Linburg–Comstock syndrome
| Linburg–Comstock syndrome | |
|---|---|
 Linburg and Comstock syndrome is seen as a tendinous connection (green) between flexor pollicis longus (purple) and flexor digitorum profundus (yellow). | |
| Classification and external resources | |
| Specialty | Orthopedic surgery, plastic surgery |
Linburg–Comstock syndrome is an abnormal tendinous connection between the flexor pollicis longus and the flexor digitorum profundus of the index, the middle finger or both. It is an anatomical variation in human, which may be viewed as a pathology if causes symptoms. It was recognised as early as the 1800s, but was first described by Linburg and Comstock in 1979.[1]
Structure
Development
Linburg–Comstock syndrome results from phylogenetic differences between human and non-human primates. Phylogenetically, the flexor pollicis longus and the flexor digitorum profundus both originate from a common mesodermal mass.[2] In non-human primates, there is only one flexor muscle for all the fingers, whereas in humans, the flexor pollicis longus becomes distinct.[3] Linburg–Comstock syndrome may be viewed as an evolutionary persistent structure.
Anatomy
Multiple types of the connection between the flexor pollicis longus and the flexor digitorum profundus were described:[4]
- A tendinous connection between the flexor digitorum profundus of the index to the flexor pollicis longus
- A muscle with a bifurcated (split into two) tendons for the thumb and index finger
- A common muscle with five tendons for the thumb and the long fingers
Signs and symptoms
Although Linburg–Comstock syndrome remains asymptomatic, a number of case reports suggested that symptoms could develop after a forceful extension of the index finger with the thumb in a flexed position.[5][6] Symptoms also develop from heavy and repetitive use of the wrist and forearm and can also develop in those who require fine and independent functionality of the fingers, such as musicians.[5][6]
This abnormality is clinically evident when the patient is unable to flex the thumb without flexing the distal interphalangeal joint of the index or middle finger or vice versa.
Flexor tenosynovitis is a common finding in the patients with Linburg–Comstock syndrome. Another hypothesis is that anatomical variations, which in this case is an additional tendon slip, may act as space-occupying lesions and potentially contribute to carpal tunnel syndrome.[7]
Epidemiology
This variant occurred bilaterally (in both hands) in 14% and unilaterally in 31% (either in left or right hand) out of 194 patients as reported by the original study.[1] Four cases were responsible for chronic tenosynovitis.[1]
Diagnosis and treatment
The examiner passively restricts the flexion of the fingers while the examinee attempts to actively flex the thumb.[8] A positive test is marked by restricted active thumb flexion with pain or cramping discomfort in the palmar and radial sides of the distal (lower) forearm or wrist.[8] The magnetic resonance imaging (MRI) can confirm and localise Linburg and Comstock syndrome.[8] As reported by Karalezli, magnetic resonance imaging was performed on all patients diagnosed with positive test, and there were tendinous connection in all cases.[9]
Surgery may be performed by excising or splitting the tendinous connection to form two separate tendons, depending on the nature of the connection.[10] Muscle belly associated with the symptoms may also be removed.[2]
References
- 1 2 3 Linburg, R. M.; Comstock, B. E. (1 January 1979). "Anomalous tendon slips from the flexor pollicis longus to the flexor digitorum profundus". The Journal of Hand Surgery 4 (1): 79–83. ISSN 0363-5023. PMID 759509.
- 1 2 Slater, R. R. (1 August 2001). "Flexor tendon anomalies in a patient with carpal tunnel syndrome". Journal of Hand Surgery (Edinburgh, Scotland) 26 (4): 373–376. doi:10.1054/jhsb.2001.0613. ISSN 0266-7681. PMID 11469843.
- ↑ "Failure of Flexor Pollicis Longus Repair Caused By Anomalous Flexor Pollicis Longus to Index Flexor Digitorum Profundus Interconnections: A Case Report – Journal of Hand Surgery". www.jhandsurg.org. Retrieved 2016-02-13.
- ↑ Spaepen, D.; De Marteleire, W.; De Smet, Luc (1 October 2003). "Symptomatic Linburg–Comstock syndrome: a case report". Acta Orthopaedica Belgica 69 (5): 455–457. ISSN 0001-6462. PMID 14648957.
- 1 2 "The Linburg Comstock anomaly: A case report". www.sciencedirect.com. Retrieved 2016-02-13.
- 1 2 Furukawa, Kayoko; Menuki, Kunitaka; Sakai, Akinori; Oshige, Toshihisa; Nakamura, Toshitaka (1 January 2012). "Linburg-comstock syndrome: a case report". Hand Surgery 17 (02): 217–220. doi:10.1142/S0218810412720197. ISSN 0218-8104.
- ↑ Slater, R. R (1 August 2001). "Flexor tendon anomalies in a patient with carpal tunnel syndrome". The Journal of Hand Surgery: British & European Volume 26 (4): 373–376. doi:10.1054/jhsb.2001.0613.
- 1 2 3 Yoon, Hong-Kee; Kim, Chang-Hyun (1 September 2013). "Linburg-Comstock syndrome involving four fingers: a case report and review of the literature". Journal of plastic, reconstructive & aesthetic surgery: JPRAS 66 (9): 1291–1294. doi:10.1016/j.bjps.2012.12.032. ISSN 1878-0539. PMID 23379987.
- ↑ Karalezli, Nazım; Karakose, Serdar; Haykir, Rahime; Yagisan, Nihan; Kacira, Burkay; Tuncay, Ibrahim. "Linburg–Comstock anomaly in musicians". Journal of Plastic, Reconstructive & Aesthetic Surgery 59 (7): 768–771. doi:10.1016/j.bjps.2006.01.003.
- ↑ Badhe, S.; Lynch, J.; Thorpe, S. K. S.; Bainbridge, L. C. (1 September 2010). "Operative treatment of Linburg–Comstock syndrome". Bone & Joint Journal 92–B (9): 1278–1281. doi:10.1302/0301-620X.92B9.23577. ISSN 2049-4394. PMID 20798448.