CARACTERÍSTICAS
INSPECCIÓN ANTES DE CONDUCIR
Bertrand Richert
The close neighboring of the distal interphalangeal joint with the most proximal part of the matrix is of major importance in surgical anatomy, especially when performing a complete resection of the nail apparatus for a malignant process with wide mar- gins. In pathology, the complex formed by the distal interphalangeal joint and the matrix is considered nowadays as an enthesis, explaining the propagation of some inflammatory diseases (psoriasis) from the joint to the matrix.
MYXOID CYST (GANGLION CYST) Introduction
It is now quite well admitted that digital myxoid cysts (DMC) result from a joint fluid leaking (1) from a degenerative distal interphalangeal joint (DIJ) (2). MRI has shown that more than 80% of myxoid pseudocysts exhibit a communication between the cyst and the joint (Fig. 1) (3). On histology they do not show any lining, so the term cyst, although commonly accepted, is a misnomer and the term myxoid pseudocyst should be preferred (4). They present as a translucent nodule, typically arising on the dorsum of the digit, somewhere between the DIJ crease and the proximal nail fold (PNF) (Fig. 2). The most distal DMC may press on the underlying matrix and produce a longitudinal groove on the nail plate, the depth of which varies according to the pressure exerted by the volume of the lesion on the matrix (Figs. 3A, B and 7A). In all these locations, they may occasionally discharge some mucinous content with subsequent decompression of the nodule, which is later seen as an irregularity in the longitudinal depression of the nail. In some rare instances, a DMC develops under the matrix (see “Submatricial Myxoid Pseudocyst,” pp. 122–124). When the DMC is small and located very distally on the PNF it may be removed in the same manner as chronic parony- chia (see “Crescent Excision,” pp. 46–47).
A wide range of therapies have been proposed to remove DMCs: repeated puncture associated with compressive dressings, cryotherapy (5), injection of sclerosant (6), CO2laser (7), infrared coagulation (8), but none has been able to reach the high rate of success (over 90%) achieved with surgery (1,4). Several techniques are available, all of them directed toward inducing some fibrosis around the joint to
stop leaking of the joint fluid. Hand surgeons usually remove the osteophytes and “clean” the joint cap- sule. This leads to very good results, but this aggressive surgery requires long-time immobiliza- tion of the DIJ and may result in restriction of joint mobility (up to 25%) and the post op is long and painful for the patients (9). Others propose flaps (10,11) or grafts (12) and it has been shown that skin removal is often not required (13).
Methylene blue–guided surgery for ligature of the leak of joint fluid is a very elegant, quick and effective technique (4) as it provides very high success rate on the fingers (94%). On the toes, the technique reaches only 57% probably because in this location the presssure of fluid escaping from the joint is increased by the weight of the standing position (1). This procedure is also very comfortable for the patient.
Anesthesia
l Distal digital block, starting on the lateral sides
of the DIJ, to ensure complete anesthesia of the joint. Transthecal anesthesia on the fingers and proximal digital block are other options.
Tools
l Tourniquet
l Standard nail surgery tray l Sterile methylene blue solution l Insulin syringe, 30G needle l Absorbable suture 5/0
Surgical Procedure
Technique: intermediate to difficult
l Insert the needle of an insulin syringe into the
flexural crease of the DIJ, about 5 mm proximally to its midline, with the joint slightly flexed, needle pointed distally with an angle of 308 to 458 to the ventral aspect of the second phalanx (Fig. 4). Push the needle until it hits the bone. Withdraw the needle backward, very gently while pressing on the plunger. Resistance to injection means that the needle is within the periosteum; ease of the injection means that the needle is within the joint.
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l Never inject more than 0.1 mL (10 units on the
insulin syringe), or the whole operating field will turn blue. The average amount is usually around 0.05 mL (five insulin units).
l Remove the needle and exercise the joint several
times to have the blue dye circulating. Observe closely the DMC as a pale bluish hue will appear confirming the communication (Fig. 5).
l Apply the tourniquet.
l Design a flap around the DMC: a good option,
when feasible, is to use the dorsal creases as a horizontal incision posterior to the DMC, then a lateral incision running on the lateral aspect of the finger will free a large flap that allows visualization of the surroundings of the base of the pseudocyst (Figs. 6A and 7B).
l The leak may present in various sizes from a thin
blue line to a large one.
Figure 1 MRI showing connection between the cyst and the joint.
Figure 2 Typical presentation of digital myxoid cyst between the proximal nail fold and the distal interphalangeal joint.
Figure 3 (A) DMC pressing on the underlying matrix. This DMC never varies in size, thus inducing a smooth and regular groove. (B) DMC that varies in size over time; the groove facing it is irregular. Abbreviation: DMC, digital myxoid cyst.
Figure 4 Introduction of the needle into the ventral aspect of the digit to reach the capsule. Compare with Figure 9.
Figure 6 (A) Elevation of a lateral flap showing a large pedicle. (B) Ligation of the pedicle.
Figure 7 (A) Irregular nail plate from a digital myxoid cyst pressing onto the matrix. (B) Elevation of a flap showing the pedicle. (C) Closure by simple nonabsorbable sutures. (D) Aspect of the plate after seven months. Compare with (A).
Figure 5 The cyst shows a pale hue, confirming connec- tion between the joint and the cyst.
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l Tie off the connecting stalk with absorbable 5/0
suture (Fig. 6B). One stitch per blue line is usually enough. Placing to many stitches may induce some extra inflammatory reaction post operatively.
l Lay back the flap and suture it back in place.
Nonabsorbable suture is classically used, but the absorbable suture previously used may fit nicely, they are more comfortable post operatively. Separate stitches (Fig. 7C) or a running suture are two possible options (Fig. 8D).
l In our series, we where wondering why some
cysts turning blue after injection and in which the stalks were tied off recurred. When designing a flap that exposes the whole dorsal aspect of DIJ, we noted in some instances (about 10% of cases) that some communications between the cyst and the joint were very laterally located (Fig. 8A) and would not have been ligated (Fig. 8B, C) by a flap designed only around the cyst. Since we are using this procedure, we dramatically increased our success rate to almost 100%. It may be so that the large fibrosis induced around the by healing of this large flap plays a part in this success.
Key Point
l Injection of methylene blue within the joint
capsule and visualization of the leak after reflection of a dorsal flap. Check the sagittal view on a cadaver finger (Fig. 9).
l Do not inject too much of methylene blue. l Do not place too many stitches around the
pedicles.
Figure 8 (A) Complete reflection of dorsal aspect of the distal phalanx shows two large stalks: one is facing the lesion, and the other one is very laterally located. (B) Suturing the pedicles with 5/0 absorbable sutures. (C) Suturing completed. (D) Running suture with 4/0 nonabsorbable sutures.
Figure 9 Injection within the capsule on section on cadaver. Source: Courtesy of D.A.R. de Berker, Bristol, U.K.
Postoperative Care Pain: very little
l Dress the wound with antiseptic ointment, a
tulle gras, and a bulky dressing.
l Ask the patient to elevate the limb for 48 hours:
ask her/him to come with a large scarf that will be used as a sling.
l Skin sutures are removed after 10 to 15 days.
Evolution
l Healing is very rapid.
l Main trouble is rigidity that appears in a few
days as the dressing maintains the finger straight. The dressing should be removed after two days, and a small dressing covering only the dorsal aspect of the distal phalanx should be placed. Physiotherapy should be taught to the patient: bending the distal phalanx while block- ing the proximal interphalangeal joint with the opposite hand. Full mobility is recovered in less than three weeks.
l Check the patient after three months. The nail
should grow out without the longitudinal groove, thus proving the success of the proce- dure. After six months the nail shows no more surface alteration (Fig. 7D).
Complications and Management
l They are very unusual.
l As for subungual exostosis, this surgery must be
performed in an operating room that meets orthopedic surgery standards. Strict adherence to aseptic operative techniques is required.
l No prophylactic antibiotics are needed as long as
there is no rupture of the capsule.
l Irritation from the suture on the pedicle may
occur in some instances, and present by a redness associated with a discrete swelling of the overlying skin (Fig. 10). Gentle massage for several weeks with some steroid cream enhances resolution. Healing occurs with complete resorp- tion of the stitches that may take up to three months, according to the type of suture used. This mostly occurs when placing a large number of deep stitches. In two cases, there was perfo- ration of the skin with extrusion of one extremity of a stitch. Cutting it very short allowed rapid complete healing in one, in the other a tiny retractile scar developed (Fig. 11).
REFERENCES
1. de Berker D, Lawrence C. Ganglion of the distal interphalangeal joint (myxoid cyst): therapy by identi- fication and repair of the leak of joint fluid. Arch Dermatol 2001; 137:607–610.
2. Lin YC, Wu YH, Scher RK. Nail changes and associ- ation of osteoarthritis in digital myxoid cyst. Dermatol Surg 2008; 34:364–369.
3. Drape´ JL, Idy Peretti I, Goettmann S, et al. MR imaging of digital myxoid cysts. Dermatol Surg 1996; 200: 531–536.
4. Haneke E. Operative Therapie der myxoiden Pseudo- zyste. In: Haneke E, ed. Gegenwa¨rtiger Stand der Operativen Dermatologie. Fortschritte der Operativen Dermatologie 4. Heidelberg: Springer, 1988:221–227.
Figure 11 Retractile scar from a subcutaneous stitch. This was later excised and sutured, with very good outcome. Figure 10 Irritation of the dorsal aspect of the distal phalanx from overzealous suturing of the pedicles.
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5. de Berker DA, Lawrence CM. Treatment of myxoid cysts. Dermatol Surg 2001; 27:296–299.
6. Audebert C. Treatment of myxoid cysts of fingers and toes by injection of sclerosants. Dermatol Clin 1989; 7: 179–182.
7. Hueter CJ, Whelland RG, Bailin PL, et al. Treatment of digital myxoid cysts with carbon dioxide laser vapor- ization. J Dermatol Surg Oncol 1987; 13:723–727. 8. Lonsdale-Eccles AA, Langtry JA. Treatment of digital
myxoid cysts with infrared coagulation: a retrospective case series. Br J Dermatol 2005; 153:972–975.
9. Kasdan ML, Stallings SP, Leis VM, et al. Outcome of mucous cyst of the hand. J Hand Surg 1994; 19A: 504–507.
10. Blanc S, Candelier G, Bonnan J, et al. Use of a bilobed flap for the treatment of mucous cyst. Chir Main 2004; 23:137–141.
11. Imran D, Koukkou C, Bainbridge C. The rhomboid flap: a simple technique to cover the skin defect prodiced by excision of a mucous cyst of a digit. J Bone Joint Surg 2003; 85B:860–862.
12. Jamnadas-Khoda B, Agarwal R, Harper R, et al. Use of Wolfe graft for the treatment of mucous cysts. J Hand Surg Eur Vol 2009; [Epub ahead of print].
13. Lawrence C. Skin excision and osteophytes removal is not required in the surgical treatment of digital myxoid cysts. Arch Dermatol 2005; 141:1560–1564.