Incidence and Risk Factors for Adjacent Segment Disease After Transforaminal Lumbar Interbody Fusion in Patients with Lumbar Degenerative Diseases

Figures & data

Table 1 Characteristics of the Patients

Variable	n=1258
Age (y)	56.4±12.4 (20–87)
Male/female ratio	566/692
Follow-up period (mo.)	35.0±17.8 (24–123)
Fusion segments
Single (n)	988
Double (n)	270
Average segments (n)	1.2±0.4
Pathology
DS/SO (n)	438
LSS (n)	260
LDH (n)	560

Abbreviations: DS, degenerative spondylolisthesis; SO, isthmic spondylolisthesis; LSS, lumbar spinal stenosis; LDH, lumbar disc herniation.

Table 2 Characteristics of the Patients with ASD

Variable	ASD: n=65
Age (y)	59.1±11.4
Male/female ratio	29/36
Follow-up period (mo.)	75.4±23.6
ASD onset delay (mo.)	68.3±25.1
Primary surgery segment
L2–L4	2
L3–L4	2
L3–L5	6
L4–L5	37
L4–S1	4
L5–S1	14
ASD position
Cranial	46
Caudal	16
Both	3
ASD segment
L2/3	2
L2/3, L3/4	1
L2/3, L5/S1	2
L3/4	30
L3/4, L5/S1	1
L4/5	17
L5/S1	12
ASD surgical strategy
TLIF	43
OLIF	8
PELD	12
MED	2

Abbreviations: ASD, adjacent segment disease; TLIF, transforaminal lumbar interbody fusion; OLIF, oblique lumbar interbody fusion; PELD, percutaneous endoscopic lumbar discectomy; MED, microendoscopic discectomy.

Table 3 Comparison of Demographic and Surgical Parameters Between the ASD Group and N-ASD Group

Variable	ASD (n=65)	N-ASD (n=200)	t/Z	P value
Age (y)	59.1±11.4	56.0±11.9	1.874	0.062
Sex			0.195	0.659
Male	29	83
Female	36	117
BMI (kg/m^2)	27.3±2.2	23.4±2.3	11.945	0.000
Hypertension (Y/N)	22/43	37/163	6.675	0.010
DM (Y/N)	14/51	24/176	3.634	0.057
Smoking (Y/N)	9/56	23/177	0.254	0.614
BMD			5.344	0.069
Normal	45	165
Osteoporosis	7	11
Severe osteoporosis	13	24
Operative time (min)	122.9±29.2	114.6±31.1	1.907	0.058
Blood loss (mL)	191.1±85.4	189.9±112.8	0.077	0.939
Fixed segments (n)	2.2±0.5	2.2±0.4	0.348	0.728
Fusion segments (n)	1.2±0.4	1.2±0.4	0.088	0.930

Abbreviations: BMI, body mass index; DM, diabetes mellitus; BMD, bone mineral density.

Table 4 Comparison of Radiological Variables Between the ASD Group and N-ASD Group

Variable	ASD (n=65)	N-ASD (n=200)	t/Z	P value
Preoperative adjacent segment disc degeneration
I	0	53	96.923	0.000
II	4	90
III	28	49
IV	28	8
V	5	0
Preoperative adjacent segment intervertebral height	11.4±1.6	13.1±1.5	−8.172	0.000

Table 5 Logistic Regression Analysis of Risk Factors in ASD Patients

Variables	B	SE	Wald	P value	OR	95% CI
Body mass index, BMI	0.729	0.146	24.984	0.000	2.073	1.558–2.759
Preoperative adjacent segment disc degeneration	1.807	0.340	28.197	0.000	6.093	3.127–11.871
Preoperative adjacent segment intervertebral height	−0.338	0.160	4.465	0.035	0.713	0.521–0.976

Figure 1 The incidence (A) and onset delay (B) of ASD between the three types of lumbar degenerative diseases. No difference was seen in the ASD incidence or ASD onset time.

Figure 2 Type case: Male, 49 y, with L5/S1 lumbar disc herniation, degeneration of the L4/5 intervertebral disc before the operation, and Pfirrmann grade IV (A and B). Transforaminal lumbar interbody fusion (C and D) was performed on lumbar 5/sacral 1 in February 2013, which significantly relieved his symptoms. In January 2018, the patient developed numbness and pain in the left lower extremity. Lumbar intervertebral disc MRI showed that the L4/5 disc was herniated and compress the left nerve root (E and F). He was diagnosed with adjacent segment disease. L4/5 was treated by transforaminal lumbar interbody fusion (G and H), which significantly relieved the symptoms.