Patient satisfaction with spinal cord stimulation for predominant complaints of chronic, intractable low back pain.

BACKGROUND CONTEXT: Results of subsequent surgical intervention in patients with intractable pain after lumbar spine surgery are typically worse than for initial surgery, particularly in those with predominant complaints of back pain rather than lower extremity pain. Spinal cord stimulation (SCS) has been found to yield good results in patients with primary complaints of intractable lower extremity pain. Technological advances have broadened the indications for this treatment. PURPOSE: The purpose of this study was to evaluate patient satisfaction after SCS in the treatment of patients with predominant complaints of chronic, intractable, low back pain. STUDY DESIGN/SETTING: Data were collected from retrospective chart review and patient follow-up questionnaire. Patients were treated at a spine specialty center. PATIENT SAMPLE: The study group consisted of the consecutive series of our first 41 patients who underwent SCS for predominant complaints of low back pain. The mean symptom duration was 82.9 months, and the mean age was 47.9 years (range, 28-83 years). All but three patients had previously undergone lumbar spine surgery (mean, 2.3 prior surgeries). OUTCOME MEASURES: At the time of follow-up (5.5-19 months after SCS implantation), patients completed questionnaires assessing their satisfaction with their outcome, if they would have the procedure again knowing what their outcome would be and if they would recommend SCS to someone with similar problems. In determining outcome, a negative response was assigned for patients who had the device removed. A worst-case analysis was also conducted in which a negative response was assigned for patients lost to follow-up or who failed to respond to a particular question. Data were also collected on complications and re-operations. METHODS: All trial stimulation procedures were performed under local anesthetic with the patient providing feedback concerning pain relief achieved with various lead placements and settings. If one lead did not provide acceptable relief in all the areas needed, placement of a second lead was pursued. If the patient failed to maintain acceptable pain relief (> or =50% pain relief) during a multiday trial period, the leads were removed. If adequate relief was maintained during the trial period, the receiver was implanted. RESULTS: Responses to the follow-up questionnaire indicated that 60% of patients considered themselves improved from their preoperative condition and the remaining 40% did not; 78.1% of patients would recommend SCS to someone with similar problems, 69.0% were satisfied, 75.0% would have the procedure performed again if they had known their outcome before implantation. Among the 36 patients in whom the system was implanted, it was later removed in 4 because of lack of sufficient pain relief. Other re-operations included repositioning of the leads to regain pain relief in the areas needed, replacement of a malfunctioning unit and revision of lead extension wires. CONCLUSIONS: In this retrospective study, the majority of patients were satisfied with the results of SCS and would have the procedure again knowing what their outcome would be. These results suggest that further investigation of SCS is warranted in this difficult to treat patient population presenting with predominant complaints of chronic, intractable, axial low back pain.

The use of presurgical psychological screening to predict the outcome of spine surgery.

BACKGROUND CONTEXT: Several previous studies have shown that psychosocial factors can influence the outcome of elective spine surgery. PURPOSE: The purpose of the current study was to determine how well a presurgical screening instrument could predict surgical outcome. STUDY DESIGN/SETTING: The study was conducted by staff of a psychologist's office. They performed preoperative screening for spine surgery candidates and collected the follow-up data. PATIENT SAMPLE: Presurgical screening and follow-up data collection was performed on 204 patients who underwent laminectomy/discectomy (n=118) or fusion (n=86) of the lumbar spine. OUTCOME MEASURES: The outcome measures used in the study were visual analog pain scales, the Oswestry Disability Questionnaire, and medication use. METHODS: A semi-structured interview and psychometric testing were used to identify specific, quantifiable psychological, and "medical" risk factors for poor surgical outcome. A presurgical psychological screening (PPS) scorecard was completed for each patient, assessing whether the patient had a high or low level of risk on these psychological and medical dimensions. Based on the scorecard, an overall surgical prognosis of "good," "fair," or "poor" was generated. RESULTS: Results showed spine surgery led to significant overall improvements in pain, functional ability, and medication use. Medical and psychological risk levels were significantly related to outcome, with the poorest results obtained by patients having both high psychological and medical risk. Further, the accuracy of PPS surgical prognosis in predicting overall outcome was 82%. Only 9 of 53 patients predicted to have poor outcome achieved fair or good results from spine surgery. CONCLUSIONS: These findings suggest that PPS should become a more routine part of the evaluation of chronic pain patients in whom spine surgery is being considered.

A meta-analysis of autograft versus allograft in anterior cervical fusion.

We performed a metaanalysis of one- and two-level anterior cervical interbody fusion (ACDF) on data derived from published, peer-reviewed journal articles to determine whether there is a difference in fusion rate, graft complications, or clinical outcome in patients undergoing ACDF according to whether autograft or allograft was used. ACDF is a common procedure for cervical spondylotic radiculopathy. Most published studies comparing autograft and allograft have not demonstrated any difference between grafts. The medical literature dating from 1955 was reviewed. Of 395 titles, only four studies comparing autograft with allograft in ACDF were appropriate for this analysis. The data from these studies--310 patients and 379 intervertebral levels were pooled and statistical methods were applied. For both one- and two-level ACDF, autograft demonstrated a higher rate of radiographic union and a lower incidence of graft collapse. It was not possible to ascertain whether autograft is clinically superior to allograft. Although autograft has a higher fusion rate than allograft, clinical results do not depend solely on radiographic results. The risk of graft site morbidity and patient preference should be considered when choosing the type of graft for this operation.

The relationship of disability (Oswestry) and pain drawings to functional testing.

UNLABELLED: There was much enthusiasm about the development of computerized dynamometry in providing large quantities of data to objectively assess muscle performance. However, a much more basic issue arose questioning what these machines actual measure, particularly in pain populations. The purpose of the present study was to determine whether patients' self-reported disability and pain expression, as evaluated with simple questionnaires, were related to isokinetic performance in low back pain patients. METHOD: Oswestry Disability Questionnaires and pain drawings were collected from 76 patients undergoing isokinetic testing upon entering a physical rehabilitation program. Isokinetic trunk testing was performed in the standing position and results recorded for flexion and extension at speeds of 50 degrees, 100 degrees, and 150 degrees per second. RESULTS: Patients indicating minimal disability on the Oswestry questionnaire performed better than those indicating greater levels of disability (P < 0.05; ANOVA with Tukey adjustment for multiple comparisons). Patients with greater pain drawing scores, indicating unusual pain patterns, performed more poorly during isokinetic testing than those with normal drawings (P < 0.05). Regression analysis revealed that the lifting question from the Oswestry questionnaire, pain drawings scores, and sex were all significantly related to isokinetic performance and could account for 37.6-48.1% of the variance in performance (varying with speed of test). CONCLUSIONS: The results of this study indicate that isokinetic test values are significantly influenced by a patient's self-reported disability and pain expression, which can be evaluated using simple tools such as pain drawings and the Oswestry questionnaire. This study supports the supposition that dynamometry testing is related to factors other than muscle performance.

Repeatability of pain drawings in a low back pain population.

STUDY DESIGN: This is a prospective test-retest repeatability study. OBJECTIVE: The primary purpose of this study was to determine the test-retest repeatability, using a variety of scoring methods, of pain drawings in a group of chronic low back pain patients. The intraevaluator repeatability for the methods requiring subjective interpretation was also evaluated. SUMMARY OF BACKGROUND DATA: Pain drawings have been used in a variety of applications, including documentation of symptom location, as a tool for diagnosis and as a psychological screening tool. Accordingly, there have been several methods described for interpreting the drawings and several groups have investigated evaluators' abilities to replicate their interpretation. However, there has been less investigation of patients' consistency in completing the drawings. METHODS: The intraevaluator repeatability was determined for the two scoring methods requiring subjective interpretation by the evaluator rescoring the drawings 2 weeks after the initial scoring. To determine repeatability, drawings were completed on two occasions by 75 patients. Patients who indicated on a questionnaire that there had been no change in their pain location since their first clinic visit (the day the first drawing was completed) were included in the study. This subgroup consisted of 45 patients who completed pain drawings on two occasions separated by a mean of 244.2 days (range, 26-1197 days). Repeatability was assessed for several scoring methods described in the literature: penalty point system, overall visual inspection, body regions, and a grid method. RESULTS: Patients were consistent in completing the drawings, assessed by the various scoring methods. The worst repeatability values were for some of the sensation types. DISCUSSION: As reported by others, the intraevaluator repeatability was high. The results of this study, finding acceptable repeatability for most scoring methods for pain drawing completed on occasions separated by a relatively long period of time, support that the pain drawing is a stable instrument for use in chronic back pain patients.

The relation between cervical discographic pain responses and radiographic images.

OBJECTIVE: The purpose of this study was to investigate the relation between cervical discographic pain responses and radiographic images. DESIGN: Records were reviewed for a series of patients who had undergone cervical discography. SETTING: All patients were being treated at a spine specialty clinic. PATIENTS: A total of 269 discs were studied in 161 discographic procedures in patients with neck, shoulder, or arm pain. All patients underwent other diagnostic procedures before discography, including magnetic resonance imaging, computed tomography (CT), and CT/myelography. INTERVENTIONS: During the injection of contrast in each disc evaluated, the patient was asked if any pain was felt, and if so, was it similar or dissimilar to the pain typically experienced. OUTCOME MEASURES: Results were determined by analyzing the pain responses during disc injection with respect to imaged pathology seen on the axial CT discographic image of the disc. Results were further analyzed based on patient age. RESULTS: There was a significant relation between the radiographic image of the disc and the results of clinical pain provocation (p < 0.01; chi2). Among the 35 discs appearing as normal, clinical pain was provoked in only 14.3%. Among the 234 discs appearing as abnormal, clinical pain was provoked in 77.8%. The mean age of the patients with painless radiographically abnormal discs was significantly greater than that of the patients in the other subgroups of the study population. CONCLUSIONS: There was good agreement between the radiographic appearance of the disc and the pain provocation results. Discs that were painless but disrupted were found among older patients. Among such patients, discography may be particularly helpful in differentiating clinically significant abnormalities from those associated with aging.

Laparoscopic approach to L4-L5 for interbody fusion using BAK cages: experience in the first 58 cases.

STUDY DESIGN: Operative reports were reviewed for patients who underwent laparoscopic fusion at the L4-L5 level and information regarding the mobilization of the vessels was recorded. OBJECTIVE: The purpose of this study was to describe variations in the approach used to address anatomical variations in the location of the great vessel bifurcation in the region of the L4-L5 intervertebral disc space when performing laparoscopic interbody fusion procedures. SUMMARY OF BACKGROUND DATA: Recent interest in laparoscopic spine surgery using threaded cages has resulted in questions regarding the ability to safely access the L4-L5 disc using this approach. The laparoscopic transperitoneal approach to L5-S1 is below the bifurcation of the great vessels, thus requiring minimal mobilization of the iliac vessels. However, the transperitoneal approach to L4-L5 may be complicated by the bifurcation of the great vessels anterior to this disc space. Difficulty in placing two cages may occur if the vessels cannot be adequately mobilized. METHODS: Data were collected for the consecutive series of the first 58 patients (40 males, 18 females; mean age 42.5 years) undergoing laparoscopic anterior lumbar interbody fusion (ALIF) at the L4-L5 level using BAK cages. Operative notes were reviewed to determine variations in the operative approach. In particular, it was recorded if the L4-L5 disc was accessed above, or below the bifurcation of the aorta and the vena cava, or between these structures. The blood loss, operative time, and length of hospitalization were compared with respect to approach variation. RESULTS: In 30 patients, the L4-L5 disc was accessed above the great vessel bifurcation, in 18 patients below the bifurcation, and in the remaining 10 patients, by passing between the vessels. There were no statistically significant differences in the operative time, blood loss, or length of hospitalization with respect to the approach used. Three patients were converted to open procedures as a result of bleeding from segmental veins. None required transfusions and there were no postoperative sequelae. In two patients, successful endoscopic repair of segmental vein avulsion from the vena cava was performed using endoscopic loop ligatures. One patient had a secondary procedure to remove a cage that was causingnerve irritation, and one patient reported retrograde ejaculation after a two level fusion. Another patient, in whom a posterior herniation was removed, later presented with a cerebrospinal fluid leak. Most of the operative complications occurred early in the series. CONCLUSIONS: Laparoscopic transperitoneal approach to L4-L5 for insertion of threaded fusion cages is feasible. The laparoscopic L4-L5 procedure can be accomplished with few complications, provided a dedicated team of collaborative surgeons with experience in laparoscopic spine techniques is employed. Variations in vascular anatomy did not prevent successful insertion of two threaded fusion cages.

Relation between pain location and disc pathology: a study of pain drawings and CT/discography.

OBJECTIVE: The purpose of this study was to determine whether pain location indicated in pain drawings was related to the specific lumbar disc level(s) that was abnormal in appearance and painful upon discographic injection. DESIGN: Data were collected prospectively. SETTING: This study was conducted in a spine specialty clinic. PATIENTS: The study group consisted of 187 patients (118 men, 69 women; mean age = 37.2 years, range = 18-62 years) with low back pain with or without leg pain. All patients were undergoing computed tomography (CT)/discography at the three lowest lumbar levels for diagnostic purposes. INTERVENTIONS: Pain drawings were completed the day of but prior to undergoing discography. Discographic pain responses were recorded with respect to the similarity to the patient's clinical symptoms. Pain drawings were classified based on the presence or absence of pain in five areas: low back and/or buttocks, posterior thigh, posterior leg, anterior thigh, and anterior leg. The drawings were scored with the system described by Ransford et al. (1976, Spine 1: 127-34), and those likely to be indicative of psychological problems were analyzed separately (n = 43). OUTCOME MEASURES: Results were determined by analyzing the relation between the location of pain in the drawings and the specific lumbar disc level(s) found to be painful and disrupted by discography. RESULTS: There was a significant relation between pain location indicated in the drawing and the lumbar disc level(s) identified as clinically painful and disrupted by CT/discography (p < 0.05, chi-square). Pain limited to the low back and buttocks was frequently associated with the absence of disc pathology (58.3%). When pain in the posterior thigh or leg was present but there was no pain in the anterior drawing, patients frequently had a positive L5-S 1 disc (> or =75%). In patients with anterior thigh pain, with or without posterior thigh or leg pain, the L4-5 disc was frequently symptomatic (>63%). The pattern of no posterior thigh or leg pain but with pain radiating into the leg anteriorly was most commonly associated with the L3-4 disc (71.4%). CONCLUSIONS: The results of this study indicate that pain drawings may be helpful in identifying which specific discs are associated with pain complaints. As with any evaluation, the drawings should be considered in combination with findings from other assessments.

Relationship of pain drawings to invasive tests assessing intervertebral disc pathology.

It has been found that the pain patterns in pain drawings are related to the presence of herniated disc identified by myelography. The purpose of this study was to determine whether the pattern of pain in the drawings or the type of pain indicated (aching, burning, numbness, pins and needles, stabbing) was related to the presence of symptomatic disc pathology identified by CT/discography. In a subgroup of patients who underwent myelography, the relationship of the drawings to myelographic findings was also investigated. Pain drawings were completed by 187 patients with low back and/or radicular pain who were undergoing CT/discography. The drawings were scored in two ways, first by the system described by Ransford and secondly by visual inspection. They were classified as being indicative, or not, of disc pathology. The CT/discograms were classified as disrupted, or not, and the pain responses were recorded upon injection of each disc, based on the similarity of the pain provoked to clinical symptoms. Among the 133 patients with discogenic pain confirmed by discography, 110 (82.7%) had pain drawings that were classified as indicative. Among the 45 patients without discogenic pain, 29 (64.4%) had pain drawings classified as non-indicative. Patients with discogenic pain used more symbols indicating burning pain and aching pain than did non-discogenic pain patients. Our results confirmed those reported earlier by Uden, who found a relationship between the pattern of pain in the drawings and myelographic findings. Pain drawings may be helpful in the diagnosis of symptomatic disc pathology.

Vibration pain provocation can improve the specificity of MRI in the diagnosis of symptomatic lumbar disc rupture.

OBJECTIVE: The purpose of this study was to determine if vibration pain provocation could be combined with magnetic resonance imaging (MRI) to increase its specificity in identifying symptomatic disc disruption identified by discography. DESIGN: Prospective single-blind study. SETTING: Data were collected at a spine specialty clinic and at a diagnostic imaging center. PATIENTS: A total of 206 discs in 78 patients (41 males, 37 females; average age, 39.7 years; range, 18-73 years) were evaluated by MRI, spinous process vibration, and discography. INTERVENTIONS: A hand-held prototype vibrator was applied to the spinous process of each intervertebral disc level to be evaluated. The type of pain provoked with vibration as well as with discography was recorded as painless, dissimilar to clinical pain, or similar/exact reproduction of clinical pain. The discograms and MRI scans were scored on a 0-4 scale. A system was defined for combining the vibration results with MRI. OUTCOME MEASURES: The results of the vibration and MRI were compared with the results of computed tomography/discography to determine how well the results of the evaluations agreed. RESULTS: Vibration pain provocation agreed with discographic pain provocation in 70.9% of the discs. The specificity of MRI compared with discographic findings was only 55.7%. However, this figure improved significantly to 81.3% when relying on the vibration pain provocation in discs with mild or moderate disruption. The sensitivity of the combined evaluation was 85.9% and the accuracy 83.0%. CONCLUSIONS: A small hand-held vibrator could produce pain provocation results similar to those obtained by discography. Results of this noninvasive pain provocation method can improve the specificity and accuracy of MRI in identifying symptomatic disc lesions.

Degree of disc disruption and lower extremity pain.

STUDY DESIGN: Data were collected prospectively from patient-completed pain drawings, lumbar discographic pain responses, and computed tomographic-discographic images. OBJECTIVES: To determine if there were differences in pain location or the type of pain associated with the severity of symptomatic disc disruption. SUMMARY OF BACKGROUND DATA: Lower extremity pain related to spinal pathology was for a long time attributed primarily to nerve root compression. However, this simple model could not explain all lower extremity pain. Other mechanisms such as biochemical agents have been implicated. Also, nerve endings have been found in the outer layers of the anulus. Such endings could be associated with pain referred from the disc into the lower extremities. Pain drawings have been used in several studies to investigate various back pain origins and provide an easily administered method to document pain location. METHODS: Pain drawings were completed by 187 patients undergoing discography at the three lowest levels. The study group consisted of 118 men and 69 women with an average age of 37.2 years (range, 18-62 years). Computed tomographic discograms were scored using the Dallas discogram description, which assigns separate scores for discs with disruption of outer anular fibers (Grade 2) and those with disruption of the outermost anular layers associated with deformation or herniation of the outer anular well (Grade 3). The pain response provoked with each disc injection was recorded as pressure only or painless, pain dissimilar to clinical symptoms, similar to symptoms, or the exact reproduction of clinical pain, in this study, the similar and exact reproduction responses were combined and considered to be "symptomatic." The drawings were classified based on the presence or absence of pain in three regions: low back or buttocks, thigh, and leg. The drawings were also scored using the system described by Ransford, and those that were likely to be indicative of psychological problems were analyzed separately (N = 43). RESULTS: There was no significant difference in the distal location of lower extremity pain among patients whose most severe symptomatic disc disruption was a Grade 2 compared with those with symptomatic Grade 3 disruption (62.2% vs. 61.7%; P > 0.75; chi-square). The figure was similar for patients with both symptomatic Grade 2 and 3 disruption (72.7%). However, patients with symptomatic Grade 2 disruption used significantly more symbols to describe their pain, and in particular aching pain, than did those with symptomatic Grade 3 disruption. CONCLUSIONS: These results indicate that disc disruption passing into the outer layers of the anulus, but not resulting in deformation of the outer anular wall, was as frequently associated with lower extremity pain as were discs with more severe disruption deforming the outer anular wall; however, they were associated with a greater degree of aching pain. These findings support that lower extremity pain may be referred from the disc.

Complications of cervical discography: findings in a large series.

The use of cervical discography remains controversial. Recently in a small patient group, a high complication rate was reported. The purpose of this study was to determine the incidence of complications associated with cervical discography. Data from 161 cervical discography procedures, involving 269 disc injections, were recorded. There were four complications; thus the complication rate was 2.48% based on the number of procedures and 1.49% based on the number of disc injections. The complications were two cases of discitis, one postinjection hematoma, and one patient developed significant headache pain after the disc injection. Reports of high complication rates associated with cervical discography and serious outcomes from them should serve as a warning that the procedure does have associated risks, and great care is warranted. However, based on the results of our study, discography is not an inherently unsafe procedure. It can be accomplished with few complications when performed in sterile conditions by those well experienced with cervical disc injections.

Prospective outcome evaluation of spinal cord stimulation in patients with intractable leg pain.

STUDY DESIGN: The results of spinal cord stimulation were prospectively evaluated using both subjective patient self-report measures and objective physical functional testing. OBJECTIVES: The purpose of this study was to evaluate prospectively the effects of spinal cord stimulation implantation, performed with the patient awake and providing feedback, in patients with primary reports of intractable leg pain. SUMMARY OF BACKGROUND DATA: Spinal cord stimulation has been used for treating chronic pain of many types. However, even among those with intractable lower extremity pain, the outcome results have shown great variability. METHODS: The surgical procedure was performed with the patient awake and providing feedback to ensure optimal pain relief from the lead placement. The study group comprised 40 patients, ranging in age from 28 to 86 years. The average symptom duration was 65.4 months, and the average number of prior lumbar spine surgeries was 2.3 (range, 1 to 8). The primary data collection periods were preoperative, 6 weeks after, and 12 and 24 months after surgery. RESULTS: Statistically significant improvement in isometric lower extremity function was demonstrated 6 weeks after the spinal cord stimulation implantation. In the more painful leg, the performance increased from 457.5 ft-lb-sec to 629.8 ft-lb-sec (P < 0.01). The performance remained significantly improved at the 12- and 24-month follow-ups. Significant improvement was demonstrated on the physical scale of the Sickness Impact Profile at 6 weeks. At 24 months, all three scales (physical, psychological, and other) as well as the total score were significantly improved. Statistically significant decreases in pain, assessed by changes in visual analog scale scores, were noted in the legs, when walking, and in overall lifestyle. The use of narcotic medication decreased at all follow-up periods. At least 66% of the patients who were taking narcotics before spinal cord stimulation were taking reduced amounts or no narcotics 2 years later. At the time of the 24-month follow-up, at least 70% of patients reported that the procedure helped them, and would recommend it to someone with similar symptoms. CONCLUSIONS: Spinal cord stimulation implantation can result in improved physical function and decreased pain in patients who are carefully screened and in whom the implantation is performed with the patient awake to help ensure optimal pain-relieving lead placement.

Discographic pain report. Influence of psychological factors.

STUDY DESIGN: The possibility of a relationship between discographic pain responses and Minnesota Multiphasic Personality inventory scores was investigated. OBJECTIVES: To determine if patients with elevated Minnesota Multiphasic Personality Inventory scale scores were more likely to report pain on the injection of a nondisrupted disc than were patients without such high scores. SUMMARY OF BACKGROUND DATA: In general, injection into disrupted discs provokes pain, whereas injection into nondisrupted discs does not. However, discordant results are sometimes obtained and create a more difficult diagnostic challenge. METHODS: The primary study group was composed of 72 patients who underwent computed tomography/discography at the three lowest lumbar levels for diagnostic purposes and completed the Minnesota Multiphasic Personality Inventory. RESULTS: The mean scores on the Minnesota Multiphasic Personality Inventory hypochondriasis and hysteria scales were significantly greater for patients reporting reproduction of clinical pain than for patients not reporting pain on injection of a nondisrupted disc (hypochondriasis: 77.2 vs. 68.6, P < 0.01; hysteria: 74.5 vs. 68.3, P < 0.05). The scores on the depression scale followed a similar trend (68.6 vs. 63.6, P < 0.15). Multivariate analysis, adjusting the means for possible confounding effects of age, symptom duration, and sex, did not alter the results. CONCLUSIONS: Discographic pain reports are not only related to anatomic abnormalities, but are influenced by personality as assessed by the Minnesota Multiphasic Personality Inventory. Patients with elevated scores on the hypochondriasis, hysteria, and depression scales may tend to overreport pain during discographic injection. Among such patients, even those with a concordant computed tomography/discographic image, selection of therapeutic modalities should be made with caution.

Lumbar discography. Position statement from the North American Spine Society Diagnostic and Therapeutic Committee.

STUDY DESIGN: A comprehensive review of the literature dealing with lumbar discography was conducted. OBJECTIVE: The purpose of the review was to generate a position statement addressing criticisms of lumbar discography, identify indications for its use, and describe a technique for its performance. SUMMARY OF BACKGROUND DATA: Lumbar discography remains a controversial diagnostic procedure. There are concerns about its safety and clinical value, although others support its use in specific applications. METHODS: Articles dealing with lumbar discography were reviewed and summarized in this report. RESULTS: Most of the recent literature supports the use of discography in select patients. Although not to be taken lightly, many of the serious and high complication rates were reported before 1970 and have decreased since because of improvement in injection technique, imaging, and contrast materials. CONCLUSIONS: Most of the current literature supports the use of discography in select situations. Particular applications include patients with persistent pain in whom disc abnormality is suspect, but noninvasive tests have not provided sufficient diagnostic information or the images need to be correlated with clinical symptoms. Another application is assessment of discs in patients in whom fusion is being considered. Discography's role in such cases is to determine if discs within the proposed fusion segment are symptomatic and if the adjacent discs are normal. Discography appears to be helpful in patients who have previously undergone surgery but continue to experience significant pain. In such cases, it can be used to differentiate between postoperative scar and recurrent disc herniation and to investigate the condition of a disc within, or adjacent to, a fused spinal segment to better delineate the source of symptoms. When minimally invasive discectomy is being considered, discography can be used to confirm a contained disc herniation, which is generally an indication for such surgical procedures. Lumbar discography should be performed by those well experienced with the procedure and in sterile conditions with a double needle technique and fluoroscopic imaging for proper needle placement. Information assessed and recorded should include the volume of contrast injected, pain response with particular emphasis on its location and similarity to clinical symptoms, and the pattern of dye distribution. Frequently, discography is followed by axial computed tomography scanning to obtain more information about the condition of the disc.

Early changes in bone mineral density above a combined anteroposterior L4-S1 lumbar spinal fusion. A clinical investigation.

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.

The association between pain drawings and computed tomographic/discographic pain responses.

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.

Laser disc decompression. The importance of proper patient selection.

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.

The relationship of facet tropism to degenerative disc disease.

The role of facet tropism (asymmetry) in the pathogenesis of degenerative disc disease is unknown, and several conflicting reports have been published. We studied this association using CT/discography performed at 324 lumbar levels (108 patients). The stage of disc degeneration as well as the patient's pain response upon discographic injection were scored using a standardized protocol. The facet angles were measured directly from the axial CT/discographic images and defined, in each case, as the angle formed by the facet orientation with respect to the midsagittal plane. The facet tropism angle was defined as the difference between the left and right facet angles at each disc level. The mean and standard deviation (SD) of the tropism angles were calculated. From this calculation, each pair of facet joints was classified as symmetric (within 1 SD of the mean), moderately asymmetric (between 1 and 2 SD), or severely asymmetric (beyond 2 SD of the mean). There were no differences in degree of disc degeneration or pain response with respect to the facet tropism. The total facet angle was also studied. The total facet angle was greater at the more caudal levels. The total angle size was not associated, however, with disc degeneration or pain provocation. These findings do not support the hypothesis that there is an association between facet tropism and degenerative lumbar disc disease.