DOI: 10.5152/TurkJPlastSurg.2016.1939
Coexistence of a Bifid Median Nerve and
Persistent Median Artery in a Pediatric Trauma Case Bir Pediatrik Travma Hastasinda Bifid Median Sinir ve Persistan Median Arter Birlikteliği
Nesibe Sinem Çiloğlu, Alpay Duran, Hasan Büyükdoğan, Ahmet Kürşat Yiğit, İhsan Türkmen
Clinic of Plastic, Reconstructive and Aesthetic Surgery, Haydarpasa Numune Training and Research Hospital, İstanbul, Turkey
142
Abstract Öz
Knowledge regarding the variations of median nerve branching is particularly important in surgical decompression and trauma cases.
A bifid median nerve together with a palmar-type median artery is a rare anatomical variation. The importance of a persistent median artery lies in the fact that the one with a large caliber may lead to an early compression of the median nerve in the carpal tunnel in pa- tients. In the presence of a persistent median artery, surgeons must be aware regarding possibility of additional median nerve anomalies.
Keywords: Bifid median nerve, median artery, trauma, pediatric
Median sinirin varyasyonlarının bilinmesi özellikle cerrahi dekom- presyon ve travma olgularında önemlidir. Palmar tip median arter ve bifid median sinir birlikteliği nadir bir anatomik varyasyondur.
Regrese olmayıp varlığına devam edecek median arter ile ilgili en önemli sorun, büyük kalbireli arterlerin karpal tünel hastalarında median sinirin erken kompresyona yol açabilmeleridirler. Persistan median arter varlığında cerrahlar ilave median sinir anomalisi ihti- malini akılda tutmalıdırlar.
Anahtar Sözcükler: Bifid median sinir, median arter, travma, pediatrik
Correspondence Author/Sorumlu Yazar: Alpay Duran, MD E-mail/E-posta: dr.alpayduran@hotmail.com
©Copyright by 2016 Turkish Society of Plastic Reconstructive, and Aesthetic Surgery - Available online at www.turkjplastsurg.com.
©Telif Hakkı 2016 Türk Plastik Rekonstrüktif ve Estetik Cerrahi Derneği - Makale metnine www. turkjplastsurg.com web sayfasından ulaşılabilir.
INTRODUCTION
Knowledge regarding variations of median nerve branching is particularly important in surgical decompression and trauma cases. A bifid median nerve with a persistent median artery is a rare anatomical variation. The importance of a persistent median artery lies in the fact that a large caliber artery may lead to an early compression of the median nerve in the carpal tunnel. Furthermore, the bifid median nerve may be the cause of the carpal tunnel syndrome because of its relatively higher cross-sectional area compared with a non-bifid median nerve. It is possible to avoid the advertent injury to the median nerve during surgery by recognizing the anatomy and its variations.
CASE PRESENTATION
A 12-year-old male presented with a 5 cm long laceration of his left wrist. After explaining the purpose of the study, written informed consent was obtained from the parents of the patient. The patient complained of the loss of sensation in his index and middle fingers.
During surgical exploration, a bifid median nerve and persistent median artery were found. A bifid median nerve had two unequal branches. The radial division was larger than the ulnar division of the median nerve, and a large persistent median artery was identified between them (Figure 1). Median artery and the ulnar branch of the median nerve were completely lacerated, while the radial branch of the median nerve was partially lacerated. Ulnar and radial arteries were observed intact in the performed exploration. It was observed that the median artery joined the superficial palmar arch. Epineural repair of the branches of the median nerve were performed, and the carpal tunnel was prophylactically released.
DISCUSSION
The classic pattern describes the division of the median nerve into five branches at the distal end of the flexor retinaculum. However, a high division of the median nerve proximal to the carpal tunnel, also known as a bifid median nerve, is an anatomical variation.1 Lanz
Case Report / Olgu Sunumu
Received/Geliş Tarihi: 13.12.2014 Accepted/Kabul Tarihi: 12.10.2015
classified the variations of the course of the median nerve into four groups. Group I comprises thenar branch variations, Group II includes accessory branches at the distal carpal tun- nel, Group III encompasses high median nerve divisions. and Group IV includes accessory branches proximal to the carpal tunnel. Group III may be further divided into three subgroups according to the absence of a median artery (Group III a), presence of a median artery (Group III b), or an accessory lum- brical muscle (Group III c) between the two branches of the proximally divided median nerve.2
The median artery is a transitory vessel that represents the arterial axis of the forearm during the early embryonic life. It normally regresses after the second embryonic month.3 The median artery may persist in adult life in two different pat- terns, palmar and ante brachial, based on their vascular terri- tory. The ante brachial pattern, because of its high incidence in adult forearms, may be considered as a normal feature rath- er than as a variation. In contrast, the palmar pattern appears with a lower incidence in adult forearms.4
The prevalence of bifid median nerves and persistent median arteries in the general population is poorly delineated. The re- ported prevalence of a bifid median nerve ranges from 5% to
15.4%, and persistent median arteries have a prevalence that range from 0.6% to 23% in wrists of carpal tunnel patients, adult cadavers, or healthy individuals.5-14 The most common association with a bifid median nerve is a persistent medi- an artery. Absolute percentages of persistent median arteries or bifid median nerves may vary with the techniques used to detect them.
Median nerve variations are well described because of their diagnostic and surgical importance. The occurrence of a bifid median nerve has been widely reported in the literature, and it is observed most commonly during surgical interventions or anatomical dissection and rarely during preoperative so- nographic or magnetic resonance imaging (MRI). In a series of 913 carpal tunnel patients who were operated and dissected, Tountas et al.15 discovered the coexistence of the bifid median nerve and persistent median artery in eight cases. In anoth- er study involving 294 hands, a single case of a bifid medi- an nerve without a median artery was reported.12 In a recent study, 17 cases of the coexistence of a bifid median nerve and persistent median artery have been reported in 1026 wrists of manual workers.5 Stancić et al.16 reported that 48 hands revealed standard anatomy while examining 100 hands, and there was only one case with the coexistence of a bifid medi- an nerve and median artery. In a series of 110 patients who underwent open carpal tunnel release, Beris et al.17 reported two such cases (Table I).
In the literature, there are several studies that use imaging techniques. The coexistence of a bifid median nerve and persistent median artery in the carpal tunnel of four patients was identified in a study where 194 wrists were evaluated using MRI.13 Gassner et al.14 reported 10 cases of a bifid me- dian nerve and persistent median artery in 100 wrists.14 In another study reporting the coexistence of a bifid median nerve and persistent median artery that was examined using USG, the carpal tunnel syndrome patients and control group were compared and it was reported that the existence of a bifid median nerve is not a risk factor for the carpal tunnel syndrome.18 In most studies, patients referred to a physician for the evaluation of suspected carpal tunnel syndrome.
Only three cases of the coexistence of a bifid median nerve and persistent median artery have been previously reported among trauma patients.19,20
Turk J Plast Surg 2016; 24(3): 142-4 Çiloğlu et al / Bifid Median Nerve and Persistent Median Artery
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Figure 1. Perioperative view of the case
Table I. Incidence of the coexistence of BMN and PMA in previously reported studies
Reference/Year Population studied Tecchnique Coexistence of BMN and PMA/Wrists Percentage
Tountas al.15 CTS patients Intraoperative 8/913 0.87%
Stancic et al.16 CTS patients Intraoperative 1/100 1%
Ahn et al.12 CTS patients Intraoperative 0/294 0%
Gassner et al.14 Healthy controls Ultrasound 10/100 10%
Beris et al.17 CTS patients Intraoperative 2/110 1.8%
Pierre-Jerome et al.19 Patients MR 4/194 2%
Walker et al.5 Manual workers Ultrasound 17/1026 1.6%
BMN: bifid median nerve; PMA: persistent median artery
However, a bifid median nerve may cause the carpal tunnel syndrome because of its relatively higher cross-sectional area compared with a non-bifid median nerve. In addition, a per- sistent median artery of a large caliber may further lead to an early compression of the median nerve in the carpal tunnel.21 Therefore, in hand trauma cases and carpal tunnel release pa- tients, these anatomical variations should be considered.
CONCLUSION
In the presence of persistent median artery, surgeons must be aware regarding the possibility of additional median nerve anomalies. Careful exploration is necessary to not overlook the variations of the median nerve and artery. Moreover, the prophylactic release of the carpal tunnel should be consid- ered because of the increased predisposition to nerve com- pressions.
Informed Consent: Written informed consent was obtained from pa- tients’ parents who participated in this case.
Peer-review: Externally peer-reviewed.
Author Contributions: Concept - N.S.Ç., A.D.; Design - A.D., N.S.Ç.; Su- pervision - N.S.Ç.; Resources - A.D.; Materials - N.S.Ç.; Data Collection and/or Processing - H.B., A.K.Y., İ.T.; Analysis and/or Interpretation - N.S.Ç., A.D., H.B., İ.T.; Literature Search - A.D., A.K.Y.; Writing Manuscript - N.S.Ç., A.D., H.B.; Critical Review - N.S.Ç.
Conflict of Interest: No conflict of interest was declared by the au- thors.
Financial Disclosure: The authors declared that this study has re- ceived no financial support.
Hasta Onamı: Yazılı hasta onamı bu olguya katılan hastanın ailesin- den alınmıştır.
Hakem Değerlendirmesi: Dış bağımsız.
Yazar Katkıları: Fikir - N.S.Ç., A.D.; Tasarım - A.D., N.S.Ç.; Denetleme - N.S.Ç.; Kaynaklar - A.D.; Malzemeler - N.S.Ç.; Veri Toplanması ve/veya İşlemesi - H.B., A.K.Y., İ.T.; Analiz ve/veya Yorum - N.S.Ç., A.D., H.B., İ.T.;
Literatür Taraması - A.D., A.K.Y.; Yazıyı Yazan - N.S.Ç., A.D., H.B.; Eleştirel İnceleme - N.S.Ç.
Çıkar Çatışması: Yazarlar çıkar çatışması bildirmemişlerdir.
Finansal Destek: Yazarlar bu çalışma için finansal destek almadıkla- rını beyan etmişlerdir.
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Turk J Plast Surg 2016; 24(3): 142-4 Çiloğlu et al / Bifid Median Nerve and Persistent Median Artery
