Introduction

Mesenteric volvulus is a rare condition in small animals that occurs when the intestines twist around the root of the mesentery. Many risk factors have been identified, including breed predisposition, enteritis, gastrointestinal foreign body, exercise regimen, recent gastrointestinal surgery, gastric dilatation and volvulus (GDV), trauma, intussusception, exocrine pancreatic insufficiency, and more.^1–4 When the cranial mesenteric artery is obstructed in cases of mesenteric volvulus, the gastrointestinal tract extending from the distal duodenum to the proximal descending colon undergoes ischemic necrosis, which leads to systemic shock, endotoxemia, circulatory collapse, and ultimately death if left untreated.^2,5–7 Prognosis for mesenteric volvulus is typically grave, with mortality rates ranging from 58% to 100%.^2,7–9 German Shepherd Dogs (GSDs) are an overrepresented breed developing mesenteric volvulus.^2,9

In a recent study by Andrews et al,¹⁰ prior prophylactic gastropexy was identified as a risk factor for military working dogs (MWDs) that were diagnosed with mesenteric volvulus. Prophylactic gastropexy procedures are used to decrease the likelihood of developing GDV, which is a life-threatening surgical emergency commonly diagnosed in large-breed dogs.^11–14 Following a gastropexy, recurrence rates of gastric dilatation with or without volvulus range between 6% and 10%, whereas patients in which a gastropexy was not performed have a recurrence rate over 50%.^15–18 Recent studies^14,18–21 report a mortality rate for GDV as high as 26.8%. The detrimental and potentially life-threatening sequelae of GDV have sparked a trend toward prophylactic gastropexy, especially for working dogs. The GSD is one of the most common breeds employed by the New York Police Department (NYPD), composing over 75% of the NYPD Transit police working dog (PWD) population in 2021 (Lieutenant John Pappas, Transit K9 unit Commander, email, September 2021). Purchase and subsequent training of these working dogs require a significant financial and time investment. Complete training of these working dogs may cost approximately $90,000 to $160,000 and take up to 4 to 6 months depending on their specific training (Lieutenant John Pappas, Transit K9 unit Commander, email, September 2021). The Animal Medical Center has worked with the NYPD to implement prophylactic gastropexy procedures for their canine officers once their training has been satisfactorily completed. Before this implementation, the NYPD Transit canine unit averaged approximately 1 case of GDV/y (Lieutenant John Pappas, Transit K9 unit Commander, email, September 2021).

To the authors’ knowledge, direct comparisons of the association of mesenteric volvulus in relation to gastropexy status have not been previously reported in PWDs, as their work and temperament may be different from those of MWDs. The objective of this study was to determine whether police dogs that had a laparoscopic prophylactic gastropexy were at increased risk for mesenteric volvulus. We hypothesized that there would be no difference in frequency of mesenteric volvulus when comparing police dogs with and without a prior prophylactic laparoscopic gastropexy performed.

Methods

Results

Records of 3 dogs affected with MV and 367 control dogs without MV were evaluated. All 3 MV case dogs were male GSDs without a reported history of aggressive behavior or steroid or NSAID usage (Tables 1 and 2). Two PWDs with MV were euthanized intraoperatively. The third was euthanized 4 days postoperatively due to progressive clinical decline. This patient that was euthanized postoperatively did not have a resection and anastomosis performed due to improved coloration, palpable arterial pulses, and suspected viability of the intestines following derotation. All 3 case dogs had the MV diagnosis confirmed intraoperatively.

Of the 370 dogs included in this study, the majority were GSDs (51.6%), although the study also included, in order of decreasing frequency, Labrador Retrievers, Belgian Malinois, mixed-breed dogs, Dutch Shepherds, German Shorthaired Pointers, and Bloodhounds (Table 3).

A history of prophylactic gastropexy was associated with increased odds of developing MV, and the GSD appeared overrepresented. Of the 82 PWDs that had undergone prophylactic laparoscopic gastropexy, 2 (2.4%) developed MV, whereas 1 (0.3%) of the 288 PWDs that had not undergone a gastropexy procedure developed MV (OR, 7.18; 95% CI 0.642 to 80.143). In PWDs undergoing a prophylactic laparoscopic gastropexy, the odds of developing MV were 7.2 times the odds of dogs without a gastropexy developing MV.

Discussion

This study reviewed medical records using a case-control design and analysis, including and evaluating every PWD medical record that was examined at the Animal Medical Center. Previously reported risk factors for MV include older age, GSD breed, historic gastrointestinal disease, gastropexy, and abdominal surgery.^4,8,10,22 In this study, all MV case dogs were GSDs, which correlates with previous studies, though, interestingly, patient ages ranged from 1.3 to 9 years old (median age, 6.7 years), whereas previous studies report the disease process being more common in an older patient population.^8–10,22 Only 1 case dog had a history of gastrointestinal surgery, including a jejunal enterotomy for a foreign body removal, performed 5 years before MV (Table 4); this patient’s laparoscopic gastropexy was performed 1 year before MV. Another case dog had a history of a perineal hernia repair and Lyme disease. This patient’s laparoscopic gastropexy was performed 1 year before perineal hernia repair, whereas MV occurred 2 years after the prophylactic laparoscopic gastropexy. In contrast, the third case dog did not have any pertinent surgical or medical history and was also the only case dog without a historic prophylactic laparoscopic gastropexy. Two of the case dogs worked with NYPD Transit, whereas the other worked with the NYPD Emergency Service Unit K9 Unit (Table 5).

In a previous study performed by Andrews et al,¹⁰ MV was more likely to develop in MWDs with a history of a prophylactic gastropexy. After a prophylactic gastropexy policy was implemented with the MWDs, GDV cases decreased, whereas a subjective increase in MV cases was noted.¹⁰ Our hypothesis was rejected, as there was a difference in frequency of mesenteric volvulus when comparing police dogs with and without a prior prophylactic laparoscopic gastropexy performed. In the present study, PWDs with history of prophylactic laparoscopic gastropexy were associated with increased odds of developing MV (OR, 7.2), though this was not determined to be statistically significant (1-sided P = .055). All case dog gastropexy sites were confirmed to be intact and in an appropriate position intraoperatively.

The correlation between gastropexies potentially predisposing to mesenteric volvulus remains unclear. Theories have been reported, including gastropexy sites altering physiologic gastrointestinal motility, though this was disproven in a recent study²³ where gastric motility was evaluated before and after gastropexy. Abdominal surgery has also been implicated in causing adhesions and transient ileus.²⁴ In the case dog population studied in the present report, no adhesions were noted intraoperatively that could have potentially contributed to MV formation. As MV occurred in GSDs only, which is a known risk factor for MV, the authors postulate that these patients may have been predisposed to MV regardless of their gastropexy status.

The major limitation of this study is its retrospective nature, its risk of type II error given the low incidence of MV occurrence, and, therefore, its low statistical power. This small sample size limits the statistical power of the analysis, making it difficult to detect significant associations or draw robust conclusions. The NYPD PWD population may also not be representative of other populations of PWDs or other dogs with MV. Another limitation is the fact that there were only 3 case dogs with MV over a 10-year time period, so all PWD medical records were included and used for data collection. This means that all PWDs evaluated at the Animal Medical Center were included and highlights the fact that mesenteric volvulus is a very rare disease process. In comparison, 137 GDVs were diagnosed at the Animal Medical Center compared to a total of only 14 MV cases during the study time period. Therefore, the occurrence of PWDs presenting with GDV is more than that of MV in this sample. This included the entire canine caseload seen at the AMC, including the 3 case dogs from our PWD group. These case numbers were confirmed via radiographic diagnosis via a board-certified radiologist and assessment of medical records.

In conclusion, analysis of this study’s data indicated that in PWDs with a prophylactic laparoscopic gastropexy, the odds of developing MV were 7.2 times the odds of dogs without a gastropexy developing MV. However, this result did not achieve statistical significance; thus, pooled statistical analysis of multiple studies evaluating for this association, meta-analysis, or other large cohort studies are needed to evaluate whether the association found in this study can be replicated or increased in precision. All case dogs with MV were GSDs, which corroborates previous reports^8–10,22 for this breed predisposition. Based on the findings of this study, it is important to be aware of the fact that the potential likelihood of developing MV appears increased when a prophylactic gastropexy is performed. Despite this finding, the authors still strongly recommend prophylactic gastropexy due to the increased frequency of GDV compared to MV.

Disclosures

The authors have nothing to disclose. No AI-assisted technologies were used in the generation of this manuscript.

Funding

The authors have nothing to disclose.