Radiographic analysis of growth in pediatric microsurgical toe-to-hand transfers

Microsurgical toe-to-hand transfers may provide improved hand function in children with absent digits. To date, documentation of the growth potential of these transferred digits has not been performed. This study reviewed the authors' series of pediatric toe-to-hand transfers, with specific attention paid to measuring growth by radiographic analysis. From 1995 to 2000, 23 toe-to-hand transfers were performed in 18 children. Age at time of transfer ranged from 2.8 to 13 years. Indications included constriction band syndrome, transverse deficiency, longitudinal deficiency, traumatic amputation, and vascular malformation. The transfers were successful in 22 of 23 procedures (96 percent success rate). Radiographic analysis of growth was performed using three criteria: (1) appearance of open epiphyseal plates, (2) comparison with preoperative radiographs, and (3) comparison with radiographs of the contralateral control toe. Epiphyseal plates remained open on postoperative radiographs in 27 of 28 phalanges (96 percent) at a mean of 12 months' follow-up (range, 1 to 36 months). The preoperative foot radiographs were compared with serial radiographs of the transferred toe over time. In 10 toe transfers with follow-up greater than 6 months (mean, 21 months), nine patients had increased bony length in the transferred digit. In four patients, radiographs of the toe transfer were compared with radiographs of the corresponding toe on the opposite foot. With a mean follow-up of 29 months, all patients had equal length measurements of the toe transfer with the contralateral toe control. These data provide objective evidence that digital growth potential is preserved in toe-to-hand transfers. Furthermore, this bone growth is comparable with that of the corresponding toe on the contralateral foot. Therefore, microsurgical toe-to-hand transfers may provide children with extra digits that maintain growth and improve hand function.     

A case of symbrachydactyly with oligodactyly

The term symbrachydactyly describes syndactyly accompanied by brachydactyly. Brachydactyly is seen in middle phalanges of both hands and feet and very short in length or absent. As for syndactyly it is a cutaneous type. It has always been observed unilaterally and sporadically. A familial type of this syndrome has also been reported. There have been many classifications of symbrachydactyly. Of these, Blauth classification is the most favored one. Yet these classifications have been inadequate to include many recently discovered other forms of symbrachydactyly. A three month old child was brought to the Istanbul University Genetic Research Center because of his abnormal hands and feet. He was the second child of a couple who had no kinship ties to each other. In the history of the family, there was no mention of any anomaly as such. There was a complete syndactyly involving the 3rd through the 5th fingers, partial syndactyly between the 2nd and 3rd, and the thumb was normal in the right hand. There was only one finger in the left hand. There was total syndactyly in four toes of the right foot with oligodactyly and absence of the big toe. The left foot had five toes with a complete syndactyly between the 2nd and the 3rd. Radiological observation indicated that the middle phalanges of both extremities were rudimentary or never developed. There was no osseous syndactyly. As observed in this case, oligodactylous type that is bilateral and involves both hands and feet together is very unusual. The purpose of this study is to present a rare case of this anomaly that requires a reassessment of symbrachydactyly and its traditional classifications.     

Immediate toe-to-hand transfer in acute hand injuries: overall results, compared with results for elective cases

In the past 5 years, 25 mutilated digits were reconstructed with immediate toe-to-hand transfers after acute hand injuries, for 21 patients. The overall results of the immediate toe-to-hand transfers were evaluated and compared with the results of 65 elective procedures performed during the same period by the same surgeon. There were 15 cases of great toe-to-hand transfer for thumb reconstruction, two cases of second toe transfer for index finger reconstruction, and four cases of simultaneous two-toe transfer for reconstruction of multiple-digit amputations. Two cases (two of 25 cases, 8 percent) were successfully salvaged with emergency reexploration. The incidences of emergency reexploration and postoperative infection were not significantly different from those for elective toe-to-hand transfer cases. The duration of industrial insurance coverage was much shorter than for elective cases, averaging 225 days (p < 0.001). Approximately 44 percent of the patients maintained their original jobs after immediate toe-to-hand transfer. The subjective satisfaction self-assessment scores of aesthetic appearance and function for the newly reconstructed thumb averaged 80 and 88 (of a total score of 100), respectively. Although satisfaction was lower than for elective reconstruction (p < 0.001), it was higher than for reconstruction of other digits. The donor-site appearance after great toe harvesting was mostly unsatisfactory. Immediate toe-to-hand transfer provides many advantages over the elective procedure in acute hand injuries, including single-stage reconstruction, shortened convalescence, early return to work, and socioeconomic efficiency. Because there were no significant differences in the success rates, frequencies of complications, or ultimate functional results, immediate toe-to-hand transfer is a safe and reliable procedure that is indicated for specific cases of acute digital amputation.     

Fingertip reconstructions using partial-toe transfers

Fifty-six partial toes were transferred to reconstruct fingertip deficits. The transfers from the big toe mainly consisted of 3 trimmed big toetips, 3 vascularized nail grafts, 3 onychocutaneous flaps, 19 thin osteo-onychocutaneous flaps, and 2 hemipulp flaps. The transfers from the second toe mainly consisted of 8 trimmed second toetips, 5 reduced second toes, and 9 whole distal phalanges. The average values of postoperative sensory recovery of the osteo-onychocutaneous flaps including the vascularized nail grafts were 3.1 (Semmes-Weinstein test) and 6.3 mm (moving two-point discrimination) at 2.6 years after the transfer; those of the thin osteo-onychocutaneous flaps were 3.1 and 7.2 mm at 2.0 years after surgery; those of the trimmed big toe tip transfers were 3.61 and 6.5 mm at 1.8 years after surgery; and those of the trimmed second toetip transfers were 3.37 and 6.3 mm at 2.6 years after transfer. Those of the distal phalanx of the second toe were 3.41 and 7.9 mm at 1.2 years after surgery, and those of the reduced second toe were 3.2 and 6.7 mm at 10.6 months after surgery.     

Reverse anterior tibial artery flap for reconstruction of foot donor site

The foot offers numerous useful options for hand reconstruction. Hallux transfer, dorsalis pedis flap, second toe transfers, and toe joint transfers offer good functional results in reconstructed hands. However, when the donor site is repaired with skin grafts, delayed wound healing, scarring, and contractures often result. Poor cosmesis of the donor site and altered gait are the main drawbacks of the procedures. The authors propose a new concept of primary reconstruction of the donor foot using a reverse-flow anterior tibial flap from the same leg. Two flaps are raised from the same anterior tibial vessel system in continuity as a distal free flap for hand reconstruction and as a proximal reverse-flow pedicled flap to resurface the donor defect. This technique allows good flap reconstruction of the foot donor site, reducing morbidity and limiting the operation to the same limb. The authors report their experience of 33 cases. There were no failures. Primary wound healing was achieved in the foot donor site, with acceptable cosmesis and satisfactory function.     

Barium swallows after free jejunal transfer: should they be performed routinely?

Fistula formation after free jejunal transfer for pharyngoesophageal reconstruction is a serious complication with potentially critical consequences. Barium swallow is used postoperatively to check for anastomotic competence before feeding but has been unreliable as a predictor of leak at our institution. The objective of this study was to evaluate the role of routine postoperative barium swallow in 41 consecutive jejunal transfers. Thirty-nine patients who underwent 41 consecutive free jejunal transfers had a routine barium swallow performed between postoperative days 12 and 17. Radiologic findings and clinical outcome were evaluated and correlated. All barium swallows were reviewed by a single experienced radiologist in a blinded fashion. One total and one partial flap failure necessitated a second free jejunal transfer. Pharyngocutaneous fistulae developed after nine free jejunal transfers, of which the barium swallow was normal in four (44 percent) and showed a leak in five (56 percent). In the 32 free jejunal transfers with no clinical leaks, 6 (19 percent) had radiologic leakage of contrast. Thus, barium swallow was normal in 30 patients and showed leakage in 11 patients. Normal barium swallow correlated with uncomplicated clinical course in 26 of 30 cases. In the remaining four cases (13 percent), however, a delayed fistula developed, which was secondary to flap necrosis in one case (negative predictive value 87 percent). On the other hand, radiologic leaks corroborated clinical fistula in 5 of 11 cases (45 percent), whereas no fistula developed in 6 cases (positive predictive value 46 percent). Of the five patients with clinical fistulae, four had early leaks (within 1 week), and the barium swallow did not provide additional information. The fifth patient developed a delayed leak 2 weeks after the barium swallow. Review of these barium swallows at the time of this study reversed the initial report of leakage in three patients, improving the predictive value to 63 percent. These patients had an uncomplicated clinical course. The positive predictive value of clinical assessment alone was 63 percent. We conclude that barium studies following free jejunal transfers can be difficult to interpret, but an experienced radiologist can improve their accuracy. A normal barium swallow, however, does not ensure an uneventful clinical course. Similarly, radiologic leaks do not imply a clinical complication of fistula. Clinical judgment should therefore be exercised in initiating oral intake after free jejunal transfer. Barium swallow should be used only as an adjunct to aid in patient management.     

Minimizing impairment in laborers with finger losses distal to the proximal interphalangeal joint by second toe transfer

Traditionally, toe-to-hand transfers have been reserved for thumb amputations or for use after severe mutilating injuries. The authors report their experience with the use of second toe-for-finger amputations with preserved or reconstructible proximal interphalangeal joints in manual workers. The aim of the procedure was to reduce impairment and to upgrade the hand from a functional and cosmetic standpoint. Fifteen second-toe wrap-around or variations were carried out on 11 adults (18 to 41 years old). Four patients with two or more finger amputations received two sequential second toes; four patients with two finger amputations received one toe; and each of three patients with single-digit amputation received a single toe. All but one amputation were performed less than 3 weeks after the accident. All toes survived. Range of motion at the native proximal interphalangeal joint was more than 90 percent in all patients but one; however, it was minimal at the transplanted joints. Patient satisfaction was high from a cosmetic and functional standpoint. Ten of 11 laborers resumed their previous activity. On the basis of this experience, a classification with aesthetic and functional implications is proposed to help in the decision-making process when dealing with multidigital injuries. It is concluded that second-toe transfer is an excellent choice for finger amputation distal to the proximal interphalangeal joint in laborers. Its prime indication is for amputations of two fingers where at least one toe should be transferred, as required, to achieve an "acceptable hand" (three-fingered hand). Early transfer allows salvage of critical structures from the damaged finger, such as joints, tendons, and bone, that otherwise would be lost. Early transplantation is highly recommended.     

Food Transfer and Development of Feeding Behavior and Food-Associated Vocalizations in Cotton-Top Tamarins

Food transfer between adults and infants is common in many marmoset and tamarin monkeys, and is often accompanied by vocalizations. We hypothesized that vocalizations by adults in a food transfer context creates an opportunity for infants to learn not only what foods are appropriate but what vocalizations are appropriate in feeding contexts. We studied the development of feeding behavior and food-associated vocalizations in 10 infant cotton-top tamarins through the first 20 wks of life. Infants obtained solid food through transfers from older group members, primarily the adult male, beginning at weeks 5–6. Both adults and infants vocalized during food transfers with adults, producing rapid sequences of the call types adults normally give when feeding. Infants were usually successful in obtaining food primarily when the adult was vocalizing. The sooner infants were active participants in food transfers, the sooner they began to feed independently. In the early weeks, infants produced a large number of vocal types during food transfers, but with increasing age there was a steady increase in the number of adult-form food calls and a reduction in other, non-food-associated calls. Infants that fed independently at an early age produced fewer non-food-associated calls by the last month of observation. Infants called at higher rates to their most preferred food. Food transfers accompanied by vocalizations may provide an opportunity for infants to learn about appropriate foods as well as the vocalizations that accompany feeding in adults, and may represent a form of 'coaching' or information donation by adults.     

Reconstruction of the cervical esophagus: free jejunal transfer versus gastric pull-up

Use of enteric grafts is a popular method for reconstruction of the cervical esophagus and hypopharynx. Free jejunal transfer (FJT) and gastric pull-up (GP) are the most popular methods used. This discussion is a retrospective review of our experience with 50 cases of free jejunal transfer and 15 cases of gastric pull-up. The graft survival rate was 94 percent (47 of 50) for free jejunal transfer and 87 percent (13 of 15) for gastric pull-up. Successful swallowing was achieved in 88 percent (44 of 50) of free jejunal transfers and 87 percent (13 of 15) of gastric pull-ups. Patients with free jejunal transfers were able to swallow and leave the hospital sooner: 10.6 versus 16.0 days and 22.3 versus 29.0 days, respectively. Fistulas occurred in 16 percent (8 of 50) of free jejunal transfers, most of which (6 of 8) healed spontaneously. Fistulas occurred in 20 percent (3 of 15) of gastric pull-ups, only one of which healed spontaneously. Stricture was the most common late complication for free jejunal transfers, 22 percent (11 of 50), whereas reflux was most common in gastric pull-ups, 20 percent (3 of 15). In patients with advanced cancer, extensive esophageal resection into the chest is often required, and gastric pull-up seems to be an easier and more direct form of reconstruction. In limited resection of the hypopharynx and esophagus, especially with proximal lesions, free jejunal transfer is simpler and avoids mediastinal dissection. This concept as well as other advantages and disadvantages of both techniques will be discussed.     

Correction of pincer-nail deformity using dermal grafting

Pincer-nail syndrome has been described as distortion in the shape of the nails with excessive transverse curvature of the plate that increases from proximal to distal, leading to pinching and loss of soft tissue in the affected digit, resulting in severe pain. Many treatments have been recommended, but an effective long-term method that preserves the nail matrix has not been described. A method of dermal grafting under the nail matrix is described, and the results of treatment of six digits are reported. Five women and one man with an average age of 52 were treated. The affected digit was the thumb in four patients and the great toe in two patients. Follow-up averaged 25 1/2 months. The results were good in all cases with only one side of one nail remaining slightly curved. Pain was relieved in all cases, and complete adherence of the new nail plate occurred. Dermal grafting seems to provide excellent long-term treatment of the pincer-nail deformity with preservation of the nail matrix.     

Classification for congenital anomalies of the hand: the IFSSH classification and the JSSH modification

The purpose of a classification for clinical problems which, except for a few specialized centers, occur only sporadically is to provide a system where these cases can be stored. This should allow all involved investigators to speak the same language; so-doing syndromes can be delinated, frequencies of occurence established and results of--different--treatments compared. A classification system should be simple to use, reliable and uniformly accepted. It should allow space for adaptations and/or extensions. The IFSSH proposed a 7 categories classification based on the proposed classification of Swanson et al. in 1976. This classification, was based on, which was thought in the seventies, etiopathogenic pathways. These 7 groups are: I. Failure of formation; transverse (A), or longitudinal (B) II. Failure of differentiation III. Polydactyly IV. Overgrowth V. Undergrowth VI. Amniotic band syndrome VII. Generalized skeletal syndromes. The extended classification proposed by IFSSH was used to classify 1013 hand differences in 925 hands of 650 patients. We found associated anomalies in 26.7%. The classification was straightforward in 86%, difficult in 6.6% and not possible in 7.8%. Group II was the most numerous group including 513 anomalies. We propose to include in this group the Madelung deformity, the Kirner deformity and congenital trigger fingers and trigger thumbs. In group I the radial and ulnar deficiencies, limited to the hand without forearm deficlencies should be Included. Triphalangeal thumbs are a problem, we suggest it to be listed in group III and consider it as a duplication in length. It is not always possible to evaluate the (transverse) absence of the fingers or hand. Longitudinal deficiencies (group IIB), symbrachydactyly (group V), and amniotic bands (group IV) occasionally develop a phenotype similar to the genuine transverse deficiency (group IA). Recently, the Japanese Society for Surgery of the Hand (JSSH) (16) proposed an extension/modification of the IFSSH classification. Based on newer knowledge on teratology, symbrachydactyly in all stages were transfered to group I. Two new groups were introduced. A group "failure of finger ray induction" including typical cleft hand (IC), central polydactyly (III) and (bony) syndactyly (II)--was included. Also a group of "unclassifiable" cases was added. This Japanese proposed classification is a real improvement and most clinicians and surgeons tend to use it in the future.     

Experiments on egg transfer in the cow and ewe: dependence of conception rate on the transfer procedure and stage of the oestrous cycle.

The effects on embryo survival of procedures used in transferring eggs non-surgically were investigated in three experiments in ewes and heifers. In Exp. 1, two techniques for introducing eggs into the uterus through the cervix in heifers were compared; namely (i) deposition of the eggs high into the uterine horn or (ii) into the body of the uterus. Both methods were followed by inflation of the uterus with carbon dioxide. Out of a total of 34 heifers, only one became pregnant by the use of Method (i). Non-surgical egg tansfers early (Days 3 to 5) or later (Days 6 to 9) in the oestrous cycles of heifers were carried out in Exp. 2. Three transfer procedures were compared: (i) pipette transfer of an egg into the body of the uterus through the cervix (control), (ii) the control procedure performed under Fluothane anaesthesia, or (iii) followed by inflation of the uterus with carbon dioxide. Wide transfers carried out early in the cycle, pregnancies resulted in 1/10, 0/10 and 1/10 of the heifers in the control, carbon dioxide and Fluothane groups, respectively. With late transfers, 7/20, 1/10 and 8/20 heifers became pregnant in the respective treatment groups. This trend for pregnancy rate to be improved when late transfers were done in the control and Fluothane groups was significant only at the 10% level of probability when both groups were pooled. It was tentatively concluded, however, that non-surgical transfers of fertilized eggs to heifers may be best done during mid-cycle, after Day 6. Fluothane anaesthesia did not improve conception rate. Inflation of the uterus with carbon dioxide appeared to be deleterious when used at the mid-cycle stage in heifers. In Exp. 3, it was found that inflation of the ewe's uterus with carbon dioxide or nitrogen following the surgical thansfer of an egg did not affect the incidence of pregnancy. The introduction of 50 mul liquid Fluothane into the lumen of the uterus was embryotoxic.     

Suitability of the scapular flap for reconstructions of the foot

Eighteen patients with mainly a traumatic soft-tissue defect of the foot underwent reconstruction with a microvascular free scapular flap. Of the 17 successful transfers, 13 were to the weight-bearing parts of the foot. The stability and contour of the flaps were assessed after an average follow-up time of 3 years (range 1 to 5 years). The thicknesses of the scapular donor site and flap and the recipient site were measured by an ultrasound technique. The resistance of the flap to shear was measured with a dynamometer. The ultrasound measurements aided in refining our operative technique. In early cases, the flap thickness after transfer could be more than double what it was in the donor area. With proper tightening, the thickness could be reduced, with improvement in contour but no increase in soft-tissue stability or shear resistance of the flap. Without proper tightening, the scapular flap tended to be redundant when transferred to the foot. For good results, the patient should be lean, since the optimal thickness of the scapular donor site was less than 6 mm and the maximum thickness should not exceed 8 to 10 mm. The differences in shear resistance between the flaps were not associated with the soft-tissue stability of the reconstruction. The relative laxity of the flap on the plantar surface was found by several patients to be subjectively unpleasant. Although good contour could be achieved when covering the plantar heel, the tendency of the flap to develop abrasions and superficial breakdowns made it unsatisfactory for covering this area.(ABSTRACT TRUNCATED AT 250 WORDS)     

Simultaneous multiple toe transfers in hand reconstruction

Our experience with simultaneous transfer of two or more toe units to the same hand where multiple digits were missing is presented. Forty-six toes from 38 feet were transferred to reconstruct 19 hands in 19 patients. The transfers consisted of 7 combined second and third toe units and 32 single toes. Three patients had a primary and 16 patients had a secondary reconstruction. There was one complete and one partial failure. The two-point discrimination ranged from 6 mm to protective sensation. Total active movement averaged 57 degrees in the thumb and 127, 93, 71, and 68 degrees, respectively, in the fingers reconstructed at middle phalanx, proximal phalanx, metacarpophalangeal joint, and metacarpal head. Pulp-to-pulp pinch averaged 2.4 kg in patients who had thumbs reconstructed and averaged 3.0 kg in patients who had normal thumbs. There was no cold intolerance, and no significantly disabled foot occurred except one with scissoring deformity. Simultaneous multiple toe transfer in hand reconstruction is feasible without increased complications both in primary and secondary wound conditions. It is time-effective and cost-effective.     

Treatment of lateral ray polydactyly of the foot: focusing on the selection of the toe to be excised

The purposes of this study were to evaluate the results of the operative treatment of lateral ray polydactyly and to consider appropriate surgical procedures, especially focusing on the selection of the toe, lateral toe or medial toe, to be resected. Twenty-two patients with lateral ray polydactyly foot (25 individual feet) at an average of 71 months' follow-up were included in this study. Cases were classified morphologically into three types on the basis of Hirase's configuration. In addition, these types were divided into two subtypes, metatarsal and phalangeal, on the basis of radiographic evaluation of the level of duplication. The clinical evaluations of the reconstructed toe were performed, and these results were investigated according to their morphologic classification and excised toe group. The distinctive problem of medial toe excision is valgus deformity. Eight of 25 toes retained persistent valgus deformity, and all of these cases were in the medial toe excision group. On the other hand, a distinctive problem in lateral toe excision is postoperative pain. Two patients suffered from postoperative pain in phalangeal type cases in the lateral toe excision group, and the remaining medial toe had a medial protuberant middle phalanx. The pain occurred at that protuberant point. Based on their experiences, the authors created an algorithm for selection of the toe to be excised. In metatarsal type cases, from a functional perspective, the toe that has a radiographically dominant metatarsus should be retained. On the other hand, in phalangeal type cases, the authors give priority to shape rather than function, and they excise the morphologically smaller toe independent of the condition of the phalanx as viewed on radiography. If the medial toe and the lateral toe are approximately the same size, the authors excise the lateral toe to avoid valgus deformity. When the lateral toe has severe valgus deformity that seems unlikely to be correctable intraoperatively, the lateral toe should be considered for excision even if it is larger than the medial toe.     

Congenital curved nail of the fourth toe

Five cases of congenital curved nail of the fourth toe are reported. Patients included four males and one female; four cases were bilateral, and one was unilateral. There were no other significant associated anomalies of the extremities, and only the fourth toes were affected. The features of the deformity are a curved nail and hypoplasia of the soft tissue and bone of the distal phalanx of the fourth toe. This anomaly may be transmitted autosomally and is unique in that it may be of mesodermic origin.     

The outcome of failed free flaps in head and neck and extremity reconstruction: what is next in the reconstructive ladder?

The indications for free flaps have been more or less clarified; however, the course of reconstruction after the failure of a free flap remains undetermined. Is it better to insist on one's initial choice, or should surgeons downgrade their reconstructive goals? To establish a preliminary guideline, this study was designed to retrospectively analyze the outcome of failed free-tissue transfers performed in the authors hospital. Over the past 8 years (1990 through 1997), 3361 head and neck and extremity reconstructions were performed by free-tissue transfers, excluding toe transplantations. Among these reconstructions, 1235 flaps (36.7 percent) were transferred to the head and neck region, and 2126 flaps (63.3 percent) to the extremities. A total of 101 failures (3.0 percent total plus the partial failure rate) were encountered. Forty-two failures occurred in the head and neck region, and 59 in the extremities. Evaluation of the cases revealed that one of three following approaches to handling the failure was taken: (1) a second free-tissue transfer; (2) a regional flap transfer; or (3) conservative management with debridement, wound care, and subsequent closure by secondary intention, whether by local flaps or skin grafting. In the head and neck region, 17 second free flaps (40 percent) and 15 regional flaps (36 percent) were transferred to salvage the reconstruction, whereas conservative management was undertaken in the remaining 10 cases (24 percent). In the extremities, 37 failures were treated conservatively (63 percent) in addition to 17 second free flaps (29 percent) and three regional flaps (5 percent) used to salvage the failed reconstruction. Two cases underwent amputation (3 percent). The average time elapsed between the failure and second free-tissue transfer was 12 days (range, 2 to 60 days) in the head and neck region and 18 days (range, 2 to 56 days) in the extremities. In a total of 34 second free-tissue transfers at both localizations, there were only three failures (9 percent). However, in the head and neck region, seven of the regional flaps transferred (47 percent) and four cases that were conservatively treated (40 percent) either failed or developed complications that lengthened the reconstruction period because of additional procedures. Six other free-tissue transfers had to be performed to manage these complicated cases. Conservative management was quite successful in the extremities; most patients' wounds healed, although more than one skin-graft procedure was required in 10 patients (27 percent). In conclusion, a second free-tissue transfer is, in general, a relatively more reliable and more effective procedure for the treatment of flap failure in the head and neck region, as well as failed vascularized bone flaps in the reconstruction of the extremities. Conservative treatment may be a simple and valid alternative to second (free) flaps for soft-tissue coverage in extremities with partial and even total losses.     

The power of phylogenetic approaches to detect horizontally transferred genes

Background

Horizontal gene transfer plays an important role in evolution because it sometimes allows recipient lineages to adapt to new ecological niches. High genes transfer frequencies were inferred for prokaryotic and early eukaryotic evolution. Does horizontal gene transfer also impact phylogenetic reconstruction of the evolutionary history of genomes and organisms? The answer to this question depends at least in part on the actual gene transfer frequencies and on the ability to weed out transferred genes from further analyses. Are the detected transfers mainly false positives, or are they the tip of an iceberg of many transfer events most of which go undetected by current methods?

Results

Phylogenetic detection methods appear to be the method of choice to infer gene transfers, especially for ancient transfers and those followed by orthologous replacement. Here we explore how well some of these methods perform using in silico transfers between the terminal branches of a gamma proteobacterial, genome based phylogeny. For the experiments performed here on average the AU test at a 5% significance level detects 90.3% of the transfers and 91% of the exchanges as significant. Using the Robinson-Foulds distance only 57.7% of the exchanges and 60% of the donations were identified as significant. Analyses using bipartition spectra appeared most successful in our test case. The power of detection was on average 97% using a 70% cut-off and 94.2% with 90% cut-off for identifying conflicting bipartitions, while the rate of false positives was below 4.2% and 2.1% for the two cut-offs, respectively. For all methods the detection rates improved when more intervening branches separated donor and recipient.

Conclusion

Rates of detected transfers should not be mistaken for the actual transfer rates; most analyses of gene transfers remain anecdotal. The method and significance level to identify potential gene transfer events represent a trade-off between the frequency of erroneous identification (false positives) and the power to detect actual transfer events.

     

Cryopreserved autologous nipple-areola complex transfer to the reconstructed breast

If a patient's nipple-areola complex is available for grafting after mastectomy, it is the best material to use for nipple-areola reconstruction. The authors performed delayed autologous nipple-areola complex transfer to reconstructed breasts in 10 patients (mean age, 47 years; range, 40 to 53 years). The nipple-areola complex was cryopreserved with a programmed freezer after mastectomy. Histological examination of the tissue surrounding the nipple and areola eliminated the possibility of cancer invasion. At the time of transfer, the cryopreserved nipple-areola complex was thawed in 37 degrees C water and grafted on a projection made by a denuded dermal flap on the reconstructed breast. Each patient underwent immediate breast reconstruction using an innervated pedicled transverse rectus abdominis musculocutaneous (TRAM) flap. The patients' postoperative courses were uneventful. The timing of transfer ranged from 3 months to 1 year (mean, 5.8 months) after breast reconstruction. Nipple projection was made by the "four" dermal flap in five cases, a round dermal flap in three cases, a double dermal flap in one case, and a denuded skate flap in one case. The follow-up period ranged from 5 to 36 months (mean, 21.8 months). All grafts were adapted. The final evaluation of nipple-areola complex adaptation was good in four cases, fair in four cases, and poor in two cases. Histological examination of the hematoxylin and eosin stains showed no remarkable destruction of the skin of the nipple and areola, and electron microscopic examination of the areola skin revealed no significant change. However, electron microscopic examination of the nipple skin showed serious damage to skin components, including elongation of the desmosome, widening of the intercellular space at the prickle cell and basal layers, and shrinking of prickle and basal cells. Although further development of the freezing process and cryopreservation technique is needed to prevent depigmentation of the nipple and areola, cryopreserved nipple-areola complex transfer to a reconstructed breast could be an alternative method of nipple-areola reconstruction.