Use of botulinum toxin in the treatment of achalasia

Practical Approaches to the Surgical Management of Achalasia

Achalasia is a primary motor disorder of the esophagus characterized by an abnormal hypertensive, nonrelaxing lower esophageal sphincter (LES) and nonfunctioning, aperistaltic esophageal body resulting in significant regurgitation and dysphagia. The primary goal of treatment is palliation of symptoms. At present, all treatment techniques are directed at relieving the functional obstruction at the level of the LES by disruption or paralysis of the esophageal muscle constituting the LES. Destruction of the LES function also places the patient at risk for pathologic gastroesophageal reflux disease. Therefore, the treatment of patients with achalasia must strike a balance between the relief of dysphagia and potential creation of pathologic gastroesophageal reflux. The advent of laparoscopic esophageal myotomy for the treatment of achalasia over the past decade has resulted in most patients with the disease being referred to surgeons for definitive treatment. At the time of consultation the patient may present with a myriad of symptoms, investigative results, and previous treatments. Based on our experience of over 300 patients treated with surgery at our institution between 1990 and 2007, this review will address the practical problems encountered in the surgical management of achalasia.

Achalasia in a patient with gastroesophageal varices: problematic treatment decisions

The coexistence of achalasia and gastroesophageal varices has been reported sporadically in the English medical literature. We report the case of a 60-year-old Hispanic woman with cryptogenic cirrhosis who was referred for a liver transplant evaluation and subsequently developed progressive dysphagia to both solids and liquids as well as substernal chest pain and weight loss. Endoscopy revealed the presence of grade I esophageal varices and large fundic varices, as well as retained liquid and solid food in the distal esophagus. Radiographic and manometric studies were consistent with achalasia. After botulinum toxin (Botox) injections were no longer effective a transjugular intrahepatic portosystemic shunt was performed for portal decompression before proceeding with pneumatic dilation. Optimal treatment of these 2 conditions, when they occur simultaneously, is problematic. We discuss this patient's management and our approach to this infrequent combination of diseases.

Dysphagia in aging

Dysphagia is a common problem in older patients and is becoming a larger health care problem as the populations of the United States and other developed countries rapidly age. Changes in physiology with aging are seen in the upper esophageal sphincter and pharyngeal region in both symptomatic and asymptomatic older individuals. Age related changes in the esophageal body and lower esophageal sphincter are more difficult to identify, while esophageal sensation certainly is blunted with age. Stroke, Parkinson's disease, amyotrophic lateral sclerosis, Zenker's diverticula, and several other motility and structural disorders may cause oropharyngeal dysphagia in an older patient. Esophageal dysphagia can also be caused by both disorders of motility (achalasia, diffuse esophageal spasm, scleroderma and others) and structure (malignancy, strictures, rings, external compression, and others). Many of these disorders have an increased prevalence in older patients and should be sought with an appropriate diagnostic evaluation in older patients. The treatment of dysphagia in older patients is similar to that in younger patients, but more invasive therapies such as surgery may not be possible in some older patients making less aggressive medical and endoscopic therapy more attractive.

Botulinum toxin in clinical practice

Botulinum toxin, the most potent biological toxin, has become a powerful therapeutic tool for a growing number of clinical applications. This review draws attention to new findings about the mechanism of action of botulinum toxin and briefly reviews some of its most frequent uses, focusing on evidence based data. Double blind, placebo controlled studies, as well as open label clinical trials, provide evidence that, when appropriate targets and doses are selected, botulinum toxin temporarily ameliorates disorders associated with excessive muscle contraction or autonomic dysfunction. When injected not more often than every three months, the risk of blocking antibodies is slight. Long term experience with this agent suggests that it is an effective and safe treatment not only for approved indications but also for an increasing number of off-label indications.

Basic immunological aspects of botulinum toxin therapy

Previous studies in this laboratory had mapped the immune recognition profile of the regions recognized antibodies (Abs) and by T cells on the protective H(C) domain (C-terminal fragment corresponding to residues 855-1296 of the heavy chain) of botulinum neurotoxin serotype A (BoNT/A). The localization of these regions has several potential applications and has provided a basis for the understanding of immunoresistance to treatment. We briefly outline these localized regions and discuss the impact of these findings on the immunotherapeutic applications of BoNT/A. Immunoresistance to toxin therapy can appear in some patients after a few injections with the toxin. Our epitope mapping studies have shown that several factors can influence the immune response to the toxin. These factors include dose, duration of treatment, frequency of immunization, and quality of the toxin. The immune response to the whole toxin is under genetic control, and the response to each epitope is under separate genetic control. Therefore, the appearance of blocking Abs (i.e., immunoresistance) in patients might be controlled by the major histocompatability of the host. Once a patient becomes immunoresistant to one toxin then switching to another toxin will most often be of limited and short-lived benefit, because the patient becomes rapidly immunoresistant to the second toxin. Finally, because of the considerable structural homology between tetanus neurotoxin (TeNT) and BoNTs, it is possible, although not certain, that a prior active immune response to TeNT might play some role in the early appearance on anti-BoNT Abs in some patients.

Internal anal sphincter achalasia in children: clinical characteristics and treatment with Clostridium botulinum toxin

OBJECTIVES

To describe the clinical characteristics of children with internal anal sphincter (IAS) achalasia and to evaluate the benefit of intrasphincteric injection of Clostridium botulinum toxin.

METHODS

Retrospective review of the medical records of 20 patients (8 male, mean 5.8 +/- 4.2 years) with severe chronic constipation and IAS achalasia. Each patient received four-quadrant, intrasphincteric injections of botulinum toxin at a dose of 15-25U per quadrant. Patients were reassessed 4 weeks-18 months after injection. We compared the clinical characteristics of these patients to 20 consecutive children (14 male, mean age 8.1 + 4.6 y) with functional constipation (control group).

RESULTS

The children with IAS achalasia had earlier onset of symptoms, less fecal soiling, and less withholding behavior than the control children. Response to botulinum injection was rated excellent by the parents in 60% and by the physician in 35% of children. There was wide individual variability in the frequency of defecation after therapy. Duration of response ranged from 1 week to 18 months.

CONCLUSIONS

Children with IAS achalasia have clinical characteristics differentiating them from children with functional constipation. Intra-anal injection of botulinum toxin is a safe and effective short-term treatment for these children.

Indications and efficacy of botulinum toxin in disorders of the gastrointestinal tract

In recent years, botulinum toxin type A (BT) has been found to be effective in the treatment of various spastic disorders of smooth muscle in the upper and lower gastrointestinal tract. The short-term efficacy of intrasphincteric injection of BT in achalasia is now well established, however, because of the chronic nature of the disease, patients will require repeated injections at regular intervals. In contrast, after a single injection into the anal sphincter, BT has impressively high healing rate with minimal side effects. BT remains a novel therapeutic approach in a range of other gastrointestinal motility disorders including diffuse oesophageal spasm, sphincter of Oddi dysfunction and anismus, and the list of its indications is increasing. BT seems to be safe but as its long-term effects remain unestablished, it should be used with caution in younger patients. In this review we discuss the mechanism of action, indications, efficacy and side-effects of BT with its use in various areas of gastrointestinal tract.

Thoracoscopic versus laparoscopic modified Heller Myotomy for achalasia: efficacy and safety in 87 patients

BACKGROUND

The ideal treatment for achalasia permanently eliminates the dysfunctional lower esophageal sphincter, relieving dysphagia and regurgitation; prevents gastroesophageal reflux; and has an acceptable morbidity rate. Controversy exists concerning whether the thoracoscopic Heller Myotomy (THM) or laparoscopic Heller myotomy (LHM) technique is the best approach to a modified Heller myotomy for achalasia.

STUDY DESIGN

We performed a retrospective comparison of the patient characteristics, operative results, postoperative symptoms, and the learning curves for the procedures of 24 patients undergoing THM and 63 patients undergoing LHM between 1991 and 1998.

RESULTS

Preoperative patient variables in each group revealed similar distributions for age, gender, and prevalence of previous pneumatic dilation. Mean operating room (OR) times were 4.3 hours (range 2.9 to 5.6 hours) for THM and 3.0 hours (range 1.5 to 6.5 hours) for LHM (p = 0.01). Three esophageal perforations occurred in the THM group and two in the LHM group. Conversion to an open procedure took place in five THM operations (21%) and one LHM operation (2%) (p = 0.005). There were no postoperative esophageal leaks. Mean postoperative length of stay (LOS) for THM was 6.1 days (range 1 to 17 days) and for LHM was 4.0 days (range 1 to 12 days) (p = 0.03). Learning-curve analysis of the first 24 LHM patients compared with the most recent 24 revealed greater OR time in the first 24 mean 3.6 hours, (range 2.0 to 6.5 hours) versus mean 2.3 hours, (range 1.5 to 3.7 hours; p = 0.01), and greater LOS mean 5.5 days, (range 3 to 12 days) versus mean 3.1 days, (range 1 to 8 days; p < 0.01). One esophageal perforation occurred in each subgroup. A similar analysis in the first 12 THM patients compared with the most recent 12 revealed no significant improvement in OR times or LOS. Three esophageal perforations occurred in the latter subgroup only. All patients had preoperative daily dysphagia to solids. Followup data for LHM (n = 49) (median 17 months, range 1 to 39 months) and THM (n = 15) (median 42 months, range 1 to 69 months) revealed no or minimal dysphagia in 90% (44 of 49) after LHM and 31% (4 of 13) after THM (p < 0.01). No or minimal heartburn was present in 89% (41 of 46) after LHM and 67% (8 of 12) after THM (p < 0.05). Regurgitation was absent or minimal in 94% (46 of 49) after LHM and 86% (12 of 14) after THM (p = 0.3).

CONCLUSIONS

LHM was associated with decreased OR time, decreased rate of conversion to an open procedure, and shorter LOS compared with THM. LHM was superior to THM in relieving dysphagia and preventing heartburn. LHM may be the preferred surgical treatment of achalasia in some patients.