Clinical classification and surgical option of thoracolumbar paravertebral space-occupying lesion

English Keywords:Thoracolumbar spine  Paravertebral lesion  Surgical approach  Resection  Location  Type

English Abstract:

  【Abstract】 Objectives: To propose a new clinical classification of paravertebral space-occupying lesions of thoracolumbar spine and evaluate its reference value for the selection of surgical treatment. Methods: From January 2013 to December 2019, 35 patients with paravertebral space-occupying lesions of the thoracolumbar spine underwent surgical resection, including 15 males and 20 females, aged from 7 to 70 years (42.4±16.1 years). There were 6 cases of posterior median approach, 7 cases of paraspinal sacrospinalis muscle-splitting approach, 17 cases of retroperitoneal space approach and 5 cases of lesion posterior approach. The imaging features were retrospectively analyzed, and the paravertebral space-occupying lesions were divided into three types: type Ⅰ, located near the vertebral body, with a small part growing along the nerve root to the intervertebral foramen and not protruding into the central spinal canal; type Ⅱ, located outside the intervertebral foramen beside the vertebral body; and type Ⅲ, located in the erector spinae behind the vertebral arch. Each type was further divided into two subtypes of a and b according to the size of space-occupying lesions. Among them, patients with a long axis ≤50mm were classified as subtype a, and those with that more than 50mm were classified as subtype b. Three observers evaluated the classification twice(interval 1 week). The consistency of the analysis results was checked by Kappa-test. VAS score was compared before and after the operation, and at the last follow-up. The curative effect was evaluated combined with imaging results. Results: Among the 35 cases, 4 cases were of type Ⅰa, 3 cases type Ⅰb, 9 cases type Ⅱa, 14 cases type Ⅱb, 3 cases type Ⅲa, and 2 cases type Ⅲb. The Kappa of inter-observer agreement was 0.924-1, and the Kappa of intra-observer was 0.849-0.924, which were highly consistent. 6 cases were resected through the posterior median approach, which belonged to the thoracic segment Ⅰa(1) and Ⅱa(5) patients; 7 cases were resected through paraspinal sacrospinalis muscle-splitting approach, which belonged to the lumbar segment Ⅰa(3) and Ⅱa(4) patients; 17 cases were resected through the retroperitoneal space approach, belonged to the lumbar segment Type Ⅰb(3) and Ⅱb(14) patients; 5 cases were resected directly behind the lesion, and they were type Ⅲa(3) and Ⅲb(2) patients. 34 cases were completely removed at one stage, and 1 case failed to be completely resected. The patient′s symptoms improved significantly. There was no obvious loss of neurological function after operation. 33 patients were followed up for 3 to 90 months(42.5±33.3 months). Among them, 32 cases did not find tumor recurrence on MRI, and 1 case had recurrence of liposarcoma. The average VAS score was 7.7±1.6 points before operation, 2.4±1.3 points 1 month after operation, and 1.2±1.1 points at the last follow-up. Conclusions: Based on the location and size of paravertebral space-occupying lesions of the thoracolumbar spine, the reasonable clinical classification was proposed and the corresponding surgical treatment strategy can achieve satisfactory clinical outcomes.