# proximal saphenous block



## sslovisone (Apr 11, 2012)

Has anyone heard of a proximal saphenous block that is placed in the hunter's canal?  Do I bill a 64447 or a 64450?


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## dwaldman (Apr 11, 2012)

This would be considered an other peripheral nerve and you would want to use 64450. Below I noticed they reference the adductor-canal as another name for the Hunter's canal which I found on an interent search describing innervation of the knee region.


Sensory innervation of the knee region
Literature search
Continuous adductor-canal-blockade for TKA and MR scans
Discussion
References
The cutaneous and articular sensory innervation of the knee region is complex and displays considerable variation.3 This innervation is derived from the femoral, the obturator and the sciatic nerves. In particular, the overlap of nerves to the knee joint is profound, and no portion of the capsule is supplied by a single nerve.4

The femoral nerve divides into an anterior and a posterior division immediately below the inguinal ligament. The anterior division gives off the anterior cutaneous branches, which consist of the intermediate and medial cutaneous nerves. The intermediate cutaneous nerve supplies the skin of the anterior surface of the thigh.5 It communicates with the medial cutaneous nerve and the saphenous nerve to form the patellar plexus,6 supplying the skin in front of the knee.7 The medial cutaneous nerve supplies the skin of the medial surface of the thigh.5 It joins to form the subsartorial plexus with branches of the saphenous nerve and the obturator nerve.6–7 The subsartorial plexus supplies the skin over the medial part of the knee.8 Horner and Dellon3 found that the most superficial constant branch innervating the medial aspect of the knee was the termination of the medial cutaneous nerve. The nerve was found travelling in the adductor canal (Hunter's canal) in 61% of the dissections.3

The posterior division of the femoral nerve gives off the saphenous nerve, and the nerves to the vastus lateralis, intermedius and medialis muscles.5,6 The articular branches of the femoral nerve all arise from these four nerves.4

The nerve to the vastus lateralis supplies the anterolateral portion of the knee capsule. The nerve to the vastus intermedius supplies the periost on the anterior part of femur. The nerve to the vastus medialis accompanies the saphenous nerve in the adductor canal, and supplies the anteromedial portion of the knee capsule.4

The saphenous nerve is a pure sensory nerve and the largest cutaneous branch of the femoral nerve. It leaves the femoral nerve proximally in the femoral triangle (Scarpa triangle). It then descends within the adductor canal and courses beneath the sartorius muscle with the femoral artery, beginning lateral to the artery, and then crossing to the medial side anterior to the artery just proximal of the lower end of the adductor magnus muscle. Further distally, the femoral artery departs from the sartorius muscle and becomes the popliteal artery lateral and deep to the muscle. At this location, the saphenous nerve continues its course under the sartorius muscle. The saphenous nerve supplies cutaneous areas over the anterior and medial side of the leg, ankle and foot. It joins the patellar plexus supplying the area over the patella and the subsartorial plexus supplying the area on the medial part of the thigh.6 Finally, it sends an articular branch to the knee joint, supplying the anterior inferior knee capsule.3

The obturator nerve divides into an anterior and a posterior branch when entering the thigh through the obturator foramen.6 There is a profound variation in the cutaneous innervation from the obturator nerve. Bouaziz et al.9 found that the cutaneous innervation from this nerve was absent in 17 out of 30 patients (57%). In six patients (20%), the obturator nerve supplied an area on the inferior and medial part of the thigh, and seven patients (23%) had a zone of hypoesthesia in the superior part of the popliteal fossa.

The anterior branch descends in front of the adductor brevis, and behind the pectineus and adductor longus muscles.6 It gives off muscular branches to adductor longus, gracilis, adductor brevis and sometimes pectineus. When present, the cutaneous branch supplies the skin over the lower medial side of the thigh.7 Several authors have described a frequent anastomosis of the anterior branch of the obturator nerve with the articular branch of the saphenous nerve in the adductor canal.3,4,10 In the study by Horner and Dellon,3 the anterior branch of the obturator nerve was found to contribute significantly to the perigenicular structures in five dissections (percentage not defined). The posterior branch descends between the adductor brevis and the magnus muscles. It perforates the distal part of the adductor magnus, which it supplies, and enters the adductor canal, before following the femoral artery, through the adductor hiatus, into the popliteal fossa.3–5 To our knowledge, no study in the literature has described at what level the posterior branch enters the adductor canal. The nerve anastomoses with branches of the tibial nerve and forms the popliteal plexus, which supplies the posterior aspect of the knee joint.3–4 This is described as being a relatively constant branch. According to Gardner,4 in those cases, where the posterior branch of the obturator nerve contributes no articular branch, he found the anterior branch anastomosing with saphenous in the adductor canal, sending off an articular branch. Thus, the articular contribution of the obturator nerve to the knee joint seems to be fairly constant, passing through the adductor canal, one way or the other.

The sciatic nerve contributes to the innervation of the posterior, lateral and medial aspects of the joint capsule and a number of the intra-articular structures, via genicular branches of both tibial and common peroneal components.4

In summary, our current knowledge demonstrates that there are many nerves that contribute to the sensory innervation of the knee region. Quite a few of these traverse the adductor canal: the saphenous nerve,5–7 the nerve to the vastus medialis (including the articular branch),4–7 the posterior branch of the obturator nerve,3–5 in most cases, the medial cutaneous nerve (61% of the dissections in Horner's study),3 and in some cases, the anterior branch of the obturator nerve as well.3–4,10 These nerves play a major role in the sensory innervation of the knee region. Because of the variability of this innervation, however, blockade of individual peripheral nerves for post-operative analgesia may give rise to various levels of pain relief.


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## ceesh2009 (Jul 19, 2012)

what happened with insurance when you billed for this block?


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