hronic dorsal wrist pain is a disabling clinical problem that may result from a variety of pathoetiologic processes, including arthritis, instability, capsular injury, dorsal wrist ganglia, and neuroma formation. [1][2][3][4][5][6][7] Regardless of etiology, pain mediation via the terminal branches of the posterior interosseous nerve appears to play an important role in the clinical syndrome of dorsal wrist pain. 2,3,8 Consequently, complete or partial wrist denervation has been used as palliative treatment of chronic dorsal wrist pain when curative or reconstructive procedures are not feasible. 2,3,6,8 Whereas complete wrist denervation requires multiple Jay Smith, MD, Marco Rizzo, MD, Jonathan T. Finnoff, DO, Yusef A. Sayeed, MD, MPH, MEng, Johan Michaud, MD, Carlo Martinoli, MD Received March 2, 2011, from
ORIGINAL RESEARCHObjectives-The purpose of this study was to determine whether sonography can identify the distal posterior interosseous nerve at the wrist.Methods-On the basis of previous anatomic descriptions, high-resolution musculoskeletal sonography was used in an attempt to identify the distal posterior interosseous nerve in the wrists of 20 unembalmed cadaveric specimens (11 male and 9 female; ages 54-98 years). High-frequency scanning (17-5 MHz) of the fourth dorsal extensor compartment revealed a small (1-3 mm) hypoechoic structure located on the compartment floor, presumed to represent the posterior interosseous nerve. Electronic calipers measured the distance between Lister's tubercle and this structure, as well as the structure's radial-ulnar width and volar-dorsal height. The presumed posterior interosseous nerves of 10 specimens were then injected with diluted colored latex using sonographic guidance. Subsequent dissection definitively identified the sonographically visualized and injected structure.Results-Dissection revealed latex within the posterior interosseous nerve in all 10 injected specimens, thus confirming that the sonographically visualized structure represented the distal posterior interosseous nerve. The nerve was identified sonographically in all 20 examined specimens, was located an average of 4.88 mm (range, 2.10-10.0 mm) ulnar to Lister's tubercle, and had an average width and height of 2.35 mm (range, 1.20-3.50 mm) and 1.01 mm (range, 0.80-1.40 mm), respectively.Conclusions-High-resolution sonography can reliably identify the distal posterior interosseous nerve within the fourth dorsal extensor compartment. Clinicians should consider formal evaluation of the posterior interosseous nerve in patients presenting with dorsal wrist pain syndromes. Future investigations should explore the potential role of sonographically guided percutaneous procedures directed at the posterior interosseous nerve.