Pectoralis Minor

If you have permanent paralysis of the muscles that allow you to smile, you may be offered a procedure to recreate the smile. The pectoralis minor muscle is one of the muscles that can be used to do this.

This webpage explains more about the procedure and what to expect, including the benefits, risks, any alternatives and what you can expect when you come to hospital.

If you have any further questions, please speak to the doctor or nurse looking after you.

What is a pectoralis minor re-animation?

In patients who have permanent facial palsy with no ability to create a smile on the paralysed side of the face, surgeons can bring in a muscle from elsewhere in the body to replicate a smile. This is often referred to as a facial reanimation procedure. There are many different muscles that can be used. The pectoralis minor muscle is found on the front of the chest and, when removed, does not result in any weakness in the chest or the arm. As a result surgeons can remove the muscle and transfer it to the face to help patients with facial palsy regain a smile.

For this muscle to work, it must be connected to a nerve that will transmit electrical signals to the muscle and stimulate it to contract. In the case of a pectoralis minor muscle being used to generate a smile, the nerve used is a cross facial nerve graft connected to the facial nerve on the healthy side of the face. The cross facial nerve graft acts as an extension cable from the healthy facial nerve and means that the new muscle will contract in synchrony with the healthy facial muscles on the other side of the face.

To ensure that the pectoralis minor muscle gets a new nerve supply, the surgeon will usually allow at least six months for the nerve fibres to grow within the cross facial nerve graft from the healthy side to the paralysed side of the face. This means that two separate operations will be required for a pectoralis minor muscle procedure.

Once the muscle has been placed into the paralysed side of the face, it will take at least three months for the nerve fibres to grow into the muscle and start making it contract. As a result, you should not expect to see any smile forming on that side of the face during this time. It can take around two years to see the final result.

Who is a suitable candidate?

This procedure is suitable for those who have a facial palsy that will not recover. Typically, surgeons will wait around two years to be sure that there are no signs of recovery before offering this procedure.

Another factor to consider is that this procedure requires two operations, one of which is around 8 hours long. As a result, surgeons will only offer this procedure if they feel that you do not have any other medical problems that may make an operation of this length unsafe for you.

A final consideration is that this operation requires new nerve fibres to develop. It has been shown that a number of things can affect the ability of nerves to regrow and the surgeon may advise against this procedure if they feel your body may not be able to regrow nerves sufficiently.

What are the risks?

In general the risks of any operation relate both to the anaesthetic and to the operation itself. The operation is performed under general anaesthetic, which means that you are asleep throughout. Your anaesthetist will go through the risks relating to the general anaesthetic with you before the operation.

Before suggesting the operation, your surgeon will have considered that the benefits of the procedure outweigh any disadvantages. However, in order to make an informed decision and give your consent, you need to know and be aware of the possible side effects, risks and complications. These include:

Bleeding and haematoma: If bleeding occurs after the surgery, it creates a collection of blood underneath the skin called a haematoma. This will require a further operation to be performed whilst you are still in hospital to remove the collection of blood.

Infection: All operations are at risk of causing an infection. This can occur in around 2-5% of these operations. You should look out for increasing pain, redness and fluid discharge from the wound and fevers as a sign that you may have a wound infection. This will require antibiotics and possibly re-admission to hospital.

Scars: Wherever a cut is made, a scar will form. To begin with the scar will become red and raised, but over the coming two years it will continue to soften and flatten. On occasions, scars can remain thick and raised and in this situation the surgeon will offer you some treatments to try and reduce this. In all cases, it is important that you massage the scar a couple of times a day once the wound has healed to help soften the scar. This should be continued for two years.

Asymmetry: The side of the face that has been operated upon will never move in exactly the same way as the normal side. This is because one muscle is being used to recreate the function that was previously performed by many small muscles. Despite this, excellent results can be achieved.

Bulkiness: Because an extra muscle has been moved into the face, it will give the appearance that that side of the face is bulkier than the other side. This improves with time as the muscle shrinks down slightly and every effort is made to try and match the volume between the two sides of the face. If bulkiness remains a problem, then a further operation is an option to try and correct this.

Muscle transfer failure: This can occur for a number of reasons. Firstly, the blood vessels that were connected together to deliver oxygen and nutrients to the muscle may get blocked. It is for this reason that you are closely observed whilst in hospital to identify this problem. If the blood vessels do get blocked, then you will be taken back to the operating theatre quickly to try to correct this. This problem can occur in around 2-5% of cases.

Secondly, the nerve fibres may not successfully grow into the muscle and it will, therefore, have no nerve supply to make it contract.

Unfortunately, this problem only becomes evident after many months when it becomes clear that the muscle is not going to start working. This is why the surgeon will be sure that you a good candidate for making nerves regrow before offering you this operation.

Finally, it is possible for some of the sutures holding the muscles in place in the face to come loose. This will affect the way the muscle pulls on the corner of the mouth when it contracts. If this were to occur, the surgeon is likely to offer you another operation to correct the position of the muscle.

Are there any alternatives?

This is not a life-saving procedure and, therefore, the main alternative is to have no surgery at all. If you have decided that you would like surgery to improve your appearance and the function of your face, other alternatives do exist. Broadly speaking these can split into those that improve the symmetry of your face at rest but do not produce any movement (static procedures) and those that improve the position at rest and can produce movement of the face to express emotions (dynamic procedures). The pectoralis minor muscle transfer is a dynamic procedure. The main advantages of static procedures are the shorter length of surgery and hospital stay, the ability to perform the surgery in one operation and the reduced risk of failure. Many options exist in both categories and your surgeon can discuss these with you.

How can I prepare for a pectoralis minor operation?

You will need to take time off work for the surgery. To begin with, you will be in hospital for around five days. After this, we would recommend that you take a further two weeks off work to recover. If your job involves heavy exertion, you should take a total of one month off work.

Any sports should be avoided for 4-6 weeks and you should try to stop or cut down any smoking in the lead up to the operation and for the six weeks following surgery. Smoking will increase the risk of the muscle not working and the wound not healing.

With this being an operation performed under general anaesthetic, you will need to avoid any food in the six hours before surgery. You may drink water up until two hours before surgery.

Prior to coming in for surgery you will most likely be seen in a pre-assessment clinic. In this clinic they will go through any other medical problems that you have and list any medications that you take. Advice will be given on which medications to stop before surgery.

What does the surgery involve?

This operation is done in two steps. The first operation involves performing a cross facial nerve graft (please see link for details).

The second operation involves transferring the pectoralis minor muscle to the paralysed side of the face. This is the longer of the two operations and takes around 6-8 hours to perform. A cut is made on the paralysed side of the face just in front of the ear and along the jaw line. This allows the surgeon to make a pocket in which they can place the muscle and also allows them to find the end of the cross facial nerve graft and the blood vessels that will be connected to the muscle.

A separate cut, around 10cm long, is then made in one of the armpits to find the pectoralis minor muscle. The muscle is then removed with its blood vessels and nerve attached.

The muscle is then stitched into the pocket made in the face and attached around the mouth in such a way that when the nerve fibres from the cross facial nerve graft stimulate the muscle to contract it will create a smile. Finally, the blood vessels in the face are connected to the blood vessels on the muscle so that it has oxygen and nutrients being delivered to it. Furthermore, the cross facial nerve graft is stitched to the nerve in the muscle so that nerve fibres can start to grow into the muscle.

The cuts are then stitched back together again and a big head bandage is placed over the head to limit the amount of swelling you will get in the face.

Will I feel any pain or discomfort?

After the surgery it is likely that you will feel some pain, although you will be given a number of different painkillers to reduce and ideally remove this pain. The pain is normally around the wounds themselves and should begin to subside in the first 72 hours after surgery. By the time you go home your pain should be low enough to be controlled by paracetamol alone.

What happens after the surgery?

Whenever surgeons move muscles and have to reconnect the blood vessels in another place, it is important that the patient is closely observed to ensure that the blood continues to flow across the join that has been made. This means that you will be closely monitored in hospital for 3-5 days and will have a number of tubes connected to you including a catheter in the bladder that measures how much urine you make each hour.

You should expect your face to become very swollen after the operation and this will take a couple of weeks to subside. To begin with, you will find it difficult to eat and drink normally similar to how it would feel after a trip to the dentist. Sleeping propped up on a few extra pillows at night will help to reduce this swelling quicker.

Will I have a follow-up appointment?

Your surgeon will make arrangements to see you around one week after leaving hospital to check that all is well with the wounds. They will also arrange an appointment to see you in their outpatient clinic at which point you will be given guidance on the exercises you should begin to practice to help the muscle start to work in the correct way. This will be done with the help of a physiotherapist experienced in managing patients with your condition.

What should I do if I have any concerns?

If, following the surgery, you have any concerns you should contact your surgical team or the ward that you were admitted to during your stay. They will then be able to give you further advice on what to do and whether they need to see you back at the hospital or not.

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Last reviewed: 11-12-2015    ||    Next review due: 11-12-2017