Anastomotic techniques for small intestinal obstruction in horses. A scoping review

BACKGROUND

Small bowel obstruction (SBO) is a significant cause of surgery in adult horses presenting with colic pain. SBOs often require resection and anastomosis. While various techniques for intestinal anastomoses have been developed, it remains uncertain if any fully meet our clinical needs.

OBJECTIVE

To conduct a scoping review of publications on anastomosis techniques and outcomes for the treatment of SBO.

STUDY DESIGN

Scoping review.

METHODS

A literature review was conducted using the CAB, Web of Science, Scopus, and PubMed databases. Peer-reviewed scientific articles in English, published between 1992 and 2023, were included. A quality assessment was performed for potentially eligible articles. Experimental studies, case reports, and case series with less than five cases were excluded and relevant data on study methods and sample size were extracted and charted from remaining articles. Anastomosis type and outcome were reported for articles considered potentially eligible for meta-analysis. Articles in which only overall outcome was reported or details on type of anastomosis were not reported were excluded for the final charting.

RESULTS

Of 3024 articles, 210 underwent a quality assessment. The most common study designs were case reports and case series (64.3%), followed by experimental studies (17.1%). After further exclusions, 104 articles met the inclusion criteria. In only 42 articles detailed data on type of anastomosis and relative outcome were reported. A total of 23 anastomosis types were reported for the treatment of SBO, with 6 different outcomes evaluated. Both short- and long-term survival rates consistently exceed 70% for all types of anastomosis (jejuno-jejunal, jejuno-ileal, and jejunocaecal).

MAIN LIMITATION

Non-English language studies and conference proceedings were excluded.

CONCLUSION

The body of literature focused on surgical treatment for SBO exhibits low-quality evidence. Several techniques of anastomosis were described for different pathologies. However, there is a lack of homogeneity in reporting outcome for each surgical technique. Furthermore, outcomes considered varied significantly among studies and were sometimes poorly reported, although success rates are generally high. Overall, there is a need for better-structured studies on existing and commonly used techniques before comparing techniques and exploring other innovative approaches.

Use of a new device for inversion of the necrotic ileal stump in the caecum in four horses

BACKGROUND

In jejunocaecal anastomosis leaving a necrotic ileal stump has been implicated in complications and poor outcomes. Elective inversion of the necrotic stump using a nasogastric tube has been previously described, although this procedure can be cumbersome and can cause caecocolic orifice occlusion.

OBJECTIVE

To describe the use of a new device for elective inversion of necrotic ileal stumps.

STUDY DESIGN

Case report.

METHODS

Details of the four horses that underwent intestinal resection and anastomosis with elective inversion of the ileal stump were retrieved from their medical records. For each case, a device was constructed by securing 0.7 m of hemp tape to a 0.5 m long electrical cable puller. The device was inserted into the ileum and passed through the caecum. The ileal lumen was closed using sutures or staples, and the tape was simultaneously secured to the intestine. The ileum was then resected. A small typhlotomy was performed at the proposed site for jejunocaecal anastomosis. The device was retrieved, the hemp tape was cut, and jejunocaecal anastomosis was completed.

RESULTS

The device was easily secured to the intestines. Small enterotomies were sufficient for device insertion and removal. In four clinical cases the procedure was effective in inverting the stump, and three out of the four horses recovered uneventfully and were discharged from the hospital. One horse was euthanised due to colic 27 months following discharge.

MAIN LIMITATIONS

Small number of cases admitted to single tertiary hospital.

CONCLUSIONS

The device was effective in inverting the ileal stump in the included clinical cases. By leaving a short, inverted stump, this method may help improve the prognosis for jejunocaecal anastomosis, possibly avoiding certain undesired effects of the procedure. Further studies with large numbers of cases are required.

Repeat Celiotomy-Current Status

Repeat celiotomy can be lifesaving in horses with a surgically treatable postoperative obstruction, although guidelines for its use are lacking, except for uncontrollable postoperative pain. Overdiagnosis of ileus as the cause of postoperative obstruction could delay a second surgery so the disease progresses beyond a manageable level of severity. Although many horses respond favorably to repeat celiotomy, complications can be severe and life threatening, such as incisional infection and adhesions. Repeat celiotomy does not seem to exacerbate postoperative ileus, despite additional surgical manipulation. An important benefit of repeat celiotomy is termination of hopeless cases, thereby reducing cost and suffering.

Ex vivo evaluation of a technique for equine jejunocecal anastomosis using radiofrequency thermofusion and a Cushing oversew

OBJECTIVE

To describe a technique for a side-to-side jejunocecal anastomosis in horses using radiofrequency thermofusion (TF) of the intestines supported by a Cushing oversew and to compare this anastomosis to handsewn and stapled techniques.

STUDY DESIGN

Ex vivo study.

SAMPLE POPULATION

Intestinal tracts from 24 slaughtered horses.

METHODS

A radiofrequency device was used to perform a jejunocecal anastomosis (Group RFA). The construction time and bursting pressure of this construct were compared with those of a hand-sewn double layer (Group HS) and stapled anastomoses (Group ST) without oversew of the staple line. Histology was also performed for the TF anastomoses to evaluate the extent of the thermal damage.

RESULTS

The median (range) construction time (min) for the TF (15.8 [14.4-16.8]) was not significantly different from that for the HS (25.5 [24.2-26.3]) and ST (10.8 [9.7-12.5]) groups (p = .07). The construction time for ST was shorter than that for HS group (p < .001). The average (standard deviation) bursting pressure (mmHg) for HS (153.1 +/- 17.5) was higher than that for RFA (76 +/- 15) and ST groups (48 +/- 13; p < .001). The bursting pressure of the RFA was higher than that of the ST anastomoses (p = .001). The thermal damage caused by the device was within the suture oversew in the deeper layers, whereas it extended a few mm beyond the suture line in the serosa.

CONCLUSION

Radiofrequency assisted anastomoses provide similar construction times to current techniques and have a higher bursting pressure than ST anastomoses.

CLINICAL SIGNIFICANCE

Radiofrequency-assisted anastomoses with a suture oversew demonstrated comparable bursting pressures to ST anastomoses. The use of the radiofrequency device on the intestine is extra label and causes serosal tissue damage, which may increase the risk of adhesions.

Effects of age, disease, and anastomosis on short- and long-term survival after surgical correction of small intestinal strangulating diseases in 89 horses

BACKGROUND

Although survival rates have been reported after small intestinal surgery for strangulating diseases in horses, none have followed survival for periods relevant to the long lifespan of horses and none have described effect of age, disease and surgical treatments over such long survival periods.

OBJECTIVES

To examine effects of age, disease, and type of surgery on long-term survival in horses after surgical treatment of small intestinal strangulating diseases over periods relevant to the expected lifespan of a horse.

STUDY DESIGN

Retrospective clinical study.

METHODS

Post-operative data were gathered from medical records and owner contact for 89 horses with small intestinal strangulation. Survival times from surgery to date of death or date of last follow-up were analysed by Kaplan-Meier statistics. Variables of interest were age, type of strangulating disease, and surgical correction. Cox proportional hazards regression was used to evaluate these variables.

RESULTS

Short-term survival was not affected by any of the variables measured. For long-term survival with Kaplan-Meier statistics, horses ≥16 years old had significantly shorter (P=0.002) median survival times (72 months; 95% C.I. 32.0-96.0) than younger horses (121.7 months; 95% C.I. 90.0-162), horses without resection had significantly longer (P=0.02) survival times (120 months; 95% C.I. 86-212) than horses that had jejunocecostomy (76.8 months; 95% C.I. 24-125), and horses with miscellaneous diseases had significantly longer (P=0.02) median survival times (161.9 months (95% C.I. 72.0-M) than horses with strangulating lipoma (79.8 months; 95% C.I. 32.0-120.0). In the multivariable Cox Proportional Hazard model, age (HR=2.67; 1.49-4.75, p<0.001) and anastomosis (HR=0.65; 0.46-0.92, P=0.02) had the most significant effect on median survival time.

MAIN LIMITATIONS

Limitations were small numbers in some categories, loss of cases to follow-up, owner recall failures, and lack of a control group.

CONCLUSIONS

The remaining lifespan of older horses at the time of surgery had the greatest effect on survival. Age could influence long-term survival studies after colic surgery, and therefore needs to be considered for survival analyses. Horses that did not require resection and anastomosis had favourable outcomes, underscoring the potential importance of early intervention to reduce the need for resection.

Is There Still a Place for Lidocaine in the (Postoperative) Management of Colics?

Intravenous lidocaine is widely used to prevent or treat postoperative ileus in horses. Clinical studies that support this approach are flawed and contradicted by others. Also, physical obstruction could be more important in causing postoperative reflux than postoperative ileus in the horse. The antiinflammatory properties of lidocaine and the role of inflammation from intestinal handling in the genesis of postoperative reflux are questionable. Because of cost and questionable efficacy of lidocaine, a well-designed clinical trial is required to support its continued use. However, lidocaine could be given to provide or enhance analgesia in selected cases with postoperative colic.

Exploratory Celiotomy in the Horse Secondary to Acute Colic: A Review of Indications and Success Rates

To review indications and risk factors for exploratory celiotomy secondary to acute colic in the horse; decision making for and during surgery; and prognosis for return to function after exploratory celiotomy for the practicing veterinarian. Data sources included scientific reviews and original research publications from veterinary sources, as well as clinical data specifically in regard to underlying disease and survival rates from a tertiary referral hospital where exploratory celiotomy is commonly performed. There is a high positive predictive value of specific clinical preoperative parameters of the equine acute abdomen, many of which rely on techniques available to field practitioners, relative to the need for surgical intervention. Decision making regarding surgical procedure or even intraoperative euthanasia depends on owner expectations. Survival rates following exploratory celiotomy range from fair to excellent (60%-100%) depending on underlying lesion and return to athleticism following celiotomy is good to excellent (76%-90%). A knowledge base of indications for and rates of survival from colic requiring exploratory celiotomy in the horse is of paramount importance to the equine practitioner. Preconceived notions of poor survival rates are rampant among horse owners, and owners rely on their primary veterinarian's advice for continuation to referral center and in further treatment including exploratory celiotomy.

Prevention of post operative complications following surgical treatment of equine colic: Current evidence

Changes in management of the surgical colic patient over the last 30 years have resulted in considerable improvement in post operative survival rates. However, post operative complications remain common and these impact negatively on horse welfare, probability of survival, return to previous use and the costs of treatment. Multiple studies have investigated risk factors for post operative complications following surgical management of colic and interventions that might be effective in reducing the likelihood of these occurring. The findings from these studies are frequently contradictory and the evidence for many interventions is lacking or inconclusive. This review discusses the current available evidence and identifies areas where further studies are necessary and factors that should be taken into consideration in study design.

In vitro description of a new technique for stapled side-to-side jejunocecal anastomosis in horses and CT scan anatomical comparison with other techniques

Background

Stapled jejunocecal anastomoses are commonly performed in equine abdominal surgery. They carry higher complication rates compared to handsewn techniques. In human surgery various causes likely to lead to failure of stapled techniques have been evaluated, including staple line failure. Recently Freeman proposed a technique to perform a stapled jejunocecal anastomosis in horses while avoiding blind pouch formation. The aim of this study is to describe a method for stapled side-to-side jejunocecal anastomosis in horses and to compare it with other techniques with computed tomography to assess stomal area, shape and blind pouch size.

Methods

Intestinal specimens comprising the cecum, ileum and jejunum from 18 horses were collected and were divided into three groups. In Group S a standard stapled side-to-side jejunocecal anastomosis was performed. In Group F the anastomosis was performed using a modified technique proposed by Freeman. In Group G the anastomosis was performed with a modified technique proposed by the authors. Inflated bowel segments were CT scanned to obtain a MultiPlanar Reconstruction of the stoma and afferent small intestine before calculating the cross-sectional area of each of these regions. The ratio of the measured areas was compared between the three techniques. The volume of the blind-end pouch was measured and its ratio with the intestinal area compared between techniques. The cecum was opened and the length of the stoma measured with a caliper and compared to the intended initial length.

Results

The stomal/intestinal area ratio was not significantly different between techniques.

No statistically significant difference was found in the stomal ideal/real perimeter ratio.

There was no statistically significant difference in the intended/real stomal length ratio, and all techniques featured an increase in stomal length ranging from 2 to 12 %. Blind pouch formation was a consistent finding in Group S and was virtually absent in Groups F and G.

Conclusions

Both the Freeman and the new (G) technique were comparable to the standard technique in terms of stomal area, stomal shape and difference in stomal elongation. They consistently produced a smaller blind pouch and allowed easier placement of the staplers.

Effects of staple size, tissue thickness, and precompression time on staple shape in side-to-side jejunocecal anastomosis in specimens obtained from healthy horses at an abattoir

OBJECTIVE

To determine effects of staple size, precompression time, and tissue thickness on staple shape and tissue approximation in side-to-side jejunocecal anastomosis in equine specimens.

SAMPLE

Cecum, ileum, and jejunum specimens obtained from 18 healthy horses at an abattoir.

PROCEDURES

Specimens were allotted into 2 groups. Anastomoses were stapled with 4.8-or 3.8-mm staples. Precompression time was 15 seconds for both groups. Staple lines were cut into proximal, middle, and distal sections. Thickness of intestinal walls was measured with a calibrated tissue micrometer, photographs were obtained, and intestinal tissues were digested. An investigator measured staples and assessed the shape of staples on high-definition digital images. Number of optimally shaped staples and staple height were compared among sections and between groups.

RESULTS

Use of 4.8-mm staples resulted in poor approximation of tissues in the distal sections of anastomoses. The percentage of optimally shaped staples was 538 of 551 (97.6%) and 616 of 634 (97.2%) for 4.8- and 3.8-mm staples, respectively. The percentage of optimally shaped staples did not differ significantly between groups for the same sections. There was a lower percentage of optimally shaped staples in the distal sections than in the proximal and middle sections of each group. Mean staple height did not differ significantly among sections of each group.

CONCLUSIONS AND CLINICAL RELEVANCE

Use of 3.8-mm staples with an adequate precompression time for jejunocecal anastomosis in horses resulted in proper staple shape. These findings could be used to improve the technique and outcome for stapled jejunocecal anastomoses in horses.

Long-term survival in horses with strangulating obstruction of the small intestine managed without resection

REASONS FOR PERFORMING STUDY

Although many studies have described results after small intestinal resection and anastomosis in horses, few have described the outcome in horses with strangulating lesions managed without resection.

OBJECTIVES

To examine short- and long-term recoveries in horses with strangulated small intestine that was judged to be viable during surgery and not resected.

STUDY DESIGN

Retrospective analysis of case records.

METHODS

Data were reviewed from all cases (35 horses) with colic caused by small intestinal strangulation that underwent surgery between 1996 and 2011 at 2 university hospitals and that were managed without resection by 2 surgeons who used a clinical grading system to assess intestinal viability. Kaplan-Meier analyses were used to examine long-term survival.

RESULTS

Survival to discharge from the hospital was 100%, and post operative complications developed in 11 horses (31%). Three horses (8.6%) required repeat coeliotomy because of persistent pain with or without reflux, and they responded favourably to decompression of distended intestine. Ten horses died after discharge, and 12 were still alive at follow-up from 20 to 192 months after surgery. Information was available on 13 horses after discharge, but these were eventually lost to follow-up. Kaplan-Meier analyses yielded a median survival probability of 120 months.

CONCLUSIONS

A subjective method of assessing small intestinal viability in strangulated small intestine in horses, as used in this study, could reduce the need for resection and anastomosis, with the associated complications and costs. Also, the favourable post operative course in these horses provides strong evidence that early referral could avoid the need for resection and improve survival. The numbers of horses with the most severe changes that were not resected were too small to allow a conclusion that such segments should be left in place, and additional criteria might be needed to guide that decision in such cases.

Ex Vivo Anatomical Characterization of Handsewn or Stapled Jejunocecal Anastomosis in Horses by Computed Tomography Scan

The aim of this study is to compare handsewn and stapled jejunocecal anastomosis with different stomal lengths in terms of anatomical differences. Group 1 underwent a two-layer handsewn jejunocecal side-to-side anastomosis (HS); Group 2 received a stapled jejunocecal side-to-side anastomosis (GIA). Each group was divided into two subgroups (HS80 and HS100, GIA80 and GIA100). Specimens were inflated and CT scanned. The stomal/jejunal area ratio and blind end pouch volume/area were measured and compared. Effective length of the stoma was measured and compared with the initial length. Stomal/jejunal area ratio was 1.1 for both 80 techniques, 1.6 for the GIA100, and 1.9 for the HS100 technique. Both HS and GIA techniques produced a blind end pouch and exhibited a mean increase of the final stomal length ranging from 6 to 11% greater than the original stomal length. All techniques will exhibit a length increase of the final stomal length compared to the intended stomal length, with a consequent increase in stomal area. Stapled techniques consistently produced a large distal blind end pouch. Length of a jejunocecal anastomosis should be selected in accordance with the diameter of afferent jejunum, and the 80 mm stomal length could be deemed sufficient in horses.