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Biomedical subjects

A L Nachemson

Publications and source records attributed to A L Nachemson.

At least 19 recordsLinked to original sources
PubMed1992

The effect of graded activity on patients with subacute low back pain: a randomized prospective clinical study with an operant-conditioning behavioral approach.

The aim of this study was to determine whether graded activity restored occupational function in industrial blue-collar workers who were sick-listed for 8 weeks because of subacute, nonspecific, mechanical low back pain (LBP). Patients with LBP, who had been examined by an orthopedic surgeon and a social worker, were randomly assigned to either an activity group (n = 51) or a control group (n = 52). Patients with defined orthopedic, medical, or psychiatric diagnoses were excluded before randomization. The graded activity program consisted of four parts: (1) measurements of functional capacity; (2) a work-place visit; (3) back school education; and (4) an individual, submaximal, gradually increased exercise program, with an operant-conditioning behavioral approach, based on the results of the tests and the demands of the patient's work. Records of the amount of sick leave taken over a 3-year period (ie, the 1-year periods before, during, and after intervention) were obtained from each patient's Social Insurance Office. The patients in the activity group returned to work significantly earlier than did the patients in the control group. The median number of physical therapist appointments before return to work was 5, and the average number of appointments was 10.7 (SD = 12.3). The average duration of sick leave attributable to LBP during the second follow-up year was 12.1 weeks (SD = 18.4) in the activity group and 19.6 weeks (SD = 20.7) in the control group. Four patients in the control group and 1 patient in the activity group received permanent disability pensions. The graded activity program made the patients occupationally functional again, as measured by return to work and significantly reduced long-term sick leave.

Absenteeism↗
PubMed1992

A prospective evaluation of preemployment screening methods for acute industrial back pain.

Preemployment screening methods have been ineffective in predicting those at risk, and in curbing the impact of back problems in industry. Such methods have centered on individual physical factors (capacities and clinical examination). This study evaluates commonly used physical examination measures and simple historical data for its ability to predict individuals at risk for future back injury reporting in the aircraft industry. In this study, once simple historical information about previous pain treatment was known, information gained from physical factors added no significant predictive value.

Adult↗
PubMed1992

A longitudinal, prospective study of industrial back injury reporting.

The authors prospectively evaluated 3020 volunteers of the Boeing-Everett plant to assess risk factors that predispose workers to file industrial back injury claims. During four years of follow-up observation, more than 279 subjects reported acute back problems. The effect of the only predictive physical variable was explainable by a history of medical treatment. The most predictive individual factors were (1) job task dissatisfaction and (2) distress as reported on Scale 3 of the Minnesota Multiphasic Personality Inventory (MMPI). This data perhaps explains why the focus on purely physical and injury-related factors has met with little success in dealing with what has become the most expensive orthopedic problem. Clinically, nonphysical factors that significantly impact the reporting of back injuries may also affect patients' responses to medical treatment.

Accidents, Occupational↗
PubMed1992

Newest knowledge of low back pain. A critical look.

Scientific scrutiny of the low back problem demonstrates its socioeconomic importance in most industrialized societies. Natural history studies reveal that the prognosis for the low back pain patient is excellent; for those with sciatica and painful spondylolisthesis it is good. It is even relatively good for those older patients with symptoms of spinal stenosis. Although today there is a better understanding of pain, the pathomechanism of low back pain is unknown. However, for patients with sciatica, spondylolisthesis, and spinal stenosis, physicians are beginning to get a better perception of what causes the pain. Psychosocial factors, including insurance benefits, have been demonstrated to be more important than biomechanical workload not only for acute but also for chronic low back pain patients who are unable to work. Orthopedic surgeons must recognize this fact when contemplating operations for patients with ill-defined back syndromes. Rarely are diagnoses scientifically valid, nor is the effectiveness of surgery proven by acceptable clinical trials.

Back Pain↗
PubMed1991

Three-dimensional load displacement properties of posterior lumbar fixation.

Pedicular fixation devices for the posterior treatment of segmental spinal instability are thought to offer enhanced stabilization compared with sublaminar wire systems, while avoiding the immobilization of multiple normal motion segments. We compared the performance of three dissimilar stabilization systems: the Hartshill rectangle, the Acromed/Steffee interpedicular screw and plate, and the Synthes/Dick fixateur interne. Human cadaveric lumbosacral specimens were first tested intact, then after a laminectomy and a facetectomy at the L3/L4 level, and finally after the fixation devices were sequentially attached. Constructs spanning two to four vertebral levels were compared for stabilization of the resected lumbar spine segments. When tested in compression, the Acromed/Steffee system with pedicular screws at L2-L5 allowed significantly less intersegmental distraction than the Synthes/Dick construct with screws at L2 and L5 only, and less than the intact and the destabilized uninstrumented spine. When sagittally rotated, the Acromed/Steffee construct with screws at L2-L5, or at L2 and L5, allowed significantly less distraction than the intact or destabilized segments, and the construct with screws at L2 through L5 allowed less distraction than the Synthes/Dick constructs with screws at L3/L4 or L2/L5. With the exception of the Acromed/Steffee system with screws at four levels, there were no significant differences in distraction allowed between the Synthes/Dick and Acromed/Steffee constructs, or between the multisegment and single segment constructs. There were no significant differences in stiffness across levels L3/L4 with the various implants. Results indicate that the use of posterior spine constructs significantly augment the stability of posterior segmental defects. Pedicular fixation immediately cephalad and caudad to the defect provided stable fixation in this application.

Bone Plates↗
PubMed1991

A prospective study of work perceptions and psychosocial factors affecting the report of back injury.

A longitudinal, prospective study was conducted on 3,020 aircraft employees to identify risk factors for reporting acute back pain at work. The premorbid data included individual physical, psychosocial, and workplace factors. During slightly more than 4 years of follow-up, 279 subjects reported back problems. Other than a history of current or recent back problems, the factors found to be most predictive of subsequent reports in a multivariate model were work perceptions and certain psychosocial responses identified on the Minnesota Multiphasic Personality Inventory (MMPI). Subjects who stated that they "hardly ever" enjoyed their job tasks were 2.5 times more likely to report a back injury (P = 0.0001) than subjects who "almost always" enjoyed their job tasks. The quintile of subjects scoring highest on Scale-3 (Hy) of the MMPI were 2.0 times more likely to report a back injury (P = 0.0001) than subjects with the lowest scores. The multivariate model, including job task enjoyment, MMPI Scale-3, and history of back treatment, revealed that subjects in the highest risk group had 3.3 times the number of reports in the lowest risk group. These findings emphasize the importance of adopting a broader approach to the multifaceted problem of back complaints in industry and help explain why past prevention efforts focusing on purely physical factors have been unsuccessful.

Adult↗
PubMed1991

Midterm follow-up of young patients fused in situ for spondylolisthesis.

To evaluate the results of posterolateral fusion alone (66 patients) and combined posterolateral and anterior fusion (39 patients) in situ, 105 consecutive patients younger than 25 years of age with spondylolisthesis, retrospectively were examined clinically and radiologically. The follow-up rate was 98% after a mean of 8.2 years (range, 2.0-15.3). Pre- and postoperative progression of slip was rare (6% and 1%, respectively), and no prognostic factors were found. The definite pseudarthrosis rate was 6%. In patients with low- and high-grade slip, 67% and 88% (respectively) were satisfied at follow-up, suggesting that the indication for operative treatment in patients with low-grade slip is relative.

Adult↗
PubMed1991

Instability of the lumbar spine. Pathology, treatment, and clinical evaluation.

At present, no scientific evidence exists on how to make the diagnosis of lumbar instability; nor is there any proof of successful treatment--conservative or surgical. Judging from available clinical studies, surgical fusion operations may be useful in properly selected patients with spondylolisthesis or in situations for which the surgical approach has necessitated destabilization by laminectomy and facetectomy. Refined biplanar radiographic techniques promise better definitions for future diagnostic studies.

Follow-Up Studies↗
PubMed1990

The role of spinal flexibility in back pain complaints within industry. A prospective study.

Commonly used clinical measurements of spinal flexibility in the sagittal and frontal planes were examined as predictors of future back pain reports within industry. The study sample consisted of 3,020 aircraft manufacturing employees who were examined and tracked for more than 4 years for reports of back pain. Modified Schober, sit-and-reach, and lateral bending measurements were not significantly associated with risk of future back pain reporting, nor were any trends present. There was a statistically significant relationship between decreased flexibility and reports of current or previous back problems. However, the differences in flexibility between subjects with and without a history of back problems were too small to be of practical significance.

Adult↗
PubMed1990

Anthropometric and clinical measures as predictors of back pain complaints in industry: a prospective study.

A prospective, longitudinal investigation was conducted to investigate anthropometric and clinical examination measures as predictors of future back pain reports in industry. Associations between these measures and a history of back problems were examined as well. Participants in the study included 3,020 aircraft manufacturing employees who underwent an examination and then were tracked for greater than 4 years for subsequent back pain reports. Back symptoms elicited on straight leg raising (SLR) was the measure most significantly associated with subsequent back pain reporting among both men and women (p less than 0.0001). The only variables to add predictive value in addition to back pain on SLR were age and weight in women, and history of back problems and age in men.

Adult↗
PubMed1989

A prospective study of the role of cardiovascular risk factors and fitness in industrial back pain complaints.

The authors conducted a prospective study of risk factors for industrial back pain complaints among 3,020 aircraft manufacturing employees. The study subjects completed a cardiovascular risk questionnaire, and were asked about their smoking status and past medical history, including previous back problems. Premorbid submaximal treadmill testing to predict maximum oxygen uptake (Vo2max) was completed in 2,434 subjects who were not excluded from testing due to cardiovascular risk screening. During several years of subsequent follow-up, 279 subjects reported back problems. Those who reported smoking at the time of the premorbid examination were significantly more likely to report a subsequent back problem than nonsmokers (P = 0.002). When controlling for sex and age, cardiovascular fitness, as measured through VO2max, was not predictive of future back injury reports (P = 0.26).

Adult↗
PubMed1988

Chemonucleolysis for sciatica. A critical review.

Intradiscal injection of chymopapain for the treatment of sciatica due to disc herniation has been used for more than 25 years, but is still under debate. We review the indications, complications, and clinical results, and discuss the tissue effects of chymopapain. The results following surgical disc removal versus chymopapain injection indicate that surgery with removal of the disc hernia through a small laminotomy remains the documented treatment of choice for patients with proven disc herniation and sciatica in whom conservative treatment has failed.

Chymopapain↗
PubMed1987

Steindler award lecture. Cross the borders.

The orthopaedic scientists of today, whether a clinician or a basic scientist, must cross both interdisciplinary and national borders to advance the field. Examples derived from the author's own experience of such border crossings are given, mainly as they relate to research in spinal disorders.

Back Pain↗
PubMed1987

Results of surgical treatment of adults with idiopathic scoliosis.

The outcome of surgical treatment of idiopathic scoliosis in forty-five adults was studied with special attention to pain, function, self-image, and pulmonary function. All of the patients were more than twenty-five years old at operation and had been followed for more than three years. Every patient who was operated on by one of us (J. E. H.) and who met these criteria was evaluated. The magnitude of the curves averaged 66 degrees. Standardized gradations of pain and function showed improvement over-all, but significant impairment remained. There was a reduction in the levels of peak and constant pain, but no change in the frequency of peak pain after operation. The number of patients who were pain-free after surgery was not increased. Functional impairment due to the scoliosis was lessened, and the ability to perform the common activities of daily living was improved, but no important changes in occupation or recreational activity were recorded. Correlations of pain or function, or both, and the changes in either, were found with only two parameters: age at follow-up and physical occupation. Pulmonary function, as measured, did not change. Eighteen (40 per cent) of the patients had a minor complication and ten (20 per cent), a major complication; there was one death, due to pulmonary embolism, of a patient who was excluded from the series. In view of the high rate of complications, the limited gains to be derived from spinal fusion should be assessed and clearly explained to patients before the procedure is undertaken.

Activities of Daily Living↗
PubMed1986

Valsalva maneuver biomechanics. Effects on lumbar trunk loads of elevated intraabdominal pressures.

The ability of a partial or full Valsalva maneuver (voluntary pressurization of the intraabdominal cavity) to unload the spine was investigated in four subjects. During the performance of five isometric tasks, intraabdominal and intradiscal pressures and surface myoelectric activities in three lumbar trunk muscle groups were measured. The tasks were carried out without voluntary pressurization of the intraabdominal cavity and then when the subjects performed partial and full Valsalva maneuvers. A biomechanical model analysis of each task was made to help interpret the experimental measurements. Intraabdominal pressure was found not to be an indicator of spine load in these experiments. The Valsalva maneuvers did raise intraabdominal pressure, but in four of the five tasks increased rather than decreased lumbar spine compressions occurred.

Abdomen↗