Total Knee Arthroplasty and Anesthesia

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dhb said:
Isobaric: your solution stays concentrated at the site of injection
Hyperbaric: more spread less duration
Hypobaric acting longer? that's BS probably on par with iso because the difference in baricity is probably very small between these solutions
(Never used a hypobaric product)
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Anesth Analg. 2003 Aug;97(2):589-94, table of contents.
Isobaric versus hypobaric spinal bupivacaine for total hip arthroplasty in the lateral position.
Faust A1, Fournier R, Van Gessel E, Weber A, Hoffmeyer P, Gamulin Z.
Author information

Abstract
Total hip arthroplasty (THA) is frequently performed under spinal anesthesia using either isobaric or hypobaric anesthetic solution. However, these two solutions have never been compared under similar surgical conditions. In the present study, we compared the anesthetic and hemodynamic effects of isobaric and hypobaric bupivacaine in 40 ASA physical status I-II patients undergoing THA in the lateral decubitus position under spinal anesthesia. With operative side up, patients randomly received, in a double-blinded manner, a spinal injection of 3.5 mL (17.5 mg) of plain bupivacaine mixed with either 1.5 mL of normal saline (isobaric group) or 1.5 mL of distilled water (hypobaric group). Sensory level and degree of motor block were evaluated on the nondependent and dependent sides until regression to L2 and total motor recovery. Hemodynamic changes during the first 45 min after spinal injection, and the time between spinal administration and first analgesic for a pain score >3 (on a 0-10 scale) were noted. Demographic characteristics of both groups were comparable. Upper sensory level and maximal degree of motor block were comparable between the operative and nonoperative sides in each group and between corresponding sides in both groups. Compared with the isobaric group, in the hypobaric group there was a prolonged time to sensory regression to L2 on the operative side (287 +/- 51 versus 242 +/- 36 min, P < 0.004) and a prolonged time to first analgesic (290 +/- 46 versus 237 +/- 39 min, P < 0.001). No difference in quality of motor block was noted at the end of surgery. Hemodynamic changes were comparable. We conclude that for THA in the lateral position, spinal hypobaric bupivacaine seems to be superior to isobaric in that it prolongs the sensory block on the operative side and delays the use of analgesics after surgery without further compromising hemodynamic stability.

IMPLICATIONS:
For total hip arthroplasty in the lateral position, spinal hypobaric bupivacaine compared with isobaric prolonged sensory block at the operative side and delayed the time to first analgesic.
 
However, the results of the present study suggest that local anesthetic solutions considered isobaric, with a density even more than that of plain bupivacaine but less than that of the CSF, can show some signs of hypobaricity in patients kept in prolonged lateral position.

In summary, for patients undergoing orthopedic surgery in the lateral position under spinal anesthesia, 15 mg of hypobaric bupivacaine, compared with the identical dose of isobaric bupivacaine, prolonged sensory regression to L2, without further compromising systemic hemodynamic. We believe that 45 min longer duration of spinal block is clinically relevant and increases the reliability of hypobaric spinal anesthesia in this type of surgical procedure.
http://www.medwelljournals.com/fulltext/?doi=rjbsci.2009.222.226
 
Noyac said:
Blade, I know that studies are the best way of analyzing what we do. Without good studies we would not be where we are today. But with that being said, I also know that good outcomes at one facility may not translate to good outcomes at another. And that one facilities approach may not be adequate for another's. So what I tried to do at our facility is determine what works best for us. We have had no falls, very little PONV and what we consider very manageable pain control after our TKA's. So our goal was to improve on this which obviously appears to be difficult to improve on. I am always interested in new approaches. But I take every single one with a grain of salt. And when someone here or anywhere for that matter touts something as the next great approach I give it time to play out. Exparel was something I was very interested in. We got the right surgeon and we all were motivated. It didn't improve anything. To be more clear, it wasn't even up to our standard. I will say that I was impressed but not impressed enough to change anything I do. So I wonder, what was the results in the facilities that have bought into Exparel before they used it? It can't be all that good. Maybe it's because they have so many people on staff that the results are all across the board. Maybe we are different because we are all dr's doing our own cases and all well trained in all aspects of anesthesia. I don't know but all this talk of fancy blocks and local injection etc makes me wonder what results these groups are getting. We even have new grads come to us with all these fancy approaches and they slowly come to our side of the spectrum.

So tell me, what gives?
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1. Exparel is a long acting, Liposomal Bupivacaine based local anesthetic. It comes as a 1.3% concentration in a 20 ml bottle (266 mg).

2. Exparel diluted doesn't have quite the same duration as the undiluted product IMHO. Once the dilution exceeds 0.44% (total volume of 60 mls, 20 mls of Exparel diluted with NS or generic Bupivacaine) the drug begins to lose efficacy. IMHO, the duration of Exparel in the 0.44% concentration is in the 40-48 hour range typically.

3. Exparel diluted to 80 or 100 mls has a duration of analgesia in the 24 hour range which isn't that much better than the standard cocktail.

_______

Based on 1-3 is why most Ortho Surgeons don't get that much more "bang for their buck" over traditional local anesthetic cocktails; but, Diluted Exparel may help some on the margins.
The addition of a nerve block/blocks improves postop analgesia even further by providing better, consistent pain relief than Local injection alone.

So, while Exparel "failed your initial trial" once it gains FDA approval for nerve blocks and the drug is NOT diluted beyond 0.66% concentration the differences will become quite clear:
Exparel provides 48+ hours of postop analgesia when used for nerve blocks. My adductor Canal Blocks with Exparel (0.66%) and decadron PF 2mg have reliably produced 48 hours of analgesia. In one patient where I used Exparel for a ACB/Popliteal for a BKA the analgesia lasted 72 hours.

I agree with you that the traditional formula of Femoral/Sciatic or Femoral/Tibial has worked well for the past 30 years. So why fix something that isn't broken? The answer is early ambulation without motor weakness. The ACB/ipack allows mobilization on the day of surgery without muscle weakness while maintaining reasonably good VAS compared to the old, traditional gold standard.

So, "what gives" is my desire to evolve beyond the anesthesia of the late 1980s where a shotgun approach was used to provide postop analgesia for TKA into a 21st Century approach where a sniper bullet gives the desired benefits without any of the drawbacks.

I do agree that current techniques are not as good as the gold standard which is why some us continue to search for that elusive sniper bullet which will solve this problem. Until then I fully understand your approach to keep using the shotgun which provides consistent, reliable analgesia for TKA.
 
I hear ya. I would love a sniper round but like you said our snipers are not very accurate at this time.
 
regional-anesthesia-and-perioperative-outcomes-21-638.jpg
 
Noyac said:
But these are catheters. There is a big difference btw single shot FNB and catheters. We no longer do catheters for this reason.
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Would a patient be better off with a single shot Fem/Sciatic or Fem/Popliteal with Bupivacaine vs a ACB with Exparel combined with an iPACK (Exparel 0.66% used for both)?

The Exparel based blocks should last for 48-72 hours (admittedly slightly worse analgesia) while providing better ambulation (perhaps immediate).
 
BLADEMDA said:
Would a patient be better off with a single shot Fem/Sciatic or Fem/Popliteal with Bupivacaine vs a ACB with Exparel combined with an iPACK (Exparel 0.66% used for both)?

The Exparel based blocks should last for 48-72 hours (admittedly slightly worse analgesia) while providing better ambulation (perhaps immediate).
Click to expand...
You know, if I were to bet on this I would say that there would be a small advantage towards the ACB with Exparel. But I would also point out that the advantage would more than likely take many subjects to show this advantage and the expense would be much greater.
But I wouldn't bet very much on this either.
Until this is studied well and shows this advantage and I then give it a try, I will be a skeptic.
I believe that the pt selection and the practitioner are an important part of the outcome.
 
I now do good old fashion Bupivcaine Femoral + Low sciatic block + LMA GA 100% of the knees.
No intra-op opiates usually, No need for pain meds in PACU, and analgesia 48 hours.
Zero PONV, zero itching, and zero hypotension post-op.
Surgeons are old fashion and don't do early mobilization, only CPM until motor blocks are gone.
Patient's satisfaction is excellent too!
 
I assume the spinal + LMA was for billing purposes. Wouldn't you bill for a GA and then separately for the spinal for "post-op pain?"

We're all over the map and there is significant inter-clinician variability. We were recently asked by one of our joint surgeons to consider more or less standardizing to ACB with dexamethasone + spinal with duramorph, based on his anecdotal observation that his patients have less pain and may have shorter LOS with this approach. I have not yet adopted perineural dexamethasone and I'd love some of your opinions. My sense is that when it comes to randomized data in our top-tier journals, there is very little evidence that this is safe to do. Trials are small and totally underpowered to detect differences in safety outcomes. Moreover, there is at least one trial that showed reasonable equivalence in terms of block quality/duration between perineural and IV dexamethasone, and then with IV, you obviously get the other benefits of dexamethasone (PONV, primarily). So I guess my question for the group is, if not high quality randomized data, what evidence are you using to demonstrate the safety of perineural dexamethasone? I'd love to see some evidence that would make me more comfortable using it.

The duramorph issue is also a little tricky in that patients here require 24 hours of pulse oximetry, which can create long PACU waits and bed access issues. And, of course, there probably isn't any good evidence that intrathecal morphine is safe, either, so I can see my own hypocrisy.
 
You can bill an additional 3 units for duramorph, but other than that the case bills the same whether you do a spinal, a general, or both. The value a case has is based solely on the CPT code for the procedure + time + modifiers. Type of anesthesia doesn't matter. Block done for post op pain bills in addition to the base anesthetic.

As for safety of perineural dex, the pain guys have been squirting it onto epidural nerve roots for 30+ years. That's enough long term safety data for me. And IV dex is not equivalent, sorry, it just isn't.
 
The subject of the safety of perineural Dexamethasone has been discussed in detail on SDN. Based on the laboratory data I utilize "safe doses" of Perineural dexamethasone along with some additional Dexamethasone IV. If you want the longest single shot blocks possible consider adding low dose Dexamethasone (PF) along with Precedex to your bupivacaine mixture.


http://forums.studentdoctor.net/threads/decadron-iv-prolongs-nerve-blocks.1121811/

http://forums.studentdoctor.net/threads/premedication-dexamethasone.1184587/#post-17451225

http://forums.studentdoctor.net/thr...ngle-shot-nerve-blocks.1163042/#post-16952881 (please read this thread)
 
Last edited:
Planktonmd said:
I now do good old fashion Bupivcaine Femoral + Low sciatic block + LMA GA 100% of the knees.
No intra-op opiates usually, No need for pain meds in PACU, and analgesia 48 hours.
Zero PONV, zero itching, and zero hypotension post-op.
Surgeons are old fashion and don't do early mobilization, only CPM until motor blocks are gone.
Patient's satisfaction is excellent too!
Click to expand...

This is all good and great until the patient develops a foot drop postop. Guess who they are going to blame for the foot drop? When a Tourniquet is placed and inflated over the same nerve which has received a local anesthetic block the risk of "double crush" injury remains a concern.

Please do not misunderstand my post as I think your technique provides fantastic postop analgesia but it is not without increased malpractice risk to you vs the following:

1. High Sciatic block- EMG and conduction studies will put you in the clear if the patient develops a foot drop postop

2. Selective Tibial block using the medial approach- Low volume and the peroneal nerve is avoided/spared

3. Ipack Bock- zero chance of foot drop. sensory block

4. Sciatic or Popliteal block in the PACU postop after a neuro exam is conducted ruling out sciatic nerve injury.
 
Peroneal nerve palsy is a rare complication of total knee arthroplasty, with an estimated incidence of 0.3% to 10%.The etiology is postulated to be perioperative traction on the peroneal nerve rather than direct intraoperative trauma.Surgical risk factors for the development of peroneal palsy include preoperative valgus, previous upper tibial osteotomy or increased tourniquet time.
 
Peripheral neuropathies associated with the use of pneumatic tourniquet have a double pathophysiologic mechanism: compression and ischemia. Compression plays a more important role in the 2-3 first hours; after that the deficit of blood flow can cause permanent structural changes [18]. Nerve injury directly caused by compressive effect is mainly localized under the cuff [18], where the greatest local distortion is produced, and from this site tends to progress towards distal territories. Ischemia, however, although it affects the nerve as well, has a greater impact on muscle; in the early stages it is usually limited to the occluded area, while after four hours of tourniquet use its effects spread distally [1]. In this case report, considering the brief duration of tourniquet use (less than one hour), we think that only the first mechanism was involved in the development of sequelae.

Because tourniquet-related neural injury has been linked to mechanical rather than ischemic factors, mechanical stress merits the most focus for preventing nerve injury [19]. Tourniquet should be applied to the proximal part of the limb at the greatest circumference because the muscle bulk at that site is the greatest, and hence it affords a greater protection against nerve injury [20], and so, elderly persons with muscle atrophy and flaccid, loose skin might have a higher risk of nerve injury [21].

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3858884/
 
BLADEMDA said:
The subject of the safety of perineural Dexamethasone has been discussed in detail on SDN. Based on the laboratory data I utilize "safe doses" of Perineural dexamethasone along with some additional Dexamethasone IV. If you want the longest single shot blocks possible consider adding low dose Dexamethasone (PF) along with Precedex to your bupivacaine mixture.


http://forums.studentdoctor.net/threads/decadron-iv-prolongs-nerve-blocks.1121811/

http://forums.studentdoctor.net/threads/premedication-dexamethasone.1184587/#post-17451225

http://forums.studentdoctor.net/thr...ngle-shot-nerve-blocks.1163042/#post-16952881 (please read this thread)
Click to expand...

Okay, so I read that thread and found that you had like 75% of the posts there. Much of the data posted were in abstract form. When you stated that the data were "clearly" on your side for PN dexmedetomidine, you cited a study from almost 10 years ago that involved 31 rats. Maybe these adjuncts ARE safe, but what you showed me doesn't make the case. Saltydog's comments were somewhat compelling; decades of perineural steroid use establishes some kind of track record, I suppose.
 
cchoukal said:
Okay, so I read that thread and found that you had like 75% of the posts there. Much of the data posted were in abstract form. When you stated that the data were "clearly" on your side for PN dexmedetomidine, you cited a study from almost 10 years ago that involved 31 rats. Maybe these adjuncts ARE safe, but what you showed me doesn't make the case. Saltydog's comments were somewhat compelling; decades of perineural steroid use establishes some kind of track record, I suppose.
Click to expand...

dexamethasone may have a dose–related neurotoxicity, suggesting the lowest possible dose (1-2 mg per nerve block) should be used


when dexamethasone is combined with local anesthetics, the concentration of the former should not exceed 66.6 ug/mL, as the concentration of 133 ug/mL combined with ropivacaine 2.5mg/mL led to a significant increase in neuronal cytotoxicity

Brian Williams, MD
UPMC



http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3427651/ (please read)

Brian A. Williams, MD, MBA, Department of Anesthesiology, University of Pittsburgh School of Medicine, 200 Lothrop Street, A-1305 Scaife Hall, Pittsburgh, PA 15261, USA. Tel: 412-360-1602; Fax: 412-360-6609; E-mail:[email protected]
 
BLADEMDA said:
This is all good and great until the patient develops a foot drop postop. Guess who they are going to blame for the foot drop? When a Tourniquet is placed and inflated over the same nerve which has received a local anesthetic block the risk of "double crush" injury remains a concern.

Please do not misunderstand my post as I think your technique provides fantastic postop analgesia but it is not without increased malpractice risk to you vs the following:

1. High Sciatic block- EMG and conduction studies will put you in the clear if the patient develops a foot drop postop

2. Selective Tibial block using the medial approach- Low volume and the peroneal nerve is avoided/spared

3. Ipack Bock- zero chance of foot drop. sensory block

4. Sciatic or Popliteal block in the PACU postop after a neuro exam is conducted ruling out sciatic nerve injury.
Click to expand...
I don't disagree with you ... surprisingly 🙂
 
I don't think I've ever given 30 ccs of .5% bupi for a femoral NB in my entire life. Sorry, but these people need to be walking at the very least, the next morning.
There will be more pressure to get them mobilized on POD #0 as bundled payments and metric driven reimbursement arrives.... actually, it's already here.
 
While I'm not a fan, outpatient total joints has been happening in my community. I'm talking total hips and knees, not just TSA.
Guess who that benefits the most? Owners of these surgery centers. Really risky IMO.
 
sevoflurane said:
I don't think I've ever given 30 ccs of .5% bupi for a femoral NB in my entire life. Sorry, but these people need to be walking at the very least, the next morning.
There will be more pressure to get them mobilized on POD #0 as bundled payments and metric driven reimbursement arrives.... actually, it's already here.
Click to expand...
And that's why your analgesia will probably last 10 hours only 🙂
 
Planktonmd said:
And that's why your analgesia will probably last 10 hours only 🙂
Click to expand...

I don't do FNB anymore.

Spinal + duramorph + ACB = Ambulation once they get to the floor the same day of surgery. Discharge the next day when your FNB is starting to wear off. 😉
 
sevoflurane said:
I don't do FNB anymore.

Spinal + duramorph + ACB = Ambulation once they get to the floor the same day of surgery. Discharge the next day when your FNB is starting to wear off. 😉
Click to expand...
This is what I did in my previous setting, a busy private practice very heavy on ortho, but now I have the luxury of surgeons who don't insist on the patient being discharged in 24 hours and who don't care if they walk the night of surgery.
So I make sure they have zero pain and that they get no opioids for as long as possible.
I can tell you my patients are very happy.
 
Planktonmd said:
This is what I did in my previous setting, a busy private practice very heavy on ortho, but now I have the luxury of surgeons who don't insist on the patient being discharged in 24 hours and who don't care if they walk the night of surgery.
So I make sure they have zero pain and that they get no opioids for as long as possible.
I can tell you my patients are very happy.
Click to expand...
They may be happy but 2 days with a numb leg isn't ideal in most settings.
 
When I started in PP, all our orthos wanted GA + FNB cath. I suggested ACB's which they hadn't heard of and all of em poo poo'd me. Fast forward a year and half and somebody mus have gone to some conference because then all of a sudden they all wanted SAB + ACB with Exparel local infiltration (we didn't have the appropriate monitoring capabilities on the floor for Duramorph). Guesas who then had to teach the whole department how to do ACB's. Anyways, I will say that the pts did better after the switch. Less pain and earlier mobilization (Orthos wanted OOB on same day). There was a noticeable difference in pain scores - particularly posterior pain amongst the different orthopods which I assume was due to their Exparel injection technique. My guess is that the guys whose pts felt better were essentially doing a blind iPACK without realizing it.
 
Planktonmd said:
Why is a numb leg a bad thing compared to an excruciatingly painful leg? (Provided the surgeons are OK with it)
Click to expand...
Yeah I see your point but as Sevo mentioned with bundled payments and the like we will feel the push more and more to get them up and out asap. Those that adapt and move on will survive better than those that cling to the old "tried and true" ways of yesterday.
With that being said, I still do the SAB (+/- duramorph) with FNB and ant SNB. But my goal is complete or near complete resolution of the weakness by the next morning.
I think we are about to do a trial of the ACB VS our Standard here soon. The EXPAREL didn't show any benefits in our practice.
 
Noyac said:
Yeah I see your point but as Sevo mentioned with bundled payments and the like we will feel the push more and more to get them up and out asap. Those that adapt and move on will survive better than those that cling to the old "tried and true" ways of yesterday.
With that being said, I still do the SAB (+/- duramorph) with FNB and ant SNB. But my goal is complete or near complete resolution of the weakness by the next morning.
I think we are about to do a trial of the ACB VS our Standard here soon. The EXPAREL didn't show any benefits in our practice.
Click to expand...

Noy,

Are you going to continue doing the SNB along with an ACB in your trial? If so, I don't really see the point in switching from FNB. FNB is definitely superior in terms of analgesia, but at the expense of quad weakness. If you still make them non-ambulatory the first day via the SNB, then why sacrifice the extra pain relief from the FNB over the ACB??
 
SaltyDog said:
Noy,

Are you going to continue doing the SNB along with an ACB in your trial? If so, I don't really see the point in switching from FNB. FNB is definitely superior in terms of analgesia, but at the expense of quad weakness. If you still make them non-ambulatory the first day via the SNB, then why sacrifice the extra pain relief from the FNB over the ACB??
Click to expand...
Totally agree.
No I would stop doing both the FNB and SNB.
BUT I use 1.5% Mepiv for that block anyway. So it only last about 8 hrs. That's all they really need for the posterior knee pain and it allows the surgeon to assess for foot drop etc earlier.
 
Noyac said:
Totally agree.
No I would stop doing both the FNB and SNB.
BUT I use 1.5% Mepiv for that block anyway. So it only last about 8 hrs. That's all they really need for the posterior knee pain and it allows the surgeon to assess for foot drop etc earlier.
Click to expand...

Ok gotcha. Are you sure you really wanna look into ACB's though? I mean, that would require the use of U/S. 😉😀

It's gonna come down to how hard the orthodods are pushing for early ambulation. What you are doing now will give better pain scores but at the expense of getting the pts outta bed.
 
Adductor Canal blocks with Ipack work fine with most pain scores in the "2" range vs 0-1 with Femoral Block plus Ipack.

The real benefit of Exparel is not LIA but rather single shot ACBs and Ipacks where the duration of block is significantly prolonged. This means NO catheters and 48 hours+ duration of analgesia for the ACB. The Ipack block will likely be shorter but still over 24 hours.
 
Planktonmd said:
I am having trouble seeing the humor or the benefit of quoting this nurse...
Click to expand...


That "nurse" is the founder/owner of the militant CRNA website. In addition, he practices "independently" and claims equivalency with Anesthesiologists. Anyway, I wanted to point out that the Ipack block is an easy one to learn and doesn't take much skill.

One more thing I'm seeing more and more CRNAs refer to themselves as Doctors in all letters, e-mails, publications, etc. (CRNA DNP or CRNA PhD, DNP)
 
"Blocking the sciatic nerve, which is what provides inner variants the posterior of the knee, is dangerous, because it may cause foot drop and thus mask a surgically induced perineal nerve injury caused during surgery."

I'm sorry, but I don't understand why doing a sciatic (especially a short acting one with mepivicaine) will mask a perineal nerve injury. Maybe it will masking it for 8 hrs but after that it isn't masking ****. What exactly are you or the surgeon going to do differently in this time frame? So, you know about the foot drop earlier. What's the plan? What interventions are we gonna do? I don't get it.
I have been doing these blocks for 15 yrs and have never had an injury. Sure it can happen. But a meteor can hit earth tomorrow too.
 
BLADEMDA said:
That "nurse" is the founder/owner of the militant CRNA website. In addition, he practices "independently" and claims equivalency with Anesthesiologists. Anyway, I wanted to point out that the Ipack block is an easy one to learn and doesn't take much skill.

One more thing I'm seeing more and more CRNAs refer to themselves as Doctors in all letters, e-mails, publications, etc. (CRNA DNP or CRNA PhD, DNP)
Click to expand...
He can refer to himself with whatever letters or descriptions he likes, this does not change the fact that he learned the block from a YouTube video and has the audacity to write an article about it without giving credit to the original work done by MD anesthesiologists!
But yes, I agree with you, a chimpanzee can perform this block for a couple of bananas.
 
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