Abstract
Study Design: A prospective observational study of 12 Adolescent Idiopathic Scoliosis patients undergoing corrective surgery.
Objective: To assess the recovery of respiratory function (specifically diaphragmatic function) after thoracotomy or thoraco-abdominal surgery for Adolescent Idiopathic Scoliosis (AIS) using spirometry and Sniff Nasal Inspiratory Pressure (SNIP).
Summary of Background Data: SNIP is one of the best measures of global inspiratory muscle strength and specifically of diaphragmatic muscle strength. FVC and FEV1 are a better measure of restrictive and obstructive lung function than muscle strength. To the best of our knowledge no study has specifically looked at the recovery of diaphragmatic function following scoliosis surgery.
Subjects: 6 patients (2M, 4F) with thoracic scoliosis underwent a thoracotomy followed by a second stage posterior instrumentation 5–7 days later. The other 6 patients (1M, 5F) with thoraco-lumbar curves had a single stage correction and instrumentation using thoraco-abdominal approach. All patients were operated by the same surgeon.
Outcome Measures: All patients underwent conventional lung function tests (spirometry) and SNIPs during their pre-operative assessment. Spirometry and SNIPs were repeated postoperatively before discharge, at 6 weeks, 3 months and 6 months follow up. The values were compared between the thoracic and thoraco-abdominal groups.
Results: Overall mean preoperative SNIP was 56.75 cm H2O and overall FVC was 2.79L. The mean SNIP in the thoracotomy group was 57.8 and 55.67 in the thoraco-abdominal group. The mean FVC in the thoracotomy group was 2.9 and in thoraco-abdominal group was 2.66. The difference between the 2 groups was not statistically significant. SNIP values returned to normal within 3 months in the thoraco-abdominal as well as in the thoracotomy groups. The FVC returned to within 95% of pre-operative values in 6 months in the two groups.
Conclusion: This study shows that SNIP return to pre-operative values within 3 months of scoliosis surgery after both thoracotomy and thoraco-abdominal approaches. The thoraco-abdominal approach appears not to have a more detrimental effect on global inspiratory muscle function and diaphragmatic function when compared to thoracotomy.
These abstracts were prepared by Mr. Brian J C Freeman FRCS (Tr & Orth). Correspondence should be addressed to him at The Centre for Spinal Studies and Surgery, University Hospital, Queens Medical Centre, Nottingham NG7 2UH.
