ASTM F1831-97(2006)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:F1831 −97(Reapproved 2006)
Standard Specification for
Cranial Traction Tongs and Halo External Spinal
Immobilization Devices
This standard is issued under the fixed designation F1831; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope of the user of this standard to establish appropriate safety and
health practices and determine the applicability of regulatory
1.1 This specification covers standards a manufacturer shall
limitations prior to use.
meet in the designing, manufacturing, testing, labeling, and
documenting of halo and tong external spinal immobilization
2. Referenced Documents
devices, but it is not to be construed as production methods,
quality control techniques, manufacturer’s lot criteria, or clini-
2.1 IEC Standard:
cal recommendations.
IEC 601-1 Medical Electrical Equipment
1.2 This specification represents the best currently available
test procedures at this time and is a minimum safety and 3. Terminology
performance standard.
3.1 Definitions of Terms Specific to This Standard:
3.1.1 cranial traction tong—a device providing weighted
1.3 This specification covers only those halo and tong
devices intended for use on humans for therapeutic purposes. cervical traction to a patient through invasive attachment to the
skull. This traction instrument is indicated for closed reduction
This specification assumes the user is well-trained in the
procedures and maintenance of halo and tong application and of a cervical spine injury (that is, fracture or dislocation).
has the ability to determine if an abnormality is treatable by
3.1.1.1 adjustable tong—a cranial traction tong that adjusts
these procedures.
for size, pin positioning, or pin pressure.
1.4 This specification describes those devices commonly
3.1.1.2 one-piece tong—a rigid, single-piece, semicircular
known as halo external fixation devices and what is known as
cranial traction tong designed to accommodate a minimum of
cranial traction tongs.
two skull pins for mounting the device to the patients head
below the equator.
1.5 Cranial traction tongs and halo devices are used to
achieve and maintain optimal spinal alignment, in order to
3.1.2 halo device—an external fixator for cervical stabiliza-
enhance fusion and decrease neurological deficit.
tion that fastens by invasive means to a patient’s skull, and
maintains the position of the skull in relation to the thoracic
1.6 Monitoringtheprogressoftreatmentafterapplicationof
area of the patient.
these devices is important, this should be done in accordance
with the manufacturer’s recommendation and guidelines per- 3.1.3 halo ring—the portion of the halo device that fastens
taining to the specific device. by invasive means to a patient’s skull below the head equator.
3.1.3.1 closed loop halo ring—a halo ring incorporating a
1.7 The values stated in both inch-pound and SI units are to
closed loop anywhere in the design for purposes of structural
be regarded separately as the standard. The values given in
integrity when the ring is in use. This type of ring has multiple
parentheses are for information only.
positioningoptionsfortheselectionofpinsitesandismounted
1.8 The following precautionary statement pertains only to
to the head with multiple skull pins.
the test method portions Sections 10-15 of this specification:
3.1.3.2 head equator—the greatest circumference of the
This standard does not purport to address all of the safety
head in the coronal aspect
concerns, if any, associated with its use. It is the responsibility
3.1.3.3 open loop halo ring—a halo ring with a posterior
opening, such that the part does not incorporate a closed loop
1 anywhere in the design for structural integrity. This ring has
This specification is under the jurisdiction of ASTM Committee F04 on
Medical and Surgical Materials and Devices and is the direct responsibility of
Subcommittee F04.31 on Neurosurgical Standards.
Current edition approved March 1, 2006. Published April 2006. Originally
approved in 1997. Last previous edition approved in 1997 as F1831 – 97. DOI: Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
10.1520/F1831-97R06. 4th Floor, New York, NY 10036.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F1831−97 (2006)
multiple position options for the selection of pin sites and is 5.2 Cranial Traction Tongs—Either a rigid single-piece,
mounted to the head with multiple skull pins. semicircular device or an adjustable device. Both designs have
accommodations for at least two skull pins to be mounted to
3.1.4 halo superstructure—a rigid external framework used
the skull. Typically designed to be fitted over the top of the
to maintain positioning of the skull and cervical spine in
head and used for weighted cervical reduction or bed traction,
relation to the thoracic and lumbar spine. Connects the halo
or both, in the supine (bed restricted) patient.
ring to halo vest.
3.1.4.1 halo superstructure adjustment mechanisms— com-
6. Magnetic Resonance Imaging Compatibility
ponents that allow adjustment of angles and distances between
Requirements
ring and uprights or vest and uprights.
6.1 These halo external fixator and cranial traction tong
3.1.4.2 transverse bar—a rigid horizontal component of the
magneticresonanceimaging(MRI)compatibilityrequirements
halo superstructure.
are intended to protect the patient from harm during MRI
3.1.4.3 upright bar—a rigid vertical component of the halo
imaging procedures.
superstructure.
6.2 Manufacturers shall be responsible for testing the MRI
3.1.4.4 vest attachment mechanism—attaches inferiorly to
safety and efficacy of the device.
the halo superstructure and connects to vest shell, maintains
6.2.1 Test Methods—See Sections 13-15.
positioning of the halo superstructure in relation to the vest
shell.
7. Mechanical Integrity
3.1.4.5 vest plate—part of the superstructure attached to the
7.1 Thepurposeofthisrequirementistoensuretheuserand
vest shell to provide a stable mounting point for the vest
the patient that the halo external fixator or cranial traction
attachment mechanisms.
tongs, or both, are capable of withstanding the externally
3.1.5 halo vest—a body-orthosis that serves as a mounting
imposedconditionsnormallyencounteredduringtheusefullife
point for the halo and superstructure.
of the device.
3.1.5.1 C.P.R. access—mechanism in vest or superstructure
7.2 Cranial Traction Tongs Mechanical Integrity:
to allow quick access to patient’s chest for cardiopulmonary
7.2.1 The cranial traction tongs and any of its components
resuscitation (C.P.R.).
must be manufactured from a material that provides suitable
3.1.5.2 vest liner—padding worn inside of halo vest shell
rigid support to the skull pins and any other attached compo-
and against the skin which distributes the pressure of the vest
nents including the traction weights.
shell against the skin.
7.2.2 Cranialtractiontongpinsshallbesufficientlystrongto
resist at least two times the normal maximum static loads that
3.1.5.3 vest shell—rigid portion of body orthosis.
may be encountered during normal wear.
3.1.6 skull pin—a rigid device used to invasively anchor the
7.2.3 The cranial traction tongs and its components shall be
halo ring or cranial traction tongs to the skull at selected
resistant to deformation and sufficiently rigid such that pin
mounting points.
position and pressure on the skull can be maintained at
3.1.6.1 adjustable skull pin—(1) a pin that is force con-
maximum manufacturer’s specified pin pressures.
trolled by a mechanical mechanism, that is, spring-loaded
7.2.4 Adjustable skull pins shall be calibrated with force
pressure pin. (2) a solid threaded pin that maintains pressure
indicators.
and fixation against the skull through application of a cali-
7.2.5 Test Method—See Section 10.
brated torque.
7.3 Halo Skull Pin Mechanical Integrity:
3.1.6.2 fixed skull pin—a pin that is mounted directly to a
7.3.1 Halo skull pins shall be sufficiently strong to resist at
tong structure requiring a drilled skull hole for positioning and
least two times the normal maximum static and dynamic loads
fixation. Pressure is not adjusted directly through the pin.
that may be encountered during normal use.
3.1.7 traction bail (traction hoop)—a device that may be
7.3.2 Test Method—See Section 11.
attached to the halo ring to facilitate the application of
7.4 Halo Ring Mechanical Integrity:
weighted longitudinal traction.
7.4.1 The halo ring shall be manufactured from a material
4. Conformance
that provides suitable rigid support to the attached skull pins
and superstructure.
4.1 Presently, this specification is voluntary and not by law.
7.4.2 The halo ring shall be resistant to deformation and
A manufacturer may label a product as conforming to this
sufficiently rigid such that pin position and pressure on the
specification only if the product indeed meets all the require-
skull can be maintained at maximum manufacturer’s specified
ments of this specification.
pin pressures.
5. Classification 7.4.3 Test Method—See Section 11.
7.5 Halo Superstructure Assemblies Mechanical Integrity:
5.1 Halo External Fixator—Typically a complete system
consisting of the halo ring, skull pins, vest and superstructure. 7.5.1 A new halo external fixator device must be able to
The uniqueness of this system is its ability to provide self- maintain structural integrity under normal physical loading
contained cervical stabilization. when the system is fully assembled.
F1831−97 (2006)
7.5.2 All mechanical components of the superstructure as- skin. These lining materials shall be free of any chemicals or
semblymustmaintainrigidityandfunctionalintegritythrough- toxins, or both, that could cause an allergic response in the
out the useful life of the product. average patient.
7.5.3 Test Method—See Section 12.
8.6.3 The halo vest shall have a vest attachment mechanism
whereby the halo superstructure is suitably attached via the
7.6 Halo Vest Assembly Mechanical Integrity:
appropriate tools or mechanism.
7.6.1 The halo vest assembly must provide a stable platform
8.6.4 The halo vest shall allow rapid and complete access to
for rigid attachment of the superstructure.
the chest in the event of a cardiac emergency to allow access to
7.6.2 The halo vest must provide an adjustable means of
the chest for C.P.R.
rigid fixation to the upper body of the patient.
8.7 Halo Tools Performance Requirements—All halo ad-
8. Performance Requirements
justment tools supplied by the manufacturer shall consistently
perform in the manner to which they were designed throughout
8.1 The purpose of these requirements is to ensure that a
the useful life of the product or as indicated by the manufac-
halo external fixator or cranial tongs shall meet the minimum
turer’s recommendations.
performance requirements as originally designed.The halo and
tongs device requirements should not vary from procedure to
8.8 Cranial Traction Tongs Performance Requirements:
procedure provided they are used and maintained according to
8.8.1 All mechanical fixation components will be manufac-
the manufacturer’s recommendation.
tured out of corrosion resistant materials.
8.2 Halo External Fixator Performance Requirements: 8.8.2 All components shall be manufactured out of materi-
8.2.1 All mechanical fixation components will be manufac- alscapableofprovidingfunctionalintegrityovertheusefullife
of the device.
tured out of corrosion resistant materials.
8.2.2 All components shall be manufactured out of materi- 8.8.3 The manufacturer will be responsible to maintain
alscapableofprovidingfunctionalintegrityovertheusefullife
adequate mechanical test data or equivalent clinical data in
of the device. regard to the suitability of design, useful life and diagnostic
8.2.3 The manufacturer will be responsible to maintain imaging compatibility of the system.
adequate mechanical test data or equivalent clinical data in
8.8.4 The manufacturer will be responsible for supplying
regard to the suitability of design, useful life and diagnostic
materials that are sterilizable by the manufacturer’s recom-
imaging compatibility of the system.
mended sterilization techniques.
8.2.4 The manufacturer will be responsible for supplying
8.8.5 The cranial traction tongs must permit attachment of
materials that are sterilizable by the manufacturer’s recom-
cables and other necessary hardware.
mended sterilization techniques.
8.9 Cranial Traction Tongs Pin Performance Requirements:
8.3 Halo Pin Performance Requirements:
8.9.1 All tong pins must be supplied by the manufacturer
8.3.1 All portions of the skull pin that are in constant
with a method of locking.
physical contact with the patient’s skin shall be manufactured
8.9.2 Any portion of the tong pin that is in direct contact
from biologically compatible material.
with the patient’s skin shall be manufactured from biologically
8.3.2 All halo skull pins shall be supplied with a method for
compatible materials.
locking the pin in place in the halo ring.
8.4 Halo Ring Performance Requirements—The manufac- 9. Disclosures, Labeling, and Documentation
turer will be responsible for providing a ring assembly that
9.1 These requirements are intended to ensure a manufac-
allows for the following:
turer’s written dissemination of all necessary information that
8.4.1 The halo ring shall be able to easily and rigidly attach
allow a user to determine properly a halo external fixator or
to the superstructure.
cranial traction tongs (and all of their related accessories)
8.4.2 The halo ring shall be able to easily accept a minimum
function, application and limitation. These disclosures, label-
of four halo skull pins.
ing and documentation requirements also ensure clear identi-
fication of the product and make available all pertinent data a
8.5 Halo Superstructure Assembly Performance Require-
user may require. A manufacturer may label his product as
ments:
conformingtothisstandardonlyiftheproductfulfillsallofthe
8.5.1 The halo vest and superstructure assemblies shall be
requirements listed in this specification.
able to be easily attached and detached from the halo ring with
the appropriate tools.
9.2 Disclosures—A manufacturer shall disclose each speci-
fication listed where applicable.
8.6 Halo Vest Performance Requirements:
9.2.1 Single Patient Use Statement—Amanufacturer of halo
8.6.1 The vest material shall be trimmable and moldable
with the appropriate tools to allow the medical personnel to exte
...