Narrow Results

The current study aimed to explore the anatomy of the dorsal radio-carpal ligament (DRC ligament) and to investigate the presence and histological structure of ulnar part of the DRC ligament.

Twenty cadaveric wrist joints were dissected and attachments of the DRC ligament and the newly described ulnar part of the DRC ligament were identified and noted. Samples of both ligaments were sent for histological examination.

The DRC ligament was identified in all 20 specimens with type I Mizuseki arrangement of fibres seen in 60% of wrists. The ulnar part of the DRC ligament was successfully identified in 18 of the 20 wrists. The histological observation of the ulnar part of the DRC ligament showed the highly uniform arrangement of collagen bundles typical of ligaments.

This study explores the anatomy of the DRC ligament and confirms the presence of the ulnar part of DRC ligament through histological analysis not undertaken in previous studies.

This anatomical study was designed to assess the distribution of a solution (injectate) made up using local anesthetic, steroid and dye into the carpal tunnel using a commonly used injection technique. Dissections were undertaken in 29 embalmed cadaveric wrists. The cadaveric specimens were dissected 24 hours after injection to observe the effect of time on diffusion patterns in both superficial and deep planes.

Eighteen of the 29 specimens showed the presence of the injectate in the superficial plane and three preferential patterns of distribution were noted in the deep plane: free in the carpal tunnel, exclusively in the tendon sheath and mixed.

This is the first study investigating the delayed diffusion pattern of injectate in the carpal tunnel and illustrates its variability. The findings of variable degree of superficial diffusion and different patterns of intracarpal spread help to offer some explanation regarding the variability of the response following carpal tunnel injection.

Background: The purpose of this study was to identify the optimal pin insertion point to minimize finger motion restriction for proximal phalangeal fixation in cadaver models.

Methods: We used 16 fingers from three fresh-frozen cadavers (age, 82–86 years). Each finger was dissected at the level of the carpometacarpal joint and fixated to a custom-built range of motion (ROM)-measuring apparatus after skin removal. The pin was inserted into the bone through four gliding soft tissues: the interosseous hood, dorsal capsule, lateral band, and sagittal band. Then, each tendon was pulled by a prescribed weight in three finger positions (flexion, extension, and intrinsic plus position). Changes in the metacarpophalangeal (MCP), proximal interphalangeal (PIP), and distal interphalangeal (DIP) angles were measured before and after pinning. We compared the differences between the insertion points using the Tukey-Kramer post hoc test.

Results: Placement of pins into the sagittal band significantly restricted MCP joint flexion, while placement into the dorsal capsule and lateral band significantly restricted PIP joint flexion. Only placement into the interosseous hood showed no significant difference in joint angles between the three finger positions compared to pre-pin insertion. There were no significant effects on MCP, PIP, and DIP joint extension.

Conclusions: The ROM of the MCP joint was obstructed due to pinning in most areas of insertion. However, pin insertion to the interosseous hood did not obstruct the finger flexion ROM compared to that of other gliding soft tissues; therefore, we believe that the interosseous hood may be a suitable pin insertion point for proximal phalangeal fixation.

Background: Motor branch of the ulnar nerve (MUN) injury during carpal tunnel surgery is rare and it should never be injured during carpal tunnel release (CTR). However, an iatrogenic injury of the MUN can cause catastrophic physical and mental suffering. The aim of our study is to understand the anatomy of the MUN in relation to carpal tunnel in order to prevent iatrogenic injury during CTR.

Methods: We dissected 34 fresh cadaver hands and located the MUN in relation to the anatomical axis used for carpal tunnel surgery. Possible mechanisms of injury and the vulnerable area of the MUN were determined along the dissection.

Results: The MUN turned towards the thumb distal to hook of hamate. It then travelled on the floor of the carpal tunnel which was formed by intrinsic hand muscles under flexor tendons. The nerve located at 29.39 ± 7.41, 35.01 ± 3.14 and 38.79 ± 4.03 mm (Mean ± SD) in the central axis of ring finger, the vertical axis of the third web-space and the central axis of middle finger respectively. The nerve’s turning point, 10.9 ± 2.63 mm distal to the centre of hook of hamate where it lies just below the level of the transverse carpal ligament.

Conclusions: Surgeons should be aware of the nerve’s location. Surgical dissection or passing of any surgical instruments around the hook of hamate should be done with care.

Level of Evidence: Level IV (Therapeutic)

Background: Percutaneous fixation of scaphoid fractures need accurate guide pin insertion. The emergence of computer-assisted navigation and robotic surgery may provide a promising solution to this problem.

Methods: This study presents the development of an automatic multi-degrees of freedom (DOF) surgical robot with computer-assisted navigation system, focusing on percutaneous scaphoid guide pin insertion. Using this device, along with a 3D fluoroscopy unit, we have conducted an experimental study on 10 cadavers for percutaneous scaphoid guide pin insertion to verify the feasibility and reliability of the system.

Results: The mean operative duration was 29.1 (SD 4.3) minutes. The cadavers required no more than two attempts to achieve desired wire placement, with the mean positioning-error being 2.0 (SD 0.3) mm and the mean angle-deviation 3.6 (SD 0.7)°. Throughout the study, a mean of 2.2 full-cycle fluoroscopy attempts was required for each cadaver during surgery, and no preoperative CT scan was needed.

Conclusions: The outcomes show that using the automatic surgical robot to perform the percutaneous scaphoid guide pin insertion is feasible and desired results can be achieved.