High-frequency ultrasonic osteotomy in the treatment of intradural spinal tumors: matched cohort study

Posterior access in the form of (hemi-)laminectomy or laminoplasty is necessary for the treatment of intradural extramedullary tumors. Most frequently, this is carried out using high-speed burrs, rongeurs, and osteotomes. Recently, the principle of piezoelectrically generated high-frequency ultrasonic osteotomy (hfUSO) has become widely available, and promises several advantages including potentially reduced incidental durotomy, compression damage, and heat exchange.

We carry out a single-center cohort study comparing hfUSO-based laminoplasty vs. conventional laminectomy, and including all patients treated for spinal intradural extramedullary tumors using a posterior approach from 2005 to 2020. Patients with missing outcome data were excluded. Exact matching was used for spinal level (cervical, thoracic, and lumbosacral), number of segments operated, and tumor subtype, while age was matched with a ± 10-year tolerance. After matching, two-tailed intergroup comparisons were made. Clinical outcomes analyzed included procedural (operating time, estimated blood loss), perioperative (length of stay, readmission), and complication (reoperation, infection, hematoma, cerebrospinal fluid [CSF] leakage) data.

From 305 eligible patients, 104 had been treated using hfUSO. Accordingly, another 104 patients treated without the use of hfUSO were matched. The two groups (hfUSO vs. conventional) appeared well-matched for baseline data. With hfUSO, operating time was reduced (147 vs. 181 min, p = 0.009) as was length of hospital stay (3 vs. 5 days, p = 0.009). Estimated blood loss was comparable among groups (150 vs. 200 mL, p = 0.137). Overall, there was no change in rate of complications, reoperations, and readmissions (all p > 0.05).

When applied to posterior access, use of hfUSO-based laminoplasty demonstrated its effectiveness and safety, achieving comparable if not slightly superior clinical endpoints when contrasting with conventional laminectomy using high-speed burrs, rongeurs, and osteotomes. Apart from potential ergonomic benefits, the hfUSO technique was associated with relevantly decreased operating time (even with the added laminoplasty step) and length of stay as well as a comparably low blood loss, without increased device-related or overall complications.