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1.
Eur Spine J ; 26(10): 2573-2580, 2017 10.
Article in English | MEDLINE | ID: mdl-28161752

ABSTRACT

PURPOSE: The nerve root sedimentation sign (SedSign) is a magnetic resonance imaging (MRI) sign for the diagnosis of lumbar spinal stenosis (LSS). It is included in the assessment of LSS to help determine whether decompression surgery is indicated. Assessment of the reversibility of the SedSign after surgery may also have clinical implications for the decision about whether or not a secondary operation or revision is needed. This study investigated if lumbar decompression leads to a reversal of the SedSign in patients with LSS and a positive SedSign pre-operatively; and if a reversal is associated with more favourable clinical outcomes. If reversal of the SedSign is usual after sufficient decompression surgery, a new positive SedSign could be used as an indicator of new stenosis in previously operated patients. METHODS: A prospective cohort study of 30 LSS patients with a positive pre-operative SedSign undergoing decompression surgery with or without instrumented fusion was undertaken to assess the presence of nerve root sedimentation (=negative SedSign) on MRI at 3 months post-operation. Functional limitation (Oswestry Disability Index, ODI), back and leg pain (Visual Analogue Scale, VAS), and treadmill walking distance were also compared pre- and 3 months post-operatively. The short follow-up period was chosen to exclude adjacent segment disease and the potential influence of surgical technique on clinical outcomes at longer follow-up times. RESULTS: 30 patients [median age 73 years (interquartile range (IQR) 65-79), 16 males] showed a median pre-operative ODI of 66 (IQR 52-78), a median VAS of 8 (IQR 7-9), and a median walking distance of 0 m (IQR 0-100). Three months post-operation 27 patients had a negative SedSign. In this group, we found improved clinical outcomes at follow-up: median post-operative ODI of 21 (IQR 12-26), median VAS of 2 (IQR 2-4), and median walking distance of 1000 m (IQR 500-1000). These changes were all statistically significant (p < 0.001). Three patients had a positive SedSign at 3-month follow-up due to epidural fat (n = 2) or a dural cyst following an intra-operative dural tear (n = 1), but also showed improvements in clinical outcomes for ODI, VAS and walking distance. CONCLUSION: The reversibility of a pre-operative positive SedSign was demonstrated after decompression of the affected segmental level and associated with an improved clinical outcome. A persisting positive SedSign could be the result of incomplete decompression or surgical complications. A new positive SedSign after sufficient decompression surgery could be used as an indicator of new stenosis in previously operated patients.


Subject(s)
Decompression, Surgical , Lumbar Vertebrae/diagnostic imaging , Magnetic Resonance Imaging , Spinal Nerve Roots/diagnostic imaging , Spinal Stenosis/diagnostic imaging , Spinal Stenosis/surgery , Aged , Cohort Studies , Disability Evaluation , Female , Follow-Up Studies , Humans , Lumbar Vertebrae/surgery , Male , Middle Aged , Visual Analog Scale
3.
Spine (Phila Pa 1976) ; 41(15): 1239-1246, 2016 Aug 01.
Article in English | MEDLINE | ID: mdl-26839989

ABSTRACT

STUDY DESIGN: Delphi. OBJECTIVE: The aim of this study was to obtain an expert consensus on which history factors are most important in the clinical diagnosis of lumbar spinal stenosis (LSS). SUMMARY OF BACKGROUND DATA: LSS is a poorly defined clinical syndrome. Criteria for defining LSS are needed and should be informed by the experience of expert clinicians. METHODS: Phase 1 (Delphi Items): 20 members of the International Taskforce on the Diagnosis and Management of LSS confirmed a list of 14 history items. An online survey was developed that permits specialists to express the logical order in which they consider the items, and the level of certainty ascertained from the questions. Phase 2 (Delphi Study) Round 1: Survey distributed to members of the International Society for the Study of the Lumbar Spine. Round 2: Meeting of 9 members of Taskforce where consensus was reached on a final list of 10 items. Round 3: Final survey was distributed internationally. Phase 3: Final Taskforce consensus meeting. RESULTS: A total of 279 clinicians from 29 different countries, with a mean of 19 (±SD: 12) years in practice participated. The six top items were "leg or buttock pain while walking," "flex forward to relieve symptoms," "feel relief when using a shopping cart or bicycle," "motor or sensory disturbance while walking," "normal and symmetric foot pulses," "lower extremity weakness," and "low back pain." Significant change in certainty ceased after six questions at 80% (P < .05). CONCLUSION: This is the first study to reach an international consensus on the clinical diagnosis of LSS, and suggests that within six questions clinicians are 80% certain of diagnosis. We propose a consensus-based set of "seven history items" that can act as a pragmatic criterion for defining LSS in both clinical and research settings, which in the long term may lead to more cost-effective treatment, improved health care utilization, and enhanced patient outcomes. LEVEL OF EVIDENCE: 2.


Subject(s)
Lumbar Vertebrae/surgery , Spinal Stenosis/diagnosis , Awards and Prizes , Consensus , Delphi Technique , Humans , Low Back Pain/diagnosis , Low Back Pain/physiopathology , Nervous System Diseases/diagnosis , Spinal Stenosis/therapy , Surveys and Questionnaires
4.
Spine (Phila Pa 1976) ; 40(3): 129-36, 2015 Feb 01.
Article in English | MEDLINE | ID: mdl-25668333

ABSTRACT

STUDY DESIGN: Subgroup analysis of the lumbar spinal stenosis (LSS) without degenerative spondylolisthesis diagnostic cohort of the Spine Patient Outcomes Research Trial multicenter randomized clinical trial with a concurrent observational cohort. OBJECTIVE: To determine if sedimentation sign on magnetic resonance image can help with LSS treatment decisions. SUMMARY OF BACKGROUND DATA: LSS is one of the most common reasons for surgery in the US elderly, but there is a dearth of reliable diagnostic tools that give a clear indication for surgery. Recent studies have suggested that positive sedimentation sign on magnetic resonance image may be a possible prognostic indicator. METHODS: All patients with LSS in both the randomized and observational cohorts had imaging-confirmed stenosis, were surgical candidates, and had neurogenic claudication for at least 12 weeks prior to enrollment. Patients were categorized as "mild," "moderate," or "severe" according to stenosis severity. Of the 654 patients with LSS enrolled in Spine Patient Outcomes Research Trial, complete T2-weighted axial and sagittal digitized images of 115 patients were available for retrospective review. An independent orthopedic spine surgeon evaluated these deidentified Digital Imaging and Communications in Medicine files for the sedimentation sign. RESULTS: Sixty-six percent (76/115) of patients were found to have a positive sedimentation sign. Those with a positive sedimentation sign were more likely to have stenosis at L2-L3 (33% vs. 10% P=0.016) or L3-L4 76% vs. 51%, P=0.012), and to have severe (72% vs. 33%, P<0.0001) central stenosis (93% vs. 67% P<0.001) at 2 or more concurrent levels (57% vs. 18%, P=0.01). In multivariate models, the surgical treatment effect was significantly larger in the positive sedimentation sign group for Oswestry Disability Index (-16 vs. -7; P=0.02). CONCLUSION: A positive sedimentation sign was associated with a small but significantly greater surgical treatment effect for Oswestry Disability Index in patients with symptomatic LSS, after adjusting for other demographic and imaging features. These findings suggest that positive sedimentation sign may potentially be a useful adjunct to help guide an informed treatment choice regarding surgery for LSS. LEVEL OF EVIDENCE: 2.


Subject(s)
Lumbar Vertebrae/pathology , Magnetic Resonance Imaging , Spinal Stenosis/pathology , Aged , Clinical Decision-Making , Decompression, Surgical , Female , Humans , Image Processing, Computer-Assisted , Lumbar Vertebrae/surgery , Male , Middle Aged , Prognosis , Retrospective Studies , Spinal Stenosis/surgery
5.
J Back Musculoskelet Rehabil ; 28(2): 267-76, 2015.
Article in English | MEDLINE | ID: mdl-25096312

ABSTRACT

BACKGROUND: Early identification of patients at risk of developing persistent low back pain (LBP) is crucial. OBJECTIVE: Aim of this study was to identify in patients with a new episode of LBP the time point at which those at risk of developing persistent LBP can be best identified. METHODS: Prospective cohort study of 315 patients presenting to a health practitioner with a first episode of acute LBP. Primary outcome measure was functional limitation. Patients were assessed at baseline, three, six, twelve weeks and six months looking at factors of maladaptive cognition as potential predictors. Multivariate logistic regression analysis was performed for all time points. RESULTS: The best time point to predict the development of persistent LBP at six months was the twelve-week follow-up (sensitivity 78%; overall predictive value 90%). Cognitions assessed at first visit to a health practitioner were not predictive. CONCLUSIONS: Maladaptive cognitions at twelve weeks appear to be suitable predictors for a transition from acute to persistent LBP. Already three weeks after patients present to a health practitioner with acute LBP cognitions might influence the development of persistent LBP. Therefore, cognitive-behavioral interventions should be considered as early adjuvant LBP treatment in patients at risk of developing persistent LBP.


Subject(s)
Chronic Pain/psychology , Cognition , Low Back Pain/psychology , Acute Disease , Adaptation, Physiological , Adult , Cohort Studies , Female , Follow-Up Studies , Humans , Male , Multivariate Analysis , Predictive Value of Tests , Risk Assessment , Sensitivity and Specificity
6.
J Arthroplasty ; 29(10): 1925-31, 2014 Oct.
Article in English | MEDLINE | ID: mdl-24927869

ABSTRACT

The number of septic and aseptic total hip arthroplasty (THA) revisions will increase, which involves a greater financial burden. We here provide a retrospective consecutive analysis of the major variable direct costs involved in revision THA for aseptic and septic failure. A total of 144 patients (30 septic, 114 aseptic) treated between January 1, 2009 and March 31, 2012 was included. The management of septic THA loosening is much more expensive than that of aseptic loosening ($14,379.8 vs. $5,487.4). This difference is mainly attributable to the two-stage exchange technique used for septic failure (hospital stay: 40.2 vs. 15.6 days) and significantly higher implant costs ($3,930.9 vs. $2,298.2). The septic implantation part is on average $3,384.6 more expensive than aseptic procedures (P < .001).


Subject(s)
Arthroplasty, Replacement, Hip/economics , Health Care Costs , Prosthesis-Related Infections/economics , Aged , Arthroplasty, Replacement, Hip/methods , Device Removal/economics , Female , Hip Prosthesis/economics , Humans , Male , Middle Aged , Prosthesis Failure , Reoperation/economics , Reoperation/methods , Retrospective Studies
7.
Eur Spine J ; 23(5): 985-90, 2014 May.
Article in English | MEDLINE | ID: mdl-24166020

ABSTRACT

PURPOSE: The sedimentation sign (SedSign) has been shown to discriminate well between selected patients with and without lumbar spinal stenosis (LSS). The purpose of this study was to compare the pressure values associated with LSS versus non-LSS and discuss whether a positive SedSign may be related to increased epidural pressure at the level of the stenosis. METHODS: We measured the intraoperative epidural pressure in five patients without LSS and a negative SedSign, and in five patients with LSS and a positive SedSign using a Codman(™) catheter in prone position under radioscopy. RESULTS: Patients with a negative SedSign had a median epidural pressure of 9 mmHg independent of the measurement location. Breath and pulse-synchronous waves accounted for 1-3 mmHg. In patients with monosegmental LSS and a positive SedSign, the epidural pressure above and below the stenosis was similar (median 8-9 mmHg). At the level of the stenosis the median epidural pressure was 22 mmHg. A breath and pulse-synchronous wave was present cranial to the stenosis, but absent below. These findings were independent of the cross-sectional area of the spinal canal at the level of the stenosis. CONCLUSIONS: Patients with LSS have an increased epidural pressure at the level of the stenosis and altered pressure wave characteristics below. We argue that the absence of sedimentation of lumbar nerve roots to the dorsal part of the dural sac in supine position may be due to tethering of affected nerve roots at the level of the stenosis.


Subject(s)
Epidural Space/pathology , Lumbar Vertebrae/physiopathology , Spinal Nerve Roots/physiopathology , Spinal Stenosis/physiopathology , Aged , Aged, 80 and over , Female , Humans , Lumbar Vertebrae/surgery , Male , Middle Aged , Pressure , Spinal Fusion , Spinal Nerve Roots/surgery , Spinal Stenosis/surgery
8.
Spine J ; 14(4): 667-74, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24055611

ABSTRACT

BACKGROUND CONTEXT: The nerve root sedimentation sign in transverse magnetic resonance imaging has been shown to discriminate well between selected patients with and without lumbar spinal stenosis (LSS), but the performance of this new test, when used in a broader patient population, is not yet known. PURPOSE: To evaluate the clinical performance of the nerve root sedimentation sign in detecting central LSS above L5 and to determine its potential significance for treatment decisions. STUDY DESIGN: Retrospective cohort study. PATIENT SAMPLE: One hundred eighteen consecutive patients with suspected LSS (52% women, median age 62 years) with a median follow-up of 24 months. OUTCOME MEASURES: Oswestry disability index (ODI) and back and leg pain relief. METHODS: We performed a clinical test validation study to assess the clinical performance of the sign by measuring its association with health outcomes. Subjects were patients referred to our orthopedic spine unit from 2004 to 2007 before the sign had been described. Based on clinical and radiological diagnostics, patients had been treated with decompression surgery or nonsurgical treatment. Changes in the ODI and pain from baseline to 24-month follow-up were compared between sedimentation sign positives and negatives in both treatment groups. RESULTS: Sixty-nine patients underwent surgery. Average baseline ODI in the surgical group was 54.7%, and the sign was positive in 39 patients (mean ODI improvement 29.0 points) and negative in 30 (ODI improvement 28.4), with no statistically significant difference in ODI and pain improvement between groups. In the 49 patients of the nonsurgical group, mean baseline ODI was 42.4%; the sign was positive in 18 (ODI improvement 0.6) and negative in 31 (ODI improvement 17.7). A positive sign was associated with a smaller ODI and back pain improvement than negative signs (both p<.01 on t test). CONCLUSIONS: In patients commonly treated with decompression surgery, the sedimentation sign does not appear to predict surgical outcome. In nonsurgically treated patients, a positive sign is associated with more limited improvement. In these cases, surgery might be effective, but this needs investigation in prospective randomized trials (Australian New Zealand Clinical Trial Registry, number ACTRN12610000567022).


Subject(s)
Lumbar Vertebrae/pathology , Pain/pathology , Spinal Nerve Roots/pathology , Spinal Stenosis/diagnosis , Aged , Australia , Cohort Studies , Decompression, Surgical , Disability Evaluation , Female , Humans , Lumbar Vertebrae/surgery , Male , Middle Aged , Pain/surgery , Prospective Studies , Retrospective Studies , Spinal Nerve Roots/surgery , Spinal Stenosis/pathology , Spinal Stenosis/surgery
9.
J Back Musculoskelet Rehabil ; 27(3): 281-9, 2014.
Article in English | MEDLINE | ID: mdl-24284275

ABSTRACT

BACKGROUND: There is little knowledge in the literature on the role of time-related variables for the prognosis of acute and subacute low back pain (LBP). OBJECTIVE: The aim of this study was to estimate the relationship between time-related LBP characteristics and prognostic factors for acute/subacute LBP. METHODS: We performed a prospective inception cohort study of 315 patients attending a health practitioner for acute/subacute LBP or recurrent LBP. One-tailed correlations were conducted between patient characteristics and time-related variables. RESULTS: The pattern of correlation between risk factors for and resources against persistent LBP differed between three time-related variables. 'Subacute LBP' and 'delayed presentation' were positively associated with psychological factors. Both indicators were negatively correlated with resources against development of persistent LBP. Moreover, 'delayed presentation' was related positively with occupational stressors. In contrast, 'recurrent LBP' was only related to more impaired health-related factors. CONCLUSIONS: Patients with current LBP waiting longer until seeking help in primary care have a more disadvantageous profile of occupational and psychological risk factors and lower resource levels. A similar but less pronounced pattern occurred in those with subacute LBP compared to those with acute LBP. Consideration of time characteristics of LBP may help to better understand LBP.


Subject(s)
Low Back Pain/diagnosis , Adolescent , Adult , Aged , Delayed Diagnosis , Female , Humans , Low Back Pain/psychology , Male , Middle Aged , Pain Measurement , Prognosis , Prospective Studies , Recurrence , Risk Factors , Time Factors , Young Adult
10.
Work ; 46(3): 297-311, 2013 Jan 01.
Article in English | MEDLINE | ID: mdl-24004738

ABSTRACT

OBJECTIVE: Occupational low back pain (LBP) is considered to be the most expensive form of work disability, with the socioeconomic costs of persistent LBP exceeding the costs of acute and subacute LBP by far. This makes the early identification of patients at risk of developing persistent LBP essential, especially in working populations. The aim of the study was to evaluate both risk factors (for the development of persistent LBP) and protective factors (preventing the development of persistent LBP) in the same cohort. PARTICIPANTS: An inception cohort of 315 patients with acute to subacute or with recurrent LBP was recruited from 14 health practitioners (twelve general practitioners and two physiotherapists) across New Zealand. METHODS: Patients with persistent LBP at six-month follow-up were compared to patients with non-persistent LBP looking at occupational, psychological, biomedical and demographic/lifestyle predictors at baseline using multiple logistic regression analyses. All significant variables from the different domains were combined into a one predictor model. RESULTS: A final two-predictor model with an overall predictive value of 78% included social support at work (OR 0.67; 95%CI 0.45 to 0.99) and somatization (OR 1.08; 95%CI 1.01 to 1.15). CONCLUSIONS: Social support at work should be considered as a resource preventing the development of persistent LBP whereas somatization should be considered as a risk factor for the development of persistent LBP. Further studies are needed to determine if addressing these factors in workplace interventions for patients suffering from acute, subacute or recurrent LBP prevents subsequent development of persistent LBP.


Subject(s)
Chronic Pain/prevention & control , Low Back Pain/prevention & control , Mental Health , Occupational Diseases/prevention & control , Adult , Chronic Pain/epidemiology , Chronic Pain/psychology , Female , Humans , Life Style , Longitudinal Studies , Low Back Pain/epidemiology , Low Back Pain/psychology , Male , Middle Aged , New Zealand , Occupational Diseases/epidemiology , Occupational Diseases/psychology , Pain Measurement , Predictive Value of Tests , Prognosis , Risk Factors , Social Support , Somatoform Disorders/epidemiology , Somatoform Disorders/prevention & control , Time Factors , Young Adult
11.
Behav Med ; 39(3): 80-9, 2013.
Article in English | MEDLINE | ID: mdl-23930900

ABSTRACT

Little is known about the course of recovery of acute low back pain (LBP) patients as a function of depression. In a prospective study, 286 acute LBP patients were assessed at baseline and followed up over 6 months. Recovery was defined as improvement in the Oswestry Disability Index (ODI). Repeated-measures analysis of covariance was employed with ODI as repeated factor, age, sex, and body mass index as covariates, depression and all other potential prognostic factors as between-subject factors. Of study participants, 18% were classified as depressive (>33 points on the Zung Self-Rating Depression Scale). Of 286 participants, 135 were lost to follow-up. In the longitudinal sample of 151 patients the course of recovery was slower in depressive patients. Depression was associated with LBP especially after 6 weeks and should therefore be included in screening instruments for acute LBP patients to identify those at risk of delayed recovery at an early stage.


Subject(s)
Acute Pain/diagnosis , Depression/complications , Low Back Pain/diagnosis , Recovery of Function , Acute Pain/complications , Acute Pain/psychology , Adult , Depression/psychology , Disability Evaluation , Female , Follow-Up Studies , Humans , Low Back Pain/complications , Low Back Pain/psychology , Male , Middle Aged , Prospective Studies , Treatment Outcome
13.
Int J Occup Saf Ergon ; 19(1): 29-40, 2013.
Article in English | MEDLINE | ID: mdl-23498709

ABSTRACT

The aim of this prospective cohort study was to identify modifiable protective factors of the progression of acute/subacute low back pain (LBP) to the persistent state at an early stage to reduce the socioeconomic burden of persistent LBP. Patients attending a health practitioner for acute/subacute LBP were assessed at baseline addressing occupational, personal and psychosocial factors, and followed up over 12 weeks. Pearson correlations were calculated between these baseline factors and the presence of nonpersistent LBP at 12-week follow-up. For those factors found to be significant, multivariate logistic regression analyses were performed. The final 3-predictor model included job satisfaction, mental health and social support. The accuracy of the model was 72%, with 81% of nonpersistent and 60% of persistent LBP patients correctly identified. Further research is necessary to confirm the role of different types of social support regarding their prognostic influence on the development of persistent LBP.


Subject(s)
Job Satisfaction , Low Back Pain/prevention & control , Mental Health , Social Support , Adult , Chronic Pain , Female , Humans , Male , Middle Aged , Predictive Value of Tests , Prospective Studies , Secondary Prevention , Surveys and Questionnaires , Young Adult
14.
Genes Nutr ; 8(1): 99-104, 2013 Jan.
Article in English | MEDLINE | ID: mdl-22639302

ABSTRACT

A high-fat diet (HFD) has been recognized as a risk factor for diseases such as dyslipidemia, atherosclerosis, obesity, and osteoporosis. However, studies analyzing gene expression after HFD in bone are rare. That prompted us to analyze the expression of selected genes in bone of 4-week-old diabetes-prone B(io)B(reeding) rats. Two breeding pairs were fed a HFD (+10 % tallow) or were fed a normal diet (ND; Ssniff R-Z) before mating and afterward during pregnancy. After the birth of progeny, parents continued to be given HFD or ND until the progeny was weaned (3 weeks). Thereafter, offspring were weaned and were fed the same food as their parents up to an age of 4 weeks. Body weight was measured at an age of 4 weeks, and subsequently 13 HFD rats and 13 ND rats were killed and the tibial bone was harvested to analyze the expression of 53 genes in bone. All rats fed HFD were significantly heavier than rats fed ND after 3 and 4 weeks. The diet also influenced the expression of genes in bone. There were significant differences in 20 out of 53 genes studied between rats fed HFD compared with rats fed ND. Four out of 20 had a lower and 17 out of 20 genes a higher expression in HFD rats, but differences in gene expression showed obvious differences between males and females. There were only two genes that were similarly different between males and females: Bmp4 and Atf4. Two genes, Foxg1 and Npy, were inversely expressed in males and females. It seems that the gene expression is differently regulated by diet during pregnancy and later in life between males and females. Nevertheless, it cannot be excluded that HFD also acts as an epigenetic factor in the development of offspring in utero.

15.
Int Arch Occup Environ Health ; 86(3): 261-9, 2013 Apr.
Article in English | MEDLINE | ID: mdl-22434236

ABSTRACT

PURPOSE: To reduce the socio-economic burden of persistent low back pain (LBP), factors influencing the progression of acute/subacute LBP to the persistent state must be identified at an early stage. METHODS: Prospective inception cohort study of patients attending a health practitioner for their first episode of acute/subacute or recurrent LBP. Patients were assessed at baseline addressing occupational, psychological, biomedical and demographic/lifestyle factors and followed up over 6 months. Multivariate logistic regression analysis was performed separately for the variables groups of the four different domains, controlling for age, gender and body mass index. The overall predictive value was calculated for the full regression models of the different domains. Finally, all significant variables from the different domains were combined into a final predictor model. RESULTS: The final four-predictor model predicted 51 % of variance of persistent LBP and included 'resigned attitude towards the job' (OR 1.73; 95 % CI 1.16-2.59), 'social support at work' (OR 0.54; 95 % CI 0.32-0.90), 'functional limitation' (OR 1.05; 95 % CI 1.01-1.10) and 'duration of LBP' (OR 1.04; 95 % CI 1.02-1.06). The accuracy of the model was 83 %, with 92 % of non-persistent and 67 % of persistent LBP patients correctly identified. CONCLUSIONS: In this study of patients with acute/subacute LBP, 'resigned attitude towards the job' increased the likelihood of persistent LBP at 6 month. Addressing this factor with workplace interventions has the potential to modify the outcome. In patients experiencing 'social support at work', the development of persistent LBP was less likely and might therefore be considered as potential resource for prevention of persistent LBP.


Subject(s)
Low Back Pain/epidemiology , Low Back Pain/psychology , Occupational Diseases/epidemiology , Occupational Diseases/psychology , Occupations/statistics & numerical data , Primary Health Care/statistics & numerical data , Adolescent , Adult , Aged , Attitude , Cohort Studies , Female , Health Behavior , Health Status , Humans , Job Satisfaction , Life Style , Male , Middle Aged , Occupational Health , Prognosis , Social Support , Socioeconomic Factors , Young Adult
16.
Spine (Phila Pa 1976) ; 38(5): E263-9, 2013 Mar 01.
Article in English | MEDLINE | ID: mdl-23222648

ABSTRACT

STUDY DESIGN: An experimental animal study. OBJECTIVE: To investigate histomorphometric and radiographical changes in the BB.4S rat model after PEEK (polyetheretherketone) nonfusion interspinous device implantation. SUMMARY OF BACKGROUND DATA: Clinical effectiveness of the PEEK nonfusion spine implant Wallis (Abbott, Bordeaux, France; now Zimmer, Warsaw, IN) is well documented. However, there is a lack of evidence on the long-term effects of this implant on bone, in particular its influence on structural changes of bone elements of the lumbar spine. METHODS: Twenty-four male BB.4S rats aged 11 weeks underwent surgery for implantation of a PEEK nonfusion interspinous device or for a sham procedure in 3 groups of 8 animals each: (1) implantation at level L4-L5; (2) implantation at level L5-L6; and (3) sham surgery. Eleven weeks postoperatively osteolyses at the implant-bone interface were measured via radiograph, bone mineral density of vertebral bodies was analyzed using osteodensitometry, and bone mineral content as well as resorption of the spinous processes were examined by histomorphometry. RESULTS.: Resorption of the spinous processes at the site of the interspinous implant was found in all treated segments. There was no significant difference in either bone density of vertebral bodies or histomorphometric structure of the spinous processes between adjacent vertebral bodies, between treated and untreated segments and between groups. CONCLUSION: These findings indicate that resorption of spinous processes because of a result of implant loosening, inhibit the targeted load redistribution through the PEEK nonfusion interspinous device in the lumbar spinal segment of the rat. This leads to reduced long-term stability of the implant in the animal model. These results suggest that PEEK nonfusion interspinous devices like the Wallis implants may have time-limited effects and should only be used for specified indications.


Subject(s)
Intervertebral Disc/surgery , Lumbar Vertebrae/surgery , Prosthesis Implantation/instrumentation , Total Disc Replacement/instrumentation , Animals , Benzophenones , Bone Density , Bone Resorption/diagnostic imaging , Bone Resorption/etiology , Intervertebral Disc/diagnostic imaging , Intervertebral Disc/pathology , Ketones , Lumbar Vertebrae/diagnostic imaging , Lumbar Vertebrae/pathology , Male , Osseointegration , Polyethylene Glycols , Polymers , Prosthesis Design , Prosthesis Failure , Prosthesis Implantation/adverse effects , Radiography , Rats , Time Factors , Total Disc Replacement/adverse effects
17.
PLoS One ; 7(11): e50211, 2012.
Article in English | MEDLINE | ID: mdl-23209677

ABSTRACT

STUDY DESIGN: We assessed volume following nucleoplasty disc decompression in lower lumbar spines from cadaveric pigs using 7.1Tesla magnetic resonance imaging (MRI). PURPOSE: To investigate coblation-induced volume reductions as a possible mechanism underlying nucleoplasty. METHODS: We assessed volume following nucleoplastic disc decompression in pig spines using 7.1-Tesla MRI. Volumetry was performed in lumbar discs of 21 postmortem pigs. A preoperative image data set was obtained, volume was determined, and either disc decompression or placebo therapy was performed in a randomized manner. Group 1 (nucleoplasty group) was treated according to the usual nucleoplasty protocol with coblation current applied to 6 channels for 10 seconds each in an application field of 360°; in group 2 (placebo group) the same procedure was performed but without coblation current. After the procedure, a second data set was generated and volumes calculated and matched with the preoperative measurements in a blinded manner. To analyze the effectiveness of nucleoplasty, volumes between treatment and placebo groups were compared. RESULTS: The average preoperative nucleus volume was 0.994 ml (SD: 0.298 ml). In the nucleoplasty group (n = 21) volume was reduced by an average of 0.087 ml (SD: 0.110 ml) or 7.14%. In the placebo group (n = 21) volume was increased by an average of 0.075 ml (SD: 0.075 ml) or 8.94%. The average nucleoplasty-induced volume reduction was 0.162 ml (SD: 0.124 ml) or 16.08%. Volume reduction in lumbar discs was significant in favor of the nucleoplasty group (p<0.0001). CONCLUSIONS: Our study demonstrates that nucleoplasty has a volume-reducing effect on the lumbar nucleus pulposus in an animal model. Furthermore, we show the volume reduction to be a coblation effect of nucleoplasty in porcine discs.


Subject(s)
Diskectomy, Percutaneous/methods , Magnetic Resonance Imaging/methods , Animals , Image Processing, Computer-Assisted , Intervertebral Disc/pathology , Lumbar Vertebrae/pathology , Models, Animal , Models, Statistical , Orthopedics/methods , Placebos , Swine , Treatment Outcome
18.
PLoS One ; 7(6): e38981, 2012.
Article in English | MEDLINE | ID: mdl-22768054

ABSTRACT

BACKGROUND: Because inbred rat strains are widely used as laboratory models, knowledge of phenotypic and genetic variations between strains will be useful to obtain insight into the relationship between different strains. METHODS AND RESULTS: We studied phenotypic traits: of each strain--BN/K, DA/K and WOKW--10 male rats were studied for body weight and serum constituents at an age of 10 and 30 weeks. In addition, a total of 95 rats were studied for life expectancy. At an age of 30 weeks, these male rats were killed by an overdose of anesthetic (Sevofluran, Abbott), and the subcutaneous and visceral adipose tissue as well as bone tissue were removed to study the expression of 20 genes. There were significant differences in body weight, serum lipids and leptin at an age of 30 weeks between strains. Regarding life expectancy, BN rats lived longest (1072±228d). The highest gene expression was found in bone of BN rats. In adipose tissues, Nfkb1 is only expressed in subcutaneous adipocytes, and 5 genes, Col2a1, Mmp9, Tnfa, Ins1 and Cyp24a1, are not expressed in adipocytes. The ranking BN = DA>WOKW was observed in only one gene in subcutaneous (Fto) and visceral adipocytes (Col6a1). There were no significant differences in gene expression of one gene in subcutaneous adipocytes and of 3 genes in visceral adipocytes. Comparing the gene expression in visceral and subcutaneous adipocytes, only one gene showed a comparable behavior (Bmp1). CONCLUSION: From these results, it can be concluded that obvious phenotypic differences are caused by genetic differences between three rat strains, BN, DA and WOKW, as supported by gene expression studies in bone and adipose tissues. Especially BN rats can be used to study the genetic basis of long life.


Subject(s)
Gene Expression Regulation , Adipocytes/metabolism , Adiposity/genetics , Animals , Gene Expression Profiling , Male , Organ Specificity/genetics , Phenotype , Rats , Rats, Inbred Strains
19.
Ind Health ; 50(4): 288-98, 2012.
Article in English | MEDLINE | ID: mdl-22673362

ABSTRACT

This study examines predictors of sickness absence in patients presenting to a health practitioner with acute/ subacute low back pain (LBP). Aims of this study were to identify baseline-variables that detect patients with a new LBP episode at risk of sickness absence and to identify prognostic models for sickness absence at different time points after initial presentation. Prospective cohort study investigating 310 patients presenting to a health practitioner with a new episode of LBP at baseline, three-, six-, twelve-week and six-month follow-up, addressing work-related, psychological and biomedical factors. Multivariate logistic regression analysis was performed to identify baseline-predictors of sickness absence at different time points. Prognostic models comprised 'job control', 'depression' and 'functional limitation' as predictive baseline-factors of sickness absence at three and six-week follow-up with 'job control' being the best single predictor (OR 0.47; 95%CI 0.26-0.87). The six-week model explained 47% of variance of sickness absence at six-week follow-up (p<0.001). The prediction of sickness absence beyond six-weeks is limited, and health practitioners should re-assess patients at six weeks, especially if they have previously been identified as at risk of sickness absence. This would allow timely intervention with measures designed to reduce the likelihood of prolonged sickness absence.


Subject(s)
Low Back Pain/diagnosis , Primary Health Care , Sick Leave , Adult , Depression/psychology , Disability Evaluation , Episode of Care , Female , Humans , Internal-External Control , Low Back Pain/therapy , Male , Middle Aged , Prognosis , Risk Factors , Time Factors , Young Adult
20.
Evid Based Spine Care J ; 3(3): 51-6, 2012 Aug.
Article in English | MEDLINE | ID: mdl-23526906

ABSTRACT

Recurrent cervical symptoms frequently occur after cervical disc replacement and fusion. To date, no algorithm for the diagnostic assessment of these symptoms has been established. We present a case report and review of the literature to illustrate the need for interdisciplinary diagnostics in recurrent cervicobrachialgia without pathological cervical imaging. The hospital chart, medical history, physical examination, and imaging of a single patient were reviewed. A 53-year-old man with preexisting cervical disc replacement and fusion presented with a new episode of cervicobrachialgia after a 2-year symptom-free interval. Cervical magnetic resonance imaging (MRI) showed no pathological findings. Six months later the patient reported increasing symptoms including numbness and weakness of the right arm. Repeated cervical MRI and thoracic computed tomography revealed cervical metastases with intraspinal tumor growth and an underlying extensive small cell bronchial carcinoma. In recurrent cervicobrachialgia, without pathological cervical imaging, interdisciplinary diagnostics are needed. Basic diagnostic tests may assist to exclude severe non-vertebrogenic pathologies.

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