Development and Validation of the iDI: A Short Self-Rating Disability Instrument for Low Back Pain Disorders.

STUDY DESIGN: Cross-sectional and longitudinal validation study. OBJECTIVE: Development and validation of a short, reliable, and valid questionnaire for the assessment of low back pain-related disability. METHODS: The iDI was created in a stepwise procedure: (1) its development was based on the literature and theoretical consideration; (2) outcome data were collected and evaluated in a pilot study; (3) final validations were performed based on an international multicenter spine surgery outcome study including 514 patients; (4) the iDI was programmed for a tablet computer (iPad) and tested for its clinical practicability. RESULTS: The final version of the iDI comprises of 8 simple questions related to different aspects of disability with a 5-point Likert-type answer scale. The iDI compared very well to the Oswestry Disability Index in terms of reliability and validity. The iDI was demonstrated to be suitable for data assessment on a tablet computer (iPad). CONCLUSIONS: The iDI is a short, valid, and practicable tool that facilitates routine quality assessment in terms of low back pain-related disability.

Does intrawound application of vancomycin influence bone healing in spinal surgery?

PURPOSE: Surgical site infections represent a major complication of spinal surgery. The application of lyophilised vancomycin into the wound is reported to significantly decrease infection rates. As concentrations applied locally can exceed the minimal bacterial inhibitory concentration for more than a 1000-fold, toxic side effects on local tissue may be possible. METHODS: Primary osteoblast cell cultures were generated from bone tissue samples of 10 patients. Samples were incubated in absence or presence of either 3, 6 or 12 mg/cm(2) vancomycin according to a planned phase I clinical trial protocol. Changes in pH, osteoblast migration, proliferation and viability were analysed. Alkaline phosphatase as well as mineralisation patterns was studied. RESULTS: The application of more than 3 mg/cm(2) vancomycin induced a decline of pH. The migration potential of osteoblasts was decreased from 100% (control samples) to zero (12 mg/cm(2) vancomycin) in a dose-dependant manner. Cell proliferation was significantly inhibited at dosages above 3 mg/cm(2). Significant cell death was observed if the dosage applied exceeded 6 mg/cm(2). The synthesis of alkaline phosphatase was markedly reduced in all dosages applied and calcium deposition was significantly decreased in dosages above 3 mg/cm(2). CONCLUSION: As bone remodelling requires the immigration, proliferation and differentiation of osteoblasts at the fusion site, high dosages of intrawound vancomycin might interfere with regenerative processes and increase the risk of non-union. To allow an appropriate balance of infection risk and the risk of non-union, the minimal local concentration required should be determined by controlled in vivo studies.

Influence of intradiscal medication on nucleus pulposus cells.

BACKGROUND CONTEXT: Eugene Carragee was the first to prove that provocative discography may contribute to intervertebral disc degeneration. Disc degeneration can be induced either by mechanical trauma caused by the puncturing needle or as a pharmacological effect of the drugs instilled into the disc. PURPOSE: The aim of this study was to test the influence of cortisone, lidocaine, and iopamidol on nucleus pulposus cells under an in vitro setting. STUDY DESIGN: Controlled in vitro study is the design type. METHODS: The nucleus pulposus was excised from 12 bovine tail intervertebral discs and monolayer cell cultures were generated. The cultures were divided into four sample groups and incubated in either standard cell culture medium (control group) or medium supplemented with the test substances. The dose rate was adapted based on a total dose of 3 mL iopamidol, 1 mL lidocaine, and 10 mg cortisone per nucleus pulposus. Cell count, viability, proliferation, and differentiation features were analyzed. The study was supported by DePuy. No conflicts of interest arise from this support. RESULTS: After 24 hours, a significant decrease in cell counts was observed in all three test groups. Population doubling time was 16 hours in the control group cultured in standard medium and increased to 21 hours (cortisone), 25 hours (iopamidol), and 38 hours (lidocaine) after incubation in discography medication (p<.001). Cell viability was slightly, but not significantly decreased in all medication groups. Cells incubated in Lidocaine were significantly smaller (p<.01) and showed clearly reduced pseudopodia formation. Incubation in lidocaine and iopamidol also significantly reduced glycosaminoglycan synthesis. CONCLUSION: Although only a small decrease in cell viability was observed in all three substances tested, cell count and proliferation decreased significantly. Incubation in lidocaine inhibited pseudopodia formation and might therefore interfere with intercellular signalling and cell migration. Glycosaminoglycan synthesis was significantly decreased after contact with lidocaine as well as Iopamidol. These observations suggest that all three medications tested might interfere with biological repair mechanisms of the intervertebral disc and therefore contribute to a further degeneration.

Implant survival analysis and failure modes of the X-Stop interspinous distraction device.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To review the clinical outcome, implant survivorship and reasons for failure after X-Stop implantation. SUMMARY OF BACKGROUND DATA: Conflicting data exist concerning clinical outcome of the X-Stop interspinous spacer and little information is being published about implant survivorship and the need for revision surgery. METHODS: This retrospective review evaluated 46 patients who underwent implantation of the X-Stop interspinous spacer for the treatment of neurogenic claudication. After a mean follow-up of 40 months, pain levels, 36-Item Short Form Health Survey (SF-36), Oswestry Disability Index (ODI), and the need for subsequent surgery were assessed and a Kaplan-Meier survivorship analysis was performed. RESULTS: Within the follow-up period, the revision rate was found to be 30.4%. Lack of improvement at 6-week follow-up correlated well with subsequent revision surgery, which predominantly took place within 12 months after the index surgery. In patients who did not need to undergo revision surgery, clinical outcome parameters improved significantly. Kaplan-Meier survivorship analysis predicted an implant survival probability of 0.68 at 48 months postoperatively. CONCLUSION: Clinical outcome after X-Stop implantation might be considerably less favorable than when it was being published previously. Patient selection might be a reason for early revision surgery. More criteria for better X-Stop indications might be needed.

Autografts for spinal fusion: osteogenic potential of laminectomy bone chips and bone shavings collected via high speed drill.

In case of revision or minimal invasive spinal surgery, the amount of autograft possibly harvested from the lamina and the spinous processes is limited. Ekanayake and Shad (Acta Neurochir 152:651-653, 2010) suggest the application of bone shavings harvested via high speed burr additionally or instead, but so far no data regarding their osteogenic potential exist. Aim of the study was to compare the osteogenic potential of bone chips and high speed burr shavings, and to evaluate the applicability of bone shavings as an autograft for spinal fusion. Bone chips and shavings from 14 patients undergoing spinal decompression surgery were analyzed using in vitro tissue culture methods. Osteoblast emigration and proliferation, viability and mineralization were investigated and histological evaluation was performed. Bone chips from all patients showed successful osteoblast emigration after average 5.5 days. In contrast, only 57% of the corresponding bone shavings successfully demonstrated osteoblast emigration within an average time span of 14.8 days. Average osteoblast mobilisation was 1.25 × 10(6) cells per gram from bone chips and 1.73 × 10(5) cells per gram from the corresponding bone shavings. No difference was observed regarding cell viability, but population doubling times of bone chip cultures were significantly lower (50.5 vs. 121 h) and mineralization was observed in osteoblasts derived from bone chips only. Although some authors suggest the general applicability of laminectomy bone shavings as autografts for spinal fusion, autologous bone grafts obtained from laminectomy bone chips are superior in terms of cell delivery, cell proliferation and mineralization.

[Keel-based lumbar total disk replacement: Prodisc-L and Prodisc-O]. / Kielbasierte lumbale Bandscheibenprothesen: Prodisc-L und Prodisc-O.

OBJECTIVE: Improvement of chronic low back pain caused by degenerative disc disease. Maintenance of motion in the treated segment. Reduction of possible adjacent-segment degeneration. INDICATIONS: Chronic low back pain, resistant to conservative therapy due to painful degeneration of the intervertebral disks ("degenerative disk disease"). CONTRAINDICATIONS: Spondylolisthesis, scoliosis, osteoporosis, infection, spinal stenosis, degeneration of the vertebral articulations, (pathologic) fractures. SURGICAL TECHNIQUE: The intervertebral disk is removed via an anterior (Prodisc- L) or anterolateral (Prodisc-O) approach. The segment is sufficiently mobilized, if necessary, by release of the posterior longitudinal ligament. After end-plate preparation, a groove for the keel is chiseled, the end plates are inserted, and the inlay is securely locked in place. POSTOPERATIVE MANAGEMENT: Careful beginning of food intake for prophylaxis of ileus. Early mobilization starting on the 1st day after surgery. RESULTS: From April 2002 to February 2008, 87 Prodisc-L intervertebral disk prostheses were implanted in 71 patients (43 women, 28 men, average age 45 years). Clinical evaluation was based on the visual analog scale (VAS), the Oswestry Disability Index (ODI), and the SF-36 questionnaire. Follow-up assessment also included radiographic views of the lumbar spine in two planes in flexion and extension and standing. The follow-up interval for all patients was at least 1 year and 2 years for 62 patients. After 2 years, 42 patients were very satisfied with the operation, 13 patients were satisfied, and seven patients were less satisfied. The clinical parameters recorded on the VAS, ODI, and SF-36 improved from 7.5 to 3.5 (VAS), 46.0 to 22.9 (ODI), and 30.5 to 44.8 (SF-36, Physical Component Summary Score) from the time of preoperative assessment to the 2-year follow-up.

Life quality after instrumented lumbar fusion in the elderly.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To review the clinical outcome on elderly patients after spinal instrumented fusion. SUMMARY OF BACKGROUND DATA: Although lumbar fusion in elderly patients has increased rapidly, there are only few and conflicting results regarding the clinical outcome. METHODS: This retrospective review evaluated 195 patients aged 70 to 89 who underwent lumbar spinal fusion. All 195 patients had follow-ups after 6 weeks, 1 year, and 2 years, including clinical evaluation as well as visual analog scale score, Oswestry Disability Index, and Short Form health survey. RESULTS: Elderly patients benefit from spinal fusion. Back and leg pains were initially reduced by >50%, with a slight deterioration over a 2-year period. Pain medication was reduced in 69% of the patients, and 89.7% of the patients were satisfied. CONCLUSION: Age itself cannot be considered a contraindication.

[Implantation of the ProDisc intervertebral disk prosthesis for the lumbar spine]. / Die Implantation der lumbalen Bandscheibenprothese vom Typ ProDisc.

OBJECTIVE: To eradicate treatment-resistant lower back pain caused by painful degeneration of the intervertebral disks. To avoid the disadvantages of alternative fusion surgery, especially degenerative wear and tear on adjacent segments, by maintaining the mobility of the affected motion segments. INDICATIONS: Treatment-resistant lower back pain due to painful degeneration of the intervertebral disks ("degenerative disk disease"). CONTRAINDICATIONS: Spondylolisthesis, scoliosis, osteoporosis, infection, spinal stenosis, degeneration of the vertebral articulations. SURGICAL TECHNIQUE: The intervertebral disk is excised through an anterior approach. It is essential to retain good mobility of the motion segment, if necessary, by resection of the posterior longitudinal ligament. After revitalization of the vertebral base and cover plates and chiseling of a groove for the keel of the prosthesis, the upper and lower prosthetic plates are inserted and the polyethylene inlay is locked into place. RESULTS: From April 2002 to May 2004, 36 ProDisc (Synthes Spine, West Chester, PA, USA) modular intervertebral disk prostheses were implanted in 34 patients (26 women, eight men, average age 44.3 years). Clinical evaluation was based on the visual analog scale (VAS), the Oswestry Disability Index (ODI), and the SF-36 Questionnaire. Follow-up assessment also included radiographic views of the lumbar spine in two planes in flexion and extension and standing. The follow-up interval for all patients was at least 1 year and 2 years for 14 patients. 26 patients were very satisfied with the operation, five patients were satisfied, and three patients were less satisfied. The clinical parameters recorded on the VAS, ODI and SF-36 improved from 7.4 to 2.8 (VAS), 48.0 to 13.1 (ODI) and 31.3 to 44.2 (SF-36, Physical Component Summary Score) from the time of the preoperative assessment to the 1-year follow-up. The range of motion at the segment with the implanted prosthesis was 10 degrees on average at L4/5 and 7 degrees on average at L5/S1 1 year postoperatively.

Is there an indication for prophylactic balloon kyphoplasty? A pilot study.

Vertebroplasty and kyphoplasty are associated with a recurrent fracture rate of 2.4% to 23%, which is lower than the general natural history of untreated osteoporotic fractures. Some authors suggest the risk of refracture at adjacent vertebra will be reduced by prophylactic stabilization. We therefore compared the refracture rate after prophylactic balloon kyphoplasty in 60 patients randomized into groups with either monosegmental balloon kyphoplasty or adjacent prophylactic balloon kyphoplasty. The level (superior versus inferior) for prophylactic stabilization was chosen according to fracture type. We evaluated patients for 12 months using radiographs, visual analog scale scores, and SF-36 scores. We followed 23 of 30 patients in the monosegmental group and 27 of 30 patients in the prophylactic group. We observed no difference in the 1-year refracture rates between the two groups (five patients in the monosegmental group and seven in the prophylactic group). Leakage into the disc was the presumed cause of adjacent fractures in 50% of the patients. Disc leakage and refracture rate did not correlate as a result of the low patient number. Based on our data, we believe there is no indication for prophylactic stabilization of adjacent segments with balloon kyphoplasty.

Preliminary results with modified techniques of balloon kyphoplasty for vertebra plana, traumatic fractures and neoplasms.

Percutaneous vertebroplasty and balloon kyphoplasty are less invasive treatment options than open surgery for patients with vertebral compression fractures. With balloon kyphoplasty, the injection of bone cement is preceded by inflation and removal of bone tamps (balloons) inside the fractured vertebral body. This allows for the creation of a void, where viscous cement is delivered resulting in a lower risk for cement leakage than with vertebroplasty. Another advantage of the balloon inflation is the potential to correct the deformity and restore sagittal alignment. The percutaneous techniques normally require intact pedicles and intact posterior elements. We found that modifying the technique made it suitable for the management of vertebra plana, traumatic fractures, and neoplasms. Our study documents the different modified techniques and the clinical results obtained within the first 21 patients.

No functional impairment after Robodoc total hip arthroplasty: gait analysis in 25 patients.

The Robodoc total hip replacement procedure requires a wider exposure of the proximal femur, especially of the greater trochanter, than the standard procedure. Moreover, the leg must be placed in a rigid leg-holder apparatus to obtain fixation in maximal hip adduction and external rotation. This may impair the hip abductors and reduce hip abduction in the mid- and terminal stance phase of the cycle. In this study we compared patients after Robodoc and conventional total hip arthroplasty with three-dimensional gait analysis (VICON System, Oxford Metrics, Oxford, U.K.) to assess the kinematics of the pelvis and hip. 25 patients underwent total hip replacement by means of the Robodoc total hip arthroplasty system, 25 patients were treated with conventional total hip replacement, and 40 healthy volunteers served as controls. None of the patients undergoing total hip replacement, robotic or conventional, obtained normal kinematic gait patterns 6 months after surgery. However, the reduction in hip abduction did not differ significantly in patients undergoing robotic or conventional total hip arthroplasty, which suggests that the robotic procedure did not impair hip abductor function more than the conventional method.

Patella resurfacing: no benefit for the long-term outcome of total knee arthroplasty. A 10- to 16.3-year follow-up.

A follow-up of more than 10 years among patients who have undergone a total knee arthroplasty (TKA) was performed to determine the significance of patella resurfacing for the long-term outcome. The clinical outcome was assessed by the Knee Society Score (KSS), and the radiological outcome was determined based on the Knee Society Roentgenographic Evaluation System. The patella was preserved in 21 knees and resurfaced in 44 knees. The mean follow-up time was 11.6 years (range 10-16.3 years). There was no significant difference in the clinical outcome between the knees with patella resurfacing (knee points: mean 85.3 +/-12.9, function points: mean 70.3 +/- 23.4) and the knees with patella retention (knee points: mean 82.7 +/- 16.2, function points: mean 71.7 +/- 22.4; p = 0.58 for knee, and p = 0.83 for function points). There was also no significant difference in the radiological outcomes regarding the angles alpha, beta, Upsilon, delta, and valgus ( p > 0.05 for each variable). There was, however, a trend towards more lucencies in TKAs with a resurfaced patella on the tibia side in the anteroposterior view ( p = 0.052). Patellar complications were found more often in the resurfaced group (20.5%) than in the group without resurfacing (9.6%). The results indicate overall no advantage of patella resurfacing compared with patella retention in the long run.

Scoring systems in total knee arthroplasty.

For assessment of total knee arthroplasty outcome, various scoring systems have been introduced. The current study assessed the interobserver correlation of four commonly used total knee arthroplasty outcome scores. One hundred eighteen total knee arthroplasties were investigated by two independent observers, using the Hungerford score, the Hospital for Special Surgery score, the Knee Society score, and the Bristol score. Each score consisted of three subscores: pain, knee, and function. For the highest interobserver correlation was computed for the Bristol score (interobserver correlation coefficient, 0.88). For knee range of motion, flexion contracture, and extension lag there was high interobserver correlation (interobserver correlation coefficient > 0.8 each). For walking distance and walking aids, there also was a high interobserver correlation (interobserver correlation coefficient > 0.7 each). For clinical assessment of total knee arthroplasty, pain should be measured on a four-step system, the knee should be assessed by measurement of range of motion, extension lag, and flexion contracture, and function should be measured on a separate score assessing walking distance and walking aids.

Interobserver and intraobserver reliability of Lenke's new scoliosis classification system.

STUDY DESIGN: The assignment of idiopathic scoliosis curves to the curve types,1-6 to the lumbar spine modifier (A, B, or C), and to the sagittal thoracic modifier (-, N, +), as recently described by Lenke et al, was evaluated by five observers on two occasions. OBJECTIVE: To determine the intraobserver and interobserver reliabilities of Lenke's new system for classifying idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: Lenke et al recently introduced a new system for classifying idiopathic scoliosis. METHODS: Preoperative standing long cassette coronal and sagittal radiographs as well as side-bending radiographs of 51 consecutive patients who underwent surgery for idiopathic scoliosis were labeled with the Cobb angles for all the curves. The center sacral vertical line was marked as the bisection of the proximal sacrum perpendicular to the true horizontal line. Five observers independently assigned a curve type, a lumbar spine modifier, and a sagittal thoracic modifier to each curve following the guidelines as described by Lenke et al. Assignment of the curves was repeated 3 weeks later, with the curves presented in a different order. Kappa coefficients were used to determine the interobserver and intraobserver reliabilities. RESULTS: All five reviewers agreed on the overall classification in 21 (41%) of the 51 patients. A mean kappa value of 0.62 was determined for interobserver reliability, and a mean kappa of 0.73 for intraobserver reliability. Determination of an upper thoracic curve as structural or nonstructural and assignment of a lumbar spine modifier were the main reasons for disagreement. CONCLUSIONS: Lenke's new classification system is more reliable than the older King classification, but proper classification of high thoracic and lumbar curves seems to be difficult.

Multisurgeon assessment of coronal pattern classification systems for adolescent idiopathic scoliosis: reliability and error analysis.

STUDY DESIGN: Three scoliosis surgeons and one orthopedic fellow were presented the anteroposterior radiographs of 70 patients with adolescent idiopathic scoliosis. All the reviewers assigned a type to each curve according to the classification systems of H. A. King and R. W. Coonrad. OBJECTIVES: To compare multisurgeon reliability in applying the classification systems of H. A. King and R. W. Coonrad, and to analyze controversially classified curve patterns. SUMMARY OF BACKGROUND DATA: The system most commonly used to classify adolescent idiopathic scoliosis is King's classification. However, because of poor interobserver reliability, the validity of this system is questioned. In contrast, high interobserver reliability is reported for Coonrad's classification system, which is used less frequently in clinical practice. METHODS: Interobserver agreement and intraobserver reproducibility were tested. Kappa coefficients were used to test reliability. Between the observers, the divergent assignments to curve patterns were analyzed in both quantitative and qualitative terms. An error analysis was performed. RESULTS: Paired comparisons showed a mean interobserver kappa coefficient of 0.45 for King's and 0.38 for Coonrad's classification systems. According to Svanholm et al, these values indicate poor reliability in terms of interobserver agreement. Error analyses for both classification systems showed that the reason for poor reproducibility is disagreement among the observers about structural upper thoracic and structural lumbar curves. CONCLUSIONS: Neither the King nor the Coonrad method appears to have sufficient interobserver reliability. To improve reliability, the authors recommend that the structural stigmas of the upper thoracic and lumbar curves be unequivocally described.

Intrapelvic complications after total hip arthroplasty failure.

BACKGROUND: Severe total hip arthroplasty failure with central migration of prosthetic components is uncommon. If perforation of the medial acetabular wall occurs, injuries of intrapelvic structures may result. DATA SOURCES: A meta-analysis of the English literature was performed. A human pelvic cadaver was used to demonstrate the proximity of intrapelvic structures to a centrally dislocated cup. RESULTS: Fifty cases of intrapelvic injury were identified. Structures involved most frequently were the external iliac artery and the bladder. The most common types of complication included fistula formation, development of a false aneurysm, and hemorrhage. The human cadaver pelvis demonstrated the proximity of intrapelvic vessels, the bladder, the ureter, the vagina, the deferent duct, the sigmoid colon, the rectum, and the sciatic nerve to an intrapelvically intruded prosthesis. CONCLUSIONS: Failed total hip replacements should be considered to cause damage to pelvic viscera.

Technical note: The quadrant technique for arthroscopic treatment of rotator cuff calcifications.

Reliable intraoperative localization of the calcium deposit is the most demanding and often time-consuming part of arthroscopic surgery for calcifying tendinitis of the rotator cuff. A new technique is described to intraoperatively localize calcium deposits based on preoperative ultrasonographic identification and subsequent assignment to a defined quadrant lateral of the acromion edge. The technique requires only a partial subacromial bursectomy, making the procedure less invasive and faster to perform.

Chronic low back pain measurement with visual analogue scales in different settings.

We asked 78 chronic low back pain patients to report on their usual pain intensity, and on the lifestyle changes caused by their pain, on a horizontally-oriented visual analogue scale (VAS). Also, the usual and the current pain intensities were examined on a vertical VAS. Statistical analysis showed normal distribution of data in the measurement of usual pain on the horizontal VAS, but no homogeneous distribution on the vertical VAS. Therefore, in the measurement of chronic low back pain VAS should be used horizontally rather than vertically, because of higher sensitivity. The intensity of usual pain was significantly correlated with the degree of lifestyle change. No correlation was found between current and usual pain. There was no significant difference in the failure rate between the vertical and horizontal VAS. Also, there was no reduction of the failure rate by giving additional oral explanations in the use of the scale to the patient. Owing to a negative influence in distribution of rates and an increase in the failure rate, complex questions should be avoided. A short written introduction to the scale is sufficient, and oral explanations are not essential.