Prone thoracoscopic release does not adversely affect pulmonary function when added to a posterior spinal fusion for severe spine deformity

STUDY DESIGN.: Prospective clinical study. OBJECTIVE.: To analyze the effect of adding a thoracoscopic release and fusion performed in the prone position with double lung ventilation to a posterior spinal fusion and instrumentation (PSFI) for severe idiopathic scoliosis. SUMMARY OF BACKGROUND DATA.: A prone thoracoscopic anterior release (TAR) offers the advantages of a minimally invasive approach, without requiring repositioning for the PSFI, and has significantly less acute pulmonary complications since single lung ventilation is avoided. It is unclear whether prone thoracoscopy adversely affects pulmonary function tests (PFT) when added to a PSFI for severe deformity. METHODS.: A prospective consecutive series of patients from a single institution undergoing spinal deformity surgery were reviewed. Those patients who underwent prone TAR followed by PSFI were compared to patients who had PSFI alone. In addition, those patients who had a thoracoplasty and PSF (PSFI-T) were compared to those who had a TAR and PSFI with T. (PFTs were measured before surgery and 1, 3, 6 weeks, 3 and 6 months, and 1 year after surgery. Forced vital capacity (FVC) and FE-1 parameters were compared to baseline levels for each patient. RESULTS.: There were 13 patients in the TAR + PSFI groups and 83 in the PSFI groups. The patients in the TAR + PSFI group had larger thoracic curves (83.2° vs. 59.7°), greater correction (59.4% vs. 50.1%) (P = 0.07), and greater increase in thoracic height (16.4% vs. 6.8%) following surgery. (P < 0.05) PFTs declined more rapidly for the TAR + PSFI patients in the first 3 weeks, however, improved rapidly until 1 year when they were significantly better than the PSFI group for predicted FVC % (29.7% vs. 7.5% above baseline) and forced expiratory volume (FEV) 1% (28.5% and 8.9% above baseline). (P < 0.05) When a thoracoplasty was added to the procedure, the differences in PFTs between those who had a TAR and those who did not was not significant. The TAR + PSFI-T group had FVC % predicted of 5.3% above baseline compared to 4.3% above baseline for the PSFI-T group. The percent predicted FEV 1% was 10.4% above baseline for the TAR + PSFI-T group compared to 4.5% for the PSF-T group (P > 0.05). CONCLUSION.: When performing a prone thoracoscopic release for severe thoracic deformity, excellent coronal plane correction is achieved. There does not appear to be any detrimental effect on pulmonary function when a prone thoracoscopic release using double lung ventilation is added to a PSFI. This technique can be efficacious in achieving excellent deformity correction without adversely affecting pulmonary function and is recommended when treating severe spinal deformity. Adding a thoracoplasty provided a negative effect on pulmonary function and limited the benefits of performing a thoracoscopic release to the PSFI patients.