The causes of the nasolabial crease: a histomorphological study.

There are two main conflicting theories on how the nasolabial crease is formed: a muscular theory and a fascial theory. The muscular theory states that the nasolabial crease is mainly formed by the musculodermal insertions of the lip elevator muscles. The fascial theory claims that the nasolabial crease is mainly formed by dense fibrous tissue and by the firm fascial attachments to the fascia of the lip elevator muscles. If the muscular theory was true, the musculodermal insertions of the facial muscles could be interrupted directly by intradermal injections of low doses of botulinum toxin. Eight cadavers who presented with bilateral nasolabial creases were enrolled in the study. The nasolabial creases were harvested from 14 facial halves in their entire lengths and breadths with 5-mm medial and lateral rims. The horizontally cut samples were stained with hematoxylin-eosin (H&E) and Elastica van Gieson (EVG). Immunohistochemistry for the smooth muscle marker actin and the skeletal muscle marker desmin was also performed. In each of the nasolabial creases, numerous skeletal muscle fibers were found in the dermis, which confirmed the muscular theory of the cause of the nasolabial crease. In addition, muscle fibers were present in the dermis 4 mm medial and 4 mm lateral to the nasolabial crease, but the amounts were significantly less than the amount located directly in the crease. Botulinum toxin injected intradermally into the nasolabial crease might constitute a new treatment option to minimize or even eradicate the crease and the fold.

The number of intercostal artery perforators over the distal latissimus dorsi muscle.

With the increasing popularity of perforator flaps as "musculocutaneous flaps without muscle," a new interest in the intercostal vessels as source vessels for perforator flaps has arisen. In a recent study, the branches of the three lowermost intercostal vessels to the latissimus dorsi were studied in detail. Now that these muscular branches are well understood, the present study examines how many of these branches reach the overlying skin as musculocutaneous perforators. We identified the intercostal artery perforators in the ninth, tenth, and eleventh interspaces, in 42 hemithoraces. Only branches that measured 0.5 mm or more in external diameter were included. The course of the perforators was followed from their exit from the latissimus dorsi muscle up to the entrance at the undersurface of the skin. This entrance point was punctured by a pin and thus marked on the skin. This study showed that at least three musculocutaneous perforators were present over the intercostal spaces IX-XI in every dorsal hemithorax (average 8 +/- 3, range 3-16). Potentially, each of these vessels can be used as a pedicle for a separate perforator flap, leaving the more proximal parts of the latissimus dorsi intact for a second flap based on the dominant thoracodorsal vessels.

Prevention of seroma after abdominoplasty.

BACKGROUND: Seroma is one of the most troubling complications after abdominoplasty; incidence rates of up to 25% have been reported. If it is correct that shearing forces between the two separated abdominal layers play a key role in the development of seroma, postoperative immobilization of the patient until the layers are sufficiently adhered may be a solution to the problem. OBJECTIVE: The authors examine the association between length of immobilization and the development of seroma. METHODS: This retrospective study included 60 patients; half were immobilized for 24 hours (group 1) and the other half were immobilized for at least 48 hours (group 2). For thromboembolism prophylaxis, all patients received low molecular weight heparin and compression stockings. Postoperative follow-up for detection of seroma continued for at least three months. RESULTS: Mobilization after 24 hours led to a seroma rate of 13%, whereas immobilization of at least 48 hours decreased the seroma rate to 0%. CONCLUSIONS: For abdominoplasty patients with a low or moderate thromboembolic risk, the data suggest that immobilization for at least 48 hours with chemical and mechanical thromboembolism prophylaxis significantly reduces the risk of seroma.

The normal width of the linea alba in nulliparous women.

The function of the linea alba is to maintain the abdominal muscles at a certain proximity to each other. In the case of long-lasting increased intra-abdominal pressure, the linea alba widens. Yet, as the existence of the linea a priori implicates a physiological distance between the two rectus muscles, the question arises as to what the normal width of the linea alba is. To evaluate the normal width of the linea alba, we examined 150 nulliparous women between 20 and 45 years of age with a body mass index < 30 kg m(-2) by ultrasound at three reference points: the origin at the xiphoid and 3 cm above and 2 cm below the umbilicus. The examination revealed a broad range of widths at the three reference points. The linea was widest at 3 cm above the umbilicus (-35 mm), followed by the reference point 2 cm below the umbilicus (-31 mm) and the origin at the xiphoid (-31 mm). The mean width was 7 +/- 5 mm at the xiphoid and 13 +/- 7 mm above and 8 +/- 6 mm below the umbilicus. For the definition of the normal width of the linea, the 10th and 90th percentiles were taken. The linea alba can be considered "normal" up to a width of 15 mm at the xiphoid, up to 22 mm at the reference point 3 cm above the umbilicus and up to 16 mm at the reference point 2 cm below the umbilicus in nulliparous women.

The interpectoral fascia flap.

Despite the great number of pedicled and free flaps that are available for defect and contour repair, the number of fascia flaps with an axial blood supply are sparse. Such flaps with their gliding function are mandatory, whenever coverage with very thin, well-vascularized tissue is necessary. To the currently established fascia flaps, (the temporoparietal fascia flap, the radial forearm fascia flap, the lateral arm fascia flap, and the serratus anterior fascia flap), we want to add a new fascia flap, the interpectoral fascia flap. We dissected the interpectoral fascia flap from 20 cadavers. In each of the 40 hemichests, the trunk of the thoracoacromial vessels was selectively injected with red polyurethane and the tissue containing the pectoral branches was separated from the overlying pectoralis major muscle and converted into an independent fascia flap. The maximum flap length was 13.5 cm and the maximum breadth was 10.3 cm. The length of the vascular pedicle before entering the flap was 3.9 cm +/- 1.4 cm with a range of 1.5-6.8 cm. Concerning the arc of rotation, all 40 flaps reached the posterior axillary fold, and 29 flaps (73%) reached the mandibular border. This new fascia flap has applications as pedicled and as free flap. The pedicled flap is used in the neck region, in the axillary region and as gliding tissue between the nipple-areola complex and the pectoralis major muscle. The usage of the fascia flap as a free flap has similar characteristics as the other fascia flaps.

Relevance of muscle weight as a functional parameter for the regeneration of the peroneal nerve in rabbits.

To evaluate the relevance of muscle weight as a functional parameter of motor regeneration, the nerve-dependent muscle weights were measured and compared with the toe-spreading reflex and the muscle action potential in different designs of nerve conditioning of the peroneal nerve in New Zealand White rabbits. From 100 peroneal nerves in 50 rabbits, 60 nerves received a conditioning crush lesion and 4 weeks later a test lesion--a transection with suturing at different sites. An additional 10 peroneal nerves were solely transected and sutured, 10 peroneal nerves were sham-operated, and 20 peroneal nerves remained unoperated for control. Eleven weeks after the final lesion, when the toe-spreading reflex had returned, the peroneal muscle weight showed a non-significant relation with the toe-spreading reflex (area 0.650, P = 0.149), whereas the relation of the amplitude (area 0.964, P < 0.001) and the conduction velocity (area 0.721, P = 0.033, left side) with the toe-spreading reflex were significant. Despite the lower sensitivity and specificity of the muscle weight, the possibility to measure the weight of all three peroneal nerve-dependent muscles separately represents a more detailed method of evaluation than both the toe-spreading reflex testing and the muscle action potential recording and justifies its use as a functional parameter in the early phase of peroneal motor regeneration in the rabbit.

Polyurethane elastomer: a new material for the visualization of cadaveric blood vessels.

A multitude of various materials are available for the visualization of cadaveric vessels, ranging from natural materials like gelatin and latex to synthetic materials like silicone rubber or acrylates. To achieve a detailed overview of the vascular architecture in microvascular studies in experimental flap surgery, the injected material should have low viscosity to assure perfusion of even the smallest vessels. In addition, the material ideally should have either no or only minimal shrinkage, and should harden within a reasonable time, but retain sufficient elasticity and resistance to withstand tearing off the delicate vessels during subsequent dissection or casting. Because none of the available injection materials adequately combines these attributes, we evaluated the polyurethane elastomer "PU4ii" in latissimus dorsi muscles as a new material for the visualization of cadaveric vessels in comparison with the frequently used silicone rubber. The dissection of vessels injected with PU4ii proved easy largely because of its exceptional hardness. Even if not visible before dissection, the completely perfused vessels were easily palpated in the surrounding fat or muscle tissue of the microsurgical latissimus dorsi model. Despite the significantly higher hardness of PU4ii over silicone rubber (98 Sh-A vs. 12 Sh-A), PU4ii proved enough elasticity (20-25 N/mm(2) E modulus) and a high tear resistance (64-68 N/mm vs. 15 N/mm) preventing breakage during dissection even within the smallest vessels. In contrast to silicone rubber (and latex or gelatin), the high corrosion resistance and form stability of PU4ii also allowed building of casts for qualitative examination by scanning electron microscopy and quantitative analysis of the vessel density using micro-computed tomography with accurate 3D representation. In this study we show that PU4ii has physical characteristics that make it a multi-purpose material that allows at the same breath an excellent gross visualization of the architecture of cadaveric blood vessels as well as a detailed evaluation of casts by modern microscopic and or radiologic tools. Thus, the new polyurethane elastomer PU4ii is in many respects superior to the widely used silicone rubber and can be strongly recommended as a visualization material for a comprehensive evaluation of cadaveric blood vessels in microsurgery.

The bipedicled and bipartite latissimus dorsi free and perforator flap: an anatomic study.

BACKGROUND: The purpose of this study was to search for an enhanced blood supply in the distal one third of the latissimus dorsi and, thus, to have a closer look at the muscular branches of the intercostal vessels. METHODS: The muscle branches to the latissimus dorsi muscle arising in the "costal groove" segment of the three lowermost intercostal vessels (ninth to eleventh interspaces) were identified bilaterally in 28 fixed hemithoraces (84 interspaces). In the interspaces, the perforators 0.5 mm or greater were localized and dissected free to their junction with the intercostal source vessels. The number of branches was recorded and external diameters of branches and source vessels were measured. RESULTS: At least one big muscular branch to the latissimus dorsi was found in every hemithorax. In the tenth and eleventh interspaces, at least one branch was found in all cases; in the ninth interspaces, one branch was found in 93 percent of cases. A second big branch was found in approximately half of the ninth and tenth interspaces, and in one fourth of the eleventh interspaces. The external mean diameter of the muscular branches at their branching point from the source vessel was 1.5 mm for the artery and 1.8 mm for the vein. CONCLUSIONS: The versatility of the latissimus dorsi muscle can be enhanced by including intercostal vascular branches of the intercostal groove segment into the flap design. The latissimus dorsi can be harvested as a bipedicled free flap; thus, it allows the harvest of two separate bipartite, independent muscle, musculocutaneous, or perforator flaps.

Immunohistochemical differentiation and localization analysis of sweat glands in the adult human axilla.

BACKGROUND: The classic concept of axillary glands differentiates between eccrine glands, producing abundant clear, nonodorous sweat; and apocrine glands, excreting small amounts of turbid, odorous milky sweat. A third type of sweat glands, the "apoeccrine" glands, were recently identified. To define the different types of sweat glands and their location and number, the authors carried out a prospective histologic study on adult human axillary skin, including various immunohistochemical markers. METHODS: Forty-three consecutive Caucasian, subjectively normhidrotic patients, who underwent a surgical procedure in the axilla unrelated to the axillary glands, were included in the study. For verification of normhidrosis, the gravimetric test was carried out by measuring the amount of sweat secretion per minute. Then, a 1 x 1-cm measuring piece of skin and subcutaneous tissue was excised in the apex of the axilla, divided into three samples--altogether, 129 samples--and processed for histologic examination. RESULTS: In the dermis, the authors found only very few eccrine (average, 0.3 gland/cm in only 12 percent of all patients) and apocrine glands (average, 0.1 gland/cm in only 4.7 percent of patients), and no apoeccrine glands in any patient. In the subcutaneous tissue, the mean number of glands per centimeter squared was 10 for the eccrine glands, nine for the apocrine glands, and six for the apoeccrine glands. CONCLUSIONS: In the authors' Caucasian subjects, all or most of the sweat glands were found in the subcutaneous tissue near the border to the dermis and not in the dermis. For extremely hyperfunctioning sweat glands, the authors recommend less radical surgical methods, with the preservation of skin, based on the knowledge that most glands are localized in the subcutaneous tissue.

The thoracoacromial vessels as recipient vessels in microsurgery and supermicrosurgery: an anatomical and sonographic study.

The purpose of this study was to investigate the presence and the precise course of the pectoral branch of the thoracoacromial vessels on the underside of the pectoralis major muscle by anatomical dissection and by color Doppler ultrasound. A further goal was to determine whether these vessels were suitable as recipient vessels in microsurgery and supermicrosurgery for breast reconstruction. In 18 cadavers, the pectoral branch of the thoracoacromial vessels was followed caudally until the diameter of the artery diminished to 1 mm. The same examination was carried out in 40 young female volunteers by tracing the vessel course with color Doppler ultrasound. The 1-mm cutoff point of the artery was measured with reference to the manubrium, the midsternal line, the clavicle, and the upper border of the closest rib. In addition, in the cadavers, the 2-mm cutoff point was determined. At both cutoff points, the diameter of the accompanying vein was measured. The pectoral branch of the thoracoacromial vessels with the artery and concomitant veins could be detected on all 100 undersides of the pectoralis major muscle, anatomically and sonographically. In their course from the acromial region downward, the arteries reached a diameter of 1 mm at an average of 9.9 cm from the manubrium, horizontally 9.4 cm from the midsternal line, and vertically 4.0 cm from the lower border of the clavicle. The 1-mm reference point was situated on the upper border of the third rib in 85 percent of cases. The average distance between the 1-mm and the 2-mm cutoff points was 3.5 cm. At the 1-mm cutoff point, the diameter of the vein was 0.9 mm, and at the 2-mm cutoff point, it was 1.7 mm. Because of their central position at the anterior hemithorax, these vessels are easily accessible from mastectomy incisions, even in skin-sparing mastectomies; the donor-site morbidity is negligible; and as the diameters of the vessels gradually decrease along their caudal course, the recipient site can be chosen precisely according to the length and the diameter of the donor vessels and major mismatch can be avoided. Thus, the pectoral branches of the thoracoacromial vessels are well suited as recipient vessels for (super)microsurgery and are a very promising addendum to the thoracodorsal and internal mammary vessels.

[A body mass index related scale for reconstructive breast reduction]. / Der Body Mass Index als Entscheidungsgrundlage für medizinisch indizierte Brustreduktionen.

PURPOSE: Breast reduction is a highly emotional theme and bears conflicting interest groups: 1) women who are suffering from symptomatic macromastia and therefore would wish to have their breast reduction paid by the insurers, irrespective of the amount of resection weight, 2) the insurance companies, who are ready to cover only really medically indicated operations and due to a lack of objective parameters often apply the very strict, arbitrary criterium for a minimum resection weight of 500 g per breast and 3) the surgeons who try to provide a fair, scientific basis for the differentiation between cosmetic and reconstructive indications for breast reductions for the sake of both the patients and the insurance parties. Concerned about such a generalizing rule we undertook a retrospective review of our patients' charts with both, cosmetic and reconstructive indications to judge the available, more-level minimum resection weight standards and see wether they were appropriate to use, or to provide an objective and measurable guideline for a scaled amount of breast reduction beyond the 500 g-resection-rule, adapted to the individual woman's body proportions. METHODS: 136 women could be included in the study. The resection weight was recorded and correlated to various parameters of the body proportions such as weight, height, the body mass index (BMI) and the body surface. The results were compared to the available minimum resection weight rules. RESULTS: The resection weight ranged from 55 to 1530 g (mean 450 g +/- 266 g, median 406 g). Overweight was present in 36% of all patients, whereas obesity was present in 7.5% of women. The mean BMI was 25.1 kg/m2. Of the twenty-four patients (18%), who were classified a priori as having a cosmetic indication, 4 (18%) had more than 500 g breast tissue resected bilaterally. On the other hand, in 55% of reconstructive patients less than the predicted 500 g of breast tissue had been resected. From all examined parameters the BMI had the highest correlation to the resected mean breast tissue (r = 0.64, p = < 0.001). DISCUSSION: Our retrospective review thus showed that with an arbitrary 500 g breast resection-rule all women beyond the mean values for weight and height were clearly put at a disadvantage. Also not completely solving this problem are the already available, more objective guidelines for graded minimum resection weight recommendations, which have relied on the body weight or the body surface area, parameters that both had a much lower correlation to the resected breast tissue in the patient group than the BMI. We therefore suggest using the BMI as the basis for a graded, more-level weight resection standard for reconstructive breast reductions. This algorithm is related solely to objectifying data and thus avoids biases from empirically derived data or hardly quantifiable breast (or obesity)-related pain syndromes, and respects all the different body builds of women.

The transareolar incision for breast augmentation revisited.

Of the various possible incisions for breast augmentation, the transareolar access has gained only limited popularity. The potential side effects of this incision are said to be altered nipple sensation, impaired lactation, an increased rate of infections with capsular fibrosis, well visible scar formation with hypopigmentation, and the need for an additional access in case a breast ptosis correction should prove necessary at a later date. The purpose of this retrospective study was to judge advantages and limitations of transareolar breast augmentation, and to verify whether the reluctant attitude toward this surgical approach is justified. A sample of 18 patients with a transareolar, retropectoral breast augmentation was selected for a retrospective evaluation. The suitability of the technique in general was examined together with early postoperative complications, sensory changes, and late complications on the basis of an evaluation system for cosmetic surgical results. The study showed that only women with an areolar diameter of 3.5 cm or more without pronounced breast ptosis were suitable for the transareolar access. No early infections were noted. The rate of capsular fibrosis was 11%. Two years after breast augmentation, 16 women (89%) judged their breast sensation to be normal, but objective assessment showed that mean pressure and vibration sensation were moderately compromised in all parts of the breast. The scars were of good quality, with very little hypopigmentation. With appropriate patient selection, respecting the advantages and limitations, the transareolar incision has its definite place among the different incisions for breast augmentation.

[Polyurethane vessels for microvascular surgical training to reduce animal use]. / Training von Mikrogefässanastomosen an Polyurethangefässen zur Reduktion von Tierversuchen.

AIM: Systematic training of the manual skills is inevitable in learning microsurgery. Generally, first exercises are done on two-dimensional models, then the training continues on animals. With the growing ethical awareness, the obligation to protect animals and the stricter animal protection laws, realistic three-dimensional models have become necessary for training of microsurgery. However, the available alternatives all have certain disadvantages. We tested vessels made of polyurethane for microvascular surgical training and compared them to the available three-dimensional synthetic alternatives. DESCRIPTION OF THE TRAINING MODEL: Rose-coloured (arteries) or blue (veins), opaque vessels with a minimal wall thickness of 0.12 mm and a minimal internal diameter of 1 mm are used. To mimic the surgical access and the depth of the operative field, the vessels can be embedded in a synthetic box with or without a cap. The completed anastomosis is checked by injection of a coloured fluid. EXPERIENCES: The consistency and the variable relation of the thickness of the wall to the internal diameter very closely reflect the biological situation. Even training on very fragile venous walls is possible in all manners. After completion of anastomosis the vessels can be opened longitudinally to check the patency of the anastomotic site. DISCUSSION: The described polyurethane vessels are very suitable for microsurgical training as a useful step between the two-dimensional model and the animal. The number of animals required for microsurgical training can clearly be reduced by the use of such synthetic polyurethane vessels.

The cartilage-sparing versus the cartilage-cutting technique: a retrospective quality control comparison of the Francesconi and Converse otoplasties.

From a total of 281 patients with protruding ears who underwent a bilateral otoplasty between 1990 and 2001, a group of 28 (10%) was selected for a retrospective quality control study. The goal was to compare two methods of otoplasty, the Francesconi, a cartilage-sparing technique, and the Converse, a cartilage-cutting technique, in terms of objectively measurable and subjectively discernable differences in results. Objective parameters included measurement of the three cephaloauricular distances and the conchoscapal angle. An independent plastic surgeon performed the evaluation by means of a systematic evaluation system for rating cosmetic surgical procedures and a 5-point visual analog scale for rating satisfaction. The patients' subjective rate of satisfaction also was investigated using the 5-point scale. The mean medial and inferior cephaloauricular distances were significantly smaller in the Francesconi group. The concoscaphal angle was 90 degrees, or less in all the patients of the Francesconi group, but more than 90 degrees in eight patients (57%) of the Converse group (p = 0.041). Accordingly, the independent surgeon found adequate correction of protrusion in 86% of the Francesconi group and 50% of the Converse group (p = 0.050). His satisfaction rate was significantly in favor of the Francesconi technique (p = 0.006). Not unexpectedly, the patients' satisfaction rate was comparably high in both groups, and there was no statistical difference between them. In conclusion, the quality control led to a clear preference of the Francesconi over the Converse otoplasty. In addition, the assessment of the postoperative results with the systematic evaluation system offered an excellent information base by which to judge the results of otoplasty. Consequent use of this evaluation system will lead to progress in the surgical procedure.

Incidence of the superficial fascia and its relevance in skin-sparing mastectomy.

BACKGROUND: With the move away from classical radical mastectomy to ever more skin-sparing procedures, there has been an ongoing discussion about how much skin and subcutaneous tissue should be resected to perform an adequate mastectomy while leaving viable skin flaps. One of the common recommendations is to dissect just superficial to the superficial layer (SL) of the superficial fascia of the breast. This, in turn, has revived the old, unsolved controversy about the existence or absence of the SL, a fascia that reportedly encloses the mammary gland ventrally. In skin-sparing mastectomies (SSM), which combine tumor resection with immediate breast reconstruction, the ideal would be to create skin flaps that are thin enough to remove all breast tissue but at the same time are thick enough to preserve flap circulation. The feasibility of meeting these two goals simultaneously and the possible role and relevance of the SL as a guide to dissection in SSM was examined in this study. METHODS: Sixty-two breast resection specimens from 31 women who underwent breast reduction were examined histologically to determine whether the SL was present, whether breast tissue could be detected within or beyond this SL, the measured distance between the caudal border of the dermis and the SL or the breast tissue, and whether the thickness of the subcutaneous fat layer was correlated with the patients' physical data, such as body weight or body mass index (BMI). RESULTS: The SL was absent in 44% of resection specimens. When the SL was present, 42% of specimens contained several islands of breast tissue within the SL. No breast tissue was found beyond the SL. The minimal distance between the SL and the dermis varied from 0.2 mm to 4.0 mm; the minimal distance between the breast tissue and the dermis was 0.4 mm. In 50% of specimens, the minimal distance between the dermis and the SL or breast tissue was < 1.1 mm. A distance of > or = 5 mm was encountered in only 17% of specimens, and a distance of > or = 10 mm was encountered in only 5% of specimens. No significant correlation between the right and left breast was found with any of the parameters examined. A weak negative correlation was seen between the BMI and the mean thickness of the subcutaneous fat (P = 0.049; correlation coefficient [r] = -0.39; Spearman rank correlation). CONCLUSIONS: Histologic evaluation revealed that the SL is not present in all breasts and, thus, cannot serve as a reliable plane of dissection. Furthermore, if the SL is present microscopically, then it often is too thin and delicate to be detectable macroscopically. Finally, even if the SL is present and visible macroscopically, the distance to the overlying skin is so small in the majority of patients that a dissection superficial to the SL would not leave viable skin flaps in skin-sparing mastectomies.

Comparison of the incidence and predicted risk of early surgical site infections after breast reduction.

In plastic surgery, clean, elective operations such as breast reductions are anticipated to have low risk factors for infections (1.1-2.1%). To further lower or prevent surgical site infections (SSI), the efficacy of a prophylactic administration of anti-microbacterials remains a current controversial issue in plastic surgery. We report here the findings of a retrospective study in which we examined two groups of patients with breast reductions, one of which received a single-shot antimicrobacterial prophylaxis with cefuroxime preoperatively and the other who were given no anti-microbacterials. The aims were to determine the early SSI incidence of both groups, to classify breast reductions with respect to their inherent SSI risk by two widespread, combined risk scores, i.e., the National Nosocomial Infection Surveillance (NNIS) score and the Study on the Efficacy of Nosocomial Infection Control (SENIC) score, and to compare the actual SSI incidence to the predicted risk of the scores. In the divisions of plastic surgery at two hospitals, 153 patients (group I) and 136 patients (group II) could be included in the study in the 4-year period April 1997 to December 2001. Excluded were all patients with unilateral breast reduction or breast reconstruction and patients who were followed up less than 30 days postoperatively. The two groups were comparable with respect to demographic and clinical features such as age and risk factors, and there were no detectable significant intergroup differences in the general perioperative data. According to the NNIS and the SENIC scores, all operations were "clean," and the American Society of Anesthesiologists (ASA) score was < 3 in all patients. Although the mean duration of the operation was significantly different in the two groups (190 min in group I, 160 min in group II; p < 0.001, Mann-Whitney test; 75th percentile at and 4 and 3 h, respectively), it was longer than 2 h in both groups. The incidence of early infections was 3.9% in the first group, compared with 3.6% in the second group (p = 1.0, odds ratio = 1.07, 95% CI = 0.32-3.6). All infections were local and superficial; no general symptoms were noticed. Three patients had to be readmitted and two of these were reoperated. The rate of infections for both groups was higher than generally anticipated for this kind of clean operations and higher than predicted by the NNIS score for medium risk (predicted risk of 2.9%). The reason for this discrepancy is that the NNIS score is an inpatient risk score which does not include a postdischarge SSI surveillance. Using the NNIS definition of SSI we would have had an infection rate of 0% in both groups in our study. According to the SENIC score, breast reductions can be classified also as medium risk of SSI with a predicted risk of 3.9%, which showed a nearly perfect correspondence with the actual SSI incidence in both study groups. The reason for this increased, medium risk is the factor "operation time > 2 h," which is obviously an inherent risk factor in breast reductions. Among the multitude of patient and nonpatient SSI risk factors, in healthy women operation time was the only factor which could be clearly identified.

Functional, electrophysiologic, and morphometric evaluation of nerve regeneration from coaptation on regenerated nerve fibers: experimental study in rabbits.

The importance of a sufficient number of nerve fibers at a proximal coaptation site is indisputable for the successful repair of nerves; however, the quality of nerve fibers required at this site has yet to be defined. The present study deals with the question of whether it is necessary to trim nerves back to unaffected neuronal tissue or whether the coaptation on recently regenerated nerve fibers, commonly believed to produce a poor quality of repair can, in fact, produce adequate nerve regeneration. Twenty New Zealand White rabbits received a standardized crush lesion on the peroneal nerves of both hind legs. Four weeks later, the nerves of the left hind legs (n = 20) were transected 10 mm distal to the previous crush lesion and coapted to the freshly regenerated nerve fibers. For comparison, on 10 right hind legs, the nerves were transected at the site of previous crushing (Group A, superimposition) or 10 mm proximal to the site of crushing on unscathed nerve fibers (Group B). Eleven weeks later, the quality of nerve regeneration was assessed by the toe-spreading reflex, electrophysiologic data, muscle weight, and histomorphologic evaluation. In the animals of Group A, the quality of nerve regeneration following coaptation on the regrown axons did not differ in any of the examined parameters from the quality of nerve fibers outgrown from the site of the superimposed lesion. Both lesions led to a completely functional reinnervation. Also in Group B, nerve action potential recording and histologic data on both sides did not reveal a significant difference between the number and maturation of nerve fibers equidistant from the suture site, shortly before muscle entrance. With this coaptation model, it could be demonstrated in the peroneal nerve of rabbits, that coaptation to recently regenerated nerve fibers leads to a significant functional regeneration.