To Tie or Not to Tie: The Dilemma of the Supernumerary Digit
Published on Physicians Practice (http://www.physicianspractice.com)
To Tie or Not to Tie: The Dilemma of the Supernumerary Digit
October 08, 2010
By Khalid H. Safi, MD [1] and Howard Fischer, MD [2]
An 11-day-old African American boy was brought in for a well-baby visit. Pregnancy, labor, and
delivery had been uncomplicated.
An 11-day-old African American boy was brought in for a well-baby visit. Pregnancy, labor, and
delivery had been uncomplicated. He had bilateral ulnar supernumerary digits, which had been
suture-ligated on day 2 of life. The digits had autoamputated, but necrotic stumps remained. His
mother stated that he was irritable and cried whenever these remnants were touched. The necrotic
stumps were removed in the office, under local anesthesia, with a scalpel.
Polydactyly—the presence of an extra finger or toe—is a common minor malformation. The
frequency of polydactyly in African Americans is 13.9 per 1000 births; this is 9 times the frequency
seen in US whites.1 Postaxial polydactyly (also called ulnar polydactyly) is the most common type
and refers to duplication of the little finger. In type A postaxial polydactyly, the extra digit is fully
developed. In type B postaxial polydactyly, the extra digit is rudimentary and pedunculated
(Figure).2
The usual method of treating type B postaxial polydactyly in the newborn is suture ligation at the
base of the pedicle, which produces necrosis and autoamputation. The most recent editions of 2
standard pediatric textbooks advise this approach.3,4
However, several treatment options are available for a neonate in whom type B postaxial polydactyly
is discovered. These include:
•cNo treatment (which is not really an option).
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To Tie or Not to Tie: The Dilemma of the Supernumerary Digit
Published on Physicians Practice (http://www.physicianspractice.com)
• Suture ligation.
• The use of local anesthesia and simple excision with scalpel or scissors.
• Surgical division of the pedicle with attentive transection of the accessory digital nerve branches,
followed by skin closure.
The Downside of Suture Ligation
Although suture ligation is simple to perform, it does have the potential for complications. Frieden
and colleagues5 describe an infected ligated supernumerary digit, and one report mentions a
necrosed digit that remained attached a month after ligation.2 A residual bump at the site of ligation
was found in 43% of patients examined at an average of 20 months of age.2
Another possible complication of suture ligation is the development of an amputation neuroma at the
ligation site.6-8 Leber and Gosain6 describe the operative and histological findings of neuroma in 3
children who had had 5 supernumerary digits ligated. Two of the patients presented with pain at the
neuroma site. When the authors examined the parents and grandparents of children referred for
treatment of supernumerary digits, they found at least 8 adults with sequelae of digit ligation. These
adults, and an additional adult in another report,8 had at least 1 of the following in the vestigial
remnant:
"discomfort on pressing or hitting the remnant, . . . tingling, . . . and intermittent bleeding or
ulceration." Leber and Gosain6 thus conclude that the true incidence of neuroma formation following
suture ligation of pedunculated supernumerary digits in infancy may be much higher than previously
thought." Amputation neuromas arise, according to Leber and Gosain,6 because ligation does not
properly treat the digital nerve that is always present in the supernumerary digit. The authors
explain why ligation predisposes to neuroma formation: "When nerve tissue is cut the Schwann
cell-endoneural barrier is disrupted, allowing the axons to regenerate in a disorganized fashion. The
regenerating axons are often surrounded by connective tissue, further disorganizing the regenerate.
If a nerve lies too near the end of the stump . . . it is subject to repeated trauma from pressure, [and]
friction. . . . This leads to increased edema and fibrosis of the nerve, leading to increased sensitivity."
Thus, to prevent the development of amputation neuromas, one must avoid cutting or ligating a
nerve at skin level.
But What Type of Surgical Excision?
Leber and Gosain6 prefer the last of the above options: they recommend dissecting the nerve free
from the surrounding tissue before transection and then placing traction on the nerve while
transection is performed. They note that this method allows the nerve to retract into a bed of healthy
soft tissue away from the surface of the amputated stump. In fact, they consider simple excision to
have as much potential for complication as does ligation.
Growing Support for Surgical Excision Opinions
on the question of ligation versus surgical excision do appear to be shifting. A survey of 149
pediatricians and neonatologists in the United Kingdom revealed that 79% would refer a child with
type B postaxial polydactyly to a hand surgeon, 15% would ligate, and 5% would use excision.9 We
found 3 articles recommending primary surgical excision,6-8 as well as a similar statement in the
recent (2009) American Academy of Pediatrics' textbook, Pediatric Primary Care.10 Another article
advises caution in using ligation because of a "high rate of complications" (even though the
complications referred to were most likely cosmetic).11 Frieden and colleagues5 advise using local
anesthetic and iris scissors. Still, the only prospective study on the subject recommends suture
ligation.2
Our View
We consider necrosis a poorly controllable surgical instrument. We cannot prove the superiority of
local anesthetic and scalpel excision, but while we wait for a trial comparing treatment techniques,
we suggest that clinicians use the latter approach. This obviates the need to perform the procedure
in the operating room while eliminating the risk of infection that is always associated with tissue
necrosis.
References: REFERENCES:
1. Bowman JE, Murray RF Jr. Genetic Variation and Disorders in Peoples of African Origin. Baltimore:
Johns Hopkins University Press; 1990:270-271.
2. Watson BT, Hennrikus WL. Postaxial type-B poly- dactyly. Prevalence and treatment. J Bone Joint
Surg Am. 1997;79:65-68.
3. Cornwall R. Upper limb. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson
Textbook of Pediatrics. 18th ed. Philadelphia: Saunders; 2007:2826-2827.
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To Tie or Not to Tie: The Dilemma of the Supernumerary Digit
Published on Physicians Practice (http://www.physicianspractice.com)
4. Mehlman CT. Upper extremity problems. In: Rudolph CD, Rudolph AM, Hostetter MK, et al, eds.
RudolphÕs Pediatrics. 21st ed. New York: McGraw-Hill; 2003:2449.
5. Frieden IJ, Chang MW, Lee I. Suture ligation of supernumerary digits and ÒtagsÓ: an outmoded
practice? Arch Pediatr Adolesc Med. 1995;149:1284.
6. Leber GE, Gosain AK. Surgical excision of pedunculated supernumerary digits prevents traumatic
amputation neuromas. Pediatr Dermatol. 2003;20:108-112.
7. Heras L, Barco J, Cohen A. Unusual complication of ligation of a rudimentary ulnar digit. J Hand
Surg Br. 1999;6:750-751.
8. Hartzell TL, Taylor H. Traumatic amputation of a supernumerary digit: a 16-year-old boyÕs
perspective of suture ligation. Pediatr Dermatol. 2009;26:100-102.
9. Dodd JK, Jones PM, Chinn DJ, et al. Neonatal accessory digits: a survey of practice amongst
paediatricians and hand surgeons in the United Kingdom. Acta Paediatr. 2004;93:200-204.
10. Trevino JJ, Bakos MA, Janik MP. Neonatal skin. In: McInerny TK, Adam HM, Campbell D, et al, eds.
Pediatric Primary Care. 5th ed. Elk Grove Village, IL: American Academy of Pediatrics; 2009:783. 11.
Rayan GM, Frey B. Ulnar polydactyly. Plast Reconstr Surg. 2001;107:1449-1454.
Source URL: http://www.physicianspractice.com/articles/tie-or-not-tie-dilemma-supernumerary-digit
Links:
[1] http://www.physicianspractice.com/authors/khalid-h-safi-md
[2] http://www.physicianspractice.com/authors/howard-fischer-md
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