Tracheal Mirror Image Artifact in Patients With Normal and Pathologic Tracheas

Ultrasonography is gaining popularity as a diagnostic imaging modality for airway pathology. Tracheal ultrasound (US) has several nuances that are important for clinicians, including imaging artifacts, which can be mistaken for pathology. Tracheal mirror image artifacts (TMIAs) occur when the US beam is reflected back to the transducer in a nonliner direction or with multiple timesteps. It has previously been believed that the convexity of the tracheal cartilage prevents mirror image artifacts, but in reality, the air column acts as an acoustic mirror and causes TMIA. We describe a cohort of patients with both normal and pathologic tracheas, all of whom have TMIA on the tracheal US. These artifacts are important to recognize, especially as the airway US becomes more commonplace.

Carpal Tunnel Release With Ultrasound Guidance: Intermediate-Term Clinical Outcomes and Magnetic Resonance Imaging Findings

Purpose

The purpose of this study was to report intermediate-term outcomes following carpal tunnel release using ultrasound guidance and wide-awake local anesthesia no tourniquet, including a subset of patients with preoperative and postoperative magnetic resonance imaging (MRI).

Methods

In this observational study, patients with carpal tunnel syndrome were treated with carpal tunnel release using ultrasound guidance and wide-awake local anesthesia no tourniquet in a procedure room at a single center. Main outcomes were complications; return to activity and work at 2 weeks; Quick Disabilities of the Arm, Shoulder, and Hand and Boston Carpal Tunnel Questionnaire scores through 6 months; and postoperative morphological changes of the transverse carpal ligament, median nerve, and carpal tunnel evaluated using MRI.

Results

No complications were reported among 65 patients (68% women, 96 wrists). By 2 weeks, 97% of patients returned to normal activity and 100% returned to work. Statistically significant improvements in Boston Carpal Tunnel Questionnaire symptom severity scale, Boston Carpal Tunnel Questionnaire functional status scale, and Quick Disabilities of the Arm, Shoulder, and Hand scores occurred by the 2-week follow-up interval and persisted at 6 months (all P < .001). Pre- and postoperative MRI scans were available for 13 patients (17 wrists) at the 3-month mean follow-up. Complete transverse carpal ligament transection was documented in all wrists. Key MRI findings included a 22% increase in carpal tunnel cross-sectional area at the hamate (P < .001), a 52% increase in median nerve cross-sectional area at the hamate (P < .001), an 18% reduction in median nerve signal intensity (P = .002), a 38% reduction in the flattening ratio of the median nerve at the hamate (P < .001), a 33% reduction in the flattening ratio of the median nerve at the pisiform (P < .001), a 20% reduction in the flattening ratio of the carpal tunnel at the hamate (P < .001), and a palmar shift of the median nerve relative to the hamate in all cases.

Conclusions

Carpal tunnel release using ultrasound guidance using wide-awake local anesthesia no tourniquet in a procedure room setting was safe, effective, and resulted in morphological changes that were consistent with carpal tunnel decompression as demonstrated by MRI.

Type of study/level of evidence

Therapeutic IV.