Patent Publication Number: US-2018042772-A1

Title: Variable-gauge microsurgical instruments for use in ophthalmic or vitreoretinal surgery

Description:
TECHNICAL FIELD 
     The present disclosure relates generally to ocular surgery devices and, more particularly, to variable-gauge microsurgical instruments for use in ophthalmic or vitreoretinal surgery. 
     BACKGROUND 
     A common treatment often utilized in ophthalmic and vitreoretinal surgery is that of directing laser energy to a surgical site, the targeted surgical site typically being proximate a patient&#39;s retina and the surrounding vitreous. Such a surgery is called an endo-ocular photocoagulation procedure, and may be indicated for reattachment of a detached retina, for cauterization of a ruptured blood vessel, for repair of a surgical wound, for removal of defective tissue or vitreous material, and the like. 
     In order to conduct the endo-ocular photocoagulation procedure, or other type of ophthalmic or vitreoretinal surgery, the surgeon must utilize a microsurgical laser probe to deliver the laser energy to the surgical site within an eye. The microsurgical laser probe typically comprises a handle with a small cylindrical tip projecting from the distal end of the handle. An optical fiber element is connected at the proximal end to a laser source, and the fiber is carried through the microsurgical laser probe and into the cylindrical sleeve. The optical fiber element is positioned adjacent the distal end of the cylindrical tip in order to effectively deliver laser energy to the intended surgical site. 
     In a typical ophthalmic or vitreoretinal surgery, as shown in  FIG. 1 , a probe tip  5  of a surgical instrument  1  is inserted into an eye  2  via a trocar cannula  4  positioned in an entry point  3  made in the eye  2  (or in some cases via direct contact with the entry point  3 ). After the probe tip  5  is inserted into the eye  2 , the surgeon manipulates a hand piece  6  of the surgical instrument  1  to pivot and/or rotate the probe tip  5  at its junction with the trocar cannula  4  and thus move the probe tip  5  to the desired location within the eye  2 . In some cases, the probe tip  5  may be inserted into the eye  2  at variable depths, without any rotation. As an example, during a vitrectomy surgery, the surgeon manipulates the hand piece  6  to “chase” the vitreous humor with the probe tip  5 . In order to consistently and effectively maneuver the probe tip  5  of the surgical instrument  1  within the eye  2 , the gauge size of the probe tip  5  preferably corresponds with the inner diameter of the trocar cannula  4  (or direct entry point  3 ). 
     Ophthalmic and vitreoretinal surgery may be performed using a variety of sizes and types of probe tips. Currently, microsurgical laser probe tips are available in several predominant sizes, such as: 20 gauge (0.0360 inches), 23 gauge (0.0255 inches), 25 gauge (0.0205 inches), and 27 gauge (0.0165 inches). In some cases, even smaller gauge sizes may be used. The selection of which size and/or type of microsurgical laser probe tip to use in a surgery may be based on the nature of the procedure (e.g., the size of the trocar cannula most appropriate for a particular procedure) as well as the personal preference of the surgeon. For example, a surgeon may have been trained in and become accustomed to performing a particular procedure using a 23 gauge probe tip. Since the maneuverability and flexibility of a probe tip is affected by the gauge of the probe tip, the surgeon may experience difficulty in effectively performing the procedure with a differently sized probe tip than he or she is used to. Similarly, one type of ophthalmic or vitreoretinal surgery may favor one size of probe tip while another type may favor another size of probe tip. 
     In a conventional arrangement, a hospital inventory would have to maintain each type of microsurgical laser instrument with each size of probe tip. This may impose substantial burden in terms of cost, space, and inventorying effort. Thus, there is a need to provide microsurgical instruments with probe tips that can flexibly accommodate the varying preferences of multiple surgeons as well as the requirements of different types of ophthalmic or vitreoretinal surgeries. 
     SUMMARY 
     A variable gauge microsurgical probe use in ophthalmic or vitreoretinal surgery is provided herein. In one aspect, a surgical probe may include a hand piece and a probe tip attached to the hand piece. A functioning member, such as an optic fiber, may be at least partially disposed within the probe tip. The surgical probe may further include a sleeve configured for a substantially flush-fit engagement with a first size of a surgical point of entry, such as a cannula. The sleeve may be insertable over at least a portion of the probe tip. Further, the sleeve may have an outer diameter that is larger than an outer diameter of the probe tip. 
     Also provided herein is a method of performing ophthalmic or vitreoretinal surgery using a surgical probe having a hand piece and a probe tip attached to the hand piece and carrying a functioning member, such as an optic fiber providing a laser or other type of light energy. The method may include inserting a sleeve over at least a portion of the probe tip. The sleeve may have an outer diameter that is larger than an outer diameter of the probe tip. The method may further include inserting the probe tip through a surgical point of entry, such as a cannula, until the sleeve realizes a substantially flush-fit engagement with the surgical point of entry. The surgical probe may be manipulated with the sleeve in flush-fit engagement with the surgical point of entry to effectuate the ophthalmic or vitreoretinal surgery. 
     In further aspects of the above surgical probe or method, the sleeve may be removably coupled to the probe tip of the hand piece. The sleeve may be removably coupled to the probe tip or the hand piece via a threading provided on the sleeve, a magnet provided on the sleeve or the hand piece, or a friction fit between the sleeve and the probe tip. 
     The sleeve may have a gauge size between 19 gauge and 34 gauge. In some aspects, the sleeve may have a gauge size smaller than 34 gauge. 
     The sleeve may be configured to be deployable and retractable with respect to the hand piece such that, in a first position, the sleeve is retracted at least partially within the hand piece and, in a second position, the sleeve is deployed from the hand piece and over at least a portion of the probe tip. The sleeve may be deployed and retracted with respect to the hand piece via a manipulation mechanism. The manipulation mechanism may include a sliding member associated with the hand piece and operatively coupled with the sleeve, threading associated with the sleeve, or a gear rack associated with the sleeve and a rotating element engaged with the gear rack. 
     In some aspects, the sleeve may comprise an outer sub-sleeve and an inner sub-sleeve movably positioned within the outer sub-sleeve. The inner sub-sleeve may cover at least a portion of the probe tip. The inner sub-sleeve may be configured for a substantially flush-fit engagement with a first size of a surgical point of entry and the outer sub-sleeve may be configured for a substantially flush fit engagement with a second size of a surgical point of entry. The sleeve comprising the inner and outer sub-sleeves may be configured such that at least one of the sub-sleeves may be deployed and retracted with respect to the hand piece. Thus, in a first position, at least one of the sub-sleeves may be retracted at least partially within the hand piece and, in a second position, the at least one of the sub-sleeves may be deployed a least partially from the hand piece and over at least a portion of the probe tip. Further, the inner sub-sleeve may be deployable and retractable with respect to the outer sub-sleeve. 
     The inner sub-sleeve and the outer sub-sleeve may each have a gauge size between 19 gauge and 34 gauge, wherein the gauge size of the outer sub-sleeve is larger than the gauge size of the inner sub-sleeve. In some aspects, the inner sub-sleeve and/or the outer sub-sleeve may each have a gauge size smaller than 34 gauge. 
     Various additional features and advantages will become more apparent to those of ordinary skill in the art upon review of the following detailed description of the illustrative embodiments taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following detailed description is better understood when read in conjunction with the appended drawings. For the purposes of illustration, examples are shown in the drawings; however, the subject matter is not limited to the specific elements and instrumentalities disclosed. In the drawings: 
         FIG. 1  illustrates a prior art surgical instrument being used to perform an ophthalmic or vitreoretinal surgery; 
         FIGS. 2A, 2B, and 2C  illustrate a partial cut-away view of a surgical instrument according to an embodiment of the present disclosure; 
         FIGS. 3A, 3B, and 3C  illustrate a partial cut-away view of a surgical instrument according to an embodiment of the present disclosure; 
         FIGS. 4A, 4B, and 4C  illustrate a partial cut-away view of a surgical instrument according to an embodiment of the present disclosure; and 
         FIGS. 5A, 5B, 5C, and 5D  illustrate a partial cut-away view of a surgical instrument according to an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     In a form of the present disclosure chosen for purposes of illustration, an exemplary embodiment  200  of which is illustrated in  FIGS. 2A, 2B, and 2C , a variable-gauge microsurgical instrument for use in ophthalmic or vitreoretinal surgery is shown. A hand-held surgical instrument  10  may connect one or more of a light and a laser source S through one or more optical fibers  20  via one or more connectors  28  disposed from a proximal end  40  of the surgical instrument  10 , with the distal, delivery end  50  of the surgical instrument for use inside the eye when held by a surgeon at the hand piece  105 . The laser energy may, for example, be used for ophthalmic and vitreoretinal procedures involving the retina, surrounding tissue, and vitreous. Illumination energy may be supplied to illuminate the targeted surgical site. Exemplary of such a combined laser and illumination energy delivery device is Applicant&#39;s U.S. patent application Ser. No. 11/934,761, filed on Nov. 3, 2007, now U.S. Pat. No. 8,647,333, the disclosure of which is hereby incorporated by reference. In other embodiments, one or more dedicated illumination optical fibers may run parallel to one or more dedicated laser energy optical fibers and connect to respective illumination and laser sources. 
     The surgical instrument  10  is configured with a probe tip  30  fixed to the hand piece  105  and carrying a functioning member, such as the optical fiber  20 . The probe tip  30  may be formed as a tube, for example, with the optical fiber  20  or other type of functioning member being disposed therein. The optical fiber  20  may be co-terminus with the probe tip  30 . The probe tip  30  may be sized according to one of an industry standard size (e.g., 19, 20, 23, 25, or 27 gauge), but is not so limited. It is further contemplated that the probe tip  30 , as well as the below-described sleeve, may be sized according to future industry standard sizes as they might evolve, for example, due to a trend of miniaturization. Accordingly, the probe tip  30  or sleeve may be sized at  31 ,  34 , or smaller gauge. The probe tip  30  may be formed with a curvature towards the distal end  50 , while in other aspects, the probe tip  30  may be generally straight. Further, according to the gauge size of the probe tip  30 , the probe tip  30  may exhibit varying degrees of flexibility. 
     While the surgical instrument  10  is generally described as encompassing a surgical instrument with a probe tip configured with an optic fiber to deliver laser or other light energy, this is just one illustrative embodiment and the disclosure is not so limited. For example, the probe tip  30  may be configured to provide one or more types of functioning members for effectuating an ophthalmic or vitreoretinal surgery, in addition or in alternative to the optic fiber  20 . Examples of such a functioning member may include a vitrectomy probe, a diathermy probe, or an instrument, such as scissors or a pick. 
     It will be understood that references to the gauge or size of the probe tip  30  or the below-described sleeve generally describe the outer diameter of such component, unless otherwise indicated explicitly or by context. Further, however, references to the gauge or size of a cannula or other surgical point of entry through which the probe tip  30  and/or sleeve are inserted generally describe the inner diameter of such component, again unless otherwise indicated explicitly or by context. More particularly, the gauge or size of a cannula, etc. is generally described according to the gauge or size of the probe tip  30 , sleeve, or other insertable component that the cannula, etc. is designed to securely but movably accommodate. Thus, for example, a 25 gauge probe tip  30  may be paired with a 25 gauge cannula such that the inner diameter of the 25 gauge cannula is about the same or slightly larger than the outer diameter of the 25 gauge probe tip  30 , thus allowing the 25 gauge probe tip  30  to be freely inserted and retracted through the cannula with minimal “wiggle” or “play.” 
     As shown in  FIGS. 2B and 2C , the surgical instrument  10  may include a sleeve  60  that is positioned over the probe tip  30  of the surgical instrument  10  to increase the gauge of the probe tip  30 , such as to accommodate a surgeon&#39;s personal gauge preference or to comply with the requirements of a particular type of surgery (e.g., to match the gauge size of a cannula or other surgical point of entry). In the embodiment shown in  FIGS. 2B and 2C , the sleeve  60  is formed as a separate component from the probe tip  30  and the hand piece  105  and may be inserted over and/or removed from the probe tip  30  as needed. Accordingly, the sleeve  60  may be attached to the probe tip  30  and/or the hand piece  105  using various means amenable to readily attaching and detaching the sleeve  60  to the probe tip  30  and/or the hand piece  105 . For example, the sleeve  60  and the hand piece  105  may each be configured with cooperatively-engaging threading to removably attach the sleeve  60  to the hand piece  105 . As another example, at least one of the sleeve  60  or hand piece  105  may be configured with a magnet to removably attach the sleeve  60  to the hand piece  105 . As yet another example, the sleeve  60  and the probe tip  30  may each be sized so that the sleeve  60  is sufficiently secured over the probe tip  30  via a friction fit therebetween. 
     In other aspects, the sleeve  60  may be coupled with the probe tip  30  and/or hand piece  105  in a more permanent manner. For instance, the sleeve  60  may be attached to the probe tip  30  and/or hand piece  105  using an adhesive. 
     The sleeve  60  may be sized to be securely, but movably, inserted over the probe tip  30 . To this end, the inner diameter  62  of the sleeve  60  may be sized to be approximately the same as or slightly larger than the outer diameter  32  of the probe tip  30 . The outer diameter  32  of the probe tip  30  may be sized according to one of the industry standard (e.g., 19, 20, 23, 25, or 27 gauge) or smaller (e.g., 31, 34 or smaller gauge) gauge sizes so that the surgical instrument  10  may be used in a surgical procedure without the sleeve  60  if the probe tip  30  is of an appropriate and/or desirable size. The outer diameter  64  of the sleeve  60  may also be sized in one of the industry standard (e.g., 19, 20, 23, 25, or 27 gauge) or smaller (e.g., 31, 34 or smaller gauge) gauge sizes that is larger than the gauge size of the probe tip  30 . For example, the outer diameter  32  of the probe tip  30  may be sized in 25 gauge while the outer diameter  64  of the sleeve  60  may be sized in 23 gauge. Thus, by adding or removing the 23 gauge sleeve  60  with the 25 gauge probe tip  30 , as appropriate, such an exemplary surgical instrument may be used by both surgeons that prefer a 25 gauge tip and those that prefer a 23 gauge tip. 
     The sleeve  60  may be configured with a longitudinal length  66  that is substantially equal to a longitudinal length  36  of the probe tip  30 . Thus, the sleeve  60  is substantially coterminous with the probe tip  30  at the distal end  50  while the sleeve  60  is substantially flush and/or secured with the hand piece  105  at its other end. In another aspect, the longitudinal length  66  of the sleeve  60  may be less than the longitudinal length  36  of the probe tip  30 . In such an aspect, the sleeve  60  may be substantially flush and/or secured with the hand piece  105  but not coterminous with the probe tip  30  at the distal end  50 . The sleeve  60  being substantially flush and/or secured with the hand piece  105  may provide the benefit of structural support to the probe tip  30  and sleeve  60  so that the surgical instrument  10  may be reliably manipulated by the surgeon. If the sleeve  60  is not substantially flush and/or secured with the hand piece  105 , undesirable bending might occur in the more flexible probe tip  30  near its junction with the hand piece  105  when the hand piece  105  is manipulated. 
     It will be appreciated that the surgical instrument  10  may be used with one or more of a plurality of sleeves  60 , either with one sleeve  60  being inserted over the probe tip  30  at any given time or with multiple sleeves  60  of increasing size being progressively inserted over the probe tip  30  and the preceding sleeve(s)  60 . In an aspect in which only one sleeve  60  of the plurality of sleeves  60  is inserted over the probe tip  30  at any given time, each sleeve  60  may be configured with the same inner diameter  62  for secure placement over the probe tip  30  but with different (e.g. progressively larger) outer diameters  64 . In an aspect in which multiple sleeves  60  of the plurality of sleeves  60  are progressively inserted over the probe tip  30  and the preceding sleeve(s)  60 , a first sleeve  60  may be configured to securely fit over the probe tip  30  (e.g., the inner diameter  62  of the first sleeve  60  may be the same as or slightly larger than the outer diameter  32  of the probe tip  30 ), a second sleeve  60  may be configured to securely fit over the first sleeve  60  (e.g., the inner diameter  62  of the second sleeve  60  may the same as or slightly larger than the outer diameter  64  of the first sleeve  60 ), and so forth. 
       FIGS. 3A, 3B, and 3C  illustrate an alternative embodiment  300  of the surgical instrument  10 . Except as noted, construction of the alternative embodiment  300  is equivalent to the embodiment of  FIGS. 2A, 2B, and 2C . It is noted that in the embodiment  300  shown in  FIGS. 3A, 3B, and 3C , the optic fiber  20  or other functioning member has been omitted for clarity of illustration, although it is fully contemplated that the optic fiber  20  or other functioning member may be disposed within the probe tip  30 . In the alternative embodiment  300 , the sleeve  60  is configured to be deployed from within the hand piece  105  and retracted back into the hand piece  105 , as needed.  FIG. 3A  depicts the sleeve  60  fully retracted in the hand piece  105 .  FIG. 3B  depicts the sleeve  60  partially deployed over the probe tip  30 .  FIG. 3C  depicts the sleeve  60  fully deployed from the hand piece  105  and over the probe tip  30 . In some aspects, the full deployment of the sleeve  60  may bring the sleeve  60  to a point that is coterminous with the probe tip  30  at the distal end  50 . In other aspects, the full deployment of the sleeve  60  may only partially cover the probe tip  30 , i.e., the sleeve  60  is not coterminous with the probe tip  30  at the distal end  50 . This configuration in which the sleeve  60  only partially covers the probe tip  30  may be appropriate, for example, when the portion of the probe tip  30  near the distal end  50  is curved. 
       FIGS. 4A, 4B, and 4C  illustrate alternative embodiments  400 ,  410 , and  420  of the embodiment  300  shown in  FIGS. 3A, 3B, and 3C . In particular, the embodiments  400 ,  410 , and  420  illustrate various mechanisms by which the sleeve  60  may be deployed from and retracted into the hand piece  105 . Except as noted, construction of the alternative embodiments  400 ,  410 , and  420  are equivalent to the embodiment  300  of  FIGS. 3A, 3B, and 3C . It is again noted that the depiction of the optic fiber  20  or other functioning member has been omitted from the embodiments  400 ,  410 , and  420  for clarity of illustration and that it is fully contemplated that the optic fiber  20  or other functioning member may be disposed within the probe tip  30 . 
     The embodiment  400  shown in  FIG. 4A  is configured with a sliding member  402  associated with the hand piece  105  and the sleeve  60  such that the sliding member  402  may be manipulated to cause the deployment and/or retraction of the sleeve  60  with respect to the hand piece  105 . In particular, the sliding member  402  may be operatively coupled with the sleeve  60 . Thus, when the sliding member  402  is moved back and forth with respect to the hand piece  105 , the sleeve  60  is correspondingly deployed from or retracted into the hand piece  105 . 
     In the embodiment  410  shown in  FIG. 4B , a thread mechanism may be employed to effectuate the deployment or retraction of the sleeve  60 . A portion of the sleeve  60  may be configured with external threads  414 . The interior of the hand piece  105  may be configured with internal threads  412  that cooperatively engages with the external threads  414  of the sleeve  60 . As the sleeve  60  is turned relative to the hand piece  105  (or vice versa), the engagement of the external threads  414  and internal threads  412  convert this rotational movement into linear movement of the sleeve  60  along its longitudinal axis, i.e., the deployment or retraction of the sleeve  60 . The hand piece  105  may be configured with a dial  416  or other rotational element that engages with the sleeve  60  to cause rotation of the sleeve  60  when the dial  416  is rotated. At least a portion of the dial  416  or other rotational element may be positioned on the external surface of the hand piece  105  so that a user holding the hand piece  105  may rotate the dial  416  or other rotational element. Additionally or alternatively, the internal threads  412  may be rotated in-situ, thus causing the sleeve  60  to move along its longitudinal axis and deploy or retract with respect to the hand piece  105 . 
     In the embodiment  420  shown in  FIG. 4C , a gear rack mechanism may be used to deploy the sleeve  60  from the hand piece  105  onto the probe tip  30  or to retract the sleeve  60  back into the hand piece  105 . In such a configuration, the sleeve  60  may be configured with a gear rack  422  and the hand piece  105  may be configured with a gear  424 . The gear  424  may be cooperatively engaged with the gear rack  422  such that rotation of the gear  424  causes linear movement of the sleeve  60  along its longitudinal axis. That is, when the gear  424  is rotated, the sleeve  60  is deployed from or retracted into the hand piece  105 . 
       FIGS. 5A, 5B, 5C, and 5D  illustrate an embodiment  500  of the surgical instrument  10  in which the sleeve  60  is configured with two or more sub-sleeves of graduated sizes. Except as noted, construction of the alternative embodiment  500  is generally equivalent to the embodiment  200  of  FIGS. 2A, 2B, and 2C  or the embodiment  300  of  FIGS. 3A, 3B, and 3C . It is again noted that the depiction of the optic fiber  20  or other functioning member has been omitted from the embodiment  500  shown in  FIGS. 5A, 5B, 5C, and 5D  for clarity of illustration. Yet, it is fully contemplated that the probe tip  30  may include the optic fiber  20  or other functioning member disposed therein. It will be appreciated that while the sleeve  60  is depicted in the embodiment  500  as comprising two sub-sleeves, the disclosure is not so limited and it is explicitly contemplated that a sleeve may include three or more sub-sleeves assembled and used according to the concepts and principles described herein. 
     In  FIG. 5A , the embodiment  500  of the instrument is configured with the sleeve  60  having an outer sub-sleeve  60   a  and an inner sub-sleeve  60   b  movably disposed inside the outer sub-sleeve  60   a . The outer sub-sleeve  60   a  may be sized in an industry standard (e.g., 19, 20, 23, 25, or 27 gauge) or smaller (e.g., 31, 34 or smaller gauge) gauge size and the inner sub-sleeve  60   b  may be sized in a second, smaller such gauge size. For example and as depicted in  FIGS. 5A, 5B, 5C, and 5D , the outer sub-sleeve  60   a  may be sized at 23 gauge and the inner sub-sleeve  60   b  may be sized at 25 gauge. Further in this example, the probe tip  30  may be sized at 27 gauge. Accordingly, this example configuration of the embodiment  500  may be used with a 23 gauge cannula, a 25 gauge cannula, or a 27 gauge cannula, representing a significant improvement to the usefulness of the surgical instrument  10  over a conventional surgical instrument. 
     As noted above, the embodiment  500  may generally derive from the embodiment  200  shown in  FIGS. 2A, 2B, and 2C . Accordingly, the sleeve  60  with sub-sleeves  60   a ,  60   b  may be removably or non-removably attached to the probe tip  30  and/or the hand piece  105  in the manners described with respect to the embodiment  200 . 
     As also noted above, the embodiment  500  may generally derive from the embodiment  300  shown in  FIGS. 3A, 3B, and 3C  such that the sleeve  60  with sub-sleeves  60   a ,  60   b  of the embodiment  500  may be deployable from and retractable within the hand piece  105 . For example, in a first position, both the inner sub-sleeve  60   b  and the outer sub-sleeve  60   a  may be disposed within the hand piece  105  (i.e., previously retracted). This first position may be useful, for example, when the cannula used in a surgery is of a gauge size corresponding to the gauge size of the probe tip  30 . In a second position, the inner sub-sleeve  60   b  may be deployed from the hand piece  105  and over the probe tip  30  while the outer sub-sleeve  60   a  remains retracted within the hand piece  105 . This second position may be appropriate, for example, when a cannula used in a surgery corresponds to the gauge size of the inner sub-sleeve  60   b . In a third position, the outer sub-sleeve  60   a  may be deployed from the hand piece  105  and over the inner sub-sleeve  60   b . This third position may allow, for example, the surgical instrument  10  to be used with a cannula corresponding in gauge size to that of the outer sub-sleeve  60   a . In an alternative third position, the outer sub-sleeve  60   a  may be deployed from the hand piece  105  but instead of the outer sub-sleeve  60   a  moving over and covering the inner sub-sleeve  60   b , the inner sub-sleeve  60   b  moves correspondingly forward along the probe tip  30  such that the outer sub-sleeve  60   a  covers one portion of the probe tip  30  and the inner sub-sleeve  60   b  covers a second portion of the probe tip  30  nearer the distal end  50  of the probe tip  30 . 
     In another example configuration of the embodiment  500 , in a first position, both the inner sub-sleeve  60   b  and the outer sub-sleeve  60   a  may be disposed within the hand piece  105 . In a second position, the inner sub-sleeve  60   b  and the outer sub-sleeve  60   a  may both be deployed together from the hand piece  105  and over the probe tip  30 . That is, the inner sub-sleeve  60   b  remains within the outer sub-sleeve  60   a  as the sleeve  60  is deployed to the second position from the hand piece  105 . In a third position, the outer sub-sleeve  60   a  remains stationary in its position from the second position while the inner sub-sleeve  60   b  is deployed from the outer sub-sleeve  60   a  and further along the probe tip  30 . Thus, the sleeve  60  and sub-sleeves  60   a ,  60   b  may be deployed from the hand piece  105  in a telescopic manner. 
       FIG. 5B  illustrates one exemplary use of the embodiment  500  with a cannula  42  (or other surgical point of entry) sized at 27 gauge. In this exemplary use, the probe tip  30  is sized at 27 gauge, the inner sub-sleeve  60   b  is sized at 25 gauge, and the outer sub-sleeve  60   a  is sized at 23 gauge. Since the gauge size (27 gauge) of the cannula  42  matches that of the probe tip  30 , only the probe tip  30  is inserted through the cannula  42  to realize a substantially flush-fit engagement with the cannula  42 . Accordingly, the inner sub-sleeve  60   b  may remain disposed within the outer sub-sleeve  60   a . In a configuration in which the sleeve  60  is retractable within the hand piece  105 , the sleeve  60  may remain retracted within the hand piece  105  while the probe tip  30  is inserted through the cannula  42  and the surgery is performed. 
       FIG. 5C  illustrates another exemplary use of the embodiment  500  with the cannula  42 . In this exemplary use, the cannula  42  is sized at 25 gauge, the probe tip  30  is sized at 27 gauge, the inner sub-sleeve  60   b  is sized at 25 gauge, and the outer sub-sleeve  60   a  is sized at 23 gauge. Here, the gauge size (25 gauge) of the inner sub-sleeve  60   b  corresponds to that of the cannula  42 . Therefore, the inner sub-sleeve  60   b  may be deployed from the outer sub-sleeve  60   a  and inserted through the cannula  42  to effectuate the surgery. Depending on the particular configuration of the embodiment  500 , the outer sub-sleeve  60   a  may remain retracted within the hand piece  105  while the inner sub-sleeve  60   b  is deployed over the probe tip  30  or the inner sub-sleeve  60   b  and the outer sub-sleeve  60   a  may both be deployed from the hand piece  105  and over the probe tip  30  in a telescoping manner. Notably, the matching gauge size of the cannula  42  and the inner sub-sleeve  60   b  provides a substantially flush-fit engagement therebetween with minimal play, thus affording the surgeon optimal control of the probe tip  30  within the eye. As used herein with respect to the insertion of a component (e.g., the probe tip  30 , the sleeve  60 , the inner sub-sleeve  60   b , or the outer sub-sleeve  60   a ) into the cannula  42  or other surgical point of entry, a flush-fit engagement shall be understood to mean an engagement in which the outer diameter of the component is substantially flush with the inner diameter of the cannula  42  while still allowing the component to be freely inserted into or retracted from the cannula  42 . 
       FIG. 5D  illustrates yet another exemplary use of the embodiment  500  with the cannula  42 . In this exemplary use, the cannula  42  is sized at 23 gauge, the probe tip  30  is sized at 27 gauge, the inner sub-sleeve  60   b  is sized at 25 gauge, and the outer sub-sleeve  60   a  is sized at 23 gauge. Since the gauge size (23 gauge) of the outer sub-sleeve  60   a  matches that of the cannula  42 , the outer sub-sleeve  60   a  may be inserted through the cannula  42 , realizing a substantially flush-fit engagement of the outer sub-sleeve  60   a  and the cannula  42 . The inner sub-sleeve  60   b  may remain within the outer sub-sleeve  60   a , as shown in  FIG. 5D , such as in a case in which the inner sub-sleeve  60   b  and the outer sub-sleeve  60   a  were both deployed together from the hand piece  105 . In other configurations of the embodiment  500  (not shown in  FIG. 5D ), the inner sub-sleeve  60   b  may be further deployed in a telescoping fashion from the outer sub-sleeve  60   a  and over the probe tip  30  towards the distal end  50 . 
     It will be appreciated that the foregoing description provides examples of the disclosed system and technique. However, it is contemplated that other implementations of the disclosure may differ in detail from the foregoing examples. All references to the disclosure or examples thereof are intended to reference the particular example being discussed at that point and are not intended to imply any limitation as to the scope of the disclosure more generally. All language of distinction and disparagement with respect to certain features is intended to indicate a lack of preference for those features, but not to exclude such from the scope of the disclosure entirely unless otherwise indicated. 
     Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context.