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Background Back pain attributable to lumbar disc herniation is a substantial cause of reduced workplace productivity. Disc herniation surgery is effective in reducing pain and improving function. However, few studies have examined the effects of surgery on worker productivity. Questions/purposes We wished to determine the effect of disc herniation surgery on workers’ earnings and missed workdays and how accounting for this effect influences the cost-effectiveness of surgery? Methods Regression models were estimated using data from the National Health Interview Survey to assess the effects of lower back pain caused by disc herniation on earnings and missed workdays. The results were incorporated into Markov models to compare societal costs associated with surgical and nonsurgical treatments for privately insured, working patients. Clinical outcomes and utilities were based on results from the Spine Patient Outcomes Research Trial and additional clinical literature. Results We estimate average annual earnings of $47,619 with surgery and $45,694 with nonsurgical treatment. The increased earnings for patients receiving surgery as compared with nonsurgical treatment is equal to $1925 (95% CI, $1121–$2728). After surgery, we also estimate that workers receiving surgery miss, on average, 3 fewer days per year than if workers had received nonsurgical treatment (95% CI, 2.4–3.7 days). However, these fewer missed work days only partially offset the assumed 20 workdays missed to recover from surgery. More fully accounting for the effects of disc herniation surgery on productivity reduced the cost of surgery per quality-adjusted life year (QALY) from $52,416 to $35,146 using a 4-year time horizon and from $27,359 to $4186 using an 8-year time horizon. According to a sensitivity analysis, the 4-year cost per QALY varies between $27,921 and $49,787 depending on model assumptions. Conclusions Increased worker earnings resulting from disc herniation surgery may offset the increased direct medical costs associated with surgery. After accounting for the effects on productivity, disc herniation surgery was found to be a highly cost-effective surgery and may yield net societal savings if the benefits of outpatient and inpatient surgery persist beyond 6 and 12 years, respectively. Level of Evidence Level II, economic and decision analysis. See the Instructions for Authors for a complete description of levels of evidence.

Degenerative disc disease is the leading cause of pain and disability in adults in North America, and spinal fusion is the standard treatment. Despite this, it has been discussed among surgeons that (1) spinal fusion deserves reexamination in terms of its long-term consequences and benefits and (2) modern clinical research and development in disc arthroplasty strongly supports its emergence as an alternative. The ability to relieve pain by maintaining motion may be a critical factor in obtaining not only greater pain relief but in preventing adjacent segment degeneration. Early research in arthroplasty devices was promising but cut short. New knowledge in the functional anatomy and biomechanics of the spine has made possible the development of modern arthroplasty devices (eg, Charite Artificial Disc, ProDisc, Maverick device, FlexiCore device) of different constructions and materials (metal-on-plastic, metal-on-metal) and various ranges of motion/mobility that provide a basis for a classification of spinal mode and an assistance in implant selection. Current research also is confronting the critical obstacles of wear and tear and axial compression. Several devices currently are in clinical trials. A detailed review of their characteristics shows the exciting progress of a new treatment era of total disc replacement in spine-lumbar disc arthroplasty.

UNLABELLED A clinical, plain radiographic, and magnetic resonance imaging retrospective followup study was done on six patients with postoperative septic L4-L5 lumbar spondylodiscitis to identify the characteristic long-term radiographic findings predicting the clinical outcome. The mean followup was 12 years (range, 9-13 years). Three patients had moderate low-back pain and two were handicapped. One patient had slight peroneal weakness. Flexibility of the lumbar spine was restricted to some extent in all patients. Laminectomy for spinal stenosis (L4-L5) had been done in one patient and reoperation because of recurring disc herniation was done in two patients. Partial or total bone marrow depletion and corresponding enhancement of fat signals in relation to adjacent vertebral bodies, narrowing of the intervertebral disc space, and irregularity or cavitations affecting one or both end plates were long-term findings of magnetic resonance imaging. Plain radiographs and magnetic resonance imaging scans revealed a complete bony fusion in one patient and partial fusion in one patient. In two patients, residual disc protrusion or herniation in relation to the surgically treated disc was evident; three affecting L3-L4 and two affecting L5-S1 disc levels. Septic postoperative lumbar discitis severely hampers clinical recovery after disc operations and results in long-term changes as seen on magnetic resonance imaging scans. LEVEL OF EVIDENCE Therapeutic study, Level IV (case series--no, or historical control group). See the Guidelines for Authors for a complete description of levels of evidence.

Repair of degenerated intervertebral discs by engineered tissue is a clinical challenge in spinal surgery. Prerequisites are cultivation of intervertebral disc cells and determination of their biologic properties. The influence of disc damage in different spinal disorders on the outcome of disc cell cultures has not been discussed previously. This study showed the feasibility of cultivation of cells from damaged human intervertebral discs and the dependence of cellular culture properties on the underlying disc disorder. Human intervertebral disc cells were isolated from disc tissue obtained during surgical procedures for scoliosis, osteochondrosis, and disc herniation. After proliferation in monolayer culture, cells were embedded in a mixed matrix composed of fibrin and hyaluronic acid. Deoxyribonucleic acid content, hydroxyproline content, and proteoglycan synthesis were determined on Days 7, 14, and 21. In a three-dimensional environment only cells obtained from scoliotic and osteochondrotic discs showed significant deoxyribonucleic acid and proteoglycan synthesis. However, hydroxyproline content increased only in cells from scoliotic discs. The results of this study show that the formation of extracellular matrix components under three-dimensional culture conditions is dependent on the nature of intervertebral disc damage of the tissue processed.

This study investigated the differences in the clinical features of lateral recess syndrome attributable to the bony entrapment of the spinal nerve root under the superior articular facet, and lateral recess syndrome and associated lumbar disc herniation. Ninety patients with pure bony entrapment (47 men, 43 women) ranging in age from 19 to 83 years (mean age, 63 years) and 59 patients with lumbar disc herniation in the lateral recess (43 men, 16 women) 19 to 85 years of age (mean age, 49 years) were included in this study. All patients had L5 root radiculopathies and were treated surgically. Although the early symptoms of patients with lateral recess syndrome often were in the lower extremities, many of the patients with associated lumbar disc herniation had a transition initially experiencing low back pain and subsequently having lower extremity symptoms. Flexion and extension of the lumbar spine exacerbated symptoms, particularly in patients with lumbar disc herniation. The results of the current study show that the clinical presentation of lateral recess syndrome differs depending on the cause of the compression in the lateral recess.

Reaching the L5-S1 disc space through a posterolateral percutaneous approach can be challenging and, at times, disappointing when the iliac crest is too high and the angle between the posterior rim of the iliac bone and the lumbar vertebral column is too acute. The authors are introducing a technique through which the two necessary caudal and axial angles of approach are measured and used for precise passage of the initial trocar into the L5-S1 disc space. Specific bony landmarks and their topographic reflection on the lumbar skin are used in finding the caudal angle and calculating the axial angle. The technique has been used in 43 patients with persistently symptomatic L5-S1 disc protrusions, 27 of whom had high iliac rims. Access to the disc space was achieved in a timely manner in 41 patients who subsequently had percutaneous discectomy. The two unsuccessful procedures were because of the blockage of the access tunnel by an extremely swollen nerve root in one patient and a very large transverse process in the other patient. There were no other complications. Because of its accuracy, although the technique can be used routinely for all the posterolateral percutaneous approaches to the L5-S1 disc space, it specifically is useful for patients with high iliac crests.

Traditionally, lumbar discectomy involves removal of the free disc fragment followed by aggressive or conservative excision of the intervertebral disc. In selected patients, however, it is possible to remove only the free fragment or sequester without clearing the intervertebral disc space. However, there is some controversy about whether that approach is sufficient to prevent recurrent symptoms and to provide adequate pain relief.This systematic review was designed to pose two questions: (1) Does performing a sequestrectomy only without conventional microdiscectomy lead to an increased reherniation rate; and (2) is there a difference in the patient-reported levels of radicular pain?Systematic MEDLINE and EMBASE searches were carried out to identify all articles published in peer-reviewed journals reporting the outcomes of interest for conventional microdiscectomy versus sequestrectomy for lumbar disc herniation from L2 to the sacrum (Level III evidence and above); hand-searching of bibliographies was also performed. A minimum of Level II evidence was required with a followup rate of greater than 75%. Followup in all studies was from 18 to 86 months. Seven studies met the inclusion criteria for this review. The studies were analyzed for operating time, hospital stay, pre- and postoperative visual analog scale, and reherniation rate.Patients in both the microdiscectomy and sequestrectomy groups showed comparable improvement of visual analog scale (VAS) score for leg pain. VAS score improvement ranged from 5.6 to 6.5 points in the microdiscectomy groups and 5.5 to 6.6 in the sequestrectomy group. The reherniation rate in the microdiscectomy group ranged from 2.3% to 11.8% and in the sequestrectomy groups from 2% to 12.5%.This review of the available literature suggests that, compared with conventional microdiscectomy, microsurgical lumbar sequestrectomy can achieve comparable reherniation rates and reduction in radicular pain when a small breach in the posterior fibrous ring is found intraoperatively.

Intervertebral disc degeneration is a common condition with few inexpensive and effective modes of treatment, but current investigations seek to clarify the underlying process and offer new treatment options. It will be important for physicians to understand the molecular basis for the pathology and how it translates to developing clinical treatments for disc degeneration. In this review, we sought to summarize for clinicians what is known about the molecular processes that causes disc degeneration. A healthy disc requires maintenance of a homeostatic environment, and when disrupted, a catabolic cascade of events occurs on a molecular level resulting in upregulation of proinflammatory cytokines, increased degradative enzymes, and a loss of matrix proteins. This promotes degenerative changes and occasional neurovascular ingrowth potentially contributing to the development of pain. Research demonstrates the molecular changes underlying the harmful effects of aging, smoking, and obesity seen clinically while demonstrating the variable influence of exercise. Finally, oral medications, supplements, biologic treatments, gene therapy, and stem cells hold great promise but require cautious application until their safety profiles are better outlined. Intervertebral disc degeneration occurs where there is a loss of homeostatic balance with a predominantly catabolic metabolic profile. A basic understanding of the molecular changes occurring in the degenerating disc is important for practicing clinicians because it may help them to inform patients to alter lifestyle choices, identify beneficial or harmful supplements, or offer new biologic, genetic, or stem cell therapies.

Although lumbar discectomy for treatment of lumbar disc herniation in the general population generally improves patients' pain, function, and validated outcomes scores, results of treatment in elite athletes may differ because of the unique performance demands required of competitive athletes.We performed a systematic review to answer the following questions: (1) What proportion of athletes return to play after lumbar discectomy, and what is the effect of sport? (2) What is the expected recovery time after lumbar discectomy in elite athletes? (3) What is the expected career length and performance of elite athletes after lumbar discectomy?We performed a systematic literature review of articles of lumbar discectomy in the elite athlete population through the MEDLINE and EMBASE databases from 1947 to 2013. Elite athletes were defined as professional, Olympic, or National Collegiate Athletic Association Division I collegiate level. A hand search of the references of all key articles was performed to ensure inclusion of all relevant studies. Information regarding study design, types of athletes, level of sport, recovery time, return to sport, length of career after surgery, and career performance after surgery was extracted. Ten articles met the inclusion and exclusion criteria for this review. These articles consisted of levels III and IV data and were graded based on the Methodological Index for Non-Randomized Studies (MINORS) scale.Overall, the studies included in this review found that 75% to 100% of athletes were able to return to elite competition after operative treatment. In general, a higher proportion of baseball players returned to elite competition compared with other athletes. The reported recovery period after lumbar discectomy ranged from 2.8 to 8.7 months. The average career length after lumbar discectomy ranged from 2.6 to 4.8 years. Elite athletes reached an average of 64.4% to 103.6% of baseline preoperative statistics after lumbar discectomy with variable performance based on sport.A high proportion of elite athletes undergoing lumbar discectomy return to play with variable performance scores on return. Future prospective studies are needed to compare the recovery time, career longevity, and performance for athletes undergoing lumbar discectomy versus nonoperative treatment for lumbar disc herniation.

In ancient times, a supernatural understanding of the syndrome of lumbar radiculopathy often involved demonic forces vexing the individual with often crippling pain. The ancient Greeks and Egyptians began to take a more naturalistic view and, critically, suspected a relationship between lumbar spinal pathology and leg symptoms. Relatively little then changed for those with sciatica until the classic works by Cotugno and Kocher arrived in the late 18th century. Early lumbar canal explorations were performed in the late 1800s and early 1900s by MacEwen, Horsley, Krause, Taylor, Dandy, and Cushing, among others. In these cases, when compressive pathologies were found and removed, the lesions typically were (mis-)identified as enchondromas or osteochondritis dissecans. To better understand the history, learn more about the first treatments of lumbar disc herniation, and evaluate the impact of the early influences on modern spine practice, searches of PubMed and Embase were performed using the search terms discectomy, medical history, lumbar spine surgery, herniated disc, herniated nucleus pulposus, sciatica, and lumbar radiculopathy. Additional sources were identified from the reference lists of the reviewed papers. Many older and ancient sources including De Ischiade Nervosa are available in English translations and were used. When full texts were not available, English abstracts were used. The first true, intentional discectomy surgery was performed by Mixter and Barr in 1932. Early on, a transdural approach was favored. In 1938, Love described the intralaminar, extradural approach. His technique, although modified with improved lighting, magnification, and retractors, remains a staple approach to disc herniations today. Other modalities such as chymopapain have been investigated. Some remain a part of the therapeutic armamentarium, whereas others have disappeared. By the 1970s, CT scanning after myelography markedly improved the clinical evaluation of patients with lumbar disc herniation. In this era, use of discectomy surgery increased rapidly. Even patients with very early symptoms were offered surgery. Later work, especially by Weber and Hakelius, showed that many patients with lumbar disc herniation would improve without surgical intervention. In the ensuing decades, the debate over operative indications and timing continued, reaching another pivotal moment with the 2006 publication of the initial results of Spine Patient Outcomes Research Trial.

Background Lumbar disc herniation (LDH) is a common indication for lumbar spine surgery. The proportion of patients having a second surgery within 2 years varies in the literature between 0.5% and 24%, with recurrent herniation being the most common cause. Several studies have not found any relevant outcome differences between patients undergoing surgery for primary LDH and patients undergoing reoperation for a recurrent LDH, but these studies have limitations, including small sample size and retrospective design. Questions/purposes We (1) compared patient-reported outcomes between patients operated on for primary LDH and patients reoperated on for recurrent LDH within 1 year after index surgery and (2) determined risk factors for worse outcomes. Methods We obtained data from the Swedish National Spine Register, Swespine, where patient-reported outcomes are collected using mailed protocols at 1, 2, 5, and 10 years after surgery. Of the 13,562 patients identified who underwent LDH between January 2000 and May 2011, 13,305 (98%) underwent primary surgery for LDH and 257 (2%) underwent reoperation for a recurrent LDH within the first year. Patient-reported outcomes at 1 to 2 years were available for 8497 patients (63%), 8350 of 13,305 (63%) in the primary LDH group and 147 of 257 (57%) in the recurrent LDH group (p = 0.068). We compared leg and back pain (VAS: 0–100), function (Oswestry Disability Index [ODI]: 0–100), quality of life (EQ-5D: −0.59 to 1.0), patient satisfaction, and global assessment of leg pain between groups. We also analyzed rsik factors for worse global assessment and satisfaction. Results Mean (95% CI) differences in improvement between groups favoring patients with primary LDH were VAS leg pain 9 (4–14), ODI 6 (3–9), and EQ-5D 0.09 (0.04–0.15). While statistically significant, these effect sizes may be lower than the minimal clinically important differences often referred to. Percentage of satisfied patients was 79% and 58% in the primary and recurrent LDH groups, respectively (p

Some studies have assessed inflammatory cells such as macrophages, lymphocytes, and neutrophils in herniated lumbar disc tissues using histologic analysis. However, there is no consensus regarding the relationships between clinical symptoms, including radicular pain and the presence of inflammatory cells. It has been shown that autologous nucleus pulposus relocated on the lumbar nerve root in rats produces time dependent and reversible mechanical hyperalgesia, which is thought to be a pain related behavior in peripheral neuropathic pain models. The purpose of this study was to determine whether leukocytes play a role in the mechanical hyperalgesia induced by the nucleus pulposus and to characterize the role of leukocytes in radicular pain attributable to lumbar disc herniation. Nitrogen mustard was used to induce and evaluate leukocytopenia in rats. Sensitivity to mechanical noxious stimuli was measured quantitatively, and inflammatory cells in granulation tissue around the nerve root were examined histologically. The nucleus pulposus produced neither mechanical hyperalgesia nor abundant inflammatory cells in rats with nitrogen mustard induced leukocytopenia. Neuropathic pain produced by the nucleus pulposus, when placed on the nerve root, may be related to inflammatory cell infiltration induced by relocation of the nucleus pulposus, rather than the nucleus pulposus itself.

In this prospective randomized clinical trial, the results of epidural corticosteroid injections were evaluated in patients with lumbosciatic pain caused by herniated nucleus pulposus. Thirty-six patients with radicular lumbosciatic pain and positive straight leg raising test because of confirmed prolapsed intervertebral lumbar discs were randomized into two groups with (17 patients) and without (19 patients) epidural corticosteroid injection. Members of the treatment groups received three injections of 100 mg methylprednisolone in 10 mL bupivacaine 0.25% each. Additional therapy was standardized and identical in both groups. Followup examinations were performed at 2 weeks, 6 weeks, and 6 months. The examinations included pain level (visual analogue scale), straight leg raising test, and functional status (Hannover Functional Ability Questionnaire). At 2 weeks, patients receiving methylprednisolone injection showed a significant improvement in straight leg raising test results compared with patients in the control group. Results were better in the methylprednisolone group, although not statistically significant for pain relief and mobility. At 6 weeks and 6 months, pain relief, improvement of straight leg raising, and improvement of functional status showed no statistical significance. Epidural corticosteroid injections can be recommended as additional therapy only in the acute phase of the conservative management of lumbosciatic pain.

Recent studies indicate numerous differences between female and male athletes regarding injuries of the upper and lower extremities. Studies have been much less clear concerning a gender differential regarding injuries of the cervical spine. For the purposes of the current review, injuries have been divided into three categories. The first category is cervical strain injury. It has been reported that strain injuries are more prevalent in female athletes than male athletes. The second category is cervical disc injury and cervical disc herniation. It has been reported that the male to female incidence is approximately equal in this category. In the third category, which is referred to as major structural injury, studies to date have almost entirely reported on injuries in males showing a significant male preponderance. With increasing participation of women in contact sports that cause major structural injury, a greater incidence of these injuries may be seen in women.

Although open laminotomy remains an acceptable and, at times, necessary method of treatment for herniated intervertebral discs, spinal stenosis, and various intracanal spinal disorders, arthroscopic disc surgery is emerging as an alternative method of treatment for contained and nonmigrated sequestered herniated discs. Successful performance of arthroscopic disc surgery requires technical skill and a learning curve. Prudent patient selection, adherence to inclusion and exclusion criteria, and avoidance of entry into the spinal canal when possible will reduce the incidence of perineural and intraneural fibrosis and will ensure a satisfactory outcome. Although the incidence of complications has been acceptable, a satisfactory outcome ranging from 75% to 87% has been reported after arthroscopic microdiscectomy. In contrast to nuclear debulking procedures, the objective imaging confirmation of decompression of the nerve root may be shown by immediate postoperative computed tomography or magnetic resonance imaging studies.

Three athletic patients with cauda equina or lumbosacral cord tumor noticed, as an early symptom of the disease, alternating bilateral sciatica synchronized with each stride while jogging. Comparison with athletic patients who developed lumbar disc hernia suggested that this symptom was significant. The authors speculated that the mechanism producing this symptom is the inertial force induced while jogging, which acts on the tumor in its early stage, when it is still quite mobile in the intradural space. The diagnostic role of this symptom in cauda equina and lumbosacral cord tumor should be recognized.

Peripheral nerve tumors may arise in any nerve, large or small. Their presence is readily apparent when they are superficial, but when they are located in a deep nerve, symptoms can mimic+ the nerve root pain of herniated nucleus pulposus. This case of malignant granular cell tumor, probably of Schwann cell origin, involved the sciatic and tibial nerves in the popliteal fossa. Originally the pain was assumed to be produced by a herniated nucleus pulposus. The discovery of the mass thus +was delayed. The mass gave a heterogeneous signal on magnetic resonance imaging studies. A peripheral origin of nerve pain should be considered whenever pain radiates to a limb. A complete physical examination that includes palpation of the nerve to which pain is referred gives the best clue as to the true cause of pain when a peripheral nerve tumor is present.

Surgeries (1155 cases) for cervical myelopathy in a northeastern prefecture (population, 2.26 million) and surrounding areas were reviewed. The annual operation rate per 100,000 residents in the prefecture was 5.7. Most of the patients were in their sixth or seventh decade of life (27% each), but the annual operation rate per 100,000 people of each decade of age was the highest in the eighth decade (16.5 per 100,000 people). At the largest spine center, 41% of 306 patients had a preoperative disease period of more than 1 year, and 65% had severe disabilities. Anterior and posterior compression were about equally chosen. The former, mainly indicated for younger adults and single- or 2-level spinal cord compression, led to better functional improvement. Laminoplasty (93%) was predominant over laminectomy. Forty percent of the patients had developmental stenosis; 48%, dynamic stenosis; 27%, disc herniation; 11%, segmental ossification of the posterior longitudinal ligament; 9%, continuous ossification of the posterior longitudinal ligament; 8%, posterior spur; and 4%, calcification of the ligamentum flavum. Fifty-two percent had more than 1 of these spinal diseases.

Rodent lumbar and caudal (tail) spine segments provide useful in vivo and in vitro models for human disc research. In vivo caudal models allow characterization of the effect of static and dynamic loads on disc mechanics of individual animals with time, but the lumbar models have required sacrifice of the animals for in vitro mechanical testing.We therefore developed a novel displacement controlled in vivo lumbar spine noninvasive induced angular displacement (NIAD) test; data obtained with NIAD were used to compare angular displacement between segmental levels (L4/L5, L5/L6 and L6/S1), interobserver radiograph measurement agreement, and intraobserver radiograph measurement repeatability. Measurements from NIAD were compared with angular displacement, bending stiffness, and moment to failure measured by an in vitro test.Anesthetized Lewis rats were xrayed in a 90° angled fixture, and NIAD was measured at lumbar levels L4 to S1 by two independent and blinded observers. After euthanasia, in vitro angular displacement (IVAD), stiffness, and failure moment were measured for the combined L4-L6 segment in four-point bending.NIAD was greater at L4/L5 and L5/L6 than at L6/S1. Combined coronal NIAD for L4-L6 was 42.8° ± 5.3° and for IVAD was 61.5° ± 3.8°. Reliability assessed by intraclass correlation coefficient (ICC) was 0.905 and 0.937 for intraobserver radiograph measurements, and interobserver ICCs ranged from 0.387 to 0.653 for individual levels. The interobserver ICC was 0.911 for combined data from all levels. Reliability for test-retest NIAD measurements had an ICC of 0.932. In vitro failure moment correlated with NIAD left bending.The NIAD method yielded reproducible and reliable rat lumbar spine angular displacement measurements without required euthanasia, and allows repetitive monitoring of animals with time. For lumbar spine research studies performed during a course of time, the NIAD method may reduce animal numbers required by providing serial angular displacement measurements without euthanasia.Improved methods to assess comparative models for disease or aging may permit enhanced clinical treatments and improved patient care.

Lumbar disc herniation is among the most common causes of lower-back pain and sciatica. The cause(s) of lumbar disc herniation and the relation of lumbar disc herniation to back pain and sciatica have not been fully elucidated, but most likely comprise a complex combination of mechanical and biologic processes. Furthermore, the natural history of lumbar disc herniation seems generally to be favorable, leaving the optimum treatment for lumbar disc herniation a debate in the literature. Various nonoperative and operative treatment strategies have been tried with varying degrees of success. Treatment often involves patient education, physical therapy, alternative medicine options, and pharmaco-therapy. If these fail, surgical intervention is usually recommended. A literature search was conducted to evaluate the currently known effectiveness of traditional and novel non-operative and surgical techniques for the treatment lumbar disc herniation and to determine if there are substantive new advantages in these newer contemporary treatments or combinations thereof. A structured approach to treatment of a patient who may have a symptomatic lumbar disc herniation is presented, based on analysis of the current literature. No one method of nonoperative or operative treatment would seem definitively to be superior to another. Appropriate multidisciplinary treatment including behavioral analysis and support may offer the hope of improved outcomes for patients with lumbar disc herniation.Level V (expert opinion). See the Guidelines for Authors for a complete description of the levels of evidence.

Titanium mesh cages have been used widely for spinal reconstruction since 1986 when they first were introduced. Despite their popularity, relatively few studies have been published on their use in the cervical spine. These cages can be used as structural devices containing autologous local bone or iliac crest bone graft, obviating the need to harvest large structural bone grafts. The main disadvantages of their use are the increased costs and the difficulty of assessing fusion status. The authors review surgical techniques that can be used using titanium mesh cages in cervical spine applications and discuss some of their advantages and disadvantages.

Beginning in January 1994, a prospective, clinical study was done comparing the effectiveness of complete anterior (Group 1) versus partial reamed channel discectomies (Group 2) in 100 consecutive patients who had anterior BAK instrumentation and fusion using autogenous iliac crest bone graft. At 2 or more years of followup, all patients in Group 1 who had complete operative disc removal achieved solid arthrodesis. There were no revision surgeries. However, in Group 2, there were seven patients who had a pseudarthrosis and an additional patient with early postoperative cage displacement, which resulted in eight patients in Group 2 requiring revision surgery. The differences in operative preparation of the disc space for BAK instrumentation surgery resulting in complications proved to be significant. The use of interbody titanium cages dramatically increases the biomechanical efficacy of anterior fusions. Original proponents of cages advocated removing a cylindrical channel of disc material using a drill. A prospective review of 100 patients who had complete versus partial discectomy revealed 14% of patients in Group 2 eventually had a pseudarthrosis develop.

Degenerative spinal stenosis of the lumbar spine is caused by many factors, some of which include: disc herniation, ligamentum flavum and facet hypertrophy, spondylolisthesis, and compression fracture. Most often the stenosis is caused by a combination of these factors. The imaging modalities in routine use to evaluate these conditions are computed tomography, magnetic resonance imaging and computed tomography-myelogram. They each have their advantages and disadvantages although any one of these modalities can adequately diagnose lumbar stenosis. The overall accuracy rate of computed tomography, magnetic resonance imaging, and computed tomography-myelogram has been reported to be similar and even complimentary. It is recommended that the least invasive modality be performed first. Magnetic resonance imaging should be the first choice because it does not require ionizing radiation or contrast injection. The aim of the current study is to present the common causes of lumbar stenosis. Where appropriate, each case is shown with images from each modality so that their similarities and differences can be highlighted.

A review was made of 85 patients who received a second injection of chymopapain because of a recurrent disc herniation between 1980 and 1996. All patients were pretreated for 3 days with H1 and H2 receptor blockers. Immediate sensitivity reactions were not seen. Four Type 1 and one Type 2 reactions were seen after the the second injection. No other complications were seen. In this group of 85 patients, 66 patients received a second injection at the same level as primary treatment after a period of 57.1 months (range, 2-143 months). Two patients were lost to followup. Four patients had surgery, three with good results. Good results and no complications were seen in three patients who had a third chemonucleolysis because of another recurrence after 15, 40, and 56 months, respectively. The remaining 57 patients were interviewed after 64 months (range, 3-143 months). Using the Prolo scale, 51 patients were rated as having excellent or good results, and six patients were rated as having fair or poor results.

In a prospective 2-year followup study of 160 consecutive patients undergoing primary surgery for suspected lumbar disc herniation, the authors studied the diagnostic and prognostic factors by using stepwise logistic regression analysis. When the different factors were entered in the same order as presented clinically, history and pain analysis contained most of the predictive information available. When all factors were entered simultaneously in the computations, the following factors (in order of relative importance) predicted relief of sciatica after 2 years: rupture of the anulus (as opposed to bulging disc or negative exploration), no preoperative comorbidity, and male gender. The following factors predicted return to work at 2 years: no preoperative comorbidity, duration of sciatica less than 7 months, education or vocational training in addition to compulsory school, age younger than 41 years, male gender, and no previous nonspinal surgery. Return to work does not seem to be a valid result parameter in lumbar disc surgery. The most important physical signs were root tension tests and lumbar range of motion, whereas neurologic signs were of secondary importance. Many people have asymptomatic herniations, and today supersensitive diagnostic imaging is widely available. Thus, the importance of clinical evaluation has increased, and most of the relevant information can be obtained by listening to the patient. A simple anamnesis apparently is a good alternative to psychologic tests in surgical triage.

Monosegmental cervical spondylosis with radiculopathy requiring operative intervention responds well to anterior disc excision and fusion with autograft. However, there is a 20% to 25% morbidity from the donor site. Several new surgical techniques using biomechanical spacers or internal fixation have been developed that can be used with local bone or allograft, thus eliminating donor site morbidity. Surgical outcomes are comparable with those of traditional anterior cervical discectomy and fusion.

The investigators describe their multifaceted approach to the study of the relationship between whole body vibration and low back pain. The epidemiologic study was a two center study of drivers and sedentary workers in the United States and Sweden. The vibration exposure was measured in the vehicles. It was found that the career vibration exposure was related to low back, neck, and shoulder pain. However, disability was related to job satisfaction. In vivo experiments, using percutaneous pin mounted accelerometers have shown that the natural frequency is at 4.5 Hz. The frequency response is affected by posture, seating, and seat back inclination. The response appears to be determined largely by the rocking of the pelvis. Electromyographic studies have shown that muscle fatigue occurs under whole body vibration. After whole body vibration exposure the muscle response to a sudden load has greater latency. Vehicle driving may be a reason for low back pain or herniated nucleus pulposus. Prolonged seating exposure, coupled with the whole body vibration, should be reduced for those recovering from these problems. Vibration attenuating seats and correct ergonomic layout of the cabs may reduce the risks of recurrence.

Magnetic resonance imaging in the patient who has had surgery is discussed. The most common indication for postoperative imaging is in the distinction between postoperative fibrosis and recurrent disc herniation. Magnetic resonance imaging is invaluable in the assessment of potential causes of failed back surgery syndrome such as postoperative infection, arachnoiditis and adjacent segment degeneration. Magnetic resonance imaging assumes a less important role in postoperative patients with metal hardware owing to image degradation secondary to metal artifact. Magnetic resonance imaging has a complementary role with computed tomography evaluation of spinal trauma. It excels at the noninvasive evaluation of spinal deformities and neoplasms.

A prospective outcome study to determine the efficacy and complications associated with posterolateral arthroscopic discectomy was initiated in April 1988. One hundred seventy-five patients with symptoms consistent with a lumbar disc herniation and correlative imaging studies were treated operatively, and 169 were available for followup evaluation. Fifty-nine patients with a central herniation or a nonmigrated sequestered fragment were treated using bilateral biportal posterolateral access, whereas 116 patients with radiographic evidence of a paramedial, foraminal, or extra-foraminal herniation were treated using the unilateral uniportal approach. The minimum duration of nonoperative management ranged from 3.5 to 28 months (average, 16 months), and all patients had a minimum of 24 months of postoperative followup. Outcome analysis indicated that 149 procedures were successful, whereas 20 (11.8%) procedures were failures because of persistent radicular symptoms that, in some cases, required open laminotomy. Complications associated with the procedures included one disc space infection, one transient peroneal neuropraxia, and four index extremity skin hypersensitivity. All of these complications resolved without sequelae, and there were no neurovascular complications directly related to the surgical approach.

Inappropriate patient selection for the surgical treatment of lumbar disc herniation remains a major cause of failed laminectomy syndrome. Further experience with the use of a revised objective rating system for patient selection for lumbar laminectomy and discectomy for the treatment for disc herniation is presented. Based on the severity of findings within each of 4 categories (neurologic signs, root tension signs, imaging findings, and psychosocial environment), numeric scores are derived. A maximum of 25 points is available in each category, for a total of 100 points. Scores were determined prospectively in 275 patients who were treated by laminectomy for lumbar disc herniation. Followup averaged 4 years (range, 1 to 12.8 years). Overall, there were 226 (82%) good results, 26 (10%) fair results, and 23 (8%) poor results. Among the 89 patients with compensation/litigation issues, 52 (58%) had good outcomes ; 16 (18%), fair outcomes ; and 21 (24%), poor outcomes. Of the 186 patients without compensation or litigation issues, 174 (94%) had good results; 10 (5%), fair results ; and 2 (1%), poor results. The objective rating score was highly predictive of patient outcome at followup.

The effects of chondroitinase ABC on surgically induced degenerative rabbit intervertebral discs were determined during a 12-week period by magnetic resonance imaging, radiography, and histologic examination. Rabbit intervertebral discs were surgically extruded, inducing disc degeneration 12 weeks before injection of chondroitinase ABC. Magnetic resonance imaging showed a hypointense area in the center of the surgically induced disc degeneration. After injection of chondroitinase ABC, the hypointense area became more intense, but reversed somewhat by the end of the 12-week period. Additional evidence of the effects of chondroitinase ABC on a surgically induced degenerative disc model was shown by radiographic evidence of shrinkage of the disc after injection. Histologic examination revealed a fibrous degenerative disc induced by surgical extrusion. However, the staining properties of the matrix of the nucleus pulposus was similar to that of normal discs before chondroitinase ABC injection, but diminished after the injection, with slight recovery at 12 weeks. The results suggest that chondroitinase ABC induces chemonucleolysis in the degenerated disc. Also, chondroitinase ABC does not destroy the degenerative disc matrix ability to regenerate after 12 weeks.

A prospective clinical trial was conducted involving patients with prolapsed lumbar intervertebral disk proven myelographically, who had anterior diskectomy and disk replacement with a titanium-mesh block implant. A pilot study was done in 1971 on six patients. In this trial, 28 patients were operated on with informed consent. Twenty-three had a minimum of five years' follow-up study. There were 14 men and boys, and nine women and girls. The average follow-up period was eight years and four months (range, five to 12 years three months). The average age at operation was 36 years four months (range, 13-66 years). Symptomatic improvement were divided into three groups. Sixteen patients were in Group 1, three in Group 2, and three in Group 3. Flexion-extension radiographs showed 14 patients with no movement between the vertebral bodies adjacent to the operated disk, five with minimal movement, and four with definite movement. At the implant-bone interface, no radiolucent zone was seen in 18 patients, and a definite radiolucent zone was seen in five. Twenty implants were intact, three implants had developed a crack, and three were deformed. There were no complications. The titanium-mesh block implant is an effective substitute for autogenous bone grafting in interbody fusion.

Symptomatic herniated thoracic disks are rare, for their incidence is calculated at about one in 1,000,000 persons per year. Although these are usually associated with degenerative disease, there are a number of other conditions in which thoracic disk herniation is now recognized as being an uncommon but important feature. Increased use of noninvasive scanning techniques, together with greater clinical awareness, is likely to disclose more cases of herniated disks. Surgical treatment of these herniated disks has undergone extensive modification during the past 50 years. Microsurgical approaches applied to the spine are major contributors to reduced neurologic morbidity. The authors prefer to use the transthoracic approach for surgery. High, low, and far lateral approaches are also discussed, however, as are other surgical approaches used in the mid to low region. Treatment of this difficult diagnostic and management problem is ideally managed by a team of medical professionals which includes highly specialized surgeons.

External transpedicular fixation was applied to the lower lumbar spine in a prospective study on 42 patients with chronic low back pain combined with suspected instability of the lumbar segments; the diagnosis was failed disk surgery, spondylolisthesis, and degenerative disk disease. The aim was to realign the involved segments, to restore disk height, and to record changes in pain and performance during the external fixation test. Pain was recorded on a visual analog scale, and performance was assessed using the Oswestry disability score. As independent observer assessed the test and treatment results. Twenty-nine patients experienced relief of pain and performed better in the fixator; they were subjected to anterior interbody fusion, the external frame being kept as a stabilizing device for an additional four months. Twenty-two patients have had follow-up evaluations for two years. One and two years after successful lumbar fusion, significantly (p0.02) better pain and performance scores were recorded; the results of lumbar fusion corresponded to the preoperative fixation test. A temporary external fixation test may be a useful procedure in patients considered for subsequent spondylodesis.

Significant changes in disk biochemistry were evident in the nuclei pulposi of 25 symptomatic disks that demonstrated abnormal diskography. Compared with the results from ten normal disk from young subjects (mean age, ten years) and from ten asymptomatic disks from adult patients (mean age, 33 years), the symptomatic disks demonstrated significantly greater collagen content than the young and asymptomatic adult subjects, respectively. Significantly fewer total glycosaminoglycans (GAGs) and significantly less water content were also evident for the diseased disks. The mean pH of the nucleus pulposus from 23 patients was also significantly reduced for the symptomatic disks as compared with the mean pH measured for four asymptomatic adult subjects. Although significantly fewer total GAGs were observed for the symptomatic disks, there were no significant differences in the percent composition of hyaluronic acid (HA), chondroitin sulfate (CS), or keratan sulfate (KS) among the normal and symptomatic disks. Significant changes in disk biochemistry are associated with the symptomatic disk, and these changes could contribute to the development of the painful disk syndrome.

A series of 151 patients with cervical spondylotic myelopathy (CSM) were surgically treated through an anterior approach in the period from 1960 to 1987. Particular attention was given to the results of the 52 patients who were operated on more than 12 years ago. Satisfactory short-term results were obtained in all but the few who had incomplete decompression. In these patients, function deteriorated within five years. A disturbing incidence of progression of myelopathy was noted ten years after surgery. Magnetic resonance imaging identified many of the causes (e.g., newly developed intervertebral disk herniation and progression of spondylosis associated with spinal malalignment in both cephalad and caudal directions). Other adverse changes were hypertrophy of the yellow ligament and ossification of the posterior longitudinal ligament. The new and improved techniques consist of decompression to a width of 16 mm or more with intraoperative ultrasonography in addition to extirpation of the posterior longitudinal ligament. This new measure may reduce the incidence of late neurologic deterioration.

Thirteen patients with foraminal or extraforaminal lumbar disk herniation were treated during a 32-month period. Myelography and magnetic resonance imaging proved to be ineffective in identifying the lesion in most patients. High-resolution computed tomography demonstrated the lesions in all patients, and the findings were subsequently confirmed at surgery. Surgical treatment consisting of disk fragment removal and nerve root decompression was effective in relieving radicular pain.

This article is a review of the controversial history of chemonucleolysis. The review begins in 1963 and concludes with recent findings that demonstrated that in properly selected patients, chemonucleolysis can be as effective and safe as laminectomy.

Percutaneous diskectomy is a new method for reducing lumbar disk herniation. This procedure is simple, safe, and only semiinvasive since it causes no direct damage to the dura or nerve roots. This technique employs a nucleotome (blunt-tipped, suction-cutting probe) with a rotating electric shaver (3 mm in diameter) that was specially developed for this procedure. It was applied to 117 patients with lumbar disk herniation whose sciatica had not been relieved by conservative treatments. The results of the technique were considered effective in 94 patients (80.3%). The improvements were even more marked in patients with protrusion or prolapse type herniation. Reviewed with postoperative examinations using magnetic resonance imaging (MRI), excision of the herniated disk, resulting in decompression of the nerve root, may be correlated with the relief of symptoms.

Thirteen patients with spondylolisthesis (six isthmic type and seven degenerative type) and ten patients with intervertebral disk herniation were treated by anterior lumbar interbody fusion. Preoperative and postoperative computed tomography (CT) scans were performed for each patient, and changes in anteroposterior (AP) diameter and lateral diameter of the dural sac, the area of the dural sac, and the amount of disk bulging were measured. The periodic tomogram was done in all patients postoperatively, and one- and two-year fusion rates were calculated. The calculations were compared with the early and late clinical results. The early clinical results after operation were excellent in 26.1%, good in 56.5%, and fair in 17.4%. The late clinical results were similar to early results. The early clinical results correlated with the changes in the spinal canal, such as an increase in AP diameter of the dural sac and a decrease in amount of disk bulging after anterior interbody fusion. There was statistical correlation between the early clinical results and the change in AP diameter of the dural sac. But the late clinical results were influenced by multiple factors including solid bony fusion.

Even the careful and knowledgeable spine surgeon will encounter a variety of neurologic complications during and after routine lumbar laminectomy. These include dural and nerve root injuries; cauda equina syndrome; and formation of scar tissue, extradural and intradural (arachnoiditis). The surgeon must be prepared to identify each of these problems and deal with them effectively at the time of the procedure and in the immediate postoperative and follow-up periods. The physician evaluating the multiply-operated lumbar spine patient must use an organized approach. The origin of the problem in most instances is a faulty decision to perform the original operative procedure. Further surgery on an "exploratory" basis is not warranted in any situation and most likely will lead only to further disability. There should be definite objective findings to substantiate the patient's symptoms. The etiology of each patient's symptoms. must be accurately localized and identified. Medical status and psychosocial situation--as well as orthopedic and neurologic findings--should be evaluated at the time of the initial consultation. Once the spine is identified as the probable source of symptoms, specific features should be sought in the patient's clinical history, physical examination, and roentgenographic studies. The number of previous operations, length of pain-free interval, and predominance of leg versus back pain are the major historic signposts. The presence of a tension sign and the neurologic findings are the focal points of the physical examination. Plain roentgenograms, motion films, water-soluble myelogram, computed axial tomography, and magnetic resonance imaging with contrast have specific roles in the workup.(ABSTRACT TRUNCATED AT 250 WORDS)

Flexion-distraction injuries are often treated by open reduction and fusion using compression instrumentation. Three cases that were complicated by disk herniation at the injured level, with an acquired neurologic deficit, are reported. Middle-column failure through the annulus fibrosis (Gertzbein and Court-Brown Type A) appeared to be a common feature. This may be a permissive condition for this complication as compression is applied across the torn annulus. Preoperative magnetic resonance imaging and postreduction myelography may identify such herniations. Acquired neurologic deficits after reduction and instrumentation demand emergent evaluation and treatment.

A series of 12 patients with failed chemonucleolysis were analyzed to determine the various causes of such failures. The ultrastructural findings observed in laminectomy specimens did not account for the failure in the enzyme treatment. The findings suggested deficient cellular nutrition secondary to enzymatic histolysis of the nucleus pulposus.

Radiography (plain roentgenography, myelography, computed tomography (CT), computed tomographic myelography) has been used to identify morphologic changes involving the various components of the diskovertebral unit. Added to this armamentarium of imaging techniques is magnetic resonance (MR) imaging, with its superior ability to define anatomy, its improved contrast sensitivity, and its potential to provide unique biochemical and physiologic information. The authors review the current use of MR imaging in defining degenerative changes in the spine including the various patterns of herniation, annular tears, canal stenosis, and the use of gadolinium-diethylenetriamine-pentaacetic acid for previously unoperated and operated patients. Prospective studies have compared surface-coil MR imaging, CT, and myelography in the evaluation of disk herniation and stenosis and found an 82.6% accuracy between MR imaging and surgical findings for the type and location of the disease. Recent experience with precontrast and postcontrast MR imaging in the postoperative lumbar spine indicated that it was 96% accurate in differentiating scar from disk in 44 patients at 50 reoperated levels. Three-dimensional imaging is, more and more, becoming an integral part of routine MR imaging. The theoretical and practical advantages of three-dimensional imaging are several and include a theoretical increase in the signal-to-noise ratio over two-dimensional imaging (by the square root of the number of partitions selected), the ability to obtain thin contiguous slices from the volume without the problem of cross-talk found in two-dimensional imaging, more accurate slice thickness than that achieved in two-dimensional imaging, and a reduction in susceptibility artifacts. Different three-dimensional techniques are capable of providing either high or low signal intensity cerebrospinal fluid (CSF), with excellent suppression of CSF pulsation artifacts. Certain sequences provide a high enough signal intensity that a computer algorithm may be used to display the CSF in a rotating three-dimensional manner, similar to a myelogram. This three-dimensional myelographic image has the potential of providing the clinician with a global assessment of the CSF spaces, an advantage previously lacking with other imaging techniques.

Vascular damage and fibrosis are common within the vertebral canal and intervertebral foramen. The grossest examples occur in patients who have previously undergone oil-based myelography or spinal surgery. The mechanisms of fibrosis in the latter instance may be related to persisting cotton debris from sponges used during the operation. This debris may act as a fibrogenic stimulus. However, in cadaveric studies of nonoperated spines, the author and his colleagues have found clear evidence of vascular damage and fibrosis within the spines, and this vascular damage is significantly related to the severity of degenerative disk disease. Degenerative disk disease with osteophytic proliferation and disk protrusion may lead to compression of epidural veins with dilation of noncompressed veins. There is a significant statistical relationship between the extent of the disk degeneration and prolapse and the evidence of venous compression and dilatation. The dilatated veins may contain antemortem thromboses. In turn, there is a significant statistical relationship between the evidence for venous obstruction and perineural fibrosis. Such a relationship also exists between perineural fibrosis and neuronal atrophy. If therefore appears likely that venous obstruction with resultant hypoxia is an important mechanism leading to nerve root damage. In the peripheral blood, significant defects in the fibrinolytic system correlate with the severity of the symptoms. However, it was not possible to correlate these changes with individual clinical or imaging features. These fibrinolytic changes are recognized as markers of vascular damage and may reflect the pathologic processes that the author and his colleagues have demonstrated. It is uncertain whether they play any secondary pathogenic role in the chronicity of these back problems.(ABSTRACT TRUNCATED AT 250 WORDS)

In a continuous series of 770 patients with a herniated disk treated by chemonucleolysis, 16 patients had herniation of the L3-L4 disk (2.1%). There were no complications, and none of these 16 patients had open surgery after the initial treatment. A follow-up study was performed after 39 months (range, six to 80 months) in 15 patients. Three patients were for the most part satisfied and 12 patients were fully satisfied with the result of treatment. Residual pain was minor in most patients. Roentgenographic signs of increased disk degeneration were seen in six patients, and reexpansion of the disk to some degree was noted in four patients. Chemonucleolysis is effective for treatment of the herniated L3-L4 disk.

The interaction of laser radiation with the nucleus pulposus from autopsy specimens of human intervertebral disks was evaluated at different wavelengths (193 nm, 488 nm514 nm, 1064 nm, 1318 nm, 2150 nm, 2940 nm, and 10600 nm). A significant correlation of linear least squares fit of the mass ablated as a function of incident energy was found for all lasers used except the Excimer at 193 nm. The 2940-nm Erbium:YAG laser was most efficient in terms of mass of disk ablated per joule in the limited lower range where this wavelength was observed. At higher energy levels, the CO2 laser in the pulsed mode was most efficient. However, the Nd:YAG 1064-nm and 1318-nm lasers are currently best suited for percutaneous laser disk decompression because of the availability of usable waveguides. Carbonization of tissue with the more penetrating Nd:YAG 1064-nm laser increases the efficiency of tissue ablation and makes it comparable to the Nd:YAG 1318-nm laser.