Definition of ulnar nerve entrapment at the elbow:
Ulnar nerve entrapment at the elbow (cubital tunnel syndrome) is a relatively frequent tunnel syndrome. It is a compression of the ulnar nerve at the elbow by two main anatomical structures: Osborne’s ligament and the aponeurotic arcade of the flexor carpi ulnaris (FCU) muscle. Compression of the ulnar nerve at the elbow manifests itself by tingling at the hand’s two last fingers as well as weakness in the hand.
Video of endoscopic treatment of ulnar nerve entrapment (CTS) at the elbow:
Diagnosis of cubital tunnel syndrome:
Several functional signs can occur, simultaneously or separately: tingling (paresthesias) in the ring finger and the little finger, pain at the inner aspect of the elbow and the hand, diminished strength and hand fatigability. In the presence of a carpal tunnel syndrome, the clinical examination must focus on measuring epicritic sensibility (Weber test) and global grip strength (Jamar), which will make it possible to evaluate the severity of the CTS.
Ulnar nerve entrapment at the elbow has various levels of severity:
Early ulnar nerve entrapment: tingling (paresthesia) is felt in the middle or at the end of the night, grip strength is not diminished. At this stage, simple injections or even a nocturnal splint will be enough to reduce the discomfort caused by ulnar nerve entrapment.
Intermediate ulnar nerve entrapment: discomfort is felt during the day. Forceful activities will be affected first, and then gradually daily activities. At this stage medical treatment can be discussed but only surgery can permanently relieve ulnar nerve entrapement.
Ulnar nerve entrapment with deficit: hand sensibility is diminished and muscle wasting affects some muscles of the thumb, hand paralysis and deformity can occur: this is called the ulnar claw. All activities are disrupted, the loss of sensation and strength is severe. At this stage surgery is the only option, and operating on the ulnar nerve at the elbow is unavoidable.
Endoscopic surgery of ulnar nerve entrapment at the elbow:
When no instability of the ulnar nerve or osteoarticular morphological anomaly of the elbow is found, that is in most cases, endoscopic ulnar nerve release (decompression) can be considered.
This wrist surgery is a specialist procedure. It derives from the endoscopic carpal tunnel surgery.
For this endoscopic surgery an 8-mm incision is made at the elbow’s epicondyle-olecranon groove, careful dissection is carried to the Osborne’s ligament, the ulnar nerve is located and a blunt guide is introduced in the tunnel.
The endoscope is first inserted proximally, the absence of interposition is verified step by step, the upper part of the epicondyle-olecranon ligament is dissected as well as any coexisting Struthers arcade. Once the ulnar nerve at the elbow is released proximally, direct endoscopic verification of the ulnar nerve is performed to confirm completeness of decompression.
Once proximal endoscopic neurolysis (decompression) is complete, the blunt guide is introduced distally, and then the endoscope, so that the dissection of the lower extremity of the epicondyle-olecranon ligament and of the arcade of the FCU muscle is performed under constant endoscopic monitoring.
At the end of the procedure, all compression sites have been released and with the endoscope, it is possible to confirm that the ulnar nerve has been completely decompressed.
The wounds are closed with Steri-strip. In this endoscopic surgery of ulnar nerve entrapment at the elbow, no suture is necessary.
Recovery after endoscopic surgery on the ulnar nerve at the elbow:
After surgery there is no elbow or wrist immobilization, all daily life activities as well as self-care can resume after one week. In normal recovery, elbow pain occurs in daily activities for one month, and sometimes longer in forceful and resistive movements, until the third month after surgery. Rugby can thus resume after 2 to 3 months. When pre-operative axonal degeneration or sensory or motor deficit is found, complete resolution of paresthesias (tingling) and recovery of the hand’s strength may require the axons of the ulnar nerve to grow back to the fingertips, which can take more than six months. Driving often resumes at the end of the 3rd post-operative week.