Computerised tomography in lumbar stenosis. A preliminary report

Congenital Stenosis of the Spine-A Cross-Sectional Study of 1019 Whole-Spine Computed Tomography Scans to Determine Prevalence and Association Among Multilevel, Tandem, and Triple Region Stenosis

BACKGOUND

Patients with congenital stenosis of the spine (CSS) present with clinical symptoms at an early age and fewer degenerative hypertrophic changes than the more common degenerative cohort. Literature is lacking in the true prevalence of CSS affecting the 3 segments of the spine in isolation, as well as in tandem in the Indian subcontinent.

METHODS

Anteroposterior spinal canal diameter in axial plane computed tomography at the midvertebral level was measured in asymptomatic patients with whole-spine computed tomography. Spinal canal stenosis was defined as a diameter of <12 mm for the cervical region, <12 mm for the thoracic region, and <13 mm for the lumbar region. Single-level and multilevel stenosis, as well as tandem and triple-region stenosis, were evaluated.

RESULTS

The results show the prevalence of CSS as 16.6%, 11.5%, and 20.1% involving the cervical, thoracic, and lumbar spine, respectively. Single-level stenosis affected 90.6%, 94%, and 79.8% of the patients with cervical, thoracic, and lumbar CSS, respectively. Tandem stenosis affected 10.4% of the population (n = 104), with cervicolumbar stenosis being the most prevalent (n = 51, 5%). The presence of CSS in any one segment of the spine was significantly associated with the presence of stenosis at one of the other segments (P < 0.05). Triple-region stenosis was seen in 0.3% (n = 3) patients.

CONCLUSIONS

The prevalence of cervical, thoracic, lumbar and tandem stenosis from our study is established at 16.6%, 11.5%, 20.1%, and 10.4%. Additionally, our study demonstrates the association between stenosis of the different regions of the spine.

Prevalence and Definition of Multilevel Lumbar Developmental Spinal Stenosis

STUDY DESIGN

Cross-sectional study.

OBJECTIVES

To define multilevel lumbar developmental spinal stenosis (DSS) using a composite score model and to determine its prevalence.

METHODS

This was a cohort study of 2385 openly recruited subjects with lumbosacral (L1-S1) MRIs. All subjects with previous spinal surgery or spinal deformities were excluded. The anteroposterior (AP) vertebral canal diameter was measured by two independent observers. Any associations between level-specific vertebral canal diameter and subject body habitus were analysed with non-parametric tests. Three or more stenotic levels, equivalent to a composite score of 3 or more, were considered as multilevel DSS. The median values of these subjects' AP canal diameters were used to construct the multilevel DSS values. Receiver operating characteristic analysis was utilized to determine the ability of these cut-off values to screen for DSS by presenting their area under curve, sensitivity and specificity.

RESULTS

Subject body habitus was poorly correlated with AP vertebral canal diameter. Multilevel DSS was identified as L1<19 mm, L2<19 mm, L3<18 mm, L4<18 mm, L5<18 mm, S1<16 mm with 81%-96% sensitivity and 72%-91% specificity. The prevalence of multilevel DSS in this cohort was 7.3%.

CONCLUSIONS

Utilizing a large homogeneous cohort, the prevalence of multilevel DSS is determined. Our cut-offs provide high diagnostic accuracy. Patients with multiple levels that fulfil these criteria may be at-risk of spinal canal compressions at multiple sites.

LEVEL OF EVIDENCE

III.

Pedigree analysis of lumbar developmental spinal stenosis: Determination of potential inheritance patterns

Lumbar developmental spinal stenosis (DSS) refers to multilevel pre-existing narrowed spinal canals, which predispose to neural compromise. The objective of this study is to identify any inheritance pattern of DSS by utilizing pedigree charts. This was a case series of 13 families with a total of 80 subjects having magnetic resonance imaging (MRI) from L1 to S1. Cases (subjects with DSS) or controls (subjects without DSS) were identified by measuring their anteroposterior (AP) vertebral canal diameters. Multilevel model analyses were also performed to evaluate whether there is substantial clustering of observations within the families, and the effect of multilevel DSS. The intraclass correlation coefficient (ICC) and Akaike information criteria (AIC) were compared between models. Correlations between subject demographics and AP vertebral canal diameter were statistically insignificant at all levels. Only vertebral canal cross-sectional area, and axial and sagittal vertebral canal diameter were found to be statistically different between cases and controls at all levels (all p < .05). Both males and females were affected by DSS and there was no skipping of generation, which highly suggested DSS followed an autosomal dominant inheritance pattern. After accounting for multilevel DSS, there was a drop of more than 10 in AIC and some variances were also explained within families. This is the first study that suggests multilevel lumbar DSS to have an autosomal dominant inheritance pattern. Within families with a background of DSS, subjects had a smaller canal size, contributed by shortened axial and sagittal AP vertebral canal diameter, and smaller canal cross-sectional area.

The profile of the spinal column in subjects with lumbar developmental spinal stenosis

AIMS

The aim of this study was to determine the differences in spinal imaging characteristics between subjects with or without lumbar developmental spinal stenosis (DSS) in a population-based cohort.

METHODS

This was a radiological analysis of 2,387 participants who underwent L1-S1 MRI. Means and ranges were calculated for age, sex, BMI, and MRI measurements. Anteroposterior (AP) vertebral canal diameters were used to differentiate those with DSS from controls. Other imaging parameters included vertebral body dimensions, spinal canal dimensions, disc degeneration scores, and facet joint orientation. Mann-Whitney U and chi-squared tests were conducted to search for measurement differences between those with DSS and controls. In order to identify possible associations between DSS and MRI parameters, those who were statistically significant in the univariate binary logistic regression were included in a multivariate stepwise logistic regression after adjusting for demographics. Odds ratios (ORs) and 95% confidence intervals (CIs) were reported where appropriate.

RESULTS

Axial AP vertebral canal diameter (p < 0.001), interpedicular distance (p < 0.001), AP dural sac diameter (p < 0.001), lamina angle (p < 0.001), and sagittal mid-vertebral body height (p < 0.001) were significantly different between those identified as having DSS and controls. Narrower interpedicular distance (OR 0.745 (95% CI 0.618 to 0.900); p = 0.002) and AP dural sac diameter (OR 0.506 (95% CI 0.400 to 0.641); p < 0.001) were associated with DSS. Lamina angle (OR 1.127 (95% CI 1.045 to 1.214); p = 0.002) and right facet joint angulation (OR 0.022 (95% CI 0.002 to 0.247); p = 0.002) were also associated with DSS. No association was observed between disc parameters and DSS.

CONCLUSION

From this large-scale cohort, the canal size is found to be independent of body stature. Other than spinal canal dimensions, abnormal orientations of lamina angle and facet joint angulation may also be a result of developmental variations, leading to increased likelihood of DSS. Other skeletal parameters are spared. There was no relationship between DSS and soft tissue changes of the spinal column, which suggests that DSS is a unique result of bony maldevelopment. These findings require validation in other ethnicities and populations. Level of Evidence: I (diagnostic study) Cite this article: Bone Joint J 2021;103-B(4):725-733.

A systematic review of developmental lumbar spinal stenosis

PURPOSE

To systematically evaluate any consensus for the etiology, definition, presentation and outcomes of developmental lumbar spinal stenosis (DLSS).

METHODS

A comprehensive literature search was undertaken by 2 independent reviewers with PubMed, Ovid, and Web of Science to identify all published knowledge on DLSS. Search terms included "developmental spinal stenosis" or "congenital spinal stenosis" and "lumbar". The inclusion criteria were English clinical studies with sample size larger than 8, articles examining the etiology, diagnostic criteria, surgical outcomes of DLSS, and its association with other spinal pathologies. Articles that did not specify a developmental component were excluded. The GRADE approach was used to assess their quality of evidence.

RESULTS

The initial database review found 404 articles. Twenty articles with moderate to very low quality met the inclusion criteria for analysis. The bony canal diameter was significantly shorter in patients with DLSS than normal subjects. In addition, the risk of re-operation on adjacent levels (21.7%) was high which could be explained by multi-level stenosis. However, there was a lack of consensus on the methodology of diagnosing DLSS and on its specific surgical techniques.

CONCLUSION

Multi-level stenosis and re-operation at adjacent levels are especially common with DLSS. Identification of these individuals provides better prognostication after surgery. However, current literature provides few consensus on its definition and the required surgical approach. Besides, there are limited reports of its etiology and association with other spinal pathologies. Due to these limitations, standardizing the definition of DLSS and investigating its etiology and expected clinical course are necessary.

The evolution of partial undercutting facetectomy in the treatment of lumbar spinal stenosis

Decompression of lumbar spinal stenosis is the most common spinal surgery in those over 60 years of age. While this procedure has shown immediate and durable benefits, improvements in outcome have not changed significantly. Technical aspects of surgical decompression have evolved significantly. The recently introduced ultrasonic bone cutter allows a precise and safe peri-neural bone resection. The principles of preservation of stability, as described by Getty et al. have remained as relevant as when these were described 40 years ago.

[Symptomatic lumbar spinal stenosis: diagnostic evaluation and therapeutic strategies]

Lumbar spinal stenosis is a common problem in daily routine practice. In the vast majority of cases stenosis is caused by degenerative changes of the lumbar spine with neurogenic claudication being the typical symptom. This is defined as sciatic pain and discomfort which deteriorates during walking and standing, leading to progressive neurological deficits. The diagnostic evaluation is based on the typical history of the patient and the clinical examination followed by magnetic resonance imaging (MRI) and flexion-extension X-ray films as the most sensitive diagnostic tool. When clinical symptoms are mild, conservative treatment might be an option but in severely disabled patients and/or in cases of relevant neurological deficits surgical decompression, in special cases combined with instrumentation should be favoured when clinical and radiological findings match. In these cases an improvement of the clinical symptoms can be achieved in up to 90% of the patients.

Reliability in grading the severity of lumbar spinal stenosis

Stenosis of the lumbar spinal canal is a major cause of disability and lost productivity. Computed tomography (CT) is used commonly to assess the presence and severity of spinal stensosis, because it is relatively inexpensive, readily available, and has few adverse effects. The ability of four surgeons to agree about the presence and severity of lumbar spinal stenosis based on plain CT scans was evaluated from 30 scans of varying stenosis severity (normal to severe). Kappa, a measure of chance-corrected agreement, was calculated. Surgeons exhibited moderate agreement for the presence or absence of spinal stenosis (kappa = 0.58+/-0.06). Agreement regarding the severity of stenosis, when present, was poor (kappa = 0.26+/-0.04). The ability of surgeons to agree was not improved when individual features of the CT scans were assessed (facet joint arthrosis, ligamentum flavum hypertrophy, disk protrusion, and nerve root impingement). This study suggests that CT scans are not a reliable method by which to examine the severity of lumbar spinal stenosis.

Mechanical properties of the human lumbar dura mater

BACKGROUND AND OBJECTIVES

This study aimed to evaluate the transverse and longitudinal distensibility of the posterior human lumbar dura mater. Results are compared with previous literature on biomechanical property studies. Possible clinical implications were also examined.

METHODS

Samples of human dural sac were obtained from autopsy studies in three adult male cadavers. Dural sac samples were sectioned longitudinally to measure transverse and longitudinal distensibility, thickness and circumference.

RESULTS

It was recorded that the posterior lumbar dura mater was easily distensible only in the transverse direction. The longitudinal force required to distend and rupture the posterior lumbar dura mater samples is 3.5 to 6.7 times greater than the force to produce a transversal rupture.

CONCLUSION

Depending on the local cerebrospinal fluid pressure, the documented easier transverse distensibility of the posterior lumbar dura mater may allow greater contact of the lumbar dural sac with the wall of the lumbar vertebral canal. This fact may affect the diffusion of solutions introduced into epidural space.

The shape of the human lumbar vertebral canal

Literature on the anatomy of the human vertebral column characterizes the shape of the lumbar vertebral canal as triangular. The purpose of the present study was to determine the precise shape of the lumbar vertebral canal. Ten lumbar vertebral columns of adult male cadavers were dissected. Two transverse sections were performed in the third lumbar vertebra. One section was performed at the level of the lower border of the ligamenta flava, and the other section was performed at the level of the pedicles. The shape of the lumbar vertebral canal at the level of the pedicles tends to be oval or circular, whereas the shape of the lumbar vertebral canal at the level of the lower border of the ligamenta flava is triangular. Thus, the shape of the human lumbar vertebral canal is not exclusively triangular, as reported in the literature. It is related to the level of the transversal section performed on the lumbar vertebra. This finding should be taken into consideration among factors involved in the spread of solutions introduced into the epidural space.

Quantitative assessment of the normal adult spinal canal at the fourth lumbar vertebra by computed tomography

We reviewed the computed tomographic (CT) studies of 105 adults with various complaints. Spinal canal diameters were measured by CT using both the conventional and Jones-Thomson (JT) techniques at the level of the fourth lumbar vertebra. The data were statistically assessed in an attempt to define spinal stenosis.

Computed tomography in orthopedics

The enormous interest in CT scanning appears fully justified as this remarkable technique continues its development. In orthopedics, it has a variety of roles to play: in trauma, tumor management, and developmental disorders. As experience with the CT scan in musculoskeletal disease is accumulated, new applications will undoubtedly become apparent, adding to the already impressive list.

Efficacy of CT scanning in a group of 174 patients with orthopedic and musculoskeletal problems

One hundred and seventy-four patients with orthopedic and musculoskeletal problems received computed tomography (CT) scans between January 1979 and July 1980. There were 34 trauma patients, 35 patients with known or suspected primary tumors, 20 patients with metastases, 18 patients with suspected spinal stenosis, 25 patients with disc problems, five patients with infections, 13 children with congenital anomalies, and 24 patients with miscellaneous problems. The CT scans proved useful in all the pediatric cases, 97% of the trauma patients, and in the majority of patients with tumors. It appears that absolute indications for CT scanning in orthopedic patients include acute trauma to the spine, pelvis, hip, and shoulder girdles as well as in children with congenital spinal anomalies. Relative indications include determining the extent of the tumor and also aiding in the correct approach for biopsying a lesion.

Analysis of operated cases with lumbar renal stenosis

Twenty-seven patients with spinal stenosis all diagnosed at the surgical exposure and treated with decompression are analysed. The material is divided into three groups according to the preoperative symptoms, those with claudication, those with back and leg pains and those with mixed symptoms. All were myelographed. The radicality of the decompression varied. Excellent and good results were obtained in a total of about 60 per cent. No difference, however, was seen between the three groups. A positive myelography (AP diameter less than 11 mm) was found in all cases with excellent and good results. The postoperative extent of the decompression was studied with a CT-scanner. Here a correlation was found between the range of decompression of the lateral recess and the result of the operation. Also the results seemed to be better with a shorter duration of the symptoms preoperatively.