Akihiro Fukui

The arterialised venous flap: experimental studies and a clinical case

It is accepted that small arterialised venous flaps (AVF) can survive on a recipient bed with poor blood supply but survival of larger flaps is not always satisfactory. Possible reasons for this include the flap anatomy, particularly the pattern of the venous network, or factors at the recipient site. To investigate the possible factors in the flap design and the recipient site of an arterialised venous flap, we studied the relationship between (1) size of the artery used to arterialise the flap at the recipient site and the survival rate and (2) the number of draining veins and the survival rate, using rabbit ear skin flap models. Our results suggest that AVFs may become necrotic in the presence of a relative excess of arterial blood inflow, and that two exit veins are more effective than one. We also report a case where a 10 x 15 cm sized free AVF harvested from the lower extremity survived on the forearm.

A reverse ulnar hypothenar flap for finger reconstruction

A reverse-flow island flap from the hypothenar eminence of the hand was applied in 11 patients to treat palmar skin defects, amputation injuries, or flexion contractures of the little finger. There were three female and eight male patients, and their ages at the time of surgery averaged 46 years. A 3 × 1.5 to 5 × 2 cm fasciocutaneous flap from the ulnar aspect of the hypothenar eminence, which was located over the abductor digiti minimi muscle, was designed and transferred in a retrograde fashion to cover the skin and soft-tissue defects of the little finger. The flap was based on the ulnar palmar digital artery of the little finger and in three patients was sensated by the dorsal branch of the ulnar nerve or by branches of the ulnar palmar digital nerve of the little finger. Follow-up periods averaged 42 months. The postoperative course was uneventful for all patients, and all of the flaps survived without complications. The donor site was closed primarily in all cases, and no patient complained of significant donor-site problems. Satisfactory sensory reinnervation was achieved in patients who underwent sensory flap transfer, as indicated by 5 mm of moving two-point discrimination. A reverse island flap from the hypothenar eminence is easily elevated, contains durable fasciocutaneous structures, and has a good color and texture match to the finger pulp. This flap is a good alternative for reconstruction of palmar skin and soft-tissue defects of the little finger. (Plast. Reconstr. Surg. 106: 828, 2000.)

Traumatic amputation of digits: The fate of remaining blood: An experimental and clinical study

Experimental studies on rabbit ears amputated by either a clean sharp division or severed by a crushing blow showed that twice as much blood remained in the crush group. Microthrombi and tissue thrombi were seen in this group only. A review of 142 digital replantations performed over a 10 year period showed 126 survivals. Ninety-three were complete amputations and 80 of these survived; 49 were incomplete amputations and 46 survived after revascularization attemps. Of 74 clear amputations, 68 survived; of 68 crush-type amputations, 58 survived. Circulatory disturbances occurred in 36 replanted digits; 16 could not be salvaged. The primary cause of complications was venous obstruction. In 80 digital replantations done from January, 1974, to December, 1975, success was obtained in 75 (93.75 percent). Irrigation of vessels of the severed part is done only in cases of double level amputation, severely crushed or those due to avulsion. Heparin, low molecular weight dextran, urokinase, and antibiotics are given for several days after operation.

Locking wrist with synovial chondromatosis: report of two cases.

A 60-year-old farmer presented with the complaint that for approximately 1 year his right wrist sometimes locked with pain when he lifted a heavy object. There was no history of injury. Physical examination showed swelling of the dorsal aspect of the distal radioulnar joint with local tenderness. The wrist had a full range of motion. X-ray films demonstrated three radiopaque bodies lying in the distal radioulnar joint (Fig. I), with the distal one lodged in the radiolunate joint when the wrist locked (Fig. 2). At surgery. the synovium and all chondral bodies were excised (Fig. 3). The triangular fibrocartilage was torn at the ulnopalmar margin, and this was repaired. The wrist locking was probably due to the free body that was displaced from the distal radioulnar joint through the torn triangular fibrocartilage into the radiocarpal joint. Microscopically, the synovium was characterized by the presence of multiple nodular cartilaginous bodies. After 2 weeks of cast immobilization, the patient was pain-free without locking or limitation of wrist motion.

The pedicled venous flap. An experimental study

Musculocutaneous pedicled venous flaps on the dorsum of rats survived at a statistically significantly higher rate than musculocutaneous composite grafts (p < 0.01). With a Silastic sheet (Dow Corning) beneath, both composite grafts and pedicled venous flaps necrosed. When a Silastic sheet with holes in it to allow some revascularisation from the bed was placed beneath, the survival rate was significantly better than with a complete Silastic sheet (p < 0.01). These results demonstrate that pedicled venous flap survival depends both on the draining vein, and revascularisation from the underlying bed.

The pedicled venous flap. Clinical applications

Experimental findings of survival of pedicled venous flaps were clinically applied in seven cases for traumatic skin defects on digits. Five flaps which were transferred to or on digits other than the thumb survived, but two flaps from the index to the thumb developed partial necrosis. In order to prevent flap necrosis, the draining vein should be short.

Progenitor endothelial cells on vascular grafts: An ultrastructural study

The morphology of progenitor endothelial cells on vascular graft surfaces is addressed in this report. Such cells were seen to attach to intima-expressed CD34 and Flk-1 antigen and showed positive 5-bromo-2-deoxyuridine (BrdU) uptake. We examined CD34 and Flk-1 antigen-expressing endothelial progenitor cells three-dimensionally using confocal laser scanning microscopy (CLSM). Under detailed CLSM observation, through an ameboid-form cell, these progenitor endothelial cells changed from a globular to a flattened form. We also investigated these morphological changes using scanning electron microscopy. From these results, progenitor endothelial cells were observed not only near the advancing edge of endothelium, but also around the developing intimal site. Their form also changed from globular to flattened as observed in the CLSM results. These morphological changes were seen more frequently near the advancing edge and around the developing intimal site. They attached directly to vascular prosthesis fibers and likewise covered the graft luminal surface. Progenitor endothelial cells in any form had a common surface structure. We conclude from our results that progenitor endothelial cells can attach to graft fibers directly without clotting and directly cover the graft luminal surfaces.

Innervated radial thenar flap combined with radial forearm flap transfer for thumb reconstruction.

A radial thenar flap combined with radial forearm flap was used for the reconstruction of the ipsilateral thumb in four patients. Vascular supply of the combined flap was based on the radial artery and extending the vascular pedicle to the superficial palmar branch of the radial artery. The flap was sensated by the palmar branch of the superficial radial nerve. The size of the flap averaged 15 x 5 cm and the innervated region of the thenar eminence was an area approximately 5 x 3 cm located over the proximal parts of the abductor pollicis brevis and opponens pollicis muscles. The flap was transferred as a free flap in three patients and as an advancement flap in one patient. The flaps survived completely without complications. Satisfactory restoration of sensation was achieved in the flap area, as shown by 6 mm of average moving two-point discrimination. This combined flap may be a feasible reconstructive option for large palmar defects of the fingers such as degloving injuries.

Partial soleus muscle island flap transfer using minor pedicles from the posterior tibial vessels.

A new method for partial soleus muscle island flap transfer using minor pedicles from the posterior tibial vessels was designed and executed. A portion of the soleus muscle body that was slightly wider than the defect was harvested with minor pedicles. The muscle flap was transposed by turning it over or by creating an island flap. Skin grafts were applied to the exposed muscle. This new type of muscle flap was applied to six patients with a pretibial skin defect at the lower third of the leg. It was used for treatment of an open fracture with an associated skin defect in four patients, chronic osteomyelitis in one patient, and a recurrent stasis ulcer in one patient. In all patients the transferred muscle flap survived completely.

The role of serum imbibition for skin grafts

Numerous studies of grafted skin suggest that full-thickness skin grafts are nourished by exudate from the recipient bed called a serum imbibition. However, whether serum imbibition by itself is sufficient for nourishment of skin grafts has not been shown definitely and directly. To clarify the role of serum imbibition, we performed a comparative study between 20 skin grafts and 20 musculocutaneous flaps. The nourishment of the cell in the skin graft is by serum imbibition. That in musculocutaneous flaps is mainly derived from blood supply. We evaluated the nourishment by means of the unique characteristics of the cell cycle. Once cells are put into a synthetic phase, they cannot reverse or stop the progress of the cell cycle. To take advantage of this characteristic of the cell cycle, prewounding methods (40 flaps were lifted once and put back to the original sites prior to the evaluation) were intended for the cells in pre-elevated skin to turn into a proliferating phase. Cells were examined by antibody against proliferating cell nuclear antigen immunohistologically, to determine whether they had turned into the proliferating phase or not. After 3 days, all flaps were reelevated; half (20 flaps) had their muscle layer and the neurovascular bundle removed to make a full-thickness skin graft. The rest (20 flaps) were only lifted. They were sutured back to the original sites. Ten skin grafts and musculocutaneous flaps each were harvested at 3 hours (1st day) and at 11 days (11th day) after the second operation. Bromodeoxyuridine, which is a thymidine analog and is taken into the cells in the synthetic phase, was introduced intraperitoneally 2 hours before the harvest. All flaps and grafts were evaluated histologically and immunohistologically. Proliferating cell nuclear antigen analysis showed that the prewounding method induced the cells of skin grafts and musculocutaneous flaps to proliferate before the implantation. Regarding the bromodeoxyuridine uptake, no significant differences could be seen between skin grafts and musculocutaneous flaps irrespective of their different nourishment. No structural changes, such as degenerative or necrotic, could be seen at the hair follicle and other glands even at the 11th day. Almost all of the layers of skin grafts survived as long as they were checked by light microscopy (hematoxylin and eosin stain). No differences could be seen between musculocutaneous flaps and skin grafts or between the 1st and 11th days in this study. We concluded that serum imbibition is sufficient for nourishment of skin grafts, just as blood supply is sufficient for nourishment of musculocutaneous flaps.