A great deal of information has been forwarded by the chiropractic profession as to the clinical utility of VF in the documentation of intersegmental dysfunction. The term "subluxation" is frequently used, but rarely defined in these papers. Bell,[2] in a topic review purports that VF is an established reliable method of evaluating spinal mechanics. He implies that VF is useful in the evaluation of joint motion. While this cannot be disputed, drawing conclusions about the normality or abnormality of that motion is unreliable, unvalidated, and has not been tested as far as clinical correlation. He criticizes the ACA for their position on VF[19], and states "The question is not whether the procedure is helpful in the diagnosis of motion abnormalities; that has already been established." He further states that the issues which still need addressing are: "What constitutes the best equipment? How do we interpret what we see? How can the images be measured? When do we use VF to evaluate patients?" It would appear that when, how, why and what equipment to use would be central issues to address before unleashing this modality on the public.
A variety of others have attempted to justify the use of VF in clinical practice. These take the form of literature reviews and case reports extolling the benefits of this procedure. Once again, the issues of normal vs. abnormal, reliability, validity, clinical correlation and therapeutic significance are either not addressed, or the terminology which they report success with demonstrating (i.e. instability, subluxation) are not defined, leaving the reader to form his or her own opinions as to what they meant.[21,22,23,24,25,26]
The issue of unique diagnostic utility has been addressed in the VF literature. Bailey performed a study in which he evaluated 40 cervical spines by comparing VF to flexion/extension stress films. The variables assessed in their study were; excessive motion, hypermobility and/or instability. None of these terms was defined for the purpose of the study. Using three radiologists, he concluded that VF was more sensitive and specific than plain films. Unfortunately, he stated that for the purposes of the study, VF was considered the gold standard. This means that no false positives could be calculated from the data for VF. Further, there has been no literature ever published which documents the reliability or validity of VF in the assessment of their undefined variables.[27]
Antos, et al., evaluated the inter-examiner reliability of videofluoroscopy in the detection of cervical "fixations". They defined fixation as those segments "moving fifty percent or less of the distance between spinolaminar junctions in neutral position when flexed forward". Their methods involved stopping the videofluoro tape at neutral and full flexion positions so that mensuration could be made from the screen. It would appear that their study was more an assessment of inter-rater reliability of measuring values from a TV screen than assessing inter-rater reliability of VF observations. They stated that their definition of fixation was not in common clinical use, and might not be clinically useful. The examiners achieved 94% total agreement, however, in the discussion they state that the agreement may have been overestimated due to the fact that both examiners measurements were obtained at the same "freeze frame" image on the TV, one immediately after the other.[21]
Jones stated in his assessment of 45 cervical spines that VF was necessary to demonstrate an abnormality in 17 of them. They still considered VF necessary when major diagnoses were apparent on plain film, but certain aspects relating to the timing of the motion were apparent only on VF. Only two cases of the 45 demonstrated abnormality which was not seen on the flexion/extension views. They concluded that the "total degree of instability or the combination of instability and restricted motion are no better depicted by cineradiography than by plain roentgenogram if adequate flexion/extension views are obtained".[28]
From the literature presented, it is clear that the most reliable evidence speaks strongly against videofluoroscopy as a technique for clinical use at this time. There is limited evidence that certain indications for VF exist, but any attempt to quantify the findings therein remains without foundation. There is early evidence that high resolution digital fluoroscopy may prove a reliable method of measuring motion in the spine,[8,9,11,12,29,30] but it's developers feel that the cost and potential for error render it a modality which should remain in the laboratory for the time being.[11] Assuming eventual demonstration of reliability, the questions of clinical utility, diagnostic significance and therapeutic significance of this modality will require attention.
2. Bell GD. Skeletal applications of videofluoroscopy. J Manipulative Physiol Ther 1990; 13:396-405.
3. Moretzsohn De Castro J. Fundamental principles in the application of cineroentgenography as an auxiliary method to roentgen diagnosis. Am J Roentgen 1947; 57:103-14.
4. Fielding JW. Cineradiography of the normal cervical spine. NY State J Med 1956; (Oct):294-6.
5. National Council on Radiation Protection. Basic radiation protection criteria. NCRP Report No.39, 1974:1-117.
6. National Council on Radiation Protection. Medical x-ray and gamma-ray protection for energies up to 10 MeV: equipment design and use. NCRP Report No.33, 1975:1-66.
7. National Council on Radiation Protection. Recommendations on limits for ionizing radiation exposure. NCRP Report No.91, 1987.
8. Breen AC, Allen R, Morris A. Spine kinematics: a digital videofluoroscopic technique. J Biomed Eng 1989; 11:224-8.
9. Breen A, Allen R, Morris A. An image processing method for spine kinematics -- preliminary studies. Clin Biomech 1988; 3:5-10.
10. Cholewicki J, McGill SM, Wells RP, Vernon H. Method for measuring vertebral kinematics: videofluoroscopy. Clin Biomech 1991; 6:73-8.
11. Breen A. The digital videofluoroscopic assessment of spine kinematics. In: proceedings of the International Conference on Spinal Manipulation. Arlington, Virginia: Foundation for Chiropractic Education and Research, 1990:86-92.
12. Breen A. The reliability of palpation and other diagnostic methods. World Chiropractic Congress, Proceedings of the Scientific Symposium, 4-5 May 1991:7.1-7.11.
13. Schram S, Hosek R. Error limitations in x-ray kinematics of the human spine. J Manipulative Physiol There 1982; 5:5-10.
14. White AJ, Panjabi MM. The basic kinematics of the human spine: a review of past and current knowledge. Spine 1978; 3:12-29.
15. Kottke FJ, Lester RG. Use of cinefluoroscopy for evaluation of normal and abnormal motion in the neck. Arch Phys Med Rehabil 1958; (Apr):228-31.
16. Dimnet J, Pasquet A, Krag MH, Panjabi MM. Cervical spine motion in the sagittal plane: kinematic and geometric parameters. J Biomech 1982; 15:959-69.
17. Taylor M, Skippings R. Paradoxical motion of atlas in flexion: a fluoroscopic study of chiropractic patients. Eur J Chiropr 1987; 35:116-34.
18. Quebec Task Force on Spinal Disorders. Scientific approach to the assessment and management of activity related to spinal disorders: a monograph for clinicians. Spine 1987; 12(S-7):S3-9.
19. Pammer JC. Videofluoroscopy position statement approved. ACA J Chiropr 1989; 26:46.
20. Howe JW. Radiological investigation of spinal biomechanics. J Can Chiropr Assoc 1976(Dec):16-21.
21. Antos JC, Robinson GK, Keating JC, Jacobs GE. Inter-rater reliability of fluoroscopic detection of fixation in the mid-cervical spine. Chiropr Tech 1990; 2:53-5.
22. Leung ST. The value of cineradiographic motion studies in diagnosis of the cervical spine. Bull Eur Chiropr Union 1977; 25:28-43.
23. Robinson GK, Lantz C. Dynamic spinal visualization: guidelines for the use of videofluoroscopy in chiropractic. ICA Int Rev Chiropr 1989; (Summer):24-8.
24. Robinson GK, Lantz C. Videofluoroscopy in chiropractic management of cervical syndromes. J Chiropr Res Clin Invest 1991; 6:93-7.
25. Shippel AH, Robinson GK. Radiological and magnetic resonance imaging of cervical spine instability: a case report. J Manipulative Physiol There 1987; 10:316-22.
26. Tasharski CC, Heinze WJ, Pugh JL. Dynamic atlanto-axial aberration: a case study and cinefluorographic approach to diagnosis. J Manipulative Physiol Ther 1981; 4:65-8.
27. Bailey DN. Plain film vs. Videofluoroscopy comparison of clinical value in the cervical spine: a retrospective study. ACA J Chiropr 1991; 28(7):59-62.
28. Jones MD. Cineradiographic studies of abnormalities of the higher cervical spine. Arch Surg 1967; 94:206-13.
29. Breen A, Allen R, Morris A. A digital videofluoroscopic technique for spine kinematics. J Mech Technol 1989; 13:109-113.
30. Humphreys K, Breen A, Saxton D. Incremental lumbar spine motion in the coronal plane: an observer variation study using digital videofluoroscopy. Eur J Chiropr 1990; 38:56-62.