Lumbar discectomy outcomes vary by herniation level in the Spine Patient Outcomes Research Trial.

BACKGROUND: The Spine Patient Outcomes Research Trial showed an overall advantage for operative compared with nonoperative treatment of lumbar disc herniations. Because a recent randomized trial showed no benefit for operative treatment of a disc at the lumbosacral junction (L5-S1), we reviewed subgroups within the Spine Patient Outcomes Research Trial to assess the effect of herniation level on outcomes of operative and nonoperative care. METHODS: The combined randomized and observation cohorts of the Spine Patient Outcomes Research Trial were analyzed by actual treatment received stratified by level of disc herniation. Overall, 646 L5-S1 herniations, 456 L4-L5 herniations, and eighty-eight upper lumbar (L2-L3 or L3-L4) herniations were evaluated. Primary outcome measures were the Short Form-36 bodily pain and physical functioning scales and the modified Oswestry Disability Index assessed at six weeks, three months, six months, one year, and two years. Treatment effects (the improvement in the operative group minus the improvement in the nonoperative group) were estimated with use of longitudinal regression models, adjusting for important covariates. RESULTS: At two years, patients with upper lumbar herniations (L2-L3 or L3-L4) showed a significantly greater treatment effect from surgery than did patients with L5-S1 herniations for all outcome measures: 24.6 and 7.1, respectively, for bodily pain (p = 0.002); 23.4 and 9.9 for Short Form-36 physical functioning (p = 0.014); and -19 and -10.3 for Oswestry Disability Index (p = 0.033). There was a trend toward greater treatment effect for surgery at L4-L5 compared with L5-S1, but this was significant only for the Short Form-36 physical functioning subscale (p = 0.006). Differences in treatment effects between the upper lumbar levels and L4-L5 were significant for Short Form-36 bodily pain only (p = 0.018). CONCLUSIONS: The advantage of operative compared with nonoperative treatment varied by herniation level, with the smallest treatment effects at L5-S1, intermediate effects at L4-L5, and the largest effects at L2-L3 and L3-L4. This difference in effect was mainly a result of less improvement in patients with upper lumbar herniations after nonoperative treatment.

An observational study of the frequency and pattern of use of epidural steroid injection in 25,479 patients with spinal and radicular pain.

BACKGROUND AND OBJECTIVES: Frequency of epidural steroid injections (ESI) and characteristics of patients receiving them are unknown or poorly described. Patients believed to respond better to ESI include young or middle-aged individuals, those with recent onset or a radicular pattern of pain, and patients without previous spinal surgery. The aim of this study is to estimate the frequency of ESI, to examine the characteristics of patients who have them recommended, and to determine if clinical practice reflects published data pertaining to indications for ESI. METHODS: Descriptive data from 25,479 selected patients with spinal and radicular pain were reviewed. Patients were grouped according to whether or not ESI was recommended, scheduled, prescribed, or continued. Prevalence of ESI use and patient characteristics were compared using standard statistical tests. RESULTS: Overall, ESI were recommended to 2,022 (7.9%) patients. Patients with lumbar pain had ESI proposed 12.6% of the time. Those with cervical and thoracic symptoms had ESI recommended 3.7% and 1.8% of the time, respectively. Patients in whom ESI was recommended were more likely to have pain radiation (P <.001), dermatomal pain distribution (P <.001), and neurologic signs (P <.001). They also had a greater incidence of comorbidities (P <.001) and were older (P <.001). There was no difference in the frequency of prior surgery (P =.169) nor was there a difference based on gender (P =.548) in patients not recommended to have ESI. Patients with symptom duration between 1 month and 1 year were more likely to have ESI recommended. CONCLUSIONS: ESI are commonly used to treat patients with spinal and radicular pain. There is some consistency between clinical practice and published recommendations for ESI use.

Designing an ambulatory clinical practice for outcomes improvement: from vision to reality--the Spine Center at Dartmouth-Hitchcock, year one.

Development of a new program for diagnosis and treatment of spine-related problems provided a unique opportunity to design and implement a new model for delivery of health care incorporating outcomes measurement and improvement. Key features include: application of microsystem thinking and interdisciplinary practice; integration of a uniform outcomes measurement tool, the Dartmouth Clinical Value Compass; and touch pad technology for data collection. This, for the first time, provided clinically meaningful point-of-service data and aggregated information for improvement. A further advantage was the ability to integrate a clinical research program within this microsystem. A multisite clinical research trial, the Spine Patient Outcomes Research Trial (SPORT), modeled on the Spine Center microsystem and funded by The National Institute of Arthritis, Musculoskeletal and Skin Diseases and the Office of Research on Woman's Health, the National Institutes of Health, and the National Institute of Occupational Safety and Health, the Centers for Disease Control and Prevention, is currently underway. The significant problems we face today cannot be solved by the same level of thinking that created them.

Population-based prediction equations for neurobehavioral tests.

Quantitative assessment of neurobehavioral function appraises brain injury from inhaled chemicals. Contemporary predicted values for tests useful in epidemiological studies have been developed with step-wise linear regression. In instances in which age and education do not match those of control groups, these equations assist in the interpretation of results of examinations of individual subjects and pilot studies. In this study, investigators considered brain function tests to be analogous in concept to pulmonary function tests. The authors used the tests to assess 293 adults in three unexposed groups from different areas of the United States. The subjects, who were contacted at random from voter registration rolls, were compensated for their time. The tests included balance, reaction time, strength, hearing, visual performance and cognitive recall, and perceptual motor and memory functions. Regression equations modeled the performance of each test and the influences of demographic factors. The investigators retained all influential factors in the equations. Age was a significant predictor for most tests. Education attainment was not a factor in any of the physiological measures, but it was a determinant in many psychological tests. Prediction equations assist investigators in the quantitative testing of chemically exposed individuals and other brain-injured individuals. The investigators verified the equations against other groups, including additional unexposed populations.

A field method for blink reflex latency R-1 (BRL R-1) and prediction equations for adults and children.

PURPOSE: To develop a field worthy apparatus for blink reflex latency R-1 (BRL R-1), to compare mechanical and electrical stimulation, to define a standardized measurement of BRL R-1, to test a field worthy procedure and to produce population-based prediction equations. METHODS: A special low voltage electromyographic (EMG) recording system was constructed which is uninfluenced by electrical and magnetic field. The supraorbital notches were stimulated mechanically using a small hammer and electrically using a stimulus of 2.0 ms duration and 2-5 mA 13. A computer program was developed which substracts the baseline for all data points and sums R-1 for 10 tests by identifying the noise floor or baseline of the EMG recording and the noise envelope. The beginning of R-1 and R-2 is defined as 2 times the noise amplitude of this envelope. BRL R-1 was compared after tap and after electrical stimulation in 16 subjects. Prediction equations were developed from data of 240 adults and 163 children unexposed to chemicals. RESULTS: Mechanically and electrically elicited mean BRL R-1 in 16 subjects was identical at 12.6 ms on the right and 12.7 ms vs 12.5 on the left. In adults, BRL R-1 depended on age. In children BRL R-1 was age, weight and height dependent. CONCLUSION: BRL R-1 elicited by supraorbital tap is field worthy, computer defined and identical to electrical BRL.

Balance measured by head (and trunk) tracking and a force platform in chemically (PCB and TCE) exposed and referent subjects.

To determine comparability of methods, postural sway was measured simultaneously with a force platform and a device that registers head (and trunk) movements (head tracking). The effects of age, sex, height, weight, shoe area, and grip strength on both measurements were examined in 162 subjects. To determine whether either method had advantages in detecting abnormal balance 46 reference subjects were compared with 116 people randomly selected from 500 residents whose well water was contaminated with polychlorinated biphenyls (PCBs) and trichloroethylene (TCE) from a metal casting plant. Speed, mean radius, and distance of sway were equally reproducible with both methods. Correlation coefficients were 0.672 with the eyes closed and 0.588 with the eyes open. The balance of those exposed to PCBs and TCE was significantly worse than that of unexposed subjects by both head tracking (1.50 + 71 cm/s v 1.27 + 0.36 cm/s; p < 0.034) and the force platform (4.93 + 1.56 N (kg force) v 4.29 + 1.14 N; p < 0.013) with the eyes closed and differences were also significant with the eyes open. Head tracking and the force platform produced equivalent results. Measurement by head tracking is recommended for field studies because the device is more portable and is less influenced by weight and height. Both methods showed impaired balance associated with years of exposure to PCBs and TCE.

A reproducible trigger for the measurement of trigeminal latencies elicited by a glabellar tap.

In order to develop a screening test of trigeminal latencies which could be used in the field, a stimulator which delivered a "tap" consisting of a focused puff of air to the glabella was compared with a tap delivered by means of a lightweight hammer with a piezoelectric trigger similar to that described by Shahani (Shahani and Young, 1972, Neurology 22, 149-154). Results were similar for both methods although the mechanical tap failed to elicit a response from the left side in one subject. The benefit of the air tap is in the reproducible force of the tap and better aim than is possible with the hammer.

Are hearing loss and balance dysfunction linked in construction iron workers?

The objective was to determine whether an association existed between hearing loss and balance dysfunction in construction workers exposed to noise. Screening pure tone audiometry and balance testing were performed using a sound emitter and dual microphone system to evaluate 78 iron workers who were compared with 128 histology technicians. Most iron workers showed hearing loss at frequencies below 3000 Hz. Their sway speeds were significantly faster both with the eyes open (1.05 (SD 0.39) v 0.91 (SD 0.22) cm/s) and with eyes closed (1.66 (SD 0.82) v 1.31 (SD 0.51) cm/s) than those of histology technicians. Coefficients for sway speed with the eyes closed and hearing loss in the left ear were significantly correlated at 500 to 8000 Hz. They were also correlated with the sway speed, eyes open, at low and high Hz. It is concluded that the use of air impact power tools in an inordinately noisy work environment makes iron workers prematurely deaf and impairs their balance. Falls may be related to balance dysfunction and impaired equilibrium. Falls from height injure and kill iron workers. Further investigations will determine whether injuries from falls are linked to these impairments.