Scoliocorrector Fatma-UI for correction of adolescent idiopathic scoliosis: Development, effectivity, safety and functional outcome

Table 1 Concept of developing Scoliocorrector Fatma-UI

Need	Principle	Method
High failure load	Fixation of vertebrae using gold standard in spine surgery	Pedicle screw fixation
Good coronal correction	Long medial translation	Wire pulls from outside of the body
Good rotational correction	The correction axis should be anterior to the rotational axis of scoliosis	Pedicle screw fixation as it reaches to anterior corpus
	Long posteromedial translation	Wire pulls from outside of the body
Good sagittal correction	The pulling point height can be adjusted to a normal sagittal profile	Pulling board to accommodate height adjustment of pulling point
	Long posterior translation	Wire pulls from outside of the body
Low correction force	Mechanical advantages	Moveable pulley
Optimal pulling vector	The pulling vector could be adjusted	Moveable pulley
Controllable correction	Gradual correction	Screw threads to control gradual correction
Efficient	Correction could be maintained	Screw threads to maintain correction
Low risk of neurological injury due to sublaminar fixation	Others fixation anchor	Pedicle screw fixation
Low risk of neurological injury due to medial breaching	Avoid derotation of screws toward spinal canal	Wire pulls to the lateral vertebral canal
No risk of foreign body reaction	No extra implant	Removal of tools after correction is achieved

Table 2 Baseline charactersitics of the subjects

Characteristic	Intervention group, n = 21	Control group, n = 23	P value
Clinical
Age - yr, mean (SD)	15.92 (0.35)	15.73 (1.51)	0.331
Sex
Male	2 (9.52)	4 (17.39)	0.672
Female	19 (90.48)	19 (82.61)
Body height - cm, mean (SD)	155.24 (7.52)	157.48 (6.1)	0.141
Body weight - kg, mean (SD)	44.11 (5.66)	47.95 (6.78)	0.021
Radiological
Cobb angle - degree, mean (SD)	57.19 (6.78)	62.58 (8.51)	0.011
Sagittal angle - degree, mean (SD)	17.7 (6.7)	20.08 (9.71)	0.181
Rotational angle - degree, mean (SD)	14.76 (6.73)	19.42 (7.81)	0.021
Sagittal profile
Hypokyphosis	14 (66.67)	12 (52.17)	0.332
Normokyphosis	7 (33.33)	11 (47.83)
Functional
SRS score - 22, mean (SD)	70.14 (6.81)	68.61 (6.85)	0.231
Function domain, mean (SD)	4.13 (0.29)	4 (0.47)	0.131
Pain domain, mean (SD)	3.55 (0.54)	3.61 (0.64)	0.381
Self-image domain, mean (SD)	2.47 (0.6)	2.42 (0.59)	0.371
Mental health domain, median (range)	4 (3-5)	3.6 (3-4.6)	0.413

Data are , n (%) unless otherwise indicated.

¹Unpaired t-test.

²Fischer test.

³Mann - Whitney test.

SD: Standard deviation.

Table 3 Postoperative characteristics of subjects

Characteristic	Intervention group, n = 21	Control group, n = 23	P value
Clinical
Body height - cm, mean (SD)	159.28 (7.73)	161.13 (6)	0.191
Body weight - kg, mean (SD)	44.19 (5.1)	48 (6.86)	0.021
Radiological
Cobb angle - degree, mean (SD)	16.28 (10.36)	20.79 (8.72)	0.061
Coronal correction - percent, mean (SD)	71.92 (17.55)	67.39 (17.55)	0.161
Sagittal angle - degree, mean (SD)	20.16 (4.75)	20.32 (6.63)	0.531
Rotational angle - degree, mean (SD)	11.59 ± 7.46	18.23 ± 6.39	0.0011
Sagittal profile
Hypokyphosis	11 (52.38)	10 (43.49)	0.562
Normokyphosis	10 (47.62)	13 (56.52)
Functional
SRS-22 score, median (range)	63 (50-84)	68 (43-79)	0.623
Function domain, mean (SD)	1.81 (0.41)	1.94 (0.42)	0.171
Pain domain, mean (SD)	2.68 (0.56)	2.67 (0.58)	0.481
Self-image domain, median (range)	3.4 (2.4-4.6)	3.6 (1.8-4.4)	0.833
Mental health domain, mean (SD)	3.21 (0.68)	3.37 (0.74)	0.231
Satisfaction, median (range)	4.5 (4-5)	4.5 (3-5)	0.43

Data are , n (%) unless otherwise indicated.

¹Unpaired t-test.

²Fischer test.

³Mann - Whitney test.

SD: Standard deviation.