Abstract
Background: The long term survival of patients with type II and III spinal muscular atrophy differs considerably from patients with Duchenne muscular dystrophy. Despite this, treatment of scoliosis in both groups is often reported together1. There are only sporadic reports, all with small numbers, of combined anterior and posterior (two stage) scoliosis surgery in patients with spinal muscular atrophy (SMA)1. The aim of the current study was to document the peri-operative morbidity, length of stay and correction of deformity in patients with SMA that had two stage surgery and compare them with the patients that had single stage surgery.
Methods: A retrospective analysis of data on our consecutive series of patients with SMA.
We analysed the data of 31 patients with SMA (16M:15F) who underwent scoliosis surgery between 1996 and 2004. The data collected included SMA type, age at surgery, percentage predicted forced vital capacity(%PFVC), blood loss, duration of surgery, complications, type of surgery undertaken, pre-operative mean Cobb angle ± SD(including bending film Cobb angle ± SD), post-operative Cobb angle ± SD and length of hospital stay. The decision to do single or two stage surgery was based on the history of recurrent chest infection, %PFVC and the stiffness of the curve. Percentage correction of Cobb angle in patients that had two stage surgery compared with those that had single stage posterior surgery. Comparison of post-operative respiratory complications, estimated blood loss, total hours in theatre and mean length of stay between the two groups.
Results: There were 27 SMA type II and 4 SMA type III’s with a mean age at surgery of12.5 years (range 7.8 – 17.4). The mean pre-operative Cobb angle of all 31 patients was 89.7° ± 19.7°, the mean bending preoperative Cobb angle was 54° ± 13.3° and the mean post-operative Cobb angle was 33.7° ± 17.3°. Eighteen patients had single stage surgery and 13 had two stage surgery. Twelve out of the thirteen two stage operations had either a thoracotomy or a thoracoabdominal approach. In the patients that had single stage posterior surgery, the mean bending preoperative Cobb angle was 54° ± 13.3° and the mean post-operative Cobb angle was 38.7° ± 19.2°. In the patients that had two stage surgery the mean pre-operative bending Cobb angle was 53.6° ± 11.6° and the post-operative Cobb angle was 25.5° ± 10.8°. The %PFVC in the patients that had single stage and two stage surgery was 39.2 ± 12.8 and 69.2 ± 12.2 respectively. There were 3 respiratory complications in the single stage group and 4 in the two stage group. The average total estimated blood loss (EBL) in the single stage and two stage groups (first and second stage EBL’s combined) were 2433ml and 1902ml respectively. The length of stay for the patients with single stage surgery and two stage surgery was 14.1 ± 4.1 and 18.5 ± 7.4 days respectively. The total surgical hours for the patients with single and two stage surgery were 2.9 ± .6 hrs and 4.8 ± 1.2 hrs respectively.
Conclusion: The results of our series would suggest that in a selected group of SMA patients (no history of recurrent chest infection and an acceptable %PFVC) a better immediate deformity correction can be attained with two stage surgery. This has to be weighed up with a greater total EBL and mean length of stay for the patients that had two stage surgery.
The abstracts were prepared by Mr Colin E. Bruce. Correspondence should be addressed to Colin E. Bruce, Consultant Orthopaedic Surgeon, Alder Hey Children’s Hospital, Eaton Road, Liverpool, L12 2AP.
References:
1 Process measures and patient/parent evaluation of surgical management of spinal deformities in patients with progressive flaccid neuromuscular scoliosis (Duchenne’s muscular dystrophy and spinal muscular atrophy). Bridwell KH, Baldus C, Iffrig TM, Lenke LG, Blanke K. Spine1999 Jul 1;24(13):1300–9 Google Scholar
