gms | German Medical Science

Objective: The incidence of degenerative thoracic spinal stenosis (TSS) as underlying pathology for clinical myelopathy is not precisely known, but low compared to cervical spinal stenosis, and larger case series are only available for the Asian region. We present one of the largest European series of TSS patients to evaluate incidence and clinical outcome after posterior decompression via an unilateral or bilateral approach.

Methods: 28 patients who underwent surgical treatment for TSS between 2013 and 2018 in a university neurosurgical clinic were included. We investigated the patients’ characteristics, imaging and surgical parameters as well as outcomes and quality-of-life (QOL) after long-term follow-up.

Results: From altogether 645 patients with decompressive surgery due to degenerative spondylotic myelopathy, 28 patients suffered from thoracic spinal stenosis, accounting within 6 years for 4.3% of patients in this population. Mean age was 68.2 years, with a predominance of the female sex (m:f=1:1.3). The most frequent symptoms were spinal ataxia (61%) and sensory changes (46%) with a mean duration of 7.6months. There were 29 levels of stenosis (one patient with 2-level stenosis), mostly resulting from a combined osseous and ligamentous hypertrophy and disc prolapse predominantly located below Th9 (72%); the median Naganawa grade was 3 (i.e. severe cord impingement/deformity). 19 patients with a lateralized compression of the spinal cord underwent bilateral decompression via an unilateral approach (fenestration/hemilaminectomy with "undercutting" procedure) and 9 patients with circular pathology underwent bilateral-approached decompression via laminectomy. No patient required additive stabilization. There were no significant differences of patients’ characteristics, intraoperative blood loss, operation time and length of in-patient stay between both surgical groups. Independent on the mode of surgical decompression, the spinal canal was significantly (p<0.001) widened (median Naganawa grade: 0, i.e. no stenosis) and back pain (p=0.04), myelopathic symptoms (mJOA-Score: p=0.01) and QOL (Oswestry-Disability-Index: p=0.03; SF-36-MCS: p=0.01) were significantly improved at long-term follow-up (mean: 35.1months).

Conclusion: Non-tumorous clinical mylopathy is caused in about 4% of the patients by spondylotic compression of the spinal cord at predominantly the lower thoracic spine and can be effectively treated by surgical decompression via both a unilateral or bilateral approach.