Ultrasound and Anatomical Study of Accessing the Nerves in the Knee by Fascial Planes.

The fascia is an undifferentiated mesenchymal tissue related to the peripheral nerves. Both can be identified by ultrasound, which is useful when performing peripheral nerve blocks. However, there is no unanimity about the approaching point of each nerve, nor is there a consensus on how to name the appropriate infiltration zone, although the paraneural zone is frequently mentioned. The aims of this study were to determine if ultrasound is accurate for identifying the fascial planes and the paraneural space of the nerves in the knee, infiltrating them, and achieving a correct anatomical diffusion, as well as for establishing access routes to avoid intraneural infiltration. The study was performed in 16 cryopreserved lower extremities of the dissection room of the Faculty of Medicine and Health Sciences, University of Barcelona. Nerves of the knee were injected with colorant guided by ultrasound after they were visualized. Correct location of the nerves by ultrasound was achieved in 98.75% of the cases, correct visualization of the needle by ultrasound in 82.5%, the hypoechogenic image around the nerve after infiltration in 82.5%, and a correct paraneural infiltration in 76.25% of cases. With these results, we can conclude that high-definition ultrasound enables location of the peripheral nerves and adjacent structures as well as the fasciae that surround them, and therefore allows performance of infiltrations in the paraneural spaces.

Human shoulder anatomy: new ultrasound, anatomical, and microscopic perspectives.

This study aimed to describe the shoulder anatomy, together with the anatomical relationships in adults and early stages of development. The shoulder muscles were studied from ultrasound, anatomical, and microscopic perspectives in a sample of 34 human shoulders. Thickness measurements were taken of the tendons and fasciae of the subscapularis, long head tendon of the biceps brachii, supraspinatus, infraspinatus, and teres minor. Ultrasound and dissection techniques are strongly correlated. However, the measurements obtained from the dissection technique were superior to those obtained from the ultrasound in all cases, except for the thickness of the long head tendon of the biceps brachii, the teres minor tendon, and the fascia thickness of the infraspinatus. In addition, the study of shoulder anatomy revealed no differences between females and males. Relevant findings from dissection included a clear overlap between the infraspinatus and supraspinatus, which shared tendon fibers, and a similar connection between the transverse ligament of the long head tendon of the biceps brachii and the subscapularis, which created a more interconnected shoulder function. The study of the anatomical measurements shows an underestimation of the shoulder measurements in the ultrasound compared with the dissection technique, but a high correlation between the measurements made by the two techniques. We present reference values for the tendon and fascia thicknesses of the rotator cuff, with no differences observed by gender. The relationships between shoulder structures described in the anatomical study imply as well that, in the event of an injury, adjacent tissues may be affected. This extended information may facilitate future optimal clinical explorations.

Is interfascial block with ultrasound-guided puncture useful in treatment of myofascial pain of the trapezius muscle?

OBJECTIVES: Ultrasound-guided puncture is indispensable for the injection of local anesthetic in the interfascial space, the space between 2 muscle fasciae. Interfascial infiltration or block may be useful in treating myofascial pain in the trapezius muscle. METHODS: (1) In 5 cadavers, we studied the diffusion of a physiological saline and latex solution in the interfascial space of the upper muscles of the back, and performed a histological study of the fasciae. (2) We performed an interfascial block in 25 patients with myofascial pain in the trapezius muscle. Depending on the trigger point location, the block was performed between the trapezius and the levator scapulae or between the trapezius and the rhomboideus major. RESULTS: In all cadavers, anatomical dissection showed the latex in the interfascial space. The histological study confirmed the presence of nerve structures in the fasciae and in the interfascial space itself. Pain was assessed in all patients on a visual analog scale (VAS) before and after the injection (at rest and in motion). Preinjection: mean VAS 6.4 (at rest) and 7.6 (in motion). Postinjection: mean VAS 1 (at rest) and 1.6 (in motion). DISCUSSION: The anatomical, histological, and ultrasound findings in the cadaver study confirmed the diffusion of the solution in the interfascial space. Study in patients confirms that the interfascial block in the back musculature can be as effective as in the abdominal musculature. The presence of nerve structures in this space, confirmed by the histological study, seems to explain the pain relief reported by the patients with this interfascial technique.

How to avoid injuries of the superior gluteal nerve.

BACKGROUND: Injuries to the superior gluteal nerve are a common complication in hip replacement surgery. They can be avoided with a good anatomical knowledge of the course of the superior gluteal nerve. METHODS: We dissected 29 half pelvises of adult cadavers. The distance and the angle from the entry points of branches of the superior gluteal nerve into the deep surface of the gluteus medium and minimus muscles to the midpoint of the superior border of the greater trochanter were measured. RESULTS: The dissections revealed that the nerve divided into 2 branches (86.20%) or 3 branches (13.8%). The more caudal branch was responsible for innervation of the tensor fascia latae. CONCLUSIONS: A 2-3-cm safe area above the greater trochanter is appropriate to prevent nerve damage.