Claims:1. A system for real-time measurement of a force, the system comprises:
(a) a sensing component comprising:
a sensing bar;
a Fiber Bragg Grating (FBG) sensor affixed to at least a part of said sensing bar; and
at least a pair of support members to hold said sensing bar there between;
wherein, at least one support member of said at least a pair of support members comprises a means to operatively couple a tissue traversing member therewith;
(b) at least one interrogator operatively coupled to said sensing component to provide a value corresponding to said force transmitted by said tissue traversing member to said sensing component while traversing a tissue;
wherein, said sensing component is at least partially enclosed in a casing to provide only one degree of freedom to said sensing component.
2. The system of claim 1, wherein said system measures axial force exerted on said tissue traversing member.
3. The system of claim 1, wherein said system substantially eliminates effect of a bending force exerted on said tissue traversing member while taking measurement of said force.
4. The system of claim 1, wherein said at least one interrogator comprises a FBG interrogator.
5. The system of claim 1, wherein said means to operatively couple a tissue traversing member comprises any or a combination of a groove, a locking member and a fixture.
6. A system for real-time measurement of a force exerted on a spinal needle while traversing a tissue, the system comprises:
(a) a sensing component comprising:
a sensing bar;
a Fiber Bragg Grating (FBG) sensor affixed to at least a part of said sensing bar; and
at least a pair of support members to hold said sensing bar there between;
wherein, at least one support member of said at least a pair of support members comprises a means to operatively couple a spinal needle therewith;
(b) at least one interrogator operatively coupled to said sensing component to provide a value corresponding to said force transmitted by said spinal needle to said sensing component while traversing a tissue;
wherein, said sensing component is at least partially enclosed in a casing to provide only one degree of freedom to said sensing component to substantially eliminate effect of a bending force exerted on said spinal needle while taking measurement of said force.
7. The system of claim 6, wherein said at least one interrogator comprises a FBG interrogator.
8. The system of claim 1, wherein said means comprises any or a combination of a groove, a locking member and a fixture.
9. A method of estimating a compressive force exerted on a spinal needle while traversing a tissue, the method comprises the steps of:
operatively coupling the spinal needle to a sensing component comprising a sensing bar, a Fiber Bragg Grating (FBG) sensor affixed to at least a part of said sensing bar, and at least a pair of support members to hold said sensing bar there between, wherein said sensing component is at least partially enclosed in a casing to provide only one degree of freedom to said sensing component;
advancing said spinal needle to traverse said tissue;
sensing the compressive force exerted on said spinal needle by said sensing component while traversing said tissue; and
providing input to an interrogator corresponding to the sensed compressive force to estimate a compressive force exerted on said spinal needle while traversing said tissue.
10. The method of claim 9, wherein said method estimates the compressive force in real-time.
11. The method of claim 9, wherein said method eliminates effect of bending force exerted on said spinal needle while estimating said compressive force.
, Description:TECHNICAL FIELD
The disclosure generally relates to biomedical field. In particular, the present disclosure pertains to a system and method(s) for monitoring the real-time dynamic force experienced by a tissue traversing member while traversing a tissue using a Fiber Bragg Grating (FBG) sensor.

BACKGROUND
Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
Clinical practices mostly involve needle insertion procedures which require puncturing of skin tissues. A skilled medical practitioner penetrates the needle through different tissue layers in order to reach to the target location for treatment, optimizing the traverse path of needle by virtue of his own sensory feel of the resistance force. Tissue properties for different individuals vary in terms of thickness, stiffness, firmness etc. In procedures such as biopsy and epidural anesthesia, needle positioning accuracy is highly essential. Many critical cases of medical errors by trainee surgeons and staff have been reported, particularly the accidental puncturing of vital organs during surgeries. Such errors can be prevented with better understanding of needle interaction with surrounding tissues by imparting essential surgical skills training assisted with advanced technical tools. Also, it is imperative to know the real-time positioning of the spinal needle during the lumbar puncture procedure which is utilized for several diagnostic and therapeutic medical practices involving collection of cerebrospinal fluid (CSF) or reduction of increased intracranial pressure. The most common issue persisting in this methodology is Post-Dural-Puncture Headache (PDPH).
Significant efforts have already been made across the globe to develop new techniques and systems that can enhance the accuracy of clinicians while performing needle insertion procedures.
At present, a number of techniques are available that use different strategies and methods to measure the positioning and imaging of needle during such invasive procedures. These include, 1) a force feedback monitoring of needle insertion involving robotic surgery or minimally invasive surgeries using haptic feedback mechanism, 2) a mechanical actuator based techniques that can simulate a haptic experience similar to penetrating tissue with a needle using brushless motors supported force feedback system, 3) needle insertion force measurement using bevel-tip needle mounted on a digital force gauge which provides the needle insertion forces used to model the consistency of the tissues in the lumbar region of the back, 4) haptic force feedback monitoring using a hardware and software based haptic device and simulation methodology, 5) epidural hardware and software based simulators for force feedback monitoring.
The abovementioned techniques and procedures employ complex systems and bulky sensors for estimation of needle insertion force severely limiting their practical applications. Further, the force(s) measured by these techniques and instruments are not accurate owing to inclusion of bending force(s) experienced by the needle during insertion.
Overbeek et al (University of Twente, BSc Report, June 2013) proposed measurement of force(s) acting on the tip of the needle by mounting multiple (three to be specific) FBG sensors length-wise onto the needle with an assumption that fibers (FBGs) are exactly 120 degrees apart and at an equal length from the center. The proposed models and hypothesis can compensate for bending forces experienced by multiple FBG sensors owing to their accurate positioning. However, any deviation in positioning of sensors onto the needle can give rise to serious errors i.e. in case the sensors are not exactly 120 degrees apart, bending will influence the strain measured and will give an altered picture of the axial strain acting upon the needle. This requirement complicates the manufacturing of the device to an extent that it can be viewed as practically non-viable.
Abolhassani et al (Medical Engineering & Physics 2007, 29, 413–431) discloses a survey presenting current state of research on needle insertion in soft tissue that covers several aspects including modelling of needle insertion forces, modelling of tissue deformation and needle deflection during insertion, robot-assisted needle insertion, and the effect of different trajectories on tissue deformation. However, it fails to disclose any real-time force measuring feedback system with capability to alleviate effects of bending during needle insertion.
US publication US20110288405A1 discloses a rigid hollow needle having an end portion coupled to a first fiber optic cable, a first light source, and a first optical sensing stress sensor that can measure the pulsatile motion of fluids in a multi-second time period and in substantially real-time while inserting the end portion into a patient. However, it fails to disclose a system that can alleviate/compensate bending forces operative during needle insertion.
US publication US20150018840 discloses a decoupled 2-DOF MRI-compatible sensor to measure axial torque and force. However, avoidance of bending due to axial force requires one arm of the robot to be kept constant to avoid inaccuracy in force measurement.
US publication US20150164598A1 discloses an apparatus, system, and method for improving force and torque sensing and feedback to the surgeon performing a telerobotic surgery using a FBG sensor that eliminates the errors due to changes in the configuration of the tip or steady state temperature variations. However, it fails to disclose the real-time force measuring system with alleviation/compensation of bending effects.
After careful scrutinization of these documents amongst others, a person skilled in the art would immediately realize one or more drawbacks associated with such systems and methods, limiting their practical applications. There is therefore, a need to develop a system and method(s) for monitoring the real-time dynamic force experienced by a spinal needle during lumbar puncture procedure using a Fiber Bragg Grating (FBG) sensor by compensating the bending forces exerted on the needle.

OBJECTS OF THE INVENTION
An object of the present disclosure is to overcome one or more disadvantages associated with conventional systems and methods for measurement of real-time dynamic force experienced by a tissue traversing member while traversing a tissue.
Another object of the present disclosure is to provide a system and method(s) for real-time measurement of axial forces exerted onto the tissue traversing member while traversing a tissue.
Another object of the present disclosure is to provide a system and method(s) for real-time measurement of axial forces exerted onto the needle without taking into account the bending forces exerted on the needle while its insertion into an anatomic region of the body.
Another object of the present disclosure is to provide a system to increase the accuracy of the spinal needle insertion.
Another object of the present disclosure is to provide a system that enables a user to achieve better control on needle insertion.
Another object of the present disclosure is to provide a system that can reduce the risk of injuries during tissue puncture.
Another object of the present disclosure is to provide a system that does not require the sensing components to be subjected to sterilization.
Various objects, features, aspects and advantages of the present invention will become more apparent from the detailed description of the invention herein below along with the accompanying drawing figures in which like numerals represent like components.

SUMMARY
The disclosure generally relates to biomedical field. In particular, it pertains to a system and method(s) for monitoring the real-time dynamic force experienced by a tissue traversing member while traversing a tissue using a Fiber Bragg Grating (FBG) sensor.
An aspect of the present disclosure provides a system for real-time measurement of a force, the system includes: a sensing component including: a sensing bar; a Fiber Bragg Grating (FBG) sensor affixed to at least a part of said sensing bar; and at least a pair of support members to hold said sensing bar there between, wherein at least one support member of said pair of support members includes a means to operatively couple a tissue traversing member therewith; at least one interrogator operatively coupled to said sensing component to provide a value corresponding to said force transmitted by said tissue traversing member to said sensing component while traversing a tissue, wherein said sensing component is at least partially enclosed in a casing to provide only one degree of freedom to said sensing component. In an embodiment, said system measures axial force exerted on said tissue traversing member. In an embodiment, said system substantially eliminates effect of a bending force exerted on said tissue traversing member while taking measurement of said force. In an embodiment, at least one interrogator includes a FBG interrogator. In an embodiment, means to operatively couple a tissue traversing member includes any or a combination of a groove, a locking member and a fixture.
Another aspect of the present disclosure provides a system for real-time measurement of a force exerted on a spinal needle while traversing a tissue, the system includes: a sensing component including: a sensing bar; a Fiber Bragg Grating (FBG) sensor affixed to at least a part of said sensing bar; and at least a pair of support members to hold said sensing bar there between, wherein at least one support member of said pair of support members includes a means to operatively couple a spinal needle therewith; at least one interrogator operatively coupled to said sensing component to provide a value corresponding to said force transmitted by said spinal needle to said sensing component while traversing a tissue, wherein said sensing component is at least partially enclosed in a casing to provide only one degree of freedom to said sensing component to substantially eliminate effect of a bending force exerted on said spinal needle while taking measurement of said force. In an embodiment, interrogator includes a FBG interrogator. In an embodiment, means to operatively couple a spinal needle includes any or a combination of a groove, a locking member and a fixture.
Another aspect of the present disclosure relates to a method of estimating a compressive force exerted on a spinal needle while traversing a tissue, the method includes the steps of: operatively coupling the spinal needle to a sensing component including a sensing bar, a Fiber Bragg Grating (FBG) sensor affixed to at least a part of said sensing bar, and at least a pair of support members to hold said sensing bar there between, wherein said sensing component is at least partially enclosed in a casing to provide only one degree of freedom to said sensing component; advancing said spinal needle to traverse said tissue; sensing the compressive force exerted on said spinal needle by said sensing component while traversing said tissue; and providing input to an interrogator corresponding to the sensed compressive force to estimate a compressive force exerted on said spinal needle while traversing said tissue. In an embodiment, said method estimates the compressive force in real-time. In an embodiment, said method eliminates effect of bending force exerted on said spinal needle while estimating said compressive force.
Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.
FIG. 1 illustrates an exemplary exploded view of sensing component of Fiber Bragg Grating Force Device (FBGFD) in accordance with embodiments of the present disclosure.
FIG. 2 illustrates an exemplary view of spinal needle fixture in accordance with embodiments of the present disclosure.
FIG. 3 illustrates an exemplary view of Fiber Bragg Grating Force Device (FBGFD) in accordance with embodiments of the present disclosure.
FIG. 4A illustrates an exemplary disassembled view of Fiber Bragg Grating Force Device (FBGFD) in accordance with embodiments of the present disclosure.
FIG. 4B illustrates an exemplary assembled view of Fiber Bragg Grating Force Device (FBGFD) in accordance with embodiments of the present disclosure.
FIG. 5 illustrates an exemplary view of a Mecmesin's micro Universal Testing Machine (UTM) and FBGFD assembly for calibration test in accordance with embodiments of the present disclosure.
FIG. 6A illustrates an exemplary graph depicting force measured by the FBGFD in comparison to force measured by the UTM in accordance with embodiments of the present disclosure.
FIG. 6B illustrates an exemplary FBGFD calibration curve in accordance with embodiments of the present disclosure.
FIG. 7A illustrates an exemplary view of a cadaver lumbar puncture procedure using FBGFD in accordance with embodiments of the present disclosure.
FIG. 7B illustrates a closer view of a cadaver lumbar puncture procedure using FBGFD in accordance with embodiments of the present disclosure.
FIG. 8 illustrates an exemplary graph depicting FBGFD force response during tissue penetration in accordance with embodiments of the present disclosure.
FIG. 9 illustrates an exemplary graph depicting FBGFD force response during bone encounter in accordance with embodiments of the present disclosure.

DETAILED DESCRIPTION
The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the “invention” may in some cases refer to certain specific embodiments only. In other cases it will be recognized that references to the “invention” will refer to subject matter recited in one or more, but not necessarily all, of the claims.
As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
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.
Various terms as used herein are shown below. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.
The disclosure generally relates to biomedical field. In particular, the present disclosure pertains to a system and method(s) for monitoring the real-time dynamic force experienced by a tissue traversing member while traversing a tissue using a Fiber Bragg Grating (FBG) sensor.
Fiber Bragg Grating (FBG) is a periodic modulation of the refractive index of the core of a single mode photosensitive optical fiber along its axis. In an embodiment, FBGs are photo-inscribed by exposing the core of a photosensitive germano-silicate fiber to an interference pattern created using a 248nm UV laser beam through a phase mask. When a broadband light is launched into a FBG, one particular wavelength (?B) which satisfies the Bragg condition is reflected back and rest all wavelengths are transmitted through the fiber. The reflected Bragg wavelength from the FBG is given by
?_B=2n_eff ? (1)
The Bragg resonance wavelength ?B, is the free space centre wavelength of the input light that will be back-reflected from the Bragg grating. Here, neff is the effective refractive index of the fiber and ? is the spacing between the gratings. In a preferred embodiment, FBG sensors with a gauge length of 3mm can be fabricated in photo sensitive germania doped silica fibers, using the phase mask grating inscription method. It can be seen from equation-1 shown above that the reflected Bragg wavelength depends on the effective refractive index of the fiber (neff) and the periodicity of the grating (?). The strain effect on an FBG sensor can be expressed as
??_B ?=??_B [1-(n_eff^2)/2 [p_12-v(p_11+p_12 ) ] ] e_z (2)
Where, P11 and P12 are components of the strain-optic tensor, v is the Poisson’s ratio and E is the axial strain change. The strain sensitivity of a FBG inscribed in a germania-doped silica fiber is approximately 1.20 pm/µE. In alternative embodiments, FBG sensors realized with any other methods known to a person skilled in the art can be utilized to serve its intended purpose. As the temperature variations may also cause a shift in the Bragg wavelength, it is imperative to compensate for temperature variations (if any) while using the FBG sensor for strain measurements. Since strain measurements can be carried out within a short duration of time and in controlled environmental condition, where temperature change are negligibly small, the temperature effect on the FBG sensor can be ignored.
An aspect of the present disclosure provides a system for real-time measurement of a force, the system includes: (a) a sensing component including: a sensing bar; a Fiber Bragg Grating (FBG) sensor affixed to at least a part of said sensing bar; and at least a pair of support members to hold said sensing bar there between, wherein at least one support member of said pair of support members includes a means to operatively couple a tissue traversing member therewith; (b) at least one interrogator operatively coupled to said sensing component to provide a value corresponding to said force transmitted by said tissue traversing member to said sensing component while traversing a tissue, wherein said sensing component is at least partially enclosed in a casing to provide only one degree of freedom to said sensing component. In an embodiment, said system measures axial force exerted on said tissue traversing member. In an embodiment, the system substantially eliminates effect of a bending force exerted on said tissue traversing member while taking measurement of said force. In an embodiment, at least one interrogator includes a FBG interrogator. In an embodiment, means to operatively couple a tissue traversing member includes any or a combination of a groove, a locking member and a fixture.
In an embodiment, sensing bar can include any support member of suitable geometry to serve its intended purpose of providing support to the FBG sensor (fiber) affixed therewith. In an embodiment, FBG sensor can be affixed with the sensing bar utilizing any suitable means known to a person skilled in the art including but not limited to by application of heat and/or pressure, by means of adhesive and the like. In an embodiment, a pair of support members can be utilized to hold sensing bar there between. The support member can be made of any suitable material with rigidity sufficient to hold said sensing bar there between. In an embodiment, said support members can be made of any metallic material. Most preferably, said support members can be made of stainless steel. The support members can be of any geometry known to a person skilled in the art. Most preferably, cylindrical support members made of stainless steel can be utilized to hold said sensing bar there between. In an embodiment, tissue traversing member can include any surgical or diagnostic device including needle, probes, drill bits and the like as known to a person skilled in the art that can advantageously utilize real-time monitoring/measuring system and method(s) realized in accordance with embodiments of the present disclosure.
In an embodiment, the tissue traversing member can be operatively coupled to the sensing component by provision of a suitable means onto said support members as known to a person skilled in the art. Preferably, means to operatively couple a tissue traversing member with the support member, and hence, with the sensing component, includes any or a combination of a groove (opening), a locking member and a fixture. The groove can be of any suitable dimensions and shape to accommodate (preferably, detachably couple) said tissue traversing member. In an embodiment, said tissue traversing member can include a fixture that can snugly fit into said groove (opening). In an embodiment, said fixture can be an integral part of said tissue traversing member. In an alternative embodiment, said fixture can be provided as a separate detachable part as a means to operatively couple said tissue traversing member with the sensing component.
Another aspect of the present disclosure provides a system for real-time measurement of a force exerted on a spinal needle while traversing a tissue, the system includes: (a) a sensing component including: a sensing bar; a Fiber Bragg Grating (FBG) sensor affixed to at least a part of said sensing bar; and at least a pair of support members to hold said sensing bar there between, wherein at least one support member of said pair of support members includes a means to operatively couple a spinal needle therewith; (b) at least one interrogator operatively coupled to said sensing component to provide a value corresponding to said force transmitted by said spinal needle to said sensing component while traversing a tissue, wherein said sensing component is at least partially enclosed in a casing to provide only one degree of freedom to said sensing component to substantially eliminate effect of a bending force exerted on said spinal needle while taking measurement of said force. In an embodiment, interrogator includes a FBG interrogator. In an embodiment, means to operatively couple a spinal needle includes any or a combination of a groove and a locking member.
FIG. 1 illustrates an exemplary view depicting a sensing component 120 of the system, realized in accordance with embodiment of the present disclosure. The sensing component can include a sensing bar 106, a Fiber Bragg Grating (FBG) sensor 110 affixed to at least a part of the sensing bar and a pair of support members (shown as 102, 104 in FIG. 1) to hold said sensing bar 106 there between. The support member 102 can include a means 108 (shown as an opening) to operatively couple a tissue traversing member (with or without fixture) therewith. In an embodiment, the pair of support members can be of any appropriate diameter and length, preferably, with the diameter ranging from 5-15mm and length ranging from 10-20mm, and most preferably, with diameter of 10mm and length of 15mm. In a preferred embodiment, the support members are of cylindrical shape and are made of stainless steel. In a preferred embodiment, the sensing bar 106 has diameter and length in range of 0.5-1.5mm and 30-50mm, respectively. In a most preferred embodiment, the sensing bar has diameter and length of approximately 0.9mm and 40mm, respectively. In an embodiment, the FBG sensor 110 is affixed on the surface of sensing bar 106 by any means known to a person skilled in the art. In an embodiment, FBG sensor 110 can be of any appropriate gauge length. In a preferred embodiment, the FBG sensor has gauge length ranging from 2-4mm. In a most preferred embodiment, the FBG sensor can have gauge of length 3mm. In an embodiment the sensing bar 106 is of appropriate diameter and length. In an embodiment, at least one support member 102 of said pair of support members includes a means 108 to operatively couple a tissue traversing member therewith. The sensing component 120 can be operatively coupled to interrogator 114 by an optical fiber 112.
FIG. 2 illustrates an exemplary view of a fixture 200 for the tissue traversing member (e.g. a spinal needle), realized in accordance with embodiments of the present disclosure. The fixture can include a head 202 and a tail part 204. The tail part 204 can include threads to detachably fit into opening 108 of support member 102. The head part can include a means 206 to house the tissue traversing member (e.g. a spinal needle). In a preferred embodiment, the fixture 200 can include a head 202 and a tail 204 of diameter ranging from 5-15mm and 3-5mm. In a most preferred embodiment, the fixture can include a head part 202 with diameter 10mm and a tail part 204 with diameter 4mm to house a spinal needle. In a preferred embodiment, the means 206 can be a groove or a locking member as known to a person skill in the art to serve its intended purpose of coupling a tissue traversing member therewith. In a most preferred embodiment, the means 206 is a groove. In an embodiment, groove 206 has a depth ranging from 6-10mm. In a preferred embodiment, the groove 206 has a depth of 8mm.
FIG. 3 illustrates an exemplary view of a system 300 (hereinafter referred to as Fiber Bragg Grating Force Device (FBGFD)) with a spinal needle (tissue traversing member) 302 mounted on it, realized in accordance with an embodiment of the present disclosure. The sensing component is housed in a hollow casing 304. In an embodiment, sensing component can be completely or partially housed inside the hollow tube of appropriate dimensions to provide only one degree of freedom to said sensing component (preferably only in axial direction). In a preferred embodiment, the sensing component is housed inside a 70 mm long hollow casing 304 made up of stainless steel with inner diameter 10mm and outer diameter 12mm. The inner diameter of the hollow tube is maintained such that the sensing component is housed perfectly inside it as it restricts any lateral movement of the sensing component allowing it to move only axially. The length of the hollow tube is maintained so as to match the full longitudinal dimension of the sensing component. Both ends of the tube are closed using threaded caps provided with openings (top 306 and bottom 308) for the spinal needle fixture to attach on one side and for routing the optical fiber 112 connecting FBG sensor on the other side. Thus, this mechanism ensures only 1-degree of freedom for the movement of sensing component i.e. only axial movement inside the hollow tube.
During lumbar puncture the spinal needle traverses through different tissue layers of varying stiffness exerting varying resistances for the spinal needle traversal. The working principle of the FBGFD device, realized in accordance with embodiments of the present disclosure, is based on transduction of force experienced by the spinal needle into strain variations monitored by the FBG sensor. The FBGFD facilitates study and analysis of the force required for the spinal needle to penetrate various tissue layers from the skin to the epidural space; this force is indicative of the varied resistance offered by different tissue layers for the spinal needle traversal. In an embodiment, the Fiber Bragg Grating Force Device (FBGFD) evaluate the force experienced by the spinal needle during lumbar puncture procedure, particularly avoiding the bending effect on the spinal needle. In an embodiment, FBGFD evaluate the force on the spinal needle with nullification of the bending effect, provides an efficient force feedback mechanism which may significantly aid during lumbar puncture procedures.
In operation, upon application of force on the spinal needle 302 mounted over the spinal needle fixture, which is attached to the sensing component 120, the compressive force will be axially translated via the spinal needle fixture to the sensing component 120, which further induces a compressive strain (force) on the sensing bar 106. The FBG sensor 110 which is positioned at the center of the sensing bar 106, acquires the compressive strain in terms of shift in Bragg wavelength. The lateral movement of the sensing component due to spinal needle bending is negated by the virtue of hollow casing walls. The reflected Bragg wavelength (the sensed compressive force) is acquired by means of an Interrogator 114 (e.g. Micron Optics Interrogator SM130-700) which has resolution of 1 picometer wavelength shift. The interrogator - 114 provides values corresponding to the sensed compressive force to estimate compressive force exerted on the spinal needle while traversing the tissue.
Another aspect of the present disclosure relates to a method of estimating a compressive force exerted on a spinal needle while traversing a tissue, the method includes the steps of: operatively coupling the spinal needle to a sensing component including a sensing bar, a Fiber Bragg Grating (FBG) sensor affixed to at least a part of said sensing bar, and at least a pair of support members to hold said sensing bar there between, wherein said sensing component is at least partially enclosed in a casing to provide only one degree of freedom to said sensing component; advancing said spinal needle to traverse said tissue; sensing the compressive force exerted on said spinal needle by said sensing component while traversing said tissue; and providing input to an interrogator corresponding to the sensed compressive force to estimate a compressive force exerted on said spinal needle while traversing said tissue. In an embodiment, said method estimates the compressive force in real-time. In an embodiment, said method eliminates effect of bending force exerted on said spinal needle while estimating said compressive force.
In accordance with embodiments of the present disclosure, the FBGFD can be devised taking care of the possibility for sterilization of the detachable Spinal Needle fixture. The FBGFD can be reused for lumbar puncture tests with the replacement of the spinal needle. The continuous feedback force monitoring of the spinal needle traversal helps in correctly determining the regions penetrated and prevents any unwanted further penetration of the spinal needle upon reaching the region looked-for. As the spinal needle reaches the desired location in the epidural space, FBGFD can be detached releasing the spinal needle. Thus, only the spinal needle is left using which a sample of CSF may be extracted from the epidural space for testing and for any further procedures required in surgery. Furthermore, FBGFD with its feedback force monitoring capability may greatly aid in providing a safe method for trainees to perform the lumbar puncture procedure, knowing the region of spinal needle penetration.
While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.

EXAMPLES
Fabrication of FBGFD
Two cylindrical segments each made up of stainless steel (top and bottom) with diameter of 10mm and length of 15mm were joined to a sensing bar with length of 40mm and diameter of 0.9mm as illustrated in Fig 1. The FBG (Fiber Bragg Grating) sensor of gauge length 3mm was bonded over the surface of the sensing bar, as illustrated in Fig 1, to form the sensing component of FBGFD. The sensing component was then housed inside a 70 mm long hollow stainless steel casing of inner diameter 10mm and outer diameter 12mm to restrict any lateral movement of the sensing component and to allow its movement only in axial direction. Both ends of the hollow casing were closed using threaded caps provided with openings for the spinal needle fixture on one side and for routing the optical fiber connecting FBG sensor on the other side as illustrated in Fig 3. A Spinal Needle fixture with head part diameter 10mm, tail part diameter 4mm and a groove provided on the head part with depth of 8mm (as shown in Fig 2) was then mounted onto the sensing component of FBGFD as illustrated in FIG. 4A and FIG. 4B. The BD spinal needle with Quincke type point of 18GA 3.50IN (1.2mm×90mm) was finally mounted to the FBGFD.
Calibration of the Device
The realized FBGFD was then calibrated using a Mecmesin's micro Universal Testing Machine (UTM) for a range of applied forces. For calibration, the FBGFD was allowed to stand upright on a fixture for compressive force measurement as illustrated FIG. 5. The spinal needle fixture was then put in direct contact with the UTM force device. The UTM was programmed to travel vertically at a rate of 1mm/min with application of force on FBGFD from the spinal needle fixture end. Bragg wavelength shift of the FBG sensor of FBGFD due to progressive application of force from UTM was continuously monitored and recorded.
FIG. 6A illustrates the comparison of force monitored by the UTM and the corresponding strain from the FBG sensor. Both FBG response and UTM response were found to be in good agreement with each other in the investigated ranges of force. Further, the strain experienced by FBGFD exhibited a linear response for the range of applied force demonstrated with the obtained correlation coefficient of 0.99 as illustrated in FIG 6B. For a maximum applied force of 19.3N, the compressive strain in the FBGFD was found to be 733µ?, thus demonstrating FBGFD sensitivity of -38µ?/N. Further, it could be observed that the FBGFD sensitivity is inversely proportional to the thickness of the sensing bar i.e. as thickness of the sensing bar increases, sensitivity of the device reduces.
Validation of the Device
Forces experienced by a spinal needle while its introduction into the sub-arachnoid space of the Thoraco-lumbar spine was quantified by conducting an experiment on a specially embalmed human cadaver specimen that can simulate the organoleptic properties and feel of the live tissue while handling. The Cadaver specimen was positioned in the right lateral position and the inter-spinous spaces was palpated at the Thoraco lumbar junction and the lumbar spine. The BD spinal needle (with Quincke type point of 18GA 3.50IN (1.2mm×90mm)) mounted to the FBGFD was introduced into the sub-arachnoid space as illustrated in FIG. 7A and FIG. 7B. As the spinal needle penetrates through different tissue layers, the force experienced by it varies due to tissue stiffness that was recorded from FBGFD during the spinal needle traversal. When the spinal needle traverses from region of tissues with lower stiffness to higher stiffness, the tissue resistance increases which generates higher compressive force on the spinal needle recorded by the FBGFD and vice versa. The repeated tests and trials were conducted with spinal needle insertion in different directions and pace in order to monitor the varying forces on spinal needle. Also multiple attempts of puncturing with spinal needle were made with 18 gauge spinal needles at multiple levels from T12 - L1 to L4 - L5.
All the validation experiments were carried out by an experienced medical practitioner by progressive insertion of spinal needle, while performing a lumbar puncture procedure on a human cadaver specimen. During the procedure, the dynamic force variations experienced by the spinal needle was recorded from the FBGFD. The dynamic force variations over the spinal needle were then converted to strain variation and continuously recorded from the FBGFD during the lumbar puncture procedure. The varying force experienced by the spinal needle upon full length traversal through skin to epidural space puncturing various tissue layers during lumbar puncture is depicted in FIG. 8, wherein 802 shows needle insertion, 804 shows skin puncture, 806 shows needle traversing supraspinous and interspinous ligaments, 808 shows needle traversing ligamentum flavum and dura mater and 810 shows withdrawal of force on needle. The force response from the FBGFD was quantified with respect to time during the performance of the lumbar puncture. Before the insertion of the spinal needle into the lumbar area, there was no force experienced on the spinal needle as observed by the 0N force response. Compressive force monitored during spinal needle traversal inside specimen is marked with the dotted lines in FIG. 8. The spinal needle insertion initiates with the encounter of skin opposing its penetration with a resistive force creating a compressive force on it. A peak force of 4.27N was recorded at which skin punctures allowing the needle to enter into the cadaver specimen, as observed in FIG. 8. With continued traversal of the spinal needle, the force experienced on it decreases due to the lesser resistance offered by the tissue layers beneath the skin layer. Further, the spinal needle at the Supaspinous and Interspinous Ligament region experienced higher resistance and hence a force of 3.5N was recorded during piercing this region. The sudden decrease in the force on the spinal needle as observed in FIG. 8, indicates that the specific tissue being punctured and the spinal needle’s progression into the next tissue layer. As the spinal needle traverses further the resistances offered by the tissue layers are lower when compared to the initial tissue layers beneath the skin. This shows that the tissue layers beneath the skin are stiffer than the tissue layers in the Supaspinous and Interspinous Ligament region. A force of 2.2N was recorded on the spinal needle which represents the piercing of the Ligamentum flavum and Dura mater and the entrance of the spinal needle into the epidural space, as observed from FIG. 8. Upon reaching the epidural space, the resistance offered to the spinal needle drastically decreases, which was also sensed by the medical practitioner who was performing the procedure. As the spinal needle entered the epidural space, the insertion process was stopped which was observed as the force on the spinal needle returning towards the zero baseline, depicting the end of lumbar puncture procedure.
Another lumbar puncture test was performed on the same cadaver specimen, from different directions and response for the same is depicted in FIG. 9, wherein 902 shows needle insertion, 904 shows skin puncture, 906 shows needle encountering bone (bone hit force), 908 shows needle withdrawal, 910 shows needle re-insertion, 912 shows skin puncture force, 914 shows needle traversing supraspinous and interspinous ligaments, 916 shows needle traversing ligamentum flavum and dura mater and 918 shows withdrawal of force on needle. It was observed that the force on the spinal needle increases with the traversal after the puncturing of the skin layer. The force on the spinal needle increased to 11.45N, which was due to the bone encountered in the traversal path of the spinal needle. As the bone does not allow the spinal needle to pierce through, a high opposing force was observed as indicated by Trial 1 in FIG. 9. As no further insertion of the spinal needle was possible, the medical practitioner had to retrace the spinal needle and begin the procedure again in a different direction.
During the reinsertion of the spinal needle shown as Trial 2 in FIG. 9, the application of force for skin puncturing was carried out at a slower rate. The spinal needle punctured the skin with a force of 4.31 N which was in good agreement with the earlier test performed. Also, the penetration of regions of Supaspinous and Interspinous Ligament along with Ligamentum flavum and Dura mater by the spinal needle, were observed with a force of as 2.2N and 0.8N, respectively. It could further be observed that the resistance offered by the tissue regions to the traversal of the spinal needle also depends on the direction of the spinal needle insertion. Therefore, the forces required to penetrate these regions in the opted pathway of Trial 2 were observed to be lesser than the earlier tests performed. Upon reaching the epidural space, the insertion procedure was halted and the force on the spinal needle returned to the baseline state.
These results proved the efficacy of the developed FBGFD’s employment as a force feedback mechanism during the lumbar puncture tests. The FBGFD responded only to the compressive force acting on the spinal needle negating any bending effect along with any vibrations generated during the insertion procedure. Also, chances of sensor getting damaged are greatly reduced because of the rugged and enclosed structure of FBGFD. This demonstrates its utility in clinical applications for real time force monitoring during spinal needle insertion procedures.

ADVANTAGES OF THE INVENTION
The present disclosure provides for a system and method(s) to overcome one or more disadvantages associated with conventional methods and systems for real-time force measurement during the needle insertion.
The present disclosure provides for a system and method(s) for real-time force measurement during the needle insertion with nullification of the bending effect.
The present disclosure provides for a system and method(s) to collect the sample as the needle is detachable from the assembly/device
The present disclosure provides for a system and method(s) to increase the accuracy of the needle insertion.
The present disclosure provides for a system and method(s) that enable a user to achieve better control on needle insertion.
The present disclosure provides for a system and method(s) that reduce the risk of injuries involving puncturing of the tissue.
The present disclosure provides for a system and method(s) that can be repeatedly utilized with complete sterilization.