Congenital stenosis of lumbar spinal canal: comparison of results of surgical treatment for this and other causes of lumbar syndrome

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.

Clinical implications of lumbar developmental spinal stenosis on back pain, radicular leg pain, and disability

AIMS

To study the associations of lumbar developmental spinal stenosis (DSS) with low back pain (LBP), radicular leg pain, and disability.

METHODS

This was a cross-sectional study of 2,206 subjects along with L1-S1 axial and sagittal MRI. Clinical and radiological information regarding their demographics, workload, smoking habits, anteroposterior (AP) vertebral canal diameter, spondylolisthesis, and MRI changes were evaluated. Mann-Whitney U tests and chi-squared tests were conducted to search for differences between subjects with and without DSS. Associations of LBP and radicular pain reported within one month (30 days) and one year (365 days) of the MRI, with clinical and radiological information, were also investigated by utilizing univariate and multivariate logistic regressions.

RESULTS

Subjects with DSS had higher prevalence of radicular leg pain, more pain-related disability, and lower quality of life (all p < 0.05). Subjects with DSS had 1.5 (95% confidence interval (CI) 1.0 to 2.1; p = 0.027) and 1.8 (95% CI 1.3 to 2.6; p = 0.001) times higher odds of having radicular leg pain in the past month and the past year, respectively. However, DSS was not associated with LBP. Although, subjects with a spondylolisthesis had 1.7 (95% CI 1.1 to 2.5; p = 0.011) and 2.0 (95% CI 1.2 to 3.2; p = 0.008) times greater odds to experience LBP in the past month and the past year, respectively.

CONCLUSION

This large-scale study identified DSS as a risk factor of acute and chronic radicular leg pain. DSS was seen in 6.9% of the study cohort and these patients had narrower spinal canals. Subjects with DSS had earlier onset of symptoms, more severe radicular leg pain, which lasted for longer and were more likely to have worse disability and poorer quality of life. In these patients there is an increased likelihood of nerve root compression due to a pre-existing narrowed canal, which is important when planning surgery as patients are likely to require multi-level decompression surgery. Cite this article: Bone Joint J 2021;103-B(1):131-140.

Radiographic Cobb Angle: A Feature of Congenital Lumbar Spine Stenosis

PURPOSE

A low cost, reproducible radiographic method of diagnosing congenital lumbar spinal stenosis (CLSS) is lacking. We hypothesized that the Cobb angle for lumbar lordosis would be smaller in patients with CLSS, based on observations in our spine clinic patient population. Here, we compared lumbar lordosis Cobb angles with the radiographic ratio method in patients with normal spine imaging, degenerative spinal stenosis, and with CLSS.

MATERIALS AND METHODS

Orthopedic surgeons categorized patients with low back pain as "Normal," "Degenerative spinal stenosis," and "CLSS" based on clinical presentation and findings on lumbar magnetic resonance imaging. We included 30 patients from each cohort who had undergone lateral lumbar spine radiographs and lumbar magnetic resonance imaging. For each lateral radiograph, 2 measurement methods were used (1) 4-line lumbosacral Cobb angle between L2-S1 and (2) the ratio of the anteroposterior vertebral body diameter and spinal canal anteroposterior diameter at the L3 level. We performed logistic regression analyses of CLSS prediction by Cobb angle vs the ratio method in all three cohorts. Covariates included age, gender, and body mass index.

RESULTS

The radiographic Cobb angles were smaller in CLSS patients when compared to the degenerative disease and normal cohorts: a smaller radiographic Cobb angle showed higher odds ratio (OR) of predicting CLSS diagnosis compared to the radiographic ratio when compared with degenerative disease (OR = 0.28; 95% CI: 0.11-0.78, P = 0.01) and when compared with the normal cohort (OR = 0.46; 95% CI: 0.24-0.92, P = 0.03). Radiographic ratio measurements showed no difference between the three cohorts (P = 0.12). CLSS was associated with male gender (P = 0.04), younger age (P = 0.01), and higher body mass index (P = 0.01).

CONCLUSION

The radiographic Cobb angle method for lumbar lordosis may be useful for raising the possibility of CLSS as the diagnosis.

Stability-preserving decompression in degenerative versus congenital spinal stenosis: demographic patterns and patient outcomes

BACKGROUND CONTEXT

Although lumbar spinal stenosis often presents as a degenerative condition (degenerative stenosis [DS]), some patients present with symptoms from lifelong narrowing of the spinal canal. These patients have congenital stenosis (CS) and present with symptoms of stenosis at a younger age. Patients with CS often have a distinct pathophysiology with fewer degenerative changes but present with multilevel involvement. In the setting of neurologic symptoms, decompression alone while preserving stability has been proposed for both patient populations.

PURPOSE

The purpose of this study is to evaluate if the different etiology for narrowing in CS and DS results in a different natural history of pain progression, different locations requiring decompression, and different outcomes following a stability-preserving decompression procedure.

STUDY DESIGN/SETTING

This study used a retrospective cohort study patient sample: We retrospectively reviewed consecutive patients of a single surgeon with DS or CS who underwent surgical decompression without fusion between 2008 and 2014. Patients were excluded if they had undergone a previous lumbar surgical procedure (decompression or fusion) or follow-up less than 12 months.

OUTCOME MEASURES

Pre- and postoperative clinical outcome scores including visual analogue scale (VAS) and Oswestry Disability Index (ODI) were recorded. Postoperatively, data were collected regarding complications, the presence of new radicular or myelopathic symptoms, and necessity of reoperation in the lumbar spine.

METHODS

Demographic information included age, sex, body mass index, smoking status, and Charleston Comorbidity Index (CCI). Preoperative clinical symptoms as well as the presence of lower extremity radiculopathy and claudication were evaluated. Patients were determined to have a diagnosis of CS by the treating surgeon if primary radiographs revealed shortened pedicles and decreased cross-sectional area of the spinal canal as detailed by previous studies. Binary outcomes were compared between congenital and degenerative cohorts using bivariate and multivariate logistic regression. Multivariate regressions controlled for baseline patient and operative characteristics.

RESULTS

The average age of the DS cohort was 66.7±10.7 years, whereas for the CS group, it was 47.1±9.2 years. Average follow-up was 27.6 months. The patients with DS had significantly more comorbidities as shown by the CCI score (2.8±1.6 vs. 0.5±0.6); p<.001) and the American Society of Anesthesiologists (ASA) score ≥3 (52.8% vs. 11.1%; p<.001). Patients with CS presented with higher VAS back (8.0 vs. 5.1; p=.008) and leg (7.9 vs. 4.5; p<.001) scores. Patients with DS presented with significantly greater duration of preoperative back pain and leg pain (42.7 vs. 30.5 months; p=.042). Postoperatively, there were no significant differences in VAS back, leg, or ODI scores. However, a trend toward a lower VAS leg score was present in the patients with CS when compared with patients with DS (2.6±3.0 vs. 4.2±3.2; p<.117). Both patient groups experienced similar levels of symptomatic relief and improvement in VAS and ODI scores. There were no significant differences in new-onset radicular symptoms requiring conservative treatment or reoperation. In both groups combined, 81.9% of patients reported resolution of lower extremity symptoms at final follow-up. Overall, 20.6% of patients experienced new lower-extremity radicular symptoms after a period of resolution of symptoms postoperatively. There were significantly more reoperations following surgical decompression in patients with DS (13.9% vs. 2.8%; p=.02).

CONCLUSIONS

Patients with CS and patients with DS respond well to decompression alone, without a supplemental fusion, despite differences in pain experience and presentation. The localization of pathology requiring decompression is similar. The patients with DS were more susceptible to require another operation resulting in a fusion, which confirms the theory that initial microinstability can progress in DS, but is likely not part of the disease process in CS. At just over 2 years after decompression, patients with CS may not need to be treated by a fusion in the setting of lower back pain; however, longer-term follow up is necessary to further assess these outcomes.

Anatomic radiological variations in developmental lumbar spinal stenosis: a prospective, control-matched comparative analysis

BACKGROUND CONTEXT

Developmental lumbar spinal stenosis is a maldevelopment of the dorsal spinal elements involving short pedicles and a trefoil bony spinal canal that increases the likelihood of neural compression at an earlier age.

PURPOSE

To identify radiographically the anatomic variations caused by the maldevelopment of the infrequently characterized dorsal spinal elements.

STUDY DESIGN

A prospective, control-matched comparative analysis.

METHODS

Magnetic resonance imaging (MRI) and anteroposterior (AP) plain radiographs of 66 patients (mean age, 40.7 years) selected and randomized prospectively and compared with images of 45, age- and gender-matched control subjects. Variables assessed included spinal canal cross-sectional area (CSA), thecal sac AP and transverse canal diameters (CSA), and interpedicular distance. All were expressed in ratios with vertebral body diameter (VBD), interlaminar angle, stenosis grade, and MRI evidence of disc degeneration.

RESULTS

In the stenosis cohort, global pathology and multilevel involvement with L3, L4, and L5 segments were involved more commonly and severely. Severe stenosis, at L1, L2, and S1 occurs infrequently. Multivariate analysis demonstrated a statistically significant reduction in spinal canal CSA-to-vertebral body CSA ratio, AP spinal canal diameter-to-VBD ratio on axial and sagittal magnetic resonance images, and plain radiograph interpedicular distance-to-VBD ratio at all levels. Interlaminar angle and the transverse spinal canal diameter-to-VBD ratio were reduced significantly in the stenosed cohort at all levels, except L1. No statistically significant difference regarding the incidence of disc degeneration on MRI between the two cohorts, as well as thecal sac CSA-to-spinal canal CSA ratios across all levels were observed, except for L3 and S1 (p<.05).

CONCLUSIONS

Three spinal canal morphologies were identified: (1) "flattened" canal with predominantly reduced spinal canal AP diameter, (2) spinal canal with predominantly reduced interlaminar angle, and (3) global reduction of all canal parameters. Early age at presentation and subtle spondylosis, although typical, should not be considered the identifying, differentiating factors.

Lumbar canal stenosis: results in 40 patients surgically treated

Authors present the clinical and neuroradiological characteristics of 40 patients treated for lumbar canal stenosis during a 10 years experience. The usefulness of computed tomography in comparison with myelography and plain X-rays of the spine is stressed. The surgical treatment was wide laminectomy involving one or more levels (two to four) plus an eventual foraminotomy but without discectomy. All patients were followed up and in 85% of cases a reduction of clinical symptoms was observed. Residual symptoms were also present in some of the improved patients, they generally accepted them without great dismay.