Faculty Bibliography

Compressive neuropathy of the ulnar nerve in the upper limb is a common problem that frequently results in severe disabilities. At the elbow, Lundborg concluded that the nerve was 'asking for trouble' because of its anatomic course through confined spaces and posterior to the axis of elbow flexion. Normally, the ulnar nerve is subjected to stretch and compression forces that are moderated by its ability to glide in its anatomic path around the elbow. When normal excursion is restricted, irritation ensues. This results in a cycle of perineural scarring, further loss of excursion, and progressive nerve damage. Initial treatment for the acute and subacute neuropathy at the elbow is nonsurgical. Rest and avoiding pressure on the nerve may suffice, but if symptoms persist, splint immobilization of the elbow and wrist is warranted. For chronic neuropathy associated with muscle weakness, or neuropathy that does not respond to conservative measures, surgery is usually necessary. A variety of surgical procedures have been described in the medical literature, and deciding on the most effective procedure can be difficult considering the excellent results claimed by proponents for each. Unfortunately, there is a paucity of information based on prospective randomized clinical studies comparing the different surgical methods. Dellon attempted to provide some guidelines by reviewing the data in 50 articles dealing with nonsurgical and surgical treatment of ulnar neuropathies at the elbow. In order to provide uniform data, he re-interpreted the data in these articles using his own system for staging nerve compression. He reported that treatment was most successful for mild neuropathies, a conclusion few would challenge. Excellent results were also achieved in 50% of patients with mild neuropathies that were treated nonsurgically and in more than 90% treated by surgery, regardless of the procedure. For moderate neuropathies, nonsurgical treatment was generally unsuccessful, as were decompressions in situ. Medial epicondylectomies were effective in only 50% of cases and they had the highest recurrence rate. Regarding ulnar nerve transpositions, each method has its proponents, usually based on the training and experience of the surgeon. Subcutaneous transposition is the least complicated. It is an effective procedure, particularly in the elderly and in patients who have a thick layer of adipose tissue in their arms. It is the procedure of choice for repositioning the nerve during surgical reductions of acute fractures, arthroplasties of the elbow, and secondary neurorrhaphies. Intramuscular and submuscular transpositions are more complicated procedures. Although proponents of intramuscular transposition report favorable results, the procedure can result in severe postoperative perineural scarring. Submuscular transposition has a high degree of success and is generally accepted to be the preferred procedure when prior surgery has been unsuccessful. I also prefer it as the primary procedure for most chronic neuropathies that require surgery. Compressive neuropathies of the ulnar nerve in the canal of Guyon are less common, but they can also result in significant disabilities. Compression can occur in 1 of 3 zones. Zone 1 is in the most proximal portion of the canal, where the nerve is a single structure consisting of motor and sensory fascicles, and zones 2 and 3 are distal where the ulnar nerve has divided into motor and sensory branches. The clinical picture correlates with the zone in which compression occurs

Ulnar nerve compression at the elbow can occur at any of five sites that begin proximally at the arcade of Struthers and end distally where the nerve exits the flexor carpi ulnaris muscle in the forearm. Compression occurs most commonly at two sites-the epicondylar groove and the point where the nerve passes between the two heads of the flexor carpi ulnaris muscle (i.e., the true cubital tunnel). The differential diagnosis of ulnar neuropathies at the elbow includes lesions that cause additional proximal or distal nerve compression and systemic metabolic disorders. A complete history and a thorough physical examination are essential first steps in establishing a correct diagnosis. Electrodiagnostic studies may be useful, especially when the site of compression cannot be determined by physical examination, when compression may be at multiple levels, and when there are systemic and metabolic problems

Initial treatment of most compressive neuropathies at the elbow is nonoperative, consisting of rest, avoidance of elbow flexion, and, when necessary, temporary immobilization of the elbow and wrist. If symptoms persist, particularly when accompanied by muscle weakness, surgery is usually indicated. Operative procedures include decompression without transposition of the nerve (in situ or by means of medial epicondylectomy) and decompression with transposition of the nerve carried out in a subcutaneous, intramuscular, or submuscular fashion. The indications, advantages, disadvantages, and surgical technique of each operative procedure are discussed

In the past several years, the role of MR imaging in diagnosing pathologic conditions of the elbow has dramatically increased. Aside from imaging soft-tissue tumors, it can accurately visualize partial and complete tears of tendons and ligaments, as well as displacement of epiphyseal fractures in children. Its role in identifying loose bodies, particularly when they are nonosseous, and areas of osteochondritis dissecans has also increased. The use of MR imaging for diagnosing neuropathies, particularly when electrodiagnostic studies are negative, offers exciting possibilities as additional technical improvements are developed

We performed an in vitro study using canine flexor tendons to compare the tensile properties of a suture technique for flexor tendon repair with the standard modified Kessler technique. The technique employs a central wire loop that connects the two transverse limbs of the modified Kessler suture. Both techniques were studied with and without a Lembert epitendinous stitch. The technique combined with an epitendinous suture provided the strongest resistance to gap formation, and its load at gap initiation was 100% greater than the load in tendons repaired with the modified Kessler and an epitendinous suture. Because of its increased resistance to gap formation, this suture technique may provide a safer margin for controlled early active motion after flexor tendon repair.

An arteriovenous (AV) shunt as a method of restoring venous drainage during replantation was examined by use of the rabbit ear model. The results were compared to ears replanted using one vein (1:1) or two veins (2:1) for venous drainage. The success rate for AV shunt replantations was found similar to that of replantations with a 1:1 ratio, but lower than that of ears with a 2:1 ratio. Postoperatively, ears replanted using an AV shunt or a 1:1 ratio revealed more swelling and lower tissue oxygenation than ears with a 2:1 ratio. After 10-14 days, all ears that survived were similar in appearance, regardless of method of replantation. Microscopic venules crossing the replanted interface appeared at seven days following surgery in all groups. The authors conclude that the AV shunt method offers an alternative to venous anastomosis when vein-to-vein reconstruction cannot be established.

Tomography and magnetic resonance imaging (MRI) are important imaging techniques in the diagnosis and management of a wide variety of wrist disorders. They have been useful for evaluating fractures, tumors, arthritic conditions and avascular necrosis involving the carpal bones as well as injuries affecting the radiocarpal and intercarpal ligaments and the triangular fibrocartilage complex. The indications and clinical applications of each imaging technique will be discussed.

Tomography, which permits a far more accurate visualization of lesions than conventional radiographs, is conducted via several different methods, depending on the specific movement of the x-ray tube. Linear tomography is the simplest method but produces images that appear streaked. Zonotomography, which uses an elliptical or figure-8 movement of the x-ray tube, creates a uniform blurring of structures and a much clearer resolution of the plane of focus. Even sharper images are produced by multidirectional trispiral tomography, which is described as well as its application to specific anatomic areas of the wrist. The normal anatomy and a variety of problems of the wrist as visualized with magnetic resonance imaging are also described.

A new 'bloodless' technique (Ilizarov) was used to correct 36 limb deformities in 29 children. There were six leg length discrepancies, five achondroplasias, four deformed feet, five joint contractures, one rotational deformity of tibia, and in three the apparatus was used as an external fixator after corrective osteotomy. Lengthening was accomplished in 15 of the 16 procedures (93%). Average increase in femur length was 10 cm (32%), in tibial length 7.5 cm (30%), in humerus 11 cm (40%). Bony union was achieved in two out of five pseudoarthroses. Four deformed feet were fully corrected. Joint contractures were corrected in four out of five. The complication rate is as high as in other methods but with the Ilizarov apparatus, longer segments of bone were lengthened and more complex deformities were treated. Complications lessened as experience was gained