Quadratus Lumborum Block for Analgesia Following Hip Arthroscopy

The number of hip arthroscopy cases has surged with over a 200% increased experienced between
2007 and 2011 [1-3]. This increased number of cases is due to both improved techniques and an
increased number of indications [4-5]. As with most newer operative techniques, the optimal
method of perioperative pain control is still emerging and past publications indicate that
the majority of patients experience moderate to severe pain postoperative pain [6-8]. In the
wake of a national opioid epidemic, consistent and reliable implementation of non-opioid
analgesic strategies is exceedingly important and regional anesthesia often plays a key role
in postoperative pain management.

Although quadratus lumborum blocks were first described in 2007 as an truncal block, numerous
publications have recently highlighted its effectiveness as an analgesic technique for hip
fracture and hip arthroplasty [9-15] and possibly the ideal regional technique for hip
arthroscopy [16]. Unfortunately, prospective randomized studies are lacking. This prospective
study would randomize patient to receive or not receive a quadratus plane block prior to
surgery. The primary end point would be opioid consumption in the postoperative anesthesia
care unit. Our hypothesis is that quadratus lumborum blocks will decrease postoperative
opioid consumption.

The quadratus lumborum blocks is fascial plane block. Originally described for abdominal
surgery, numerous case reports and editorial publications have highlighted the effectiveness
of quadratus lumborum blocks as an analgesic technique for hip fracture and hip arthroplasty
[1-9] and possibly the ideal regional technique for hip arthroscopy [16]. Unfortunately,
prospective randomized studies are lacking.

The quadratus lumborum block is performed by injecting local anesthetic deep to the
transversus abdominus abdominus apnoneurosis and superficial to the fascia transversalis with
direct ultrasound guidance. After completing consent, placing monitors and providing mild
sedation, the patient is positioned laterally and the muscular anatomy (external oblique,
internal oblique, transverse abdominis, quadratus lumborum and latissimus dorsi muscles)
identified. After placing a subcutaneous skin wheel with lidiocaine, a blunt regional
anesthesia needle is inserted using in-plane ultrasound guidance. Local anesthetic is
deposited incrementally with frequent aspiration in the anterolateral border of the quadratus
lumborum muscle at the junction of the transversalis fascia, outside the anterior layer of
the thoracolumbar fascia and superficial to the fascia transversalis.

Risks of the quadratus lumborum block are similar to most truncal blocks and include
infection, bleeding, bowel perforation or local anesthethetic toxicity (LAST). Infection risk
is minimized by utilizing appropriate antiseptic and sterile technique as is standard for any
regional procedure. Risk of a retroperitoneal hematoma is increased with the deep (QL3)
approach to the quadratus lumborum block because of its transmuscular approach and likelihood
of abdominal branches of lumbar arteries in the path of the needle. For this reason, this
(QL3) approach to the quadratus lumborum block will not be used for this study. The risk of
LAST is a risk with any regional procedure and is minimized by frequent aspiration,
incremental local anesthetic injection and vital signs monitoring throughout.

The quadratus lumborum block is already a block utilized daily at MUSC for a variety of
surgical procedures to decrease postoperative pain. Additionally, the block has been offered
at MUSC to patients with uncontrolled postoperative pain following hip arthroscopy with
excellent resulting analgesia. Unfortunately, whether a patient undergoing hip arthroscopy at
MUSC is offered a quadratus lumborum block for postoperative pain is currently highly
provider dependent. We hypothesize that preoperative quadratus lumborum blocks will reduce
opioid consumption following elective hip arthroscopy.

Sample size was determined using G*Power version 3.1.9.2 software. Using preliminary data, we
estimate that we will need 19 subjects in each group (N=38) to have sufficient power (80%) at
alpha=0.05 to test the hypothesis of a 30% decrease in IV ME opioid consumption in patients
having a QL block vs. those with no block. Accounting for a possible 20% withdrawal, we
anticipate the need to enroll 46 total subjects.

Patients will be invited to participate by a study team member that is IRB approved, CITI
certified and trained on the protocol. Eligibility will be determined by screening the
operating room schedule for patients undergoing hip arthroscopy.

Patients will be enrolled on the day of surgery in the preoperative holding area. After
discussion with surgeons, patients will be educated on the role of regional anesthesia in
postoperative analgesia and a quadratus lumborum block described.

During pre-operative appointments the surgeons will notify potential participants that they
may be invited to participate in this study on the day of surgery. The surgeon will provide
potential participants with the consent document to review prior to day of surgery. After
discussion in the preoperative holding area regarding risks and benefits of the study and the
quadratus lumborum block, patients will be consented if they choose to participate. Consent
will be obtained from patient by an IRB approved CITI certified study team member that has
been trained on the protocol. Copies of all documents will be provided to the patients. Once
patients are consented, they will be assigned a two digit enrollment number. Prior to patient
enrollment, randomization will done by a statistician and randomized group (no block (current
practice) or quadratus lumborum block) assigned based on the patient enrollment number.

This prospective, single blinded clinical trial will randomize patient to receive or not
receive a preoperative quadratus lumborum block prior to elective hip arthroscopy. The
consent form will be distributed to patients preoperatively in the surgeon's office. On the
day of surgery in the preoperative holding area, patient undergoing elective hip arthroscopy
would be informed about the trial and the block with both the risks and benefits. If they are
interested in participating, informed consent would then be completed.

Once patients have signed an informed consent, they would be assigned a two-digit
identification number. Numbers would be assigned sequentially with the first enrolled patient
receiving "01," the second patient receiving "02," and the last patient receiving number
"38." Randomization will be created prior to the study starting by a statistician with half
of the research subject number being assigned to receive a nerve block and the other half
assigned to not receive a block, which is our current standard of care. The regional
anesthesia team will open the envelope labeled with the patient's assigned number to reveal
the randomization.

Following informed consent, all patients will be positioned, prepped and sedated for a
quadratus lumborum block in the preoperative holding area to blind the patient, surgeon,
intraoperative anesthesia team and data collectors. The patient will be positioned in the
lateral decubitus position with the operative side up and pulse oximetry and blood pressure
cuff placed for monitoring. As part of routine care, the patient will receive sedation for
their comfort. The relevant anatomy will then be identified using an ultrasound. The skin
will be cleaned with chlorhexidine. If the subject has been randomized to the "no block"
group, a subcutaneous saline skin wheel will be placed and the procedure would end at this
point. If the subject has been randomized to the block group, a subcutaneous lidocaine skin
wheel placed will be placed followed by a quadratus lumborum regional block with 40 ml, 0.25%
ropivacaine deposited deep to the transversus abdominus apnoneurosis and superficial to the
fascia transversalis with direct ultrasound guidance. Local anesthetic will be injected in 5
ml aliquots with aspiration for blood performed before and after the injection of each
aliquot. Local anesthetic injection will also be observed with real time ultrasound guidance.

Care in the perioperative period will otherwise be standardized. As part of routine care, all
patients will receive general anesthesia. After receiving 100µg of fentanyl intraoperatively,
hydromorphone or morphine will be administered and titrated by the anesthesia care team for
postoperative pain control. In the post-anesthesia care unit (PACU), hydromorphone or
morphine would continue to be titrated by the PACU nurse for the patient's comfort. The total
opioids administered after the initial 100µg of fentanyl would be compared between groups in
order to evaluate the effect of the quadratus lumborum block.

Data collection will begin after informed consent is completed. Data collection will include
demographic data, operative date/time, medications administered intraoperative and
postoperative, time to meet discharge criteria in PACU and visual analog scores (VAS) for
pain and satisfaction. VAS scores for pain will be collected prior to surgery, on PACU
arrival (when aware enough to do so) and upon meeting PACU discharge criteria. Patient
satisfaction will be recorded upon meeting PACU discharge criteria. Effects of the block
(numbness or motor weakness) will be recorded. Opioid side effects including nausea,
vomiting, and itching will also be noted. Patients will be called on postoperative day one to
assess block duration and satisfaction with care.

References

1. Colvin AC, Harrast J, Harner C. Trends in hip arthroscopy. J Bone Joint Surg Am 2012;
94: e23.

2. Montgomery SR, Ngo SS, Hobson T et al. Trends and demographics in hip arthroscopy in the
United States. Arthroscopy 2013; 29:661-5.

3. Sing DC, Feeley BT, Tay B et al. Age-related trends in hip arthroscopy: a large cross
sectional analysis. Arthroscopy 2015; 31:2307-13.e2.

4. Safran MR. Advances in hip arthroscopy. Sports Med Arthrosc 2010; 18:55. 5. Khanduja V,
Villar RN. Arthroscopic surgery of the hip: current concepts and recent advances. J Bone
Joint Surg Br 2006; 88:1557-66.

5. Zhang Z, Zhu W, Zhu L et al. Efficacy of celecoxib for pain management after
arthroscopic surgery of hip: a prospective randomized placebo-controlled study. Eur J
Orthop Surg Traumatol 2014; 24:919-23.

6. Ward JP, Albert DB, Altman R et al. Are femoral nerve blocks effective for early
postoperative pain management after hip arthroscopy? Arthroscopy 2012; 28:1064-9.

7. Lee EM, Murphy KP, Ben-David B. Postoperative analgesia for hip arthroscopy: combined L1
and L2 paravertebral blocks. J Clin Anesth 2008; 20:462-5.

8. Zhang Z, Zhu W, Zhu L et al. Efficacy of celecoxib for pain management after
arthroscopic surgery of hip: a prospective randomized placebo-controlled study. Eur J
Orthop Surg Traumatol 2014; 24:919-23.

9. Hansen CK, Dam M, Bendtsen TF, Børglum J. Ultrasound-Guided Quadratus Lumborum Blocks:
Definition of the Clinical Relevant Endpoint of Injection and the Safest Approach. A A
Case Rep. 2016 Jan 15;6(2):39.

10. Hockett MM, Hembrador S, Lee A. Continuous Quadratus Lumborum Block for Postoperative
Pain in Total Hip Arthroplasty: A Case Report. A A Case Rep. 2016 15;7(6):129-31.

11. Johnston DF, Sondekoppam RV. Continuous quadratus lumborum block analgesia for total hip
arthroplasty revision. J Clin Anesth. 2016;35:235-237.

Inclusion Criteria

- Age greater than or equal to 18 years-old

- Undergoing elective hip arthroscopy. Exclusion Criteria

- Local anesthetic allergy

- Chlorhexidine allergy

- Patient weight < 40kg

- Patient is currently pregnant

- Patient is unable or chooses not to give informed consent

- Emergency surgery

- Known preoperative substance abuse

- Preoperative opioid use for over three months