee; however, there is still no report about the pedicled vastus medialis perforator flap; hence, this article aims to elaborate on this approach for resurfacing of defects around the knee. From January 2010 to December 2010, six patients with defect size ranging from 5.0 × 3.3 to 10.5 × 7.0 cm received soft-tissue coverage with the pedicled vastus medialis perforator flap. Among them, five cases were male, and the other female. The age of patients ranged from 20 to 52 years, with an average of 34.5 years. The injury of one patient was caused by being crushed by a heavy metal object, and the rest sustained injuries in traffic accidents. The defect in one case was located at the inferomedial aspect of the thigh, and the rest around the knee. Five flaps survived completely, while one case suffered marginal necrosis due to infection. The donor sites healed without complication. Postoperative follow-ups of the patients ranged from 1 to 18 months. Through the article, we demonstrate the feasibility of using the pedicled vastus medialis perforator flap for reconstruction of knee injuries, which makes the knowledge of the vastus medialis-related flap series more complete and also enriches the methods of repairing defects around the knee.

Vasculature at the medial aspect of the foot and clinical application of flaps based on it for forefoot reconstruction.

BACKGROUND: Detailed knowledge of the vasculature of the medial aspect of the foot has rarely been reported, but it is of tremendous importance for harvesting the flap in this area to cover defects of the foot and hand. Repair of soft-tissue defects at the dorsal forefoot remains a challenge in reconstructive surgery. The authors describe the use of the distally based saphenous neurovenofasciocutaneous flap at the medial aspect of the foot to cover this region. METHODS: This study was divided into two parts: an anatomical study and clinical application. In the anatomical study, 35 cadaveric feet were injected with red gelatin, five others were made as corrosive vascular casts, and then the main vessels distributed at the medial aspect of the foot were observed. Clinically, six cases of soft-tissue defects at the dorsal forefoot were reconstructed with distally based saphenous neurovenofasciocutaneous flaps. RESULTS: The anatomical study showed that (1) the vasculature pattern could roughly be classified into three types and (2) there were constant anastomoses between the above-mentioned arteries around the midpoint of the first metatarsal bone. In terms of clinical application, all flaps completely survived, and one patient had partial loss of skin graft. CONCLUSIONS: The blood supply to the medial aspect of the foot has multiple origins, on the basis of which of several flaps can be harvested, either a pedicled or free. Of particular clinical significance is the distally based saphenous neurovenofasciocutaneous flap, which is thin, is in the immediate vicinity of the forefoot, and has a reliable retrograde blood supply. This flap should be considered as a preferential way to reconstruct soft-tissue defects of the dorsal forefoot.