The safety and accuracy of various carpal tunnel injection techniques.

PURPOSE: Carpal tunnel (CT) syndrome continues to be a commonly treated hand pathology. We aimed to evaluate several CT injection techniques for (1) spatial accuracy within the CT and (2) risk of median nerve (MN) injury. Our purpose was to evaluate for any significant differences in accuracy of needle placement within the carpal tunnel and final distance between the needle tip and the MN with each technique. METHODS: Fifteen fresh frozen cadaveric arms were used for this study. Six different injection techniques for CT injection were performed on each specimen, including palmaris longus, ulnar to flexor carpi radialis, trans-flexor carpi radialis, volar radial, volar ulnar, and direct through the palm techniques. After needle placement, a standard open CT release was performed to assess for accuracy of placement within the CT and measure needle position in relation to the MN and other anatomic structures. RESULTS: Accurate intra-CT needle placement was seen in 91% of injections. While there was no significant difference between injection techniques for distance to nearest tendon (p = 0.1531), the trans-flexor carpi radialis (tFCR), volar radial (VR), and volar ulnar (VU) techniques consistently provided the greatest intra-CT distance from needle tip to median nerve (p = 0.0019). The least incidence of intraneural needle placement was found with the tFCR and VR approaches. CONCLUSION: All six injection techniques reliably enter the CT space. The lowest risk to the MN was found with tFCR and VR techniques, and we recommend these techniques for safe and effective needle placement to avoid iatrogenic intraneural injection. LEVEL OF EVIDENCE: Level V: Cadaveric Study.

Ulnar two-point discrimination following endoscopic carpal tunnel release.

Carpal tunnel syndrome is median nerve symptomatic compression at the level of the wrist, characterized by increased pressure within the carpal tunnel and decreased nerve function at the level. Carpal tunnel release decreases pressure in Guyon's canal, via open techniques, with symptom and two-point discrimination improvement in the ulnar nerve distribution. We hypothesize that endoscopic carpal tunnel release improves two-point discrimination in the ulnar nerve distribution as well. This study includes 143 patients who underwent endoscopic carpal tunnel release between April 2016 to June 2019 in a single, community-based teaching hospital. A comprehensive retrospective chart review was performed on patient demographics, pre- and post-operative two-point discrimination test results, and complications. The effects of sex, age, and diabetes mellitus in the ulnar and median nerve territories with two-point discrimination tests were analyzed. As well as the differences in two-point discrimination among patient's based on their smoking status. There were significant post operative improvements in both the median (7.7 vs 4.4 mm, p < 0.001) and ulnar (5.7 vs 4.1 mm, p < 0.001) nerve territories. Smoking status, sex, age and diabetes did not significantly affect two-point discrimination outcomes. In conclusion the endoscopic release of the transverse carpal ligament decompresses the carpal tunnel and Guyon's canal, demonstrating improvement in two-point discrimination in both the ulnar and median nerve distributions.

El síndrome de túnel carpiano es la compresión sintomática del nervio mediano al nivel de la muñeca. Se caracteriza por un aumento de presión dentro del túnel y una disminución de la función del nervio a ese nivel. La liberación del túnel carpiano descomprime el canal de Guyon, con mejoría sintomática y en la prueba de discriminación de dos puntos en la distribución del nervio cubital. Hipotetizamos que la liberación endoscópica mejora de la misma manera en la distribución del nervio cubital. Este trabajo incluye 143 pacientes que tuvieron liberación endoscópica del túnel carpiano entre abril del 2016 y junio del 2019 en un hospital Universitario de la comunidad. Se evaluaron retrospectivamente las historias clínicas para los datos demográficos, los resultados pre y post quirúrgicos en la prueba de discriminación de dos puntos y complicaciones. Se analizaron los efectos del sexo, edad, tabaco y diabetes en los resultados de la prueba de discriminación de dos puntos para los nervios cubital y mediano. Hubo mejoría significativa post quirúrgica en la prueba de discriminación de dos puntos para los nervios mediano (7.7 vs 4.4 mm, p < 0.001) y cubital (5.7 vs 4.1 mm, p < 0.001). Fumadores, sexo, edad, y diabetes no afectaron de forma significativa. Concluimos que la liberación endoscópica del ligamento transverso del carpo descomprime el túnel carpiano y el canal de Guyon con mejoría en la prueba de discriminación de dos puntos para los nervios cubital y mediano.

Ulnar two-point discrimination following endoscopic carpal tunnel release / La liberación endoscópica del túnel carpiano y la prueba de discriminación de dos puntos del nervio cubital

Abstract Carpal tunnel syndrome is median nerve symptomatic compression at the level of the wrist, characterized by increased pressure within the carpal tunnel and decreased nerve function at the level. Carpal tunnel release decreases pressure in Guyon's canal, via open techniques, with symptom and two-point discrimination improvement in the ulnar nerve distribution. We hypothesize that endoscopic carpal tunnel release improves two-point discrimination in the ulnar nerve distribution as well. This study includes 143 patients who underwent endoscopic carpal tunnel release between April 2016 to June 2019 in a single, community-based teaching hospital. A comprehensive retrospective chart review was performed on patient demographics, preand post-operative two-point discrimination test results, and complications. The effects of sex, age, and diabetes mellitus in the ulnar and median nerve territories with two-point discrimination tests were analyzed. As well as the differences in two-point discrimination among patient's based on their smoking status. There were significant post operative improvements in both the median (7.7 vs 4.4 mm, p < 0.001) and ulnar (5.7 vs 4.1 mm, p < 0.001) nerve territories. Smoking status, sex, age and diabetes did not significantly affect two-point discrimination outcomes. In conclusion the endoscopic release of the transverse carpal ligament decompresses the carpal tunnel and Guyon's canal, demonstrating improvement in two-point discrimination in both the ulnar and median nerve distributions.

Resumen El síndrome de túnel carpiano es la compresión sintomática del nervio mediano al nivel de la muñeca. Se caracteriza por un aumento de presión dentro del túnel y una disminución de la función del nervio a ese nivel. La liberación del túnel carpiano descomprime el canal de Guyon, con mejoría sintomática y en la prueba de discriminación de dos puntos en la distribución del nervio cubital. Hipotetizamos que la liberación endoscópica mejora de la misma manera en la distribución del nervio cubital. Este trabajo incluye 143 pacientes que tuvieron liberación endoscópica del túnel carpiano entre abril del 2016 y junio del 2019 en un hospital Universitario de la comunidad. Se evaluaron retrospectivamente las historias clínicas para los datos demográficos, los resultados pre y post quirúrgicos en la prueba de discriminación de dos puntos y complicaciones. Se analizaron los efectos del sexo, edad, tabaco y diabetes en los resultados de la prueba de discriminación de dos puntos para los nervios cubital y mediano. Hubo mejoría significativa post quirúrgica en la prueba de discriminación de dos puntos para los nervios mediano (7.7 vs 4.4 mm, p < 0.001) y cubital (5.7 vs 4.1 mm, p < 0.001). Fumadores, sexo, edad, y diabetes no afectaron de forma significativa. Concluimos que la liberación endoscópica del ligamento transverso del carpo descomprime el túnel carpiano y el canal de Guyon con mejoría en la prueba de discriminación de dos puntos para los nervios cubital y mediano.