Surgical and long-term functional outcomes of patients with Duchenne muscular dystrophy following spinal deformity correction

Table 1 Summary demographics, and radiographic and operative details for patients with Duchenne muscular dystrophy and spinal deformity treated by posterior instrumented spinal fusion (mean ± SD)

Parameter (units)	Patient cohort
Number of patients (n)	43
Clinical/operative
Age at surgery (yr)	14.4 (± 1.6; 10.8-18.2)
Spinal deformity, n (%)
Scoliosis	33 (76.7)
Kyphoscoliosis	10 (23.3)
Single thoracolumbar curve	40 (93)
Double thoracic and lumbar curve	3 (7)
Gastrostomy for nutrition pre-operatively, n (%)	4 (9.3)
NIV pre-operatively, n (%)	5 (11.6)
Moderate left ventricular systolic dysfunction, n (%)	2 (4.6)
Operative time (minutes)	352.1 (± 72.7; 150-490)
Intraoperative blood loss (%; TBV)	36 (± 23.5; 12-150)
Distal fusion extent, n (%)
L4	4 (9.3)
L5	21 (48.8)
Pelvis	18 (41.9)
Length of stay in ICU (days)	6.5 (± 3.1; 3-17)
Length of stay in hospital (days)	14.1 (± 7.2; 7-30)
Postoperative complications, n (%)	11 (25.6)
Early wound infections	4 (9.3)
Removal of instrumentation (pelvic fixation)	1 (2.3)
Hepatotoxicity	4 (9.3)
Pneumonia	2 (4.6)
Preoperative radiographs
Scoliosis (Cobb angle; o)	57.5 (± 31; 10-120)
Scoliosis on traction radiographs (o)	32 (± 24; 0-92)
Scoliosis flexibility index (%)	52 (± 27.5; 7-100)
Pelvic obliquity (o)	16.3 (± 13.2; 0-46)
Pelvic obliquity on traction radiographs (o)	9.2 (± 9.3; 0-35)
Pelvic obliquity flexibility index (%)	58 (± 31; 0-100)
Thoracic kyphosis (T5-T12; o)	55.8 (± 28.1; 0-98)
Lumbar lordosis (T12-S1; o)	11.1 (± 20.3; 0-79)
Coronal balance (C7PL, cm)	3.8 (± 2.7; 0-12)
Sagittal balance (C7PL, cm)	6.1 (± 6.4; -11.4-1)
Postoperative radiographs
Scoliosis (Cobb angle; o)	15.6 (± 16.4; 0-60)
Scoliosis correction (%)	79.2 (± 18.6; 40-100)
Pelvic obliquity (o)	4.6 (± 6.4; 0-23)
Pelvic obliquity correction (%)	80.8 (± 25; 19-100)
Thoracic kyphosis (T5-T12; o)	33.7 (± 7.3; 20-55)
Lumbar lordosis (T12-S1; o)	35.8 (± 8.7; 20-55)
Coronal balance (C7PL, cm)	0.68 (± 1.1; 0-4.5)
Sagittal balance (C7PL, cm)	-0.18 (± 1.6; -4 to 5.4)

C7PL: C7 plumb line; NIV: Non-invasive ventilation; TBV: Total blood volume; ICU: Intensive care unit; L: Luque sublaminar wires.

Table 2 Aetiology of death during follow-up in patients with Duchenne muscular dystrophy after surgical correction of spinal deformity, n (%)

Cause of death	Number of patients
Respiratory failure	10 (41.6)
Pneumonia	7 (29.2)
Severe left ventricular systolic dysfunction	6 (25)
Tracheostomy bleeding	1 (4.2)

In our cohort of 43 patients with Duchenne muscular dystrophy who underwent surgical correction of spinal deformity, 24 patients died during follow-up due to respiratory failure, pneumonia, severe left ventricular systolic dysfunction, or tracheostomy bleeding.

Table 3 Muscular Dystrophy Spine Questionnaire results

Item	Question	Item mean score	SD	Range
	“Last week how difficult was it to…”
1	Get dressed	0	0	0
2	Go to the toilet	0	0	0
3	Lean forward and reach out in front of me	1.06	1.34	0-4
4	Move myself around in bed	0.5	0.8	0-2
5	Write (e.g., a short note and sign it)	1.06	1.69	0-4
6	Do up my zipper	0	0	0
7	Sit up in bed	1.93	1.52	0-4
8	Lift my arms to reach	0.8	1.25	0-4
9	Lift my head when lying down	0.9	1.18	0-4
10	Transfer or move from one position to other	0.4	0.89	0-3
11	Use both hands (e.g., put toothpaste on my toothbrush)	0.8	1.16	0-4
12	Use 1 arm and hand for balance while reaching in front with the other hand	0.75	1.12	0-4
13	Hold a spoon or fork by myself as part of a meal	0.8	1.47	0-4
14	Lift a cup/glass to my mouth by myself to drink	0.68	1.25	0-4
15	Sit comfortably in a good position, in my wheelchair all day	2.06	1.61	0-4
16	Shift weight or change my hip position in my wheelchair	0.68	1.01	0-3
17	Use the computer	2	1.46	0-4
18	Finish brushing my teeth	0.56	1.15	0-4
19	Change my arm position in my arm rests	1.18	1.51	0-4
20	Turn to reach for something	0.5	1.09	0-4
21	Bend forwards to eat	1	1.36	0-4
22	Sit in my chair all day without breaks	2	1.86	0-4
23	Sleep comfortably in bed	2.375	1.6	0-4
24	Sit at the table for meals	3	1.3	0-4
25	Bend forward to drink from a straw	1.43	1.67	1-4
26	Keep balance while sitting in my wheelchair	3	1.31	0-4
27	Look good while sitting in my wheelchair	3	1.46	0-4
	“Last week, how bad was…”
28	Pain in my hips or back last week	3.125	1.2	0-4
29	Me being out of breath last week	2.43	1.8	0-4
	Total score	38.1	25.9	1-100

Items 1-27 are rated 0-4 (0: I can’t do it at all; 1: Very difficult; 2: Moderately difficult; 3: A little difficult; 4: Not difficult); items 28 and 29 are rated 0-4 (0: Extremely bad; 1: Very bad; 2: Bad; 3: A little bit bad; 4: Not a problem). Results of the Muscular Dystrophy Spine Questionnaire (16) completed by patients (n = 16) with Duchenne Muscular Dystrophy at long-term follow-up after surgical correction of scoliosis (mean follow-up: 11 years).

Table 4 Correlation between clinical, operative, and both preoperative and postoperative radiographic variables with patient-reported Muscular Dystrophy Spine Questionnaire total scores: Quantitative clinical, operative and radiographic variables were assessed for correlation with Muscular Dystrophy Spine Questionnaire total scores by linear regression analysis; standardised coefficients are displayed

Clinical/radiological variable	Value/coefficient estimate (95%CI)	P value
Clinical/Operative parameters
Postoperative follow-up (yr)	-0.766 (-1.138, -0.394)	0.001a
Age (yr)	-0.651 (-1.086, -0.216)	0.006a
Age at loss of independent ambulation (yr)	0.496 (0.127, 0.865)	0.013a
Age at surgery (yr)	-0.146 (-0.519, 0.227)	0.410
Preoperative gastrostomy (Y/N)1	-0.036 (-1.072, 1.001)	0.941
Preoperative NIV use (Y/N)1	0.110 (-0.731, 0.951)	0.777
Duration of surgery (minutes)	-0.030 (-0.603, 0.543)	0.911
Intraoperative blood loss (%, TBV)	-0.297 (-0.841, 0.247)	0.257
Instrumented fused to pelvis (Y/N)1	0.542 (-0.221, 1.306)	0.145
Length of ICU stay (days)	0.123 (-1.010, 1.255)	0.817
Length of stay in hospital (days)	-0.535 (-1.663, 0.593)	0.322
Postoperative complications (Y/N)1	0.010 (-0.703, 0.723)	0.975
Preoperative radiographic parameters
Scoliosis (Cobb angle) (°)	0.268 (-5.330, 5.867)	0.907
Scoliosis on traction radiographs (Cobb angle)	-2.771 (-9.706, 4.164)	0.351
Scoliosis flexibility index (%)	-2.797 (-6.952, 1.359)	0.144
Pelvic obliquity (°)	-0.531 (-4.784, 3.723)	0.761
Pelvic obliquity on traction radiographs (°)	1.036 (-4.511, 6.582)	0.651
Pelvic obliquity flexibility index (%)	1.368 (-2.465, 5.200)	0.401
Lumbar lordosis (T12-S1; °)	0.346 (-1.880, 2.571)	0.706
Thoracic kyphosis (T5-T12; °)	0.153 (-2.283, 2.589)	0.878
Sagittal balance (C7PL, cm)	0.533 (-1.041, 2.106)	0.424
Coronal balance (C7PL, cm)	0.213 (-1.401, 1.828)	0.748
Postoperative radiographic parameters
Scoliosis (Cobb angle) (°)	-3.005 (-4.718, -1.292)	0.004a
Correction of scoliosis (%)	2.167 (1.053, 3.282)	0.002a
Pelvic obliquity (°)	0.367 (-0.765, 1.499)	0.468
Correction of pelvic obliquity (%)	0.433 (-0.263, 1.129)	0.185
Lumbar lordosis (T12-S1; °)	-0.642 (-1.184, -0.100)	0.027a
Thoracic kyphosis (T5-T12; °)	0.043 (-0.345, 0.430)	0.802
Sagittal balance (C7PL, cm)	-0.190 (-0.768, 0.389)	0.464
Coronal balance (C7PL, cm)	0.886 (-0.215, 1.987)	0.099

¹Indicates qualitative variable.

^aIndicates statistically significant result (P < 0.05).

L: Luque sublaminar wires; C7PL: C7 plumb line; NIV: Non-invasive ventilation; TBV: Total blood volume; ICU: Intensive care unit.

Table 5 Clinical and radiographic outcomes of surgical correction of scoliosis in patients with Duchenne muscular dystrophy, the current and previous studies reporting clinical and radiographic outcomes are summarized

Study	Current	Heller	Sengupta		Marsh	Cervellati	Hahn	Mehta	Modi	Takaso	Debnath		Alexander	Duckworth	Suk	Nedelcu	Scannell		Takaso	Yang
Year	2022	2001	2002		2003	2004	2008	2009	2010	2010	2011		2013	2014	2014	2016	2017		2018	2020
Patients (n)	43	31	50		30	20	20	36	18	28	22	18	28	26	40	13	47	13	271	99
Instrumentation (n)	PH/PS/SL or PS	I	L/G or L-rod	L/G or L-rod	C/HL/USS/S	L/CD	PS/G	PS	PS	PS	SL	PS	L/G and/or PS	SL or PS	CD	UR	L	PS	PS	CD
Distal instrumented level [n = (if subset)]	L4 (21), L5 (4), P (18)	SP	P (31)	L5 (19)	P	SP	P	L5 (26); P (10)	L5 (7); SP (11)	L5	P	L5	NA	L4/5 (14); SP (12)	LL (5); P (40)	SP	P	P	L5	LL (5); P (94)
Age at surgery (yr)	14.4	14.1	14	11.7	14.7	13	14	13.5	14.4	13	12.5	11.8	14.2	14.2	14.9	12.7	13	14	13.5	15.1
Pre-op FVC%	NA	54.3	44	58	33	NA	55	NA	NA	NA	57	53	NA	NA	NA	NA	59	48	NA	NA
Post-op FVC%	NA	NA	NA	NA	NA	NA	54	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA
FVC% at final F/U	NA	52.7	NA	NA	NA	NA	47	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA
Pre-op scoliosis (°)	57.5	48.6	48.4	19.8	61	48	44	71	76.4	74	45.3	42.8	56.4	59	65.5	30	31	43	70	65.8
Scoliosis (initial post-op) (°)	NA	12.5	16.7	3.2	24.2	22	10	25.5	30.1	14	NA	NA	21.6	13	NA	2	16	12	15	NA
Correction of scoliosis (%)	79.2	74.3	66	80	60.3	54.2	77	65	63.3	81	NA	NA	61.7	78	NA	93.3	NA	NA	78.6	50.6
Scoliosis at final F/U (°)	15.6	12.5	22	5.2	NA	28	9	28.5	31.3	17	17.7	7.3	NA	NA	36.2	4.2	21	12	17	32.5
Scoliosis loss of correction (°)	NA	0	5.2	2	NA	6	1	3	1.2	3	NA	NA	NA	NA	NA	2.2	5	0	2	NA
Pre-op pelvic obliquity (°)	16.3	18.2	19.8	8.9	18.1	19.8	14	14.8	18.1	9	14.5	11.2	NA	21	20.7	7.7	7	6	15	21
Pelvic obliquity (initial post-op) (°)	NA	3.8	7.2	2.2	NA	10	3	6.7	8.6	3	NA	NA	NA	3	NA	0.6	5	3	5	NA
Correction of pelvic obliquity (%)	80.8	79.1	63.6	76	NA	49.5	65	54.7	52	66.7	NA	NA	NA	85.7	NA	92.2			66.7	53.8
Pelvic obliquity at final F/U (°)	4.6	5.1	11.6	2.9	NA	NA	3	9.3	8.8	6	5.6	2	NA	NA	11.4	1.5	5	2	6	9.7
Fusion to sacropelvis (%)	41.9	100	100	0	100	100	100	27.8	66.7	0	100	0	NA	46.2	89.9	100	100	100	0	94.9
Duration of surgery (min)	352.1	363	310	240	212	180	307	332	348	282	260	216	NA	260	NA	170	227	332	270	NA
Blood loss (mL or % TBV)	36%	3373	4100	3300	4900	1200	2642	2955	2561	950	3400	2000	NA	1882	NA	2553	1327	1596	910	NA
F/U (yr)	10.9	1.8	4.6	3.5	Until discharge	5	5.2	1.6	1.4	3.3	4.5	2.3	1	2	3.86	6.9	4	4	3	6.6
MDSQ score at F/U	38.1	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	NA	35.1	NA	NA	NA	NA	NA

¹This cohort included 20 Duchenne muscular dystrophy patients and 7 patients with spinal muscular atrophy.

C: Colorado; CD: Cotrel-Dubousset; FVC: Forced vital capacity; F/U: Follow-up; G: Galveston technique; H: Harrington; HL: Harrington-Luque; L: Luque sublaminar wires; LL: Lower lumbar; MDSQ: Muscular Dystrophy Spinal Questionnaire; P: Pelvis; PH: Pedicle hooks; PS: Pedicle screws; S: Synergies; SL: Sublaminar instrumentation; SP: Sacropelvis; USS: AO universal spine system; NA: Not available; TBV: Total blood volume; NA: Not available.

Table 6 Complications and hospital stay outcomes following surgical correction of scoliosis in patients with Duchenne muscular dystrophy; the current and previous studies reporting complications and hospital stay outcomes are summarised

Study	Current	Heller	Sengupta		Marsh	Cervellati	Hahn	Mehta	Modi	Takaso	Debnath		Alexander	Duckworth	Suk	Nedelcu	Scannell
Year	2022	2001	2002		2003	2004	2008	2009	2010	2010	2011		2013	2014	2014	2016	2017
Patients (n)	43	31	50		30	20	20	36	18	28	22	18	28	26	40	13	47	13
Instrumentation (n)	PH/PS/SL or PS	I	L/G or L-rod	L/G or L-rod	C/HL/USS/S	L/CD	PS/G	PS	PS	PS	SL	PS	L/G and/or PS	SL or PS	CD	UR	L	PS
Distal instrumented level (n)	L4 (21), L5 (4), P (18)	SP (31)	P (31)	L5 (19)	P (30)	SP (n = 20)	P (n = 20)	L5 (26), P (10)	L5 (7), SP (11)	L5 (28)	P (22)	L5 (18)	NA	L4/5 (14), SP (12)	LL (5), P (40)	SP (13)	P (47)	P (13)
ICU stay (days) (patient, n)	6.5	3	NA	NA	NA	2	3.2	0.4 (n = 10)	0.45 (n = 4)	NA	2.3	1.8	NA	4.5	NA	NA	2	4
Hospital stay (days)	14.1	21	16.7	7.7	22	NA	19	17.9	19	NA	8.5	7	NA	13	NA	NA	7	7
Complications (%; n)	25.6%; WIRI (4), ROPI (1), pn (2), hep (4)	D (5%), pu (24%), instr 10%, WHP (28%), GI (23%), Thr (5%), Bl (5%)	16%; DIAR (1), RI (4)	10.5%; DIARI (1); RI (1)	30%; PE (1), REI (4), CA (1), TR (2), LFT (1), Pn (2), WI (2)	30%; CA (1), NB (1), SPS (1), Instr (3)	20%; D (1), PO (1), WHP (1), DIARI (1)	47%; D (1), Instr (3), Co (7), PI (6)	48.1%; D (CA; 1), UTI (2), Co (6), HT (3), TIL (1), AT (2), CBP (2), Instr (1)	17.9%; I (5)	54.5%; Bl (2), WI (5), PRS (3), Instr (2)	16.7%; WI (2), Instr (1)	17.8%; WI (3), An (2)	38.5%; WI (6), Hep (4), GI (2), Pn (2)	52.5%; Pu (20), WI (1)	53.8%; WHP (3), WI (2), Instr (2),	68%; Instr (12), Inf (2)	54%; PJK (1), WI (3)

C: Colorado; CD: Cotrel-Dubousset; FVC: Forced vital capacity; G: Galveston technique; H: Harrington; HL: Harrington-Luque; L: Luque sublaminar wires; LL: Lower lumbar; P: Pelvis; PS: Pedicle screws; S: Synergies; SL: Sublaminar instrumentation; SP: Sacropelvis; USS: AO universal spine system; NA: Not available. Complications abbreviations: An: Aneamia; AT: Atelectasis; Bl: Bleeding; CA: Cardiac arrest; CBP: Convex back pain; Co: Coccygodynia; D: Death; DIAR: Deep infection and reinstrumentation; DIARI: Deep infection and removal of instrumentation; GI: Gastrointestinal; Hep: Hepatotoxicity; HT: Haemothorax; I: Ileus; Inf: Infections (not categorised); Instr: Instrumentation complication/failure; LFT: Abnormal liver function tests; NB: Neurogenic bladder; PE: Pleural effusion; PI: Prominent instrumentation; PJK: Proximal junction kyphosis; Pn: Pneumonia; PO: Pulmonary oedema; PRS: Prolonged respiratory support; Pu: Pulmonary; REI: Reintubation; RI: Revision of instrumentation; ROPI: Removal of prominent instrumentation; SPS: Sacral pressure sore; Thr: Thrombosis; TIL: Tingling in legs; TR: Tracheostomy; UTI: Urinary tract infection; WHP: Wound healing problems; WI: Wound infection; WIRI: Wound infection and retention of instrumentation; NA: Not available.