CARACTERÍSTICAS
PUESTA EN MARCHA DEL MOTOR
Bertrand Richert, Eckart Haneke, and Nilton Di Chiacchio
The nail bed represents more than the two-third of the whole length of the nail apparatus. It is reachable only after nail avulsion unless some process may be responsible for its disappearance. As it regenerates very easily and because nail dystrophies are very unlikely, the nail surgeon should not be afraid of working on it.
NAIL BED BIOPSY Introduction
l Indications for nail bed biopsies are the diseases
of the bed presenting as an onycholysis, a subungual hyperkeratosis or a tumor of the nail bed (1).
l As the epithelium of the nail bed is tightly
adherent to the ventral aspect of the plate, it may be damaged by nail avulsion and/or its upper part will remain attached to the plate after avulsion. In inflammatory diseases (i.e., psoriasis and lichen planus), nail plate and bed epithelium should undergo histopathologic examination; therefore avulsion should be avoided (2,3).
l Nail plate avulsion (total or partial) is indicated in
cases where histologic examination of the epithe- lium is not important (mostly tumors) (2,3).
l Larger nail bed defects may result in permanent
onycholysis. It has been advocated that the width of the defect should not exceed 4 mm (4).
Anesthesia
l Proximal or distal digital block
Tools
l Tourniquet
l Blade No. 11, 15, 15C
l Biopsy punch 3, 4, and 6 mm l Nail elevator
l Sharp fine-tipped curved scissor (Graddle or
LaGrange)
l Absorbable suture 4-0 or 5-0
l Sterile absorbable gelatin sponge (Gelfoam1)
Surgical Procedure
Technique: easy, except for the double-punch technique, intermediate
— With nail plate avulsion A tourniquet is placed.
The nail plate is avulsed (see “Nail Plate Avulsion,” pp. 31–41). Total nail avulsion is only required if necessary for exposure or surgical exploration. Partial nail plate avul- sion is more elegant, less invasive, and enough to allow adequate sampling for histological diagnosis (5).
After avulsion, punch biopsy of the bed (Figs. 1–3) is as simple as at any other site: the punch is pushed, perpendicular to the surface of the bed, in a rotating motion until hitting the bone. Sharp pointed tipped scissors (Graddle and LaGrange) are gently inserted at the level of the periosteum to release the specimen (5). Forceps should never be used as the fragile specimen may be crushed between the jaws (6). The specimen, once snipped, should only be harvested with a gauze or with the scissors tips. Bleeding is minimal and may be stopped with hemostatic solution. If not, a piece of Gelfoam may be pushed into the defect. A more elegant way of punching the bed is
the double-punch technique (7) (Figs. 4–6). A 6-mm punch is made through the plate only. The disk of keratin is removed with the tip of a No. 11 blade or an injection needle the tip of which had been bent at 908 before, and a smaller punch of 3 mm is performed on the nail bed down to the underlying bone. The enlarged hole in the plate overcomes the difficulty to harvest the biopsy material from a narrow window in the nail plate. Harvesting the specimen with sharp pointed curved tipped scissors from the bone is much facilitated. The keratin disk may be replaced and secured with adhesive strips and will act as a dressing. If the plate is needed for histology, the hole is filled with Gelfoam.
[vijay][246X189_UK_Tight][D:/informa_Publishing/Richert_2400061/z_production/z_3B2_3D_files/ 978-0-4154-7233-3_CH0007_O.3d] [23/11/010/16:6:8] [55–84]
If a larger specimen is required, then a longitudinal elliptical biopsy (Figs. 7–10) should be performed: the incision lines should be long and narrow and the specimen detached from the bone with sharp pointed scissors or with a blade (Beaver blades are particularly adequate). The ellipse can be as narrow as 2 mm as it will be cut longitudinally and extra width will not add to the suitability of the specimen, but make wound closure more difficult. Again, the specimen should never be handled with forceps at any time. As the bed has no laxity at all, it is mandatory to undermine the edges of the ellipse: the blade, resting flat on the bone, is gently slid laterally under the edges of the wound on at least 5 mm. This usually allows primary closure of the defect with 4-0 or 5-0 absorb-
able sutures. Do not pull on the lateral edges either with the forceps or the stitches, as it may tear off the bed. Reapproximation is enough, and the small remaining defect will close by secondary intention.
—Without nail plate avulsion A tourniquet is placed.
The specimen of nail bed should be harvested through the nail plate and that may be more difficult. To facilitate the cutting through the nail, the digit may be soaked in warm water for 10 minutes to soften the plate. Another option is to thin the nail by electric grinding (6). A 4-mm punch is pushed through the plate down to the bone. When withdrawing the punch, most of the time the disk of keratin will remain stuck in the metallic cylinder of the
Figure 1 Toenail before biopsy. Figure 2 After partial nail plate avul- sion, a 3-mm punch is performed in the nail bed and harvested.
Figure 3 Gelfoam placed in the defect allows perfect hemostasis.
Figure 4 A 6-mm punch avulses a keratin disk.
Figure 5 A 3-mm punch is pushed down to the bone and harvested with fine curved scissors.
Figure 6 The keratin disk is put back in place.
punch. Harvesting of the specimen is difficult and should be very delicate using very fine sharp pointed and curved scissors or, again, a 27G needle with its tip bent 908; this also allows the nail plate disc to be gotten out. Never use any forceps. Extirpation of the specimen should be done with the scissors tips. Never use forceps. Gelfoam is pushed into the hole. This type of biopsy is not recommended by the
authors, unless it involves the free edge of the plate (Figs. 11–13).
Key Point
l The choice of biopsy technique (with or without
avulsion) will depend on the suspected diagnosis.
l If the bed epithelium is important for histopa-
thologic examination, the nail plate should be kept along with the bed specimen.
Figure 9 An elliptic excision is carried out in the longitudinal axis of the bed.
Figure 7 Toenail before biopsy. Figure 8 Partial avulsion of the plate.
[gajendra][246X189_UK_Tight][D:/informa_Publishing/Richert_2400061/z_production/z_3B2_3D_files/ 978-0-4154-7233-3_CH0007_O.3d] [19/11/010/1:59:52] [55–84]
l Specimens with nail plate attached are very
difficult to harvest, therefore thinning the plate is of great help. They are also very difficult to handle in the histopathology lab.
l As a help for an easy reapproximation of an
elliptical biopsy of the bed, lateral undermining of the edges should be generous.
Postoperative Care
Postoperative pain: very little for punch biopsy, little for elliptical biopsy
l Greasy nonadherent dressing. l Weak pain killers are enough.
l Removal of the dressing at 24 hours, soakings in
antiseptics twice daily for one week. Light dry dressing.
Evolution
l Healing is fast without scarring or dystrophy.
Complications and Management
l Bleeding is the most common complication.
Compression, elevation of the limb and Gelfoam are of great help.
l If a total avulsion was performed for surgical
exploration purposes, it should be put back in place as it will act as a physiological dressing.
l It is said that defects larger that 4 mm on the bed
will lead to permanent onycholysis. Neverthe- less, it is amazing to note that very large defect of
the nail bed after Mohs surgery may regenerate totally by secondary intention (1) (Figs. 14 and 15). One should then feel very comfortable with nail bed biopsies.
Figure 11 Distal hyperkeratosis of the nail bed.
Figure 12 A 3.5 mm punch is pushed perpendicular to the plate down to the bone.
Figure 13 Harvesting the specimen is very easy as the scissors may be slid under the specimen from the hypo- nychium.
Figure 14 Defect after four sessions of Mohs surgery for Bowen’s disease of the nail bed.
Figure 15 Results after secondary intention healing.
TUMORS OF THE NAIL BED LONGITUDINAL ERYTHRONYCHIA Introduction
l Longitudinal erythronychia (LE) defines a longi-
tudinal red streak, usually from 2 to 3 mm wide, running from the distal matrix up to the point of separation of the nail plate and nail bed. It may be associated with some splinter hemorrhages. At the distal edge, focal onycholysis, nail split- ting, and subungual hyperkeratosis may be observed (8) (Fig. 16).
l Multiple LE can represent multifocal inflamma-
tory diseases such as lichen planus or dysker- atosis follicularis of Darier White (8) when associated with longitudinal leuconychia.
l It is recommended to remove surgically the
isolated LE as histopathologic examination may reveal an inflammatory disease such as lichen planus (9), a benign tumor such as warty dysker- atoma (10), hyperplastic glomus structures (8), acantholytic dyskeratotic acanthoma (11), onycho- papilloma with (12) or without multinucleated cells (13), but also a malignant tumor such as Bowen’s disease (13,14) or basal cell carcinoma (15).
l The term onychopapilloma is a useful descriptive
term but may not represent comparable histology in all instances and should be discarded (15). Anesthesia
l Distal digital block, unilateral or bilateral accord-
ing to the location of the lesion. Another option is a transthecal block.
Tools
l Nail avulsion tray l Basic nail surgery tray
Surgical Procedure Technique: intermediate
l To expose the lesion on its whole length two
options are possible: partial longitudinal avul- sion with plate replacement or total distal avulsion with plate replacement (lateral curled nail avulsion is best, trap door avulsion is an alternative). Partial longitudinal avulsion will allow excising the lesion on its whole length but it has to be wide enough to allow suturing between the lateral edges of the attached nail plate (Fig. 17).
l If the lesion is large and the defect suspected to
be wide, then complete distal nail avulsion is recommended (Fig. 18A, B).
l Incise the nail bed around the lesion in a
longitudinal ellipse, with no safety margins. The most proximal part of the ellipse should include the distal matrix (Fig. 18C).
l Carefully dissect the specimen from the bone
with sharp and fine pointed scissors (i.e., Graddle), starting from the hyponychium and progressing proximally (Fig. 18D). An alterna- tive is to push a Beaver blade No. 64 just above the periosteum in a distal to proximal motion to
[vijay][246X189_UK_Tight][D:/informa_Publishing/Richert_2400061/z_production/z_3B2_3D_files/ 978-0-4154-7233-3_CH0007_O.3d] [19/11/010/1:59:52] [55–84]
Figure 18 (A) Large distal onycholysis with suspicion of a large potential defect. (B) Lateral curled nail avulsion exposing the tumor. (C) Elliptic longitudinal incision around the tumor including the most distal part of the matrix. (D) The defect after removal of the tumor is wider than 5 mm and needs closure by flaps. (E) Undermining the sides of the wound. (F) Relaxing incision on one side of the wound freeing a first flap. (G) Relaxing incision on the other side freeing the second flap. (H) Reapproximation of the two flaps with 5-0 absorbable sutures. (I) The plate is put back in place and secured to the lateral nail fold.
detach the specimen. This procedure is less traumatic than dissection with scissors.
l If the defect is less than 4 mm wide, secondary
intention healing is an option, but there is a slight risk of onycholysis. Therefore, it is better to try to close the defect: always undermine each side of the wound using the scalpel blade, firmly pressed onto the bone (Fig. 18E) and reapprox- imate roughly the margins with absorbable sutures. Start suturing the proximal bed first to avoid pulling excessively on the matrix (Fig. 19A). Then suture the hyponychium and complete with the middle part of the bed. Reapproximation is perfect in the most distal and proximal portion with a very light gap in its middle part (Fig. 19B).
l If the defect is larger than 4 mm, then the defect
should be closed by two lateral flaps: perform two longitudinal incisions parallel to the defect
about 4 to 5 mm lateral to each margin or along the lateral sulci. Free these two flaps by under- mining (slide the scalpel blade under the bed and perform gentle back-and-forth motions until complete freeing) (Fig. 18F, G).
l Reapproximate the defect with 5-0 or 6-0
absorbable sutures. Do not pull too much on the suture to avoid tearing the bed (Fig. 18H).
l Flip back the plate and secure it to the lateral
folds and distal wall (Fig. 18I). Key Point
l Suturing between the lateral edges of the plate
still attached to its bed is difficult (Fig. 17).
l Undermining the bed widely to ensure sliding of
the flaps (Fig. 18E).
l Suturing the bed before the matrix.
l A parallel pulley suture helps greatly and takes
tension from the single stitch sutures.
[gajendra][246X189_UK_Tight][D:/informa_Publishing/Richert_2400061/z_production/z_3B2_3D_files/ 978-0-4154-7233-3_CH0007_O.3d] [19/11/010/1:59:52] [55–84]
Postoperative Care
Postoperative pain: light to moderate
l Greasy antiseptic slightly compressive dressing l Elevation of the limb for two days
Evolution
l Remove the stitches securing the plate to the
folds after three weeks.
l Ask the patient to secure the plate with adhesive
tape and to keep it in place as long as possible.
l When the nail is shed, complete healing of the
bed has already occurred and a new nail has grown to about one-third of its length.
l The scar in the bed may appear as a longitudinal
leuconychia or erythronychia.
l Even very large defects may heal very nicely
with this technique (Fig. 20A–D). Complications and Management
l Secondary healing may result in some onychol-
ysis if the defect was over 4 mm.
l A thinner nail may be observed from the partial
resection of the distal matrix. Easy breakage may occur at this point.
l A split results either from poor matrix suturing
or from removal of the proximal matrix. PYOGENIC GRANULOMA
Introduction
l Pyogenic granulomas are eruptive angiomas
most commonly developing after a minor trauma. When appearing in the nail bed, the trauma had to have pierced the nail plate, or may result from excessive rubbing of the shoe against the nail (16).
l Pyogenic granulomas are usually small, pea-
sized tumors that are rapidly eroded and tend to bleed easily.
l Whether the erosive and bleeding lesions
observed during/after treatment with retinoids, reverse transcriptase inhibitors, epidermal growth factor receptor inhibitors, docetaxel, mitoxantrone, and other drugs are true pyogenic granulomas as indicated in the literature or granuloma-like lesions more resembling granu- lation tissue remains to be clarified (17–19).
l Coccal nail fold angiomatosis is pyogenic gran-
uloma like but has some discriminatory factors (20).
Anesthesia
l Either proximal finger block, transthecal anes-
thesia, or bilateral wing block.
Tools
l Nail avulsion tray l Basic nail surgery tray l Curette
l Optional: hemostyptic agent or electro-/radio-
frequency cautery
Surgical Procedure Technique: easy
There are several possibilities to remove a nail bed pyogenic granuloma (21–23).
l When the lesion is subungual and presents with
onycholysis from the oozing (Fig. 21A), avulsion
Figure 19 (A) Suturing the proximal nail bed first avoids pulling excessively on the matrix. (B) Reapproximation is perfect in the most proximal and distal bed. Discrete gapping in its middle portion.
(either partial or lateral avulsion with replace- ment) will permit complete visualization of the lesion (Fig. 21B). The pyogenic granuloma may be cut horizontally at its base (Fig. 21C), or curetted and then gently cauterized using electrocautery or radiofrequency. When bleeding is mild and not pulsating a cotton-tipped applicator dipped into a hemostyptic solution such as 30% aluminum chloride or 20% to 40% ferric chloride is pressed on the small wound for a few minutes.
l The tumor may be cut off tangentially using an
electric loop.
l When the pyogenic granuloma is bigger and
located in the distal nail bed the plate overlying the lesion is generously cut away and the tumor
either removed tangentially as described above or excised and the defect sutured primarily. Alternative Treatments
l Cryotherapy may also be used (24).
l Carbon dioxide laser may be used to vaporize a
pyogenic granuloma, whereas selective vessel damage and occlusion is thought to be the mechanism of action of a dye laser (25).
l Recently, a subungual lesion was treated with
sodium tetradecyl sulfate sclerotherapy (26). Key Point
l Amelanotic melanoma is the most important
differential diagnosis of pyogenic granuloma.
Figure 20 (A) Very large onychopapilloma. (B) Very large defect on the bed after removal of the lesion. (C) Closure by two lateral flaps. (D) Outcome six months postoperatively. Note the absence of onycholysis and a residual light erythronychia from the scar in the bed.
[gajendra][246X189_UK_Tight][D:/informa_Publishing/Richert_2400061/z_production/z_3B2_3D_files/ 978-0-4154-7233-3_CH0007_O.3d] [19/11/010/1:59:52] [55–84]
Therefore, destructive therapies are not recom- mended as they do not allow histological exam- ination of the specimen.
Postoperative Care Pain: very little
l An antibiotic ointment, or tulle gras, is applied
with a bulky dressing for 24 hours. The ointment usually avoids sticking of the dressing to the wound. This may then be replaced by a small band aid with a bit of ointment. If the dressing is heavily blood-stained the dressing is gently dissolved with a lukewarm soaking.
Evolution
l Healing is fast. A crust will appear and fall off in
about two weeks.
l If the nail plate was avulsed, the new nail will
regrow without any dystrophy.
Complications and Management
l Simple horizontal excision, curettage, and cry-
otherapy are virtually free from complications except for possible recurrence.
l Electrocautery may damage the surrounding nail
bed tissue and matrix and has therefore to avoid too much heat generation. Excessive vaporization has to be avoided when using a CO2 laser. These may result in permanent onycholysis.
l Infection may follow surgery with sutures.
KERATOACANTHOMA Introduction
l Subungual keratoacanthoma (SUKA) should
now be considered as a borderline tumor as some American pathologists name it “squamous cell carcinoma keratoacanthoma type” or even “keratocarcinoma.”
l SUKA has a predilection for the three first
fingers, especially the thumb (27).
l Typically, KA is painful and arises very quickly
(within weeks).
l Clinical features associate onycholysis and ker-
atotic-crusted nodule of the distal nail bed (27) (Fig. 22A). Location within the proximal nail fold is unusual and results in a painful paronychia with creamy discharge (28).
l X-ray examination reveals a cup-shaped erosion
of the underlying bone without accompanying sclerosis or periosteal reaction. The lytic defect is the result of pressure erosion rather than tumor invasion (29).
l Multiple subungual KA-like lesions may arise as
a late manifestation of incontinentia pigmenti.
l Spontaneous involution as on the skin is excep-
tional.
Anesthesia
l Distal digital block.
Tools
l Basic nail surgery tray l Curette
Figure 21 (A) Proximal onycholysis and oozing. The dark discoloration results from application of silver nitrate. (B) Lateral nail plate avulsion exposes the tumor. (C) After shaving of the tumor at its base and application of hemostatic solution.
Surgical Procedure Technique: intermediate
l Partial avulsion (Fig. 22B), “trap door” or lateral
curled nail avulsion will expose the lesion.
l Most authors favor curettage. Histological con-
trol of the margins is then impossible and this technique should therefore not be recom- mended. One or two stitches on the sides of
the cavity may reapproximate the borders. Healing occurs then by secondary intention.
l Best treatment is Mohs’ surgery when available.
The lesion is excised “en bloc” sticking as close as possible to the bone (Fig. 22C). The specimen is orientated and fixed. New sessions are performed, if necessary, until the margins are cleared of tumor.
Figure 22 (A) Very painful distal onycholysis with extrusion of a chalky material. (B) Partial avulsion exposing the tumor. (C) En bloc excision of the tumor. (D) Reapproximation of the edges of the wound.
[gajendra][246X189_UK_Tight][D:/informa_Publishing/Richert_2400061/z_production/z_3B2_3D_files/ 978-0-4154-7233-3_CH0007_O.3d] [19/11/010/1:59:52] [55–84]
l Two stitches will grossly reapproximate the
margins of the defect and healing will occur partly by secondary intention (Fig. 22D).
l In both treatments, trap door and curled lateral
nail avulsion are better options as putting back the plate on the bed and securing it to the lateral folds will act as a physiological dressing and will enhance healing.
l For multiple lesions as observed in incontinentia
pigmenti, etretinate 1 mg/kg/day is an alternative.
Key Point
l Excision “en bloc” being as close as possible to
the bone.
l Margins free of residual tumor