Median Nerve and Carpal Tunnel Morphology Before and After Endoscopic Carpal Tunnel Release: A 6-Year Follow-up Study

Background: Our purpose was to describe structural and morphological features of the median nerve and carpal tunnel on magnetic resonance imaging (MRI) studies obtained before, immediately after, 6 weeks after, and 6 years after endoscopic carpal tunnel release (ECTR). Methods: In this prospective cohort study, 9 patients with a diagnosis of carpal tunnel syndrome (CTS) underwent ECTR. Standardized MRI studies were obtained before ECTR, immediately after ECTR, and 6 weeks and 6 years after surgery. Structural and morphological features of the median nerve and carpal tunnel were measured and assessed for each study with comparisons made between each time point. Results: All 9 patients had complete symptom resolution postoperatively. On the immediate postoperative MRI, there was a discrete gap in the transverse carpal ligament in all patients. There was retinacular regrowth noted at 6 weeks in all cases. The median nerve cross-sectional area and the anterior-posterior dimension of the carpal tunnel at the level of the hamate increased immediately after surgery and these changes were maintained at 6 years. Conclusions: We defined structural and morphological changes on MRI for the median nerve and carpal tunnel in patients with continued symptom resolution 6 years after ECTR. Changes in median nerve and carpal tunnel morphology that occur immediately after surgery remain unchanged at mid-term follow-up in asymptomatic patients. Established imaging criteria for CTS may not apply to postoperative patients. Magnetic resonance imaging appears to be of limited clinical utility in the workup of persistent or recurrent CTS.

Ultrasound-guided Cubital Tunnel Injection: Description of Technique and Accuracy in a Cadaver Model

ABSTRACT Introduction: Ulnar nerve (UN) and cubital tunnel morphology is influenced by elbow positioning, potentially compromising injection accuracy and placing the nerve at risk during cubital tunnel injection. Materials and methods: Based on previous anatomical studies of the cubital tunnel, a proof of concept injection model was developed. Eighteen above-elbow cadaver specimens were positioned in 45° elbow flexion and in neutral forearm rotation. The ultrasound transducer was oriented in the transverse plane, in-line with the medial epicondyle and olecranon tip, facilitating visualization of the UN and cubital tunnel. A 25-gauge needle oriented parallel to the ulna was inserted percutaneously at the midpoint between olecranon and epicondyle. The needle was advanced under ultrasound guidance to replicate injection and was secured. Open dissection confirmed its location. Results: 18/18 needle tips were within the cubital tunnel and no needles penetrated the UN. Discussion: Ultrasound-guided cubital tunnel injection, with the elbow in 45° flexion and with neutral forearm rotation was a safe and reliable technique in this cadaveric model. Future clinical studies may evaluate the efficacy of both diagnostic and therapeutic cubital tunnel injection. Nickel BT, Richard MJ, Cotterell I, Crosmer M, Ruch DS, Leversedge FJ. Ultrasound-guided Cubital Tunnel Injection: Description of Technique and Accuracy in a Cadaver Model. The Duke Orthop J 2017;7(1):43-45.

The comparison of tunnel corneal incision performed with femtosecond laser and keratome

Purpose. To compare and evaluate three-plane clear cornea incision (CCI) created with a femtosecond laser (Victus, B&L) and a metal keratome (2,2 mm steel). Materials and Mehtods. Sixty eyes of 60 patients were examined using anterior segment optical coherence tomography (AS-OCT) in early postoperative period (1 day, 1 week, 1 month) after phacoemulsification surgery. Images were used to measure incision length and incidence of epithelial or endothelial gaping, Descemet membrane detachment. Results. In the femtosecond group (34 eyes) the mean CCI length was 2.02 ± 0.05 mm versus keratome group (26 eyes) 2.04 ± 0.43mm. In laser group all incisions (100 %) were three-plane. In keratome group with manual incisions only 23 % were three-plane, 57.7 % were two-plane and 19.3 % were one-plane. Comparison of morphological features of femtosecond and keratome group: endothelial gaping 20.5 % versus 23 %, epithelial gaping 8.8 % versus 19 %. Descemet membrane detachment 17.6 % versus 34 %, respectively. Conclusion. All eyes in femtosecond group had three-plane profile visible on AS-OCT. Femtosecond CCIs showed better tunnel morphology compared to keratome group. Multiplane profile and minimal damaging of CCI will improve safety in the postoperative period.

Observations on the tunnel morphology of Heterocerus brunneus Melsheimer (Coleoptera: Heteroceridae) and its paleoecological significance

The burrow structures of Heterocerus brunneus Melsheimer and its larvae are described from both field (northeastern Kansas) and laboratory habitats. These are further interpreted in light of known North American heterocerid biology. Two important observations are that significant features of any one burrow varied with the consistency (especially the water content) of the substrate, and that different insects were making superficially similar burrows at the same field site. It would require exceptional preservation, or associated body parts, to positively identify fossil traces of these structures as heterocerid burrows, but their general pattern should be readily recognized as foraging traces in even the most degraded preservations.