1、Designation: F 1266 89 (Reapproved 2002)Standard Performance Specification forCerebral Stereotactic Instruments1This standard is issued under the fixed designation F 1266; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of
2、 last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers stereotactic instruments usedby neurosurgeons to assist in the placement of probes, such a
3、scannulae, needles, forceps, or electrodes or to direct radiationinto brain regions or anatomical targets that are not visible onthe surface. The general location of these regions is determinedby measurements from landmarks visualized by X ray or othermeans, such measurements being based on atlases
4、derivedfrom anatomical studies and autopsy. Because of the anatomi-cal variability, more precise location in any single patient maybe determined by physiological responses in that patient. Thedegree of success in stereotactic surgery depends upon theexperience of the surgeon as well as the precision
5、 of thestereotactic instrument. Nevertheless, minimum standards ofaccuracy for stereotactic instruments that are within the rangeof variability of human anatomy must be maintained.1.2 For the purpose of this specification, a stereotacticinstrument is a guiding device used in human neurosurgery forth
6、e purpose of directing an instrument or treating modality toa specific point within the brain by radiographic or othervisualization of landmarks.1.3 Stereotactic instruments must be constructed to affordthe surgeon reliably reproducible accuracy in placing instru-ments into target areas. Proper posi
7、tioning of the probe is oftenverified by X rays to control errors in calculation and to correctdeflection of the probe during insertion. Physiological param-eters may be used to further define the optimal target.1.4 At the present time, stereotactic instruments are usedmost frequently, but not exclu
8、sively in the following opera-tions. The list is presented only to present examples and shouldnot be construed to restrict advances or developments of newprocedures. For some applications it is not required to hit apoint in space, but to hit a volume or make a lesion within amass. For that purpose,
9、devices other than those covered bythis specification may be employed, but should be restricted tosuch uses:1.4.1 Thalamotomy for parkinsonism and other types oftremor,1.4.2 Electrode implantation for epilepsy,1.4.3 Needle or magnetic insertion, or both, for aneurysmthrombosis,1.4.4 Thalamic or subt
10、halamic operations for dystonia,1.4.5 Thalamic or subthalamic operations for involuntarymovements such as chorea or hemiballismus,1.4.6 Ablation of deep cerebellar nuclei for spasticity,1.4.7 Cingulotomy and thalamic or subthalamic surgery forpain,1.4.8 Mesencephalotomy or tractotomy for pain,1.4.9
11、Ablations of subcortical temporal lobe structures fortreatment of epilepsy,1.4.10 Psychosurgical procedures,1.4.11 Implantation of depth stimulating electrodes for pain,1.4.12 Insertion of forceps or needle for obtaining biopsyspecimens,1.4.13 Foreign body removal,1.4.14 Implantation of radioactive
12、material, and1.4.15 Biopsy or treatment of tumors.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of r
13、egulatory limitations prior to use.2. Referenced Documents2.1 NFPA Standard:NFPA 99 Health Care Facilities Code (56A and 76B-T)22.2 UL Standard:UL 544 Electrical, Medical, and Dental Equipment33. Terminology3.1 Descriptions of TermsThe following descriptions ofterms are for the purposes of this spec
14、ification only. Othernomenclature may be used throughout the literature and byvarious manufacturers:3.1.1 anatomical accuracythe reliability or accuracy withwhich the tip of a probe can be introduced into a givenanatomical target. Because of anatomical variability, a givenanatomical structure or ana
15、tomical target may vary relative tothe position of the reference atlas position of that structure.1This specification is under the jurisdiction of ASTM Committee F04 onMedical and Surgical Materials and Devices and is the direct responsibility ofSubcommittee F04.31 on Neurosurgical Standards.Current
16、 edition approved Nov. 24, 1989. Published January 1990.2Available from National Fire Protection Association (NFPA), 1 BatterymarchPark, Quincy, MA 02269-9101.3Available from Underwriters Laboratories (UL), Corporate Progress, 333Pfingsten Rd., Northbrook, IL 60062.1Copyright ASTM International, 100
17、 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Consequently, it is not possible to relate the reliability of astereotactic apparatus to anatomical accuracy, but only tomechanical accuracy.3.1.2 anatomical targetthat anatomical structure withinthe central nervous sys
18、tem into which it is intended to insert aprobe.3.1.3 anatomic variabilitya variation in position, size orconfiguration of an anatomical structure from one human brainto another.3.1.4 angular accuracythe accuracy to which the probeholder can be adjusted to a given angle from reference planes.3.1.5 an
19、gular scalethe scale on the stereotactic apparatuswhich indicates at which angle the electrode probe holderdirects a probe in relation to one or more reference planes ofthe coordinate system of the apparatus.3.1.6 atlasa topographical map of the brain or spinal cordbased on autopsy studies, used to
20、define the relationshipbetween anatomical structures and landmarks, sometimes in-cluding information about the anatomical variability.3.1.7 direct visualizationthe visualization of an anatomi-cal target by direct visual observation or roentgenographicallywith or without the assistance of air or cont
21、rast material.3.1.8 disconnect systema system to afford adequate accessto the patient.3.1.9 electrodea probe usually insulated except for aspecific portion or portions, commonly the end, which isstereotactically inserted into a desired anatomical target for thepurpose of recording electrical activit
22、y, stimulating nervoustissue, producing a lesion in nervous tissue by passage of adirect or rapidly alternating electrical current, or measuringimpedance.3.1.10 framethat part of the stereotactic apparatus whichis attached to the skull.3.1.11 guide tubea tube through which an electrode orprobe can b
23、e directed to a target. The tube imparts additionalstrength and less likelihood of deviation from a true trajectory.The guide tube can be attached to the electrode probe holder orstereotactic apparatus or attached to the electrode or insertionalprobe in a sleeve-like fashion.3.1.12 landmarka structu
24、re than can be visualized radio-graphically, with or without contrast material or air, fromwhich measurements are made to define the position of thestereotactic target.3.1.13 linear accuracythe positioning accuracy of a linearmovement of the probe holder in the direction of one or moreof the referen
25、ce planes of the stereotactic apparatus.3.1.14 linear scalethe scale on the stereotactic apparatuswhich indicates linear movement of the electrode probe holderin relation to one or more of the reference planes, or a pointwithin the coordinate system.3.1.15 mechanical accuracythe accuracy with which
26、astereotactic apparatus can bring the tip of a straight probe to agiven coordinate within the stereotactic coordinate system.3.1.16 probeany type of long, thin device stereotacticallyinserted into a desired anatomical target. The most commontype of probe is an electrode, but probes can also be cryo-
27、probes, leukotomes, needles, biopsy devices, devices to insertradioactive or other material, magnetic probes, needles orinjection devices, cannulae, forceps, and so forth.3.1.17 probe holderthat part of the stereotactic apparatusthat holds the electrode or probe. It is ordinarily attached to thefram
28、e either directly or indirectly, depending on the type ofapparatus.3.1.18 simulated skullany device to which a stereotacticapparatus might be attached to simulate the stresses imparted tothe apparatus when it is attached to the patients skull. Becauseof the differences in how various stereotactic ap
29、paratus areattached to the skull, no universal simulated skull can bedescribed.3.1.19 stereotactic apparatusany guiding device used inhuman neurosurgery for the purpose of directing a probe intothe brain, under guidance of radiographic visualization oflandmarks, direct radiographic visualization, or
30、 other means.3.1.20 stereotactic targetthat point in space, defined bythe coordinate system of some types of stereotactic apparatus,to which it is desired to insert a probe.3.1.21 undamagedin regard to electrodesnot damagedto an extent where the electrical properties would be affected asto make an e
31、lectrode unacceptable for clinical use.4. Classification of Stereotactic Apparatus4.1 Four basic types of stereotactic instruments, or a com-bination thereof are presently used and will be referred toherein as the arc (polar coordinate), rectilinear type, (c) aimingtype, and (d) interlocking arc typ
32、e. Types with comparable orgreater accuracy should be recognized as they are developed.4.1.1 Arc TypeThe arc type apparatus is constructedaccording to the spherical radius principle so that the targetpoint lies at the center of an arc along which the probe holdermoves so that when a probe inserted i
33、nto the probe holderperpendicular to a tangent of the arc and for a distance equal tothe radius of the arc, the tip of the probe arrives at a singlepoint in space, the center of the circle defined by the arc, thatis, the stereotactic target. This occurs regardless of the positionof the probe holder
34、along the arc or the angle the arc subtendswith the base of the apparatus. Generally, the apparatus isadjusted so that the stereotactic target point corresponds to theanatomical target point, so the probe might be introduced atany angle yet accurately find the stereotactic target.4.1.2 Rectilinear T
35、ypeThe rectilinear type provides indi-vidually for the longitudinal, transverse and vertical move-ments of the probe and probe holder. Ordinarily, a rectilinearstereotactic apparatus also provides for sagittal and transverseangle adjustment as well. Calculations can be made so theprobe can be adjust
36、ed to the scales to aim and advance theprobe to the desired target point along a predeterminedtrajectory.4.1.3 Aiming TypeThe aiming type of stereotactic appa-ratus is attached to a burr hole in the skull. The angles ofinsertion can be adjusted and the depth of insertion of theelectrode or probe con
37、trolled so the probe can be pointed to thedesired target point and then advanced to it.5. Significance and Use5.1 The purpose of a stereotactic apparatus is to guide theadvance of an electrode or other probe accurately and in acontrolled fashion to a given point in space, relative to theF 1266 89 (2
38、002)2apparatus, to the stereotactic target. Thus, when the apparatusis attached to the skull, the electrode or probe can be advancedto a given geographical point within the cranial cavity, near thebase of the skull or in the spinal canal.5.1.1 As generally employed, the ventricles or cavitieswithin
39、the brain or other neurosurgical landmarks are identifiedroentgenographically by other means and, by consulting anatlas or other table, the mean distance and direction betweenthe visualized landmark and a given anatomical target aremeasured. The electrode or probe is then inserted to thestereotactic
40、 target, that is, the point in space which is calculatedfrom the distance and direction between the visualized land-mark and the desired target in relation to the coordinate systemof the stereotactic apparatus.5.1.2 It is recognized that there is considerable anatomicalvariability in the size and sh
41、ape of the central nervous systemso that the target point that is identified from the atlas or tableis only approximate. Usually, where possible, physiologicalverification may also be obtained. One must distinguish be-tween the anatomical accuracy, which is inexact because of thevariability of brain
42、s, and the mechanical accuracy, which is afunction of the precision of the stereotactic instrument.5.1.3 The requirements set forth herein are concerned onlywith the mechanical accuracy of stereotactic instruments. It isalso recognized that once minimum standards for mechanicalaccuracy have been obt
43、ained, increased mechanical precisionwill not necessarily lead to increased anatomical precision.6. Application6.1 Attachment to the SkullIt is necessary to fix thestereotactic apparatus to the skull firmly in order to maintain anaccurate relationship between the stereotactic apparatus and theskull.
44、 Those stereotactic apparatus which are attached to aplatform or operating table shall provide for the rigid fixationof the skull to the apparatus or to the supporting platform.There shall be no visible movement of the frame of theapparatus in relation to the skull with the application of forcesof m
45、agnitude and direction as would ordinarily be encounteredduring stereotactic surgery. Furthermore, fixation shall besecured enough to maintain mechanical accuracy. Design andconstruction of the apparatus shall be such that forces inciden-tal to screwing its attachment pins into the skull do not dist
46、ortthe system to the extent of compromising its mechanicalaccuracy.6.2 Access for Radiology or Other VisualizationSince thecentral nervous system landmarks are identified roentgeno-graphically or by other means, the apparatus or that part of theapparatus from which movements are made, when properlya
47、pplied to the patient, shall be arranged in such a way thatradiographs can be made in more than one plane or othervisualization obtained. Means shall also be available to repo-sition the X-ray tubes accurately and conveniently. The ster-eotactic apparatus shall be constructed in such a way that nome
48、chanical part interferes with X-ray, computerized tomogra-phy or other necessary visualization of landmarks during thepart of the procedure when radiographs are being made.6.3 Accuracy of the Probe PlacementThe accuracy ofplacement in an anatomical target is dependent on anatomicalvariability which
49、exceeds the mechanical inaccuracies of thestereotactic system. Nevertheless, specifications for mechani-cal precision, to a practical extent, are appropriate to obtainmaximum target accuracy with an electrode or other probe. Ingeneral, the mechanical precision of a stereotactic apparatusshould be sufficient to place a probe at a given point in spaceone half the diameter of the probe. Since most electrodes orprobes are larger than 1.2 mm in diameter, a mechanicalaccuracy of 0.6 mm at the 99 % confidence level would ensurethat a given point is generally includ
