Hirotaka Asato

One-stage transfer of the latissimus dorsi muscle for reanimation of a paralyzed face: a new alternative.

&NA; The two‐stage method combining neurovascular freemuscle transfer with cross‐face nerve grafting is now a widely accepted procedure for dynamic smile reconstruction in cases with long established unilateral facial paralysis. Although the results are promising, the two operations, about 1 year apart, exert an economic burden on the patients and require a lengthy period before obtaining results. Sequelae such as hypoesthesia, paresthesia, and conspicuous scar on the donor leg for harvesting a sural nerve graft also cannot be disregarded. To overcome such drawbacks of the two‐stage method, we report a refined technique utilizing one‐stage microvascular free transfer of the latissimus dorsi muscle. Its thoracodorsal nerve is crossed through the upper lip and sutured to the contralateral intact facial nerve branches. Reinnervation of the transferred muscle is established at a mean of 7 months postoperatively, which is faster than that of the two‐stage method. In our present series with 24 patients, 21 patients (more than 87 percent) believed that their results were excellent or satisfactory, which also compares well with the results of the two‐stage method combining free‐muscle transfer with cross‐face nerve graft. (Plast. Reconstr. Surg. 102: 941, 1998.)

Mandibular reconstruction using microvascular free flaps: a statistical analysis of 178 cases.

&NA; For this article, 178 consecutive cases of mandibular reconstruction using microvascular free flaps and performed from 1979 to 1997 were studied. The purpose of this report is to compare flap success rates, complications, and aesthetic and functional results. The ages of the 131 men and 47 women ranged from 13 to 85 years, with an average of 55 years. Donor sites included the rib (11 cases), radius (one case), ilium (36 cases), scapula (51 cases), fibula (34 cases), and soft‐tissue flaps with implant (45 cases). Complications included total flap necrosis, partial flap necrosis, major fistula formation, and minor fistula formation. The rate of total flap necrosis involving the ilium and fibula was significantly higher than that of all other materials combined (p < 0.05). The overall rate of implant plate removal, which resulted from the exposure or fracture of the plate, was 35.6 percent (16 of 45 cases). Each mandibular defect was classified by the extent of the bony defect and by the extent of the soft‐tissue defect. The extent of the mandibular bony defect was classified according to the HCL method of Jewer et al. The extent of the soft‐tissue defect was classified into four groups: none, skin, mucosal, and through‐and‐through. According to these classifications, functional and aesthetic assessments of deglutition and contour were performed on 115 subjects, and speech was evaluated in 110. To evaluate the postoperative results, points were assigned to each assessment of deglutition, speech, and mandibular contour. Statistical analysis between pairs of bone‐defect groups revealed that there was no significant difference in each category. Regarding deglutition, statistical analysis between pairs of soft‐tissue‐defect groups revealed there were significant differences (p < 0.05) between the none and the mucosal groups and also between the none and the through‐and‐through groups. Regarding speech, there was a significant difference (p < 0.05) between the none and the through‐and‐through groups. Regarding contour, there were significant differences (p < 0.01) between the none and the through‐and‐through groups and between the mucosal and the through‐and‐through groups. The points given for each function, depending on the reconstruction material, revealed that there was no significant difference between pairs of material groups. From this prospective study, the authors have developed an algorithm for oromandibular reconstruction. When the bony defect is lateral, the ilium, fibula, or scapula should be chosen as the donor site, depending on the extent of the soft‐tissue defect. When the bony defect is anterior, the fibula is always the best choice. When the soft‐tissue defect is extensive or through‐and‐through with an anterior bony defect, the fibula should be used with other soft‐tissue flaps. (Plast. Reconstr. Surg. 108: 1555, 2001.)

Comparative Evaluation in Pharyngo-oesophageal Reconstruction: Radial Forearm Flap compared with Jejunal Flap. A 10-year experience

We reviewed 109 consecutive patients with cancer of the hypopharynx or cervical oesophagus who underwent free flap transfer for immediate reconstruction after total pharyngolaryngo-oesophagectomy. The free flaps used were either free jejunal (n = 70) or radial forearm flaps (n = 39). Significantly more fistulas (3/70 compared with 15/39, p < 0.0001) and strictures (6/64 compared with 13/33, p = 0.0008) developed in the radial forearm than the jejunal flap group. However, functional donor site morbidity was minimal and there were no cases of total flap necrosis in the forearm flap group. We consider that the free jejunal flap should be the first choice for total reconstruction of pharyngo-oesophageal defects. However, the forearm flap is suitable for elderly, high risk patients, because it is less invasive and has minimal donor site morbidity, which facilitates early recovery.

Optimal Combination of Soluble Factors for Tissue Engineering of Permanent Cartilage from Cultured Human Chondrocytes

Since permanent cartilage has poor self-regenerative capacity, its regeneration from autologous human chondrocytes using a tissue engineering technique may greatly benefit the treatment of various skeletal disorders. However, the conventional autologous chondrocyte implantation is insufficient both in quantity and in quality due to two major limitations: dedifferentiation during a long term culture for multiplication and hypertrophic differentiation by stimulation for the redifferentiation. To overcome the limitations, this study attempted to determine the optimal combination in primary human chondrocyte cultures under a serum-free condition, from among 12 putative chondrocyte regulators. From the exhaustive 212 = 4,096 combinations, 256 were selected by fractional factorial design, and bone morphogenetic protein-2 and insulin (BI) were statistically determined to be the most effective combination causing redifferentiation of the dedifferentiated cells after repeated passaging. We further found that the addition of triiodothyronine (T3) prevented the BI-induced hypertrophic differentiation of redifferentiated chondrocytes via the suppression of Akt signaling. The implant formed by the human chondrocytes cultured in atelocollagen and poly(l-latic acid) scaffold under the BI + T3 stimulation consisted of sufficient hyaline cartilage with mechanical properties comparable with native cartilage after transplantation in nude mice, indicating that BI + T3 is the optimal combination to regenerate a clinically practical permanent cartilage from autologous chondrocytes.

Free rectus abdominis muscle reconstruction of the anterior skull base

Pericranial flaps and galeal frontalis myofascial flaps can be useful for separating the cranial space from the paranasal sinuses and the nasopharynx, but they cannot provide reliable separation and protection of the brain from bacterial flora of the upper airway in patients who previously have received high dose radiation therapy and undergone craniotomy, or required extensive resection of the cranial base. The free rectus abdominis muscle flap, on the other hand, can provide a good alternative for reconstruction of the anterior skull base in such difficult cases, and give good results. In six cases using free rectus abdominis flaps, there have been neither cerebrospinal fluid leaks nor meningitis. There was one flap failure due to venous congestion.

Versatility of a free inferior rectus abdominis flap for head and neck reconstruction : analysis of 200 cases

Between 1984 and 1991, 200 inferior rectus abdominis muscle and musculocutaneous free flap transfers were performed for reconstruction of defects or deformities resulting from removal of cancer in the head and neck region. Primary reconstruction was performed in 190 of 200 cases (95 percent), and secondary reconstruction in 10 cases (5 percent). The most common indication was tongue cancer in 78 patients, followed by cancer of the oropharynx. Total flap necrosis occurred in 10 cases (5 percent) and partial necrosis in two cases (1 percent). Donor-site morbidity was minimal. One of the distinct advantages of this flap is that the volume of the muscle and/or the fatty tissue attached to a given skin paddle can be readily adjusted to suit individual requirements. This flap has proven particularly useful for complex or large tissue defects in the head and neck region.

Synergistic effects of FGF-2 with insulin or IGF-I on the proliferation of human auricular chondrocytes.

Chondrocyte preparation with the safety and efficiency is the first step in cartilage regenerative medicine. To prepare a chondrocyte proliferation medium that does not contain fetal bovine serum (FBS) and that provides more than a 1000-fold increase in cell numbers within approximately 1 month, we attempted to use the medium containing 5% human serum (HS), but it exerted no more than twofold increase in 2 weeks. To compensate for the limited proliferation ability in HS, we investigated the combinational effects of 12 factors [i.e., fibroblast growth factor(FGF)-2, insulin-like growth factor(IGF)-I, insulin, bone morphogenetic protein-2, parathyroid hormone, growth hormone, dexamethasone, 1α25-dihydroxy vitamin D3, L-3,3′,5′-triodothyronine, interleukine-1 receptor antagonist, 17β-estradiol, and testosterone] on the proliferation of human auricular chondrocytes by analysis of variance in fractional factorial design. As a result, FGF-2, dexamethasone, insulin, and IGF-I possessed promotional effects on proliferation, while the combination of FGF-2 with insulin or IGF-I synergistically enhanced the proliferation. Actually, the chondrocytes increased 7.5-fold in number in 2 weeks in a medium containing 5% HS with 10 ng/ml FGF-2, while the cell number synergistically gained a 10–12-fold increase with 5 μg/ml insulin or 100 ng/ml IGF-I in the same period. The proliferation effects were more enhanced at a concentration of 100 ng/ml for FGF-2, and especially for the combination of 100 ng/ml FGF-2 and 5 μg/ml insulin (approximately 16-fold within 2 weeks). In the long-term culture with repeated passaging, this combination provided more than 10,000-fold within 8 weeks (i.e., passage 4). Thus, we concluded that such a combination of FGF-2 with insulin or IGF-I may be useful for promotion of auricular chondrocyte proliferation in a clinical application for cartilage regeneration.

Tissue Expansion in Facial Reconstruction

The tissue expansion technique is advantageous in facial reconstruction because it makes it possible to resurface even wider defects with neighboring skin similar in color and texture and superior to skin obtained elsewhere, thereby surpassing conventional methods. However, there still remain some problems relating to procedural details, such as the selection of tissue expanders and sites of their insertion; the design, elevation, suturing, and fixation of the expanded flap; and the management of free margins such as the lower lip and lower eyelid. In each case, some modification is required with respect to the status of the defect. The experiences encountered in a series of 23 patients are described, with illustration of several representative cases, and advantages and problems are discussed.

Neurovascular free muscle transfer combined with cross-face nerve grafting for the treatment of facial paralysis in children

&NA; Microneurovascular free muscle transfer is fast becoming a standardized procedure in the treatment of established or long‐standing facial paralysis. However, there is no general agreement as to whether muscle transfer should be employed for children who still are growing. A patients natural growth may influence or disturb reproduction of a smile, or a child may not be able to collaborate with postoperative rehabilitation sufficiently well to obtain a satisfactory result. One may hesitate to employ the procedure for children aged under 10 out of fear of its technical difficulties. To investigate the influence of age, the results experienced by 23 patients under the age of 15 who underwent free muscle transfer combined with crossface nerve grafting were compared with those of adult patients. The treatment employed was a two‐stage operation consisting of cross‐face nerve grafting and subsequent free muscle transfer. (Plast. Reconstr. Surg. 101: 1765, 1998.)

Reconstruction of the umbilicus using a single triangular flap

Many techniques for reconstruction of an absent umbilicus have been described; however, none has achieved a perfect result. We report a new alternative for constructing an umbilicus using a conical flap and present two representative clinical cases. Our technique creates an umbilicus with sufficient depth with good results, including maintenance of depth after more than 1 year.