Double thumb

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Classification according to ICD-10
Q69.1 Accessory thumb (s)
ICD-10 online (WHO version 2019)
Double thumb on the left hand
Double thumb on the right front paw of a cat

The double thumb (synonyms: radial polydactyly, accessory thumb) is the most common malformation of the human hand. This is a sub-form of polydactyly , which in turn is assigned to the numerical hand malformations. A double thumb usually occurs in isolation, but can also be found in a syndrome with other malformations.

clinic

The appearance of the double thumb is very variable and ranges from a slight widening of the thumb distal phalanx to the formation of two or even more thumbs. The spectrum of possible forms of the additional thumb extends from a small, functionless appendage to a fully developed, functional thumb with all associated anatomical structures such as tendons and muscles. The accessory thumb can have two or three limbs.

classification

The most widespread is the classification published by Wassel in 1969 and named after him. A prerequisite for the correct classification is the preparation of an X-ray.

Classification of radial polydactyly according to Wassel (1969)
Type Malformation frequency
I. End link forked 02%
II End link created twice 15%
III Basic link forked, end link double 06%
IV Base link and end link created twice 43%
V Metacarpals forked, base and terminal phalanx created twice 10%
VI Metacarpals, base and distal phalanx created twice 04%
VII Radial polydactyly with tripartite thumb (metacarpal I, solitary or double) 20%

Tuch (1977), Wood (1978) and Horii et al. (1997) published modifications of the Wassel classification taking into account the shape, number of links and type of connection between the two thumbs. The current modification was Zuidam et al. 2008, which also takes into account tripartite and hypoplastic thumb rays and triple thumbs.

therapy

The treatment of the double thumb is performed exclusively surgically and serves to improve function and aesthetics. The best age for an operation is between 8 and 12 months of age. Here the smaller ( hypoplastic ) thumb on the spoke side ( radial ) is removed. Type V according to Wassel is a special case. In this case, the connection of the hypoplastic, accessory thumb ray to the wrist is more pronounced than that of the elbow, but well formed thumb ray. Therefore, after removing the spoke-side thumb, the elbow-side thumb is moved onto the spoke-side metacarpal base.

Depending on the type of double thumb, a number of other corrections may be necessary in addition to removing the accessory thumb, such as a narrowing of the bone, reconstruction of the collateral ligament, fixation with Kirschner wire , shifting the extensor tendon from the accessory thumb to the remaining thumb, re- insertion of detached thumb ball muscles, bony ones Correction if there is an axis deviation, Z, rotation or swivel flap plastic if the first interfinger space is too narrow.

If both thumbs are of the same size and hypoplastic, bilhaut Cloquet surgery is indicated . Here, the third lying between the two thumbs is removed and the bones and soft parts of both are combined into a new thumb using cerclages and sutures . Above all, it is important that the joint surfaces are brought together steplessly and that the nail fold and nail bed are microsurgical sutures.

If there is a tripartite thumb, the excess phalanx (middle phalanx) is removed. If there is an extremely rare triple thumb, the most pronounced thumb is used and the other two removed.

Complications

Possible complications after surgery for radial polydactyly are restricted movement and / or axial deviation of the remaining thumb, joint instability and nail deformity. Restriction of movement of the thumb after the operation can also be due to dysplasia of the thumb saddle joint in the course of the malformation . In many cases further corrective surgery is required.

literature

  • M. Strassmair, K. Wilhelm, R. Hierner: Congenital malformations of the hand. In: A. Berger, R. Hierner (Eds.): Plastic surgery, Volume IV: Extremities. Springer, Berlin / Heidelberg 2009, ISBN 978-3-540-00144-7 .
  • H. Piza-Katzer, A. Wenger: Congenital malformations of the hand. In: H. Towfigh, R. Hierner, M. Langer, R. Friedel (Eds.): Handchirurgie. Springer, Berlin / Heidelberg 2011, ISBN 978-3-642-11757-2 .

Individual evidence

  1. ↑ H. Piza-Katzer, A. Wenger: Congenital malformations of the hand. In: H. Towfigh, R. Hierner, M. Langer, R. Friedel (Eds.) Handchirurgie. Springer, Berlin / Heidelberg 2011, ISBN 978-3-642-11757-2 , pp. 514-516.
  2. ^ A b T. Ogino, S. Ishii, S. Takahata, H. Kato: Long-term results of surgical treatment of thumb polydactyly . In: The Journal of Hand Surgery . tape 21 , no. 3 , May 1996, pp. 478-486 , doi : 10.1016 / S0363-5023 (96) 80366-2 , PMID 8724483 .
  3. ↑ a b c d A. K. Martini: Congenital malformations. In: Martini, AK (Ed.): Orthopedics and orthopedic surgery: elbow, forearm, hand. Thieme, 2003, ISBN 3-13-126211-7 , p. 192.
  4. ↑ HD Wassel: The results of surgery for polydactyly of the thumb. A review . In: Clinical Orthopedics and Related Research . tape 64 , June 1969, p. 175-193 , PMID 4894526 .
  5. ↑ U. Lanz, R. Schmitt: Imaging diagnostics of the hand. Thieme, Stuttgart 1996, ISBN 3-7773-1177-4 , p. 106.
  6. ^ BA Tuch, EB Lipp, IJ Larsen, LH Gordon: A review of supernumerary thumb and its surgical management . In: Clinical Orthopedics and Related Research . No. 125 , June 1977, p. 159-167 , PMID 880759 .
  7. ^ VE Wood: Polydactyly and the triphalangeal thumb . In: The Journal of Hand Surgery . tape 3 , no. 5 , September 1978, p. 436-444 , PMID 701767 .
  8. ↑ E. Horii, R. Nakamura, M. Sakuma, T. Miura: Duplicated thumb bifurcation at the metacarpophalangeal joint level: factors affecting surgical outcome . In: The Journal of Hand Surgery . tape 22 , no. 4 , July 1997, p. 671-679 , doi : 10.1016 / S0363-5023 (97) 80127-X , PMID 9260625 .
  9. ↑ J. Michiel Zuidam, Ruud W. Selles, Michael Ananta, Jetteke Runia, Steven ER Hovius: A classification system of radial polydactyly: inclusion of triphalangeal thumb and triplication . In: The Journal of Hand Surgery . tape 33 , no. 3 , March 2008, p. 373-377 , doi : 10.1016 / j.jhsa.2007.12.012 , PMID 18343293 .
  10. ↑ DJ Townsend, EB Lipp, K. Chun, K. Reinker, B. Tuch: Thumb duplication, 66 years' experience - a review of surgical complications . In: The Journal of Hand Surgery . tape 19 , no. 6 , November 1994, pp. 973-976 , doi : 10.1016 / 0363-5023 (94) 90099-X , PMID 7876498 .