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PubMed2003

Intraoperative biomechanical assessment of lumbar spinal instability: validation of radiographic parameters indicating anterior column support in lumbar spinal fusion.

STUDY DESIGN: Lumbar spinal instability was evaluated using radiographic parameters and intraoperative biomechanical measurement. OBJECTIVES: To validate a conventional radiographic assessment using an intraoperative biomechanical measurement and to determine the radiographic parameters indicating anterior column support in lumbar spinal fusion. BACKGROUND: Posterior lumbar interbody fusion is gaining acceptance in the treatment of degenerative spondylolisthesis, whereas posterolateral fusion alone may result in good clinical outcomes. A quantitative biomechanical assessment of spinal instability is essential to determine the optimal method of spinal arthrodesis. MATERIALS AND METHODS: Nineteen cases with symptomatic degenerative spondylolisthesis were included in this study. All were candidates for pedicle-screw instrumented lumbar arthrodesis. A total of five L3-L4 segments and seventeen L4-L5 segments were investigated. Radiographic assessment included disc angle, range of motion (ROM), percent of slip, and percent of posterior disc height. Distraction stiffness of the operative segment was measured intraoperatively using a strain-gauged spreader. RESULTS: Disc angle in flexion and ROM were highly correlated to distraction stiffness. Severity of slip, disc space narrowing, and facet tropism did not influence the distraction stiffness. The cases with segmental kyphosis in flexion had significantly lower distraction stiffness than those showing segmental lordosis in flexion. CONCLUSIONS: Disc angle in flexion and ROM were the most prognostic parameters of lumbar distraction instability. Although the option of spinal arthrodesis method should be determined based on both clinical manifestation and imaging studies, the current study demonstrated that providing of anterior column support is biomechanically reasonable for degenerative spondylolisthesis with segmental kyphosis in flexion.

Aged↗
PubMed1997

Maturation of the posterolateral spinal fusion and its effect on load-sharing of spinal instrumentation. An in vivo sheep model.

UNLABELLED: We investigated the temporal relationship among the biomechanical, radiographic, and histological properties of a posterolateral spinal fusion mass to elucidate the changes in load-sharing of the spinal instrumentation and that of the fusion mass throughout the healing process. Destabilization of the posterior spinal column and transpedicular screw fixation at the segments between the third and fourth and the fifth and sixth lumbar vertebrae was performed in twenty-four sheep. A posterolateral spinal arthrodesis with use of autologous corticocancellous bone graft was done randomly at one of the two segments; the other segment (without bone graft) served as the instrumented control. Six animals each were killed at four, eight, twelve, and sixteen weeks postoperatively. Biomechanical testing showed that the posterolateral fusion mass had increased mechanical stiffness after the fourth week. The strain on the hardware, measured with use of rods instrumented with strain-gauges, decreased significantly (p < 0.01) beginning at eight weeks. Radiographically, three independent observations of each of the six animals at each time-period showed that, although all of the fusion masses were considered solid unions at sixteen weeks, bridging of trabecular bone was noted during only ten of eighteen observations at twelve weeks, three of eighteen observations at eight weeks, and none of eighteen observations at four weeks. Computerized tomography and histomorphometric analyses demonstrated that mineralization in the fusion mass increased in a linear fashion even after eight weeks. Histologically, the fusion mass consisted predominantly of woven bone at eight weeks; thereafter, it was gradually trabeculated. CLINICAL RELEVANCE: We found a great discrepancy between biomechanical stability and histological maturation of the posterolateral fusion mass. The biomechanical properties of a stable spinal fusion preceded the radiographic appearance of a solid fusion by at least eight weeks, suggesting that immature woven bone provided substantial stiffness to the fusion mass. The spinal instrumentation was subjected predominantly to bending stress rather than to axial stress, and the load-sharing of the spinal instrumentation decreased concurrently with the development of the spinal fusion.

Animals↗
PubMed1984

Pseudarthrosis resulting in complete paraplegia fifteen years after spinal fusion.

Paraplegia immediately following spinal fusion is a known problem. This case demonstrates the importance of long-term follow-up of fusion patients. Prompt attention must be given to any change in neurological status. A careful check must be made for pseudarthrosis and for secondary compression of the spinal cord as possible causes of neurological compromise.

Adolescent↗
PubMed1998

Intervertebral disc distraction with a laparoscopic anterior spinal fusion system.

The BAK spinal fusion system has been applied to laparoscopic anterior lumbar interbody fusion. The system, consisting of a pair of cylindrical implants with threads, placed symmetrically about the sagittal plane, functions by tensioning the annulus fibrosis. Cylindrical plugs of increasing size are inserted prior to the implant placement. As the procedure may affect spinal posture and disc height, we measured changes due to incremental plug insertion using human cadaveric spine specimens (L5-S1, n = 4). Multi-directional flexibility of the construct was also measured as a function of plug size. The disc height change was found to increase initially and then to level off at 13-mm diameter plugs. In the sagittal plane, the intervertebral posture first shifted towards kyphotic then came back to the initial lordotic posture with plugs of bigger size. However, changes in disc height and spine posture were not statistically significant. Comparing the neutral zone (NZ) flexibility after inserting the plugs to the intact values, neither the flexion/extension nor the axial rotation NZ showed any significant change. In lateral bending, the NZ decreased after the insertion of 13-mm plugs (p < 0.05). Insertion of plugs of increasing size from 9 mm to 12 mm decreased the range of motion (ROM) in all directions (p < 0.05). Insertion of 13-mm and 14-mm plugs decreased the flexion/extension and lateral bending ROM, but not the axial rotation ROM, probably indicating some injury to the annulus fibers.

Adult↗
PubMed1987

Removal of sublaminar wires after spinal fusion.

Eighteen patients who had had spinal fusion using Harrington rods with sublaminar wires underwent removal of the implants because of tenderness over the implants. There were no important complications. At final follow-up, no patient had a change in neurological function as compared with the preoperative assessment, and all reported relief of the preoperative tenderness. We concluded that the removal of rods and sublaminar wires from patients who have had a spinal fusion is clinically safe and effective.

Adolescent↗
PubMedDate not supplied

Epidural pain management for the pediatric spinal fusion patient.

Pain management immediately following a spinal fusion is an important issue for patients and nurses. This article describes the procedure, details nursing considerations for epidural pain management following spinal fusion surgery, and includes data from our institution's 2 years of experience with this type of pain management. With proper nursing education, anesthesia management, and orthopaedic surgeon support, epidural analgesia following spinal fusion surgery is a viable alternative to conventional methods.

Analgesia, Epidural↗
PubMedDate not supplied

Animal models for spinal fusion.

Animal models for spinal fusion are essential for preclinical testing of new fusion methods and adjuncts. They allow for control of individual variables and quantification of outcome measures. Model characteristics are considered. Preclinical experiments to evaluate proof of concept, feasibility, and efficacy are generally studied in an orderly progression from smaller to larger animal models with an evolving cascade of evidence which has become known as the "burden of proof". Methods of fusion analysis include manual palpation, radiographs, computed tomography, histology, biomechanical testing, and molecular analysis. Models which have been developed in specific species are reviewed. This sets the stage for the interpretation of studies evaluating bone graft materials such as allograft, demineralized bone matrices, bone morphogenetic proteins, ceramics, and others with consideration of the variables affecting their success. As evidence accumulates, clinical trials and applications are defined.

Animals↗
PubMedDate not supplied

Cell technologies for spinal fusion.

For a successful spinal fusion to occur, several vital elements are necessary. They consist of the presence of the bone-forming cell (osteoblast) or its precursor, the appropriate biological signals directing bone synthesis, and a biocompatible scaffold on which the process can occur. The most critical of these components is the osteoblast or its precursor, the mesenchymal stem cell (MSC), both of which possess the ability to form bone. As a result, many current techniques attempt to maximize the benefits derived from harvesting the ready source of MSCs from bone marrow, while minimizing the associated complications. These cellular technologies seek to improve on the harvest and concentration of the MSCs or enhance their delivery and action. This review focuses on the terminology, historical underpinnings, and current research rationale and techniques and discusses the possible future of these technologies.

Animals↗
PubMed2005

The effect of nonsteroidal anti-inflammatory agents on spinal fusion.

A large body of information suggests NSAIDS have a negative impact on the healing of bone. Although each clinical healing scenario presents a slightly different level of challenge, the healing of a posterolateral spinal fusion is one of the most difficult challenges in bony healing. Clinically, this results in a relatively high rate of nonunions using traditional fusion techniques. Spinal fusion models have confirmed NSAIDS have a definite inhibitory effect on healing of the fusion. Although data are limited, it appears this effect is most severe when NSAIDS are administered in the early postoperative period. Moreover, the effect may be worse with certain types initial inflammatory, subsequent reparative, and final remodeling phases. Because of the anti-inflammatory activity of NSAIDS, one might assume their effects would be worse when administered in the inflammatory phase. Indeed, the study by Riew et al suggests the inhibitory effects are more significant when NSAIDS are administered earlier following fusion. Other studies conducted with non-spinal models also suggest early administration of NSAIDS results in greater inhibition of bone formation (Goodman et al). Unfortunately, the length of the inflammatory phase in humans is not well known. This leaves the clinician unsure about the safe time to allow resumption of NSAID usage clinically. It appears likely NSAID use following a spinal fusion procedure will increase the rate of pseudarthrosis. The literature suggests that avoidance of NSAIDS in the postoperative period may avoid nonunion. Additionally, we propose that chronic NSAID usage should be addressed in a similar manner to cigarette smoking. While neither are absolute contraindications to elective spinal fusion, patients should be counseled to discontinue the use of NSAIDS in the peri- and postoperative period to maximize their chance for a successful fusion.

Animals↗
PubMed1984

Lumbosacral spinal fusion. A biomechanical study.

The effects of spinal fusion on fused segment and the adjacent, unfused segments play a significant role in the clinical effectiveness of spinal fusion for low-back pain with or without sciatica. Much of the information on this important subject is derived from clinical impressions. The purpose of this biomechanical study is to investigate the altered kinematics and biomechanics of the three different types of spinal fusion (posterior, bilateral-lateral, and anterior) on the adjacent, unfused segment as well as within the fused segment and to investigate their clinical implications. Sixteen fresh human cadaver lumbosacral spines were tested under a simulated physiologic loading condition. The test specimens included three motion segments, L3-4, L4-5, and L5-S1. To study the mechanics of the lumbar spine under combined compression and bending loads, a special apparatus was designed. These loads were applied by an MTS machine through two sets of pulley systems. The loads, as well as displacement data from both actuators, were recorded. A video camera system was utilized to record the kinematics of the spinal motion segment. The unfused specimen was tested first, and the fused specimen then was retested under the identical loading conditions. A total of 16 spine specimens were tested and evaluated--five posterior, four bilateral-lateral, and seven anterior fusions. All types of fusion resulted in increased bending and axial stiffnesses. Overall, anterior fusion provided the largest increase in stiffness, followed by bilateral-lateral fusion and posterior fusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2000

The effect of cigarette smoking and smoking cessation on spinal fusion.

STUDY DESIGN: The effect of cigarette smoking and smoking cessation on spinal fusion was studied in a retrospective review of 357 patients who had undergone instrumented spinal fusion. OBJECTIVE: To document the widely assumed but unreported benefit of cigarette smoking cessation on fusion rate and clinical outcome after spinal fusion surgery. BACKGROUND DATA: Cigarette smoking has been shown to inhibit lumbar spinal fusion and to adversely effect outcome in treatment of lumbar spinal disorders. Prior reports have compared smokers and nonsmokers, as opposed to comparing smokers and quitters. METHODS: This study retrospectively identified 357 patients who underwent a posterior instrumented fusion at either L4-L5 or L4-S1 between 1992 and 1996. Analysis of the medical record and follow-up telephone surveys were conducted. Clinical outcome and fusion status was analyzed in relation to preoperative and postoperative smoking parameters. RESULTS: In this study, the nonunion rate was 14.2% for nonsmokers and 26.5% for patients who continued to smoke after surgery (P < 0.05). Patients who quit smoking after surgery for longer than 6 months had a nonunion rate of 17.1%. The nonunion rate was not significantly affected by either the quantity that a patient smoked before surgery or the duration of preoperative smoking abatement. Return-to-work was achieved in 71% of nonsmokers, 53% of nonquitters, and 75% of patients who quit smoking for more than 6 months after surgery. DISCUSSION: These results validate the hypothetical assumption that postoperative smoking cessation helps to reverse the impact of cigarette smoking on outcome after spinal fusion.

Adult↗
PubMed1986

Aortic laceration after anterior spinal fusion.

Six weeks after anterior spinal fusion and instrumentation for a burst fracture of the second lumbar vertebra, a patient developed a nearly fatal retroperitoneal hemorrhage from a laceration of the aorta produced by the metallic implant. This experience suggests that placement of fusion hardware in close proximity to large arteries should be avoided if possible or, if such placement is necessary, the device should be removed as soon as fusion has taken place.

Adult↗
PubMed1999

Activities and functional assessment 1 year after spinal fusion for paralytic scoliosis.

The results of spinal fusion in patients with paralytic deformities are usually presented as the correction of the deformity. When evaluating the surgical results in such patients, it is advantageous to classify the patients into subgroups because of the varying dysfunction and disabilities. The aim of this study was to evaluate the effect of spinal fusion in patients with paralytic scoliosis in relation to function in terms of Impairments, activities in terms of Disabilities, and dependence in terms of Handicaps 1 year postoperatively, with emphasis on subgroups. A total of 94 patients with paralytic scoliosis and 18 different diagnoses were evaluated 1 year after surgery. The patients were classified according to whether or not they could understand verbal instructions. The patients were also grouped according to the Scoliosis Research Society classification of diagnoses. A set of instruments was used with the variables classified according to WHO's International Classification of Impairments, Disabilities, and Handicaps (ICIDH). This consists of the patient's/relative's motives for surgery, persistent skin discoloration, ambulating or use of wheelchair, use of a brace, sitting balance, weight distribution on a sitting surface, angle of scoliosis, reaching, pain estimation, activities of daily living (ADL) Klein and Bell, care given, time spent resting, and seating supports. The set of instrument also included a follow-up questionnaire comprising 12 different areas, where the patients/relatives assessed the results of surgery. The study showed that spinal fusion in paralytic scoliosis led to showed improvements in the whole group of patients at the Impairment level in the angle of scoliosis, sitting balance, weight distribution, and reduced number of patients with persistent skin discoloration, and at the Handicap level in reduced time for resting during the day, reduced number of seating supports in the wheelchair, and in the use of a brace. Most of the parameters were unchanged. The results in the subgroups were almost the same as in the whole group, although pain and reaching at the Impairment level, and ADL at the Disability level, could not be measured in the patients who were unable to understand verbal instructions. The subjectively assessed results showed that seating posture was ranked positively irrespective of the motive for surgery. The study showed that the patients with paralytic scoliosis maintained or improved their function and level of independence in terms of Impairment and Handicap 1 year postoperatively. The subjective results assessed by the patients/relatives also showed a positive outcome of surgery. Weight distribution on a seating surface was improved, but still uneven, and with respect to better sitting balance and increasing time sitting in a wheelchair, this can involve a risk for pressure sores and needs further investigation. When introducing outcomes including the Disability level, one must take the importance of homogeneity in the groups into consideration.

Activities of Daily Living↗
PubMedDate not supplied

The effects of doxorubicin (adriamycin) on spinal fusion: an experimental model of posterolateral lumbar spinal arthrodesis.

BACKGROUND CONTEXT: Malignant spinal lesions may require surgical excision and segmental stabilization. The decision to perform a concomitant fusion procedure is influenced in part by the need for adjunctive chemotherapy as well as the patient's anticipated survival. Although some evidence exists that suggests that chemotherapy may inhibit bony healing, no information exists regarding the effect of chemotherapy on spinal fusion healing. PURPOSE: To determine the effect of a frequently used chemotherapeutic agent, doxorubicin, on posterolateral spinal fusion rates. STUDY DESIGN/SETTING: Prospective animal model of posterolateral lumbar fusion. OUTCOME MEASURES: Determination of spinal fusion by manual palpation of excised spines. Plain radiographic evaluation of denuded spines to evaluate intertransverse bone formation. METHODS: Thirty-two New Zealand White rabbits underwent posterior intertransverse process fusion at L5-L6 with the use of iliac autograft bone. Rabbits randomly received either intravenous doxorubicin (2.5 mg/kg) by means of the central vein of the ear at the time of surgery (16 animals) or no treatment (16 animals; the control group). The animals were euthanized at 5 weeks, and the lumbar spines were excised. Spine fusion was assessed by manually palpating (by observers blinded to the treatment group) at the level of arthrodesis, and at the adjacent levels proximal and distal. This provided similar information to surgical fusion assessment by palpation in humans. Fusion was defined as the absence of palpable motion. Posteroanterior radiographs of the excised spines were graded in a blinded fashion using a five-point scoring system (0 to 4) devised to describe the amount of bone observed between the L5-L6 transverse processes. Power analysis conducted before initiation of the study indicated that an allocation of 16 animals to each group would permit detection of at least a 20% difference in fusion rates with statistical significance at p=.05. RESULTS: Eleven of the 16 spines (69%) in the control group and 6 of the 16 spines (38%) in the doxorubicin group fused. This difference was statistically significant (=.038). There was no significant correlation (p>.05) between the radiographic grade of bone formation (0 to 4) and fusion as determined by palpation. There were four wound infections in the control group and four in the doxorubicin group. However, solid fusions were palpated in three of these four spines in both the control and treatment groups. CONCLUSIONS: No significant differences in wound complications were noted with doxorubicin administration. A single dose of doxorubicin administered intravenously at the time of surgery appears to play a significant inhibitory role in the process of spinal fusion. If similar effects occur in humans, these data suggest that doxorubicin may be harmful to bone healing in a spine fusion if given during the perioperative period. Further investigation will be necessary to determine the effect of time to aid at determining whether doxorubicin administered several weeks pre- or postoperatively results in improved fusion rate, and whether bone morphogenetic proteins can overcome these inhibitory effects.

Animals↗
PubMed1990

Posterior spinal fusion: allograft versus autograft bone.

The effectiveness of allograft bone for posterior spinal fusion in neuromuscular scoliosis is controversial. Thirty patients with cerebral palsy, treated with posterior spinal fusion, were divided into two groups. Group 1 consisted of 18 patients treated by posterior spinal fusion using autogenous bone graft. Group 2 consisted of 12 patients treated by posterior spinal fusion using freeze-dried allograft bone. The average preoperative curve of 70 degrees in Group 1 was corrected to 35 degrees (50% correction). At 3.2 years average follow-up, the curves averaged 51 degrees (46% loss of correction). The average preoperative curve of 80 degrees in Group 2 was corrected to 39 degrees (51% correction). At 3.5 years average follow-up, the curves averaged 54 degrees (38% loss of correction). Anesthesia time decreased from 344 to 281 minutes (p less than 0.05), and intraoperative blood loss decreased from 2730 to 1740 ml (p less than 0.025) when allograft bone was used as a substitute for autograft bone. Freeze-dried allograft bone is a readily available, safe, and effective substitute for autogenous bone graft in patients with cerebral palsy undergoing posterior spinal fusion.

Adolescent↗
PubMed2002

Use of osteogenic protein-1 in spinal fusion: literature review and preliminary results in a prospective series of high-risk cases.

OBJECT: The safety and effectiveness of osteogenic protein (OP)-1 putty (recombinant human bone morphogenetic protein-7) in promoting fusion in complex spinal cases was studied in nine cases. METHODS: The authors prospectively evaluated nine patients requiring spinal fusion in whom there were medical risk factors that would inhibit osseous fusion. Intraoperatively the OP-1 putty mixed with autologous bone was placed at the fusion site. Outcome measurement instruments were used to provide information on patient demographics, comorbidities, and pain. The Short Form (SF)-36 questionnaire and Oswestry Disability Index (ODI) were administered pre- and postoperatively. All patients underwent routine radiography of the surgery site during follow-up examination. The age of the five women and four men ranged from 21 to 74 years (mean height 1.6 m, mean weight 76.7 kg). Risk factors included mucopolysaccharide syndrome, adrenal insufficiency, rheumatoid arthritis with chronic corticosteroid use, morbid obesity, and heavy smoking. Surgery, which consisted of five cervical and four lumbar procedures, including intradural surgery in three patients, was uneventful in all cases without perioperative complication. The follow-up period ranged from 1 to 15 months (mean 5.22 months). The ODI score changed from severe disability (mean 46.89) preoperatively to minimal and moderate disability (mean 34.56) postoperatively. The SF-36 survey showed overall improved mental and physical health scores. Fusion was present in all patients with greater than 3 months follow up. CONCLUSIONS: The OP-1 putty appears to be safe and effective in promoting spinal arthrodesis in patients in whom adverse medical risk factors exist.

Adult↗
PubMed2002

Electrical stimulation as an adjunct to spinal fusion: a meta-analysis of controlled clinical trials.

This study was a meta-analysis to examine whether electrical stimulation has a specific effect on spinal fusion. Little evidence exists on the efficacy of electrical stimulation for improving fusion rate of spinal fusion surgery. Using MEDLINE (1966-2000) and EMBASE (1985-1999), a search for articles was carried out using the Medical Subject Headings: (1) electric stimulation or electromagnetic fields, (2) spinal fusion, (3) controlled or clinical trial, and (4) human. Data were extracted from all the hit articles and additionally collected from appropriate journal lists. A total of five randomized controlled trials (RCT) on bones assessing healing of spinal fusion were identified and scored on methodological quality. All the identified studies reported positive findings, but the quality score of each trial showed wide flaws. Because of relatively homogenous subjects who had spine fusion and radiographic assessment from these studies, pooling of the data was able to be performed. Excluding one trial with the lowest score, the combined results of four trials, whose major endpoints were the success rate of the fusion, revealed a statistically significant effect of electrical stimulation with various techniques, but the selected trials still showed wide variation in view of stimulation modalities and treatment protocol. The pooled result of the studies in this review revealed the efficacy of electrical stimulation based on proved methodological quality. As problems on therapeutic modality and protocol remain, there is a further need for improvement in design to constitute acceptable proof and to establish treatment programs that better demonstrate electrical stimulation effects on spinal fusion.

Combined Modality Therapy↗
PubMed2004

Lumbar spinal fusion. Outcome in relation to surgical methods, choice of implant and postoperative rehabilitation.

Chronic low back pain (CLBP) has become one of the most common causes of disability in adults under 45 years of age and is consequently one of the most common reasons for early retirement in industrialised societies. Accordingly, CLBP represents an expensive drain on society's resources and is a very challenging area for which a consensus for rational therapy is yet to be established. The spinal fusion procedure was introduced as a treatment option for CLBP more than 70 years ago. However, few areas of spinal surgery have caused so much controversy as spinal fusion. The literature reveals divergent opinions about when fusion is indicated and how it should be performed. Furthermore, the significance of the role of postoperative rehabilitation following spinal fusion may be underestimated. There exists no consensus on the design of a program specific for rehabilitation. Ideally, for any given surgical procedure, it should be possible to identify not only possible complications relative to a surgical procedure, but also what symptoms may be expected, and what pain behaviour may be expected of a particular patient. The overall aims of the current studies were: 1) to introduce patient-based functional outcome evaluation into spinal fusion treatment; 2) to evaluate radiological assessment of different spinal fusion procedures; 3) to investigate the effect of titanium versus stainless steel pedicle screws on mechanical fixation and bone ingrowth in lumbar spinal fusion; 4) to analyse the clinical and radiological outcome of different lumbar spinal fusion techniques; 5) to evaluate complications and re-operation rates following different surgical procedures; and 6) to analyse the effect of different rehabilitation strategies for lumbar spinal fusion patients. The present thesis comprises 9 studies: 2 clinical retrospective studies, 1 clinical prospective case/reference study, 5 clinical randomised prospective studies and 1 animal study (Mini-pigs). In total, 594 patients were included in the investigation from 1979 to 1999. Each had prior to inclusion at least 2 years of CLBP and had therefore been subjected to most of the conservative treatment leg pain, due to localized isthmic spondylolisthesis grades I-II or primary or secondary degeneration. PATIENT-BASED FUNCTIONAL OUTCOME: Patients' self-reported parameters should include the impact of CLBP on daily activity, work and leisure time activities, anxiety/depression, social interests and intensity of back and leg pain. Between 1993 and 2003 approximately 1400 lumbar spinal fusion patients completed the Dallas Pain Questionnaire under prospective design studies. In 1996, the Low Back Pain Rating scale was added to the standard questionnaire packet distributed among spinal fusion patients. In our experience, these tools are valid instruments for clinical assessment of candidates for spinal fusion procedures. RADIOLOGICAL ASSESSMENT: It is extremely difficult to interpret radiographs of both lumbar posterolateral fusion and anterior interbody fusion. Plain radiographs are clearly not the perfect media for analysis of spinal fusion, but until new and better diagnostic methods are available for clinical use, radiographs will remain the golden standard. Therefore, the development of a detailed reliable radiographic classification system is highly desirable. The classification used in the present thesis for the evaluation of posteroalteral spinal fusion, both with and without instrumentation, demonstrated good interobserver and intraobserver agreement. The classification showed acceptable reliability and may be one way to improve interstudy and intrastudy correlation of radiologic outcomes after posterolateral spinal fusion. Radiology-based evaluation of anterior lumbar interbody fusion is further complicated when cages are employed. The use of different cage designs and materials makes it almost impossible to establish a standard radiological classification system for anterior fusions. BONE-SCREW INTERFACE: Mechanical binding at the bone-screw interface was significantly greater for titanium pedicle screws than it was for stainless steel. This could be explained by the fact that the titanium screws had superior bone on-growth. There was no correlation between screw removal torques and pull-out strength. Clinically, the use of titanium and titanium-alloy pedicle screws may be preferable for osteoporotic patients and those with decreased osteogenesis. OUTCOME: The present series of studies observed significant long-term functional improvement for approximately 70% of patients who had undergone lumbar spinal fusion procedure. Solid fusion as determined from radiographs ranged from 52% to 92% depending on the choice of surgical procedure. The choice of surgical procedure should relate to the diagnosis, as patients with isthmic spondylolisthesis (Grades I and II) are best served with posterolateral fusion without instrumentation, and patients with disc degeneration seem to gain most from instrumented posterolateral fusion or circumferential fusion. COMPLICATIONS: The number of perioperative complications increased with the use of pedicle screw systems to support posterolateral fusions and increased further with the use of circumferential fusions. There was no significant association between outcome result and perioperative complications. The risk of reoperation within 2 years after the spinal fusion procedure was, however, significantly lower for those who had received circumferential fusion in comparison to posterolateral fusion with instrumentation. Furthermore, the risk of non-union was found to be significantly lower for patients who had received circumferential fusion as compared to posterolateral fusion with and without instrumentation. The complications of sexual dysfunction and fusion at non-intended levels were found to be significant but without influence on the overall outcome. REHABILITATION: The patients in the Back-café group performed a succession of many daily tasks significantly better and moreover had less pain compared with both the Video and Training groups 2 years after lumbar spinal fusion. The Video group had significantly greater treatment demands outside the hospital system. This study demonstrates the importance of the inclusion of coping schemes and questions the role of intensive exercises in a rehabilitation program for spinal fusion patients.

Activities of Daily Living↗