The study demonstrated the importance of monitoring accurate dosage and highlighted the need for additional long-term studies to better understand the role of cannabidiol in post-surgery pain management. 

The pilot study, conducted over four years, followed 36 patients who received cannabidiol as a part of their treatment following surgery. Previous surveys at HSS and other institutions have shown that many patients are using cannabidiol to self-medicate, creating challenges for providers. To ensure safety, only relatively healthy patients were enrolled due to the demanding and invasive nature of the surgery. 

“These patients experience significant pain after surgery and often require high doses of opioids,” said Alexandra Sideris, PhD, Director of the Pain Prevention Research Center at HSS and one of the co-authors of the study. “We approached this study knowing that if we were going to study a cannabis constituent to try to see if there is any benefit, we need to start with a population that could significantly benefit from adding on an additional medication. It is very painful to have both knees replaced.” 

According to internal HSS data, this specific patient population showed a clear need for better pain control. The study team performed a blinded study, dividing patients into three groups. Some patients did not receive any CBD; instead, they were given the placebo solution. The other two groups received 400 milligrams or 800 milligrams of CBD. Patients received their first dose right before they went into surgery. They then received three additional doses on the evenings of the subsequent postoperative days—for a total of four doses. The study team monitored how many opioids were required throughout the first 72 hours after surgery. 

“What we found after completing the study is that patients who were randomized or received the 400-milligram dosage actually had 30% lower opioid requirements compared to the group receiving 800 milligrams. We found a lower dose seemed to help but the higher does did not. This suggests the importance of finding the right balance when determining the appropriate dose,” said Dr. Sideris. “CBD appears to be promising, but we have to be very careful in terms of the doses we give to patients.” 

The study further showed that patients in the 400-milligram group reported lower pain scores at every time point measured, with nearly a two-point difference compared to the other groups. According to Dr. Sideris, the 800-milligram group had much higher opioid-related distress scores, which suggested the higher dose did not decrease opioid requirements but caused more side effects for patients. The side effects persisted for up to a week and included dizziness and fatigue. 

“Moving forward, we are planning to pursue more studies where we hope to focus on the lower dose of 400 milligrams and include a larger cohort of patients. Our data suggests that the side effects profile and the fact that we didn’t see any signal for decreased opioid needs or pain suggests that we probably don’t want to go into 800 milligrams for designing a larger study,” said Kethy M. Jules-Elysee, MD, an anesthesiologist at HSS and one of the co-authors of the study. 

Poster Details: 
Title: Effects of cannabidiol (CBD) oral solution in patients undergoing bilateral total knee arthroplasty: a randomized, controlled, parallel, triple blind, pilot study 

Co-authors: Chan W, Liu J, Baaklini L, Kirksey M, Illescas A, Waldman S, Jules-Elysee K, Sideris A 
William Chan1,3, Jiabin Liu1,2,3, Lila Baaklini1,2,3, Meghan Kirksey1,2,3, Alex Illescas1, Seth Waldman1,2, Kethy Jules-Elysee1,2, Alexandra Sideris1,2,3 

Study: Prevalence of cannabidiol use in patients undergoing sports medicine procedures on the knee, shoulder, or hip: A survey study 

Researchers set out to determine the prevalence of cannabidiol (CBD) use in patients scheduled to undergo a sports medicine procedure at HSS. “We know that managing post-operative pain with opioids carries risks, including addiction. A promising alternative gaining attention is cannabidiol, a non-intoxicating derivative of the cannabis plant that is federally legal in the United States,” said Alexandra Sideris, PhD, director of the Pain Prevention Research Center at HSS. The study was presented at the 50th Annual ASRA Meeting in Orlando, Florida on May 1. 

Reports from the National Survey on Drug Use and Health indicate that adults ages 18-35 are the most frequent self-reporters of cannabis use. “Our study aimed to shed light on the prevalence of self-medication with CBD in adults scheduled for elective sports medicine surgery on the knee, hip or shoulder, evaluating the effects in this patient population,” Dr. Sideris explained. 
Researchers emailed anonymous surveys to 470 patients between September 2024 and December 2024. Out of 159 respondents, 39% of patients reported having tried CBD. Approximately one-third indicated that they used CBD on an as-needed basis, primarily for pain or to help them sleep. Most patients used gummies, and 44% purchased them from a dispensary. One-third of the respondents indicated that CBD was either moderately or very helpful. 

“At HSS, ongoing data collection and analysis will further elucidate the perceived efficacy of cannabidiol and the potential for changes to prescription medication use with the incorporation of CBD,” Dr. Sideris noted. 

With respect to the President’s Choice award, she commented, “It is an honor to have one of the top professional organizations in the field of regional anesthesia and pain medicine highlight the collaborative work of our department's Pain Prevention Research Center. The award reflects our dedication to innovations in patient care and underscores the greater scientific community's acknowledgements of our efforts.” 

Study: Opioid Consumption During Hospitalization Across Manual, Computer- and Robotic-Assisted Total Hip Replacement

In the second study to win a President’s Choice award, HSS researchers found that patients who had robotic-assisted total hip replacement (THR) surgery needed less opioid medication during hospitalization compared to patients who had computer-assisted or manual THR. The research was presented at the ASRA meeting on May 2. 

“Effective pain management while limiting opioid consumption following total hip replacement is imperative, as it facilitates immediate postoperative function and leads to better long-term outcomes,” said Periklis Giannakis, MD, a research fellow at HSS. “While patient characteristics are important factors associated with pain control, surgical technique is also relevant. We aimed to determine if the way hip replacement was performed had an effect on the need for opioid medication after surgery.” 
Analyzing a multi-institutional database with almost 100,000 hip replacement cases, Dr. Giannakis and colleagues found that robotic-assisted hip replacement was associated with the lowest total opioid consumption during hospitalization. He noted that while the exact mechanism is unknown, reduced soft tissue trauma and a more precise robotic-assisted surgery may contribute to less acute inflammation and less pain immediately after the procedure. 

Regarding his President’s Choice award, Dr. Giannakis commented, “Receiving President’s Choice recognition is a great honor for me and a testament to the collaboration and important research that we conduct at HSS.” He notes that future collaborative studies between the Department of Anesthesiology, the Pain Prevention Research Center and the Adult Reconstruction and Joint Replacement Service at HSS will seek to obtain more specific data, such as which robotic- and computer-assisted systems were used, with the ultimate goal of optimizing postoperative pain control. 

References: 
Prevalence of cannabidiol use in patients undergoing sports medicine procedures on the knee, shoulder, or hip: A survey study 
Authors: Sophia Madjarova BA, Arjun Khorana BS, William Chan MEng, Answorth Allen MD, Riley Williams MD, Benedict Nwachukwu MD, MBA, Alexandra Sideris PhD. 
Opioid Consumption During Hospitalization Across Manual, Computer- and Robotic-Assisted Total Hip Arthroplasty 
Authors: Periklis Giannakis, MD, Juliet E. Rowe, MPH, Lisa Reisinger, MD, Alex Illescas, MPH, Alexandra Sideris, PhD, Crispiana Cozowicz, MD, Junying Wang, MPH, Sophia T. Zhuang, Jiabin Liu, MD, PHD, Lazaros Poultsides, MD, PHD, Robert G. Marx, MD, Alejandro Gonzalez Della Valle, MD, Jashvant Poeran, MD, PhD, Stavros G. Memtsoudis, MD, PhD, MBA. 
 

“It is an honor to have one of the top professional organizations in the field of regional anesthesia and pain medicine highlight the collaborative work of our department's Pain Prevention Research Center,” said Alexandra Sideris, PhD, director of the Pain Prevention Research Center at HSS. “The award reflects our dedication to innovations in patient care and underscores the greater scientific community's acknowledgement of our efforts.” 

More than one million people undergo knee replacement surgery each year in the United States, and those numbers continue to rise, Dr. Sideris notes. “There is a need to better understand patients’ individual pain trajectories, and one of the most exciting approaches is to leverage artificial intelligence. With our huge patient database at HSS, machine learning can analyze factors such as age, gender, BMI, and presurgical pain levels to predict which patients are at greater risk of severe pain after surgery,” she said. Armed with this information, the care team can tailor personalized pain management plans to meet patients’ needs. 

The HSS researchers had several goals: utilize machine learning to identify pain archetypes following total knee replacement; determine important features for predicting pain outcomes; and classify patients at risk of severe pain in the immediate postoperative period. The retrospective study included 17,200 patients who had total knee replacements at HSS from April 1, 2021, to October 31, 2024. 

“Using unsupervised machine learning, we identified two distinct pain archetypes in patients who underwent total knee replacement, which corresponded to those who experienced severe, difficult to control pain after surgery and those whose pain was relatively well controlled,” explained Justin Chew, MD, PhD, a clinical fellow at HSS who presented the study at the ASRA meeting on May 1. “We then utilized supervised machine learning to determine the most significant predictive factors for severe pain. In our study, risk factors included younger age, greater physical/mental impairment, higher BMI, and preoperative opioid or gabapentinoid use.” 

Dr. Sideris notes that ongoing and future studies at HSS will continue to leverage AI with the goal of improving patient outcomes. While the award-winning study focused on the immediate postoperative period, she said additional studies will follow patients’ pain trajectory and recovery over longer periods of time to determine which strategies doctors can employ before surgery, intraoperatively and in the immediate postoperative period to manage pain in high-risk patients. 

Reference: 
Classification and stratification of patient pain archetypes following total knee arthroplasty: a machine learning approach 
Justin Chew, MD, PhD, Junying Wang, Alexandra Sideris, PhD, Victoria Xu, Daniel Maalouf, MD, MPH, Stavros Memtsoudis, MD, PhD, MBA, Jashvant Poeran, MD, PhD, Jiabin Liu, MD, PhD. 

“The ASRA research awards recognize HSS’s tireless pursuit of patient safety and innovative treatments in pain management,” said Stavros Memtsoudis, MD, PhD, MBA, Chief of Anesthesiology, Critical Care and Pain Management at HSS and principal investigator of one of the award-winning studies, “Preoperative GLP-1 Agonist Use is Not Associated with Perioperative Aspiration or Pneumonia: A National Observational Study.” “These accolades validate our leadership in research, reinforcing our efforts to enhance safety standards and improve patient outcomes in pain management through evidence-based practices and multidisciplinary collaborations.”

The ASRA Research Committee selects three out of the top 10 highest-scoring scientific abstracts that have met all ASRA Pain Medicine abstract submission requirements and ASRA Pain Medicine membership to be Best of Meeting Abstract winners.

The Patient Safety Award was created in the spirit of Alice Romie to recognize exemplary patient safety work. Alice was an advocate for patient safety who contributed to standardizing medication safety and educating peers about this issue and who passed away from breast cancer in May 2021.

The two Best of Meeting award-winning studies were titled “Effects of Perioperative Dronabinol Use in Total Knee Arthroplasty” and “Preoperative GLP-1 Agonist Use is Not Associated with Perioperative Aspiration or Pneumonia: A National Observational Study.” 

Dronabinol is a synthetic tetrahydrocannabinol (THC) agent that is FDA-approved to treat nausea and vomiting from chemotherapy and to stimulate appetite in patients with HIV or AIDS. Prior studies suggest that cannabinoids may also have pain-relieving properties. While cannabis contains both THC and cannabidiol (CBD), the plant is federally illegal, so it is difficult to study its effects in a hospital setting. As a legal alternative, researchers sought to examine whether 5mg of perioperative dronabinol twice a day could reduce pain and opioid consumption 24 to 48 hours after total knee arthroplasty compared with placebo.

While there were no statistically significant differences in opioid consumption compared with placebo, this study adds to the literature on the effects of THC (in the form of dronabinol) in the perioperative period. Further research examining different dosing regimens of dronabinol for acute pain is warranted.

“In an attempt to decrease perioperative use of opioids in view of the opioid epidemic, it has become even more important to study drugs such as the cannabinoids known to have potential analgesic properties,” said HSS anesthesiologist and lead study author Kethy Jules-Elysee, MD. “Dronabinol was not effective in decreasing pain or opioid consumption in this study with such a rigorous design. However, it was well tolerated. Future studies looking at patients with a history of cannabis use or chronic opioid use should be done, and different dosages of dronabinol should be explored.” Researchers at HSS are also conducting a pilot study examining CBD (Epidiolex) in bilateral total knee replacements.

In the study “Preoperative GLP-1 Agonist Use is Not Associated with Perioperative Aspiration or Pneumonia,” researchers examined whether glucagon-like peptide-1 (GLP-1) medications might affect aspiration or pneumonia risk in patients undergoing surgery. The medications mimic hormones produced in the gut that reduce appetite and cause the body to release insulin, and they are commonly prescribed for diabetes management or weight loss. 

“The increased prescribing of these medications in recent years is likely to result in an increase in patients scheduled for surgery that are on these medications,” said Dr. Memtsoudis. “In a cohort (using MarketScan commercial claims 2017 to 2021 data) of lower extremity joint replacement, hysterectomy, appendectomy and cholecystectomy surgery, preoperative GLP-1 use appears not to be associated with odds of perioperative aspiration or pneumonia. This information may help guide clinical decision-making regarding the use of GLP-1 medications in the preoperative period. However, further research and consideration of broader implications would be necessary before implementing any policy changes.”

In the study that won the 2024 ASRA Patient Safety Award, “Is Spinal Anesthesia Safe in Patients with a History of Guillain-Barré Syndrome Undergoing Orthopedic Surgery?” researchers examined whether regional anesthesia, which has many safety and pain management benefits compared with general anesthesia, is safe for patients with Guillain-Barré syndrome. 

“Guillain-Barré Syndrome (GBS) is a rare autoimmune disorder which results in acute demyelination of the peripheral nervous system, typically after some sort of symptomatic infection,” explained David Lee, MD, an anesthesiologist at HSS and lead study author. “As such, the issue of whether to perform a neuraxial anesthetic technique in these patients has remained a controversial topic due to fears that a spinal may predispose this patient population to worsening neurological symptoms or result in a recurrence of GBS. Because there are many positive benefits to performing a neuraxial anesthetic technique versus general anesthesia, such as decreased mortality, decreased postoperative nausea and vomiting (PONV), and reduced incidence of deep-vein thrombosis, we sought to examine our experience with GBS patients undergoing lower extremity orthopedic procedures over the past 10 years using EPIC to see whether there were any differences in recovery or neurological outcome after administration of a spinal anesthetic.”

In this observational retrospective chart review of 103 patients with a documented history of GBS who underwent some type of lower extremity orthopedic procedure at HSS from 2014 to 2023, 79 patients received a spinal anesthetic and 18 received a general anesthetic. The researchers found no appreciable difference between the groups in postoperative neurological outcomes, length of stay in the post-anesthesia care unit, or length of hospital stay. Similarly, there were also no appreciable differences between the groups in terms of time to achieving physical therapy milestones or incidence of postoperative nausea and vomiting.   

“Because the incidence of GBS is rare (the CDC estimates 3,000 to 6,000 cases per year), the total volume of cases in this study represents a small fraction of the 41,500-plus orthopedic surgeries performed annually at HSS, 85 percent of which are done with a regional anesthetic technique,” said Dr. Lee. “These findings should give both patients and clinicians some measure of assurance that neuraxial anesthetic techniques can be safely performed in someone who has had prior GBS. Larger longitudinal studies would be beneficial to corroborate these findings, so new policies and ASRA guidelines can be established with confidence with regards to the use of neuraxial anesthesia in patients with a prior history of GBS.”

“HSS's commitment to researching new techniques for better outcomes is evident in its dedication to advancing patient care through rigorous scientific inquiry and clinical innovation,” said Dr. Memtsoudis. “By exploring emerging technologies and refining procedural techniques, HSS remains at the forefront of anesthesia administration, pain management, and critical care, ensuring that patients receive the highest standards of care.”

In addition to these three award-winning studies, HSS also presented 20 abstracts and either lectured at or moderated more than 25 sessions, workshops, problem-based learning discussions, poster sessions, and special interest group meetings at this year’s ASRA conference.

References

1. Thor P, Perlstein M, Illescas A, Lauzadis J, Sheetz M, Tailor M, Puglisi A, Popovic M, Oxendine J, Lin Y, Kirksey M, YaDeau J, Kumar K, Baaklini L, Liu J, Cheng S, Mayman D, Jerabek S, Westrich G, Cushner F, Cross M, Sculco P, Sculco T, Ast M, Gonzalez-Della Valle A, Sideris A, Jules-Elysee KM. “Effects of Perioperative Dronabinol Use in Total Knee Arthroplasty.” Presented at: 49th Annual Regional Anesthesiology and Acute Pain Medicine Meeting of the American Society of Regional Anesthesia and Pain Medicine (ASRA), March 21-23, 2024; San Diego, CA.

2. Jashvant Poeran, Yhan Colon Iban, Haoyan Zhong, Alex Illescas, Crispiana Cozowicz, Lisa Reisinger, Jiabin Liu, Stavros Memtsoudis. “Preoperative GLP-1 Agonist Use is Not Associated with Perioperative Aspiration or Pneumonia: A National Observational Study.” Presented at: 49th Annual Regional Anesthesiology and Acute Pain Medicine Meeting of the American Society of Regional Anesthesia and Pain Medicine (ASRA), March 21-23, 2024; San Diego, CA.

3. Tra BM, Haidar J, Lauzadis, J, Illescas A, Lee D. “Is Spinal Anesthesia Safe in Patients with a History of Guillain-Barré Syndrome Undergoing Orthopedic Surgery?” Presented at: 49th Annual Regional Anesthesiology and Acute Pain Medicine Meeting of the American Society of Regional Anesthesia and Pain Medicine (ASRA), March 21-23, 2024; San Diego, CA.

“The feeling of fear is very natural, and every single one of us knows that feeling,” said Stephanie Cheng, MD, DABMA, FAAMA. Dr. Cheng is an anesthesiologist at HSS and developed HSS’s protocols for using acupuncture in the operating room. “For some people, that fear can become irrational and develop into PTSD. Although exact numbers are unknown, reported estimates for the incidence of PTSD in the United States are approximately 6%, with women having twice the rate of men.

“For patients with nosocomephobia, it can make getting care in the hospital setting very hard,” she continues. “We don’t even know how many of these ‘unseen patients’ are out there because they just don’t come to the hospital.”

Current treatments for nosocomephobia include techniques such as cognitive behavioral therapy, exposure therapy, hypnotherapy, and medications.

“It’s worth noting that acupuncture isn’t even listed as a treatment on many patient information websites, despite it being well researched in PTSD patient populations,” Dr. Cheng said. “While acupuncture has been well studied with outpatient PTSD patients, specifically in the military, using it in the operating room is almost unheard of. Our study shows that offering acupuncture to patients is something that can help them feel more in control of the situation and get through surgery successfully.”

For these case studies, two patients were interviewed about their nosocomephobia and their prior hospital experiences. Using Dedoose software, six reviewers coded the interview transcripts line-by-line. The reviewers labeled meaningful words, phrases, and sentences, and created more than 600 codes. The reviewers grouped similar codes to identify themes, and then conducted a thematic analysis to generalize the study’s themes and construct its theoretical framework.

This analysis demonstrated how nosocomephobia affected patients’ perceptions of surgery and helped identify their individual fears. The researchers diagrammed the thought process of the patients to show how they considered whether they felt comfortable enough to get surgery. The appraisal process included three steps: experiencing the stressor (surgery), how they would be able to cope (acupuncture), and their mental state about whether they believed they could go through with the surgery (reappraisal).

In the case of these two patients with nosocomephopbia, acupuncture was a safe, non-invasive way for them to manage their preoperative anxiety and undergo elective surgery.

“Our research is based on a limited number of cases and makes it difficult to draw any major conclusions. We need to study more patients who have a major fear of hospitals and who need surgery and see whether offering acupuncture intraoperatively can successfully get those patients through surgery,” Dr. Cheng explained. “We also need to make more patients and doctors aware that this modality is available, and that it can be really helpful to patients suffering with PTSD.”

“If the addition of intraoperative acupuncture can prove to be helpful for patients who have a fear of hospitals, then we can really change the quality of life of a segment of the population that has historically been difficult to treat. The unseen patient can finally be seen,” Dr. Cheng concluded.

Reference

1. Pa Thor PhD, Andrew Moreno MS, MD, Haoyan Zhong MS, Miriam Sheetz BS, Marko Popovic BS, Sabrina M. Strickland MD, Michael P. Ast MD, Stephanie I. Cheng MD, DABMA, FAAMA. “A Qualitative Analysis of Intraoperative Acupuncture for Nosocomephobia: The Unseen Patient.” Presented at: 6th World Congress on Regional Anaesthesia & Pain Medicine, September 6-9, 2023, Paris, France.

“Usually for hip arthroscopy, the anesthesiologist performs a type of neuraxial block; in this case, a femoral nerve block or fascia iliaca block,” said Lisa Reisinger, MD, a research fellow at HSS and one of the authors of the study. “With these blocks, there is an adverse effect of quadriceps weakness leading to elevated fall risk and prolonged hospital stay.”

“PENG and LFCN are both motor-sparing blocks, but neither provide adequate pain relief for hip arthroscopy on their own,” Dr. Reisinger explained. “The purpose of this study was to evaluate whether these nerve blocks performed at the same time would lead to adequate analgesia with opioid-sparing effects and earlier discharge. While these are two commonly used techniques, it is not yet common to use them together for hip arthroscopy.”

Twenty-six patients who received only the PENG block and 86 patients who received both the PENG and LFCN blocks were matched to a control group of 112 patients who received only a neuraxial block using propensity score matching (1:1) and a caliper of 0.2, to match patients by American Society of Anesthesiologists classification, gender, and age.

The primary examined outcome was average opioid consumption in the PACU. Secondary outcomes included maximum numerical rating scale (NRS) pain score, intravenous (IV) rescue analgesia, and PACU readiness for discharge times.

The combination of a PENG block and LFCN block showed a significant reduction in average opioid consumption (more than 40% less) and earlier PACU discharge times (more than 1.7 hours earlier) compared with neuraxial alone.

There were also significantly lower severe pain scores in the PENG/LFCN group than the neuraxial alone group, which was demonstrated with the PENG/LFCN group using significantly less IV rescue analgesia and having lower maximum NRS pain scores. The PENG block alone did not demonstrate a significant pain relief benefit compared with the control group, although it did decrease the amount of time to discharge.

These results demonstrate that using both the PENG and LFCN nerve blocks may provide the best pain relief, reduce opioid use, and reduce discharge times compared with PENG block alone or neuraxial analgesia alone.

“Patients are looking for alternatives to minimize narcotic use after surgery,” said David Kim, MD, an anesthesiologist at HSS and lead author of the study. “This study offers an opioid-sparing alternative for ambulatory hip arthroscopy.”

“The next stage of research should be focusing on whether PENG/LFCN combination provides any longer-term outcome benefits to our patients, such as functional outcomes, post-discharge opioid consumption, etc.,” said Jiabin Liu, MD, an anesthesiologist and one of the authors of the study.

“Most blocks have a duration of 24 to 48 hours,” Dr. Kim added. “The next focus should be on methods for lengthening the duration beyond that.”

Reference

1. Lisa Reisinger, MD, Genewoo Hong, MD, JD, Edward Lin, MD, Sang Jo Kim, MD, Jonathan Beathe, MD, Douglas Wetmore, MD, Jiabin Liu, MD, David H Kim, MD. “Pericapsular nerve group block combined with a lateral femoral cutaneous nerve block decreases opioid consumption after hip arthroscopy: a retrospective cohort study.” Presented at: 6th World Congress on Regional Anaesthesia & Pain Medicine, September 6-9, 2023, Paris, France.

“This new block provides excellent anesthesia and analgesia to foot and ankle surgeries and preserves motor function of the ankle joint. The results are very promising,” said Enrique A. Goytizolo, MD, an anesthesiologist at HSS and senior author of the study. “New protocols of early rehabilitation of foot surgeries can be instituted, since patients have no pain with movement of the foot.”

An ultrasound-guided popliteal block is the current standard anesthetic technique for foot and ankle surgeries, but the study findings show that using an ultrasound-guided mid-calf block could enable earlier rehabilitation protocols and an overall faster recovery from surgery.

A popliteal block numbs the sciatic nerve at the level of the popliteal fossa, which is a diamond-shaped space behind the knee joint. A mid-calf block is placed farther down the leg, between the popliteal fossa and the ankle, and numbs the posterior tibial nerve, superficial and deep peroneal nerves, sural, and saphenous nerves. A mid-calf block provides prolonged analgesia for any foot or ankle surgery while preserving motor function of the ankle joint.

Twenty patients who were scheduled to receive foot or ankle surgery at HSS were recruited for the study. The procedures included total ankle replacement, ankle arthroscopy, bunionectomy, cheilectomy, and Achilles tendon repair. Participants were assessed in the post-anesthesia care unit (PACU) and again before discharge to record the time when the mid-calf block ended, presence of paresthesia, and any other side effects. On postoperative days 1, 2, and 7, participants were asked about their pain on a numerical rating score (NRS), their medication use, and other symptoms.

The researchers found that the median duration of analgesia from the mid-calf block was 18.2 hours, with an interquartile range of 4.5-24.0 hours. All 20 patients were able to flex their toes in the PACU.

The average pain score in the PACU was 0.8 +/- 2.1 at rest, and 1.1 +/- 2.3 with movement. Three participants were excluded for sensitivity analysis because they received additional surgery in surgical areas not covered by the mid-calf block. Among the 17 patients in the sensitivity analysis group, these scores were both 0.3 +/- 1.2 at rest and with movement.

“The mid-calf block provides reliable, consistent, and excellent anesthesia and analgesia for foot and ankle surgeries,” said Dr. Goytizolo. “Follow-up research and patient treatments following this study should include a fast-track rehabilitation program for patients who have total ankle replacement surgeries with a mid-calf block.”

The findings of this study will also inform future randomized control trials on the mid-calf block.

Reference

1. Marko Popovic BS, Alex Illescas MPH, Pa Thor PhD, Jacques YaDeau MD PhD, Constantine Demetracopoulos MD, Scott Ellis MD, Vincent LaSala MD, Matthew Roberts MD, Anne H. Johnson MD, Mark Drakos MD, Enrique Goytizolo MD. “Mid-Calf Block for foot and ankle surgery: A pilot study.” Presented at: 48th Annual Regional Anesthesiology and Acute Pain Medicine Meeting of the American Society of Regional Anesthesia and Pain Medicine (ASRA), April 20-22, 2023; Hollywood, FL.

“The utility of interventions in a general population of patients might be difficult to show, but might differ by subgroups, with certain patients deriving benefit when others do not,” said Stavros G. Memtsoudis, MD, PhD, MBA, an anesthesiologist at HSS and lead author of the study. “In this study, we tried to identify which subgroups might benefit most from peripheral nerve blocks in terms of a reduction in complications after joint arthroplasty.”

These findings demonstrate that comorbidities may be a factor with a greater effect on complication risk than other factors, such as age, and that peripheral nerve blocks alone may not be sufficient to consistently influence outcomes in patients with comorbidities.

These findings may also demonstrate that there may be a specific optimal baseline patient population for whom peripheral nerve blocks have the greatest impact on improving surgical outcomes: patients who are older but do not have many comorbidities. This study could help clinicians determine which surgical patients may benefit most from peripheral nerve blocks and which candidates may need additional measures to improve their outcomes.

Many total joint arthroplasty (TJA) patients are at risk for poorly controlled pain and complications. The number of these surgeries performed increases each year, underscoring the importance of finding solutions. To find out how uniformly peripheral nerve blocks can improve perioperative outcomes and pain relief in TJA patients, the researchers conducted a population-based analysis using data from TJA surgeries in the United States from January 2006 to December 2019.

Patients were divided into nine groups based on age and number of comorbidities. Age was broken down as follows: Young (Y) = younger than 65 years; Middle (M) = 65 to 75 years; and Old (O) = older than 75 years. Comorbidities were categorized as: no pre-existing comorbidity (Group 1); 1 or 2 comorbidities (Group 2); and 3 or more comorbidities (Group 3). This led to a breakdown of nine groups total: Y1, Y2, Y3, M1, M2, M3, O1, O2, and O3.

The sample included more than 2.8 million TJA cases performed in 887 hospitals. Of those, 15.5% received a peripheral nerve block. The overall rate of peripheral nerve blocks increased from 9.5% in 2006 to 18.9% in 2019. Peripheral nerve blocks were used least often in young patients with more than 3 comorbidities (13.9%) and used most often in middle-aged patients with no comorbidities (16.3%). Peripheral nerve blocks were associated with a significant reduction in the odds of respiratory complication, acute renal failure, delirium, ICU admission, high opioid consumption during hospitalization, and prolonged length of stay.

The results showed reduced odds of respiratory complications for the O1 and Y2 groups, reduced odds of acute renal failure in the Y1, O1, and M2 groups, and reduced odds of delirium in O1. The risk for ICU admission was reduced in those who received peripheral nerve blocks in all ages with no comorbidities, as well as in the Y2 and O2 groups, compared with those who did not receive a peripheral nerve block. Peripheral nerve blocks also reduced the odds of a prolonged length of stay in the Y1, M1, Y2, M2, and Y3 groups. Odds of high opioid use in patients who received a peripheral nerve block versus no peripheral nerve block were significantly reduced in all groups except for Y3 and O3.

“While peripheral nerve blocks might have the advantage of providing superior pain control versus systemic modalities as well as reducing opioid consumption, a reduction in complications might be expected in those without comorbidities,” Dr. Memtsoudis said. “However, given that peripheral nerve blocks still provide better pain control and reduce opioid use, all patients should be considered for peripheral nerve blocks.”

“Older patients without major comorbidities might represent a subgroup in which the beneficial effects of peripheral nerve blocks are most likely to be expected,” he noted. “This might be the case because major comorbidities are a bigger determinant of complications, with peripheral nerve blocks being less likely to be able to exert a substantial effect.”

Future research should include further examination of the benefits of peripheral nerve blocks. “Many questions remain unanswered, including quantification of attributable risk reduction of peripheral nerve blocks and which peripheral nerve blocks provide the biggest effect,” Dr. Memtsoudis concluded.

Reference

1. Haoyan Zhong MPA, Marko Popovic BS, Jashvant Poeran MD PhD, Crispiana Cozowicz MD, Alex Illescas MPH, Jiabin Liu MD PhD, Stavros G Memtsoudis MD PhD MBA FCCP. “Does the impact of peripheral nerve blocks vary by age and comorbidity subgroups? A nationwide population based study.” Presented at: 48th Annual Regional Anesthesiology and Acute Pain Medicine Meeting of the American Society of Regional Anesthesia and Pain Medicine (ASRA), April 20-22, 2023; Hollywood, FL.