Decompression and Coflex interlaminar stabilization compared with decompression and instrumented spinal fusion for spinal stenosis and low-grade degenerative spondylolisthesis

Brief review

*Title: Decompression and Coflex interlaminar stabilization compared with decompression and instrumented spinal fusion for spinal stenosis and low-grade degenerative spondylolisthesis

:two-year results from the prospective, randomized, multicenter, Food and Drug Administration Investigational Device Exemption trial.

요추 협착증과 낮은 단계의 퇴행성 척추전방전위증 치료를 위한 감압술 & Conflex(고정체)를 이용한 추궁간판 안정화술과 감압술 & 요추유합술 비교.

:전향적, 무작위배정, 다기관, FDA-IDE연구

*Authors: Davis RJ, Errico TJ, Bae H, Auerbach JD.

*Bibliography: Spine (Phila Pa 1976). 2013Aug 15;38(18):1529-39.

STUDY DESIGN

Prospective, randomized, multicenter, Food and Drug Administration Investigational Device Exemption trial (FDA- IDE)

OBJECTIVE

To evaluate the safety and efficacy of Coflex interlaminar stabilization compared with posterior spinal fusion in the treatment of 1- and 2-level spinal stenosis and degenerative spondylolisthesis.

SUMMARY OF BACKGROUND DATA

Lumbar fusion for stenosis and degenerative spondylolisthesis have led to the search for motion-preserving, less-invasive alternatives.

METHODS

▶Subject: total 322 patients (2006~2010)

-Randomized to receive laminectomy & Coflex interlaminar stabilization(215) or laminectomy & posterolateral spinal fusion(107)   -->2:1 ratio

▶Evaluating methods: ODI, reoperations, complications, postoperative epidural injections

RESULTS

▶Follow-up: 95.3% (Coflex) / 97.2% (fusion) –min 2 yrs.

▶Results:

-Operative times: conflex < fusion

- blood loss: conflex < fusion

- length of stay: conflex < fusion

-ODI improvement: conflex > fusion

-VAS improvement: both groups

-SF-12 improvement: conflex > fusion

-Zurich Claudication Questionnaire

-Reoperation rate: conflex (10.7%) > fusion (7.5%) (p = 0.426)

-Overall success rate: Coflex (66.2%) > fusion (57.7%) (p = 0.999) -Based on the FDA.

>Coflex significantly improve in all outcomes measures compared with fusion: symptom severity (p = 0.023); physical function (p = 0.008); satisfaction (p = 0.006)

>At 2 yrs, fusions increased angulation (P = 0.002) and a trend toward increased translation (p= 0.083) at the superior adjacent level. Whereas Coflex maintained normal operative and adjacent level motion.

CONCLUSION

Coflex interlaminar stabilization is a safe and efficacious alternative compared with lumbar spinal fusion for spinal stenosis and low-grade spondylolisthesis.

Two-year results of interspinous spacer (X-Stop) implantation in 175 patients with neurologic intermittent claudication due to lumbar spinal stenosis

Brief Review

이 논문은 요추협착증 때문에 신경이 간헐적으로 파행되어 척추 극돌기간에 X-Stop이라고 하는 고정체를 삽입한 환자들을 2년간 추적조사한 내용 입니다.

X-Stop 삽입술을 시행한 환자 175명을 대상으로 VAS, ODI를 조사한 결과 수술 후 6주, 2년이 지난 시점에서의 평균VAS는 통계적으로 유의하게 감소하였고, 평균ODI는 유의하게 향상되었습니다.

X-Stop삽입술은 심한 협착증이 있을 경우에는 미세 수술적 감압술을 대체할 수는 없지만 몇몇 특정한 협착증 환자에게는 안전하고 효과적이며 덜 침습적인 수술방법이 될 수 있다는 결론 입니다.

Surgical technique등의 상세한 내용은 아래의 Bibliography에 링크된 저널 홈페이지에서 확인하세요!

*Title: Two-year results of interspinous spacer (X-Stop) implantation in 175 patients with neurologic intermittent claudication due to lumbar spinal stenosis.

요추 협착증 때문에 신경이 간헐적으로 파행된 175명의 환자에 대해 극돌기간 고정체 삽입술을 시행한 후 2년의 결과

*Authors: Johannes Kuchta, Rolf Sobottke, Peer Eysel, Patrick Simons

*Bibliography: Eur Spine J. 2009 Jun;18(6):823-9.

Background of data

The X-Stop is the most commonly used interspinous distraction device in patients with neurogenic intermittent claudication due to LSS.

Methods

▶Subject: 175 patients an X-Stop implanted in 1 or 2 level (2003~2007)

▶Evaluating method(clinical): VAS (leg pain), ODI (Oswestry disability index)

-follow-up period: up to 4 years

       

Results

▶Mean VAS

61.2% (pre) --> 39.0% (6weeks)--> 39.0% (24 months)

▶Mean ODI

32.6% (pre) --> 22.7% (6weeks)--> 20.3% (24 months)

-8 patients had to be removed and performed microsurgical decompression because of unsatisfactory effect of the X-Stop implanted surgery.

-This study results indicate satisfactory short-term and good long-term effect during a follow-up period of 2 years.

-Functional MRI examinations provide helpful, positional-dependent preoperative information.

Conclusions

-Implantation of the X-Stop device is a minimally invasive, effective and safe procedure.

-The interspinous device does not replace microsurgical decompression in patients with massive stenosis and continuous claudication, but offers a save, effective and less invasive alternative in selected patients with spinal stenosis.

-Functional (upright-) MRI examinations were able to demonstrate the positional-dependent stenosis.

Quality-adjusted life year (QALY) & Incremental Cost-Effectiveness Ratio (ICER)

1. Quality-adjusted life year (QALY)란?

-어떠한 의학적 처치(intervention)등으로 인해 추가적으로 얻게 되는 삶(수명)을 질적, 양적으로 평가하는 수치/unit  (수술cost와는 직접적인 연관은 없음)

-평가방법: 질적 가치 * 양적 가치

>질적 가치: SF-6D를 통해 평가(삶의 질)

>양적 가치: SF-6D로 평가된 삶의 질을 보장하는 시간(연도)

*SF-6D: 삶의 질 평가도구로, 일반적으로 의학논문에서 임상적 평가도구로서 삶의 질을 알아볼 때에 많이 사용되는 SF(Short Form)-36에서 Physical/Social Functioning, Role Participation, Bodily Pain, Mental Health, Vitality와 관련된 11문항을 선정한 평가방법이다.

참고자료 링크

<예시1>

그림출처: http://statbemotion.tistory.com/m/post/view/id/212

2. Incremental Cost-Effectiveness Ratio (ICER) 란?

-QALY 증가에 따른 추가 가격으로, 의학적 intervention의 효과가 한 단위 증가 하는 데에 드는 비용을 말함.

-Cost per Quality-adjusted life year (cost/QALY)

(특정 intervention의 질적,양적인 가치 대비 소요비용- 어떤 치료를 선택하게 되면 예상되는 기간 동안의 삶의질 향상 대비 사용 될 비용의 가치 평가)

-건강경제에서 주로 사용되는 개념

<예시2>

-치료A와 B비교

70세의 사람에게 치료A를 할 경우 73세에 죽고, 그 3년간의 삶의 질 정도를 0.5로 보장한다고 해보자.

그리고 치료B를 할 경우, 평균수명을 2살 연장시켜 75세에 죽게 하고, 그 5년 간의 삶의 질도 0.6으로 증가했다고 가정 해보자.

▶치료 A가 아니라 B를 선택한다면,  (5 * 0.6) - (3 * 0.5)  = 3.0 - 1.5 = 1.5 (QALYs)

즉 1.5 QALYs를 얻게 된다.

그런데 치료A 의 금액이 10000$ 이고 치료B의 가격이 55000$ 이라고 한다면 45000$이 추가 발생 한 것이다.

위의 식으로 평가하면 ICER에서 치료B는 치료A에 비해 45000 $ / 1.5 QALY, 즉 30000$ per QALY 의 비용이 나온다.

-->즉 1년의 QALY를 얻는데 30000$의 비용이 든다는 것이다.

>참고 문헌

1. Loomes G , McKenzie L . The use of QALYs in health care decision making. Soc Sci Med 1989 ; 28 : 299 – 308.

2. Brazier J , Roberts J , Deverill M . The estimation of a preference-based

measure of health from the SF-36. J Health Econ 2002 ; 21 : 271 – 92 .

3. Paul A. Scuffham, Jennifer A. Whitty, Andrew Mitchell, Rosalie Viney. The Use of QALY Weights for QALY Calculations. Pharmacoeconomics2008; 26 (4): 297-310

4. Leah Y. Carreon, Paul A. Anderson, Vincent C. Traynelis, Praveen V. Mummaneni, Steven D. Glassman. Cost-effectiveness of single-level anterior cervical discectomy and fusion five years after surgery. Spine(Phila Pa 1976). 2013 Mar 15;38(6):471-5.

>참고 사이트

http://en.wikipedia.org/wiki/Quality-adjusted_life_year

http://statbemotion.tistory.com/m/post/view/id/212

http://statbemotion.tistory.com/m/post/view/id/213

Cost-effectiveness of single-level anterior cervical discectomy and fusion five years after surgery

Brief review

*Title: Cost-effectiveness of single-level anterior cervical discectomy and fusion five years after surgery

단일분절 전방경유 경추 절제 및 유합술 후 5년 간의 비용 효율성

*Authors: Leah Y. Carreon, Paul A. Anderson, Vincent C. Traynelis, Praveen V. Mummaneni, Steven D. Glassman

*Bibliography: Spine (Phila Pa 1976). 2013 Mar15;38(6):471-5.

STUDY DESIGN

Longitudinal cohort

OBJECTIVE

To determine the cost per quality-adjusted life year(cost/QALY) gained for single-level instrumented anterior cervical discectomy and fusion(ACDF) over 5 years.

SUMMARY OF BACKGROUND DATA

Economic value is an increasingly important component of health care policy decision making.

METHODS

Control patients: undergone ACDF (5 yr follow-up)

Direct costs: using the 2012 Medicare Fee schedule.

Health utility: Short Form-6D. (SF-36에서 몇 가지 항목을 발췌하여 수정한 설문지.)

RESULTS

▶Subject number: 352 patients (182 women+170 men)

▶Mean age: 44.6 yrs (22-73 yr)

▶Cost per patient(ACDF): $15,714

-41 repeat ACDFs, 15 posterior fusions, 6 foraminotomies, 2 implant removals, 2 hematoma evacuations, and 1 esophageal fistula repair were performed

▶Mean QALY:

-1yr fu: 0.16

-2yr fu: 0.18

-3yr fu: 0.17

-4yr fu: 0.18

-5yr fu: 0.18

-cumulative QALY over 5 yrs: 0.88

▶resultant cost/QALY

-1yr: $104,831

-2yr: $53,074

-3yr: $37,717

-4yr: $28,383

-5yr: $23,460

In this cohort, 11 nerve releases and 26 rotator cuff repairs were done within 5 years after the index ACDF.

CONCLUSION

Increasing health care costs call for demonstration of cost-effectiveness in order to justify payment for interventions, including ACDFs.

This study indicates that at 5-year follow-up, single-level instrumented ACDF is both effective and durable resulting in a favorable cost/QALY gained as compared to other widely accepted health care interventions.