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Split Brachioradialis Tendon Causing Wartenberg Syndrome in a Professional Baseball Pitcher

Open AccessPublished:January 18, 2023DOI:https://doi.org/10.1016/j.jhsg.2022.11.001
      Wartenberg syndrome can occur when external factors compress the superficial radial nerve. It can also be due to anatomic variations, such as a split brachioradialis tendon entrapping the nerve. This case report describes a unique example of a professional baseball player diagnosed with Wartenberg syndrome who was later found to have a split brachioradialis tendon during surgical management. It is an important addition to the field of hand surgery since, to our knowledge, we have not identified such a rare case concerning a professional athlete previously described in the literature.

      Key words

      Compression of the superficial branch of the radial nerve (SRN) was first described by Dr Robert Wartenberg in 1932.
      • Ikiz Z.A.
      • Uçerler H.
      Anatomic characteristics and clinical importance of the superficial branch of the radial nerve.
      Originally termed cheiralgia paresthetica because of its parallels with the previously described meralgia paresthetica, Wartenberg syndrome, as it is now named, can be caused by either external sources (eg, watches or handcuffs) or anatomic variations. This disorder is most commonly the result of compression of the superficial radial nerve by the fascia dividing the brachioradialis and extensor carpi radialis longus tendons.
      • Turkof E.
      • Puig S.
      • Choi S.S.
      • Zöch G.
      • Dellon A.L.
      The radial sensory nerve entrapped between the two slips of a split brachioradialis tendon: a rare aspect of Wartenberg’s syndrome.
      However, in rare cases, the nerve entrapment can also be due to a split brachioradialis tendon. Turkof et al
      • Turkof E.
      • Puig S.
      • Choi M.S.
      • Schilhan R.
      • Millesi H.
      • Firbas W.
      Superficial branch of the radial nerve emerging between two slips of a split brachioradialis muscle tendon: a variation of possible clinical relevance.
      looked at 143 patients with confirmed Wartenberg syndrome who received SRN release and found a split brachioradialis tendon in 7 (5%) of them. Although entrapment of the superficial radial nerve is well described in the literature, to our knowledge, very few reports exist on this anatomic variant as a cause. Here we present a case that reports a professional baseball player with a diagnosis of this disorder who was subsequently found to have a split brachioradialis tendon during surgical management.

      Case Report

      A 22-year-old minor league baseball player presented to our clinic complaining of a burning sensation in the middistal forearm that radiated toward his dorsoradial hand while pitching. The issue had started approximately 9 months earlier. However, he recently started implementing a new slider technique that led to exacerbation of the pain. This was initially treated as tendonitis and then de Quervain disease, but after an unsuccessful corticosteroid injection, the case was referred to an outside hand surgeon for evaluation. Written informed consent was obtained from the patient for publication of this case report and accompanying images.
      The patient described intermittent burning and pain, approximately 9-cm proximal from the lister tubercle. Pronation, ulnar deviation, and flexion maneuver failed to elicit paresthesia. Paresthesia was reproducible with active loading of the wrist when in pronation, ulnar deviation, and flexion. These findings were concerning for a Wartenberg syndrome diagnosis. A combination of anesthetic and corticosteroid was injected into the area of discomfort and the patient was instructed to return to the clinic in 2 weeks for reevaluation. Two weeks later, the patient reported mildly improved symptoms. Because of his initial improvement, conservative management was to be continued with nerve glide exercises and the eventual return to progressive pitching program. However, despite the patient’s initial improvement, he returned 3 months later with continued symptoms. Therefore, surgical management was recommended.
      During the procedure, a 6-cm incision was centered over a location 9-cm proximal to the radial styloid. During initial dissection to the interval of the brachioradialis and extensor carpi radialis longus, it was noticed that the superficial radial nerve was emerging in between a split tendon of the brachioradialis and was being compressed (Figure 1, Figure 2). The most dorsal aspect of the tendon was excised, and the path of the nerve was followed distally to its first split to ensure it remained subcutaneous, and then proximally to identify other areas of compression (Fig. 3). An intraoperative pronation, ulnar deviation, and flexion maneuver revealed compression of the nerve by the main muscle belly of the brachioradialis (Fig. 4). A 1 × 3–cm section was excised to prevent scarring of the nerve. On a repeat pronation, ulnar deviation, and flexion examination, no compression was noted. Figure 5 depicts a diagram of forearm anatomy.
      Figure thumbnail gr1
      Figure 1Split BR tendon in situ. BR, brachioradialis.
      Figure thumbnail gr2
      Figure 2Split BR tendon with the superficial radial nerve entrapped beneath. BR, brachioradialis.
      Figure thumbnail gr3
      Figure 3Fully separated BR tendon slips demonstrating the site of entrapment. BR, brachioradialis.
      Figure thumbnail gr4
      Figure 4Removed accessory BR slip and the freed superficial radial nerve. BR, brachioradialis; ECRL, extensor carpi radialis longus.
      Figure thumbnail gr5
      Figure 5Forearm anatomy diagram. Image adapted from Netter's Concise Orthopaedics.
      The patient was then placed in a plaster orthosis for 2 weeks, followed by a removable orthosis for 2 weeks, working on periodic active partial range of motion. Four weeks after surgery, he started passive full range of motion along with progressive strengthening.
      At his 6-week follow-up visit, the patient presented with full range of motion, a negative Tinel sign, and no dysesthesias, with passive flexion, ulnar deviation, and pronation. Two weeks later, the patient graduated passive range of motion rehabilitation and started his observed throwing program. He completed all therapeutic warm-up and rehabilitation activities as directed without issue. The patient is now 6 months after surgery and back to full participation with no restrictions in minor league games as a pitcher.

      Discussion

      Peripheral neuropathies are a group of conditions that alter quality of life and the ability to work. Symptoms of peripheral compression neuropathy include paresthesia, dysesthesia, and weakness depending on the nerve that is being compressed. Etiologies are often divided into 2 categories as follows: acute traumatic crushing injuries and chronic compression of a nerve at sites of anatomic narrowing along the nerves course. The SRN runs superficial to the supinator and deep to the brachioradialis at the level of the forearm.
      • Tapadia M.
      • Mozaffar T.
      • Gupta R.
      Compressive neuropathies of the upper extremity: update on pathophysiology, classification, and electrodiagnostic findings.
      ,
      • Dang A.C.
      • Rodner C.M.
      Unusual compression neuropathies of the forearm, part I: radial nerve.
      ,
      • Dellon A.L.
      • Mackinnon S.E.
      Radial sensory nerve entrapment in the forearm.
      • Thompson R.G.
      • Dhulipala S.C.
      • Lourie G.M.
      Dysfunction of the lateral branch of the superficial radial nerve associated with radial collateral ligament injuries of the thumb metacarpophalangeal joint: a case series with cadaveric dissections.
      The SRN has been described as piercing the deep fascia between the middle and distal thirds of the forearm at 6.03, 9.0, and 9.2–cm proximal to the radial styloid and from there supplies the hand with its terminal branches.
      • Abrams R.A.
      • Brown R.A.
      • Botte M.J.
      The superficial branch of the radial nerve: an anatomic study with surgical implications.
      ,
      • Auerbach D.M.
      • Collins E.D.
      • Kunkle K.L.
      • Monsanto E.H.
      The radial sensory nerve. An anatomic study.
      These terminal branches supply innervation to the dorsoradial and dorsoulnar portion of the thumb and the dorsoradial portion of the hand and index and middle fingers proximal to the distal interphalangeal joint.
      • Tapadia M.
      • Mozaffar T.
      • Gupta R.
      Compressive neuropathies of the upper extremity: update on pathophysiology, classification, and electrodiagnostic findings.
      Superficial branch of the radial nerve compression is initially managed conservatively when appropriate with rest, activity modification, nonsteroidal anti-inflammatory drugs, injections, and orthoses. When conservative treatment has failed for greater than 6 months, operative management is considered in the form of decompression of the nerve. The anatomic variant discussed here was diagnosed intraoperatively after failure of conservative treatment. Although not used here, it should be noted that ultrasonography during physical examination maneuvers has been effective at demonstrating compressive neuropathies prior to surgical management. The use of high resolution sonographic probes during the pronation, ulnar deviation, and flexion maneuver could have proven useful to obtain a better understanding of the variant pathology prior to surgical intervention. Spontaneous resolution of symptoms is common with conservative management.
      In conclusion, the purpose of this case report is to describe the history and physical examination of a minor league baseball player who failed conservative treatment for SRN compression and was found to have split brachioradialis tendons causing entrapment. This is a rare anatomic variation that has been mentioned but rarely described in the literature and, to our knowledge, never in a high-level professional athlete. Turkoff et al
      • Turkof E.
      • Puig S.
      • Choi M.S.
      • Schilhan R.
      • Millesi H.
      • Firbas W.
      Superficial branch of the radial nerve emerging between two slips of a split brachioradialis muscle tendon: a variation of possible clinical relevance.
      demonstrated that the dorsal, more ulnar, slip of brachioradialis was smaller and likely to be more formidable to resection without complications of adhesions, recurrent compression, and/or loss of postoperative strength. The uncomplicated postoperative course further supports these claims.

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