Local Steroid Injection for CTS in East Kent

How will arrangements be made for injection and where will it be done?

Injections will be done at a GP surgery or in the neurophysiology department in Canterbury and we will try to arrange it so that it is within easy reach of your home. Not every practice has a doctor who has been trained to carry out this particular steroid injection so it may not be your own practice. To make a booking in primary care we will ask you to telephone the surgery in primary care office who will make the arrangements. It is up to you to telephone them as they will not call you. We generally expect to make appointments for 2-6 weeks after your telephone call.  Injections in the neurophysiology department can generally be arranged through the forums here on the website.

Can I cancel the injection if it is not needed?

If your symptoms have resolved, either spontaneously or in response to splinting, before the injection appointment comes round then you do not need to carry on with the injection. If you have been wearing a splint at night then try leaving it off for a week and if symptoms do not recur then telephone the SIPC office to cancel. Try to give us at least 48 hours notice if you can so that we can use the space for another patient.

Will it hurt?

You may have had other steroid injections yourself or may have heard stories from other patients of very painful injections. The first thing to be aware of is that not all injection sites are the same. Injections for tennis elbow are not necessarily the same as injections for trigger finger, or a shoulder, and every possible injection site should be considered separately. Injections for carpal tunnel syndrome are mostly no more painful than, for example, having a blood sample taken. However, occasional CTS injections are, for unknown reasons, very painful at the time of injection. This seems to be a random occurrence and nothing to do with either the patient or the person performing the injection, nor is it necessarily an indication of a problem with the injection. Some patients get a period of aching in the wrist and forearm for a few hours to days after the injection – again this is not a cause for concern but if you get this you may wish to rest the hand until it settles. We have asked a large series of patients having injections in the neurophysiology department in Canterbury to rate the pain they experienced during the injection procedure itself on a conventional analogue pain scale where 0 represents no pain at all and 1 to 10 being increasingly severe pain with 10 being the worst imaginable pain (think of being burnt alive). The answers are shown in the following graph.

It is obvious that the vast majority of patients experience little discomfort during the procedure but equally there are, as we knew from anecdotal experience, occasional patients who do get severe pain. We will be looking into these figures in more detail to try an establish if there are any factors which either enable us to predict which patients will have more severe pain, or which might allow us to reduce the incidence of severe pain by changing the way we do things.

What should I do before and after injection?

While waiting for injection, wear neutral angle wrist splints at night unless you have already tried these and do not get on with them. These can be bought in major chemists or online, and can be obtained from the Kent and Canterbury hospital neurophysiology department where you had your tests done. Protective wrist supports sold for skateboarders and ten-pin bowlers are very similar in design and may provide a cheaper alternative. A very small number of patients get so much pain after injection that they may not be able to drive so, if possible, travel by public transport or get someone else to drive to the injection appointment. Based on our experience injecting in the Canterbury EMG clinic the risk of not being able to drive after injection is probably less than 1 in 400. 

There are conflicting views on what you should do after injection and no hard evidence to say that one course of action is better than another. In the absence of any evidence we think the best advice for the present is to return to using the hand normally as soon as any local discomfort following the injection has settled. It is also probably a good idea to continue with night time wrist splinting, at least until the symptoms of carpal tunnel syndrome have resolved or reduced to a trivial level.

What if the symptoms have improved or gone away by the time of the injection?

Carpal tunnel syndrome sometimes improves without treatment or it may respond so well to splinting at night that further treatment is not needed. If you are perfectly happy with the state of your hand(s) one week before the injection date then we are quite happy for you to cancel injection and we will use that appointment slot for another patient. Particularly for patients with fairly mild symptoms you may wish to try the following course of action:

1) Start wearing a splint at night immediately after being tested in Canterbury
2) Book a steroid injection for 6 weeks in advance
3) Continue with the splint for 4 weeks
4) If symptoms have resolved at 4 weeks, leave the splint off for a week
5) At 5 weeks, if you are still not troubled by recurrent symptoms, cancel the injection. Otherwise go ahead and have the injection and resume wearing the splint.

What is being injected?

There are many different steroids available which all share the same core chemical structure (for more detail see the steroid treatment page of this site). In treating carpal tunnel syndrome there is no good evidence to say that one steroid preparation is better than another, nor even evidence to tell us what is the best dose. In the absence of evidence from clinical trials we have chosen to use something which has worked well in previous studies (even though those studies did not compare their choice of steroid with any other option). We will therefore inject 40mg of Triamcinolone Acetate. Some steroid injections are given combined with a local anaesthetic, usually lignocaine (lidocaine), but there is no evidence that this adds anything to either the therapeutic effect or the comfort of the procedure in treating carpal tunnel syndrome so we do not include a local anaesthetic in our injections.

‘Steroids’ have a nasty reputation – will I put on weight, get diabetes or suffer other steroid side effects?

The evil reputation of ‘steroids’ both in medical use and as drugs of abuse in bodybuilders is well deserved. Regular medication with daily steroid tablets WILL inevitably cause serious side effects, including diabetes, weight gain, muscle weakness, osteoporosis, and skin changes… IF you take enough. These side effects are dose related and the higher your daily dose of steroids the more likely you are to get them. It is important to remember however that some steroids are naturally occurring hormones in the body and we all create our own daily dose of steroids from a variety of organs in the body. A deficiency of these chemicals also causes disease. In this context a single dose of a steroid into a wrist is a negligible overall dose of steroids and does NOT cause generalised steroid side effects.

I am diabetic - will it upset the control of my diabetes?

Your blood sugar may run a bit higher or be more erratic for a few days after a single steroid injection so take care with monitoring it. This effect is not generally enough to preclude the use of steroid injections.

What complications are there?

Although a very safe procedure in medical terms, there are well documented, though very rare local complications to steroid injection for carpal tunnel syndrome. These mostly result from placing the injection in the wrong tissue at the wrist and are thus partly dependent on the skill of the person doing the injection. It is for this reason that we get injections performed only by a small group of trained individuals who do many of them. The intention is NOT to inject the trapped nerve itself, nor to put the needle in other important structures in the wrist such as the arteries, veins or tendons. The steroid is supposed to end up in the ‘packing’ tissue between these structures. In order to avoid injecting into a blood vessel the doctor will draw back on the syringe plunger slightly before injection and withdraw the needle if blood is seen. Avoiding the nerve itself is slightly more difficult but if the needle tip touches or penetrates the nerve you will feel tingling or pins and needles spreading into one or more of the fingers, rather like the sensation experienced in the fingers when stimulating the nerve electrically at the wrist when you had the tests done. If you feel this while the needle is being inserted then inform the doctor immediately so that the needle can be repositioned. Nerves will not usually be significantly damaged by a fine needle but injecting steroid preparations into the nerve itself can cause persistent symptoms and we need to avoid this. Injection into a tendon is harder to detect but is likely to be painful. It should be emphasised that these complications are very rare. In published studies of steroid injection for CTS there have been no serious complications in over 3000 recorded injections. At the time of writing we have seen two examples of injection into the nerve and one definite tendon injury in 6000 injections. We have however seen one or two examples of injection into the nerve in patients treated outside our clinics. We have also seen two examples of serious but unusual complications in our own patients (see the treatment section) These two patients suffered problems with the circulation to the hand immediately after injection. One of them already suffered from Raynaud’s phenomenon (in which the fingers go white on exposure to cold and which is a disorder of circulation in small blood vessels) before ever developing carpal tunnel syndrome. Although we hope never to see this complication again – if your fingers become white and painful either immediately on injection or within the next few hours this is a medical emergency. (Explicit instructions will be added here once I have spoken to the vascular surgeons - at present the only suggestion I have seen for treating this is the use of topical glyceryl trinitrate, a vasodilator)

How quickly will it work?

Most patients find that their CTS symptoms improve dramatically within one week after injection, usually within 3 days. In a few cases there seems to be a more delayed effect with symptoms improving up to a month after injection.

How does it work?

The short answer is that we do not know! The original thinking behind the use of steroid injection was the idea that steroids would act as a powerful local anti-inflammatory agent to reduce swelling and inflammation of the tendons passing through the carpal tunnel. However subsequent studies of the tissues in the carpal tunnel have generally shown no evidence of inflammation so this seems unlikely to be the mechanism of action. Some speculation about possible actions of steroids in the carpal tunnel can be found in the section of this website dealing with theories of CTS causatioon..

How long will it last?

Relapse is common after treatment by injection but its timing is unpredictable. About half of the patients who get a good response to steroids are back in the clinic with recurrent symptoms within one year from injection but some patients get very prolonged relief from a single injection – the longest period we have encountered between injection and relapse is 48 years!

I have symptoms in both hands, can they both be injected at once?

Yes! Even if one side had normal test results on the electrical studies, if it feels to you as though it is the same thing affecting both hands then it probably is, and we will be happy to inject both sides if both are causing you significant problems. Conversely however, if one hand is not actually causing you any symptoms we would generally not inject that, even if the electrical studies suggest that it may be developing CTS.

I am pregnant or breast-feeding - is this a problem?

There are no reports of ill effects for the foetus/baby from local steroid injection for carpal tunnel syndrome and one would not expect any given the relatively small dose of steroid involved and the remote site of injection. It is almost certainly safer during pregnancy than the main alternative of surgery. Even so, on general principles if it is within 2-3 weeks of the expected date of delivery one would be inclined to struggle on with splinting only in the hope that the symptoms will improve rapidly after delivery. Steroid treatment in early pregnancy has been associated with an increased incidence of cleft palate but CTS is usually a problem in the last third of pregnancy, We would generally try to avoid injections in early pregnancy.

I am taking warfarin – is this a problem?

Once again there is no documented previous experience to guide us. We have therefore adopted a policy based on common sense and first principles. We will carry out injections with you on warfarin provided your blood test for the warfarin does not suggest that you are taking too much and that you are not actively bleeding from somewhere. In practice this means please get your INR checked or time the injection appointment in such a way that we know the result within a week or so of the planned injection date. We will proceed with injection if the INR is below 2.5. After the injection we will ask you to maintain some local pressure over the injection site for a few minutes and check that there is no obvious bleeding before you leave the surgery. Development of a painful swelling at the wrist during the ensuing 24 hours would be indicative of a problem and you should seek further medical attention.

Interestingly it appears that hand surgery can be carried out safely without interrupting warfarin treatment, Wallace et al (2004) carried out 47 operations on 39 patients on warfarin with no bleeding complications, though they did ensure that the INR was <3.0 before operating. Local steroid injection probably carries a much lower risk of bleeding complications than surgery.

I have previously had a bad reaction to a steroid injection – what should I do

Primarily talk to us about it before choosing a treatment for your CTS. Try to find out as much as possible about the injection to which you reacted. These injections contain different steroids, varying or no local anaesthetic and other chemicals such as stabilisers and preservatives. For example, the commercial preparation 'Kenalog' used in this area contains not only the steroid (Triamcinolone acetate), but also sodium chloride, benzyl alcohol, carboxymethylcellulose sodium, polysorbate 80 and either sodium hydroxide or hydrochloric acid used to balance the pH (acidity). You may have had an allergic reaction to one of the other components of the injection or you may have reacted to one of the synthetic steroids which are not native to the human body. It does not necessarily follow that you would also react to a different preparation so knowing exactly which preparation you have had a reaction to is a vital piece of information.

How will I be followed up?

As you will have noticed from the information here, there are a surprising number of unanswered questions about carpal tunnel syndrome in general and about treatment by local steroid injection in particular. Some of the information provided here only exists because of the kindness of our previous patients in keeping us informed of how they have responded to treatment. We remain very interested in how treatment turns out in every patient who is sent to us with possible carpal tunnel syndrome and there are several ways in which you can help to unravel some of the uncertainties. In respect of local steroid injection the first thing we would like to know is how the symptoms have responded 6 weeks after the injection(s). You can repeat the symptom severity assessment part of the questionnaire here as often as you wish. If you have given us an email address we will in the future try to send you a reminder at 6 weeks but this is not working at present. If it is impossible to feed back via the internet then the doctor who did the injection will carry out a follow-up assessment at 6 weeks, either in person or by telephone. At this point there are several possibilities:

1) Good response – symptoms under control or resolved entirely
2) Good but very short lived response – ie it got much better for a week or three but is already becoming a significant problem again by 6 weeks
3) Partial response – somewhat better but still a significant nuisance
4) No response

80% of patients fall into category 1 and in those we do nothing further until the CTS recurs. Category 2 patients are probably good candidates for carpal tunnel surgery. In category 3) further management depends on you – do you think the symptoms are bad enough to justify surgery? If so then we will probably re-test it and then arrange surgery. If not then we will leave it to you tell us when it has become bad enough to contemplate an operation. Another option would be to try a second injection - existing studies looking at whether it is worth giving two injections in quick succession have shown contradictory results. It is perhaps worth noting that this strategy was used in one treatment trial comparing injection with surgery (Ly-Pen 2005) and that the injection results in that trial were very good. The 4th category is quite rare and may be indicative of the problem not actually being carpal tunnel syndrome. In these cases we will usually review the case again before deciding what to do next – which may well mean a further visit to Canterbury or to another specialist.

In cases where we effectively ‘discharge’ you at 6 weeks after injection then we rely on you to let us know when you relapse. Please do let us know! Even if you do not want to proceed with our line of treatment we would still like to know how things have gone so far. If you do wish to see us again then you do not need to consult your GP again as long as the problem still feels like CTS. You can contact us directly through the website, by email, or by leaving a telephone message on 01227 783048. One of the biggest gaps in our knowledge of what happens to patients is the case who has CTS, has an injection, has a good response to steroids at 6 weeks….. and is then never heard from again! We do not know whether these people are still OK, moved away from the area, died, or just went and got their recurrent CTS treated by someone else – so please feel free to report back to us anytime, even if only to say that it is still OK - indeed we would especially like to hear from patients who remain well now and again. This is best done via the website.

Can it be repeated, and how often?

Second and third steroid injections have been used extensively over the last 50 years but have not been scientifically studied in the same way as first injections. Again, from local East Kent data, it appears that second injections are on average, about as successful as first ones, with some doing better and some worse (Ashworth 2013). The policy we are now employing is as follows:

You may continue treating your CTS with injections as long as you like provided that the following conditions are met

1) They are not more frequent than one every 6 months on average - this is an arbitrary rule (ie a guess by me) because we have to set some kind of limit, not because there is any evidence to support this.

2) The patient fully understands that the risks of repeated injection are unknown - both what might occur and how often - and accepts those unknown risks. This will generally entail a discussion with Dr Bland. We do not at present ask for the signing of a formal consent document but we may consider this in the future.

3) The nerve is not measurably deteriorating – to check this we will want to do occasional nerve conduction studies and if you have not had any tests for more than a year we will definitely want to repeat them before carrying out a further injection. In some cases we may feel that your previous tests are out of date even after 6 months or so. This depends on how bad they were to start with, how severe the symptoms are, and what the rate of progression seemed to be.

You are welcome at any point to decide that you have had enough injections and we will then arrange surgery for you as long as the problem still seems to be CTS.

Revision date - 26th February 2014

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