The value of magnetic resonance imaging of the lumbar spine to predict low-back pain in asymptomatic subjects : a seven-year follow-up study.

BACKGROUND: In 1989, a group of sixty-seven asymptomatic individuals with no history of back pain underwent magnetic resonance imaging of the lumbar spine. Twenty-one subjects (31%) had an identifiable abnormality of a disc or of the spinal canal. In the current study, we investigated whether the findings on the scans of the lumbar spine that had been made in 1989 predicted the development of low-back pain in these asymptomatic subjects. METHODS: A questionnaire concerning the development and duration of low-back pain over a seven-year period was sent to the sixty-seven asymptomatic individuals from the 1989 study. A total of fifty subjects completed and returned the questionnaire. A repeat magnetic resonance scan was made for thirty-one of these subjects. Two neuroradiologists and one orthopaedic spine surgeon interpreted the original and repeat scans in a blinded fashion, independent of clinical information. At each disc level, any radiographic abnormality, including bulging or degeneration of the disc, was identified. Radiographic progression was defined as increasing severity of an abnormality at a specific disc level or the involvement of additional levels. RESULTS: Of the fifty subjects who returned the questionnaire, twenty-nine (58%) had no back pain. Low-back pain developed in twenty-one subjects during the seven-year study period. The 1989 scans of these subjects demonstrated normal findings in twelve, a herniated disc in five, stenosis in three, and moderate disc degeneration in one. Eight individuals had radiating leg pain; four of them had had normal findings on the original scans, two had had spinal stenosis, one had had a disc protrusion, and one had had a disc extrusion. In general, repeat magnetic resonance imaging scans revealed a greater frequency of disc herniation, bulging, degeneration, and spinal stenosis than did the original scans. CONCLUSIONS: The findings on magnetic resonance scans were not predictive of the development or duration of low-back pain. Individuals with the longest duration of low-back pain did not have the greatest degree of anatomical abnormality on the original, 1989 scans. Clinical correlation is essential to determine the importance of abnormalities on magnetic resonance images.

Normal lumbar vertebrae: anatomic, age, and sex variance in subjects at proton MR spectroscopy--initial experience.

Fifty-seven subjects underwent proton magnetic resonance (MR) spectroscopy of the second lumbar vertebra to evaluate single-voxel and multivoxel techniques. Measurements included lipid-to-water ratios, lipid fractions, and line width. These data provide information about vertebral fat content. There was an age-dependent linear increase in fat content and sex dependence. A higher fat concentration was found in men. The observed spectra provide a basis for future study to determine clinical utility of vertebral proton MR spectroscopy.

2D CSI proton MR spectroscopy of human spinal vertebra: feasibility studies.

This report focuses on proton magnetic resonance spectroscopy (1H MRS) of spine vertebra acquired with two-dimensional chemical shift imaging (2D CSI), utilizing the stimulated echo acquisition mode (STEAM) sequence. Both validity and reproducibility studies were performed. To validate the 2D CSI method, its spectra were compared with those obtained with the single-voxel (SV) method. Five normal volunteers were scanned. The reproducibility of 2D CSI was examined by performing spectroscopy on two different occasions, on three normal volunteers. Data show that the STEAM 2D CSI technique results in MRI spectra comparable to those obtained with the STEAM SV method. 2D CSI offers significant time savings and convenient multi-voxel spectral analysis at a substantially higher signal-to-noise ratio. The 2D CSI method was then applied to a patient with a small vertebral hemangioma. The results demonstrated that the voxels containing the hemangioma exhibit different spectra than the neighboring voxels of the same vertebra. Additionally, a case of vertebral osteoporosis was investigated. Results showed a significant increase in the lipid-to-water ratio (LWR). It is suggested that 2D CSI may be powerful in identifying physiological as well as pathological changes of the bone marrow. Furthermore, covering a more extensive area of the vertebral body will maximize the chances of depicting a small focus of pathologic tissue. A more detailed bone marrow pattern was noticed in on one subject whose spectra show more lipid peaks.

A randomized prospective study of posterolateral lumbar fusion. Outcomes with and without pedicle screw instrumentation.

STUDY DESIGN: A prospective evaluation of the clinical and radiographic outcomes of 71 patients who underwent lumbar fusion, with or without transpedicular instrumentation. The patients completed a questionnaire that determined pain relief, medication use, return to work, and overall satisfaction with surgery. OBJECTIVES: To explore the effect, if any, of instrumentation on the outcome of lumbar fusion surgery, according to reports of the patients, and whether there is a correlation between the radiographic determination of a solid fusion and the same patient-reported outcome. SUMMARY OF BACKGROUND DATA: The literature on this topic reports pseudarthrosis rates from 0% to 57% and good to excellent results from 56% to 95%. These studies provide no clear-cut recommendations concerning the effect of added lumbar instrumentation on patient-reported outcome in a prospective manner using concurrent control subjects. METHODS: The patients were randomized to groups with and without instrumentation after deciding to undergo a lumbar fusion and consenting to enter the study. Radiographs were obtained and questionnaires filled out at 6 weeks, 6 months, 1 year, and 2 years after surgery. RESULTS: There was no statistical difference in patient-reported outcome between the two groups. There was a slight nonsignificant trend toward increased radiographic fusion rate in the group with instrumentation that did not correlate with an increased patient-reported improvement rate. CONCLUSIONS: These results do not provide data that indicate a benefit in outcome from added instrumentation in elective lumbar fusions.

Helmet and shoulder pad removal from a player with suspected cervical spine injury. A cadaveric model.

STUDY DESIGN: Video fluoroscopy was used to evaluate the motion in an unstable spine during helmet and shoulder pad removal. OBJECTIVE: To observe the amount of motion that occurs during the removal of helmet and shoulder pads in an injured spine. SUMMARY OF BACKGROUND DATA: Removal of shoulder pads and helmet from a football player with suspected cervical spine injury can be particularly hazardous. How much flexion occurs at the unstable level during removal of equipment is unknown. METHODS: Six fresh cadavers were used in the study. In three, an unstable C1-C2 segment was created by transoral osteotomy of the base of C2. In the remaining three, instability was created at C5-C6 by a posterior release. Under fluoroscopic recording, the helmets were removed by first removing the chin strap, face mask, and ear pieces. With the neck stabilized, the helmet was carefully removed. The shoulder pads were carefully removed, with the head stabilized. Angulation, distraction, and space available for the cord were measured at C1-C2. Translation, angulation, distraction, and change in disc height were measured in the specimens with unstable C5-C6. RESULTS: In cadavers with C1-C2 instability, the mean change in angulation was 5.47 degrees, and space available for the cord was 3.91 mm. Shoulder pads were removed while the head was stabilized. The mean change in angulation at C1-C2 was less during removal of shoulder pads than during helmet removal at 2.9 degrees. Space available for the cord was 2.64 mm. Distraction was also greater during helmet removal (2.98 mm) than during shoulder pad removal (1.76 mm). In the unstable spine, the change in displacement in translation was greater during shoulder pad removal (3.87 mm), than during helmet removal (0.41 mm). Disc height change was similar. Distraction of the spinous processes was greater during helmet removal (3.68 mm) than during shoulder pad removal (1.37 mm). Angulation was similar in both maneuvers. CONCLUSIONS: Helmet and shoulder pad removal in the unstable cervical spine is a complex maneuver. In the unstable C1-C2 segment, helmet removal causes more angulation in flexion, more distraction, and more narrowing of the space available for the cord. In the lower cervical spine (C5-C6), helmet removal causes flexion of 9.32 degrees, and during shoulder pad removal the neck extends 8.95 degrees, a total of approximately 18 degrees. Disc height changes from 1.24 mm of distraction to 1.06 mm of compression during helmet removal and shoulder pad removal for a total 2.3-mm change. Translation, which correlates with the change in the space available for the cord, is greater at C5-C6 during shoulder pad removal. Because most of the cadavers had C5 anteriorly displaced on C6 to begin with, the extension force during shoulder pad removal caused a 3.87-mm change in reduction of C5 on C6. Because of the motion observed in the unstable spine, helmet and shoulder pad removal should be performed in a carefully monitored setting. They should be removed together by at least three, preferably four, trained people.

Cervical spine alignment in the immobilized football player. Radiographic analysis before and after helmet removal.

We investigated the effect of football helmet removal on the sagittal alignment of the cervical spine. A quantitative radiographic assessment of relative cervical spine position in subjects immobilized to a standard backboard wearing shoulder pads either with or without a helmet was performed. Comparison was made to a control situation with subjects on a backboard wearing no equipment. Ten subjects were studied using lateral computed tomographic scout films; each subject served as his own control. Radiographs were measured for overall sagittal cervical alignment and the amount of lordosis or kyphosis present within specific segments of the cervical spine. Mean values for each of the three defined situations (no equipment, shoulder pads and helmet, shoulder pads alone after helmet removal) were calculated and subjected to statistical analysis. No statistically significant difference in cervical sagittal alignment was noted when either no equipment or both shoulder pads and helmet were worn. In contrast, a statistically significant increase in cervical lordosis (extension) was found when comparing the control situation to that when only shoulder pads were worn after the helmet had been removed. The majority of this increase occurred in the subaxial spine. Therefore, the authors recommend that football players with a potential cervical spine injury be immobilized for transport with both their helmet and shoulder pads left in place, thereby maintaining the neck in a position most closely approximating "normal."

The use of magnetic resonance imaging in the diagnosis of lumbar disc disease.

Low back pain is a common malady, affecting up to 80% of adults at some time. Our diagnostic capabilities have been markedly improved with the introduction and evolution of magnetic resonance imaging. MRI is an accurate modality in the diagnosis of disc herniation, as well as recurrent disc herniation, degenerative disc disease, and other abnormalities that may present as back pain.

Complications and long-term outcome of upper cervical spine arthrodesis in patients with Down syndrome.

STUDY DESIGN: A retrospective review of 15 patients with Down syndrome who had undergone arthrodesis of the upper cervical spine for instability. OBJECTIVES: To determine the complication rate and long-term outcome after posterior cervical arthrodesis for upper cervical instability in patients with Down syndrome. SUMMARY OF BACKGROUND DATA: Atlantoaxial instability is common in patients with Down syndrome, and fusion of the upper cervical spine has been recommended for patients who have instability, with or without myelopathy. Unfortunately, the results of posterior cervical arthrodesis are not well reported, and the natural history of this condition is unknown. METHODS: Fifteen patients with an average follow-up period of 74.6 months (range, 24-142 months) were reviewed after posterior arthrodesis of the upper cervical spine. Twelve patients were reexamined by the investigators specifically for the purpose of this study, and three patients had long-term follow-up results available from chart review. RESULTS: Eleven of 15 patients (73%) sustained 23 major complications including nonunion, loss of reduction, neurologic deterioration, late subaxial instability, infection, and wound dehiscence. Six patients (40%) required seven reoperations to address a complication. Ultimately, 12 patients (80%) obtained osseous union, but a definite clinical improvement was identifiable in only three patients, whereas two others had worsened neurologically at latest follow-up evaluation. CONCLUSIONS: A high complication rate should be anticipated after posterior arthrodesis of the upper cervical spine in patients with Down syndrome. A cautious approach to asymptomatic instability in this condition is advocated.

Maurice Klippel.

Maurice Klippel (1858-1942) was a turn-of-the-century French internist with a special interest in neurology and psychiatry. He authored numerous medical papers in these disciplines, but is best known to spine surgeons for his description, co-authored with Andre Feil, of a patient with congenital fusion of the cervical vertebrae, a condition now known as Klippel-Feil syndrome.

The morbidity of heparin therapy after development of pulmonary embolus in patients undergoing thoracolumbar or lumbar spinal fusion.

STUDY DESIGN: The postoperative course of patients who developed a pulmonary embolus after thoracolumbar or lumbar spinal fusion treated with heparin was studied to quantify the morbidity risk of anticoagulation. OBJECTIVE: To compare the morbidity risk of heparinization with that of an alternative form of therapy--inferior vena cava filter placement. SUMMARY OF BACKGROUND DATA: Therapeutic heparinization was the current treatment of choice for patients who develop thromboembolic disease after surgery. Although heparin usage was reported to be associated with a number of complications after other orthopedic and general surgical procedures, no information was available to identify complications of heparinization after lumbar or thoracolumbar spine surgery or to define the risk of such complications. METHODS: Twenty-two members of the Scoliosis Research Society were polled to determine their experiences with the anticoagulation of this subset of patients. Surgeons polled had a combined experience of 250 man-years and had performed more than 13000 thoracolumbar and lumbar spinal fusions. The MEDLINE database was used to review pertinent English language publications describing inferior vena cava filter complications, effectiveness, safety, and indications for use. RESULTS: Nine patients were located who fit the inclusion criteria of this study. Six (67%) had complications attributable to heparinization. Clinically significant complications of filter placement ranged from 0.12% to 10.1%. CONCLUSIONS: Heparinization after the development of pulmonary embolus in patients recently undergoing spinal fusion is associated with a high complication rate. The morbidity of vena cava filter placement is low and should be considered a treatment alternative in the treatment of patients who experience pulmonary embolus after surgery.

The influence of anulotomy selection on disc competence. A radiographic, biomechanical, and histologic analysis.

STUDY DESIGN: This study analyzed the radiographic, biomechanical, and histologic attributes of three commonly used anulotomy techniques. OBJECTIVES: This study defined the propensity of the anulus fibrosus to heal after discectomy and correlated biomechanical differences between subgroups of the motion segments studied. SUMMARY OF BACKGROUND DATA: No previous report that compares the influence of anulotomy selection on disc competence exists. METHODS: Anulotomies were performed on the anterolateral aspects of the lumbar discs of 54 adult goats. The goats were randomly assigned to one of three subgroups containing 18 animals. In subgroup A, a full-thickness anular window was excised. In subgroup B, a full-thickness cruciate anulotomy was accomplished. In subgroup C, a full-thickness anulotomy was developed by inserting a trocar, 2.5 mm in diameter, into the disc. RESULTS: Histologic analysis revealed that primary anular healing did not occur in any specimen. The anulotomy tracts in subgroup C (trocar) were consistently narrower than those of subgroups A and B. Discography demonstrated the presence of severe and early disc degeneration with subgroup A (anular window), a finding not observed within the trocar anulotomy group. Biomechanical testing demonstrated increased resistance to pull out by the trocar anulotomy group at 4 weeks, as well as increased torsional stiffness of the motion segment when compared to both window and cruciate anulotomy. CONCLUSIONS: The authors conclude that attempts should be made to minimize injury to the anulus fibrosus during the performance of discectomy.

Muscle flap closure for salvage of complex back wounds.

STUDY DESIGN: The use of muscle flaps for closing complex thoracolumbar and lumbar spine wounds was studied retrospectively. Five patients in whom traditional, conservative treatment modalities did not work underwent a variety of muscle flap closures with successful healing. OBJECTIVES: Patients with complicated back wounds ranging from exposed hardware to post-traumatic defects were treated initially with conservative treatments. The authors evaluated the efficacy of applying techniques and knowledge gained from complex lower extremity wound coverage of back wounds. SUMMARY OF BACKGROUND DATA: Six muscle transfer procedures were performed on five patients. All patients were closed with local muscle flaps using the trapezius and latissimus dorsi muscles. METHODS: Success was defined as a closed stable wound that needed no future surgery nor allowed the primary defect to heal before hardware removal. There was no evidence of chronic infection. Surgical hardware was salvaged in one of three patients. RESULTS: All were successfully closed and have been followed up to 30 months without evidence of recurrence. CONCLUSIONS: The cases presented illustrate the usefulness of rotation flaps when there is an extensive soft tissue defect that has exposed neural, osseous, and foreign structures. The use of local transposition muscle flaps as an adjunct in closing complex back wounds has been very successful in our experience. Although recurrent infection may occur, this technique has facilitated the establishment of a soft tissue envelope to achieve short- and long-term wound healing.

Management of retroperitoneal chylous leakage.

Lymphatic complications are uncommon after spinal surgery. Postsurgical collections of lymph may result in chyloma, chylothorax, chylous ascites, or chyloretroperitoneum. Recommended treatment of chylothorax or chylous ascites includes drainage, and a low-fat diet using medium-chain triglyceride or total parenteral nutrition. The only reported case of chyloretroperitoneum concluded with a recommendation for retroperitoneal drainage. The authors present a series of three patients who underwent anterior spinal procedures complicated by retroperitoneal lymphatic injury. All three were treated without retroperitoneal drains, and at follow-up, none has shown any adverse sequelae from this method of treatment. The authors disagree with past recommendations for drainage of the retroperitoneal space because this may prolong drainage and deplete nutrition.

A radiographic comparison of short-arm cast and plaster and fiberglass wrist splints.

Prepackaged plaster and fiberglass splints are used in many emergency departments. This study evaluated the effectiveness of short-arm cast (SAC), volar fiberglass wrist splint (FWS), and volar plaster wrist splint (PWS) in limiting wrist range of motion. Ten healthy male volunteers between the ages of 18 and 35 years were included. Each wrist on each volunteer was immobilized with SAC, FWS, and PWS. Wrist radiographs were taken with each appliance and angular motion measured by two radiologists. PWS performed better than FWS in flexion, extension, radial deviation, and ulnar deviation (all P < .05). PWS was not statistically different than SAC in limiting flexion, extension, or radial deviation, although SAC performed better in ulnar deviation (P < .05). PWS limits wrist motion more effectively than FWS and performs in a similar manner to SAC in flexion, extension, and radial deviation.

Vertebrodiatasis experimental lengthening of the juvenile goat spine.

The purpose of this study is to describe the biology of spinal lengthening (vertebrodiatasis) in a juvenile goat model. A small Orthofix dynamic fixator was affixed to 5.5 mm pedicular halfpins placed bilaterally at T12, L1, L5 and L6 in six juvenile goats. Distraction was performed across vertebral endplates between L1 and L5. Uninstrumented twins served as controls. Two pairs of animals were deleted due to anesthetic complications. Lumbar lengthening was successful in 3 animals resulting in an increase in length of up to 696% from L1 to L5 compared to the growth rate of the controls (mean 4.3 cm vs. mean .56 cm, respectively). Lengthening of the spinal cord was not associated with brain stem migration or spinal cord injury.

Pathomechanical analysis of thoracolumbar burst fracture reduction. A calf spine model.

Burst fractures were created in the spines of twelve dairy calves and the mechanism of indirect canal clearance studied. The spines were reduced posturally and divided in to four subsets--control, and subsets in which either the posterior longitudinal ligament (PLL), the PLL and annulus, or posterior osteoligmentous structures were sectioned. The specimens were then instrumented and further reduction obtained through application of extension and distraction forces. Statistically significant reduction of the intracanal burst fragment occurred even if the PLL or PLL and annulus were incompetent but did not occur in that group in which the posterolateral complex had been sectioned.

Spine injuries in combat troops--Panama, 1989.

Operation Just Cause was until recently the largest American combat operation since Vietnam, and remains the largest nighttime parachute operation since World War II. All 252 casualties were airlifted to San Antonio, Texas, for medical treatment. Greater than 80% sustained orthopedic injuries. Sixteen patients were admitted for injuries to the back or neck. Three of the four patients with significant fractures or fracture-dislocations were paraplegic. Two of the three patients with gunshot wounds to the back required extensive reconstruction for wound management. In addition to the 252 casualties, there were 23 fatalities, among whom 7 suffered major injuries to the spine. Spine injuries represented the most significant source of long-term morbidity among those soldiers wounded in combat in Panama, and were common among the fatalities. Noteworthy in these cases was the high percentage of severe neurologic injuries in patients with significant fractures (75%), particularly fractures associated with gunshot wounds. Also of interest were the cases of major soft tissue injury associated with high-velocity gunshot wounds (66%) and the extensive soft tissue surgery needed to treat these injuries.

Posterior sacroiliac fixation using a sacral pedicle targeting device: an anatomical study.

This study compares the accuracy of posterior sacroiliac (SI) screw placement using a "free-hand" method, without the use of fluoroscopy, versus a specially developed targeting device. Posterior SI screws were inserted after exposing the iliac wing in five cadavers on one side, and inserted percutaneously with a unique targeting device on the opposite side. Fluoroscopy was not used for screw or pedicle placement on either side. Computed tomography and dissection results were then used to grade screw placement for both sides. A statistically significant difference between the sides was found. More importantly, three screws on the free-hand side violated major neurovascular structures. The regional anatomy was defined: structures most at risk are the iliac vein ventrally and the sacral canal dorsally. A highly variable "safe zone" (mean arc 43 degrees at the S1 level and 30 degrees at the S2 level) was established. Inclination of the SI joint was also defined (mean 29 degrees at the S1 level and 17 degrees at the S2 level). SI screw placement using the specially developed targeting device is technically less demanding, requires less soft tissue dissection, allows variable placement, and poses minimal risk to major neurovascular structures. Our limited clinical experience with the device is encouraging. The potential application of this technique to unstable vertical shear fractures is appealing.

Results of lumbar pseudarthrosis repair.

Forty patients underwent 47 procedures for repair of a lumbar pseudarthrosis at the University of Minnesota, Twin Cities Scoliosis Center between 1973 and 1986. Forty-three procedures in 36 patients with a minimum follow-up of 2 years were reviewed. Symptoms at the time of surgery included back pain (100%), leg pain (61%), subjective neurologic symptoms (49%), and thigh pain (35%). The diagnosis was made most commonly on the basis of pain radiographs (70%). In 38 cases, posterolateral fusion was performed, using segmental sublaminar wiring in 37%, a variable screw plate in 29%, Harrington compression rods in 16%, and no implant in 18%. Anterior interbody fusion was performed in six cases, including one combined fusion. Follow-up averaged 4.4 years. Solid fusion was achieved in 49% of cases. Eighty-six percent of patients continued to have low-back pain. Clinical outcomes were graded as excellent in 7%, good in 35%, fair in 9%, and failure in 49%. Significantly improved results were seen in patients in whom a solid fusion was obtained (p less than 0.005), in patients who had undergone only one prior surgery on the lumbar spine (p less than 0.01), and in patients in whom the initial fusion had been performed for spondylolisthesis rather than a primarily degenerative disorder (p less than 0.025). A trend toward better results was seen in cases in which the patient did not complain of leg pain preoperatively, in which a Workers' Compensation claim was not involved, and in which a prior attempt at pseudarthrosis repair had not been performed.(ABSTRACT TRUNCATED AT 250 WORDS)