<p begin="00:00:13.825" end="00:00:16.649" style="s2">- The saphenous nerve block is useful for</p>
<p begin="00:00:16.649" end="00:00:19.962" style="s2">medial knee surgery, medial leg surgery,</p>
<p begin="00:00:19.962" end="00:00:22.415" style="s2">and medial ankle and foot surgery.</p>
<p begin="00:00:22.415" end="00:00:24.147" style="s2">The saphenous nerve is a continuation</p>
<p begin="00:00:24.147" end="00:00:27.430" style="s2">of the femoral nerve below the knee.</p>
<p begin="00:00:27.430" end="00:00:29.297" style="s2">This is a good block to do in conjunction</p>
<p begin="00:00:29.297" end="00:00:32.494" style="s2">with a popliteal sciatic<br />nerve block to give you</p>
<p begin="00:00:32.494" end="00:00:35.411" style="s2">complete anesthesia below the knee.</p>
<p begin="00:00:37.158" end="00:00:39.907" style="s2">To perform the saphenous nerve block,</p>
<p begin="00:00:39.907" end="00:00:42.744" style="s2">we typically use a linear probe.</p>
<p begin="00:00:42.744" end="00:00:44.619" style="s2">The linear probe allows us to get</p>
<p begin="00:00:44.619" end="00:00:48.107" style="s2">good resolution and<br />reasonable penetration.</p>
<p begin="00:00:48.107" end="00:00:50.931" style="s2">Typical settings for the<br />saphenous nerve block</p>
<p begin="00:00:50.931" end="00:00:54.366" style="s2">start between four and six<br />centimeters total depth,</p>
<p begin="00:00:54.366" end="00:00:58.533" style="s2">expecting the nerve to be<br />between two and four centimeters.</p>
<p begin="00:01:00.825" end="00:01:03.038" style="s2">Now the saphenous nerve is a small nerve,</p>
<p begin="00:01:03.038" end="00:01:05.284" style="s2">and we may not see it in everybody.</p>
<p begin="00:01:05.284" end="00:01:07.861" style="s2">In fact, most people we don't see it in.</p>
<p begin="00:01:07.861" end="00:01:10.493" style="s2">The reason we do a saphenous nerve block</p>
<p begin="00:01:10.493" end="00:01:15.037" style="s2">is that we don't take away<br />any quadriceps muscles,</p>
<p begin="00:01:15.037" end="00:01:19.499" style="s2">and so the patient will have<br />no quadriceps muscle weakness.</p>
<p begin="00:01:19.499" end="00:01:22.585" style="s2">To get a saphenous nerve, you<br />may also do a femoral block,</p>
<p begin="00:01:22.585" end="00:01:24.713" style="s2">but by doing a femoral block, you may</p>
<p begin="00:01:24.713" end="00:01:28.395" style="s2">or you will take out all your quadriceps.</p>
<p begin="00:01:28.395" end="00:01:31.233" style="s2">So this technique I'm going<br />over is a great technique</p>
<p begin="00:01:31.233" end="00:01:33.824" style="s2">for outpatient surgery, because their</p>
<p begin="00:01:33.824" end="00:01:36.555" style="s2">quadriceps muscle strength will be intact.</p>
<p begin="00:01:36.555" end="00:01:39.656" style="s2">This technique I'm using<br />is useful in elderly</p>
<p begin="00:01:39.656" end="00:01:44.161" style="s2">and obese patients because<br />we're using muscle landmarks</p>
<p begin="00:01:44.161" end="00:01:47.594" style="s2">rather than nerve or<br />other small landmarks.</p>
<p begin="00:01:47.594" end="00:01:51.121" style="s2">So we usually start about 10<br />centimeters above the knee.</p>
<p begin="00:01:51.121" end="00:01:53.994" style="s2">Put the probe on the<br />medial side of the leg.</p>
<p begin="00:01:53.994" end="00:01:55.796" style="s2">We can abduct the leg a little bit</p>
<p begin="00:01:55.796" end="00:01:58.879" style="s2">to give us better visualization here.</p>
<p begin="00:02:00.011" end="00:02:03.160" style="s2">Now when we put the probe on here,</p>
<p begin="00:02:03.160" end="00:02:06.312" style="s2">we like to start more anterior.</p>
<p begin="00:02:06.312" end="00:02:08.400" style="s2">This gives us a view of the femur,</p>
<p begin="00:02:08.400" end="00:02:12.567" style="s2">the hyperechoic stripe here,<br />as well as the vastus medialis.</p>
<p begin="00:02:13.895" end="00:02:18.037" style="s2">The vastus medialis can pretty<br />much be found in everybody.</p>
<p begin="00:02:18.037" end="00:02:21.156" style="s2">We're going to slide the<br />probe posterior next.</p>
<p begin="00:02:21.156" end="00:02:25.323" style="s2">The next muscle we'll come<br />across is the sartorius muscle.</p>
<p begin="00:02:27.335" end="00:02:31.002" style="s2">Now we see the vastus<br />medialis muscle ending</p>
<p begin="00:02:33.180" end="00:02:36.597" style="s2">and see the sartorius muscle in view now.</p>
<p begin="00:02:38.078" end="00:02:42.341" style="s2">There are many anatomical<br />differences in patient to patient.</p>
<p begin="00:02:42.341" end="00:02:45.497" style="s2">The saphenous nerve can run anterior</p>
<p begin="00:02:45.497" end="00:02:47.501" style="s2">to the sartorius muscle, posterior to the</p>
<p begin="00:02:47.501" end="00:02:49.996" style="s2">sartorius muscle, and I've even seen it</p>
<p begin="00:02:49.996" end="00:02:52.156" style="s2">piercing the sartorius muscle.</p>
<p begin="00:02:52.156" end="00:02:56.138" style="s2">So the whole key is, is that we will put</p>
<p begin="00:02:56.138" end="00:02:59.219" style="s2">our local anesthetic<br />below the sartorius muscle</p>
<p begin="00:02:59.219" end="00:03:02.041" style="s2">in order to get a good<br />saphenous nerve block.</p>
<p begin="00:03:02.041" end="00:03:05.611" style="s2">Most of the time we're<br />doing a field type block</p>
<p begin="00:03:05.611" end="00:03:09.000" style="s2">where we deposit the local<br />behind the sartorius muscle,</p>
<p begin="00:03:09.000" end="00:03:12.065" style="s2">and expect that that local<br />will get to the nerve,</p>
<p begin="00:03:12.065" end="00:03:13.696" style="s2">because these nerves can be difficult</p>
<p begin="00:03:13.696" end="00:03:17.295" style="s2">to see in obese or elderly patients.</p>
<p begin="00:03:17.295" end="00:03:19.517" style="s2">So now, our needle approach is</p>
<p begin="00:03:19.517" end="00:03:22.911" style="s2">gonna be using a 10 centimeter needle.</p>
<p begin="00:03:22.911" end="00:03:24.917" style="s2">This needle will be<br />inserted a few centimeters</p>
<p begin="00:03:24.917" end="00:03:27.750" style="s2">away from the probe in this angle.</p>
<p begin="00:03:28.848" end="00:03:30.890" style="s2">We like to see the<br />needle in a shallow plane</p>
<p begin="00:03:30.890" end="00:03:35.057" style="s2">and then advance it deeper<br />below the sartorius muscle.</p>
<p begin="00:03:36.949" end="00:03:41.087" style="s2">This block can also be performed<br />if the patient is prone,</p>
<p begin="00:03:41.087" end="00:03:44.938" style="s2">imagine my needle coming<br />from the other side.</p>
<p begin="00:03:44.938" end="00:03:47.155" style="s2">Typical volumes used here are between</p>
<p begin="00:03:47.155" end="00:03:51.544" style="s2">five and 20 milliliters of<br />local anesthetic; if a good</p>
<p begin="00:03:51.544" end="00:03:54.829" style="s2">nerve is seen, usually<br />represented by a hyperechoic</p>
<p begin="00:03:54.829" end="00:03:58.603" style="s2">structure, then I'll just<br />place five milliliters.</p>
<p begin="00:03:58.603" end="00:04:00.817" style="s2">Most patients, we do<br />not see the individual</p>
<p begin="00:04:00.817" end="00:04:03.559" style="s2">nerve here, and we will<br />place 10 milliliters</p>
<p begin="00:04:03.559" end="00:04:06.726" style="s2">as a type of field block in this area.</p>
<p begin="00:04:10.655" end="00:04:15.248" style="s2">Here, our needle is advancing<br />through the vastus medialis.</p>
<p begin="00:04:15.248" end="00:04:17.993" style="s2">We try to position the tip of the needle</p>
<p begin="00:04:17.993" end="00:04:20.203" style="s2">underneath the sartorius muscle,</p>
<p begin="00:04:20.203" end="00:04:24.472" style="s2">which is located to the<br />right of the screen.</p>
<p begin="00:04:24.472" end="00:04:26.846" style="s2">You can see the hyperechoic areas,</p>
<p begin="00:04:26.846" end="00:04:30.013" style="s2">some of which may represent the nerve.</p>
<p begin="00:04:31.296" end="00:04:35.313" style="s2">Our needle is now directly<br />below the sartorius muscle,</p>
<p begin="00:04:35.313" end="00:04:37.689" style="s2">and you can see the local anesthetic</p>
<p begin="00:04:37.689" end="00:04:41.498" style="s2">spreading below the sartorius muscle</p>
<p begin="00:04:41.498" end="00:04:44.165" style="s2">to track to the saphenous nerve.</p>

<p begin="00:00:07.382" end="00:00:09.372" style="s2">- [Voiceover] A linear array transducer</p>
<p begin="00:00:09.372" end="00:00:11.583" style="s2">with a nerve exam type is used to perform</p>
<p begin="00:00:11.583" end="00:00:14.256" style="s2">an ultrasound-guided<br />saphenous nerve block.</p>
<p begin="00:00:14.256" end="00:00:16.488" style="s2">The target depth is approximately</p>
<p begin="00:00:16.488" end="00:00:19.895" style="s2">one to three centimeters<br />in an 80 kilogram adult.</p>
<p begin="00:00:19.895" end="00:00:22.767" style="s2">The patient is positioned<br />in a supine position</p>
<p begin="00:00:22.767" end="00:00:26.181" style="s2">with the leg slightly abducted<br />and externally rotated.</p>
<p begin="00:00:26.181" end="00:00:29.113" style="s2">The transducer is placed<br />in the middle of the thigh</p>
<p begin="00:00:29.113" end="00:00:32.156" style="s2">in a transverse plane,<br />with the orientation marker</p>
<p begin="00:00:32.156" end="00:00:34.315" style="s2">directed to the patient's right.</p>
<p begin="00:00:34.315" end="00:00:36.942" style="s2">The leg is scanned medially to laterally</p>
<p begin="00:00:36.942" end="00:00:39.876" style="s2">to identify the<br />superficial femoral artery,</p>
<p begin="00:00:39.876" end="00:00:42.604" style="s2">which lies underneath<br />the sartorius muscle.</p>
<p begin="00:00:42.604" end="00:00:44.704" style="s2">The saphenous nerve can lie either</p>
<p begin="00:00:44.704" end="00:00:47.489" style="s2">anterior or posterior to the artery.</p>
<p begin="00:00:47.489" end="00:00:50.222" style="s2">The saphenous nerve may not be visible.</p>
<p begin="00:00:50.222" end="00:00:52.648" style="s2">If it is, it will appear as a bright,</p>
<p begin="00:00:52.648" end="00:00:55.461" style="s2">hyperechoic oval or triangular structure.</p>
<p begin="00:00:55.461" end="00:00:58.688" style="s2">The needle is positioned one<br />to two centimeters lateral</p>
<p begin="00:00:58.688" end="00:01:02.121" style="s2">to the transducer, and<br />advanced under the transducer.</p>
<p begin="00:01:02.121" end="00:01:04.989" style="s2">Local anesthetic is<br />injected incrementally,</p>
<p begin="00:01:04.989" end="00:01:07.315" style="s2">superficial and deep to the artery</p>
<p begin="00:01:07.315" end="00:01:10.482" style="s2">to complete the saphenous nerve block.</p>