Tandem spinal stenosis
Tandem spinal stenosis (TSS) is a degenerative spinal condition characterized by spinal canal narrowing at 2 or more distinct spinal levels. It is an aging-related condition that is likely to increase as the population ages, but which remains poorly described in the literature.
Management
It is a common condition present in up to 60% of patients with spinal stenosis. This disorder, however, is often overlooked, which can lead to serious complications. Identification of tandem spinal stenosis is paramount as a first step in management and, although there is still no preferred intervention, both staged and simultaneous procedures have been shown to be effective. Surgeons may utilize a single, staged, or combined approach to decompression, always addressing cervical myelopathy as a priority 1).
A systematic review and meta-analysis of observational studies were conducted to compare the outcomes between simultaneous decompression of all stenotic regions (cervical and lumbar, Group 1) and decompression of only the most symptomatic stenotic region (cervical/lumbar, Group 2) in patients with TSS.
Methods: A systematic review was conducted, and a comprehensive literature search with well-established inclusion and exclusion criteria with JOA score as an outcome measure was done on PubMed, Google Scholar, and EMBASE database (till January 2021). Observational studies reporting outcomes after simultaneous decompression or only the most symptomatic region were included. NIH quality assessment tool was used to check the quality of each study, and treatment effects were calculated using Dersimonian and Laird random effects model.
Results: Ten studies were included in the analysis out of which all were retrospective observational studies (Level 4 evidence) except one (Level 3 evidence). Overall proportional meta-analysis showed no significant difference in change in JOA scores, operative time, blood loss, total and major complications between Group 1 and Group 2. However, minor complications were significantly increased on performing decompression of both regions simultaneously (p = 0.04). On performing subgroup analysis comparing cervical surgery cohort with lumbar surgery cohort, no difference was found in change in JOA score and requirement of second-stage surgery.
Conclusion: Decompression of the most symptomatic region alone irrespective of its location has equal clinical outcomes with less complication rate than simultaneous decompression in patients with TSS 2).
Case series
The purpose of a study of van Eck et al. was to develop a simple and clinically useful morphological classification system for congenital lumbar spinal stenosis using sagittal MRI, allowing clinicians to recognize patterns of lumbar congenital stenosis quickly and be able to screen these patients for tandem cervical stenosis.
Forty-four subjects with an MRI of both the cervical and lumbar spine were included. On the lumbar spine MRI, the sagittal canal morphology was classified as one of three types: Type I normal, Type II partially narrow, Type III globally narrow. For the cervical spine, the Torg-Pavlov ratio on X-ray and the cervical spinal canal width on MRI were measured. Kruskal-Wallis analysis was done to determine if there was a relationship between the sagittal morphology of the lumbar spinal canal and the presence of cervical spinal stenosis.
Subjects with a type III globally narrow lumbar spinal canal had a significantly lower cervical Torg-Pavlov ratio and smaller cervical spinal canal width than those with a type I normal lumbar spinal canal.
A type III lumbar spinal canal is a globally narrow canal characterized by a lack of spinal fluid around the conus. This was defined as “functional lumbar spinal stenosis” and is associated with an increased incidence of tandem cervical spinal stenosis 3).
Pennington et al. sought to determine the impact of primary lumbar decompression on quality of life (QOL) outcomes in patients with symptomatic TSS.
They retrospectively reviewed 803 patients with clinical and radiographic evidence of TSS treated between 2008 and 2014 with a minimum 2-year follow-up. The records of patients with clinical and radiographic evidence of concurrent cervical and lumbar stenosis were reviewed. Prospectively gathered QOL data, including the Pain Disability Questionnaire (PDQ), Patient Health Questionnaire-9 (PHQ-9), EuroQOL-5 Dimensions (EQ-5D), and Visual Analogue Scale (VAS) for low back pain, were assessed at the 6-month, 1-year, and 2-year follow-ups.
Of 803 identified patients (mean age 66.2 years; 46.9% male), 19.6% underwent lumbar decompression only, 14.1% underwent cervical + lumbar decompression, and 66.4% underwent conservative management only. Baseline VAS scores were similar across all groups, but patients undergoing conservative management had better baseline QOL scores on all other measures. Both surgical cohorts experienced significant improvements in the VAS, PDQ, and EQ-5D at all time points; patients in the cervical + lumbar cohort also had significant improvement in the PHQ-9. Conservatively managed patients showed no significant improvement in QOL scores at any follow-up interval.
Lumbar decompression with or without cervical decompression improves low back pain and QOL outcomes in patients with TSS. The decision to prioritize lumbar decompression is therefore unlikely to adversely affect long-term quality-of-life improvements 4).
Cervical spine surgery with or without follow-up lumbar spine surgery significantly improves neck pain in patients with TSS. In contrast, cervical spine surgery in these patients does not improve lumbar symptoms. Lumbar spine surgery also did not improve low back pain or quality of life. Future prospective studies are necessary to examine the impact of lumbar decompression alone on cervical spine symptoms in patients with TSS 5).