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Case Report  |   November 2017
Management of Postaxial Polydactyly in the Neonatal Unit
Author Notes
  • From the Department of Family and Community Medicine at the Dwight D. Eisenhower Army Medical Center in Fort Gordon, Georgia. 
  • Financial Disclosures: None reported. 
  •  *Address correspondence to Nicholas A. Rathjen, DO, Department of Family and Community Medicine, Dwight D. Eisenhower Army Medical Center, 301 E Hospital Rd, Fort Gordon, GA 30905-5740. E-mail: nicholas.a.rathjen.mil@mail.mil
     
Article Information
Neuromusculoskeletal Disorders / Pediatrics
Case Report   |   November 2017
Management of Postaxial Polydactyly in the Neonatal Unit
The Journal of the American Osteopathic Association, November 2017, Vol. 117, 719-721. doi:10.7556/jaoa.2017.138
The Journal of the American Osteopathic Association, November 2017, Vol. 117, 719-721. doi:10.7556/jaoa.2017.138
Abstract

Postaxial type B polydactyly is the presence of a supernumerary digit attached by soft tissue in a pedunculated fashion to the fifth digit. In the present case, a newborn with bilateral postaxial type B polydactyly underwent suture ligation to remove the supernumerary digit, but multiple ligation attempts were required. Ultimately, residual tissue remained bilaterally, but it did not seem to be painful. A comprehensive review of the literature revealed no clear recommendation on treatment options for patients with postaxial polydactyly. Although suture ligation has been common practice, surgical excision is an acceptable option that can be performed in the neonatal unit and may result in fewer complications than suture ligation.

Postaxial polydactyly is the duplication of the fifth digit and includes supernumerary digits that are fully developed with bone and neural tissue (type A) or that are attached only by soft tissue (type B).1 Supernumerary digits should be evaluated with electromagnetic radiography as part of the initial step in the diagnosis of polydactyly.2 Although the exact incidence is not known, to our knowledge, a study suggests that polydactyly is present in 1 in 1000 births in the general population, with a higher incidence of 1 in 150 births in the black population.3,4 Eighty-five percent of cases have a positive family history, and 75% are bilateral.4 Physicians overseeing a neonatal unit will likely encounter polydactyly and be challenged with the task of deciding on a treatment option. This report describes the case of a newborn with bilateral postaxial type B polydactyly and provides a short literature review of treatment options for patients with postaxial polydactyly. 
Report of Case
A black male was born to a 34-year-old gravida 5 para 3 mother via spontaneous vaginal delivery at 39 weeks’ gestational age. The pregnancy and delivery were unremarkable, with Apgar scores of 9 at both 1 and 5 minutes. On examination in the neonatal unit, postaxial type B polydactyly was discovered on both of the newborn's hands. The mother reported that she was born with the same condition and underwent suture ligation as a newborn. She reported that she was left with approximately 2 mm of residual tissue bilaterally, which she denied as bothering her cosmetically or physically. Four days after birth, the newborn underwent suture ligation of both supernumerary digits at the recommendation of the orthopedic surgeon. At a follow-up appointment 1 week later, the left digit had fully necrosed, but the right digit had not. The right digit was ligated again and fell off 9 days later. At a follow-up appointment at age 2 months, the patient was found to have residual tissue bilaterally (approximately 2 mm), which did not appear to cause any discomfort. 
Discussion of Treatment Options
When treating patients with postaxial type B polydactyly, goals include complete removal of excess tissue, prevention of neuroma, minimization of cosmetically displeasing residual tissue, and avoidance of common adverse outcomes (eg, infection, bleeding, complications caused by anesthesia).5 We believe optimization of outcomes requires proper classification of polydactyly into subgroups for which an optimal treatment has been identified. Few studies have documented outcomes of the various treatments for type B polydactyly, and no definitive clinical guidelines have been provided by a major organization. Although suture ligation has been commonly taught to primary care physicians, no evidence-based standard of care for management of type B polydactyly and no clear evidence that suture ligation is the most effective treatment exists, to our knowledge. 
A PubMed literature review using the combination of terms “neonate,” “supernumerary digit,” and “treatment” was conducted. References of relevant articles were also reviewed for potentially important literature. This search revealed 6 cohort studies discussing various treatment modalities for postaxial type B polydactyly, including excision under topical or general anesthesia, suture ligation, and surgical clip ligation. 
The most common treatment for patients with postaxial type B polydactyly is suture ligation, which is typically done in the neonatal unit.1 However, suture ligation may not always be the best management option. One cohort study4 screened 21 newborns (37 supernumerary digits) with postaxial type B polydactyly who underwent suture ligation at the base of the pedicle. This treatment was unsuccessful in 1 newborn, whose digit failed to necrose properly. Twenty-one of the 37 sites (43%) that were reexamined at an average age of 20 months were found to have residual tissue.4 Although suture ligation has been touted as simple, safe, and effective,2,6 limited evidence shows that it can lead to a greater likelihood of incomplete amputation than surgical excision.4 Furthermore, suture ligation may be more likely to lead to painful neuromas than surgical excision; Leber and Gosain5 suggest that the incidence of painful neuroma caused by suture ligation may be higher than previously thought, resulting from underreporting by patients or their guardians. These unsatisfactory outcomes affect quality of life and require additional, more elaborate procedures to resolve. Incomplete amputation with ligation is more likely when the base of the supernumerary digit is greater than 2 mm.7 
Surgical excision for patients with type B polydactyly is another option for the removal of supernumerary digits. Research has shown that this treatment option can be more advantageous than suture ligation in the neonatal unit. A prospective study evaluated the results of surgical excision of supernumerary digits in patients with postaxial type B polydactyly using topical anesthesia in 11 consecutive infants (15 supernumerary digits) 2 to 3 days after birth. No complications were reported, and the site of excision was “barely seen” 1 year after the procedure.1 A retrospective study8 examined 32 patients (53 supernumerary digits) with type A or type B polydactyly who underwent oval excision with general anesthesia at an average age of 8.6 months (range 0-10 years). Of the 32 patients, minor complications developed in 4 patients (ie, hypertrophic scar and superficial wound infection), and 1 patient had a painful neuroma that needed a revision 3 years later. Of the 20 patients seen at follow-up (a mean of 4.9 years after the excision), 18 (90%) had a flat scar and 2 (10%) had painful residual tissue.8 Overall satisfaction was 89 out of 100 (100 being the most satisfied).8 A case series7 examined 10 patients (13 supernumerary digits) ranging in age from 1 week to 13 years who had previously undergone suture ligation that resulted in complications, including painful neuromas and incomplete excisions. All patients were successfully treated with amputation of the residual tissue and proximal ligation of the supernumerary digit nerve. Another case series5 divided patients with postaxial type B polydactyly into 2 groups to be treated for supernumerary digits or their sequelae. One group was made up of 3 patients with traumatic amputation neuromas (5 traumatic amputation neuromas combined) caused by suture ligation of accessory digits in infancy, and the second group consisted of 6 patients (12 supernumerary digits) presenting with untreated postaxial type B polydactyly. Both groups underwent elliptical surgical excision under general anesthesia, and at a 6-year follow-up, no complications occurred in either of the patient groups. 
Mullick and Borschel7 stated that surgical excision was preferable over suture ligation in any digit with a bony or ligamentous attachment or presence of a wide base to prevent incomplete amputation or painful neuroma. This procedure can be done in the neonatal unit under topical or local anesthesia, but they recommend that infants older than 3 months be referred for excision using general anesthesia.7 Katz and Linder1 also recommend surgical excision using topical anesthesia rather than suture ligation. Leber and Gosain5 argued for surgical excision to prevent painful neuromas, describing a more complex procedure using general anesthesia. In 1995, Frieden et al9 argued that there is little evidence to support the rationale behind suture ligation and that it should be abandoned because of variation in supernumerary digit size, possible presence of bone, and the increased risk of infection, scarring, and incomplete removal. They recommended that supernumerary digits be infiltrated with a local anesthetic at the base, and the lesion should be surgically excised via sterile scissors, which would minimize the potential for infection, ongoing inflammation, pain, and slow healing that may occur after suture ligation.9 
Another option for removing supernumerary digits in patients with postaxial polydactyly is surgical clip ligation, which is similar to suture ligation. A retrospective study10 that examined 132 infants with extra digits with a flat base (<6 mm) who underwent surgical clip ligation found no immediate complications; however, 7% of patients had painful neuromas that required surgical revision. 
Conclusion
Surgical excision using local or topical anesthesia is often preferable to suture ligation for the removal of supernumerary digits with a base between 2 mm and 6 mm. Suture ligation is as effective as surgical excision on lesions smaller than 2 mm. Contraindications to treatment by primary care physicians in the neonatal unit include wide-based, bony, or ligamentous attachments. Additional prospective studies comparing treatment techniques for patients with postaxial polydactyly are needed. 
References
Katz K, Linder N. Postaxial type B polydactyly treated by excision in the neonatal nursery. J Pediatr Orthop. 2011;31(4):448-449. doi: 10.1097/BPO.0b013e31821addb6 [CrossRef]
Zitelli BJ, Davis HW. Atlas of Pediatric Physical Diagnosis. 5th ed. St. Louis, MO: Mosby; 2007:419-420.
Finley WH, Gustavson KH, Hall TM, Hurst DC, Barganier CM, Wiedmeyer JA. Birth defects surveillance: Jefferson county, Alabama, and Uppsala county, Sweden. South Med J. 1994;87(4):440-445. [CrossRef] [PubMed]
Watson BT, Hennrikus WL. Postaxial type-B polydactyly: prevalence and treatment. J Bone Joint Surg Am. 1997;79(1);65-68. [CrossRef] [PubMed]
Leber GE, Gosain AK. Surgical excision of pedunculated supernumerary digits prevents traumatic amputation neuromas. Pediatr Dermatol. 2003;20(2):108-112. [CrossRef] [PubMed]
Cornwall R. Upper limb. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, PA: Saunders; 2007:2826-2827.
Mullick S, Borschel GH. A selective approach to treatment of ulnar polydactyly: preventing painful neuroma and incomplete excision. Pediatr Dermatol. 2010;27(1):39-42. doi: 10.1111/j.1525-1470.2009.01071.x [CrossRef] [PubMed]
Singer G, Thein S, Kraus T, Petnehazy T, Eberl R, Schmidt B. Ulnar polydactyly: an analysis of appearance and postoperative outcome. J Pediatr Surg. 2014;49(3):474-476. doi: 10.1016/j.jpedsurg.2013.06.029 [CrossRef] [PubMed]
Frieden IJ, Chang MW, Lee I. Suture ligation of supernumerary digits and ‘tags’: an outmodel practice? 1995;149(11):1284.
Mills JK, M, Oishi SN. Ulnar polydactyly: long-term outcomes and cost-effectiveness of surgical clip application in the newborn. Clin Pediatr (Phila). 2014;53(5):470-473. doi: 10.1177/0009922813514479 [CrossRef] [PubMed]