Abstract:
A muscle stimulator that may be used during ARM surgeries is disclosed that may be constructed from (1) a widely available low cost (e.g., $200 per unit) peripheral nerve stimulators or similar stimulator and (2) a relatively simple, handheld surgical probe to provide a low cost muscle stimulator that is adequate for ARM surgeries. These two components could provide a low cost solution to allow doctors in developing countries feasibly perform ARM surgeries with relatively minimal manufacturing and inexpensive maintenance.

Description:
FIELD OF THE INVENTION 
       [0001]    The claimed invention relates to devices and methods for the stimulation of a patient&#39;s muscles using a probe. 
       BACKGROUND 
       [0002]    Anorectal malformations are variety birth defects that may include (1) the absence of an anal opening, (2) the anal opening in the wrong place, (3), a connection, or fistula, joining the intestine and the urinary system, (4) a connection joining the intestine and vagina, or (5) the intestine can join with the urinary system and vagina in a single opening. During repair of the anorectal malformations, the colon is pulled down to a newly created anal opening, which must be properly situated between the anal sphincter muscles. Repair of anorectal malformations (ARM) using either posterior sagittal anorectoplasty (PSARP) or Georgeson&#39;s laparoscopic technique is optimally performed using a muscle stimulator to clearly delineate the anal and pelvic muscle complexes for precise anatomic placement of the rectal pull-through segment. Unfortunately, commercially available muscle stimulators for ARM surgery can be prohibitively expensive for many regions of the globe due as their cost may exceed 10,000 USD. Not surprisingly, this cost barrier limits the use of this critically important tool by surgeons in communities with limited resources to purchase this device. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0003]    Exemplary embodiments are illustrated in referenced figures. It is intended that the embodiments and figures disclosed herein are to be considered illustrative rather than restrictive. 
           [0004]      FIG. 1  depicts, in accordance with various embodiments of the present invention, a cross sectional view of a probe and stimulator; 
           [0005]      FIG. 2  depicts, in accordance with various embodiments of the present invention, a top view of a probe and stimulator; and. 
           [0006]      FIG. 3  depicts, in accordance with various embodiments of the prevent invention, a method for performing a surgery with the disclosed devices. 
       
    
    
     SUMMARY OF THE INVENTION 
       [0007]    Through various forms of experimentation, the inventors have determined that a suitable muscle stimulator may be constructed from (1) a widely available low cost (e.g., $200 per unit) peripheral nerve stimulators or similar stimulator and (2) a relatively simple, handheld surgical probe to provide a low cost muscle stimulator that is adequate for ARM surgeries. These two components could provide a low cost solution to allow doctors in developing countries feasibly perform ARM surgeries with minimal cost and manufacturing. Furthermore, a simple and durable probe stimulator may be easily detached from the device and sterilized using a steam (e.g. autoclave) sterilization procedure that is harsh but inexpensive. This is a drastic improvement over current muscle stimulators which have complex probes that cannot be steam sterilized and therefore require sterilization at a centralized hospital using potentially time intensive procedures. 
       Stimulator 
       [0008]    In some embodiments, a commercially available “Peripheral Nerve Stimulator” commonly designed for use as a tool for anesthesiologists to determine the appropriate sedation levels for a given patient during surgery may be utilized to provide the appropriate electrical stimulation. There are various manufacturers of these devices, and they typically consist of an electronic device that is battery operated with some type of user interface controlling the amount of current that is delivered through various forms of metallic external connectors to the patient. The stimulator is activated through a button that delivers electrical current from the stimulator when depressed. 
       Probe 
       [0009]    The second component of the presently disclosed device is the handheld surgery probe that may include a probe tool and an electrical connection to the stimulator that delivers the electrical current from the stimulator to the patient&#39;s skin. In some embodiments, such a handle held probe may include an electrically insulated handle with two metallic leads that protrude through the top of the device and deliver the electrical stimulation to a patient&#39;s skin. The probe may include a handle portion or casing that is made of an electrically insulating material to prevent the flow of current between the two metallic leads when not in contact with the patient&#39;s skin. The probe could be constructed from a material that can endure sterilization temperatures and is resistant to corrosion caused by the steam sterilization. 
         [0010]    In some embodiments, the probe is connected to the stimulator through a pair of electrically insulated wires that connect from metallic leads on the pen probe to the two pins on the stimulator. The wires connecting the pen probe to the stimulation device may also be made of heat resistant and corrosion resistant materials so that the entire surgery probe unit can be separated from the stimulator device and sterilized and reused for multiple surgeries. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0011]    All references cited herein are incorporated by reference in their entirety as though fully set forth. Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. One skilled in the art will recognize many methods and materials similar or equivalent to those described herein, which could be used in the practice of the present invention. Indeed, the present invention is in no way limited to the methods described herein. For purposes of the present invention, the following terms are defined below. 
       Overview 
       [0012]      FIG. 1  illustrates an embodiment of the present disclosure that includes a simulator  100  and a probe  105 . The stimulator  100  may be connected to the probe  105  through a wire  130  and connector  150  or directly with just a wire  130 . The probe  105  includes an electrically insulated casing  110  that house two leads  120  that conduct electricity to the patient&#39;s skin or soft tissue in order to stimulate muscles and/or nerves. In some embodiments, the leads  120  may contain a spacer  140  to ensure separation of the two leads  120  on the patient&#39;s skin. 
         [0013]    During usage for example in an ARM surgery, a surgeon may place the probe leads  120  on a patient&#39;s skin and activate the simulator  100  to deliver a sufficient amount of electricity to a localized area in order to cause a contraction of muscle in the vicinity of the probe leads  120 . If sufficiently electricity is delivered, the surgeon or a detector (for example with an EMG device) may record muscle contractions. Thus the surgeon will then be able to determine the location of certain muscles. For example, the device may be utilized to detect the location of the anal and pelvic muscles, so an appropriate placed incision can be made for the ARM surgery. If a contraction is detected, the intensity and direction of contraction will provide a surgeon or other caregiver with information regarding the location and orientation of muscles. 
       Stimulator 
       [0014]    In some embodiments, stimulator  100  may be a conventional “Peripheral Nerve Stimulator” commonly designed for use as a tool for anesthesiologists to determine the appropriate sedation levels for a given patient during surgery. For example, the commercially available Micro Stim or SunStim peripheral nerve stimulators may be implemented. In other embodiments, any suitable stimulator  100  may be utilized that delivers an appropriate electrical pulse to two different leads as described herein. 
         [0015]    The stimulator  100  may deliver a suitable pulse to cause contraction of muscles with a certain range of the leads  120  of the probe  105 . For instance, the stimulator  100  may deliver a constant mode 100 Hz square wave that ranges between 0-70 milliamps. In other embodiments, other shapes of waves may be utilized that various in amplitude and frequency. In some embodiments, the amplitude may be varied to compensate for different ages of patients&#39; that require a different threshold of stimulation to contract local muscles. The amplitude of current may also determine the maximum distance from the leads  120  that will precipitate muscular contraction. In some embodiments, the stimulator  100  may be able to vary the amplitude to allow a doctor to customize the pulse for a particular patient. 
         [0016]      FIG. 2  illustrates an embodiment of the stimulator  100  including the available options for waveforms. As illustrated, the options available for stimulation are relatively basic and include a 100 Hz and TDF wave. 
       Probe 
       [0017]    The probe  105  may be simply constructed from durable materials in order to allow for harsher sterilization methods that may be employed in developing countries. For instance, the probe  105  may include leads  120  for delivering the electrical current to a patient&#39;s skin from the wires  130 . In some embodiments, the leads  120  may be elongated rods constructed of corrosion resistant metal or other conductors. In some embodiments, the leads  120  may be constructed from brass rods. In some embodiments, the ends of the leads  120  may be rounded at the tip  125  to avoid damaging a patient&#39;s skin. In some embodiments, the leads  120  may be 2-5 inches, 4 inches, 3 inches, 2 inches, or 1 inch, or other suitable lengths.  FIG. 2  illustrates an embodiment of probe  105  that includes a relatively straight casing  110 . 
         [0018]    As illustrated in  FIG. 1 , casing  110  or other electrical insulating covering may enclose the leads  120  for handling by the physician and for preventing current from exiting the leads other than at the tip portion  125  of the leads. Various materials may be utilized for casing  110  that are preferably resistant to corrosive methods of sterilization, durable, and provide electrical insulation. For example, a polytretrafluoroethylene (PTFE) tube may be utilized, with holes or a channel for the leads  120  to be inserted through. In other embodiments, other materials may be utilized that are suitable. 
         [0019]    In some embodiments, the casing  110  will have a channel  160  or hole that runs the longitudinal length of the tube. The leads  120  may be inserted through the hole and then a spacer  140  provided near the tip  125  to keep the leads  120  separated from each other. In some embodiments, spacer  140  may run the length of the casing  110 , a third of the casing  110 , or may be placed between the two leads  120 . In other embodiments, the leads  120  may be glued to the side or spacer  140  with a cement or adhesive. In some embodiments, a filler may be packed into the hole  160  that could harden and keep leads  120  in place. In some embodiments, to lengthwise holes  160  may be drilled, machined, or otherwise made that are sized to fit leads  120 . Casing may be rounded or sanded on the end nearest the tip  125  of the probes  120  to avoid a sharp protrusion. 
         [0020]    The probes may be connected to connectors  150  or stimulator  100  through wires  130 . Wires  130  may be any suitable wires that are resistant to certain types of corrosive and/or harsh sterilization techniques. For instance, 24 AWG, stranded wire may be utilizes that is rated for high heat, for example up to 150 C, 160 C, 170 c, or 200 C, and 600V with FEB insulation. The wire  130  may be connected to probe  120  and connector  150  by any suitable connection, including for example wrapping and soldering the wire to the leads  120  and the connector. In other embodiments, simple heat shrink tubing may additionally or alternatively be utilized that is rated for 140 C, 150 C, 160 C or other suitable temperatures. 
       Methods 
       [0021]    The device as presently disclosed may be utilized for the stimulation of muscles during surgeries or in other appropriate contexts. For example, the stimulator  100  and probe  105  may be utilized to perform (1) repair of anorectal malformations (ARM) or (2) precise identification of facial nerve branches when performing head and neck surgery. Other examples and methods of utilizing a probe and stimulator as disclosed herein may be utilized for the stimulation of muscles of a patient. 
         [0022]    Repair of anorectal malformations (ARM) using either posterior sagittal anorectoplasty (PSARP) or Georgeson&#39;s laparoscopic technique are optimally performed using a muscle stimulator to clearly delineate the anal and pelvic muscle complexes for precise anatomic placement of the rectal pull-through segment. Examples of these operations are described in detail in: Georgeson K E, Inge T H, Albanese Conn. (2000) Laparoscopically-assisted anorectal pull-through for high imperforate-anus—a new technique. J. Pediatr. Surg. 35:927-931. 
         [0023]    Operations in which the identification of nerve branches is essential to safe operation include superficial parotidectomy and complete parotidectomy particularly in cases of parotid tumors. An example of this surgery is described in: Spiro R H., The parotid gland. In Baker R J, Fischer J E, eds. Mastery of Surgery. Vol. 14th ed. Philadelphia: Lippincott Williams &amp; Wilkins; 2001: 320-327; and Pena A (1988) Posterior Sagittal anorectoplasty: results in the management of 332 cases of anorectal malformations. Pediatr. Surg. Int. 3:94-104. 
         [0024]      FIG. 3  illustrates an example of a method disclosed herein for utilizing the disclosed stimulating system. The methods disclosed may include providing a stimulator  100  that may be a conventional peripheral nerve stimulator, providing a probe as described herein. The stimulator  100  may be connected  200  to the probe  105  through a wire  130  and connector  150  or directly with just a wire  130 . 
         [0025]    The probe  105  and stimulator  100  may be utilized to map out the limits of the anal and pelvic muscle complexes for precise anatomic placement of the rectal pull-through segment. Accordingly, the probe  105  includes an electrically insulated casing  110  that house two leads  120  that conduct electricity to the patient&#39;s skin or soft tissue in order to stimulate muscles and/or nerves. In some embodiments, the leads  120  may contain a spacer  140  to ensure separation of the two leads  120  on the patient&#39;s skin. 
         [0026]    During usage, for example in an ARM surgery, a surgeon may place the probe leads  120  on a patient&#39;s skin or soft tissue  210  and activate the simulator  220  to deliver a sufficient amount of electricity to a localized area in order to cause a contraction of muscle in the vicinity of the probe leads  120 . If sufficiently electricity is delivered, the surgeon or a detector (for example with an EMG device), may record muscle contractions  230 . Thus, the surgeon will then be able to determine the location of certain muscles. For example, the device may be utilized to detect the location of the anal and pelvic muscles, so an appropriate placed incision can be made for the ARM surgery. If a contraction is detected, the intensity and direction of contraction will provide a surgeon or other caregiver with information regarding the location and orientation of muscles. After a contraction is detected  230 , the surgeon may relocate the probe on the patient  240  and repeat the process to map out the limits of the anal and pelvic muscles. 
       CONCLUSIONS 
       [0027]    The various methods and techniques described above provide a number of ways to carry out the invention. Of course, it is to be understood that not necessarily all objectives or advantages described may be achieved in accordance with any particular embodiment described herein. Thus, for example, those skilled in the art will recognize that the methods can be performed in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objectives or advantages as may be taught or suggested herein. A variety of advantageous and disadvantageous alternatives are mentioned herein. It is to be understood that some preferred embodiments specifically include one, another, or several advantageous features, while others specifically exclude one, another, or several disadvantageous features, while still others specifically mitigate a present disadvantageous feature by inclusion of one, another, or several advantageous features. 
         [0028]    Furthermore, the skilled artisan will recognize the applicability of various features from different embodiments. Similarly, the various elements, features and steps discussed above, as well as other known equivalents for each such element, feature or step, can be mixed and matched by one of ordinary skill in this art to perform methods in accordance with principles described herein. Among the various elements, features, and steps some will be specifically included and others specifically excluded in diverse embodiments. 
         [0029]    Although the invention has been disclosed in the context of certain embodiments and examples, it will be understood by those skilled in the art that the embodiments of the invention extend beyond the specifically disclosed embodiments to other alternative embodiments and/or uses and modifications and equivalents thereof. 
         [0030]    In some embodiments, the numbers expressing quantities of ingredients, properties such as concentration, reaction conditions, and so forth, used to describe and claim certain embodiments of the invention are to be understood as being modified in some instances by the term “about.” Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the invention may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements. 
         [0031]    In some embodiments, the terms “a” and “an” and “the” and similar references used in the context of describing a particular embodiment of the invention (especially in the context of certain of the following claims) can be construed to cover both the singular and the plural. The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual 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. The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention. 
         [0032]    Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all Markush groups used in the appended claims. 
         [0033]    Preferred embodiments of this invention are described herein, including the best mode known to the inventor for carrying out the invention. Variations on those preferred embodiments will become apparent to those of ordinary skill in the art upon reading the foregoing description. It is contemplated that skilled artisans can employ such variations as appropriate, and the invention can be practiced otherwise than specifically described herein. Accordingly, many embodiments of this invention include all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context. 
         [0034]    Furthermore, numerous references have been made to patents and printed publications throughout this specification. Each of the above cited references and printed publications are herein individually incorporated by reference in their entirety. 
         [0035]    In closing, it is to be understood that the embodiments of the invention disclosed herein are illustrative of the principles of the present invention. Other modifications that can be employed can be within the scope of the invention. Thus, by way of example, but not of limitation, alternative configurations of the present invention can be utilized in accordance with the teachings herein. Accordingly, embodiments of the present invention are not limited to that precisely as shown and described.