Intrathecal Drug Delivery Systems
Study Participants
Centers
The following tables and graphs were generated based on data collected between the date of initiation of the Implantable Systems Performance Registry (ISPR) for intrathecal drug delivery systems on August 7, 2003 and the report cut-off date of October 24, 2008. Fifty centers enrolled and contributed patients to the intrathecal drug delivery systems section of the report.
Subjects
As the table below demonstrates, there were 3,786 total intrathecal drug delivery system patients enrolled in the ISPR through October 24, 2008. The table lists 3 primary indications with corresponding sub-indications as reported by the physician at implant. Fifty-three percent of patients were implanted with an intrathecal drug delivery system for treatment of non-malignant pain, followed by 29.3% for treatment of intractable spasticity, and 17.7% for treatment of malignant pain.
Primary Intrathecal Drug Delivery System Treatment Indications Primary Intrathecal Drug Delivery System Treatment Indications
*Refer to product labeling for approved indications. Primary treatment indication information is obtained through the Medtronic Device Registration System.
†RSD is reflex sympathetic dystrophy. CRPS is complex regional pain syndrome. |
Pumps
From August 2003 to the report cut-off date of October 24, 2008, 4,214 pumps were followed in the Implantable Systems Performance Registry (ISPR). Differences between the total number of patients (n=3,786) versus pumps were due to the fact that some patients were subsequently re-implanted with a pump 1, 2, or more times.
Most of the pumps enrolled were either SynchroMed EL (30.7%) or SynchroMed II (69.2%), and a small number of pumps were SynchroMed Classic (0.2%). The majority of SynchroMed II pumps were new pumps (2,463/2,914, 84.5%), whereas the majority of SynchroMed EL pumps were existing pumps (1,112/1,293, 86.0%). Total prospective follow-up time for pumps was 93,304 pump months.
|
There were 38 pumps that experienced an event requiring surgical intervention with an underlying reported pump etiology related to pump function. For pumps enrolled in the ISPR, the current return rate to Medtronic Returned Product Analysis (RPA) was 257/1,214 (21%). The proportion was based upon the number of pumps received by RPA, divided by the total number of explanted devices plus the total number of pumps in patients who have expired. Twenty-seven of the 38 pump events were analyzed by Medtronic RPA: 24 pumps failed related to motor stalls and 3 pumps had cracked pump tubes. The remaining 11 pump events were based upon physician report only (pumps were not returned to Medtronic) and included: 8 events related to pump underinfusion, 2 events related to no pump infusion, and 1 event related to the inability to interrogate the pump. There were an additional 1,646 pumps censored in the analysis as a result of patient expired, pump explanted, patient lost to follow-up, other surgical intervention, or therapy abandonment attributed to an event unrelated to the pump. Of the 121 explanted due to normal battery depletion that were subsequently returned to RPA, 5 were recoded as product performance events based on RPA findings. No deaths were reported among patients followed in the ISPR as a result of a product performance related event or the delivery of infusion therapy. |
Pump Survival Curves Pump Survival Curves The 2009 Product Performance report included two device models: SynchroMed EL and SynchroMed II. Click the buttons to view the pump event curves for each model. |
Pump Survival Summary Pump Survival Summary The figures and tables in this section represent pump survival and 95% confidence intervals where at least 20 pumps contributed to each interval. At 4 years of follow-up, the 95% confidence intervals for the SynchroMed EL and SynchroMed II 40 ml pumps do not overlap, indicating that survival from pump related events is significantly different between these pump models. Medtronic chose to voluntarily discontinue the SynchroMed EL pump in August 2007 in the United States based on broad customer acceptance of the SynchroMed II pump for all approved indications, the high reliability record of the SynchroMed II pump, and the fact that the SynchroMed II pump offers additional performance features beyond those available in the SynchroMed EL pump. |
SynchroMed EL Survival Curve Catheters
From August 2003 to the report cut-off date of October 24, 2008, 3,991 catheters were followed in the Implantable Systems Performance Registry (ISPR). The total number of catheters was not equal to the total number of pumps (n=4,214) because a patient may have undergone a pump replacement but used the same catheter, or patients may have been implanted with Medtronic pumps and non-Medtronic catheters which were not registered with Medtronic Device Registration System (DRS). Furthermore, the ISPR did not collect information for non-registered catheters for existing patients. Total prospective follow-up time for catheters was 93,374 catheter months.
A total of 37.5% of the catheters were Model 8709AA catheters, 16.4% were Model 8709 catheters, 13.0% were Model 8731 catheters, 12.0% were Model 8711 catheters, 5.4% were Model 8709SC catheters, 4.4% were Model 8703W catheters, 1.0% were Model 8731SC catheters, and 0.9% were other or unspecified catheters. An additional 2.7% were considered catheters revised as designed, (8731 catheters that had been repaired with an 8596 proximal or 8598 distal revision kit); 3.8% were considered catheters revised not as designed (Medtronic non-8731 catheters that had been repaired with an 8596 proximal or 8598 distal revision kit catheters); and 2.9% were catheters grafted not as designed (catheters that involve the ad-hoc assembly of components other than a Medtronic repair kit or brand new catheter).
Catheter Events Catheter Events There were 236 catheters with events that required surgical intervention with an underlying reported etiology related to the catheter. Of these events, 89 were related to a kink or occlusion, 56 were related to dislodgement, 45 were related to a break or cut in the catheter, 20 were related to catheter disconnection, 10 were related to pump connector break/cut, 7 were related to catheter puncture, 5 were related to loss of therapeutic effect, 3 were related to sheared catheter tip, and 1 was unknown. An additional 1,300 catheters were censored in the analysis due to patient expired, patient lost to follow-up (eg, patient moved, transferred care to another provider, study withdrawal), catheter explanted, other surgical intervention, or therapy abandonment attributed to an event unrelated to the catheter. |
Catheter Survival Curves Catheter Survival Curves The 2009 Product Performance report included several catheter models. Click below to view the catheter event curves for each model. |
Catheter Survival Summary Catheter Survival Summary The figures and tables in this section represent catheter survival and 95% confidence intervals where at least 20 catheters contributed to each interval. At 2 and 3 years of follow-up, the 95% confidence intervals for models 8709, 8709AA, 8711, 8731, revised as designed, revised not as designed, and grafted not as designed catheters overlap, indicating that survival from catheter related events is not statistically significantly different between these catheter models. The sample size for Models 8709SC and 8731SC catheters is not sufficient to report survival at 2 or 3 years of follow-up. Similarly, these data indicate at 4 years of follow-up, the 95% confidence intervals for Models 8709, 8709AA, 8711, 8731, and revised by design catheters overlap, indicating that survival from catheter related events are not statistically significantly different between these 4 catheter models. The sample size for Models 8709SC and 8731SC, revised not as designed, and grafted not as designed catheters is not sufficient to report survival at 4 years of follow-up. Although not statistically significantly different, the survival estimates indicate that the survival of catheters revised not as designed (Medtronic non-8731 catheters that had been repaired with an 8596 proximal or 8598 distal revision kit catheters) and catheters grafted not as designed (those catheters repaired or spliced using non-Medtronic components, or Medtronic components other than the Model 8596 or 8598 revision kits) have a lower probability of survival at 1 and 2 years of follow-up than any other catheter model, including catheters revised as designed. Explanations for this finding remain speculative, and include small sample size and a relatively brief observation period compared to other catheter models. Other non-statistical explanations may include device-related causes and/or system troubleshooting errors. Medtronic catheter repair kits and 2-piece catheters include specially designed connector pins and strain relief sleeves to splice the catheter segments together. Catheters grafted not as designed, by definition, involve the ad-hoc assembly of components other than a Medtronic repair kit or brand new catheter. Another possible explanation is that a drug-delivery system or intrathecal drug and cerebrospinal fluid mixing or flow anomaly existed that was not corrected by assembly of a grafted not as designed catheter system. Medtronic will continue to monitor and review the performance and survival of catheters revised not as designed and catheters grafted not as designed. Medtronic recommends following the labeling for the Model 8596 and 8598 revision kits. |
Events Summary
Product Performance Related Events Product Performance Related Events There were 1,982 events reported between August 2003 and October 24, 2008 in patients with intrathecal drug delivery systems. Fourteen percent of these events (274/1,982) were related to the pump or catheter, categorized as product performance related events and are presented graphically within this report.
*Patient experienced a worsening of symptoms, which physician attributed to underinfusion for various reasons
†Physician reported worsening of symptoms and loss of therapeutic effect, due to an unspecified catheter related etiology. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Non-Product Performance-Related Events Non-Product Performance-Related Events Fifty-one percent of the events (1,013/1,982) were due to the patient expiring or becoming lost to follow-up (eg, patient moved, transferred care to another provider, study withdrawal). No deaths were reported as a result of a device related event or the delivery of infusion therapy. Twenty percent of the total events (401/1,982) were related to the surgery or procedure (n=173), or attributed to the patient or delivery of the therapy (n=228). Fifteen percent of the events (294/1,982) were related to normal battery depletion.
* Trial catheter revision mean calculation excludes an extreme observation (ie, 131 months to event)
† Elective action includes therapy abandoned or device explants primarily due to patient requests for device removal or changes in pump reservoir size with no device/therapy related etiology. ‡ Refers to intraspinal drug overdoses or underdoses that required a hospital stay, but not a device surgical intervention. § Pump was removed due to corrective surgery (eg, patient had lumbar fusion surgery and symptoms resolved). || Pump replaced to increase reservoir volume due to frequent refill intervals ¶ Includes definite or probable inflammatory mass. Definite classification required surgical and histological verification or clinical symptoms plus contrast enhanced MRI or CT myelogram and resolution of lesion following cessation of drug exposure. Probable classification required no surgical or histological verification, but clinical criteria and enhanced MRI or CT myelogram criteria were present. ** Medical records reported inflammatory mass, but there was no surgical or histological verification, no clinical criteria, and no radiographic data available. †† For products that are returned, and RPA establishes a root cause or finds no anomaly, results reported herein default to the RPA finding. ‡‡ Physician assigned the event etiology as patient effects. No additional information was available. §§ Physician reported that patients were non-compliant with pump refill schedule and/or routine medical care. || || Device was no longer needed because patients’ symptoms were attenuated through other medical therapies or resolution of the underlying disease. ¶¶ Physician reported event as therapy/patient effect and did not specify location of wound dehiscence. *** Event summary frequencies are at the patient level, not device level. ††† Seventy-one percent of patient deaths occurred in patients with a primary indication of malignant pain. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
2009 Medtronic Product Performance Report: Data through October 24, 2008.