Citanest and Prilocaine

From Chris Wheeler

Those who prefer to use 2.2ml dental cartridges when administering a local anaesthetic will be well aware that lignocaine is no longer available as a plain solution.  Lignocaine with adrenaline (usually 1 in 80,000) continues to be available from the usual suppliers.  There has long been discussion about the wisdom of using vasoconstrictors with end arteries such as the toes.  An alternative to lignocaine is prilocaine 3.4% plain (Citanest 4% dental).  Unfortunately as you may know the sole supplier of this in Australia, Dentsply has been unable to have a sufficient supply to meet the needs of Australia’s dentists and thus podiatrists Dentsply ph no is: 1300 552 929 re order no 00804 for prilocaine 3.4% plain, When available, prilocaine  is sold in a box of 100 cartridges.  

The reason for this drought as I understand is that the Australian market for lignocaine plain was too small for that manufacturer (Astra Pharmaceuticals) to continue.  Dentsply apparently moved their manufacturing base for prilocaine from Australia to America.  As I found out some months ago, supplies of prilocaine were to return to normal in July of this year after some three months absence.  Unfortunately the back orders exceeded Dentsply’s ability to supply same.  This situation caused me, as I was reluctant to return to drawing up solutions of lignocaine in the more traditional way, to source another supplier.  My investigations have taken me to Henry Schein Regional, (8 Michael St, Brunswick. Ph 1300 360 324).  They sell mepivacaine hydrochloride 66mg in 2.2mls (otherwise known as Scandonest 3%)  (The re order no of Scandonest 3% plain through Henry Schein Regional is ST 4049). Without vasoconstrictors, mepivacaine has a similar action to  prilocaine and lignocaine is the same but interestingly, the Scandonest 3%, which is delivered in boxes of fifty cartridges is cheaper (say $70 for 100 where as Citanest is $110 per 100 as was lignocaine.  It is a requirement of Henry Schein Regional and Dentsply that an aspiring purchaser must register as an account holder.  This they do to (supposedly) ensure that you have the legal authority to use this medication.  

It is noteworthy that I expect that I shall continue using mepivacaine instead of citanest when the citanest drought is resolved because I estimate that one third to one half of all patients for whom I injected citanest reported some ongoing paresthesia around the site of the injection and sometimes distally in the toe.  This has continued for at least one month in one case.  One patient developed localised necrosis at the injection sites.  I raised this matter with a local dentist who said that it is known in dental literature that tissue toxicity can occur with prilocaine. It is assumed this is caused by the relatively high strength of this form of prilocaine that is causing these problems.  It is also worthwhile asking to receive a copy of their most recent catalogue which, whilst currently out of date, for podiatric needs is quite adequate provided allowances are made for changes in price.

Needle Perforation Study

Just a bit of extra shameless self promotion. The recent abstract and presentation from NZ Australasian conference. All in the cause of science.

Watch out for the big download: 7.5MB
Needle Perforation Powerpoint
Abstract:

Conference Abstract.doc

Hope it is of use.

Matt    

Plantar plate paper from AJPM

I have had a few requests lately for copies of my paper on plantar plate tears. So to save some hassle I am putting it up for easy download in pdf format.

AJPM plantar plate.pdf

Sorry for the mercenary self-promotion.

Matt

Formalin and Hyperhidrosis

Basically Formalin is cytotoxic and with its strong affinity for water will enter the sweat gland and from my understanding denature the cell walls. Regrowth occurs eventually.

I normally apply formalin for treatment of pitting keratoloysis which, in my opinion, should be the main stay of treatment for all cases.

It is applied once daily at 10% concentration for 1 week. Depending on results the patient can continue on for a further week or two if necessary. No doubt the condition will recur but probably not for another 6 months. Hence it is repeated as necessary.

Formaldehyde can be quite irritating to the skin. This varies from the type of skin it is applied to, to the genetics of the individual. Axillae I have never tried it on but I assume it would be more irritating . I would suggest daily applications at 3% for a week and then see how it goes. If it does nothing then try twice daily for a week. If still no significant irritation but not enough effect then bump it up to 10% and try the same process again.

Don’t need to wipe off just let it evaporate. Just apply with gauze or cotton wool. Tried to avoid regular contact with your fingers as it will dry them out.

My first Formalin Success story (yet to be confirmed)

I am not sure that anyone really cares (Matt are you the only one who reads these?) but I had my first formalin success story, but not before some drama.

2 weeks ago, had a young 10yr approx old male. a 5cm coin size VP just prox. to L 1st MPJ plant. Following debridement, Moved on to an HD on R'f, and within a minute I look up at him, pale as a white wall. Before I could lay him down in my chair, the poor little fella was sick. While his colour returned instantly, I was left with a lovely mess (and smell !) to clean up, and ended up running about 30 min late for next appt, while his mother and I made sure he was alright before standing up !! I didn't care, rather was wrapped he was alright when we left. He didn't give any warning signs what I was doing was hurting. No wincing or whinging. Meanwhile his mother was in fits of laughter.

Following the little drama, I felt terrible, but he was non-fussed. He was consequently fine, and today his mother phoned to say the wart had dropped off following 2x daily 1 min soaks of formalin. She was happy, but I am yet to see it again, so cannot confirm that it has completely resolved. I will keep you posted !!

Copy of summarised diabetes paper from the Ark.

Here is a copy for you to laugh over!

Monofilament Revised Document.doc

Be kind,

Matt

Haemostasis in Wart Curettage

I have been speaking to a few podiatrists lately about their experiences with wart curettage and I have noted that getting adequate haemostasis (bloodless field) during the procedure is proving difficult. I noted these problems myself when I first began doing these procedures and gradually worked out what needed to be done to achieve a bloodless field. I have outlined the procedure below:

I have also shown the approach I take to doing tibial nerve blocks (which is a common approach by many). The patient is layed prone and I have just recently begun using liquid nitrogen prior to the injection to reduce needle pain (another common trick). Aim for the posterior aspect of the medial malleolus approximately 1-2 cms above the distal aspect of the malleolus. Obviously you do not always have to do a tibial nerve block for wart curettage and indeed I generally lean towards local infiltration to expedite the process of anaesthesia.



The first stage in exanguanating the limb is putting a towel around the leg. This is to reduce the pain of a highly inflated cuff and distributes pressure from the cuff more evenly. The pneumatic cuff is then placed over the towel (mid-calf) but not inflated.



Next a crepe bandage is wrapped around the foot to "milk the blood" from the area.



With the crepe bandage still in place the pneumatic cuff is inflated (I usually just inflate to the maximum pressure of 300 mm/hg) and then the crepe bandage is removed. The cuff will feel tight but this is much better than all the other options you have.

The foot with the crepe bandage removed should then appear white and if you look at SVPFT it should be very slow or non-existent.



I hope that helps a few people.

Matt