Pneumonectomy in Dogs and Cats

Outcome after pneumonectomy in 17 dogs and 10 cats: A Veterinary Society of

Surgical Oncology Retrospective Study

Wavreille V1, Boston SE1, Souza C1, Ham K2, Chanoit G3, Rossetti D4, Takacs J5,

Milner R1

1Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL

2Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Ohio State University, Columbus, OH

3School of Veterinary Sciences & Bristol CardioVascular, University of Bristol, University of Bristol, Langford, UK

4Small Animal Surgery Department, Centre Hospitalier Vétérinaire Frégis, Arcueil, France

5Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA

1

1

2

3

4

5

6

7

8

9

10

11

12

13141516171819202122232425262728

29

30

31

32

33

34

35

36

37

38

ABSTRACT

Objective: (1) To report signalment and outcome data from dogs and cats undergoing

pneumonectomy; and (2) to document presenting clinical signs, surgical

complications, histologic diagnosis, and postoperative complications.

Study Design: Retrospective, multicenter study.

Sample Population: Seventeen dogs and ten cats.

Methods: Signalment, clinical signs, side affected, surgical data, pre-operative

diagnostic tests (including complete blood count, serum biochemistry, cytological

diagnosis, chest radiographs and computed tomography), histopathologic diagnosis,

surgical complications, adjunctive therapy, and date and cause of death were collected

from records of dogs and cats that underwent pneumonectomy. Survival estimates,

and complication were assessed.

Results: Seventeen patients had a left-sided pneumonectomy performed (12 dogs

and 5 cats) and ten patients had a right-sided pneumonectomy (5 dogs and 5 cats).

Fourteen patients were diagnosed with neoplasia (52%). The overall incidences of

complications were 76% and 80% for dogs and cats, respectively. The incidences of

major complications were 41% and 50% for dogs and cats, respectively. Respiratory

complications (persistent pleural effusion, oxygen dependence, persistent increased

respiratory rate or coughing) were the most commonly reported complications. No

patients died or were euthanized intraoperatively or within the first 24 hours post

operatively. However, one dog (6%) and 2 cats (20%) died or were euthanized in the

first 2 weeks post-operatively.

Conclusion: Based on this small cohort, right and left pneumonectomy can be

performed with a relatively low perioperative mortality rate in dogs and cats, with

some animals experiencing prolonged survival.

2

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

64

INTRODUCTION

Pneumonectomy, defined as surgical excision of the entire left or right lung, is an

uncommonly performed procedure in veterinary surgery. A small number of reports

have described outcome after pneumonectomy in companion animals1-4 and two of

these reports were not directly focused on the clinical outcome: one study3 assessed

the impact of the procedure on the right-side of the heart and the second report was

focused on the anesthesia and perioperative management of a pneumonectomized

dog.4 Factors associated with perioperative mortality, complications or successful

outcome remain largely unknown in dogs and cats.

This procedure has also been reported in clinically normal research dogs. Because of

the differential in lung volume between the right and left lung, it has been reported

that removal of more than 60% of the lung volume can lead to potentially fatal

pulmonary hypertension.5,6 A left-sided pneumonectomy is considered to be better

tolerated as the left lung represent 42% of the lung volume.6 It has also been

suggested that in some slow and progressive disease processes, a right

pneumonectomy is a possible treatment option because of compensation of the

remaining functional lung.2,6 Experimental studies performed in healthy dogs showed

increased pulmonary vascular resistance and right ventricular hypertrophy after left

pneumonectomy but pulmonary arterial pressure remained within the normal

reference range.7,8 There is also evidence of compensation via more efficient oxygen

transport across the alveoli after pneumonectomy exceeding 50% of the lung volume.

This has been explained by three principal mechanisms: recruitment of physiologic

3

6566

67

68

69

70

71

72

73

74

75

76

77

78

79

80

81

82

83

84

85

86

87

88

89

reserves of diffusing capacity, remodeling of the existing alveolar-capillary network,

and new or regenerative alveolar-capillary growth.8-12

In contrast to veterinary medicine, outcome following pneumonectomy in humans is

reported in numerous studies.13-15 It is associated with a high morbidity and mortality

rate in people13. Three recent studies reported a 30 day mortality rate of 5.1%13, 14 and

5.7%15 in pneumonectomy patients operated for cancer. Rivera et al reported a

postoperative in-hospital mortality rate of 22.1% for pneumonectomy patients treated

for benign disease.13 In a recent review,16 morbidity rates between 25 to 60% were

reported. The primary indication for pneumonectomy in human medicine is the

treatment of lung cancer.13 In the 14 cases in the veterinary literature, seven were

treated for neoplasia.1-4

Because pneumonectomy is uncommonly performed in veterinary medicine,

information about the procedure, success-rate and complications are lacking.

Our aims in this retrospective, multi-institutional Veterinary Society of Surgical

Oncology (VSSO) study were: (1) to report signalment and outcome data from a

relatively large number of dogs and cats undergoing pneumonectomy; and (2) to

document presenting clinical signs, histologic diagnosis, potential prognostic factors,

and complications. We hypothesized that right and left pneumonectomies are not

associated with a poor outcome.

4

90

91

92

93

94

95

96

97

98

99

100

101

102

103

104

105

106

107

108

109

110

111

112

113

MATERIAL AND METHODS

This study was approved by the Veterinary Society of Surgical Oncology (VSSO)

research committee and was initiated by requesting case submissions from VSSO

members through the VSSO list-serve. Medical records from contributing institutions

were searched to identify dogs and cats that had had pneumonectomy. Inclusion

criteria for this study were dogs and cats underwent pneumonectomy between 2004

and 2014 for neoplastic and non-neoplastic causes. Cases were excluded if there was

not a histopathological diagnosis of the underlying disease and if a subtotal

pneumonectomy was performed, defined as preservation of one or more lung lobes on

the affected side. Data retrieved included: sex, breed, age, weight, clinical signs, side

affected, surgical data (including surgical approach, method for lobectomy, and

whether or not tracheobronchial lymph nodes were removed), preoperative diagnostic

tests (including complete blood count, serum biochemistry, cytologic diagnosis,

thoracic radiographs and computed tomography (CT), histopathologic diagnosis,

perioperative and postoperative surgical complications, reason for performing a

pneumonectomy if not planned prior to surgery, adjunctive therapy if any, and date

and cause of death. Animals were classified by the underlying disease as having

neoplastic or non-neoplastic disease as the reason for pneumonectomy. Complications

were classified in 2 groups: major and minor complications. They were also evaluated

as intraoperative and post-operative complications. Major intraoperative

complications were defined as complications necessitating direct surgical

management or cardiopulmonary resuscitation. Major complications were defined as

any complication that was life threatening (serious complications that could cause

death without urgent support), resulted in a second surgical procedure, death or

5

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

euthanasia. Minor complications were defined as self-limiting or medically managed

complications. Complications were also defined by the time-frame in which they

occurred, including intra-operative complications, and (within 14 days) and late

(greater than 14 days) post-operative complications. The overall incidence, severity

and time frame of complications was reported.

Statistical analysis

Statistical software (GraphPad Prism version 5.00 for Mac OS X, GraphPad Software,

San Diego California USA, www.graphpad.com) was used to generate descriptive

statistics and median survival time (MST). Survival time was defined as the time

between pneumonectomy and death. The cause of death was classified as either

disease‐related or non-disease related. Patients with an unknown cause of death were

presumed to have died from disease‐related causes. Patients that died because of non‐

disease related causes or were lost to follow up were censored for the survival

analysis. Kaplan–Meier survival plots as well as mean survival times and MSTs were

calculated.

6

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

RESULTS

Signalment

Seventeen dogs and ten cats met the inclusion criteria for this study (9 institutions

participated to this study). The median age of the dogs was 86 months (range, 3-164

months). There were seven male and ten female dogs. The median body weight of the

dogs was 22.6 kg [range, 0.8–52.4 kg] of various breeds (Table 1).

Of the ten cats, the median age was 84 months [range, 6–181 months]. There were 7

male and 3 female cats. Domestic short hair cats were the most common breed

represented (n=7). The median weight was 4.5 kg [range, 2.2–6.5 kg] (Table 2).

Presenting complaint

Most of the patients (21/27, 78%) presented with respiratory signs such as difficulty

breathing and/or coughing. All of the cats and 11 dogs presented for respiratory signs.

Five dogs (19%) were referred for non-specific clinical signs such as lethargy,

inappetence and exercise intolerance. For one dog, the lung mass was an incidental

finding, diagnosed on thoracic radiographs during staging for a cutaneous melanoma.

Pre-operative diagnostic tests

All patients had full serum biochemistry and complete blood count performed prior to

surgery. In one case, the results were not available for review. Leukocytosis was

reported in nine cases, with five of these cases (5/13, 38%) ultimately diagnosed with

non-neoplastic disease and four of these cases (4/14, 29%) diagnosed with neoplasia.

Albumin was decreased in seven cases (7/27, 26%), four of these cases were

diagnosed with non-neoplastic disease (4/13, 31%).

7

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

Thoracic radiographs were performed in 25 (93%) cases. Computed tomography (CT)

was performed for 15 cases (56%). Among these 15 cases, lesions involving the entire

right or left lung lobe were described for 7 cases (47%). For the remaining 8 cases,

extension of the lesion was limited to a part of the lung (left cranial lung lobe, left

caudal lung lobe or right cranial and middle lung lobes) but for 3 cases (cases 6, 17

Table 1 and case 1, Table 2), the mass was described in close association with the

hilus. For one case, a foreign body was identified (case 16, Table 1). Compression of

the right lung by a thoracic wall mass causing increased density of the right lung lobes

was described for one case (case 14, Table 1) on CT. Between 2004 and 2009, a third

of the patients (3/9) had a CT prior surgery, whereas 2/3 of patients (12/18) had a

preoperative CT between 2009 and 2014.

Pneumonectomy

Seventeen patients had a left-sided pneumonectomy performed and ten patients had a

right-sided pneumonectomy. A lateral thoracotomy was employed in 22 patients at the

4th to 6th intercostal space. The intercostal space was not recorded in one patient that

had a lateral thoracotomy. A median sternotomy was performed in five patients, for

left (n=4) or right (n=1) pneumonectomy. A thoracic wall resection (6th and 7th ribs)

combined with a right-sided pneumonectomy was performed in one case (case 14,

Table 1). One case was a completion pneumonectomy for a pulmonary abscess as the

right cranial lung lobe had been partially removed for treatment of a spontaneous

pneumothorax 2 months previously (case 17, Table 1). Hemostasis and pneumostasis

were achieved with a surgical stapler alone in 16 cases (56%) (thoraco-abdominal

stapling device n=15, gastrointestinal anastomosis device n=1). A hand suture ligation

8

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

211

212

213

technique was used in four cases. A combination of surgical stapler and hand suture

ligation was used in three cases and a combination of a surgical stapler and hemoclips

was used in one case. Hemoclips alone were used for one case (case 3, Table 2). For 2

cases, the surgical technique was not recorded.

For eight cases, the pneumonectomy was unplanned. The reported reason for

performing an unplanned pneumonectomy was unexpected consolidation of the other

lung lobes (case 13 and 9, Table 1), unexpected diffuse disease (expanding to the

entire right or left lung) (case 2 Table 1 and case 1, Table 2), presence of adhesions

between the mass/affected lung lobes and the other lung lobes (case 6, 16 and 17,

Table 1), or pulmonary involvement of a chest wall mass (case 14, Table 1).

Tracheobronchial lymph nodes were removed and submitted for histopathology in six

cases (22%, 4 dogs and 2 cats) and sampled via intraoperative fine needle aspiration

for cytology in one case (4%, one cat). This cytology was consistent with reactive

lymphoid hyperplasia. Histopathology reports were available for 2 dogs and revealed

sinus histiocytosis with multifocal pyogranulomatous inflammation for one dog

diagnosed with a chronic hemorragic pleuritis (case 16, Table 1) and metastasis of

pulmonary carcinoma for the other dog (case 15, Table 1).

Surgical complications and outcome

Dogs – Intraoperative complications

Intraoperative complications were recorded in 5 cases (29%). Two cases had major

complications (12%) and included hemorrhage (n=1) and cardiac arrest (n=1). Minor

complications occurred in 3 dogs (18%) and included: hypotension (n=2) and

9

214

215

216

217

218

219

220

221

222

223

224

225

226

227

228

229

230

231

232

233

234

235

236

237

238

hypothermia (n=2). One case developed both hypothermia and hypotension. The case

that developed hemorrhage received a blood transfusion during the procedure. The

patient that developed cardiac arrest was resuscitated successfully. Intra-operative

death was not reported.

Dogs – Early Postoperative Complications (0-14 days)

Early postoperative complications were recorded in 12 cases (71%). Four cases had

major complications (24%) and included persistent pleural effusion (n=2), oxygen

dependence (n=2) and cardiac arrest (n=1). Minor complications occurred in 12 cases

(71%) and included: anemia (n=3), anorexia (n=2), regurgitation/vomiting (n=2),

coughing (n=2), hypertension (n=1), hypotension (n=1), hypothermia (n=1),

tachycardia (n=1), second degree atrioventricular block (n=1), phlebitis (n=1), nausea

(n=1), hypoglycemia (n=1), incisional infection (n=1), persistent increased respiratory

rate (n=1), infection pressure sores right front leg (n=1), and suspected immune

mediated vasculitis (n=1). The dog that developed cardiac arrest at day 10 post

operatively died (case c1, Table 1) in the hospital. This young dog (3 months old) was

diagnosed with a marked, severe, bronchopneumonia with pulmonary necrosis and

abscess formation. The bacterial culture revealed Bortella bronchiseptica.

Dogs – Late Postoperative Complications (>14 days)

Late postoperative complications were recorded in 6 cases (38%). Three cases had

major complications (19%) and included persistent pleural effusion (n=1),

degradation of the clinical status leading to euthanasia due to persistent pleural

effusion and suspected carcinomatosis (n=1), and draining tract on the cranial aspect

of the sternum (n=1) that led to surgical removal of a sternal sequestrum. Minor

10

239

240

241

242

243

244

245

246

247

248

249

250

251

252

253

254

255

256

257

258

259

260

261

262

263

complications occurred in 3 cases (19%) and included: coughing (n=2), vomiting

(n=1) and exercise intolerance (n=1). One case developed vomiting and coughing.

Overall, complications were recorded in 13 dogs (76%). Seven cases had major

complications (41%) and 12 cases had minor complications (71%). Three dogs with a

right pneumonectomy (60%) and 4 dogs with a left pneumonectomy (33%) had

major complications.

Cats – Intraoperative complications

Intraoperative complications were recorded in 2 cases (20%). One case had a major

complication (10%), and was hemorrhage. Minor complication (10%) occurred in one

case, and was hypotension. The case that developed hemorrhage received a blood

transfusion during the procedure. Intra-operative death was not reported.

Cats – Early Postoperative Complications (0-14 days)

Early postoperative complications were recorded in 8 cases (80%). Four cases had

major complications (40%) and included persistent pleural effusion (n=1), tension

pneumothorax (n=1), need for assisted ventilation (n=1), oxygen dependence (n=1),

and deterioration of the clinical status leading to euthanasia (n=2) (both cases were

treated for major respiratory complications). Minor complications occurred in 8 cases

(80%) and included: anemia (n=5), regurgitation/vomiting (n=1), anorexia (n=2),

hypoalbuminemia (n=1), fever (n=1), hypotension (n=1), diarrhea (n=1) and

persistent increased respiratory rate (n=1).

Cats – Late Postoperative Complications (>14 days)

11

264

265

266

267

268

269

270

271

272

273

274

275

276

277

278

279

280

281

282

283

284

285

286

287

288

Late postoperative complications were recorded in 3 cases (43%). One case had a

major complication (14%), and was persistent pleural effusion. Minor complications

occurred in 2 cases (29%) and included: coughing and regurgitation/vomiting.

Overall, complications were recorded in 8 cats (80%). Five cases had major

complications (50%) and 8 cases had minor complications (80%). Three cats with a

right pneumonectomy (60%) and 2 cats with a left pneumonectomy (40%) had major

complications.

Cytological and histological outcome

Pre-operative cytology was performed in 18 cases (67%). Non-diagnostic results and

neoplasia were diagnosed in 4 cases each (22%). Of the cases diagnosed with

neoplasia on cytology, four had a neoplastic diagnosis confirmed on histopathology.

Suppurative or septic suppurative inflammation was reported for the remaining ten

cases (56%). Of the cases that had a preoperative cytological diagnosis that was

inflammatory or infectious, seven had this diagnosis confirmed on histopathology and

three were ultimately diagnosed with neoplasia.

Fourteen patients (52%) were diagnosed with neoplasia on histopathology: 10 dogs

and 4 cats. Ten cases were diagnosed with pulmonary adenocarcinoma (6 dogs and 4

cats), one dog with a chest wall chondrosarcoma, one dog with bronchogenic

adenoma, one dog with metastasis of an oral squamous cell carcinoma, and one dog

with metastasis of a cutaneous myxoid soft tissue sarcoma.

An infectious process (including pneumonia, bronchopneumonia, or pulmonary

abscess) was diagnosed in 6 dogs and 5 cats. Among these, a foreign body was

12

289

290

291

292

293

294

295

296

297

298

299

300

301

302

303

304

305

306

307

308

309

310

311

312

313

identified for 2 cases. Only two cases were diagnosed with non-infectious disease.

These included a cat with severe chronic pleuritis associated with atelectasis,

pulmonary artery medial hypertrophy, eosinophilic arteritis, periarteritis, and focal

arterial mineralization; and a dog with a cranial left lung lobe torsion associated with

complete consolidation of the caudal left lung lobe.

Adjuvant therapy

Six (43%) of 14 animals diagnosed with neoplasia were treated with adjuvant

chemotherapy. Protocols varied based on the histological diagnosis and clinician’s

preference. Of animals that received chemotherapy, four had pulmonary

adenocarcinoma, one had metastasis from a previously excised cutaneous myxoid soft

tissue sarcoma, and one had metastasis from a previously excised oral squamous cell

carcinoma.

Clinical Outcome

The MST for dogs was 156 days (range, 3-3839 days). The MST for cats was not

reached (mean=424 days).

No patients died or were euthanized intraoperatively or within the first 24 hours post

operatively. However, one dog (6%) and 2 cats (20%) died or were euthanized in the

first 2 weeks post-operatively and one cat was lost to follow-up during this time

frame.

13

314

315

316

317

318

319

320

321

322

323

324

325

326

327

328

329

330

331

332

333

334

335

336

337

338

DISCUSSION

This study provides further information on signalment, clinical signs, peri-operative

complications, underlying diagnosis, outcomes, and survival times of 17 dogs and 10

cats undergoing pneumonectomy. This procedure is technically feasible with a

relatively high overall incidence of complications, but a prolonged survival time.

Among the 14 cases of pneumonectomy previously described in the veterinary

literature,1-4 seven were treated for neoplasia. This ratio is consistent with the present

study, with 52% of the cases (14 cases) diagnosed with neoplasia, including 10 cases

of pulmonary adenocarcinoma.

Computed tomography was performed in only 56% of the cases. During the second

half of the study accrual period, the use of preoperative CT scans increased, with two-

thirds of cases having a preoperative CT after 2009 compared to one-third of cases

between 2004-2009. This difference is likely due to the increased availability of this

imaging modality and the recognition by veterinary surgeons that CT is extremely

useful in staging and surgical planning of lung disease. In our opinion, CT scan

should be used for surgical planning and staging in all cases where a lung lobectomy

or pneumonectomy is being considered. Sensitivity of CT for correctly assessing

tracheobronchial lymph nodes (TBLN) status was 83%, and specificity was 100% in a

recent retrospective clinical series.17 Ballegeer et al.18 also described a CT protocol

and some cut off values to better assess the TBLN.

Assessment of the complete lung field or TBLN may influence the surgical plan and

the willingness of the owner to proceed with surgery as cases with positive TBLN for

metastatic disease are associated with a shorter survival time.17,19,20

14

339

340

341

342

343

344

345

346

347

348

349

350

351

352

353

354

355

356

357

358

359

360

361

362

363

The TBLN were assessed in only 7 patients in the present study (cytologically in one

patient and histopathologically in 6 patients). Three groups of tracheobronchial lymph

nodes are located around the tracheal bifurcation and are usually the primary site of

lymphatic metastasis for pulmonary neoplasms.21 Surgical removal of the

tracheobronchial lymph nodes can be challenging because of their location at the

pulmonary hilus in close association with the heart and major neurovascular

structures. An unstable patient during the procedure may also preclude extirpation of

the lymph nodes. The current recommendation is to palpate them and to perform a

biopsy if enlarged.22 However, the principal authors of this study recommend biopsy

of the lymph nodes systematically as normal size lymph nodes can be positive.17,18, 23

Surprisingly, only half (47%) of the CT studies report described involvement of the

entire left or right lung. Involvement of more than one lung lobe was a good indicator

for pneumonectomy. Among the remaining cases, only 3 cases presented with a lesion

in close association with the hilus, a location that precluded a single lung lobectomy.

Four cases presented some adhesions that led to the need for a pneumonectomy. In

these cases, CT was not very accurate for detection of adhesions and pneumonectomy

was not planned based on CT. It is important to consider pneumonectomy as a

potential procedure for complicated lung lobectomy or very extensive disease.

Pulmonary lymphatics

15

364

365

366

367

368

369

370

371

372

373

374

375

376

377

378

379

380

381

382

383

384

385

drain into 3 groups of tracheobronchial lymph nodes (TBLN)located around the tracheal bifurcation,1

16

386

387

388

389

390

391

392

393

394

and are the primarysite of lymphatic metastasis for pulmonary neoplasms.Assessment of TBLN for metastatic disease is an important

17

395

396

397

398

399

400

401

402

403

404

predictor of outcome in dogs with primary bronchoalveolarcarcinoma ,2–4

but TB LN are very challenging to access for

18

405

406

407

408

409

410

411

412

413

percutaneous preoperative fine needle aspiration or biopsybecause of their location at the pulmonary hilus, dorsal to theheart, and intimately

19

414

415

416

417

418

419

420

421

422

423

associated wi th major neurovascul arstructures. Because of this, it is currently recommended thatwhen lung tumor excision is

20

424

425

426

427

428

429

430

431

432

433

performed, as part of the surgicalprocedure TBLN should be palpated and biopsied if enlargedAn intercostal approach between the 4th and 6th ribs was the most common approach

for pneumonectomy in the present series. This approach allows for good exposure to

the hilus and direct access to the TBLN. Hemostasis and pneumostasis were achieved

with a stapling device in more than half of the cases. Use of stapler is associated with

rapid application and minimal complications24,25 and it is now, in the authors opinion,

the preferred technique used for lung lobectomy/pneumonectomy. For one case,

21

434

435

436

437

438

439

440

441

442

443

444

445

446

447

hemoclips were used for hemostasis and pneumostasis. This surgical technique is not

described for pneumostasis and is usually not recommended for hemostasis of large

vessels because of the risks associated with loosening of the hemoclips.26 However,

this cat did not present any peri or post-operative complications.

In this study, complications occurred in 76% and 80% of dogs and cats, respectively.

The incidences of major complications were 41% and 50% for dogs and cats,

respectively. No patients died or were euthanized intraoperatively or within the first

24 hours post operatively. However, one dog (6%) and two cats (20%) died or were

euthanized in the first 2 weeks post-operatively. In humans, pneumonectomy is also

associated with high morbidity. In a recent study reporting 5975 human patients,

complications were reported in 53% of patients with benign disease and 39% of

patients with neoplastic disease.13 In that study, the postoperative in-hospital mortality

rates were 22.1% and 5.1% for patients with benign and malignant disease,

respectively.13 Considering these high morbidity and mortality rates, this type of

surgical procedure is considered a salvage procedure in humans.13 The incidence of

complications in this study were similarly high: the surgical team and the owners need

to be prepared for these potential life threatening complications that will prolong

hospitalization and increase costs.

Complications in respiratory, cardiac and gastrointestinal function are the reported

complications associated with pneumonectomy in small animals.2,3 In the present

study, respiratory complications (persistent pleural effusion, oxygen dependence,

persistent increased respiratory rate or coughing) were the most commonly reported

complications. Gastrointestinal complications were uncommon and self-limiting: 4

22

448

449

450

451

452

453

454

455

456

457

458

459

460

461

462

463

464

465

466

467

468

469

470

471

472

cases (2/17 dogs and 2/10 cats) presented some regurgitation/vomiting and one case

(one cat) with diarrhea. The duration of the clinical signs was short (24-48 hours).

Previously reported by Liptak et al.2 as a potential complication, esophageal

dysmotility was not reported in this study.

Atrial fibrillation and varying degrees of atrioventricular (AV) block are common

cardiac complications following lung lobectomy or pneumonectomy3. In the study

performed by Kocaturk et al.3, one dog died within 7 days of pneumonectomy due to

complete AV block. Based on these findings, Kocaturk et al recommended pre and

postoperative cardiac evaluation of dogs undergoing lung resection. In the present

study, only one case presented a second-degree AV block (one dog) within 24 hours

after surgery.

In humans, numerous negative prognostic factors have been reported after

pneumonectomy: age greater than 65 years, underweight body mass index category,

American Society of Anesthesiologists score of 3 or greater, right laterality of the

procedure, performance of an extended pneumonectomy, or absence of systematic

lymphadenectomy.14 Despite being the largest study reporting clinical outcome after

pneumonectomy in the veterinary literature, the low numbers reported here precluded

significant statistical analysis and determination of prognostic factors.

Right pneumonectomy was not associated with a high mortality rate in this study.

This is clinically important because the current veterinary literature suggests that

right-sided pneumonectomy is not recommended due to the risk of fatal pulmonary

hypertension6 even if this procedure was successful for few patients.2,3 Likely the

reason that right-sided pneumonectomy was well-tolerated in these clinical patients

23

473

474

475

476

477

478

479

480

481

482

483

484

485

486

487

488

489

490

491

492

493

494

495

496

compared to reports in clinically normal dogs is that these patients had significant

disease in the affected lung and this likely led to a period of accommodation in these

patients, allowing them to tolerate right or left sided pneumonectomy. Pulmonary

hypertension and the inability to adjust to right-sided pneumonectomy remains a

potential complication of a pneumonectomy. However, this procedure should be

considered in affected patients, regardless of the side affected.

Limitations

Limitations of our study include the retrospective nature of the data collection, and

variations in surgical technique, tumor staging, perioperative management, and

postoperative follow-up routines between institutions. The physiologic impact of the

pneumonectomy on the lung or heart function was not assessed: spirometric analysis

of ventilatory function or echocardiography was not performed before or after

surgery. These tests may help to anticipate the complications3, the outcome or to

identify a potential risk factor. The limited numbers of patients also precluded more

advanced statistical analysis.

Conclusion

Pneumonectomy is an uncommon procedure, which is most commonly executed via a

lateral thoracotomy, using a TA stapling device. The incidence of complications is

relatively high for this procedure, but risk factors were not identified. Right-sided

pneumonectomy was not associated with a high mortality rate and side affected

should not influence the decision whether or not to perform this procedure in patients

with extensive disease requiring pneumonectomy.

ACKNOWLEDGMENTS

24

497

498

499

500

501

502

503

504505506

507

508

509

510

511

512

513

514

515

516

517

518

519

520

521

522

We thank Veterinary Society of Surgical Oncology (VSSO) members support for this

study and especially Drs. Julius Liptak, Michelle Oblak, David Dycus, Stan Veytsman

and Mirae Wood for case submission.

REFERENCES

25

523

524

525

526

527

528

529

530

531

532

533

534

535

536

537

538

539

540

541

542

543

544

545

546

547

1. Madewell, B. R., Nyland, T. G. and Weigel, J. E: Regression of hypertrophic osteopathy following pneumonectomy in a dog. Journal of the American Veterinary Medical Association 1978;172:818-821

2. Liptak JM, Monnet E, Dernell WS, et al: Pneumonectomy: four case studies and a comparative review. J Small Anim Pract. 2004;45:441-447

3. Kocatürk M, Salci H, Yilmaz Z, et al: Pre- and post-operative cardiac evaluation of dogs undergoing lobectomy and pneumonectomy. J. Vet. Sci. 2010; 11:257-264

4. Anagnostou TL, Pavlidou K, Savvas I, et al: Anesthesia and Perioperative Management of a Pneumonectomized Dog. J Am Anim Hosp Assoc. 2012 27;48:145-149

5. Nelson, AW: Lower respiratory system, in Textbook of Small Animal Surgery. (ed 2) Ed D. Slatter. W. B. Saunders, Philadelphia, 1993 pp 777- 804

6. Tobias KA, Johnston SA: Lungs, in Veterinary Surgery: Small Animal, 2012 (ed 1) pp1766-1768

7. Hsia CC, Carlin, JI, Cassidy SS, et al: Hemodynamic changes after pneumonectomy in the exercising foxhound. Journal of Applied Physiology. 1990 69, 51-57

8. Tronc, F, Grégoire, J, Leblanc P, et al: Physiologic consequences of pneumonectomy: consequences on the pulmonary function. Chest Surgery Clinics of North America. 1999; 9, 459-473

9. Davies P, McBride J, Murray GF, et al: Structural changes in the canine lung and pulmonary arteries after pneumonectomy. Journal of Applied Physiology. 1982;53, 859-864

10. Carlin, JI, Hsia CC, Cassidy SS, et al: Recruitment of lung diffusing capacity with exercise before and after pneumonectomy in dogs. Journal of Applied Physiology. 1991;70, 135-142

11. Hsia CC, Herazo LF, Fryder-Doffey F, et al: Compensatory lung growth occurs in adult dogs after right pneumonectomy. Journal of Clinical Investigation. 1994;94, 405-412

12. Nelson AW, Monnet E: Lungs, in: Textbook of Small Animal Surgery (ed 3) Ed D. Slatter. W. B. Saunders, Philadelphia. 2003 pp 880-889

13. Rivera C, Arame A, Pricopi C, Riquet M, Mangiameli G, Abdennadher M, et al. Pneumonectomy for benign disease: indications and postoperative outcomes, a nationwide studydagger. Eur J Cardiothorac Surg. 2014; 48(3):435-440

14. Stolz AJ, Harustiak T, Simonek J, et al: Pneumonectomy for non-small cell lung cancer: predictors of early mortality and morbidity. Acta Chir Belg. 2014;114(1):25-30

26

548549550551552553554555556

557558559560561562563564565566567568569570571572573574575576577

578579580

581582583

584585

586587588589

590591592

15. Thomas PA, Berbis J, Baste J-M, et al: Pneumonectomy for lung cancer: contemporary national early morbidity and mortality outcomes. The Journal of Thoracic and Cardiovascular Surgery. 2015;149(1):73–82

16. Groth SS, Burt BM, Sugarbaker DJ. Management of Complications After Pneumonectomy. Thorac Surg Clin. 2015;25(3):335-48

17. Paolini MC, Adams WM, Dubielzig RR, et al: Comparison of results of computed tomography and radiography with histopathologic findings in tracheobronchial lymph nodes in dogs with primary lung tumors: 14 cases (1999-2002). J Am Vet Med Assoc. 2006;228(11):1718–22

18. Ballegeer EA, Adams WM, Dubielzig RR, et al: Computed tomography characteristics of canine tracheobronchial lymph node metastasis. Vet Radiol Ultrasoun. 2010;22;51(4):397–40321.

19. McNiel EA, Ogilvie GK, Powers BE, et al: Evaluation of prognostic factors for dogs with primary lung tumors: 67 cases (1985-1992). J Am Vet Med Assoc. 1997;211(11):1422–7

20. Poulton GA, Brearley MJ, Powell SM, et al: Impact of primary tumor stage on survival in dogs with solitary lung tumors. J Small Anim Pract 2008;49:66–71

21.Evans HE, Howard E, DeLahunta A : The lymphatic system, in Miller’s anatomy of the dog (ed 4). Philadelphia, PA, Saunders, 2013, pp 545-550

22. Martano M, Boston S, Morello E, et al: Respiratory tract and thorax, in Kudnig ST, Seguin B, in Veterinary surgical oncology. Chichester, UK, Wiley Blackwell, 2012, pp 303

23. Langenbach A, McManus PM, Hendrick MJ, et al: Sensitivity and specificity of methods of assessing the regional lymph nodes for evidence of metastasis in dogs and cats with solid tumors. J Am Vet Med Assoc. 2001;218(9):1424–8

24. Hess JL: Use of mechanical staples in veterinary thoracic surgery. J Am Anim Hosp Assoc 1979;15:569

25. LaRue SM, Withrow SJ, Wykes PM: Lung resection using surgical staples in dogs and cats. Vet Surg 1987;16:238–240

26. Tobias KA, Johnston SA: Suture material, tissue staplers, ligations devices, and closure methods, in Veterinary Surgery: Small Animal, 2012 (ed 1) pp197

27

593594595596

597598599600601602603

604605606

607608609

610611612613614

615616617

618619620

621622

623624625626627

628

Case Breed Sex Weight(Kg)

Age at surgery

(Months)

Side affected

Approach Intra-operative and early complications

Diagnosis Outcome

1 Yorkshire Terrier FI 0.81 3 Left 4th ICSOxygen dependence

Anemia, anorexiaHypoglycemia, cardiac arrest

Diffuse pneumoniaCardiac arrest

(10 days)

2 WHWT MC 11.6 86 Left 5th ICS NoneBronchogenic pulmonary

adenocarcinomaEuthanasia (156 days)

3 Bernese mountain FS 25.4 100 Left Not recorded NoneBronchioalveolar

carcinomaEuthanasia(30 days)

4 Scottish Terrier FS 8.1 91 Left 5th ICS Infected pressure sores SCC (metastasis)Died

(33 days)

5 Weimaraner MC 52.4 108 Left 5th ICSPersistent pleural effusion

Incisional infectionPulmonary

adenocarcinomaEuthanasia(960 days)

6 Dachshund MC 8.6 24 Left 5th ICSHypothermia

Hypotension, coughingBronchogenic adenoma Alive

7 Labrador Retriever MC 34 132 Left 5th ICSSuspected immune mediated

vasculitisHigh grade STS

(metastasis)Euthanasia (87 days)

8 English Cocker MI 13 163 Left 5th ICSPersistent pleural effusion

CoughingBronchioalveolar

carcinomaEuthanasia(15 days)

9 Pug FS 9 77 Left 5th ICS None Lobe torsion Alive

10 Rottweiler FI 32.6 17 Right 5th ICS NoneChronic septic eosinophilic

bronchitis Alive

11 Mixed breed FS 22 148 Right 5th ICS Hemorrhage, AV blockPapillary pulmonary

adenocarcinomaAlive

12 Boxer MC 11.4 5 Left MS Hypotension, anemiaPrimary pleuritis,

pneumoniaUnknown

13 Golden Retriever FS 32 60 Left 4th ICS HypertensionPhlebitis, vomiting

Pleuropneumonia Alive

14 Mixed breed FS 23.1 144 Right 5th ICSHypothermia

Anorexia, tachycardiaChondrosarcoma

Died(54 days)

15 Mixed breed FS 33.3 164 Left 4th ICS Regurgitations Pulmonary CarcinomaDied

(96 days)

16 Springer Spaniel MC 18.1 54 Right MSCardiac arrest

Oxygen dependenceAnemia, increased RR

Chronic septic hemorragic pleuritis

Alive

17 Rottweiler mixed FS 26 62 Right 6th ICS None Pulmonary abscess Alive

28

629

Table 1: Breed, sexe (MC=male castrated, MI=male intact, FI=female intact,

FS=female spayed), weight, age at surgery, side of procedure, surgical approach

(ICS=intercostal space, MS=median sternotomy), intra-operative and early

complications encountered (RR=respiratory rate, AV=atrioventricular), final

diagnosis (SCC=squamous cell carcinoma, STS=soft tissue sarcoma) and outcome

(days represent time between surgery and death) of the 17 dogs.

29

630

631

632

633

634

635

Case Breed Sex Weight(Kg)

Age at surgery

(Months)

Side affected

Approach Intra-operative and early complications

Diagnosis Outcome

1 DSH MC 5.7 181 Left 6th ICSTension pneumothorax

HemorrhageAnemia

Papillary/Acinar Adenocarcinoma

Euthanasia(2 days)

2 DSH MC 2.2 6 Left MS Anemia Pulmonary abscess Unknown

3 DSH MC 6.5 84 Left 6th ICS None Pulmonary abscessAccidental death

(580 days)

4 Ragdoll FS 2.9 138 Right 5th ICS NonePulmonary adenocarcinoma

BronchopneumoniaDied

(345 days)

5 Main Coon MC 5.68 102 Right 5th ICSHemorrhage

AnorexiaDiarrhea

Pulmonary adenocarcinoma Unknown

6 DSH MC 3.8 12 Left MS Fever, Anemia Severe chronic pleuritis Unknown

7 DSH FS 3.3 161 Right 6th ICSHypotension

Ventilator dependentAnemia

Pulmonary adenocarcinomaEuthanasia

(1 day)

8 DSH MC 4.65 18 Right 6th ICSPersistent pleural

effusionIncreased RR

Pneumonia and pleuritis Alive

9 DSH FS 3.89 84 Left MSOxygen dependence

Hypotension, anemiaGranulomatous

bronchiopneumoniaAlive

10 Bengal MC 4.5 9 Right 5th ICS Anorexia, vomiting Bronchopneumonia Alive

30

636

Table 2: Breed (DSH=domestic short hair), sexe (MC=male castrated, MI=male

intact, FI=female intact, FS=female spayed), weight, age at surgery, side of

procedure, surgical approach (ICS=intercostal space, MD=median sternotomy), intra-

operative and early complications encountered (RR=respiratory rate), final diagnosis

and outcome (days represent time between surgery and death) of the 10 cats.

31

637

638

639

640

641

642

643