Search Results

You are looking at 1 - 5 of 5 items for

  • Author or Editor: Athan G. Zavras x
  • Refine by Access: all x
Clear All Modify Search
Free access

Longitudinal assessment of segmental motion of the cervical spine following total disc arthroplasty: a comparative analysis of devices

Matthew W. Colman, Athan G. Zavras, Vincent P. Federico, Michael T. Nolte, Alexander J. Butler, Kern Singh, and Frank M. Phillips

OBJECTIVE

Total disc arthroplasty (TDA) has been shown to be an effective and safe treatment for cervical degenerative disc disease at short- and midterm follow-up. However, there remains a paucity of literature reporting the differences between individual prosthesis designs with regard to device performance. In this study, the authors evaluated the long-term maintenance of segmental range of motion (ROM) at the operative cervical level across a diverse range of TDA devices.

METHODS

In this study, the authors retrospectively evaluated all consecutive patients who underwent 1- or 2-level cervical TDA between 2005 and 2020 at a single institution. Patients with a minimum of 6 months of follow-up and lateral flexion/extension radiographs preoperatively, 2 months postoperatively, and at final follow-up were included. Radiographic measurements included static segmental lordosis, segmental range of motion (ROM) on flexion/extension, global cervical (C2–7) ROM on flexion/extension, and disc space height. The paired t-test was used to evaluate improvement in radiographic parameters. Subanalysis between devices was performed using one-way ANCOVA. Significance was determined at p < 0.05.

RESULTS

A total of 85 patients (100 discs) were included, with a mean patient age of 46.01 ± 8.82 years and follow-up of 43.56 ± 39.36 months. Implantations included 22 (22.00%) M6-C, 51 (51.00%) Mobi-C, 14 (14.00%) PCM, and 13 (13.00%) ProDisc-C devices. There were no differences in baseline radiographic parameters between groups. At 2 months postoperatively, PCM provided significantly less segmental lordosis (p = 0.037) and segmental ROM (p = 0.039). At final follow-up, segmental ROM with both the PCM and ProDisc-C devices was significantly less than that with the M6-C and Mobi-C devices (p = 0.015). From preoperatively to 2 months postoperatively, PCM implantation led to a significant loss of lordosis (p < 0.001) and segmental ROM (p = 0.005) relative to the other devices. Moreover, a significantly greater decline in segmental ROM from 2 months postoperatively to final follow-up was seen with ProDisc-C, while segmental ROM increased significantly over time with Mobi-C (p = 0.049).

CONCLUSIONS

Analysis by TDA device brand demonstrated that motion preservation differs depending on disc design. Certain devices, including M6-C and Mobi-C, improve ROM on flexion/extension from preoperatively to postoperatively and continue to increase slightly at final follow-up. On the other hand, devices such as PCM and ProDisc-C contributed to greater segmental stiffness, with a gradual decline in ROM seen with ProDisc-C. Further studies are needed to understand how much segmental ROM is ideal after TDA for preservation of physiological cervical kinematics.

Restricted access

Preoperative diagnosis of mental health disorder and dysphagia following anterior cervical spine surgery

Athan G. Zavras, Rajko S. Vucicevic, Vincent P. Federico, Michael T. Nolte, Nicholas A. Shepard, Arash J. Sayari, and Matthew W. Colman

OBJECTIVE

Mental health disorders (MHDs) have been linked to worse postoperative outcomes after various surgical procedures. Past studies have also demonstrated a higher prevalence of dysphagia in both acute and community mental health settings. Dysphagia is among the most common complications following anterior cervical spine surgery (ACSS); however, current literature describing the association between an established diagnosis of an MHD and the rate of dysphagia after ACSS is sparse.

METHODS

All patients who underwent ACSS between 2014 and 2020 with a minimum of 6 months of follow-up were retrospectively evaluated at a single institution. Patients were divided into cohorts depending on an established diagnosis of an MHD: the first had no established MHD (non-MHD); the second included patients with a diagnosed MHD. Outcomes were measured using pre- and postoperative patient-reported outcome scores, which included the Swallowing Quality of Life survey for dysphagia, as well as physical and mental health questionnaires. Postoperative dysphagia surveys were obtained at final follow-up for both patient cohorts.

RESULTS

A total of 68 and 124 patients with and without a diagnosis of a MHD were assessed. The MHD group reported significantly worse baseline Patient-Reported Outcomes Measurement Information System depression scale scores (p < 0.001), 12-Item Short-Form Health Survey (p < 0.001), and Veterans RAND 12-Item Health Survey (p = 0.001) mental health components compared to non-MHD group. This group continued to have worse mental health status in the postoperative period, as reported by Patient-Reported Outcomes Measurement Information System depression scale scores (p = 0.024), 12-Item Short-Form Health Survey (p = 0.019), and Veterans RAND 12-Item Health Survey (p = 0.027). Postoperative assessment of Swallowing Quality of Life scores (expressed as the mean ± SD) also showed worse dysphagia outcomes in the MHD cohort (80.1 ± 12.2) than in the non-MHD cohort (86.0 ± 12.1, p = 0.001).

CONCLUSIONS

ACSS is associated with significantly higher postoperative dysphagia in patients diagnosed with an MHD when compared to patients without an established mental health diagnosis. Given the high prevalence of MHDs in patients with spinal pathology, it is important for spine surgeons to take note of the increased incidence of dysphagia faced by this patient population.

Restricted access

Segmental range of motion after cervical total disc arthroplasty at long-term follow-up: a systematic review and meta-analysis

Athan G. Zavras, Navya Dandu, Michael T. Nolte, Alexander J. Butler, Vincent P. Federico, Arash J. Sayari, T. Barrett Sullivan, and Matthew W. Colman

OBJECTIVE

As an alternative procedure to anterior cervical discectomy and fusion, total disc arthroplasty (TDA) facilitates direct neural decompression and disc height restoration while also preserving cervical spine kinematics. To date, few studies have reported long-term functional outcomes after TDA. This paper reports the results of a systematic review and meta-analysis that investigated how segmental range of motion (ROM) at the operative level is maintained with long-term follow-up.

METHODS

PubMed and MEDLINE were queried for all published studies pertaining to cervical TDA. The methodology for screening adhered strictly to the PRISMA guidelines. All English-language prospective studies that reported ROM preoperatively, 1 year postoperatively, and/or at long-term follow-up of 5 years or more were included. A meta-analysis was performed using Cochran’s Q and I2 to test data for statistical heterogeneity, in which case a random-effects model was used. The mean differences (MDs) and associated 95% confidence intervals (CIs) were reported.

RESULTS

Of the 12 studies that met the inclusion criteria, 8 reported the long-term outcomes of 944 patients with an average (range) follow-up of 99.86 (60–142) months and were included in the meta-analysis. There was no difference between preoperative segmental ROM and segmental ROM at 1-year follow-up (MD 0.91°, 95% CI −1.25° to 3.07°, p = 0.410). After the exclusion of 1 study from the comparison between preoperative and 1-year ROM owing to significant statistical heterogeneity according to the sensitivity analysis, ROM significantly improved at 1 year postoperatively (MD 1.92°, 95% CI 1.04°–2.79°, p < 0.001). However, at longer-term follow-up, the authors again found no difference with preoperative segmental ROM, and no study was excluded on the basis of the results of further sensitivity analysis (MD −0.22°, 95% CI −1.69° to −1.23°, p = 0.760). In contrast, there was a significant decrease in ROM from 1 year postoperatively to final long-term follow-up (MD −0.77°, 95% CI −1.29° to −0.24°, p = 0.004).

CONCLUSIONS

Segmental ROM was found to initially improve beyond preoperative values for as long as 1 year postoperatively, but then ROM deteriorated back to values consistent with preoperative motion at long-term follow-up. Although additional studies with further longitudinal follow-up are needed, these findings further support the notion that cervical TDA may successfully maintain physiological spinal kinematics over the long term.

Free access

Does disc distraction after cervical total disc arthroplasty impact range of motion and patient-reported outcomes?

Vincent P. Federico, Athan G. Zavras, James W. Nie, Alexander J. Butler, Mohammed A. Munim, Michael T. Nolte, Gregory D. Lopez, Howard S. An, Matthew W. Colman, and Frank M. Phillips

OBJECTIVE

Total disc arthroplasty (TDA) has been established as a safe and effective alternative to anterior cervical discectomy and fusion for the treatment of cervical spine pathology. However, there remains a paucity of studies in the literature regarding the amount of disc height distraction that can be tolerated, as well as its impact on kinematic and clinical outcomes.

METHODS

Patients who underwent 1- or 2-level cervical TDA with a minimum follow-up of 1 year with lateral flexion/extension and patient-reported outcome measures (PROMs) were included. Middle disc space height was measured on preoperative and 6-week postoperative lateral radiographs to quantify the magnitude of disc space distraction, and patients were grouped into < 2-mm distraction and > 2-mm distraction groups. Radiographic outcomes included operative segment lordosis, segmental range of motion (ROM) on flexion/extension, cervical (C2–7) ROM on flexion/extension, and heterotopic ossification (HO). General health and disease-specific PROMs were compared at the preoperative, 6-week, and final postoperative time points. The independent-samples t-test and chi-square test were used to compare outcomes between groups, while multivariate linear regression was used to adjust for baseline differences.

RESULTS

Fifty patients who underwent cervical TDA at 59 levels were included in the analysis. Distraction < 2 mm was seen at 30 levels (50.85%), while distraction > 2 mm was observed at 29 levels (49.15%). Radiographically, after adjustment for baseline differences, C2–7 ROM was significantly greater in the patients who underwent TDA with < 2-mm disc space distraction at final follow-up (51.35° ± 13.76° vs 39.19° ± 10.52°, p = 0.002), with a trend toward significance in the early postoperative period. There were no significant postoperative differences in segmental lordosis, segmental ROM, or HO grades. After the authors controlled for baseline differences, < 2-mm distraction of the disc space led to significantly greater improvement in visual analog scale (VAS)–neck scores at 6 weeks (−3.68 ± 3.12 vs −2.24 ± 2.70, p = 0.031) and final follow-up (−4.59 ± 2.74 vs −1.70 ± 3.03, p = 0.008).

CONCLUSIONS

Patients with < 2-mm disc height difference had increased C2–7 ROM at final follow-up and significantly greater improvement in neck pain after controlling for baseline differences. Limiting differences in disc space height to < 2 mm affected C2–7 ROM but not segmental ROM, suggesting that less distraction may result in more harmonious kinematics between all cervical levels.

Restricted access

Comparison of clinical outcomes in patients undergoing one- and two-level minimally invasive lumbar microdiscectomy

Zakariah K. Siyaji, Austin Q. Nguyen, Vincent P. Federico, Shadi Zbeidi, Athan G. Zavras, James D. Baker, Bryce A. Basques, Arash J. Sayari, and Frank M. Phillips

OBJECTIVE

Herniated nucleus pulposus (HNP) is one of the most common lumbar spine conditions treated surgically, often through a minimally invasive surgery (MIS) microdiscectomy approach. This technique attempts to reduce damage to the paraspinal muscular-ligamentous envelope. However, there are currently limited data regarding comparative outcomes using patient-reported outcome measures (PROMs) for one- and two-level MIS discectomies. The aim of this study was to quantify comparative clinical outcomes in patients undergoing one-level and two-level MIS lumbar microdiscectomy for HNP using PROMs.

METHODS

The authors performed a retrospective review of patients undergoing MIS lumbar microdiscectomy between 2004 and 2019 for the primary diagnosis of HNP at a single academic institution. All patients had a minimum 1-year follow-up. Patient demographics and comorbidities were collected to establish baselines between cohorts. PROMs and minimal clinically important differences (MCIDs) were used to examine the patient’s perception of operative success. Bivariate and multivariate linear/logistic regression analyses were used to compare one- and two-level discectomies. The bivariate analysis included the t-test and chi-square test, which were used to assess continuous and categorical variables, respectively. Statistical significance was established at p < 0.05.

RESULTS

A total of 293 patients underwent one-level (n = 250) or two-level (n = 43) MIS discectomies. The mean follow-ups for the one- and two-level cohorts were 50.4 (SD 35.5) months and 61.6 (SD 39.8) months, respectively. Fewer female patients underwent two-level discectomies, and BMI and operative duration were higher in the two-level group (p < 0.001). Recurrent herniation requiring reoperation was recorded at rates of 6.80% and 11.6% in the one- and two-level groups, respectively (p = 0.270). Pre- and postoperative PROMs were largely similar between the cohorts; however, patients undergoing one-level discectomy had greater improvement in leg pain, and a significantly greater proportion of these patients achieved MCID for the leg pain visual analog scale score (p < 0.001).

CONCLUSIONS

At the 1-year clinical follow-up, patients who underwent two-level discectomy had significantly less improvement in leg pain scores with lower achievement of MCID for leg pain improvement than patients undergoing one-level procedures. At the 1-year follow-up, there were no other significant differences in PROMs between the two cohorts. Given these findings, patients should be counseled regarding the anticipated outcomes to better manage expectations. Further studies are warranted to examine the long-term clinical outcomes associated with single- and multilevel MIS discectomy.