Can quantitative sensory tests predict failed back surgery?: A prospective cohort study.

BACKGROUND: Failed back surgery syndrome (FBSS) is a pain condition refractory to therapy, and is characterised by persistent low back pain after spinal surgery. FBSS is associated with severe disability, low quality of life and high unemployment. We are currently unable to identify patients who are at risk of developing FBSS. Patients with chronic low back pain may display signs of central hypersensitivity as assessed by quantitative sensory tests (QST). This can contribute to the risk of developing persistent pain after surgery. OBJECTIVE: We tested the hypothesis that central hypersensitivity as assessed by QST predicts FBSS. DESIGN: Prospective cohort study. SETTING: Three tertiary care centres. PATIENTS: 141 patients scheduled for up to three segment spinal surgery for chronic low back pain (defined as at least 3 on a numerical rating scale on most days during the week and with a minimum duration of 3 months) due to degenerative changes. OUTCOMES: We defined FBSS as persistent pain, persistent disability or a composite outcome defined as either persistent pain or disability. The primary outcome was persistent pain 12 months after surgery. We applied 14 QST using electrical, pressure and temperature stimulation to predict FBSS and assessed the association of QST with FBSS in multivariable analyses adjusted for sociodemographic, psychological and clinical and surgery-related characteristics. RESULTS: None of the investigated 14 QST predicted FBSS, with 95% confidence intervals of crude and adjusted associations of all QST including one as a measure of no association. Results remained robust in all sensitivity and secondary analyses. CONCLUSION: The study indicates that assessment of altered central pain processing using current QST is unlikely to identify patients at risk of FBSS and is therefore unlikely to inform clinical decisions.

A rare case of non-traumatic, multi-level, bilateral pedicle fractures of the lumbar spine in a 60-year-old patient.

INTRODUCTION: We report a 60-year-old patient who sustained non-traumatic, multi-level, bilateral lumbar pedicle fractures in the setting of unilateral lumbar spondylolysis. A possible fracture mechanism is evaluated and a review of the literature is presented. Whereas contralateral pedicle fractures of lumbar vertebrae with unilateral spondylosis are well described in young athletes, there is only one case report of multi-level, bilateral pedicle fractures of the lumbar spine in a young patient who sustained a high-impact motorcycle accident. To our knowledge, this is the first report of multi-level, bilateral pedicular fractures of the lumbar spine without a history of trauma. METHODS: The clinical case of a 60-year-old patient with lumbar pain radiating in both legs without antecedent trauma is presented. Besides an idiopathic primary adrenal failure, no further co-morbidities existed. Radiologic investigations showed acute bilateral pedicles' fractures of the lumbar vertebrae two to four (L2-4) and a unilateral spondylolysis L4-5. Dorsoventral instrumentation from L1 to L5 was performed in two steps. RESULTS: The patient had no neurological deficits at discharge. Perioperative cortisol substitution was arranged and continued in the course. At final follow-up after 6 years the patient was pain-free and radiographs confirmed complete fusion of L1-5 with mild degeneration of the adjacent segments. CONCLUSION: The presented fracture pattern has not been described to date. Because of multi-level involvement, instability requiring operative stabilisation was presumed and confirmed during surgery.

Temporary liver and stomach necrosis after lateral approach for interbody fusion and deformity correction of lumbar spine: report of two cases and review of the literature.

INTRODUCTION: Corrections of spinal deformities have been associated with a potential of postoperative vessel-originating complications. Reports of occlusions of celiac artery seem though to be very rare. CASE REPORTS: We present two cases that developed acute arterial supply impairment and subsequent liver and gastric necrosis due to an occlusion of celiac artery, after a spine deformity correction. In both patients a lateral surgical approach to the superior lumbar spine, lateral placement of cages and then a subsequent posterior fixation were performed. REVIEW: The literature search reveals the report of three similar cases, with potentially different pathogenetic mechanisms and with a different prognosis. This complication is assumed to occur due to a Medial Arcuate Ligament syndrome (MALS) developed postoperatively that leaded to compression of the celiac artery against the Medial Arcuate Ligament. The pathogenesis though remains unclear and two theories are assumed to explain the acute appearance of the syndrome; the alteration of the anatomic relationship between the vessels and the surrounding tissues due to the spine deformity correction and an intraoperative direct or indirect traction injury of the celiac trunk that caused or increased its pressure against the medial arcuate ligament. CONCLUSION: The spine surgeon should be aware of the possibility of postoperative ischemia of the liver and stomach by occlusion of the celiac artery or its supplying branches. Specifically when a large correction of a kyphotic/kyphoscoliotic spine is planed, the surgeon should be alert for an appearance of a MALS.

No kidding: low back pain and type of container influence adolescents' perception of load heaviness.

PURPOSE: The relationship between low back pain (LBP) and the lifting/carrying of loads is still a matter of great discussion. In teenagers, the weight of the school bag has been considered to play a pathogenic role in LBP but the relationship between the actual weight of the school bag and LBP symptoms does not seem to be a straightforward one. Numerous factors have been identified that influence the perception of weight. This study aimed to evaluate the influence of low back pain and the type of container on the perception of load heaviness by healthy teenagers. METHODS: A convenience sample of 80 healthy teenage males (mean ± SD age 13.9 ± 2.1 years) was recruited from the members of two local sports clubs. The volunteers were evaluated during one of their training sessions. Information about a history of consequential LBP was gathered by questionnaire. Subjects were invited to estimate the weight of three bags (a typical school bag, a sports bag with the logo of a well-known brand, and a neutral bag) containing two different loads (total weights approximately 3 and 5 kg). RESULTS: Consequential LBP (i.e., LBP requiring medical attention and/or interfering with usual sports activities) was reported by 26.2% of them. The majority of the LBP episodes occurred ≥3 months before the tests. Overall, teenagers significantly (p ≤ 0.05) underestimated the weight of the sports bag compared with the school bag and the neutral bag. Compared with those with no LBP, subjects with a history of LBP overestimated the weight of the heavier load. CONCLUSIONS: Our results suggest that several subjective variables significantly influence the perception of load heaviness. Until we have a better understanding of the mechanical role of the backpack weight versus the perception of its weight in the aetiology of LBP, any recommendations about the schoolbag weight limit should be viewed with caution.

Five-year results of lumbar disc prostheses in the SWISSspine registry.

PURPOSE: The Swiss Federal Office of Public Health demanded a nationwide HTA registry for lumbar total disc arthroplasty (TDA), to decide about its reimbursement. The goal of the SWISS spine registry is to generate evidence about the safety and efficiency of lumbar TDA. METHODS: Two hundred forty-eight cases treated between 3-2005 and 6-2006, who were eligible for the 5-year follow-up were included in the study. Follow-up rates for 3-6 months, 1, 2 and 5 years were 85.9, 77.0, 44.0 and 51.2 %, respectively. Outcome measures were back and leg pain, medication consumption, quality of life, intraoperative and postoperative complication and revision rates. Additionally, segmental mobility, ossification, adjacent and distant segment degeneration were analysed at the 5-year follow-up. RESULTS: There was a significant, clinically relevant and lasting reduction of back (preop/postop 73/29 VAS points) and leg pain (preop/postop VAS 55/22) and a consequently decreased analgesics consumption and quality of life improvement (preop/postop 0.30/0.76 EQ-5D score points) until 5 years after surgery. The rates for intraoperative and early postoperative complications were 4.4 and 3.2 %, respectively. The overall complication rate during five postoperative years was 23.4 %, and the adjacent segment degeneration rate was 10.7 %. In 4.4 % of patients, a revision surgery was performed. Cumulative survivorship probability for a revision/re-intervention-free 5-year postoperative course was 90.4 %. At the 5-year follow-up, the average range of motion of the mobile segments (86.8 %) was 9.7°. In 43.9 % of patients, osteophytes at least potentially affecting the range of motion were seen. CONCLUSIONS: Lumbar TDA appeared as efficient in long-term pain alleviation, consequent reduction of pain medication consumption and improvement of quality of life. The procedure also appeared sufficiently safe, but surgeons have to be aware of a list of potential adverse events. The outcome is stable over the 5-year postoperative period. The vast majority of treated segments remained mobile after 5 years, although almost half of patients showed osteophytes.

Transiliac-Transsacral Screw Fixation is Superior to Lumbopelvic Stabilization in the Treatment of Minimally Displaced Sacral H-/U-Type Fragility Fractures.

STUDY DESIGN: Retrospective Cohort Study. OBJECTIVES: To compare the outcomes and complications of transiliac-transsacral screw fixation (TIS) and lumbopelvic fixation (LPS), the 2 most common fixation methods for nondisplaced and minimally displaced H-/U- type sacral fragility fractures. METHODS: Medical records of patients treated with TIS or LPS for nondisplaced and minimally displaced H-/U-type sacral fragility fractures at 2 level A trauma centers between 2012 and 2022 were analyzed. Postoperative low back pain and mobility levels were assessed as primary outcomes before discharge and at 6 weeks and 6 months postoperatively. Surgery time, blood loss, and surgical complication rates were assessed as secondary outcomes. Statistical analyses consisted of Fisher's exact tests for frequency distributions and Mann-Whitney-U tests and t-tests for group comparisons. RESULTS: 52 patients undergoing TIS (mean age: 78 ± 9 years) and 36 patients undergoing LPS (74 ± 10 years) with no discrepancy in demographic parameters were identified. There were no differences in low back pain levels between the 2 groups before surgery, before discharge, at 6 weeks postoperatively, and at 6 months postoperatively (P > 0.05). There were no differences in mobility levels before surgery, before discharge, at 6 weeks postoperatively, and at 6 months postoperatively (P > 0.05). Duration of surgery was shorter after TIS (36 ± 13 min) compared to LPS (113 ± 31 min) (P < 0.0001). Intraoperative blood loss was lower for TIS (median <20 mL) compared to LPS (median 125 mL) (P < 0.0001). Postoperative radiculopathy was less frequent after TIS (n = 1) compared to LPS (n = 3) (P > 0.05). Median length of stay was shorter after TIS (11 days) compared to LPS (14 days) (P < 0.05). Rates of reoperations directly related to the index surgery were lower after TIS (n = 2) compared to LPS (n = 10) (P < 0.01). Implant failures were observed only after LPS (n = 1). CONCLUSION: Patients with nondisplaced and minimally displaced H-/U- type sacral fragility fractures may preferably be treated using TIS, as it is equivalent to LPS in terms of low back pain reduction and restoration of mobility, but allows for shorter operative time, less blood loss and lower reoperation rates. Prospective randomized studies should be conducted to substantiate our findings and develop distinct treatment recommendations.

Long-term follow-up after vertebroplasty - A mean 10-years follow-up control study.

Objectives: To evaluate the clinical 10 year outcome of patients treated with percutaneous vertebroplasty for vertebral compression fractures and to determine the incidence of new fractures in this time interval, as well as the mortality of the patients who underwent this procedure. Methods: All patients undergoing vertebroplasty for vertebral compression fractures between May 2007 until July 2008 were prospectively followed up at 10 years postoperatively. Patients were assessed for radiologic outcome and self-reported outcome parameters (PROs). Gathered parameters remained unmodified to the initial ones analyzing QoL improvement (EQ5D 3L and NASS score) and pain alleviation (VAS, NRS). Mortality was defined as an additional endpoint. Exclusion criteria include additional instrumentation, use of additional devices such as kyphoplasty balloons/stentoplasty, cognitive impairment, insufficient radiological documentation or absent re-consent. Results: Of 280 patients who underwent vertebroplasty, 49 (17.5%) were available for re-assessment with a mean follow-up of 10.5 years (9.9-11.1). Thirty patients (10.7%) were assessed clinically and radiologically, 16 (5.7%) in written form and three (1.1%) by phone only. A total of 186 (66.4%) died during the follow up period. Out of the remaining 45 patients, 27 patients declined participation, eight couldn't participate due to cognitive impairment, four had insufficient radiologic documentation. Six patients were lost to follow-up. At 10 years, patients reported a consistently improved quality of life (EQ-5D; p < 0.01) and global satisfaction. Vertebroplasty demonstrated a substantial and enduring effect on alleviating back pain over 10 years (p < 0.001). 26 (53%) patients experienced a new fracture since the initial procedure. Conclusion: A decade following vertebroplasty, patients continue to demonstrate a quality of life and pain level comparable to short and medium-term assessments, with a significant difference from baseline measurements. More than half (53%) of the patients participating at last follow-up experienced new fractures during this interim period. The cohort as a whole has been impacted by an elevated mortality rate over the time period.

Radiographic and safety details of vertebral body stenting: results from a multicenter chart review.

BACKGROUND: Up to one third of BKP treated cases shows no appreciable height restoration due to loss of both restored height and kyphotic realignment after balloon deflation. This shortcoming has called for an improved method that maintains the height and realignment reached by the fully inflated balloon until stabilization of the vertebral body by PMMA-based cementation. Restoration of the physiological vertebral body height for pain relief and for preventing further fractures of adjacent and distant vertebral bodies must be the main aim for such a method. A new vertebral body stenting system (VBS) stabilizes the vertebral body after balloon deflation until cementation. The radiographic and safety results of the first 100 cases where VBS was applied are presented. METHODS: During the planning phase of an ongoing international multicenter RCT, radiographic, procedural and followup details were retrospectively transcribed from charts and xrays for developing and testing the case report forms. Radiographs were centrally assessed at the institution of the first/senior author. RESULTS: 100 patients (62 with osteoporosis) with a total of 103 fractured vertebral bodies were treated with the VBS system. 49 were females with a mean age of 73.2 years; males were 66.7 years old. The mean preoperative anterior-middle-posterior heights were 20.3-17.6-28.0 mm, respectively. The mean local kyphotic angle was 13.1°. The mean preoperative Beck Index (anterior edge height/posterior edge height) was 0.73, the mean alternative Beck Index (middle height/posterior edge height) was 0.63. The mean postoperative heights were restored to 24.5-24.6-30.4 mm, respectively. The mean local kyphotic angle was reduced to 8.9°. The mean postoperative Beck Index was 0.81, the mean alternative one was 0.82. The overall extrusion rate was 29.1%, the symptomatic one was 1%. In the osteoporosis subgroup there were 23.8% extrusions. Within the three months followup interval there were 9% of adjacent and 4% of remote new fractures, all in the osteoporotic group. CONCLUSIONS: VBS showed its strengths especially in realignment of crush and biconcave fractures. Given that fracture mobility is present, the realignment potential is sound and increases with the severity of preoperative vertebral body deformation.

Minimal-invasive percutaneous reduction and transsacral screw fixation for U-shaped fractures.

STUDY DESIGN: Technical note and case series. OBJECTIVE: To introduce an innovative minimal-invasive surgical procedure reducing surgery time and blood loss in management of U-shaped sacrum fractures. SUMMARY OF BACKGROUND: Despite their seldom appearance, U-shaped fractures can cause severe neurological deficits and surgical management difficulties. According to the nature of the injury normally occurring in multi-injured patients after a fall from height, a jump, or road traffic accident, U-shaped fractures create a spinopelvic dissociation and hence are highly unstable. In the past, time-consuming open procedures like large posterior constructs or shortening osteotomies with or without decompression were the method of choice, sacrificing spinal mobility. Insufficient restoration of sacrococcygeal angle and pelvic incidence with conventional techniques may have adverse long-term effects in these patients. METHODS: In a consecutive series of 3 patients, percutaneous reduction of the fracture with Schanz pins inserted in either the pedicles of L5 or the S1 body and the posterior superior iliac crest was achieved. The Schanz pins act as lever, allowing a good manipulation of the fracture. The reduction is secured by a temporary external fixator to permit optimal restoration of pelvic incidence and sacral kyphosis. Insertion of 2 transsacral screws allow fixation of the restored spinopelvic alignment. RESULTS: Anatomic alignment of the sacrum was possible in each case. Surgery time ranged from 90 to 155 minutes and the blood loss was <50 mL in all 3 cases. Two patients had very good results in the long term regarding maintenance of pelvic incidence and sacrococcygeal angle. One patient with previous cauda equina decompression had loss of correction after 6 months. CONCLUSIONS: Percutaneous reduction and transsacral screw fixation offers a less invasive method for treating U-shaped fractures. This can be advantageous in treatment of patients with multiple injuries.

Are there cervical spine findings at MR imaging that are specific to acute symptomatic whiplash injury? A prospective controlled study with four experienced blinded readers.

PURPOSE: To compare the magnetic resonance (MR) imaging findings in patients with acute whiplash injury with those in matched control subjects. MATERIALS AND METHODS: In a prospective multicenter controlled study, from 2005 to 2008, 100 consecutive patients underwent 1.5-T MR imaging examinations of the cervical spine within 48 hours after a motor vehicle accident. Findings in these patients were compared in a blinded fashion with those in 100 age- and sex-matched healthy control subjects. Four blinded independent readers assessed the presence of occult vertebral body and facet fractures, vertebral body and facet contusions, intervertebral disk herniations, ligamentum nuchae strains, ligamentum nuchae tears, muscle strains or tears, and perimuscular fluid. Accuracy (as compared with clinical findings) and interobserver reliability were calculated. RESULTS: Accuracy of MR imaging and interreader reliability were generally poor (sensitivity, 0.328; specificity, 0.728; positive and negative likelihood ratios, 1.283 and 1.084, respectively). MR imaging findings significantly associated with whiplash injuries were occult fracture (P<.01), bone marrow contusion of the vertebral body (P=.01), muscle strain (P<.01) or tear (P<.01), and the presence of perimuscular fluid (P<.01). While 10 findings thought to be specific for whiplash trauma were significantly (P<.01) more frequent in patients (507 observations), they were also regularly found in healthy control subjects (237 observations). There were no serious occult injuries that required immediate therapy. CONCLUSION: MR imaging at 1.5 T reveals only limited evidence of specific changes to the cervical spine and the surrounding tissues in patients with acute symptomatic whiplash injury compared with healthy control subjects.

Cervical spine injury in the young child.

This grand rounds is about the clinical and radiological presentation, treatment and outcome of pediatric cervical spine injury. A 15-month-old girl suffers from a motor vehicle accident and is intubated on-site because of progressive agitation. Whole body trauma CT was read as normal. When sedation was discontinued after 24 h she was found to be tetraplegic below C6 level. MRI shows a total disruption between C6 and C7 that in hindsight was also visible on the initial trauma CT. She was treated surgically by an anterior and posterior reconstruction and was post-operatively treated with a halo vest. Clearing the cervical spine in young children is deceptively difficult. Meticulous review and interpretation of conventional radiographs and CT are important yet MRI should be considered in uncertain cases. Severe ligamentous injury without concomitant bony injury occurs more frequently than in older children and adults, with sometimes devastating consequences.

Safety, effectiveness and predictors for early reoperation in therapeutic and prophylactic vertebroplasty: short-term results of a prospective case series of patients with osteoporotic vertebral fractures.

INTRODUCTION: Vertebroplasty (VP) is a cost-efficient alternative to kyphoplasty; however, regarding safety and vertebral body (VB) height restoration, it is considered inferior. We assessed the safety and efficacy of VP in alleviating pain, improving quality of life (QoL) and restoring alignment. METHODS: In a prospective monocenter case series from May 2007 until July 2008, there were 1,408 vertebroplasties performed during 319 interventions in 306 patients with traumatic, lytic and osteoporotic fractures. The 249 interventions in 233 patients performed because of osteoporotic vertebral fractures were analyzed regarding demographics, treatment and radiographic details, pain alleviation (VAS), QoL improvement (NASS and EQ-5D), complications and predictors for new fractures requiring a reoperation. RESULTS: The osteoporotic patient sample consisted of 76.7% (179) females with a median age of 80 years. A total of 54 males had a median age of 77 years. On average, there were 1.8 VBs fractured and 5 VBs treated. The preoperative pain was assessed by the visual analog scale (VAS) and decreased from 54.9 to 40.4 pts after 2 months and 31.2 pts after 6 months. Accordingly, the QoL on the EQ-5D measure (-0.6 to 1) improved from 0.35 pts before surgery to 0.56 pts after 2 and to 0.68 pts after 6 months. The preoperative Beck Index (anterior height/posterior height) improved from a mean of 0.64 preoperative to 0.76 postoperative, remained stable at 2 months and slightly deteriorated to 0.72 at 6 months postoperatively. There were cement leakages in 26% of the fractured VBs and in 1.4% of the prophylactically cemented VBs; there were symptoms in 4.3%, and most of them were temporary hypotension and one pulmonary cement embolism that remained asymptomatic. The univariate regression model revealed a tendency for a reduced risk for new or refractures on radiographs (OR = 2.61, 95% CI 0.92-7.38, p = 0.12) and reoperations (OR = 2.9, 95% CI 0.94-8.949, p = 0.1) when prophylactic augmentation was performed. The final multivariate regression model revealed male patients to have an about three times higher refracture risk (radiographic) (OR = 2.78, p = 0.02) at 6 months after surgery. Patients with a lumbar index fracture had an about three to five times higher refracture/reoperation risk than patients with a thoracic (OR = 0.33/0.35, p = 0.009/0.01) or thoracolumbar (OR = 0.32/0.22, p = 0.099/0.01) index fracture. CONCLUSION: If routinely used, VP is a safe and efficacious treatment option for osteoporotic vertebral fractures with regard to pain relief and improvement of the QoL. Even segmental realignment can be partially achieved with proper patient positioning. Certain patient or fracture characteristics increase the risk for early radiographic refractures or new fractures, or a reoperation; a consequent prophylactic augmentation showed protective tendencies, but the study was underpowered for a final conclusion.

Complications related to cement leakage in sacroplasty.

Data concerning the safety of sacroplasty in terms of cement leakage is scarce. Frequency, distribution patterns and clinical consequences of cement leakage were assessed in 33 patients (28 female, mean age: 74 +/- 10 yrs; bilateral SIF: n = 30, 63 sacroplasties) treated with sacroplasty between 06/2003 and 11/2010 in a retrospective study using patients' records, operative notes and postoperative radiographs. Cement leakage was noted within the fracture gap (27%), into veins (6%), neuroforamina (3%) or in the intervertebral disc space L5/S1 (2%). In one patient, cement leakage into the fracture gap led to unilateral radiculopathy of the 5th lumbar nerve root. Leakage into the fracture gap is at high risk of affecting the 5th lumbar nerve root due to the special course of its ventral branch over the sacral promontory. The risks of cement leakage with neurological impairment should be explained to patients.

PMMA-Cement-PLIF Is Safe and Effective as a Single-Stage Posterior Procedure in Treating Pyogenic Erosive Lumbar Spondylodiscitis-A Single-Center Retrospective Study of 73 Cases.

BACKGROUND: Surgical treatment for erosive pyogenic spondylodiscitis of the lumbar spine is challenging as, following debridement of the intervertebral and bony abscess, a large and irregular defect is created. Sufficient defect reconstruction with conventional implants using a posterior approach is often impossible. Therefore, we developed the "Cement-PLIF", a single-stage posterior lumbar procedure, combining posterior lumbar interbody fusion (PLIF) with defect-filling using antibiotic-loaded polymethylmethacrylate (PMMA). This study first describes and evaluates the procedure's efficacy, safety, and infection eradication rate. Radiological implant stability, bone-regeneration, sagittal profile reconstruction, procedure-related complications, and pre-existing comorbidities were further analyzed. METHODS: A retrospective cohort study analyzing 73 consecutive patients with a minimum of a one-year follow-up from 2000-2017. Patient-reported pain levels and improvement in infectious serological parameters evaluated the clinical outcome. Sagittal profile reconstruction, anterior bone-regeneration, and posterior fusion were analyzed in a.p. and lateral radiographs. A Kaplan-Meier analysis was used to determine the impact of pre-existing comorbidities on mortality. Pre-existing comorbidities were quantified using the Charlson-Comorbidity Index (CCI). RESULTS: Mean follow-up was 3.3 (range: 1-16; ±3.2) years. There was no evidence of infection persistence in all patients at the one-year follow-up. One patient underwent revision surgery for early local infection recurrence (1.4%). Five (6.9%) patients required an early secondary intervention at the same level due to minor complications. Radiological follow-up revealed implant stability in 70/73 (95.9%) cases. Successful sagittal reconstruction was demonstrated in all patients (p < 0.001). There was a significant correlation between Kaplan-Meier survival and the number of pre-existing comorbidities (24-months-survival: CCI ≤ 3: 100%; CCI ≥ 3: 84.6%; p = 0.005). CONCLUSIONS: The Cement-PLIF procedure for pyogenic erosive spondylodiscitis is an effective and safe treatment as evaluated by infection elimination, clinical outcome, restoration, and maintenance of stability and sagittal alignment.

Cervical muscle area measurements in acute whiplash patients and controls.

PURPOSE: To quantitatively compare the muscle cross-sectional areas (CSAs) of the cervical muscles in symptomatic acute whiplash patients versus healthy controls. We hypothesized, that symptomatic whiplash patients have smaller cervical muscle CSAs than matched controls and that smaller cervical muscle CSAs in women might explain that women more frequently are symptomatic after whiplash injury than men. MATERIALS AND METHODS: Prospective controlled study. Thirty-eight consecutive acute whiplash patients were examined within 48 h after a motor vehicle accident and 38 healthy age- and sex-matched controls, each half female, half male, were examined with the same protocol. MRI CSA measurements were performed of the deep and total cervical extensor muscles as well as the sternocleidomastoid muscles using transversal STIR (Short T1 Inversion Recovery) sequences on level C2, C4, and C5 by two blinded raters. Clinical symptoms were assessed with patient questionnaires (EuroQuol 5D, Specific Whiplash Questionnaire, head- and neck pain intensity [VAS]). RESULTS: Agreement of measurements between the two raters was high (intraclass correlation 0.52 to 0.85 for the different levels). No significant difference in age and body mass index were seen between patients and controls and the distribution of genders across groups was identical. There were no significant differences between patients and controls for all CSAs. Women had consistently smaller CSAs than men. The CSAs showed no significant correlation with the pain intensity of neck pain and headache but a consistent tendency of less neck pain and more headache with greater CSAs. CONCLUSION: This small study provides no evidence that subjects with smaller CSAs of cervical extensor muscles have a higher risk in developing symptoms after a whiplash injury and confirms smaller CSA in women.

Expert's comment concerning grand rounds case entitled "a traumatic, high-energy and unstable fracture of the C5 vertebra managed with kyphoplasty: a previously unreported case" (by Nasir A. Quraishi and Sherief Elsayed).

Case presentation of a cervical spine fracture treated by kyphoplasty. The review of the case, especially the careful re-assessment of the x-rays reveals that the treatment goals have not been achieved (motion preservation, functional restoration of the vertebral body). The case report is an excellent example of our biased viewpoint in assessing our efforts.

Cold pain hypersensitivity predicts trajectories of pain and disability after low back surgery: a prospective cohort study.

Improving the ability to predict persistent pain after spine surgery would allow identification of patients at risk and guide treatment decisions. Quantitative sensory tests (QST) are measures of altered pain processes, but in our previous study, preoperative QST did not predict pain and disability at single time-points. Trajectory analysis accounts for time-dependent patterns. We hypothesized that QST predict trajectories of pain and disability during 1 year after low back surgery. We performed a trajectory analysis on the cohort of our previous study (n = 141). Baseline QST included electrical, pressure, heat, and cold stimulation of the low back and lower extremity, temporal summation, and conditioned pain modulation. Pain intensity and Oswestry Disability Index were measured before, and 2, 6, and 12 months after surgery. Bivariate trajectories for pain and disability were computed using group-based trajectory models. Multivariable regressions were used to identify QST as predictors of trajectory groups, with sociodemographic, psychological, and clinical characteristics as covariates. Cold pain hypersensitivity at the leg, not being married, and long pain duration independently predicted worse recovery (complete-to-incomplete, incomplete-to-no recovery). Cold pain hypersensitivity increased the odds for worse recovery by 3.8 (95% confidence intervals 1.8-8.0, P < 0.001) and 3.0 (1.3-7.0, P = 0.012) in the univariable and multivariable analyses, respectively. Trajectory analysis, but not analysis at single time-points, identified cold pain hypersensitivity as strong predictor of worse recovery, supporting altered pain processes as predisposing factor for persisting pain and disability, and a broader use of trajectory analysis. Assessment of cold pain sensitivity may be a clinically applicable, prognostic test.

Hierarchical clustering of flow cytometry data for the study of conventional central chondrosarcoma.

We have investigated the use of hierarchical clustering of flow cytometry data to classify samples of conventional central chondrosarcoma, a malignant cartilage forming tumor of uncertain cellular origin, according to similarities with surface marker profiles of several known cell types. Human primary chondrosarcoma cells, articular chondrocytes, mesenchymal stem cells, fibroblasts, and a panel of tumor cell lines from chondrocytic or epithelial origin were clustered based on the expression profile of eleven surface markers. For clustering, eight hierarchical clustering algorithms, three distance metrics, as well as several approaches for data preprocessing, including multivariate outlier detection, logarithmic transformation, and z-score normalization, were systematically evaluated. By selecting clustering approaches shown to give reproducible results for cluster recovery of known cell types, primary conventional central chondrosacoma cells could be grouped in two main clusters with distinctive marker expression signatures: one group clustering together with mesenchymal stem cells (CD49b-high/CD10-low/CD221-high) and a second group clustering close to fibroblasts (CD49b-low/CD10-high/CD221-low). Hierarchical clustering also revealed substantial differences between primary conventional central chondrosarcoma cells and established chondrosarcoma cell lines, with the latter not only segregating apart from primary tumor cells and normal tissue cells, but clustering together with cell lines from epithelial lineage. Our study provides a foundation for the use of hierarchical clustering applied to flow cytometry data as a powerful tool to classify samples according to marker expression patterns, which could lead to uncover new cancer subtypes.

The role of central hypersensitivity in the determination of intradiscal mechanical hyperalgesia in discogenic pain.

OBJECTIVE: The primary aim of the present study was to investigate whether there is a relationship between central hypersensitivity (assessed by pressure pain thresholds of uninjured tissues) and intradiscal pain threshold during discography. The secondary aim was to test the hypothesis that peripheral noxious stimulation dynamically modulates central hypersensitivity. PATIENTS: Twenty-four patients with positive provocation discography were tested for central hypersensitivity by pressure algometry before and after the intervention with assessments of pressure pain detection and tolerance thresholds. Intradiscal pain threshold was assessed by measuring intradiscal pressure at the moment of pain provocation during discography. Correlation analyses between intradiscal pain threshold and pressure algometry were made. For the secondary aim, pressure algometry data before and after discography were compared. RESULTS: Significant correlation with intradiscal pain threshold was found for pressure pain detection threshold at the toe (regression coefficient: 0.03, P = 0.05) and pressure pain tolerance thresholds at the nonpainful point at the back (0.02, P = 0.024). Tolerance threshold at the toe was a significant predictor for intradiscal pain threshold only in multiple linear regression (0.036, P = 0.027). Detection as well as tolerance thresholds significantly decreased after discography at the painful and the nonpainful point at the back, but not at the toe. CONCLUSIONS: Central hypersensitivity may influence intradiscal pain threshold, but with a modest quantitative impact. The diagnostic value of provocation discography is therefore not substantially impaired. Regional, but not generalized central hypersensitivity is dynamically modulated by ongoing peripheral nociceptive input.