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STUDY DESIGN A prospective multicenter investigational device exempt trial is underway evaluating a novel conformable mesh interbody fusion device in subjects undergoing single-level fusion for degenerative disc disease. Patients meeting inclusion and exclusion criteria were offered enrollment. There is no comparative group in this study. OBJECTIVE Establish the short and long-term safety and effectiveness of a novel conformable mesh interbody fusion device in subjects undergoing single-level fusion for degenerative disc disease unresponsive to conservative care. SUMMARY OF BACKGROUND DATA Transforaminal lumbar interbody fusion remains a critical procedure for patients with degenerative lumbar disc disease. Increasingly minimally invasive techniques have been proposed to minimize muscle dissection and tissue damage with the goal of minimizing pain and length of stay. METHODS One hundred two subjects were enrolled across 10 sites. Ninety nine subjects remained available for follow-up at 12-months. Physical evaluations/imaging were performed serially through 12-months. Validated assessment tools included 100 mm visual analogue scale (VAS) for pain, Oswestry Disability Index (ODI) for function, and computerized tomography scan for fusion. Independent committees were used to identify adverse events and for assessment of radiographic fusion. RESULTS Reductions in low back pain (LBP)/leg pain and improvements in functional status occur early and are maintained through 12-month follow-up. Mean VAS-LBP change from baseline to 6-weeks post-op (-46 mm) continued to improve through 12 months (-51 mm). Similar trends were observed for leg pain. Mean ODI change from baseline to 6 weeks post-op (-17) was almost doubled by 12 months (-32). Fusion rates at 12-months are high (98%). No device-related serious adverse events have occurred. CONCLUSION 12-month outcomes demonstrated excellent patient compliance and positive outcomes for pain, function, fusion, and device safety. Clinical improvements were observed by 6-weeks post-op and appear durable up to 1 year later. A novel mesh interbody device may provide an alternative means of interbody fusion that reduces connective tissue disruption.Level of Evidence: 3.

Study design A case-control study of the Trp2/3 alleles of COL9A2/3 genes and their correlation with occurrence of Lumbar disc disease (DDD) as phenotyped by magnetic resonance imaging. Objective To establish a better understanding of relationship between presence of said alleles and occurrence of DDD in South-Western Iranian population. Summary of background data A number of genetic predisposing factors have been identified in elevating the risk of developing DDD. Specifically, the Trp2 and Trp3 alleles of COL9A2 and COL9A3 genes have been suggested as DDD risk variants. Methods A total of 108 patients (mean age = 41±11.8 yrs, range = 20-66 yrs) with 57 controls (mean age = 35±10.0 yrs, range = 20-58 yrs) participated in the study. The frequency of G/A polymorphism in COL9A2 gene on location 326 on chromosome 1 and G/A/C/ or T polymorphism in 103 location of COL9A3 gene on chromosome 20 was assessed using a PCR short-primer technique. Outcome measure was defined as presence of DDD on MRI. Odds ratios (OR) and 95% confidence intervals (CI) were used to assess the likelihood of DDD given occurrence of Trp2(3). Results Each allele was present in both patients and controls. The Trp2 allele was positive in 28.5% of individuals (31.5% of patients; 22.8% of controls), OR 1.55 (0.71-3.56). The Trp3 allele, the frequency was 23.6% in all patients (26.9% patients; 17.5% controls), OR 1.72 (0.73-4.33). We observed a 5.8-fold increase in the odds of DDD in males when the Trp3 allele was present, OR 5.83 (1.09-9.98), P = 0.0273. Conclusion Both Trp2 and Trp3 alleles occurred more frequently compared with other studied ethnicities. The sampled Iranian population exhibited a similar Trp2 frequency to a Southern Chinese population, and Trp3 occurrence to Finnish and Greek population. We found that male patient were much more likely to develop DDD when Trp 3 was present. Level of evidence N/A.

Prospective cohort study.To study biomechanical factors in relation to symptomatic lumbar disc disease.The importance of biomechanical factors in lumbar disc disease has been questioned in the past decade and knowledge from large prospective studies is lacking.The study basis is a cohort of 263,529 Swedish construction workers who participated in a national occupational health surveillance program from 1971 until 1992. The workers' job title, smoking habits, body weight, height, and age were registered at the examinations. The occurrence of hospitalization due to lumbar disc disease from January 1, 1987, until December 31, 2003, was collected from a linkage with the Swedish Hospital Discharge Register.There was an increased risk for hospitalization due to lumbar disc disease for several occupational groups compared with white-collar workers and foremen. Occupational groups with high biomechanical loads had the highest risks, for example, the relative risk for concrete workers was 1.55 (95% confidence interval [CI], 1.29-1.87). A taller stature was consistently associated with an increased risk. The relative risk for a man of 190- to 199-cm height was 1.55 (95% CI, 1.30-1.86) compared with a man being 170- to 179-cm height. Body weight and smoking were also risk factors, but weaker than height. Workers in the age span of 30 to 39 years had the highest relative risk (RR = 1.87; 95% CI, 1.58-2.23) compared with those aged 20 to 29 years, whereas men aged 60 to 65 years had a lower risk (RR = 0.86; 95% CI, 0.68-1.09).This study indicates that factors increasing the load on the lumbar spine are associated with hospitalization for lumbar disc disease. Occupational biomechanical factors seem to be important, and a taller stature was consistently associated with an increased risk.

Study design An in vitro study using rabbit intervertebral disc tissue and disc cells. Objective To evaluate the effects of disc degeneration, age, and bone morphogenetic proteins-2 (BMP-2) on cartilage intermediate layer protein (CILP) expression and elucidate the molecular mechanism by which BMP-2 regulates CILP expression. Summary of background data CILP is implicated in several diseases that affect cartilage. The CILP polymorphism acts as a modulator of lumbar disc disease susceptibility. However, regulation of the CILP gene in disc tissue remains poorly understood. Methods Intact discs from young rabbits were punctured to induce disc degeneration. These young rabbits and other older rabbits were used to measure the expression of CILP, proteoglycan, and collagen II using Western blot and real-time PCR. Primary disc cells from the rabbits were treated with rhBMP-2, or siRNAs, and the gene expression was analyzed by Western blot and real-time PCR. The activity of the CILP promoter was measured by using the Dual Luciferase Reporter Assay System. Results Our study demonstrates that the intervertebral disc expresses significant levels of CILP and that the expression of CILP increases substantially with increasing age and disc degeneration. In contrast, the expression of proteoglycan and collagen II decrease with increasing age and disc degeneration. BMP-2 induces the expression of CILP protein and stimulates the activity of the CILP promoter in rabbit primary disc cells. The induction of CILP by BMP-2 can be augmented with age. Knockdown of Smad1 by siRNA abolishes the stimulatory effects of BMP-2 on CILP expression in the primary disc cells. Conclusion Our data demonstrate that disc degeneration, age, and BMP-2 are regulators of the CILP gene. BMP-2 induces CILP expression by activating the Smad1 signal pathway.

Study design Cohort study. Objective To examine the association between self-reported physical workload and risk of herniated lumbar disc disease (HLDD) in a long-term follow-up of men without a history of back disorders at baseline. Summary of background data Heavy physical workload is considered a risk factor for HLDD, but the issue is not definitively settled. Methods The Copenhagen Male Study is a prospective cohort study established in 1970 to 1971. At baseline, 5245 men answered a questionnaire about history of back disease and physical workload. Psychosocial working conditions, lifestyle, social class, and measured height and weight were included as potential confounders. Information about hospitalization due to HLDD was obtained from the National Hospital Register covering the period from 1977 to 2003. Hazard ratios were calculated by Cox proportional hazard regression model. Results Among 3833 men without back disease history at baseline, the strongest predictor of hospitalization for HLDD was frequent strenuous physical activity at work; compared with unexposed, the hazard ratio with 95% confidence interval was 3.90 (1.82-8.38). Also, body height was a significant predictor, whereas body weight was only insignificantly associated with HLDD. Conclusion Among men without history of back disease reporting of frequent exposure to strenuous physical activity at work was a strong risk factor for later hospitalization due to HLDD.

STUDY DESIGN: Cross-sectional. OBJECTIVES: To evaluate the interaction between the COL9A3 gene polymorphism and persistent obesity in relation to lumbar disc degeneration. SUMMARY OF BACKGROUND DATA: Obesity has been suggested to be a risk factor for disc degeneration. There is some indication for an association between collagen IX genes and lumbar disc disease characterized by sciatica. However, the interaction between those factors in their influences on the risk of disc degeneration has not been studied. METHODS: Blood samples from 135 middle-aged men who had undergone magnetic resonance imaging (MRI) of the lumbar spine were analyzed for the presence of an arginine to tryptophan change in the COL9A3 gene (Trp3 allele). The men represented three occupations: 41 were machine drivers, 42 were carpenters, and 52 were office workers. The discs L2/L3-L5/S1 were evaluated on MRI, using decreased signal intensity of the nucleus pulposus, posterior disc bulges, and decreased disc height as signs of disc degeneration. Based on self-reports on body height and weight currently and at the age of 25 years, obesity history was classified as no obesity, persistent obesity, and other. Rothman's synergy index was used as a measure of interaction between two factors. RESULTS: The Trp3 allele and persistent obesity acted synergistically to increase the risk of dark nucleus pulposus, posterior disc bulge, and decreased disc height at L4/L5; of multilevel posterior disc bulges; and of decreased disc height. From 45% to 71% of disc degeneration among persistently obese individuals with the Trp3 allele could be attributed to the synergism of these two factors. CONCLUSION: The effect of obesity on lumbar disc degeneration seems to be modified by the collagen IX gene polymorphism, so that people who carry the Trp3 allele are at increased risk if they are persistently obese.

Study Design. Retrospective literature review. Objectives. To review the data on the clinical efficacy of intradiscal electrothermal annuloplasty found at this writing in the peet-reviewed literature to date, to discuss the methodologic strengths and flaws of the studies, to discuss the pitfalls of clinical study designs, to emphasize the need for prospective randomized studies and for increased basic sclence investigation. of Background Data. Studies published or presented at peer-reviewed societies concerning the clinical efficacy of intradiscal electrothermal annuloplasty are reviewed, including baokground studies on deafferentation and application of thermal energy to alter biomechanical and structural properties. A proposal for future investigations is presented. Methods, Background dats from intracapsular annuloptasty highlighting the safety and efficacy of intradiscal electrothermal annulopiasty are presented. Current studies on this procedure, including those in the National Registry are reviewed. All the studies share a common study design: prospective cohert with histerical or noninterventional groups used as contrels. The patients reviewed are similar. All have nonradicular low back pain of at least 3 months duration, failed conservative care, normal neurologic examination, and MRI showing only nondagenerative disc diseass and positive concordant discography. All the patients underwant intradiscal electrothermal annuloplasty lesion at one or two levels according to standard protocols. Follow-up evaluation was performed at various intervals up to 2 years. All the studies used data from a visual analog scale, with most using the Short Form 36 (SF 38) as outcome instruments. Results. The reported follow up periods for the studies ranged from 6 months to 2 years. Three published studies, one with a 6-month follow-up period and two with a 1-year follow-up period, were published in the peer-reviewed literature. Two recent reports presented to the North American Spine Society were reviewed. a study of patients on a manufacturer sponsored registry with a 1-year follow-up period and a multicenter prospective cohort study of 75 patients in an intent-to-treat group, with a 1-year foliow-up period. Using the 7-point criteria of Deyo et al, all the studies suggested a positive effect of treatment, with a decrease in visual analog scale ratings and improvement in SF-38 scales, particularty those for physical function and bodily pain. Conclusions. The studies published so far suggest that the pain resulting from lumbar disc disease may be diminished by intradiscal electrothermal annuloplasty. All these studies project a positive therapeutic effect. However, all the studies suffer from the same methodolgic flaws, A prospactive cohort design or a nonrandomized prospective design is used with a biased control. The acientific validity of various study designs is discussed. and a randomized prospective study is recommended. Additionally, more investigation into the basic science of the action of intradiscal electrothermal annuioplasty is required.

Study design Meta-analysis to collect all the relevant studies to date to further investigate whether or not the COL9A2 gene rs12077871, rs12722877, and rs7533552 polymorphism are associated with susceptibility to lumbar disc disease (LDD). Objective The aim of this study was to assess the association between the COL9A2 gene rs12077871, rs12722877, and rs7533552 and LDD. Summary of background data LDD is a common musculoskeletal disease with strong genetic determinants. COL9A2 encodes the α2 (IX) chain of type IX collagen, which is the major collagen component of the hyaline cartilage. Growing numbers of studies have revealed the association between COL9A2 polymorphisms and susceptibility to LDD. However, those studies have yielded contradictory results. Methods Data were collected from the following electronic databases: PubMed, Web of Knowledge, and China National Knowledge Infrastructure, with the last report up to November 30, 2013. The odds ratio (OR) and 95% confidence interval (CI) were used to assess the strength of association under the allelic genetic model. We summarized the data on the association between COL9A2 rs12077871, rs12722877, and rs7533552 polymorphism and LDD in the overall studies. Results Nine case-control studies, including 1522 LDD cases and 1646 controls, were identified. The results indicated that the rs12077871, rs12722877, and rs7533552 variants in COL9A2 were not associated with LDD (rs12077871: C vs. T, OR = 0.541, 95% CI = 0.256-1.147, P = 0.109; rs12722877: C vs. G, OR = 1.199, 95% CI = 0.992-1.448, P = 0.06; rs7533552: A vs. G, OR = 0.993, 95% CI = 0.815-1.069, P = 0.320). Furthermore, the Egger test and the Begg funnel plot did not show any evidence of publication bias. Conclusion Our results suggest that the COL9A2 rs12077871, rs12722877, and rs7533552 polymorphisms may not be associated with LDD. More studies based on larger sample sizes and homogeneous samples of patients with LDD are needed to confirm these findings. Level of evidence 2.

STUDY DESIGN Two cases of lumbar disc herniation with alkaptonuria are presented. OBJECTIVES To present a probable clinical course of lumbar disc herniation with alkaptonuria, a rare metabolic disease. SUMMARY OF BACKGROUND DATA Although lumbar disc disease is a common clinical occurrence in alkaptonuria, lumbar disc surgery is needed rarely in this disease. A patient with alkaptonuria without ochronotic signs is also rarely seen. METHODS The cause, clinical presentation, diagnostic techniques and treatment of alkaptonuria with lumbar disc disease are reviewed. RESULTS The symptoms of the patients disappeared after surgery, and there were no symptoms on follow-up. CONCLUSION Alkaptonuria frequently occurs in association with lumbar disc disease. In patients with no other signs of alkaptonuria or ochronosis, early detection of the disease is important to treat involvement of other systems (e.g., cardiovascular and urinary).

Study design A case report. Objective To demonstrate a case of intradural lumbar disc herniation including imaging studies, intraoperative imaging, and an intraoperative video. Summary of background data The first case of lumbar intradural disc herniation was reported as early as 1942; since then more than 150 cases have been reported, mostly in the lumbar spine. Gadolinium-enhanced magnetic resonance image (MRI) is considered the "gold standard" for diagnosing this entity, although it is rarely performed routinely in lumbar disc disease and diagnosis is often made intraoperatively. Methods A 70-year-old man presented to the emergency department as a referral complaining of lower back pain, loss of sensation in the right thigh, and difficulty walking. On examination, he showed uneven gait, right-sided foot drop (1/5), hypesthesias in the right inguinal area and ventral thigh, and a positive straight leg raise test on the right. Anal sphincter tone was within normal limits. A magnetic resonance image of the lumbar spine showed a large mediolateral herniated disc at L3-L4, with caudal displacement and unclear signal changes intradurally. Results Intraoperatively, the herniated disc was found upon opening the dural sac. Conclusion Intradural disc herniations are a rare entity. The opening and inspection of the dural sack should be considered when the correct spinal level can be confirmed and insufficient herniated disc material can be visualized extradurally.

Study Design. Description of a new operative technique for anterior lumbar and lumbosacral fusion using an anterior extraperitoneal approach optimized by video assistance. Objectives. To propose a less invasive technique for anterior lumbar fusion with low-grade morbidity. Summary of Background Data. Either anterior transperitoneal or anterolateral extraperitoneal approaches commonly are performed, but each involves specific drawbacks. The authors attempted to modify and simplify these approaches with the addition of retroperitonoscopy. Methods. A small, vertical 4- to 5-cm incision is made on the midline, centered on the umbilicus for the L4-L5 approach and halfway between umbilicus and public symphysis for the L5-S1 appraoch. The peritoneum is dissected from the left abdominal wall, and the anterior aspect of the spine progressively is explosed. The endoscope is introduced laterally, providing excellent visualization of the prevertebral area. A specially designed retractor allows retraction of the iliac vessels. Results. A midline anterior approach allows disc resection and grafting in a strict midline position. The extraperitoneal approach simplifies the postoperative course. Video assistance permits an approach to the spine by a short incision and facilitates the prevertebral dissection. Surgery with video assistance should be differentiated from true endoscopic surgery, which is performed under CO 2 insufflation with exclusive endoscopic vision. Conclusions. Video assistance allows for an anterior extraperitoneal approach to the lumbar spine and has the potential for lower morbidity, increasing the possibilities of anterior fusion in the management of lumbar disc disease.

Study design Survey of surgeon members of the Scoliosis Research Society. Objective To assess the prevalence of musculoskeletal disorders (MSDs) among spine surgeons. Summary of background data Spinal deformity surgery is characterized by long duration and repetitive, forceful tasks. The purpose of this study is to describe the type and prevalence of MSDs among orthopedic spine surgeons. Methods A modified version of the physical discomfort survey was sent to surgeon members of the Scoliosis Research Society via standard mail and e-mail. A total of 3 attempts to contact potential respondents were made, with 62% (561/904 × 100) responding. Mean respondent age was 54 years. Mean annual total caseload was 147, of which 62 were of spinal deformity. A total of 84% of the respondents had an active surgical practice. Results The most common self-reported diagnoses included neck pain/strain/spasm (38%, 215/561), lumbar disc herniation/radiculopathy (31%, 172/561), cervical disc herniation/radiculopathy (28%, 155/561), rotator cuff disease (24%, 134/561), varicose veins or peripheral edema (20%, 112/561), and lateral epicondylitis (18%, 99/561). For lumbar disc disease, 7.1% (40/561 × 100) and for cervical disc disease, 4.6% (26/561 × 100) of spine surgeons underwent surgery. Among active spine surgeons, multiple linear regression analysis revealed that total caseload correlated with neck pain (P = 0.01) and lower extremity edema (P = 0.03), while the number of deformity cases correlated with wrist pain (P = 0.003) and hand pain (P = 0.03). Age was correlated with shoulder (P = 0.03), elbow (P = 0.04), and hand pain (P = 0.02). Number of years in practice did not correlate with MSDs. Conclusion Compared with disease estimates in the general population, spine surgeons have a higher prevalence of MSDs. Our cohort underwent surgical intervention for lumbar (7.1%) and cervical (4.6%) disc disease at rates far exceeding disease estimates in the general population. Increased awareness among spine surgeons may lead to earlier treatment and, ultimately, enhanced preventive measures.

The role of facet tropism (asymmetry) in the pathogenesis of degenerative disc disease is unknown, and several conflicting reports have been published. We studied this association using CT/discography performed at 324 lumbar levels (108 patients). The stage of disc degeneration as well as the patient's pain response upon discographic injection were scored using a standardized protocol. The facet angles were measured directly from the axial CT/discographic images and defined, in each case, as the angle formed by the facet orientation with respect to the midsagittal plane. The facet tropism angle was defined as the difference between the left and right facet angles at each disc level. The mean and standard deviation (SD) of the tropism angles were calculated. From this calculation, each pair of facet joints was classified as symmetric (within 1 SD of the mean), moderately asymmetric (between 1 and 2 SD), or severely asymmetric (beyond 2 SD of the mean). There were no differences in degree of disc degeneration or pain response with respect to the facet tropism. The total facet angle was also studied. The total facet angle was greater at the more caudal levels. The total angle size was not associated, however, with disc degeneration or pain provocation. These findings do not support the hypothesis that there is an association between facet tropism and degenerative lumbar disc disease.

This study was undertaken to determine the correlation between awake discography findings and magnetic resonance imaging in the evaluation of symptomatic lumbar disc disease. The study included 164 consecutive patients who underwent evaluation with discography and magnetic resonance imaging for lumbar disc disease from August 1987 to September 1989. Chronic low-back pain, with or without radicular symptoms, was the presenting complaint in each case. Each patient had previously failed conservative treatment. The average age was 36 (range, 19-66 years). Magnetic resonance images were performed before discography in each case. Discography was performed with patients minimally sedated and under local anesthesia. A lateral approach was used. Magnetic resonance imaging and discography correlated in 90 cases (55%) and differed in 74 (45%). Considering disc levels, discography and magnetic resonance imaging correlated in 371 discs (80%). There were 172 normal discs and 199 abnormal discs. Of the abnormal discs, 151 (76%) reproduced symptoms. In 60 discs (13%), magnetic resonance images showed abnormal findings and the discogram normal findings. Discs levels classified as abnormal on magnetic resonance imaging demonstrated that 108 discs (37%) were asymptomatic. Magnetic resonance imaging showed normal findings and the discogram abnormal findings in 34 discs (7%), of which 21 (5%) recreated exact symptoms and 13 (2%) caused no pain. Magnetic resonance imaging is a static test and discography the only available dynamic test for disc evaluation. Awake discography is a diagnostic study that can determine which abnormal discs are symptomatic via the pain response.

Study design Case report of a 49-year-old woman with a lower thoracic disc herniation mimicking acute lumbosacral radiculopathy. Objective To describe an unusual case of thoracic disc herniation mimicking acute lumbar disc disease. Summary of background data Symptomatic thoracic disc herniation is rare and its clinical manifestations differ widely from those of cervical and lumbar disc herniations. Midline back pain and signs of spinal cord compression progressing over months or years are the predominant clinical features. Acute and subacute thoracic disc herniation occurs in less than 10% of patients, and isolated root pain is unusual. Methods A 49-year-old woman had acute low back pain radiation into the left buttock and the lateral aspect of the left leg and left foot. Magnetic resonance imaging study showed a bulging disc and posterior osteophytes at T11-T12. Results Surgical removal of the herniated disc and osteophytes rapidly relieved her symptoms and neurologic deficits. A follow-up neurologic examination 3 years later showed normal motor and sensory functions, although low back soreness was noted occasionally. Conclusion A case of thoracic disc herniation mimicking an acute lumbosacral radiculopathy is presented. Compression of the lumbosacral spinal nerve roots at the lower thoracic level after exit from the lumbar enlargement may be the mechanism for this unusual presentation.

Study design A longitudinal follow-up of Modic changes on magnetic resonance imaging (MRI). Objectives To assess the prevalence and natural course Modic changes over a 3-year follow-up period. Summary of background data Modic changes are bone marrow and endplate lesions visible on MRI. To the authors' knowledge, no follow-up studies on their natural course have been published. Methods The study population consisted of 60 unoperated sciatica patients 23 to 76 years of age. Baseline and 3-year lumbar MR images from L1-L2 through L5-S1 were analyzed independently by 2 radiologists and a consensus reading was performed. Results At baseline, the prevalence of Modic changes was 23%. Seven discs had mixed Type I/II, and 63 Type II change. Changes typically occurred at L4-L5 and L5-S1, and associated positively with age (P = 0.009). Ten of 70 discs (14%) with Modic changes at baseline displayed another type at 3 years. Furthermore, the nonconverted changes increased significantly in size. The incidence of new Modic changes during the follow-up was 6% (13 of 230). Conclusions Modic changes are common MRI findings in patients with degenerative lumbar disc disease. We found evidence that Modic Type II changes may be less stable than previously assumed.

Study design A review of the published literature regarding lumbar arthroplasty. Objective To describe the current state of lumbar total disc replacement and, in particular, the recent clinical results of the Charite and ProDisc trials. Summary of background data Lumbar fusion remains the surgical procedure of choice for patients with chronic low back pain unresponsive to nonsurgical management. Lumbar fusion is a strictly palliative procedure with suboptimal clinical results obtained by a significant proportion of patients. Adjacent segment disease is thought to limit the long-term clinical results with up to 20% of patients requiring secondary surgical interventions within the decade following a "successful" lumbar fusion. Total disc replacement has been developed as a potential means to improve the long-term outcome of these patients. Methods Literature review of total lumbar disc replacement. Results The surgical decision-making process, a description of current lumbar disc arthroplasty devices, and early clinical results are described. Conclusion In appropriately chosen patients, lumbar disc arthroplasty provided clinical results similar to those obtained with interbody fusion at 2 years. The long-term results with respect to the effect of these devices on adjacent segment degeneration are not known, as the incidence of adjacent segment degeneration is not an endpoint of the current trials.

Study Design. A prospective series of biochemical assays for prostaglandin E 2 content in symptomatic herniated lumbar disc specimens. Objectives. The help clarify the pathogenesis of lumbar radiculopathy. Summary of Background Data. Three recent studies have shown elevated levels of prostaglandin E 2 in intervertebral disc herniations. None of these studies correlated symptoms with prostaglandin E 2 levels. Methods. Twenty-four disrupted disc samples were purified by a standard solid phase extraction method and analyzed for prostaglandin E 2 with an enzyme-linked immunosorbent assay. Clinical and anatomic correlations were sought with analysis of variance and t test. Results. Sequestered discs tended to be associated with a higher prostaglandin E 2 content than extruded discs, which in turn, tended to be associated with higher prostaglandin E 2 content than protruded ones. A positive straight leg raising test appeared to be associated with a higher prostaglandin E 2 content than a negative test. Conclusions. Prostaglandin E 2 appears to mediate some of the inflammatory effects of lumbar disc herniation. An intact anulus may provide some protection against this stimulus.

Context. The societal costs of low back pain and associated disability are immense. However, very little is known about the etiology of low back pain. Lumbar disc disease was discovered in the last century and became the predominant etiology for back pair Today we know that for the majority of low back pain cases, a specific etiology cannot be determined Objective. To analyze the evolution of the "disc paradigm" and to compare our contemporaly understanding to the scientific discussion in the beginning of the last century. Design. Survey of the highest ranked German medical journal from 1900 to 1999. Data Extraction. The indexes of 5185 joumal issues of the Deutsche Medizinische Wochenschrift were teviewed for articles about iow back pain. Data Synthesis. For each article, the etiologies were identified, categorized, and counted per decade. in addition, each important etiology was described. Conclusions. In the beginning of the last century, many heterogeneous etiologies coexisted. In the second half of the century, the theory of disc degeneration took over almost the entire literature about low back pain. Pre-existing theries disappeared but re-entered the discussion in the last decade. Two factors seemed to influence this development: 1) a tendency to prefer organic, visible abnormalities as etiologies: and 2) an inclination to trust technical diagnostic results more than clinical judgment.

Emerging techniques for management of degenerative disc disease include modern fusion interbody cage devices, intradiscal electrothermal therapy, and disc prostheses among others. The management of discogenic low back pain is controversial: its accurate diagnosis is difficult, and treatment is inconsistent. Before wide application, the advantages and disadvantages of each procedure must be considered in lieu of inadequate study design and the lack of sufficient long-term outcome studies.

Study design Review article. Objectives To provide an overview of current techniques for minimally invasive lumbar fusion. Summary of background data Minimally invasive techniques have revolutionized the management of pathologic conditions in various surgical disciplines. Although these same principles have been used in the treatment of lumbar disc disease for many years, minimally invasive lumbar fusion procedures have only recently been developed. The goals of these procedures are to reduce the approach-related morbidity associated with traditional lumbar fusion, yet allow the surgery to be performed in an effective and safe manner. Methods The authors' clinical experience with minimally invasive lumbar fusion was reviewed, and the pertinent literature was surveyed. Results Minimally invasive approaches have been developed for common lumbar procedures such as anterior and posterior interbody fusion, posterolateral onlay fusion, and internal fixation. As with all new surgical techniques, minimally invasive lumbar fusion has a learning curve. As well, there are benefits and disadvantages associated with each technique. However, because these techniques are new and evolving, evidence to support their potential benefits is largely anecdotal. Additionally, there are few long-term studies to document clinical outcomes. Conclusions Preliminary clinical results suggest that minimally invasive lumbar fusion will have a beneficial impact on the care of patients with spinal disorders. Outcome studies with long-term follow-up will be necessary to validate its success and allow minimally invasive lumbar fusion to become more widely accepted.

Study design In this multicenter, prospective, 2-year study, 146 male patients underwent a single-level anterior lumbar interbody fusion with a tapered threaded titanium fusion device. All the patients were advised before surgery of the risk for retrograde ejaculation. After surgery, any case of retrograde ejaculation was recorded as an adverse event, and the patient was observed up for the remainder of the study. Objective To determine the incidence of retrograde ejaculation in male patients treated for single-level degenerative lumbar disc disease at L4-L5 or L5-S1 with a stand-alone anterior interbody fusion using tapered, threaded titanium fusion cages. Summary of background data The incidence of retrograde ejaculation in men after anterior lumbosacral spinal surgery has been reported to range from 0.42% to 5.9%. Various risk factors that increase the chance of retrograde ejaculation have been proposed. Methods In this prospective study, 146 male patients underwent an open surgical exposure of the lumbosacral junction and a single-level interbody fusion at either L4-L5 or L5-S1. Assessment of a patient's clinical outcome was based on written questionnaires at 6 weeks and then 3, 6, 12, and 24 months after surgery. Patients were questioned about adverse events at each of these assessments, and any case of retrograde ejaculation was recorded and followed. Results Retrograde ejaculation developed in 6 of the 146 men after open anterior lumbar interbody fusion surgery. Two cases (1.7%; 2/116) involved patients who underwent a retroperitoneal surgical exposure. Four cases (13.3%; 4/30) involved patients who had a transperitoneal surgical exposure. This difference is statistically significant according to Fisher's exact test (P = 0.017). At 12 months after surgery, 2 patients had resolution of their symptoms: 1 in the retroperitoneal approach group and 1 in the transperitoneal group. At the final 2-year follow-up, no changes in symptoms were reported. One patient in the retroperitoneal approach group (0.86%) and three patients in the transperitoneal group (10%) reported permanent retrograde ejaculation (P = 0.027). Conclusions A transperitoneal approach to the lumbar spine at L4-L5 and L5-S1 has a 10 times greater chance of causing retrograde ejaculation in men than a retroperitoneal approach.

The percutaneous treatment of lumbar disc disease with laser energy has emerged recently as an alternative to open surgical or even mechanical percutaneous methods. Although numerous laser wavelengths have been employed in both the experimental and clinical settings, no consensus exists regarding selection of laser, treatment duration, or energy requirements. Inspection of the disc/water absorption spectrum combined with the limitations of the fiberoptic delivery systems argue for the use of lasers near 2.0 microns, such as the 2.1-microns Ho:YAG. Although recently developed in vitro models have allowed for laser system comparisons, most clinical work has been empiric, uncontrolled, and in very small series.

Study design Twenty volunteers and 20 patients with no prior spine surgery had two standing lateral radiographs taken, on the average, 66 months apart and 2 weeks apart, respectively. Objectives To first determine the reliability of the measurement techniques used, and then the longitudinal variation between radiographs for the sagittal spinopelvic alignments measured in two stable populations, the one manifesting no back symptoms (volunteers) and the other showing no changes in symptoms (patients). Pelvic morphology also was assessed quantitatively, and significant correlations for the measurements were studied. Summary of background data There are no published studies on longitudinal variation for measurements of sagittal spinal alignments in asymptomatic control subjects or untreated patients with stable back problems. It may be helpful to know not only how much variation in alignments can be expected between radiographs of the same individual, but also which measurements and measurement techniques offer the greatest clinical reliability and application. Methods Each patient in this study reported mechanical type low back pain that was constant in location and character as well as clinically consistent with symptomatic degenerative lumbar disc disease. Each patient and volunteer had 36-inch-long lateral radiographs taken of the entire thoracic and lumbar spine, which included the pelvis. After intervening periods of 1 to 4 weeks (patients) and 5 to 6 years (volunteers), a second radiograph was taken for comparison. Two observers made 24 different measurements on the radiographs including determinations for lumbopelvic lordosis, pelvic balance, and pelvic morphology using the pelvic radius technique. Reliabilities, longitudinal variations, and correlations for the measurements were compared. Results The most reliable measurements were for pelvic morphology, pelvic balance, and regional lumbopelvic lordosis by the pelvic radius technique. Pelvic morphology was the most constant measurement between individual radiographs. Pelvic morphology and total lumbosacral lordosis were dependent measurements that were complementary in determining total lumbopelvic lordosis. Lumbopelvic lordosis and pelvic balance also had strong correlation, whereas lumbosacral lordosis and pelvic balance were independent measurements. Conclusions The pelvic radius technique is recommended for evaluating lordosis to the pelvis because this approach provided not only good measurement reliability on standing radiographs for lumbopelvic lordosis, but also determination of pelvic balance over the hips and the option to assess pelvic morphology quantitatively. Lumbopelvic lordosis and pelvic balance were strongly correlative. This finding, along with higher reliability and lower longitudinal variation on repeated radiographs, indicated greater clinical application for these specific measurements.

Study Design. A case-control study using magnetic resonance imaging findings and a polymerase chain reaction assay to investigate the association between aggrecan gene polymorphism and lumbar disc degeneration. Objective. To analyze whether the aggrecan gene polymorphism is related to lumbar disc disease in young women. Summary of Background Data. It has been suggested that a genetic factor or familial predisposition contributes to the development of lumbar disc herniation. However, the precise genetic component related to disc disease remains unclear. Recently, a polymorphism has been identified in the region of the human aggrecan gene. The expressed variable numbers of tandem repeat polymorphism occur in the highly conserved repeat region. Methods. The participants were 64 young women with or without low back problems. Magnetic resonance imaging was used to evaluate the degeneration and herniation of the intervertebral disc. Genomic deoxyribonucleic acid was extracted from all participants. A polymerase chain reaction assay was carried out to detect the alleles of the aggrecan gene. The association of intervertebral disc degeneration and herniation with the distribution of the aggrecan gene alleles was analyzed. Results. Findings showed an overrepresentation of alleles with small numbers of repeats in subjects with multilevel disc degeneration, thus indicating a significant distribution difference. There also was a significant difference between the distribution of alleles and the severity of disc degeneration. No significant association was found between any of the alleles either in number or type of disc herniation. Conclusions. The current study showed that multilevel and severe disc degeneration was present in the participants with shorter variable numbers of tandem repeat length of the aggrecan gene. This suggests that subjects with shorter variable numbers at tandem repeat length of the aggrecan gene have a risk of having multilevel disc degeneration develop at an early age.

STUDY DESIGN A cohort study of 12,000 persons with a follow-up period ranging from birth to the age of 28 years. OBJECTIVES To determine the cumulative incidence of lumbar disc disease leading to hospitalization in a well-defined geographic population, with special emphasis on age of onset and differences between the genders and among disease categories. SUMMARY OF BACKGROUND DATA There are few published reports on low back pain in adolescence, and most of them are cross-sectional in design. METHODS The Finnish National Hospital Discharge Register was used to identify all possible cases of lumbar disc disease. Copies of all hospital records regarding the diagnosis and course of the disease were collected and the hospitalizations were classified into three categories: 1) confirmed herniated nucleus pulposus (HNP), 2) unconfirmed HNP (sciatica symptoms without visible herniation), and 3) other low back diseases. The patients were classified according to the highest category of diagnosis achieved by each. RESULTS Symptomatic low back pain leading to hospitalization first appeared around the age of 15 years, and the incidence rose more sharply from the age of 19, especially in men with other low back diseases. Men were hospitalized more than twice as often as women. CONCLUSIONS Lumbar disc diseases leading to hospitalization begin early.

STUDY DESIGN Sagittal alignments, including lumbar lordosis and spinopelvic balance (measured from C7, S1, and hip axis reference points for the relative positions of the spine and sacropelvis over the hips), were studied on standing 36-in. lateral radiographs of adult volunteers (control subjects) and patients who had specific spinal disorders. OBJECTIVES To determine the most reliable methods for measuring lumbopelvic lordosis and to define significant spinopelvic compensations for sagittal balance. SUMMARY OF BACKGROUND DATA Measurements for standing sagittal balance, obtained using a C7 plumb line, and segmental angulations of the spinal vertebrae, including lordosis to the sacrum, have been reported. Absolute values, even for normative data, have had wide variation and limited clinical usefulness. Correlations of sagittal balance with the reported spinopelvic angulations (spinal vertebral and sacropelvic angulations) have not been well defined. In addition, determinates of balance (spinal and pelvic) have not been studied for reliability, and compensatory mechanisms for maintenance of balance have not been carefully evaluated. Better recognition of the correlations and more reliable methods to measure lordosis and balance and the spinopelvic compensations for its maintenance may be beneficial in treating patients who have spinal disorders. METHODS Measurements on standing 36-in. lateral radiographs were made for sagittal alignments in adult volunteers (n = 50) and in adult patients who had symptomatic degenerative lumbar disc disease (n = 50), low grade L5-S1 isthmic (lytic) spondylolisthesis (n = 30), and idiopathic or degenerative scoliosis (n = 30). All participants exhibited clinical compensation for balance. Data were analyzed for significant correlations within each group to determine compensatory correlations of spinopelvic balance with the other sagittal alignments. Intraobserver and interobserver reliability for the parameters evaluated were calculated. This included two methods for determining lordosis (S1 end-plate and pelvic radius techniques). RESULTS Plumb line measurements for balance from the S1 and hip axis reference points, as defined, were similar in all four groups. However, the groups appeared to adjust for balance by using common and distinctive spinopelvic compensations that resulted in significantly and characteristically different angular alignments among the four groups. Lordosis and balance measurements were closely correlated, and the correlation was characterized by pelvic rotation and translation around the hip axis. The subjects with less lordosis typically stood with the C7 plumb line anterior to and at a longer distance from the sacral reference point. This was primarily because of posterior sacropelvic translation around the hip axis and not because the sagittal plumb line initially moved anteriorly away from the sacrum. This was true in all four groups and gave the appearance that the sacropelvis was less well balanced over the hips in the subjects with less lordosis. Even small differences in lordosis appeared to be associated with considerable adjustments in the other spinopelvic alignments. Therefore, it was important to determine that lordosis was lumbopelvic more reliably measured by the pelvic radius technique. CONCLUSIONS Lower lumbar lordosis, by the pelvic radius technique, and compensatory sacropelvic translation around a hip axis, in addition to measurements from this axis to the C7 plumb line, were the primary determinates and most reliable radiographic assessments for sagittal balance. Understanding the common and characteristically different compensations that occur with balance in these patients who had specific spinal disorders may help to improve their care.

The diagnosis and treatment of painful degenerative disc disease remains one of the most controversial topics in the spine literature. The debate continues as to whether surgical treatment should be attempted, and if so, which surgical approach is optimal. Surgical options include the following general types of spinal fusions: posterolateral (instrumented or noninstrumented), anterior lumbar interbody, posterior lumbar interbody, and transarticular facet joint screws. Dr. Nachemson continues to take his long-standing position that the diagnosis is unreliable and that the outcomes are inadequate to justify the risks and costs. Dr. Zdeblick believes that instrumented posterolateral spinal fusions can offer a high degree of success with an acceptably low rate of complications. Finally, Dr. O'Brien believes that the pain generator is anterior and that the treatment should be anterior discectomy and interbody fusion combined with posterior transarticular facet screw fusion.

STUDY DESIGN Degenerative lumbar disc disease has been implicated as a cause of low back pain. Current treatment options for low back pain involve nonphysiologic fusion of the involved segments and have variable success rates. This is an experimental study of lumbar intervertebral disc transplantation using a canine surgical model. OBJECTIVES This study evaluated the feasibility of lumbar disc transplantation and its effects on disc metabolism and morphology. METHOD Eight mature mongrel dogs underwent disc transfer surgeries, in which the L2-L3 and L4-L5 intervertebral discs, with a small segment of adjacent superior and inferior vertebral body, were removed and transposed. The transplanted disc were stabilized by plates or by a flexible cable wire construct using Songer cables (DANEK, Inc., Memphis, TN). Unrestricted activity was allowed postoperatively. At 4 months, the spines were harvested, and the transplanted discs were evaluated biochemically and histologically. Intervening nontransplanted discs served as viable controls and thrice-frozen discs served as nonviable controls. Cell viability was assessed by measuring proteoglycan synthesis and DNA content. RESULTS Proteoglycan synthesis (35S uptake normalized to DNA content) was maintained in transplanted anulus fibrosus tissue, but was decreased in nucleus pulposus samples (P < 0.05). DNA content was not altered significantly in the transplanted discs. Histologic analysis of the transplanted discs showed revascularization and remodeling of the bone adjacent to the disc and preservation of the lamellar architecture of the anulus fibrosus. The transplanted nucleus pulposus samples had chondrocyte-like cells present, but the staining characteristics of the nucleus material was variable. The contour of the transplanted disc endplates was irregular in all specimens. CONCLUSIONS The structure and function of autograft intervertebral discs were maintained after disc transfer surgery; the transplant discs, however, were not completely normal in either their morphology or their metabolic functioning.

This study was undertaken to document an association of degenerative lumbar disc disease in patients with thoracolumbar Scheuermann's disease. During a 3-month period, 9% of 1419 of the persons referred to our center for magnetic resonance imaging of the lumbar spine demonstrated changes of both thoracolumbar Scheuermann's disease and degenerative disc disease in the lower lumbar spine. The disease was less commonly detected on computed tomography (2% of 1522 patients). The patients were relatively young: 81% were younger than 40 years and 9% were younger than 21 years. We theorize that the thoracolumbar Scheuermann's disease and the associated degenerative disc disease of the lower lumbar spine are manifestations of an intrinsic defect of the discs and/or cartilaginous end plates, which results in inadequate nutrition and structural weakness or a combination of both, and early degeneration.

A retrospective analysis of 200 patients requiring cervical disc surgery was performed to determine the frequency of coexistent lumbar disc or spine abnormalities. The duration of follow-up ranged from 5 to 25 years, averaging 14 years. Sixty percent were women and 40% were men, their ages ranging from 25-73 years. Antecedent motor vehicle injury had occurred in 49 cases and work injury to the spine in 23. Sixty-four percent had no history of prior back injury. It was found that over 31% had undergone lumbar disc surgery, and a high number of patients demonstrated abnormal lumbar radiographs or myelograms, including 78 with bulging discs, 100 with major root defects, 78 with minor root defects, 8 with spinal stenosis, and 7 with spondylolisthesis. Myelograms were normal in 22 cases. The sites of lumbar abnormalities included L4-5 (110), L5-S1 (90), and multilevel (8). There was a higher incidence of lumbar disc abnormalities associated with multilevel cervical spondylosis. There also was a relationship between residual symptoms and myelographic abnormalities. Two studies in the authors' institution suggest an autoimmune basis for the frequent coexistence of cervical and lumbar disc disease, namely the demonstration of antigenic properties in the nucleus pulposus and high serum immunoglobulins.

Inflammation of neural elements is frequently mentioned clinically in association with lumbar radiculopathy. Mechanical embarrassment of neural elements by definable structural abnormalities is inadequate as a sole explanation of nerve injury in this condition. The purpose of this study was to demonstrate whether an enzymatic marker for inflammation (phospholipase A2) could be identified in human disc samples removed at surgery for radiculopathy due to lumbar disc disease. Samples were assayed for phospholipase A2 activity. The level of activity in the disc samples was compared with values obtained from other human tissues using the same assay. Specific activity (percent hydrolysis radiolabelled substrate) ranged from 238 to 1,014.5 nmol/min/mg. Mean activity for the human disc material was 568.7 nmol/min/mg, compared with 0.006 nmol/min/mg for human PMN, and 12.1 nmol/min/mg for inflammatory human synovial effusion. The pH and cation-related activity were identical to those demonstrated for phospholipase A2 inflammatory conditions. Human lumbar disc phospholipase A2 activity is from 20- to 100,000-fold more active than any other phospholipase A2 that has been described. As the enzyme responsible for the liberation of arachidonic acid from cell membranes, phospholipase A2 is the rate-limiting step in the production of prostaglandins and leukotrienes. These data establish biochemical evidence of inflammation at the site of lumbar disc herniations.

Forty-two intradiscal injections were performed in 29 patients having lumbar disc disease, 19 of whom had nonradiating back pain and 20 of whom had back and leg pain. Discograms were abnormal for 27 patients, but myelograms were abnormal for only four. Twenty-two injections (52%) gave relief of pain for a minimum of one month, but only 14 (33%) for at least three months. Of the 29 patients, six (21%) have obtained relief lasting six months to several years and have not required surgery. Twenty injections were performed in 14 patients having cervical disc disease, 11 of whom had neck and arm pain and three of whom had discogenic neck pain. Contrast and anesthesia discograms were abnormal for all patients, but myelograms were abnormal for only four. Thirteen injections (65%) gave relief of pain for a minimum of one month, but only three (15%) for at least three months. Of the 14 patients, three (21%) have obtained relief lasting six months to several years and have not required surgery.

The hospital and professional charges for 40 consecutive patients who underwent chymopapain chemonucleolysis in 1982-83 at the University of Wisconsin for single-level lumbar disc disease were compared with the charges incurred by 40 consecutive patients who underwent lumbar laminectomy for single-level disc disease during the same period. The average cost per patient was $4,163 for chemonucleolysis and $6,124 for laminectomy. Three chemonucleolysis patients reported poor results, and all subsequently underwent reoperation by laminectomy. Four laminectomy patients reported poor results, and two of these subsequently underwent reoperation. The costs of chemonucleolysis and lumbar laminectomy were calculated to reflect reoperation costs, and we found that the average cost per patient was $1,808 less for chemonucleolysis. The implications of this saving for national cost containment of lumbar disc surgery are discussed.

Forty-five patients who had lumbar disc surgery 10 or more years previously, and had required a second operative procedure, have been evaluated. Failures occurred up to 16 years after the first operation, and were most commonly due to pseudoarthrosis in the patients who underwent spinal fusion initially, and to recurrent disc lesions at the same level as previous surgery in the patients who did not have fusion. The clinical and functional results in the second group of patients who required a second procedure were comparable to those of patients who required only a single procedure. In contrast, patients who had undergone spinal fusion who required a second procedure had significantly worse clinical and functional results, both in comparison to the patients who did not undergo fusion as well as to patients who had had fusion as a single procedure. The only predictable, demonstrable source of failure was acquired spondylolysis. Frequently, repair of pseudoarthrosis did not lead to symptomatic relief. These data suggest that spinal fusion, when it fails, has a significantly worse prognosis than simple disc excision in the management of lumbar disc disease.

The sagittal dimensions of the five lumbar vertebral canals tend to be more shallow in patients operated for lumbar radiculopathy than in a group of controls. The more frequent occurrence of radiculopathy in patients with small canals can be explained by the requirement for only a small protrusion of intervertebral disc, or any other structural abnormality, to impinge the nerve. The sagittal diameter can be obtained easily from the lateral roentgenogram and, therefore, requires no invasive or expensive tests. This measurement can be quite helpful in interpreting myelographic defects and in planning and doing operations on patients with radiculopathy.

A randomized clinical trial of 30 patients with refractory lumbar disc disease with evidence of a herniation at a single intervertebral space on the myelogram is presented. Collagenase or a saline placebo was injected into the affected disc. Lack of pain reduction or lack of functional improvement was considered a therapeutic failure. Patients who failed to respond to the placebo could subsequently receive a collagenase injection. Thirty-three percent (33%) of the 15 patients who received a placebo and 80% of the 15 patients who received collagenase were rated successful 8 weeks after injection. The study demonstrates a statistically significant effectiveness of collagenase in the treatment of herniated lumbar disc disease.

A type of bilateral laminotomy with discectomy for segmental lumbar discogenic disease is presented. The procedure includes wide bilateral decompressive laminotomies and radical partial discectomies, partial V-ostectomy of the adjacent spinous processes, partial facetectomies of the inferior and superior articular processes, and foraminotomies as indicated. One hundred patients who underwent this procedure were evaluated by an independent examiner in follow-up an average of six years postoperatively. The patients were evaluated by utilizing a scale which included back and leg pain relief, restriction of physical activities, analgesic use, and return to work. Seventy patients were graded as good, 12 as fair, and 18 as poor. Preoperative factors which were highly significantly correlated with a good postoperative result included occupation other than heavy labor, present employment or less than 12 months of unemployment, unilateral subjective paresthesias, symptoms of spinal claudication, unilateral restriction of straight leg raising, a positive Cram or bowstring test, the severity of the myelographic defect, elevation of spinal fluid protein, and the severity of the disc pathology noted at surgery. Several other preoperative factors were noted to be of somewhat lesser significance and were correlated with a poor surgical outcome, including job-related injury, compensation or litigation, previous unsuccessful surgery, subjective weakness, calf atrophy, and sensory deficit.

To identify characteristics of patient presentation that would help distinguish extraosseous spinal tumors from the more common herniated disc, nine cases of intraspinal tumors were reviewed. These nine patients were identified in a group of 744 patients who presented with symptoms similar to disc herniation but failed to respond to conservative care and underwent spinal surgery. This study indicates that intraspinal tumor should be suspected in patients with the following characteristics: 1) painless neurological deficit; 2) night pain or pain which increases in the supine position; 3) pain disproportionate to that normally expected with lumbar disc disease; 4) no change in symptoms after successful surgery for herniated disc; 5) elevated spinal fluid protein; or 6) a teenager with symptoms of disc herniation. Myelography is an effective radiologic procedure for the diagnosis of spinal tumor but MRI should be equally effective if the procedure includes a scan of the conus as well as cauda equina.

The magnitude of the lumbar disc problem is reviewed and a profile of medical and surgical therapeutic expectations is presented. A study of a 5-year epoch of a neurosurgical practice indicated that 64% of all patients requiring disc surgery had satisfactory results and 12% were frank failures. The younger patients with single level disc rupture had the best results, and 18% of all patients required further surgery for recurrent disc problems. The complication rate was 4%. The bias of compensation invalidates any critique of a therapy mode and creates a tremendous economic impact. The need for improvement in the surgical management of lumbar disc disease is established.

Seventy-nine percent of 312 patients who underwent lumbar disc surgery were evaluated at least 10 years postoperatively (mean equal to 13.7 years). Residual back and nerve root symptoms and functional impairment were equally as common among the 143 patients who underwent fusion as they were among the 64 patients who did not. Thirty percent of the patients whose spines were fused and 37.7% of those patients whose spines were not fused were considered long-term failures because of persistent symptoms or the need for reoperation. Thirty-seven percent of the fusion patients had persistent graft donor site symptoms. Examined patients showed a high percentage of residual neurologic defects. An unexplained positive Trendelenburg sign was present in 14.8% of the fusion patients and in 18.2% of the patients whose spines were not fused. Although retrospective studies often have problems of accuracy, this analysis confirms other observations that midline spinal fusion offers few benefits in the management of lumbar disc disease.

It has been our practice to perform total myelography in all cases of lumbar disc disease including the various syndromes of spinal stenosis, because experience has indicated that myelographic abnormalities in the cervical and thoracic areas could have clinical importance despite the presence of gross changes in the lumbar region. Failure to establish a definite diagnosis by restricted lumbar myelography makes it mandatory to evaluate all levels of the spinal axis. Recently, 3 patients with thoracic spinal cord tumors presented with primary signs and symptoms of lumbar spine disorders. Evidence of spinal cord disease was minimal and could be readily overlooked. Total myelography disclosed varying degrees of lumbar spinal pathology, but also showed evidence of lesions in the thoracic region. One proved to be an intramedullary astrocytoma of the spinal cord, and two were schwannomas. The symptoms of low-back pain and lumbar radiculopathy improved after excision of the schwannomas and following x-ray therapy and chemotherapy in the patient with the intramedullary neoplasm.

Limitation of straight-leg raising (SLR) (Lasegue's sign) is considered an important test in the diagnosis of herniated lumbar disc disease. In a prospective study of 55 patients suffering from unilateral sciatica this sign was evaluated. Two aspects were investigated: 1) the interobserver variation, and 2) the correlation between the result of the test and the surgical finding. There was considerable interobserver variation among three observers concerning the measured angle at which pain was elicited. However, in 2/3 to 3/4 of the cases the variation amounted to 10 degrees or less. There was also some discordance in the classification of the type of pain that was elicited. Fifty-two patients underwent surgery; 45 had a prolapsed disc. SLR was "positive" in 49 cases, 43 of whom harbored a prolapsed disc. Crossed SLR was noted in 20, 19 of whom had a prolapsed disc at surgery. Absence of SLR limitation does not preclude the presence of a herniated lumbar disc.