Comparison of Subacromial Injection and Interscalene Block for Immediate Pain Management Following Arthroscopic Rotator Cuff Repair

Journal Pre-proof Comparison of Subacromial Injection and Interscalene Block for Immediate Pain Management Following Arthroscopic Rotator Cuff Repair Benjamin D. Gross, BS, Steven A. Paganessi, MD, Oscar Vazquez, MD PII:

S0749-8063(20)30114-6

DOI:

https://doi.org/10.1016/j.arthro.2020.01.032

Reference:

YJARS 56769

To appear in:

Arthroscopy: The Journal of Arthroscopic and Related Surgery

Received Date: 18 July 2019 Revised Date:

7 January 2020

Accepted Date: 8 January 2020

Please cite this article as: Gross BD, Paganessi SA, Vazquez O, Comparison of Subacromial Injection and Interscalene Block for Immediate Pain Management Following Arthroscopic Rotator Cuff Repair, Arthroscopy: The Journal of Arthroscopic and Related Surgery (2020), doi: https://doi.org/10.1016/ j.arthro.2020.01.032. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2020 Published by Elsevier on behalf of the Arthroscopy Association of North America

Comparison of Subacromial Injection and Interscalene Block for Immediate Pain Management Following Arthroscopic Rotator Cuff Repair

Benjamin D. Gross, BS1, Steven A. Paganessi, MD2, Oscar Vazquez, MD1,2,3

1

Active Orthopedics and Sports Medicine, 25 Prospect Ave, Hackensack, NJ 07601

2

Hudson Crossing Surgery Center, 2 Executive Drive, Fort Lee, NJ 07024

3

Hackensack University Medical Center, Department of Orthopedics, 20 Prospect Ave,

Hackensack, NJ 07601

Acknowledgements: Patience Ajongwen, Msc, MPhil, PhD, MPH for her assistance with the statistical analysis.

IRB approval: Hackensack University Medical Center IRB (Study# Pro2019-0201)

Accepted for Podium Presentation: 1. OSET 2019 (Stryker Fellow, Resident & Medical Student Summit) 2. AAOS Annual Meeting 2020 3. AANA Annual Meeting 2020

Corresponding Author: Benjamin D. Gross Active Orthopedics and Sports Medicine 25 Prospect Ave Hackensack, NJ 07601 [email protected], (646)-709-1910

1

Comparison of Subacromial Injection and Interscalene Block for Immediate Pain Management

2

Following Arthroscopic Rotator Cuff Repair

3

“Subacromial Injection vs. Interscalene Block”

4

Abstract

5

Purpose: To compare the efficacy of a subacromial injection (SAI)to a single-shotinterscalene

6

block (ISB) for immediate postoperative pain relief following outpatient arthroscopic rotator cuff

7

repair (ARCR).

8

Methods: A retrospective chart review was performed on consecutive patients who underwent

9

ARCR. Patients received eitheran ISBbefore the procedure or an SAI after the procedure. Patient

10

preoperative baseline characteristics were collected and compared. Visualanalogue scale (VAS)

11

pain scores were recorded preoperatively, at 15-minute intervals overa 120-minute period in the

12

post-anesthesia care unit (PACU), and at discharge. Differences in VAS scores between

13

groupswere compared to known values for the minimal clinically important difference (MCID),

14

and the percentage of patients with VASscores below the patient acceptable symptom state

15

(PASS) weretabulated.Differences between preoperative characteristics were assessed using the

16

Mann-Whitney Uor Fisher exact Chi-square tests. Mann-Whitney U test was also utilized to

17

evaluate VAS scores and total time spent in PACU between groups.

18

Results:Median VAS score was significantly lower in the ISB group at PACU admission, at all

19

intervals throughout thePACU stay, and at discharge (p<0.0001). Median total timein PACU was

20

107 minutes (Q25-Q75: 90-120) and 210 minutes (Q25-Q75:175-274)for the ISB and SAI

21

groups, respectively (p<0.0001).Between-group differences in VAS scores were greater than the

22

MCID values at each measured interval. A total of 98% and 67% of patients in the ISB and SAI

23

groups were discharged with VAS scores below the PASS of 3, respectively.

24

Conclusions:Patients receiving ISB experience significantly less pain than those receiving SAI.

25

In addition, they are discharged home from the PACU in half the time as patients receiving SAI.

26

Based on the comparative efficacy, SAI cannot replace ISB following ARCR. ISB should

27

therefore remain the standard of care as an adjunct to postoperative analgesia for patients who

28

undergo outpatient ARCR.

29 30 31 32

Level of evidence:Level III, Retrospective comparative therapeutic trial.

33

Introduction

34

In light of the growing opioid epidemic, it has become increasingly important to explore

35

effective methods to control postoperative pain while limiting the use of both oral and parenteral

36

opioids. Rotator cuff repair has become the most commonly performed arthroscopic shoulder

37

procedure in the United States1,2and the trend towards outpatient arthroscopic rotator cuff repair

38

(ARCR)continues to grow.3,4In general, shoulder surgery, and particularly ARCR, has the

39

potential to generate significant postoperative pain. Therefore, as the search for alternative pain

40

management strategies advances, it is imperative to identify the most effective, simplest, and

41

safest methods to manage pain after surgery. With the rise in outpatient surgery, effective early

42

pain management is a critical factor that effects the ability to discharge patients in a timely

43

fashion.5

44 45

A single injection of intra-articular bupivacaine has been shown to provide varying levels of pain

46

relief following arthroscopic surgery at multiple surgical sites including the hip, knee, and

47

shoulder.6-9In the knee, combined bupivacaine and morphine intra-articular injectionshave been

48

compared to femoral nerve blocks.7Additionally, combined intra-articular injections were

49

superior to either one aloneand were equivalent to femoral nerve blocks for selected knee

50

procedures.In the shoulder, a single dose of intra-articular bupivacaine and morphine improves

51

pain relief following open rotator cuff repair.10Combined subacromial (SAI) and intra-articular

52

injections of bupivacaine have also been shown to improve pain control after ARCR.11Saito et

53

al.5concluded that combined periarticular injections, which included intrabursal injections of

54

bupivacaine and morphine, provided an easier, safer, and equally effective method of anesthesia

55

when compared to interscalene block (ISB) following ARCR. In a comparison

56

betweenintrabursal opioids and bupivacaine injections and ISB, Muitari et al.12 found that the

57

former was conceptually logical, technically simple, and offered fewer potential complications.

58 59

The use of ISB has been extensively studied as an effective adjunct to anesthesia for arthroscopic

60

shoulder surgery.13-18It is well accepted that ISB is useful and provides effective levels of

61

postoperative pain relief following outpatient arthroscopic shoulder surgery.19-23However,

62

concerns remain regarding its technical difficulty, potential for complications, and duration of

63

effectiveness.5, 24A recent study by Shin et al.25 demonstrated 61%of anesthesia-related

64

complications in shoulder arthroscopy are related to nerve blocks. If a safer, equally effective

65

technique could be identified, it could replace ISB as the preferred method of postoperative pain

66

management for ARCR.

67 68

The purpose of this study was to compare the efficacy of a subacromial injection (SAI) to a

69

single-shot interscalene block (ISB) for immediate postoperative pain relief following outpatient

70

arthroscopic rotator cuff repair (ARCR).We hypothesized that, compared to ISB, SAI would

71

provide greater than or equal postoperative pain relief following ARCR,and that it would not

72

adversely affect length of stay (LOS) in the PACU.

73 74

Methods

75

After obtaining approval from our Institutional Review Board, a single surgeon’s medical records

76

were queried for patients who underwent ARCR procedures between 1/1/2016 to 6/30/2018

77

using Current Procedural Terminology®Code 29827:Arthroscopy, shoulder, surgical; with

78

rotator cuff repair. This was a retrospective review, and no prospective trial was undertaken.

79

Allsurgerieswere performed at one of two free-standing ambulatory surgery centers (ASC) not

80

physically connected to a hospital.Thelocation of a given patient’s surgery was chosen according

81

to patient preference and convenience, withno consideration given toprocedure type, age, or

82

medical comorbidities. Patients were included if they underwent a single-rowARCR by the same

83

surgeon at either location 1 or 2and received either ISB or SAI. Patients were excluded if another

84

surgical technique (i.e. double-row repair) was employed, if receiving neither ISB nor SAI, if

85

open surgery was required, if they underwent a revision procedure, or if experiencing

86

complications intraoperatively or in the PACU.

87 88

Location 1 was an ASC affiliated with a teaching hospital,whichhad anesthesiology residents on

89

rotation. This had the potential to increase both the time and risks associated with performingan

90

ISB. Therefore,the treating surgeon’s patients(SAI group) at this location routinely received SAI

91

as an adjunct to pain management after shoulder arthroscopy. These patients received a single

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SAIof bupivacaine and morphine. Ten milliliters of 0.5% bupivacaine, 1:200,000 epinephrine

93

was combined with 0.5 milligrams of morphine and injected in the subacromial space with a 22-

94

gauge spinal needle by the surgeonafter the procedure. The injections were performed after the

95

arthroscopic equipment was withdrawn from the shoulder to prevent dilution. A single site free-

96

hand injection was utilized. Guidance with ultrasound, image intensification, or direct

97

arthroscopic visualization was not employed.

98 99

Location 2 was a physician-owned ASC that had noanesthesiologyresidents working in the

100

facility. At this location, all of the surgeon’s patients(ISBgroup) received a preoperative ISB by a

101

board-certified anesthesiologist experienced in regional anesthesia techniques. A standard

102

technique was employed by the anesthesiology group at this location. Each ISB was

103

administeredwith the patient in the supine positionand under conscious sedation withmidazolam

104

and fentanyl. The brachial plexus was located by ultrasound, at which point a 22-gauge, 2-inch

105

insulated block needle was inserted. Using a nerve stimulator, a twitch of either the pectoral,

106

deltoid, triceps, biceps, or hand muscles at 0.4-0.5 mA was elicited. Then, 30-40 ml of an equal

107

mixture of 0.5% ropivacaine and 2% lidocaine with 1:200,000 epinephrine was injected in

108

divided doses after negative aspirations.

109 110

All ARCRs were performed by the samesurgeon using a single-row knotlessrepair. The surgical

111

procedures were performed with the patient in the beach-chair position.Briefly, once the tear was

112

debrided and the greater tuberosity was decorticated, two reverse horizontal mattress fibertapes

113

were placed in the rotator cuff; thetapes were then crossed and brought out through the lateral

114

portal. They were then fixed onto to the lateral cortex with two biocomposite fully threaded

115

suture anchors placed at a dead man’s angle. In addition, rip stiches were placed anteriorly and

116

posteriorly and secured with the same two anchors.

117 118

Locations 1 and 2 followed identicalpreoperative,postoperative, and discharge protocols and

119

procedures.A combination ofthe Wong-Baker FACES® Pain Rating Scale and Graphic/Numeric

120

Rating Scale was used at both institutionsfor the assessment ofvisual analogue scale (VAS)

121

scores(Figure 1). The VASwasadministered to each patient by a registered nurse at admission

122

pre-operatively, on entrance to the PACU, at 15-minute intervals during the length of the PACU

123

stay, and at discharge from the PACU. Both centers had standardized criteria for discharge.

124

Before patients qualified for discharge, all anesthetized patients at both locations required(1) a

125

minimum of 2sets of stable vital signs(2) a pain assessment score equal toor lower thanthe

126

admission score(3) at least 30 minutes elapsed since their last medication was administered.Once

127

the patientsqualified for discharge,they were evaluated by a registered nurse to ensure they(1)had

128

a steady gait with minimal assistance (unless the patient was admitted by wheelchair or

129

stretcher);(2)maintained O2 saturation >90% on room air;(3) had a normal gag reflex;(4) retained

130

fluids by mouth;(5) had a score between 8-10 on the Modified Aldrete Post Anesthesia Scale or

131

the same baseline admission score;(6) wereorientedregarding time, place, and date.

132 133

A complete chart review of the surgery day was carried out for all patients who met the inclusion

134

criteria. Patient preoperative baseline demographics were collected and included age, sex, body

135

mass index (BMI), and smoking history. To test for clinical significance, the difference in VAS

136

scores between groups at each interval was compared to relevant literature values for theminimal

137

clinically important difference (MCID)26-28. Additionally, the percentage of patients below a

138

specific VAS score, thepatient acceptable symptom state (PASS),was calculated. The secondary

139

outcome measure, LOS in the PACU, was calculatedfrom existing chart values as (time admitted

140

to PACU) – (time of discharge). All concomitant procedures (labral debridement, biceps

141

tenotomy, subacromial decompression, acromioclavicular resection, removal of loose body, and

142

lysis of adhesions) and corresponding diagnoses (torn labrum, torn biceps, impingement,

143

acromioclavicular arthritis, glenohumeral arthritis, adhesive capsulitis) were additionally

144

tabulated for each patient (Table 1).

145 146

A Mann-Whitney U test was performed to evaluate differences in thepostoperative pain score

147

and recovery time between groups. Descriptive analyses were performed with continuous

148

variables presentedas median with interquartile range or mean (± standard deviation),and

149

categorical variables aspercentages (n/N). Differences in baseline characteristics between groups

150

were assessed using the Mann-Whitney U test for continuous variables and either the Fisher

151

exact (when N<5) andChi-square test (when N>5) for categorical variables. All hypothesis

152

testing was two-tailed and p-values <0.05 were considered statistically significant. Statistical

153

analyses were performed with SAS® Release 9.4 (SAS Institute Inc., Cary, NC).

154 155

Results

156

Of the 187 consecutive patients queried, 9 patients who underwent a revision procedure, and 8

157

patients who received a double-row repair were excluded. No patients were excluded due to

158

complications. Thus, 170 met the inclusion criteria and were included in this review. There were

159

81 patients included from location 1 (SAI Group) and 89 patients at location 2 (ISB group). No

160

significant between-group differences were found in baseline characteristics including sex, BMI,

161

and smoking history(P>0.05) (Table 1).However, there was a significant difference in age

162

between groups (P=0.0016). Nevertheless, the age distribution of the groupswas similar and

163

representative of the studied age group, as the age 25th and 75thoverlapped between groups (Table

164

1). Concomitant procedures including rotator cuff repair, subacromial decompression, labral

165

debridement, removal of loose body, and lysis of adhesions, and the corresponding diagnoses f

166

rotator cuff tear, torn biceps, impingement, glenohumeral arthritis, torn labrum, and adhesive

167

capsulitis were also distributed equally between groups. There were, however, significant

168

differences between the two groups regarding the frequency of biceps tenotomy and

169

acromioclavicular joint resection, and the diagnosis of acromioclavicular arthritis. (Table 1)

170

171

Median VAS score at time of admission was 2.5 (Q25-Q75: 0.0-6.0) for the SAI group and 3.0

172

(Q25-Q75: 0.0-6.0) for the ISB group. These differences were not statistically significant

173

(P=0.355).

174 175

For each 15-minute interval after PACU admission (from 0 minutes until discharge),the

176

medianVASscore was significantly lower in the ISB groupthan in the SAI group (P < 0.0001,

177

Table 2). The differences between all VAS scores were found to be greater than the literature

178

MCIDs of 1.2, 1.3, and 1.4(Table 4).Compared to the SAI groupthere was a largerpercentage of

179

ISB patients consistentlybelow the PASS score of 3during the PACU stay (Table 3). MedianVAS

180

scores atdischarge were significantly lower in the ISB group (0 [Q25-Q75: 0-0]) than in the SAI

181

group (3 [Q25-Q75: 0-4, P < 0.0001) (Table 2). Additionally, 98% of the patients in the ISB

182

group were discharged with VAS score below the PASS of 3, compared to only 67% of SAI

183

patients below this value (Table 3). The median LOS in the PACU was significantly lower for

184

patients in the ISB group (107 minutes [Q25-Q75: 90-120])than for patients in the SAI group

185

(210 minutes [Q25-Q75: 175-274], P < 0.0001).

186 187

Discussion

188

ISB proved to be superior to SAI in all evaluated parameters. Specifically, VAS scores were

189

significantly lower in the ISB group on admission to the PACU, at all intervals during the PACU

190

stay, and at discharge from the PACU. Patients who received ISB alsospent approximately50%

191

less time in the PACU than the patients who received SAI. Our statistical analysis showed that

192

the difference in both the primary and secondary outcomesbetween the SAI and ISB groupswere

193

significant. We also found that ISBwas clinically superior to SAI. Based on these findings, our

194

hypothesis was rejected.

195 196

While the MCID is usually employed to evaluate the clinical effectiveness of an intervention in

197

one group26, 29, 30, we used it to compare the clinical effectiveness of two different modalities on

198

similar groups. Although not widely employed for groups, the MCID canbe defined at either the

199

individual or group level. Inferences made at the group level can inform the choice between

200

different treatments.31 Tashjian et al.26found thatthe MCID for the VAS score in patients with

201

rotator cuff disease was 1.4 after 6 weeks of conservative management. Gallagher et al.27

202

definedthe MCID for patients with acute pain as being 1.3, while Liu et al.28found a MCID for

203

the VAS score of 1.2 for pain following arthroscopic shoulder surgery.When examining the

204

difference in VAS between groups, our results show a clinical advantage for ISBin regard toall

205

the three listed values. Additionally, Tashjianet al.26defined thePASS for theVAS score as

206

beingbelow 3 in patients with rotator cuff disease. Considering this PASS value for our findings,

207

ISB was shown to be clinically superior in the immediate post-operative period. Nearly all

208

patients who received an ISB achieved a satisfactory statewhile in the PACU and at discharge,

209

whileSAI patients did not experience the same levels of satisfaction and one third were

210

ultimately discharged above the PASS score.

211 212

The two outcomes we chose to evaluate were the VAS Scores and LOS in the PACU. The

213

amount of medicine administered was not included as one of our outcomes. One could speculate

214

that since patients in the SAI group routinely had more pain, they subsequently received more

215

breakthrough pain medication in the PACU. If the scores had been similar between the two

216

groups, it would have been necessary to evaluate the administration of pain medication to see if

217

this contributed to the similar outcome. However, since the outcomes showed significant clinical

218

and statistical differences, we did not feel it was necessary to do so

219 220

No a priori power analysis was undertaken in this studysince this was a retrospective chart

221

review of patients that underwent arthroscopic rotator cuff repair during the period from

222

1/1/2016 to 6/30/2018.This time period was chosen to provide a large number of subjects and

223

avoid beta error. The central limit theorem (CLT) states that the sampling distribution of the

224

sample means approaches a normal distribution as the sample size gets larger — regardless of the

225

shape of the population distribution. A sample size equal to or greater than 30 is

226

considered sufficient for the CLT to be valid.Because there were more than 30 patients in each

227

group of our study, the CLT was valid and our sample size wassufficient to be able to detect any

228

differences between the two groups.Furthermore, our ad hoc analysis, confirms this

229

assumption.We found that a minimum of 13, 12, and 11 subjects would be required to show an

230

MCID of 1.2, 1.3, and 1.4, respectively. Sincemore subjects were includedin both the SAI and

231

ISB groups, our sample size was more than sufficient to show significant differences between

232

groups.

233 234

ISB is accepted as an effective method of anesthesia following arthroscopic shoulder surgery,

235

However, some surgeons are reluctant to employ ISB because it requires a longer time to

236

administer, which may delay the start of surgery32; moreover, there have been multiple

237

complications associated with this technique33. Although rare, these complications can be serious

238

and include hemodynamic instability, respiratory depression, cardiac arrest, pneumothorax, and

239

permanent nerve injury.33

240 241

We chose to evaluate the effect of SAI because it is commonly performed, simple to administer,

242

and has few, if any, reported complications5, 12. Given these reasons, if SAI was found to be an

243

effective modality for achieving postoperative analgesia, wehypothesized that it should be the

244

preferred anesthetic method employed by surgeons and could mitigate the concerns associated

245

with ISB. Since ARCR has become the most commonly performed arthroscopic shoulder

246

procedure in the United States1and the trend towards outpatient ARCR continues to grow3,4, we

247

believed that this wouldbe an especially relevant choice for our index procedure.

248 249

One study that compared combined subacromial and intra-articular injection of bupivacaine

250

alone to ISB34found that these techniques yielded comparable results for shoulder arthroscopy.

251

The authors concluded that although considered safe, ISB can be associated with adverse

252

effects;therefore, SAI plus intra-articular injection was a reasonable pain management alternative

253

following shoulder surgery.Muitari and Krivella12found that ISB was superior to SAI in terms of

254

pain scores and fentanyl use in patient-controlled analgesia. However, this difference was limited

255

to the first 6 hours. Previous studies that compared ISB to other methods found that ISB was

256

superior during the initial time spent in the PACU. The median LOS in the PACU for both

257

groups was under 4 hours in our study, which is within the more effective time period for ISB in

258

other studies.Indeed, in our study, the more effective early pain relief provided by ISB allowed

259

for discharge from the facility in nearly half the time.

260

261

Two recent studies compared multimodal periarticular injections, which included SAI, to single-

262

shot5or continuous ISB24. The first study found that periarticular injections were safer and

263

provided better pain relief after the initial 8 hours. They concluded that periarticular injections

264

had significantly less side effects and might be preferable to ISB16-24 hours after ARCR. The

265

second study found that continuous ISB was significantly superior in the initial postoperative

266

period upto 8-12 hours. In a third study by Abdallah et al.16, ISB was found to provide effective

267

analgesia up to 8 hours after shoulder surgery, with no clear benefits thereafter. In addition, the

268

authors found that patients receiving ISB can suffer rebound pain at 24 hours and, compared to

269

patients who did not receive an ISB, experience similar pain severity after 24 hours. However,

270

none of these previous studies evaluated the relative safety of ISB and SAI. The first two studies

271

differed from ours in that they evaluated multiple periarticular injections rather than a single SAI.

272

In addition, neither study was done in an outpatient setting.Nevertheless, our results are

273

similarsincewealso found ISB to be superior during the initial postoperative period, which indeed

274

facilitated earlier discharge. Since our study was a retrospective chart review for outpatient

275

ARCR, we did not evaluate pain relief after discharge. This can be addressed in future

276

prospective studies using self-recorded pain scores by the patients or their families after

277

discharge. However, given the statistical and clinical superiority of ISB in the early post-

278

operative period, we would be reluctant to undertake that study.

279 280

Nonetheless, our study shows the advantages of ISB over SAI regarding the ability to provide

281

pain relief in the PACU after ARCR. As per our chosen outcomes, ISB provided statistically and

282

clinically superior pain relief in the PACU, and expedited discharge from the facility. Although

283

ISB has risks, they are limited35,36 and can be decreased using ultrasound

284

guidance.33,37Furthermore, the complication rate is further decreased when the blocks are

285

administered by experienced anesthesiologists.38Therefore, since SAI is both statistically and

286

clinically inferior to ISB in the evaluated measures,SAI cannot replace ISB as the standard of

287

care for postoperative anesthesia after ARCR. Despite the risks associated with ISB, adverse

288

results are rare, and can be further mitigated with simple steps. ISB can also provide an opioid

289

sparing effect and reduce opioid related side effects in the first 12 and 24 hours postoperatively.16

290 291

Limitations

292

The present study has several limitations. First, tear size was not recorded. However, the single-

293

row technique was routinely used only for tears up to 2.5cm so it can be assumed that the groups

294

were largely uniform in regard totear size. Second, the frequency of biceps tenotomy and

295

acromioclavicular resection (along with the diagnosis of acromioclavicular arthritis) was

296

significantly greater in the SAI group. One could speculate that SAI was inadequate to control

297

pain in these sites, which contributed to the poorer result in that group. Finally, our study did not

298

address the amount of pain medication administered in the PACU. Most comparable

299

investigations have some measure of the amount of medication given. Although this is a

300

limitation in our study design, we do not believe that this would have changed the outcomes.

301 302

Conclusions

303

Patients receiving ISB experience significantly less pain than those receiving SAI. In addition,

304

they are discharged home from the PACU in half the time as patients receiving SAI. Based on the

305

comparative efficacy, SAI cannot replace ISB following ARCR. ISB should therefore remain the

306

standard of care as an adjunct to postoperative analgesia for patients who undergo outpatient

307

ARCR.

308 309 310 311 312 313 314 315 316 317 318 319

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430 431 432 433 434

Table 1. Preoperative Baseline Characteristics between Subacromial Injection (SAI) and Interscalene Block (ISB) patient groups.

Baseline Characteristics

BMI

Age

All Patients

SAI

ISB

(N = 170) 29.05 (25.2432.89)†† 29.74 ± 6.101†

(N = 89) 29.28 (21.8533.22)†† 30.409 ± 6.55†

(N = 81) 27.88 (25.0532.44)†† 29.02 ± 5.51†

58 (52-66)†† 58.517 ± 10.857†

60 (55-68)††

55 (61-75)†† 56.16 ± 9.475†

†

60.66 ± 11.618

Gender

P Value 0.203

*0.0016 0.873

Female

37.6 (64/170)**

37.07 (33/89)**

38.27 (31/81)**

Male

62.35 (106/170)**

63.92 (56/89)**

61.73 (50/81)**

Smoking Status

0.259

No

85.88 (146/170)**

88.76 (79/89)**

82.72 (67/81)**

Yes

14.12 (24/170)**

11.24 (10/89)**

17.28 (14/81)**

Rotator Cuff Tear

100 (170/170)**

100 (89/89)**

100 (81/81)**

Torn Biceps

59.42 (101/170)**

65.17 (58/89)**

53.09 (43/81)**

0.110

Impingement

82.35 (149/170)**

85.39 (76/89)**

79.01 (64/81)**

0.276

Acromioclavicular Arthritis

62.35 (106/170)**

73.03 (65/89)**

50.62 (41/81)**

Glenohumeral Arthritis

7.05 (12/170)**

6.74 (6/89)**

7.41 (6/81)**

0.866

Torn Labrum

41.76 (70/170)**

47.19 (42/89)**

34.57 (28/81)**

0.095

22.94 (39/170)**

28.09 (25/89)**

17.28 (14/81)**

0.094

Rotator Cuff Repair

100 (170/170)**

100 (89/89)**

100 (81/81)**

Subacromial Decompression

85.88 (146/170)**

86.52 (77/89)**

85.19 (69/81)**

Biceps Tenotomy

58.82 (100/170)**

66.29 (59/89)**

50.62 (41/81)**

Labral Debridment

42.35 (72/170)**

47.19 (42/89)**

37.04 (30/81)**

Acromioclavicular Resection

61.18 (104/170)**

71.19 (64/89)**

49.38 (40/81)**

Removal of Loose Body

0.59 (1/170)**

1.12 (1/89)**

0 (0/81)**

Lysis of Adhesions

22.35 (38/170)**

26.97 (24/89)**

17.28 (14/81)**

Post-Op Diagnosis

Adhesive Capsulitis Procedure

1

*0.003

1 0.804 *0.038 0.181 *0.0027 0.34 0.1313

435 436 437 438 439 440 441 442 443 444 445

NOTE. Values are [mean ± SD]† ; [% (n/N)]** ; Median (25th-75th percen'le)††. *Statistically significant (P < .05) by Fisher exact or Chi-square test.

Table 2.Median Verbal Analog Pain Scores (VAS) (0-10 scale) at 15 minute post-op intervals and discharge between Subacromial Injection (SAI) and Interscalene Block (ISB) patient groups. Time (Minutes) in PACU

ISB P-Value

(N = 89)

(N = 81) 0.0 (0.0-0.0)†

<.0001*

15

3 (0.0-6.5)† 5.5 (0-8.0)†

0.0 (0.0-0.0)†

<.0001*

30

5.0 (2.0-7.0)†

0.0 (0.0-0.0)†

<.0001*

45

†

4.5 (3.0-6.0)

†

0.0 (0.0-0.0)

<.0001*

60

4.0 (2.0-6.0)†

0.0 (0.0-0.0)†

<.0001*

75

5.0 (3.0-6.0)†

0.0 (0.0-0.0)†

<.0001*

90

4.0 (2.0-5.0)†

0.0 (0.0-0.0)†

<.0001*

105

4.0 (4.0-6.0)†

0.0 (0.0-0.0)†

<.0001*

120

3.0 (2.0-5.0)†

0.0 (0.0-0.0)†

<.0001*

Discharge

3.0 (0.0-4.0)†

0.0 (0.0-0.0)†

<.0001*

0

446 447 448 449 450 451 452 453 454 455

SAI

NOTE. Values are Median (25th-75thpercentile)†. *Statistically significant (P < .05) by Mann-Whitney U Test.

456 457 458 459 460

SAI ISB 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479

t=0 t=15 t=30 t=45 t=60 t=75 t=90 t=105 t=120 At minutes minutes minutes minutes minutes minutes minutes minutes minutes Discharge 56 36 36 34 43 29 48 23 52 67 (49/88) (32/88) (31/86) (30/88) (36/83) (14/48) (21/44) (6/26) (11/21) (60/89) 96 94 96 95 98 95 94 94 94 98 (73/76) (74/79) (77/80) (74/78) (78/80) (37/39) (33/35) (16/17) (15/16) (79/81)

Table 3.Percentage of patients below the patient acceptable symptom state (PASS) in the Subacromial Injection (SAI) and Interscalene Block (ISB) patient groups at 15 minutepost operative time intervals and at discharge. NOTE. Values are reported as % (n/N).

Table 4.Difference in Visual analogue scale (VAS) pain scores at postoperative intervals and at discharge for Subacromial Injection (SAI) and Interscalene Block (ISB) patient groups. Time (Minutes) in PACU

Median VAS (0-10) ∆VAS SAI

ISB

0

3.0†

0.0†

3.0††

15

5.5†

0.0†

5.5††

30

5.0†

0.0†

5.0††

45

4.5†

0.0†

4.5††

60

4.0†

0.0†

4.0††

480 481

75

5.0†

0.0†

5.0††

90

4.0†

0.0†

4.0††

105

4.0†

0.0†

4.0††

120

3.0†

0.0†

3.0††

Discharge

3.0†

0.0†

3.0††

NOTE. Values are Median†; [Median (ISB) at time interval x]- [Median (SAI) at time interval x] †† .

Figure 1: Wong-Baker FACES® Pain Rating Scale and Numeric Rating Scale used to determine VAS

Benjamin D. Gross:, Methodology, Investigation, Writing – Original Draft, Writing - Review & Editing, Visualization, Project Administration Stephen A. Paganessi: Conceptualization, Resources, Writing – Original Draft, Supervision Oscar Vazquez: Conceptualization, Methodology, Resources, Writing – Original Draft, Writing Review & Editing, Supervision, Funding Acquisition

Patience Ajongwen (Acknowledgements): Formal analysis