Sciatic Nerve Block

[DreamLover]

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Total opinion poll:

What is everyone's favorite way to do a Nerve Stim/Landmark only Sciatic block?

Posterior, Lateral, Anterior? Success Rates? Favorite landmarks? Great tips and suggestions?

I personally am a big fan of the anterior approach...maybe it's laziness for not wanting to flip the pt after my femoral block, but I have had pretty good luck for knee down with the anterior approach and when it works...it's so quick and easy!

 

[Ketafol20]

Ditto on the Anterior approach.

 

[TrustMe]

Never done an anterior approach so I can't speak to that (although I would love to learn them, especially for saving time instead of trying to turn a fat pt. lateral). I prefer lateral position with the classic approach (greater trochanter and PSIS). I have yet to have one fail (although admittedly I have not done tons of these as our joint guys did not like them for TKA's, usually only did them for TKA post-op if the pt. had pain after a fully functional femoral block). I had a 15cm needle buried in a ladies butt and almost abandoned it when I got a twitch on my last pass. Pain free and sleeping 15 minutes later. This was a lady with significant pain with a fully functioning femoral catheter that was placed pre-operatively. I like sciatics and think they are great blocks. Would like to learn anterior approach and would have liked to do more sub-gluteal U/S guided during residency.

 

[DreamLover]

Never done an anterior approach so I can't speak to that (although I would love to learn them, especially for saving time instead of trying to turn a fat pt. lateral). I prefer lateral position with the classic approach (greater trochanter and PSIS). I have yet to have one fail (although admittedly I have not done tons of these as our joint guys did not like them for TKA's, usually only did them for TKA post-op if the pt. had pain after a fully functional femoral block). I had a 15cm needle buried in a ladies butt and almost abandoned it when I got a twitch on my last pass. Pain free and sleeping 15 minutes later. This was a lady with significant pain with a fully functioning femoral catheter that was placed pre-operatively. I like sciatics and think they are great blocks. Would like to learn anterior approach and would have liked to do more sub-gluteal U/S guided during residency.

For me, I don't mind going lateral in a normal to thin sized person, but in the heavier peeps, it's harder to properly ID the landmarks and everything just falls and it so easily pushed and moved in the wrong directions...it's like my nemesis

 

[sevoflurane]

Anterior... Hands down. Nothing beats the efficiency of a femoral + ant. sciatic single prep. 4" stimuplex for both blocks (same needle). Needle insertion sites literally inches from ea. other. Both blocks easily done under 5 minutes... and that is being generous. If you want to preserve the hamstrings... then do a "high popliteal".... about 10-14 inches above the the pop fossa. (for tka's).

 

[Oggg]

1. Sevo, you mean 10-14cm I think
2. I've been doing sciatics with different approaches for a few months now. I'm still a beginner, but I've been pretty happy with the anterior approach -- I basically do a NS-technique, but I hold the US probe on top to pick my needle path and see if I can correlate twitches with an echogenic mass. Usually I just have to go straight down just barely medial to the femur. If I miss, I first redirect medially, externally rotate the femur a little, then I start redirecting laterally.
3. I've also had some good success with the parasacral/Monsour approach (lateral decub, combo with lumbar plexus blk). 3FB caudal to the PSIS, walk caudally off the bone if you hit it. NYSORA has a great article on the NS approach.
4. The Japanese anesthesia journal came out with a medial upper thigh approach to the sciatic which I'm working on. Supine pos with femur ext rotated, knee flexed, shorter distance, easier to US the nerve (with experience), can use the linear probe... But yeah, it requires an ultrasound and NS.

Anterior... Hands down. Nothing beats the efficiency of a femoral + ant. sciatic single prep. 4" stimuplex for both blocks (same needle). Needle insertion sites literally inches from ea. other. Both blocks easily done under 5 minutes... and that is being generous. If you want to preserve the hamstrings... then do a "high popliteal".... about 10-14 inches above the the pop fossa. (for tka's).

 

[sevoflurane]

Yep.... cm. about 3-4 inches above your classic pop. Everyone is a bit different, you just want to be well above the bifurcation of the sciatic. Low mid thigh.

Parasacral sciatics has the best coverage for hips as far as sciatics are concerned (vs. labbat/classical)

Parasacral + LP works very well. Again, for hips... you can prep at the same time.

LP alone works very well.

Regional is so much fun. 😀

 

[pgg]

If I miss, I first redirect medially, externally rotate the femur a little, then I start redirecting laterally.

[...]

4. The Japanese anesthesia journal came out with a medial upper thigh approach to the sciatic which I'm working on. Supine pos with femur ext rotated, knee flexed, shorter distance, easier to US the nerve (with experience), can use the linear probe... But yeah, it requires an ultrasound and NS.

Can you elaborate on the external femur rotation?

I didn't learn the anterior approach as a resident, and have been self-teaching myself. I've been starting with the patient supine, femur in a neutral position (not rotated). NYSORA's web site suggests internal rotation which makes a little more sense to me, as it seems more likely to get the lesser trochanter out of the way.

 

[Mman]

If I'm doing a femoral and sciatic, I do a classic sciatic in lateral position first and then roll them over to do the femoral. I find it's easier to move them from lateral to supine after they are sedated than the converse. I don't like doing anterior sciatics. I can. I'm just not as good at them as I am at a classic technique. The 30-60 seconds it takes me to do a classic approach generally balances out the extra 45 seconds of positioning time I waste between changing positions.

I've just never been a big fan of the anterior sciatic approach. I understand how it can be useful, I've just never had that level of skill with it. And since I'm fast as crap with everything else, it provides me no benefit to practice and get better at it.

 

[Oggg]

crap, you are correct, it should be internal rotation. In any case, I usually don't need to do any rotation.

Supine for both fem and sciatic is nice because it's 1 prep stick, 1 needle, 1 probe drape, 1 pair of sterile gloves. Eventually I want to master 4 techniques -- supine w/NS, posterior NS, anterior w/US, posterior w/US. I just started going to a surgicenter that doesn't have an US...

Can you elaborate on the external femur rotation?

I didn't learn the anterior approach as a resident, and have been self-teaching myself. I've been starting with the patient supine, femur in a neutral position (not rotated). NYSORA's web site suggests internal rotation which makes a little more sense to me, as it seems more likely to get the lesser trochanter out of the way.

 

[Oggg]

The nice thing about the anterior approach for me is that once you have contacted the femur, you have defined the lateral boundary of where the sciatic nerve can be. If you get no twitch you know you have to redirect medially. With other approaches I feel like if I miss, I might have to redirect in both directions, and I might lose track of where I've already needled in doing so.

For ppl who like posterior approaches, what is your strategy for fishing for the nerve if you don't get it on the first pass?