The transfer of disc pressure to adjacent discs in discography: a specificity problem?

STUDY DESIGN: In vivo experimental study. OBJECTIVE: The primary objective of the study was to investigate pressure transmission to adjacent discs during discography. A secondary objective was to quantify the transmitted pressure, both in contrast injected and noninjected porcine intervertebral discs. SUMMARY OF BACKGROUND DATA: Discography is used to before surgery identify painful discs. A pain response during discography that is concordant with the patient's experienced back pain is regarded as an indication that the injected disc is the source of pain. However, the sensitivity and specificity of discography are matters of debate. Pressure-controlled discographies have been reported to reduce the number of false-positive discs using low pressure criteria. Preliminary data indicated a transfer of pressure from an injected to an adjacent disc during discography. Pressure transmission in vivo during lumbar discography, not reported before might, if clinically present, contribute to a false-positive diagnosis. METHODS: Thirty-six lumbar discs in 9 adolescent pigs were investigated. Intradiscal pressure was recorded during contrast injection, using a 0.36/0.25 mm fiber-optic pressure transducer inserted into the nucleus pulposus via a 22 G needle. The pressure was measured simultaneously in 2 adjacent discs during contrast injection into 1 of the discs at pressures up to 8 bar. Transmitted pressure was recorded both in noninjected discs and in discs that were prefilled with contrast. RESULTS: Thirty-three discs were successfully examined. During contrast injection, there was an intradiscal pressure rise in the adjacent disc with a median value of 16.0% (range, 3.2-37.0) over baseline pressure. There was no significant difference in pressure increase between the noninjected and prefilled discs (P < 0.68). CONCLUSION: Discography of porcine discs induces a pressure increase in adjacent discs. A similar pressure transfer during human clinical discography might elicit false-positive pain reactions.

Utility of spine surgery: a comparison of common elective orthopaedic surgical procedures.

STUDY DESIGN: A 1-year prospective observational cohort study. OBJECTIVE: To compare the utility before and 1 year after elective spine surgery with some other common orthopaedic surgical procedures. SUMMARY OF BACKGROUND DATA: By using global measures like EQ-5D and SF-36 for the determination of the utility, the changes in quality of life, quality of life (QoL) after an intervention different diagnoses, and treatments can be compared. Total hip replacement (THR) has become almost golden standard in this respect. METHODS: Seven hundred seventy-seven subjects with different common orthopaedic diagnoses scheduled for elective surgery were just before surgery and 1 year after surgery answering both EQ-5D and SF-36. Four groups with different spine diagnoses and procedures were formed and compared with 8 other diagnoses and treatment groups. RESULTS: Before surgery, subjects with spine diagnoses reported the lowest QoL of all diagnoses compared. Surgery for spinal stenosis, spondylolisthesis, and instability meant the largest improvement of all surgical interventions. Surgery for NHP gave a moderately good improvement, whereas surgery for CLBP only marginally improved those operated. Particularly THR but also TKR more or less completely normalized QoL but made it from a relatively high preoperative level. The greatest improvements after spine surgery, other surgical procedures, and different diagnoses were in the pain/discomfort domain. CONCLUSION: Spinal surgery in spinal stenosis, spondylolisthesis, and instability had in comparison to other types of elective orthopaedic surgery an outstanding better ability to improve the operated subject's health-related quality of life than other types of elective orthopaedic surgery. The utility of HNP surgery was somewhat lower and was rather marginal for those operated for nonspecific CLBP.

The relationship between the cross-sectional area of the cauda equina and the preoperative symptoms in central lumbar spinal stenosis.

STUDY DESIGN: A cross-sectional registry and imaging cohort study. OBJECTIVES: To study the association between typical symptoms and signs of central spinal stenosis and the minimum cross-sectional area (mCSA) of the cauda equina in patients subsequently undergoing surgery. SUMMARY OF BACKGROUND DATA: Relations between mCSA and the symptoms of spinal stenosis have not been studied before. SUBJECTS AND METHODS: The preoperative walking ability, pain in the leg(s) and back, duration of symptoms and quality of life in 82 men and women subsequently operated for spinal stenosis were related to the digitally determined CSA of the single most constricted level, mCSA of their lumbar spines. RESULTS: A smaller mCSA was directly related to a shorter walking distance before claudication. A small mCSA meant more leg and back pain and a lower health-related quality of life. For those with a walking ability <100 m, the average mCSA was around 53 mm; whereas it was just <69 mm for those able to walk >500 m. The average mCSA did not differ depending on gender, age, or vertebral level. CONCLUSIONS: The mCSA was a strong predictor of the preoperative walking ability, leg and back pain, and was directly related to the quality of life of patients with central spinal stenosis.

The cost-utility of lumbar disc herniation surgery.

The cost and utility of surgery for a herniated lumbar disc has not been determined simultaneously in a single cohort. The aim of this study is to perform a cost-utility analysis of surgical and nonsurgical treatment of patients with lumbar disc herniation. Ninety-two individuals in a cohort of 1,146 Swedish subjects underwent lumbar disc herniation surgery during a 2-year study. Each person operated on was individually matched with one treated conservatively. The effects and costs of the treatments were determined individually. By estimating quality of life before and after the treatment, the number of quality adjusted life years (QALY) gained with and without surgery was calculated. The medical costs were much higher for surgical treatment; however, the total costs, including disability costs, were lower among those treated surgically. Surgery meant fewer recurrences and less permanent disability benefits. The gain in QALY was ten times higher among those operated. Lower total costs and better utility resulted in a better cost utility for surgical treatment. Surgery for lumbar disc herniation was cost-effective. The total costs for surgery were lower due to lower recurrence rates and fewer disability benefits, and surgery improved quality of life much more than nonsurgical treatments.

The costs for persons sick-listed more than one month because of low back or neck problems. A two-year prospective study of Swedish patients.

The total costs for patients who are sick-listed due to back and neck problems have not previously been determined prospectively on an individual basis. This study aimed to determine the total cost to a society, based on individually assessed costs of health services and loss of production in people who are sick-listed 28 days or more for back or neck problems. Detailed data on individuals' health-care consumption due to back or neck problems was collected through prospectively entered diaries and questionnaires, after 4 weeks, 3 months, 1 and 2 years, in a consecutively selected cohort of 1,822 employed persons aged between 18 and 59 years. Costs for health care and production losses due to work absenteeism were determined individually and combined to render total costs to society. The costs for all medical services during the 2-year study were 6.9% of total costs for back and neck problems. The single most expensive medical service was surgery. Transferred to a national level, annual total costs for back and neck problems corresponded to 1% of GNP. In conclusion, direct health-service costs were a small fraction of the total costs, consequently indirect costs offer the greatest potential for savings.

Swedish Council on Technology Assessment in Health Care (SBU). Chapter 6. Sickness absence due to back and neck disorders.

The scientific evidence on the causes for sick leave attributed to back and neck disorders was reviewed. Categories were established for acute, recurring, and chronic problems based on the duration of the sick leave period. Forty-eight articles were found to be relevant, whereof two were of high quality and 26 were of medium or low quality. Quality was assessed exclusively in relation to the aim of this systematic review. The results reveal limited published research on causes for sick leave from back and neck disorders. The generalisability of the findings is also limited since most of the subjects were men and employees in manufacturing industries. Women, white-collar workers, employees in the public sector (care, social services, schools, etc) were underrepresented in the studies. Hence, these groups and areas should be studied further to verify conclusions and enhance knowledge about the causes for sick leave from back and neck disorders. The following factors were found to have consistent, but limited, support as regards their influence on the risk for sick leave due to back and neck disorders: (a) heavy physical workload, bent or twisted working position, and low work satisfaction increases the risk for short-term and long-term sick leave; (b) specific back diagnoses and previous sick leave due to back disorders increases the risk for short-term and long-term sick leave; (c) female gender, smoking, exposure to vibration, and deficient social support were not found to significantly increase the risk for short-term and long-term sick leave; (d) self-reported pain and functional impairments were associated with a high risk for long-term sick leave; (e) longer employment periods reduced the risk for short-term sick leave; (f) perceived demands at work did not influence short-term sick leave; (g) female gender and higher age increases the risk for disability pension.

[Four years on a waiting lists for surgery--an expensive option. Millions in lost production while waiting for an orthopedic intervention]. / Fyra år i operationskön--en dyr historia. Kostnaderna för produktionsbortfallet i väntan på ortopediskt ingrepp uppgår till mångmiljonbelopp.

This study was performed in order to determine the cost to society (in terms of loss of production) of having patients on paid sick-leave while on a waiting list for elective orthopedic surgery. All patients on surgical waiting lists receiving sick-leave benefits for the same diagnosis as for the planned procedure, specifically for lumbar disc herniation, lumbar spinal stenosis, and certain knee and shoulder diagnoses (not including arthritis), were identified at two large Swedish orthopedic clinics. These diagnoses were chosen since there is evidence that surgery can reduce pain and disability and also improve work ability. The number of days on sick-leave was determined individually as was each subject's reimbursement from universal health insurance. These benefits were treated as equal to the production losses caused by their inability to work according to the so-called Human Capital Method. 159 patients on the waiting lists were on sick-leave. The average waiting time varied between one and two years for the diagnoses included. Forty-four of the patients were granted temporary or permanent disability pensions while awaiting surgery. The costs for paid sick-leave together with future costs for those granted permanent disability pensions were almost 90 million SEK (almost 90 million USD). This amount corresponded to the cost of more than 2000 disc operations or more than 1000 total hip replacements. Instead of being spent on sick-leave this money ought to be used to shorten the waiting time for surgery.

Unintentional forces developed during isometric test of the shoulder.

OBJECTIVE: To study unintentional, spontaneous forces developed during isometric shoulder strength testing. DESIGN: An experimental study. BACKGROUND: During torque measurements, subjects may apply forces in directions other than requested, thereby obscuring the interpretation of the results. METHODS: A shoulder strength test was performed with a strength test device permitting measurements of force in the requested direction as well as perpendicular to it. Nine fishermen and nine welders performed isometric abduction and elevation with the arm held in various angles. Moreover four rotational postures were investigated. RESULTS: Spontaneous force deviations from requested direction were found in almost all posture tested, with errors--defined as 100 times the ratio of the magnitude of intentional torque to the magnitude of unintentional (erroneous) torque generated perpendicular to it--of more than 30% found for some postures. Abduction in 45 degrees horizontal flexion was better controlled than abduction in 90 degrees horizontal flexion. Detailed analysis indicated some groupwise differences between fishermen and welders. Also pairwise comparison of handiness indicated some differences. CONCLUSIONS: Considerable deviations from requested direction of action can arise during strength tests. Thus, one must either monitor these deviations or minimize them by a proper design of the examination to get relevant data. As the error can differ between certain subject categories depending on posture this indicate a new tool for discriminating between musculo-skeletal problems. RELEVANCE: Muscle strength devices must be used with care as their measurement setups may mask the truce muscle action of the patients.