Gastrostomy, Enterotomy, and Anastomosis PDF

# Gastrostomy, Enterotomy and Anastomosis ## Surgery - **Gastrostomy:** Incision of the stomach - Indicated in cases of foreign bodies, biopsies, and neoplasms, gastric dilation, torsion, and gastric volvulus - **Anesthesia Protocol:** - **Analgesic:** Meloxicam 0.1 mg/Kg IV...

# Gastrostomy, Enterotomy and Anastomosis ## Surgery - **Gastrostomy:** Incision of the stomach - Indicated in cases of foreign bodies, biopsies, and neoplasms, gastric dilation, torsion, and gastric volvulus - **Anesthesia Protocol:** - **Analgesic:** Meloxicam 0.1 mg/Kg IV - **Tranquilizer:** Acepromazine 0.05 mg/Kg IV - **Inducer:** Propofol 4-6 mg/kg IV - **Maintenance:** Isoflurane ## Anatomy of the Stomach - The stomach is a saccular organ located in the middle and cranial part of the abdomen. - It is protected cranioventrally by the liver and laterally by the costal arch when empty. - It is fixed proximally by the esophageal diaphragm and distally by the pylorus by the hepatogastric ligament. - Mesenteric relationships include the lesser omentum, which extends from the lesser curvature of the stomach to the liver, and the greater omentum or epiploon, mainly originating from the greater curvature, and contains the gastrosplenic ligament attaching the spleen to the greater curvature of the stomach. ## Surgical Technique - Access to the abdominal cavity is achieved via a median ventral incision from the xiphoid process to the umbilical scar and the stomach is exposed. - The stomach is isolated with surgical compresses and two traction sutures are placed 10 cm apart to facilitate manipulation and prevent contamination of the rest of the viscera. - The incision is preferably performed over the least-vascularized area. - The septic phase of surgery begins at this time, and the management of gastric content must be considered. - The layers to be traversed using a puncture incision with a scalpel are the serosa, muscularis, submucosa, and mucosa. The mucosa is loose, and sometimes it is necessary to hold it with forceps for incision. - The interior of the organ is inspected, and foreign bodies are removed or a biopsy is performed. - Closure is performed with a 3/0 absorbable monofilament suture of an invaginating pattern such as Connell. - The septic phase ends with a change of gloves, gauze, compresses, and contaminated instruments. - Closure is also performed with continuous sutures in the mucosa and separate simple sutures involving the other layers. - Finally, the cavity is closed using sterile material. ## Enterotomy - Enterotomy is a surgical technique involving incision of a section of the intestine at the antimesenteric border. - It is performed when there is simple obstruction, to extract foreign bodies, as long as there is no vascular obstruction in the intestinal wall. - Mesenteric circulation is not altered, but the intramural circulation is. - Enterotomy can therefore be used to obtain biopsies throughout the intestine. ## Anatomy of the Intestines - The small intestine is divided into the duodenum, jejunum, and ileum. - It is 1.8-4.8 meters long in dogs. - The duodenum is the most cranial part of the intestine, starting from the pylorus, and running towards the right on a medial plane. - It is located dorsally in the ninth intercostal space. - The duodenum is stabilized by the hepatoduodenal ligament and mesentery that houses the pancreas. - It then runs caudally towards the cranial flexure and begins the descending portion, related to the dorsocaudal aspect of the kidney. - At the level of the fifth and sixth lumbar vertebrae, the duodenum forms an ascending flexure located between the cecum, ascending colon, and the root of the mesentery in the right quadrant, forming the duodenocolic fold. - The transition from the duodenum to the jejunum occurs at the duodenojejunal flexure, located to the left of the root of the mesentery, where the ventrocaudally-directed jejunum passes. - The jejunum has a looser arrangement than other intestinal sections, allowing dorsal and rightward movement when the stomach is full. - The ventrolateral surfaces are covered by the omentum. - The ileum is the most caudal portion of the small intestine and is connected to the cecum by the ileocecal valve. - The ileum is identifiable by an additional peritoneal membrane, the ileocecal fold that joins the antimesenteric border. - It is characterized by the presence of supplemental vessels in this fold and by its thicker wall, containing a more developed circular muscular layer. ## Intestinal Irrigation - The mesenteric artery provides irrigation to the intestine. - It originates at the level of the first lumbar vertebra, below the celiac trunk. - The duodenal portion is supplied by branches of the celiac artery. - The mesenteric vessels of the small intestine form arches that anastomose. - In the case of obstruction of one segment, the rest of the intestine is irrigated by collaterals. - The intestinal vascular bed communicates with the portal system. - The lymphatic drainage courses through the lymph nodes contained in the mesentery, throughout the entire length of the intestine. ## Intestinal Innervation - The parasympathetic nervous system, through the vagus nerve, sends fibers to the small intestine and the first part of the large intestine. - The pelvic nerves also contribute to parasympathetic innervation. - Sympathetic innervation originates from the sympathetic trunk, via the paravertebral sympathetic ganglia located in the abdominal cavity. - Afferent sympathetic and parasympathetic fibers transmit information to trunk nerves and then to the central or peripheral synapse to trigger reflexes. ## Physiopathology - Based on the anatomical location of the obstruction, the patient manifests vomiting or diarrhea, with consequent loss of liquids and electrolytes. - Later, the segment paralyzes, and fluid and gases accumulate, increasing bacterial proliferation, which causes a change in the mucosal permeability and leakage of fluid into the cavity. - The pressure exerted by the foreign body on the walls results in devitalization and perforation. - There are several techniques to assess the intestinal segment involved, such as macroscopic characteristics, such as color, consistency, mesenteric vessel pulsation and peristalsis. - In case of doubt, the tissues are hydrated with isotonic saline solution and reassessed. Alternatively, flourescing dyes can be used, among other methods. ## Diagnosis - **Simple Radiography:** Shows a stepped pattern in the dilated small intestine with air and fluid levels, or evidence of foreign bodies. - **Radiography with barium sulfate:** Confirms the presence and location of the small intestinal obstruction. (Not to be used if perforation is suspected). - **Ultrasonography:** ## Surgical Technique - The patient is placed in dorsal recumbency and a midline ventral celiotomy is performed. - Once the abdominal cavity has been accessed, the affected intestinal portion is exteriorized and isolated with moistened compresses. - It is not recommended to incise the intestine over the foreign body, because the tissue in this area may present physiological changes that delay healing. - However, it is important to determine the extent of any changes in the tissue after incision. - If there is a fistula post-surgery, a resection is recommended. - The intestinal contents are gently moved away from the area to be incised, and intestinal clamps are placed to prevent the leakage of contents through the incision. - Retention sutures are placed, both cranially and distally from the location to be incised. - After the antimesenteric border is incised, the incision is extended to the edge of the intestine, starting the septic stage of surgery. - The size of the incision depends on each case, based on the presence of air and fluid levels, or evidence of a foreign body. - The foreign body is extracted, and an invaginating suture such as Connell is performed, using a 3/0-5/0 absorbable monofilament suture or a simple interrupted suture. - The choice of suture pattern depends on the intestinal diameter. ## Therapeutic Approach - The initial therapeutic approach focus on the restoration of fluids and electrolytes to stabilize the patient. - If intestinal strangulation is suspected, broad-spectrum antibiotics are administered to provide coverage for anaerobic and gram-negative bacteria. - This is a treatment for endotoxic shock due to intestinal obstruction and strangulation. ## Intestinal Anastomosis - An intestinal resection and anastomosis is carried out if there is strangulation of a loop of intestine, which leads to damage from mesenteric vessel compromise, including venous return disruption, sequestration of blood to the intestinal wall, necrosis, alteration of the intestinal permeability. - The patient is placed in dorsal recumbency, and a midline ventral celiotomy is performed to assess the abdomen. - Once the abdominal cavity has been accessed, the affected portion of intestine is exteriorized and isolated with moistened compresses. - It is recommended to hydrate the tissue with a lactated Ringer solution. - The intestinal viability is assessed based on the color, arterial pulse, peristalsis, and serosal luster. - If the viability is compromised, intestinal resection and anastomosis are necessary. - However, the identification of the cardinal signs of intestinal viability is not a guarantee of anastomosis success. - It is generally advisable to resect a larger portion. - The portion to be resected is analyzed and double ligation is placed on the mesenteric vessels, and these vessels are cut between the ligatures. - A ligature is placed on the arcade vessels affecting the serosa and muscularis of the intestine. - The mesentery is then cut. - Four intestinal clamps of Doyen are applied at a 45° angle to occlude the lumen without compromising perfusion. - Two clamps are placed near the affected portion, and two others are placed farther away to prevent leakage of contents. - The affected area is removed using a scalpel incision next to the clamp, while respecting the vessel ligation. - At this point, the septic stage begins. - The mesentery is cut with Metzenbaum scissors, between the double ligatures of the mesenteric vessel. - Bleeding from the intestinal edges is controlled, and the mucosal surface is trimmed if necessary to facilitate union, bringing the two intestinal sections together for suture. - An absorbable monofilament suture is used, with a 3/0 caliber needle with a round tip and a continuous simple suture pattern, maintaining a distance of 2-3 millimeters between each stitch. - Two reference points are placed at the 12 and 6 o'clock positions. - It is recommended to perform the suture at 180°, starting at the 12 o'clock position and ending at the 6 o'clock position, then continuing the stitch from the 6 o'clock position to the 12 o'clock position to create two stitches that provide greater elasticity. - It is recommended to hold the intestinal edges with fine dissection forceps and avoid using fingers, as this can damage the tissue and needle. - This marks the end of the septic surgical stage. - All contaminated materials are discarded, including surgical drapes, compresses, instruments, and gloves used in the presence of intestinal contents. - The mesentery is sutured with a 3/0 absorbable round-tipped needle using an interrupted simple suture pattern. - Doyen clamps are removed, and the closure is inspected to make sure there are no leaks. Physiologic saline solution is injected to check. - Finally, the abdominal cavity is closed conventionally. - Enteral micronutrition is recommended 24 hours after surgery. - If there are no signs of vomiting, soft food is given 48 hours after surgery, every 6 hours, gradually increasing the intake to reach normal levels within 7 days after surgery.