PLF+PS or ALIF+PS: which has a lower operative nonunion rate? Analysis of a cohort of 2,061 patients from a National Spine Registry

Primary anterior lumbar interbody fusion, with and without posterior instrumentation: a 1,377-patient cohort from a multicenter spine registry

BACKGROUND CONTEXT

Lumbar interbody instrumentation techniques are common and effective surgical options for a variety of lumbar degenerative pathologies. Anterior lumbar interbody fusion (ALIF) has become a versatile and powerful means of decompression, stabilization, and reconstruction. As an anterior only technique, the integrity of the posterior muscle and ligaments remain intact. Adding posterior instrumentation to ALIF is common and may confer benefits in terms of higher fusion rate but could contribute to adjacent segment degeneration due to additional rigidity. Large clinical studies comparing stand-alone ALIF with and without posterior supplementary fixation (ALIF+PSF) are lacking.

PURPOSE

To compare rates of operative nonunion and adjacent segment disease (ASD) in ALIF with or without posterior instrumentation.

STUDY DESIGN

Retrospective cohort study.

PATIENT SAMPLE

Adult patients (≥18 years old) who underwent primary ALIF for lumbar degenerative pathology between levels L4 to S1 over a 12-year period. Exclusion criteria included trauma, cancer, infection, supplemental decompression, noncontiguous fusions, prior lumbar fusions, and other interbody devices.

OUTCOME MEASURES

Reoperation for nonunion and ASD compared between ALIF only and ALIF+PSF.

METHODS

Reoperations were modeled as time-to-events where the follow-up time was defined as the difference between the primary ALIF procedure and the date of the outcome of interest. Crude cumulative reoperation probabilities were reported at 5-years follow-up. Multivariable Cox proportional hazard regression was used to evaluate risk of operative nonunion and for ASD adjusting for patient characteristics.

RESULTS

The study consisted of 1,377 cases; 307 ALIF only and 1070 ALIF+PSF. Mean follow-up time was 5.6 years. The 5-year crude nonunion incidence was 2.4% for ALIF only and 0.5% for ALIF+PSF; after adjustment for covariates, a lower operative nonunion risk was observed for ALIF+PSF (HR=0.22, 95% CI=0.06-0.76). Of the patients who are deemed potentially suitable for ALIF alone, one would need to add posterior instrumentation in 53 patients to prevent one case of operative nonunion at a 5-year follow-up (number needed to treat). Five-year operative ASD incidence was 4.3% for ALIF only and 6.2% for ALIF+PSF; with adjustments, no difference was observed between the cohorts (HR=0.96, 95% CI=0.54-1.71).

CONCLUSIONS

While the addition of posterior instrumentation in ALIFs is associated with lower risk of operative nonunion compared with ALIF alone, operative nonunion is rare in both techniques (<5%). Accordingly, surgeons should evaluate the added risks associated with the addition of posterior instrumentation and reserve the supplemental posterior fixation for patients that might be at higher risk for operative nonunion. Rates of operative ASD were not statistically higher with the addition of posterior instrumentation suggesting concern regarding future risk of ASD perhaps should not play a role in considering supplemental posterior instrumentation in ALIF.

Trends in Reimbursement and Approach Selection for Lumbar Arthrodesis

BACKGROUND

Changes in reimbursement policies have been demonstrated to correlate with clinical practice.

OBJECTIVE

To investigate trends in physician reimbursement for anterior, posterior, and combined anterior/posterior (AP) lumbar arthrodesis and relative utilization of AP.

METHODS

We queried the American College of Surgeons National Surgical Quality Improvement Project registry for anterior, posterior, and AP lumbar arthrodeses during 2010 and 2020. Work relative value units per operative hour (wRVUs/h) were calculated for each procedure. Trends in reimbursement and utilization of the AP approach were assessed with linear regression. Subgroup analyses of age and underlying pathology of AP arthrodesis were also performed.

RESULTS

During 2010 and 2020, AP arthrodesis was associated with significantly higher average wRVUs/h compared with anterior and posterior arthrodesis (AP = 17.4, anterior = 12.4, posterior = 14.5). The AP approach had a significant yearly increase in wRVUs/h (coefficient = 0.48, P = .042), contrary to anterior (coefficient = -0.01, P = .308) and posterior (coefficient = -0.13, P = .006) approaches. Utilization of AP approaches over all arthrodeses increased from 7.5% in 2010 to 15.3% in 2020 (yearly average increase 0.79%, P < .001). AP fusions increased significantly among both degenerative and deformity cases (coefficients 0.88 and 1.43, respectively). The mean age of patients undergoing AP arthrodesis increased by almost 10 years from 2010 to 2020. Rates of major 30-day complications were 2.7%, 3.1%, and 3.5% for AP, anterior, and posterior arthrodesis, respectively.

CONCLUSION

AP lumbar arthrodesis was associated with higher and increasing reimbursement (wRVUs/h) during the period 2010 to 2020. Reimbursement for anterior arthrodesis was relatively stable, while reimbursement for posterior arthrodesis decreased. The utilization of the combined AP approach relative to the other approaches increased significantly during the period of interest.

Concurrent Treatment with Vitamin K2 and D3 on Spine Fusion in Patients with Osteoporosis-Associated Lumbar Degenerative Disorders

STUDY DESIGN

A prospective and nonrandomized concurrent controlled trial.

OBJECTIVE

To address the early effects of concurrent treatment with vitamin K2 and vitamin D3 on fusion rates in patients who have undergone spinal surgery.

SUMMARY OF BACKGROUND DATA

Intervertebral pseudarthrosis has been reported after transforaminal lumbar interbody fusion (TLIF) or posterior lumbar interbody fusion (PLIF), especially in patients with osteopenia or osteoporosis. No study has assessed the early effects of concurrent treatment with vitamin K2 and vitamin D3 on fusion rates.

METHODS

Patients with osteopenia or osteoporosis who underwent TLIF or PLIF in our department were included. Patients in the VK2+VD3 group received vitamin K2, vitamin D3, and calcium treatment, whereas subjects in the control group only received calcium and vitamin D3. Spine fusion was evaluated by computed tomography. The Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOA-BPEQ) and visual analog scale (VAS) were used to assess the clinical and neurological symptoms. Bone mineral density (BMD) and bone metabolism markers were measured for osteoporotic evaluation.

RESULTS

Seventy-eight patients were included, and nine patients subsequently discontinued because of 2019-nCoV. At six months postoperatively, complete fusion rates were significantly higher in the VK2+VD3 group than that in the control group (91.18% vs 71.43%, P = 0.036). At six months postoperatively, BMD was increased in the VK2+VD3 group and was higher than that in the control group, although there was no significant difference. At three months postoperatively, a significant increase in procollagen type I amino terminal propeptide (91.81%) and a slight decrease in C-terminal end peptide (8.06%) were observed in the VK2+VD3 group. In both groups, the JOA-BPEQ and VAS scores were significantly improved after spine surgery.

CONCLUSION

Administration of vitamin K2 and vitamin D3 can increase lumbar interbody fusion rates, improve clinical symptoms, promote bone information, and avoid further decline in BMD within six months after TLIF or PLIF.Level of Evidence: 3.