Clinical performance of a bone-anchored annular closure device in older adults

Figures & data

Figure 1 Rates of symptomatic (Symp) reherniation and reoperation over 3 years after lumbar discectomy by age group.

Figure 2 Risk of symptomatic reherniation over 3 years after lumbar discectomy with or without an annular closure device among older versus younger patients. The risk of symptomatic reherniation over 3 years was 30.2% (SE 3.1%) in younger controls, 21.1% (SE 9.4%) in older controls, 14.8% (SE 2.3%) in younger ACD patients, and 12.5% (SE 8.3%) in older ACD patients.

Abbreviation: ACD, annular closure device.

Figure 3 Risk of reoperation over 3 years after lumbar discectomy with or without an annular closure device among older versus younger patients. The risk of reoperation over 3 years was 26.3% (SE 10.1%) in older controls, 18.8% (SE 2.5%) in younger controls, 11.1% (SE 7.4%) in older ACD patients, and 11.0% (SE 2.0%) in younger ACD patients.

Abbreviation: ACD, annular closure device.

Figure 4 Percentage of patients who achieved the MCID without a reoperation over 3 years after lumbar discectomy with or without an annular closure device for each patient-reported outcome among patients under 60 years old (left panel)^a and patients at least 60 years old (right panel)^b. ^aAmong younger patients comparing ACD to controls, the rates were 80.4% vs 72.0% for leg pain, 81.9% vs 73.0% for ODI, 84.9% vs 75.1% for PCS, and 59.8% vs 46.5% for MCS. ^bAmong older patients comparing ACD to controls, the rates were 83.3% vs 70.6% for leg pain, 84.6% vs 70.6% for ODI, 83.3% vs 68.8% for PCS, and 53.8% vs 41.2% for MCS.

Abbreviations: ACD, annular closure device; Con, control; MCID, minimal clinically important difference; MCS, Mental Component Summary; ODI, Oswestry Disability Index; PCS, Physical Component Summary.

Table 1 Preoperative characteristics of older versus younger patients treated with lumbar discectomy^a

Characteristic	Age ≥60 (n=38)	Age <60 (n=512)	Difference (95% CI)	P-value
Age, years	65.0±4.0	41.9±9.2	23.1 (21.6, 24.6)	<0.001
Male sex	24 (63.2)	303 (59.2)	4.0 (−12.4, 18.1)	0.73
Body mass index, kg/m^2	26.7±4.0	26.2±4.1	0.4 (−0.9, 1.8)	0.55
Current smoker	9 (23.7)	235 (45.9)	−22.2 (−33.8, −6.1)	0.01
Lumbar (L1/L2 to L4/L5) herniation	27 (71.1)	214 (41.8)	29.3 (12.9, 41.9)	<0.001
Leg pain	84.8±13.1	80.5±14.9	4.2 (−0.7, 9.1)	0.09
Oswestry Disability Index	62.6±13.9	58.3±13.0	4.3 (0.0, 8.6)	0.05
Physical Component Summary score^b	27.4±7.0	28.9±6.0	−1.5 (−3.5, 0.5)	0.14
Mental Component Summary score^b	40.4±13.6	40.6±12.9	−0.2 (−4.5, 4.1)	0.94

Notes: ^aValues are mean ± standard deviation, or count (percentage); ^bScores derived from the SF-36 questionnaire.

Abbreviations: CI, confidence interval; SF-36, 36-Item Short Form Health Survey.

Table 2 Predictors of symptomatic reherniation and reoperation risk over 3 years after lumbar discectomy

Characteristic	Unit of measure	Symptomatic reherniation			Reoperation
		HR	95% CI	P-value	HR	95% CI	P-value
Univariate Cox model
ODI	Per 10-point increase	1.26	1.07, 1.47	0.004	1.09	0.90, 1.33	0.37
Sex	Female vs male	1.90	1.20, 2.99	0.006	2.68	1.53, 4.70	<0.001
PCS	Per 10-point decrease	1.49	1.04, 2.11	0.03	1.55	1.00, 2.40	0.049
Leg pain	Per 10-point increase	1.20	1.00, 1.41	0.05	1.26	1.01, 1.57	0.04
MCS	Per 10-point decrease	1.18	0.98, 1.41	0.08	1.16	0.94, 1.46	0.17
Current smoker	Yes vs no	1.37	0.87, 2.16	0.18	2.17	1.24, 3.80	0.007
Age ^a	Per 10-year decrease	1.05	0.84, 1.30	0.68	0.94	0.72, 1.22	0.66
Body mass index	Per 5-kg/m^2 increase	1.03	0.79, 1.36	0.83	0.94	0.67, 1.32	0.73
Level of herniation	Lumbar vs lumbosacral	1.04	0.65, 1.66	0.86	1.01	0.57, 1.77	0.98
Multivariate Cox model
Sex	Female vs male	1.72	1.08, 2.74	0.02	2.81	1.60, 4.94	<0.001
ODI	Per 10-point increase	1.22	1.04, 1.41	0.01	—	—	—
Current smoker	Yes vs no	—	—	—	2.30	1.31, 4.04	0.004

Notes: ^aAge was not associated with the risk of symptomatic reherniation or reoperation.

Abbreviations: CI, confidence interval; HR, hazard ratio; MCS, Mental Component Summary; ODI, Oswestry Disability Index; PCS, Physical Component Summary.

Table 3 Results of annular closure device postmarket registries by age group

Characteristic	≥60 years	<60 years
Symptomatic reherniation through 3 years	3.2% (SE 3.2%)	14.9% (SE 6.6%)
Reoperation through 3 years	0%	8.2% (SE 2.3%)
Leg pain MCID responder^a	80.0% (32/40)	69.9% (144/206)
ODI MCID responder^a	92.7% (38/41)	72.3% (149/206)

Notes: ^aPercentage of patients who achieved the MCID without a reoperation through 2 years minimum follow-up.

Abbreviations: MCID, minimal clinically important difference; ODI, Oswestry Disability Index; SE, standard error.

Table S1 List of participating centers and patient enrollment totals

Site name	Number of patients enrolled
LKH Graz (Graz, Austria)	25
ZNA Middleheim (Antwerp, Belgium)	48
OLVG-location West (formerly: Sint Lucas Andreas Ziekenhuis) (Amsterdam, The Netherlands)	49
St. Bonifatius Hospital GMbH (Lingen, Germany)	65
Klinikum Augsburg (Augsburg, Germany)	20
Charite-Virchow-Klinikum (Berlin, Germany)	17
University Medical Center Schleswig-Holstein (Kiel, Germany)	25
OLV Ziekenhuis (Aalst, Belgium)	60
Universitätsmedizin Mannheim (Mannheim, Germany)	25
University Hospital Dϋsseldorf (Dϋsseldorf, Germany)	25
Donauisar Klinikum Deggendorf (Deggendorf, Germany)	40
Asklepios Westklinikum Hamburg (Hamburg, Germany)	13
Isala Ziekenhuis (Zwolle, The Netherlands)	17
Medical University Innsbruck (Innsbruck, Austria)	25
A.Z Nikolaas Hospital (St. Nikolaas, Belgium)	5
Haaglansden Medical Center: Antoniushove (Den Haag, The Netherlands)	19
Haaglanden Medical Center: Westeinde (Den Haag, The Netherlands)	1
Kantonsspital Aarau (Aarau, Switzerland)	60
Knappschafts-Krankenhaus Bochum-Langendreer (Bochum, Germany)	8
Centre Hospitalier Régional Universitaire de Lille (CHRU), Hôpital Roger Salengro (Lille, France)	2
Orthopädische Klinik und Poliklinik, Universitätsmedizin Rostock (Rostock, Germany)	5