2
Hysterectomy is one of the most common gynecologic
procedures, increasingly performed through minimally
invasive surgical (MIS) approaches [1,2]. MIS is associated
with many advantages, including decreased blood loss,
shorter hospital stays, and often same-day discharge [3,4].
Many factors are involved in predicting successful same-
day discharge, including pain scores and narcotic use in the
postanesthesia care unit [5-8]. The Enhanced Recovery
After Surgery (ERAS) protocol is effective at optimizing
postoperative analgesia through nonopiate strategies,
including preemptive medication administration and
regional anesthesia [9,10].
The transversus abdominis plane (TAP) block is a non-
opioid, regional anesthesia intervention involving local
anesthetic infiltration into the anterior abdominal wall sen-
sory afferents coursing in the transversus abdominis neuro-
fascial plane at the triangle of Petit [11,12]. There have
been several studies demonstrating its efficacy in reducing
pain after MIS surgeries [12-14].
However, to our knowledge, prior studies analyzing the
effect of TAP block timing, pre- or postoperatively, either
have not clearly elucidated its impact or involved a differ-
ent population, such as abdominal hysterectomy or colorec-
tal surgery patients [15-18]. A difference, if present, will
aid clinicians in operative planning to maximize pain con-
trol. Currently, the timing is commonly decided based on
clinician availability, as there is no available evidence of
the impact of timing on postoperative pain control. The
goal of this study was to, therefore, investigate whether pre-
operative versus postoperative TAP block administration
would result in a greater reduction in postoperative opioid
use in patients undergoing MIS hysterectomy for benign
indications and to secondarily compare TAP block out-
comes against those of patients without receipt of a TAP
block.
Materials and Methods
The Legacy Health Institutional Review Board
(FWA00001280) approved the study protocol. Retrospec-
tive review was performed on patients who underwent a
minimally invasive hysterectomy (including laparoscopic
and robotic approaches) between January 2018 through
December 2022 in the Legacy Health System in Oregon.
Patients who underwent total hysterectomy for benign
gynecological disease were eligible for the study. Exclusion
criteria included a diagnosis of gynecologic malignancy,
concurrent urogynecological procedure, a total vaginal hys-
terectomy, or a supracervical hysterectomy. Additionally,
patients with baseline narcotic use, defined as opioid use
within the 3 months before surgery, were excluded from the
study. Patients were identified via Current Procedural Ter-
minology code for laparoscopic hysterectomy and laparo-
scopic-assisted vaginal hysterectomy, including 58550-
58554 and 58570-58573. Patients received TAP blocks
from anesthesia providers, and there was no standardized
Journal of Minimally Invasive Gynecology. Vol 00, No 00, 00 2023
TAP block medication composition or technique across all
patients. Data on medications and techniques used for TAP
block administration was collected. Additionally, there was
no standardized approach to postoperative multimodal pain
management, as this was provider dependent.
Data collection was performed through the electronic
medical record and included demographic data such as age,
weight, American Society of Anesthesiologists (ASA)
physical status, race, and ethnicity. Duration of surgery, a
diagnosis of endometriosis, and length of admission were
also collected. Milliequivalents of morphine were recorded
for a uniform analysis of opioid requirements and were cal-
culated between procedure end time and discharge from the
hospital. Both parenteral and oral administrations were
included in the analysis, with oral quantities being con-
verted to parenteral units for analysis. Additional clinical
outcomes were recorded, including postoperative numeric
rating system (NRS) pain scores, medication administration
for nausea/vomiting symptoms, and time to discharge.
Time to discharge was calculated from procedure end time
to discharge from the hospital in order to account for oper-
ating room delays. Procedure time was calculated using
time in and out of the operating room, thus incorporating
the approximate same amount of additional time required
for patients to receive a TAP block either preoperatively or
postoperatively. Medication administration records for
patients were analyzed to determine the number of adminis-
trations of antinausea or antiemetic medications before dis-
charge. Finally, the maximum recorded postoperative pain
score in relation to procedure end time was analyzed.
All statistical analyses were conducted using the R lan-
guage and environment for statistical computing [19]. Out-
comes were considered significant for p < .05. All
comparisons of demographic and clinical features were per-
formed using linear regression for continuous variables or
the Chi-Squared contingency table test for counts/propor-
tions. The main outcomes analyses were generated using
linear mixed effects regression or generalized linear mixed
effects regression depending on whether the outcome mea-
sure was continuous or counts/proportions, respectively.
All mixed effects models included the type of surgery
(defined by the CPT code) as a random effect driven by the
assumption that different types of surgery may produce dif-
ferent amounts of postoperative pain and, therefore, may
have required different amounts of postoperative opioids
and other medications to treat postoperative symptoms.
Several of the variable distributions (procedure duration in
minutes, total MME, time to discharge, and time to maxi-
mum pain score) were so heavily skewed that all regression
analyses involving those variables used the logarithm of the
original variable value.
Results
There were 2982 patients who underwent minimally
invasive total hysterectomy for benign gynecological