Radiofrequency ablation of atypical cartilaginous tumors in long bones: a retrospective study

Figures & data

Figure 1. CONSORT diagram showing the inclusion and exclusion criteria and the resulting eligible patients, who were separated into two groups based on the length of the electrode used to treat them.

Table 1. Patients, parameters, and outcomes.

Patient	Age	Bone	Location	Electrode length (mm)	Time at 90° C (mins)	Time > 60° C (mins)	Tumor, perpendicular diameter	Tumor, longitudinal diameter	Ablation, perpendicular diameter	Ablation, longitudinal diameter
1	24	Femur	Diaphysis	20.00	6	8	18	38	19	42
2	39	Femur	Metaphysis	20.00	10	12	16	18	24	42
3	54	Humerus	Diaphysis	20.00	8	8	12	18	14	33
4	64	Humerus	Metaphysis	30.00	6	12	21	29	32	42
5	26	Femur	Metaphysis	30.00	10	8	19	25	27	43
6	49	Tibia	Metaphysis	20.00	6	8	17	20	43	44
7	48	Femur	Metaphysis	30.00	8	10	23	32	41	63
8	69	Femur	Metaphysis	30.00	6	10	15	26	28	48
9	56	Tibia	Metaphysis	20.00	9	10	14	23	40	43
10	52	Femur	Metaphysis	20.00	9	9	23	25	43	51
11	72	Femur	Metaphysis	30.00	8	10	22	26	37	46
12	44	Femur	Metaphysis	20.00	7	9	10	12	17	33
13	29	Femur	Metaphysis	30.00	6	8	16	23	33	43
14	43	Femur	Metaphysis	20.00	6	8	17	20	39	43
15	41	Femur	Metaphysis	20.00	9	10	13	16	24	30
16	72	Femur	Metaphysis	20.00	7	8	19	25	25	39

Table 2. Summary of the patients and ablations parameters.

Patients	16
Age	48.8 (±15.3) years
Bone (femur/tibia/humerus)	12/2/2
Location (diaphysis/metaphysis)	2/14
Patients per needle length (20/30)	10/6
Time > 60 °C	9.25(±1.3 , range 8–12) min
Time at 90 °C	7.56 (±1.5, range 6–10) min

Figure 2. (A, B) intraoperative CT and postoperative gadolinium-enhanced MR of a tumor ablated close to the cortical wall in a femur metaphysis. (C, D) intraoperative CT and postoperative gadolinium-enhanced MR images of a centrally located tumor ablated in a femur metaphysis.

Table 3. Longitudinal and perpendicular diameters of the tumors and ablations. All measurements are in millimeters. Values with a * are normally distributed and represent thus the mean and standard deviation (SD), whereas the rest are non-normally distributed and represent the median and interquartile ranges (IQR), as indicated.

		All patients (n = 16)			20 mm electrode (n = 10)			30 mm electrode (n = 6)
		Mean/median	SD/IQR	Range	Mean/median	SD/IQR	Range	Mean/median	SD/IQR	Range
Resulting ablations	longitudinal axis	43	5	30–63	42	8.5	30–51	44.5	4.5	42–63
	perpendicular axis	28	15	14–43	24.5	19.5	14–43	32.5	7	27–41
Treated tumors	longitudinal axis	23.5*	6.3*	12–38	20	6.5	12–38	26	3	23–32
	perpendicular axis	17.1*	3.8*	10–23	16.5	4.5	10–23	20	5	15–23

Figure 3. Tumor diameters versus resulting ablation diameters of all 16 patients. Left: longitudinal ablation and tumor diameters. Right: Perpendicular ablation and tumor diameters. The solid diagonal lines in the graphs represent the point where the size of the ablation and the tumor could be the same, indicating the potential risk of recurrence.

Table 4. Median, IQR, and range of the difference between the resulting ablation diameters and tumor diameters. All values are in millimeters.

Ablation diameters minus tumor diameters
	20 mm electrode (n = 10)		30 mm electrode (n = 6)
	Perpendicular	Longitudinal	Perpendicular	Longitudinal
Median	9.5	20.5	14	20
IQR	15.2	9.5	5.0	8.5
Range	1–26	4–26	8–18	13–31