Mid-long-term outcome and degeneration of the remaining unfused lumbar intervertebral disc in adolescent idiopathic scoliosis patients who had posterior spinal fusion surgery

Comparable rates of lumbar disc degeneration at long-term following adolescent idiopathic scoliosis spinal fusion extended to L3 or L4: systematic review and meta-analysis

PURPOSE

Surgical treatment of adolescent idiopathic scoliosis (AIS) requires a careful choice of fusion levels. The usual recommendation for the selection of the lowest instrumented vertebra (LIV) for double major or thoracolumbar/lumbar (TL/L) curves falls on L3 or L4. The aim of the present study is to assess if the spinal fusion with LIV selection of L3 or L4 in AIS patients has a clinical or radiological impact in terms of degenerative disc disease (DDD) in distal unfused segments at long-term follow-up.

METHODS

A systematic search of electronic databases from eligible articles was conducted. Only studies regarding long-term follow-up of AIS patients treated with spinal fusion were included. Clinical and radiographic outcomes were extracted and summarized. Meta-analysis on long-term follow-up MRI studies was performed. p value < 0.05 was considered significant.

RESULTS

Fourteen studies were included, for a total of 1264 patients. Clinical assessment of included patients showed a slight tendency to have worse clinical outcomes if spinal fusion is extended to L4 rather than L3. Despite that, meta-analysis could not be performed on clinical parameters because of heterogeneity of evaluated PROMs in included studies. Magnetic resonance imaging (MRI) evaluation at long-term follow-up showed no significant difference in terms of disc degeneration rate at overall meta-analysis (p = 0.916) between patients fused to L3 and L4.

CONCLUSION

The LIV selection of L3 rather than L4, according to current literature, does not prevent disc degeneration in distal unfused segments over the long term. Long-term studies of patients treated with contemporary spinal instrumentation are needed.

Incidence and risk factors of distal adjacent disc degeneration in adolescent idiopathic scoliosis patients undergoing fusion surgery: a systematic review and meta-analysis

PURPOSE

The objective of this meta-analysis was to determine the incidence of disc degeneration in patients with surgically treated adolescent idiopathic scoliosis (AIS) and identify the associated risk factors.

METHODS

PubMed, EMBASE, Scopus, and Cochrane Collaboration Library databases were searched. The outcomes of interest were the incidence of disc degeneration, SRS-22, and radiological risk factors. The lower instrumented vertebra (LIV) was also evaluated. Fixed effects were used if there was no evidence of heterogeneity. Statistical analysis was performed using Review Manager.

RESULTS

A meta-analysis was conducted including nine studies with a total of 565 patients. The analysis revealed that the global incidence of intervertebral disc degeneration in patients with surgically treated AIS patients was 24.78% (95% CI 16.59-32.98%) 10 years after surgery, which significantly increased to 32.32% (95% CI 21.16-43.47% at an average of 13.8 years after surgery. Among patients with significant degenerative disc changes, the SRS-22 functional, self-image, and satisfaction domains showed significantly worse results (MD - 0.25, 95% CI - 0.44 to - 0.05; MD - 0.50, 95% CI - 0.75 to - 0.25; and MD - 0.34, 95% CI - 0.66 to - 0.03, respectively). Furthermore, instrumentation at or above the L3 level was associated with a lower incidence of intervertebral disc degeneration compared to instrumentation below the L3 level (OR 0.25, 95% CI 0.10-0.64). It was also found that the preoperative and final follow-up lumbar curve magnitudes (MD 8.11, 95% CI 3.82-12.41) as well as preoperative and final follow-up lumbar lordosis (MD 0.42, 95% CI - 3.81 to 4.65) were associated with adjacent disc degeneration.

CONCLUSIONS

This meta-analysis demonstrated that the incidence of intervertebral disc degeneration significantly increased with long-term follow-up using fusion techniques, reaching up to 32% when patients were 28 years of age. Incomplete correction of deformity and fusion of levels below L3, were identified as negative prognostic factors. Furthermore, patients with disc degeneration showed worse functional outcomes.

Half of the adolescent idiopathic scoliosis patients may have lumbar adjacent segment degeneration following spinal fusion: A systemic review and meta-analysis

OBJECTIVE

This study aims to assess the impact of surgical approaches and other factors on the incidence of Adjacent Segment Degeneration (ASD) following Spinal Fusion for Adolescent Idiopathic Scoliosis (AIS).

METHODS

We conducted a comprehensive search of four electronic databases from their inception until March 30, 2023. Two independent reviewers screened titles, abstracts, and full texts and evaluated the methodological quality of the studies. A random-effects model was used to calculate the incidence of ASD.

RESULTS

Our analysis included 14 studies involving 651 individuals. The overall incidence of ASD was 47% (95%CI: 0.37, 0.56). Subgroup analyses revealed that the prevalence of ASD increased with postoperative time (53% (95%CI: 0.31, 0.75) versus 48% (95%CI: 0.36, 0.60) versus 39% (95%CI: 0.22, 0.56)). For the number of fused segments, a group with more than 10 segments had a higher prevalence (49% (95%CI: 0.38, 0.60) versus 44% (95%CI: 0.21, 0.69)). In terms of regions, East Asia had the highest prevalence, followed by Occident and West Asia (52% (95%CI: 0.41, 0.62) versus 43% (95%CI: 0.20, 0.68) versus 37% (95%CI: 0.17, 0.59)). However, the surgical approach, male ratio, and the position of the lowest instrumented vertebra (LIV) did not show significant differences between groups. Funnel plots and Egger's test did not reveal any significant publication bias (Egger's test: t = 1.62, p-value = .1274).

CONCLUSION

This meta-analysis found that nearly half of AIS patients following spinal fusion surgery experienced ASD. Long-term follow-up, regular screening, and timely interventions are essential to reduce the prevalence of ASD.

Adolescent idiopathic scoliosis with concomitant spondylolysis: choice of fusion levels and evaluation of the outcomes obtained leaving the lytic level not instrumented

PURPOSE

7% of adolescent idiopathic scoliosis (AIS) patients also present with a pars defect. To date, there are no available data on the results of fusion ending proximal to a spondylolysis in the setting of AIS. The aim of this study was to analyze the outcomes of posterior spinal fusion (PSF) in this patient cohort, to investigate if maintaining the lytic segment unfused represents a safe option.

METHODS

Retrospective review of all patients who received PSF for AIS, presented with a spondylolysis or spondylolisthesis and had a min. 2-year follow-up. Demographic data, instrumented levels, and preoperative radiographic data were collected. Mechanical complications, coronal or sagittal parameters, amount of slippage, and pain levels were evaluated.

RESULTS

Data from 22 patients were available (age 14.4 ± 2.5 years), 18 Lenke 1-2 and 4 Lenke 3-6. 5 patients (24%) had an isthmic spondylolisthesis, all Meyerding I. The mean preoperative Cobb angle of the instrumented curves was 58 ± 13°. For 18 patients, the lowest instrumented vertebra (LIV) was the last touched vertebra (LTV); for 2, LIV was distal to the LTV; for 2, LIV was one level proximal to the LTV. The number of segments between the LIV and the lytic vertebra ranged from 1 to 6. At the last follow-up, no complications were observed. The residual curve below the instrumentation measured 8.5 ± 6.4°, the lordosis below the instrumented levels was 51.4 ± 13°. The magnitude of the isthmic spondylolisthesis remained constant for all included patients. Three patients reported minimal occasional low back pain.

CONCLUSION

The LTV can be safely used as LIV when performing PSF for the management of AIS in patients with L5 spondylolysis.

Long-term adjacent segment degeneration at average 21-year follow-up of posterior instrumented fusion for adolescent idiopathic scoliosis

INTRODUCTION

Posterior instrumented fusion for progressive adolescent idiopathic scoliosis (AIS) is generally considered to have good outcomes, but very long-term reviews are rare. Data on adjacent segment degeneration (ASD) following posterior instrumented thoracic fusion for AIS are lacking. The primary aim was to assess the incidence of ASD and to correlate this with radiographic measures and patient-reported outcome measures (PROMs). The secondary aim was to assess maintenance of curve correction at very long-term follow-up.

METHODS

This single-surgeon consecutive case series of 47 AIS patients was identified from a prospectively collated dataset. As the primary outcome, ASD was assessed radiographically using the Mimura grading system. Pulmonary function tests and PROMs were assessed along with secondary radiographic outcome measures.

RESULTS

Radiographic follow-up was achieved in 77% (36/47) of patients at an average of 21 years (range, 16.5-26.5 years) after surgery. Radiographic evidence of ASD was seen in 64%. PROMs showed a mean Oswestry disability index of 12.1% with an overall Scoliosis Research Society 22 score averaging at 3.7 out of 5. The Coronal Cobb Angle was corrected from an average of 57° preoperatively to 19° immediately postoperatively, deteriorating to 22° at final review, maintaining a 61% curve correction.

CONCLUSIONS

Radiographic evidence of ASD was found in 64% of the cohort. The patient-reported outcome measures were good, with few limitations to activities.

At Mean 30-Year Follow-Up, Cervical Spine Disease Is Common and Associated with Thoracic Hypokyphosis after Pediatric Treatment of Adolescent Idiopathic Scoliosis

Patients with adolescent idiopathic scoliosis (AIS) often have reduced sagittal thoracic kyphosis (hypokyphosis) and cervical lordosis causing an uneven distribution of physiologic load. However, the long-term consequences of hypokyphosis in AIS patients have not been previously documented. To evaluate whether uneven load distribution leads to future complications in patients with AIS, we conducted a retrospective chart review and subsequently surveyed 180 patients treated for idiopathic scoliosis between 1975 and 1992. These patients all had a minimum follow-up time of 20 years since their treatment. We observed a ten-fold increase in the incidence of anterior cervical discectomy and fusion (ACDF) compared to reported rates in the non-pathologic population. Out of the 180 patients, 33 patients met the criteria and returned for follow-up radiographs. This population demonstrated a statistically significant increased rate of cervical osteoarthritis and disc degeneration. Overall, our study suggests that hypokyphosis in patients with AIS presents with increased rates of cervical spine degeneration and dysfunction, suggesting that these patients may require additional follow-up and treatment.

Evaluation of Staphylococcus aureus and Candida albicans biofilms adherence to PEEK and titanium-alloy prosthetic spine devices

BACKGROUND

Titanium and polyether-ether-ketone (PEEK) interbody cages are commonly used for spine fusion. Few data are known about bacterial and yeast biofilms formation in these implants. The aim of this study was to compare Staphylococcus aureus and Candida albicans biofilm formation in the surface of two different interbody devices used routinely in spine surgery.

METHODS

Six bodies of proof specimens of PEEK and titanium alloy were used for microbiological tests, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Experimental biofilm was produced with Staphylococcus aureus and Candida albicans, followed by quantitative analysis of planktonic cells and sessile cells. The comparison between the medians of biofilm quantification between the two models was performed using the Mann-Whitney test and considered the statistical difference for a p < 0.05.

RESULTS

In the S. aureus model, in both planktonic and sessile cell counts, titanium-alloy samples showed lower values for colony forming units per milliliter (UFC/mL) (p < 0.05). The evaluation through the optic density of planktonic and sessile cells showed lower values in the titanium-alloy samples, however, only statistically significant in planktonic cell count (p < 0.05). The count of planktonic yeast cells in PEEK was similar to titanium-alloy samples, while the count of sessile yeast cells in titanium alloy was lower when compared to PEEK (p < 0.05).

CONCLUSION

Titanium-alloy models were associated with less staphylococcal and Candida biofilm formation when compared with PEEK.