Jeffrey G. Jarvik

Trends, Major Medical Complications, and Charges Associated with Surgery for Lumbar Spinal Stenosis in Older Adults

CONTEXT In recent decades, the fastest growth in lumbar surgery occurred in older patients with spinal stenosis. Trials indicate that for selected patients, decompressive surgery offers an advantage over nonoperative treatment, but surgeons often recommend more invasive fusion procedures. Comorbidity is common in older patients, so benefits and risks must be carefully weighed in the choice of surgical procedure. OBJECTIVE To examine trends in use of different types of stenosis operations and the association of complications and resource use with surgical complexity. DESIGN, SETTING, AND PATIENTS Retrospective cohort analysis of Medicare claims for 2002-2007, focusing on 2007 to assess complications and resource use in US hospitals. Operations for Medicare recipients undergoing surgery for lumbar stenosis (n = 32,152 in the first 11 months of 2007) were grouped into 3 gradations of invasiveness: decompression alone, simple fusion (1 or 2 disk levels, single surgical approach), or complex fusion (more than 2 disk levels or combined anterior and posterior approach). MAIN OUTCOME MEASURES Rates of the 3 types of surgery, major complications, postoperative mortality, and resource use. RESULTS Overall, surgical rates declined slightly from 2002-2007, but the rate of complex fusion procedures increased 15-fold, from 1.3 to 19.9 per 100,000 beneficiaries. Life-threatening complications increased with increasing surgical invasiveness, from 2.3% among patients having decompression alone to 5.6% among those having complex fusions. After adjustment for age, comorbidity, previous spine surgery, and other features, the odds ratio (OR) of life-threatening complications for complex fusion compared with decompression alone was 2.95 (95% confidence interval [CI], 2.50-3.49). A similar pattern was observed for rehospitalization within 30 days, which occurred for 7.8% of patients undergoing decompression and 13.0% having a complex fusion (adjusted OR, 1.94; 95% CI, 1.74-2.17). Adjusted mean hospital charges for complex fusion procedures were US

Diagnostic Evaluation of Low Back Pain with Emphasis on Imaging

80,888 compared with US

Treatment With Tissue Plasminogen Activator and Inpatient Mortality Rates for Patients With Ischemic Stroke Treated in Community Hospitals

23,724 for decompression alone. CONCLUSIONS Among Medicare recipients, between 2002 and 2007, the frequency of complex fusion procedures for spinal stenosis increased while the frequency of decompression surgery and simple fusions decreased. In 2007, compared with decompression, simple fusion and complex fusion were associated with increased risk of major complications, 30-day mortality, and resource use.

Three-Year Incidence of Low Back Pain in an Initially Asymptomatic Cohort : Clinical and Imaging Risk Factors

Low back pain is a pervasive problem that affects two thirds of adults at some time in their lives. It ranks among the top 10 reasons for visits to internists (1, 2) and is the most common and expensive reason for work disability in the United States (3). Most often, back pain is benign and self-limited. However, it is occasionally the presenting symptom of such systemic diseases as cancer or infection. Some causes of back pain, especially those with neurologic symptoms, are surgically remediable. Thus, the major diagnostic task is to distinguish the 95% of patients with simple back pain from the 5% with serious underlying diseases or neurologic impairments. Differential Diagnosis The differential diagnosis of low back pain can be divided into mechanical causes (no primary inflammatory or neoplastic cause), visceral causes (no primary involvement of the spine), and all others (4) (Table 1). A definitive diagnosis cannot be made in as many as 85% of patients because symptoms and pathologic changes are not closely associated (9). Many cases of uncomplicated low back pain are assumed to result from muscle sprains and strains, ligamentous injuries, and spinal degenerative changes. Table 1. Differential Diagnosis of Low Back Pain Disc herniation with nerve root compression or irritation is the most common cause of neurologic abnormalities. Spinal stenosis may also be associated with leg symptoms and neurologic abnormalities, often involving both sides of the body and multiple nerve roots. Spinal instability (in the absence of fractures or spondylolisthesis) remains a controversial diagnosis. It is often identified by the finding of vertebral slippage on flexion radiographs (10). The prevalence of spinal instability in asymptomatic persons is unclear, as is the degree to which this condition causes pain. The diagnosis of internal disc disruption, identified by provocative discography (injection of contrast material into the disc with simultaneous assessment of pain), is even more controversial. Discography frequently generates pain in asymptomatic adults (11), and symptoms attributed to internal disc disruption often improve spontaneously (12). The true significance and appropriate management of this condition remain unclear. When the precise anatomic sources of pain cannot be determined, early diagnostic evaluation that focuses on three basic questions is useful: 1) Is there underlying systemic disease? 2) Is there neurologic impairment that might require surgical evaluation? 3) Is social or psychological distress amplifying or prolonging the pain? (7). For most young or middle-aged adults, these questions can be answered on the basis of history and physical examination alone; diagnostic testing is infrequently required. Pretest Probability of Disorders that Cause Back Pain Systemic Diseases In primary-care settings, about 0.7% of patients with back pain have metastatic cancer. About 0.01% have spinal infections, and 4% have osteoporotic compression fractures. Only about 0.3% have ankylosing spondylitis (7). Taking a history is more useful than physical examination in screening for underlying malignancy, at least in the early stages (Table 2) (7, 10). A history of cancer mandates further evaluation. The most common sources of metastatic cancer are the breast, lung, and prostate; these areas should be examined when cancer is suspected. Table 2. Estimated Accuracy of the History in the Diagnosis of Spinal Diseases That Cause Low Back Pain Spinal infections are usually acquired hematogenously from other sites. Common underlying infections are related to injection drug use, urinary tract infection, or skin infection. Compression fractures in older adults usually result from osteoporosis. Only about 30% of such patients have identifiable trauma. The prevalence of this condition is substantially associated with race: African-American and Mexican-American women have 25% fewer compression fractures than white women (18). Ankylosing spondylitis and other inflammatory spondyloarthropathies occur rarely, and the predictive value of positive findings is low (19). Tests of sacroiliac joint tenderness are poorly reproducible and inaccurate in distinguishing ankylosing spondylitis from mechanical spinal conditions (7). Neurologic Impairment The first clinical clue to neurologic impairment usually is a history of sciatica: sharp pain radiating down the posterior or lateral aspect of the leg, often associated with numbness or paresthesia. Pain radiating below the knee as opposed to pain limited to the buttocks or thigh is more likely to represent true radiculopathy. Pain is sometimes aggravated by coughing, sneezing, or the Valsalva maneuver. The most common cause of sciatica is a herniated intervertebral disc, which occurs most often between the ages of 30 and 55 years. Imaging identifies herniated discs in many persons with low back pain (20-23); thus, only a minority of these discs are therapeutically important (14, 24). More than 95% of clinically important lumbar disc herniations occur at the two lowest discs and involve the L5 or S1 nerve roots. Thus, the most common neurologic syndromes are weakness of the ankle and great toe dorsiflexors and sensory loss along the medial foot (L5), or weakness of ankle plantar flexion, diminished ankle reflex, and sensory loss along the lateral aspect of the foot (S1) (Table 2). Combinations of findings have not been evaluated but are probably more useful than any single finding (7, 25). Spinal stenosis may be caused by bone (for example, facet hypertrophy), soft tissue (for example, bulging disc or thickened ligamentum flavum), or both. Like other degenerative conditions, it is most common in older adults. As many as 20% of asymptomatic adults age 60 years or older have imaging evidence of spinal stenosis (20), but the prevalence of symptomatic stenosis is unknown. The classic symptom of spinal stenosis is neurogenic claudication, which is leg pain that mimics arterial claudication (26). Compared with arterial claudication, neurogenic claudication is more likely to occur simply with standing. Numbness and tingling are common, and symptoms often worsen with coughing or sneezing. Perhaps the most useful finding is a history of no pain when the patient is seated with the spine flexed (Table 2) (16). Another neurologic condition is the cauda equina syndrome, which may result from a massive midline disc hernia that causes compression of the cauda equina. It is a surgical emergency that requires immediate referral. The syndrome represents only 1% to 2% of lumbar disc herniations that require surgery. Prevalence among all patients with low back pain has been estimated at 0.0004 (7). The most consistent symptom is urinary retention. Unilateral or bilateral sciatica, sensory and motor deficits, and abnormal straight-leg raising are common. Sensory deficits over the buttocks, thighs, and perineal region (saddle anesthesia) and reduced anal sphincter tone occur in about 75% of patients (7). Diagnostic Test Description To review the diagnostic imaging literature, we performed a MEDLINE search of articles published between January 1966 and September 2001. Methods used for the search strategy are available in the Appendix. We sequentially reviewed all article titles (n = 1468). We then read the abstracts of 568 articles that seemed pertinent and the full text of 150 of these 568 articles. The authors and their affiliations were masked. Disagreements on whether particular articles should be included (approximately 15% of total articles) were settled by consensus. The data for this article were collected only from articles in the MEDLINE search. In primary care settings, the most common spine imaging tests are plain radiography, computed tomography (CT), magnetic resonance imaging (MRI), and bone scanning. Other tests (myelography, discography, and positron emission tomography) are usually ordered by specialists before surgical intervention and were not reviewed. The estimated diagnostic accuracy of these imaging techniques are given in Table 3. Table 3. Estimated Accuracy of Imaging Technique for Lumbar Spine Conditions Biases were common in the studies reviewed. The most common biases were failure to apply a single reference test to all patients, test review bias (study test was reviewed with knowledge of the final diagnosis), diagnosis review bias (determination of the final diagnosis was affected by the study test), and spectrum bias (only severe cases of disease were included). Most studies had several potential biases, and estimates of sensitivity and specificity must be considered imprecise. Plain Radiography Overview Low cost and ready availability make plain radiography the most common spinal imaging test. Several investigators (27, 28) have recommended discontinuing use of routine oblique and spot lateral views because they do not provide adequate clinically relevant findings. This position was adopted in the Agency for Health Care Policy and Research (AHCPR) guidelines (29). The anteroposterior and lateral views demonstrate alignment, disc and vertebral body height, and gross assessment of bone density and architecture; however, soft tissue structures are not evaluated extensively by these views. Oblique views show the pars interarticularis in profile and are useful for diagnosing spondylolysis when clinical evidence exists. Other special views include flexion and extension views to assess instability and angled views of the sacrum to assess sacroiliac joints for ankylosing spondylitis. Lumbar radiography may be harmful because it exposes the gonads to ionizing radiation, especially with oblique views or repeated exposures. This is a particular concern for younger female patients. The radiation exposure of oblique views is double the exposure of standard views, which alone are equivalent to the female gonadal radiation of daily chest radiography for several years (30-32). Plain radiography ide

A multicenter in vivo proton-MRS study of HIV-associated dementia and its relationship to age.

Background and Purpose— Most analyses of intravenous tissue plasminogen activator (IV tPA) use for acute stroke in routine practice have been limited by sample size and generally restricted to patients treated in large academic medical facilities. In the present study, we sought to estimate among community hospitals the use of IV tPA and to identify factors associated with the use of IV tPA and inpatient mortality. Methods— We evaluated a retrospective cohort of 23 058 patients with ischemic stroke from 137 community hospitals. Results— Three hundred sixty-two (1.6%) patients were treated with IV tPA, and 9.9% of those patients died during the hospitalization period. In 35.0% of the hospitals, no patients were treated with IV tPA, whereas 14.6% of hospitals treated ≈3.0% with IV tPA. After control for multiple factors, younger patients, more severely ill patients (OR 2.02, 95% CI 1.36 to 3.01), and patients treated in rural hospitals (OR 1.80, 95% CI 0.99 to 3.26) were more likely to receive IV tPA, whereas black patients were less likely (OR 0.54, 95% CI 0.31 to 0.95). There also was a trend showing that women were less likely to receive IV tPA (OR 0.84, 95% CI 0.69 to 1.03). Factors associated with an increased odds of inpatient mortality included receipt of IV tPA among men (OR 2.81, 95% CI 1.72 to 4.58) and increased age. Black patients were 27% less likely to die during hospitalization (95% CI 0.60 to 0.90). Conclusions— In this large, retrospective evaluation of community hospital practice, the use IV tPA and inpatient mortality rates among IV tPA–treated patients were consistent with those of other studies. The likelihood of receiving IV tPA varies by race, age, disease severity, and possibly gender. These factors may influence mortality rates.

Systematic Literature Review of Imaging Features of Spinal Degeneration in Asymptomatic Populations

Study Design. Prospective cohort study of randomly selected Veterans Affairs out-patients without baseline low back pain (LBP). Objective. To determine predictors of new LBP as well as the 3-year incidence of magnetic resonance imaging (MRI) findings. Summary of Background Data. Few prospective studies have examined clinical and anatomic risk factors for the development of LBP, or the incidence of new imaging findings and their relationship to back pain onset. Methods. We randomly selected 148 Veterans Affairs out-patients (aged 35 to 70) without LBP in the past 4 months. We compared baseline and 3-year lumbar spine MRI. Using data collected every 4 months, we developed a prediction model of back pain-free survival. Results. After 3 years, 131 subjects were contacted, and 123 had repeat MRI. The 3-year incidence of pain was 67% (88 of 131). Depression had the largest hazard ratio (2.3, 95% CI = 1.2–4.4) of any baseline predictor of inci-dent back pain. Among baseline imaging findings, central spinal stenosis and nerve root contact had the highest, though nonsignificant, hazard ratios. We did not find an association between new LBP and type 1 endplate changes, disc degeneration, annular tears, or facet degeneration. The incidence of new MRI findings was low, with the most common new finding being disc signal loss in 11 (9%) subjects. All five subjects with new disc extrusions and all four subjects with new nerve root impingement had new pain. Conclusion. Depression is an important predictor of new LBP, with MRI findings likely less important. New imaging findings have a low incidence; disc extrusions and nerve root contact may be the most important of these findings.

The utility of magnetic resonance imaging in evaluating peripheral nerve disorders

OBJECTIVE Differences in diagnostic criteria and methods have led to mixed results regarding the metabolite pattern of HIV-associated brain injury in relation to neurocognitive impairment. Therefore, a multicenter MRS consortium was formed to evaluate the neurometabolites in HIV patients with or without cognitive impairment. METHODS Proton magnetic resonance spectroscopy (MRS) at short-echo time (30 ms) was assessed in the frontal white matter, basal ganglia, and parietal cortex of 100 HIV patients [61 with AIDS dementia complex (ADC) and 39 neuroasymptomatic (NAS)] and 37 seronegative (SN) controls. RESULTS Compared to SN, NAS had higher glial marker myoinositol-to-creatine ratio (MI/Cr) in the white matter (multivariate analyses, adjusted P=0.001), while ADC showed further increased MI/Cr in the white matter and basal ganglia (both P<0.001), and increased choline compounds (Cho)/Cr in white matter (P=0.04) and basal ganglia (P<0.001). Compared to NAS, ADC showed a reduction in the neuronal marker N-acetyl compound (NA)/Cr in the frontal white matter (P=0.007). CSF, but not plasma, viral load correlated with MI/Cr and Cho/Cr in white matter and NAA/Cr in parietal cortex. HIV infection and aging had additive effects on Cho/Cr and MI/Cr in the basal ganglia and white matter. CONCLUSIONS The results suggest that glial activation occurs during the NAS stages of HIV infection, whereas further inflammatory activity in the basal ganglia and neuronal injury in the white matter is associated with the development of cognitive impairment. Aging may further exacerbate brain metabolites associated with inflammation in HIV patient and thereby increase the risk for cognitive impairment.

MR nerve imaging in a prospective cohort of patients with suspected carpal tunnel syndrome

This meta-analysis of the literature reveals that imaging findings of spine degeneration are present in high proportions of asymptomatic individuals, increasing with age. Many imaging-based degenerative features are likely part of normal aging and unassociated with pain. BACKGROUND AND PURPOSE: Degenerative changes are commonly found in spine imaging but often occur in pain-free individuals as well as those with back pain. We sought to estimate the prevalence, by age, of common degenerative spine conditions by performing a systematic review studying the prevalence of spine degeneration on imaging in asymptomatic individuals. MATERIALS AND METHODS: We performed a systematic review of articles reporting the prevalence of imaging findings (CT or MR imaging) in asymptomatic individuals from published English literature through April 2014. Two reviewers evaluated each manuscript. We selected age groupings by decade (20, 30, 40, 50, 60, 70, 80 years), determining age-specific prevalence estimates. For each imaging finding, we fit a generalized linear mixed-effects model for the age-specific prevalence estimate clustering in the study, adjusting for the midpoint of the reported age interval. RESULTS: Thirty-three articles reporting imaging findings for 3110 asymptomatic individuals met our study inclusion criteria. The prevalence of disk degeneration in asymptomatic individuals increased from 37% of 20-year-old individuals to 96% of 80-year-old individuals. Disk bulge prevalence increased from 30% of those 20 years of age to 84% of those 80 years of age. Disk protrusion prevalence increased from 29% of those 20 years of age to 43% of those 80 years of age. The prevalence of annular fissure increased from 19% of those 20 years of age to 29% of those 80 years of age. CONCLUSIONS: Imaging findings of spine degeneration are present in high proportions of asymptomatic individuals, increasing with age. Many imaging-based degenerative features are likely part of normal aging and unassociated with pain. These imaging findings must be interpreted in the context of the patients clinical condition.

Memantine and HIV-associated cognitive impairment: A neuropsychological and proton magnetic resonance spectroscopy study

The evaluation of peripheral nerve injuries has traditionally relied primarily on information gained from the clinical history, physical examination, and electrodiagnostic testing. Taken together, all of this clinical and diagnostic information often allows one to determine the location and severity of the underlying peripheral nerve problem. However, it may not be sufficient in diagnosing a focal entrapment neuropathy superimposed upon a more generalized peripheral neuropathy; localizing a focal lesion along a long segment of nerve which may be difficult to assess accurately with electrodiagnostic sutdies; distinguishing early between an axonotmetic grade of injury, which can recover through axonal regeneration, and a neurotmetic grade which cannot and therefore may benefit from a surgical exploration and repair procedure; and noninvasively diagnosing and determining the surgical resectability of peripheral nerve mass lesions such as tumors. The goal of this review is to illustrate how standard and evolving magnetic resonance imaging techniques can provide additional information in dealing with some of these problems.

Effectiveness of vertebroplasty using individual patient data from two randomised placebo controlled trials: meta-analysis

Objectives To evaluate the reliability and diagnostic accuracy of high-resolution MRI of the median nerve in a prospectively assembled cohort of subjects with clinically suspected carpal tunnel syndrome (CTS). Methods The authors prospectively identified 120 subjects with clinically suspected CTS from five Seattle-area clinics. All subjects completed a hand-pain diagram and underwent a standardized nerve conduction study (NCS). The reference standard for determining CTS status was a classic or probable hand pain diagram and NCS with a difference >0.3 ms between the 8-cm median and ulnar peak latencies. Readers graded multiple imaging parameters of the MRI on four-point scales. The authors also performed quantitative measurements of both the median nerve and carpal tunnel cross-sectional areas. NCS and MRI were interpreted without knowledge of the other study or the hand pain diagram. Results Intrareader reliability was substantial to near perfect (kappa = 0.76 to 0.88). Interreader agreement was lower but still substantial (kappa = 0.60 to 0.67). Sensitivity of MRI was greatest for the overall impression of the images (96%) followed by increased median nerve signal (91%); however, specificities were low (33 to 38%). The length of abnormal signal on T2-weighted images was significantly correlated with nerve conduction latency, and median nerve area was larger at the distal radioulnar joint (15.8 vs 11.8 mm2) in patients with CTS. A logistic regression model combining these two MR variables had a receiver operating characteristic area under the curve of 0.85. Conclusions The reliability of MRI is high but the diagnostic accuracy is only moderate compared with a research-definition reference standard.