Survivorship analysis of 150 consecutive patients with DIAM™ implantation for surgery of lumbar spinal stenosis and disc herniation

Brief review

*Title: Survivorship analysis of 150 consecutive patients with DIAM™ implantation for surgery of lumbar spinal stenosis and disc herniation

요추 협착증과 디스크 탈출증으로 DIAM 이식술을 시행한 150명의 환자에 대한 생존 분석

*Authors: Yoo-Joon Sur, Chae-Gwan Kong, Jong-Beom Park

*Bibliography: EurSpine J (2011) 20: 280-288

Background of data

The Device for Intervertebral Assisted Motion (DIAM™) has been introduced for surgery of degenerative lumbar disc diseases.

Purpose

To determine the survivorship of DIAM™ implantation for degenerative lumbar disc diseases and risk factors for reoperation.

Methods

▶Subjects: 150 patients who underwent laminectomy or discectomy with DIAM™ implantation (84 males + 66 females)

▶Mean age: 46.5 years;

▶Mean follow-up period: 23 months (range 1–48 months)

▶Indications: 96 spinal stenosis and 54 disc herniations

▶Index level: 146 one-level (L4–5: 115/ L5–6: 31) and 4 two-level (L4–5 and L5–6)

▶Evaluating methods:

1. Kaplan–Meier analysis: To determine the cumulative reoperation rate and survival time

2. The log-rank test and Cox regression model: To evaluate the effect of age, gender, diagnosis, location, and level of DIAM™ implantation

-Reoperations of the DIAM™ implantation level or adjacent levels were defined as a failure and used as the end point for determining survivorship.

Results

▶Reoperation rate: 4.7% (total 7 patients- only implantation level)

▶The causes of reoperation:

1. recurrent spinal stenosis (n=3)

2. recurrent disc herniation (n=2)

3. post-laminectomy spondylolisthesis (n=1)

4. delayed deep wound infection (n=1)

▶The mean time interval (from 1st to 2nd surgery): 13.4 months (range 2–29 months)

▶Kaplan–Meier analysis: predicted an 8% cumulative reoperation rate 4 years post-operatively.

Survival time was predicted to be 45.6 ± 0.9 months.

▶In Log-rank test, the reoperation rate: L5–6 > L4–5 (p = 0.002)

two-level > one-level (p = 0.01)

-Gender, age, diagnosis did not significantly affect the reoperation rate of DIAM™ implantation.

-Based on a Cox regression model, L5–6 and two-level DIAM™ implantation were also significant variables associated with a higher reoperation rate.

(L5–6: hazard ratio (HR) 10.3, 95% CI, 1.7–63.0; p = 0.01 / HR, 10.4; 95% CI, 1.2–90.2; p = 0.04)

-Survival time was significantly lower in L5–6 (47 vs. 22 months, p = 0.002) and two-level DIAM™ implantation (46 vs. 18 months, p = 0.01) compared with L4–5 and one-level DIAM™ implantation.

Conclusions

-8% patients who have a DIAM™ implantation for primary lumbar spinal stenosis or disc herniation are expected to undergo reoperation at the same level within 4 years after surgery.

-DIAM™ implantation at L5–6 and two-level are significant risk factors for reoperation.

Percutaneous interspinous spacer versus open decompression: a 2-year follow-up of clinical outcome and quality of life.

Brief review

이 논문은 척추의 극돌기 사이에 spacer라고 하는 확장기를 삽입하는 수술과 기존의 개복을 통한 감압수술(요추3-4번 혹은 요추 4-5번)을 받은 45명의 환자를 대상으로 각각 2년간의 추적조사를 통해 임상적 결과와 삶의 질을 비교하는 내용 입니다. 
수술 후의 삶의 질, 일상생활 가능 정도, 보행거리 등을 평가하였으며 2년간 대상 환자들을 추적조사한 결과, 극돌기간 확장기 삽입술을 시행한 환자들에 비해 개복 감압술을 시행한 환자들이 모든 평가항목에서 우수한 결과를 보였습니다.

*Title: Percutaneous interspinous spacer versus open decompression: a 2-year follow-up of clinical outcome and quality of life.

극돌기간 경피적 확장기 삽입술 대 개복 감압술: 2년간의 임상적 결과와 삶의 질 추적조사

*Author: Beyer F, Yagdiran A, Neu P, Kaulhausen T, Eysel P, Sobottke R.

*Bibliography: Eur Spine J. 2013 Sep;22(9):2015-21.

PURPOSE

-To compares the effectiveness of Percutaneous interspinous stand-alone spacers and open decompressive surgery.

-To determine the validity of using percutaneous interspinous spacer.

METHODS

▶Study type: Open prospective non-randomized study

▶Inclusion criteria: symptomatic lumbar stenosis between L3 and L5

Exclusion criteria: undergone previous surgery at the investigated level

▶Subject number: 45 patients

▶Divided 2 groups

-Group 1: underwent percutaneous interspinous stand-alone spacers (n = 12)

-Group 2: underwent bilateral open microsurgical decompression (n = 33)

▶Evaluation parameter:

1. patient data (using “Spine Tango” register; data collecting system)

2. operative report (contains disease, surgery information, complications)

3. Core Outcome Measures Index (COMI)**

4. SF-36 :Physical Component Summaries(PCS)**, Mental Momponent Summaries(MCS)**

5. Oswestry Disability Index (ODI)

6. Visual Analog Scale (VAS)

7. walking distance

▶Follow-up time: 6 weeks, 3, 6, 9, 12, 24 months post-surgery

RESULTS (after 2 yrs)

▶Revision -In group1: 5patients required implant removal and open decompression

                - In group2: none

▶Blood loss: group1<500ml

          500ml<group2<1000ml

▶Average speed of walking tolerance: 1.5km/h (improved for both groups)

▶Clinical outcome(VAS, ODI): group 1<group 2

▶Quality Of Life(SF-36-PCS/MCS): group 1<group 2

CONCLUSION

-Decompression proved superior to percutaneous stand-alone spacer implantation in our two observational cohorts.

-Recommend Interspinous spacer implantation only within randomized controlled trials for the collection of reliable data and conclusions for the spine surgeon.

Does the presence of the nerve root sedimentation sign on MRI correlate with the operative level in patients undergoing posterior lumbar decompression for lumbar stenosis?

Brief review 1

*Title: Does the presence of the nerve root sedimentation sign on MRI correlate with the operative level in patients undergoing posterior lumbar decompression for lumbar stenosis?

*Authors: Akil Fazal, MD,  Andrew Yoo, BA,  John A. Bendo, MD

*Bibliography: Spine J. 2013 Aug;13(8):837-42.

BACKGROUND CONTEXT:

-Recent research describes the use of a nerve root sedimentation sign to diagnose lumbar spinal stenosis (LSS).

-The lack of sedimentation of the nerve roots (positive sedimentation sign) to the dorsal part of the dural sac is the characteristic feature of this new radiological parameter.

PURPOSE: To demonstrate how the nerve root sedimentation sign compares with other more traditional radiological parameters in patients who have been operated for LSS.

STUDY DESIGN/SETTING: A retrospective chart and image review.

PATIENT SAMPLE: Preoperative MRI were reviewed from 71 consecutive operative patients who presented with LSS and received spinal decompression surgery (2006-2010).

OUTCOME MEASURES: Preoperative T2-weighted MRIs were reviewed for each patient.

METHODS:

▶Measurements

134 vertebral levels (L1-5) were measured for

1)     sedimentation sign

2)     cross-sectional area (CSA)

3)     anterior/posterior (A/P) diameter of the dural sac

4)     thickness of the ligamentum flavum

5)     Fujiwara grade of facet hypertrophy.

-using Surgimap 1.1.2.169 software (Nemaris, Inc., New York, NY, USA)

-Exclusion criteria: 1) previous spine surgeries 2) absence of MRI on extended dynamic range 3) surgeries for primary diagnosis other than LSS

▶Statistical analyses

-using the SPSS 17.0 statistical software (SPSS Inc., Chicago, IL, USA).

-Significance was demonstrated using unpaired t tests and chi-squared tests.

RESULTS: The measurements are listed below.

CONCLUSIONS:

-The sign is most often present in patients who have clinically significant lumbar stenosis and require surgery.

-The sedimentation sign is a new measurement tool that can enable physicians to objectively assess and quantify spinal stenosis.

*Fujiwara grading system: aim to assess the severity of the facet joint osteoarthritis.

REFERENCE: Fujiwara A, Tamai K, Yamato M, et al. The relationshipbetween facet joint osteoarthritis and disc degeneration of the lumbar spine: anMRI study. Eur Spine J 1999;8:396–401.