Francis W. Smith

Diagnosis of lumbosacral nerve root anomalies by magnetic resonance imaging.

This study evaluates the use of magnetic resonance imaging (MRI) in the diagnosis of lumbosacral nerve root anomalies. Prevalence of anomalous nerve roots has been based on anatomic dissection or preoperative neuroradiologic investigations. Three hundred seventy-six patients with low back pain and/or radicular pain who underwent MRI of the lumbar spine were reviewed. Sixty-five cases of nerve root anomalies were found (an incidence of 17.3%) of which 1 case of cranial origin, 5 cases of caudal origin, 2 cases of conjoined nerve root, and 57 cases of furcal nerve roots (15.1%) were identified. Furcal nerve roots were most commonly found at L3 and L4 levels and were classified, according to their division, into intra-and extraforaminal. MRI provided accurate information on lumbosacral nerve root anomalies.

Measurement of Lumbar Spine Flexion-Extension Using a Low-Field Open-Magnet Magnetic Resonance Scanner

RATIONALE AND OBJECTIVESnThe authors investigated the feasibility of using a low-field open-magnet magnetic resonance (MR) scanner to acquire functional flexion-extension images for range of motion (ROM) measurements on the lumbar spine.nnnMETHODSnSeventeen healthy subjects with no symptoms of back pain (age range, 22-59 years) were scanned in a low-field open-magnet MR scanner in the flexed, neutral, and extended positions. Each image was downloaded to a computer workstation for subsequent flexion-extension, lordosis, and ROM measurement.nnnRESULTSnData from two subjects were not analyzed because their images did not show all the lumbar vertebrae. For the remaining 15, there was a large variation in the magnitude of the ROM values (range, 9 degrees-70 degrees; mean 36.4 degrees, SD 16.5 degrees). However, there was a significant correlation between age and ROM (r = -0.63; P < 0.05).nnnCONCLUSIONSnThe low-field open-magnet MR scanner provides a method for noninvasive imaging of the lumbar spine, allowing the subject freedom of movement in the horizontal plane. This enables functional flexion-extension images of the lumbar spine to be acquired.

The increase in dural sac area is maintained at 2 years after X-stop implantation for the treatment of spinal stenosis with no significant alteration in lumbar spine range of movement

BACKGROUND CONTEXTnThe X-stop interspinous process decompression (IPD) device has been used effectively in the management of symptomatic spinal stenosis. This study examines the radiological outcomes at 2 years postoperatively after X-stop implantation.nnnPURPOSEnTo measure the effect of X-stop IPD device on the dural sac and foraminal areas at 24 months postoperatively at instrumented level in symptomatic lumbar canal stenosis. We also aimed to assess its effect on change in lumbar spine movement.nnnSTUDY DESIGNnProspective observational study.nnnPATIENT SAMPLEnForty-eight patients treated with X-stop had preoperative positional magnetic resonance imaging (MRI) scans, 40 of whom had 2 years postoperative positional MRI scans. Complete scans were available for 39 of these patients.nnnOUTCOME MEASURESnPositional MRI scans were performed pre- and postoperatively. Measurements were done on these scans and are presented as the outcome measures.nnnMETHODSnAll patients had a multipositional MRI scan preoperatively and at 6 and 24 months postoperatively. Foraminal area was measured in flexion and extension. Dural cross-sectional area was measured in standing erect and in sitting neutral, flexion, and extension (sitting) positions. The total range of movement (ROM) of the lumbar spine and individual segments was also measured.nnnRESULTSnComplete scan data for 39 patients scans were available. An increase in mean dural sac area was found in all positions. At 24 months after surgery, the mean dural sac area increased significantly in all four postures mentioned above. A small increase in mean foraminal area was noted, but this was not statistically significant. Mean anterior disc height reduced from 5.9 to 4.1 mm (p=.006) at 24 months at the instrumented level in single-level cases, from 7.7 to 6.1 mm (p=.032) in double-level cases caudally, and from 8.54 to 7.91 (p=.106) mm cranially. We hypothesize that the reduction in anterior disc heights could be a result of the natural progression of spinal stenosis with aging. There was no significant change in posterior disc heights at instrumented level or adjacent levels. The mean lumbar spine motion was 21.7 degrees preoperatively and 23 degrees at 24 months (p=.584) in single-level cases. This was 32.1 degrees to 31.1 degrees (p=.637) in double-level cases. There was no significant change in the individual segmental range of motion at instrumented and adjacent levels.nnnCONCLUSIONnX-stop interspinous device remains effective in decompressing the stenosed spinal segment by increasing the anatomic dural cross-sectional area and foraminal area of spinal canal. It does not significantly alter the ROM of lumbar spine at instrumented and adjacent levels at 24 months postoperatively.

Gym ball exercise leads to recruitment and increased water content of the paraspinal muscles: An MRI pilot study

Study design: Cross-sectional pilot study on 24 healthy volunteers. Objectives: Investigate the value of stabilization exercises using a gym ball in paraspinal muscle activation by measuring changes in muscle signal intensity on MRI before and after exercise. Background: The gym ball is commonly used for rehabilitating spinal dysfunction. It is thought to rehabilitate some key muscle groups in the trunk. Methods: Twenty-four healthy volunteers (aged 21–50, 13 female and 11 male) had special sequence MR images of the lumbar spine showing an axial section of the paraspinal muscles at L4/5 level. Afterwards all were subjected to 10 minutes of exercise on the gym ball followed by repeat MRI scans immediately, 5 and 10 minutes post exercise. Changes in the mean signal intensity at the same region of interest in multifidus, erector spinae and psoas muscles were evaluated using MRI software. Results: The mean signal intensity in the MR images of the same region in the multifidus (P < 0.03) and erector spinae (P < 0.005) muscles significantly increased after gym ball exercise. There was no statistically significant change in the signal intensity of the psoas muscle (P < 0.086). Conclusions: The multifidus and erector spinae muscles of a healthy individual can be activated by performing certain exercises

Measurement of lumbar spine intervertebral motion in the sagittal plane using videofluoroscopy

BACKGROUNDnStatic radiographic techniques are unable to capture the wealth of kinematic information available from lumbar spine sagittal plane motion.nnnOBJECTIVEnDemonstration of a viable non-invasive technique for acquiring and quantifying intervertebral motion of the lumbar spine in the sagittal plane.nnnMETHODSnVideofluoroscopic footage of sagittal plane lumbar spine flexion-extension in seven symptomatic volunteers (mean age = 48 yrs) and one asymptomatic volunteer (age = 54 yrs) was recorded. Vertebral bodies were digitised using customised software employing a novel vertebral digitisation scheme that was minimally affected by out-of-plane motion.nnnRESULTSnMeasurement errors in intervertebral rotation (± 1°) and intervertebral displacement (± 0.5 mm) compare favourably with the work of others. Some subjects presenting with an identical condition (disc prolapse) exhibited a similar column vertebral flexion-extension relative to S1 (L3: max. 5.9°, min. 5.6°), while in others (degenerative disc disease) there was paradoxically a significant variation in this measurement (L3: max. 28.1°, min. 0.7°).nnnCONCLUSIONSnBy means of a novel vertebral digitisation scheme and customised digitisation/analysis software, sagittal plane intervertebral motion data of the lumbar spine data has been successfully extracted from videofluoroscopic image sequences. Whilst the intervertebral motion signatures of subjects in this study differed significantly, the available sample size precluded the inference of any clinical trends.