Clinical significance of cervical MRI in brachial plexus birth injury

Figures & data

Figure 1. Coronal (A) and axial (B) BFFE MR images (0.5 mm) in a 3-month-old boy (patient 18) with brachial plexus birth injury on the right side. Total (both ventral and dorsal roots) avulsion of right C6 root with a PMC (asterisk): ventral root is avulsed from the cord (upper arrow), where a short stump of dorsal root is seen (lower arrow). Left ventral and dorsal C6 roots (arrowheads) are normal.

Figure 2. Axial BFFE MR image (0.5 mm) in a 4-month-old girl (patient 26) with brachial plexus birth injury on the right side. Partial avulsion of C8 root: ventral root is avulsed (red arrow), dorsal C8 root is intact (arrowhead). Left C8 nerve roots are normal (arrowheads).

Figure 3. Coronal BFFE image (0.5 mm) in a 3-month-old girl (patient 16) with brachial plexus birth injury on the right side. Right ventral C6 root is thinned (arrow) compared to the normal left ventral C6 root (arrowhead).

Figure 4. Coronal (A) and axial (B) BFFE image (0.5 mm) in 3-month-old boy (patient 31) with brachial plexus birth injury on both sides. (b) Intact ventral and dorsal nerve roots (red arrows) at C7 level despite a PMC clearly visible on both sides.

Table 1. Patient demographics. Patients are arranged in descending order of abnormal findings on MRI

Findings at birth		MRI findings^b					Plexus reconstruction
Patient	Extent of injury^a	3-month test score	Age (months)	Total root avulsion	Partial root avulsion	Thinning of roots	PMC	Age (months)	Plexus reconstruction	Converted to SAN pro SSN
8	FUE^c	0	0.9	C6–8		C5vd	C5–8	6.6	CC7
25	FUE	0	2.7	C8–T1			C8–T1	4.3	yes
15	FUE^c	0.3	2.6	C8–T1			C8–T1	3.4	yes
34	CP	2.1	2.5	C7–8			C7–8		refused
22	CP	2.8	3.2	C7–8			C7–T1	7.4		yes
3	FUE	0	4.0	C8			C8		refused
32	FUE^c	^d	0.3	C8			C7–T1	0.8	yes
9	FUE	0	3.4	C8			C8	4.4	yes
20	FUE	1.3	4.0	C8	C7D		C8–T1	5.6	yes
24	CP	1.8	3.7	C8			C8	5.7	yes
13	FUE	2.6	14.3	C7			C7	27.9		yes
18	CP	3.2	3.0	C6			C6	7.3	yes
17	FUE	0.6	1.9					3.9	yes
11	CP	1.2	4.6					6.6	yes
21	FUE^c	1.3	3.9					9.0	yes
1	CP	2.1	6.4		C6V, C8V		C6 8		refused
26	CP	2.4	4.5		C8V	C7vd	C8	5.6	yes
10	CP	3.8	3.3		C8V		C8
14	UP	4.8	7.1		C6V		C6	8.0		yes
28	UP	4.5	3.9		C6D	C6v	C6
16	CP	4.8	3.9		C6D	C6v
31	UP	3.8	3.5				C5 6 7
19	UP	4.8	7.7				C8
27	CP	2.5	3.9					4.8		yes
29	CP	4.2	3.2
23	CP	4.5	4.4
6	UP	4.8	3.2
33	UP	5.2	4.3
30	CP	5.2	3.9
2	CP	5.5	4.6
7	UP	5.8	3.4
4	UP	5.8	4.7
5	UP	5.8	4.1
12	UP	5.8	1.7

a FUE = Flail upper extremity, CP = Complete plexus involvement, UP = Upper plexus involvement,

b V = Ventral root, D = Dorsal root, v = Ventral root thinning, d = Dorsal root thinning, SAN = Spinal accessory nerve, SSN = Supra-

scapular nerve.

c Horner sign.

d Primary surgery before 3 months of age

Figure 5. Multivariable model expressing GSA difference in relation to age at time of MRI and clinical findings at birth.

Table 2. Glenohumeral joint (GHJ) MRI findings. Patients are arranged primarily in descending order based on incongruency of their affected shoulder, secondarily in descending order based on the difference between GSA of both shoulders

Patient	Findings at birth^a	MRI age (months)	GHJ	Glenoid shape	GSA (°)affected	GSA (°)normal	GSA difference
19	UP	7.7	D	PG	–40	–5	35
11	CP	4.6	D	PG	–40	–6	34
14	UP	7.1	D	PG	–40	–6	34
5	UP	4.1	D	PG	–30	–3	27
3	FUE	4.0	D	PG	–25	3	22
10	CP	3.3	D	PG	–25	–8	17
16	CP	3.9	D	PG	–25	–20	5
26	CP	4.5	SL	PR	–40	–15	25
1	CP	6.4	SL	PR	–30	–9	21
21	FUE	3.9	SL	PR	–25	–5	20
4	UP	4.7	SL	PR	–40	–22	18
24	CP	3.7	SL	PR	–25	–10	15
9	FUE	3.4	SL	PR	–30	–20	10
6	UP	3.2	SL	PR	–25	–15	10
30	CP	3.9	SL	N	–20	–10	10
27	CP	3.9	N	N	–15	–3	12
23	CP	4.4	N	N	–20	–8	12
17	FUE	1.9	N	N	–20	–10	10
33	UP	4.3	N	N	–20	–11	9
7	UP	3.4	N	N	–20	–12	8
28	UP	3.9	N	N	–15	–8	7
15	FUE	2.6	N	N	–13	–7	6
28	CP	3.0	N	N	–13	–7	6
32	FUE	0.3	N	N	–15	–10	5
34	CP	2.5	N	N	–15	–10	5
22	CP	3.2	N	N	–10	–6	4
29	CP	3.2	N	N	–5	–1	4
8	FUE	0.9	N	N	–9	–6	3
13	FUE	14.3	N	N	–7	–10	3
2	CP	4.6	N	N	–8	–5	3
25	FUE	2.7	N	N	–5	–7	2
20	FUE	4.0	N	N	–5	–4	1
12	UP	1.7	N	N	–5	–5	0
31	UP/UP	3.5	N/N	N/N	–15/–20

a See Table 1.

D = Dislocated, SL = Subluxed, N = Normal, PG = Pseudoglenoid,

PR = Posteriorely rounded

Table 3. MRI findings compared to intra-operative findings by root level

C5

C6

C7

C8

T1

PMC

Patient

MRI

Surgery

MRI

Surgery

MRI

Surgery

MRI

Surgery

MRI

Surgery

MRI

9

N

N

N

N

N

N

A

A

N

—

Yes

11

N

N

N

N

N

—

N

—

N

—

No

15

N

N

N

N

N

N

A

A

A

A

Yes

17

N

N

N

N

N

N

N

N

N

—

No

18

N

N

A

A

N

N

N

—

N

—

Yes

20

N

N

N

N

D

—

A

—

N

—

Yes

21

N

N

N

N

N

N

N

—

N

—

No

24

N

N

N

N

N

N

A

—

N

—

Yes

25

N

N

N

N

N

N

A

A

A

A

Yes

26

N

N

N

N

v + d

N

V

N

N

—

Yes

32

N

N

N

N

N

A

A

A

N

—

Yes

N = Normal, A = Avulsion, V = Ventral root avulsion, D = Dorsal root avulsion,

v = Ventral root thinning, d = Dorsal root thinning, — = Not examined

True positive was defined as a total root avulsion seen on MRI and detected during exploration. True negative was defined as no avulsion seen on MRI nor detected during surgery. Partial and thinned roots seen on MRI as well as roots not explored during surgery were left out of the calculation.

Table 4. Patient outcome. Outcome expressed as ratio (%) of active antigravity range of motion of the affected side in comparison with the unaffected side. Patients are arranged primarily by the extent of injury at birth and secondarily by their 3-month Test Score

Outcome
Patient	Findings at birth ^a	3-month test score	Plexus surgery ^d	Nerve transfer	GHJ relocation	Other surgery	A	B	C	D	E	F	G
8	FUE ^b	0	CC7		yes	EIP > EPB,	8.0	CP	91	0	33	0	0
3	FUE	0	refused	SAN > AN		BR > EDC	8.6	CP	28	73	17	50	0
32	FUE ^b	^c	5 > 8, 6 > UT				2.6	CP	50	38	25	25	0
9	FUE	0	5–6 > UT, SAN > SSN	SAN > ISN	yes		7.3	CP	33	92	10	10	10
25	FUE	0	5 > 6, 6 > 1, 7 > 8, SAN > SSN			forearm	3.7	CP	36	50	10	40	20
						osteotomy
15	FUE ^b	0.3	5 > UT, 6 > MT, 7 > 81,				4.5	CP	50	63	72	0	10
			SAN > SSN
17	FUE	0.6	5–6 > UT, 7 > MT, SAN > SSN		yes		5.5	CP	50	75	11	20	10
11	CP	1.2	5–6 > UT, SAN > SSN				6.2	UP	44	28	61	100	100
21	FUE ^b	1.3	5–6 > UT, 7 > MT, SAN > SSN	Oberlin		FCU > ECR	5.0	CP	50	84	17	50	50
20	FUE	1.3	5–6 > UT, SAN > SSN			TM > IS	4.5	UP	78	88	100	100	100
24	CP	1.8	5 > UT, 6 > UT, 7 > MT,	Oberlin			4.2	UP	50	80	100	100	100
			SAN > SSN		yes
1	CP	2.1	refused				5.2	UP	40	100	100	100	100
34	CP	2.1	refused				1.6	UP	38	38	25	100	100
26	CP	2.4	6 > UT, SAN > SSN				3.2	UP	44	62	100	100	100
27	CP	2.5	converted to nerve transfer				3.0	UP	78	81	100	100	100
13	FUE	2.6	converted to nerve transfer	SAN > SSN			5.6	UP	39	63	56	100	100
				SAN > SNN,
22	CP	2.8	converted to nerve transfer	pRN > pAN			4.0	UP	38	75	61	100	100
18	CP	3.2	5 > 6, SAN > SSN	SAN > SSN			5.0	UP	83	88	100	100	100
10	CP	3.8					6.2	UP	69	81	100	100	100
31	UP	3.8		SAN > ISN			2.9	UP	89	81	100	100	100
29	CP	4,2		SAN > ISN			3.5	UP	72	81	100	100	100
28	UP	4.5		SAN > ISN			2.2	UP	89	97	100	100	100
23	CP	4.5					2.9	UP	89	91	100	100	100
14	UP	4.8	converted to nerve transfer				6.1	UP	66	90	100	100	100
6	UP	4.8		SAN > SSN	yes		5.2	UP	94	100	100	100	100
19	UP	4.8					4.5	UP	40	56	56	100	100
16	CP	4,8					4.0	UP	88	91	100	100	100
33	UP	5.2					2.4	UP	81	81	100	100	100
30	CP	5.2		SAN > ISN			3.2	UP	92	100	100	100	100
2	CP	5.5		SAN > ISN	yes	TM > IS	7.4	UP	60	87	100	100	100
7	UP	5.8			yes	TM > IS	6.9	UP	50	71	36	100	100
4	UP	5.8					2.1	UP	72	69	100	100	100
5	UP	5.8					8.4	UP	94	81	100	100	100
12	UP	5.8					4.8	UP	89	100	100	100	100

^aSee Table 1.

^bpositive Horner sign

^c primary surgery before 3 months of age

^dAN = Axillary nerve, pAN = partial axillary nerve, BR = Brachioradialis muscle, CC7 = contralateral C7 transfer, ECR = Extensor carpi radialis longus and brevis muscle, EDC = Extensor digitorum communis muscle, EIP = Extensor indicis proprius muscle, EPB = Extensor pollicis brevis muscle, FCU = Flexor carpi ulnaris muscle, IS = Infraspinatus muscle, ISN = Infraspinatus branch of suprascapular nerve, M = Middle trunk, pRN = partial Radial nerve, SAN = Spinal accessory nerve, SSN = Suprascapular nerve, TM = Teres major muscle, UT = Upper trunk