Biomedical subjects
Publications and source records attributed to R D Guyer.
Guidelines for radiographs of the lumbar spine are established. In general, radiographs are not believed to be necessary for a first episode of low back pain present for less than 7 weeks. Exceptions to this include various medical or physical findings, which are listed. In general, anteroposterior and lateral views only should be done initially. Indications for other views are discussed.
With the current emphasis on cost containment, it is important to order the single best diagnostic test when clinical uncertainties must be resolved. Magnetic resonance imaging is currently the optimal imaging modality to provide the maximum amount of information when evaluating patients with suspected spinal disorders. A comprehensive magnetic resonance imaging study is needed along with a subspecialty interpretation to provide the greatest amount of useful clinical information.
STUDY DESIGN: Fifteen patients meeting rigid study entrance criteria for undergoing a combined anteroposterior L4-S1 spinal fusion as a first time operation were included in the study. Bone mineral density changes at adjacent segments (L3 and L2) were assessed by scanning patients in the anteroposterior and lateral projections before surgery and 3 and 6 months after surgery. OBJECTIVES: To prospectively evaluate changes in bone mineral density at adjacent segments after lumbar spinal fusion and postoperative bracing. SUMMARY OF BACKGROUND DATA: The majority of studies investigating changes in bone mineral density after spinal fusion have been performed in canines. Although such work has provided valuable insight, its application to humans is questionable because the loading mechanics are so different. METHODS: Bone mineral density was assessed noninvasively by dual energy x-ray absorptiometry in the lateral and anteroposterior projections. Data were analyzed with special edge detection software. RESULTS: In the lateral projection at L3, one level above the fusion, the preoperative bone mineral density was 0.91 +/- 0.24 (mean +/- standard deviation in g/cm2). This decreased significantly at 3 months to 0.82 +/- 0.24 and remained reduced at 6 months (0.80 +/- 0.21). This reflected a loss of primarily trabecular bone. In the anteroposterior projection at L2, there was a significant loss at 3- and 6-month follow-up (1.24 +/- 0.15 to 1.19 +/- 0.15 and 1.19 +/- 0.14). This may reflect changes at either or both of the anterior and posterior columns. CONCLUSION: Significant decreases in bone mineral density were noted above fused lumbar segments. This may have been related to immobilization or altered mechanics associated with arthrodesis. Trabecular bone of the axial skeleton is most responsive to change, compared with cortical bone, because of the higher metabolic activity. This may explain the reduction of bone mineral density at L3. Changes at L2 may have been related to altered loads at the anterior or posterior columns and should be further investigated.
STUDY DESIGN: Pain drawings were scored and their relationship to discographic pain responses was investigated. OBJECTIVES: The purpose of this study was to determine if there was a relationship between patients indicating pain in nonanatomic patterns on pain drawings (possibly suggestive of a tendency to overreport pain) and discographic pain responses, and in particular, if patients with abnormal drawings were more likely to provide false-positive discographic pain reports. SUMMARY OF BACKGROUND DATA: Patients with abnormal pain drawings have been found to have elevated scores on the hysteria and hypochondriasis scales of the Minnesota Multiphasic Personality Inventory. Elevations on these same two scales have been related to discordant discographic pain reports. METHODS: Pain drawings were completed by 170 patients the day of, but before computed tomography/discography. The drawings were scored as described by Ransford et al and classified as normal or abnormal. The number of levels at which a patient reported pain and the incidence of false-positive computed tomographic/discographic pain reports were compared for the two pain drawing groups. RESULTS: Patients with abnormal drawings reported pain at more levels than patients with normal ones. When dealing specifically with false-positive pain reports (pain reproduction on the injection of a nondisrupted disc), among the 105 patients in the normal group, only 13 (12.3%) reported false-positive pain. This was significantly less than the 50.0% (18 of 36) reporting false-positive pain in the abnormal group. The overall accuracy of pain drawings in differentiating patients with false-positive pain reports was 78.0% (110 of 141). CONCLUSIONS: There is a relationship between pain drawings and discographic pain responses. Pain drawings can help identify patients who may be likely to report pain on injection of a nondisrupted disc. While it was not totally sensitive to this occurrence, it can help identify at least some of the patients in whom pain responses should be interpreted cautiously.
STUDY DESIGN: An in vitro study to determine the intradiscal pressure changes during flexion in levels above a simulated fusion was performed. OBJECTIVES: To determine if intradiscal pressure increases more during flexion in discs above an instrumented spinal segment compared to an uninstrumented segment. SUMMARY OF BACKGROUND DATA: The progressive degeneration of intervertebral discs adjacent to a fused or fixed segment is a phenomenon that is noted but poorly understood. Intuitively, the degeneration appears to be a function of altered biomechanics of the motion segments in the spine. METHODS: Two intervertebral disc levels were evaluated, L3-L4 and L4-L5 from each of six fresh frozen cadaver spines. Pressure measurements were taken with the spine uninstrumented, with bilateral pedicle screw-rod instrumentation from L5 to S1, and with bilateral pedicle screw-rod instrumentation from L4 to S1. Pressure measurements were accomplished with Millar Mikro-Tip pressure transducers. The transducers were placed within the nucleus pulposus of L3-L4 and L4-L5 intervertebral discs. Pressure data were recorded by computer data acquisition. The pressure data were compared by intervertebral level and by the effects of added instrumentation. RESULTS: In general, the addition of instrumentation significantly affected the intradiscal pressure in the levels above a simulated fusion. The intradiscal pressure increased as the amount of levels involved in the simulated fusion increased. The intradiscal pressure increased as flexion motion increased. A greater increase was seen at the L4-L5 level than the L3-L4 level. When L5-S1 fixation was added, the intradiscal pressure increased. When L4-S1 fixation was added, the intradiscal pressure further increased. CONCLUSION: This study demonstrated increasing intradiscal pressures during flexion.
STUDY DESIGN: The value of adherence to selection criteria for laser disc decompression (LDD) was evaluated. A total of 204 patients who underwent LDDs were identified. Follow-up information could be obtained for 164 (80.8%) patients. Results were compared based on the selection criteria. SUMMARY OF BACKGROUND DATA: Laser disc decompression is a relatively new procedure. Few reports concerning outcome of LDD exist; and none deal specifically with patient selection. OBJECTIVE: This study compared the results of LDD performed among patients who met appropriate selection criteria with those who did not. Also, the value of discography in patient selection for LDD was investigated. METHODS: Two independent reviewers extracted data from patient charts. From this information, each patient was assigned to one of three groups: 1) those who met all selection criteria for LDD (leg pain, positive physical examination finding such motor, sensory, or reflex deficits, and/or straight leg raise, contained disc herniation confirmed by discography); 2) those who did not meet the selection criteria (had a normal physical examination, the presence of stenosis, spondylolisthesis, extruded disc fragment, leakage of discographic dye from the outer annulus, multiple prior lumbar surgeries); or 3) those who could not be assigned to either of the first two groups for reasons such as discography not being performed or inadequate physical examination data recorded in the chart. At 1 year follow-up, each patient was sent a questionnaire assessing outcome. Successful outcome was defined to be no subsequent lumbar surgery, the patient felt that LDD had helped, and if the patient was working before symptom onset, he was able to work at the time of follow-up. RESULTS: Among the 41 patients who met all selection criteria, the success rate was 70.7% (29/41); among patients who did not meet all the criteria, the success rate was only 28.6% (12/42); significantly less than in the first group (P < 0.005). Among patients who could not be assigned definitively to either of the first two groups, the success rate was 55.6% (45/81). Also, the success rate among patients with discographic confirmation of a contained disc herniation was significantly greater than among those who either did not have discography performed or extravasation of contrast was noted (70.7% vs. 44.4%, P < 0.035). CONCLUSIONS: These results emphasize the importance of strict adherence to appropriate selection criteria to obtain satisfactory results from LDD.
Explore the source record for details and available documents.
Patients who suffer from persistent pain for prolonged periods of time (6 months or more) are often influenced to an increasing extent by psychological factors. Patients begin to focus on their pain as the problem rather than its physical origin. This study evaluated the effectiveness of sensory deprivation in reducing pain in patients with chronic low-back pain. Sixty patients were divided into two groups of 30 patients each: One group underwent 1 hour of sensory deprivation; the other received a lecture on relaxation skills. In the group receiving sensory deprivation, statistically significant decreases in pain and stiffness were noted. Sensory deprivation is an effective treatment to reduce pain and thus interrupt the pain cycle in patients with chronic low-back pain.
Recently, there has been increased interest in less invasive spinal surgery techniques. This has led to the development of procedures such as automated percutaneous lumbar discectomy and arthroscopic microdiscectomy. Lasers are now used in many areas of medicine and may have applications in minimally invasive spinal surgery. A number of different laser systems have been evaluated for their effectiveness in removing disc tissue in the laboratory, but technical problems have limited their clinical use. Only the Nd:YAG (1,064 nm and 1,320 nm) and KTP (532 nm) systems have been used clinically. Unsuccessful clinical results were obtained with the 1,064 nm Nd:YAG, whereas the other two systems appeared to produce results similar to the present mechanical systems but required less time for disc removal. This paper discusses considerations for choosing a laser system for spinal applications and reviews the work performed in this area.
The technique for lumbar discography is not well standardized. To better understand lumbar pathology, we have developed a consistent, reproducible, and relatively simple procedure for lumbar discography. We describe our technique and discuss variables that may differ among individual lumbar discography procedures.
The computed tomography (CT)/discograms and discographic pain provocation reports of 291 clinical patients, 790 discs (mean age, 38; range, 17-79) were collected. The CT/discograms were classified separating anular disruption and degeneration and recording the pain provoked during discography as no pain, dissimilar, similar, or exact reproduction of the patient's clinical pain. Nondegenerated discs usually were found to be painless, and deteriorated discs painful. The proportion of severely degenerated but painless discs increased with age, as did the discs producing dissimilar pain. This may help explain the poor correlation of low-back pain with radiographic degenerative changes reported in previous epidemiologic studies.
CT/discograms of 107 low-back patients were classified by annular degeneration, annular disruption, and pain response. These parameters were compared with the heights of the corresponding discs. Disc height correlated significantly with degenerative annular changes. Comparison of the painless and exact reproduction groups at the L5-S1 level showed a significant increase in exact pain reproduction in narrow discs compared with normal discs. Discs demonstrating slight degenerative changes were often painful but narrowing was detected only when degeneration increased to moderate or severe levels. Some severely degenerated discs were painless and only part of the severe group was narrow. Measuring disc height is a poor method for detecting early, painful degeneration changes.
To identify characteristics of patient presentation that would help distinguish extraosseous spinal tumors from the more common herniated disc, nine cases of intraspinal tumors were reviewed. These nine patients were identified in a group of 744 patients who presented with symptoms similar to disc herniation but failed to respond to conservative care and underwent spinal surgery. This study indicates that intraspinal tumor should be suspected in patients with the following characteristics: 1) painless neurological deficit; 2) night pain or pain which increases in the supine position; 3) pain disproportionate to that normally expected with lumbar disc disease; 4) no change in symptoms after successful surgery for herniated disc; 5) elevated spinal fluid protein; or 6) a teenager with symptoms of disc herniation. Myelography is an effective radiologic procedure for the diagnosis of spinal tumor but MRI should be equally effective if the procedure includes a scan of the conus as well as cauda equina.
This is a report of 85 patients who underwent anterior lumbar interbody fusion (ALIF) for treatment of painful disc disruption (PDD) or symptomatic pseudarthrosis. The fusion rate was 80% by disc. The pseudarthrosis rate increased from 16% at L5-S1 to 21% and 31% at L4-5 and L3-4, respectively. There was a significant increase in pseudarthrosis rate in patients who smoked more than one pack per day. There was no difference in the fusion rate whether autogenous or cadaveric iliac crest graft or dowel versus tricortical block graft was used. Sixty-eight percent of patients were "able to work" after ALIF. The complication rate was low and retrograde ejaculation occurred in only one patient.
Proplast reconstruction of iliac crest defects resulting from bone grafts taken for anterior lumbar and cervical fusions is described. The procedure improves the cosmetic result, prevents postoperative muscle herniation and may decrease postoperative donor site pain. It is a simple procedure with low complication rate when performed in the manner described.
Disc deterioration and pain provocation in different low-back pain syndromes was studied using computed tomography (CT) discography. Data were prospectively collected for 300 patients (816 discs). Patients were classified by their pre-discography diagnosis of disc herniation (DH), degenerated disc (DD), lumbar syndrome (LS), lumbar radicular syndrome (LRS), or other. The CT/discograms were classified by discographic pain response, the amount of degeneration and annular disruption. Eighty-two percent of DH patients, 80% of DD, 56% of LS, and 59% of LRS patients had both positive discographic pain provocation and moderate or severe disc deterioration. The study indicates that intradiscal pathology plays a major role in nonspecific low-back pain syndromes.
A series of nine patients with post-discography discitis were evaluated to help delineate the clinical course. The most consistent sign was the marked exacerbation of neck or back pain. This then was followed by an elevated sedimentation rate at an average of 20 days, followed by a positive bone scan at an average of 33 days. Of note is that seven patients initially had negative bone scans at an average of 18 days. Five out of nine patients had changes on plain roentgenograms between 14 and 51 days after discography. Magnetic resonance imaging was performed in six patients; two of these patients were scanned twice. Three scans were negative and five were positive (2 patients initially had negative scans that later became positive). The course of lumbar discitis ranged from 8 to 11 weeks, and cervical discitis from 6 to 7 weeks, with the latter usually resulting in spontaneous fusion.
A new classification method for CT/discography was developed. The Dallas discogram description (DDD) related five separate categories of information. Degeneration and annular disruption were regarded as separate phenomena. Additionally, provoked pain response, contrast volume, and miscellaneous information were recorded. Discogram findings of 59 patients with low-back and/or leg pain were graded according to the new method and compared with standard methods using routine anteroposterior and lateral discographic images. Findings from routine discography and CT/discography were graded and correlated with myelographic and plain computerized axial tomography (CAT) scans. This study demonstrated that the contrast-enhanced axial view provided by CT/discography served as a useful projection for demonstrating disc pathology. CT/discography analyzed according to DDD offered a more sensitive discriminator of disc degeneration from annular disruption (disc protrusion/leaking). This evaluation can be recommended as the procedure of choice when revision of spine surgery is considered or when there is an equivocal or negative correlation between clinical information and myelography or CAT scan.