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To compare the visibility and procedural parameters between a standard spinal needle and a new laser-etched needle (LEN) in real-time ultrasonography guided lumbar medial branch access in a phantom of the lumbosacral spine.
We conducted a prospective single-blinded observational study at a rehabilitation medicine center. A new model of LEN was manufactured with a standard 22-gauge spinal needle and a laser etching machine. Thirty-two inexperienced polyclinic medical students performed ultrasonography-guided lumbar medial branch access using both a standard spinal needle and a LEN with scanning protocol. The outcomes included needle visibility score, needle elapsed time, first-pass success rate, and number of needle sticks.
The LEN received significantly better visibility scores and shorter needle elapsed time compared to the standard spinal needle. First-pass success rate and the number of needle sticks were not significantly different between needles.
A new LEN is expected to offer better visibility and enable inexperienced users to perform an ultrasonography-guided lumbar medial branch block more quickly. However, further study of variables may be necessary for clinical application.
Citations
To determine the midpoint (MD) of extensor hallucis longus muscle (EHL) and compare the accuracy of different needle electromyography (EMG) insertion techniques through cadaver dissection.
Thirty-eight limbs of 19 cadavers were dissected. The MD of EHL was marked at the middle of the musculotendinous junction and proximal origin of EHL. Three different needle insertion points of EHL were marked following three different textbooks: M1, 3 fingerbreadths above bimalleolar line (BML); M2, junction between the middle and lower third of tibia; M3, 15 cm proximal to the lower border of both malleoli. The distance from BML to MD (BML_MD), and the difference between 3 different points (M1–3) and MD were measured (designated D1, D2, and D3, respectively). The lower leg length (LL) was measured from BML to top of medial condyle of tibia.
The median value of LL was 34.5 cm and BML_MD was 12.0 cm. The percentage of BML_MD to LL was 35.1%. D1, D2, and D3 were 7.0, 0.9, and 3.0 cm, respectively. D2 was the shortest, meaning needle placement following technique by Lee and DeLisa was closest to the actual midpoint of EHL.
The MD of EHL is approximately 12 cm above BML, and about distal 35% of lower leg length. Technique that recommends placing the needle at distal two-thirds of the lower leg (M2) is the most accurate method since the point was closest to muscle belly of EHL.
Citations
To establish the safest approach to needle electrode insertion into the flexor pollicis longus (FPL) regarding possible needle injury to the superficial radial nerve (SRN) or radial artery by ultrasonography.
We evaluated 54 forearms of 27 healthy subjects. Three levels were defined in the forearm. Level 1 is the junction of the middle and distal third of the forearm, level 3 is the midpoint of forearm length, and level 2 is the midpoint between two levels. At each level, the distance between the most prominent point of the radius and the SRN (region A), the distance between the SRN and the radial artery (region B), and the depth from the skin surface to the FPL were measured.
The distance of region A was 1.20±0.41 cm in level 1, 1.62±0.45 cm in level 2, and 1.95±0.49 cm in level 3. The distance of region B was 1.02±0.29 cm in level 1, 0.61±0.24 cm in level 2, and 0.37±0.19 cm in level 3. The depth from the skin surface to the FPL was 0.92±0.20 cm in level 1, 1.14±0.26 cm in level 2, and 1.45±0.29 cm in level 3.
The safest needle insertion point to the FPL is the middle of the forearm within approximately 0.8 cm from the most prominent point of the radius. We recommend that the needle is inserted at the above point perpendicular to the skin surface until the needle meets the FPL at a depth of approximately 1.45 cm from the skin surface.
Citations