Cheiralgia Paresthetica/Wartenberg's Syndrome

                                  Dr. KS Dhillon

Introduction

The radial nerve is susceptible to compression at several sites throughout its course. Compression of the superficial branch of the radial nerve in the forearm is called cheiralgia paresthetica. In 1932 Wartenberg reported 5 cases of mononeuropathy of the superficial branch of the radial nerve [1]. The report was in German. Wartenberg gave it the name “cheiralgia paresthetica” which means hand pain [2,3]. Ehrilich et al. translated Wartenberg’s paper into English in a condensed form in a 1986 report in the Journal of Hand Surgery [4]. It is also commonly known as Wartenburg syndrome and superficial radial nerve palsy.

The superficial radial nerve is purely sensory and it does not have any motor component. The condition presents with pain and burning located on the dorsal and radial side of the hand. It is aggravated by activities such as pronation, pinching, and gripping.

The radial nerve comes from the posterior cord of the brachial plexus and has fibers from the C5, C6, C7, C8, and sometimes T1 nerve roots. It comes down between the long head of the triceps and axillary artery and enters the posterior compartment of the arm via the triangular interval. It continues along the medial proximal upper arm between the long and medial head of the triceps until it reaches the spiral groove. It passes distally and laterally around the posterior humerus, where it penetrates the lateral intermuscular septum and gains access to the anterior compartment of the arm. It enters the anterior compartment distal to the deltoid insertion at approximately 11 cm proximal to the elbow. The nerve continues anteriorly to the lateral epicondyle between the brachialis and brachioradialis at the elbow to enter the forearm.

About 3 to 5 cm proximal to the supinator, the radial nerve divides into the posterior interosseous nerve and the superficial branch of the radial nerve. The posterior interosseous nerve continues deep to the supinator. The superficial branch of the radial nerve continues superficially to the supinator and deep to the ulnar margin of the brachioradialis in the anterolateral aspect of the forearm. Here it briefly runs alongside the radial artery. At about 9 cm proximal to the radial styloid process, it then pierces the deep fascia between the middle and distal third of the forearm, to emerge between the brachioradialis and extensor carpi radialis longus. Here it becomes subcutaneous. The superficial branch then ramifies again at approximately 4.9 cm proximal to the styloid process into dorsomedial and dorsolateral branches. These branches travel alongside the cephalic vein and proceed across the first dorsal compartment of the wrist and the abductor pollicis longus and the extensor pollicis brevis. The dorsolateral branch supplies the dorsolateral aspect of the thumb proximal to the interphalangeal joint. The dorsomedial branch supplies the dorsomedial thumb proximal to the interphalangeal joint, dorsoradial half of the hand and dorsal aspect of the index, middle finger, and radial half of ring fingers proximal to the distal interphalangeal joint [5-9].

Etiology

The radial nerve can be compressed at several locations along its length. The superficial location of the terminal branches makes them susceptible to local trauma [10]. Tight handcuffs and tight wrist watches can compress the nerve over the lateral wrist [5,6,11]. Its superficial location also predisposes it to injury from penetrating wounds [8]. It is also at risk for compression caused by distal radius fracture fragments and by soft tissue masses like lipomas or ganglion cysts [11,12]. The nerve is susceptible to iatrogenic injury during internal or percutaneous fixation of distal radius fractures, first dorsal compartment release, wrist arthroscopy, and external fixation placement. Procedures such as acupuncture, cephalic venipuncture and cannulation, and radial arterial line removal can be complicated by thrombosis [8,13] and have been known to cause nerve palsies. Steroid injections into the tendon sheath for de Quervain's tenosynovitis can damage the nerve and can cause subdermal atrophy predisposing the nerve to injury [8,10].

The nerve is vulnerable where it passes from deep to superficial [6]. Compression can occur from fascial bands between the brachioradialis and extensor carpi radialis longus and fascial rings of the dorsal brachioradialis. Repetitive pronation and supination and hyperpronation can trap the nerve between the brachioradialis and extensor carpi radialis longus [11]. When the arm moves into pronation, the extensor carpi radialis longus crosses beneath the brachioradialis and can compress the nerve.

Epidemiology

Cheiralgia paresthetica is a relatively rare condition. Carpal tunnel syndrome has an annual incidence rate between 0.1 and 0.35%; ulnar nerve compression syndromes have a rate of 0.02% and radial nerve compression syndromes have a rate of 0.003% [6]. Cheiralgia paresthetic makes up only one subset of radial nerve compression syndromes. The annual incidence rate of cheiralgia paresthetica is unknown. It affects women more often than men at a ratio of 4 to 1 and it is seen most commonly from ages 20 to 70 [14]. 

Pathophysiology

Cheiralgia paresthetica results from compression of the superficial branch of the radial nerve. The degree of injury and symptoms are related to the amount of force on the nerve and the duration of compression of the nerve [9]. Compression can cause injury to the myelin sheath of the nerve, microvasculature of the nerve, or the nerve itself. Mild compression produces obstruction of venous flow which produces congestion, and edema. This can produce ischemia that leads to Schwann cell necrosis and demyelination. With severe compression, ischemia results from obstruction of arterial flow. This can lead to axonal injury and death from the resultant ischemia. The duration of compression also has different effects on the nerve. Intermittent compression can lead to transient decreases in blood flow. Chronic compression results in longstanding decreases in blood flow. These chronic changes can lead to demyelination, inflammation, fibrosis, scar formation, and eventual axonal degeneration [5,7]. It is important to remove the offending agent before severe nerve damage occurs. There is a better chance of recovery with early removal of the offending agent. Remyelination of the nerve can take a few weeks. Axonal regrowth is very slow at a rate of 1mm a day [5].

History 

The patient usually presents with pain, tingling, and paresthesias over the dorsolateral aspect of the hand, wrist, and fingers [8,15]. The symptoms can extend from the dorsal radial forearm into the thumb, index, and middle fingers [6]. Most of the time patients are unable to localize the pain to a specific area. The pain is often described as burning or shooting in nature. The sensation of numbness and tingling may be present, although this is much rarer.

The symptoms can be acute, intermittent, or chronic. This is related to the cause of nerve irritation. Other symptoms can include allodynia, dysesthesias, and hypoesthesias. Flexion and ulnar deviation of the wrist can exacerbate the symptoms. 

Physical Examination 

Physical examination for Cheiralgia paresthetica should focus on determining the affected area of sensory abnormality on the dorsolateral aspect of the hand. One study reported a 100% altered vibration and fine touch sensation on the dorsolateral aspect of the hand [16]. Patients may also present with weakened pinch and grip strength due to pain. Symptoms are reproduced with forced pronation, ulnar deviation, flexion of the wrist, and resisted isometrics of the wrist extensors and brachioradialis [17,18].

A common finding of Cheiralgia paresthetica is a positive Tinel’s sign over the course of the superficial branch of the radial nerve, commonly over the radial styloid or just distal to the brachioradialis muscle belly, where the nerve exits from the deep fascia [6,18,19].

Since Cheiralgia paresthetica is highly comorbid with DeQuervain’s tenosynovitis, patients may very likely present with a positive Finkelstein test [3,18,20]. However, the distinguishing feature of cheiralgia paresthetica from De Quervain’s tenosynovitis is that the pain is present regardless of position when performing a Finkelstein test [21].

Nerve conduction studies can also be used to diagnose cheiralgia paresthetica; however, this has shown limited effectiveness [3,18]. When considering other comorbid pathologies, nerve blocks with lidocaine may be used to rule out associated lateral antebrachial cutaneous nerve injury [8].

Evaluation

Multiple diagnostic modalities can be used to evaluate cheiralgia paresthetica. These include [8,22]:

• Electromyography/Nerve Conduction Study- Able to identify slowing of nerve conduction velocities as compared to accepted normal values. Usually there is no slowing present. May be able to identify the location and nature of nerve injury.

• Ultrasound- It can help distinguish between the different causes of wrist pain including de Quervain tenosynovitis, cheiralgia paresthetica, and thumb carpometacarpal joint arthritis. It is also able to identify areas of nerve entrapment or compression.

• Plain Radiographs- It is able to identify any bony prominences or orthopedic hardware present.

• Magnetic Resonance Imaging- T1-weighted images can identify the nerve anatomy including any narrowing or enlargement that may be caused by its entrapment. Water-sensitive sequences including fat-suppressed T2-weighted, fat-suppressed proton density-weighted, and short tau inversion recovery (STIR) images can identify changes in the nerve itself including edema and enhancement.

Differential Diagnosis

The differential diagnosis includes the following:

• De Quervain's Tenosynovitis [8,22]- Stenosing tenosynovitis in the first dorsal extensor compartment. Pain, tenderness, and swelling over the lateral wrist. No sensory disturbance. Cheiralgia paresthetica gives a false positive Finkelstein test. Up to 50% of patients with cheiralgia paresthetica also get a diagnosis of de Quervain tenosynovitis

• Lateral Antebrachial Cutaneous Nerve Neuritis- The lateral antebrachial cutaneous nerve provides sensation to the lateral forearm. A positive Tinel test over the lateral antebrachial cutaneous nerve may be mistaken for a positive Tinel test over the superficial branch of the radial nerve. The superficial branch of the radial nerve and lateral antebrachial cutaneous nerve neuritis may coexist. A sensory overlap between the superficial branch of the radial nerve and lateral antebrachial cutaneous nerve in the dorsoradial hand occurs in 21% to 75% of patients. Tinel's test is done just distal to the antecubital fossa just medial to the brachioradialis where the lateral antebrachial cutaneous nerve exits deep fascia.  

• Thumb Carpometacarpal Joint Arthritis- Pain at the radial aspect of the wrist. Pain and weakness with motion, grip, and pinch. Crepitus with motion of the thumb. The Grind Test is positive. There is pain with a circular motion of the thumb while applying axial compression. An adduction deformity of the thumb carpometacarpal joint may be present alone or in combination with a hyperextension deformity of the thumb metacarpophalangeal joint (Z-type deformity). There is no sensory deficit. 

• Proximal Nerve Lesion- Spinal cords lesions, nerve root compressions, brachial plexus injuries encompassing the posterior cords, radial nerve palsies, posterior interosseous nerve syndrome, and radial tunnel syndrome can be present. There will be sensory disturbances associated with strength deficits.

• Intersection Syndrome- There is pain in the dorsoradial aspect of the forearm. Crepitus over the intersection of abductor pollicis longus and extensor pollicis brevis with extensor carpi radialis longus and extensor carpi radialis brevis may be present. There is no sensory deficit.

Treatment 

The treatment of cheiralgia paresthetica is mainly conservative. Attention is first focused on removing sources of external compression that could be causing the neuropathy. The patient is encouraged to rest, avoid any provocative maneuvers, and alter work activities that may exacerbate the symptoms. Also, NSAIDs and nerve medications can be used to augment therapy [6]. In refractory individuals, temporary thumb spica splinting and ultrasound-guided corticosteroid injections can be carried out [23]. Underlying medical problems such as diabetes that can compound the symptoms require assessment and treatment. Up to 71% of patients treated nonoperatively have good to excellent outcomes [6].

However, another prospective study showed less effectiveness following 6 months of wrist and forearm splinting, restriction of activities, physiotherapy, and anti-inflammatory medications with only 30% of the patients showing improvement [24].

Surgery is done when there is failure of nonoperative treatment. Conservative treatment should be attempted for 6 months before any surgical intervention. Clinicians have to be cautious when treating patients with painless paresthesias as surgical complications may create painful neurologic symptoms [6]. 

There are several surgical techniques described for the treatment of cheiralgia paresthetica. These include neurolysis, endoscopically assisted neurolysis [25], neurolysis, and nerve wrapping with material such as amniotic membranes and temporoparietal fascial flaps [15], and microsurgical intraneural neurolysis. Other techniques focus on removing the causes of compression and these include the removal of lipomas, fascial bands, bony spikes, etc., and even longitudinal plication of the brachioradialis tendon [26].

Surgical decompression

To approach the superficial branch of the radial nerve, a line is drawn from the radial styloid process to the border of the brachioradialis 10 cm proximally. The area with the most pronounced Tinel response, tenderness, and allodynia is identified. Then the incision is centered over this site. Skin flaps are elevated to identify the brachioradialis and extensor carpi radialis longus tendons. The superficial branch of the radial nerve generally appears between the two tendons with the brachioradialis located above and the extensor carpi radialis longus located below [15]. 

The nerve is carefully dissected out and freed from adhesions. Any masses, adhesions, or fascial bands that could be compressing the nerve are removed. Once the nerve is fully decompressed, one can choose to wrap the nerve in a number of different adhesive barriers, including but not limited to amniotic membranes or fascial flaps. The area of nerve compression is measured, and the adhesion barrier is trimmed to match. It is then placed around the nerve and secured loosely in place with 8-0 nylon sutures. The circumferential coverage is done without strangulation of the nerve. After vascularity is confirmed, and hemostasis is done, one can proceed with layered closure [15].

Postoperatively early range of motion exercises are carried out with all restrictions lifted by 2 weeks after surgery. Patients usually receive 4 to 6 weeks of therapy and they achieve maximum medical improvement at 60 to 90 days after surgery.

Prognosis

The outcomes for the treatment of cheiralgia paresthetica are good. Spontaneous resolution of symptoms is very common. Up to 71% of patients treated nonoperatively have good to excellent outcomes. The outcome of surgical treatment are mixed. Lanzetta and Foucher reported a 74% success rate with surgical intervention; while Calfee et al. report only modest results with 55% of patients treated operatively continued to have symptoms at follow-up of 3.5 years [6]. Gaspar et al. also found that several patients treated with simple nerve decompression do not have reliable results. Neurolysis for entrapment of the superficial branch of the radial nerve has greater recurrence rates and worse outcomes as compared to other peripheral nerve entrapment syndromes [15].

Complications

Complications include failed decompression, persistent pain and numbness, wound dehiscence, infection, worsening of symptoms, iatrogenic nerve injury, and injury to surrounding structures. 

Conclusion

Cheiralgia paresthetica is an under recognized entity and is often

comorbid with other pathologies of the hand or wrist. Due to overlapping

symptoms and physical examination findings with conditions such as De

Quervain’s tenosynovitis and other neuropathies involving the radial

nerve, it is often misdiagnosed and this leads to undertreatment. A detailed physical examination should be undertaken in order to correctly identify the condition and to avoid inappropriate surgical procedures such as a first extensor compartment release for De Quervain’s tenosynovitis. Once identified, conservative treatment is initiated, which includes immobilization, removal of compressive agents around the wrist, as well as rest from repetitive activities involving pronation and supination of the wrist. If conservative treatment fails, surgical decompression and a full fascial release overlying the superficial radial nerve is carried out.

References

1. Wartenberg R. Cheiralgia paresthetica. Z Ger Neurol Psychiatry 1932; 141: 145-55. [Isolated neuritis of the superficial radial nerve.

2. Sprofkin BE. Cheiralgia paresthetica; Wartenberg’s disease. Neurology 1954; 4(11): 857-62.

3. Lanzetta M, Foucher G. Entrapment of the superficial branch of the radial nerve (Wartenberg’s syndrome). A report of 52 cases. Int Orthop 1993; 17(6): 342-5.

4. Ehrlich W, Dellon AL, Mackinnon S. Cheiralgia paresthetica (entrapment of the radial sensory nerve). J Hand Surg Am 1986; 11A: 196-9.

5. Doughty CT, Bowley MP. Entrapment Neuropathies of the Upper Extremity. Med Clin North Am. 2019 Mar;103(2):357-370.

6. Knutsen EJ, Calfee RP. Uncommon upper extremity compression neuropathies. Hand Clin. 2013 Aug;29(3):443-53.

7. Popinchalk SP, Schaffer AA. Physical examination of upper extremity compressive neuropathies. Orthop Clin North Am. 2012 Oct;43(4):417-30. 

8. Jacobson JA, Fessell DP, Lobo Lda G, Yang LJ. Entrapment neuropathies I: upper limb (carpal tunnel excluded). Semin Musculoskelet Radiol. 2010 Nov;14(5):473-86. 

9. Latef TJ, Bilal M, Vetter M, Iwanaga J, Oskouian RJ, Tubbs RS. Injury of the Radial Nerve in the Arm: A Review. Cureus. 2018 Feb 16; 10(2):e2199.

10. Chodoroff G, Honet JC. Cheiralgia paresthetica and linear atrophy as a complication of local steroid injection. Arch Phys Med Rehabil. 1985 Sep;66(9):637-9.

11. Patel A, Pierce P, Chiu DTW. A fascial band implicated in Wartenberg syndrome. Plast Reconstr Surg. 2014 Mar;133(3): 440e-442e.

12. Tosun N, Tuncay I, Akpinar F. Entrapment of the sensory branch of the radial nerve (Wartenberg's syndrome): an unusual cause. Tohoku J Exp Med. 2001 Mar;193(3):251-4.

13. Khalifeh A, Khashab T, Huffner M, Rezvani ZN, Kwan J, Toursavadkohi S. Radial neuropathy following arterial line removal: A rare complication from a routine ICU procedure. SAGE Open Med Case Rep. 2018;6:2050313X18760740.

14. Dellon AL, Mackinnon SE. Radial sensory nerve entrapment. Arch Neurol. 1986 Aug;43(8):833-5.

15. Gaspar MP, Kane PM, Vosbikian MM, Ketonis C, Rekant MS. Neurolysis with Amniotic Membrane Nerve Wrapping for Treatment of Secondary Wartenberg Syndrome: A Preliminary Report. J Hand Surg Asian Pac Vol. 2017 Jun;22(2):222-228.

16. Robson AJ, See MS, Ellis H (2008) Applied anatomy of the superficial branch of the radial nerve. Clinical Anatomy. 21(1):38–45.

17. Ehrlich W, Dellon AL, Mackinnon SE (1986) Cheiralgia paresthetica (entrapment of the radial sensory nerve). Journal of Hand Surgery.11 (2):196–199.

18. Lee Dellon A, Mackinnon SE (1986) Radial sensory nerve entrapment in the forearm. The Journal of Hand Surgery. 11(2):199–205.

19. Lanzetta M, Foucher G (1993) Entrapment of the superficial branch of the radial nerve (Wartenberg’s syndrome). International orthopaedics. 17(6):342–345.

20. Stahl S, Kaufman T (1997) Cheiralgia paresthetica—entrapment of the superficial branch of the radial nerve: a report of 15 cases. European Journal of Plastic Surgery. 20(2):57–59.

21. Plancher K, Peterson R, Steinchen J (1996) Compressive neuropathies and tendinopathies in the athletic elbow and wrist. Clinical Journal of Sport Medicine. (15):331–369.

22. Tagliafico A, Cadoni A, Fisci E, Gennaro S, Molfetta L, Perez MM, Klauser AS, Martinoli C. Nerves of the hand beyond the carpal tunnel. Semin Musculoskelet Radiol. 2012 Apr;16(2):129-36.

23. Kleinert JM, Mehta S. Radial nerve entrapment. Orthop Clin North Am. 1996 Apr;27(2):305-15.

24. Robson AJ, See MS, Ellis H (2008) Applied anatomy of the superficial branch of the radial nerve. Clinical Anatomy. 21(1):38–45.

25. Spies CK, Müller LP, Oppermann J, Neiss WF, Hahn P, Unglaub F. [Surgical decompression of the superficial radial nerve: Wartenberg syndrome]. Oper Orthop Traumatol. 2016 Apr;28(2):145-52.

26. Zöch G, Aigner N. [Wartenberg syndrome: a rare or rarely diagnosed compression syndrome of the radial nerve?]. Handchir Mikrochir Plast Chir. 1997 May;29(3):139-43.