|
Background
The concept of local infiltration analgesia (LIA) was first introduced by Kohan and Kerr to provide pain relief following total knee arthroplasty (TKA). Today, this simple, surgeon performed peri-articular injection under direct vision has become commonplace in clinical practice around the world. Up to 150 mL of local anesthetic solution (often ropivacaine 0.2%) containing a variety of adjuncts (epinephrine, NSAID, opioid, steroid) is injected during and at the end of TKA. The injection targets the anterior and posterior capsule of the knee, intercondylar area, collateral ligaments, tissue along the femur and tibia and the subcutaneous tissue.
The analgesic effectiveness of the LIA technique is undisputed and has been confirmed in multiple clinical studies. The only drawback of single shot LIA is limited duration of analgesia (hours) unless liposomal bupivacaine is injected which can extend analgesia to up to 72 hours. Indwelling LIA catheter is not commonly applied because of the fear of infection.
The iPACK block was first introduced by Dr. Sanjay Sinha. The acronym iPACK stands for infiltration between popliteal artery and capsule of the knee. The block is performed by anesthesiologists under ultrasound guidance to provide pain relief to the posterior aspect of the knee after TKA by blocking the articular branches of the tibial, common peroneal and obturator nerves in the popliteal region.
The iPACK block likely achieves a similar degree of analgesia as posterior capsule injection as part of LIA performed by the surgeon. However, the iPACK block has a potential technical advantage over LIA injection since it is ultrasound guided and the needle path aims to stay clear of the popliteal artery and the sciatic nerve. In contrast, surgeons are often reluctant to inject deep into the posterior capsule for the fear of accidental popliteal artery puncture and sciatic nerve block since these posterior anatomical structures are not visualized anterior to the posterior capsule.
At the time of writing, there is no randomized controlled trial to compare anesthesiologist performed iPACK with surgeon performed posterior capsule LIA with respect to analgesic effectiveness and duration.
- IPack iPack Retreat 3-Piece Wheeled Luggage Set, Blue, 3 Pc Set Kohl's on sale for $101.99 original price $249.99 $ 101.99 $249.99 The Next Best The 10 Best Blue Light-Blocking Glasses for 2020.
- IPack Contents handles the Contents portion of the loss and takes care of everything! Estimating, physical work, storage, billing and collection as well. We negotiate with the insurance carrier and get paid directly with no additional cost to the client.
IPack Builder v2 is the successor of the iPack Builder version 1. Version 1 was simple and didn’t allowed much more options,but that gave me an idea to develop much more advanced version and result. IPack Builder installers. With regard to icons, it is difficult to give an unambiguous preference for any of the programs. More recently, almost every developer posted their packages for IconPackager, later 7tsp replaced it, and today iPack is the favorite among all the others.
The iPACK block may be performed in the popliteal fossa about 1 finger breath above the patella (Figure 1, level 1) or more caudad at the level of the femoral condyle (Figure 1, level 2).
| Figure 1. Levels of iPACK injection. 1 = 1 finger breath above the patella. 2 = level of the femoral condyles. |
| Figure 2. Cross sectional view of the thigh just above the patella. |
| Figure 3. Cross sectional view of the thigh at the level of the femoral condyles. |
| Figure 4. Anatomical dissection showing articular branches of the tibial nerve, common peroneal nerve and obturator nerve to the posterior aspect of the knee. |
Scanning Technique
- Position the patient supine with the operative leg supported as shown below (Figure 5) and ultrasound position (Figure 6).
| Figure 5. Leg support position for iPACK block. |
- After skin and transducer preparation, a curved 2-5 MHz transducer is applied transverse on the medial thigh approximately 1 to 2 finger breaths above the patella (Figure 6).
| Figure 6. Transducer position over the medial aspect of the thigh approximately 1 finger breath above the patella. |
- The goal is to capture the best possible transverse and oblique view of the femoral shaft, the popliteal artery and the space posterior to the femoral shaft (Figure 7).
| Figure 7. Schematic diagram showing transducer position and scanned area. F = femoral shaft; PA = popliteal artery; SAR = sartorius muscle; SM = semi-membranosus muscle; VM = vastas medialis muscle |
- Optimize machine imaging capability by selecting the appropriate depth of field (usually within 7-8 cm), focus range and gain.
- Visualize the outline of the femoral shaft as a curved hyper echoic line.
- Also identify the pulsatile popliteal artery usually deep to the femoral shaft outline and a short distance posterior to the femur (Figure 8).
| Figure 8. Sonogram of popliteal region above the patella. F = femoral shaft; PA = popliteal artery |
Ipack Icons
Anatomical CorrelationCross sectional view of the thigh approximately 1-2 finger breaths above the patella, anatomical dissection vs. ultrasound (Figures 9 and 10).
| Figure 9. Cross section of the thigh showing anatomical structures immediately above the patella. F = femur; SAR = sartorius muscle; SM = semi-membranosus muscle; VM = vastus medialis muscle |
| Figure 10. Sonogram showing anatomical structures in the popliteal fossa at the same corresponding level. F = femur; PA = popliteal artery; SAR = sartorius muscle; SM = semi-membranosus muscle; VM = vastus medialis muscle |
| Figure 11. Cross section of the thigh showing anatomical structures at the level of the femoral condyle. FC = femoral condyle; PA = popliteal artery; SAR = sartorius muscle; SM = semi-membranosus muscle; SN = sciatic nerve |
| Figure 12. Sonogram showing anatomical structures in the popliteal fossa at the level of the femoral condyle. FC = femoral condyle; PA = popliteal artery; SAR = sartorius muscle; SM = semi-membranosus muscle |
Nerve Localization
- Perform a systematic anatomical survey from anterior to posterior and superficial to deep. The posterior capsule of the knee is located between the femoral shaft and the popliteal artery.
- With the transducer over the medial thigh (technique of Dr. Sanjay Sinha), identify the femoral shaft and the popliteal artery. The popliteal vein is often not seen. Note how far the artery is from the posterior aspect of the femur. This is the iPACK block approach at level 1 (1-2 finger breaths above the patella) (refer to Figure 1).
- Use Colour Doppler to localize the popliteal artery (Figure 13)
| Figure 13. Sonogram with Colour Doppler to visualize the popliteal artery. F = femoral shaft; Red area = popliteal artery |
- Move the transducer slightly more posterior to obtain a view of the femoral shaft near the edge of the screen. This slight scanning adjustment aims to identify a clear path for needle advancement. The goal is to avoid needle contact with the femoral shaft and unintentional popliteal artery puncture. Note that the desired needle insertion angle is often very steep (> 60o).
- Note that the tibial and common peroneal nerves are not usually seen.
Needle Insertion Approach
- Ultrasound guided iPACK block is considered an BASIC skill level block because this is a plane block.
- The In Plane (IP) approach is recommended to visualize the needle shaft and tip movement during needle advancement.
In plane approach antero-medial to postero-lateral approach at level 1 (1 - 2 finger breaths above the patella) according to the technique of Dr. Sinha.
- After skin and transducer preparation, a 8 cm 22 G echogenic block needle or a regular 22 G spinal needle is inserted into the medial thigh approximately 1 finger breath above the patella (Figure 14). Advance the needle often > 60 degree angle from the anterior end of the ultrasound transducer along its long axis in the postero-lateral direction.
| Figure 14. Picture showing leg, transducer and needle insertion positions. |
- Observe real time needle advancement posterior to the femur and stay clear of the popliteal artery.
- Aim to keep the needle immediately next to the femoral shaft at the start of needle advancement (Figure 15). The needle will invariably move posteriorly and laterally towards the popliteal artery as it is advanced deeper. Needle trajectory planning prior to actual needle insertion is therefore paramount.
- Stop needle advancement once the needle tip has reached the lateral wall of the popliteal artery.
| Figure 15. A schematic diagram showing the path and depth of needle advancement to reach the popliteal vessels. |
Out of Plane Approach
An out of plane approach is possible but clinical experience with this approach has not been reported.
Local Anesthetic Injection
- The goal is to deposit local anesthetic posterior to the femoral shaft in the interspace between the posterior capsule of the knee and the popliteal artery (Video 1).
- Note that injection too deep i.e., beyond the popliteal vessels may result in anesthetic spillage to branches of the sciatic nerve affecting the common peroneal nerve more commonly than the tibial nerve in association with the needle insertion approach described above.
- Inject a total of 10-15 mL local anesthetic incrementally as the needle is withdrawn slowly.
- The goal is to deposit a wall of local anesthetic in the posterior femoral interspace without affecting the sciatic nerve and its branches.
- In our centre, bupivacaine 0.25% is the anesthetic of choice but the optimal dose, concentration and volume of local anesthetic for iPACK block has not been determined. Neither has the optimal level of injection (above patella vs. at the femoral condyle level) been determined.
Selected References
- Kerr DR, Kohan L. Local infiltration analgesia: a technique for the control of acute postoperative pain following knee and hip surgery: a case study of 325 patients. Acta Orthop 2008;79(2):174-83.
- Reddy AVG, Jangale A, Reddy RC, Sagi M, Gaikwad A, Reddy A. To compare effect of combined block of adductor canal block (ACB) with IPACK (Interspace between the Popliteal Artery and the Capsule of the posterior Knee) and adductor canal block (ACB) alone on Total knee replacement in immediate postoperative rehabilitation. International Journal of Orthopaedics Sciences 2017;3 (2c):141-145.
- Sankineani, S.R., Reddy, A.R.C., Eachempati, K.K. et al. Comparison of adductor canal block and IPACK block (interspace between the popliteal artery and the capsule of the posterior knee) with adductor canal block alone after total knee arthroplasty: a prospective control trial on pain and knee function in immediate postoperative period. Eur J Orthop Surg Traumatol 2018.. https://doi.org/10.1007/s00590-018-2218-7
- Thobhani S, Scalercio L, Elliott CE, Nossaman BD, Thomas LC, Yuratich D, Bland K, Osteen K, Patterson ME. Novel Regional Techniques for Total Knee Arthroplasty Promote Reduced Hospital Length of Stay: An Analysis of 106 Patients. Ochsner J 2017;17 (3):233-238.
Logging in to IPaC using Login.gov
ECOS has partnered with DOI and login.gov to fulfill user authentication needs for all ECOS applications, including IPaC. This authentication service, provided by GSA, offers a single sign-on capability across several government websites and applications such as USAjobs.gov.
Login.gov supports authentication with a PIV card if you are a Federal user, and offers other two-factor authentication methods for non-federal users. This increases security by preventing hackers from compromising your account if they have your password only. In addition, login.gov improves single sign-on behavior so you don’t have to sign in multiple times when visiting different applications in ECOS. This integration satisfies enhanced Federal security requirements for multi-factor authentication.
How to log in:
- If you are new to login.gov, click ‘Create an account’ and set up your account. Login.gov has excellent instructions here. You must use the same email address that you use for IPaC today to link to your account information in IPaC. All Federal government employees with a government ID must associate their PIV cards with their login.gov account, as described in the login.gov instructions. Other users may choose another optional two-factor authentication method. You will need to create a login.gov account before logging in to IPaC.
Helpful tips:
- If you already have a login.gov account using the same email address you currently use for IPaC, you do not need to set up a new account. However, if you are an FWS user, you will need to associate your PIV card.
- If you have trouble setting up your account, you can contact the login.gov help desk at https://login.gov/contact/.
Known issues:
- PIV authentication does not work within the Firefox browser. Please use Chrome or Edge when logging in with your PIV.
- If you have multiple certificates associated with your PIV, you may get a time-out error. Select another certificate in the list; once you select the correct certificate you will be redirected to IPaC
Getting a Biological Assessment using Consultation Package Builder
IPaC’s Endangered Species Act (ESA) Review has a new step in the step-by-step consultation process--a feature called Consultation Package Builder (CPB) that was released in late December 2020. Because incomplete or poor information in consultation requests is a major factor in being unable to complete consultation in a timely manner, we designed CPB to address this need by:
- Helping you compile a complete Biological Assessment (BA);
- Assisting you in developing a good action area and documenting all potential effects and conservation actions associated with a proposed project;
- Leveraging the USFWS effect pathway data; and
- Providing a consistent, comprehensive information package that is ready to submit to the USFWS as a request for consultation.
Note: CPB replaces IPaC’s Impact Analysis feature.
The first release of CPB is a beta version. This means that substantive changes and additions are being made until the first official release of CPB in mid 2021. Most of the functionality is available now; however, some improvements are still under development.
Over time, you can expect helpful information for additional species and project types to be added into IPaC’s online consultation process.
Overview of CPB:
This new tool guides you through evaluating and documenting your project's potential effects on species protected by the Endangered Species Act.
For all species and designated or proposed critical habitat that are identified by IPaC, the Federal Action Agency is obligated to determine whether a project 'may affect' the species and critical habitat. If you determine that there will be 'no effect' to all species and critical habitat within the project action area, then a summary of your analysis can be saved for your records and you are finished.
If you identify that your project 'may affect' any species or critical habitat presented by IPaC, then consultation is required with the U.S. Fish and Wildlife Service and an analysis of the effects must be conducted. For some project types and species, IPaC helps you complete this analysis using data from the Service's internal effect pathway manager (EPM). Where available, IPaC presents EPM data as suggestions to consider during your analysis in CPB. CPB will then generate a biological assessment that you may submit as part of your consultation package to initiate consultation.
A consultation package contains documents that support your analysis of the project as it pertains to Section 7 of the Endangered Species Act, including the official species list, any determination key analyses, and a biological assessment (or similar environmental review document).
How it works:
After you request an official species list and evaluate any potential determination keys, IPaC guides you through the process of evaluating and documenting your project. Species that are not covered by determination keys should be evaluated through CPB. Here is an overview of the CPB process:
Describe the project site and activities:
- Describe the project site, including whether the species are present on the site
- Describe the project activities, including when and where they will take place
- For each activity, describe the impacts it may have on the land, air, and water (i.e., stressors)
For each anticipated stressor:
- Estimate the actual impact the stressor could have on the environment, considering any conservation measures you plan to include
- Draw the extent of the expected impact on a map, and confirm the action area
For each species and critical habitat:
Ipacket Login
- Evaluate whether the species will be exposed to the stressors, and if so, evaluate the potential impacts, taking into account the conservation measures used to limit the impacts
- Evaluate possible effects on individuals of the species that are a direct result of the project activities
- Make an effect determination