Infiltration Between Popliteal Artery and Capsule of the Knee Block to Augment Continuous Femoral Nerve Catheter for Adolescent Anterior Cruciate Ligament Reconstruction: A Case Series

A cadaveric study investigating the spread of injectate following an interspace between the popliteal artery and the capsule of the posterior knee block in a neonatal sample: a pilot study

The infiltration of the interspace between the popliteal artery and the capsule of the posterior knee (IPACK) block, is a novel ultrasound-guided technique used for postoperative pain management of the knee. The success of the block is attributed to the spread of injectate between the capsule of the knee and the popliteal artery. This novel technique is believed to target the articular branches of the tibial, common fibular (peroneal) and obturator nerves. However, the extent of the spread in a paediatric population is unknown. Therefore, this study aims to evaluate the spread of the IPACK block. Using ultrasound guidance, the IPACK block was replicated bilaterally in neonatal cadavers. Methylene blue dye (0.3 ml/kg) was injected proximally and distally. Subsequently, cadavers were dissected to determine the injectate spread. Proximal injections resulted in staining of some of the articular branches, while the distal injections resulted in staining of all four articular branches. Additional staining of the superior lateral and medial genicular nerves was noted irrespective of the technique. Overall, both injections resulted in posterior, anterolateral spread with limited medial spread. Results from this study reveal preservation of the main nerve trunks following the proximal technique, while the distal technique displayed greater staining of the articular branches. We believe that the block can be seen as a more holistic and viable alternative to lower limb blocks for the paediatric population, as it allows for a wider spread in the posterior and medial-lateral compartments of the knee.

Using the iPACK block to reduce chronic pain in a patient with knee osteoarthritis: A case report

Infiltration between the popliteal artery and capsule of the knee (iPACK) block is an emerging modality to control perioperative knee joint pain. This case report describes the successful control of chronic knee joint pain using iPACK block in a patient with knee osteoarthritis. We suggest that iPACK block could be applied in the fields of both pain medicine and perioperative analgesia. In addition, by placing the needle closely to the popliteal plexus, iPACK block could serve as an intervention for pain related to procedures such as radiofrequency ablation.

Ultrasound-Guided Local Anesthetic Infiltration Between the Popliteal Artery and the Capsule of the Posterior Knee (IPACK) Block for Primary Total Knee Arthroplasty: A Systematic Review of Randomized Controlled Trials

Posterior knee pain after total knee arthroplasty (TKA) is common despite multimodal analgesia and regional anesthesia use. This review included randomized controlled trials (RCTs) comparing analgesic outcomes after inclusion of local anesthetic infiltration between the popliteal artery and capsule of the knee (iPACK) block versus pathways without iPACK. Electronic databases (MEDLINE, Cochrane Library, Web of Science, Scopus) were searched from inception to 10/11/2020. Eligible studies evaluated iPACK use on primary outcomes: opioid consumption and pain scores with movement. Secondary outcomes included rest pain, patient satisfaction, length of stay (LOS), gait distance, knee range of motion (ROM), and complications. Bias and quality were appraised using the Cochrane Risk of Bias tool and Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) guidelines. Eight RCTs (777 patients) were included. iPACK block use demonstrated similar opioid consumption in the PACU (4/7 RCTs) and 24 hours after TKA (5/7 RCTs) compared to without iPACK (moderate-quality GRADE evidence). Additionally, iPACK block use demonstrated lower movement pain scores in PACU (3/5 RCTs) but similar or higher pain scores after 24 hours (5/7 RCTs; low-quality GRADE evidence). Studies consistently reported no difference in gait distance (4/4 RCTs) or complications (7/7 RCTs) between treatment arms (high-quality GRADE evidence), although differing effect estimates were observed with resting pain, satisfaction, LOS, and knee ROM. This review provides a foundation of knowledge on iPACK efficacy. While evidence does not currently support widespread inclusion of iPACK within enhanced recovery pathways for TKA, limitations suggest further study is warranted.

Trends in Pediatric Pain: Thinking Beyond Opioids

Trends in pediatric pain management are moving toward thinking beyond opioids. Regional anesthetic techniques, such as quadratus lumborum and erector spinae plane blocks, demonstrate efficacy and safety in pediatric populations. Extremity blocks with motor-sparing characteristics also are used. Adjuvants may be added to pediatric peripheral nerve blocks to increase duration of action and improve block efficacy. For medical management, pediatric pain management frequently uses nonopioid medications. These opioid-sparing medications and regional techniques are used to facilitate enhanced recovery after surgery in pediatric surgical patients. Virtual reality is a field where technology can aid in managing acute pain in pediatric patients.