Biomedical subjects

K F Spratt

Publications and source records attributed to K F Spratt.

43 records · Page 3Linked to original sources

PubMed1990

1990 Volvo Award in clinical sciences. The consistency and accuracy of roentgenograms for measuring sagittal translation in the lumbar vertebral motion segment. An experimental model.

An experimental model of the L4-L5 lumbar motion segment was developed that allowed precise manipulation of sagittal translation, rotation of L5 relative to L4, tilt of L4 on L5, and control of roentgenogram quality (image clarity) by placing a water bath between the tube and the vertebral body. A series of experiments were designed to systematically assess the consistency and accuracy of sagittal translation measurements from roentgenograms of varying quality, using different measurement protocols and various rater combinations on models with varying degrees of concomitant motions (rotations and tilts). Study 1 assessed the effects of roentgenogram quality, raters, and seven measurement methods on the consistency and accuracy of evaluating translations in the sagittal plane. Results indicated very high reliabilities across roentgenogram quality, raters, and measurement. As expected, high-quality roentgenograms were more accurately evaluated than lower-quality roentgenograms. However, closer inspection of the consequences of errors in measured translations indicated surprisingly high false-positive and false-negative rates, with significant differences observed between measurement methods. Study 2 assessed the effects of concomitant motions and measurement methods on the consistency and accuracy of evaluations. Within-rater consistency and accuracy indices were remarkably high and similar across measurement methods and degrees of concomitant motions. However, important differences in the false-positive and false-negative rates were again observed. Method 2, described by Morgan and King, demonstrated the overall best performance and the least interference due to concomitant motions. Study 3 assessed the effects of raters and measurement methods on the consistency of measuring translation in clinical roentgenograms, where concomitant motion factors may be present, but not explicitly considered. Results indicated substantially lower within- and between-rater consistency estimates relative to consistencies obtained from the model, although these magnitudes were similar to those reported by others evaluating clinical roentgenograms. The implications of lower consistency estimates relative to increased false-positive and false-negative rates must be more closely examined. These studies present evidence suggesting that high consistency and accuracy indices do not ensure acceptable false-positive and false-negative rates and, thus, provide empirical evidence supporting the view that using roentgenograms as a basis for diagnosing instability often can lead to errors in classification. This is less so when observed translations are relatively large (+/- 5+ mm) on roentgenograms that are relatively clear, with little obliquity, and when concomitant motions are minimal.(ABSTRACT TRUNCATED AT 400 WORDS)

Awards and Prizes↗

PubMed1990

Lumbar discography in normal subjects. A controlled, prospective study.

Major advances in the techniques of discography since 1968, in conjunction with major strides in the evaluation of pain in recent years, prompted a study in which Holt's work on the specificity of discography was replicated and extended. For the present study, seven patients who had low-back pain and ten volunteers who had been carefully screened, with a questionnaire and a physical examination, to ensure that they had no history of problems with the back, had an injection at three levels, and all sessions were videotaped. After each injection, the participant was interviewed about the pattern and intensity of the pain, and then the discs were imaged with computed tomography. Five raters, who were blind to the condition of the participant, graded each disc as normal or abnormal on the basis of findings on magnetic resonance images that had been made before the injection and computed tomography (discography) were done. There was only one disagreement between the ratings that were made on the basis of the magnetic resonance images and those that were made on the basis of the discograms. Each participant's pain-related response was evaluated independently by two raters who viewed the videotapes of the discography. Inter-rater reliability was 0.99, 0.93, and 0.88 for the evaluation of intensity of the pain, pain-related behavior, and similarity of the pain to pain that the subject had had before the injection. In the asymptomatic individuals, the discogram was interpreted as abnormal for 17 per cent (five) of the thirty discs and for five of the ten subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1988

Spinal pedicle fixation: reliability and validity of roentgenogram-based assessment and surgical factors on successful screw placement.

The increased popularity of pedicle fixation prompted research to address two issues: the reliability and validity of roentgenograms as a technique for evaluating the success of pedicle fixation, and the effects of surgical factors on successful fixation. Thus, does approach--the point and angle of screw insertion, surgeon experience, practice, level of the spine involved, and screw size--effect success of pedicle fixation? Eight fresh thoracolumbar spines were harvested and cleaned of all soft tissues. Two surgeons, one more experienced in pedicle fixation than the other, used two pedicle fixation approaches (Weinstein and Roy-Camille) on both the left and right sides at levels T11-S1 of each specimen. All screws were placed under anteroposterior (AP) and lateral c-arm control. For specimens 1 to 3, 5.5 mm screws were used at T11-L1, and 7.0 mm screws at L2-S1. Unacceptable failure rates at L2 and L3 for the first three specimens resulted in a change of instrumentation for the remaining specimens, with 5.5 mm screws used at T11-L3 and 7.0 mm screws at L4-S1. When surgeons completed the fixations for a specimen, AP and lateral roentgenograms were taken and both surgeons independently evaluated the films to assess the success of each fixation. Failure was defined as evidence of any cortical perforation on any side of the pedicle in or outside of the spinal canal. After completing the roentgenogram evaluation, the specimen was transected in the midline, and the success of each pedicle fixation was evaluated by visual/tactile inspection. There were no disagreements between surgeons on the visual/tactile evaluations of the specimens.(ABSTRACT TRUNCATED AT 250 WORDS)

Bone Screws↗

PubMed1987

Long-term follow-up of lower lumbar fusion patients.

To determine the long-term effects of lower lumbar fusion, 94 subjects were catalogued from medical records. They had a lumbar arthrodesis at the third lumbar level or below and their operations were performed before 1964. Twenty-four were not located and 8 were deceased. Sixty-two subjects (72% of available sample) completed a telephone interview; 52 subjects completed a comprehensive low back questionnaire; and 33 subjects returned for physical examination, flexion-extension lateral lumbar spine films, and a limited computerized axial tomographic (CAT) scan. In general, the subjects who returned for complete evaluation were representative of the larger sample. Forty of 62 patients were men. Ages ranged from 41 to 83 years; the median age was 66 years, 6 months. Follow-up ranged from 21 to 52 years; the median follow-up was 33 years. Forty-four percent (27/61) were currently experiencing low-back pain, 57% (35/61) had back pain in the last year. Fifty-three percent (33/62) were using medication. Fifteen percent (9/62) had undergone repeat lumbar surgery, however, only 5% (3/62) required surgery as a late sequela (more than 10 years postoperatively). Forty-two percent (14/33) had lumbar spinal stenosis, but only 15% (5/33) had dural tube measurements less than 100 mm2. Segmental instability above the fusion was present in 45% (15/33). There was a significant correlation between segmental instability and lumbar spinal stenosis (r = .57, P less than .01). Neither radiographic condition correlated with symptoms, however.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1986

Lumbar disc herniation. A comparison of the results of chemonucleolysis and open discectomy after ten years.

Using data obtained by questionnaire in a retrospective review of patients with low-back and sciatic pain (eighty-five treated by injection of chymopapain and seventy-one, by open discectomy), the results at one and ten years after treatment were analyzed. For this analysis we used six measures of pain relief, six measures of the patients' course during the ten-year period since primary treatment, and four measures of the patients' history of employment or work since initial treatment. Validity studies demonstrated that the pain-outcome measures reflected the patients' condition adequately and that all six measures were significantly related to each other (Pearson's r, p less than 0.003). The chymopapain and discectomy groups were not distinguishable on the basis of the pain-outcome measures. However, body mass was directly related to the presence of pain ten years after discectomy but not after injection of chymopapain. Analysis of the progress measures (indicators of the course of the patients' pain during the ten-year period) showed that the rates of reoperation in the two treatment groups did not differ significantly, but the discectomy patients tended to have had a higher rate of reoperation at both one and ten years after initial treatment. These measures did not show unequivocal superiority of one treatment compared with the other. Using the work measures (assessments of the patients' history of employment since initial treatment), it was found that in both treatment groups the patients who returned to work six to twelve weeks after treatment despite persistent symptoms had significantly more pain at ten years (p less than 0.04). Also, the patients who returned to work less than six weeks after treatment, while still symptomatic, showed a similar trend. On the other hand, among the patients who were still symptomatic at twelve weeks, it made no difference in the final results whether they returned to work at twelve weeks or thereafter. These findings support the notion that after either discectomy or chemonucleolysis, patients should return to work only after complete symptomatic recovery or a minimum convalescence of twelve weeks.

Adult↗

PubMed1983

The impact of patients with nonorganic physical findings on a controlled trial of transcutaneous electrical nerve stimulation and electroacupuncture.

Fifty-four patients treated in a three-week in-patient rehabilitation program were randomly assigned to and accepted treatment with electroacupuncture (n = 17), TENS (low-intensity transcutaneous nerve stimulation, n = 18) and TENS-dead battery (placebo, n = 18). Outcome measures included estimates of pain (on a visual analogue scale) and disability by both physician and patient as well as physical measures of spine function. Two groups were constructed based on the absence of nonorganic physical findings (Valid group, n = 30) and the presence of two or more nonorganic physical findings out of a possible four (Invalid group, n = 10). Multivariate and univariate analyses of covariance were utilized to determine effects of treatment (acupuncture, TENS, placebo) and the effects of over-reporting (presence of excessive nonorganic physical findings). Statistically significant findings demonstrated that the acupuncture group enjoyed more relief of peak pain and more relief of pain on an average day at the three-month return assessment. Additionally, the acupuncture group demonstrated greater improvement in extension trunk strength at the discharge assessment. The Invalid group were found to have a contaminating effect on the acupuncture results. Analysis also demonstrated associations between nonorganic physical findings and both personality traits ("Conversion V" profile on MMPI) and retention of an attorney. Researchers conducting clinical trials in chronic low-back pain patients should control for contamination by the presence of over-reporters.

Acupuncture Therapy↗

PubMedDate not supplied

Reduction of the gastrointestinal side effects of metrizamide myelography with oral dexamethasone.

A prospective, double-blind study was undertaken to assess the effectiveness of oral dexamethasone premedication in reducing a variety of side effects associated with metrizamide myelography. We also examined the relationship between side effects and needle size, total metrizamide dose, radiographic findings, and personality. Patients were randomly assigned to either a placebo group (44 patients) or a dexamethasone group (38 patients). All patients completed a 24-item symptom checklist before and 24 hr after lumbar myelography. In addition, all patients completed the Minnesota Multiphasic Personality Inventory prior to myelography. Analysis of variance demonstrated a statistically significant decrease in the frequency of gastrointestinal side effects (loss of appetite, nausea, vomiting) in the dexamethasone group. There were no significant differences between the two groups for the other 21 symptoms examined. We concluded that premedication with oral dexamethasone significantly reduces the gastrointestinal side effects associated with metrizamide myelography. This reduction was especially important in older patients.

Administration, Oral↗