Strumento da taglio per la chirurgia della cataratta / Cutting tool for cataract surgery
Strumento da taglio per la chirurgia della cataratta / Cutting tool for cataract surgery
Segnalato dal Dott. Giuseppe Cotellessa / Reported by Dr. Giuseppe Cotellessa
Un nuovo strumento di taglio circolare renderà la chirurgia della cataratta un processo più semplice per i medici, secondo i suoi sviluppatori.
Il dispositivo della Warwick Design, con sede nel Warwickshire, utilizza una lama circolare superelastica in nichel-titanio per praticare un'apertura nella parte anteriore della capsula, una parte dell'occhio simile al cellophane che trattiene il cristallino difettoso. Le lame attuali richiedono ai chirurghi di praticare un foro circolare, una procedura specializzata che può portare a gravi conseguenze se eseguita in modo errato.
Il dispositivo Warwick Design non richiede tale taglio e quindi riduce il livello di competenza necessario ed il tasso di fallimento di questa procedura.
Tutti gli interventi di cataratta richiedono una piccola incisione di 2,8 mm sul bordo della cornea per posizionare lo strumento e praticare il foro. Una volta praticato il foro, il vecchio cristallino viene rotto con una sonda ad ultrasuoni, aspirato con un aspiratore e sostituito con una lente di plastica, che viene ripiegata ed inserita attraverso l'incisione corneale.
Lo strumento a lama circolare è stato ideato da John Stokes, consulente oftalmico britannico presso il Nottingham University Hospitals NHS Trust. L'NHS Innovation East Midlands si è rivolta a Warwick Design per trasformare l'idea in uno strumento pratico.
Lo sviluppatore principale del dispositivo, Andrew Gibbs, responsabile del progetto presso Warwick Design, ha affermato che altri avevano già provato a creare una lama circolare simile, ma nessuno si era concretizzato.
"Erano idee brevettate, ma non erano effettivamente realizzabili", ha aggiunto. "Non esistevano processi in grado di realizzare quei progetti".
Ottenere il progetto giusto non è stato un compito facile. Gibbs ha affermato che è stato difficile decidere il tipo di materiale giusto per la lama ed il suo gruppo ha dovuto dimostrare che la lama fosse sufficientemente piccola e maneggevole da svolgere una varietà di compiti in uno spazio ristretto. La lama deve essere inserita attraverso un tubo di plastica di 2 mm di diametro inserito nell'incisione corneale.
"Immaginare non solo di lavorare attraverso una minuscola incisione, ma anche di strappare un cerchio perfettamente circolare di dimensioni ben controllate – probabilmente più o meno un quarto di centimetro nel cellophane – è molto complicato", ha aggiunto. "Questa situazione è molto peggiore negli occhi pediatrici, in particolare sotto i due anni, perché la capsula oculare è molto elastica e non solo il foro da lacerare è più piccolo, ma anche la lacerazione tende a scorrere radialmente verso l'esterno anziché circolare. Non esiste una grana naturale che dia origine ad una lacerazione circolare".
Il gruppo di Warwick Design ha optato per una lega superelastica di nichel-titanio, per la sua capacità di piegarsi senza deformazioni non elastiche. Il gruppo ha anche stabilito che una lama realizzata in tale materiale avrebbe avuto un'affilatura sufficiente per mantenere un filo tagliente.
Gibbs ha affermato che il gruppo ha iniziato a modellare il dispositivo utilizzando il programma CAD Pro/Engineer.
"Ovviamente si tratta di un dispositivo mobile, quindi abbiamo dovuto modellarlo in vari stati di deformazione e ci sono alcune sfide complesse anche con un software competente come Pro/E", ha aggiunto.
Warwick Design ha collaborato con Richard Allan Medical, un produttore di dispositivi medici con sede a Redditch, Worcestershire, per la micro-produzione delle lame iniziali. Warwick Design ha sviluppato gli stampi in plastica. Un modello funzionante del dispositivo è stato testato su occhi di maiale.
Il Wellcome Trust ha riconosciuto il potenziale dello strumento e sta stanziando circa 300.000 sterline di finanziamenti per renderlo fattibile per la produzione.
"La sfida è realizzare questi dispositivi ad un costo ragionevole, perché al momento gli strumenti per eseguire procedure di lacerazione sono relativamente economici", ha affermato Gibbs.
"Tuttavia, la combinazione di formazione e complicazioni con tale procedura fa lievitare i costi".
Gibbs spera che il suo gruppo perfezioni lo strumento per uso sia adulto che pediatrico nei prossimi due anni e mezzo. "Stiamo già ricevendo interesse da diverse aziende", ha affermato.
Gibbs prevede che tali dispositivi potrebbero essere utilizzati negli ospedali per gli interventi di cataratta entro cinque anni.
ENGLISH
A new circular cutting tool will make cataract surgery an easier process for doctors, according to its developers.
The device from Warwickshire-based Warwick Design uses a circular superelastic nickel-titanium blade to cut an opening in the anterior of the capsule, a cellophane-like part of the eye that retains the failing lens. Current blades require surgeons to tear a circular hole, a skilled procedure that can lead to serious consequences if performed incorrectly.
The Warwick Design device does not require such tearing and therefore reduces the necessary skill level and the failure rate of this procedure.
All cataract operations require a small 2.8mm incision in the edge of the cornea to get the instrument in place to cut the hole. When the hole is cut, the old lens is broken apart with an ultrasonic probe, sucked out with a vacuum and replaced with a plastic lens, which is folded up and inserted through the cornea incision.
The circular blade instrument was conceived by John Stokes, a UK ophthalmic consultant at Nottingham University Hospitals NHS Trust. The NHS Innovation East Midlands approached Warwick Design to turn the idea into a practical instrument.
The lead developer of the device, Andrew Gibbs, design manager at Warwick Design, said others have tried creating such a circular blade before but none came to fruition.
’They were patented ideas but they were not actually manufactureable,’ he added. ’There were no processes that could achieve those designs.’
Achieving the right design was no easy task. Gibbs said it was difficult to decide on the right kind of material for the blade, and his team had to prove the blade was small and workable enough to carry out a variety of tasks in a tight space. The blade has to be deployed through a 2mm diameter plastic tube inserted in the cornea incision.
’If you can imagine not only working through a tiny incision but also tearing a perfectly round circle of well-controlled dimension —probably plus or minus a quarter of a centimetre in cellophane — is very tricky,’ he added. ’This situation is much worse in paediatric eyes, particularly under the age of two years, because the eye capsule is very elastic and not only is the hole to be torn smaller, but also the tear wants to run radially outwards in preference to going round. There is no natural grain that gives you a circular tear.’
The Warwick Design team decided upon nickel-titanium superelastic alloy, because of its ability to bend without non-elastic deformation. The team also determined a blade made of such material would have sufficient sharpness to take and maintain a cutting edge.
Gibbs said the team started modelling the device using CAD program Pro/Engineer.
’Obviously this is a moving device so we had to model it in various states of deformation and there are some complex challenges there even with a competent software like Pro/E,’ he added.
Warwick Design worked with Richard Allan Medical, a Redditch, Worcestershire-based manufacturer of medical products, to micro-manufacture the initial blades. Warwick Design developed the plastic mouldings. A working model of the device was tested on porcine eyes.
The Wellcome Trust has recognised the potential of the instrument and is providing around £300,000 of funding to help make it viable for manufacture.
’There is the challenge of making these devices at a reasonable cost because at the moment the tools to do tearing procedures are relatively low cost,’ said Gibbs.
’However, the combination of training and complications with that procedure puts that cost up.’
Gibbs hopes his team will perfect the tool for both adult and paediatric use in the next two-and-a-half years. ’We’re already getting interest from a number of companies,’ he said.
Gibbs predicted such devices could be used in hospitals for cataract surgeries within five years.
The device from Warwickshire-based Warwick Design uses a circular superelastic nickel-titanium blade to cut an opening in the anterior of the capsule, a cellophane-like part of the eye that retains the failing lens. Current blades require surgeons to tear a circular hole, a skilled procedure that can lead to serious consequences if performed incorrectly.
The Warwick Design device does not require such tearing and therefore reduces the necessary skill level and the failure rate of this procedure.
All cataract operations require a small 2.8mm incision in the edge of the cornea to get the instrument in place to cut the hole. When the hole is cut, the old lens is broken apart with an ultrasonic probe, sucked out with a vacuum and replaced with a plastic lens, which is folded up and inserted through the cornea incision.
The circular blade instrument was conceived by John Stokes, a UK ophthalmic consultant at Nottingham University Hospitals NHS Trust. The NHS Innovation East Midlands approached Warwick Design to turn the idea into a practical instrument.
The lead developer of the device, Andrew Gibbs, design manager at Warwick Design, said others have tried creating such a circular blade before but none came to fruition.
’They were patented ideas but they were not actually manufactureable,’ he added. ’There were no processes that could achieve those designs.’
Achieving the right design was no easy task. Gibbs said it was difficult to decide on the right kind of material for the blade, and his team had to prove the blade was small and workable enough to carry out a variety of tasks in a tight space. The blade has to be deployed through a 2mm diameter plastic tube inserted in the cornea incision.
’If you can imagine not only working through a tiny incision but also tearing a perfectly round circle of well-controlled dimension —probably plus or minus a quarter of a centimetre in cellophane — is very tricky,’ he added. ’This situation is much worse in paediatric eyes, particularly under the age of two years, because the eye capsule is very elastic and not only is the hole to be torn smaller, but also the tear wants to run radially outwards in preference to going round. There is no natural grain that gives you a circular tear.’
The Warwick Design team decided upon nickel-titanium superelastic alloy, because of its ability to bend without non-elastic deformation. The team also determined a blade made of such material would have sufficient sharpness to take and maintain a cutting edge.
Gibbs said the team started modelling the device using CAD program Pro/Engineer.
’Obviously this is a moving device so we had to model it in various states of deformation and there are some complex challenges there even with a competent software like Pro/E,’ he added.
Warwick Design worked with Richard Allan Medical, a Redditch, Worcestershire-based manufacturer of medical products, to micro-manufacture the initial blades. Warwick Design developed the plastic mouldings. A working model of the device was tested on porcine eyes.
The Wellcome Trust has recognised the potential of the instrument and is providing around £300,000 of funding to help make it viable for manufacture.
’There is the challenge of making these devices at a reasonable cost because at the moment the tools to do tearing procedures are relatively low cost,’ said Gibbs.
’However, the combination of training and complications with that procedure puts that cost up.’
Gibbs hopes his team will perfect the tool for both adult and paediatric use in the next two-and-a-half years. ’We’re already getting interest from a number of companies,’ he said.
Gibbs predicted such devices could be used in hospitals for cataract surgeries within five years.
Da:
https://www.theengineer.co.uk/content/news/cutting-tool-for-cataract-surgery
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