Bell et al (1994) studied the result of multiple-level thoracic and lumbar 
laminectomy, a corrective spinal surgery commonly performed on children. 
The data in the study consist of retrospective measurements on 83 patients. The
specific outcome of interest is the presence (1) or absence (0) of kyphosis, defined 
as a forward flexion of the spine of at least 40 degrees from vertical. The
available predictor variables are Age in months at time of the operation, the 
starting of vertebrae levels involved in the operation (StartVert), and the
number of levels involved (NumVert). The goal of this analysis is to identify 
risk factors for kyphosis. 


From the set of 83 patients cases 15 and 28 are removed.

Col 1 = Age = months at the time of operation
Col 2 = Start = starting thoracic vertebrae (1-12), lumbar veretbrae (13-18).
Col 3 = Num = number of vertebrae
Col 4 = Kyphosis = 1 if present, 0 if absent


71	5	3	0
158	14	3	0
...
36	13	4	0

Bell DF, Walker JL, O'Connor G, Tibshirani R. Spinal deformity after multiple-level
cervical laminectomy in children. Spine 1994;19(4):406-11.