Hair transplant instrument and method

Abstract

An instrument for use in hair transplant surgery has a hollow handle (1,2, Fig 2) containing an electronics assembly having a microswitch 9 coupled to an axially displaceable chuck assembly 15, 22. Th

Description

Technical field [oooi]. In a hair transplant procedure, a practitioner transfers hair follicles as follicular units from a hirsute donor site of the patient’s body to a bald recipient site. Each follicular unit is removed, from the donor site, by the practitioner making an incision adjacent the follicular unit to be extracted. A sharp implement such as a micro-punch is used to make the incision and various techniques and apparatus may be used to extract the follicular unit to minimise the risk of damage to the follicle. The follicular unit is then prepared for implantation at the recipient site. The prepared follicular units are then implanted into an incision at the recipient site. Implantation involves making an incision using a scalpel before insertion of the prepared follicle unit.

[0002] , The number of follicular units implanted at the recipient site needs to be matched by the number of follicular units to be extracted at the donor site. The number of follicular units to be implanted per square centimetre (follicular density), at the recipient site will vary according to the characteristics of the particular patient in order that the hair transplant will appear natural. To this end it is necessary to determine the area of the recipient site with precision. From the recipient site area, the number of donor follicular units required can be determined. This is an important factor in determining how well the transplant surgery is performed. Extracting donor follicular units in excess of the requirement is wasteful and subjects the patient to avoidable discomfort as well as invoking unnecessary labour from the practitioner. Extracting fewer follicular units than are required will necessitate the practitioner returning to the donor site causing avoidable delay and increasing patient discomfort. Prior art

[0003] , ES1247389 discloses an incision counter instrument for hair transplant surgery. The instrument comprises a clutch assembly operable to grip a blade. The clutch assembly is retained in a hollow body which serves as a handle to be manually gripped by the practitioner. The hollow body provides a chamber in which is contained an electronics assembly including; an electronic counting unit having a digital display and, a chemical cell, or battery, to power the electronics. In use the practitioner will apply a force to the blade to produce an incision either to extract a follicular unit or to receive a follicular unit. Each time a force is applied to the blade the electronic counting unit increments a recorded count of the number of incisions by one and, displays this number on the digital display. The electronic counting unit is provided with an on-off switch, switching the on-off switch turns the instrument on and off and restarts the count from zero.

[0004] , ES1247389 is able to provide a count of the number of times force is applied to the blade, and therefore an estimate of the number of incisions made and correspondingly, the number of follicular implants extracted or implanted. The present invention aims to provide an inexpensive, simple to use instrument and process. The instrument will preferably be able to accurately count the number of incisions made and, provide an accurate estimate of the incisions needed in the area of the recipient site. The instrument may thereby increase accuracy, reduce waste of a limited follicle resource (which at present is a fundamental shortcoming in the industry) and minimise discomfort to the patient while minimising the labour imposed on the practitioner. Summary of the Invention First aspect

[0005] , An instrument for hair transplant surgery comprising an elongate handle with a front end and a rear end; a chuck assembly mounted into the front end of the handle to removably hold a tool; an electronics assembly in a chamber in the handle including a sensor mounted to sense a force applied longitudinally to the chuck and responsive to sensing the force to increment a counter and a display arranged responsive to the counter to display the integrated count; characterised in that the tool held in the instrument chuck comprises a stamp, said stamp having a shaft for engagement in the chuck, and a foot bearing a marking surface able to carry a charge of ink to mark the periphery of a predetermined area of skin.

[0006] , Preferably the chuck is retained in the handle by means of a magnet. The magnet may secure the chuck assembly against a sensor mechanism. The sensor mechanism may be a microswitch including a resiliently deformable element. A microswitch is preferred over alternative forms of stress / strain sensor because it provides a positive tactile feedback to the practitioner when a force exceeding a predetermined force sufficient to close the switch is applied. The microswitch may also be selected to provide an audible signal, such as a click, to indicate when the switch closes.

[0007] , k brake is urged into engagement between the magnet and the chuck assembly in order to prevent relative rotation of the chuck assembly and the handle and facilIitate tightening or loosening the chuck by relative rotation of a chuck core and the handle. By pulling the chuck assembly forward relative to the handle the brake may be disengaged allowing the relative radial position of the chuck assembly and handle to be altered. This feature is particularly useful when a scalpel tool is substituted for the stamp tool in the chuck assembly.

[0008] , The chuck assembly may comprise a core supporting a plurality of jaws. The core is arranged to move axially relative to a surrounding sleeve in order to open and close the jaws. The jaws are formed from radially extending slots in a front end of the core. The core may be exchangeable in order to present a range of slot sizes or other jaw configurations in order to accommodate a range of different tools.

[0009] , The electronics assembly preferably includes a correction switch manually operable to subtract one from integrated count to correct erroneous operation by the practitioner. [ooio]. Preferably the stamp tool comprises a foot and a shaft. The foot and shaft may be formed from a resilient wire structure defining the periphery of the stamp area, extending from the shaft. A portion of the shaft may be flat in order to facilitate secure engagement in the clutch assembly. The stamp is preferably fabricated from a material readily susceptible to being sterilised for use in a surgical procedure, for example stainless steel. The stamp preferably has a polygonal periphery defining the stamp area. Preferred polygonal shapes include any one of triangular, rectangular, hexagonal and a four curved sided shape. [oou]. The stamp may be provided in any of two or more sizes to be exchanged by the practitioner according to the size, contour and peripheral shape of the recipient site to be measured. A stamp of smaller area may be used to measure a recipient site of small area or to measure the area of a highly contoured recipient site. For these purposes highly contoured means highly curved in a direction perpendicular to the skin surface or not flat. A relatively small stamp will also be helpful when measuring a recipient site with a highly curved or irregular periphery. A small stamp may be a regular triangle with an area of 100mm2 while a large stamp may have a triangular shape and an area of 400mm2 or 900mm2. The large stamp may have linear dimensions which are an integer multiple of the size of the small stamp in order to facilitate tiling the area to be measured. It will be noted in this example that the stamps all correspond to equilateral triangles having sides of one, two and three times the side of the smallest stamp. Second aspect

[0012] , According to a second aspect of the present invention there is provided a method of measuring the area of recipient site of a patient during hair transplant surgery comprising the steps of: providing an instrument having a handle supporting a chuck in which a stamp is engaged; charging the stamp with a charge of ink; applying the stamp to a portion of the area of recipient site of a patient in order to mark the skin with the ink such that a sensor of an electronics display in the instrument is actuated to cause a counter circuit to increment a count of one and display the integrated count visibly on a screen; a subsequent step of applying the stamp to the unmarked recipient site of the patient with sufficient force to cause the counter to increment a count of one; repeating the subsequent step until the whole of the bald area to be subject to hair transplant is marked with the stamp.

[0013] , To determine the area of a bald area of skin to receive a hair transplant the practitioner selects a suitably shaped and sized stamp, according to the degree of contour of the area, the peripheral shape of the area and the overall size of the area.

[0014] , The stamp is calibrated by inking the stamp, for example on a pad of ink and applying the stamp to a sheet of paper or similar substrate. The ink is preferably clean, non-toxic and capable of being readily wiped or washed off of skin. The practitioner then marks the interior of the stamped area with a writing instrument such as a pen to represent the number of incisions to fill the area.

[0015] , Having calibrated the stamp, the practitioner will apply the stamp to the recipient site, each application being as nearly as possible touching adjacent to a previous application until the site is substantially filled by the resulting stamped pattern. Upon each application the counter will increment by one and the sum of the applications will be displayed on the display. A simple calculation will allow the practitioner to calculate the total number of incisions and follicular units required to be transplanted.

[0016] , If the stamp is misapplied resulting in an erroneous count the count can be corrected by manual operation of the correction switch.

[0017] , After marking the recipient area as described above the practitioner removes the stamp from the instrument and replaces it with a scalpel. The scalpel is preferably partially shrouded by a disposable sleeve of tubing which extends from the chuck assembly along a shaft of the scalpel to ensure that the application of the exposed scalpel blade to make an incision will apply sufficient force to increment the counter when the end of the sleeve distant from the chuck assembly engages the patient’s skin. The instrument is then used to make incisions removing a number of follicle units from the donor site until the integrated count of removal incisions equals the number of follicular units calculated for the recipient area.

[0018] , The follicular units extracted from the donor site are prepared for insertion at the recipient site. The practitioner then uses the tool to make incisions at the recipient site using an appropriate tool mounted in the chuck. The instrument can be used to count incisions made into the recipient site to receive the follicular units.

[0019] , Brief description of figures

[0020] , An embodiment of the instrument and method will now be described, by way of example only, with reference to the accompanying figures, in which: figure 1 is a plan view of the instrument; figure 2 us a side elevation of the instrument; figure 3 is a sectional plan view; figure 4 is a SW isometric view of the stamp; figure 5 is a SE isometric view of the instrument with a top part of the housing removed and the stamp tool replaced with a scalpel tool; and figure 6 is a detail showing the radial splines of a brake formed on the clutch assembly and the magnet. Detailed description of figures

[0021] , The instrument comprises a bottom housing part 1 and a top housing part 2 each shaped so that when secured together they form a generally cylindrical shape which provides an ergonomically effective handle. The assembled housing parts 1,2 form an internal chamber 8 which houses an electronics assembly including an LED visual display screen 3, circuit board 4, a battery 5, an on off switch 6 and a reset switch 7. The screen 3 can be viewed through a window in the top housing part 2. The on off switch 6 is manually operable to turn the instrument on and off and zero an integrated count displayed on the screen 3. A reset switch 7 is operable to subtract one count from the screen to correct an erroneous count. The switches are recessed to mitigate the risk of unintentional operation.

[0022] , To the front of the circuit board is mounted a magnetic assembly including a microswitch 9 having a plunger 10 urged towards the front of the instrument by a compression spring 11. The plunger irrotatably supports a cylindrical magnet 12 covered by a rotation brake cap 13 irrotatably secured to the magnet. The rotation brake cap is generally cylindrical and has a front facing surface formed with equi-angularly spaced radial splines 14 spaced at fifteen-degree intervals. The magnetic assembly is secured against axial and rotary motion by features (not shown) formed on the housing parts.

[0023] , k chuck part 15 of a chuck assembly has a brake part 16 formed with a rearwardly facing generally circular surface formed with radial splines 17 complementary to the splines 14. The brake part 16 is magnetic or ferromagnetic in order to be attracted magnetically towards the magnet 12 causing the splines 14 to engage with the splines 17 and thereby prevent relative rotation of the chuck part and chuck assembly with respect to the magnet assembly.

[0024] , In a variant of the instrument the rotation brake cap 13 and the brake part 16 may use complementary axially extending splines or complementary interengageable projections and sockets or any other cooperating structures suited to prevent rotation between the brake parts and be axially displaceable to enable rotation. The cap 13 and brake part 16 may be integrally or separately formed with the respective magnet and chuck part.

[0025] , The chuck part 15 includes a cylindrical element 18 extending coaxially from the brake part 16 which has a front facing axial bore hole 19. The chuck part 15 locates into a forward part of the chamber 8 so that a gap 20 is provided between the leading edge of the chuck part 15 and a shoulder 21 forming the front end of the chamber 8 whereby the chuck part 15 can be pulled forwards in the chamber sufficiently to disengage the splines 17 from the splines 14.

[0026] , k chuck core 22 comprising an elongate cylindrical shaft with a threaded rear end is screwed into the bore hole 19. The chuck core 22 is closely received into a chuck sleeve 23. The front end of the chuck core is divided into four jaws by four radially extending slots 24. The front end of the chuck core is enlarged to provide an inclined annular shoulder 25 which when the core is screwed tightly into the bore hole 19 bears against the front end of the sleeve to apply a compressive radially inward force to the jaws such that a stamp tool 26 or scalpel 27 can be securely clamped into the instrument. A nose piece 28 is provided encircling the front of the clutch core and sleeve and has features 29 projecting radially inwards to engage in the slots 24 to facilitate tightening and loosening the clutch core.

[0027] , The stamp tool 26 is formed from stainless steel wire and has a shaft 30 which has a portion 31 flattened to improve engagement when secured into the clutch. The shaft 30 is bent to form a foot 32 in the shape of a skeletal equilateral triangle lying in a plane perpendicular to the shaft 30.

[0028] , In order to determine the area of a recipient site the stamp tool 26 is secured into the clutch by first sufficiently unscrewing the core inserting the flattened portion into two radially opposed slots 24 and then tightening the core to close the slots 24. The brake is engaged by the magnetic attraction to prevent relative rotation of the clutch assembly and housing during this step. The practitioner then applies the foot of the stamp to an inked pad bearing a washable ink and applying the stamp to a first part of the recipient site. The force with which the stamp is applied causes the chuck assembly to move towards the rear of the instrument against the bias of the spring 11 until the microswitch closes and causes the circuit to add a count of one to the display 3. The practitioner then removes the stamp and reapplies the stamp to an area of the recipient site immediately adjacent (ie touching) the area marked by the ink applied by the first application in an otherwise similar manner causing the instrument to increment the count displayed by one. This process is repeated until the entire recipient site is tiled with the pattern produced by applying the stamp. The practitioner may recharge the stamp with ink from time to time as necessary.

[0029] , Before or after applying the stamp to the recipient site the practitioner will calibrate the stamp by applying the stamp to a substrate such as a piece of paper. The area inside the stamped pattern is then marked with a writing instrument in a pattern representing follicular unit insertion positions in order to represent the number and position of incisions to be made within each stamped area. The number of marks corresponds to a calibration number. The total number of follicular units to be transplanted into the recipient site can readily be calculated as the product of the recorded count and the calibration number.

[0030] , In the next step of the procedure the stamp tool 26 is replaced with a scalpel tool 27. A sleeve 32 of a tubular plastics material is placed over the scalpel shaft, to leave a length of the scalpel blade exposed. The tube prevents incision beyond a predetermined depth. The tube also ensures that at the predetermined cut depth, the end of the tube bears on the patient’s skin so that the force applied to make the incision is transmitted to the microswitch and provokes the instrument to increment the counter by one each time an incision is made. The predetermined and appropriate depth is one adjudged, or cut, by the practitioner to the patient’s average hair graft length.

[0031] , The practitioner may find it helpful to incline the scalpel or stamp with the shaft off axis. Inclining the scalpel facilitates accurate natural hair placement angle relative to the scalp. Because the handle is asymmetric to facilitate grip it is useful to be able to alter the rotary position of the tool with respect to the handle. To achieve this the chuck assembly can be pulled forward into the space 20 to disengage the splines of the chuck assembly from the magnet assembly and rotated to any angle available around the axis. When released the magnet will re-engage the splines at the nearest available angle.

Claims

An instrument for hair transplant surgery comprising an elongate handle with a front end and a rear end;a chuck assembly mounted into the front end of the handle to removably hold a tool;an electronics assembly in a chamber in the handle including a sensor mounted to sense a force applied longitudinally to the chuck and responsive to sensing the force to increment a counter and a display arranged responsive to the counter to display the integrated count;characterised in that the tool held in the instrument chuck comprises a stamp, said stamp having a shaft for engagement in the chuck, and a foot bearing a marking surface able to carry a charge of ink to mark the periphery of a predetermined area of skin.An instrument according to claim 1 wherein the chuck is retained in the handle by a magnet.An instrument according to claim 2 wherein the magnet secures the chuck in engagement with the sensor.An instrument according to claim 3 wherein the sensor is a microswitch.An instrument according to claim 4 wherein the microswitch provides a tactile feedback to indicate when the microswitch is closed in response to a force exceeding a predetermined force.An instrument according to claim 4 or claim 5 wherein the microswitch provides an audible signal to indicate when the microswitch is closed in response to a force exceeding a predetermined force.7.An instrument according to any one of the preceding claims wherein a brake acts between the chuck assembly and the handle to prevent relative rotation of the chuck assembly and the handle to facillitate tightening and loosening of jaws of the chuck.8.An instrument according to claim 7 wherein the brake comprises a rotation brake cap irrotatably secured to the magnet and a brake part of the chuck assembly which prevent relative rotation when urged into engagement by the magnet and can be selectively disengaged to facilitate relative rotation.9.An instrument according to claim 8 wherein the brake cap and the brake part are provided with cooperative interengageable parts which can be disengaged by axial displacement.10.An instrument according to claim 9 wherein the cooperative interengageable parts are any one of:radial splines,axial splines,a non-circular projection and a corresponding non-circular socket, a polygonal projection and a corresponding non-circular socket, an axially symmetric arrangement of pins cooperable with a corresponding arrangement of sockets;whereby the chuck can be selectively secured at a range of angular relationships with the handle.11.An instrument according to any one of the preceding claims wherein the chuck assembly comprises a core providing chuck jaws, said core being threadedly secured into a chuck part of the chuck assembly, whereby the core can be exchanged for a substitute core in order to provide an alternative selection of chuck jaws.12.An instrument according to any one of the preceding claims wherein the electronics assembly comprises a correction switch manually operable to subtract a count of one to correct erroneous operation by the practitioner.13.An instrument according to any one of the preceding claims wherein the stamp tool comprises a foot and a shaft all formed from an integral resilient wire.14.An instrument according to claim 13 wherein the shape of the foot is one of a: triangle rectangle, hexagon, curve sided rectangle.15.An instrument according to one of claims 13 or 14 wherein the stamp has a portion of the shaft flattened.16.A method of measuring the area of recipient site of a patient during hair transplant surgery comprising the steps of:providing an instrument having a handle supporting a chuck in which a stamp is engaged;charging the stamp with a charge of ink;applying the stamp to a portion of the area of recipient site of a patient in order to markthe skin with the ink such that a sensor of an electronics display in the instrument is actuated to cause a counter circuit to increment a count of one and display the integrated count visibly on a screen;a subsequent step of applying the stamp to the unmarked recipient site of the patient with sufficient force to cause the counter to increment a count of one;repeating the subsequent step until the whole of the bald area to be subject to hair transplant is marked with the stamp.17.A method according to claim 16 comprising the step of calibrating the stamp to determine the number of incisions corresponding to the area marked out by the stamp.18.A method according to claim 17 wherein the step of calibrating the stamp comprises, inking the stamp, applying the stamp to a substrate to mark out the substrate, applying an incision making tool or a writing instrument to mark the substrate, within the area inked out by the stamp, at regularly spaced locations until the area is filled, counting the number of marks.

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