Protein biomarkers and alternatively methylated cell-free DNA detect early stage pancreatic cancer

OBJECTIVE

Pancreatic ductal adenocarcinoma (PDAC) is commonly diagnosed at an advanced stage. Liquid biopsy approaches may facilitate detection of early stage PDAC when curative treatments can be employed.

DESIGN

To assess circulating marker discrimination in training, testing and validation patient cohorts (total n=426 patients), plasma markers were measured among PDAC cases and patients with chronic pancreatitis, colorectal cancer (CRC), and healthy controls. Using CA19-9 as an anchor marker, measurements were made of two protein markers (TIMP1, LRG1) and cell-free DNA (cfDNA) pancreas-specific methylation at 9 loci encompassing 61 CpG sites.

RESULTS

Comparative methylome analysis identified nine loci that were differentially methylated in exocrine pancreas DNA. In the training set (n=124 patients), cfDNA methylation markers distinguished PDAC from healthy and CRC controls. In the testing set of 86 early stage PDAC and 86 matched healthy controls, CA19-9 had an area under the receiver operating characteristic curve (AUC) of 0.88 (95% CI 0.83 to 0.94), which was increased by adding TIMP1 (AUC 0.92; 95% CI 0.88 to 0.96; p=0.06), LRG1 (AUC 0.92; 95% CI 0.88 to 0.96; p=0.02) or exocrine pancreas-specific cfDNA methylation markers at nine loci (AUC 0.92; 95% CI 0.88 to 0.96; p=0.02). In the validation set of 40 early stage PDAC and 40 matched healthy controls, a combined panel including CA19-9, TIMP1 and a 9-loci cfDNA methylation panel had greater discrimination (AUC 0.86, 95% CI 0.77 to 0.95) than CA19-9 alone (AUC 0.82; 95% CI 0.72 to 0.92).

CONCLUSION

A combined panel of circulating markers including proteins and methylated cfDNA increased discrimination compared with CA19-9 alone for early stage PDAC.

Age-related changes in human cervical, thoracal and lumbar intervertebral disc exhibit a strong intra-individual correlation

INTRODUCTION

Intervertebral disc (IVD) degeneration is characterized as a multifactorial disease, in which the hereditary background is thought to be of high importance. Accordingly, one would expect all spinal levels (lumbar/cervical/thoracal) to be affected by above-average disc degeneration in genetically predisposed individuals. The aim of this study, therefore, was to analyze the amount of degenerative changes in different spine levels in humans from different ages.

MATERIALS AND METHODS

In detail, the presence, localization and abundance of histomorphological changes in the annulus fibrosus (AF) and nucleus pulposus (NP) in the cervical (C5/C6), thoracic (T2/T3) and lumbar (L2/L3) spine were investigated in complete autopsy IVD specimens (47 individuals) covering a complete age range (0-95 years).

RESULTS

Results indicate that the highest degree of histo-degenerative changes were observed in the NP in all spine levels and showed an age-related expression pattern. With regard to the different spine levels, lumbar disc specimen showed significantly more degenerative changes compared to cervical and thoracic discs, whereas no statistical difference was observed between cervical and thoracic discs. In summary, highest grades of degeneration were observed in lumbar discs (especially in the NP). Intra-individual correlations between the degeneration score in the different levels showed a significant individual concordance.

CONCLUSIONS

The intra-individual correlation of degenerative changes in all three examined spine regions further supports the notion that individual, i.e. genetic factors are strong predisposing factor for the development of age-related disc alterations.

Translaminar facet joint screws to enhance segmental fusion of the lumbar spine

From 1984 to 1988, 70 consecutive lumbar and lumbosacral spine fusions enhanced with translaminar facet joint screws were performed for segmental degenerative disease. Twenty patients had partial decompression of central stenosis, 15 concomitant discectomy, and 19 lateral nerve root decompression. The mean time to fusion was 4.5 months (range 2-7 months). At followup (average 45 months; range 24-74 months) 98.5% were judged to have solid fusion. Satisfactory results were observed in 84% of cases, 91% without previous surgery and 75% after previous discectomy. Supplementation of posterolateral fusion by translaminar facet screws significantly improved time to fusion, fusion rate, and clinical outcomes with no significant increased complications.

Cell-seeded polyurethane-fibrin structures--a possible system for intervertebral disc regeneration

Nowadays, intervertebral disc (IVD) degeneration is one of the principal causes of low back pain involving high expense within the health care system. The long-term goal is the development of a medical treatment modality focused on a more biological regeneration of the inner nucleus pulposus (NP). Hence, interest in the endoscopic implantation of an injectable material took center stage in the recent past. We report on the development of a novel polyurethane (PU) scaffold as a mechanically stable carrier system for the reimplantation of expanded autologous IVD-derived cells (disc cells) to stimulate regenerative processes and restore the chondrocyte-like tissue within the NP. Primary human disc cells were seeded into newly developed PU spheroids which were subsequently encapsulated in fibrin hydrogel. The study aims to analyze adhesion properties, proliferation capacity and phenotypic characterization of these cells. Polymerase chain reaction was carried out to detect the expression of genes specifically expressed by native IVD cells. Biochemical analyses showed an increased DNA content, and a progressive enhancement of total collagen and glycosaminoglycans (GAG) was observed during cell culture. The results suggest the synthesis of an appropriate extracellular matrix as well as a stable mRNA expression of chondrogenic and/or NP specific markers. In conclusion, the data presented indicate an alternative medical approach to current treatment options of degenerated IVD tissue.

What comprises a good outcome in spinal surgery? A preliminary survey among spine surgeons of the SSE and European spine patients

Standardized and validated self-administered outcome-instruments are broadly used in spinal surgery. Despite a plethora of articles on outcome research, no systematic evaluation is available on what actually comprises a good outcome in spinal surgery from the patients' and surgeons' perspective, respectively. However, this is a prerequisite for improving outcome instruments. In performing a cross-sectional survey among spine patients from different European regions and spine surgeons of the SSE, the study attempted (1) to identify the most important domains determining a good outcome from a patients' as well as a surgeon's perspective, and (2) to explore regional differences in the identified domains. For this purpose, a structured interview was performed among 30 spine surgeons of the SSE and 353 spine surgery patients (representing Northern, Central and Southern Europe) to investigate their criteria for a good outcome. A qualitative and descriptive approach was used to evaluate the data. Results revealed a high agreement on what comprises a good outcome among surgeons and patients, respectively. The main parameters determining good outcome were achieving the patients' expectations/satisfaction, pain relief, improvement of disability and social reintegration. Younger patients more often expected a complete pain relief, an improved work capacity, and better social life participation. Patients in southern Europe more often wanted to improve work capacity compared to those from central and northern European countries. No substantial differences were found when patients' and surgeons' perspective were compared. However, age and differences in national social security and health care system ("black flags") have an impact on what is considered a good outcome in spinal surgery.

Predictors of multidimensional outcome after spinal surgery

The variables identified as predictors of surgical outcome often differ depending on the specific outcome variable chosen to designate "success". A short set of multidimensional core outcome measures was recently developed, in which each of the following domains was addressed with a single question and then combined in an index: pain, function, symptom-specific well-being, general well-being (quality of life), disability (work and social). The present study examined the factors that predicted surgical outcome as measured using the multidimensional core measures. 163 spinal surgery patients (mixed indications) completed questionnaires before and 6 months after surgery enquiring about demographics, medical/clinical history, fear-avoidance beliefs (FABQ), depression (Zung self-rated depression), and the core measures domains. Multiple regression analyses were used to identify predictor variables for each core domain and for the multidimensional combined core-set index. The combination of baseline symptoms, medical variables (pain duration, previous spine operations, number of levels treated, operative procedure) and psychosocial factors (FABQ and Zung depression) explained 34% of the variance in the core measures index (P < 0.001). With regard to the individual domain items, the medical variables were better in predicting the items "pain" and "symptom-specific well-being" (R (2) = 6-7%) than in predicting "function", "general well-being" or "disability" (each R (2) < 4%). The inverse pattern was shown for the psychosocial predictors, which accounted for in each case approximately 20% variance in "function", "general well-being" and "disability" but only 12-14% variance in "pain" and "symptom-specific well-being". Further to previous studies establishing the sensitivity to change of the core-set, we have shown that a large proportion of the variance in its scores after surgery could be predicted by "well-known" medical and psychosocial predictor variables. This substantiates the recommendation for its further use in registry systems, quality management projects, and clinical trials.

Lumbar spinal stenosis: Assessment of cauda equina involvement by electrophysiological recordings

The objective of this study was to investigate the relationship between electrophysiological recordings and clinical as well as radiological findings in patients suggestive to suffer from a lumbar spinal stenosis (LSS). We hypothesise that the electrophysiological recordings, especially SSEP, indicate a lumbar nerve involvement that is complementary to the neurological examination and can provide confirmatory information in less obvious clinical cases. In a prospective cohort study, 54 patients scheduled for surgery due to LSS were enrolled in an unmasked, uncontrolled trial. All patients were assessed by neurological examination, electrophysiological recordings, and magnetic resonance imaging (MRI) of the lumbar spine. The electrophysiological recordings focused on spinal lumbar nerve involvement.

RESULTS

About 88% suffered from a multisegmental LSS and 91% of patients respectively complained of chronic lower back pain and/or leg pain for more than 3 months, combined with a restriction in walking distance. The neurological examination revealed only a few patients with sensory and/or motor deficits while 87% of patients showed pathological electrophysiological recordings (abnormal tibial SSEP in 78% of patients, abnormal H-reflex in 52% of patients).

CONCLUSIONS

Whereas the clinical examination, even in severe LSS, showed no specific sensory-motor deficit, the electrophysiological recordings indicated that the majority of patients had a neurogenic disorder within the lumbar spine. By the pattern of bilateral pathological tibial SSEP and pathological reflexes associated with normal peripheral nerve conduction, LSS can be separated from a demyelinating polyneuropathy and mono-radiculopathy. The applied electrophysiological recordings, especially SSEP, can confirm a neurogenic claudication due to cauda equina involvement and help to differentiate neurogenic from vascular claudication or musculo-skeletal disorders of the lower limbs. Therefore, electro-physiological recordings provide additional information to the neurological examination when the clinical relevance of a radiologically-suspected LSS needs to be confirmed.

Reliability of perioperative SSEP recordings in spine surgery

OBJECTIVE

The reproducibility and clinical reliability of perioperative somatosensory-evoked potentials (SSEP) were prospectively evaluated in uneventful scoliosis surgery. The influence of anesthesia owing to induction of total intravenous anesthesia (TIVA) upon preoperative SSEP and the variability of intraoperative SSEP were calculated. The potential effect of spine surgery was assessed by comparing pre- to postoperative SSEP.

METHODS

A total of 2,143 pre-, intra- and postoperative tibial and median SSEP recorded in 25 patients undergoing spine surgery owing to idiopathic scoliosis were analyzed. The anesthesia protocol consisted of a computerized target controlled infusion (TCI) device for propofol and intravenous application of an opioid.

RESULTS

Anesthesia induced a significant and comparable prolongation of the tibial SSEP onset, P40 and P60 latencies, while the N50 latency was less changed. Throughout anesthesia, latencies of median (onset, N20, P25 and N35) and tibial (onset, P40, N50 and P60) SSEP showed mean variations of less than 6%. The intraoperative SSEP amplitudes were less stable with a relative standard deviation of 30-40%. In uneventful spine surgery, the postoperative tibial SSEP were not significantly changed in comparison to preoperative recordings.

CONCLUSIONS

By using a standardized anesthesia protocol, the impact of anesthesia on preoperative SSEP can be predicted. Furthermore, the controlled application of sedatives and analgesics allows recording of stable SSEP parameters for intraoperative monitoring purposes. As in uneventful spine surgery pre- to postoperative SSEP are unchanged the latter comparison can be applied as an additional perioperative neuromonitoring procedure to assess the influence of spine surgery or other invasive interventions on spinal cord function.

2002 SSE Award Competition in Basic Science: expression of major matrix metalloproteinases is associated with intervertebral disc degradation and resorption

During the process of degeneration, the intervertebral disc (IVD) shows a progressive and significant reduction in height due to tissue resorption. Intradiscal clefts and tears are major hallmarks of disc degeneration. Matrix-degrading enzymes such as matrix metalloproteinases (MMPs) are assumed to play a pivotal role in disc tissue degradation and resorption. The objective of this study was therefore to investigate the potential role of MMPs in extracellular matrix degradation leading to disc degeneration. This study was conducted on 30 formalin-fixed and EDTA-decalcified complete cross-sections of lumbar IVDs from cadavers of individuals aged between 0 and 86 years. Tissue sections were used for the immunolocalization of MMPs-1, -2, -3 and -9. The number of labeled cells was assessed by morphometric analyses, and was statistically correlated with the formation of clefts and tears, cellular proliferation, granular matrix changes and mucous degeneration. Furthermore, 30 disc specimens obtained during spinal surgery were used for in situ hybridization of MMP-2 and -3-mRNA. In addition, the enzymatic gelatinolytic activity was determined by in situ zymography in autopsy material. Immunohistochemistry showed the intradiscal expression of all four MMPs, which was confirmed by in situ hybridization, providing clear evidence for the synthesis of the enzymes within nucleus pulposus and annulus fibrosus cells. Gelatinolytic enzymatic activity was verified by in situ zymography. IVDs from infants and young adolescents remained almost completely unlabeled for all MMPs tested, while more MMPs-1 and -3 were seen in disc cells of younger adults than in those of a more advanced age; MMP-2 remained unchanged over the adult age periods, and MMP-9 was expressed in only relatively few cells. This pattern significantly correlated with the occurrence of clefts and tears. This correlation was strongest for MMP-1 ( P<0.0001), MMP-2 ( P<0.0017) and MMP-3 ( P<0.0005) in the nucleus, and MMP-1 ( P<0.0001) and MMP-2 ( P<0.038) in the annulus. In parallel, the proliferation of disc cells and matrix degeneration (granular changes and mucous degeneration) were related to MMP expression. Likewise, enzymatic activity was seen in association with cleft formation. Our data suggest that major MMPs play an important role in the degradation of the IVD. This is evidenced by the high correlation of MMP expression with the formation of clefts and tears. These findings implicate a leading function for MMPs in IVD degeneration resulting in the loss of normal disc function, eventually leading to low-back pain.

[Percutaneous transpedicular vertebroplasty for treatment of osteoporosis-induced vertebral fractures]

Osteoporosis plays an increasing medical, social, and economic role in our society. Vertebral body fractures are the most common fractures, along with fractures around the hip joint, and fractures of the distal radius due to osteoporosis. An osteoporotic vertebral compression fracture can lead to incapacitating back pain and immobility and often requires in-hospital treatment. Vertebroplasty is an effective procedure consisting of the percutaneous injection of polymethylmethacrylate (PMMA) cement into vertebral bodies. Preliminary studies showed promising clinical results with this new technique. As there is a high incidence of cement leakage during the injection of the cement, we prefer to perform the procedure under computed tomography control with a fluoro-CT-option. Furthermore, we recommend that the procedure is only done in collaboration with a spine surgeon. In case of a neurological complication, immediate decompression of the spinal canal is mandatory. Vertebroplasty is a very promising, effective and safe method for the treatment for osteoporotic vertebral compression fractures. Based on our preliminary results, this method can be recommended for a more widespread clinical use.

Selective nerve root blocks for the treatment of sciatica: evaluation of injection site and effectiveness--a study with patients and cadavers

PURPOSE

To relate different types of radiographic contrast material distributions to anatomic compartments by using cadaveric specimens and to relate the injection site to treatment-induced discomfort and therapeutic effect.

MATERIALS AND METHODS

The contrast material distributions of selective nerve root blocks (SNRBs) in 36 patients (13 women, 23 men; mean age, 52 years; age range, 22-88 years) were graded by two radiologists in conference as type 1 (tubular appearance), type 2 (nerve root visible as filling defect), or type 3 (nerve root not visible). These patterns were correlated with pain reduction after 15 minutes and 2 weeks (with a visual analogue scale of 100-mm length). In addition, 30 nerve roots were injected with iodine-containing contrast material and blue dye in three cadaveric specimens. Radiographs were compared with anatomic sections.

RESULTS

After 15 minutes and 2 weeks, 75% and 86% of the patients, respectively, reported pain relief. Mean pain relief length after 15 minutes for type 1 distribution was 60 mm; for type 2, 44 mm; and for type 3, 22 mm; and after 2 weeks, it was 34 mm for type 1, 31 mm for type 2, and 57 mm for type 3. There was no correlation between early and late response. Pain during intervention was less pronounced in type 2 injection, compared with type 1 (P = .002). On the basis of anatomic sections, type 1 injection was intraepineural; type 2, extraepineural; and type 3, paraneural.

CONCLUSION

Therapeutic SNRB is effective in sciatica, but early response does not predict the effect after 2 weeks. Type 1 injections are more painful than type 2 injections.

Magnetic resonance classification of lumbar intervertebral disc degeneration

STUDY DESIGN

A reliability study was conducted.

OBJECTIVES

To develop a classification system for lumbar disc degeneration based on routine magnetic resonance imaging, to investigate the applicability of a simple algorithm, and to assess the reliability of this classification system.

SUMMARY OF BACKGROUND DATA

A standardized nomenclature in the assessment of disc abnormalities is a prerequisite for a comparison of data from different investigations. The reliability of the assessment has a crucial influence on the validity of the data. Grading systems of disc degeneration based on state of the art magnetic resonance imaging and corresponding reproducibility studies currently are sparse.

METHODS

A grading system for lumbar disc degeneration was developed on the basis of the literature. An algorithm to assess the grading was developed and optimized by reviewing lumbar magnetic resonance examinations. The reliability of the algorithm in depicting intervertebral disc alterations was tested on the magnetic resonance images of 300 lumbar intervertebral discs in 60 patients (33 men and 27 women) with a mean age of 40 years (range, 10-83 years). All scans were analyzed independently by three observers. Intra- and interobserver reliabilities were assessed by calculating kappa statistics.

RESULTS

There were 14 Grade I, 82 Grade II, 72 Grade III, 68 Grade IV, and 64 Grade V discs. The kappa coefficients for intra- and interobserver agreement were substantial to excellent: intraobserver (kappa range, 0.84-0.90) and interobserver (kappa range, 0.69-0.81). Complete agreement was obtained, on the average, in 83.8% of all the discs. A difference of one grade occurred in 15.9% and a difference of two or more grades in 1.3% of all the cases.

CONCLUSION

Disc degeneration can be graded reliably on routine T2-weighted magnetic resonance images using the grading system and algorithm presented in this investigation.

Therapeutic efficacy of selective nerve root blocks in the treatment of lumbar radicular leg pain

The objective of this study was to investigate the clinical effectiveness of nerve root blocks (i.e., periradicular injection of bupivacaine and triamcinolone) for lumbar monoradiculopathy in patients with a mild neurological deficit. We have retrospectively analysed 30 patients (29-82 years) with a minor sensory/motor deficit and an unequivocal MRI finding (20 disc herniations, 10 foraminal stenoses) treated with a selective nerve root block. Based on the clinical and imaging findings, surgery (decompression of the nerve root) was justifiable in all cases. Twenty-six patients (87%) had rapid (1-4 days) and substantial regression of pain, five required a repeat injection. 60% of the patients with disc herniation or foraminal stenosis had permanent resolution of pain, so that an operation was avoided over an average of 16 months (6-23 months) follow-up. Nerve root blocks are very effective in the non-operative treatment of minor monoradiculopathy and should be recommended as the initial treatment of choice for this condition.

Therapeutic efficacy of selective nerve root blocks in the treatment of lumbar radicular leg pain

The objective of this study was to investigate the clinical effectiveness of nerve root blocks (i.e., periradicular injection of bupivacaine and triamcinolone) for lumbar monoradiculopathy in patients with a mild neurological deficit. We have retrospectively analysed 30 patients (29-82 years) with a minor sensory/motor deficit and an unequivocal MRI finding (20 disc herniations, 10 foraminal stenoses) treated with a selective nerve root block. Based on the clinical and imaging findings, surgery (decompression of the nerve root) was justifiable in all cases. Twenty-six patients (87%) had rapid (1-4 days) and substantial regression of pain, five required a repeat injection. 60% of the patients with disc herniation or foraminal stenosis had permanent resolution of pain, so that an operation was avoided over an average of 16 months (6-23 months) follow-up. Nerve root blocks are very effective in the non-operative treatment of minor monoradiculopathy and should be recommended as the initial treatment of choice for this condition.

Painful Lumbar Disk Derangement: Relevance of Endplate Abnormalities at MR Imaging

PURPOSE

To investigate the predictive value of magnetic resonance (MR) imaging of abnormalities of the lumbar intervertebral disks, particularly with adjacent endplate changes, to predict symptomatic disk derangement, with discography as the standard.

MATERIALS AND METHODS

Fifty patients aged 28-50 years with chronic low back pain and without radicular leg pain underwent prospective clinical examination and sagittal T1- and T2-weighted and transverse T2-weighted MR imaging. Subsequently, patients underwent lumbar discography with a pain provocation test (116 disks). MR images were evaluated for disk degeneration, a high-signal-intensity zone, and endplate abnormalities. Results of pain provocation at discography were rated independently of the image findings as concordant or as nonconcordant or painless. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated to assess the clinical relevance of MR abnormalities.

RESULTS

Normal disks on MR images were generally not painful at provocative discography (NPV, 98%). Disk degeneration (sensitivity, 98%; specificity, 59%; PPV, 63%) and a high-signal-intensity zone (sensitivity, 27%; specificity, 85%; PPV, 56%) were not helpful in the identification of symptomatic disk derangement. When only moderate and severe type I and type II endplate abnormalities were considered abnormal, all injected disks caused concordant pain with provocation (sensitivity, 38%; specificity, 100%; PPV, 100%).

CONCLUSION

Moderate and severe endplate abnormalities appear be useful in the prediction of painful disk derangement in patients with symptomatic low back pain.

Retroperitoneal endoscopically assisted minilaparotomy for anterior lumbar interbody fusion: technical feasibility and complications

STUDY DESIGN

Description of a novel less invasive technique and prospective evaluation of associated morbidity and potential complications.

OBJECTIVE

To investigate the feasibility of a novel endoscope-assisted retroperitoneal approach (REAM) for anterior lumbar interbody fusion (ALIF).

SUMMARY OF BACKGROUND DATA

Minimally and less invasive approaches are currently favored to perform ALIF. However, the present endoscopic techniques have not found widespread acceptance, because they are technically demanding, and microsurgical techniques are not time effective when two separate approaches are needed for L5-S1 (transperitoneal) and L4-L5 (retroperitoneal).

METHODS

The authors have developed the technique of REAM, which consists of three stages: 1) endoscopic retroperitoneal mobilization of the peritoneal sac, 2) midline minilaparotomy (4-6 cm), and 3) standard open anterior lumbar interbody fusion. Twenty patients were prospectively enrolled in this study and perioperative data (i.e., blood loss, operative time, intra- and postoperative complications) were collected to assess the feasibility of this approach.

RESULTS

Six single-level and 14 two-level ALIFs from L3-L4 to L5-S1 were performed with a mean operative time of 108 minutes (range, 85-150) and an average estimated blood loss of 200 mL (range, 50-500). The follow-up (range, 12-29 months) on 20 patients showed that there were no perioperative or postoperative complications related directly to this approach.

CONCLUSION

Anterior lumbar interbody fusion by REAM can be performed without additional hazard to the patient and appears to be a reasonable alternative to existing less invasive procedures.

MR morphology of alar ligaments and occipitoatlantoaxial joints: study in 50 asymptomatic subjects

PURPOSE

To assess the magnetic resonance (MR) imaging appearance of the alar ligaments and joints in the upper cervical spine to determine the prevalence of structural alterations in asymptomatic individuals.

MATERIALS AND METHODS

Fifty healthy individuals (31 men, 19 women) with a mean age of 30 years (range, 19-47 years) underwent coronal T1- and T2-weighted and transverse T1-weighted MR imaging. MR findings were analyzed independently by two musculoskeletal radiologists, with disagreements resolved in conference.

RESULTS

Alar ligaments were detected in 42 (84%) (left side) and 38 (76%) (right side) of 50 individuals. The majority of ligaments (88%) and joints (58%) of the craniocervical junction (CCJ) were asymmetric. Asymmetry of the joint between C1 and C2 was less frequent (46%). Small amounts of fluid were detected in 8% of CCJ joints and 56% of C1-C2 joints in asymptomatic individuals.

CONCLUSION

Asymmetry of alar ligaments, CCJ and C1-C2 facet joints, and joint effusions are common in asymptomatic individuals. The clinical relevance of these MR findings is therefore limited in the identification of the source of neck pain in symptomatic patients.

Subacute subdural haematoma complicating lumbar microdiscectomy

There have been no previous reports of a spinal subdural haematoma occurring as a complication of spinal surgery. We highlight the pitfalls in the diagnosis and management of a subacute subdural haematoma resulting from a dural tear which occurred as a surgical complication of microdiscectomy.

Natural history of individuals with asymptomatic disc abnormalities in magnetic resonance imaging: predictors of low back pain-related medical consultation and work incapacity

STUDY DESIGN

Prospective study on individuals with asymptomatic lumbar disc abnormalities detected in magnetic resonance imaging.

OBJECTIVES

To determine the natural history of asymptomatic disc abnormalities in magnetic resonance imaging and to identify predictors of future low back pain-related medical consultation and work incapacity.

SUMMARY OF BACKGROUND DATA

The natural history of individuals with asymptomatic disc herniations has not been well established, but the high rate of lumbar disc alterations recently detected in asymptomatic individuals by magnetic resonance imaging demands reconsideration of a pathomorphology-based explanation of low back pain and sciatica.

METHODS

Forty-six asymptomatic individuals who had a high rate of disc herniations (73%) were observed for an average of 5 years (range, 54-72 months). Four classes of variables (medical data including magnetic resonance imaging-identified disc abnormalities, general psychological factors, physical job characteristics, and psychosocial aspects of work) were assessed at baseline and follow-up.

RESULTS

Disc herniations and neural compromise did not significantly worsen at follow-up, whereas disc degeneration progressed in 17 individuals (41.5%). Minor episodes of low back pain occurred in 19 individuals (41.3%), 6 of whom had to seek medical treatment and 5 of whom had to stop work temporarily. The requirement for low back pain-related medical consultation was predicted with high accuracy by listlessness, job satisfaction, and working in shifts (P < 0.001). Work incapacity was best predicted by physical job characteristics, job disaffection, and working in shifts (P < 0.01).

CONCLUSION

Physical job characteristics and psychological aspects of work were more powerful than magnetic resonance imaging-identified disc abnormalities in predicting the need for low back pain-related medical consultation and the resultant work incapacity. However,the conclusions are still preliminary, and replication of the findings in larger and more representative study samples is needed.

[Acute myelopathy and cauda equina syndrome]

The high incidence of non-specific, benign back trouble often delays the diagnosis of specific causes of back pain and thus result in neurological deficits. Degenerative abnormalities in the cervical spine may narrow the spinal canal and result in acute myelopathy subsequent to minor injuries. Large cervical or lumbar disc herniations causing myelon, conus or cauda equina compression are rare but must not be overlooked. Spinal metastases may remain unrecognised for a long period and lead to the correct diagnosis only after presentation with neurological deficits. Acute myelopathy or cauda equina syndrome are indications for immediate diagnostic assessment and treatment in a spine centre.

Functional MR imaging of the craniocervical junction. Correlation with alar ligaments and occipito-atlantoaxial joint morphology: a study in 50 asymptomatic subjects

PURPOSE

Whiplash injuries are frequent in industrialized countries. The acute and chronic symptoms following such injuries are incompletely understood and objective clinical or imaging findings are rare. Several authors have suspected that rear end collisions occurring when the head is rotated may result in tears of the alar ligaments. There has been experimental proof that a torn alar ligament increases the rotation of the C0/C1 and C1/C2 segments to the contralateral side. Functional cross sectional imaging has therefore been proposed to diagnose injuries of the alar ligaments. So far, published data on normal ranges of rotation in an asymptomatic population have been sparse. The aim of this study was to determine by MR imaging the normal range of rotation in the first three cervical segments and their relation to the morphology of the alar ligaments and the occipito-atlantoaxial joints.

MATERIAL AND METHODS

Functional MR imaging of the craniocervical junction in maximum active left and right head rotation was performed in 50 healthy volunteers with a mean age of 29.8 years (31 men, 19 women, range 19-47 years). Measurements were independently performed by two musculoskeletal radiologists to assess interobserver error. The results were correlated with gender and age, with morphological findings in the occipito-atlantoaxial joints (i.e. joint symmetry, joint effusions, dens position), and with the form, course and symmetry of the alar ligaments.

RESULTS

The mean range of rotation for the C0/C1 joint was 2.7 degrees (standard deviation [SD] 3.3 degrees)/3.3 degrees (SD 3.6 degrees) (right/left) and at the C1/C2 level 38 degrees (SD 6.5 degrees)/37.8 degrees (SD 6.4 degrees). The mean differences in left/right rotation were: C0/C1 3.5 degrees (SD 2.8 degrees) and C1/C2 6.3 degrees (SD 4.4 degrees). No correlation was found between segmental rotation and morphological characteristics of the craniocervical joints or ligament structures.

CONCLUSION

There is wide variation of segmental motion in the upper cervical spine. Differences in right-to-left rotation are frequently encountered in an asymptomatic population. Therefore, these measurements are unsuitable for indirect diagnosis of soft tissue lesions after whiplash injury and should not be used as a basis for treatment guidelines.

Positional MR imaging of the lumbar spine: does it demonstrate nerve root compromise not visible at conventional MR imaging?

PURPOSE

To evaluate whether positional magnetic resonance (MR) images of the lumbar spine demonstrate nerve root compromise not visible on MR images obtained with the patient in a supine position (conventional MR images).

MATERIALS AND METHODS

Thirty patients with chronic low back pain unresponsive to nonsurgical treatment and with disk abnormalities but without compression of neural structures were included. Positional MR images were obtained by using an open-configuration, 0.5-T MR imager with the patients seated and with flexion and extension of their backs. The disk and nerve root were related to the body position. Nerve root compression and foraminal size were correlated with the patient's symptoms, as assessed with a visual analogue scale.

RESULTS

Nerve root contact without deviation was present in 34 of 152 instances in the supine position, in 62 instances in the seated flexion position, and in 45 instances in the seated extension position. As compared with the supine position, in the seated flexion position nerve root deviation decreased from 10 to eight instances; in the seated extension position, it increased from 10 to 13 instances. Nerve root compression was seen in one patient in the seated extension position. Positional pain score differences were significantly related to changes in foraminal size (P =.046) but not to differences in nerve root compromise.

CONCLUSION

Positional MR imaging more frequently demonstrates minor neural compromise than does conventional MR imaging. Positional pain differences are related to position-dependent changes in foraminal size.

Spondylodiscitis caused by viridans streptococci: three cases and a review of the literature

Three cases of spondylodiscitis caused by viridans streptococci were observed within the course of 1 month. Although streptococci have been reported as the third most frequent cause of spondylodiscitis after staphylococci and gram-negative bacteria, alpha-haemolytic streptococci are rarely seen. The three patients presented with symptoms of low back pain; they felt well and did not have a fever or chills. Laboratory examinations revealed inflammation. Further examinations such as scintigraphy, computed tomography or magnetic resonance imaging were done. Bacteriological diagnosis was established by blood cultures in two cases and by needle biopsy of the disco-vertebral space in one. In one patient endocarditis was also documented. Because the prevalence of endocarditis was found to be higher in our cases of spondylodiscitis due to Streptococcus viridans than for other bacteria, the exclusion of this diagnosis must be pursued aggressively. These observations lead us to question if the spectrum of bacteria causing spondylodiscitis is undergoing a change. an aetiological agent could be isolated in 1168 patients (85.4%): in 48% a staphylococcus, in 28% a gram-negative bacterium and in only 10% a streptococcus. There were two cases of viridans streptococci (0.2%). These two cases together with other single case reports [14-22] account for 15 cases of spondylodiscitis due to alpha-haemolytic streptococci. Differentiation of the organisms to the species level was accomplished in six cases: S. mitis (3), S. sanguis (2) and S. anginosus (1). Although a multitude of organisms, bacterial as well as fungal, causing spondylodiscitis has been reported in recent years, almost all were single cases [23-42]. The unusual observation of three cases of spondylodiscitis due to alpha-haemolytic streptococci within 1 month prompted us to review the clinical and laboratory findings and to compare these cases with those caused by Staphylococcus aureus.

Immunohistochemical analysis of type-X-collagen expression in osteoarthritis of the hip joint

Conflicting data have been reported on the spatial distribution of type X-collagen expression in osteoarthritis, and no concise data exist on a possible correlation between type X-collagen expression and clinical and radiological alterations. Well defined clinical and radiological data were compared with histopathological and immunohistochemical findings to investigate the expression of type-X collagen in osteoarthritis of the hip joint. Femoral heads were obtained in toto from 11 patients undergoing routine hip arthroplasty for femoral neck fractures (n = 3) or osteoarthritis (n = 8) and from 13 patients (age: 12 days to 69 years) without any evidence of hip-joint pathology. Whole coronal sections from the femoral head were decalcified for routine histology and immunohistochemical analysis with use of type-specific monoclonal antibodies to type-X collagen. Our results demonstrate that type-X collagen is consistently found in osteoarthritic cartilage and is absent from normal adult cartilage (including the region of calcified cartilage). Except for the occurrence of type-X collagen in the middle zone of articular cartilage in advanced stages of osteoarthritis, there is no specific change in the staining pattern or intensity for the collagen during osteoarthritis, particularly when the staining is related to clinical and radiological parameters. Hardly more than 20% of the extracellular matrix stained for type-X collagen; therefore, we suggest that, in most cases, this type of collagen may not play a direct biomechanical role in the weakening of osteoarthritic cartilage but rather may contribute indirectly to a disturbance of the disc biomechanics by altering matrix-molecule interaction. However, expression of type-X collagen may indicate a change in chondrocyte phenotype that consistently coincides with the formation of chondrocyte clusters, one of the first alterations in osteoarthritis visible on histologic examination.

Anterior cervical interbody fusion with plate fixation for chronic spondylotic radiculopathy: a 2- to 8-year follow-up

In retrospectively analyzing 35 consecutive patients with chronic spondylotic radiculopathy treated by nerve root decompression, interbody fusion (Robinson technique), and plating, we studied the perioperative complication rate as well as the long-term clinical and radiologic outcomes of an additional plate fixation in degenerative cervical disorders. After an average of 54 months (range 24-102 months), all cases were reviewed for the purpose of this study. There were no perioperative or postoperative complications related to the plate fixation. In particular, there was no infection, graft extrusion, or neurologic deterioration. A solid fusion was obtained in all cases with a single-level fusion and in 87% of the cases with a multilevel fusion. The overall fusion rate was 94%. The clinical outcome of the patients with chronic radiculopathy was comparable with that in the literature, with only three patients (8.6%) having a poor result. This study demonstrated that plate fixation can be a useful adjunct in patients undergoing interbody fusion for cervical spondylotic radiculopathy. Plate fixation seems to reduce the rate of nonunion without additional hazards for the patient. This report should form the basis for a prospective randomized trial to answer the question more conclusively of whether an additional plate fixation is superior to uninstrumented cervical fusion in degenerative disorders.

Chondromyxoid fibroma of two thoracic vertebrae

We report on a case of chondromyxoid fibroma involving two adjacent thoracic vertebrae with features of aggressive behaviour on radiographs, CT and MRI. Histology revealed typical chondromyxoid fibroma with unusually coarse calcifications. Chondromyxoid fibroma of the spine is rare, and only 30 of these tumours have been reported so far. Involvement of two contiguous vertebral bodies by chondromyxoid fibroma, as reported here, appears exceptional.

MR imaging and CT in osteoarthritis of the lumbar facet joints

OBJECTIVE

To test the agreement between MR imaging and CT in the assessment of osteoarthritis of the lumbar facet joints, and thus to provide data about the need for an additional CT scan in the presence of an MR examination.

DESIGN AND PATIENTS

Using a four-point scale, two musculoskeletal radiologists independently graded the severity of osteoarthritis of 308 lumbar facet joints on axial T2-weighted and on sagittal T1- and T2-weighted turbo-spin-echo images and separately on the corresponding axial CT scans. Kappa statistics and percentage agreement were calculated.

RESULTS

The weighted kappa coefficients for MR imaging versus CT were 0.61 and 0.49 for readers 1 and 2, respectively. The weighted kappa coefficients for interobserver agreement were 0.41 for MR imaging and 0.60 for CT, respectively. There was agreement within one grade between MR and CT images in 95% of cases for reader 1, and in 97% of cases for reader 2.

CONCLUSION

With regard to osteoarthritis of the lumbar facet joints there is moderate to good agreement between MR imaging and CT. When differences of one grade are disregarded agreement is even excellent. Therefore, in the presence of an MR examination CT is not required for the assessment of facet joint degeneration.

The impact of clinical, morphological, psychosocial and work-related factors on the outcome of lumbar discectomy

In a prospective controlled trial on 46 patients undergoing lumbar discectomy, three classes of variables (medical data including MRI-identified morphological abnormalities, general psychological factors and psychosocial aspects of work) were analyzed with regard to their predictive value for the outcome of lumbar disc surgery at 2 year follow-up. Multiple regression analyses were used to identify the best predictor variables of four different outcome measures (i.e. pain relief, reduction of disability in daily activities, return to work and surgical outcome). MRI-identified nerve root compromise and social support from the spouse were independent predictors of pain relief 2 years after surgery (R2 = 0.40, P < 0.01). Return to work 2 years after surgery was best predicted by depression and occupational mental stress (R2 = 0.36, P < 0.001). MRI-identified extent of herniation and depression were significant predictors of a good surgical outcome after lumbar discectomy (R2 = 0.61, P < 0.001). This study has demonstrated that the outcome of discectomy is critically dependent on which outcome variables are selected and that different sorts of predictor variables have a distinct influence on the various outcome variables. Obvious morphological alterations (i.e. disc extrusions, nerve root compromise) proved to be significant predictors of postoperative pain relief and improvement of disability in daily activities justifying a surgical treatment approach in these cases. The most important finding of this study was that return to work was not influenced by any clinical findings or MR-identified morphological alterations, but solely by psychological factors (i.e. depression) and psychological aspects of work (i.e. occupational mental stress).

[Diagnostic assessment in lumbar back pain. I. Anamnesis and clinical examination]

The diagnostic assessment of the low back pain patient is often unsatisfactory because a clear morphological alteration explaining the patient's symptoms can only be found in 10-20% of the cases. The majority of the patients is suffering from non-specific low back pain. However, the high incidence of benign, self-limiting low back pain leads to the risk of overlooking specific causes such as tumor or infection. Similarly, relevant paresis and bladder and bowel dysfunction must be diagnosed in time. Furthermore, the aim of the diagnostic work-up is to diagnose and treat specific causes of back and leg pain (e.g. disc herniation and spinal stenosis) to avoid chronicity. In the majority of the cases, history and clinical examination alone allow to differentiate between specific and non-specific low back pain and may lead to a further diagnostic work-up by imaging studies.

[Diagnostic assessment in lumbar back pain. II. Imaging and image-guided infiltrations]

The diagnostic assessment of low back pain should predominantly be based on history and clinical examination rather than on imaging studies. The problem of diagnostic imaging in low back pain is related to the high rate of asymptomatic morphological alterations in the lumbar spine. The diagnosis should therefore not be guided by findings in imaging. The imaging studies (standard radiographs and MRI) should verify the clinically suspected diagnosis and further lead to imaging guided injection studies (e.g. nerve root block, facet joint block, sacro-iliac joint block, provocative discography) to differentiate between symptomatic and asymptomatic morphological alterations. With longlasting local anaesthetics and steroids it is possible to achieve a diagnostic as well as a therapeutic effect.

MR imaging of the lumbar spine: prevalence of intervertebral disk extrusion and sequestration, nerve root compression, end plate abnormalities, and osteoarthritis of the facet joints in asymptomatic volunteers

PURPOSE

To identify the magnetic resonance (MR) abnormalities of the lumbar spine that have a low prevalence in asymptomatic patients and thus determine the findings that are predictive of low back pain in symptomatic patients.

MATERIALS AND METHODS

Sagittal T1-weighted and sagittal and axial T2-weighted MR images were obtained in 60 asymptomatic volunteers aged 20-50 years. The MR images were evaluated with regard to intervertebral disk abnormalities, end plate abnormalities, and osteoarthritis of the facet joints by two musculoskeletal radiologists independently.

RESULTS

Disk bulging or disk protrusion was found in 42 (14%) and 48 (16%) of the intervertebral spaces in 37 (62%) and 40 (67%) subjects, respectively. High-signal-intensity zones were found commonly (in 23 [7.7%] and 25 [8.3%] of the intervertebral spaces in 19 (32%) and 20 (33%) subjects, respectively). Disk extrusions were less common (in 11 [3.7%] and 11 [3.7%] of the intervertebral spaces in 11 (18%) and 11 (18%) subjects, respectively). There were no disk sequestrations. A nerve root compression in a single intervertebral space was diagnosed by one reader. End plate abnormalities were found in two (0.7%) and six (1.9%) of the intervertebral spaces in two (3%) and six (10%) subjects, respectively. No severe osteoarthritis was diagnosed by either reader.

CONCLUSION

In patients younger than 50 years, disk extrusion and sequestration, nerve root compression, end plate abnormalities, and osteoarthritis of the facet joints are rare and, therefore, may be predictive of low back pain in symptomatic patients.

Progressive thrombotic occlusion of the left common iliac artery after anterior lumbar interbody fusion

We report a case of progressive thrombotic occlusion of the left common iliac artery in a 41-year-old woman after anterior interbody fusion, which initially presented only as a sensation of numbness. Diagnosis was delayed until complete arterial occlusion occurred 36 h after surgery. A sensory deficit may be the only early sign of a progressive thrombotic arterial occlusion. In anterior spinal surgery, routine postoperative vascular monitoring of the lower extremities is recommended and mandatory for early diagnosis and treatment of this rare complication.

What help and what confusion can imaging provide?

Low back pain is a very common but benign and, in general, self-limiting disease indicating that only a small proportion of patients will require sophisticated imaging studies. Recent studies have highlighted the fact that a simple relationship of structural abnormalities to low back pain is impossible because similar alterations can be found in symptomatic as well as in asymptomatic individuals. these findings question our current criteria for the diagnosis of low back pain disorders with regard to their discriminative power in differentiating diseased and non-diseased individuals. Structural abnormalities demonstrated by imaging studies should therefore only be interpreted in the light of the clinical findings. This review shows that only a few studies contribute to our understanding of the clinical efficacy of imaging studies in the evaluation of low back pain disorders. There is an absolute need for comprehensive, well conducted studies on the impact of specific imaging modalities on diagnosis and treatment of lumbar spinal disease.

Immunolocalization of major interstitial collagen types in human lumbar intervertebral discs of various ages

We used complete transverse sections through 65 samples of human lumbar intervertebral discs for immunolocalization of the major interstitial collagen types I, II, III, V, VI and IX. The samples were selected from 47 patients ranging in age from 0 (fetuses) to 86 years. The results were compared with the histological findings in disc tissue degeneration and/or reparative alterations as indicated by tear and cleft formation, chondrocyte proliferation, mucous degeneration, granular matrix changes and fibrocartilage fibrillation. We observed a typical pattern for each antibody and each anatomical structure, with, however, remarkable inter- and intraindividual variability, which could be monitored only by use of the complete transverse sections. Accordingly, collagen I was seen in the normal annulus fibrosus and in the degeneratively altered nucleus pulposus, but not within the end-plate, regardless of degenerative changes. Collagens II and IX were found in the normal nucleus pulposus, the inner annulus fibrosus and the end-plate. The collagen II (and IX) staining seemed to be enhanced in areas of minor degenerative lesions, but reduced in advanced lesions and in the degenerated end-plate. Collagens III and VI were significantly increased in areas of minor to advanced degeneration in all anatomical settings, while collagen V showed only minor changes in its staining pattern. In general, histological signs of tissue degeneration coincided with significant quantitative, but also with certain qualitative, changes in the composition of the collagenous disc matrix. These observations indicate the association of degenerative and/or reparative alterations of the intervertebral disc and changes in the collagenous matrix, but document the variability in the extent of the abnormalities observed.

1997 Volvo Award winner in basic science studies. Immunohistologic markers for age-related changes of human lumbar intervertebral discs

STUDY DESIGN

The authors performed a correlative macroscopic, histologic, and immunohistochemical investigation on human lumbar intervertebral discs using complete motion segment slices, including all age groups and stages of degeneration.

OBJECTIVES

To identify markers for age-related changes of human lumbar intervertebral discs. In particular, to investigate changes in the distribution pattern of collagen Types I, II, III, IV, V, VI, IX, and X. In addition, to study posttranslational protein modification by the immunolocalization of N-(carboxylmethyl)lysine (CML), which is regarded as a biomarker for oxidative stress.

SUMMARY OF BACKGROUND DATA

Data on a correlation of age-related changes in disc morphology and disc matrix composition is sparse. So far, no comprehensive analysis considered a correlation of macroscopic, histologic, and biochemical age-related alterations using complete sections of intervertebral discs (i.e., including nucleus pulposus, anulus fibrosus, endplates, and vertebral bodies). In addition, there is need for specific markers for these disc changes to allow for a better correlation with disc function.

METHODS

After photodocumentation of the macroscopic appearance, 229 sagittal lumbar motion segments obtained from 47 individuals (fetal to 86 years) during routine autopsy were processed for histologic and immunohistochemical analysis. All slices were investigated for histologic alterations of disc degeneration. A randomly selected subset of these specimens (n = 45) was used for a correlative analysis of interstitial collagens and molecular modifications of matrix proteins.

RESULTS

The presence of CML-modification of extracellular matrix proteins, mainly collagen, was observed first in the nucleus pulposus of a 13-year-old individual and increased significantly with age. In elderly people, both the nucleus pulposus and the anulus fibrosus showed extensive CML deposition. This CML deposition was accentuated in areas of macroscopic and histologic disc degeneration. After the occurrence of CML in the nucleus pulposus, we found a change in the collagen type pattern. An initial increase in nuclear collagen Types II, III, and VI staining was followed by a loss of collagen Type II, the occurrence of collagen Type I, and the persistence of high collagen Type III and VI levels, which were finally decreased again. The nuclear chondrocytes revealed significant changes in their immediate pericellular matrix, indicating phenotypic changes. Thus, exclusively in the nucleus pulposus of adolescents and young adults a significant proportion of cells positively stained for the basement membrane collagen Type IV. Collagen Type X was expressed by nuclear chondrocytes at a higher age and was associated with advanced degenerative disc alterations.

CONCLUSIONS

The authors present the first study in which age-related changes are correlated on a macroscopic, histologic, and molecular level using complete sections of lumbar motion segments. They reconfirm the notion that disc degeneration starts as early as in the second decade of life. Therefore, only early prevention of disc damage may inhibit disc degeneration and its sequelae. Phenotypic alterations of nuclear chondrocytes as monitored by collagen Type IV in young adults with minor lesions and collagen Type X in advanced lesions indicate distinct cellular reactions, possibly as a reaction to enhanced oxidative stress. The degree of this oxidative stress is reflected by the CML-staining pattern which, in turn, indicates that the disc undergoes an accumulative stress, possibly leading to altered properties of the collagen fibrils and, thereby, tissue destruction. The deposition of CML proved to be the best marker for ongoing age-related changes in the intervertebral disc.

Immunolocalization of type X collagen in human lumbar intervertebral discs during ageing and degeneration

Type X collagen has so far not been reported to occur in human intervertebral discs. The objective of this study was therefore to investigate the occurrence of type X collagen in human lumbar intervertebral discs during ageing and degeneration. Ninety intervertebral discs with adjacent endplates were excised in toto from individuals (0-86 years) without known spinal disease and were processed for routine decalcified histology. Appropriate slices of each disc were processed for immunohistochemistry using a type-specific, monoclonal antibody raised against human type X collagen. Each intervertebral disc was examined for macroscopic and histomorphological features of disc degeneration. Immunohistochemically, a positive specific type X staining was observed in the hypertrophic zone of the growth plate and only in the interstitial matrix of juvenile (<2 years) nucleus pulposus. In adult discs, type X collagen could be localized in conjunction with advanced disc degeneration and first occurred in the disc matrix (i.e., pericellular region) of a 47-year-old specimen. Positive type X staining of the disc matrix was more frequently found in senile (>70 years) discs with end stages of disc degeneration. This study provides the first evidence for the occurrence of type X collagen in human lumbar intervertebral discs and it appears that type X collagen is re-expressed in late stages of disc degeneration.

Real-time control for transscleral cyclophotocoagulation

BACKGROUND

In transscleral cyclophotocoagulation, the surgeon cannot directly observe the applied laser effects. Overdosage, possibly resulting in unwanted pop effects, or underdosage with no therapeutic effect therefore often occur.

METHOD AND MATERIALS

Laser radiation passing through the sclera and ciliary body is partly reflected from the fundus and can be monitored from outside the eye by a detector system. Since all other parameters influencing the intensity of the recorded radiation are constant in time during one laser exposure, the time dependence of this radiation directly reflects the change of transmission of the treated tissue. The laser exposure therefore can be stopped by a computer when certain criteria of the recorded curves are fulfilled. In addition, the transmission curves are displayed on a monitor in real time, permitting the surgeon to interrupt the exposure. A Nd:YAG laser and a diode laser are connected to the device. After successful tests in enucleated porcine eyes which were evaluated histologically and in human cadaver eyes this method is applied to patients suffering from refractory glaucoma.

RESULTS

The transmission curves from enucleated porcine eyes show that the 810-nm diode laser is more appropriate for this method than the 1064-nm. Nd:YAG laser, because the radiation output of the diode is more stable in time and the tissue absorption is higher, both resulting in a larger dynamical range of useful signal. The curves from the porcine eyes, the human cadaver eyes and the curves from patients show a typical shape which allows interruption of exposure either by the surgeon or by the computer program before a pop effect occurs.

CONCLUSIONS

This new method increases the precision and safety of transscleral cyclophotocoagulation.

Solitary plasma-cell myeloma of the spine in an adolescent. Case report of an unusual presentation

We report an unusual presentation of a solitary plasma-cell myeloma of the spine in an adolescent patient. Our case indicates the need to consider plasma-cell myeloma as a differential diagnosis even in younger patients.

TOTAL HIP ARTHROPLASTY AFTER PREVIOUS PROXIMAL FEMORAL OSTEOTOMY

We compared 74 total hip arthroplasties (THAs) carried out after previous proximal femoral osteotomy with a diagnosis-matched control group of 74 primary procedures performed during the same period. We report the perioperative results and the clinical and radiological outcome at five to ten years.

We anticipated a higher rate of complications in the group with previous osteotomy, but found no significant difference in the rate of perioperative complications (11% each) or in the septic (8% v 3%) and aseptic (4% each) revision rates. There was a trend towards improved survival in the group without previous osteotomy (90% v 82%), but this difference was not statistically significant. The only significant differences were a higher rate of trochanteric osteotomy (88% v 14%) and a longer operating time in the osteotomy group.

Our study indicates that THA after previous osteotomy is technically more demanding but not necessarily associated with a higher rate of complications. Furthermore, proximal femoral osteotomy does not jeopardise the clinical and radiological outcome of future THA enough to exclude the use of osteotomy as a therapeutic alternative in younger patients.

Total hip arthroplasty after previous proximal femoral osteotomy

We compared 74 total hip arthroplasties (THAs) carried out after previous proximal femoral osteotomy with a diagnosis-matched control group of 74 primary procedures performed during the same period. We report the perioperative results and the clinical and radiological outcome at five to ten years. We anticipated a higher rate of complications in the group with previous osteotomy, but found no significant difference in the rate of perioperative complications (11% each) or in the septic (8% v 3%) and aseptic (4% each) revision rates. There was a trend towards improved survival in the group without previous osteotomy (90% v 82%), but this difference was not statistically significant. The only significant differences were a higher rate of trochanteric osteotomy (88% v 14%) and a longer operating time in the osteotomy group. Our study indicates that THA after previous osteotomy is technically more demanding but not necessarily associated with a higher rate of complications. Furthermore, proximal femoral osteotomy does not jeopardize the clinical and radiological outcome of future THA enough to exclude the use of osteotomy as a therapeutic alternative in younger patients.

Atlanto-axial dislocation without fracture: case report of an ejection injury

We describe an unusual injury to the upper cervical spine sustained during ejection from an aircraft. MRI provided an accurate and direct diagnosis of the severe ligamentous injuries.

Pedicle screw fixation in spinal disorders: a European view

Continuing controversy over the use of pedicular fixation in the United States is promoted by the lack of governmental approval for the marketing of these devices due to safety and efficacy concerns. These implants have meanwhile become an invaluable part of spinal instrumentation in Europe. With regard to the North American view, there is a lack of comprehensive reviews that consider the historical evolution of pedicle screw systems, the rationales for their application, and the clinical outcome from a European perspective. This literature review suggests that pedicular fixation is a relatively safe procedure and is not associated with a significantly higher complication risk than non-pedicular instrumentation. Pedicle screw fixation provides short, rigid segmental stabilization that allows preservation of motion segments and stabilization of the spine in the absence of intact posterior elements, which is not possible with non-pedicular instrumentation. Fusion rates and clinical outcome in the treatment of thoracolumbar fractures appear to be superior to that achieved using other forms of treatment. For the correction of spinal deformity (i.e., scoliosis, kyphosis, spondylolisthesis, tumor), pedicular fixation provides the theoretical benefit of rigid segmental fixation and of facilitated deformity correction by a posterior approach, but the clinical relevance so far remains unknown. In low-back pain disorders, a literature analysis of 5,600 cases of lumbar fusion with different techniques reveals a trend that pedicle screw fixation enhances the fusion rate but not clinical outcome. The most striking finding in the literature is the large range in the radiological and clinical results. For every single fusion technique poor and excellent results have been described. This review argues that European spine surgeons should begin to back up the evident benefits of pedicle screw systems for specific spinal disorders by controlled prospective clinical trials. This may prevent forthcoming medical licensing authorities from restricting the use of pedicle screw devices and dictating the practice of spinal surgery in Europe in the near future.

Tissue characterization of symptomatic and asymptomatic disc herniations by quantitative magnetic resonance imaging

The purpose of this investigation was to determine differences in tissue composition of symptomatic and asymptomatic disc herniations as reflected in T1 and T2 relaxation times (quantitative magnetic resonance imaging). Thirty patients with sciatica severe enough to require a discectomy and 46 asymptomatic volunteers (controls) were included in this study. Both groups had a clinical examination as well as a magnetic resonance investigation of the lumbar spine. The longitudinal and transverse magnetic relaxation times (T1 and T2, respectively) were calculated from a set of 20 images obtained with five single-slice/multi-echo sequences at different repetition time values on a commercial whole-body system (1.5 T). Twenty-two symptomatic and asymptomatic disc herniations could be matched according to age, gender, disc level, and the extent of herniation (protrusion or extrusion) and were compared with regard to T1 and T2 relaxation times. Symptomatic disc herniations exhibited significantly (pT1 < 0.04 and pT2 < 0.003) shorter T1 (delta T1: -182.1 milliseconds, -15%) and T2 (delta T2: -11.0 milliseconds, -21%) relaxation times than matched asymptomatic herniations. Symptomatic disc herniations also exhibited more advanced disc degeneration as graded by Pearce's criteria (p < 0.01). These results suggest that symptomatic and morphologically matched asymptomatic disc herniations differ with regard to disc matrix composition.

A new magnetic resonance imaging analysis method for the measurement of disc height variations

STUDY DESIGN

A new magnetic resonance image analysis method is proposed which is based on the definition of the borders of the vertebral bodies adjacent to the intervertebral disc and their varying relationships. The reproducibility of this method (the so-called "centroid" method) was assessed by consecutive measurements. Its potential to depict diurnal disc height variations was studied using randomized groups of volunteers.

OBJECTIVE

To determine if magnetic resonance imaging can reliably measure disc height variations in the lumbar spine in vivo.

SUMMARY OF BACKGROUND DATA

A review of the literature indicates that noninvasive, accurate methods to study the effect of load on intervertebral discs in vivo are needed.

METHODS

The reproducibility of the centroid method was assessed in 10 healthy volunteers in 2 consecutive measurements and compared to a conventional method (mean anterior and posterior disc height). To investigate the potential for the depiction of diurnal disc height variations, 10 volunteers were randomized in a study group (1 measurement in the morning, 1 measurement in the evening) and a control group (2 consecutive measurements in the morning).

RESULTS

The centroid method allows the depiction of disc height variations as small as 0.85 mm with a 95% confidence (tolerance limits), whereas a conventional method needs variations of at least 1.66 mm. In the study (diurnal) group, the disc height decreased significantly (P < 0.0001) during the day (mean, -0.9 mm), while no variation (P < 0.8) was found in the control group.

CONCLUSIONS

These results indicate that the centroid method can reliably detect disc height variations in an experimental setting. The centroid method provides the potential for evaluations of the effects of various work places, work equipment, work tasks, and postures.

Clinical efficacy of imaging modalities in the diagnosis of low-back pain disorders

This review provides methodological background and some guidelines for the evaluation of imaging modalities for the lumbar spine and reviews the current literature on the basis of different levels of efficacy which consider standards beyond technical quality or diagnostic accuracy. From a MEDLINE search, 672 articles (1985-1995) were retrieved which focused on the development or application of imaging modalities for lumbar spinal disorders. The papers were categorized according to different efficacy levels at which the imaging modalities were assessed. This review has demonstrated that the vast majority of reports evaluate imaging studies for the lumbar spine only at the technical efficacy level. A minor proportion of the articles focus on the evaluation at the level of diagnostic accuracy. Articles which assess imaging studies on a higher level of efficacy (e.g., diagnostic and therapeutic impact, patient outcome and cost-benefit analysis) are sparse. This review has outlined frequent methodological flaws in patient selection and design of imaging studies for the lumbar spine. The spine specialist should therefore become very critical in the interpretation of those studies and pay attention to patient selection and spectrum, choice of the reference standard, sample size, various forms of biases, and the reasoning behind clinical recommendations in order to improve his patient care.

1995 Volvo Award in clinical sciences. The diagnostic accuracy of magnetic resonance imaging, work perception, and psychosocial factors in identifying symptomatic disc herniations

STUDY DESIGN

This was a prospective study of patients (study group) with symptomatic disc herniations and asymptomatic volunteers (control group) matched for age, sex, and work-related risk factors.

OBJECTIVE

To determine the prevalence of disc herniation in a matched group of asymptomatic volunteers and to access the diagnostic accuracy of magnetic resonance imaging, work perception, and psychosocial factors in identifying symptomatic disc herniations.

SUMMARY OF BACKGROUND DATA

Disc herniations have been reported to occur in 20-36% of asymptomatic volunteers. A valid comparison of asymptomatic individuals and patients with disc herniations has not been performed.

METHODS

Forty-six patients with low back pain and sciatica severe enough to require a discectomy were compared with 46 age-, sex-, and risk factor-matched (heavy lifting, twisting and bending, vibration, and sedentary activity) asymptomatic volunteers. Both groups had a complete clinical and magnetic resonance imaging examination and completed a questionnaire to assess differences in the psychosocial and work perception profiles. The prevalence and the severity of morphologic alterations (disc herniation, disc degeneration, and neural compromise) was analyzed by tow independent radiologists in a blinded fashion. Differences between both groups regarding MRI findings, work perception (occupational mental stress, intensity of concentration, job satisfaction, and job-related resignation) and psychosocial factors (anxiety, depression, self-control, social support, and marital status) were compared using multivariate techniques. Stepwise discriminating analysis was used to identify the best discriminating variables within the magnetic resonance image, work perception, and psychosocial categories in terms of the diagnostic accuracy to predict group membership (study [pain] or control [no pain] group).

RESULTS

Matched controls had significantly more risk factors than a group of normal individuals. The present study has presented evidence that an age-, gender-, and occupational risk factors-matched group of asymptomatic patients shows a high incidence rate of disc herniations (76%). Although significantly less than the symptomatic group incidence of 96%, this represents a much higher prevalence rate than generally expected and reported in other studies of unmatched asymptomatic volunteers. Patients had more severe disc herniations (disc extrusions) than asymptomatic volunteers (35% vs. 13%). There was no significant differences regarding disc degeneration between both groups (96% vs. 85%). The only substantial morphologic difference between both groups was the presence of a neural compromise (83% vs. 22%), which was highly significant (P < 0.0001). There were significant differences between both groups regarding work perception (occupational mental stress, intensity of concentration, job satisfaction, and resignation; P < 0.027) and psychosocial factors (anxiety, depression, self-control, marital status; P < 0.0001). The best single predictor of a group membership was the extent of neural compromise. A combination of this factor with occupational mental stress, depression, and marital status was the best predictive model. With this model, the false-negative rate (potential overtreatment of disc morphology) was reduced by more than half compared with morphologic factors (nerve root compression) alone (22% vs. 11%).

CONCLUSIONS

In an age-, sex-, and risk factor-matched group of asymptomatic individuals, disc herniation had a substantially higher prevalence (76%) than previously reported in an unmatched group. Individuals with minor disc herniations (i.e., protrusion, contained discs) are at a very high risk that their magnetic resonance images are not a causal explanation of pain because a high rate of asymptomatic subjects (63%) had comparable morphologic findings. The only highly significant difference between the study group and control group regarding morphologic fi

Quantitative magnetic resonance imaging of the lumbar spine. Potential for investigations of water content and biochemical composition

Quantitative magnetic resonance imaging (relaxation time and proton density measurements) has gained increasing interest as a noninvasive way to study changes in water content and biochemical composition of lumbar intervertebral discs and vertebral bodies. This article reviews the current methodological problems and the feasibility of quantitative magnetic resonance imaging in the lumbar spine for investigations on water content and biological composition. This technique does not allow direct quantification of water content. Although biochemical variations may sensitively influence relaxation times and proton density under in vitro conditions, it is not feasible to obtain sufficiently reliable and specific information to monitor biochemical alterations associated with lumbar disc pathology in vivo.