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, includ

The Impact of Positive Sagittal Balance in Adult Spinal Deformity

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.

Correlation of radiographic parameters and clinical symptoms in adult scoliosis

STUDY DESIGN Prospective radiographic and clinical analysis. OBJECTIVE Investigate the relationship between spino-pelvic parameters and patient self reported outcomes on adult subjects with spinal deformities. SUMMARY OF BACKGROUND DATA It is becoming increasingly recognized that the study of spinal alignment should include pelvic position. While pelvic incidence determines lumbar lordosis, pelvic tilt (PT) is a positional parameter reflecting compensation to spinal deformity. Correlation between plumbline offset (sagittal vertical axis [SVA]) and Health Related Quality of Life (HRQOL) measures has been demonstrated, but such a study is lacking for PT. METHODS This prospective study was carried out on 125 adult patients suffering from spinal deformity (mean age: 57 years). Full-length free-standing radiographs including the spine and pelvis were available for all patients. HRQOL instruments included: Oswestry Disability Index, Short Form-12, Scoliosis Research Society. Correlation analysis between radiographic spinopelvic parameters and HRQOL measures was pursued. RESULTS Correlation analysis revealed no significance pertaining to coronal plane parameters. Significant sagittal plane correlations were identified. SVA and truncal inclination measured by T1 spinopelvic inclination (T1-SPI) (angle between T1-hip axis and vertical) correlated with: Scoliosis Research Society (appearance, activity, total score), Oswestry Disability Index, and Short Form-12 (physical component score). Correlation coefficients ranged from 0.42 < r < 0.55 (P < 0.0001). T1-SPI revealed greater correlation with HRQOL compared to SVA. PT showed correlation with HRQOL (0.28 < r < 0.42) and with SVA (r = 0.64, P < 0.0001). CONCLUSION This study confirms that pelvic position measured via PT correlates with HRQOL in the setting of adult deformity. High values of PT express compensatory pelvic retroversion for sagittal spinal malalignment. This study also demonstrates significant T1-SPI correlation with HRQOL measures and outperforms SVA. This parameter carries the advantage of being an angular measurement which avoids the error inherent in measuring offsets in noncalibrated radiographs.

Pelvic tilt and truncal inclination: two key radiographic parameters in the setting of adults with spinal deformity.

Periprosthetic osteolysis-bone loss in the vicinity of a prosthesis-is the most serious problem limiting the longevity of artificial joints. It is caused by bone-resorptive responses to wear particles originating from the articulating surface. This study investigated the effects of graft polymerization of our original biocompatible phospholipid polymer 2-methacryloyloxyethyl phosphorylcholine (MPC) onto the polyethylene surface. Mechanical studies using a hip-joint simulator revealed that the MPC grafting markedly decreased the friction and the amount of wear. Osteoclastic bone resorption induced by subperiosteal injection of particles onto mouse calvariae was abolished by the MPC grafting on particles. MPC-grafted particles were shown to be biologically inert by culture systems with respect to phagocytosis and resorptive cytokine secretion by macrophages, subsequent expression of receptor activator of NF-kappaB ligand in osteoblasts, and osteoclastogenesis from bone marrow cells. From the mechanical and biological advantages, we believe that our approach will make a major improvement in artificial joints by preventing periprosthetic osteolysis.

Surface grafting of artificial joints with a biocompatible polymer for preventing periprosthetic osteolysis

Macrophage responses to silk.

STUDY DESIGN Scoliosis patients were prospectively x-rayed in three positions with independent analysis OBJECTIVES To determine if one positioning technique provides superior visualization of critical landmarks (C7, T2, T12, L5-S1) and to determine any position dependent variations in regional measures or sagittal balance SUMMARY OF BACKGROUND DATA Different techniques for positioning patient's arms are used for 36" lateral radiograph with no data on relative effects METHODS A total of 25 scoliosis patients were prospectively studied with 36" lateral radiographs in three positions varying arm location (straight out, partially flexed, and the "clavicle" position) Films were analyzed independently by three surgeons Vertebral landmarks were scored for clarity; and lordosis, kyphosis, and global balance were analyzed Statistical analysis was done with a General Estimating Equations model RESULTS The overall visualization score for the clavicle position was superior to either the 60 degrees or 90 degrees positions (clavicle vs 60 degrees, P < 00001; clavicle vs 90 degrees, P < 00003) Analysis of vertebral landmarks showed significantly better visualization of T2 with clavicle versus 90 degrees (P < 0047), better visualization of T12 with clavicle versus either 60 degrees (P < 0006) or 90 degrees (P < 0049), and better visualization of L5-S1 with clavicle versus 90 degrees (P < 002) Regional measures showed no differences, but sagittal balance was significantly more positive in the 60 degrees position than either clavicle (P < 004) or 90 degrees (P < 0015) CONCLUSIONS The clavicle position for obtaining lateral 36" radiographs produces significantly better overall visualization of critical vertebral landmarks Regional measures do not differ between the three positions, but global balance is more positive with the 60 degrees position Clinically, the clavicle position may result in more accurate radiographic measures and may minimize repeated radiograph exposures

Is there an optimal patient stance for obtaining a lateral 36" radiograph? A critical comparison of three techniques.

The size and morphology of particulate wear debris retrieved from tissues around 18 failed total knee replacements (TKR) were characterized. Interfacial membranes from nine cemented and nine uncemented TKR were harvested from below the tibial components during revision surgery. Wear debris were extracted using papain and potassium hydroxide digestion. Ultrahigh molecular weight polyethylene (UHMWPE) particles from around cemented or uncemented TKR were similar in size and morphology. The mean size was 1.7 ± 0.7 μm with a range of 0.1–18 μm. Thirty-six percent of the particles were less than 1 μm and 90% were less than 3 μm. Morphologically the particles were predominantly spherical with occasional fibrillar attachments and flakes. Particles from TKR were greater than threefold larger than previously characterized particles from total hip replacements, which were 0.5 μm in mean size. Differences in joint conformity and wear patterns between the hip and knee articulations may explain the disparity in size of the wear debris. Since particle size represents an important variable influencing the magnitude of the biological response, it is possible that in vivo the larger TKR debris results in a diminished mediator release, which in turn may account for the lower incidence of osteolysis and aseptic loosening in some designs of TKR. © 2000 John Wiley & Sons, Inc. J Biomed Mater Res (Appl Biomater) 53: 100–110, 2000

Quantitative analysis of ultrahigh molecular weight polyethylene (UHMWPE) wear debris associated with total knee replacements.

Study Design A retrospective study of blood transfusion practices after posterior lumbar spine surgery was performed Objectives To determine the overall use rate of autologous blood donations for different spine surgeries, and to identify the risk of requiring additional allogeneic blood transfusions Summary of Background Data In an attempt to avoid allogeneic blood transfusions and its associated risks, patients frequently are asked to donate autologous blood before many efective spine surgeries There is a lack of published data on the use rate for these autoiogous blood donations, and on their ability to prevent allogeneic blood exposure Methods A retrospective review of hospital charts and blood bank records was conducted on 191 consecutive patients who had undergone three categories of lumbar spine surgery: laminectomy alone, laminectomy with a noninstrumented posteroiateral fusion, and laminectomy with an instrumented posteroiateral fusion Results Nearly 80% of the autologous blood donated by patients who underwent simple laminectomies was wasted However, the vast majority (70-90%) of patients who underwent fusion used their autologous blood In the patients who underwent fusion, autologous blood donations decreased the risk of aliogenic blood transfusions by 75% in noninstrumented fusions and 50% in instrumented fusions, as compared with the patients who elected not to donate blood before the fusion (P < 005) A substantial number of patients who underwent instrumented fusions (nearly 40%) required additional alloge neic blood transfusions despite predonation of blood Conclusions Autologous blood donations are indeed advantageous n decreasing aliogeneic blood usage of patients undergoing fusion, but additional methods of blood conservation (intraoperative salvage and preoper ative erythropoietin) seem necessary to diminish the al logeneic blood requirements further, especially in those patients undergoing instrumented lumber fusion

Allogeneic transfusion requirements after autologous donations in posterior lumbar surgeries.

A series of early femoral component failures prompted a detailed retrospective clinical and radiographic review of 176 hybrid cemented total hip arthroplasties using a polymethyl-methacrylate coated femoral prosthesis. All surgeries were performed using third generation cement techniques. Average length of followup was 6.3 years (range, 3-12 years). Twenty-one patients died, and one underwent revision surgery because of sepsis. Of the remaining 154 total hip arthroplasties, 23 (15%) of the femoral components failed (21 revised, two definitely loose). The average time to revision was 3.9 years. None of the acetabular components failed. Comparison between the failure and nonfailure groups revealed that poor cement mantles (Grades C or D) with distal cement mantle deficiencies were statistically significant predictors of femoral failure. The most common mechanism of failure was progressive, circumferential cement-bone interface osteolysis with relative preservation of the cement-metal interface. Debonding of the cement column from the prosthesis was a late finding and occurred in only 45% of failed cases. Incorporating the techniques of centralization and centrifugation significantly improved clinical results. Strengthening of the cement-prosthesis interface may magnify the deleterious effects of a poor cement mantle and predisposes the cement-bone interface to failure.

Charles W. Cha

Papers

Is there an optimal patient stance for obtaining a lateral 36" radiograph? A critical comparison of three techniques.

Quantitative analysis of ultrahigh molecular weight polyethylene (UHMWPE) wear debris associated with total knee replacements.

Allogeneic transfusion requirements after autologous donations in posterior lumbar surgeries.

Failure of Total Hip Arthroplasty With a Precoated Prosthesis: 4- to 11-year Results