Intraneural injection

It does sound possible that that was an intraneural injection, and also quite likely that you did not have CTS at the time. It's hard to give evidence based answers to your questions because intraneual injection is actually a very rare complication of corticosteroid injection for CTS and there are no published series of outcomes, only a scattering of anecdotal reports. The few cases that I have seen personally have eventually recovered but one of them took 3 years and another is still ongoing after about a year. Whether you are now developing CTS as a secondary phenomenon is debatable - if you send me your nerve conduction studies (Jeremy [dot] Bland [at] nhs [dot] net) I will take a look and see if I can make anything of it. Another tactic that might be informative at this point would be ultrasound imaging of the nerve. JB

Thank you so much for your reply Dr. Bland. I have sent the nerve conduction studies and mri result to your email.

An ultrasound was made recently by a physiatrist but unfortunately the result was not significant. Im having a hard time looking for a doctor here in my country who specialized in neural ultrasonography.

Thankyou for those. The first set were interpreted as showing evidence of a left median mononeuropathy affecting primarily motor fibres with the lesion lying at or distal to the carpal tunnel - ie neurophysiologically a 'motor only' carpal tunnel syndrome. This entity is almost vanishingly rare (8 out of 2727 cases in one series) and I have some doubts as to whether it really exists at all. I think all of the reported cases are probably due to diagnostic or technical errors or in a few cases, anatomical variations. In your case I am fairly sure from your description of the original symptoms and these results that you did not have CTS, and as the latest set are entirely normal it seems unlikely that the current problem is CTS so surgery is not really likely to help - though nothing in life is ever entirely certain of course. That still leaves the possibility of neurogenic pain secondary to intraneural injection as this can continue in the presence of perfectly normal nerve conduction studies. By this time I think the acute nerve swelling which can be seen on ultrasound just after the event would have long since settled but if the physiatrist did not see any enlargement of the median nerve now then that is additional evidence against a diagnosis of CTS. I'm afraid there is no evidence based approach to this problem - you just have to experiment with different symptomatic treatments (Gabapentin/Pregabalin, Amitriptyline, Duloxetine, Lidocaine patches, Capsaicin etc) to try and find something that allows you to function until it eventually resolves I think. Rest may help too but is impractical and no-one knows for how long you might have to stop activities so I would be inclined simply to avoid prolonged strenuous use of the hand - including 'strength' exercises - things that keep the hand moving without increasing the carpal tunnel pressure are probably a good bet. Principally you should be advised by your current hand doctor who seems to have the right approach. JB

Hi there,

I wonder if you are still affiliated with this forum? I just wanted to check how things panned out for you in the end with your hand and wrist issue and what worked or you? The reason I am asking is that your story is almost word for word identical to mine and I have not heard anyone else have anything so similar. I am an anaesthetist and I’ve been suffering for six months having reduced my work with similar symptoms having had a steroid injection into my wrist which I believe may have been intraneural but having had normal ultrasound and the conduction studies since. I’m trying to decide where to go with mine at the moment and have been offered carpal tunnel release and nerve exploration by a local hand surgeon, another suggested conservative management. In the meantime I have been having hand therapy with strengthening, stretching and desensitisation which has not really helped and remain very uncomfortable most of the time.

Hoping to hear back.
Best wishes.

Worried dentist was last on in 2017 which is a long time ago but I can try emailing him to see if he is still around. JB

Thank you that would be most helpful. It would be useful to know how things progressed.

I've emailed 'worrieddentist' today - lets see if the email address is still current. JB

There's been no reply from 'Worrieddentist" I'm afraid. Presumed out of contact. JB

Hello Dr. Bland,

Thank you for reaching me out thru my email. Im sorry Ive only seen your mail today.
Hi Anaesthetist. How are you now? I hope you are doing ok. I will share to you my experience.

Ive decided not to go surgery and give chance to my body to naturally heal. Early years after injury is very hard for me because of the pain and weakness on hand grip. But slowly the nerve healed. Two to three years after the injury the symptoms improved. My strategy is to always be conscious on my hand position. If possible always maintain neutral hand position. I repositioned my body and my hand during dental work so that my hand is position straight. Ive given up my oral surgery practice because the injury had affected my firm hand grip. But surprisingly my hand fine movement pen grasp is not affected. Now my dental practice focuses on esthetic dentistry.

After 5 years, my condition now is good. My injured hand still have signs of muscle loss. The burning, pain, pins and needles, significant numbness sensory symptoms are now gone. I only have very minor numb feeling on the medial area of my index finger. I am still taking pregabalin 75mg with vit b complex every day. Now I can play again my guitar and ride my bike without the consequence of previous injury symptoms after.

Doctor Bland may I know your thoughts on long term medication of Pregabalin.

Thank you so much doctor.

Thanks for getting back to us. I've emailed 'Anaesthetist' too. I'm glad you seem to have achieved a satisfactory result.

I think we still don't really know what the diagnosis is in your case. I think CTS is unlikely but the prolonged efects of an intraneural injection remains a possibility, as does a problem at a completely different site such as a cervical root. Most of the things which it might be are disorders that might not necessarily get worse with time so the subsequent clinical course of improvement would fit with quite a few diagnoses.

I'm not aware of long-term pregabalin being a particular problem but as a generally anti-long-term medication person my own inclincation would be to try withdrawing it slowly now and again to see if it's really still necessary. JB

Hi both - thanks for your replies. I and thrilled to hear that over the last 5 years things have shown significant improvement. It must have been a battle for sure. I'd be keen to have your perspectives.

Regarding my story, I hope you don't mind me giving some detail as it's been pretty complicated. I developed numbness in my left (non-dominant) middle finger and a little in the index finger a year ago. Prior to the symptoms developing in lockdown I had been doing more daily circuit gym exercises like press-ups, then went on holiday in a camper van driving (manual shift) for 2 weeks as well as paddle boarding. No trauma and no neck pain. During this time I wore a wrist brace every night and much of the day on the advice of a colleague. On the last day of my holiday I woke with numbness in all fingers (anterior aspect only) and into some of the forearm. I had no pain or stiffness, but my hand felt a little less coordinated when playing the piano (only occasionally) for example.

I saw a neurologist who did MRI head and spine. Only thing found was a C5/6 osteophytic bar which was not neurally compressing. NCS showed normal sensory nerves (no latency). The motor on left median had 50% amplitude action potential to that of the right, but still both were in normal range. I had normal Phalen’s and Tinnel’s but pressure over the carpal tunnel worsened the numbness. He thought it was Carpal Tunnel Syndrome (albeit not classic as not at night/shaking wrist etc and normal sensory ncs). He suggested a steroid injection.

I saw a GP who injected me with 0.5ml Kenalog (no local anaesthetic). Immediately on insertion of the needle I had electric shock sensations into my thumb, 1st webspace and index finger, followed by profound numbness there. He told me not to worry as he withdrew the needle a little before injecting and it just showed him he was in the right space. I thought he had hit my nerve. After 15 mins the profound numbness receded to leave just mild numbness. Over the next couple of days a deep aching pain started (like toothache) in my wrist and thenar eminence. It was keeping me awake. I stayed in a splint which only helped a little. I saw a hand surgeon who did repeat NCS, wrist ultrasound and MRI. The NCS were unchanged (still just the motor half amplitude but still normal range and normal sensory nerves, nothing higher in the brachial plexus obvious). The ultrasound of the median nerve/carpal tunnel was normal, no sign if steroid (this was a few weeks after). A ganglion was picked up, confirmed on MRI as originating from the Trapezium/Trapezoid join and travelling distally into the thenar eminence, 9mm in diameter and travelling 1mm away from the digital branch to my thumb. (Not in the carpal tunnel per se but near) The surgeon was unsure of the significance of this ganglion. He also thought that an intraneural injection was extremely unlikely given the investigation findings. He suggested options to either have surgery with removal ganglion, median neurolysis and carpal tunnel release to fully decompress the median nerve and look for any steroid, vs a conservative approach with hand therapy and analgesics - suggested that conservative therapy was best. I started pregabalin and nortriptyline to help me function and sleep. I have to take 3 months off work. I was in a splint most of that time. It seemed wrist ext/flex stretches and nerve gliding exercises did not help - often making it worse. I tried some wrist strengthening exercises too through the hand therapy team.

Within a few months the skin on the anterior side of my wrist where I had the steroid injection thinned and became depigmented. I was told this was the steroid and reassured that it would likely recede with time. I also developed dysaesthesia in this area of my wrist and a very strong Tinel’s sign 1-2cm above where the steroid needle was introduced. The surgeon said that this required desensitisation which I persisted with despite it feeling it was making it worse and occasionally intolerable. It became impossible to wear a watch or a cuff as this would make my wrist ache and feel a very uncomfortable sensation. I tried a ganglion aspiration - the local anaesthetic first made my thumb go completely numb (where I get my current symptoms) which made me think that the affected nerve must be nearby! It did not really improve my symptoms, but the radiologist did not manage to get much out of it - probably reduced its size by a half - it has now grown again to its pre-aspiration volume.

A year on, I am back to work full time and have stopped the pregabalin and nortriptyline some months ago due to side effects (they made no difference anyway I think). Overall I would say my symptoms are 30% better. I am sleeping but I am finding life a real battle as I have never had a day without symptoms - thumb and index numbness (still mild), and intermittent deep toothache pain in wrist radiating into my forearm which comes with no rhyme nor reason and can last an hour or so, but also provoked occasionally by things like driving. When it ramps up it stops me in my tracks and I feel sick with it. I am trying to push through and stay positive. The wrist skin is still pale and thin but may have improved a little. The dysaesthesia is again mildly better. I still have significant subjective stiffness in my left hand and wrist (although I gather my range is good) and the ache as stated with the fluctuating thumb/index numbness.

I was referred to another hand surgeon as a second opinion for ongoing symptoms. She thought the ganglion was the main causative aetiology of my symptoms and that a neural injection was extremely unlikely (despite the timing of the pain being with the injection). She felt the steroids could have flared up the pain, but the numbness initially being the ganglion. I asked if she thought the ganglion could have been caused by a deep injection hitting the T/T joint - she felt unlikely. I asked if it could be tethering of the median nerve from trauma at the site of the injection. She fully examined me and noted my strong Tinel’s signs just proximal to my injection site but was not sure of the significance. She noted my numbness worsening with pressure over my thenar ganglion, but negative Phalen’s. She has repeated the wrist MRI and NCS. The MRI was the same - ganglion, same location in thenar eminence root from the carpals and size similar, saying not neurally compressive (but a static scan and 1mm away from the nerve). NCS were the same again as each time before, including pre-injection. This time the Neurophysiologist did EMG and noted “mild denervation” of the AP muscle (normal dorsal function) suggesting median nerve pathology around/below the carpal tunnel. I do not feel that my thumb abduction is significantly weaker but have noticed a possible dimple in the AP muscle region of the thenar eminence which may represent a localised wasting.

So I am now waiting to have my follow-up with the new hand surgeon next week who will review my investigations. I suspect the options will be ganglion removal +/- carpal tunnel release +/- neurolysis vs ongoing conservative management and seeing if things get better with time. (These were the choices offered by the original surgeon a year ago).

In the meantime I’ve restarted the carpal tunnel stretches/nerve glides and strengthening exercises for my wrist as well as desensitising. It is very time consuming and I’m not sure if it’s beneficial (a ganglion can grown with more wrist movement). I’d be keen for your advice Dr Bland and thank you very much for your kindness and support on this very helpful website.

It's a tough one. I think the whole story is coloured by the initial diagnosis of CTS which most people then seem to have accepted without much question. My own guess is that if repeated detailed NCS have been persistently normal over a year and the ultrasound imaging shows no focal nerve enlargement then the initial diagnosis was probably wrong. That depends of course on the NCS and u/s being done by people who know what they are doing but I assume that is the case.

Further things against it being primarily CTS are the relatively sudden onset, numbness above the wrist and lack of response to steroids. The cervical MRI may have missed something. Loss of amplitude of the thenar motor potential might make you wonder about thoracic outlet syndrome. CNS disorders such as MS are probably unlikely to be missed by the MRI. The ganglion sounds as though it might conceivably compress the recurrent motor branch of the median nerve sometimes but that would not give you numbness in the forearm.

Starting from that point and assuming that there is some other explanation entirely for the original symptoms we then complicate the picture by trying injection. Taking the description at face value it sounds very much as though the original needle insertion did indeed hit the nerve. Usually you would get away with sticking a needle in a nerve without doing very much lasting damage, you might sever a few axons but most nerve fascicles would slide aside. The needle was then repositioned but it's hard to be sure whether it was moved enough to get away from the nerve because by that point you already had the symptoms that would warn you of intraneural injection. Faced with persistent numbness at that point I would have abandoned the procedure and not injected anything but it seems they went on and injected what sounds like a half dose (20mg) of triamcinolone. Two surgeons have subsequently said they thought that was probably not intraneural but I think it's impossible to be sure. You can sometimes see the problem on an ultrasound examination done within days but I don't know either the timing of your scan nor whether they would know what to look for. I may possibly be the only person who has ever seen a median nerve ultrasound scan within a few days of an intraneural injection as most places would have too long a waiting list for imaging to have the chance to see it and people who do the imaging under ultrasound control and therefore see the images live do not of course inject the nerve. If it was not even more painful during the infiltration of the steroid that is perhaps some evidence against intraneural injection.

Most of the intraneural injections we have seen have settled in the long term. Pain has generally been the most persistent feature rather than loss of function. All of our cases have been in nerves that are already abnormal to start off with because they had CTS so they had abnormal NCS anyway. I don't know whether injecting a normal nerve because of mistaken diagnosis would then produce nerve conduction abnormalities - it might but I don't think anyone would want to do it experimentally to find out in a real patient, and animal and petri dish experiments are not the same thing really. Susan Mackinnon did an experimental animal study in 1982 but only evaluated the nerve after injection with histology. All told I think it it relatively unlikely however that this injection was placed intra-neurally. I can theorise about other pathophysiological mechanisms that might fit this story - for example if you had a small persistent median artery and this was injured by the needle you might well get a small haematoma in the neurovascular bundle and the acute symptoms you describe. This would get re-absorbed fairly quickly and probably leave no visible trace on ultrasound.

The skin changes are typical after injection and do usually resolve slowly if the injection is not repeated. Not many people are seriously bothered by them.

I can't tell whether you should do anything about the ganglion without seeing it myself I think but if you decide to go ahead with surgery for CTS they might as well deal with that at the same time.

The really hard decision here is whether to decompress the carpal tunnel. Personally I would look at the diagnosis again very hard before resorting to surgery, as there is clearly no urgency to protect the nerve from progressive damage if the NCS and imaging are still normal, so I would want to be as sure as possible that we had not missed anything else before taking a knife to it. JB

Many thanks for your reply. I thought I’d email you my NCS and EMG from a month ago. I would be interested for your opinion if you feel able. I have also copied MRI images showing the larger thenar ganglion originating from the trapezium/trapezoid joint they feel is the culprit.

I spoke with the surgeon yesterday who suggested it was not carpal tunnel syndrome (or any higher cause since no neck or shoulder pain) - the thenar ganglion was likely the cause of my symptoms and wanted to list me for surgery involving carpal tunnel release (mainly to gain access to the ganglion safely) then ganglion removal. She said it was in an unusual area with a lot of “clockwork” so with some risk, albeit being a hand surgeon she is trained to know and avoid relevant structures. She feels nobody would be sub-specialised in removing from this area as it’s quite unusual. It would be a first thenar ganglion for her, albeit having removed ganglia elsewhere. The risks were explained including likely permanent scar numbness or pain, risk of injury to local structures, small chance of worsening pain or CRPS.

My numbness and aches fluctuate in severity. The numbness mainly is in thumb and fairly mild but pretty much constant then occasionally gets worse for a day or two. She said removing the ganglion could help take pressure off the nerve so the fluctuation would go but given the baseline it is there all the time it would be better to get on with it sooner. I do have a dimple/possible wasting of my APB muscle (I emailed a pic). I wonder if based on these NCS tests you’d be in agreement or would feel no urgency to remove the ganglion and just give more time?

Thanks in advance for your help.

No sign of any new email as yet. I remain uneasy about the idea of sensory symptoms in the forearm caused by a ganglion in the hand. JB

Thanks Dr Bland. I’ve just sent them again. Not sure if going into a Junk Mail folder?

I'll have a search this week sometime - still catching up after being away for two weeks. JB

Got that email now - came through 11th July but it's taken me until now to catch up with those emails. The ganglion is very clear on the MRI but it's hard to see how that could cause forearm symptoms. The NCS results are normal apart from the previously noted asymmetry in the amplitude of the thenar motor potentials - no evidence of CTS and there is no obvious ulnar nerve lesion but that's really as far as they have gone. Hard to know what to make of the dimple as that thenar profile will depend very much on which muscles you are activating. I suppose in theory the ganglion could be affecting the recurrent motor branch of the median nerve but it doesn't seem to be deteriorating. I doubt if ti would do any harm to remove the cyst but if that was my wrist I would be inclined to preserve my transverse carpal ligament if possible. JB

Many thanks Dr Bland. Would there be any evidence here for this being a median needle stick injury from the steroid injection? Would your advice be to leave it and give it time or have an intervention like neurolysis if that were the case? Thanks.

Sorry about the slow reply, I've been teaching all week. I don't think there is any evidence either for or against needlestick injury in what we've seen there. As your median nerve is in pretty good shape physiologically I don't think there is any great hurry to cut your transverse carpal ligament so you can afford to take your time and think about it. JB

I'm locking this thread because it's attracting spam. You can always start a new one. JB