Pain-drawing does not predict the outcome of fusion surgery for chronic low-back pain: a report from the Swedish Lumbar Spine Study.

Despite a widespread use of pain drawing in the selection of patients for surgical and non-surgical treatment, its value as a predictor of outcome is still not well documented. In a prospective multicentre randomised controlled trial of surgical and non-surgical treatment for chronic low-back pain (CLBP), two hypotheses were tested: (1). Pain drawing predicts outcome of treatment for CLBP, (2). Pain drawing is associated with psychological characteristics of patients with CLBP. Two hundred and sixty-four patients with severe CLBP of long duration completed pain drawings as part of a battery of questionnaires prior to treatment. They were followed up at 2 years post-treatment, with renewed completion of questionnaires. Outcome was measured in three ways: patient global assessment, change of disability/pain, and work status. The pain drawing was analysed by four different methods. The association between the pain drawings and outcomes was analysed. Personality traits and depressive symptoms were evaluated in the psychological assessment. None of the four methods of interpretation of the pain drawings demonstrated any significant association with outcome, in either the surgical or the non-surgical group. The pain drawing was associated with pre-treatment back pain intensity and depressive symptoms. No predictive value of the pain drawing regarding the outcome of treatment of CLPB was demonstrated. The concept of "organic/non-organic" pain in conjunction with chronic low-back pain is not supported by the results of the present study.

The clinical importance of changes in outcome scores after treatment for chronic low back pain.

When measuring treatment effect in chronic low back pain with multi-item outcome instruments, it is necessary, both for clinical decision-making and research purposes, to understand the clinical importance of the outcome scores. The aims of the present study were three-fold. Firstly, it aimed to estimate the minimal clinically important difference of three multi-item outcome instruments (the Oswestry Disability Index, the General Function Score and the Zung Depression Scale) and of the visual analogue scale (VAS) of back pain. Secondly, it aimed to estimate the error of measurement of these instruments; and its third aim was to describe the clinical meaning of score change. The study population consisted of 289 patients treated surgically or non-surgically in a randomised controlled trial. The minimal clinically important difference was estimated with patient global assessment as the external criterion. It was compared with the standard error of measurement of the instruments. The individual items of the instruments were compared for score changes related to improvement and deterioration. The standard error of measurement of the Oswestry Disability Index, the General Function Score and the Zung Depression Scale was 4, 6 and 3 units, respectively. The 95% tolerance interval was 10, 16 and 8 units, respectively. The minimal clinically important difference was 10, 12 and 8-9 units, respectively, thus not significantly exceeding the tolerance interval. The minimal clinically important difference of VAS back pain was 18-19 units, well exceeding the 95% tolerance interval, which was 15 units. Improvement after treatment for chronic low back pain tends to occur to a greater extent in sleep disturbance, ability to do usual things and psychological irritability, but to a lesser extent in the ability to sit, stand and lift. We conclude that the VAS of back pain is responsive enough to detect the minimal clinically important difference, whereas the smallest acceptable score changes of the Oswestry Disability Index, the General Function Score and the Zung Depression Scale may require an increase to exceed the 95% tolerance interval when used for clinical decision making and for power calculation. Despite improvement after treatment, the ability to sit, stand and lift, remain notable problems.

Predictors of outcome in fusion surgery for chronic low back pain. A report from the Swedish Lumbar Spine Study.

Despite the continuous development of surgical techniques and implants, a substantial number of patients still undergo surgery for chronic low back pain (CLBP) without any benefit, or even become worse. With the aim of finding predictors of functional and work status outcome, 264 patients with severe CLBP of long duration, randomised to surgical or non-surgical treatment, were characterized by socio-demographic, clinical, radiological and psychological variables. The variables were estimated as predictors of outcome at the 2-year follow-up. Univariate and multiple logistic regression analyses were used in both treatment groups. We found that a personality characterized by low neuroticism and low disc height were significant predictors of functional improvement after surgical treatment. Depressive symptoms predicted functional improvement after non-surgical treatment. Work resumption was predicted by low age and short sick leave in the surgical group, and by short sick leave in the non-surgical group. We conclude that improved selection of successful surgical candidates with CLBP seems to be promoted by attention to severe disc degeneration, evaluation of personality traits and shortening of preoperative sick leave.

2001 Volvo Award Winner in Clinical Studies: Lumbar fusion versus nonsurgical treatment for chronic low back pain: a multicenter randomized controlled trial from the Swedish Lumbar Spine Study Group.

STUDY DESIGN: A randomized controlled multicenter study with a 2-year follow-up by an independent observer. OBJECTIVES: To determine whether fusion of the lower lumbar spine could reduce pain and diminish disability more effectively when compared with nonsurgical treatment in patients with severe chronic low back pain (CLBP). SUMMARY OF BACKGROUND DATA: The reported results after fusion surgery on patients with CLBP vary considerably, and the evidence of treatment efficacy is weak in the absence of randomized controlled studies. PATIENTS AND METHODS: A total of 294 patients referred to 19 spinal centers from 1992 through 1998 were randomized blindly into four treatment groups. Patients aged 25-65 years with CLBP for at least 2 years and with radiologic evidence of disc degeneration at L4-L5, L5-S1, or both were eligible to participate in the study. The surgical group (n=222) included three different fusion techniques, not analyzed separately in this study. Patients in the nonsurgical group (n=72) were treated with different kinds of physical therapy. The surgical group comprised 49.5% men, and the mean age was 43 years. The corresponding figures for the nonsurgical group were 48.6% and 44 years. The patients had suffered from low back pain for a mean of 7.8 and 8.5 years and been on sick leave due to back pain for a mean of 3.2 and 2.9 years, respectively. The Visual Analogue Scale (VAS) was used to measure pain. The Oswestry Low Back Pain Questionnaire, the Million Score and the General Function Score (GFS) were used to measure disability. The Zung Depression Scale was used to measure depressive symptoms. The overall result was assessed by the patient and by an independent observer. Records from the Swedish Social Insurance were used to evaluate work disability. Patients who changed groups were included in the analyses of significance according to the intention-to-treat principle. RESULTS: At the 2-year follow-up 289 of 294 (98%) patients, including 25 who had changed groups, were examined. Back pain was reduced in the surgical group by 33% (64 to 43), compared with 7% (63 to 58) in the nonsurgical group (P=0.0002). Pain improved most during the first 6 months and then gradually deteriorated. Disability according to Oswestry was reduced by 25% (47 to 36) compared with 6% (48 to 46) among nonsurgical patients (P=0.015), according to Million by 28% (64 to 46) compared with 8% (66 to 60) (P=0.004), and accordingtoGFS by 31% (49 to 34) compared with 4% (48 to 46) (P=0.005). The depressive symptoms, according to Zung, were reduced by 20% (39 to 31) in the surgical group compared with 7% (39 to 36) in the nonsurgical group (P=0.123). In the surgical group 63% (122/195) rated themselves as "much better" or "better" compared with 29% (18/62) in the nonsurgical group (P<0.0001). The "net back to work rate" was significantly in favor of surgical treatment, or 36% vs. 13% (P=0.002). The early complication rate in the surgical group was 17%. CONCLUSION: Lumbar fusion in a well-informed and selected group of patients with severe CLBP can diminish pain and decrease disability more efficiently than commonly used nonsurgical treatment.

The General Function Score: a useful tool for measurement of physical disability. Validity and reliability.

The General Function Score (GFS) is a disease-specific instrument consisting of nine items focusing on strict physical activities of daily living. It is intended as an alternative to the more complex scores of disability (such as the Oswestry Disability Index), serving as a complement to the quality of life instruments in the study of low back pain (LBP). It was developed from an original 17-item questionnaire, of which 11 of the items were tested for criterion validity in an observer-supervised performance test. Two items were excluded from further analysis because of too low a validity. The remaining nine-item GFS was tested for construct validity, reliability, feasibility and responsiveness in six different cohorts: 297 patients with chronic low back pain (cohort 1), an age- and sex-matched control group of 287 randomly allocated Swedish citizens (cohort 2), three separate groups of patients admitted for surgery due to low back disorders (cohorts 3-5) and outpatients with spinal disorders (cohort 6). Correlations were tested with the Spearman Rank correlation coefficient, differences between groups with the Mann-Whitney test and the internal consistency with the Cronbach's coefficient alpha. The GFS total scores showed correlations of 0.78, 0.81 and 0.88 in the three aspects of the performance test. The response rate was 98.3-100%. The mean time to complete the questionnaire was 1.2 min. The internal consistency was 0.69 and 0.86 in cohorts 1 and 2 respectively. The test-retest correlation was 0.88. The GFS showed a high responsiveness to difference and change. The effect size was 0.82-0.96 in surgically treated disc herniation and 0.55-0.85 in spondylolisthesis. The GFS is a highly valid and reliable instrument with good responsiveness and feasibility, useful for evaluation of physical disability.

The effect of surgery and remodelling on spinal canal measurements after thoracolumbar burst fractures.

Bone fragments in the spinal canal after thoracolumbar spine injuries causing spinal canal narrowing is a frequent phenomenon. Efforts to remove such fragments are often considered. The purpose of the present study was to evaluate the effects of surgery on spinal canal dimensions, as well as the subsequent effect of natural remodelling, previously described by other authors. A base material of 157 patients operated consecutively for unstable thoracolumbar spine fractures at Sahlgrenska University Hospital in Gothenburg during the years 1980-1988 were evaluated, with a minimum of 5-years follow-up. Of these, 115 had suffered burst fractures. Usually the Harrington distraction rod system was employed. Patients underwent computed tomography (CT) preoperatively, postoperatively and at follow-up. From digitized CT scans, cross-sectional area (CSA) and mid-sagittal diameter (MSD) of the spinal canal at the level of injury were determined. The results showed that the preoperative CSA of the spinal canal was reduced to 1.4 cm2 or 49% of normal, after injury. Postoperatively it was widened to 2.0 cm2 or 72% of normal. At the time of follow-up, the CSA had improved further, to 2.6 cm2 or 87%. The extent of widening by surgery depended on the extent of initial narrowing, but not on fragment removal. Remodelling was dependent on the amount of bone left after surgery. The study shows that canal enlargement during surgery is caused by indirect effects when the spine is distracted and put into lordosis. Remodelling will occur if there is residual narrowing. Acute intervention into the spinal canal, as well as subsequent surgery because of residual bone, should be avoided.

Management of chronic disabling low back pain with 360 degrees fusion. Results from pain provocation test and concurrent posterior lumbar interbody fusion, posterolateral fusion, and pedicle screw instrumentation in patients with chronic disabling low back pain.

STUDY DESIGN: A follow-up study conducted by an independent observer was performed on the authors' first 29 consecutive patients treated with concurrent posterior lumbar interbody fusion, posterolateral fusion, and pedicle screw instrumentation, for whom at least 2 years had transpired since the operation. OBJECTIVE: To evaluate the results of concurrent instrumented posterior lumbar interbody fusion and posterolateral fusion used to manage chronic disabling low back pain. SUMMARY OF BACKGROUND DATA: Patients chosen for surgery all had a history of chronic disabling low back pain exceeding 2 years and a sick leave period in excess of 6 months (average, 3.4 years). METHODS: From 1989 to 1993, 29 consecutive patients were surgically treated with fusion. The level of fusion was chosen depending on radiologic changes and results from a intradiscal injection provocation test. Bone union was verified by computed tomography scan with 1-mm-thin slices and sagittal reformation, and by a "second look" in all but three patients. All patients were evaluated subsequently by an independent observer in November 1995, 4.7 years after surgery on the average. RESULTS: Bone fusion was obtained in 27 of the 29 patients (93%). There was a highly significant reduction in back and leg pain measurements. Of the 29 patients, the results were excellent in 9 patients (31%), good in 6 patients (21%), fair in 6 patients (21%), and poor in 8 patients (27%). A total of 18 patients (62%) had returned to work. CONCLUSION: The authors consider posterior lumbar interbody fusion with concurrent posterolateral fusion and pedicle screw instrumentation a possible method for managing chronic disabling low back pain.

Determination of inter-spinous process distance in the lumbar spine. Evaluation of reference population to facilitate detection of severe trauma.

Fracture of a spinal segment with minimal or no compression of the vertebral body can be highly unstable. Screening for such an injury in the lumbar spine is often obstructed in a multi-injured patient, because of difficulty in obtaining adequate sagittal radiographs. The position of the spinous processes in relation to each other is the key for proper evaluation of the status of the posterior stabilising structures. The amount of separation or axial rotation of the posterior part of the vertebra that can occur before failure of the posterior structures has not been unambiguously defined. Despite this, it can be assumed that severe separation of the spinous processes indicates a more or less pronounced loss of mechanical support. An analysis of how the posterior spinous processes relate to each other on an anteroposterior (AP) radiograph could obviate this problem. A new, simple and reproducible radiographic tool is presented for screening of an eventual rupture of posterior structures of the lumbar spine. This method is based on measurements of the variation in interspinal process distance between adjacent levels in lumbar spine in a normal population. Two hundred normal AP radiographs of non-injured thoracolumbar spine were studied. The interspinal process distance was measured as the distance between the cranial ends of the adjacent projections of spinous processes on AP radiographs. The mean values and 99% confidence limits for changes in the interspinal process distances between adjacent spinal levels were determined and analysed in relation to age, gender and spinal segment level. An upper limit of a normal difference in distance between the spinous processes at two adjacent levels was determined to be 7-10 mm, depending on age and location in the lumbar spine. A difference in interspinal process distance exceeding 7 mm between two adjacent lumbar levels should alert a surgeon to severe and unstable injury.

Combination of blood-saving methods decreases homologous blood requirements in scoliosis surgery.

A study was conducted in patients undergoing surgery for idiopathic scoliosis, to determine whether combining blood-saving methods would decrease the need for homologous blood. Five groups were compared in a prospective, randomized fashion. In control patients (n = 13), blood loss was replaced by colloids. Preoperative haemodilution (PHD group) was used in ten patients. In the intraoperative autotransfusion (IAT) group (n = 11), washed red cells were returned to the patient. In the PHD+IAT group, both methods were combined (n = 13). In the fifth group, in addition, arterial hypotension was maintained with sodium nitroprusside (the PHD+IAT+HA group, n = 10). The haemoglobin value was kept above 79 g/l. Total blood loss did not differ between groups. The use of homologous blood in the PHD+IAT and PHD+IAT+HA groups was significantly less than in controls. It is concluded that blood-saving measures can be combined with an augmentative effect.

Flexion-distraction injury of the lumbar spine: influence of load, loading rate, and vertebral mineral content.

The biomechanical response of the lumbar spine to combined flexion-shear loading was determined experimentally. The injury model simulated flexion-distraction trauma to the lumbar spine. Forty-eight lumbar functional spinal units (FSUs) were subjected to dynamic loading to injury with six different load types. The reactive forces and moments and resulting deformity were determined. Static physiologic loading was performed before and after the injurious loading to assess residual injury. The biomechanical response of FSUs was dependent on the amount of load and loading rate. The vertebral bone mineral content explained most of the biologic variation of the results. An osteoporotic or severely degenerated spine will be more easily rendered unstable after trauma with lower deformity. Injury at high loading rates will create instability with lower deformity. In vitro experiments should be performed on entire spinal units and with combined loads.

Traumatic instability of the lumbar spine. A dynamic in vitro study of flexion-distraction injury.

STUDY DESIGN: This in vitro study determined the effect on the lumbar spine of a dynamic flexion-distraction loading simulating a lap seatbelt injury. The proportion by which the forces and the moments contributed to the injury of the lumbar spinal segment in such a situation was analyzed. The remaining stability of the injured lumbar motion segment was determined together with the threshold for lumbar spine instability in such an injury. OBJECTIVES: Based on the experimental results in this study, radiographic guidelines for instability criteria in lumbar and thoracolumbar dislocations in the sagittal plane without concomitant compression fracture of the middle column were proposed. SUMMARY OF BACKGROUND DATA: A number of check-lists and guidelines were suggested for the diagnosis of spinal instability after trauma, but no conclusive system was established. Those systems were mostly based on experiments performed on spinal segments after sequential ablation of ligaments and facet joints followed by static, unidirectional physiologic loading. We believed that there was a need for more profound knowledge of spinal injury and for instability criteria of lumbar spinal injuries based on more realistic experimental data simulating the clinical situation. In our injury model, we decided to study the biomechanic outcome of a flexion-distraction injury similar to seatbelt type injury seen in frontal motor vehicle collisions. METHODS: Twenty lumbar functional spinal units were first loaded statically with a physiologic flexion-shear load to determine angulations and displacements under noninjurous conditions. Dynamic flexion-shear loading to injury with two different load pulses was then applied. Static physiologic load was then again applied to determine any permanent residual deformation. RESULTS: The viscoelastic effect of loading rate on translatory and angular displacements and the values for translatory and angulation displacements at first sign of injury (yield) and at failure were determined. CONCLUSIONS: Radiographic guidelines for instability criteria in lumbar and thoracolumbar fracture-dislocations without concomitant posterior vertebral body compression are proposed: 1. Instability exists if there is a kyphosis of the lumbar motion segment > or = 12 degrees (impending instability) or > or = 19 degrees (total instability) on lateral radiographs. 2. Relative increase in interspinous process distance > or = 20 mm (impending instability), > or = 33 mm (total instability) on anteroposterior radiographs.

Progression of scoliosis in children with myelomeningocele.

In a retrospective follow-up of 64 patients with myelomeningocele and scoliosis of more than 10 degrees, the development of the scoliosis curve was watched. The mean follow-up was 4.3 years. Most progression of scoliosis can be expected before 15 years of age. Fifty-four percent of the patients with scoliosis of 40 degrees or more progressed more than 5 degrees per year. Progression was dependent on the scoliosis angle. A multivariate model for the prediction of the scoliosis progress in a 1-year perspective was applied. The model included the current scoliosis angle, the age of the patient, the skeletal level of the dysraphism, and the patient's ambulation capacity.

Brace treatment of scoliosis in children with myelomeningocele.

In twenty-one children with myelomeningocele and progressive scoliosis, treatment of scoliosis was attempted with a Boston type underarm brace. Thirteen children finished full brace treatment (average treatment time 2.5 years) and the patients were included in a follow-up more than 2 years after the end of treatment with no further progression of the scoliosis. Two patients are still undergoing brace treatment. Six children were operated due to continued progression of the scoliosis. Among 14 patients with scoliosis 45 degrees or less at the start of brace treatment, only 1 patient progressed and underwent operation. The brace had a temporary effect on severe scoliosis, decreasing the rate of progression. Complications were few. The brace caused decubitus ulcer in one patient, and two patients developed increased pressure of the urinary tract.

A method for studying the biomechanical load response of the (in vitro) lumbar spine under dynamic flexion-shear loads.

A method was developed to study the biomechanical response of the lumbar motion segment (Functional Spinal Unit, FSU) under a dynamic (transient) load in flexion. In order to inflict flexion-distraction types of injuries (lap seat-belt injuries) different load pulses were transferred to the specimen by means of a padded pendulum. The load response of the specimen was measured with a force and moment transducer. The flexion angulation and displacements were determined by means of high-speed photography. Two series of tests were made with ten specimens in each and with two different load pulses: one moderate load pulse (peak acceleration 5 g, rise time 30 ms, duration 150 ms) and one severe load pulse (peak acceleration 12 g, rise time 15 ms, duration 250 ms). The results showed that the moderate load pulse caused residual permanent deformations at a mean bending moment of 140 Nm and a mean shear force of 430 N at a mean flexion angulation of 14 degrees. The severe load pulse caused evident signs of failure of the segments at a mean bending moment of 185 Nm and a mean shear force of 600 N at a mean flexion angulation of 19 degrees. Significant correlations were found between the load response and the size of the specimen, as well as between the load response and the bone mineral content (BMC) in the two adjacent vertebrae. Comparisons with lumbar spine response to static flexion-shear loading indicated that the specimens could withstand higher bending moments before injury occurred during dynamic loading, but the deformations at injury tended to be smaller for dynamic loading.

The ultimate flexural strength of the lumbar spine and vertebral bone mineral content.

Flexion-distraction injuries (lap seat-belt injuries resulting from car accidents) were simulated by exposing 16 lumbar functional spinal units (FSUs) to a combined quasistatic load of bending and shearing in the sagittal plane. The load response of the FSU was measured by means of a force and moment transducer. Displacements and angulations were measured and calculated by means of dial gauges and photographs taken after each loading step. The mean angulation between the vertebrae just before total rupture was 20 degrees. The ultimate values of bending moment, shear force, and bending stiffness were correlated with the bone mineral content (BMC), and so were the horizontal and vertical displacements determined around the yield point on the load-displacement curve.

The influence of scoliosis brace treatment on function in children with myelomeningocele.

The influence of Boston brace treatment on the functional and motor ability of children with scoliosis secondary to myelomeningocele was studied in a consecutive series of 20 children of 5-19 years of age. Motor activity, ADL function and ambulation ability were assessed before brace treatment and then annually during the treatment period, which lasted an average of 2.7 years (range 0.6-8.7 years). Thirteen children were followed-up one year after braces were removed. The effect of brace treatment on the scoliosis was favourable as is reported elsewhere. The children's motor activity and ADL function remained unchanged during brace treatment, but brace wearing was accompanied by a decreased ambulatory skill. This may partly be explained by a slight increase of flexion contractures of the hips during treatment. Patients with useful ambulation ability kept this ability up even during brace treatment. Considering the favourable effect of brace treatment on the scoliosis curve and the few complications encountered, we recommend brace treatment for scoliosis in patients with myelomeningocele.

The mechanism of initial flexion-distraction injury in the lumbar spine.

The threshold for flexion-distraction injuries was determined on lumbar functional spinal units exposed to a combined flexion-shear load in the sagittal plane. The specimens could resist a bending moment of 121 Nm and a shear force of 486 N at the first sign of a permanent deformation of the osteoligamentous components, which occurred at 78% of the assumed ultimate strength of each specimen. The flexion angulation was 16 degrees. The bone mineral content determined in adjacent vertebrae by means of dual photon absorptiometry was an accurate predictor of structural properties of the entire functional spinal unit even at the first sign of a substantial structural injury and not only at ultimate failure as previously demonstrated.

Prevalence of scoliosis in children with myelomeningocele in western Sweden.

In a cross-sectional study of the prevalence of scoliosis in patients with myelomeningocele, 131 patients 5-20 years of age were investigated with clinical examination and radiograms. Sixty-nine percent of the myelomeningocele patients had scoliosis, this prevalence being present already at a young age (6 years). The occurrence of scoliosis increased drastically at high levels of dysraphism, being 20% in patients with sacral myelomeningocele but 94% in patients with thoracic MMC level. Between ages 5 and 10, the mean scoliosis increased successively from 15 to 33 degrees. After this age there was no significant further increase. The ambulatory status of the patients was strongly correlated to the scoliosis incidence. Forty-nine percent of the patients had a uni- or bilateral hip dislocation. There was no correlation between the side of the scoliosis convexity and the side of hip dislocation.

Influence of surgical treatment of scoliosis in children with spina bifida on ambulation and motoric skills.

The influence on motoric skills of surgical treatment of scoliosis in 14 children with myelomeningocele was studied. Fifty percent of the children had increased flexion contractures of the hips at follow-up, and all but one patient had impaired motor ability. There was no influence on activities of daily life, but 57% of children had lost some of their ambulation capacity. Postoperative physiotherapy is highly advisable. Intensive attempts to treat these children conservatively to prevent scoliosis progression is suggested.

Thoracotomy and scoliosis.

The incidence of thoracic scoliosis after completion of growth was studied in a group of patients operated on in childhood with a lateral thoracotomy for esophageal atresia and cardiac and pulmonary disorders. Twenty of 61 patients had a thoracic scoliosis exceeding 10 degrees. The curves were mostly convex toward the operated side except in patients treated surgically for esophageal atresia, in which they were concave toward the operated side. None of the curves exceeded 25 degrees, and no therapy was needed. Thoracic scoliosis should, however, be remembered as a possible complication after lateral thoracotomy in childhood.