Botulinum Toxin Injection
Introduction
Botulinum toxin injection (Botox Injection) is a non-surgical procedure used to treat achalasia, where the lower oesophageal sphincter fails to relax and oesophageal peristalsis is disrupted. During the procedure, endoscopy is utilised to inject botulinum into the zone surrounding the lower oesophageal sphincter resulting in muscle paralysis. This allows food to be able to pass into the stomach. It is commonly used in patients who are either waiting for, or not fit for a laparoscopic heller myotomy surgical procedure.
The procedure is performed either under sedation, or a local throat anaesthetic spray. Recovery is quick, with the patient being discharged after one hour from the procedure end and post-operative care usually involves restricting any heavy lifting/driving within the first 24 hours after discharge.
Complications of the procedure are rare, with the main complaint being postoperative chest pain and heartburn. This is usually transient in most patients. Botox Injections are useful for short term treatment, as effects may wear off after several months and hence repeat injections may be necessary.
What is it?
Botox Injection is a nonsurgical procedure used in the treatment of achalasia. It involves the injection of Botulinum Neurotoxin Type A, a potent acetylcholine inhibitor, into smooth muscle cells such as is found in the lower oesophageal sphincter. The toxin is a naturally occurring substance produced by the bacterium Clostridium Botulinum. The injection of this substance into smooth muscle results in muscle paralysis, which can last from anywhere between a few months to a year. The injection induced relaxation of muscles allows food to pass from the oesophagus into the stomach and continue digestion as normal (1).
Botox Injections are conducted in conjunction with endoscopy, which allows access and visualisation of the lower portion of the oesophagus for the surgeon.
Why is it done?
A Botox Injection is used in the treatment of achalasia, which is a functional disorder where the lower oesophageal sphincter fails to relax and there is a lack of coordinated peristalsis (contractions) of the oesophagus. This causes food and liquid build up in the oesophagus and prevents food from passing into the stomach for digestion. The cause of achalasia is not fully known but its signs and symptoms are well recognised.
There is no definitive cure for achalasia, and hence treatments are focused on alleviating the symptoms and providing the best possible care. The gold standard treatment for achalasia is a surgical procedure known as a laparoscopic Heller myotomy. This involves the dissection of the longitudinal muscle fibres that form the lower oesophageal sphincter, thus allowing food to pass through into the stomach. It follows that laparoscopic Heller myotomy provides the most long-term solution for achalasia. The other treatments include:
- Pneumatic Balloon Dilatation
- Botox Injection
- Medical Treatments using calcium channel blockers and nitrates
These other treatments and non-surgical procedures do not provide as long a relief from the symptoms of achalasia than a laparoscopic Heller myotomy does, and may require repeat procedures at intervals of between 1 - 5 years as there may be a recurrence of symptoms. However, there may be certain cases where a non-surgical approach such as a Botox Injection is performed instead of the gold standard surgical approach. These include:
- If the patient is scheduled for a laparoscopic Heller myotomy and symptomatic relief is needed in the meantime.
- If the patient is not a candidate for surgical procedures due to the presence of other co-morbidities and diseases.
- If the patient does not want an invasive surgical procedure, and would rather a non-surgical approach (3).
Botox Injections can also be used as the next step in the management of achalasia following unsuccessful treatment with either a pneumatic balloon dilatation or a surgical myotomy. The treatment can also be used in combination with pneumatic balloon dilatations, both of which are non-surgical interventions. This combination therapy has been shown to result in a higher success rate in some studies of around 57% compared with 36% for pneumatic balloon dilatation alone (4).
Will I need any preparation?
You will be required to fast for at least 12 hours before the procedure is scheduled to take place. If the achalasia is severe, you may be prescribed a liquid diet for the 24-48 hours preceding the procedure.
Before the procedure, you will have an appointment with the doctor who will go through on the day procedures and talk to you about the different options for treatment, alongside consulting you on whether you would like to be given a sedative during the procedure to make it more comfortable. If you are on any anticoagulation medication such as warfarin or clopidogrel, your doctor will need to know this so they can take appropriate measures and if necessary ask you to stop taking these medications a few days before your procedure. This is to prevent large amounts of bleeding during the procedure.
Technique
Anaesthesia
You will need to be awake during the procedure and hence general anaesthetic is not routinely given. However, many patients may find the procedure uncomfortable, and hence there is the option to be given a sedative. This will not put you to sleep, but will help you relax and make the procedure more tolerable. You may be offered a local throat anaesthetic spray to numb your throat if necessary. The benefit of the anaesthetic throat spray is that you will be able to go home alone after the procedure has finished as you will be fully awake and alert. You can discuss the options with your anaesthetist before the procedure will take place.
What does it involove?
Botox injection is conducted in conjunction with a standard endoscopy. This allows for an initial diagnosis to be made to confirm that no other disease is causing the difficulty swallowing, and the injection can be delivered through this route. Hence the procedure begins by conducting an endoscopy:
1) The first stage of the procedure involves applying either the sedative intravenously, or the local throat anaesthetic.
2) You will be placed on your left side on the bed with your head bent forward, allowing proper orientation and for the endoscope to pass down more easily through the oesophagus.
3) A mouthpiece will be placed between your teeth to prevent damage and to keep your mouth slightly open for the OGD tube to enter. Any excess saliva in the mouth will be removed using a specialised sucking tool.
4) The endoscopist will lubricate the tube to make it easier and more comfortable to slide down your throat. The OGD tube will be inserted through the mouthpiece over your tongue and passed down through the oesophagus. The endoscopist will pay careful attention to the structures in the mouth and may inspect the area for some time before inserting the endoscope. This is often the most uncomfortable stage for the patient.
5) At this stage, the endoscopist will check the lower oesophagus for any other issues or diseases that may explain the difficulty swallowing. The camera on the end of the endoscope allows the surgeon to visualise the gastro-intestinal tract and to check for any malignancy (cancer) which may be present at the cardia of the oesophagus (region that borders the oesophagus entry into the stomach). This malignancy is known as pseudoachalasia and can mimic the signs and symptoms of primary achalasia. This is rare and if the doctors find this, they may take a biopsy for review and stop the procedure at this point.
6) If the endoscopist needs to get a better view, they may pass some air down the OGD tube, which may make you feel slightly bloated. Photographs may be taken using the camera which will be added to your medical record.
7) Once the lower oesophageal sphincter has been visualised, an injection will be made into each of the four quadrants above the Z-line of the oesophagus. This is the region where your oesophagus meets the stomach and the cell type changes. The injections are made through a special needle that is passed down through the accessory channel of the endoscope (6).
How long does it take?
The procedure is performed either under sedation, or a local throat anaesthetic spray. Recovery is quick, with the patient being discharged after one hour from the procedure end.
Post procedure course (follow up)
After the procedure you will be transferred to a recovery ward, allowing you to rest until the major effects of the sedative wear off. Here, you will also have your vital signs checked. If you have been administered sedation, you will have to get someone else to pick you up from the hospital and stay with you for the next 24 hours. If you have only had a botox injection, you will usually be discharged an hour after the procedure has finished, and can expect to feel an improvement in the symptoms after 24 hours.
If you have had a simultaneous pneumatic balloon dilatation, you will be kept in the recovery room and closely monitored for 5-6 hours after the procedure has finished, as it tends to be during this time period that the signs and symptoms of oesophageal perforation manifest themselves, including:
- Chest pain - This is particularly indicative of perforation if the chest pain lasts for more than 4 hours after the procedure has finished (7).
- Tachycardia
- Worsening discomfort
If you do experience any of the above symptoms, the doctors may order an urgent scan using barium swallow (a contrast agent). This will allow them to visualise the area of perforation, which can then be addressed surgically if necessary. In some hospitals, a scan of the oesophagus after a barium swallow is done in all patients who have had a pneumatic balloon dilatation as a precaution (8).
post-operative care usually involves restricting any heavy lifting/driving within the first 24 hours after discharge
How long will I stay in hospital?
Around one hour.
What care will I need at home?
Botox injections typically result in a success rate of between 70% - 90%. While botox injections are much less invasive than the surgical approach, the downside is that for most patients, symptoms return after six months (9, 10). This means that you may need multiple treatment sessions. If you are scheduled for a laparoscopic heller myotomy, then the botox injection will help relieve symptoms until your surgery; otherwise your doctor will talk to you about the need to have multiple treatment sessions. Furthermore, responses to subsequent botox injections have often shown to be lower than initial injections, and hence a different, more long term therapy may need to be considered (11). If you feel your symptoms returning and you are struggling to swallow again, please speak to your doctor who can either arrange another session or explore different treatment options.
Will I need someone to stay with me?
This is not necessary.
Will I need any special equipment when I go home?
No.
What follow up care is needed?
You will be given a follow up appointment where you can discuss progress and potential further treatment options. This is a good opportunity for you to ask any questions you may have or raise any concerns.
When can I start my normal activities again (e.g. driving, sports, or work?)
After sedation you will be asked to restrict any heavy lifting/driving within the first 24 hours after discharge.