Case reports

Brachial Artery Entrapment �9 Compression by the Supracondylar Process

Hafid Talha, MD, Bernard Enon, MD, Jean-Michel Chevalier, MD, Philippe L 'Hos te , MD, Jean Pillet, MD, Angers', France

Ischemia occurring during hyperextension of the upper limb In a 25-year-old woman led to the discovery of a supracondylar spur responsible for compression of the brachial artery with anomalous insertion of the pronator teres muscle. Resection of all abnormal structures provided immediate relief of symptoms. When atypical arte- rial symptoms of thoracic outlet syndrome occur in the upper limb, the brachlal ar- tery entrapment syndrome should be considered. (Ann Vasc Surg, 1986, 1, 479-482).

KEY-WORDS : Brachlal Artery. - - Supracondylar Process.

The supracondylar process of the humerus is a rare congenital anomaly, reported for the first time by Tiedman in his Tabulae Arteriarum in 1822. In 1889, Testut described a bony spur , arising from the medial aspect of the humerus at a point equidis- tant between the medial and anterior borders of the humerus. It is separated from the most advanced part of the medial epicor~dyle by 59 mm and from the most distal aspect of the lateral condyle by 71 ram. Its average length ranges between 5 and 8 ram, its form that of a flattened pyramid from

From the Service de Chirurgie Vasculaire et Thon~cique et Service de Radiologie, Centre Hospimlier Regional, Angers, France.

Re(~rint requests ." B. Enon, MD, Service de Chirurgie Vas- cutaire et Thoracique, Centre Hospitalier Rdgional, 49040 Angers Cedex, France.

back to front, or that of a hook.. . ,,. This spur is usually associated with a proximal expansion of the pronator teres muscle which covers the brachial ar- tery [I].

The anomaly ,,vhich results in vascular and nerve compression syndromes at the level of the elbow, has been reported only rarely [2, 3].

CASE R E P O R T

A 25-year-old woman working as a farm-hand was ad- mitted for exertional ischemia of the right hand of six yea~ duration. Symptoms included distal paresthesia des- cribed as a sensation of - cold and numb ,~ fingers while carrying loads with the elbow in hyperextension. Symp- toms regressed as soon as the effort was discontinued. At first, the diagnosis of thoracic outlet syndrome was sugges- ted. Doppler wave analysis and dynamic angiography doc-

ANNAI.S OF 480 BR,-'I CHL~.L A R T E R Y E N T R A P M E N T VASCUI,AR NURGER'~"

Fig. 1. - - Brachi~l artery angiogram : When extension of elbow = 0 ~ brachial artery Is normat.

Fig. 2. - - Brachlal angiog~am : When elbow is hypere~ten- deal to 10 ~ medial deviation and narrowing of brachial artery Occur ,

umented moderate, stress-related narrowing of the arterial and venous subclavian and axillary vessels. Because of in- tense edema of the hand, following strenuous effort, the patient underwent resection of the first rib without relief of symptoms.

Upon her second adrnission, it was found that 10 ~ of hy- perextension obliterated the patient's radial pulse. Oblit- eration of flow by hyperextension was confirmed by Dop pler wave analysis. Angiography showed that the brachial artery shifted medially when the elbow was overextended, and the angiogram documented an extrinsic compression at the level of the joint (Fig. 1). This compression disap- peared as soon as the elbow was flexed (Fig. 2).

At surgical exploration, once the superficial brachial fascia was incised, a wide muscular sheet, comprised of longitudinal lateral fibers united to oblique fibers, was found to arise along the medial aspect of the humerus, to a point 6 cm above the medial epicondyle (Fig. 3). The brachiaI artery was seen only after division of the muscu- lar fascicles which crossed the brachial vessels and median nerve from back to front inserting on a small bony process located on the medial aspect of the humerus (Fig. 4). The brachial artery ran a double z i~ag curved course. The concavity of the proximal curve was anterior, centered on the bony prominence, while the concavity of the second curve was posterior, following the articular contour of the elbow. Flow stopped in the brachial artery when the elbow was hyperextended.

VOLUME 1 N o 4 - 1986 BR.4 CtIL4 L A R ~'ER Y E N T R A P M E N T 481

Fig. 3, - - Operative photo showing anomalous superior Fig. 4. - - Operative photo showing fibrous Insertion of pro- fibers of pronator fores muscle (arrow). nator teres muscle on supracondylar process (arrow).

Treatment consisted in extraperiosteal resection in the cartilaginous supracondylar process, after division of the muscular fibers of the pronator teres which were inserted onto it. Following this procedure, the radial pulse was clearly detectable when the elbow was hyperextended.

The post-operative course was uneventful, Six months later all clinical signs had disappeared.

DISCUSSION

The presence of supracondylar process is rare. Terry [4] reported an incidence of about 1 % in the European population. Poirier discovered this ano- maly in three of 247 post-mortem specimens [5]. The equivalent in most mammals (marsupials, rodents. and lower monkeys) forms the roof of the supracon- dylar foramen [4]. Although there are many old ana- tomic studies [1, 4, 5], clinical studies are rare. In 1966, Kessel and Rang [2] repor ted a case of compression of the ulnar artery arising from a high- flying division of the brachial artery. In 1977, Thom-

sen [3] published 13 cases of compression of the me- dian and ulnar nerves associated with the supracon- dylar process.

Compression is due to an anomalous attachment of the pronator teres muscle which is inserted on the supracondylar process above its usual point of inser- tion. This was evident in our patient whose brachial artery pinched between the elbow joint and the anom- alous fibers of the pronator teres when her albow was placed in hyperextension. The brachial vein, the median and occasionally the ulnar nerves may be equally involved [3]. The symptoms and dynamic character of onset may be misleading and suggestive of a thoracic outlet syndrome. In the absence of char- acteristic signs of a thoracic outlet syndrome, the diagnosis of brachial artery entrapment by the su- pracondylar process should be considered.

Diagnosis of supracondylar spur may be suggested clinically when the process is large enough to be pal- pated on the medial aspect of the arm. Obliteration

ANNALSOF 482 BR.4 C H ~ l. AR TER Y ENTRA PMENI" VASCULAR SURGERY

of the radial pulse when the elbow is hyperextended fully is also strongly suggestive. When the supracon- dylar process is ossified, it can be seen on plain x-ray films. This was not our case. Dynamic Doppler and angiographic studies may help x~:ith diagnosis.

Treatment consists of division of the anomalous insertion of the pronator teres muscle. Resection of the supracondylar process should be extraperiosteal in order to preclude regrowth. Once freed, full ex- tension no longer provokes neurovascular compres- sion.

Finally, investigation of a supracondylar process should be routine when an atypical neurovascular compression syndrome is found in the upper limb. Clinical examination and simple diagnostic procedu- res should easily lead to correct diagnosis.

REFERENCES

!. TESTU [.. L'apophyse sus-dpitrochlOcnne considdrde au point de vue chirurgical. Bull Soc Chit 1889. 330-335.

2. KESSEL L, RANG M. Supracondylar spur of the humerus. J Bone Joint Surg 1966 ; 38 B-4 : 765-769.

3. THOMSEN B. Processus supra-condyloidea humeri with concomitant compression of the median nerve and the ulnar nerve. Acta Orthop Scand 1977 : 48 : 391-393.

4. TERRY RJ. On the racial distribution of the supraeondytoid variation. A m J Phys Amhropo l 1930 : I4 : 459-462.

5. POIRIER P. Anatornie humaine "rome I (2 ~ dd). Paris : Mas- son, 1901 : 4a8.

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