Surgeries to remove gastrointestinal foreign bodies are often performed in dogs. Although most dogs tend to do well after surgery, serious complications can occur. Dehiscence of full-thickness intestinal incisions and subsequent leakage of intestinal contents into the abdomen can result in septic peritonitis. The overall rate of dehiscence following full-thickness intestinal incisions in dogs was reported to be between 12% and 15.7% in studies1–3 that evaluated dehiscence rates for enterectomy and enterotomy procedures combined and that included multiple indications for surgery (foreign body removal, trauma, and neoplasia). However, current literature does not accurately report the dehiscence rate following enterotomy for foreign body removal alone.
Surgical removal of intestinal foreign bodies is generally accomplished with enterotomy or enterectomy, and the surgeon selects the specific procedure on the basis of an assessment of intestinal ability to recover from ischemic insult.4 Resection and anastomosis is preferred for removal of intestinal foreign bodies associated with substantial ischemic trauma and intestinal compromise. When an enterectomy is required, the affected intestines have presumably undergone more ischemic trauma and compromise, compared with intestines that can be treated with an enterotomy; therefore, the rate of dehiscence following enterectomy may be higher than that following enterotomy. Further, technical difficulty of enterectomy with anastomosis is greater than that of enterotomy, possibly contributing to a higher rate of dehiscence following enterectomy. Previous studies1,2,5 have revealed that the presence of intestinal foreign bodies increases the risk for intestinal dehiscence following surgery; however, to our knowledge, there is no published rate of dehiscence following foreign body removal by enterotomy in a large population of dogs.
The purpose of the study reported here was to determine the intestinal incisional dehiscence rate following enterotomy for foreign body removal in dogs. Knowledge of risks of intestinal incisional dehiscence for specific conditions could guide expectations for prognosis and help to establish standards of care in veterinary surgery. We hypothesized that the rate of intestinal incisional dehiscence following enterotomy for intestinal foreign body removal was less than the reported 12% to 15.7%.1–3 A secondary goal was to investigate previously identified factors (eg, hypoproteinemia [< 5.0 g/dL], hypoalbuminemia [< 2.5 g/dL], and the presence of preoperative septic peritonitis) associated with increased rates of enterotomy dehiscence.1–3,5,6
Materials and Methods
Animals
Medical records were searched for dogs that underwent enterotomy for removal of intestinal foreign bodies between November 2001 and September 2017 at veterinary institution 1 and between June 2005 and September 2017 at veterinary institution 2. Criteria for inclusion were dogs of any age undergoing enterotomy, multiple enterotomies, or enterotomy with concurrent gastrotomy to remove ≥ 1 foreign body from the small intestine. Dogs that underwent enterectomy, were euthanized, or died intraoperatively were excluded from the study. Dogs were grouped according to whether intestinal incisional dehiscence occurred (dehiscence group) or did not occur (nondehiscence group) following enterotomy.
Data collection
Data collected from the medical records were assigned to preoperative, intraoperative, or postoperative time periods. Preoperative data included signalment, body weight, body condition score (on a scale from 1 to 9), previous gastrointestinal surgery, previous or current treatment with NSAIDs or corticosteroids, reported comorbidities (eg, endocrinopathies or neoplasia), and, when available, results from preoperative clinicopathologic evaluations. Preoperative clinicopathologic data collected included plasma concentrations of lactate and total protein, serum albumin concentration, and the presence (yes or no) of hypoproteinemia2 (< 5.0 g/dL), hypoalbuminemia (< 2.5 g/dL), or anemia (PCV < 35%), alone or in combination.
Intraoperative data collected included date and duration of the surgical procedure, whether the surgery was performed after hours (ie, between 5 pm and 8 am), total duration of surgery (ie, minutes from skin incision to completion of skin closure), total duration of general anesthesia (ie, minutes from intubation to extubation), frequency and duration of intraoperative hypotension (ie, mean arterial pressure of < 60 mm Hg and method of measurement), suture material and pattern used to perform enterotomy closure, type of foreign body (ie, linear vs nonlinear), whether concurrent gastrotomy was performed, any concurrent surgical procedures in the abdomen (eg, gastropexy or biopsies), intestinal segment incised (ie, duodenum, jejunum, or ileum), and any abnormal findings during the exploratory portion of the surgery. Surgeon experience was also recorded for each surgery. This included whether the primary surgeon was a faculty member or resident. In surgeries for which a resident was the primary surgeon, data collected also included the year of residency and whether a faculty member surgeon was present.
Postoperative data collected included the occurrence of intestinal incisional dehiscence, survival to hospital discharge, duration of hospitalization, treatment with NSAIDs or corticosteroids, date of last follow-up, and occurrence of any surgery-related complications (eg, incision site infection, gastroenteritis, or pancreatitis). When available, the same laboratory variables collected for the preoperative period were collected for the postoperative period from results obtained from the first clinicopathologic evaluations performed following surgery.
Preoperative septic peritonitis was considered to have been present in dogs with evidence in the medical record that the condition had been identified by intraoperative confirmation of gastrointestinal leakage. Diagnosis of postoperative intestinal incisional dehiscence was by cytologic evidence (ie, intracellular bacteria with degenerative neutrophils) combined with clinical deterioration consistent with septic peritonitis or by evidence of gastrointestinal leakage found on reoperation or necropsy. When intestinal incisional dehiscence was diagnosed, the date and means (ie, cytology and clinical signs, reoperation, or necropsy) were recorded.
Statistical analysis
Descriptive data were generated. Univariable analysis of all variables was performed to evaluate the strength and direction of association with intestinal incisional dehiscence. Categorical variables were evaluated with the Fisher exact test, and continuous variables were compared with the Wilcoxon rank sum test. Missing data were left as missing (ie, not imputed). Commercially available softwarea was used for all analyses, and values of P ≤ 0.05 were considered significant.
Results
A search of the medical records identified 247 client-owned dogs that underwent enterotomy for removal of intestinal foreign bodies between November 2001 and September 2017 at veterinary institution 1 and between June 2005 and September 2017 at veterinary institution 2. Overall, the mean ± SD age was 4.4 ± 3.2 years (range, 0.2 to 14 years), the median body weight was 22.2 kg (48.8 lb; range, 0.8 to 74.6 kg [1.76 to 164.1 lb]), and the median body condition score was 5 (range, 1 to 8). There were 90 castrated males, 53 sexually intact males, 93 spayed females, and 11 sexually intact females. The most common breeds represented were Labrador Retriever (n = 55), Dachshund (15), and German Shepherd Dog (10).
Five of the 247 (2.0%) dogs had intestinal incisional dehiscence (dehiscence group) following enterotomy, whereas 242 did not (nondehisence group). Diagnosis of dehiscence was based on findings on reoperation (n = 4) or on cytologic analysis of abdominal fluid combined with abdominal ultrasonography and clinical decline (1). The median age was 4.4 years (range, 0.2 to 14.0 years; n = 242) for dogs in the nondehisence group and 7.8 years (range, 5.0 to 12.0 years; 5) for dogs in the dehiscence group.
Eight of the 247 (3.2%) dogs had evidence of preoperative septic peritonitis noted in their medical records, and 7 (2.8%) had preoperative hypoproteinemia (< 5.0 g/dL; Table 1). In the 247 dogs, there were 267 intestinal incisions, including 200 (74.9%) jejunal incisions, 54 (20.2%) duodenal incisions, and 13 (4.9%) ileal incisions, alone or in combination (Table 2). The suture pattern used to close intestinal incisions was reported in the medical records of 243 dogs and included simple interrupted (146/243 [60.1%]), simple continuous (92/243 [37.9%]), and double layer continuous (baseball stitch; 5/243 [2.1%]).
Summary of key preoperative variables for 247 client-owned dogs undergoing enterotomy for intestinal foreign body removal at 1 of 2 veterinary institutions between November 2001 and September 2017 grouped according to whether intestinal incisional dehiscence occurred (dehiscence group; n = 5) or did not occur (nondehiscence group; 242).
| Variable | No. of dogs in the dehiscence group | No. (%) of dogs in the nondehiscence group | P value |
|---|---|---|---|
| Septic peritonitis | 0 | 8 (3.3) | 0.68 |
| Received NSAIDs or steroids | 1 | 11 (4.5) | 0.12 |
| Previous gastrointestinal surgeries | 1 | 18 (7.4) | 0.29 |
| Preexisting conditions | 2 | 27 (11.2) | 0.05 |
| Hypoproteinemia (< 5.0 g/dL) | 0 | 7 (2.9) | 0.69 |
| Hypoalbuminemia (< 2.5 g/dL)* | 0 | 12 (7.3)* | 0.53 |
| Anemia (PCV < 35%) | 0 | 5 (2.0) | 0.75 |
Information regarding serum albumin concentration was available in the medical records of 164 dogs in the nondehiscence group.
Summary of key intraoperative variables assessed in the dogs described in Table 1.
| Variable | No. of dogs in the dehiscence group | No. (%) of dogs in the nondehiscence group | P value |
|---|---|---|---|
| Suture pattern* | Â | Â | 0.37 |
|  Simple interrupted | 2 | 144 (60.5)* |  |
|  Simple continuous | 2 | 90 (37.8)* |  |
|  Double layer continuous | 1 | 4 (1.7)* |  |
| Suture type†|  |  | 0.81 |
|  Polydioxanone | 5 | 217 (92.7)†|  |
|  Poliglecaprone 25 | 0 | 17 (7.3)†|  |
| Location of incision‡ |  |  | 0.47 |
|  Duodenum | 3 | 51 (21.1) |  |
|  Jejunum | 2 | 198 (81.8) |  |
|  Ileum | 1 | 12 (5.0) |  |
| Foreign body | Â | Â | 0.33 |
|  Linear | 3 | 87 (36.0) |  |
|  Nonlinear | 2 | 155 (64.1) |  |
| Timing of surgery | Â | Â | 0.49 |
|  After-hours surgery | 2 | 141 (58.3) |  |
|  During business hours | 3 | 101 (41.7) |  |
| Faculty surgeon participated§ | 1§ | 92 (39.3)§ | 0.38 |
| Gastrotomy also performed | 3 | 93 (38.4) | 0.32 |
| Underwent concurrent procedures | 3 | 78 (32.2) | 0.19 |
| Intraoperative hypotension (MAP < 60 mm Hg) | 2 | 59 (24.4) | 0.41 |
| Duration of anesthesia (min)‖ | 179 (105–260) | 156 (80–325) | 0.41 |
| Duration of surgery (min)‖ | 123 (84–162) | 95 (30–236) | 0.08 |
Reported in the medical records of only 238 dogs in the nondehiscence group
Reported in the medical records of only 234 dogs in the nondehiscence group
Some dogs had ≥ 1
Reported in the medical records of only 235 dogs
Reported as the median and range.
MAP = Mean arterial pressure.
In the 8 dogs with preoperative septic peritonitis, the intestinal perforations were surgically repaired with the edges of the perforated area minimally debrided (n = 7) and closed with a simple continuous suture pattern (3) or a simple interrupted suture pattern (4). The medical record of the remaining dog with septic peritonitis did not describe how the edges of the perforation were treated or the suture pattern used for closure. The intestinal perforations of these 8 dogs were located in the duodenum (n = 4) or jejunum (4). All 8 dogs with preoperative septic peritonitis were in the nondehiscence group and survived to hospital discharge. Survival to hospital discharge did not differ significantly (P = 0.77) between dogs with and without preoperative septic peritonitis.
Two of the 5 dogs in the dehiscence group did not to survive to hospital discharge: one dog died of complications of septic peritonitis (confirmed on reoperation and necropsy), and the other was euthanized per the owner's request because of the dog's poor prognosis after it developed septic peritonitis (diagnosed with cytologic evaluation). These dogs (2/247 [0.8%]) were the only dogs not to survive to hospital discharge (Table 3). Nonsurvival to hospital discharge was significantly (P < 0.001) more common for dogs in the dehiscence group (2/5) versus the nondehiscence group (0/242). In addition, median duration of hospitalization was significantly (P < 0.001) longer for dogs in the dehiscence group (8 days; range, 3 to 15 days) versus the nondehiscence group (4 days; range, 2 to 14 days).
Summary of key postoperative variables assessed for dogs described in Table 1.
| Variable | No. of dogs in the dehiscence group (n = 5) | No. (%) of dogs in the nondehiscence group (n = 242) | P value |
|---|---|---|---|
| Hypoproteinemia (< 5.0 g/dL)* | 3* | 21 (37.5)* | 0.34 |
| Hypoalbuminemia (< 2.5 g/dL)†| 3†| 18 (36.0)†| 0.29 |
| Received NSAIDs or corticosteroids | 0 | 11 (4.6) | 0.60 |
| Duration of hospitalization (d)‡ | 8 (3–15) | 4 (2–14) | < 0.001 |
| Did not survive to discharge | 2 | 0 | < 0.001 |
Concentration reported in the medical records of only 59 dogs
Concentration reported in the medical records of only 53 dogs
Reported as the median and range.
Overall, the mean ± SD duration of surgery was 95 ± 34.5 minutes (median, 90 minutes; range 30 to 236 minutes). The duration of surgery did not differ significantly (P = 0.08) between dogs in the dehiscence group (mean ± SD, 123 ± 28 minutes; median, 123 minutes; range, 84 to 162 minutes) and dogs in the nondehiscence group (mean ± SD, 95 ± 35 minutes; median, 95 minutes; range, 30 to 236 minutes). Similarly, the overall mean ± SD duration of anesthesia was 156 ± 45 minutes (median, 155 minutes; range, 60 to 325 minutes), and the duration of anesthesia did not differ significantly (P = 0.41) between dogs in the dehiscence group (mean ± SD, 179 ± 55 minutes; median, 179 minutes; range, 105 to 260 minutes) and dogs in the nondehiscence group (mean ± SD, 156 ± 44 minutes; median, 155; range, 80 to 325 minutes). Further, results identified no association between intestinal incisional dehiscence and other variables, including suture pattern, suture material, presence of pre- or postoperative hypoalbuminemia, presence of pre- or postoperative hypoproteinemia, linear versus nonlinear foreign body, number of intestinal incisions, location of intestinal incision, presence of preoperative plasma lactate concentration > 2.5 mmol/L, presence of preoperative band neutrophil count > 1,000 band neutrophil cells/μL, surgeon experience (resident vs faculty), enterotomy performed after hours (vs during business hours), presence of intraoperative hypotension, or whether additional procedures were performed during the same anesthetic event.
Discussion
Results of the present study indicated a dehiscence rate of 5 in 247 (2.0%) enterotomies performed in dogs for removal of intestinal foreign bodies. Therefore, we accepted our hypothesis that the rate of dehiscence following enterotomy for foreign body removal in dogs was less than previously reported rates (12% to 15.7%) in studies1–3 that included multiple surgical methods. However, enterectomies and enterotomies are difficult to interpret together because intestinal enterectomies may be more prone to dehiscence for multiple reasons. For instance, poor wound apposition is a risk factor for dehisence,7 and direct approximation of wound edges is more difficult to achieve in enterectomy than enterotomy owing in part to the circumferential nature of enterectomy and possible luminal disparity. Leakage at the enterectomy site is most likely to occur at the mesenteric border,1 a location not incised during enterotomy. Compared with enterotomies, enterectomies involve more technical difficulties, greater surgical duration, and larger amounts of suture material that may negatively influence tissue healing following surgery. Given that various factors may contribute to increased risk of dehiscence for intestinal enterectomies, the inclusion of patients undergoing enterectomy in previous studies1–3 likely explains their higher reported rates of dehiscence, compared with the lower rate indicated in the present study that excluded dogs undergoing enterectomy.
Results of previous studies2,5 disagree on how surgical indication may influence the rate of dehiscence. For instance, one study2 shows that the presence of a foreign body is a protective factor for dehiscence, whereas a different study5 shows that when an enterectomy is performed for foreign body removal, dehiscence is more likely to occur than when performed for other indications. Therefore, the 2.0% dehiscence rate following enterotomy for removal of intestinal foreign bodies from dogs of the present study may not be applicable to other indications for enterotomy or for intestinal biopsy.
Interestingly, 8 dogs in the present study had preoperative septic peritonitis, and none developed intestinal incisional dehiscence. This finding indicated that preoperative septic peritonitis was not associated with postoperative intestinal dehiscence in dogs of the present study. However, several previous studies1–3,5–8 identify reported septic peritonitis as a risk factor for intestinal dehiscence. The lack of association in our study may have been attributable to a type II error or selection bias, alone or in combination. In our experience, it is unlikely for a dog with septic peritonitis to undergo enterotomy without enterectomy, and because dogs requiring enterectomy were excluded from our study, few dogs with preoperative septic peritonitis were included. Further, the 8 dogs with septic peritonitis may have had less severe or more focal peritonitis or had different unknown factors that contributed to the surgical decision to repair perforations by enterotomy rather than by enterectomy.
Compared with resection of perforated intestinal tissue, repair of perforations without resection is in our opinion relatively uncommon in veterinary surgery. However, perforations in the proximal aspect of the duodenum may be difficult to resect owing to the complicated anatomic structures in that location. Eight dogs had intestinal perforations repaired in the present study. In some of the affected dogs, perforation repair rather than resection may have been elected as a superior option to biliary rerouting, which is associated with relatively high morbidity and mortality rates and can result in long-term complications that may not be tolerated by some owners.9 Because of the retrospective nature of the present study, reasons for performing repair of an intestinal perforation rather than resection were unknown. However, the fact that all dogs with intestinal perforations repaired with enterotomy survived to hospital discharge suggested that primary repair of intestinal perforations may be a reasonable option in some dogs.
No risk factors for intestinal incisional dehiscence were identified in the present study. This may have been because of the low power of the study. Logistic regression was not performed because of the small number of dogs in the dehiscence group.
Overall, dogs in the dehiscence group had longer duration of hospitalization than did dogs in the nondehiscence group. This finding was expected because treatment for septic peritonitis generally requires additional surgery and intensive management and because the mortality rate for dogs with septic peritonitis has been reported as 37% to 74%.1,5,7,10 Consistent with those previously reported rates, 2 of the 5 dogs with postoperative septic peritonitis secondary to intestinal incisional dehiscence did not survive to hospital discharge.
Although, to our knowledge, the present study encompassed the largest reported number of dogs undergoing enterotomy for intestinal foreign body removal, a limitation was that of the 251 dogs that underwent enterotomy, only 5 subsequently developed intestinal dehiscence; therefore, it was not possible to identify risk factors associated with dehiscence in dogs of the present study. A case-control study evaluating perioperative factors and their effects on intestinal dehiscence rates in dogs undergoing enterotomy for foreign body removal may be valuable.
An additional limitation was the method used to diagnose septic peritonitis. In 1 of the 5 dogs in the dehiscence group, postoperative septic peritonitis was diagnosed on the basis of results from cytologic analysis, clinical deterioration, and ultrasonography. Although dehiscence was most likely, it was possible that this dog had a gastrointestinal perforation instead.
Results of the present study indicated that the intestinal dehiscence rate following enterotomy was low; however, the low rate should not be used as a reason to perform an enterotomy rather than an enterectomy when needed. The low dehiscence rate likely indicated that the appropriate surgery was selected for the dogs of the present study and could have reflected differences in other factors (eg, tissue viability and preoperative septic peritonitis) rather than a fundamental difference between techniques alone. Surgeons should thoroughly evaluate the bowel and perform an enterotomy only when indicated.
Acknowledgments
No third-party funding or support was received in connection with the present study or the writing or publication of the manuscript. The authors declare that there were no conflicts of interest.
Footnotes
SAS, version 9.3, SAS Institute Inc, Cary, NC.
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