Real-time assessment of anteroposterior stability of spinal segments

Purpose

While anteroposterior instability of spinal segments is regarded as an important biomechanical aspect in the clinical evaluation of lumbar pathologies, the reliability of the available diagnostic tools is limited and an intraoperative method to quantify stability is lacking. The aim of this study was to develop and validate an instrument to measure the anteroposterior stability of a spinal segments in real-time.

Methods

Torsi of five fresh-frozen human cadavers were used for this study. After pedicle screw insertion, a specifically modified reposition tool composed with load and linear sensors was used to measure the segmental anteroposterior motion caused by 100 N anterior and posterior force during 5 loading cycles on either side of the instrumentation by two different operators. The spinal segments were then resected from the torsi and anteroposterior loading with ± 100 N was repeated in an advanced biomechanical spine testing setup as a reference measurement. The Inter-correlation coefficient (ICC) was used for validation of the “intraoperative” device.

Results

Inter-operator repeatability of the measurements showed an ICC of 0.93 (p < 0.0001) and the bilateral (left–right) comparison had an ICC of 0.73 (p < 0.0001). The ICC resulting from the comparison to the reference measurement was 0.82 (p < 0.0001) without offset correction, and 0.9 (p < 0.0001) with offset correction. The ICC converged at this value already after two of the five performed loading cycles.

Conclusion

An accurate and reliable measurement tool is developed and validated for real-time quantification of anteroposterior stability of spinal segments and serves as a basis for future intraoperative use.

     

Value of abdominal ultrasonography for indication of cholecystectomy]

A review of the gall-bladder content of the 193 patients that underwent a cholecystectomy at the University Hospital of Lausanne, Switzerland, in 1977, was done in order to find out the diagnostic accuracy of sonographic examination of the gall-bladder, oral cholecystography and intravenous cholangiography. Sonographic examination of the gall-bladder proofed to be accurate in 92.5% of 109 cases. We found a false negative rate of 4.5% (5 cases) and a false positive rate of 1% (1 case) as well as an indeterminate rate of 2% (2 cases). In 37% (46 cases) of the 124 patients that underwent oral cholecystography and/or intravenous cholangiography the gall-bladder was not visualized. Sonographic examination of gall-bladder is free of side effects and can be done on emergency, on jaundiced or pregnant patients, and it is enough reliable for the surgeon to make a decision to operate the gall-bladder. Low cost of the procedure is another point in favour of sonographic examination of the gall-bladder.     

Residual motion of cortical versus pedicle screw constructs after decompression,interbody fusion and cross-link augmentation

Purpose

To compare the residual range of motion (ROM) of cortical screw (CS) versus pedicle screw (PS) instrumented lumbar segments and the additional effect of transforaminal interbody fusion (TLIF) and cross-link (CL) augmentation.

Methods

ROM of thirty-five human cadaver lumbar segments in flexion/extension (FE), lateral bending (LB), lateral shear (LS), anterior shear (AS), axial rotation (AR), and axial compression (AC) was recorded. After instrumenting the segments with PS (n = 17) and CS (n = 18), ROM in relation to the uninstrumented segments was evaluated without and with CL augmentation before and after decompression and TLIF.

Results

CS and PS instrumentations both significantly reduced ROM in all loading directions, except AC. In undecompressed segments, a significantly lower relative (and absolute) reduction of motion in LB was found with CS 61% (absolute 3.3°) as compared to PS 71% (4.0°; p = 0.048). FE, AR, AS, LS, and AC values were similar between CS and PS instrumented segments without interbody fusion. After decompression and TLIF insertion, no difference between CS and PS was found in LB and neither in any other loading direction. CL augmentation did not diminish differences in LB between CS and PS in the undecompressed state but led to an additional small AR reduction of 11% (0.15°) in CS and 7% (0.05°) in PS instrumentation.

Conclusion

Similar residual motion is found with CS and PS instrumentation, except of slightly, but significantly inferior reduction of ROM in LB with CS. Differences between CS and PS in diminish with TLIF but not with CL augmentation.

     

Determinants of quality of life in community-dwelling older adults: comparing three cut-offs on the excellent-to-poor spectrum

Purpose

The aim of this study was to identify modifications in health, economic and social determinants of quality of life (QoL) in community-dwelling older adults when using different cut-offs to defining favorable QoL.

Methods

Data of year 2011 annual assessment in 1003 older men and women from the Lc65+ cohort study were used. Overall QoL was self-rated as ‘excellent,’ ‘very good,’ ‘good,’ ‘fair,’ or ‘poor.’ To identify significant health (self-rated health, SF-12v2 physical and mental health), economic (financial situation), and social (living with others, being socially supported, emotional support, group activities participation) determinants of QoL, a cut-off was set at three different positions to define favorable QoL on the ‘excellent’ to ‘poor’ spectrum: at least ‘good’ (model 1); at least ‘very good’ (model 2); and ‘excellent’ only (model 3).

Results

In all three models, bivariable analyses indicated significant associations between QoL and at least one variable from each health, economic, and social dimension. In multivariable analyses, only health-related variables remained significantly associated with QoL in model 1. Model 3 additionally retained financial situation. In model 2, QoL was positively associated with physical health [odds ratio (OR) 1.10, p < 0.001], mental health (OR 1.12, p < 0.001), self-rated health (OR 2.43, p < 0.001), group activities participation (OR 1.43, p = 0.037), being socially supported (OR 1.58, p = 0.024), and not reporting financial difficulties (OR 1.76; p = 0.036).

Conclusions

Using different cut-offs to defining favorable QoL results in important changes in the number and type of significant health, economic and social determinants. A cut-off between ‘good’ and ‘very good’ appears to best reflect the multidimensional nature of QoL.

     

Residual motion of different posterior instrumentation and interbody fusion constructs

Purpose

To elucidate residual motion of cortical screw (CS) and pedicle screw (PS) constructs with unilateral posterior lumbar interbody fusion (ul-PLIF), bilateral PLIF (bl-PLIF), facet-sparing transforaminal lumbar interbody fusion (fs-TLIF), and facet-resecting TLIF (fr-TLIF).

Methods

A total of 35 human cadaver lumbar segments were instrumented with PS (n = 18) and CS (n = 17). Range of motion (ROM) and relative ROM changes were recorded in flexion/extension (FE), lateral bending (LB), axial rotation (AR), lateral shear (LS), anterior shear (AS), and axial compression (AC) in five instrumentational states: without interbody fusion (wo-IF), ul-PLIF, bl-PLIF, fs-TLIF, and fr-TLIF.

Results

Whereas FE, LB, AR, and AC noticeably differed between the instrumentational states, AS and LS were less prominently affected. Compared to wo-IF, ul-PLIF caused a significant increase in ROM with PS (FE + 42%, LB + 24%, AR + 34%, and AC + 77%), however, such changes were non-significant with CS. ROM was similar between wo-IF and all other interbody fusion techniques. Insertion of a second PLIF (bl-PLIF) significantly decreased ROM with CS (FE -17%, LB -26%, AR -20%, AC -51%) and PS (FE − 23%, LB − 14%, AR − 20%, AC − 45%,). Facet removal in TLIF significantly increased ROM with CS (FE + 6%, LB + 9%, AR + 17%, AC of + 23%) and PS (FE + 7%, AR + 12%, AC + 13%).

Conclusion

bl-PLIF and TLIF show similarly low residual motion in both PS and CS constructs, but ul-PLIF results in increased motion. The fs-TLIF technique is able to further decrease motion compared to fr-TLIF in both the CS and PS constructs.

     

Photodetection and photodynamic therapy of ‘early’ squamous cell carcinomas of the pharynx,oesophagus and tracheo-bronchial tree

The efficacy of photodynamic therapy (PDT) alone was evaluated on 41 early squamous cell carcinomas of the pharynx (10), oesophagus (15) and tracheo-bronchial tree (16). All lesions but two were synchronous second primaries in ENT-patients suffering from a more extensive cancer, governing the overall oncological prognosis.Photofrin I (3 mg/kg) or Photofrin II (2 mg/kg) were injected 72 h prior to the red light irradiation, supplied by an argon pumped dye laser. A diffusing cylinder was used to obtain a homogeneous light distribution at the tumour site (60 J to 150 J/cm²). In the oesophagus and bronchi, the results are good for cancers staged in situ or microinvasive at endoscopy (two recurrencies for 23 lesions treated). For more advanced cancers (submucosal in the oesophagus or invading the bronchial cartilage), the results are less satisfactory (three recurrencies for eight lesions treated). In the pharynx where light dosimetry is more difficult, the rate of recurrencies is higher (3/10 lesions treated). In the bronchi (one case) and oesophagus (one case), the longest disease-free survival is now 5 years.The irradiation of a non-cancerous zone of normal buccal mucosa on 25 patients having received HPD showed necrosis in all cases with light doses as low as 50mW/cm² for 20 min (60 J cm^–2), even with Photofrin II.We encountered six complications (three cicatricial stenosis, two fistulae, one severe sunburn), most of them resulting from the lack of selectivity of HPD. According to these experiments, PDT is efficient at destroying early squamous cell carcinomas in the pharynx, oesophagus and bronchi, but the tumour selectivity of HPD is poor in the digestive tract lined with squamous cell epithelium. The only hope for the future lies in the synthesis of a more selective and more stable photosensitizer. This discussion reviews possible directions of research for the development of new dyes (cationic dyes, dyes attached to monoclonal antibodies, etc), for PDT and hyperthermia, for photodetection of early cancers using a fluoro-endoscope, and finally, for tumour depth profiling in hollow organs using lasers of different wavelengths.     

Life-course socioeconomic environment and health risk behaviours. A multilevel small-area analysis of young-old persons in an urban neighbourhood in Lausanne, Switzerland

With a life expectancy at the age of 65 of around 20 years, damaging health risk behaviours of young-old adults have become a target for preventive actions. Such risk factors necessitate an accurate understanding of the present and past socioeconomic conditions associated with health risk behaviours. The aim of our study is to assess the impact of certain life events as well as economic and environmental factors on health risk behaviours. We included 1309 participants of the Lausanne Cohort Lc65+ aged 65-70 years and employed logistic regression analyses, with individuals nested within areas. The results illustrate the influences of socioeconomic factors from childhood to young-old age. Life experiences in adulthood and economic resources in young-old age are both associated with unfavourable health behaviours. Neighbourhood is a modest determinant as well, particularly regarding alcohol consumption. Therefore, prevention against health risk behaviours should focus on population subgroups defined on the basis of their socioeconomic and living contexts.     

Waiting for a breast biopsy. Psychosocial consequences and coping strategies

OBJECTIVE: The aim of this pilot/feasibility study was to describe the experience of women presenting with a suspicious mammogram who are waiting for a breast biopsy and to identify those at risk for distress. METHODS: Participants (n=25) were interviewed at two time points: immediately after being put on the waiting list (T1) and again immediately before their biopsy approximately 6 weeks later (T2). Self-report measures of distress and coping were used. Perceived personal risk of a positive biopsy finding and information needs were assessed through open-ended questions. RESULTS: Distress levels were high in this sample. Using cognitive-avoidant coping strategies, being employed, history of previous biopsies, and having a family history of breast cancer were associated with greater distress. Perceived personal risk of a positive biopsy finding was overestimated in one half of the cases and was correlated with greater distress. CONCLUSION: Waiting period between suspicious mammogram and breast biopsy may be a time of high distress for many women.