Clinical Evaluation of a Right-Sided Prophylactic Gastropexy Via a Grid Approach
A new technique is described for a prophylactic incisional gastropexy via a right-sided grid approach (i.e., minilaparotomy). A pilot study showed comparable tensile strength between a traditional ventral midline approach and the grid approach. Six client-owned dogs were selected for the procedure. Four weeks postoperatively, a barium gastrogram was performed to assess stomach/gastropexy position. Complications included a seroma and postoperative discomfort. This technique should be considered for any at-risk breed that is not overweight. The right-sided grid approach to a prophylactic gastropexy was less invasive than a ventral midline approach and resulted in a stable gastropexy at 4 weeks postoperatively in five of six dogs.
Introduction
Gastric dilatation-volvulus (GDV) is a life-threatening disease that affects approximately 60,000 dogs annually—mostly large and giant, deep-chested breeds—with reported mortality rates between 10% and 60%.1 At the time of surgical treatment for GDV, a right-sided gastropexy should be performed to prevent recurrence.1 In dogs at risk for developing GDV, this prevalent and serious disease could be prevented with a prophylactic right-sided gastropexy. Prophylactic gastropexies have been rarely discussed in the literature; most studies have examined different gastropexy techniques in preventing the recurrence of GDV. A prophylactic right-sided gastropexy through a muscle-separating grid approach (i.e., minilaparotomy) would provide a less invasive surgery with minimal morbidity and postoperative complications.23
A pilot study was performed to compare the maximum tensile strength to failure of incisional gastropexies performed by two different surgical approaches in cadavers. The authors’ hypothesis was that the grid approach for a prophylactic right-sided gastropexy would be faster to perform and result in a gastropexy with a maximal tensile strength comparable to one performed via a ventral midline approach. The developed technique was then evaluated in six clinical cases. The authors’ goal was to develop an effective prophylactic surgical procedure for GDV that is quick and easy to perform, using instrumentation readily available to the general veterinary practitioner.
Materials and Methods
Pilot Cadaver Study
Twenty-four, mixed-breed, adult, medium- to large-breed dogs euthanized via an injection of barbiturate for other reasons were included in this terminal study. The cadavers were collected on four occasions and randomly assigned to group A or B. In group A cadavers, a right-sided incisional gastropexy was performed via a standard ventral midline approach. In group B cadavers, an incisional gastropexy was performed via a right-sided grid approach. The same surgeon (Steelman-Szymeczek) performed all gastropexies. Upon completion of the surgical procedure, the stomach with the gastropexy site centered in an 8 × 8-cm section of the corresponding body wall without the skin was collected. This tissue was moistened with normal saline, wrapped in gauze sponges, and stored at −20°C. On the day before biomechanical testing was performed, the samples were removed from the freezer and allowed to thaw overnight in a refrigerator. Biomechanical testing was completed within 23 days on all specimens.
Ventral Midline Approach (Group A Cadavers)
Group A cadavers were placed in dorsal recumbency, and a ventral midline incision was made from the xiphoid caudally for 20 cm. Balfour retractorsa were used on the cut edges of the body wall incision. Babcock intestinal forcepsb were used to stabilize the pyloric antrum. A 3-cm longitudinal incision was made through the serosa and muscularis layers of the gastric antrum approximately 5 cm orad to the pylorus and equidistant between the attachments of the greater and lesser omentum. A second incision was made through the peritoneum and transversus abdominus muscle at the right ventrolateral body wall adjacent to the gastric antrum incision. This incision was perpendicular to the costal arch. Care was taken to ensure the stomach remained in a normal anatomical alignment. The dorsal aspect of the body wall (i.e., the transversus abdominus fascia and muscle) incision was sutured to the dorsal aspect of the gastric antrum incision in a simple continuous pattern with 2-0 monofilament nylon.c The ventral aspect of the body wall incision was sutured to the ventral aspect of the gastric antrum incision in a simple continuous pattern with 2-0 monofilament nylon.c The ventral midline incision was closed with 0 polyglyconated in a simple continuous pattern in the linea alba; 2-0 and 3-0 polyglyconated in a simple continuous pattern in the subcutaneous and subcuticular, respectively; and 3-0 nylonc in a cruciate pattern in the skin.
Minilaparotomy/Grid Approach (Group B Cadavers)
Group B cadavers were placed in left recumbency. A 6-cm vertical skin incision and a right-sided grid approach were made just caudal and ventral to the 13th rib [Figure 1]. The grid approach was accomplished by blunt dissection in the direction of the fibers of the external abdominal oblique, internal abdominal oblique, and transversus abdominus muscles [Figure 2]. The transversus abdominus muscle fibers run transversely so this gastropexy is oriented in that direction. The abdomen was entered via blunt dissection of the peritoneum to avoid damage to the underlying structures. If the stomach was not visualized, palpation of the duodenum and pylorus with two fingers was used, as needed, to locate the antrum of the stomach. Babcock intestinal forcepsb were used to grasp and retract the gastric antrum into the surgical field. The stomach was identified by palpation of the pylorus and visualization of the omental attachments, right gastric vessels, and right gastroepiploic vessels. Stay sutures were placed at each end of the intended gastric incision to hold the stomach in the surgical field [Figure 3]. At this point, the gastric antrum was allowed to fall back into the abdomen while the pylorus was again palpated to ensure proper placement of the gastric incision. A 3-cm longitudinal incision was made through the serosa and muscularis layers of the gastric antrum approximately 5 cm orad to the pylorus, equidistant between the attachments of the greater and lesser omentum. The dorsal edge of the gastric antrum and cranial edge of the transversus abdominus fascia and muscle were sutured in a simple continuous pattern with 2-0 monofilament nylon.c The ventral edge of the gastric antrum and caudal edge of the transversus abdominus fascia and muscle were also sutured in a simple continuous pattern with 2-0 nylonc [Figure 4]. The internal abdominal oblique, external abdominal oblique, and subcutaneous layers were each closed in a simple continuous pattern with 3-0 polyglyconate.d The skin was closed with 3-0 nylonc in a cruciate pattern.
Total surgical times were recorded as the time from skin incision to skin closure. For comparison of the individual gastropexy techniques, a separate time was recorded from the incision in the gastric antrum to the closure of the gastric antrum to the body wall.
Biomechanical Testing
Each section of tissue was connected to the materials testing machinee via a specially designed apparatus. The body wall was secured in the bottom clamps. The body wall was folded over a perforated metal plate. Two other perforated metal plates were placed on the outside edges of the body wall. These were secured in place by U plates and vise grips. The stomach was secured on an “L” arm placed through the gastric lumen. The gastric body was placed on the “L” arm followed by the pylorus. The maximal tensile strength was defined as the maximal load sustained by the gastropexy site before failure. The maximal tensile strength (tensile load to failure) was achieved by distraction of the stomach from the body wall at a rate of 20 mm per minute and was charted on a strip recorder at a chart speed of 50 mm per minute. Mode of failure was also recorded as stomach, body wall, or both, for each sample.
Statistical Analysis
The total surgery time, gastropexy time, and maximal tensile strength to failure were compared between groups A and B with an independent samples t-testf with a significance value set at P<0.05.
Clinical Case Study
Patient Selection
Small animal patients at the North Carolina State University Veterinary Teaching Hospital were considered for this procedure when they were at an increased risk for GDV because of signalment, body conformation, personality, or a littermate that developed GDV. The breeds included greyhound (n=2), Belgian Malinois (n=1), Labrador retriever (n=1), golden retriever (n=1), and Louisiana Catahoula leopard dog (n=1).
Surgical Approach
Animals were sedated with morphine (0.5 mg/kg body weight, intramuscularly [IM]) with or without acepromazine (0.025 mg/kg body weight, IM). A cephalic catheter was placed, and intravenous (IV) lactated Ringer’s solution was given at 10 mL/kg body weight. Anesthetic induction was achieved with IV propofol calculated at 5 mg/kg body weight but given to effect. Animals were intubated, and anesthesia was maintained with inhalational isoflurane in oxygen. The surgical protocol was followed as described above under Grid Approach (Group B). Total surgery and gastropexy times were recorded. The animals recovered from anesthesia uneventfully.
Barium Gastrogram
Four weeks after each surgery, a barium gastrogram was performed. Ventrodorsal and lateral survey radiographs were taken. Then an orogastric tube was placed to the level of the gastric cardia with fluoroscopic guidance. Fifty percent barium at approximately 7 to 13 mL/kg body weight was administered via the orogastric tube. Radiographs and fluoroscopy were used to evaluate the position of the gastric antrum in relationship to the body wall and gastric motility.
Results
Pilot Cadaver Study
The duration of the surgical procedure differed significantly between groups A and B. The mean and standard deviation (SD) total surgery time for the ventral midline approach (group A) and minilaparotomy/grid approach (group B) were 22±4 minutes and 17±3 minutes, respectively.
The duration of gastropexy did not differ significantly between treatment groups A and B. The mean and SD gastropexy times for the cadavers in groups A and B were 7±3 minutes and 5±1 minute, respectively.
Maximal tensile load to failure was not significantly different between treatment groups A and B. The mean and SD for the gastropexy sites in cadavers from groups A and B were 83±24 Newtons (N) and 88±25 N, respectively.
Overall, gastropexy failure was attributed to stomach wall tears in 66.67% (16/24) of the cases. Within group A, the stomach tore in 50% of the cases, the body wall and stomach failed in 41.6% of the cases, and tearing of the body wall caused failure in only one case. Within group B, failure was from the stomach tearing in 83.3% of the cases, and from both the body wall and stomach in 16.7% of the cases. In all cases, the tension on the suture material caused tearing of the tissue (the stomach, body wall, or both) and caused the suture material to pull through the tissue(s).
Clinical Case Study
The right-sided grid approach was performed in six clinical patients. The total surgery time varied from 32 minutes to 58 minutes, with a mean total surgery time of 46 minutes. The gastropexy times ranged from 6 to 9 minutes, with a mean of 7 minutes. All patients recovered uneventfully from surgery.
Postoperative complications of increased heart rate and restlessness occurred during the first 12 hours (in six dogs), and seroma formation occurred in the Louisiana Catahoula leopard dog. All animals were discharged on the day of surgery. Postoperative discomfort was controlled with oral, nonsteroidal, anti-inflammatory medication.g Two weeks postoperatively, a large seroma formed over the incision site of one dog. Results of an ultrasonographic evaluation and aspirate of the fluid were consistent with a seroma. The seroma resolved spontaneously.
Survey radiographs were within normal limits. Contrast gastrograms showed a flat region of the gastric antrum parallel to the right body wall, consistent with a gastropexy in five of six dogs. In the Louisiana Catahoula leopard dog that developed a large incisional seroma 2 weeks postoperatively, the gastric antrum was not visualized at the body wall but was in an anatomically normal position. A duodenopexy was suspected based on the contrast gastrogram, because the duodenum was consistently positioned against the body wall. Total gastropexy failure was not ruled out. No abnormalities in gastric motility were detected in any of the six dogs.
Discussion
A 92% reduction in risk of recurrence of GDV occurs in dogs that receive gastropexies versus those that do not.4 Research has historically focused on gastropexy techniques performed at the time of surgical treatment of GDV. A ventral midline celiotomy is needed for GDV treatment; thus, gastropexy techniques have been performed through this approach. With increased knowledge of the epidemiology of GDV,5 it is becoming possible to determine breeds and even individual dogs at risk. Dogs at risk for GDV would benefit from a prophylactic surgical procedure that is simple for the veterinary practitioner to perform. A gastropexy performed for prophylaxis does not require a midline approach. The minilaparotomy right-sided grid approach used in this study allows the practitioner to perform a standard incisional gastropexy through a limited skin incision using standard surgical equipment without assistance. With a mortality rate of 10% to 60% with GDV, performing a right-sided prophylactic gastropexy should be considered in all at-risk dogs.
In the pilot cadaver study, the right-sided grid approach resulted in a faster, less invasive technique than the ventral midline approach for performing a strong, right-sided incisional gastropexy. This much smaller skin incision (6 cm versus 20 cm) should minimize morbidity and is located in an area not stressed by body weight. The right-sided grid approach did not require special instrumentation or special training. A similar grid approach has been used for gastric decompression via gastrostomy,6 for a left-sided prophylactic gastropexy,7 in combination with a laparoscopic-assisted gastropexy,3 and for placement of a duodenostomy tube.2 The right-sided grid approach was not difficult to perform and gave access to the gastric antrum. The muscle layers are readily defined in this approach. Once in the abdomen, either the stomach was easily identified or required palpation to locate it. Palpation was either of the stomach or duodenum. In two cases (i.e., the Labrador and golden retrievers), the gastric antrum was immediately visualized upon entering the abdomen. These two dogs had the least abdominal fat of the six dogs. In cases where the stomach antrum was not immediately visualized or palpated, following the descending duodenum in an oral direction allowed the surgeon to identify the gastric antrum. The descending duodenum lies ventral to the epaxial musculature and is identified by the proximity of the right pancreatic limb. Large amounts of abdominal fat in the Belgian Malinois and Louisiana Catahoula leopard dog (with suspected duodenopexy) increased the difficulty of locating the gastric antrum. Adhesive peritonitis, gastric foreign bodies, and stomachs heavy with food would all increase the difficulty of the surgical technique. The authors recommend that this technique be practiced before attempting it in clinical cases. Due to their body conformation and personality, the greyhounds selected for participation in this study were considered at risk for GDV. One paper8 featured a clinical evaluation of a gastropexy technique in five greyhounds, because two previous greyhounds had suffered from GDV.
A right-sided grid approach leads to a smaller surgical field with each layer penetrated.7 A 6-cm skin incision was made for a 3-cm incision in the gastric antrum. Each muscle layer has a different orientation, and that makes the surgical field successively smaller. Using retractors on the incision edges helped retract each muscle layer of the surgical approach and assisted with visualization in the abdomen. A 6-cm long incision is a guideline and should be modified for the size of the dog. Some consideration should also be given for the size of the surgeon’s hand. The incision length used in this study allowed abdominal palpation by two fingers in size 7 gloves; surgeons with larger hands may need a larger skin incision for the right-sided grid approach or may need to use a standard ventral midline approach.
In the pilot cadaver study, the total surgical time was significantly less in group B (i.e., the right-sided grid approach). This shorter surgical time for the right-sided grid approach was attributed to a shorter incision. In the clinical cases, the total surgery time ranged from 32 to 58 minutes, which was much longer than the pilot cadaver study total surgical time. This variation in surgical time was due to differences between dogs in bleeding tendencies, amount of time to locate the gastric antrum, and anesthetic depth. Several animals required more time dedicated to hemostasis. Time devoted to hemostasis was not recorded, but the authors felt retrospectively that there was different skin and subcutaneous vessel damage between dogs. Abdominal fat hindered locating and positioning the gastric antrum as previously mentioned. The youngest animal (golden retriever) and most lean animal (Labrador retriever) had the fastest surgical procedures (33 and 32 minutes, respectively). In four of six clinical cases, palpation of the duodenum and gastric antrum resulted in increased heart and respiratory rates. When this occurred, tissue manipulation was delayed until a deeper plane of anesthesia was achieved, which led to longer total surgery times.
In the pilot cadaver study, the actual gastropexy times were not statistically different between groups A and B. Once the stomach and body wall were positioned, the suturing was similar. The gastropexy times in the pilot cadaver study and clinical cases were similar.
Maximal tensile strength (N) to failure has been used to test and compare gastropexy techniques.39–13 In the pilot cadaver study, the mean maximal tensile strength to failure of the right-sided grid-approach gastropexy was not statistically different from the ventral midline-approach gastropexy. The right-sided grid-approach gastropexy values found in the current pilot cadaver study (88±25 N) were higher than other incisional gastropexies10–12 reported in a range of 0 to 100 days postoperatively. Rawlings, et al. showed an ultimate load of 106.5±45.6 (mean±SD) N at 30 days postoperatively. Unfortunately, the maximal tensile force needed to prevent GDV is not known and may differ between individual dogs. Additionally, the maximal tensile strength has been tested at many different postoperative times. If tested immediately postoperatively or in cadavers (as in this pilot study), the strength is from holding layers and suture material. If tested later, the strength should be from the combination of suture material, holding layers, and the healing between the two structures. There are no indications from this study, however, that a right-sided incisional gastropexy performed through a right-sided grid approach differs substantially from a right-sided incisional gastropexy performed through the traditional ventral mid-line approach;311 however, in this study, clinical cases were only followed for four weeks postoperatively, preventing direct evaluation of long-term gastropexy outcome.
In the clinical cases of this study where a right-sided grid approach was used for a prophylactic gastropexy, a barium gastrogram was performed 4 weeks postoperatively. Gastrogram findings were similar to those previously reported for prophylactic gastropexies,814 with the exception of the Louisiana Catahoula leopard dog that developed a large incisional seroma. The gastrogram in this case was not consistent with a persistent gastropexy but suggested that a duodenopexy was actually performed. However, in this case, visualization of the gastric antrum during surgery makes it unlikely that the duodenum was sutured to the body wall. It is, therefore, possible that the seroma formation was associated with the tearing of the stomach from the body wall and possible adhesion of the duodenum to the surgical site. Breakdown of the gastropexy site could occur from improper suturing technique (e.g., not including the transversus abdominus fascia), from suture breaking, or from suture tearing through the tissue. To ensure that the incisional gastropexy is in the correct location in the gastric antrum, the authors recommend visualization of the omental attachments, right gastric vessels, and right gastroepiploic vessels as well as palpation of the pylorus. These anatomical landmarks confirm placement of a proper gastropexy.
Conclusion
The use of a right-sided, minilaparotomy grid incision, performed with the dog in left-lateral recumbency, allowed access to the antrum of the stomach for performing a prophylactic incisional gastropexy. This technique has an advantage over recently described laparoscopic techniques31012 in that no specialized equipment is needed to perform the procedure. The right-sided grid approach in cadavers resulted in a gastropexy with a maximal tensile strength comparable to one performed via a ventral midline approach. This procedure should be reserved for patients that are at an increased risk for GDV and are not obese. Future clinical trials are indicated to confirm that a prophylactic gastropexy does, in fact, decrease the risk of GDV in susceptible dogs.
Balfour retractors; Aesculap Inc., South San Francisco, CA
Babcock intestinal forceps; Aesculap Inc., South San Francisco, CA
Nylon; Sherwood Davis & Geck, Gossport, United Kingdom
Maxon; Sherwood Davis & Geck, Gossport, United Kingdom
Model 1122; Instron Corporation, Canton, MA
Analyse-it, version 1.61; Leeds, England, United Kingdom
Rimadyl; Pfizer Animal Health, New York, NY
Acknowledgments
The authors thank Tim Seaboch for designing the testing apparatus and Bonnie DeYoung and Fonda Martin for their technical assistance.
Citation: Journal of the American Animal Hospital Association 39, 4; 10.5326/0390397
Citation: Journal of the American Animal Hospital Association 39, 4; 10.5326/0390397
Citation: Journal of the American Animal Hospital Association 39, 4; 10.5326/0390397
Citation: Journal of the American Animal Hospital Association 39, 4; 10.5326/0390397
With the dog in left recumbency, the right 13th (A) and 12th (B) ribs were palpated to determine the location of the 6-cm skin incision (C) for the grid approach.
Blunt dissection in the direction of the fibers of the external abdominal oblique (A) and internal abdominal oblique (B) muscles exposes the transversus abdominus muscle (C).
Stay sutures held the stomach in the surgical field for the gastric incision and suturing.
The serosa and muscularis layers of the stomach have been sutured to the cut edges of the transversus abdominus muscle.
