Predicting Length of Stay After Thoracolumbar Trauma: A Single-Center, Retrospective Analysis

Justin E. Kung; Jael E. Camacho; Jacob Bruckner; Ivan B. Ye; Alexandra E. Thomson; Daniel Cavanaugh; Eugene Y. Koh; Daniel E. Gelb; Charles Sansur; Steven C. Ludwig

doi:10.14444/8242

Article Figures & Data

Figures

Tables

Download figure
Open in new tab
Download powerpoint
Figure 1
Flowchart of patients included in the study.
Download figure
Open in new tab
Download powerpoint
Figure 2
Scatter plots of natural log (ln)-transformed length of stay (LOS) and LOS predicted by model 1 and 2 vs actual ln-transformed LOS and LOS. (a) Model 1 vs actual: ln-transformed LOS; (b) model 1 vs actual: LOS; (c) model 2 vs actual: ln-transformed LOS; (d) model 2 vs actual: LOS.

Tables

Figures

View popup

Table 1

Bivariate analysis of demographic variables and LOS.

Demographic	Mean ± SD^{^a}	Spearman ρ	P Value^{^b}
Age	45.7 ± 19.7	0.13	0.07
Body mass index	27.5 ± 5.6	0.10	0.17
Charlson Comorbidity Index	0.73 ± 1.4	0.20	0.005 ^{^b}

	N (%)^{^c}	LOS, median ± IQR
Sex
Male	139 (70.9)	6.9 ± 7.1	0.23
Female	57 (29.1)	6.7 ± 7.1	0.23
Insurance
Medicaid	45 (23.0)	7.6 ± 11.0	0.71
Medicare	40 (20.4)	7.0 ± 6.9
Private	79 (40.3)	6.6 ± 5.1
No insurance/self-pay	15 (7.7)	5.6 ± 12.4
Other	17 (8.7)	6.5 ± 6.1

↵a Continuous variables reported as mean ± SD and Spearman ρ correlation with LOS.
↵b Indicates statistically significant values with P < 0.05.
↵c Categorical variables reported as N (%) and median LOS ± IQR.
IQR, interquartile range; LOS, length of stay.

View popup

Table 2

Bivariate analysis of trauma variables and LOS.

Variable	Mean ± SD^{^a}	Spearman ρ	P Value^{^b}
Glasgow Coma Scale	13.9 ± 3.0	−0.38	<0.0001 ^{^b}
Injury severity score	20.5 ± 12.4	0.44	<0.0001^{^b}

	N (%)^{^c}	LOS, median ± IQR
Mechanism of injury			0.69
Fall	95 (48.5)	7.0 ± 6.6
Motor vehicle collision	91 (46.4)	6.6 ± 6.8
Ped struck	4 (2.0)	14.3 ± 28.1
Other	6 (3.1)	6.2 ± 4.1
Fracture level			<0.0001^{^b}
T1-T9	89 (45.4)	8.9 ± 13.1
T10-L2	90 (45.9)	6.0.± 3.1
L3-L5	17 (8.7)	6.0 ± 4.4
Fracture morphology			0.005^{^b}
Burst/compression	94 (48.5)	6.4 ± 4.0
Extension-distraction	16 (8.2)	6.4 ± 7.1
Flexion-distraction	29 (14.9)	6.0 ± 7.6
Fracture-dislocation	36 (18.6)	11.1 ± 12.8
Combination >1	19 (9.8)	7.3 ± 8.1
American Society of Anesthesiologists classification			<0.0001^{^b}
1	16 (9.1)	5.3 ± 5.8
2	73 (41.5)	5.8 ± 3.6
3	73 (41.5)	8.3 ± 6.4
4	14 (8.0)	25.3 ± 29.4
Loss of consciousness			0.0009^{^b}
No	142 (72.4)	6.1 ± 4.5
Yes	54 (27.6)	8.9 ± 16.7
Neurological status			<0.0001^{^b}
Intact	92 (48.2)	5.7 ± 4.61
Incomplete injury	59 (30.9)	6.6 ± 3.8
Complete injury	40 (20.9)	12.1 ± 20.6
Pulmonary injury			<0.0001^{^b}
No	129 (65.8)	5.9 ± 4.0
Yes	67 (34.2)	9.3 ± 12.6
Assisted ventilation			<0.0001^{^b}
No	169 (87.1)	6.4 ± 4.2
Mec. ventilation <96 h	13 (6.7)	9.9 ± 15.3
Mec. ventilation >96 h	12 (6.2)	21.8 ± 10.6
Polytrauma			<0.0001^{^b}
No	59 (30.1)	5.1 ± 3.1
Yes	137 (69.9)	7.6 ± 8.6

↵a Continuous variables reported as mean ± SD and Spearman ρ correlation with LOS.
↵b Indicates statistically significant values with P < 0.05.
↵c Categorical variables reported as N (%) and median LOS ± IQR.
IQR, interquartile range; LOS, length of stay.

View popup

Table 3

Bivariate analysis of perioperative variables and LOS.

Variable	Mean ± SD^{^a}	Spearman ρ	P Value^{^b}
Length of surgery	161.3 ± 90.5	0.32	<0.0001^{^b}
Instrumented segments	3.9 ± 1.5	0.30	<0.0001^{^b}
Estimated blood loss	582.8 ± 676.6	0.36	<0.0001^{^b}

	N (%)^{^c}	LOS, median ± IQR
Surgical technique			0.005^{^b}
Open	133 (67.9)	7.4 ± 7.1
Minimally invasive surgery	63 (32.1)	5.6 ± 4.2
Surgical approach			0.37
Posterior	184 (93.9)	6.7 ± 6.7
Anterior	9 (4.6)	6.5 ± 2.3
Combined	3 (1.5)	12.6 ± 5.3
Packed red blood cells transfusion			<0.0001^{^b}
No	144 (73.5)	6.0 ± 4.3
Yes	52 (26.5)	9.5 ± 11.2

↵a Continuous variables reported as mean ± SD and Spearman ρ correlation with LOS.
↵b Indicates statistically significant values with P < 0.05.
↵c Categorical variables reported as N (%) and median LOS ± IQR.
IQR, interquartile range; LOS, length of stay.

View popup

Table 4

Bivariate analysis of postoperative and postdischarge variables and LOS.

Variable	Mean ± SD^{^a}	Spearman ρ	P Value^{^b}
Number of unique complications^{^c}	2.5 ± 3.1	0.67	<0.0001^{^b}

	N (%)^{^d}	LOS, median ± IQR
Cardiac			0.002^{^b}
No	176 (89.8)	6.7 ± 5.5
Yes	20 (10.2)	14.4 ± 27.1
Pulmonary			<0.0001^{^b}
No	70 (35.7)	5.8 ± 3.1
Yes	126 (64.3)	13.0 ± 15.9
Gastrointestinal			<0.0001^{^b}
No	154 (78.6)	6.0 ± 3.3
Yes	42 (21.4)	16.2 ± 18.4
Renal/genitourinary			<0.0001^{^b}
No	137 (69.9)	6.0 ± 4.2
Yes	59 (30.1)	11.3 ± 11.1
Skin			0.001^{^b}
No	189 (96.4)	6.7 ± 6.2
Yes	7 (3.6)	23.6 ± 37.3
Neurologic			0.0001^{^b}
No	174 (88.8)	6.6 ± 5.0
Yes	22 (11.2)	13.4 ± 20.5
Hematologic/infectious			<0.0001^{^b}
No	124 (63.3)	6.0 ± 4.4
Yes	72 (36.7)	8.9 ± 12.8
Discharge facility			<0.0001^{^b}
Home	60 (31.1)	5.0 ± 2.0
Rehabilitation	131 (67.9)	8.5 ± 9.9
Other	2 (1.0)	3.1 ± 0.9
30-day readmission			0.51
No	190 (96.9)	6.8 ± 6.7
Yes	6 (3.1)	6.3 ± 5.6
Reoperation			0.93
No	193 (98.5)	6.8 ± 6.7
Yes	3 (1.5)	6.7 ± 7.4

↵a Continuous variables reported as mean ± SD and Spearman ρ correlation with LOS.
↵b Indicates statistically significant values with P < 0.05.
↵c See Appendix A for list of complications tracked.
↵d Categorical variables reported as N (%) and median LOS ± IQR.
IQR, interquartile range; LOS, length of stay.

View popup

Table 5

Multivariate analysis of ln-transformed LOS.

Formula:
	Estimate	Value^{^a}	P Value	Adjusted r ^{^b}
Model 1: preoperative variables only^{^c}				0.52
Intercept	2.30	-
GCS	0.52	GCS ≥11: −1 GCS <11: 1	<0.0001^{^d}
ASA	0.17	“1” or “2”: −1 “3” or “4”: 1	0.0003^{^d}
Neurological status	0.14	“Complete injury”: 1 Other: −1	0.03^{^d}
Polytrauma	0.12	No: −1 Yes: 1	0.03^{^d}
ISS	0.012	ISS	0.01^{^d}
Model 2: all variables^{^b}				0.69
Intercept	2.27	-
GCS	0.31	GCS ≥11: −1 GCS <11: 1	<0.0001^{^d}
ASA	0.096	“1” or “2”: −1 “3” or “4”: 1	0.007^{^d}
Neurological status	0.12	“Complete injury”: 1 Other: −1	0.008^{^d}
Polytrauma	0.16	No: −1 Yes: 1	<0.0001^{^d}
PRBC transfusion	0.085	No: −1 Yes: 1	0.03^{^d}
Number of unique complications	0.093	Number of unique complications	<0.0001^{^d}
Skin complication	0.20	No: −1 Yes: 1	0.03^{^d}
Discharge facility	0.11	Rehablitation center: 1 Other: −1	0.004^{^d}

↵a Use bolded value as value.
↵b All variables with statistically significant association with LOS included in initial model before backward stepwise selection: all statistically significant preoperative variables, length of surgery, instrumented segments, estimated blood loss, surgical technique, PRBC transfusion, number of unique complications, cardiac complications, pulmonary complications, gastrointestinal complications, renal/genitourinary complications, skin complications, neurologic complications, hematologic/infectious complications, and discharge facility.
↵c Preoperative variables with statistically significant association with LOS included in initial model before backward stepwise selection: Charles Comorbidity Index, GCS, ISS, fracture level, fracture morphology, ASA score, loss of consciousness, neurological status, pulmonary injury, assisted ventilation, and polytrauma.
↵d Indicates statistically significant values with P < 0.05.
ASA, American Society of Anesthesiologists; Estimate, regression coefficient; GCS, Glasgow Coma Scale; ISS, injury severity score; LOS, length of stay; PRBC, packed red blood cells.

Appendix A: Postoperative Complications Recorded by System

Cardiac: Cardiac catheterization, arrhythmia, hypotension/hypertension, pericarditis, syncope, and cardiogenic shock
Pulmonary: Lung abscess, pulmonary embolism, pleural effusion, pneumonia, reintubation, respiratory distress/failure, tracheostomy, atelectasis, pulmonary edema, pneumothorax, sinusitis, and empyema
Gastrointestinal: Clostridium difficile infection, constipation, dysphagia, gastrointestinal bleed, Ogilvie syndrome, pancreatitis, parenteral nutrition, percutaneous endoscopic gastrostomy, ileus, diarrhea, and acute cholecystitis
Renal/Gastrourinary: Acute renal failure, urinary retention, urosepsis, and urinary tract infectionSkin: Amputation, compartment syndrome, wound dehiscence, wound drainage, wound infection superficial, wound infection deep, and cellulitis
Neurologic: Delirium tremens, seizures, tardive dyskinesia, delirium, alcoholic withdrawal, diabetes insipidus, increased intracranial pressure, transient ischemic attack, and cerebral spinal fluid leak
Hematologic/Infectious: Septic shock, anemia, transfusion of blood products, bacteremia, deep vein thrombosis, hematoma, superficial thrombophlebitis, and coagulopathyOther (not included in a system): Fever >103 °F, acidosis, fluid and electrolytes, and nutrition