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2013년 12월 23일 월요일

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.




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.

2013년 12월 12일 목요일

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

Brief Review

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, ODI 조사한 결과 수술 6, 2년이 지난 시점에서의 평균VAS 통계적으로 유의하게 감소하였고, 평균ODI 유의하게 향상되었습니다.

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

Surgical technique등의 상세한 내용은 아래의 Bibliography 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 2년의 결과

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




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.

2013년 12월 10일 화요일

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



1. Quality-adjusted life year (QALY)?

-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.


<예시1>






















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>
-치료A B비교

70세의 사람에게 치료A를 할 경우 73세에 죽고, 3년간의 삶의 질 정도를 0.5로 보장한다고 해보자.
그리고 치료B를 할 경우, 평균수명을 2살 연장시켜 75세에 죽게 하고, 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)
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, 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


2013년 12월 8일 일요일

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 유합술 5 간의 비용 효율성
*Authors: Leah Y. Carreon, Paul A. Anderson, Vincent C. Traynelis, Praveen V. Mummaneni, Steven D. Glassman


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.