Two- versus multi-rod constructs for adult spinal deformity: A systematic review and Random-effects and Bayesian meta-analysis

Single-Photon Emission Computed Tomography (SPECT-CT) as a Predictor of Pain Generators in Patients Undergoing Anterior Cervical Discectomy and Fusion (ACDF) for Axial Cervical Pain

BACKGROUND

Axial neck pain is often associated with cervical instability, and surgical options are often reserved for patients with either neurological compromise or deformity of the spine. However, cervical facet arthropathy is often implicated with instability and the location of painful generators is often difficult to ascertain. Single-photon emission computed tomography (SPECT-CT) presents an adjunct to conventional imaging in the workup of patients with suspected facetogenic pain. We aimed to report our experience with patients undergoing anterior cervical discectomy and fusion (ACDF) guided by SPECT-CT for axial cervical pain.

METHODS

We retrospectively identified all cases undergoing ACDF that presented with axial neck pain where correlating SPECT-CT high metabolism areas were identified. Patients were treated at a tertiary care institution between January 2018 and January 2021. Patients with positive radiotracer uptake pre-operatively were compared with patients undergoing ACDF without uptake on SPECT-CT. The pre- and post-operative patients who reported neck pain at one year were compared.

RESULTS

Thirty-five patients were included in this retrospective cohort. The median pre- and post-intervention (at one-year follow-up) visual analog score (VAS) of patients undergoing ACDF without uptake on SPECT-CT was 7 and 3 (p<0.01), while the pre- and post-VAS for patients undergoing surgery with positive uptake on SPECT-CT was 8.5 and 0 (p<0.01). Improvement was significantly larger for patients undergoing SPECT-CT-guided ACDF (p=0.02). At one year after surgery, none of the assessed patients required additional surgical intervention.

CONCLUSION

This case series represents the experience of our group to date with patients undergoing SPECT-CT-guided ACDF with results suggesting potential benefit in guiding fusion.

T1 Pedicle Subtraction Osteotomy With Subaxial Cervical Pedicle Screw Fixation

Patients suffering from ankylosing spondylitis are not only predisposed to the development of rigid cervicothoracic deformities but are also at an increased risk of cervical fractures. Deformity correction and stabilization are particularly challenging in this patient population due to the brittle bone quality and low bone mineral density. Thoracic pedicle subtraction osteotomy is a workhorse approach for the correction of focal severe kyphotic deformity with lower complication rates than 3-column osteotomy. Successful execution of an upper thoracic PSO requires careful presurgical planning as well as anticipation of the patient's postoperative needs. Here, we describe the use of a T1 PSO in the correction of a rigid cervicothoracic chin-on-chest deformity in a patient with AS. The risk of implant failure was reduced by the use of a multi-rod construct, navigated cervical pedicle screws, and dual-pitched thoracic pedicle screws.

The Advantages of 4-rod Construct over the 2-rod Techniques in Adult Spinal Deformity Patients who Underwent Pedicle Subtraction Osteotomy: A Multicenter Retrospective Comparative Study

OBJECTIVE

In this retrospective study we compared clinicoradiologic outcomes and complication profiles of the traditional 2-rod construct versus the 4-rod construct in patients with adult spinal deformity (ASD) who underwent pedicle subtraction osteotomy (PSO).

METHODS

We performed a retrospective review of 208 ASD patients at 2 referral centers who underwent lumbar PSO and long fusion from thoracic to the pelvis. Two different techniques, including the 4-rod construct and the traditional 2-rod technique, were used at the PSO level. Clinicoradiologic outcomes and complication profiles of the patients were documented and compared statistically between the groups.

RESULTS

The 4-rod construct was associated with statistically lower rates of rod fracture (44.8% vs. 26.4%, P < 0.01), pedicular screw loosening at the PSO level (25.3% vs. 14.0%, P = 0.04), and reoperation (49.4% vs. 33.9%, P = 0.02). Radiologically, the 4-rod construct was associated with higher degree of lumbar lordosis (LL) (-37.4°vs. -26.8°; P < 0.01) and improved pelvic tilt (PT) (-17.2° vs. -9.9°; P < 0.01) and sacral vertical axis (SVA) corrections (-211.5° vs. -192.2°; P = 0.04). Overall, the 4-rod construct was associated with improved quality of life (P = 0.04) and statistically lower Oswestry Disability Index score at 12 months postoperatively (P < 0.01).

CONCLUSIONS

Our results showed that the 4-rod construct was associated with statistically lower rates of rod fracture and pedicular screw loosening at the osteotomy level, higher degree of LL correction and improved PT and SVA than the 2-rod technique. The 4-rod construct was also associated with improved quality of life and Oswestry Disability Index and lower complication profiles.

Comparison of complications, revisions, spinopelvic parameters, and health-related quality of life after posterior spinal fusion using multiple-rod constructs or two-rod constructs for adult spinal deformity: a systematic review and meta-analysis

BACKGROUND

The incidence of mechanical complications is high in patients undergoing posterior spinal fusion (PSF) for adult spinal deformity (ASD), especially for cases with severe sagittal malalignment or a prior spinal fusion requiring three-column osteotomy (3-CO) or spinopelvic fixation (SPF). The purpose of this systematic review and meta-analysis was to compare the complications, revisions, radiographic spinopelvic parameters, health-related quality of life (HRQoL), and surgical data of PSF using multiple-rod constructs to those of two-rod constructs for the treatment of ASD.

METHODS

A comprehensive literature search was performed for relevant studies in PubMed, EMBASE, Web of Science, and the Cochrane Library. Complications, revisions, spinopelvic parameters, HRQoL, and surgical date were compared between patients with ASD who underwent PSF using multiple-rod constructs (multi-rod group) and two-rod constructs (two-rod group).

RESULTS

Ten studies, comprising 797 patients with ASD (399 in the multi-rod group and 398 in the two-rod group), were included. All these studies were retrospective cohort studies. There were no significant differences in the surgical, wound-related, and systemic complications between the groups. In the multi-rod group, we noted a significantly lower incidence of rod fracture (RR, 0.43; 95% CI 0.33 to 0.57, P < 0.01), pseudoarthrosis (RR, 0.38; 95% CI 0.28 to 0.53, P < 0.01), and revisions (RR, 0.44; 95% CI 0.33 to 0.58, P < 0.01); a superior restoration of PI-LL (WMD, 3.96; 95% CI 1.03 to 6.88, P < 0.01) and SVA (WMD, 31.53; 95% CI 21.16 to 41.90, P < 0.01); a better improvement of ODI score (WMD, 6.82; 95% CI 2.33 to 11.31, P < 0.01), SRS-22 total score (WMD, 0.44; 95% CI 0.06 to 0.83, P = 0.02), and VAS-BP score (WMD, 1.02; 95% CI 0.31 to 1.73, P < 0.01).

CONCLUSION

Compared with the two-rod constructs, PSF using multiple-rod constructs was associated with a lower incidence of mechanical complications, a lower revision rate, a superior restoration of sagittal alignment, and a better improvement of HRQoL, without increasing surgical invasiveness. Multiple-rod constructs should be routinely considered to for ASD patients, especially for cases with severe sagittal malalignment or a prior spinal fusion requiring 3-CO or SPF.