Surgical Treatment of Gastroparesis

Abstract

Gastroparesis and intestinal dysmotility are life-altering diagnoses with no cure. Lifestyle changes, pharmacological, and surgical interventions are combined in a multidisciplinary fashion to improve the quality of life in this patient population. Starting with lifestyle changes, adjustments are made to the types and amounts of food consumed, medical conditions are optimized, and the use of narcotic pain medications as well as smoking is discontinued. For many, these changes are not enough, and antiemetics and promotility agents are used to control symptoms. Finally, when these measures fail, patients turn to surgery, which can include surgical alterations to the stomach, implantation of a gastric stimulator, placement of drainage tubes, and possibly even the complete removal of different organs, including the stomach or gallbladder. In our clinic, patients not only see a surgeon but also a gastroenterologist, dietitian, and psychologist. We strongly believe in a multidisciplinary approach to this condition. The goal is to provide patients with hope and help them live fuller and happier lives.

The study primarily addresses technical considerations and the surgical approach for patients diagnosed with gastroparesis. It outlines the entire process, starting from preparations before the surgery, encompassing the preoperative work-up, and detailing the steps involved in the surgical procedure. One of the key diagnostic challenges faced in treating gastroparesis patients is determining the underlying cause of the condition, as this information is critical for selecting the appropriate surgical intervention. Once the patient's condition has been categorized based on the cause, the medical team engages in a discussion with the patient regarding potential treatment options, which may include endoscopic procedures, minimally invasive techniques, or open surgery.

Introduction

Normally, food moves through the stomach into the intestines via coordinated contractions of the stomach, which are controlled by interstitial cells of Cajal (ICC) located throughout the gastrointestinal tract. Gastroparesis is a syndrome characterized by delayed gastric emptying in the absence of mechanical obstruction and is associated with multiple symptoms, including nausea, vomiting, early satiety, abdominal bloating, and abdominal pain¹.

The most common causes of gastroparesis include diabetes, idiopathic factors, autoimmune conditions, and post-surgical situations where an injury to the vagus nerves results in pylorospasm, inhibiting the stomach's ability to empty normally. This diagnosis is significant because it profoundly impacts patients' lives, limiting their activities by 67.5%, increasing unemployment rates, and significantly reducing their quality of life^2,3,4. Healthcare systems are also affected, with gastroparetic patients experiencing a 158% increase in hospitalization and an average cost of $32,563 for inpatient stays^4,5. Therefore, it is crucial to identify and support these patients in the outpatient setting before they require hospitalization. Most importantly, it's essential to provide these patients with hope, as gastroparesis, like many other chronic diseases, cannot be cured. The best we can offer at this time is the management of patient symptoms. This article aims to summarize the approach and technical considerations for the surgical treatment of gastroparesis patients, enabling them to lead more fulfilling lives.

Symptoms
In half of gastroparesis patients, the cause of symptoms is idiopathic or unknown, while in the remaining cases, their symptoms are categorized as diabetic, post-surgical, autoimmune, or neurologic⁶. Common symptoms include nausea, vomiting, early satiety, abdominal bloating, and abdominal pain. Less common symptoms encompass changes in blood sugar levels, loss of appetite, fluctuations in weight (either loss or gain), and gastroesophageal reflux disease⁷. Older patients may exhibit differences from younger patients, experiencing more early satiety and bloating instead of nausea and vomiting⁸. It's worth noting that female patients are four times more likely to develop gastroparesis⁹.

Diagnosis, assessment, and plan
There are no physical exam findings for the diagnosis of gastroparesis. Multiple tests should be performed to confirm the diagnosis of gastroparesis. The first step is an upper gastrointestinal endoscopy for those with suspected delayed gastric emptying. In cases where the endoscopy results are negative, the next step is to establish gastric dysmotility. The gold standard for diagnosing gastroparesis is a 4 h gastric emptying study. (Previously, 2 h gastric emptying studies were recommended.) To be diagnostic for gastroparesis, 4 h gastric emptying studies should show >10% retention of a food bolus at 4 h¹⁰. These studies are exclusively used to diagnose gastroparesis, and no additional diagnoses are considered based on the results of this test. An alternative to the gastric emptying study is ¹³C breath testing using octanoate or spirulina incorporated into a solid meal, with measurement of the expiratory 13-CO₂ concentration (by mass spectrometry or infrared spectroscopy)¹¹.

An upper gastrointestinal series (UGI) with small bowel follow-through (SBFT) can also be essential when evaluating patients for a diagnosis of gastroparesis, as can CT or MR enterography when the need to limit radiation exposure arises. These are used to rule out distal obstruction, which could present as pseudo-gastroparesis, and to rule out other pathologies, including small bowel masses and strictures. Other studies of bowel function may be considered in patients with gastroparesis, such as wireless motility capsule or a SITZ marker study. These are useful to rule out other motility issues in the bowel, such as global or distal intestinal dysmotility¹².

After reviewing the patient's workup, it is important to determine which prior treatments patients have already undergone. Previous interventions, such as dietary modifications, medical optimization, and lifestyle changes, should be carefully reviewed. This includes cessation of smoking, discontinuing narcotic pain medications, and trials of anti-emetic and prokinetic agents. If patients are refractory or only partially improved with dietary modifications, medical optimization, and lifestyle changes, then surgical intervention should be considered. Surgical treatment options depend on the type of gastroparesis a patient has. For example, if a patient has post-surgical gastroparesis, they are not offered a gastric stimulator, as prior damage to the vagus nerve renders this modality futile. Otherwise, patients may be offered a gastric stimulator, pyloroplasty (either operative or endoscopic), feeding tubes, or even a subtotal or total gastrectomy.

Other previous surgical interventions also need to be considered. Patients may have had feeding tubes or other devices placed for nutrition and resuscitation, which can impact future surgical operative decisions. Additional considerations include prior endoscopies with dilation or botulinum toxin injection into the pyloric muscle. While botulinum injection is controversial, it is still widely practiced, raising concerns about scarring. This extrapolation comes from achalasia studies showing submucosal fibrosis, which could make myotomies more difficult¹³. In our practice, we tend to perform an endoscopy with dilation of the patient's pylorus using a 20 mm balloon at full volume for 1 min. This is performed to test the outcomes of stretching the pylorus before offering permanent transection.

In summary, surgical decision-making is based on a combination of patient preference, the severity of the patient's condition, and the aforementioned factors. Each of these procedures comes with unique risks and benefits associated with their approach.

Protocol

This protocol has received approval and adheres to the guidelines of the Institutional Review Board of the University of South Florida. These guidelines affirm that respect for all forms of life is an inherent characteristic of biological and medical scientists conducting research. Written informed consent was obtained from all patients prior to the procedures. The study included patients aged over 18 years with chronic, intractable (drug-refractory) nausea and vomiting resulting from gastroparesis of diabetic or idiopathic origin. Patients requiring routine MRI imaging were excluded from the study.

1. Gastric per oral endoscopic myotomy (G-POEM)

1. Prior to the procedure, instruct the patients to consume liquids exclusively for 3 days.
2. Place patients under general anesthesia (following institutionally approved protocols) and perform intubation.
   NOTE: The method of induction is typically determined by the anesthesia team, but rapid sequence intubation to minimize the risk of aspiration is preferred.
3. In either the supine or left lateral position, insert a bite block (see Table of Materials) into the patient's mouth.
4. Advance the endoscope into the patient's esophagus and stomach to assess the pylorus. If there is concern about the presence of large amounts of retained food in the stomach (which could hinder case completion) or if any other abnormalities are observed, consider aborting the procedure.
5. Once the decision is made to proceed with the operation, withdraw the scope and secure a cap to the end of the scope.
6. Advance the scope into the pre-pyloric region. Utilize an endoscopic needle (either proprietary elevating fluid or saline mixed with epinephrine, see Table of Materials) to inject fluid and create a submucosal wheal. This can be done either in the lesser or greater curve at the patient's pylorus.
   NOTE: The lesser curve approach, as detailed by Brown et al.¹⁴, is preferred in this case.
7. Use the endoscopic knife to create a transverse mucostomy, entering the submucosal plane.
8. Elevate and divide the submucosal plane until the pylorus is clearly visible. Endoscopically cut the pylorus.
9. Control any bleeding using electrocautery through the endoscopic knife or coagulation graspers.
10. Close the mucostomy with endoscopic clips or other closure devices, such as an endoscopic suturing device (see Table of Materials).
11. Keep patients overnight for observation and initiate them on a PPI (Proton Pump Inhibitor) and carafate. Start a liquid diet immediately. Perform an upper gastrointestinal series at the surgeon's discretion.
12. On postoperative day 1, discharge the patient home. Schedule a follow-up appointment two weeks postoperatively.
13. Instruct the patient to follow a liquid diet for two days, followed by a soft food diet. At the follow-up visit, liberalize their diet and discontinue acid suppression medications.

2. Gastric neurostimulator placement

NOTE: This procedure can be performed either simultaneously or separately from a pyloric intervention. On the day of the procedure, the patient is placed under general anesthesia (following institutionally approved protocols) and intubated.

1. Access the patient's abdomen in the supine position, either through a laparotomy or minimally invasive port sites (for either robotic or laparoscopic cases).
   NOTE: Port placement is described in Figure 1; if a stimulator is not being placed, then the 12 mm port can remain 8 mm.
2. Upon entry into the abdomen, identify the pylorus and count 10 cm proximally along the greater curve of the stomach. Create marks at 1 cm intervals in the previously identified site.
3. Obtain the leads for the stimulator and use the attached needle (see Table of Materials) to place them in the wall of the stomach. Both needles should be placed in parallel, and the tissue taken with the needle should be through the muscularis layer of the stomach, not into the lumen.
4. Utilize endoscopy after lead placement to confirm that no violation of the lumen of the stomach has occurred.
5. Secure the leads at two positions: at the entry point of the lead with 2-0 silk (see Table of Materials) through the pledget and at the distal end where the needle exited the tissue with the circle bumper and clips. Attach the stimulator to the leads.
6. Use the clinical programmer, enclosed in a sterile pouch (such as an ultrasound probe cover, see Table of Materials), to check the impedance of the device. This impedance should fall between 200 and 800 ohms.
7. Secure the stimulator in the pocket under the skin.
   NOTE: This can be accomplished using permanent suture through the apex of the battery and the underlying fascia, or by closing the overlying fat with absorbable suture.
8. Before concluding the case, check the impedance once more to confirm that the device is functioning normally.
9. If only a stimulator procedure is performed, discharge the patient home on postoperative day 1 and schedule a follow-up appointment in 2 weeks at the clinic for evaluation of their stimulator. They may resume a regular diet.

3. Combined pyloroplasty and gastric neurostimulator

NOTE: In cases where patients have such severe symptoms that a combination of pyloroplasty and gastric neurostimulator placement is warranted, the pyloroplasty procedure is performed first. This can be done through a laparotomy incision or minimally invasively (robotic or laparoscopic).

1. After placing the necessary ports, grasp the falciform ligament and elevate it to expose the pylorus. The pylorus can be identified either visually using the vein of Mayo or endoscopically.
2. Mark the proximal and distal portions of the pylorus with electrocautery. Use 2-0 absorbable suture to create stay sutures at 12 and 6 o'clock positions above the pylorus.
3. Elevate the stay sutures and longitudinally transect the pylorus. After completely dividing the pylorus, close it transversely either in two layers or one layer using appropriate barbed sutures (see Table of Materials).
4. Perform a leak test and evaluate patency with the endoscope in place. Following the completion of the pyloroplasty, proceed with the placement of the gastric neurostimulator as previously described (step 2).
   NOTE: Please note that this combined procedure should not be offered to post-surgical patients, as outcomes with the gastric neurostimulator suggest it is less effective in this population.

Representative Results

After completing these surgical procedures, patients should anticipate a decrease in their overall nausea and vomiting symptoms. The progress of their symptoms is tracked using the Gastroparesis Cardinal Index Scale (GCSI)¹¹. The technical success rate of the G-POEM procedure is 100%, with a yearly recurrence rate of symptoms at 13% or higher¹¹. Gastric electrical stimulation is also effective in controlling gastroparesis, with improvements in GCSI nausea and vomiting. In patients who undergo both pyloroplasty and gastric neurostimulator placement, the results are expected to be even more significant. In fact, a greater than 50% decrease in symptoms should be observed^11,12,13.

For patients with a gastric neurostimulator, device adjustments are typically not made until one month after their operation. This waiting period allows for the resolution of anesthesia effects, postoperative healing, and other factors that may affect the device's efficacy. Long-term management of patients after surgery includes ongoing monitoring for postoperative complications. Pyloric interventions can lead to long-term complications such as bile acid reflux or dumping syndrome, in addition to short-term complications such as bleeding, infection, or leaks. Stimulator placement may result in lead perforation (typically seen with impedance levels exceeding 800), device infection, and, over time, the stimulator will likely need replacement based on the patient's settings. Due to the chronic nature of gastroparesis, symptoms may fluctuate over time. Therefore, it is important to continue monitoring patients longitudinally.

A prospective study was conducted at a single center, involving 120 patients (Figure 2). Among them, 25 patients underwent pyloric surgery alone, 74 received Enterra therapy alone, and 21 underwent combination therapy. The GCSI nausea and vomiting subscale score showed significant improvement from baseline to post-intervention in patients who received Enterra therapy alone or a combination of Enterra and pyloric surgery (PS)¹⁵. However, patients who underwent pyloric surgery alone did not exhibit a significant improvement in their GCSI nausea and vomiting subscale score.

Figure 1: Port placement for gastric stimulator placement and surgical pyloroplasty. This image provides a general guide for port placement when performing either minimally invasive gastric stimulator placement or pyloroplasty. Please click here to view a larger version of this figure.

Figure 2: Efficacy of gastric stimulation in isolation or in combination with pyloroplasty. A prospective study conducted at a single center with 120 patients. 25 patients underwent pyloric surgery alone, 74 received Enterra alone, and 21 received combination therapy. The GCSI nausea and vomiting subscale score from baseline to post-intervention significantly improved in patients undergoing Enterra alone or Enterra + PS; PS alone showed no significant improvement. Please click here to view a larger version of this figure.

Discussion

Gastroparesis is a chronic disease for which there is currently no cure. Therefore, the primary focus of treatment is the management of symptoms. In cases where lifestyle changes, dietary adjustments, and medications do not effectively control symptoms, surgical intervention should be considered. Surgical treatment, such as pyloric surgery and/or the placement of a gastric stimulator, can significantly improve nausea and vomiting symptoms. In fact, when these two interventions are combined, they often lead to a more substantial improvement in the GCSI nausea/vomiting score¹⁵.

The G-POEM procedure has been performed since 2013, with nearly 200 papers published on the topic since then. A recent narrative review, summarizing the current data, supports the use of G-POEM in cases of refractory or primary gastroparesis¹⁶. The procedure is considered safe and effective, with the possibility of repeat procedures if necessary. For patients with idiopathic or diabetic gastroparesis, combination therapy with gastric electrical stimulation may offer the most significant benefit, as these two procedures have an additive effect on controlling nausea and vomiting¹⁵. One remaining question is the difference in benefits between G-POEM and surgical pyloroplasty. Some experts advocate for using G-POEM as the first-line therapy, with the option for repeat interventions. Others are concerned about the possibility of incomplete division of the retained pyloric muscle and the potential for recurrent symptoms^11,17. The answer to this question is currently uncertain.

After the surgical intervention for gastroparesis, it is essential to monitor the patient for improvements in symptoms. This includes adjusting the patient's prokinetic and antiemetic medications, as well as fine-tuning the stimulator settings. While there is no standardized pathway for stimulator adjustment, it is the clinician's responsibility to decide on the best approach. It is crucial to inform the patient that increasing the settings will result in a shorter battery life and more frequent battery exchanges for the device.

If patients do not achieve improvement with the above interventions, other procedures can be considered. For example, if a patient has undergone pyloric intervention without a stimulator, a stimulator can be placed, and vice versa. However, if a patient remains unresponsive to all interventions, including dietary changes, medications, lifestyle modifications, and limited surgical procedures, a subtotal gastrectomy with removal of the remnant stomach and Roux-en-Y reconstruction is the final option in the surgical armamentarium^18,19. While other procedures like sleeve gastrectomy are being investigated, the most tested procedure remains the subtotal gastrectomy^18,19. In patients undergoing subtotal gastrectomy, a 50% improvement in symptoms is expected, but in salvage gastrectomy, only a 42% improvement is seen, highlighting the complex neurological and motility challenges of this syndrome²⁰. When presenting this option to the patient, it is crucial to emphasize that it represents the final treatment choice for this disease process and is not a cure. Patients should also be informed about the immediate postoperative and long-term potential complications of a subtotal gastrectomy, such as the need for a post-gastrectomy diet, the risk of marginal ulcers, duodenal stump leaks, and more.

In conclusion, given that approximately 30% of patients do not experience relief with conservative methods, alternative surgical approaches are becoming increasingly necessary, as we have described. Predictors for their clinical success will need to be monitored over time, but these surgical interventions hold promise for the management of these patients²¹.

Materials

Name	Company	Catalog Number	Comments
2-0 Sutures (absorbable)
3-0 V-loc	Medtronic		For closure of pyloroplasty
Bite Block	Endure	NBBW1-10	Mouth piece for use in endoscopy
Carr-Locke Injection Needle	Steris		Injection needle for creation of wheal
Clinical programmer	N’Vision
Coagrasper Hemostatic Forceps	Olympus	FD-411UR	For control of bleeding
Endoscopic Knife	Olympus	KD-640L	Through the scope knife used for mucostomy
Enterra Gastric leads	Enterra	4351	Leads for device
Enterra Gastric stimulator	Enterra	37800	Implantable device
HybridKnife	Erbe	20150-260 and -261	Alternative endoscopic knife