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Treatment may progress faster after MIS for symptomatic metastatic spine disease
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SAN DIEGO — Outcomes from a minimally invasive approach used in patients with symptomatic metastatic spine disease compared well with those for patients who were treated with open surgery.
Patients treated with a minimally invasive surgery (MIS) technique typically lost less blood, and many could begin radiotherapy 11 days earlier than patients who underwent an open approach, according to Naresh Satyanarayan Kumar, MD, in the Department of Orthopaedic Surgery, National University Hospital, in Singapore.
“There is a place for MIS posterior pedicle screw fixation and decompression in tumor surgery. This is being established. Ours is probably one of the first few comparative studies between the two, using open pedicle screw technique or the MIS pedicle screw insertion technique for the treatment of metastatic spine disease. We see that MIS was slightly more expensive, however still affordable by patients in Singapore who pay for the implant costs. There were some cases where attempted MIS techniques were overridden by open technique in order to achieve appropriate surgical decompression,” Kumar said at the International Society for the Advancement of Spine Surgery Annual Meeting, here.
Open vs MIS
The study included 22 patients who underwent posterior surgery using MIS and 22 patients who underwent the same procedure via an open approach. All the patients were followed up for a minimum of 3 months from the time of surgery through the end of the study period (4 years) or their death, whichever was longer.
Naresh Satyanarayan Kumar
Kumar said most of the constructs were “two up and two down,” with a maximum of two decompressed levels per patient. All the patients reported having improvements in pain and neurological status. Significant VAS score improvement occurred in 17 patients in the MIS group and 12 patients in the open group.
Kumar told Spine Surgery Today the two glaring advantages of MIS approach were less intraoperative blood loss and shorter time to radiotherapy.
Kumar and colleagues found blood loss substantially increased with more levels of decompression and the more screws that were inserted. A multivariate analysis showed patients in the MIS cohort lost significantly less blood, at 537 mL less on average than patients in the open cohort.
Earlier initiation of radiotherapy
Patients in the MIS cohort also began to undergo radiotherapy 11 days sooner than patients in the open cohort. Although the length of hospital stay, operative time and time to initiate chemotherapy were more favorable in the MIS vs. the open cohort, these differences were not statistically significant.
Figure 1. This operative photo shows percutaneous pedicle screw fixation and decompression for metastatic disease.
Source: Kumar NS
“When you look at the morbidity and mortality in the patients, both were comparable in the two groups with no obvious statistical difference,” Kumar said.
Differences in Frankel scores
The researchers found better ambulatory rates in the MIS cohort, but noted this could possibly be due to their having better Frankel scores preoperatively. Posoperatively, about 82% of patients in the MIS cohort reached full normal function, which was a Frankel score of E in the MIS cohort, compared with 54% of patients in the open group. However, the difference in Frankel scores from preoperative with postoperative in the MIS cohort, according to a Kruskal-Wallis analysis done with the study, was statistically significant (P < .01).
About 88% of patients in the MIS cohort reached independent ambulation by 3 months postoperatively compared to 64% in the open group, but this was not a statistically significant difference.
The findings in this study may impact the way symptomatic metastatic spine disease is treated. MIS posterior pedicular screw fixation should be contemplated whenever possible, due to less perioperative morbidity and the ability to treat patients with radiotherapy earlier than an open surgical procedure, according to Kumar and colleagues. – by Robert Linnehan
- Reference:
- Kumar NS, et al. Paper #221. Presented at: International Society for the Advancement of Spine Surgery Annual Meeting; April 15-17, 2015; San Diego.
- For more information:
- Naresh Satyanarayan Kumar, MD, can be reached at 5 Lower Kent Ridge Rd., Singapore 119074; email: kumar_satyanarayan_naresh@nuhs.edu.sg.
Disclosure: Kumar reports no relevant financial disclosures.