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.

Neurobehavioral and developmental profile of very low birthweight preterm infants in early infancy

AIM

To describe the neurobehavioral and developmental profile of very low birthweight (VLBW) preterm infants in early infancy.

METHODS

Twenty VLBW infants and 10 term control infants were assessed at term, 3 and 6 mo of age. Neurobehavioral assessments included the Neonatal Behavioral Assessment Scale (NBAS) at term; the Infant Behavioral Assessment at term, 3 and 6 mo of age and the Behavioral Rating Scale of the Bayley Scales of Infant Development-II (BSID-II) at 3 and 6 mo of age. Development was evaluated with the Bayley Motor and Mental Scale at 3 and 6 mo.

RESULTS

At term age VLBW infants differed from term infants on all the clusters and supplementary items of the NBAS. VLBW infants also showed more stress and less approach behavior at term and 6 mo of age and more problems with self-regulation in all subsystems at 6 mo of age. Moreover, VLBW infants performed lower on the Bayley Motor, Mental and Behavioral Rating Scale: 12 VLBW infants scored questionable or non-optimal on the Psychomotor Development Index and 18 questionable or non-optimal on the Behavioral Rating Scale. These results support the need for neurobehavioral intervention of VLBW infants in the first 6 mo of life.

CONCLUSION

Almost all VLBW infants showed non-optimal motor quality behavior at 6 mo and encountered far more problems with self-regulation compared with term infants.

Intra- and inter-tester reliability and reference values for isometric neck strength

BACKGROUND AND PURPOSE

Age- and sex-specific reference values for neck strength based on reliable measurements in the upright position are lacking. The aim of the present study was to determine intra- and inter-tester reliability and age- and sex-specific reference values for isometric neck strength in extension, flexion and lateral flexion in sitting position measured with the David Back Clinic 140 (DBC 140) equipment.

METHOD

The reliability of the DBC 140 equipment was investigated in 30 healthy volunteers and reference values were obtained from 101 healthy men and women.

RESULTS

The reliability study showed that neck strength measured with the DBC 140 equipment has almost perfect intra- and inter-tester reliability (ICC values between 0.85 and 0.97). The mean value of the first in a series of three measurements was the highest for all three test leaders and for almost all directions. Results from the reference value study showed that gender is a much more important determinant of neck strength than age, body weight or body mass index (BMI). Neck strength in women was, on average, 55% of that in men, and when adjusted for body weight or BMI, the percentages were 70% and 59%, respectively. In all directions observed, neck strength decreased by approximately 20% from age 25 to 64 years.

CONCLUSIONS

Measurements of neck strength taken in upright position with the DBC 140 equipment have almost perfect intra- and inter-tester reliability and justify the use of this test procedure. The use of the first measurement in a test series can be recommended for use in clinical practice since it was shown to be the maximal test value and thus, had a very low intra-tester difference. The use of reference values for neck strength when evaluating patients with neck disorders needs to take gender into account.

Laminar hook instrumentation in the cervical spine. An experimental study on the relation of hooks to the spinal cord

Several anterior and posterior methods are today available for stabilization of the cervical spine. Factors such as level and degree of instability, method of decompression, bone quality, length of fixation and safety factors influence the choice of method for a particular patient. The use of laminar hooks in the cervical spine has been restricted by fear of cord compression with the potential of tetraplegia. The aim of the present study was to assess the safety and determine the anatomical relation between hooks inserted in the cervical spinal canal and the dura and spinal cord. Thirteen cadavers from seven women and six men with no evidence of cervical spine disorder were included. The mean age was 81.3 years (range 65-101 years). The cervical spine was instrumented with cervical Compact Cotrel Dubousset hooks and rods. The effect of the hook on the dura was studied by myelography in nine cadavers. The deformation of the dural sac was quantified by measurement of the maximal width of the indentation of the contrast column at each level. A CT myelography scan was obtained in three cadavers. The ratio between the distance of maximal hook intrusion into the spinal canal and the canal diameter in the direction of the hook was calculated. The relation between inserted hooks and the spinal cord and dura was documented in a fresh cadaver studied with CT myelography. A hemilaminectomy was performed at all levels in three cadavers with direct visual inspection and photography of the hook sites before and after excision of the dura. A dural deformation of 2 mm or less, as observed by myelography, was found at four out of 77 (5%) hook sites. The deformation was caused by a supralaminar hook at C3, C6 and C7 and by an infralaminar hook at C6. The mean hook intrusion in the spinal canal, as observed on CT, was 27% (range 8-43) of the canal diameter. On visual inspection, 14 out of 18 hooks were in contact with the dura. After removal of the dura, two out of the 18 hooks in the same cadaver were in contact with the spinal cord. However, no deformation of the cord was observed. To our knowledge this is the first study systematically documenting the relation between hooks and the spinal cord in cadavers. In 95% of the hooks no deformation of the dural sac was observed and there was no evidence of spinal cord deformation. From an anatomical point of view, laminar hook instrumentation can be considered a safe procedure. The study shows, however, that hooks inserted in the cervical spine have a close anatomical relationship with the neuraxis, and at stenotic levels the use of other techniques is therefore recommended.

Intra- and inter-tester reliability and reference values for hand strength

The intra- and inter-tester reliability for measurement of handgrip strength and indexgrip strength using the Jamar dynamometer was investigated in 32 healthy volunteers, and the intra-tester reliability in 13 patients with cervical radiculopathy. The results from the reliability studies showed that handgrip and indexgrip strength measured with the Jamar dynamometer is a reliable method (ICC values 0.85-0.98) and can be recommended for use in clinical practice. Age- and sex-specific reference values for handgrip strength and indexgrip strength were measured with the Jamar dynamometer in 101 randomly selected healthy volunteers, aged 25-64 years. The results from the reference value study showed that sex is a more important determinant of hand strength than age, height and body weight. The reference values for hand strength improve the potential for objective evaluation of patients with arm/hand disorders caused by cervical radiculopathy.

Instrumented and noninstrumented posterolateral fusion in adult spondylolisthesis--a prospective randomized study: part 2

STUDY DESIGN

A prospective randomized study was performed.

OBJECTIVE

To determine whether transpedicular fixation improves the outcome of posterolateral fusion in patients with adult isthmic spondylolisthesis.

SUMMARY OF BACKGROUND DATA

The use of transpedicular fixation remains controversial. Both a positive effect and no effect from additional transpedicular fixation have been reported.

METHODS

In this study, 77 patients randomly underwent posterolateral fusion with (n = 37) or without (n = 40) transpedicular fixation. The inclusion criteria were lumbar isthmic spondylolisthesis of any grade, at least 1 year of low back pain or sciatica, and severely restricted functional ability in individuals 18 to 55 years of age.

RESULTS

The follow-up rate was 94%. At a 2-year follow-up assessment, the level of pain and functional disability were strikingly similar in the two groups, and there was no significant difference in fusion rate.

CONCLUSIONS

Lumbar posterolateral fusion performed in situ for adult isthmic spondylolisthesis relieves pain and improves function. The use of supplementary transpedicular instrumentation does not add to the fusion rate or improve the clinical outcome.

Surgery versus conservative management in adult isthmic spondylolisthesis--a prospective randomized study: part 1

STUDY DESIGN

A prospective randomized study was performed.

OBJECTIVE

To determine whether posterolateral fusion in patients with adult isthmic spondylolisthesis results in an improved outcome compared with an exercise program.

SUMMARY OF BACKGROUND DATA

In spondylolisthesis, satisfactory results have been reported with both surgical and conservative management. The evidence for treatment efficacy, however, is weak because prospective randomized studies are lacking.

METHODS

In this study, 111 patients were randomly allocated to an exercise program (n = 34) or posterolateral fusion with or without transpedicular fixation (n = 77). The inclusion criteria were lumbar isthmic spondylolisthesis of any grade, at least 1 year of low back pain or sciatica, and a severely restricted functional ability in individuals 18 to 55 years of age. Pain and functional disability were quantified before treatment and at 1- and 2-year follow-up assessments by visual analog scales (VAS).

RESULTS

The 2-year follow-up rate was 93%. The functional outcome, as assessed by the Disability Rating Index and the pain reduction, was better in the surgically treated group than in the exercise group at both the 1- and 2-year follow-up assessments (P < 0.01). In the longitudinal analysis, the mean Disability Rating Index and pain improved in the surgical group (P < 0.0001). In the exercise group, the Disability Rating Index did not change at all, whereas the pain decreased slightly (P < 0.02).

CONCLUSIONS

Surgical management of adult isthmic spondylolisthesis improves function and relieves pain more efficiently than an exercise program.

Symptoms, signs, and functional disability in adult spondylolisthesis

STUDY DESIGN

A cross-sectional clinical study.

OBJECTIVES

To determine whether there are specific symptoms, signs, and functional disability associated with adult spondylolisthesis.

SUMMARY OF BACKGROUND DATA

In spite of the common occurrence of adult spondylolisthesis, the symptoms, signs, and disability associated with it have not been analyzed in a large, well-defined group of patients.

METHODS

The symptoms, signs, and disability of 111 consecutive patients with adult spondylolisthesis, before randomized treatment with fusion or physiotherapy, were compared with those of 39 patients with nonspecific low back pain before lumbar fusion. The patients completed a questionnaire covering clinical history and symptoms and submitted a pain drawing. The signs were documented. Functional disability and pain were quantified by 12-function and 2-pain visual analog scales, respectively.

RESULTS

Sixty-two percent of the patients reported low back pain as well as sciatica, 7% sciatica only, and 31% low back pain only. Specific signs were infrequent. A positive straight leg raising test result in 12% and an L5 sensory disturbance in 13% were the most common. The symptoms were similar in patients with spondylolisthesis and chronic low back pain, but the chronic low back pain group reported more functional disability. Patients with a nonorganic pain drawing (widespread, nonspecific pain) were more often blue collar workers; were more often and longer on sick leave; and reported reduced mental condition, sexual function, functional ability, and more pain than patients with an organic pain drawing (localized, specific pain).

CONCLUSIONS

The clinical pattern and functional disability in adult spondylolisthesis and in low back pain of nonspecific origin are similar. Sciatica in adult spondylolisthesis is typically not associated with a positive straight leg raising test result.

The segmental effect of Cotrel-Dubousset instrumentation on vertebral rotation, rib hump and the thoracic cage in idiopathic scoliosis

The segmental effect of Cotrel-Dubousset instrumentation (CDI) on the spine and thoracic cage was investigated in 38 patients with adolescent idiopathic scoliosis by preoperative and postoperative postero-anterior and lateral radiographs and computed tomography from T1 to S1. Mean Cobb angle decreased by 67%. The T5-T12 kyphosis in the hypokyphotic patients increased on average by 8.4 degrees (P < 0.001). Average preoperative as well as postoperative maximal vertebral rotation was located at the apex level, and was reduced from 19.0 degrees to 14.3 degrees (P < 0.001). All vertebrae between the upper and lower instrumented vertebrae were significantly derotated. Average derotation for the apical zone was 4.8 degrees (P < 0.001), for the upper instrumented zone it was 2.5 degrees (P < 0.01), and for the lower instrumented zone it was 2.6 degrees (P < 0.01). Vertebral derotation was significantly higher in the apical zone than in the upper and lower instrumented zones. The apical rib hump index (RHi) decreased by 38% (P < 0.001) and the cumulative RHi for the five apical levels decreased by 34% (P < 0.001). The RHi for the two levels above and below the instrumentation each decreased by 20% (n.s.). No significant increase in sagittal or transverse rib cage diameter at any level was observed. The translation in the coronal plane of the apical vertebra of major right thoracic curves improved significantly (P < 0.001). The preoperative flexibility index of the major curve correlated positively (r = 0.47) with derotation at the apex level (P < 0.01). However, no correlation was found between flexibility index and reduction of RHi at the apex level. Vertebral derotation did not correlate with reduction in RHi at any level. The study shows that CDI results in a postoperative three-dimensional improvement of the spine and a limited improvement of the thoracic cage, with no tendency towards a worsened deformity at any level within or outside the instrumentation.

Degenerative changes following anterior cervical discectomy and fusion evaluated by fast spin-echo MR imaging

PURPOSE

To review pre- and postoperative fast spin-echo (FSE) MR images of disc herniation and spondylosis in patients after spinal cervical surgery.

MATERIAL AND METHODS

Data were reviewed of 68 patients after anterior discectomy and fusion (ADF) operations using the Cloward technique with solid single level (C5-C6 or C6-C7) or 2-level fusions (C5-C7). The average interval from surgery to review was 37 months. Age- and sex-matched controls without neck problems were examined.

RESULTS

Preoperatively, the fusion groups had a higher incidence of protruded disc, and anterior and posterior osteophytes at the levels to be fused than the controls. Post-operatively, there was a significantly higher incidence of posterior osteophytes at the fused levels compared with the controls. Furthermore, the disc herniations and anterior osteophytes at the levels above and below the operated segments were more frequent in the fusion group.

CONCLUSION

ADF causes acceleration of the degenerative changes at the fused level and at the levels below and above the fused segments.

Fast spin-echo MR assessment of patients with poor outcome following spinal cervical surgery

PURPOSE

The aim of the investigation was to evaluate poor outcome following spinal and cervical surgery.

MATERIAL AND METHODS

A total of 146 consecutive patients operated with anterior discectomy and fusion (ADF) with the Cloward technique were investigated. Clinical notes, plain radiography, CT, and fast spin-echo (FSE) images were retrospectively evaluated.

RESULTS

Some 30% of the patients had unsatisfactory clinical results within 12 months after surgery; 13% had initial improvement followed by deterioration of the preoperative symptoms, while 14.4% were not improved or worsened. Disc herniation and bony stenosis above, below, or at the fused level were the most common findings. In 45% of patients, surgery failed to decompress the spinal canal. In only 4 patients was no cause of remaining myelopathy and/or radiculopathy found. FSE demonstrated a large variety of pathological findings in the patients with poor clinical outcome after ADF. Postoperatively, patients with good clinical outcome had a lower incidence of pathological changes.

CONCLUSION

FSE is considered the primary imaging modality for the cervical spine. However, CT is a useful complement in the axial projection to visualize bone changes.

The position of the aorta in relation to the vertebra in patients with idiopathic thoracic scoliosis

One CT-scan at the central part of the vertebral body of the apical vertebra of 32 patients with right convex thoracic idiopathic scoliosis and one CT-scan of either T8 or T9 of 22 normal subjects are included in this study. The position of the aorta in relation to the apical vertebra of the scoliotic patients and the corresponding vertebra of the normal subjects was determined at the horizontal plane. The mean lateral translation of the aorta in relation to the mid axis of the vertebral body increased from 19.7 +/- 4.3 mm in the normal group to 26.4 +/- 4.1 mm in the scoliotic group (p = 0.0001). In the normal group the aorta was located 41.7 +/- 8.6 mm in front of a perpendicular line to the mid axis of the vertebral body and in the scoliotic group this distance was reduced to 30.0 +/- 9.0 mm making the position of the aorta more posterior in the scoliotic group (p = 0.0001). This was in accordance with a decreased mean kyphosis-lordosis index from 0.53 +/- 0.06 in the normal group to 0.46 +/- 0.07 in the scoliotic group (p = 0.01). The position of the aorta, also expressed as the angle formed between the aorta and the vertebral body, the "aorto-vertebral angle", was increased from 24.4 degrees +/- 6.9 degrees in the normal group to 41.4 degrees +/- 8.4 degrees the scoliotic patients, (p = 0.0001). The aorto-vertebral angle did not change significantly with increasing Cobb angle (p = 0.26) but was positively correlated to the vertebral rotation (p = 0.0001). An estimation of the length of the intercostal arteries revealed a significantly greater R (right)/L (left) index in the scoliotic patients 1.18 +/- 0.11 than in the normal subjects 1.08 +/- 0.06 (p = 0.0003). It is concluded that the rotation and the anterior displacement of the vertebral body in scoliosis result in a deviation of the aorta along the left (concave) side of the vertebral body to a more posterior position relative to the vertebral body with a possible increased length of the intercostal artery on the right (convex) side.

Electrical muscle stimulation on the spine. Three-dimensional effects in rabbits

We investigated the 3-dimensional effect of electrostimulation of the latissimus dorsi, the erector spinae and the intercostal muscles on spinal configuration in 16 New Zealand white rabbits. Electrostimulation on the right side of the spine resulted in a left convex, hypokyphotic curve and vertebral body rotation towards the convexity of the curve in all rabbits. The Cobb angle in the coronal plane increased with stimulation of each of the muscles examined. The kyphosis decreased with stimulation of the latissimus dorsi and the erector spinae. The vertebral rotation increased with stimulation of all muscles. Stimulation of the tested muscles resulted in the simultaneous occurrence of a 3-dimensional spinal deformity with the characteristics of idiopathic scoliosis.

Accuracy and applicability of measurement of the scoliotic angle at the frontal plane by Cobb's method, by Ferguson's method and by a new method

A new method for the measurement of scoliotic curves in antero-posterior (AP) radiographs is presented, in which the centre of the surface image of the vertebral bodies of the apical and two end vertebrae of the curvature are defined on the basis of geometric principles. Measurements using the Cobb, the Ferguson, and the new method were performed on ten AP radiographs from each of three groups of young patients with right convex thoracic idiopathic scoliosis with Cobb angles of between 7 and 15 degrees, 16 and 45 degrees and 46 and 80 degrees, respectively. Measurements using the Cobb method yielded significantly higher values than measurements using either the Ferguson method or the new method. In curves with Cobb angles of between 7 and 15 degrees, the values using Ferguson's method were significantly lower than those using the new method; the difference increased significantly in curves with a Cobb angle of 16 degrees or more. The level of significance of the intra- and interobserver differences between the new, the Cobb and the Ferguson methods was significantly higher in curves with a Cobb angle of 16 degrees or more. It is argued that measures of the scoliotic angle obtained by the new method are of greater clinical relevance than those obtained by the two other methods. Unlike the Cobb method, the new method takes into consideration the translation of the apical vertebra in relation to the end vertebrae and not only the tilt of the end vertebrae of the curve. As compared to the Ferguson method, the new method is based on standardised geometric principles, and is not influenced by changes in the shape of the vertebral body. Moreover, the repeatability of the new method is greater than that of both the Cobb method and the Ferguson method. Therefore, it is believed that the new method provides a more accurate measure of the scoliotic curve than do the two other methods, and it is to be preferred over the other two methods in longitudinal evaluation of the development of the curve.

Vertebral rotation and pedicle length asymmetry in the normal adult spine

Rotation in the horizontal plane of vertebra T8, T9 or T10 was determined on CT scans of 25 male and 25 female patients with normal spines. The pedicle length was measured using a new method, and the right/left pedicle length index was calculated. In 38 (76%) of the patients there was vertebral rotation to the right with a mean Cobb angle of 3.0 degrees, and in 4 (8%) rotation to the left, mean Cobb angle 2.2 degrees (P < 0.01). In 8 (16%) there was no measurable rotation. The pedicle length index was greater than 1.05 in 9 subjects, between 0.95 and 1.05 in 16 and less than 0.95 in 25, indicating a predominance of longer pedicles on the left side. In 21 out of the 38 patients with vertebral rotation to the right, the left pedicle was longer than the right one (P < 0.01). The results indicate that the normal spine is afflicted with a vertebral rotation to the right in association with a longer pedicle on the left. The significance of these observations for the pathogenesis of idiopathic scoliosis remain uncertain.

Structural vertebral changes in the horizontal plane in idiopathic scoliosis and the long-term corrective effect of spine instrumentation

The rotation and structural changes of the apex vertebra in the horizontal plane as well as of the thoracic cage deformity were quantified by measurements on computed tomography (CT) scans from patients with right convex thoracic idiopathic scoliosis (IS). The CT scans were obtained from 12 patients with moderate scoliosis (mean Cobb angle 25.8 degrees, r 13 degrees-30 degrees) and from 33 with severe scoliosis (mean Cobb angle 46.2 degrees, r 35 degrees-71 degrees). In addition, CT scans of thoracic vertebrae from 15 patients without scoliosis were used as reference material. Ten of the scoliotic cases had had Cotrel-Dubousset instrumentation (CDI) and posterior fusion and had entered a longitudinal study on the effect of operative correction on the re-modelling of the apical vertebra. An increasingly asymmetrical vertebral body, transverse process angle, pedicle width and canal width were found in the groups with scoliosis as compared with the reference material. Vertebral rotation and rib hump index were significantly larger in patients with early and advanced scoliosis than in normal subjects. The modelling angle of the vertebral body, the transverse process angle index and the vertebral rotation in relation to the middle axis of the thoracic cage were significantly greater in patients with severe than with moderate scoliosis. The results of this longitudinal study suggest that the structural changes of the apical vertebra regress 2 years or more after CD instrumentation.

Horizontal plane morphometry of normal and scoliotic vertebrae. A methodological study

Computed tomography (CT) scans are widely used for quantification of the morphology of the vertebral body and of the changes of the thoracic cage in the horizontal plane in scoliosis. So far, however, no method exists for precise quantification of the parameters of the posterior elements. We present a method for quantification on the basis of CT scans of different parameters of the morphology of both the vertebral body and posterior elements in the horizontal plane. The precision and accuracy of the method were estimated in a model study by CT scanning of a normal and a scoliotic vertebra in different, controlled, tilted positions. Moreover, in a clinical study CT scans of 19 thoracic vertebrae from non-scoliotic subjects and the apex vertebra from 40 scoliotic subjects were selected to test the applicability of the method to clinical studies. The intra- and interobserver variation of the measurements was analysed. The angle between the longitudinal axis of the vertebral body and that of the whole vertebra was used to evaluate the asymmetry of the vertebral body. The right to left pedicle width index, the right to left hemi-canal width index and the index of transverse process angles related to the axis of the vertebra were used to quantify the asymmetry of the posterior elements. The results indicate that, except for the pedicle width index, the variables under study were not significantly influenced by a 5 degrees or 10 degrees tilt ventrally, dorsally, or laterally of either the normal or the scoliotic vertebra. Hence, the method can be satisfactorily applied to longitudinal group comparisons.(ABSTRACT TRUNCATED AT 250 WORDS)

Radiographic changes at the coronal plane in early scoliosis

The development of structural skeletal changes was evaluated on 132 anteroposterior radiographs of spines from three scoliotic groups with a Cobb angle of up to 30 degrees and a reference control group. Significant wedging of the vertebral bodies and disks at the coronal plane was registered in-curves with a Cobb angle of 4 degrees or more. Asymmetry of the rib-vertebra angle was found in curves with a Cobb angle of 8 degrees or more and was most pronounced in the cranial part of the curves. The early simultaneous occurrence of vertebral and disk wedging suggests the involvement of an extraspinal factor rather than growth disturbance of the vertebral body or of the disk in the early pathomechanism of scoliosis.

Sagittal configuration of the spine and growth of the posterior elements in early scoliosis

The early changes of the sagittal alignment of the spine and the asymmetry between the posterior and anterior elements were determined on the basis of 134 lateral and 167 anteroposterior radiographs obtained from a control group and from patients with early scoliosis. The radiographs were allocated into four groups according to the degree of the Cobb angle. In thoracic curves with a Cobb angle of more than 8 degrees, the kyphosis and the vertebral sagittal wedge angle decreased in comparison with the control group. The sagittal-wedge angle of the disc did not change significantly with increasing Cobb angle. The pedicle height in relation to the vertebral height, considered to represent the growth of the posterior element in relation to the growth of the anterior element, was not significantly different in the scoliotic groups as compared with the control group. The results indicate that changes of the sagittal configuration of the spine occur early in idiopathic scoliosis and that they are associated with disturbed growth of the vertebral body but not of the posterior elements. These findings seem to reflect a simultaneous deformation in the coronal and sagittal planes rather than a single growth disturbance in any specific plane.

Long-term results of Harrington instrumentation in idiopathic scoliosis

The long-term effect of Harrington instrumentation was investigated using posteroanterior radiographs and computed tomographic measurements preoperatively, postoperatively, and at a mean follow-up at 10.8 years in 33 patients with idiopathic scoliosis. No patient was lost from long-term follow-up. At follow-up, the mean Cobb angle was improved by 23.7 (40%) compared with the preoperative findings. The rotation of the apical vertebra was increased significantly. The rib hump, the translation of the apical vertebra, and the sagittal diameter of the thoracic cage were unchanged. At follow-up, the mean thoracic kyphosis was 17.3, and lumbar lordosis was 22.0. This study demonstrated that the long-term effect of Harrington instrumentation was limited to an improved Cobb angle; no correction of the rotational or sagittal deformities were achieved.

Long-term results of Boston brace treatment on vertebral rotation in idiopathic scoliosis

The long-term effect of Boston brace treatment was investigated by computed tomography measurements before treatment, after bracing, and at mean follow-up at 8.5 years in 25 patients with idiopathic scoliosis. At follow-up, the pretreatment Cobb angle, the vertebral rotation, the rib hump, and the translation of the apical vertebra were not significantly changed. The sagittal diameter of the thoracic cage was significantly decreased at follow-up. The current study demonstrates that the Boston brace does not improve, but prevents progression of vertebral rotation, translation, rib hump, and Cobb angle in idiopathic scoliosis. The reduced sagittal diameter is noteworthy and may be of importance for cosmesis and pulmonary function.

Age- and sex-specific incidence of femoral neck and trochanteric fractures. An analysis based on 20,538 fractures in Stockholm County, Sweden, 1972-1981

The risk of fracturing the proximal femur is high for individuals with metabolic bone disease or with low bone mass associated with advanced age. Incidences of 20,538 trochanteric and femoral neck fractures in adult Swedish men and women, from a computerized medical information register for all hospitals in Stockholm County, were analyzed for age- and sex-dependence. The rate of increase in the occurrence of fracture was nearly constant for both sexes, exponentially increasing with age for men over 20 years old and for women over 30 years old. The incidence of trochanteric and femoral neck fracture for men doubled every 7.8 and 7.0 years, respectively. The doubling rate of fracture incidence for premenopausal women, aged 30 to 49 years, did not significantly differ from that for postmenopausal women, aged 50 to 69 years. These findings suggest that age-associated factors common to both sexes provide the main risk for fracturing the proximal femur. Menopause does not pose a major risk.

Trauma type, age, and gender as determinants of hip fracture

We determined the trauma type of femoral neck and trochanteric fractures in men and women aged greater than or equal to 20 years in 19, 128 fractures reported to a computerized medical information register during 1972-1981. We found that the earlier known exponential increase of fracture incidence by age started in early adulthood rather than during middle age. An age-related increase was found for each type of injury as well, although the incidence of fractures resulting from severe trauma increased less than that of fractures associated with moderate trauma. The incidence of low-energy fractures in men as well as in women displayed a constant increase rate with age from young adulthood on, impugning the widely held belief that the menopause is a significant risk factor for fractures. The dominating risk factor for proximal femoral fracture in adults appears to be age, irrespective of the cause of injury, with a chronological decline in bone strength as the most likely cause of the exponential increase in the fracture incidence during adult life.

Epidemiology of diaphyseal femoral fracture

The incidence of diaphyseal femoral fracture in adults, aged 20 years and older, was determined in Stockholm County using hospital admission rates. The validity of the data was investigated by a study of the medical records of a sample of 277 cases and also by determining the incidence in a subpopulation of 139 cases using an alternative method. The incidence decreased from age 20 to middle age after which it increased into old age. The age-related increase was more pronounced in women and in fractures caused by moderate trauma. From 1972 to 1981, the incidence of diaphyseal femoral fracture caused by moderate trauma increased annually by 10 per cent in women aged 75 years and older.

Hip fracture incidence in Stockholm 1972-1981

We studied the incidence of cervical and trochanteric hip fractures in Stockholm, Sweden from 1972 through 1981. The material, selected from a computerized medical information register, consisted of 11 812 cervical fractures and 8094 trochanteric fractures. The incidence did not change in the age group 50-74 years. In males 75 years of age and older, the incidence of both fracture types caused by moderate trauma increased annually by 5-6 per cent. In females 75 years and older, the incidence of trochanteric fractures caused by moderate trauma increased annually by 6 per cent, whereas the incidence of cervical fractures increased only marginally.

The incidence of femoral shaft fractures in children and adolescents

We report the incidence of fractures by sex and age based on 851 femoral shaft fractures from specific types of trauma. The maximum incidence occurred between 2 and 3 years of age, and the total incidence was 2.6 times higher in boys than in girls. In 438 cases the fractures were caused by falls and in 413 cases by traffic accidents. Fractures reported to be caused by falls were most common in children 2 and 3 years of age. Because child abuse has been shown to be involved in the majority of such fractures in early infancy, the data demonstrate the possible magnitude of this problem. Traffic accidents were most common in the oldest age groups, reaching 3.7 cases/10,000 population/year in boys 16 and 17 years of age. Although all fractures were more common during the periods of the fastest skeletal growth, the difference in incidence between different causes indicated that environmental factors are more important than endogenous factors for the risk of fracture.

Influence of the blood-brain pH gradient on brain phenobarbital uptake during status epilepticus

Brain uptake and blood concentrations of phenobarbital were determined in rats during pentylenetetrazol-induced status epilepticus and compared to nonconvulsing controls. Brain phenobarbital concentrations and the brain-to-blood phenobarbital ratio were increased 2-fold in freely convulsing animals as compared to controls. The degree of systemic acidosis during motor convulsions was greater than the degree of brain acidosis. Because phenobarbital is a weak acid, this pH gradient favors movement of phenobarbital into the brain during status epilepticus. Motor paralysis prevented the development of systemic acidosis and the brain-blood partition of phenobarbital was similar to that of nonconvulsing controls. Blood phenobarbital concentrations were slightly higher in animals paralyzed during status as compared to controls, presumably due to hemodynamic effects of convulsions. These studies, as well as our previous studies with lidocaine, support the idea that the brain-blood pH gradient is an important determinant of drug uptake by the brain during seizures.