Instrument set for endoscopically assisted decompression of the ulnar nerve Arthroscopy
Instrument set for endoscopically assisted decompression of the ulnar nerve Introduction The compression of the ulnar nerve in the sulcus of the ulnar nerve posterior to the medial epicondyle of the humerus is the second most common nerve compression after carpal tunnel syndrome. Therapeutically, various treatments have been available up to now such as nerve decompression without transposition (in situ decompression), with subcutaneous transposition of the nerve in a ventral direction (ventral transposition) or transposition of the nerve in a ventral direction in the muscle (submuscular transposition). The success rates of these operations were approximately 80-90 %. Generally, however, these interventions involved large incisions. Thanks to the work of R. Hoffmann and M. Siemionow, there is now a new promising technique, endoscopically assisted decompression of the ulnar nerve. The advantage of this endoscopically assisted technique is that a much smaller incision can be used while at the same time extending the length of the neurolysis. Anatomy The ulnar nerve runs from the upper arm posterior to the medial epicondyle of the humerus in the sulcus of the ulnar nerve (cubital tunnel) to enter the lower arm between the two heads of the flexor carpi ulnaris muscle. Anatomical constrictions in the course of the nerve are defined. Proximal to the humerus there is fibrous band structure (arcade of Struthers). In the course of the retrocondylar groove, the nerve is below Osborne's ligament that runs from the medial epicondyle to the olecranon. Credit is due to Hoffmann and Siemionow for the anatomical dissection of the proximal lower arm. Here, there are three defined constrictions between the two bellies of the flexor carpi ulnaris muscle located 3-4.5 cm, 5-5.5 cm and 7-9 cm from the centre of the retrocondylar groove. With the aid of endoscopically assisted decompression, it is possible to release both the proximal and distal constrictions of the nerve without needing to open the skin over the same distance. This leads to less morbidity, fast improvement of the symptoms and fast rehabilitation compared with classic techniques. 2
Arthroscopy Operating technique The correct positioning of the patient is important for a successful operation. To simplify access for the surgeon, the table and hand table should be as high as possible. This allows a better view of the operative site. As with all other interventions on the upper extremity, the operation is performed under plexus anaesthesia, where necessary under general anaesthesia with a tourniquet applied. The operation begins by marking the incision posterior to the medial epicondyle. Following incision and subcutaneous dissection, the ulnar nerve is exposed posterior to the medial epicondyle. The ulnar nerve is exposed in the sulcus in both the proximal and distal direction. 3
Instrument set for endoscopically assisted decompression of the ulnar nerve The skin is then undermined subcutaneously in the proximal direction with a dressing forceps to create a tunnel for the dissection to follow. The proximal dissection is then performed with the aid of the illuminated speculum. 4
Arthroscopy Using the optical dissector, the ulnar nerve is dissected over a length of approximately 7-10 cm. The operation continues in the next step in a distal direction. The skin is once again undermined with a dressing forceps as the first step in the distal dissection. 5
Instrument set for endoscopically assisted decompression of the ulnar nerve Finally, the speculum is inserted under vision and the nerve is dissected. At this point, particular care must be taken with motor branches. Following this, the optical dissector is introduced subcutaneously and the muscle fascia of the flexor carpi ulnaris muscle is divided. When dividing the muscle fascia, care must be taken with skin nerves running subcutaneously above the fascia. Subcutaneous veins can also cause problems in this area. After dividing the fascia in the distal direction, the nerve is dissected under endoscopic vision. 6
Arthroscopy The operation is completed by inserting a Redon drain and elastocompressive bandaging of the arm. Follow-up The Redon drain is removed on the first postoperative day. The patient wears an elastic bandage for a further four weeks. This prevents maximum flexion and the associated ventral luxation of the nerve. 7
Instrument set and accessories created with the cooperation of Prof. Dr. Peter Hahn, Vulpiusklinik, Bad Rappenau, Germany spirit of excellence Article Name Types Optical dissector 891607001 Speculum with light attachment 891607002 Printed on paper based on cellulose which has been bleached without the use of chlorine. Duplay dressing forceps 823300300 Metzenbaum scissors, 230 mm 822403300 Metzenbaum scissors, modular, 230 mm 8390.0083 Telescope 8880.543 Specifications subject to change without notice. Light cable 8061.353 RICHARD WOLF GmbH 75434 Knittlingen PF 1164 Telephone +49 70 43 35-0 Telefax +49 70 43 35-300 GERMANY info@richard-wolf.com www.richard-wolf.com B 766.II.09.GB www.stuetzlepartner.de AUSTRIA BELGIUM / NETHERLANDS FRANCE GERMANY INDIA U.A.E. UK USA