Are We Neglecting Long Term Effects of Vertebral Shortening on Pulmonary Function in Spinal Tuberculosis?

Abstract

Background: In developing part of world, it is common to see near complete destruction of vertebral bodies in TB due to contiguous involvement of multiple vertebrae. This leads to frequent occurrence of spinal deformities including kyphosis. Resultant loss of vertebral column height & its effects on pulmonary function haven't been studied previously. Our study aims to assess effect of spinal TB with vertebral shortening on pulmonary function. 

Methods: 50 cases consisted of both operative & non operatively managed cases of spinal TB who presented to tertiary care institute between the years 2011 to 2016 were assessed. Vertebral height loss was assessed by SDI. All patients underwent pulmonary function testing and various  spirometry variables  were considered. Arm span was used as a surrogate marker for height. 

Findings: Study group consisted of 14 males & 36 females with mean age of 27.9 years. 11 patients with mean SDI of 2.72 ± 1.1 showed normal lung function. 36 patients showed a restrictive pattern of which 12 showed mild, 14 moderate and 10 showed severe pattern. Only 3 cases showed an Obstructive pattern. 36 patients had Thoracic affection, 13 patients had a thoracolumbar affection while 1 patient had a purely Lumbar affection. As the apex of the curve shifted proximally, the FVC% reduced and the decrement was statistically significant. Increase in the SDI value was associated with a fall in the vital capacity and FEV1. Increase in the kyphotic angle was associated with a deleterious effect on PFT results. SDI showed significant difference between Normal & restrictive pattern groups. 

Interpretations: Careful preservation of pulmonary function along with restoration of neurological function should be the aim of management of TB spine. Usually shortening procedures are better tolerated by spinal cord as compared to distraction. However, pulmonary dysfunction resulting from vertebral body height loss due to kyphosis is neglected.  This risk stratification will  further emphasize the need for early detection of this disease before the deformity sets in & need for long term observation for possible deterioration in lung function.

Funding Statement: The authors hereby declare that they have not received any funding for this
manuscript.

Declaration of Interests: Each author certifies that he or she has no commercial associations (e.g. consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article.

Ethics Approval Statement: Approval from the IRB was taken prior to commencement.