The indication for gamma probe-guided surgery of spinal osteoid osteomas

Abstract

The standard treatment for osteoid osteomas is CT-guided radiofrequency ablation (RFA). This minimally invasive procedure is effective in terms of pain reduction as well as the recurrence rate. Nevertheless, the use for spinal lesions is limited due to a possible thermal damage of neural structures. Although the literature is contradictory, RFA should only be used when a cortical shell between the lesion and the spinal canal is existent. We present seven cases (five males, two females, mean age 23 years) with spinal osteoid osteoma in which RFA was not applicable and open resection with the use of probe-guided surgery (PGS) was performed. The principle of PGS is that after preoperative bone scintigraphy, a handheld radiation probe is used intraoperatively for tumour localisation. Here, exposure and bone resection can be minimised and completeness of tumour excision may be estimated. At the initial measurement we found a hot-spot (maximum countrate) in all patients and after tumour resection, the signal decreased by a mean of 68% in the operative field. After a mean follow-up of 17 months one patient had residual pain but no patient had signs of tumour recurrence. The authors recommend to use PGS for those spinal osteoid osteomas where RFA is not applicable and intraoperative localisation-and here complete resection-of the tumour is difficult.

Follow-up bone scintigraphy images of a patient with osteoid osteoma during medical treatment

“…The main goal of the surgical methods is excision of the nidus with minimal damage to adjacent tissues 12. Because of this, CT-guided or γ-probe-guided surgical interventions are preferred 13. Preoperative CT or bone scintigraphy together with γ-probe in surgery correctly localises and guides surgery.…”

Thermal Ablation of Spinal Osteoid Osteomas Close to Neural Elements: Technical Considerations

“…Our results show that thermal ablation can be used effectively and safely to manage osteoid osteomas of the spine even when the lesion is within 1 cm of the adjacent neural elements or lacks a complete intervening rim of cortical bone. In the past, these techniques were avoided in the treatment of patients with spinal lesions because of the risk of thermal damage to the neural elements [9,[11][12][13]. Some authors have proposed alternative minimally invasive imaging-guided methods, including percutaneous trocar extraction and alcohol injection.…”

“…. Surgical complications specific to the spine include incomplete removal, instability secondary to resection of the posterior elements, and cord or nerve injury [6,9,10].…”

“…For years, lesions within the spine were considered untreatable with radiofrequency ablation (RFA) because of the inherent risk posed by proximity to the neural elements [9,[11][12][13]. Both in vivo and ex vivo experiments on the generation of heat in the spinal canal and perineural tissues during ablation have been conducted on animal models, and the influences of proximity to neural structures, the presence of intervening bone, and probe size have been evaluated [14][15][16][17].…”

Thermometry during coblation and radiofrequency ablation of vertebral metastases: a cadaver study

“…In general, there are two different thermal ablation methods: radiofrequency ablation (RFA) and radiofrequency ionization (coblation). RFA is a well-known technique, which is also used in the treatment of primary tumors like renal cell carcinoma [4], hepatocellular carcinoma [5] or osteoid osteoma [6]. There are two different types of RFA applicators: monopolar and bipolar systems.…”