Interventional Spine

Kunal I Nanavati, MD,
Kunal I Nanavati, MD, Non ASSR Member
M Judith Don Post, MD, ASSR Member
John David Pitcher, Jr, MD, Non ASSR Member

Scientific Poster

Exhibit Panels: 0

Mentor Award: No

Institution where work was conducted

University of Miami / Jackson Memorial Hosptial

Affiliation and Department

Jackson Memorial Hospital, Radiology Department

Address

1611 NW 12th Avenue
Rm 279
miami, Florida
33136
Phone: 786 547 0091
Email: knanavati@med.miami.edu

Purpose

Palliative thermal ablation for radiation resistant painful bone metastasis has become standard of care in past decade. Thermal injury to adjacent organ or viscera is the most common avoidable grave complication of this procedure (1,2 and 3). We describe different methods of avoiding thermal injury to adjacent organs like skin and bowel during thermal ablation of sacral mass.

These image guided techniques can be broadly divided into two types based on their working principle:

Principle I: Safe distance

Distance of one centimeter from the margin of the ablation is considered to be a safe distance to avoid injury (4,5 and 6). Safety of the adjacent organ is highly questionable.
Following different techniques can be employed to create safe distance between the ablation zone and the adjacent organ.

a) Patient position: change in position of patient to achieve displacement of the mobile organ. This technique is mainly applied in renal ablations, to displace distended bowel, but can be helpful elsewhere in certain scenarios(7).

b) Organ position: change in position of adjacent mobile organ
Under close monitoring can create safe distance e.g. Rectum and sigmoid colon can be kept at a safe distance by good bowel preparation and if needed a flatus tube can be placed to keep it deflated.

c) Dissection: technique to create and maintain safe distance by means of introduction of gas, liquid or other inert material (e.g. balloon). This is the most commonly employed technique to avoid injury (4 and 8).

Principle II: Thermal Counter Protection
.
It is the prevention of organ injury by application of counter thermal energy to maintain the temperature of the adjacent normal organ within viable range and avoid injury. e.g. application of controlled heat during cryoablation and vice-versa during radiofrequency ablation to adjacent organ in danger. It is mainly used to prevent skin damage (8).

In summary, every interventionist should be aware of different techniques available to avoid potential complications. Understanding of above described different techniques with their basic working principle can simplify the procedure and will increase the confidence of the operator and decrease the complication rate for these palliative procedures.

References

1) Radiology 2003;226:441-451; Treatment of Focal Liver Tumors with
Percutaneous Radio-frequency Ablation: Complications
Encountered in a Multicenter Study; Tito Livraghi, MD, Luigi
Solbiati, MD, M. Franca Meloni, MD, G. Scott Gazelle, MD, PhD,
MPH, Elkan F. Halpern, PhD and S. Nahum Goldberg, MD
2) Br J Surg 2002; 89:1206-1222. Complications of radiofrequency
coagulation of liver tumors. Mulier S, Mulier P, Ni Y, et al.
3) AJR 2003; 181: 695-700. Adverse events during the radiofrequency
treatment of 582 hepatic tumors. De Baere T, Risse O, Kuoch V, et
al.
4) JVIR 2006; 17: 1545-1547; Subdermal Fluid for skin protection
during superficial palliative thermal ablation. Sudheendra D, Dromi
S, Wood B, et al.
5) JVIR 2004; 15:865-867; Cutaneous thermal injury after endovenous
laser ablation of the great saphenous vein. Sichlau MJ, Rye RK.
6) Am Surg 2003; 69(1):37-40; Radiofrequency ablation of breast
cancer. Singletary SE
7) Urology 2002; 60:954-958; Percutaneous radiofrequency ablation
of renal tumors: technique, limitations and morbidity. Ogan K,
Jacomides L, Dolmatch BL, et al.
8) AJR 2004; 182:1459-1461; Thermal Protection during
radiofrequency ablation; Robert P. Liddell and Stephen B Solomon
Images:
Image 1: An example of safe distance: Mini stick needle seen in pool of saline created in between the rectal air(arrow) and sacral tumor to establish safe distance.
Image 2. An example of counter protection: Perc 17 cryoprobe in sacral tumor with hypodense ice surrounding it (arrow). Hot water filled glove directly applied over the skin above the tumor can be seen. Ice ball is not involving the skin and flattens due to counter effect of heat provided by hot water filled glove.

Images