Analysis of 1027 Adverse Events Reports for Interspinous Process Devices From the US Food and Drug Administration Manufacturer and User Facility Device Experience Database

Gregory S. Kazarian; Yusef J. Jordan; Mitchell Johnson; Satyaj Bhargava; Robert Cecere; Takashi Hirase; Sheeraz Qureshi; James Dowdell; Evan Sheha; Francis Lovecchio; Sravisht Iyer

doi:10.14444/8652

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Figure 1
Summary of reports generated from the Manufacturer and User Facility Device Experience database for “Prosthesis, Spinous Process Spacer/Plate.”
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Figure 2
Number of adverse events of each type per year.

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Table 1

Intraoperative and postoperative adverse events related to interspinous process devices.

Complications	Across Implants^{^a}				Within Implants^{^b}
Complications	Coflex	Superion	X-Stop	Overall, % (n)	Coflex	Superion	X-Stop
Intraoperative	2.0%	97.0%	1.0%	42.8% (404)	21.1%	47.3%	5.2%
Implant malfunction	2.1%	97.6%	0.3%	39.7% (374)	21.1%	44.1%	1.3%
Fracture	0.0%	85.7%	14.3%	2.2% (21)	0.0%	2.2%	3.9%
Dural tear	0.0%	100.0%	0.0%	0.6% (6)	0.0%	0.7%	0.0%
Hemorrhage	0.0%	100.0%	0.0%	0.2% (2)	0.0%	0.2%	0.0%
Implant migration	0.0%	100.0%	0.0%	0.1% (1)	0.0%	0.1%	0.0%
Postoperative	5.6%	80.9%	13.5%	57.2% (539)	78.9%	52.7%	94.8%
Inadequate efficacy	4.4%	78.9%	16.7%	26.6% (251)	28.9%	23.9%	54.5%
Implant migration	2.8%	89.4%	7.8%	19.1% (180)	13.2%	19.4%	18.2%
Fracture	7.8%	78.1%	14.1%	6.8% (64)	13.2%	6.0%	11.7%
Infection or wound healing	26.7%	60.0%	13.3%	3.2% (30)	21.1%	2.2%	5.2%
Neurological complication	7.7%	61.5%	30.8%	1.4% (13)	2.6%	1.0%	5.2%
Epidural hematoma	0.0%	100.0%	0.0%	0.1% (1)	0.0%	0.1%	0.0%

↵a Across group analysis demonstrates that the proportion of total adverse events for a given adverse event type is attributed to each implant manufacturer.
↵b Within groups analysis demonstrates the contribution of each adverse event to the total adverse events pool for a given manufacturer/implant.

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Table 2

Malfunctions of interspinous process devices.

Implant Malfunctions	Across Implants^{^a}				Within Implants^{^b}
Implant Malfunctions	Coflex	Superion	X-Stop	Overall, % (n)	Coflex	Superion	X-Stop
Spindle cap malfunction during deployment	0.0%	100.0%	0.0%	52.1% (195)	0.0%	53.4%	0.0%
Broke on deployment or broke off of inserter/connector	0.0%	100.0%	0.0%	35.8% (134)	0.0%	36.7%	0.0%
Fragmentation/bending	24.2%	75.8%	0.0%	8.8% (33)	100.0%	6.8%	0.0%
Not specified	0.0%	91.7%	8.3%	3.2% (12)	0.0%	3.0%	100.0%

↵a Across group analysis demonstrates that the proportion of total implant malfunctions for a given malfunction type is attributed to each implant manufacturer.
↵b Within groups analysis demonstrates the contribution of malfunction type to the total pool of implant malfunctions for a given manufacturer/implant.

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Table 3

Resultant outcome as a function of adverse event type related to interspinous process devices.

Complications	Across Implants^{^a}				Within Implants^{^b}			Within Implants, as Percentage of Each Complication^{^c}
Complications	Coflex	Superion	X-Stop	Overall	Coflex	Superion	X-Stop	Coflex	Superion	X-Stop	Overall
Implant malfunction	2.1%	97.6%	0.3%	39.7%	21.1%	44.1%	1.3%	-	-	-	-
No clinical signs, symptoms, or conditions	0.0%	100.0%	0.0%	33.8%	0.0%	38.5%	0.0%	0.0%	87.4%	0.0%	85.3%
Persistent pain	2.9%	97.1%	0.0%	3.6%	2.6%	4.0%	0.0%	12.5%	9.0%	0.0%	9.1%
Revision	38.9%	55.6%	5.6%	1.9%	18.4%	1.2%	1.3%	87.5%	2.7%	100.0%	4.8%
Procedure aborted	0.0%	100.0%	0.0%	0.3%	0.0%	0.4%	0.0%	0.0%	0.8%	0.0%	0.8%
Inadequate efficacy	4.4%	78.9%	16.7%	26.6%	28.9%	23.9%	54.5%	-	-	-	-
Revision	4.2%	87.4%	8.4%	22.8%	23.7%	22.7%	23.4%	81.8%	94.9%	42.9%	85.7%
Persistent pain	5.6%	27.8%	66.7%	3.8%	5.3%	1.2%	31.2%	18.2%	5.1%	57.1%	14.3%
Implant migration	2.8%	89.5%	7.7%	19.2%	13.2%	19.6%	18.2%	-	-	-	-
Revision	2.0%	91.5%	6.5%	16.2%	7.9%	16.9%	13.0%	60.0%	86.4%	71.4%	84.5%
Persistent pain	7.7%	84.6%	7.7%	2.8%	5.3%	2.7%	2.6%	40.0%	13.6%	14.3%	14.4%
No clinical signs, symptoms, or conditions	0.0%	0.0%	100.0%	0.2%	0.0%	0.0%	2.6%	0.0%	0.0%	14.3%	1.1%
Fracture	5.9%	80.0%	14.1%	9.0%	13.2%	8.2%	15.6%	-	-	-	-
Revision	10.0%	67.5%	22.5%	4.2%	10.5%	3.3%	11.7%	80.0%	39.7%	75.0%	47.1%
Persistent pain	3.8%	96.2%	0.0%	2.8%	2.6%	3.0%	0.0%	20.0%	36.8%	0.0%	30.6%
Procedure aborted	0.0%	91.7%	8.3%	1.3%	0.0%	1.3%	1.3%	0.0%	16.2%	8.3%	14.1%
No clinical signs, symptoms, or conditions	0.0%	71.4%	28.6%	0.7%	0.0%	0.6%	2.6%	0.0%	7.4%	16.7%	8.2%
Infection or wound healing	26.7%	60.0%	13.3%	3.2%	21.1%	2.2%	5.2%	-	-	-	-
Revision	30.4%	52.2%	17.4%	2.4%	18.4%	1.4%	5.2%	87.5%	66.7%	100.0%	76.7%
Antibiotics	14.3%	85.7%	0.0%	0.7%	2.6%	0.7%	0.0%	12.5%	33.3%	0.0%	23.3%
Neurological complication	7.7%	61.5%	30.8%	1.4%	2.6%	1.0%	5.2%	-	-	-	-
Revision	10.0%	50.0%	40.0%	1.1%	2.6%	0.6%	5.2%	100.0%	62.5%	100.0%	76.9%
Neurological issue	0.0%	100.0%	0.0%	0.3%	0.0%	0.4%	0.0%	0.0%	37.5%	0.0%	23.1%
Dural tear	0.0%	100.0%	0.0%	0.6%	0.0%	0.7%	0.0%	-	-	-	-
Dura blood patch	0.0%	100.0%	0.0%	0.3%	0.0%	0.4%	0.0%	-	50.0%	-	50.0%
Procedure aborted	0.0%	100.0%	0.0%	0.2%	0.0%	0.2%	0.0%	-	33.3%	-	33.3%
Persistent pain	0.0%	100.0%	0.0%	0.1%	0.0%	0.1%	0.0%	-	16.7%	-	16.7%
Hemorrhage	0.0%	100.0%	0.0%	0.2%	0.0%	0.2%	0.0%	-	-	-	-
Procedure aborted	0.0%	100.0%	0.0%	0.2%	0.0%	0.2%	0.0%	-	100.0%	-	100.0%
Epidural hematoma	0.0%	100.0%	0.0%	0.1%	0.0%	0.1%	0.0%	-	-	-	-
Revision	0.0%	100.0%	0.0%	0.1%	0.0%	0.1%	0.0%	-	100.0%	-	100.0%

↵a Across group analysis demonstrates that the proportion of total adverse events for a given adverse event type is attributed to each implant manufacturer.
↵b Within groups analysis demonstrates the contribution of each adverse event to the total adverse events pool for a given manufacturer/implant.
↵c Within groups analysis as a percentage of each complication indicates the percentage of each outcome for each implant within a specific adverse event type.

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Table 4

Reasons for revision after placement of interspinous process devices.

Revision (n = 460)	Across Implants^{^a}				Within Implants^{^b}
Revision (n = 460)	Coflex	Superion	X-Stop	Overall, % (n)	Coflex	Superion	X-Stop
Inadequate efficacy	4.2%	87.4%	8.4%	46.7% (215)	29.0%	49.1%	39.1%
Implant migration	2.0%	91.5%	6.5%	33.3% (153)	9.7%	36.6%	21.7%
Fracture	10.0%	67.5%	22.5%	8.7% (40)	12.9%	7.0%	19.6%
Infection or wound healing	30.4%	52.2%	17.4%	5.0% (23)	22.6%	3.1%	8.7%
Implant malfunction	38.9%	55.6%	5.6%	3.9% (18)	22.6%	2.6%	2.2%
Neurological complication	10.0%	50.0%	40.0%	2.2% (10)	3.2%	1.3%	8.7%
Epidural hematoma	0.0%	100.0%	0.0%	0.2% (1)	0.0%	0.3%	0.0%
IPD-specific complication	6.6%	83.9%	9.5%	45.9% (211)	45.2%	46.2%	43.5%

Abbreviation: IPD, interspinous process device.
↵a The percentage of revisions attributed to each implant brand is shown for each revision indication.
↵b The percentage of overall revisions indicates the percentage of overall revisions attributed to each adverse event type. IPD-specific complications include implant migration, fracture, and implant malfunction.

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Table 5

Type of revision after interspinous process device placement.

Type of Revision	Across Implants				Within Implants
Type of Revision	Coflex	Superion	X-Stop	Overall, % (n)	Coflex	Superion	X-Stop
Explant	5.3%	88.5%	6.2%	59.9% (226)	40.0%	67.1%	28.6%
Revision interspinous implant	7.1%	88.1%	4.8%	22.3% (84	20.0%	24.8%	8.2%
Explant, decompression ± fusion	16.7%	31.5%	51.9%	14.3% (54	0.0%	0.3%	0.0%
Irrigation and debridement	33.3%	66.7%	0.0%	1.6% (6)	6.7%	1.3%	0.0%
Unknown	20.0%	20.0%	60.0%	1.3% (5)	3.3%	0.3%	6.1%
Implanted level above	0.0%	100.0%	0.0%	0.3% (1)	0.0%	0.3%	0.0%
Microdiscectomy	0.0%	100.0%	0.0%	0.3% (1)	30.0%	5.7%	57.1%