Volume Versus Concentration: A Prospective, Double Blind, Parallel Study to Compare the Clinical Effectiveness of Single Shot Quadratus Lumborum Block Using Either a High Volume/Low Concentration or Low Volume/High Concentration Injectate for Total Hip Arthroplasty.
Phase: PHASE4
Conditions: Acute Pain
Sponsor: Anna Uskova

STUDY TITLE: Volume versus concentration: A prospective, double blind, parallel study 
to compare the clinical effectiveness of single shot quadratus lumborum block using 
either a high volume / low concentration or low volume / high concentration injectate for 
total hip arthroplasty  
 
PRINCIPAL INVESTIGATOR: Anna Uskova, MD 
* Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh 
Medical Center, Pittsburgh, PA 
 
NCT #: 04259645 
 
IRB ID: STUDY19090192 
 
STUDY PROTOCOL 
 
DOCUMENT APPROVAL DATE: 01/16/2020 
 
 

Our sample size in based on a previous study by Yousef NK. Where the total dose of 
morphine/patient was used to calculate sample size. The sample size was found to be 
28 patients in each group assuming a standard deviation of 3.9 mg of morphine as 
rescue analgesic (from the pilot study), α error of 0.05, β error of 0.2, and a power of 
80%. We intended to include 30 patients in each group to compensate for excluded 
patients 
 
1.Yousef NK. Quadratus Lumborum Block versus Transversus Abdominis Plane Block 
in Patients Undergoing Total Abdominal Hysterectomy: A Randomized Prospective 
Controlled Trial. Anesth Essays Res. 2018 Jul-Sep;12(3):742-747. doi: 
10.4103/aer.AER_108_18. PubMed PMID: 30283187; PubMed Central PMCID: 
PMC6157234. 

Protocol title: Volume versus concentration: A prospective, double blind, 
parallel study to compare the clinical effectiveness of single shot quadratus 
lumborum block using either a high volume/low concentration or low 
volumen/high concentration injectate for total hip arthroplasty 
 
P.I: Anna Uskova M.D 
 
Co-Investigators:   Bruce Ben-David M.D 
                               Manuel Torres Grajales M.D 
                               Javier J. Polania M.D 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
 
 
Background 
 
The Quadratus Lumborum Block (QLB) was originally described by Blanco in 2007 (1) as 
a posterior variation of the Tranversus Abdominis Plane block. It is now, however,  
recognized as a unique,  alternative, and separate interfascial plane block. The QLB has 
been studied and compared with other types of blocks and it may offer several advantages 
such as simplicity, safety, and avoidance of hypotension. Additionally, dermatomal 
coverage may be greater than for other types of blocks.(2) In cadaveric studies the 
paravertebral spread of  dye was found from T7-L5 (3), although an vivo study in healthy 
volunteers showed the paravertebral spread of the contrast solution only between T10-L1 at 
1 hour after the block. (4) It is noted that while these anatomical studies invariably show 
the spread of contrast or dye extending to the paravertebral space that spread may be 
limited in degree. Thus follows a point of significant controversy as to whether the 
paravertebral space is in fact the block’s primary site of action or whether it acts primarily 
on nerves, radicular and sympathetic, situated in the thoracolumbar fascia. Questions of 
mechanism and site of action notwithstanding, the safety and clinical efficacy of this block 
has been clearly demonstrated in multiple types of surgeries including abdominal 
laparoscopic (5), open laparotomy (6), urologic (7,8), and general surgery (9) with 
analgesia lasting roughly 24 hours, decreased consumption of opioids, decreased time to 
ambulation, and decreased hospital length of stay. In recent studies, QL block employment 
was shown to produce a significant reduction in length of stay during hip surgery as well as 
similar analgesia to Lumbar Plexus blockade. 
 
The quadratus lumborum block has since 2016 become standard of care for abdominal and 
hip surgeries at our institution, replacing paravertebral and lumbar plexus blocks 
respectively, and as part of a broader multimodal analgesia institutional ERAS (Enhanced 
Recovery After Surgery) protocol. Coincident with its implementation we have seen 
significant reductions in opiate and PCA use as well as hospital length of stay. Similar 
results have been reported by other institutions.(10)  
 
Since the first description of this technique, several approaches to and anatomic targets 
within the quadratus lumborum plane have been described although their mechanism of 
action, spread, and relative clinical effectiveness remain areas of some debate. There 
remain many unanswered questions regarding this block and its subtypes. It is, for example, 
unknown if one technique would be better than another for different types of surgery. 
Likewise little is known of the relative importance of local anesthetic concentration and 
injectate volume - the principal question addressed by this proposed study.  
 

 
 
 
 

Specific Aims 
 
1. This study will prospectively investigate the efficacy of two different volumes of 
preoperative single shot local anesthetic solution injected using the QLB lateral 
approach (Quadratus Lumborum Block type I; QLB I) in patients undergoing total 
hip arthroplasty. The primary outcome will be consumption of opioids during the 
first 24 hours after surgery. 
 
2. Secondary outcomes will include: 
 Pain measurement through VAS (Visual Analogue Score) at rest and with 
movement at 3, 6, 12, and 24 hours after surgery hours after surgery  
 Consumption of non narcotic medication during the first 24 hours after 
surgery. 
 Time to ambulation after surgery (ability to walk 100 feet). 
 Hospital length of stay. 
 Time to consumption of the first opioid after surgery. 
 Patient satisfaction 24 hours after surgery. 
 Presence of any adverse effect related with analgesic technique 
 
 
 
Hypothesis 
 
There will be a significant difference between the higher and lower volumes on opioid 
consumption during the first 24 hours after surgery. 
 
 
 
Study Design 
 
The study will be conducted as a prospective, randomized, double blinded, parallel trial at 
the University of Pittsburgh Medical Center (UPMC) Shadyside Hospital. Institutional 
Review Board approval will be obteined before elegible patients are recruited and 
consented. Trial will be registered at www.Clinicaltrials.gov before beginning recruitment. 
 
 
 
Recruitment  
 
Potential subjects will be recruited in the preoperative area of Shadyside hospital on the day 
of their scheduled nephrectomy. Patients who agree to participate in the trial will be asked 
to sign an IRB approved informed consent form. 60 patients are expected be enrolled in this 
trial with 30 in each group. 
 
 
 
 

Randomization process 
 
Participating patients will be randomized by computer generated random allocation to have 
both of the  QLBs performed with either Low Volume [ropivacaine 0.75% x 20 mL] or 
High Volume [ropivacaine 0.375% x 40 mL] injectate. All blocks will have the standard 
additives of dexmedetomidine  0.4 mcg/kg (max dose 30 mcg for age <70, max dose 20 
mcg for age >70) + dexamethasone 4 mg. 
 
 
Inclusión criteria 
 Patients 18-90 years old 
 Patients undergoing total hip arthroplasty 
 BMI 19-45, >40 kg 
 Male and Female 
 All races 
 ASA I, II, III 
 Spinal Anesthesia Provided 
 
Exclusion Criteria 
 Patient refusal 
 Pregnancy 
 Non english speaking or inability to participate in the study 
 Patients with coagulopaty or With INR >1,5 the day of the surgery. 
 Chronic steroid use 
 Chronic pain 
 Chronic opiate use  
 
Treatment Groups: 
 
Both groups will receive QLBI as described below:  
 
With the patient in the lateral position and following sterile prep and draping,  a low 
frequency curvilinear ultransound probe with sterile cover is positioned transversely 
between the iliac crest and the costal margin at the level of the anterior axillary line. The 
three muscle layers of the lateral abdominal wall (external and internal obliques, 
transversus abdominis) are identified and traced postero-laterally until the transversus 
abdominis tapers off into its hyperechoic aponeurosis. At this point the QL muscle is 
identified deep and lateral to the aponeurosis. The probe is advanced further postero-
laterally to position the quadratus muscle mid-screen on the ultrasound. A 22-g Tuohy 
needle is inserted in plane from anteromedial to posterolateral to position the needle tip at 
the interfascial plane  deep to the thoracolumbar fascia and superficial to the Quadratus 
Lumborum muscle. The optimal point of injection is determined using hydrodissection 
(QLB 1).(6) 
 
Group Low Volume: 30 subjects randomized to Low Volume will receive QLBI. Each 
block of 0,75% ropivacaine x 20 mL +  dexmedetomidine  0.4 mcg/kg (max dose 30 mcg 
for age <70, max dose 20 mcg for age >70) + dexamethasone 4 mg 

 
Group High Volume:  30 subjects randomized to High Volume will receive QLBI. Each 
block of 0,375% ropivacaine x 40 mL  +  dexmedetomidine  0.4 mcg/kg (max dose 30 mcg 
for age <70, max dose 20 mcg for age >70) + dexamethasone 4 mg 
 
 
Anesthetic management 
 
Participants in both treatment groups will receive standard ERAS multi-modal analgesic 
pre-operatively (celebrex 200 mg PO and acetaminophen 1000 mg PO) and will receive the 
estándar ERAS anesthestic technique intraoperatively (spinal neuroaxial block with 
hyperbaric bupivacaine in estándar doses 1.4-1.6 ml), introperative propofol infusion(50-
100 mcg/kg/min) intravenous dexmedetomidine (12-20 mcg) infusion, and intravenous 
ketamine (20mg). 
Patients will receive antiemetic prophylaxis with haloperidol 0.5 – 1.0 mg IV 
intraoperatively and rescue ondansetron 4 mg IV in PACU. All patients will receive 
standard ERAS fluid management intraoperatively. Postoperative pain management will 
also follow standard ERAS protocol to include acetaminophen 1000 mg PO q6h, 
gabapentin 300 – 600 mg PO qhs, PO ketamine 10-30 mg q8hrs, celecoxib 200 mg PO 
BID. Rescue analgesic medication will include Oxycodone 5 – 10 mg q4hr PRN, and 
hydromorphone 0,2 – 0.4 mg IV q1hr for severe pain (VAS>5). 
 
 
Data collection and Outcome Measures 
 
Once the patient has signed the informed consent document they will be randomly assigned 
to one of the two study groups as described. Only the persons administering the block will 
be unblinded to the patient’s group assignment.  Both the patient and the outcome assesors 
will be blinded to that assignment.  
 
 Primary outcome: VAS pain score at 3, 6, 12, and 24 hours after surgery will documented 
by one of the Investigator.  Patients will also asked to respond on a scale (Liker Type) from 
1-5 how would he/she describe the pain management during the first 24 hours after surgery. 
Other variables such as total opioid consumption, length of hospital stay, consumption of 
non narcotic analgesics,and time to consumption of the first opioid after surgery will be 
abstracted from the electronic medical record. 
 
 
Statistical analysis plan 
 
Continuous patient/procedure variables (age, weight, height, body mass index, duration of 
surgery, length of stay, morphine equivalent opiate analgesic requirement, visual analog 
pain scales, time to the first opioid requeriment after surgery) will be analyzed using t test 
(normally distributed data) or Rank sum test (for not normally distributed data). 
Dichotomous variables (gender, incidence of complications eg. postoperative nausea and 
vomiting, and analgesia related complications) will be analyzed by Chi square and Fischer 
exact test. SPSS and Stata programs will be used for statistical analysis. 

 
 
 
 
 
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