Fascicular Anatomy of the Human Femoral

Nerve: Implications for Neural Prostheses Using Nerve Cuff

Electrodes

Adam Silva

Overview

•Procedure

•Results

•Use of results

The Study•The main point of this study was to learn

about the positioning and size of the femoral nerve and its branches throughout the thigh and to gather information regarding the order and amount of fascicles innervating the muscles in the thigh

•The information collected can then be used in the development of nerve-cuff electrodes used to restore movement to patients suffering from spinal cord injuries.

Anatomy of the Thigh

• Muscles:

• Vastus Lateralis

• Vastus Intermedius

• Vastus Medialis

• Rectus Femoris

• Sartorius

• Pectineus

Anatomy of the Thigh

• Nerves:

• Femoral Nerve

• Sartorius

• Rectus Femoris

• Vastus Lateralis

• Vastus Intermedius

• Vastus Medialis

• Pectineus

The Procedure

•The femoral nerve and all of its branches were removed from four female cadavers

•The right and left femoral nerves were removed from each cadaver

•The four subjects range from 87 to 99 years old

The Procedure

•In addition to cadavers, six male patients were studied in vivo

•These patients were undergoing vascular surgery and allowed the study to be done on them

•The ages of the patients ranged from 51-56 years old

The Results

•The compound femoral nerve was consistently located at the midpoint of the anterior superior iliac spine and pubic symphysis

The ResultsSpecimen Medial ::::::> ::::::> ::::::> ::::::> ::::::> ::::::> Lateral

1R Pect Sart M Cut Saph Vast Med Vast Int Vast Lat Rect Fem

1L --- Sart --- Saph Vast Med Vast Int Vast Lat Rect Fem

2R Pect M Cut Sart Saph Vast Med Vast Int Vast Lat Rect Fem

2L --- Sart --- Saph Vast Med Vast Int Vast Lat Rect Fem

3R --- Sart Saph M Cut Vast Med Vast Int Vast Lat Rect Fem

3L Pect M Cut Sart Saph Vast Med Vast Int Vast Lat Rect Fem

4R Sart Pect Saph M Cut Vast Med Vast Int Vast Lat Rect Fem

4L Pect M Cut Saph Vast Med Vast Int Vast Lat Rect Fem Sart

The Results• Fascicular anatomy varied slightly overall

between each specimen, but was identical for the vasti muscles

• The fascicles for the vasti muscles were located on the central, posterior portion of the femoral nerve

• The fascicles for the sensory and rectus femoris nerves were located laterally on the periphery of the thigh.

The Results• The fascicles from the sartorius nerve

varied more than the others and were found in either medial lateral or central portion of the femoral nerve

• The fascicles from the pectineus nerve were usually found anterior to the femoral nerve

• Overall the fascicular patterns in each specimen were relatively consistent

The Results

•It was found that the major nerve branches required for standing were centrally located and were also the most distal branches

•These nerves were the vastus lateralis, vastus intermedius, and vastus medialis

The Results

•The sensory nerves and nerves used for the process of standing up were located on the lateral and medial sides and were the proximal branches

•These included the m. cutaneous, saphenous, sartorius, and rectus femoris

Uses of the Study

•Most treatment of spinal cord injury involves functional electrical stimulation (FES)

•This involves the connection of electrodes to the muscle at nerve entry points and/or intramuscular electrodes inserted into the muscle belly

Uses of the study

•These methods are successful, but have many areas for improvement

•The procedure for these methods involves the implant of multiple electrodes in the thigh (at least one for each muscle innervated)

Uses of the Study• The sartorius and rectus femoris muscles are

important for the process of standing up, but are not needed for an individual to remain standing

• The muscles needed to stand are the vasti muscles

• Using the previously mentioned methods results in the contraction of other unneeded muscles like the sartorius and rectus femoris

• This limits the amount of time the individual can remain standing

Uses of the Study• This study has given hope for a new and

more successful way to innervate the muscles of someone suffering from a spinal cord injury

• A different method of innervating the muscles is by using the nerve cuff electrode

• This is an electrode that is cuffed around a nerve

Uses of the Study• By connecting to the femoral nerve the

electrode can be set up so that it will transmit current to the muscles only when they are needed for use

• This will prevent the contraction of unused muscles while standing and increase the length of time a patient can stand and walk

• With further innovation this method could bring many breakthroughs in rehabilitation for spinal cord injuries

Sources

• Gustafson, Kenneth, Gilles Pinault, Jennifer Neville, Ishaq Syed, and John Davis. "Fascicular Anatomy of the Femoral Nerve: Implications for Neural Prostheses Using Nerve Cuff Electrodes." Journal of Rehabilitation Research & Development 46. (2009): 973-984. Web. 1 Feb 2010. <http://www.rehab.research.va.gov/jour/09/46/7/Gustafson.html>.

• http://www.ifess.org/ifess99/Free%20Paper%20Session%202/hoffer.htm

• http://en.wikipedia.org/wiki/Functional_electrical_stimulation