NASS 2022: Robotic and navigational assistance is cost-effective for minimally-invasive adult spinal deformity surgery, new study shows

Peter Passias

Although robotic and navigational assistance systems have a significantly higher upfront cost compared to existing techniques, the findings of a new study—presented at the North American Spine Society’s (NASS) annual meeting (12–15 October, Chicago, USA) by Peter Passias (NYU Langone Health, New York, USA)—show that the reductions in intraoperative invasiveness and operating room (OR) time they offer, pay great dividends in demonstrating the two-year cost-effectiveness of such technology in minimally-invasive adult spinal deformity surgery.

The retrospective study, which was the recipient of a Value Award at NASS 2022, sought to assess differences in patient outcomes and relative cost effectiveness in L4-L5 spondylolisthesis patients treated using robotic or navigational guidance in minimally invasive spine surgery (MISS) procedures.

MISS patients with preoperative diagnoses of L4-L5 spondylolisthesis with baseline and two-year postoperative radiographic/HRQL data were included in the study and the key outcome measures were health-related quality of life, complications and surgical factors. Patients were split between those operated on using robotic or navigational guidance (Robotic+) or not (Robotic-).

Means comparison analysis assessed differences in radiographic and clinical outcomes at baseline, one year and two years postoperatively. Costs were calculated using the PearlDiver database through estimates from Medicare payscales for services within a 30-day window, including estimates regarding costs of postoperative complications, outpatient healthcare encounters, revisions and medical related readmissions.

Quality-adjusted life years (QALYs) was calculated using Neck Disability Index (NDI) mapped to the six-dimension health state short form (SF-6D) using validated methodology, and utilised a 3% discount rate to account for residual decline to life expectancy (78.7 years).

A total of 88 patients (54.40 ± 12.49 years, 40% female, 30.93 ± 6.52 kg/m2, mean Charlson Comorbidity Index [CCI]: 2.23 ± 1.55) with L4-5 spondylolisthesis were included. At baseline, patients were comparable in age, gender, body mass index and CCI (all p>0.05). Similarly, patients did not differ significantly in baseline regional nor global radiographic deformity (all p>0.05).

Perioperatively, the Robotic+ patients were shown to be significantly less likely to undergo corpectomy (p=0.006), and also demonstrated significantly lower estimated blood loss (p=0.013) and operative time (p=0.009).

Economic analysis revealed broad cost savings for Robotic+ patients. Specifically, Robotic+ patients demonstrated increased utility gained per QALYs at one year (p=0.028), as well as life expectancy QALYs (p=0.002). Furthermore, Robotic+ patients were significantly more likely to demonstrate increased QALYs gained by two years (p=0.029).

Conversely, overall cost per QALY by two years was significantly higher for Robotic- patients, which resulted in an approximately 6.5x greater cost per QALY for such patients (US$76,848 vs. US$11,839). Overall, Robotic+ patients demonstrated significantly higher cost-effectiveness by two years (p<0.001).

Speaking to Spinal News International, Passias said: “With robotic and navigational assistance in spine surgery becoming ever more prevalent, assessment of cost effectiveness of such tools is necessary. Especially in regards to corrective procedures for the treatment of L4-L5 spondylolisthesis, which is among the most common pathologies I treat; enhancement of our surgical arsenal in a cost-effective way may pave the way for improvement of patient-reported and surgical outcomes, and reduce costs for all parties involved.

“Of course, we acknowledge that robotic and navigational assistance systems have a significantly higher upfront cost compared to existing techniques, yet our findings demonstrate reductions in intraoperative invasiveness and OR time pay great dividends in cost-effectiveness of such novel technologies in minimally-invasive adult spinal deformity surgery. At minimum, we recommend that institutions and surgeons assess whether or not such technologies are right for them, as we recognise that cost of care remains an important domain within our field.”


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