Journal of Ultrasound in MedicineEarly View Practice ParameterFree Access The AIUM Practice Parameter for the Performance of an Ultrasound Examination of the Neonatal and Infant Spine First published: 18 November 2021 https://doi.org/10.1002/jum.15875AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Introduction The American Institute of Ultrasound in Medicine (AIUM) is a multidisciplinary association dedicated to advancing the safe and effective use of ultrasound in medicine through professional and public education, research, development of clinical practice parameters, and accreditation of practices performing ultrasound examinations. The AIUM Practice Parameter for the Performance of an Ultrasound Examination of the Neonatal and Infant Spine was revised by the AIUM in collaboration with other organizations whose members use ultrasound for performing this examination (see “Acknowledgments”). Recommendations for personnel requirements, the request for the examination, documentation, quality assurance, and safety may vary among the organizations and may be addressed by each separately. This practice parameter is intended to provide the medical ultrasound community with recommendations for the performance and recording of high-quality ultrasound examinations. The parameters reflect what the AIUM considers the appropriate criteria for this type of ultrasound examination but is not intended to establish a legal standard of care. Examinations performed in this specialty area are expected to follow the parameter with the recognition that deviations may occur depending on the clinical situation. Indications The indications for ultrasonography of the neonatal/infant spinal canal and its contents include, but are not limited to1-13: Lumbosacral stigmata known to be associated with spinal dysraphism and tethered spinal cord, including: Midline or paramedian masses Midline skin discolorations Skin tags Hair tufts Hemangiomas Atypical sacral dimples (high risk; see below) The spectrum of caudal regression syndrome, including patients with sacral agenesis or anorectal malformations such as Currarino Triad, VACTERL association, Cloaca, and OEIS complex Evaluation of suspected spinal cord abnormalities such as cord tethering, diastematomyelia, hydromyelia, or syringomyelia Detection of acquired abnormalities and complications such as: Hematoma following injury Infection or hemorrhage secondary to prior instrumentation, such as lumbar puncture Posttraumatic leakage of cerebrospinal fluid (CSF) Misplacement of devices and lines Visualization of blood products within the spinal canal in patients with intracranial hemorrhage Guidance for lumbar puncture11, 12 Postoperative assessment for recurrence of cord tethering14 Evaluation for congenital spine tumors, for example, sacrococcygeal teratoma Please note that there are some indications for ultrasonography of the spine and spinal canal in children outside the neonatal or infant period. The technique for these studies is beyond the scope of this practice parameter but is described in the literature. These indications include, but are not limited to, intraoperative guidance for tumor resection, decompression of Chiari I malformation, and catheter placement for neuraxial analgesia,15, 16 neurostimulator device placement and monitoring its positioning, and assessment of lengthening of magnetically controlled growing spinal rods.17 Sacral dimples associated with a high risk of occult spinal dysraphism include those in which the base of the dimple is not seen, are located >2.5 cm above the anus, or are seen in combination with other cutaneous abnormalities.3 The examination has a low diagnostic yield in infants with simple, low-lying coccygeal dimples; such patients typically have normal spinal contents.3, 7, 13, 15 Ultrasound is not considered essential in the workup of simple sacral dimples. Contraindications Preoperative examination of an open spinal dysraphic defect. However, in such cases, the closed portion of the spinal canal away from the open defect can be examined for other suspected abnormalities, such as syrinx or diastematomyelia. These latter abnormalities should be identified preoperatively. Examination of the contents of a closed neural tube defect, if the skin overlying the defect is thin or no longer intact Qualifications and Responsibilities of Personnel Physicians interpreting or performing this type of ultrasound examination should meet the specified AIUM training guidelines in accordance with AIUM accreditation policies. Sonographers performing the ultrasound examination should be appropriately credentialed in the specialty area in accordance with AIUM accreditation policies. Physicians not personally performing the examination must provide supervision, as defined by the Centers for Medicare and Medicaid Services Code of Federal Regulations 42 CFR §410.32. Request for the Examination The written or electronic request for an ultrasound examination must originate from a physician or other appropriately licensed health care provider or under the provider's direction. The clinical information provided should allow for the performance and interpretation of the appropriate ultrasound examination and should be consistent with relevant legal and local health care facility requirements. Specifications of the Examination The examination is usually performed with the patient lying in the prone position, although the study can also be done with the patient lying on their side. When necessary, upright or prone reversed Trendelenburg positioning with resultant CSF distention of the lower thecal sac may permit better delineation of the cauda equina. A small bolster may be placed under the lower abdomen or pelvis to mildly flex the back, which may improve imaging. The knees may be flexed to the abdomen to allow adequate separation of the spinous processes and visualization of the spinal canal contents. Avoid overzealous and excessive flexing that could impede respiration.18 An infant who has recently been fed will generally lie quietly during the examination. If preprocedural feeding is not possible, a pacifier dipped in glucose solution can be helpful in keeping an infant still, thereby optimizing the examination. The infant may be also positioned in the caregiver's lap, which may have a calming effect, decreasing motion. Positioning the infant semierect also allows for accumulation of CSF in the lower thecal sac, which widens the interlaminar spaces and creates a better acoustic window. Furthermore, this gravitational CSF distention may increase detection of any existing lumbosacral meningoceles.17 It is important to note that infants, particularly if not full-term, have difficulty maintaining normal body temperature. The baby should be kept warm enough to maintain normal body temperature during the procedure, and the coupling agent should be warmed. The spinal cord should be assessed in longitudinal and transverse planes, with right and left labeled on transverse images. Longitudinal images are ideally obtained in the midline sagittal plane, although in larger or older babies (with greater spine ossification), it may be necessary to obtain images in a slightly off-midline parasagittal plane that is parallel to the spinous processes. Studies are typically limited to the lumbosacral and lower thoracic region as in patients being evaluated for a sacrococcygeal dimple and tethered cord, or when searching for the presence of hematoma after an unsuccessful or traumatic spinal tap. However, the entire spinal canal, from the craniocervical junction to the coccyx, may be included in the examination. Normal cord morphology and the level of termination of the conus medullaris should be assessed and documented, which requires accurate identification of vertebral body level. The conus normally lies at or above the L2 to L3 disc space.9, 19-22 A normal conus located as low as the mid-L3 level may be identified, especially in preterm infants22; this position may be considered the lower limits of normal and is usually without clinical consequence.23 However, in a preterm infant with a conus that terminates in the region of the L3 midvertebral body, a follow-up ultrasound can be obtained once the infant attains a corrected age between 40 weeks gestation and 4 months of age to document a rise in conus level.8 The morphology of the conus should be documented as well as any deviation from normal, such as blunting of the tip. Vertebral body level of the end of the spinal cord can be determined in a number of ways.24, 25 These include: Assessment of the normal lumbosacral curvature to locate the lumbosacral junction and thus the location of L5. The vertebral level of the conus medullaris is then determined by counting cephalad from L5. Lumbar vertebral bodies typically lie in a horizontal plane in a prone infant, whereas the sacral vertebral bodies lie at an angle similar to what is seen on lateral radiographs of the lumbosacral spine. This counting method tends to be more reproducible than the other methods described below. Extended field-of-view (panoramic) imaging can often aid in identification of a longer segment of the spine and facilitate identification of the vertebral level, particularly the L5-S1 level. Lumbar spine flexion-extension maneuvers might also allow easier identification of the lumbosacral junction. The first coccygeal segment has variable ossification at birth. If ossified, it can be distinguished by its rounder or more triangular shape compared with the square or rectangular shape of the sacral bodies. Counting cephalad from the fifth sacral ossification center can help determine the vertebral level of the conus. The thecal sac usually ends at S2.26 This level can then be used to count cephalad to determine the location of the conus. The last rib-bearing vertebra can be presumed to be T12, and the lumbar level of the conus can then be determined, although this is less reliable because of the variability in the number of ribs. When the level of the conus cannot be definitively assessed as normal or abnormal, correlation with previous plain films, if available, is helpful. A radiopaque marker can be placed on the skin at the level of the conus determined by sonographic guidance, followed by a correlative anteroposterior spine radiograph. In addition to the level and location of the cord, motion of the nerve roots is another important parameter in assessment for cord tethering. The cord is normally positioned dependently or centrally within the spinal canal, and any deviation from normal (eg, apposition to the dorsal aspect of the spinal canal) should be documented. Transverse images are extremely helpful to demonstrate a dependent position of the cord. Cine images should be recorded and archived as an aid in demonstrating anatomy and particularly in showing movement of the distal cord and nerve roots in conjunction with normal pulsations of the spinal CSF. The normal nerve roots typically oscillate freely with cardiac and respiratory motion, layer dependently with variable patient positioning, and are not adherent to each other. Cine images can also document changes that occur with head flexion and extension. M-mode ultrasound can also be helpful in documenting motion of the cord and nerve roots. In newborns, diminished or absent motion of the conus and cauda equina due to decreased subarachnoid fluid related to the normal dehydration status has been reported. In these instances, follow-up spine ultrasound may be warranted.27 Areas of abnormal fluid accumulation within the spinal cord and spinal canal should be documented with their level identified, such as hydromyelia or syringomyelia; anterior, lateral, or posterior meningoceles or pseudomeningoceles; and arachnoid cysts. Transverse images are essential to identify and document diastematomyelia. Off-center scanning may avoid the refraction artifact that creates an apparent lateral cord duplication, or ghost image that resembles diastematomyelia.28-30 The subarachnoid space is normally anechoic in appearance, interrupted by normal hyperechoic linear nerve roots and dentate ligaments. The subarachnoid space, dura, and epidural space should be evaluated for abnormalities such as hematoma, lipoma, or other masses. In addition to the termination of the conus, the termination of the thecal sac, typically located at S2, should be documented.26 The filum terminale and its thickness should be noted; the filum is normally <2 mm thick,31 although recent studies have suggested a lower cutoff value of 1.1 mm.32 Increased echogenicity and thickening of the filum may indicate a fatty filum. Upright positioning can be used for image guidance of lumbar puncture or to demonstrate meningoceles or pseudomeningoceles. Anterior meningoceles or presacral masses can also be scanned from an anterior position, usually through a fluid-filled bladder. The vertebral bodies and posterior elements can be evaluated for deformities. Open posterior elements in skin-covered dysraphic defects can be documented on transverse views. Tracts extending from the skin surface should be assessed for connection to the spinal canal. A standoff pad or a thick layer of coupling gel may be used, if needed, to evaluate the superficial soft tissues and skin line for the presence of a tract. Documentation Accurate and complete documentation is essential for high-quality patient care. Written reports and ultrasound images/video clips that contain diagnostic information should be obtained and archived, with recommendations for follow-up studies if clinically applicable, in accordance with the AIUM Practice Parameter for Documentation of an Ultrasound Examination. The initials of the operator should be accessible on the images or electronically in the electronic medical record (eg, PACS or radiology information software). Equipment Specification Equipment performance monitoring should be in accordance with the AIUM Routine Quality Assurance of Clinical Ultrasound Equipment, Version 2.0.33 Ultrasound of the infant spine should be performed with real-time scanners using high-frequency linear array transducers, typically ranging from 9 to 12 MHz or higher in neonates.34 In larger babies, it may be necessary to utilize a lower-frequency probe ranging from 5 to 9 MHz. A curvilinear probe ranging from 3 to 9 MHz may be needed if a larger field of view is desired or the acoustic access is limited, as in older infants. Panoramic views of the entire spinal canal are very helpful in providing an overview of the anatomy by displaying a more global image of the relationship of the spinal cord with the vertebral column and determining the level of the conus medullaris. The use of a split-screen or dual-function technique is similarly useful for obtaining a longer longitudinal image of the cord and spinal column. Images of the craniocervical junction can be obtained with a small vector or curved transducer to accommodate the curvature of the cervical spine. Clinical protocols should be reviewed to optimize image quality while reducing possible risks due to thermal and mechanical effects. Quality and Safety Policies and procedures related to quality assurance and improvement, safety, infection control, and equipment performance monitoring should be developed and implemented in accordance with the AIUM Standards and Guidelines for the Accreditation of Ultrasound Practices. ALARA (As Low as Reasonably Achievable) Principle The potential benefits and risks of each examination should be considered. The ALARA principle should be observed for factors that affect the acoustical output and by considering transducer dwell time and total scanning time. Further details on ALARA may be found in the current AIUM publication Medical Ultrasound Safety. Infection Control Transducer preparation, cleaning, and disinfection should follow manufacturer recommendations and be consistent with the AIUM Guidelines for Cleaning and Preparing External- and Internal-Use Ultrasound Transducers Between Patients, Safe Handling, and Use of Ultrasound Coupling Gel. Equipment Performance Monitoring Monitoring protocols for equipment performance should be developed and implemented in accordance with the AIUM Standards and Guidelines for the Accreditation of Ultrasound Practice. Acknowledgments This parameter was developed by the AIUM in collaboration with the American College of Radiology (ACR), the Society for Pediatric Radiology (SPR), and the Society of Radiologists in Ultrasound (SRU). We are indebted to the many volunteers who contributed their time, knowledge, and energy to developing this document. Collaborative Subcommittees AIUM Susan J. Back, MD Nadia F. Mahmood, MD Mariana Meyers, MD, FAIUM ACR Jane Sun Kim, MD, Co-Chair Erica Poletto, MD, Co-Chair Harriet J. Paltiel, MD, FAIUM Henrietta K. Rosenberg, MD, FACR Judy H. Squires, MD SPR Paul Clark, DO Harris L. Cohen, MD, FACR, FAIUM, FSRU Monica Epelman, MD SRU Lynn A. Fordham, MD, FACR, FAIUM, FAAWR Comment Reconciliation Committee Richard Gunderman, MD, FACR, Chair Timothy Crummy, MD, FACR, Co-Chair Susan J. Back, MD Richard A. Barth, MD, FACR Paul Clark, DO Harris L. Cohen, MD, FACR, FAIUM, FSRU Richard Duszak Jr., MD, FACR Samuel A. Einstein, PhD Monica Epelman, MD Lynn A. Fordham, MD, FACR, FAIUM, FAAWR Lauren P. Golding, MD Jane Sun Kim, MD Amy Kotsenas, MD, FACR David B. Larson, MD, MBA Paul A. Larson, MD, FACR Terry L. Levin, MD, FACR Nadia F. Mahmood, MD Mariana Meyers, MD, FAIUM Mary S. Newell, MD, FACR Harriet J. Paltiel, MD, FAIUM Erica Poletto, MD Margarita Revzin, MD, FAIUM Henrietta K. Rosenberg, MD, FACR Michael Ian Rothman, MD, FACR Ramon Sanchez-Jacob, MD Sheila Sheth, MD, FACR James Shwayder, MD, FAIUM Cicero Silva, MD Judy H. Squires, MD Richard B. Towbin, MD, FACR AIUM Clinical Standards Committee James M. Shwayder, MD, JD, FAIUM, chair Rachel Bo-ming Liu, MD, FAIUM, vice chair Bryann Bromley, MD, FAIUM Nirvikar Dahiya, MD, FAIUM Rob Goodman, MBBCh, MBA, BMSc Margarita Revzin, MD, FAIUM Jean Spitz, MPH, CAE, RDMS, FAIUM John Stephen Pellerito, MD, FAIUM Original copyright 2007; Revised 2021, 2016, 2011; Renamed 2015 References 1Guggisberg D, Hadj-Rabia S, Viney C, et al. Skin markers of occult spinal dysraphism in children: a review of 54 cases. Arch Dermatol 2004; 140: 1109– 1115. CrossrefPubMedWeb of Science®Google Scholar 2Izci Y, Gonul M, Gonul E. The diagnostic value of skin lesions in split cord malformations. J Clin Neurosci 2007; 14: 860– 863. CrossrefPubMedWeb of Science®Google Scholar 3Kriss VM, Desai NS. 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