WO2001028447A1

WO2001028447A1 - Method and system for laser surgery

Info

Publication number: WO2001028447A1
Application number: PCT/US2000/028978
Authority: WO
Inventors: Wolfgang Illich; Albert J. Nemeth
Original assignee: Wolfgang Illich; Nemeth Albert J
Priority date: 1999-10-19
Filing date: 2000-10-19
Publication date: 2001-04-26
Also published as: WO2001028447A9; AU1654201A

Abstract

A surgical laser handpiece includes a tubular aluminum handle, which connects to a standard optical articulating arm to receive an output from an Er:YAG or a similar surgical laser. The output or laser energy can be transmitted through an optical objective, and can then be focused on a surgical contact tip made of sapphire or other laser transmissible materials. The incoming laser beam can be guided by the surgical contact tip to the tissue where it ablates the tissue. The surgical contact tip can also be fabricated to any desired size and shape, depending upon the needs of the particular application.

Description

METHOD AND SYSTEM FOR LASER SURGERY

FIELD OF THE INVENTION The invention relates generally to surgical laser handpieces, and more particularly, to laser handpieces for precision laser surgery such as hair transplantation.

BACKGROUND OF THE INVENTION Lasers of various types have been employed in surgical applications for some time. Laser energy may be used either for cutting or ablating tissue. In most conventional applications, laser energy is delivered in the form of a free beam that is visually aimed at the desired target tissue. Among the disadvantages of free beam laser delivery are scattering of the beam in the periphery of the selected target site and loss of tactile feedback to the surgeon, with resulting uncertainty as to the depth of the cut achieved.

As an alternative to free beam laser delivery, others have used a contact laser tip that is heated by the laser energy in order to enhance the cutting effect. In a contact application, the laser energy is optically delivered to a suitable substance that has been machined to serve as a cutting tip. The contact material must be capable of optically transmitting the laser energy and of withstanding the thermal impact of this transmission. Depending upon the application and type of laser employed, various substances such as specialized optical glass, quartz, ruby, diamond, and sapphire have been used to form contact laser tips. In a specific surgical application where the object of employing a laser is to make an incision in a tissue, such as skin, it is important that the final energy delivery be precise, with minimal unwanted effect on adjacent tissue. Moreover, it is important that the depth of the laser cut be predictable and controllable by the surgeon. Some laser systems, such as many carbon dioxide lasers, tend to produce thermal iterations at some depth into the tissue from their surface incisions. The extent of an underlying thermal injury resulting from the thermal iterations may not be apparent at the time of surgery, and can affect wound healing in some situations.

Conventional carbon dioxide lasers are typically used in surgical techniques such as hair transplantation. Hair transplantation operative procedures are conventionally performed by making small slit-like incisions, which then receive implants of 1-4 hair follicles which are harvested from a non-bald donor site on the same patient. These procedures have a better cosmetic result than "corn rows" which often resulted from the larger, plug implants that were previously used. A single operative procedure may involve more than 1,500 individual incisions and implants. When the incisions are made using mechanical methods, bleeding from the incision sites can slow the procedure. Bleeding can also complicate the post-operative course and results. In addition, compression of the delicate donor follicles by the edges of the mechanical incision can compromise the vascular supply to the graft, and result in loss of the donor hair follicles. The aforementioned slit technique had a tendency to result in some pitting or tufting of the skin surface, according to Hitzig, et al. (Dermatological Surgery, 22(9)788-792, 1996), who advocated use of a small linear punch that removed a small central area of skin, leaving a slot instead of a linear slit. According to this research, this small slot was sufficient to accommodate the donor follicles without compression from the skin edges.

Ho, et al. (Dermatological Surgery, 21(12)1056-1059, 1995) proposed the use of a carbon dioxide laser for these procedures with a special handpiece for the laser that produced a 2.0 mm slit. The proponents of the carbon dioxide laser have reported better hemostasis and minimal tissue necrosis as compared with the mechanical incision procedure. However, as previously stated, carbon dioxide lasers are prone to producing significant thermal injuries to tissue adjacent or deep to the intended surgical incision.

In U.S. Patent No. 5,071,222, Laakmann et al. describes the use of a sapphire tip with an Nd:YAG laser system for contact laser surgery. The sapphire tips are used to convert the laser energy into heat at the interface between the tip and biological tissue. However, Laakmann notes several deficiencies with the use of sapphire tips in these applications. For example, sapphire tips are fragile, and thus there is a tendency for them to break when they are heated during use.

Daikuzono, in U.S. Patent Nos. 4,736,743, 4,592,353, and 4,693,244 discloses a medical laser probe for contact laser surgery which utilizes laser transmissible materials such as sapphire, quartz, or diamond. The Daikuzono patents employ contact tips which have been roughened and then coated with an infrared-absorbing material.

Long, et al, U.S. Patent No. 5,154,708, present a contact laser scalpel, which employs a coaxial optical fiber to heat a tapered ceramic tip. Schuman in U.S. Patent 5,607,420 describes a hand instrument containing a bendable coaxial optical fiber with parallel channels for suction and irrigation, as well as a disposable contact laser tip that is heated in order to remove tissue.

The prior art contact tips for use with lasers are fabricated to produce either round or slit-like incisions. As stated above, it would be preferable to make a slot-like incision with a surgical laser handpiece for removal of a small central piece of skin for hair transplantation surgery, so that the wedges of the small wound do not compress the implanted hair follicles during healing.

As noted above, carbon dioxide lasers have been used with surgical laser handpieces and have yielded undesirable thermal injuries. Other lasers, such as Nd:YAG lasers, have been used to heat contact tips in surgical handpieces in order to ablate biological tissue. However, these heated contact tips require special materials because some common materials that conduct laser energy are fragile and tend to break when they are heated. The prior art has not contemplated employing lasers operating at wavelengths different than carbon dioxide and Nd:YAG wavelengths for ablating tissue without substantially heating contact tips.

Lasers operating at wavelengths different than carbon dioxide and Nd:YAG wavelengths include Erbium:YAG lasers. The use of Erbium:YAG lasers heretofore has been limited to specific applications. For example, Erbium:YAG lasers have been used in dermatological applications, such as skin resurfacing and the removal of acne scars. These lasers have also been used for drilling holes in dentistry applications, in free beam form for neurosurgery, and for cataract surgery. However, Erbiunr.YAG lasers have not been used for precision contact surgery applications, such as hair transplantation.

Accordingly, there is a need in the art for a handpiece for surgery with the Er:YAG laser (or other similar lasers, such as a Ho:YAG laser) that contain laser contact tips that are not substantially heated by the laser light and thus produce less thermal injury. In other words, there is a need in the art for laser contact tips that are designed to pass laser energy so that such energy ablates tissue without heating the contact tip to a temperature that can degrade the performance of the tip. There is also a need in the art for contact materials of laser handpieces comprising substances that may readily be machined or fabricated to a shape and size appropriate for predefined clinical uses. And lastly, a need exists in the art for a surgical method in which a surgeon can employ a contact laser handpiece to perform precision surgical procedures such as hair transplantation surgery.

SUMMARY OF THE INVENTION

The present invention generally relates to contact surgical handpieces that contain contact tips that are not substantially heated and are designed to deliver laser energy to specific sites for delicate surgical procedures. A contact surgical handpiece for Erbium:YAG or similar lasers described herein can provide an ergonomical tool for precise use of laser systems in delicate surgical procedures where it is necessary to minimize inadvertent thermal injury to tissues adjacent to the surgical site. Furthermore, the present invention can produce surgical incisions using laser energy in a variety of shapes or sizes, depending upon the configuration of the contact tip selected. The contact laser tips of the present invention can offer improved optical and mechanical functions over the prior art.

In addition to the inventive apparatus above, the present invention can also provide improved methods of surgery. In one exemplary embodiment, the present invention comprises an inventive procedure for hair transplantation surgery. With surgical techniques using the inventive apparatus, hair transplantation can be significantly improved over previously known systems and practices. The present invention can also provide a system to deliver energy from an Erbium:YAG or a similar laser system to a delicate surgical site using a contact handpiece that focuses the laser energy to tissue without substantial heating of the contact tip. The present invention can also provide a disposable laser contact tip for use with an Erbium:YAG or a similar laser to provide technically consistent operative results as well as a safe, sterile, and contamination-free delivery of laser energy to a surgical patient.

In one exemplary embodiment, the contact laser handpiece can comprise a tubular aluminum handle, which connects to a standard optical articulating arm to receive an output from an Erbium: YAG surgical laser. The output of laser energy can be transmitted through an optical objective, and can then be focused on a contact tip made of sapphire or other material highly transmissive within the Erbium wavelength region, which is approximately 2940 nm. The incoming laser beam is guided by the contact tip to the tissue in surgery where the laser ablates the tissue without substantially heating the contact tip. The contact tip can be fabricated to any desired size and shape, depending upon the needs of the particular application.

When the present invention is employed in an exemplary use of hair transplantation surgery, it can create a series of small slot-like incisions. The present invention can produce these slot-like incisions by ablating the minute strip of tissue within the slot. Such incisions can be beneficial for hair transplantation surgery because the wedges of the small wound do not compress the implanted hair follicles during healing. The removal of the tissue within the incision can reduce the possibility of damage to delicate follicle micrografts adjacent to the recipient wound edges.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a surgical laser handpiece used in accordance with an exemplary embodiment of the present invention.

FIG 2 illustrates an exemplary handpiece according to the present invention connected to an optical articulating arm of a laser system. FIG. 3 is a cross-sectional view of a contact tip assembly constructed in accordance with an exemplary embodiment of the present invention.

FIG. 4 illustrates a surgical laser handpiece with a contact tip assembly constructed in accordance with an exemplary embodiment of the present invention. FIG. 5 provides a close up view of the surgical laser handpiece and the contact tip assembly constructed in accordance with an exemplary embodiment of the present invention.

FIG. 6 is a side view of the distal tip of a surgical laser handpiece and a contact tip assembly constructed in accordance with an exemplary embodiment of the present invention.

FIG. 7 illustrates exemplary incisions formed by the surgical laser handpiece of the present invention.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

In an exemplary embodiment of the present invention as in FIG. 1, a handpiece 100 comprises a tapering cylinder 7, that is hollow throughout its longitudinal axis, with a defined proximal end and a defined distal end. The body of the handpiece 100 may taper at intervals along its length between the proximal and distal ends. The handpiece 100 can be made from any one of aluminum, brass, and other like metals. However the present invention is not limited to these materials. Other materials include, but are not limited to, ceramics, plastics, and other like materials.

The proximal end of the handpiece 100 contains external threads 5 to allow it to be mounted within a female portion of an articulating optical arm 50 that comprises a laser system or optical waveguide, as illustrated in FIG 2. In one exemplary embodiment, the laser system can operate in a continuous wave mode at an energy level sufficient to remove biological tissue by vaporization. The laser system is preferably an Erbium-doped Yttrium-Aluminum-Garnet laser (Erbium:YAG), however it will be understood that other similar laser systems could also be used, such as a Holmium-doped Yttrium Aluminum-Garnet laser (Ho:YAG), an Erbium-doped Yttrium-Aluminum-Flouride laser (EπYAF), and a Holmium-doped Yttrium- Aluminum-Flouride (Ho:YAF) laser. Other types of lasers and lasers combined with optical filters that can alter the wavelength, frequency, or other optical characteristics of laser energy are not beyond the scope of the present invention. Adjacent to the threads 5 and within the central lumen of the handpiece

100 is one or more optical objective lenses 10 which serve to direct the incoming laser energy beam (not shown) down the central axis A-A of the handpiece 100 towards a tip 45. The objective lens 10 is preferably comprised of sapphire. However, other materials capable of propagating incident laser energy may also be used, such as natural or artificial crystals, diamond, quartz, and silica. The lens 10 may include optical coatings that are qualitatively matched to the operating wavelength of the laser energy beam. For example, for EπYAG laser energy, the coatings can be qualitatively matched for the operating wavelength of this type of laser energy propagating in the 2940 nm wavelength region. At the distal end of the handpiece 100, one or more spring- loaded bearings 20 protrude into the central lumen. The spring-loaded bearings 20 serve to retain a connector 40, which in turns holds the contact tip 45.

As illustrated in FIG. 3, the connector 40 can comprise a sleeve 25 and a flange 35 that extends beyond the end of the handpiece 100. The connector 40 can be fabricated from brass or aluminum. However, the present invention is not limited to these materials. The sleeve 25 of the connector 40 is received by the distal end of the handpiece 100 and is retained by the spring-loaded bearing(s) 20 on a concentric recess 30 in the outer surface of the sleeve 25. The connector 40, like the handpiece 100 has a hollow central portion to allow passage of the laser beam. Within the hollowed central portion of the connector 40, a surgical contact tip 45 is secured.

The contact tip 45 in one exemplary embodiment is fabricated from sapphire. However, the contact tip 45 is not limited to this material. Other materials include, but are not limited to, diamond, quartz, silica or other natural or artificial crystals, or other heat resistant materials capable of propagating laser light into biological tissue. The contact tip 45 can be machined so that it can be retained within the connector 40 by a friction fit. Unlike conventional handpieces, in which the contact tip is heated to achieve coagulation and cutting, the contact tip 45 in the present invention is not heated by the Erbium laser. Thus, the contact tip 45 functions solely as a beam-shaper for the laser light, i.e., to direct and shape the laser beam to the desired position and geometry for the particular surgical application. The portion of the contact tip 45 that is within the connector 40 central portion fills the interior of the connector 40. The end of the contact tip 45 that is outside the central portion of the connector 40 is machined to a desired shape and length. In an exemplary embodiment, the contact tip 45 can be between 0.5 and 5.0 cm in length. The tip can be finished to taper or bevel into either a rectangular or ovoid shape, with a cross-sectional tip dimension of approximately 0.1 - 5.0 mm in height to 0.1 - 5.0 mm in width. The end portion of the tip 45 in one exemplary embodiment is flat. However, the present invention is not limited to these shapes or sizes.

Another exemplary embodiment of the present invention is further illustrated in FIGS. 4-6. A contour of the outer surface of the handpiece 100 can comprise a series of finger rests 15 that provide the instrument a more ergonomic grip (FIGS. 4-6). The finger rests 15 are positioned to allow either right- or left-handed operation of the instrument. As illustrated in FIG. 5, near the distal end of the handpiece 100, a threaded bore may be provided for a set screw 38, as an alternative to the spring-loaded bearing(s) 20 to retain the connector assembly 40 within the handpiece 100. When the connector 40 is fully inserted, the flange 35 abuts the distal end of the handpiece 100. The contact tip 45 extends beyond the flange 35, and has the same longitudinal axis as the shaft of the handpiece 100.

EXEMPLARY OPERATION OF THE PRESENT INVENTION

In one exemplary embodiment, the surgical handpiece of the present invention is designed for use with an Erbium:YAG or another similar laser system.

Erbium lasers, tend to produce much less thermal injury in the tissue adjacent to the surgical site. The Erbium: YAG laser operates at a wavelength of 2.94 microns (2940 nm) and is capable of cutting and ablating both hard and soft tissue. The precise delivery effect of the Erbium: YAG lasers make these instruments particularly suitable for delicate soft tissue surgery at lower pulse energies. The Erbium:YAG laser can be used with higher pulse energies when the cutting or ablation of denser tissue or bone is desired. As noted above, Erbium:YAG lasers produce less inadvertent thermal injury in adjacent tissues when these lasers are used in surgery. In the exemplary embodiment, the laser operates with an average power of 10W max, and a pulse energy of 1 Joule max.

As illustrated in FIG. 2, the handpiece 100 connects with the laser through a conventional articulating optical arm 50. A contact tip 45, preferably made of sapphire or other similar material in one exemplary embodiment, is inserted and secured in the distal tip of the handpiece 100. When a laser of the articulating optical arm 50 is activated, the laser beam is transmitted through the optical objective lens 10 in the handpiece, and is focused on the internal surface of the contact tip 45. In an exemplary embodiment, the diameter of the laser light incident on the optical objective lens 10 is 8 mm max, with a divergence of 4.5 mrad. The laser radiation is guided through the contact tip 45 to allow either the desired cutting and/or ablating effect on biological tissue without substantial heating of the tip 45. In other words, in one preferred and exemplary embodiment of the present invention, the tip 45 is designed to focus the laser radiation to a specific shape or geometry without heating the tip 45 to a temperature that could damage biological tissue. Stated differently, while the tip 45 can be incidentally heated because of the passage of the laser radiation, the laser radiation is not intended to heat the contact tip 45 to a temperature that can ablate or damage biological tissue. Thus, the laser radiation of the present invention can provide more of the ablating function than the tip 45. The geometry of the laser light propagated from the contact tip 45 is determined by the particular shape of the tip 45. In use, the surgeon manually controls the handpiece 100 with tactile sensory feedback provided by the contact tip 45.

An exemplary surgical application for the present invention is hair transplantation surgery. One currently preferred and exemplary technique for hair transplantation involves the implant of micrografts of clusters of 1-4 hair follicles, which are harvested from a strip of hair-bearing scalp. These micrografts have traditionally been inserted in small slit-like incisions. The micrografts are extremely fragile, and compression from the edges of the incision has been blamed for a significant percentage of graft failures following surgery. Unlike carbon dioxide lasers (free beam) and Nd:YAG lasers (with heated contact tips), an Erbium:YAG laser employed by the present invention can reduce or substantially eliminate thermal damage to adjacent tissue, especially when the laser is combined with the contact tip 45 of the present invention that focuses the laser light without substantially heating the tip 45. This reduction in thermal injury is obtained, in part, because the Erbium laser is a pulse laser (250 microseconds pulse length) and thus does not generate excessive heat in the contact tip 45 as do Nd:YAG lasers and carbon dioxide lasers. Thus, the Erbium laser does not heat the contact tip 45 to a temperature for ablating biological tissue. As a result, less thermal damage is caused to the skin.

The handpiece of the present invention can be used with an Erbium:YAG laser to remove small slots in the skin using suitably shaped sapphire tips. With the Erbium: YAG laser thermal injury that could compromise the vascular supply to the implant is avoided. As illustrated in FIG. 7, the resulting incisions 700 in the head 705 of a patient produced with this exemplary embodiment are ideal for placement of the hair micrografts. To produce the incisions 700, a sufficient amount of tissue, such as an amount taken in the shape of a small slot, is removed to prevent compression of the follicles.

Moreover, the combination of an Erbium: YAG laser and the handpiece 100 allow incisions to be made quickly, with excellent hemostasis. This efficiency is particularly desirable where a thousand or more individual grafts may be placed in a single surgical procedure. It should be understood that the foregoing relates only to illustrative embodiments of the present invention, and that numerous changes may be made therein without departing from the spirit and scope of the invention as defined by the following claims.

Claims

CLAIMSWhat is claimed is:

1. A system for performing laser surgery, comprising: an Erbium:YAG laser light energy source; and a surgical handpiece comprising: a hollow cylinder having a proximal and distal end; an optical objective disposed within said hollow cylinder for focusing the Erbium:YAG laser light energy towards said distal end; a contact tip disposed adjacent to said distal end, said contact tip being adapted to propagate the Erbium:YAG laser light energy toward a desired location on the skin, whereby an incision is formed in said desired location.

2. A method for preparing skin for hair transplantation, comprising the steps of: generating laser light with an Erbium-doped Yttrium-Aluminum- Garnet laser; propagating the laser light through a contact tip; forming an incision in the skin with the laser light; and removing a piece of the skin.

3. The method of Claim 2, wherein the geometry of the laser light propagating through the contact tip is determined by the shape of the contact tip.

4. The method of Claim 2, further comprising the step of placing hair micrografts into the incision.

5. The method of Claim 4, whereby compression of hair follicles of the hair micrografts by the tissue surrounding the incision and thermal injury that could compromise the vascular supply to the hair micrografts are substantially reduced

6. The method of claim 2, wherein the contact tip is composed of one of sapphire, quartz, diamond, and silica.

7. A method for ablating tissue, comprising the steps of: generating laser light with an Erbium-doped Yttrium-Aluminum- Garnet laser; propagating the laser light through a contact tip without substantially heating the contact tip to a temperature that ablates the tissue; forming an incision in the tissue with the laser light; and removing a piece of the tissue.

8. A surgical handpiece for use in preparing skin for hair transplantation, comprising: a hollow cylinder having a proximal and distal end; an optical objective disposed within said hollow cylinder for focusing Erbium: YAG laser light energy towards said distal end; a contact tip disposed adjacent to said distal end, said contact tip being adapted to propagate the Erbium:YAG laser light energy toward a desired location on the skin, whereby an incision is formed in said desired location.

9. The surgical handpiece of claim 7, wherein the contact tip is composed of one of sapphire, quartz, diamond, and silica.

10. The surgical handpiece of claim 7, wherein said contact tip has a length between 0.5 and 5.0 cm.