Computed Tomography Imaging Assessment of the Effect of Vancomycin Paste on Poststernotomy Healing

Figures & data

Figure 1 Flow chart of the study.

Table 1 Parameters of 6-Point Scale to Evaluate Sternal Bone Healing

Score	Definition	Description
0	No signs of healing (non-union)	No contact between sternal halves, absence of gap mineralization, and sclerotic osteotomy margins similar to that of cortical bone
1	Indeterminate	No contact or mineralization between the sternal halves, but osteotomy margins were nonsclerotic, concave, or irregular
2	Signs suggesting minimal or early healing	Faint mineralization between non-contacting sternal halves, a thin (1 mm) bridge of bone connecting the sternal halves anteriorly or posteriorly, or near bone-on-bone contact between the sternal halves, with sclerotic osteotomy margins
3	Mild synthesis	Bridging bone (i.e., no perceptible gap) along with less than 50% of the anteroposterior dimension of the sternal halves, with the sternal halves either offset in the anteroposterior dimension or aligned in the anteroposterior dimension
4	Moderate synthesis	Bridging bone (i.e., no perceptible gap) along 50% or more of the anteroposterior dimension of the sternal halves, with the sternal halves either offset in the anteroposterior dimension or aligned in the anteroposterior dimension, with visible remnants of the previous osteotomy
5	Complete synthesis	Sternal halves were well-aligned, and the appearance was that of essentially normal bone, without a gap or visible osteotomy margin

Notes: Adapted from: Stacy GS, Ahmed O, Richardson A, Hatcher BM, MacMahon H, Raman J. Evaluation of sternal bone healing with computed tomography and a quantitative scoring algorithm. Open Med Imaging J 2014;8;29–35. doi:10.2174/1874347101408010029.¹⁰ © Stacy et al; Licensee Bentham Open. Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/bync/3.0/).

Table 2 Sternal Levels Used for Assessment of Sternal Bone Healing by 6-Point Scale

Level	Description
Level 1	Manubrium at the first sternocostal articulation, using the first slice that does not show the clavicles (scrolling from cranial to caudal)
Level 2	Upper end of sternal body, using first slice below the second costal cartilage that does not show the sternomanubrial junction (scrolling from cranial to caudal)
Level 3	Mid-upper sternal body, using the slice through the lowest margin of the third costal cartilage
Level 4	Mid-lower sternal body, using the slice through the lowest margin of the fourth costal cartilage
Level 5	Lower end of sternal body, using the first slice at the level of the fifth costal cartilage that does not show the xiphoid process or xiphoid-body junction (scrolling from caudal to cranial)

Notes: Adapted from: Stacy GS, Ahmed O, Richardson A, Hatcher BM, MacMahon H, Raman J. Evaluation of sternal bone healing with computed tomography and a quantitative scoring algorithm. Open Med Imaging J 2014;8;29–35. doi: 10.2174/1874347101408010029.¹⁰ Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/bync/3.0/).

Table 3 General Characteristics of the Studied Patients

Variables	Vancomycin Group (n= 61)	Bone Wax Group (n= 61)	P-value
Age, years	57.3 ± 5.5 (45–67)	58 ± 5.1 (48–67)	0.15
Sex, n (%)			0.84
Male	45 (73.8)	46 (75.4)
Female	16 (26.2)	15 (24.6)
Risk factors
BMI	35.8 ± 2.5 (30.2–39)	35.2 ± 2.2 (30.1–38)	0.24
HbA1C	7.8 ± 0.5 (7–8.6)	7.9 ± 0.5 (7.2–8.5)	0.27
COPD, n (%)	10 (16.4)	9 (14.8)	0.80

Notes: Unless otherwise indicated, data represent the mean ± SD and range in parenthesis.

Abbreviations: SD, standard deviation; BMI, body mass index; HBA1C, haemoglobin A1C; COPD, chronic obstructive pulmonary disease.

Table 4 Perioperative Data in the Two Groups

	Vancomycin Group (n= 61)	Bone Wax Group (n= 61)	P-value
Ischemic time (minutes)	56.6 ± 14.3 (20–80)	59.7 ± 14.7 (20–90)	0.25
CBP time (minutes)	94.1 ± 24.7 (45–150)	100.7 ± 27.3 (45–160)	0.16
Number of grafts	2.9 ± 0.6 (1–4)	3 ± 0.7 (1–4)	0.89
Total operation time (minutes)	190 ± 34.7 (135–300)	205 ± 39.1 (135–300)	0.16
IABP use, n (%)	1 (1.6)	1 (1.6)	1.0
Re-exploration for bleeding, n (%)	5 (8.2)	4 (6.6)	0.52
Mechanical ventilation period\ hours	7 ± 9.4 (3–72)	6.2 ± 5.4 (3–36)	0.82
Blood transfusion units (Packed RBCs)	2.9 ± 1.3 (1–8)	2.8 ± 1.3 (1–8)	0.68
Total tube drainage/mL	418.9 ± 263.97 (200–1500)	412.4 ± 224.8 (200–1200)	0.77
Vasopressor duration (days)	1.3 ± 0.7 (1–5)	1.2 ± 0.5 (1–3)	0.61
Postoperative ICU stay (days)	2.5 ± 1 (2–7)	2.3 ± 0.7 (2–4)	0.47
Total hospitalization period	11 ± 3.6 (8–26)	10.3 ± 2.3 (8–18)	0.23

Notes: Unless otherwise indicated, data represent the main ± standard deviation and range in parenthesis.

Abbreviations: CBP, cardiopulmonary bypass time; IABP, Intra-Aortic Balloon Pump; RBCs, red blood cells; ICU, intensive care unit.

Figure 2 Bar chart shows the poststernotomy wound infection in both groups.

Table 5 Assignment of 6-Point CT Score for Sternal Healing in the Two Groups Stratified by Readers

Score	Vancomycin Group (n = 61)			Bone Wax Group (n = 61)
	Reader 1	Reader 2	Consensus	Reader 1	Reader 2	Consensus
0	1 (1.6)	0	0	2 (3.3)	1 (1.6)	0
1	0	2 (3.3)	0	3 (4.9)	1 (1.6)	0
2	2 (3.3)	1 (1.6)	0	13 (21.3)	12 (19.7)	12 (19.7)
3	4 (6.6)	8 (13.1)	6 (9.8)	19 (31.2)	17 (27.8)	17 (27.8)
4	52 (85.2)	48 (78.7)	53 (86.9)	24 (39.3)	30 (49.1)	32 (52.5)
5	2 (3.3)	2 (3.3)	2 (3.3)	0	0	0
Mean ±SD (range)	3.8±0.7 (0–5)	3.8±0.7 (1–5)	3.9±0.4 (3–5)	3±1.1 (0–4)	3.2±0.9 (0–4)	3.3±0.8 (2–4)

Notes: Unless otherwise indicated, data represent the number of patients and percentage in parenthesis.

Abbreviation: SD, standard deviation.

Table 6 Relation Between the Occurrence of Infection and 6-Point CT Score for Sternal Healing Among Patients of the Two Groups

	CT Score for Sternal Healing		P-value
	Infected Patient	Non-Infected Patient
Vancomycin group	4 ± 0.6 (3–5)	3.9 ± 0.3 (3–5)	0.79
Bone wax group	3.2 ± 0.6 (2–4)	3.8 ± 0.5 (3–4)	0.003

Notes: Data represent the main ± standard deviation and range in parenthesis.

Figure 3 A 60-year-old-diabetic-male patient with sternotomy and received local sternal vancomycin paste. (A) Axial (bone window) images at the five fixed anatomic levels show the sternal halves are well-aligned. The appearance is that of essentially normal bone without gap or obvious osteotomy margin at all five levels. The mean 6-point CT score of sternal healing is 5, denoting complete healing. (B and C) A reformatted 3D image confirms the complete healing.

Figure 4 A 62-year-old-diabetic-male patient with sternotomy and received bone wax on the divided edge of the sternum. (A) Axial (bone window) images at the five fixed anatomic levels show level 1, partial synthesis (significant bridging bone) (score 4). Level 2, no sign of healing (sternal separation, non-union, clear lack of healing) (score 0). Level 3, minimal healing (lack of bridging bone, sternal separation) (score 1). Level 4, moderate healing (partial bridging bone) (score 3). Level 5, complete synthesis (complete bridging bone) (score 5). The mean CT score of sternal healing is 2.6, denoting incomplete healing. (B and C) A reformatted 3D image confirms the incomplete healing.

Stacy GS, Ahmed O, Richardson A, Hatcher BM, MacMahon H, Raman J. Evaluation of sternal bone healing with computed tomography and a quantitative scoring algorithm. Open Med Imaging J. 2014;8:29–35. doi:10.2174/1874347101408010029

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