Should asymptomatic cervical stenosis be treated in the setting of progressive thoracic myelopathy? A systematic review of the literature

Development of a comprehensive treatment algorithm for tandem spinal stenosis: decision making and surgical strategy

BACKGROUND CONTEXT

Tandem spinal stenosis (TSS) can present with a constellation of myriad neurological symptoms and signs. Whole spine MRI has improved the diagnosis but does not aid therapeutic decision-making. While most studies have focused on cervico-lumbar TSS, there is inadequate literature on TSS of other regions. Further, there are no guidelines on the optimal surgical strategy for patients with TSS.

STUDY DESIGN

Retrospective evaluation of prospectively collected data PURPOSE: To develop a clinico-radiological treatment algorithm for TSS involving all the regions of the spine PATIENT SAMPLE: About 238 patients treated for TSS with a minimum follow-up of 2 year.

METHODOLOGY

The patients were classified based on the areas of stenosis namely cervico-lumbar (Type A -186), cervico-thoracic (Type B -11), thoracolumbar (Type C -24), and cervical, thoracic & lumbar (Type D -17). The criteria for diagnosis of TSS were cord compression and T2 signal intensity changes in cervical/ thoracic regions, and/or Schiza's grade ≥C lumbar canal stenosis (LCS). In the sequence of surgical algorithm, clinical severity was taken as the prime factor followed by cord signal changes. In clinical severity, symptoms were given predominance over clinical signs, myelopathy over radiculopathy and proximal over distal compressions. The outcomes were evaluated through Nurick's grade (NG) and ODI.

RESULTS

Type A cervico-lumbar TSS was divided into four sub-types. Type A1-patients with clinical myelopathy without symptoms of LCS underwent cervical decompression alone (n=58). NG improved from 3.8±0.98 to 1.74±0.74 (p<.05). Only 11(18%) required lumbar decompression later. Patients with LCS (Type A2) without clinical myelopathy underwent lumbar decompression alone (n=97). Four (4.1%) developed myelopathy during follow-up requiring a cervical surgery. Patients with predominant LCS symptoms with only signs of myelopathy (Type A3, n=7) underwent lumbar decompression initially but all required cervical surgery within 2 years. Type A4 (n=24) with both myelopathy and claudication symptoms were treated by combined staged decompressions procedures. The NG improved from 3.4±0.7 to 1.6±0.4 (p<.05). Type B (n=11) had patients with myelopathy due to compression at cervical and thoracic regions. They were sub-divided based on upper limb myelopathy. In patients with both upper and lower limb myelopathy (Type B1, n=11), cervical decompression was done first (n=6) followed by staged thoracic decompression. The NG improved from 4.6±0.5 to 1.8±0.3 (p<.05). In patients with predominant lower limb myelopathy (Type B2, n=5), only thoracic surgery was performed. Only one required cervical surgery later. In Type C thoracic & lumbar TSS (n=24), 20 were treated by thoracic decompression based on signs of myelopathy. The mean NG improved from 4.1±0.7 to 1.9±0.9 (p<.05). Six cases required lumbar level surgery later. Four patients who had only LCS symptoms underwent lumbar decompression. Type D with stenosis at all three regions presented variedly, and underwent staged decompression (n=17).

CONCLUSION

Based on clinical features of myelopathy and claudication, along with specific diagnostic MRI criteria, the present study comprehensively classified all possible types of TSS. The algorithm provides specific surgical strategies for each subtype, based on a large cohort of patients. More than MRI evidence of stenosis and signal changes, clinical symptoms and signs were helpful in formulating treatment.

Tandem stenosis of the cervical and thoracic spine: a systematic review

BACKGROUND

Tandem spinal stenosis (TSS) is a condition characterized by the narrowing of the spinal canal in multiple segments of the spine. Predominantly observed in the cervical and lumbar regions, TSS also manifests in the conjunction of the cervical and thoracic spine. The simultaneous occurrence of cervical and thoracic spinal stenosis engenders intricate symptoms, potentially leading to missed and delayed diagnosis. Furthermore, the presence of tandem cervical and thoracic stenosis (TCTS) introduces a notable impact on the decision-making calculus of surgeons when contemplating either one-staged or two-staged surgery. Currently, there is no agreed-upon strategy for surgical intervention of TCTS in the literature.

METHODS

Medical databases in English (Pubmed, Web of Science, Embase, the Cochrane Database of Systematic Reviews) and Chinese (CNKI, Wanfang Data, VIP CMJD) were searched using Medical Subject Heading queries for the terms "tandem cervical and thoracic stenosis", "cervical stenosis AND thoracic stenosis", "tandem spinal stenosis" and "concomitant spinal stenosis" from January 1980 to March 2023. We included studies involving adult individuals with TCTS. Articles exclusively focused on disorders within a single spine region or devoid of any mention of spinal disorders were excluded.

RESULTS

Initially, a total of 1625 literatures underwent consideration for inclusion in the study. Following the elimination of the duplicates through the utilization of EndNote, and a meticulous screening process involving scrutiny of abstracts and full-texts, 23 clinical studies met the predefined inclusion criteria. Of these, 2 studies solely focused on missed diagnosis, 19 studies exclusively discussed surgical strategy for TCTS, and 2 articles evaluated both surgical strategy and missed diagnosis.

CONCLUSION

Our study revealed a missed diagnosis rate of 7.2% in TCTS, with the thoracic stenosis emerging as the predominant area susceptible to oversight. Therefore, the meticulous identification of TCTS assumes paramount significance as the inaugural step in its effective management. While both one-staged and two-staged surgeries have exhibited efficacy in addressing TCTS, the selection of the optimal surgical plan should be contingent upon the individualized circumstances of the patients.

Risk Factor Analysis of Surgery-related Complications in Primary Thoracic Spine Surgery for Degenerative Diseases and Characteristics of the Patients Also Undergoing Surgery on the Cervical and/or Lumbar Spine

STUDY DESIGN

A retrospective cohort study using prospectively collected data.

OBJECTIVE

This study primarily aimed to investigate the risk factors for surgery-related complications in primary thoracic spine surgery for degenerative diseases using a surgeon-maintained database. The secondary purpose was to elucidate the characteristics of surgically treated thoracic myelopathy that also required cervical and/or lumbar spine surgery in the study period.

SUMMARY OF BACKGROUND DATA

Few studies reported surgical complications and the feature of tandem spinal stenosis in thoracic myelopathy in detail because of their rarity.

MATERIALS AND METHODS

This study included 840 thoracic myelopathy patients undergoing primary surgery for degenerative diseases from 2012 to 2021, investigating the effects of diseases, surgical procedures, and patient demographics on postoperative neurological deterioration, dural tear, dural leakage, surgical-site infection, and postoperative hematoma. In thoracic myelopathy patients who were surgically treated and also undergoing cervical and/or lumbar surgery, we investigated the proportion, the effects of diseases, and the order and intervals between surgeries.

RESULTS

Multivariate logistic regression revealed that significant risk factors ( P <0.05) for postoperative neurological deterioration were intervertebral disk herniation [odds ratio (OR): 4.59, 95% confidence interval (CI): 1.32-16.0) and degenerative spondylolisthesis (OR: 11.1, 95% CI: 2.15-57.5). Ossification of the ligamentum flavum (OR: 4.12, 95% CI: 1.92-8.86), anterior spinal fusion (OR: 41.2, 95% CI: 4.70-361), and circumferential decompression via a posterior approach (OR: 30.5, 95% CI: 2.27-410) were risk factors for dural tear. In thoracic myelopathy patients surgically treated, 37.0% also underwent degenerative cervical and/or lumbar surgery.

CONCLUSIONS

Pathologies involving anterior decompression and instability increased the risk of postoperative neurological deterioration. The risk of dural tear was increased when dura mater adhesions were likely to be directly operated upon. It should be recognized that a relatively high proportion (37.0%) of surgically treated thoracic myelopathy patients also underwent cervical and/or lumbar surgery.

Differentiation Between Compressive Cervical and Thoracic Myelopathy Using the Central Motor Conduction Time Ratio

PURPOSE

Thoracic myelopathy is a rare condition whose diagnosis is often missed or delayed. This study aimed to differentiate between cervical and thoracic myelopathy using motor-evoked potential testing.

METHODS

The authors included 835 patients with compressive cervical myelopathy and 94 patients with compressive thoracic myelopathy. Myelopathy using motor-evoked potentials were recorded from the bilateral abductor digiti minimi and abductor hallucis muscles through transcranial magnetic stimulation. The peripheral conduction time was measured through electrical stimulation of the ulnar and tibial nerves; moreover, the central motor conduction time (CMCT) was calculated by subtracting the peripheral conduction time from the myelopathy using motor-evoked potential latency.

RESULTS

The most accurate differentiation between compressive cervical myelopathy and compressive thoracic myelopathy was achieved by the CMCT ratios (CMCT-ADM:CMCT-AH; cutoff value of 0.490, sensitivity of 83.0%, and specificity of 80.5%). After excluding patients with compressive cervical myelopathy who had spinal cord compression at C6-7, the cutoff value was 0.490, with a sensitivity of 83.0% and specificity of 87.3%.

CONCLUSIONS

Determining the CMCT ratio (cutoff value of 0.490) through motor-evoked potential testing could facilitate differentiation between compressive cervical myelopathy and compressive thoracic myelopathy.

Current understanding of tandem spinal stenosis: epidemiology, diagnosis, and surgical strategy

Tandem spinal stenosis (TSS) is defined as the concomitant occurrence of stenosis in at least two or more distinct regions (cervical, thoracic, or lumbar) of the spine and may present with a constellation of signs and symptoms. It has four subtypes, including cervico-lumbar, cervico-thoracic, thoraco-lumbar, and cervico-thoraco-lumbar TSS. The prevalence of TSS varies depending on the different subtypes and cohorts.

The main aetiologies of TSS are spinal degenerative changes and heterotopic ossification, and patients with developmental spinal stenosis, ligament ossification, and spinal stenosis at any region are at an increased risk of developing TSS.

The diagnosis of TSS is challenging. The clinical presentation of TSS could be complex, concealed, or severe, and these features may be confusing to clinicians, resulting in an incomplete or delayed diagnosis. Additionally, a consolidated diagnostic criterion for TSS is urgently required to improve consistency across studies and form a basis for establishing treatment guidelines.

The optimal treatment option for TSS is still under debate; areas of controversies include choice of the decompression range, choice between simultaneous or staged surgical patterns, and the order of the surgeries.

The present study reviews publications on TSS, consolidates current awareness on prevalence, aetiologies, potential risk factors, diagnostic dilemmas and criteria, and surgical strategies based on TSS subtypes. This is the first review to include thoracic spinal stenosis as a candidate disorder in TSS and aims at providing the readers with a comprehensive overview of TSS.