Clinical and Radiologic Outcomes of TLIF Applications With or Without Pedicle Screw: A Double Center Prospective Pilot Comparative Study

Brief review

*Title: Clinical and Radiologic Outcomes of TLIF Applications With or Without Pedicle Screw: A Double Center Prospective Pilot Comparative Study

척추경나사 사용 유무에 따른 추간공경유 요추 유합술의 임상적, 방사선학적 결과

: 두 기관의 예비 전향적 비교 연구

*Author: Kadir Kotil, Mustafa Ali Akc¸etin, Yildiray Savas

*Bibliography: J Spinal Disord Tech. 2013Oct;26(7):359-66.

STUDY DESIGN

Prospective cohort data by merging data from comparative studies.

OBJECTIVE

To compare clinical and radiologic outcomes of the transforaminal lumbar interbody fusion (TLIF) procedure with or without pedicle screw support in stable patients with a degenerative disease.

SUMMARY OF BACKGROUND DATA

-TLIF is routinely performed with the support of pedicle screws.

-Problem: TLIF procedure without pedicle screw support has not yet been reported.

METHODS

▶Period: 2006.02 ~ 2009.05

▶Subject: patients underwent decompression and fusion (using TLIF)

-Group A: TLIF with pedicle screw (n=30)

-Group B: TLIF without pedicle screw (n=30)

▶Mean follow-up period: 31mon

▶Mean age: 45.5 yrs

RESULTS

	group A	group B
Sex ratio (female: male)	19:11	18:12
Pseudoarthrosis (patients)	2	3
Mean operating time (min)	110	73
Mean blood loss (mL)	410	220
Cage loosening (patients)	0	1
sciatic pain	4	1

-VAS, ODI (after 1months):  A > B (P<0.005)

                 (after 3 months): Not significantly differ (P<0.89).

-Cost: A(3-fold higher) > B

CONCLUSIONS

-TLIF procedure without pedicle screw would be sufficient in the management of stable patients with lumbar degenerative disease after single-level decompression.

-And this technique is less costs and complications compared with pedicle screwing.

Influence of bone mineral density on pedicle screw fixation: a study of pedicle screw fixation augmenting posterior lumbar interbody fusion in elderly patients

Brief review

*Title: Influence of bone mineral density on pedicle screw fixation: a study of pedicle screw fixation augmenting posterior lumbar interbody fusion in elderly patients

척추경나사못고정술에서 골밀도의 영향: 고령환자의 후방 요추체간 유합술에서 척추경 나사못 고정의 연구

*Author: Koichiro Okuyama, Eiji Abe, Tetsuya Suzuki, Yasuki Tamura, Mitzuho Chiba, Kozo Sato

*Bibliography: TheSpine Journal1(2001)402-407.

Background context: 

-Some biomechanical studies have demonstrated that bone mineral density of the lumbar spine (BMD) affects the stability of pedicle screws in vitro.

-Common problem: screw bending, breakage, loosening(radiolucency in the bone screw interface).

Purpose: 

-To investigate influence of BMD on loosening and related failure of pedicle screws in vivo.

Study design/setting: 

-A clinical study of 52 patients who underwent pedicle screw fixation augmenting posterior lumbar interbody fusion (PLIF).

Patient sample:

▶Subject number: 52 patients (13 men + 39 women)

▶Mean age: 63 years (range, 45–76 yr)

▶Mean follow-up period: 2.8 years (range, 2–6 yr).

Outcome measures: 

-statistically analyzed(Relationship between BMD, screw loosening, and its related failures)

Methods:

-BMD was measured by the dual energy X-ray absorptiometry (DEXA) method.

-Two authors did radiographic assessments.

▶52 patients were divided into 3 groups as below.

1. Union: n=40

(no movement on the lateral view in the flx-ext in the fixed segment and continuity of trabecular bony bridging at the fixed interbody space.)

2. Non union: n=4

(any movement or discontinuity)

3. Undetermined union: n=8

(continuity of the trabecular bony bridging was vague in spite of no movement of the fixed segment in the flx-ext.)

Results:

The mean BMD values are as follow. (Unit: g/cm2 / mean±S.D.)

▶All patients: 0.879±0.215

▶Patients with or without screw loosening

-with screw loosening: 0.720±0.078 (n=11)

-without screw loosening: 0.922±0.221 (n=41).

>>Significant difference between with and without screw loosening 

(the mean BMD of patients ,P<.01).

▶Union patients

-Union patients: 0.934±0.210 (n=40)

-Non union: 0.674±0.104 (n=4)

-Undetermined union: 0.710±0.116 (n=8)

>>Union was significantly greater than those with Nonunion and Undetermined union (P<.05).

Conclusion:

-BMD has a close relation with the stability of pedicle screws

-BMD value below 0.674±0.104 g/cm2 suggests a potential increased risk of “nonunion” when pedicle screw fixation is performed in conjunction with PLIF.