Kort før jul lancerede jeg en lille julequiz. Se mere her. Baggrunden var, at to af mine venner havde foræret mig en historisk sprøjte som jeg gerne ville have mere information om. Jeg lovede desuden at jeg ville annoncere vinderen den 2. februar, men da vi har haft travlt med at sætte en ny udstilling op på Panum Instituttet havde jeg næsten glemt det.

Denne quiz var langtfra nem da vi ikke havde nogle informationer om sprøjten. Museions gæsteforsker og tidligere overlæge Sven Erik Hansen var den første til at give et bud. Her på den danske blog kunne Sven Erik fortælle at han mente, at sprøjten muligvis var brugt til at behandle hæmorider. Det var et godt gæt, men det lader til at det er odontologiens område vi skal ind på.

Thomas Söderqvist, direktør på Medicinsk Museion, trak i nogle tråde og fik på den måde nogle interessante svar.

Således kunne Frank Manasek give denne forklaring:

This type of syringe was common in dentistry or in minor surgery where local anesthetics (such as lidocaine) would be used. Later syringes of this style were designed to use disposable ampoules of anesthetic, and disposable needles. (This one predates both) The needle on this example is long, suggesting its use in mandibular blocks.

Herefter kunne Alistair Kwan uddybe:

I was just about to write almost the same thing. The last time I asked a dentist about the move away from these, he said that patients are more scared of them because they are big and shiny, and harder to
keep out of sight — convenience and cost of disposables did not play into his decision, though they are primary issues in debates between surgeons, surgical nurses and hospital administrators.

If you compare with today’s common disposables, the plunger design involves a different handhold that increases control through tight spaces and increases pressure on the contents. If you try them out, you can experience how the palm-grip hold is much less subject to little wobbles in the finger and thumb joints. (A high-stability grip for the disposables is to wrap them in all four fingers of a fist, which limits where you can work.)

You can also experience how the palm-grip hold and the lighter two-finger hold are suited to injecting targets at different heights and orientations. You cannot comfortably inject straight down with the
palm grip hold unless you are leaning right over the patient. But your forearm is positioned for easy aiming sideways or forwards or upwards, as into the nerves in the mandibular joint.

For times when you want a pistol or palm grip (e.g. in veterinary medicine), there are handles for disposable syringes. The handles derive from earlier syringes in which they were inbuilt. In recent years (decades?) they have simply had the syringe removed, leaving a hollow or brackets in which to insert a disposable. Similarly with ring grips, now marketed for use by non-medical people with frail hands who need to administer to themselves or family members, and for cake decorating.

Easy disassembly makes cleaning easier but it sometimes owes more to manufacturing processes than concern for scrubbing and autoclaving. A device like this is often cheaper to mass-produce from standard stock than by building all components from scratch. If it goes together easily, it often follows that it comes apart easily as well. Today’s one-way barbed fasteners and sonic welders have of course
cancelled that rule.

Pludselig begyndte vores historie-løse genstand at give et fascinerende indblik i tandlægegerningen. Peter Morris forsatte:

These syringes are still in very common use by dentists in the UK. I don’t recognise the disposables mentioned by Alistair. Personally I always try to avoid the jab if I can which provokes friction between me and the dentist. I would say the needle is a little bit thicker than it appears in the photograph, but it may just be a matter of the scale of the photograph (and the psychological effect of it going into your mouth). A quick look on the web throws up JS Dental Manufacturing Inc of Ridgefield Connecticut. I cannot find out how long it has been in business but it seems well established.

Og tilbage til Alistair 🙂 :

I should clarify a bit though: the common disposables are less stable than the big dental model when used in the mouth owing to how they have to be held. What I originally wrote (in a low-energy moment at the end of work yesterday) was unclear, though I’m sure that your exhibit writers will have no trouble doing better. (I’m now at the start of the day so am more critical of what I write!

Og det kan være at den var den kritiske attitude der fik Alistair til at komme tilbage med en sidste bemærkning:

It might also be worth indicating that some anaesthesia techniques begin with aspirating by withdrawing the plunger to suck a little on the tissue that the needle has entered. This tests whether you are in the right place: the colour of the liquid obtained indicates the extent of blood supply. If you get blood, you know to withdraw the needle and start again. (I find needle-guiding techniques very clever. Other common rules are to locate external markers for guidance, and to hit bone or a sudden resistance change as an indicator for depth. Some markers for mandibular anaesthesia are in the ear which is why the dentist puts his finger there — as target to aim for — while inserting the needle.)

Aspiration is reflected in some plunger handles: they have a ring for the thumb.

It’s more difficult to aspirate with pistol-grip and palm-grip syringes because pulling and pushing require different holds. That may entail having an assistant steady the patient’s head.

Following Peter’s post, I had a quick look at some on-line catalogues and saw that both metal and disposable plastic syringes are sold by dental equipment suppliers.

Det endte altså med at vi fik en mere detaljeret historie end jeg nogensinde havde forestillet mig da jeg først postede den originale post. Og selvfølgelig skal quizzen også have en vinder. Selvom det var et hårdt løb er der en der i særlig grad har markeret sig. Derfor har det strenge dommerpanel (som vil forblive anonymt af frygt for repressalier) besluttet at erklære Alistair Kwan for vinder. Alistair gik længere i sin besvarelse end nogen anden og det blev meget værdsat af dommerpanelet.

Så Alistair, hvis du nogensinde opholder dig i København er du meget velkommen til at komme forbi Medicinsk Museion og få din præmie.

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