Volar Wrist Arthroscopy Portals Using the NanoScope Are Safer Than Traditional Arthroscopy.

Background: The NanoScope, given its smaller size, may be further from critical structures when establishing volar wrist arthroscopy portals compared to the traditional 2.7-mm arthroscope.

Methods: Ten fresh-frozen latex-injected cadaver specimens were utilized. The volar radial (VR) and volar ulnar (VU) portals were created using an inside-out approach. The volar radial midcarpal (VR-MC) and volar ulnar midcarpal (VU-MC) portals were created using an inside-out approach. The arm was then dissected under 3.5-mm loupe magnification. Digital calipers were used to measure the distance between the portals and the surrounding anatomic structures by two fellowship-trained hand surgeons.

Results: The median nerve was on average 1.6, 7.2, 1.8, and 5.6 mm away from the trochar for the VR, VU, VR-MC, and VU-MC, respectively. The median nerve fascia was pierced by the VR portal in one specimen. The radial artery, ulnar artery, and ulnar nerve were not pierced in any specimen. Compared to historical controls, for the VR-MC portal, the NanoScope was further from all critical structures, aside from the radial artery, and did not pierce any neurovascular structures. For the VU-MC portal, the NanoScope was further from the ulnar artery and median nerve and did not pierce any neurovascular structures.

Conclusion: In developing volar portals, after placing the cannula through the volar capsule from an inside-out approach, we recommend making a volar incision and dissecting the local anatomic structures to guard against injury. Compared to historical controls, the NanoScope was typically further from neurovascular structures.