Table 2

Publication Table.

Author, YearStudy DesignCountry of OriginOxford Level of Evidence (LOE)NImplantTechniqueDemographicsResultsComplications
Musacchio, 20165- year follow up Prospective, multi-center IDE RCTUSI344coflexDirect decompression via laminectomy w/ subsequent implantation coflex ILS OR Decompression via laminectomy w/ subsequent posterolateral instrumented fusionAge coflex: 62.1 (41-81) years Age fusion: 64.1 (41-82) years Sex coflex: 106F/109M Sex fusion: 58F/49M Moderate-to-severe lumbar stenosis w/ back pain ODI ≥ 20/ 50 (40%) VAS ≥ 50/1005 years, 50.3% of D+ILS vs. 44% of D+PS patients (p>0.35) met the composite success criteria. Reoperation/ revision rates were similar in the two groups (16.3% vs. 17.8%; p >0.90)There were 3/215 major device related complications in the D+ILS group and 5/107 in the fusion group at Month 60 (1.4% vs. 4.7%; p>0.10); 60 months: no significant difference in the cumulative total occurrences of reoperations/revisions between the D+ILS group 35/ 215 (16.3%) and D+PS group 19/107 (17.8%) (p>0.90); wound-related reoperations: 7 D+ILS patients (3.3%) and 1 D+PS patient (0.09%); under-treated: 5 D+ILS patients (2.3%) and 2 D+PS patients (1.9%) who underwent early revisions; device-related reoperations: D+ILS group: pars fracture, D+PS group: broken instrumentation; devicerelated reoperations: 6 patients in the D+ILS (2.8%) and 7 patients in the D+PS group (6.5%)
Forsth, 2016RCTSwedenI247N/ADecompression with or without fusionAge NO DS w/fusion: 66 (57-75) years; Age NO DS w/out fusion: 66 (58-74); Age +DS w/ fusion: 68 (61-75); Age +DS w/out fusion: 67 (60-74) yearsNo significant difference between the groups in the mean score on the ODI at 2 years (27 in the fusion group and 24 in the decompression-alone group, P=0.24) or in the results of the 6-minute walk test (397 m in the fusion group and 405 m in the decompression-alone group, P=0.72)Dural tears occurred in 12 patients (11%) in the fusion group and in 13 patients (11%) in the decompression-alone group ; Postoperative wound infection that required treatment with antibiotic agents but not reoperation with wound débridement occurred in 11 patients (10%) in the fusion group and in 5 patients (4%) in the decompression-alone group. Myocardial infarction, stroke, or thromboembolic events occurred in 3 patients (3%) in the fusion group and in 5 patients (4%) in the decompression-alone group; additional lumbar-spine surgery before the end of October 2015: 22% in the fusion group and 21% in the decompression-alone group
Bae, 20163-year Follow-up Prospective, multicenter IDE RCTUSI344coflexDirect decompression via laminectomy w/ subsequent implantation coflex ILS OR Decompression via laminectomy w/ subsequent posterolateral instrumented fusionAge coflex: 62.1 (41-81) years Age fusion: 64.1 (41-82) years Sex coflex: 106F/109M Sex fusion: 58F/49M Moderate-to-severe lumbar stenosis w/ back pain ODI ≥ 20/ 50 (40%) VAS ≥ 50/100Composite clinical success at 36 months was achieved by 62.2% among 196 coflex Interlaminar Stabilization patients and 48.9% among 94 fusion patients (difference = 13.3%, 95% confidence interval, 1.1%-25.5%, P = .03)Important harms/severe adverse events that were deemed either definitely or probably related to the device occurred in 19 ILS patients (8.8%) and in 16 fusion patients (15%) (Fisher exact test, P = .13). Important harms that were deemed either definitely or probably related to the surgery occurred in 26 ILS patients (12.1%) and 19 fusion patients (17.8%) (P = .18); New or worsening pain at operating site 40% both groups; nonoperative site events were musculoskeletal and neurological events experienced in 64.2% vs 66.4% and 26.0% and 24.3% in ILS and fusion patients; 2 case examples of spinous process fracture after implantation; reoperation for ILS: 16 patients with persistent pain with 7 undergoing reoperation at the index level alone, 8 undergoing reoperation at the index level plus 1 or more adjacent levels, and 1 undergoing reoperation at an adjacent level only; 7 patients with wound issues including 4 wound infections, 2 cerebrospinal fluid leaks, and 1 wound dehiscence; 3 patients with component loosening, and 4 patients with fractures including 2 spinous process fractures and 2 pars fractures; reoperation for fusion: 9 patients with persistent pain with 2 patients undergoing reoperation at the index level alone, 6 patients undergoing reoperation at the index level plus 1 or more adjacent levels, and 1 patient undergoing reoperation at an adjacent level alone; 2 patients underwent reoperation for component failure, including 1 with a broken screw and 1 with screw loosening; 1 patient underwent reoperation for a pars fracture at an adjacent level; and 1 underwent reoperation for a wound hematoma
Sigmundsson, 2016Prospective register studySwedenII5100N/Adecompression only OR decompression with fusionAge: 73 years (SD 9.8); 49.9% male 50.1 % female 88% decompression only, 12% decompression with fusion; Cohort: operated on for CSS from January 2003 to June 20104167 satisfied patients and 933 dissatisfied patients; Factors decreasing the likelihood for satisfaction included previous spine surgery OR: 0.4 (95 % CI: 0.3-0.5), smoking OR: 0.6 (95 % CI: 0.4-0.8), unemployment OR: 0.6 (95 % CI: 0.4-0.9), back pain exceeding 1 year OR: 0.6 (95 % CI: 0.4-0.9), back pain predominance OR: 0.7 (95 % CI: 0.5-0.8). Fusion surgery did not predict satisfaction OR: 1.3 (95 % CI: 0.9-1.9). Preoperative self-estimated walking distance >1000 m predicted satisfaction, OR: 2.4 (95 %: 1.6-3.6).No complications
Ghogawala, 2016Prospective RCTUSI66N/ADecompressive laminectomy with or without Instrumented (rigid pedicle screws affixed to titanium alloy rods) lumbar spinal fusionAge: 67 (50-80) years Grade I lumbar spondylolisthesis (degree of spondylolisthesis, 3 to 14 mm) with lumbar stenosis and neurogenic claudication with or without lumbar radiculopathyFusion group had a greater increase in SF-36 physical-component summary scores at 2 years after surgery than did the decompression-alone group (15.2 vs. 9.5, for a difference of 5.7; 95% confidence interval, 0.1 to 11.3; P=0.046); fusion group remained greater at 3 and 4 years More blood loss and longer hospital stays occurred in the fusion group than in the decompression-alone group (P<0.001 for both comparisons). The cumulative rate of reoperation was 14% in the fusion group and 34% in the decompression-alone group (P=0.05).Fusion group had a lower rate of reoperation over the course of 4 years than did the decompression-alone group (14% vs. 34%, P=0.05); reoperations performed in the decompression-alone group were at the index level to address subsequent clinical instability. In contrast, all the reoperations performed in the fusion group were at an adjacent lumbar level (either disk herniation or clinical instability); surgical complications, blood loss, length of stay, and length of procedure were significantly greater in the fusion group than in the decompression-alone group
Chen, 2016Retrospective cohort studyChinaIII154coflexTopping-off surgery (coflex with fusion) (76 patients) OR two-segment fusion surgery (88 patients)Age: 40–80 years; moderate to severe lumbar spine stenosis; unsuccessful conservative treatment for more than six months; ODI score ≥40 (out of 100); VAS for back pain score ≥50 (out of 100)Significant differences in clinical outcomes were observed between these two groups at three postoperative years (all, p < 0.05). Compared with the fusion group, the topping-off group showed preserved mobility at the coflex™ level (p = 0.000), which is associated with less blood loss (p = 0.000), shorter duration of surgery (p = 0.000) and lower incidence of ASD (Chi-square test, rate topping-off vs fusion = 13.2 vs 26.1 %, p = 0.039)No patients in either of the groups had severe intra-operative or post-operative complications, such as nerve root injury, dural tears, cauda equina injury, vertebral fracture, internal fixation system fracture, loosened screw, malpositioned screw, dislodgement of the interbody device, fixed wing breakage or spinal process fracture
Lee, 2016Retrospective cohort studyKoreaIII30coflex**studied erosion vs. non-erosion after coflex implantAge: 62.2 (40-82); M/F ratio: 15:15Erosion group showed substantially higher values in preoperative ADH, postoperative posterior disc height (PDH), and intervertebral foramen height (6.52 mm vs. 8.05 mm; 5.80 mm vs. 8.03 mm; 19.20 mm vs. 21.06 mm). Postoperative ROM and ROM ratio were higher in the erosion group (5.95° vs. 8.47° and 0.659 vs. 0.938).14 patients (47%) showed erosion at the spinous process–coflex interface after surgery
Bae, 2015Retrospective analysis of RCTUSI344coflexDecompression w/ interlaminar stabilization OR decompression with fusion230 and 114 patients receiving ILS and fusion respectively during the enrollment period from 2006 through 2010 at 21 participating US sites; moderate to severe stenosis, age range from 40-80; ODI score ≥ 40 (out of 100), VAS for back pain of ≥ 50mm (out of 100mm), failing ≥ 6 months of conservative care including ≥ 1 epidural steroid injection, no prior decompression surgery, up to a Grade 1 stable spondylolisthesis48 month cumulative rates of index level second surgeries were 16.1% (SE = 2.6%; 35/215) and 14.9% (3.6%; 15/107) for ILS and fusion, respectively; patients with no index level re-operations or lumbar steroid injections, 86.2% (106/123) of ILS and 72.4% (42/58) of fusion subjects had a clinically significant improvement in ODI scores (p = 0.038)Through 48 months, adverse events rates were similar in both cohorts, although the incidence of events that were deemed 'definitely or probably related to the implant' occurred in 14.9% (32/215) ILS patients and in 20.6% (22/107) of fusion patients (p = 0.21). Events that were classified as 'severe' occurred in 8.8% of the ILS population and 15.0% of the fusion population (p = 0.13)
Sigmundsson, 2015Retrospective register studySwedenIII839N/A**Compared PLP and PBP in patients who got either decompression alone or decompression with fusionAge D PLP: 73.8 (SD 9.3); Age DF PLP: 68.8 (SD 8.7); Age D PBP: 73.2 (SD 10.6); Age DF PBP: 69.1 (SD 9.1); Gender: PLP M: D: 38, DF: 59; F: D: 87; DF: 200; PBP M: D: 31; DF: 62; F: D 89; DF: 270; older than 50 years operated for DS at the L4–L5 level with either decompression only (D) or decompression and instrumented posterolateral fusion (DF)Patients with PLP reported a 7.9-mm more improvement on the VAS for BP with fusion, compared with D (95% confidence interval [CI], 0.7–15.2), p=.03; patients with PBP benefited from adding fusion in terms of BP 7.1 (95% CI, 0.3–13.9, p=.04), LP 8.8 (2–15.7, p=.01), the ODI 5.7 (1.6–9.9, p=.006), and the EQ-5D 0.09 (1.7–0.02, p=.02) at the 1-year follow-up as the DF group reported greater change in the outcome compared with the D groupNo complications
Kumar, 2014 Prospective Prospective cohort study Singapore SingaporeII46coflexSpinal decompression with coflex implantation vs. decompression aloneSymptomatic LSS; The mean age of the patients in the coflex and the comparison group was 57.9 years (range, 40-74 years) and 61.8 years (range, 49-78 years; p=0.127), respectively. The male:female ratio in the respective groups was 13:9 (n=22, coflex group) and 14:10 (n=24, comparison group, p=0.958).Mean ODI score in the coflex group improved from 51.73 preoperatively to 22.91, 22.64 and 17.36 at six months, one year, and two years; mean ODI score in the comparison group improved from 49.58 preoperatively to 32.17, 30.08, and 28.50 at six months, one year, and two years; mean difference in ODI improvement between the two groups was 10.4 (95% confidence interval [CI], 8.8-12.1), being greater in the coflex groupOne patient in the coflex group (dural puncture) and four patients in the comparison group (3-dural puncture and 1-deep infection) had procedure related complications. The incidence of complications in the two groups was not significantly different (p=0.35)
Patil, 2014Retrospective comparative studyUSIII498N/ACompare reoperations, complications, and costs between LSS patients undergoing ID placement versus laminectomyLumbar spinal stenosis; MarketScan database (2007-2009); age: 73 yearsLonger length of stay was observed in the laminectomy cohort (2.5 days vs. 1.6 days, p<.0001), whereas ID patients accrued higher costs at index hospitalization ($17,674 vs. $12,670, p=.0001). Index hospitalization (7.5% vs. 3.5%, p=.099) and 90-day (9.2% vs. 3.5%, p=.028) complications were higher in the laminectomy cohort compared with the ID cohort. The ID patients had significantly higher reoperation rates than laminectomy patients at 12 months follow-up (12.6% vs. 5.8%, p=.026) and incurred higher cumulative costs than laminectomy patients at 12 months follow-up ($39,173 vs. $34,324, p=.289)Overall reoperation rate was 22.1% for all patients that had an initial ID placed ; most common type of reoperation was laminectomy (12.1%), followed by new ID placement (10.4%), revision interbody fusion (6.0%), and new interbody fusion (3.6%). Complications occurred in 16 (3.2%) patients at index hospitalization, 51 (10.2%) patients within 30 days, and in 51 (11.2%) patients within 90 days; total of 348 patients with at least 18 months follow-up, half of which underwent direct decompression via laminectomy and the other half indirect decompression by ID; patients who underwent laminectomy spent significantly more days at index hospitalization than patients who underwent ID placement (2.49 vs. 1.58, p<.0001)
Schmier, 2014Retrospective comparative cohortUSIII344coflexcoflex Interlaminar Stabilization Device vs. instrumented posterolateral fusionClinical data input was obtained from results reported in Davis et al. that describe a randomized Investigational Device Exemption (IDE) clinical trial comparing coflex to instrumented fusionFive-year costs were lower for patients implanted with coflex compared to those undergoing fusion. Average Medicare payments over 5 years were estimated at $15,182 for coflex compared to $26,863 for the fusion control, a difference of $11,681. Mean quality-adjusted life years were higher for coflex patients compared to controls (3.02 vs 2.97). Results indicate that patients implanted with the coflex device derive more utility, on average, than those treated with fusion, but at substantially lower costsNo complications
Davis, 2013 Prospective, Prospective, multicenter IDE RTUSI150coflexcoflex Interlaminar Stabilization OR laminectomy and PSFOnly the subset of patients from this overall cohort with Grade 1 spondylolisthesis (99 in the coflex group and 51 in the fusion group); mean ages of the coflex and fusion cohorts were 63.1 ± 7.9 years and 65.0 ± 8.5 years; coflex cohort, there were 58 women and 41 men compared with 32 women and 19 men in the fusion cohortODI: baseline: coflex cohort had an average score of 21.1 compared with 22.7 for fusions (p = 0.66) ; percentage of patients that achieved a 15-point reduction in ODI at 2 years from baseline was 86.1% for coflex and 81.0% for fusion (p = 0.60); ZCQ: coflex cohort performed significantly better than fusion controls with respect to ZCQ patient satisfaction at 24 months (p = 0.05); SF-12: no significant differences at any pre- or postoperative time point; VAS: coflex subjects experienced a 55-point improvement in the back VAS score compared with 58 points for fusions (p > 0.05) at 24 monthsOverall rate of operative site AEs between the groups was similar for coflex (43.4%) and fusions (37.3%, p = 0.49). The rate of severe adverse events that were definitely or probably related to the implant was 9.1% in the coflex group and 7.8% in the fusion group (p = 1.0). Wound-related problems were seen in 14.1% of coflex patients compared with 13.7% in the fusion controls (p = 1.0). The rate of spinous process fracture in the coflex cohort was 18% (18 of 99); however, by 24 months 7 of these 18 fractures had healed; CCS for patients experiencing a spinous process fracture was 61.1% (11 of 18), compared with 63.2% (48 of 76, p = 1.00) in the cohort without a fracture; 6.4% of coflex subjects experienced device movement greater than 5 mm at 24 months. Wound-related problems included wound drainage, superficial infection, dehiscence, seroma, and delayed healing of incision. Only 1 patient had an irrigation and debridement procedure due to wound dehiscence. Within the fusion control group, a total of 29% (15 of 51) developed a pseudarthrosis; overall reoperation rate was 14.1% (14 of 99) and 5.9% (3 of 51) for the coflex and fusion controls, respectively (p = 0.18)
Davis, 2013Prospective, multicenter IDE RTUSI322coflexcoflex Interlaminar Stabilization OR laminectomy and PSFThree hundred twenty-two patients (215 coflex and 107 fusions) from 21 sites in the United States were enrolled between 2006 and 2010.; average age (standard deviation, range) for the coflex cohort was 62.1 (9.2, 41–81) years, while the average age for the fusion control cohort was 64.1 (9.0, 41–82) yearsAt 24 months ODI: coflex: 22.0; fusion: 26.7, P = 0.075; greater proportion of patients taking coflex achieving a 15-point reduction in ODI at 24 months (coflex: 85.8%; fusion: 76.7%, P = 0.08; 24 months, SF-12 scores had improved significantly more from baseline in the coflex cohort (15.5 points) compared with fusion controls (12.6, P = 0.050), Significant improvements in the coflex cohort compared with fusion controls were also seen at 6 weeks (P = 0.048), 3 months (P = 0.032); early postoperative period: coflex cohort had a trend toward significantly lower VAS back pain scores at 3 months (P = 0.062) and 6 months (P = 0.063). VAS leg pain score was significantly better in the coflex cohort at 3 months (P = 0.019) and a trend at 6 months (P = 0.058); index level range of motion was maintained with coflex, while fusion subjects exhibited an expected significant decrease in the index level range of motion.fusion group demonstrated significantly greater superior adjacent level range of motion when compared with coflex (P = 0.002); 24 months, 135 of 204 coflex subjects (66.2%) and 60 of 104 (57.7%) fusion controls met the criteria for overall study success, demonstrating noninferiority (posterior probability = 0.999).Operative site adverse event: 49.3% coflex vs. 43.9% fusion; adverse event definitely/probably related to the implant: 13.5% coflex vs. 18.7% fusion; adverse event definitely/probably related to the surgery: 23.7% coflex vs. 30.8% fusion; rate of spinous process fracture was 14.0% in the coflex group, however, 48% of these had healed radiographically at 2 years; 0 to 24 months postoperatively, the reoperation rate for coflex was 23/215 (10.7%) compared with 8 of 107 for fusion (7.5%, P = 0.426). Among the 23 patients with re-operations within the coflex group, there were 13 conversion to a primary lumbar fusion, 6 irrigation and debridements for wound-related issues (5 with retention of the device), and 6 revision decompressions (4 with device removal)
Moojen, 2013Prospective, multicenter RCTNetherlandsI159coflexIs interspinous process device implantation more effective in the short term than conventional surgical decompression for patients with intermittent neurogenic claudication due to lumbar spinal stenosisPatients with intermittent neurogenic claudication due to lumbar spinal stenosis after failed conservative treatment (Foraminal Enlargement Lumbar Interspinosus distraXion: FELIX trial); Age: 40 and 85 years with at least three months of intermittent neurogenic claudication due to single or two level degenerative lumbar canal stenosis and an indication for surgeryEight weeks, the success rate according to the Zurich Claudication Questionnaire for the interspinous process device group (63%, 95% confidence interval 51% to 73%) was not superior to that for standard bony decompression (72%, 60% to 81%); repeat surgery rate in the interspinous implant group was substantially higher (n=21; 29%) than that in the conventional group (n=6; 8%) in the early post-surgical period (P<0.001); Surgery time (24 min) was shorter in the interspinous process device group than for bony decompression (43 min) (P<0.001). Blood loss was less in the interspinous process device group (10-50 mL) than in the bony decompression group (50-100 mL) (P<0.001)Five direct (that is, during the initial hospital stay) postoperative complications occurred in the interspinous process device: one patient with short term (48 hours) unexplained visual disturbance, one patient with self limiting pseudoradicular pain in the other leg, and three patients with interspinous process fractures during interspinous process device placement; Direct postoperative complications occurred in six patients in the bony decompression group: two patients with direct epidural hematoma needing reoperation and four patients with dural tears without further consequences. Late re-operation due to absence of recovery was indicated and performed in 21/73 (29%) cases in the interspinous process device group compared with 6/72 (8%) in the bony decompression group (P<0.001)
Tian, 2013Retrospective cohort studyChinaIII32coflexSingle-level (L4-5) implantation of a coflex device for the treatment of lumbar spinal stenosis13 women and 19 men; age: 60.3 years (range 45–75 years); conservative treatment for at least 3 months had failed;32 patients with follow-up times of 24-57 months, HO was detectable in 26 (81.2%). Among these 26 patients, HO was in the lateral space of the spinous process but not in the interspinous space in 8, HO was in the interspinous space but did not bridge the adjacent spinous process in 16, and interspinous fusion occurred at the level of the device in 2No patients needed revision or removal of the implants; no fractures or loosening of the implant occurred
Auerbach, 2013Systematic review using Level I dataUSV1055?coflexInvestigators for the coflex IDE trial classified the severity of adverse events (mild, moderate, or severe) and their relationship to the surgery and device (unrelated, unlikely, possibly, probably, or definitely). An independent CEC, composed of three spine surgeons without affiliation to the study sponsor, reviewed and reclassified all adverse event reports submitted by the investigatorsindependent CEC, composed of three spine surgeons without affiliation to the study sponsor, reviewed and reclassified all adverse event reports submitted by the investigators.CEC reclassified the level of severity, relation to the surgery, and/or relation to the device in 394 (37.3%) of 1055 reported adverse events
Celik, 2012Retrospective cohortTurkeyIII20coflexMicrosurgical bilateral foraminotomy; Co exTM IDD was placed in interspinous space with amount of interspinous distraction.20 patients (9 female and 11 male) with spinal stenosis were included in the study. The mean age was 60 (range 47-74). In 4 patients, L3-L4 level and in 16 patients, L4-L5 level was implantedMean preoperative VAS was 7.85 and fell to 1.7 a month after surgery (p < 0.0001). At the last follow-up the mean VAS score was 1.65 (p < 0.0001). The mean foraminal heights were measured 19.95 mm preoperatively and 25.05 mm a month after surgery (p < 0.0001). The mean foraminal height was 21.60 mm at the last follow-up (p=0.002). The mean lumbar lordosis were measured 32.05 and 34.3 degrees at preoperative and a month after surgery respectively (p=0.155). The mean lumbar lordosis was 32 (±5.99) degrees at the last follow-up (p=0.974)No major complications occurred; 1 superficial wound infection was treated with antibiotics; 1 dural tear was treated with myofascial flap; No implant-related complication was occurred
Maida, 2012Case reportItalyIV1coflexAbnormal osseous tuberosity was subsequently detected surrounding the L4 and L5 spinous processes. The interspinous/interlaminar coflex device implanted at that level was not detectable; resect the new bone formation with a chisel; “U-shaped” part of the device was completely filled by bone; resection of device; dura mater was all covered by interlaminar bone removed using Kerrison rongeurs; gross-total resection of the new bone formation; L4-L5 laminectomy with facet joints preservation and L3, S1 undercutting performed58 year-old man presented with a 6-month history of progressively worsening low back pain; VAS: 8/10; 2008: microsurgical decompressive undercutting and implantation of an interspinous/interlaminar coflex device because of L4-L5 stenosis; 2011: recurrence of motor weakness with the L5 myotome affected, decreased Achilles and patellar reflexes, and neurogenic claudication; mature ossification of the device with relevant restenosisResection of the pathologic bone formation resulted in a rapid neurological recovery (VAS 3/10), and the patient could then walk independently; 2-month followup, the patient had a great reduction in pain and disabilityHO after implantation of an interspinous/interlaminar dynamic device (case report)
Tosteson 2011Cost-effectiveness analysis of a randomized plus observational cohort trialUSI??For SpS, the protocol surgical intervention was a standard posterior laminectomy. For DS, the protocol surgery was the same procedure with or without bilateral single-level fusion with or without instrumentation. For IDH, the protocol surgical intervention was a standard open discectomy18 and older with well-defined symptoms, physical findings and imaging-confirmed diagnosis of spinal stenosis either alone (SpS) or associated with degenerative spondylolisthesis (DS), or diagnosis of intervertebral disc herniation (IDH); A total of 414/ 634 (65.3%) SpS, 391/601 (65.1%) DS and 789/1,192 (66.2%) IDH participants underwent surgerySPS QALY gain 0.22; 95% confidence interval, CI: 0.15, 0.34; DS QALY gain 0.34, 95% CI: 0.30, 0.47; and IDH QALY gain 0.34, 95% CI: 0.31, 0.38; Costs per QALY gained decreased for SPS from $77,600 at 2 years to $59,400 (95% CI: $37,059, $125,162) at 4 years, for DS from $115,600 to $64,300 per QALY (95% CI: $32,864, $83,117), and for IDH from $34,355 to $20,600 per QALY (95% CI: $4,539, $33,088)For SpS, 43 (10.4%) patients underwent 47 additional surgeries; for DS, 48 (12.3%) patients had 52 additional surgeries, and for IDH 70 (8.9%) patients had 82 repeat surgeries. In each case, the majority of repeat surgeries were within 2 years of the initial surgery with a substantial minority occurring after 2 years, including 32.6% of SpS, 20.8% of DS and 24.4% of IDH repeat procedures
Richter, 2010Prospective comparative studyGermanyII60coflexPosterior decompression surgery through a midline approach and micro-surgical bilateral decompression with and without coflex™ inter-spinous device was implanted in one or two levelsAge of 40–80 with one or two level stenosis were included and no previous surgery at the lumbar spine took place. Patients with a stable degenerative spondylolisthesis grade one were includedAll patients increased in function and developed a lower ODI over time, repeated measure ANOVA (F(1) = 63.9; p < 0.001); all patients increased in function and developed a lower RMS over time, repeated measure ANOVA (F(1) = 24.2; p < 0.001); all patients had less pain and lower VAS values over time, repeated measure ANOVA (F(1) = 50,5; p < 0.001); all patients had a prolonged WD over time, repeated measure ANOVA (F(1) = 33.1; p < 0.001)coflex group: one implant-related complication with dislocation of the implant due to fracture of the spinous process; coflex™ group: two revisions with pedicle screw fusion of the segment were necessary; undercutting group: one patient had to be instrumented and fused; both groups we saw one cerebral spinal fluid leak
Weinstein 2010Randomized trial and concurrent observational cohort studyUSI654: 289 (RC) 365 (OC)Standard decompressive laminectomy or standard non-operative careSurgical candidates with a history of at least 12 weeks of symptoms and spinal stenosis without spondylolisthesis (as confirmed on imaging); Age: randomized: 65.5 (10.5), observational: 63.9 (12.5)Randomized and observational cohorts' as-treated treatment effects were similar at 4 years: Bodily Pain: RC 11.4 (95% CI, 5.1 to 17.6) vs. OC 14.9 (95% CI, 9.3 to 20.5), Physical Function: RC 8.0 (95% CI, 1.7 to 14.3) vs. OC 10.1 (95% CI, 4.7 to 15.5), Oswestry Disability Index: RC −7.8 (-12.9, −2.6) vs. OC −11.5 (-15.8, −7.3); clinically significant advantages for surgery previously reported were maintained through 4 years, with treatment effects for BP 12.6 (95% CI, 8.5 to 16.7); PF 8.6 (95% CI, 4.6 to 12.6); and ODI −9.4 (95% CI, −12.6, to −6.2)Most common surgical complication was dural tear (9%). The 4-year reoperation rate was 13%.; Over four years, there were 12 deaths in the non-operative group within 4 years of enrollment compared to 23 expected based on age-gender specific mortality rates, and 15 deaths in the surgery group within 4 years of surgery, compared to 29 expected; All 27 deaths were independently reviewed and 23 were judged not to be treatment-related. Four deaths were of unknown cause and unknown treatment relation but occurred 1203, 1192, 855, 501 days post-surgery/enrollment. Three of these deaths were in patients who had had surgery and one was in a patient who had not had surgery.
Kabir, 2010Systematic review of Level II and Level III studyUnited KingdomIIIEvaluate the current biomechanical and clinical evidence available on the use and effectiveness of lumbar interspinous devices and to recommend indications for their useA systematic review of clinical and bio-mechanical studies was done using the following key words: interspinous implants, interspinous devices, interspinous spacers, dynamic stabilization, X-STOP, coflex, Wallis, DI-AM. The database inclusions were MEDLINE, CINAHL (Cumulative Index to Nursing and Allied Health Literature), and PubMedLargest number of studies has been with the X-STOP device. The biomechanical studies with all the devices showed that ISPs have a beneficial effect on the kinematics of the degenerative spine. Apart from 2 randomized controlled trials, the other studies with the X-STOP device were not of high methodologic quality. Nevertheless, analysis of these studies showed that X-STOP may improve outcome when compared to nonoperative treatment in select group of patients aged 50 or over, with radiologically confirmed lumbar canal stenosis and neurogenic claudication, who have improvement of their symptoms in flexion. Studies on the other devices show satisfactory outcome to varying degrees. However, due to small number and poor design of the studies, it is difficult to clearly define indications for their use in lumbar degenerative disease
Adelt, 2010Retrospective cohortGermanyIIISTUDY IS IN GERMANRetrospective review of patients treated with coflex which match IDE inclusion/exclusion
Cabraja, 2009Case-seriesGermanyIV143Percutaneous facet joint denervation (PFJD). If pain persisted, they were offered implantation of an interspinous device (coflex) and/ or repeat PFJDPatients with verified single level LFJS at level L4–5; Forty-one patients with LFJS at L4–5 underwent PFJD. Twenty patients with persisting pain underwent a subsequent surgery for implantation of an interspinous device. Five patients with recurrent pain at 6–12 months opted for an additional PFJDClinical outcome improved significantly in the surgically treated patients; however, it did not differ compared with patients receiving PFJD only after 24 months; 7-day follow-up: 40 of 41 (98%) patients experienced a relief of back pain greater than 50% according to the VAS; 3 months of follow-up, only 18 of 41 (44%) patients reported of a relief of back pain greater than 50%; defining success as a reduction of 50% or more in the ODI and VAS, only 9 of the 20 (45%) coflex patients were successful on the ODI, and only 7 of 20 (35%) were successful on VAS 2 years after surgery. Using the criteria of 50% reduction in ODI or VAS, similar results were found in the non-surgical patients [8 of 21 (38%) according to ODI and 8 of 21 (38%) according to VAS]Three surgical patients with a secondary poor outcome within 3 months after implantation of a coflex device received an additional posterior semi-dynamic stabilization; No surgical- or device-related complications were observed
Chung, 2009Case-reportKoreaIV1coflexObserved fractures of bilateral inferior articular processes of L4 during operation. Before revision, we chose decompression level of spinal stenosis through selective root block. After, she underwent posterior decompression and posterior segmental fixation from L3 to S164-year-old woman diagnosis of spinal stenosis and degenerative spondylolisthesis at L4-L5; de-compressive laminotomy with instrumentation of interspinous implant (coflex); 6 years later presented with low back pain and radiating pain in left leg; spinal central canal and foraminal narrowing found at L3-L4, L4-L5, and L5-S1; bilateral inferior articular processes of L4; metallic artifact showing interspinous implant/ surrounding fluid collection; perineural adhesion following decompression on central canal and neural foramenSymptoms were relieved after revision; unclear whether interspinous implant increases the possibility of articular process fracture(Case report) Case of bilateral stress fractures of lumbar posterior facet after implantation of interspinous process device; unclear whether previous interspinous process device may cause bilateral stress fracture of posterior facet
Weinstein 2008Randomized trial and concurrent observational cohort studyUSI654: 289 (RC) 365 (OC)Standard posterior decompressive laminectomy OR nonsurgical “usual care:” active physical therapy, education or counseling with home exercise instruction, and the administration of nonsteroidal antiin-flammatory drugs, if tolerated289 randomized cohort; 365 observational cohort; RC 138 surgical group, 151 nonsurgical group; OC: 219 patients initially chose surgery and 146 patients initially chose non-operative care; Surgical candidates with a history of at least 12 weeks of symptoms and spinal stenosis without spondylolisthesis (as confirmed on imaging); Age: randomized: 65.5 (10.5), observational: 63.9 (12.5)Patients who underwent surgery showed significantly more improvement in all primary outcomes than did patients who were treated nonsurgically: as-treated: mean differences in change from baseline in the randomized and observational cohorts were similar at 2 years: bodily pain, 11.7 (95% CI, 6.2 to 17.2) in the randomized group versus 15.3 (95% CI, 10.4 to 20.2) in the observational group; physical function, 8.1 (95% CI, 2.8 to 13.5) in the randomized group versus 13.6 (95% CI, 8.7 to 18.4) in the observational group; and Oswestry Disability Index, −8.7 (95% CI, −13.3 to −4.0) in the randomized group versus −13.1 (95% CI, −16.9 to −9.2) in the observational group; intention-to-treat: surgery : at 2 years mean difference in change from baseline 7.8 (95% confidence interval [CI], 1.5 to 14.1) SF-3610% of patients required transfusions intraoperatively and 5% post-operatively. The most common surgical complication was dural tear, in 9% of patients. At 2 years, reoperation had occurred in 8% of patients; fewer than half of these operations were for recurrent stenosis; At 2 years, there were seven deaths in the nonsurgical group and six in the surgical group, one of which occurred within 3 months after surgery. The deaths were reviewed and 12 were judged not to be treatment-related. The one death of unknown cause occurred 501 days after surgery
Kong, 2007Retrospective cohort studyKoreaIII42coflexPosterior lumbar interbody fusion (PLIF) with interbody cages: Polyether-ether-ketone implants or CH cage, followed by pedicle screw fixation OR Foraminal decompression with partial laminotomy w/ coflex implantPatients having degenerative spinal stenosis with mild segmental instabilit who underwent implantation of coflex™ OR PLIF at L4-5 between January 2000 and December 2003; PLIF: 24 patients 8 males and 16 female patients who ranged in age from 38 to 78 yr (mean 56.0 yr) at the time of surgery; coflex™ group: 18 patients, 3 males and 15 females, who ranged in age from 40 to 71 yr (mean 61.7 yr)Significant improvement in the VAS and ODI scores for lower leg pain and low back pain in both groups (p<0.05), no difference in outcome between two groups;coflex™ group, the PDH on standing radiographs increased significantly from preoperative 7.8 mm to postoperative 9.1 mm (p<0.05), whereas in the PLIF group, the PDH was determined according to the inserted cage size (9-14 mm); ROM at the upper adjacent segment (L3-4) in the PLIF group increased significantly after surgery (p<0.05), whereas the ROM in the coflex™ group did not increase at this levelNo surgical complication in either groups