20. Single-stage debridement and reconstruction with trabecular metal cage for active infectious spondylodiscitis: a retrospective cohort study

Abstract

BACKGROUND CONTEXT

Early debridement and stabilization for pyogenic spondylodiscitis allow early mobilization of the patient and prevent subsequent spinal deformity. Tantalum (Ta) trabecular metal (TM) components have several potential advantages over conventional implant materials, such as its uniformity and structural continuity, strength, low stiffness, high porosity, and high coefficient of friction. Tantalum trabecular metal also enhances the host defense mechanism by increasing leukocyte chemotaxis, phagocytosis, and the bacterial killing rate. A single-stage surgery with a tantalum trabecular metal cage combining two different approaches is sufficient to maintain vertebral stability.

PURPOSE

To evaluate the efficacy and benefits of tantalum metal cages for patients with spondylodiscitis, it is advisable to perform single-stage debridement and reconstruction with a trabecular metal cage, which allows abscess drainage and rapid mobilization, prevents deformity.

STUDY DESIGN/SETTING

A single-stage surgery with a tantalum trabecular metal cage combining two different approaches is sufficient to maintain vertebral stability. This retrospective cohort study included 57 patients. Of these, 31 (54%) patients were treated with single-stage debridement and reconstruction with trabecular metal cages, and 26 (45.6%) patients received spine surgery without trabecular metal cages received surgery between January 2018 and March 2021 at our tertiary academic teaching hospital.

PATIENT SAMPLE

This was a retrospective study of spondylodiscitis patients who underwent surgery between January 2018 and March 2021 in our tertiary academic teaching hospital. We examined clinical records, radiological images, and surgical notes acquired for all patients who underwent surgical procedures for spondylodiscitis with vertebral body lysis and a propensity for deformity in our institution. Fifty-seven patients met the inclusion criteria (35 male, 22 female). The mean age at the time of treatment was 67 ± 14.08 years (range, 25–92 years). Thirty-one patients underwent reconstructive surgery with a tantalum trabecular metal cage [ZimmerR]. For comparison, we also included 26 patients who underwent surgery without tantalum trabecular metal cages in the same period.

OUTCOME MEASURES

We examined patient demographic data, including age and sex, as well as symptoms, laboratory results, neurological examination, radiographic images, operative reports, postoperative complications, and data from clinical and radiological follow-up. We evaluated the CRP data during therapy.

METHODS

In all patients, blood tests for CRP levels were obtained 3 days before surgery as baseline data. Further blood chemistry controls in all patients were performed after surgery. As blood tests were not performed on the same day for all patients, we assessed values on Days 0-3, 4-7, 8-14, 15-21, and 22-28 to obtain comparable results. Regarding CRP data, the spread of metric variables among independent groups was described using the Shapiro-Wilk test, evaluating whether the random sample survey exhibited a normal distribution. If the assumption of normal distribution was not rejected (p value = 0.1), a t-test was employed for comparisons. In cases where the assumption of normal distribution was rejected, the Mann-Whitney U test was utilized. Fisher’s exact test was applied to examine the relationship between two categorical variables. Given the exploratory nature of this study, all p values are reported descriptively.

RESULTS

Out of 57 patients, 31 (54%) patients were treated with single-stage debridement and reconstruction with trabecular metal cages, and 26 (45.6%) patients received spine surgery without trabecular metal cages. In the TM cage group, the mean age was 68 years (range, 25–92 years), and there were 18 male and 13 female patients. In the non-TM cage group, the mean age was 65 years (range, 41-85 years). The mean age and age range of the TM group were older and wider than those of the non-TM cage group. The percentage of the spine location was similar between the two groups. The level of CRP data was lower in the TM cage group at three different times (before surgery, postoperation Days 0-3, postoperation Days 22-28). The periods of inpatient stay after the operation were shorter in the Non-TM cage group (TM cage group vs Non-Tm cage group: 47 vs 41 days). A second intervention for debridement, interbody fusion, vertebral body replacement, cage or screw removal was performed in 11 (19.3%) cases within one month after the first intervention. A second intervention was performed significantly more frequently in the non-TM cage group (34.6% vs 6.5%; P= 0.0155) 3 months after the first surgery. The kyphotic angle correction was similar between the two groups, and the correction angle of the TM cage group was slightly smaller than that of the non-TM cage group (-6.27° vs -6.35°; P=0.7595; in our study definition, kyphosis was positive). There was no obvious statistical significance between the two groups. There was no revision surgery for implant failure in either group.

CONCLUSIONS

Early debridement and stabilization allow early mobilization of the patient and prevent subsequent spinal deformity. A single-stage surgical procedure that integrates two distinct approaches is capable of preserving vertebral stability. In cases of spondylodiscitis characterized by osteolysis and instability, it is recommended to opt for a single-stage approach involving debridement and reconstruction using a trabecular metal cage. This approach facilitates abscess drainage, enables swift mobilization, mitigates the risk of deformity, and minimally interferes with the effectiveness of antibiotic treatment.

FDA Device/Drug Status

“Zimmer TMT” TM Ardis Interbody System Solid (Approved for this indication).