ROTATION ASSESSMENT IN ADOLESCENT IDIOPATHIC SCOLIOSIS WITH ROD DEROTATION

Adolescent idiopathic scoliosis (AIS) is characterized by rotational and lateral deformity of the spine. The measurement of vertebral rotation is important for prognosis and treatment. Our objective was to evaluate whether the Nash-Moe method can be used to measure axial deformity correction with surgical treatment using the rod derotation maneuver at both the apex and extremities of the deformity in patients with AIS.

Methods:

Rotation was assessed using the Nash and Moe criteria, on preoperative and postoperative radiographs. We also evaluated the severity on the coronal plane using the Cobb method, ratio of correction achieved, screw density, and number of vertebrae involved in the instrumentation.

Results:

The Cobb method correction average was 54.8%. When we disregarded vertebrae that presented preoperative Nash-Moe grade 0, the average measurable correction was 54.5% in the first non-instrumented vertebra above, 69.2% in the first instrumented vertebra, 32.2% in the apical vertebra, 36.8% in the last instrumented vertebra, and 30% in the first non-instrumented vertebra below. In our study, 32.14% of the patients presented a measurable correction in the apical vertebra.

Conclusion:

On the axial plane, correction can be satisfactorily evaluated using the Nash-Moe method. Level of Evidence VI. Case Series.

Keywords:
Scoliosis; Deformity; Spine

	average	Variation	IC 95%
Age	14.5 years	11-17	13.7-15.3
Preoperative Cobb	78.3°	46-121	71.9-84.7
Postoperative Cobb	36.3°	15-73	30.1-42.4
Curve correction	54.8%	29-71	49.7-59.9
Screw Density	74.6%	58-100	70.5-78.6
Screw density at apex	62%	16-100	54.4-69.5
Number of vertebrae involved in arthrodesis	11.9	7-15	11.1-12.7

	Nash-Moe
	0	1	2	3	4
Vertebra not instrumented above	60.7%	32.1%	7.2%	0	0
First instrumented vertebra	53.6%	39.3%	7.1%	0	0
Apical vertebra	0	14.3%	32.1%	42.9%	10.7%
Last instrumented vertebra	32.1%	42.9%	25%	0	0
Vertebra not instrumented below	64.3%	32.1%	3.6%	0	0

	Nash-Moe
	0	1	2	3	4
Vertebra not instrumented above	75%	25%	0	0	0
First instrumented vertebra	67.9%	32.1%	0	0	0
Apical vertebra	3.6%	25%	32.1%	32.1%	7.1%
Last instrumented vertebra	50%	32.1%	17.9%	0	0
Vertebra not instrumented below	75%	21.4%	3.6%	0	0

	Post
Pre	0	1	2	3	4
0	0	0	0	0	0
1	1 (25%)	3 (75%)	0	0	0	p < 0.05
2	0	3 (33.3%)	6 (66.7%)	0	0	p < 0.05
3	0	1 (8.3%)	3 (25%)	8 (66.7)	0	p < 0.05
4	0	0	0	1 (33.3%)	2 (66.7%)	p < 0.05
Total	1	7	9	9	2	28

	Relative Correction by Nash-Moe Grade					Total Correction per Vertebra Measured
Preoperative Nash-Moe grade	0	1	2	3	4

Vertebra not instrumented above	0	44.4%	100%	0	0	21.4%
First instrumented vertebra	0	36.4%	100%	0	0	21.4%
Apical vertebra	0	0	33.3%	33.3%	33.3%	32.2%
Last instrumented vertebra	0	41.7%	28.6%	0	0	25%
Vertebra not instrumented below	0	33.3%	0	0	0	10.7%

	Relative Correction by Nash-Moe Grade				Total Correction per Vertebra Measured
Preoperative Nash-Moe grade	1	2	3	4

Vertebra not instrumented above	44.4%	100%	0	0	54.5%
First instrumented vertebra	36.4%	100%	0	0	69.2%
Apical vertebra	0	33.3%	33.3%	33.3%	32.2%
Last instrumented vertebra	41.7%	28.6%	0	0	36.8%
Vertebra not instrumented below	33.3%	0	0	0	30%

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[1] Correspondence: Fernando Flores de Araujo, Rua Dr. Ovídio Pires de Campos, 333 Cerqueira César, São Paulo, SP 05403-010. fernando_araujo87@hotmail.com