Predictive Model of Nail Consistency Using Scanning Electron Microscopy with Energy-Dispersive X-Ray

Simple Summary

Scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS) is a useful technique to analyse elemental composition in the nail plate. The dorsal, intermediate, and ventral layers are differentiated by the levels of the elements present in each layer. The level of calcium in the dorsal layer is the main predictive variable in calculating the predictive model of consistency. This model will provide further knowledge of the factors that determine nail consistency in individuals and help health professionals to better understand nail characteristics and objectively determine nail consistency.

Abstract

The nail plate is made up of tightly packed keratin-rich cells. Factors such as the special distribution of the intermediate filaments in each layer (dorsal, intermediate, and ventral), the relative thickness of the layers, and their chemical composition define the characteristics of each nail. The main objective of this study is to determine nail consistency by calculating a predictive model based on elemental composition analysis using scanning electron microscopy. Nail consistency was determined in 57 participants (29 women and 28 men) in two age groups (young people and adults). Elemental composition was analysed in each layer using scanning SEM-EDS, and nail plate thickness was measured by image analysis. A total of 12 elements were detected in nail plates, of which carbon, nitrogen, phosphorus, sulphur, and calcium showed significant differences between layers (p-values ≤ 0.01). The level of calcium in the dorsal layer was the main predictive variable in calculating the predictive model of consistency, with 75.4% correctly classified cases. Elemental analysis in each layer of the nail plate by SEM-EDS can be used to develop a predictive model of nail consistency that will help health professionals to objectively determine nail consistency.

Treatment and management strategies of onychomycosis

Onychomycosis is one of the most prevalent and severe nail fungal infections, which is affecting a wide population across the globe. It leads to variations like nail thickening, disintegration and hardening. Oral and topical drug delivery systems are the most desirable in treating onychomycosis, but the efficacy of the results is low, resulting in a relapse rate of 25-30%. Due to systemic toxicity and various other disadvantages associated with oral therapy like gastrointestinal, hepatotoxicity, topical therapy is commonly used. Topical therapy improves patient compliance and reduces the cost of treatment. However, due to poor penetration of topical therapy across the nail plate, research is focused on different chemical, mechanical and physical methods to improve drug delivery. Penetration enhancers like Thioglycolic acid, Hydroxypropyl-β-cyclodextrin (HP-β-CD), Sodium lauryl sulfate (SLS), carbocysteine, N-acetylcysteine etc. have shown results enhancing the drug penetration across the nail plate. Results with physical techniques such as iontophoresis, laser and Photodynamic therapy are quite promising, but the long-term suitability of these devices is in need to be determined. In this article, a brief analysis of the treatment procedures, factors affecting drug permeation across nail plate, chemical, mechanical and physical devices used to increase the drug delivery through nails for the onychomycosis management has been achieved.

Anatomic and Histological Features of the Extensor Digitorum Longus Tendon Insertion in the Proximal Nail Matrix of the Second Toe

Background: Anatomic and histological landmarks of the extensor digitorum longus (EDL) tendon insertion in the proximal nail matrix may be key aspects during surgery exposure in order to avoid permanent nail deformities. Objective: The main purpose was to determine the anatomic and histological features of the EDL’s insertion to the proximal nail matrix of the second toe. Methods: A sample of fifty second toes from fresh-frozen human cadavers was included in this study. Using X25-magnification, the proximal nail matrix limits and distal EDL tendon bony insertions were anatomically and histologically detailed. Results: The second toes’ EDLs were deeply located with respect to the nail matrix and extended superficially and dorsally to the distal phalanx in all human cadavers. The second toe distal nail matrix was not attached to the dorsal part of the distal phalanx base periosteum. Conclusions: The EDL is located plantar and directly underneath to the proximal nail matrix as well as dorsally to the bone. The proximal edge of the nail matrix and bed in human cadaver second toes are placed dorsally and overlap the distal EDL insertion. These anatomic and histological features should be used as reference landmarks during digital surgery and invasive procedures.

Resident and Nonresident Fingernail Isotopes Reveal Diet and Travel Patterns,

Global travel has increased, and having a diagnostic tool to distinguish residents from visitors would be valuable. This study examined stable isotope biomarkers of fingernail tissues of resident (n = 26) and nonresident (n = 22) participants in Salt Lake City (SLC), UT, from 2015 to 2016. The purpose of this research was to determine whether fingernail isotopes could be used for reconstructing geolocation movements and to examine the convergence in nonresident fingernail isotopes to that of the resident signal following their arrival to SLC. Resident isotope values defined a baseline to make comparisons to. Initial nonresident hydrogen and oxygen isotope values were correlated with precipitation isotopes of their prior location. Fingernail isotope turnover rates were rapid and nonresident isotopes were indistinguishable from residents after ~71-90 days. The results of our study highlight the utility of stable isotope measurements of fingernail clippings to examine travel history reconstruction that could aid in identification of human remains.

Understanding the formidable nail barrier: A review of the nail microstructure, composition and diseases

The topical treatment of nail fungal infections has been a focal point of nail research in the past few decades as it offers a much safer and focused alternative to conventional oral therapy. Although the current focus remains on exploring the ways of enhancing permeation through the formidable nail barrier, the understanding of the nail microstructure and composition is far from complete. This article reviews our current understanding of the nail microstructure, composition and diseases. A few of the parameters affecting the nail permeability and potential causes of the recurrence of fungal nail infection are also discussed.

A method to determine integrated steroid levels in wildlife claws

Glucocorticoids act throughout life to regulate numerous physiological and behavioral processes. Their levels are therefore highly labile, reacting to varying conditions and stressors. Hence, measuring glucocorticoids (and other steroids) in wildlife is challenging, and devising methods that are unaffected by the stress of capture and handling should be explored. Here we use the tip of free-ranging chameleons' claws that were cut to allow individual identification, and report a steroids extraction and quantification method. Claw steroids present an integrated level representing the period of claw growth. We found that we could measure corticosterone in small amounts of chameleon claw matrix using commercial EIA kits. Using this method, we learned that in wild male chameleons, claw corticosterone levels were associated with body size. We suggest that claw-testing can potentially provide an ideal matrix for wildlife biomonitoring.

Anatomic relationship of the proximal nail matrix to the extensor hallucis longus tendon insertion

BACKGROUND

The purpose of this study was to delineate the relationship of the terminal extensor hallucis longus tendon insertion to the proximal limit of the nail matrix of the great toe.

MATERIAL AND METHODS

Fifty fresh-frozen human cadaver great toes with no evidence of trauma (average age, 62.5 years; 29 males and 21 females) were used for this study. Under 25X magnification, the proximal limit of the nail matrix and the terminal bony insertion of the extensor hallucis longus tendons were identified. The distance from the terminal tendon insertion to the nail matrix was ascertained using precision calipers, an optical microscope, and autocad(®) software for windows. Twenty-five great toes were placed in a neutral formalin solution and further analysed by histological longitudinal-sections. The specimens were stained with haematoxylin and eosin and examined microscopically to determine the presence of the extensor hallucis longus tendon along the dorsal aspect of the distal phalanx of each great toe.

RESULTS

The main result we found in great toes was that the extensor tendon is between the matrix and the phalanx and extends dorsally to the distal aspect of the distal phalanx in all, 100%, specimens. The nail matrix of the great toe is not attached to the periosteum of the dorsal aspect of the base of the distal phalanx as is the case for fingers, because the extensor hallucis tendon is plantar or directly underneath the nail matrix and the tendon is dorsal to the bone.

CONCLUSIONS

We have found that the extensor tendon is between the matrix and the phalanx and extends dorsally to the distal aspect of the distal phalanx. The nail matrix of the great toe is not attached to the periosteum of the dorsal aspect of the base of distal phalanx as is the case in fingers, because the extensor hallucis tendon is plantar or directly underneath the nail matrix and the tendon is dorsal to the bone. Our anatomic study demonstrates that the proximal limit of the matrix and nail bed of the human great toe are dorsal and overlapping the terminal extensor hallucis longus tendon until its distal bony insertion in all specimens.

Insights into drug delivery across the nail plate barrier

Topical therapy is at the forefront in treating nail ailments (especially onychomycosis and nail psoriasis) due to its local effects, which circumvents systemic adverse events, improves patient compliance and reduces treatment cost. However, the success of topical therapy has been hindered due to poor penetration of topical therapeutics across densely keratinized nail plate barrier. For effective topical therapy across nail plate, ungual drug permeation must be enhanced. Present review is designed to provide an insight into prime aspects of transungual drug delivery viz. nail structure and physiology, various onychopathies, techniques of nail permeation enhancement and in vitro models for trans-nail drug permeation studies. Updated list of drug molecules studied across the nail plate and key commercial products have been furnished with sufficient depth. Patents pertinent to, and current clinical status of transungual drug delivery have also been comprehensively reviewed. This is the first systematic critique encompassing the detailed aspects of transungual drug delivery. In our opinion, transungual drug delivery is a promising avenue for researchers to develop novel formulations, augmenting pharmaceutical industries to commercialize the products for nail disorders.

Tangential excision of pigmented nail matrix lesions responsible for longitudinal melanonychia: evaluation of the technique on a series of 30 patients

OBJECTIVES

We sought to assess the shave biopsy technique, which is a new surgical procedure for complete removal of longitudinal melanonychia. We evaluated the quality of the specimen submitted for pathological examination, assessed the postoperative outcome, and ascertained its indication between the other types of matrix biopsies.

DESIGN

This was a retrospective study performed at the dermatologic departments of the Universities of Liège and Brussels, Belgium, of 30 patients with longitudinal or total melanonychia.

RESULTS

Pathological diagnosis was made in all cases; 23 patients were followed up during a period of 6 to 40 months. Seventeen patients had no postoperative nail plate dystrophy (74%) but 16 patients had recurrence of pigmentation (70%).

LIMITATIONS

This was a retrospective study.

CONCLUSIONS

Shave biopsy is an effective technique for dealing with nail matrix lesions that cause longitudinal melanonychia over 4 mm wide. Recurrence of pigmentation is the main drawback of the procedure.

Longitudinal erythronychia: suggestions for evaluation and management

Longitudinal erythronychia is a frequent nail presentation with a limited differential diagnosis. This clinical entity may be divided into cases that involve one (localized) or multiple (polydactylous) nails. The different presentations have distinct differential diagnoses and workups yet often share a common pathogenesis. Localized longitudinal erythronychia most commonly represents onychopapilloma, yet malignancies may present identically. Therefore biopsy may be required. Polydactylous longitudinal erythronychia usually coincides with a regional or systemic cause. Occasionally, it may herald an important underlying disease. A thorough understanding of the pathogenesis, clinical presentations, and possible diagnoses is necessary for successful evaluation and management.

Nail biology and nail science

The nail plate is the permanent product of the nail matrix. Its normal appearance and growth depend on the integrity of several components: the surrounding tissues or perionychium and the bony phalanx that are contributing to the nail apparatus or nail unit. The nail is inserted proximally in an invagination practically parallel to the upper surface of the skin and laterally in the lateral nail grooves. This pocket-like invagination has a roof, the proximal nail fold and a floor, the matrix from which the nail is derived. The germinal matrix forms the bulk of the nail plate. The proximal element forms the superficial third of the nail whereas the distal element provides its inferior two-thirds. The ventral surface of the proximal nail fold adheres closely to the nail for a short distance and forms a gradually desquamating tissue, the cuticle, made of the stratum corneum of both the dorsal and the ventral side of the proximal nail fold. The cuticle seals and therefore protects the ungual cul-de-sac. The nail plate is bordered by the proximal nail fold which is continuous with the similarly structured lateral nail fold on each side. The nail bed extends from the lunula to the hyponychium. It presents with parallel longitudinal rete ridges. This area, by contrast to the matrix has a firm attachment to the nail plate and nail avulsion produces a denudation of the nail bed. Colourless, but translucent, the highly vascular connective tissue containing glomus organs transmits a pink colour through the nail. Among its multiple functions, the nail provides counterpressure to the pulp that is essential to the tactile sensation involving the fingers and to the prevention of the hypertrophy of the distal wall tissue, produced after nail loss of the great toe nail.

In vivo transungual iontophoresis: effect of DC current application on ionic transport and on transonychial water loss

The potential use of iontophoresis to improve drug penetration into the nail has been suggested. However, there is little information concerning transungual iontophoresis in vivo. This work describes the application of transungual iontophoresis to six healthy human volunteers in order to investigate key issues such as the effect of current application on ionic transport and on transonychial water loss (TOWL), and the magnitude of the voltages required for a practical use of the technique. Each volunteer participated in three experiments: passive control, 0.2 mA anodal transungual iontophoresis and 0.2 mA cathodal transungual iontophoresis. A commercial electrode on a skin site was used to complete the electrical circuit. The outward transungual extraction of sodium and chloride ions by passive diffusion and iontophoresis was quantified. Iontophoresis enhanced chloride and sodium transport approximately 8 and 27 fold respectively compared to passive diffusion. Sodium transport numbers were measured to be t(Na+)=0.51+/-0.11. TOWL was used as a potential marker of nail damage and hydration. Basal TOWL was measured before each experiment, and the return to baseline values was monitored for 1h after the treatment (passive or iontophoresis application) was finished. TOWL was increased after both iontophoretic and passive experiments and typically returned to baseline values in 1h post-treatment. The voltage of the nail-to-skin circuit was monitored during iontophoresis and compared to those observed in a skin-to-skin circuit. Nail-to-skin circuit voltages were generally approximately 50 V when the current was started and dropped fast to 20-30 V, a value comparable to that observed in the skin-to-skin circuit. On the whole, the clear enhancement of ionic transport observed, the feedback from volunteers, the small effects in TOWL, and the magnitude of voltages indicate that nail DC current iontophoresis is feasible and probably a safe technique.

Expression of follicular sheath keratins in the normal nail with special reference to the morphological analysis of the distal nail unit

BACKGROUND

The origin and the histology of the distal nail unit remain controversial. For some authors the nail bed is completely derived from the matrix epithelium and is not a self-regenerating, independent structure. The term onycholemmal keratinization has been used variably to describe both the so-called superficial horny layer without the granular layer of the nail bed, and the epidermal keratin of the hyponychium (HYN) and the eponychium. On the other hand, several contradictory systems of comparisons and homologies between components of the nail unit and those of the follicular sheaths have been proposed. Recently, the expression profiles of the epithelial keratins of the follicular sheaths have been determined in the human anagen hair follicle, but they have been only partially analyzed in the nail unit.

OBJECTIVE

This study was conducted to elucidate the morphology of the distal nail unit. To clarify the degree of homology between the nail unit and follicular sheaths, a selected set of keratins (K) was used.

METHODS

Formalin-fixed paraffin sections of adult nails were examined using mono- and polyclonal keratin antibodies, which are characteristic, respectively, for the inner root sheath, the companion layer, and the outer root sheath, as well as K10 and the antibody Ki-67 (antigen expressed in cycling cells). Longitudinal as well as transverse sections were investigated.

RESULTS

The pattern of the keratins in the nail unit differs from that of the follicle in two points: the lack of an IRS-like compartment and of the companion layer. The expression of K6hf was observed almost exclusively in the nail bed. K6 and K16 were expressed in the eponychium, the apical matrix, and the nail bed, but not in the ventral matrix. Distribution of K6 and K16 was essentially suprabasal. On the basis of morphologic and biochemical considerations, the distal nail unit can be divided into three segments. The nail bed, which represents the main segment of distal nail unit, does not differentiate into a thin, orthokeratinizing surface. The nail isthmus is typified by a peculiar mode of keratinization (ie, a compartment of pale, nucleated corneocytes), which is closely adherent to the inferior border of the nail plate, including its distal free edge. The nail isthmus presents a profile of keratin expression in transition between the nail bed and HYN. The keratin pattern of the nail bed, including K6hf, is maintained. However, the nail isthmus differs from the nail bed in that K10 is only present in nail isthmus. The HYN differs from the nail isthmus in that K6hf is absent in HYN. In addition, the HYN shows, progressively or abruptly, a loss of expression of K6/16, and K5/17 expression returns to a basal pattern. The mean Ki-67 labeling index of ventral matrix, nail bed including nail isthmus, and distal HYN were, respectively, 21.16%, 5.2%, and 16.43%.

CONCLUSION

The nail bed epithelium is an independent, specialized, epithelial structure with a true basal layer presenting a heterogeneous but significant proliferative activity. The so-called horny layer of the nail bed corresponds, in fact, to the superficial cells of the spinous layer of the nail bed. In this zone, the intercellular "spines" are barely detectable between cells replete with pink to brightly eosinophilic cytoplasm. The interlocking of the inferior border of the nail plate and the surface of the bed explain the strong attachment between the two tissues. The nail isthmus represents a transitional zone between the nail bed and the HYN and exhibits a pattern of keratinization different from the HYN. The cornified layer of the nail isthmus closely adheres to the undulating inferior surface of the nail plate; the two grow forward together. Therefore, the horny layer of the nail isthmus offers an effective sealing of the distal nail bed, preventing onycholysis. The terms matricial keratinization and onycholemmal keratinization could describe, respectively, the keratinization of the matrix and the nail isthmus.

Nail matrix biopsy of longitudinal melanonychia: Diagnostic algorithm including the matrix shave biopsy

Longitudinal melanonychia (LM) may represent nail matrix melanocyte activation (defined as a normal number of melanocytes with increased production of melanin), benign hyperplasia, or melanoma, in addition to multiple nonmelanocyte pathologies, including hemorrhage and infection. This article details an algorithmic approach to LM, including a careful history and physical examination, dermoscopy, and ability to sample the matrix using 3 biopsy techniques, a 3-mm punch excision, a lateral longitudinal excision, and a matrix shave biopsy. Facility with all 3 techniques will allow the physician to procure appropriate nail matrix specimens for diagnosis.

Nail surgery: practical tips and treatment options

This paper provides an introductory overview of nail surgery, including basic principles, anesthesia, wound dressings, and several common nail procedures. In detail, it reviews how to achieve complete anesthesia and hemostasis, perform matrix injection, punch biopsy of the plate, bed, and matrix, and nail fold biopsy, with practical tips and suggested surgical indications.

Surgical Anatomy of the Nail Apparatus

Nail surgery is an integral part of dermatologic surgery. An in-depth knowledge of the anatomy, biology, physiology, and gross pathology of the entire nail unit is essential. In particular, knowledge of nail histopathology is necessary to perform diagnostic nail biopsies and other nail procedures correctly.

Expression of hair keratins in the adult nail unit: an immunohistochemical analysis of the onychogenesis in the proximal nail fold, matrix and nail bed

BACKGROUND

Recently, the expression profiles of the members of the complex hair keratin family have been determined in the human anagen hair follicle. In contrast, the details of hair keratin expression in the human nail unit are poorly known.

OBJECTIVES

In order to fill this gap, we have performed an immunohistochemical study of the adult human nail unit by means of specific antibodies against nine hair keratins of both types (hHa2, hHb2, hHa5, hHb5, hHa1, hHb1, hHb6, hHa4 and hHa8) as well as three epithelial keratins (K5, K17 and K10).

METHODS

Formalin-fixed paraffin sections of adult nails were examined using monoclonal and polyclonal keratin antibodies, respectively. Longitudinal as well as transverse sections were investigated.

RESULTS

Our study revealed two types of epithelial tissue compartments in the nail unit. The first comprised the eponychium and hyponychium and the nail bed, which expressed only epithelial keratins. While keratins K5, K17 (basal) and K10 (suprabasal) were found in the orthokeratinizing eponychium and hyponychium, throughout, the nail bed epithelium expressed only K5 and K17. The second type comprised the apical and ventral matrix which exhibited a mixed pattern of epithelial and hair keratin expression. Thus, K5 and K17 were expressed in the entire multilayered basal cell compartment of the apical and ventral matrix; however, in the latter, K5 and K17 also occurred in the lowermost layers of the overlying keratogenous zone. The hair matrix keratin hHb5, but not its type II partner hHa5, was seen in the entire keratogenous zone of the apical and ventral matrix, but was also located in the uppermost cell layers of the basal compartment of the ventral matrix, where it overlapped with K5 and K17. Similar to their sequential expression in the hair follicle cortex, hair keratins hHa1, hHb1, hHb6 and hHa4 were consecutively expressed in the keratogenous zone of both the ventral and, albeit less distinctly, apical matrix, with hHa1 initiating in the lowermost cell layers. The expression of hHa8 in only single cortex cells of the hair follicle was also preserved in cells of the keratogenous zone. In the region of the so-called dorsal matrix, we observed two histologically and histochemically distinct types of epithelia: (i) a dominant type, histologically similar to the eponychium and an associated K5, K17 and K10 keratin pattern which clearly extended into the apical matrix, and (ii) a minor type, histologically resembling the postulated dorsal matrix without a granular layer and a cuticle, and exhibiting extended K5 expression as well as hair keratin expression in superficial cells.

CONCLUSIONS

The coexpression of hHb5 with K5 and K17 in the uppermost cell layers of the basal compartment and the lowermost layers of the keratogenous zone of the ventral matrix prompts us to designate this region the prekeratogenous zone of the ventral matrix. The two alternating types of histology and keratin expression in the dorsal matrix identify this region as a transitional zone between the eponychium and the apical matrix. Finally, our data clearly show that the ventral matrix is the main source of the nail plate. In addition, the mixed scenario of hair and epithelial keratins, including demonstrable amounts of K10, in superficial cells of the apical matrix, lends support to the notion that the dorsal portion of the nail is generated by the apical matrix.

Hereditary 'white nails': a genetic and structural study

BACKGROUND

Hereditary subtotal leuconychia is a rare nail disease. The gene(s) underlying this phenotype is (are) not known. Immunohistochemical and ultrastructural studies of nails are performed infrequently.

OBJECTIVES

To perform genetic linkage analysis and to assess ultrastructure and soft/hard keratin expression in hereditary white nails.

METHODS

We have analysed microscopically and ultrastructurally the white nails of a patient from a family in which the trait is inherited in an autosomal dominant manner as an isolated symptom. No skin lesions or hair abnormalities could be detected. Genetic linkage studies were performed on DNA samples obtained from several members of the affected family. A longitudinal surgical biopsy of the nail from a great toe was split in two parts. One part was fixed in formalin and processed for histopathology. Another part was further subdivided and embedded either in Epon, following fixation in 2% glutaraldehyde, or in Lowicryl K4M, after fixation in 3% paraformaldehyde. Dewaxed nail sections and Lowicryl ultrathin sections were also stained with various antikeratin antibodies.

RESULTS

Genetic linkage studies of the family pointed to the disease gene mapping to the chromosomal 12q13 region. Genes mapping within this chromosomal region include the genes coding for type II (basic) cytokeratins and hard keratins. The nail matrix presented an abnormal hypergranulosis. The upper part of the nail plate, originating from the proximal nail matrix, had a nonhomogeneous lamellar appearance, with numerous intracellular 'lipidic' vacuoles and 'empty' spaces separating keratin filament bundles. These cells were progressively shed at the nail surface. The cell loss was compensated by hyperproliferation of the distal matrix and of the nail bed keratinocytes, with persistent marked parakeratosis and loose arrangement of keratin bundles. The distal matrix and the nail bed contributed equally to formation of the lower plate. This presented the characteristics of a tissue composed of soft keratins. Accordingly, there was virtually no labelling with the Hb1 antibody to a basic hard keratin in the white nail, whereas the labelling with AE3 antibody to all type II keratins and with KL1 recognizing suprabasal soft keratins was normal or even enhanced.

CONCLUSIONS

Genetic linkage indicates that the gene defect underlying the leuconychia in the family studied resides on chromosome 12q13. As the type II keratins map within this chromosomal interval, it is possible that a mutation in one of these keratin genes may be a cause of the hereditary leuconychia. The white appearance of nails in this disease seems to be due to an abnormal keratinization of cells originating from the proximal nail matrix, leading to the presence of abundant intracellular vacuoles and to a lesser compactness of keratins.

Modulation of linear nail growth to treat diseases of the nail

Diseases affecting the nail can cause significant distress and interfere with an individual's self-esteem, personal relationships, and professional life. Often, hand and foot function is adversely affected. Certain diseases are characterized by accelerated nail growth while others show a decrease. In this review, drugs known to influence the growth rate of nails are examined, highlighting their potential use as adjunctive therapy in the treatment of nail disease. This approach, described recently in the context of the yellow nail syndrome,(1) may be extended to other common disorders such as nail psoriasis, brittle nails, and onychomycosis.

Acquired periungual fibrokeratoma with accessory germinal matrix

Five cases of acquired periungual fibrokeratoma involving the proximal nail fold were treated surgically. Clinically, all five patients regained normal nail contours postoperatively, but one patient developed a local recurrence 1 year after operation. Histologically, an accessory germinal matrix was observed at the distal end of the lesion in all five cases. Change in pressure around the lesion seemed to have induced the formation of this accessory germinal matrix.

[Treatment of post-traumatic nail bed deformities with split-thickness nail bed grafts]

INTRODUCTION

Split-thickness nail bed graft have been proposed for treatment of post-traumatic nail bed dystrophies. Only three papers reported good results in 60 to 90% of cases. We report our experience.

MATERIAL AND METHODS

We reviewed 18 cases of split-thickness nail bed grafts from operative and consultation files and photographs. Evaluation was made using criteria as the nail plate shape, its adhesion on the nail bed, patient satisfaction and possible sequelae on the donor finger. RESULTANTS: Thirteen patients have been reviewed with a sufficient follow-up to assess the results. In 13 cases, the graft was taken from the hallux. The nail-bed graft was used for hallux reconstruction two times, the thumb six times, index six times, middle and ring finger one each, and the little finger two times. In every patient the graft was molded using either the patient nail or the nail plate from the donor finger. Clinical results were excellent in five cases, good in three and poor in five cases. Five failures were due to wrong indications in three cases in which matrix problem has been underestimated, and infectious failures in two cases. Fifteen per cent of our patients had some sequelae on the donor finger.

Reconstruction of an amputated fingertip by a prefabricated free volar forearm flap

An amputated fingertip was banked temporarily under the skin of the volar wrist. This prefabricated fingertip was transferred back to the finger 2 months later, together with a free flap from the volar wrist based on the superficial palmar branch of the radial artery. The fingertip pulp showed a little pale pigmentation, but maintained its length well. The dorsal tip of the finger looked normal. This two-stage procedure made it possible to salvage the amputated bone and nail.

The physical basis of cosmetic defects of the nail plate

Cosmetic defects of the nail cover a range of changes. Some are variants of normal which are considered unattractive, others are part of the normal ageing process and some changes are manifestations of local or systemic disease. Interpretation of these changes relies on recognition of the specific characteristics in question and an understanding of the anatomy and biology of nails. In many instances, therapies are limited and explanation of the changes represents one of the most useful contributions the professional can make to the affected individual. This article covers some of the most common cosmetic defects of nail involving colour, surface, brittleness and behaviour of surrounding tissues. Understanding of the physical basis of these defects is limited in many cases, but current thinking is recorded.

Examination of the anatomic relationship of the proximal germinal nail matrix to the extensor tendon insertion

The purpose of this study was to delineate the relationship of the terminal extensor tendon insertion to the proximal limit of the germinal nail matrix. Sixteen fresh-frozen human cadaver fingers without any evidence of trauma (average age, 55 years; 3 males and 1 female) were used for this study. Under x25 magnification the proximal limit of the germinal nail matrix and the terminal bony insertion of the extensor tendon were identified. The distance from the terminal tendon insertion to the germinal nail matrix was ascertained using precision calipers. The average distance from the terminal extensor tendon insertion to the proximal edge of the germinal nail matrix was found to be 1.2 mm. We conclude that the proximal limit of the germinal matrix is extremely close to the terminal extensor tendon bony insertion. When the extensor tendon insertion is visualized during operative exposures of the dorsum of the distal phalanx, care should be taken to avoid damaging the germinal matrix. Conversely, when the nail bed is being completely excised, visualization of the insertion of the extensor tendon will indicate that further proximal dissection is not required.

Keratin expression in the normal nail unit: markers of regional differentiation

Differentiation within the nail unit was examined using a range of antikeratin monoclonal antibodies including the recently described antibody LHTric-1, specific to the acidic hair-type keratin Ha1. Keratinocytes of the nail matrix, nail bed and the digit pulp were characterized by different patterns of keratin expression. Nail matrix was the sole site of expression of Ha1, which colocalized in suprabasal matrix epidermis with epidermal keratins K1 and K10. Small amounts of K17 were found at the apex of the matrix in some cases. K6 and K16 were found where the epidermal surface folds forwards to become the ventral aspect of the proximal nail fold. The nail bed was distinguished by the absence of hair-type keratin Ha1 and the absence of markers of cornified epidermis and mucosal differentiation K1/K10 and K4/K13, respectively, while K6, K16 and K17 were detected. The basal keratin conformation marker, LH6, was expressed suprabasally throughout the nail bed. This complement of keratins exists in the nail bed in the absence of notable proliferative activity, and suggests a state of minimally developed differentiation which may be afforded by the physical or biological properties of the overlying nail. Keratins, K6, K16 and K17 were all found in the digit pulp in limited amounts, possibly in association with the epidermal component of the eccrine duct. The simple epithelial keratins, K7, K8 and K18, were found in small amounts in the specimens from younger individuals, mainly in epibasal cells of the apex of the matrix and in putative Merkel cells.

Yellow nail syndrome: the nail that grows half as fast grows twice as thick

We report a case of a 51-year-old man with yellow nail syndrome (YNS).1 During a 23-week period of study, the dynamics of thumbnail growth were compared between one affected thumb and the normal contralateral thumb. Longitudinal nail growth was normal (0.46 mm/week) in the normal thumb and double that of the affected thumb (0.23 mm/week). Thickness of nail at the free edge in the affected thumb (0.97 mm) was twice that of the normal thumb (0.57 mm). Within the nail plate in the dorso-ventral axis there were 50% more cells in the affected thumb (358) in comparison with the contralateral control (242). This case illustrates that rate of longitudinal growth does not necessarily reflect nail plate production.