Risk Factors of Pulmonary Complications After Minimally Invasive Surgery for Elderly Patients with Vertebral Compression Fractures

Figures & data

Table 1 Univariate Analysis of Related Factors Between Patients with and Without Pulmonary Complications

Risk Factors	PC (n=27)	NPC (n=206)	Odds Ratio	95% CI	P-value
Gender
Male	11	58	1.754	0.768–4.005	0.178
Female	16	148
Age	78.89±7.65	75.56±6.62		0.606–6.046	0.017
BMI	25.19±2.84	23.56±3.05		0.397–2.841	0.01
Smoking
Yes	11	47	2.326	1.010–5.354	0.043
No	16	159
Alcohol abuse
Yes	4	35	0.85	0.277–2.610	0.992
No	23	171
Diabetes
Yes	6	36	1.349	0.508–3.580	0.736
No	21	170
Cardiovascular diseases
Yes	19	99	2.567	1.075–6.128	0.029
No	8	107
Prior spine surgery
Yes	5	58	0.58	0.210–1.604	0.289
No	22	148
Surgical procedure
PKP	9	47	1.691	0.713–4.012	0.229
PVP	18	159
Surgical site
Thoracic	11	86			0.78
Lumbar	13	105
Thoracic + Lumbar Lumbar Lumbar Lumbar	3	15
Surgical levels
1	22	151	1.603	0.579–4.440	0.361
≥ 2	5	55
Older fractures
Yes	7	20	3.255	1.226–8.643	0.031
No	20	186
Preoperative LOS	2.85±3.49	1.92±1.72		−0.470–2.329	0.185
Total LOS	5.59±4.72	5.79±6.49		−2.741–2.354	0.881
Grade of VSA
≤ 5	22	158	1.337	0.480–3.711	0.577
> 5	5	48

Abbreviations: PC, pulmonary complications; NPC, no pulmonary complications; CI, confidence intervals; BMI, body mass index; PKP, percutaneous kyphoplasty; PVP, percutaneous vertebroplasty; LOS, length of stay; VSA, visual analogue score.

Table 2 Unconditional Binary Logistic Regression Analysis of Risk Factors for Pulmonary Complications

Risk Factors	β	OR	95% CI	Standardized Error	Wald χ^2	P-value
BMI	1.032	2.807	1.14–6.94	0.462	4.999	0.025
Cardiovascular diseases	1.622	5.065	1.72–14.88	0.550	8.710	0.003
Older fractures	1.214	3.368	1.45–7.83	0.431	7.951	0.005

Abbreviations: CI, confidence intervals; BMI, body mass index.

Table 3 Risk Assessment Scale of Pulmonary Complications After Minimally Invasive Surgery for Elderly Patients with VCFs

Stage	Items	Grading Rules and Scores			Score
		1	2	3
Preoperative assessment	1. Age (years)	65–74	75–84	≥ 85
	2. BMI	18–23	24–29	≥ 30, < 18
	3. Smoking duration (years)	< 10	11–20	≥ 21
	4.1 Combined diseases (number)	1	2	≥ 3
	4.2 Chronic pulmonary diseases	Yes
	5. Duration of VCFs (days)	≤ 7	8–20	≥ 21
	6. Bed rest duration (days)	≤ 7	8–20	≥ 21
	Preoperative assessment scores
Postoperative assessment	7. Preoperative LOS	1	2	≥ 3
	8. Type of anesthesia	Local	Spinal	General
	9. Duration of operation (minutes)	> 30	> 60	> 90
Total scores

Abbreviations: BMI, body mass index; Combined diseases, diabetes mellitus, chronic cardiovascular and cerebrovascular diseases; LOS, length of stay.

Figure 1 Area under the curve of the predicted meaningful and risk factors.

Table 4 Scores of 53 Patients Assessed by Assessment Table

Variable	Assignment	PC (5 Cases)	NPC (48 Cases)
Gender	Male	3	9
	Female	2	39
Age (years)	65–74	1	28
	75–84	2	14
	≥ 85	2	6
BMI	18–23	1	12
	24–29	4	34
	≥ 30, < 18	0	2
Smoking duration (years)	No smoking	2	36
	< 10	0	6
	10–20	3	1
	≥ 21	0	5
Combined diseases (number)	1	0	12
	2	2	12
	3	0	6
	≥ 3	3	7
Chronic pulmonary diseases	Yes	3	2
Duration of VCFs (days)	≤ 7 days	1	20
	7–20	1	17
	≥ 21	3	11
Bed rest duration (days)	≤ 7 days	3	41
	7–20	0	7
	≥ 21	2	0
Preoperative LOS	1	2	25
	2	0	10
	≥ 3	3	13
Type of anesthesia	Local anesthesia	5	48
	Spinal anesthesia	0	0
	General anesthesia	0	0
Duration of operation (minutes)	> 30 mins	3	39
	> 60 mins	2	9
	> 90 mins	0	0

Abbreviations: Combined diseases, diabetes mellitus, chronic cardiovascular and cerebrovascular diseases; VCFs, vertebral compression fractures; LOS, length of stay; PC, pulmonary complications; NPC, no pulmonary complications.

Table 5 Test Result Variable(S): Preoperative Risk Assessment Values

Positive If Greater Than or Equal To^a	Sensitivity	1 – Specificity
3.00	1.000	1.000
4.50	1.000	0.979
5.50	1.000	0.917
6.50	1.000	0.667
7.50	1.000	0.479
8.50	1.000	0.396
9.50	1.000	0.250
10.50	1.000	0.167
11.50	0.600	0.083
12.50	0.200	0.042
14.00	0.200	0.000
16.00	0.000	0.000

Notes: The test result variable(s): Preoperative has at least one tie between the positive and negative actual state groups. ^aThe smallest cutoff value is the minimum observed test value minus 1, and the largest cutoff value is the maximum observed test value plus 1. All the other cutoff values are the averages of two consecutive ordered observed test values.

Table 6 Test Result Variable(S): Total Risk Assessment Values

Positive If Greater Than or Equal To^a	Sensitivity	1 – Specificity
6.00	1.000	1.000
7.50	1.000	0.979
8.50	1.000	0.938
9.50	1.000	0.750
10.50	1.000	0.625
11.50	1.000	0.479
12.50	1.000	0.396
13.50	1.000	0.292
14.50	1.000	0.229
15.50	0.800	0.146
16.50	0.600	0.063
17.50	0.200	0.021
18.50	0.200	0.000
20.00	0.000	0.000

Notes: The test result variable(s): Total has at least one tie between the positive and negative actual state groups. ^aThe smallest cutoff value is the minimum observed test value minus 1, and the largest cutoff value is the maximum observed test value plus 1. All the other cutoff values are the averages of two consecutive ordered observed test values.

Figure 2 Area under the curve of preoperative risk assessment values.

Figure 3 Area under the curve of total risk assessment values.