Sigurd Berven

The Impact of Positive Sagittal Balance in Adult Spinal Deformity

Study Design. This study is a retrospective review of 752 patients with adult spinal deformity enrolled in a multicenter prospective database in 2002 and 2003. Patients with positive sagittal balance (N = 352) were further evaluated regarding radiographic parameters and health status measures, including the Scoliosis Research Society patient questionnaire, MOS short form-12, and Oswestry Disability Index. Objectives. To examine patients with adult deformity with positive sagittal balance to define parameters within that group that might differentially predict clinical impact. Summary of Background Data. In a multicenter study of 298 adults with spinal deformity, positive sagittal balance was identified as the radiographic parameter most highly correlated with adverse health status outcomes. Methods. Radiographic evaluation was performed according to a standarized protocol for 36-inch standing radiographs. Magnitude of positive sagittal balance and regional sagittal Cobb angle measures were recorded. Statistical correlation between radiographic parameters and health status measures were performed. Potentially confounding variables were assessed. Results. Positive sagittal balance was identified in 352 patients. The C7 plumb line deviation ranged from 1 to 271 mm. All measures of health status showed significantly poorer scores as C7 plumb line deviation increased. Patients with relative kyphosis in the lumbar region had significantly more disability than patients with normal or lordotic lumbar sagittal Cobb measures. Conclusions. This study shows that although even mildly positive sagittal balance is somewhat detrimental, severity of symptoms increases in a linear fashion with progressive sagittal imbalance. The results also show that kyphosis is more favorable in the upper thoracic region but very poorly tolerated in the lumbar spine.

Surgical versus nonsurgical therapy for lumbar spinal stenosis.

BACKGROUND Surgery for spinal stenosis is widely performed, but its effectiveness as compared with nonsurgical treatment has not been shown in controlled trials. METHODS Surgical candidates with a history of at least 12 weeks of symptoms and spinal stenosis without spondylolisthesis (as confirmed on imaging) were enrolled in either a randomized cohort or an observational cohort at 13 U.S. spine clinics. Treatment was decompressive surgery or usual nonsurgical care. The primary outcomes were measures of bodily pain and physical function on the Medical Outcomes Study 36-item Short-Form General Health Survey (SF-36) and the modified Oswestry Disability Index at 6 weeks, 3 months, 6 months, and 1 and 2 years. RESULTS A total of 289 patients were enrolled in the randomized cohort, and 365 patients were enrolled in the observational cohort. At 2 years, 67% of patients who were randomly assigned to surgery had undergone surgery, whereas 43% of those who were randomly assigned to receive nonsurgical care had also undergone surgery. Despite the high level of nonadherence, the intention-to-treat analysis of the randomized cohort showed a significant treatment effect favoring surgery on the SF-36 scale for bodily pain, with a mean difference in change from baseline of 7.8 (95% confidence interval, 1.5 to 14.1); however, there was no significant difference in scores on physical function or on the Oswestry Disability Index. The as-treated analysis, which combined both cohorts and was adjusted for potential confounders, showed a significant advantage for surgery by 3 months for all primary outcomes; these changes remained significant at 2 years. CONCLUSIONS In the combined as-treated analysis, patients who underwent surgery showed significantly more improvement in all primary outcomes than did patients who were treated nonsurgically. (ClinicalTrials.gov number, NCT00000411 [ClinicalTrials.gov].).

Correlation of radiographic parameters and clinical symptoms in adult scoliosis.

Study Design. This study is a retrospective review of the initial enrollment data from a prospective multicentered study of adult spinal deformity. Objectives. The purpose of this study is to correlate radiographic measures of deformity with patient-based outcome measures in adult scoliosis. Summary of Background Data. Prior studies of adult scoliosis have attempted to correlate radiographic appearance and clinical symptoms, but it has proven difficult to predict health status based on radiographic measures of deformity alone. The ability to correlate radiographic measures of deformity with symptoms would be useful for decision-making and surgical planning. Methods. The study correlates radiographic measures of deformity with scores on the Short Form-12, Scoliosis Research Society-29, and Oswestry profiles. Radiographic evaluation was performed according to an established positioning protocol for anteroposterior and lateral 36-inch standing radiographs. Radiographic parameters studied were curve type, curve location, curve magnitude, coronal balance, sagittal balance, apical rotation, and rotatory subluxation. Results. The 298 patients studied include 172 with no prior surgery and 126 who had undergone prior spine fusion. Positive sagittal balance was the most reliable predictor of clinical symptoms in both patient groups. Thoracolumbar and lumbar curves generated less favorable scores than thoracic curves in both patient groups. Significant coronal imbalance of greater than 4 cm was associated with deterioration in pain and function scores for unoperated patients but not in patients with previous surgery. Conclusions. This study suggests that restoration of a more normal sagittal balance is the critical goal for any reconstructive spine surgery. The study suggests that magnitude of coronal deformity and extent of coronal correction are less critical parameters.

Minimum clinically important difference in lumbar spine surgery patients: a choice of methods using the Oswestry Disability Index, Medical Outcomes Study questionnaire Short Form 36, and Pain Scales

BACKGROUND CONTEXT The impact of lumbar spinal surgery is commonly evaluated with three patient-reported outcome measures: Oswestry Disability Index (ODI), the physical component summary (PCS) of the Short Form of the Medical Outcomes Study (SF-36), and pain scales. A minimum clinically important difference (MCID) is a threshold used to measure the effect of clinical treatments. Variable threshold values have been proposed as MCID for those instruments despite a lack of agreement on the optimal MCID calculation method. PURPOSE This study has three purposes. First, to illustrate the range of values obtained by common anchor-based and distribution-based methods to calculate MCID. Second, to determine a statistically sound and clinically meaningful MCID for ODI, PCS, back pain scale, and leg pain scale in lumbar spine surgery patients. Third, to compare the discriminative ability of two anchors: a global health assessment and a rating of satisfaction with the results of the surgery. STUDY DESIGN This study is a review of prospectively collected patient-reported outcomes data. PATIENT SAMPLE A total of 454 patients from a large database of surgeries performed by the Lumbar Spine Study Group with a 1-year follow-up on either ODI or PCS were included in the study. OUTCOME MEASURES Preoperative and 1-year postoperative scores for ODI, PCS, back pain scale, leg pain scale, health transition item (HTI) of the SF-36, and Satisfaction with Results scales. METHODS ODI, SF-36, and pain scales were administered before and 1 year after spinal surgery. Several candidate MCID calculation methods were applied to the data and the resulting values were compared. The HTI of the SF-36 was used as the anchor and compared with a second anchor (Satisfaction with Results scale). RESULTS Potential MCID calculations yielded a range of values: fivefold for ODI, PCS, and leg pain, 10-fold for back pain. Threshold values obtained with the two anchors were very similar. CONCLUSIONS The minimum detectable change (MDC) appears as a statistically and clinically appropriate MCID value. MCID values in this sample were 12.8 points for ODI, 4.9 points for PCS, 1.2 points for back pain, and 1.6 points for leg pain.

Intervertebral Disc Cell Therapy for Regeneration: Mesenchymal Stem Cell Implantation in Rat Intervertebral Discs

This study explores the use of mesenchymal stem cells (MSCs) for intervertebral disc regeneration. We used an in vivo model to investigate the feasibility of exogenous cell delivery, retention, and survival in the pressurized disc space. MSC injection into rat coccygeal discs was performed using 15% hyaluronan gel as a carrier. Injections of gel with or without MSCs were performed. Immediately after injection, fluorescently labeled stem cells were visible on sections of cell-injected discs. Seven and 14 days after injection, stem cells were still present within the disc, but their numbers were significantly decreased. At 28 days, a return to the initial number of injected cells was observed, and viability was 100%. A trend of increased disc height compared to blank gel suggests an increase in matrix synthesis. The results indicate that MSCs can maintain viability and proliferate within the rat intervertebral disc.

A novel classification system for spinal instability in neoplastic disease: an evidence-based approach and expert consensus from the Spine Oncology Study Group.

Study Design. Systematic review and modified Delphi technique. Objective. To use an evidence-based medicine process using the best available literature and expert opinion consensus to develop a comprehensive classification system to diagnose neoplastic spinal instability. Summary of Background Data. Spinal instability is poorly defined in the literature and presently there is a lack of guidelines available to aid in defining the degree of spinal instability in the setting of neoplastic spinal disease. The concept of spinal instability remains important in the clinical decision-making process for patients with spine tumors. Methods. We have integrated the evidence provided by systematic reviews through a modified Delphi technique to generate a consensus of best evidence and expert opinion to develop a classification system to define neoplastic spinal instability. Results. A comprehensive classification system based on patient symptoms and radiographic criteria of the spine was developed to aid in predicting spine stability of neoplastic lesions. The classification system includes global spinal location of the tumor, type and presence of pain, bone lesion quality, spinal alignment, extent of vertebral body collapse, and posterolateral spinal element involvement. Qualitative scores were assigned based on relative importance of particular factors gleaned from the literature and refined by expert consensus. Conclusion. The Spine Instability Neoplastic Score is a comprehensive classification system with content validity that can guide clinicians in identifying when patients with neoplastic disease of the spine may benefit from surgical consultation. It can also aid surgeons in assessing the key components of spinal instability due to neoplasia and may become a prognostic tool for surgical decision-making when put in context with other key elements such as neurologic symptoms, extent of disease, prognosis, patient health factors, oncologic subtype, and radiosensitivity of the tumor.

Outcome and Complications of Long Fusions to the Sacrum in Adult Spine Deformity : Luque-Galveston, Combined Iliac and Sacral Screws, and Sacral Fixation

Study Design. A retrospective study of adults with long fusion to the sacrum using three different fixations was performed. Objective. To compare the long-term clinical results and complications associated with three methods of lumbosacral fixation for adult spine deformities: Luque-Galveston, combined iliac and sacral screws, and sacral screws. Summary of Background Data. The preferred technique for long fusion to the sacrum is controversial, and surgery for adult deformity is fraught with significant technical difficulties and high complication rates. No clinical study compares the long-term outcome of long fusion to the sacrum using these different methods of lumbosacral fixation. Methods. This study included 54 consecutive patients who underwent elective combined anterior and posterior surgical reconstruction for adult spine deformity with a minimum follow-up period of 2 years. The patients were divided into three groups on the basis of the surgical method used for the posterior spine instrumentation. Group 1 consisted of 11 patients with smooth L-rod and segmental sublaminar wire instrumentation (Luque-Galveston technique). Group 2 consisted of 36 patients with posterior Isola segmental instrumentation and combined iliac and sacral screws. Group 3 consisted of 12 patients with Isola segmental instrumentation using bicortical sacral screws. Five patients were revised to another fixation group, giving a total of 59 cases. Radiographic, clinical results, and long-term outcome data were obtained using the modified Scoliosis Research Society (SRS) outcome instrument. Results. There were 26 late complications. Pseudarthrosis developed in 10 patients, requiring revision surgery: 4 (36%) in the Group 1, 5 (14%) in Group 2, and 1 (8.5%) in Group 3. Comparison of the modified SRS outcomes showed no difference among the groups. The average SRS grand total score was 73.4% for Group 1, 70.9% for Group 2, and 62.6% for Group 3. Overall, 76% of the patients were satisfied with their outcome. The presence of perioperative complications or pseudarthrosis significantly correlated with a lower satisfaction score (P = 0.012 and P = 0.048, respectively). Sagittal plane decompensation significantly correlated with a higher pain score (P = 0.035). Patients with prior surgeries scored lower on the self-image questions than patients with no prior surgery (P = 0.007). Conclusions. Attention to sagittal balance is critical in these patients. Revision surgery is as safe and effective as primary surgery. According to the current findings, the Luque-Galveston fixation technique has an unacceptably high rate of pseudarthrosis, and this method is not recommended for adult deformities. Currently, the authors are using bicortical and triangulated sacral screws with an anterior interbody support in patients with good bone stock, but only when the spine balance is restored. Otherwise, they recommend using iliac fixation, although there is a higher rate of painful hardware, requiring removal.

Surgical versus nonoperative treatment for lumbar spinal stenosis four-year results of the Spine Patient Outcomes Research Trial.

Study Design. Randomized trial and concurrent observational cohort study. Objective. To compare 4 year outcomes of surgery to nonoperative care for spinal stenosis. Summary of Background Data. Surgery for spinal stenosis has been shown to be more effective compared to nonoperative treatment over 2 years, but longer-term data have not been analyzed. Methods. Surgical candidates from 13 centers in 11 US states with at least 12 weeks of symptoms and confirmatory imaging were enrolled in a randomized cohort (RC) or observational cohort (OC). Treatment was standard decompressive laminectomy or standard nonoperative care. Primary outcomes were SF-36 bodily pain (BP) and physical function scales and the modified Oswestry Disability index assessed at 6 weeks, 3 months, 6 months, and yearly up to 4 years. Results. A total of 289 patients enrolled in the RC and 365 patients enrolled in the OC. An as-treated analysis combining the RC and OC and adjusting for potential confounders found that the clinically significant advantages for surgery previously reported were maintained through 4 years, with treatment effects (defined as mean change in surgery group minus mean change in nonoperative group) for bodily pain 12.6 (95% confidence interval [CI], 8.5–16.7); physical function 8.6 (95% CI, 4.6–12.6); and Oswestry Disability index −9.4 (95% CI, −12.6 to −6.2). Early advantages for surgical treatment for secondary measures such as bothersomeness, satisfaction with symptoms, and self-rated progress were also maintained. Conclusion. Patients with symptomatic spinal stenosis treated surgically compared to those treated nonoperatively maintain substantially greater improvement in pain and function through 4 years.

Spinal Instability Neoplastic Score: An Analysis of Reliability and Validity From the Spine Oncology Study Group

PURPOSE Standardized indications for treatment of tumor-related spinal instability are hampered by the lack of a valid and reliable classification system. The objective of this study was to determine the interobserver reliability, intraobserver reliability, and predictive validity of the Spinal Instability Neoplastic Score (SINS). METHODS Clinical and radiographic data from 30 patients with spinal tumors were classified as stable, potentially unstable, and unstable by members of the Spine Oncology Study Group. The median category for each patient case (consensus opinion) was used as the gold standard for predictive validity testing. On two occasions at least 6 weeks apart, each rater also scored each patient using SINS. Each total score was converted into a three-category data field, with 0 to 6 as stable, 7 to 12 as potentially unstable, and 13 to 18 as unstable. RESULTS The κ statistics for interobserver reliability were 0.790, 0.841, 0.244, 0.456, 0.462, and 0.492 for the fields of location, pain, bone quality, alignment, vertebral body collapse, and posterolateral involvement, respectively. The κ statistics for intraobserver reliability were 0.806, 0.859, 0.528, 0.614, 0.590, and 0.662 for the same respective fields. Intraclass correlation coefficients for inter- and intraobserver reliability of total SINS score were 0.846 (95% CI, 0.773 to 0.911) and 0.886 (95% CI, 0.868 to 0.902), respectively. The κ statistic for predictive validity was 0.712 (95% CI, 0.676 to 0.766). CONCLUSION SINS demonstrated near-perfect inter- and intraobserver reliability in determining three clinically relevant categories of stability. The sensitivity and specificity of SINS for potentially unstable or unstable lesions were 95.7% and 79.5%, respectively.

Risk-benefit assessment of surgery for adult scoliosis: an analysis based on patient age.

Study Design. Retrospective review of a prospective, multicenter database. Objective. The purpose of this study was to assess whether elderly patients undergoing scoliosis surgery had an incidence of complications and improvement in outcome measures comparable with younger patients. Summary of Background Data. Complications increase with age for adults undergoing scoliosis surgery, but whether this impacts the outcomes of older patients is largely unknown. Methods. This is a retrospective review of a prospective, multicenter spinal deformity database. Patients complete the Oswestry Disability Index (ODI), SF-12, Scoliosis Research Society-22 (SRS-22), and numerical rating scale (NRS; 0–10) for back and leg pain. Inclusion criteria included age 25 to 85 years, scoliosis (Cobb ≥ 30°), plan for scoliosis surgery, and 2-year follow-up. Results. Two hundred six of 453 patients (45%) completed 2-year follow-up, which is distributed among age groups as follows: 25 to 44 (n = 47), 45 to 64 (n = 121), and 65 to 85 (n = 38) years. The percentages of patients with 2-year follow-up by age group were as follows: 25 to 44 (45%), 45 to 64 (48%), and 65 to 85 (40%) years. These groups had perioperative complication rates of 17%, 42%, and 71%, respectively (P < 0.001). At baseline, elderly patients (65–85 years) had greater disability (ODI, P = 0.001), worse health status (SF-12 physical component score (PCS), P < 0.001), and more severe back and leg pain (NRS, P = 0.04 and P = 0.01, respectively) than younger patients. Mean SRS-22 did not differ significantly at baseline. Within each age group, at 2-year follow-up there were significant improvements in ODI (P ⩽ 0.004), SRS-22 (P ⩽ 0.001), back pain (P < 0.001), and leg pain (P ⩽ 0.04). SF-12 PCS did not improve significantly for patients aged 25 to 44 years but did among those aged 45 to 64 (P < 0.001) and 65 to 85 years (P = 0.001). Improvement in ODI and leg pain NRS were significantly greater among elderly patients (P = 0.003, P = 0.02, respectively), and there were trends for greater improvements in SF-12 PCS (P = 0.07), SRS-22 (P = 0.048), and back pain NRS (P = 0.06) among elderly patients, when compared with younger patients. Conclusion. Collectively, these data demonstrate the potential benefits of surgical treatment for adult scoliosis and suggest that the elderly, despite facing the greatest risk of complications, may stand to gain a disproportionately greater improvement in disability and pain with surgery.