Review Question - QID 4458

The 1-2 wrist arthroscopy portal is the only portal listed that places the superficial branch of the radial nerve (SBRN) at risk.

Wrist arthroscopy plays an important diagnostic and therapeutic role in injuries about the wrist, but carries a 2% complication rate. The 1-2 portal is placed between the ECRB and APL. Care must be taken when accessing this portal, due to reported injuries to the superficial branch of the radial nerve, as well as radial artery.

Kilic et al. dissected 6 cadavers to determine the course of the SBRN. They found that it was .9mm from the 1-2 portal at its closest, and that care should be taken when creating this portal given frequent variations in course.

Auerbach et al. dissected 20 cadavers to determine the course of the SBRN. In all specimens, the nerve arose between the brachioradialis and ECRL ~8cm proximal to the radial styloid. On average, 5.8 branches of the SBRN crossed the wrist joint. They found some variability within the course, and urge surgeons to be respectful of the nerve during dissection.

Tryfonidis et al performed a cadaveric study to determine the anatomic relation of dorsal wrist arthroscopy portals and superficial nerves. They found that the 1-2 portal was only 1.82 mm from the SBRN. Compared to the 3-4 portal, 4-5 portal, 6U portal and midcarpal portal, the 1-2 portal was the closest in proximity to any sensory nerve.

Illustration A shows the various portals used in wrist arthroscopy. Illustration B shows the relation of the SBRN to the various arthroscopic portals.

Incorrect Answers:
Answer 1: The 6U portal places the dorsal sensory branch of the ulnar nerve at risk.
Answer 2: The 6R portal places the dorsal sensory branch of the ulnar nerve at risk.
Answer 4: The MCU portal places the EDC and EDM tendons at risk.
Answer 5: The 4-5 portal places the EDC and EDM tendons at risk.