Elbow canal syndrome Elbow canal syndrome is a chronic injury of the ulnar nerve in the ulnar nerve sulcus of the elbow, also known as delayed ulnar neuritis in the past, has been clinically recognized for more than 100 years, is more common, and is a disease of the bone and trauma department. Common causes: elbow valgus can develop after decades in mild cases and within a year in severe cases. Ulnar nerve subluxation, fracture of the humeral epicondyle, if the fracture block is displaced downward, the ulnar nerve can be compressed; traumatic ossification, the elbow joint is the most prone to traumatic ossification myositis. Clinical manifestations: numbness or tingling, weakness of the little finger to the palm and inflexible finger retraction, thickening or mass at the ulnar nerve groove, etc.; ulnar nerve anterior surgery is the basic treatment method. After surgery, normal sensation can be restored more quickly, but it is difficult to restore the normal volume of the atrophied muscles. Symptoms and signs 1.Abnormal sensation of the ulnar side of the dorsal hand, the small fissure, the little finger and the ulnar side of the ring finger occurs first, usually as numbness or tingling. 2, after the occurrence of sensory abnormalities for a certain period of time black can appear small finger to palm weakness and finger retraction inflexibility. 3.Examination shows atrophy of the interosseous muscle and interosseous muscle of the hand, and orthogonal claw-like deformity of the ring and little finger, hyperalgesia of the skin in the aforementioned area, positive paperclip test and positive Tinel’s sign at the ulnar nerve sulcus. 4.Electrophysiological examination found that the conduction velocity of ulnar nerve under the elbow was slowed, and the electromyography of interosseous muscle and interosseous muscle was abnormal. 5.Evidence of underlying disease such as elbow valgus, thickening of the ulnar nerve sulcus with a black mass, X-ray showing localized displaced bone or abnormal ossification, etc. Disease etiology Although various structural and morphological abnormalities of the elbow canal can cause the ulnar nerve to be compressed, the following causes are more common in clinical practice. 1. Elbow valgus This is the most common cause. Injury to the supracondylar humerus or the epiphysis of the humeral condyle in early childhood can lead to elbow valgus deformity, at which time the ulnar nerve is pushed to the medial side to increase the tension, and the tension is even higher when the elbow joint is flexed, so that repeated friction in the elbow canal can produce chronic traumatic inflammation of the ulnar nerve or degenerative elbow valgus in mild cases, which can develop after several decades, and in heavy cases within a year. 2, ulnar nerve subluxation These are due to congenital shallow ulnar nerve groove or the top of the elbow canal fascia, ligament structure relaxation, the ulnar nerve is easy to slide out of the ulnar nerve groove when flexing the elbow, this repeated slippage makes the ulnar nerve by friction and collision and injury. 3.External humeral epicondyle fracture If the fracture block is displaced downward, it can compress the ulnar nerve. 4, traumatic ossification elbow joint is the most prone to traumatic ossification myositis, such as elbow trauma after this ectopic ossification occurs in the vicinity of the ulnar nerve groove, is also a cause of compression of the ulnar nerve. Pathophysiology The ulnar nerve travels medial to the superficial surface of the biceps fascia in the lower part of the upper arm, and descends through the ulnar nerve groove between the medial humeral condyle and the medial wounded condyle to the ulnar carpal flexor and deep finger flexor muscles on the ulnar side of the forearm. The superficial surface of the ulnar nerve groove has the top formed by the communication of the ulnar collateral ligament ulnar flexor carpi radialis fascia and arch ligament, and the channel between them is called the elbow canal, in which the ulnar nerve is restrained, and when the elbow joint is flexed and extended, the ulnar nerve is repeatedly stretched or relaxed in the elbow canal. Diagnostic examination Diagnosis according to clinical manifestations combined with electrophysiological examination. 1, cervical spondylosis nerve root type Cervical spondylosis of the lower cervical segment can occur due to intervertebral foraminal stenosis and cervical nerve irritation symptoms, with numbness and weakness on the ulnar side of the hand as the main manifestation, which has similarity with elbow canal syndrome, the main difference is that there is no abnormal finding in the elbow canal area during cervical spondylosis. 2.Nerve sheath tumor The ulnar nerve sheath tumor of elbow has the same manifestation as elbow canal syndrome, and the segmental thickened ulnar nerve can be found during examination, and Tinel’s sign is positive, but there is no osteoarthritic lesion of elbow. Treatment options For initial and mild symptoms, neurotrophic drugs (e.g., vitamin B1), intra-elbow tube injection of hydrocortisone acetate or confirmatory suxamethasone can be used first. Immobilization with a splint and avoiding elbow flexion can improve symptoms. In severe cases, ulnar nerve anterior surgery is the basic treatment. If the segment of the ulnar nerve is found to be stiff during surgery, the outer membrane of the nerve should be removed and interfascicular release should be performed to completely solve the problem. Normal sensation can be restored more quickly after surgery, but it is more difficult to restore the normal volume of the small muscles of the hand that have atrophied. Disease prevention Avoid traumatic factors.