March 17, 2022
5 min read
sources: Henn CM, et al. J Hand Surg Am. 2016;doi:10.1016/j.jhsa.2016.01.014.
Disclosures: Akelman, Li and Scholten report no relevant financial disclosures.
A 23-year-old woman presented to clinic for evaluation of neck pain, right hand and ulnar forearm numbness and tingling. She reported several years of neck pain and right upper extremity “heaviness.”
During the past few months, she had developed numbness to all her fingers that would come and go. This was the worst in her small and ring fingers. She denied headaches or color changes in her hand.
Examination revealed diminished sensation to her small finger, with a positive Tinel sign at the cubital tunnel, and palpable anterior displacement of the ulnar nerve with elbow flexion. Further examination revealed tenderness in the supraclavicular fossa, a positive elevated arm stress test and negative Adson test. Imaging of the cervical spine and right shoulder revealed rudimentary cervical ribs bilaterally with no Pancoast tumor or other abnormalities (Figure 1).
The patient was diagnosed with neurogenic thoracic outlet syndrome (TOS) with concomitant ulnar neuritis which was due to ulnar nerve instability at the elbow.
What is the best next step in the management of this patient?
See answer below.
Surgical muscle release, nerve and nerve root decompression
The patient was initially managed conservatively with physical therapy for 3 months; however, her right arm became progressively more painful, and she subsequently elected to undergo surgical treatment.
A transverse incision was performed above the right clavicle, the platysma muscle divided in line with the skin incision, and the lateral portion of the sternocleidomastoid muscle partially released. The cervical rib was visibly protruding anteriorly. The omohyoid muscle was exposed and retracted. The external jugular vein was ligated and the fascia over the brachial plexus was released. The cervical rib was notably pushing anteriorly and laterally, tenting the subclavian artery and brachial plexus. The upper brachial plexus and its branches, including the suprascapular nerve, were mobilized from the fascia and retracted. The phrenic nerve was identified over the anterior surface of the anterior scalene muscle and protected. The anterior scalene muscle was released near the rib insertion. The middle and lower trunk nerves were identified and freed from fibrous tissue bands. The subclavian artery was exposed, freed from the cervical rib and retracted. The prominent portion of the cervical rib was removed with a Kerrison rongeur. The long thoracic nerve was exposed and protected, and the middle scalene muscle was released after cervical rib removal. The C8 and T1 nerve roots appeared decompressed after removal of the cervical rib.
Attention was then turned to the elbow. A medial elbow incision was made, the medial antebrachial cutaneous nerve was protected and the fascia over the ulnar nerve released. The ulnar nerve dislocated anterior to the medial epicondyle with elbow flexion and reduced into the ulnar nerve groove with elbow extension. The nerve was decompressed distally by releasing Osborne’s ligament and the fascia of the flexor carpi ulnaris. Dissection was continued proximally and the arcade of Struthers was released. The nerve was noted to be anterior to the intermuscular septum. Therefore, release of the septum from the medial epicondyle was not required. The flexor and pronator muscle tendons were lengthened at the insertion of the medial epicondyle to raise two flaps in a zig-zag fashion and used to make a sling to stabilize the ulnar nerve and prevent displacement. Passive elbow range of motion was performed showing a stable ulnar nerve.
Postoperative chest radiographs were obtained and ruled out pneumothorax after cervical rib resection (Figure 2). The patient was prescribed nerve gliding exercises and physical therapy. She was evaluated at 6 weeks postoperatively and had complete resolution of her symptoms.
Our case is distinctive in that the patient had concomitant neurogenic TOS and ulnar nerve instability. A double-crush mechanism, where compression of a nerve at one level makes it more susceptible to damage at another level, likely contributed to the patient’s symptoms. Clinical studies have supported this mechanism, with associations between compression at the cervical spine, thoracic outlet and distal sites — including the cubital and carpal tunnels — likely due to compromised axoplasmic flow.
Neurogenic TOS is a rare disorder with an estimated prevalence of 1% to 2%. Approximately 90% of TOS are neurogenic and the remaining 10% are arterial or venous. Patients may present with radiating pain or numbness in the neck and upper extremity, which may be exacerbated by position or repetitive use. Patients with “true” neurogenic TOS often present with thenar and hypothenar atrophy (Gilliatt-Sumner hand) and sensory deficiency over the medial forearm and ulnar hand. However, the most common type of neurogenic TOS is the “disputable” type.
Patients often complain of neck and shoulder pain, headaches, ulnar hand numbness radiating to the ulnar forearm, heavy arm feelings, difficulties with performing arm elevation activities, such as brushing teeth and brushing hair, due to increased pain, paresthesias and fatigue. Diagnosis requires a high index of suspicion as there is no definitive electrodiagnostic test. Due to this, patients with neurogenic TOS see multiple doctors before a diagnosis is established. This condition may be associated with cervical ribs, and symptoms may occur after injury or surgery to the head, neck or upper extremity.
Patients will often have localized tenderness or paresthesias with palpation to the scalene triangle or subcoracoid space and may have a positive upper limb tension test or elevated arm stress test. The elevated arm stress test, known as a Roos test, is performed by having the patient raise both arms in the 90° abduction-external rotation position with shoulders and elbows in the frontal plane of the chest. The patient opens and closes their hands slowly during a 3-minute period. Reproduction of the patient’s usual symptoms along the entire extremity is considered a positive test.
Suspected neurogenic TOS workup
For patients with suspected neurogenic TOS, workup includes radiographs of the cervical spine or chest to evaluate for cervical ribs and Pancoast tumor. If radiographs are negative or equivocal, EMG, nerve conduction studies and angiography may be indicated to rule out distal compressive neuropathies, cervical radiculopathy or vascular disease. Auscultation or ultrasound of the subclavian vessels may be performed, with a bruit providing a positive prognostic sign for the success of surgical decompression. First-line treatment includes physical therapy with postural and activity modification, as well as medications including gabapentin and pregabalin. When conservative management fails, operative management includes excision or release of anomalous anatomy, resection of the first rib if it is compressing the plexus, division of the anterior and middle scalene muscles, neurolysis of the involved brachial plexus and release of the pectoralis minor tendon as needed.
Cubital tunnel syndrome is a more common entity, with reported incidence ranging from 1.9% to 5.9%. Surgical management of cubital tunnel syndrome remains controversial, and options include in situ decompression, medial epicondylectomy, subcutaneous anterior transposition, intramuscular transposition and submuscular transposition. Prior meta-analyses have shown decreased complications with in situ decompression vs. transposition; however, transposition of unstable ulnar nerves may lead to improved outcomes compared with in situ decompression.
The important takeaway points for this case include having a high index of suspicion for double-crush neuropathies and understanding diagnostic criteria, workup and operative techniques for neurogenic thoracic outlet and cubital tunnel syndromes.
- Jones MR, et al. Pain Ther. 2019;doi:10.1007/s40122-019-0124-2.
- Kuhn JE, et al. J Am Acad Orthop Surg. 2015;doi:10.5435/JAAOS-D-13-00215.
- Novak CB, et al. J Hand Surg Am. 1993;doi:10.1016/0363-5023(93)90364-9.
- Staples JR, et al. J Am Acad Orthop Surg. 2017;doi:10.5435/JAAOS-D-15-00261.
- For more information:
- Matthew R Akelman, MD; Zhongyu J Li, MD, PhD; other Donald Jay Scholten II, MD, PhD, can be reached at Department of Orthopedics, Wake Forest School of Medicine, Atrium Health Wake Forest Baptist, 1 Medical Center Blvd., Winston-Salem, NC 27157. Akelman’s email: email@example.com. Li’s email: firstname.lastname@example.org. Scholten’s email: email@example.com.
- Edited by Steven D. Jones Jr., MD, other Donald (DJ) Scholten, MD, PhD. Jones is a chief resident in the department of orthopedic surgery at the University of Colorado. He will pursue a fellowship in sports medicine at Stanford University following residency completion. Scholten is a chief resident in the department of orthopedic surgery at Wake Forest University School of Medicine in Winston-Salem, North Carolina. He will be a sports medicine fellow at the University of Michigan following residency. For information on submitting Orthopedics Today Grand Rounds cases, please email: firstname.lastname@example.org.