Reoperation within 2 years after lumbar interbody fusion: a multicenter study

Risk factors for early-onset adjacent segment degeneration after one-segment posterior lumbar interbody fusion

Adjacent segment degeneration (ASD) is a major postoperative complication associated with posterior lumbar interbody fusion (PLIF). Early-onset ASD may differ pathologically from late-onset ASD. The aim of this study was to identify risk factors for early-onset ASD at the cranial segment occurring within 2 years after surgery. A retrospective study was performed for 170 patients with L4 degenerative spondylolisthesis who underwent one-segment PLIF. Of these patients, 20.6% had early-onset ASD at L3-4. In multivariate logistic regression analysis, preoperative larger % slip, vertebral bone marrow edema at the cranial segment on preoperative MRI (odds ratio 16.8), and surgical disc space distraction (cut-off 4.0 mm) were significant independent risk factors for early-onset ASD. Patients with preoperative imaging findings of bone marrow edema at the cranial segment had a 57.1% rate of early-onset ASD. A vacuum phenomenon and/or concomitant decompression at the cranial segment, the degree of surgical reduction of slippage, and lumbosacral spinal alignment were not risk factors for early-onset ASD. The need for fusion surgery requires careful consideration if vertebral bone marrow edema at the cranial segment adjacent to the fusion segment is detected on preoperative MRI, due to the negative impact of this edema on the incidence of early-onset ASD.

Risk factors for early reoperation in patients after posterior lumbar interbody fusion surgery. A propensity-matched cohort analysis

BACKGROUND

Reoperation is usually associated with poor results and increased morbidity and hospital costs. However, the rates, causes, and risk factors for reoperation in patients undergoing lumbar spinal fusion surgery remain controversial. This study aimed to identify the risk factors for early reoperation after posterior lumbar interbody fusion surgery and to compare the clinical outcomes between patients who underwent reoperation and those who did not.

METHODS

We investigated a multicenter medical record database of 1263 patients who underwent posterior lumbar interbody fusion surgery between 2012 and 2015. A total of 72 (5.7%) reoperations within two years after surgery were identified and were propensity-matched for age, sex, number of fusion segments, and surgeon's experience.

RESULTS

We analyzed a total of 114 patients (57 who underwent reoperation (R group) and 57 who did not (C group)). The mean age was 62.6 ± 13.4 years, with 78 men and 36 women. The mean number of fused segments was 1.2 ± 0.5. Surgical site infection was the most common cause of reoperation. There were significant differences in the incidence of diabetes mellitus (p = 0.024), preoperative ambulation status (p = 0.046), and ASA grade (p < 0.001) between the C and R groups. The recovery rate of the Japanese Orthopaedic Association score was significantly lower in the R group compared to the C group (R: 50.5 ± 28.8%, C: 63.9 ± 33.7%, p = 0.024). There were significant differences in the bone fusion rate (R: 63.2%, C: 96.5%, p < 0.001) and incidence of screw loosening (R: 31.6%; C: 10.5%; p = 0.006).

CONCLUSION

Diabetes mellitus, preoperative ambulation status, and ASA grade were significant risk factors for early reoperation following posterior lumbar interbody fusion surgery. The patients who underwent early reoperation had worse clinical outcomes than those who did not.

Incidence of Surgical Site Infection Following Lateral Lumbar Interbody Fusion Compared With Posterior/Transforaminal Lumbar Interbody Fusion: A Propensity Score-Weighted Study

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

The objective of this study was to compare the incidence of surgical site infection (SSI) after lateral lumbar interbody fusion (LLIF) and posterior/transforaminal lumbar interbody fusion ( P /TLIF).

SUMMARY OF BACKGROUND DATA

Previous studies have shown that LLIF can improve neurological symptoms to a comparable degree to P /TLIF. However, data on the risk of SSI after LLIF is lacking compared with P /TLIF.

MATERIALS AND METHODS

The study was conducted under a retrospective cohort design in patients undergoing LLIF or P /TLIF for lumbar degenerative diseases between 2013 and 2020 using a hospital administrative database. We used propensity score overlap weighting to adjust for confounding factors including age, sex, body mass index, comorbidities, number of fusion levels, hospital size, and surgery year. We estimated weighted odds ratios (ORs) and 95% CIs for SSI within 30 days postoperatively.

RESULTS

We compared the risk of SSI between 2874 patients who underwent LLIF and 24,245 patients who received P/TLIF Patients who had received LLIF were at significantly less risk of experiencing an SSI compared with those receiving P/TLIF (0.7% vs. 1.2%; weighted OR: 0.57; 95% CI: 0.36 -0.92; P=0.02). As a secondary outcome, patients who had received LLIF had less risk of transfusion (7.8% vs. 11.8%; weighted OR: 0.63; 95% CI:0.54 -0.73; P <0.001).

CONCLUSIONS

In this large retrospective cohort study of adults undergoing lumbar interbody fusion, LLIF was associated with a significantly lower risk of SSI than P /TLIF. The small, but significantly, decreased risk of SSI associated with LLIF may inform decisions regarding the technical approach for lumbar interbody fusion.

Lateral lumbar interbody fusion (LLIF) reduces total lifetime cost compared with posterior lumbar interbody fusion (PLIF) for single-level lumbar spinal fusion surgery: a cost-utility analysis in Thailand

BACKGROUND

Lumbar interbody fusion techniques treat degenerative lumbar diseases effectively. Minimally invasive lateral lumbar interbody fusion (LLIF) decreases soft tissue disruption and accelerates recovery better than standard open posterior lumbar interbody fusion (PLIF). However, the material cost of LLIF is high, especially in Thailand. The cost-effectiveness of LLIF and PLIF in developing countries is unclear. This study compared the cost-utility and clinical outcomes of LLIF and PLIF in Thailand.

METHODS

Data from patients with lumbar spondylosis who underwent single-level LLIF and PLIF between 2014 and 2020 were retrospectively reviewed. Preoperative and 1-year follow-up EuroQol-5D-5L and healthcare costs were collected. A cost-utility analysis with a lifetime time horizon was performed using a societal perspective. Outcomes are reported as the incremental cost-effectiveness ratio (ICER) and quality-adjusted life-year (QALY) gained. A Thai willingness-to-pay threshold of 5003 US dollars (USD) per QALY gained was used.

RESULTS

The 136 enrolled patients had a mean age of 62.26 ± 11.66 years. Fifty-nine patients underwent LLIF, while 77 underwent PLIF. The PLIF group experienced greater estimated blood loss (458.96 vs 167.03 ml; P < 0.001), but the LLIF group had a longer operative time (222.80 vs 194.62 min; P = 0.007). One year postoperatively, the groups' Oswestry Disability Index and EuroQol-Visual Analog Scale scores were improved without statistical significance. The PLIF group had a significantly better utility score than the LLIF group (0.89 vs 0.84; P = 0.023). LLIF's total lifetime cost was less than that of PLIF (30,124 and 33,003 USD). Relative to PLIF, LLIF was not cost-effective according to the Thai willingness-to-pay threshold, with an ICER of 19,359 USD per QALY gained.

CONCLUSIONS

LLIF demonstrated lower total lifetime cost from a societal perspective. Regard to our data, at the 1-year follow-up, the improvement in patient quality of life was less with LLIF than with PLIF. Additionally, economic evaluation modeling based on the context of Thailand showed that LLIF was not cost-effective compared with PLIF. A strategy that facilitates the selection of patients for LLIF is required to optimize patient benefits.

A Risk Calculator for the Prediction of C5 Nerve Root Palsy After Instrumented Cervical Fusion

BACKGROUND

C5 palsy is a common postoperative complication after cervical fusion and is associated with increased health care costs and diminished quality of life. Accurate prediction of C5 palsy may allow for appropriate preoperative counseling and risk stratification. We primarily aim to develop an algorithm for the prediction of C5 palsy after instrumented cervical fusion and identify novel features for risk prediction. Additionally, we aim to build a risk calculator to provide the risk of C5 palsy.

METHODS

We identified adult patients who underwent instrumented cervical fusion at a tertiary care medical center between 2013 and 2020. The primary outcome was postoperative C5 palsy. We developed ensemble machine learning, standard machine learning, and logistic regression models predicting the risk of C5 palsy-assessing discrimination and calibration. Additionally, a web-based risk calculator was built with the best-performing model.

RESULTS

A total of 1024 patients were included, with 52 cases of C5 palsy. The ensemble model was well-calibrated and demonstrated excellent discrimination with an area under the receiver-operating characteristic curve of 0.773. The following features were the most important for ensemble model performance: diabetes mellitus, bipolar disorder, C5 or C4 level, surgical approach, preoperative non-motor neurologic symptoms, degenerative disease, number of fused levels, and age.

CONCLUSIONS

We report a risk calculator that generates patient-specific C5 palsy risk after instrumented cervical fusion. Individualized risk prediction for patients may facilitate improved preoperative patient counseling and risk stratification as well as potential intraoperative mitigating measures. This tool may also aid in addressing potentially modifiable risk factors such as diabetes and obesity.

Incidence and risk factors for early and late reoperation following lumbar fusion surgery

STUDY DESIGN

Retrospective cohort study.

PURPOSE

The aim of our study was to determine the rates and indications of reoperations following primary lumbar fusion, as well as the independent risk factors for early and late reoperation.

METHODS

We retrospectively reviewed patients who underwent lumbar fusion surgery between January 2017 and March 2020. All patients were followed up for more than 2 years. Characteristics, laboratory tests, primary diagnosis and surgery-related variables were compared among the early reoperation (< 3 months), the late reoperation (> 3 months) and the non-reoperation groups. Multivariable logistic regression analysis was used to identify independent risk factors for early and late reoperations.

RESULTS

Of 821 patients included in our studies, 34 patients underwent early reoperation, and 36 patients underwent late reoperation. The cumulative reoperation rate was about 4.1% (95% CI 3.8-4.5%) at 3 months, 6.2% (95% CI 5.9-6.5%) at 1 year and 8.2% (95% CI 8.0-8.5%) at 3 years. Multivariable analysis indicated that osteoporosis (odds ratio [OR] 3.6, 95% CI 1.2-10.5, p = 0.02) and diabetes (OR 2.1, 95% CI 1.1-4.5, p = 0.04) were independently associated with early reoperation and multilevel fusion (OR 2.4, 95% CI 1.1-5.4, p = 0.03) was independently associated with late reoperation.

CONCLUSIONS

The most common reasons for early reoperation and late operation were surgical site infection and adjacent segment diseases, respectively. Osteoporosis and diabetes were independent risk factors for early reoperation, and multilevel fusion was independent risk factor for late reoperation. Surgeons should pay more attention to these patients, and future studies should consider the effects of follow-up periods on results.

Biomechanical Comparison of Salvage Pedicle Screw Augmentations Using Different Biomaterials

Allograft bone particles, hydroxyapatite/β-hydroxyapatite-tricalcium phosphate (HA/β-TCP), calcium sulfate (CS), and polymethylmethacrylate (PMMA) bone cement are biomaterials clinically used to fill defective pedicles for pedicle screw augmentation. Few studies have systematically investigated the effects of various biomaterials utilized for salvage screw stabilization. The aim of this study was to evaluate the biomechanical properties of screws augmented with these four different materials and the effect of different pilot hole sizes and bone densities on screw fixation strength. Commercially available synthetic bones with three different densities (7.5 pcf, 15pcf, 30 pcf) simulating different degrees of bone density were utilized as substitutes for human bone. Two different pilot hole sizes (3.2 mm and 7.0 mm in diameter) were prepared on test blocks to simulate primary and revision pedicle screw fixation, respectively. Following separate specimen preparation with these four different filling biomaterials, a screw pullout test was conducted using a material test machine, and the average maximal screw pullout strength was compared among groups. The average maximal pullout strength of the materials, presented in descending order, was as follows: bone cement, calcium sulfate, HA/β-TCP, allograft bone chips and the control. In samples in both the 3.2 mm pilot-hole and 7.0 mm pilot-hole groups, the average maximal pullout strength of these four materials increased with increasing bone density. The average maximal pullout strength of the bone cement augmented salvage screw (7.0 mm) was apparently elevated in the 7.5 pcf test block. Salvage pedicle screw augmentation with allograft bone chips, HA/β-TCP, calcium sulfate, and bone cement are all feasible methods and can offer better pullout strength than materials in the non-augmentation group. Bone cement provides the most significantly augmented effect in each pilot hole size and bone density setting and could be considered preferentially to achieve larger initial stability during revision surgery, especially for bones with osteoporotic quality.

Early Reoperation Rates and Its Risk Factors after Instrumented Spinal Fusion Surgery for Degenerative Spinal Disease: A Nationwide Cohort Study of 65,355 Patients

Reoperation is a major concern in spinal fusion surgery for degenerative spinal disease. Earlier reported reoperation rates were confined to a specific spinal region without comprehensive analysis, and their prediction models for reoperation were not statistically validated. Our study aimed to present reasonable base rates for reoperation according to all possible risk factors and build a validated prediction model for early reoperation. In our nationwide population-based cohort study, data between 2014 and 2016 were obtained from the Korean National Health Insurance claims database. Patients older than 19 years who underwent instrumented spinal fusion surgery for degenerative spinal diseases were included. The patients were divided into cases (patients who underwent reoperation) and controls (patients who did not undergo reoperation), and risk factors for reoperation were determined by multivariable analysis. The estimates of all statistical models were internally validated using bootstrap samples, and sensitivity analyses were additionally performed to validate the estimates by comparing the two prediction models (models for 1st-year and 3rd-year reoperation). The study included 65,355 patients: 2939 (4.5%) who underwent reoperation within 3 years after the index surgery and 62,146 controls. Reoperation rates were significantly different according to the type of surgical approach and the spinal region. The third-year reoperation rates were 5.3% in the combined lumbar approach, 5.2% in the posterior lumbar approach, 5.0% in the anterior lumbar approach, 3.0% in the posterior thoracic approach, 2.8% in the posterior cervical approach, 2.6% in the anterior cervical approach, and 1.6% in the combined cervical approach. Multivariable analysis identified older age, male sex, hospital type, comorbidities, allogeneic transfusion, longer use of steroids, cages, and types of surgical approaches as risk factors for reoperation. Clinicians can conduct comprehensive risk assessment of early reoperation in patients who will undergo instrumented spinal fusion surgery for degenerative spinal disease using this model.

Cement discoplasty for managing lumbar spine pseudarthrosis in elderly patients: a less invasive alternative approach for failed posterior lumbar spine interbody fusion

PURPOSE

A retrospective cohort study was performed to evaluate pseudoarthrosis treatment results by injection of cement in disc space of failed fusion in posterior lumbar interbody fusion in patients above 65 years.

METHODS

Forty-five patients above 65 years with symptomatic pseudarthrosis after lumbar spine fusion were treated by cement injection in the affected disc space.

RESULTS

There were 30 females and 15 males. The mean age at the operation was 74 ± 6.5 years (range 65-89). Discoplasty was performed after the primary fusion operations after a mean of 14 ± 1.3 months (range 12-24). The mean preoperative VAS was 7.5 (range 6-9), and ODI was 36 (range 30-45). Cement injection was done at one level in most of the cases (35 patients). In seven cases, two injection levels were done, and in three cases, three levels. Twenty-three patients had discoplasty only, while 22 had discoplasty and screws change, including 14 cases of extension of the instrumentation. The mean postoperative follow-up was 32 ± 6.5 months. The VAS improved to 3.5 (range 2-5) (p = 0.02) and ODI to 12.3 (range 5-35) (p = 0.001). Reoperation was indicated in two (4%) patients by screws loosening. Asymptomatic cement leakage occurred in the paravertebral space in seven cases (15.5%).

CONCLUSION

Cement discoplasty offers a less invasive reliable surgical solution in elderly patients with symptomatic lumbar pseudarthrosis in the elderly patients. In cases with screw loosening, discoplasty should be combined with screw revision.

Diabetes Is Predictive of Postoperative Outcomes and Readmission Following Posterior Lumbar Fusion

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

The present study analyzes complication rates and episode-based costs for patients with and without diabetes mellitus (DM) following posterior lumbar fusion (PLF).

METHODS

PLF cases at a single institution from 2008 to 2016 were queried (n = 3226), and demographic and perioperative data were analyzed. Patients with and without the diagnosis of DM were compared using chi-square, Student's t test, and multivariable regression modeling.

RESULTS

Patients with diabetes were older (63.10 vs 56.48 years, P < .001) and possessed a greater number of preoperative comorbidities (47.84% of patients had Elixhauser Comorbidity Index >0 vs 42.24%, P < .001) than did patients without diabetes. When controlling for preexisting differences, diabetes remained a significant risk factor for prolonged length of stay (OR = 1.59, 95% CI 1.26-2.01, P < .001), intensive care unit stay (OR = 1.52, 95% CI 1.07-2.17, P = .021), nonhome discharge (OR = 1.86, 95% CI 1.46-2.37, P < .001), 30-day readmission (OR = 2.15, 95% CI 1.28-3.60, P = .004), 90-day readmission (OR = 1.65, 95% CI 1.05-2.59, P = .031), 30-day emergency room visit (OR = 2.15, 95% CI 1.27-3.63, P = .004), and 90-day emergency room visit (OR = 2.27, 95% CI 1.41-3.65, P < .001). Cost modeling controlling for overall comorbidity burden demonstrated that diabetes was associated with a $1709 increase in PLF costs (CI $344-$3074, P = .014).

CONCLUSIONS

The present findings indicate a correlation between diabetes and a multitude of postoperative adverse outcomes and increased costs, thus illustrating the substantial medical and financial burdens of diabetes for PLF patients. Future studies should explore preventive measures that may mitigate these downstream effects.

Minimally invasive transforaminal lumbar interbody fusion using the biportal endoscopic techniques versus microscopic tubular technique

BACKGROUND CONTEXT

Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) with microscopic tubular technique is an established surgical procedure with several potential advantages, including decreased surgical-related morbidity, reduced length of hospital stay, and accelerated early rehabilitation. A recently introduced biportal endoscopic technique for spine surgery presents familiar surgical anatomy and can be conducted using a conventional approach with a minimal footprint; it is also applicable to TLIF.

PURPOSE

To compare the clinical and radiological outcomes of biportal endoscopic technique transforaminal lumbar interbody fusion (BE-TLIF) and microscopic tubular technique transforaminal lumbar interbody (MT-TLIF) in patients with single- or two-segment lumbar spinal stenosis with or without spondylolisthesis.

STUDY DESIGN

A retrospective cohort study.

PATIENT SAMPLE

One hundred two participants with neurogenic intermittent claudication or lumbar radiculopathy with single- or two-level lumbar spinal stenosis with or without spondylolisthesis.

OUTCOME MEASURES

Clinical outcomes were assessed using the visual analog scale (VAS) score for the back and leg pain, Oswestry Disability Index (ODI), and the Short Form-36 health survey Questionnaire (SF-36). Demographic data, operative data (total operation time, estimated blood loss, amount of surgical drain, postoperative transfusion, and length of hospital stay), and laboratory results (plasma hemoglobin, serum creatine phosphokinase, and C-reactive protein) were also evaluated. The fusion rate was assessed using the Bridwell interbody fusion grading system. Postoperative complications were also noted.

METHODS

Patients were divided into two groups: group A (BE-TLIF) and group B (MT-TLIF). The clinical outcomes, including VAS-Back and VAS-Leg, ODI, and SF-36 scores, were evaluated at 1 month, 6 months, and 1 year after surgery. Differences in demographics, operative data, and the laboratory and radiological results were assessed between the two groups. The fusion rate was assessed using standard standing lumbar radiographs and computed tomography scans conducted 1 year after surgery.

RESULTS

Seventy-nine patients were analyzed in this study, 47 from group A and 32 from group B. Demographic and operative data were comparable for both the groups. The VAS-Back and SF-36 scores were more significantly improved in group A than in group B at 1 month after surgery. However, there were no significant differences between groups for the mean VAS-Back, VAS-Leg, ODI, and SF-36 scores at 1year after the surgery. Although the total operation time was significantly longer in group A, the estimated blood loss and the amount of surgical drainage was significantly higher in group B (p < .001). There were no between-group differences for the fusion rate and postoperative complications.

CONCLUSION

Both BE-TLIF and MT-TLIF provided equivalent and favorable clinical outcomes and fusion rates. Further large-scale, randomized, controlled trials with long-term follow-ups are warranted.

Effect of segmental lordosis on early-onset adjacent-segment disease after posterior lumbar interbody fusion

OBJECTIVE

Although several reports have described adjacent-segment disease (ASD) after posterior lumbar interbody fusion (PLIF), there have been only a few reports focusing on early-onset ASD occurring within 3 years after primary PLIF. The purpose of this study was to investigate the prevalence and postoperative pathologies of early-onset ASD and its relation with radiological parameters such as segmental lordosis (SL).

METHODS

The authors reviewed a total of 256 patients who underwent single-segment PLIF at L4-5 for degenerative lumbar spondylolisthesis (DLS) and were followed up for at least 5 years. The definition of ASD was a symptomatic condition requiring an additional operation at the adjacent fusion segment in patients who had undergone PLIF. ASD occurring within 3 years after primary PLIF was categorized as early-onset ASD. As a control group, 54 age- and sex-matched patients who had not suffered from ASD for more than 10 years were selected from this series.

RESULTS

There were 42 patients with ASD at the final follow-up. ASD prevalence rates at 3, 5, and 10 years postoperatively and at the final follow-up were 5.0%, 8.2%, 14.1%, and 16.4%, respectively. With respect to ASD pathologies, lumbar disc herniation (LDH) was significantly more common in early-onset ASD, while lumbar spinal stenosis and DLS occurred more frequently in late-onset ASD. Significant differences were detected in the overall postoperative range of motion (ROM) and in the changes in ROM (ΔROM) at L3-4 (the cranial adjacent fusion segment) and changes in SL (ΔSL) at L4-5 (the fused segment), while there were no significant differences in other pre- and postoperative parameters. In stepwise logistic regression analysis, ΔSL was identified as an independent variable (p = 0.008) that demonstrated significant differences, especially in early-onset ASD (control 1.1° vs overall ASD -2.4°, p = 0.002; control 1.1° vs early-onset ASD -6.6°, p = 0.00004).

CONCLUSIONS

The study results indicated that LDH was significantly more common as a pathology in early-onset ASD and that ΔSL was a major risk factor for ASD, especially early-onset ASD.

Seasonal variation in incidence and causal organism of surgical site infection after PLIF/TLIF surgery: A multicenter study

BACKGROUND

Postoperative SSI is a common and potentially serious complication in spine surgery. Seasonal variation occurs in rates of nosocomial infection, with higher rates found in the summer, during which hot, humid conditions may be optimal for proliferation of bacteria. This might also influence the rate of SSI. The purpose of the study was to examine seasonal variation in SSI after PLIF/TLIF surgery, including relationships with experience of surgeons and causal organisms.

METHODS

Cases with SSI after PLIF/TLIF surgery at 10 facilities between January 1, 2012, and December 31, 2014 were retrieved from a database. Infection was defined based on CDC guidelines for SSIs. Patients were followed for at least two years after surgery. Surgeries were examined in spring (April-June), summer (July-September), autumn (October-December), and winter (January-March). Seasonal variation and other factors with a potential association with SSIs were evaluated.

RESULTS

A total of 1174 patients (607 males, 567 females) who underwent PLIF/TLIF surgery were identified. The operations were PLIF (n = 667), TLIF (n = 443), MIS-PLIF (n = 27), and MIS-TLIF (n = 37). The total SSI rate for the 2-year period was 2.5% (29/1174), and the 2-year average SSI rates for surgeries in each season were spring, 2.6% (7/266); summer, 3.9% (13/335); fall, 1.3% (4/302); winter, 1.8% (5/271). The SSI rate was significantly higher in summer than non-summer (3.9% vs. 1.9%, p < 0.05). SSIs were caused by a variety of pathogens, including Gram-positive cocci, and Staphylococcus aureus was the most common pathogenic organism to cause SSI.

CONCLUSION

Seasonality should be taken into account in strategies for SSI prevention, with particular attention on mitigation of increased temperature and humidity in the summer and on infection caused by Gram-positive cocci and S. aureus.

The comparison between anterior and posterior approaches for removal of infected lumbar interbody cages and a proposal regarding the use of endoscope-assisted technique

Background

In cases of postoperative deep wound infection after interbody fusion with cages, it is often difficult to decide whether to preserve or remove the cages, and there is no consensus on the optimal approach for removing cages. The aim of this study was to investigate the surgical management of cage infection after lumbar interbody fusion.

Methods

A retrospective study was conducted between January 2012 and August 2018. Patients were included if they had postoperative deep wound infection and required cage removal. Clinical outcomes, including operative parameters, visual analog scale, neurologic status, and fusion status, were assessed and compared between anterior and posterior approaches for cage removal.

Results

Of 130 patients who developed postoperative infection and required surgical debridement, 25 (27 levels) were diagnosed with cage infection. Twelve underwent an anterior approach, while 13 underwent cage removal with a posterior approach. Significant differences were observed between the anterior and posterior approaches in elapsed time to the diagnosis of cage infection, operative time, and hospital stay. All patients had better or stationary American Spinal Injury Association impairment scale, but one case of recurrence in adjacent disc 3 months after the surgery.

Conclusions

Both anterior and posterior approaches for cage removal, followed by interbody debridement and fusion with bone grafts, were feasible methods and offered promising results. An anterior approach often requires an additional extension of posterior instrumentation due to the high incidence of concurrent pedicle screw loosening. The use of an endoscope-assisted technique is suggested to facilitate safe removal of cages.

Should adjacent asymptomatic lumbar disc herniation be simultaneously rectified? A retrospective cohort study of 371 cases that received an open fusion or endoscopic discectomy only on symptomatic segments

BACKGROUND CONTEXT

In the treatment of multiple disc herniations, the decision of whether to include the presumed asymptomatic lumbar disc herniation (asLDH) at adjacent segments remains uncertain. On the one hand, the untouched asLDH might soon become symptomatic and require treatment. On the other hand, additional surgery involving more segments will introduce greater risk, complications, and cost.

PURPOSE

To investigate the prognosis of untreated asLDH after open fusion or percutaneous endoscopic lumbar discectomy (PELD) on symptomatic lumbar disc herniation (LDHs) in patients.

STUDY DESIGN

This is a retrospective cohort study.

PATIENT SAMPLE

A total of 371 patients with multiple disc herniations who underwent open discectomy and fusion or PELD only for symptomatic levels from January 2012 to July 2018 were included.

OUTCOME MEASURES

The primary outcome of interest was the development of symptomatic LDH at the previous asLDH of both groups that required reoperation. A second analysis was performed to compare the reoperation rate due to deterioration of asLDH among different severity grades of herniation. Reoperation rates of the original surgery at the symptomatic segment in both fusion and PELD groups were also reviewed.

METHODS

The patients were divided into two groups based on the surgical procedure, with 264 patients undergoing fusion surgery and 107 patients undergoing PELD. Clinical and imaging follow-ups were performed at routine intervals for more than 3 years. The reoperation rates due to deterioration of previously asLDH and failure of original surgery were investigated and compared between the two groups, as well as among the different severity grades of herniation.

RESULTS

The follow-up times were 48.2±24.2 and 41.1±17.5 months for the fusion and the PELD groups, respectively. The overall reoperation rate at the previous adjacent asLDH was 6.7% (25/317). According to the severity of the asLDH, a higher grade of asymptomatic herniation yielded a significantly higher rate of reoperation rate in both groups. If the nerve root was displaced by disc material prominently (nG2), the reoperation rate of asLDHs was 42.9% (3/7) in the fusion group and 20% (3/15) in the PELD group. Twenty out of 264 patients (7.6%) in the fusion group and 5 out of 107 patients (4.7%) in the PELD group required reoperation due to deterioration of asLDH. Reoperation rates due to failure of the original surgery were 7.6% (20/264) in the fusion group and 8.4% (9/107) in the PELD group.

CONCLUSIONS

With multilevel LDHs, if the asLDH is left untreated, the reoperation rate is closely related to the degree of herniation. When confronting an asLDH graded as G2, a high possibility of reoperation should be clearly discussed with the patient, regardless of open fusion or PELD techniques. Considering that fusion and minimally invasive nonfusion techniques did not yield significantly different overall reoperation rates, ongoing degeneration seemed to have a greater contribution in terms of the deterioration of asLDH.

Complications in TLIF spondylodesis-do they influence the outcome for patients? A prospective two-center study

PURPOSE

Transforaminal lumbar interbody fusion (TLIF) is a widely accepted surgical procedure for degenerative disk disease. While numerous studies have analyzed complication rates and risk factors this study investigates the extent to which complications after TLIF spondylodesis alter the clinical outcome regarding pain and physical function.

METHODS

A prospective clinical two-center study was conducted, including 157 patients undergoing TLIF spondylodesis with 12-month follow-up (FU). Our study classified complications into three subgroups: none (I), minor (IIa), and major complications (IIb). Complications were considered "major" if revision surgery was required or new permanent physical impairment ensued. Clinical outcome was assessed using visual analog scales for back (VAS-B) and leg pain (VAS-L), and Oswestry Disability Index (ODI).

RESULTS

Thirty-nine of 157 patients (24.8%) had at least one complication during follow-up. At FU, significant improvement was seen for group I (n = 118) in VAS-B (-50%), VAS-L (-54%), and ODI (-48%) and for group IIa (n = 27) in VAS-B (-40%), VAS-L (-64%), and ODI (-47%). In group IIb (n = 12), VAS-B (-22%, P = 0.089) and ODI (-33%, P = 0.056) improved not significantly, while VAS-L dropped significantly less (-32%, P = 0.013) compared to both other groups.

CONCLUSION

Our results suggest that major complications with need of revision surgery after TLIF spondylodesis lead to a significantly worse clinical outcome (VAS-B, VAS-L, and ODI) compared to no or minor complications. It is therefore vitally important to raise the surgeon´s awareness of consequences of major complications, and the topic should be given high priority in clinical work.

Incidental Durotomy Following Transforaminal Lumbar Interbody Fusion Performed with the Modified Wiltse Approach

PURPOSE

 Incidental durotomy is an intraoperative complication that occurs in 3 to 27% of lumbar spine surgeries. It has been reported more commonly following revision spinal procedures.

STUDY OBJECTIVES

 To investigate the frequency of incidental durotomy while performing transforaminal lumbar interbody fusion (TLIF) using the modified Wiltse approach. A secondary goal was to compare the incidence of durotomy in patients undergoing primary spine surgery with those undergoing revision surgery.

METHODS

 A group of consecutive patients who had undergone (TLIF) in the last 10 years ending in 2015 were enrolled in the study. All patients underwent TLIF via the modified Wiltse approach that included a central midline skin incision, followed by a paravertebral blunt dissection of the paraspinal muscles to reach the transverse processes. The deep paravertebral dissection was done conservatively, one side at a time. Demographic and clinical data were collected when relevant to the comparison.

RESULTS

 The study cohort encompassed 257 patients: 200 primary cases and 57 revisions. The frequency of incidental durotomy was equal in both groups: 3.5% each (7/200 and 2/57). All durotomies were repaired primarily. No other immediate or late complications were observed during follow-up.

CONCLUSION

 The present study displays a limited incidence of durotomy in the primary interventions and to a lesser degree in the revisions, all of which had used a TLIF performed with the modified Wiltse approach. This procedure probably circumvented the need for further revisions.

[Comparison of the effectiveness of oblique lumbar interbody fusion and posterior lumbar interbody fusion for treatment of Cage dislodgement after lumbar surgery]

OBJECTIVE

To compare the clinical and radiological effectiveness of oblique lumbar interbody fusion (OLIF) and posterior lumbar interbody fusion (PLIF) in the treatment of Cage dislodgement after lumbar surgery.

METHODS

The clinical data of 40 patients who underwent revision surgery due to Cage dislodgement after lumbar surgery betweem April 2013 and March 2017 were retrospectively analyzed. Among them, 18 patients underwent OLIF (OLIF group) and 22 patients underwent PLIF (PLIF group) for revision. There was no significant difference between the two groups in age, gender, body mass index, intervals between primary surgery and revision surgery, number of primary fused levels, disc spaces of Cage dislodgement, and visual analogue scale (VAS) scores of low back pain and leg pain, Oswestry disability index (ODI), the segmental lordosis (SL) and disc height (DH) of the disc space of Cage dislodgement, and the lumbar lordosis (LL) before revision ( P>0.05). The operation time, intraoperative blood loss, hospital stay, and complications of the two groups were recorded and compared. The VAS scores of low back pain and leg pain were evaluated at 3 days, 3, 6, and 12 months after operation, and the ODI scores were evaluated at 3, 6, and 12 months after operation. The SL and DH of the disc space of Cage dislodgement and LL were measured at 12 months after operation and compared with those before operation. CT examination was performed at 12 months after operation, and the fusion of the disc space implanted with new Cage was judged by Bridwell grading standard.

RESULTS

The intraoperative blood loss in the OLIF group was significantly less than that in the PLIF group ( t=-12.425, P=0.000); there was no significant difference between the two groups in the operation time and hospital stay ( P>0.05). Both groups were followed up 12-30 months, with an average of 18 months. In the OLIF group, 2 patients (11.1%) had thigh numbness and 1 patient (5.6%) had hip flexor weakness after operation; 2 patients (9.1%) in the PLIF group had intraoperative dural sac tear. The other patients' incisions healed by first intention without early postoperative complications. There was no significant difference in the incidence of complications between the two groups ( χ 2=0.519, P=0.642). The VAS scores of low back pain and leg pain, and the ODI score of the two groups at each time point after operation were significantly improved when compared with those before operation ( P<0.05); there was no significant difference between the two groups at each time point after operation ( P>0.05). At 12 months after operation, SL, LL, and DH in the two groups were significantly increased when compared with preoperative ones ( P<0.05); SL and DH in the OLIF group were significantly improved when compared with those in the PLIF group ( P<0.05), and there was no significant difference in LL between the two groups ( P>0.05). CT examination at 12 months after operation showed that all the operated disc spaces achieved bony fusion. According to the Bridwell grading standard, 12 cases were grade Ⅰ and 6 cases were grade Ⅱ in the OLIF group, and 13 cases were grade Ⅰ and 9 cases were grade Ⅱ in the PLIF group; there was no significant difference between the two groups ( Z=-0.486, P=0.627). During follow-up, neither re-displacement or sinking of Cage, nor loosening or fracture of internal fixation occurred.

CONCLUSION

OLIF and PLIF can achieve similar effectiveness in the treatment of Cage dislodgement after lumbar surgery. OLIF can further reduce intraoperative blood loss and restore the SL and DH of the disc space of Cage dislodgement better.

The Navigated Oblique Lumbar Interbody Fusion: Accuracy Rate, Effect on Surgical Time, and Complications

Objective

The oblique lumbar interbody fusion (OLIF) can be done with either fluoroscopy or navigation. However, it is unclear how navigation affects the overall flow of the procedure. We wished to report on the accuracy of this technique using navigation and on how navigation affects surgical time and complications.

Methods

A retrospective review was undertaken to evaluate patients who underwent OLIF using spinal navigation at University of California San Francisco. Data collected were demographic variables, perioperative variables, and radiographic images. Postoperative lateral radiographs were analyzed for accuracy of cage placement. The disc space was divided into 4 quadrants from anterior to posterior, zone 1 being anterior, and zone 4 being posterior. The accuracy of cage placement was assessed by placement.

Results

There were 214 patients who met the inclusion criteria. A total of 350 levels were instrumented from L1 to L5 using navigation. The mean follow-up time was 17.42 months. The mean surgical time was 211 minutes, and the average surgical time per level was 129.01 minutes. After radiographic analysis, 94.86% of cages were placed within quartiles 1 to 3. One patient (0.47%) underwent revision surgery because of suboptimal cage placement. For approach-related complications, transient neurological symptoms were 10.28%, there was no vascular injury.

Conclusion

The use of navigation to perform OLIF from L1 to L5 resulted in a cage placement accuracy rate of 94.86% in 214 patients.

IMPROVEMENT OF ODI AND SF-36 QUESTIONNAIRES SCORE AFTER ONE YEAR OF PLIF OR TLIF

ABSTRACT Objective: Determine if patients undergoing PLIF or TLIF surgery achieved improvement in the score of ODI and SF-36 questionnaires one year after surgery. Methods: Retrospective, single-center and non-randomized study. Patients submitted to spinal surgery using the PLIF or TLIF technique were included who completed the ODI and SF-36 questionnaires at least at the preoperative visit, and one year after surgery. Patients were divided into two groups, Group 1 (1 surgery level) and Group 2 (> 1 surgery level) and the ODI and SF-36 scores were compared for improvement. Results: The mean age was 47 years, with 52% of males (13/25) and mean of 5 days of hospital stay. Patients presented a significant improvement of ODI questionnaire (p<0.001) and in all SF-36 domains except in General Health State (p=0.58). In each group, it was observed that patients submitted to more than one level of surgery had greater blood loss and shorter hospital stay; however, the improvement obtained in ODI and SF-36 compared to the one-level surgery group was similar. Conclusions: PLIF and TLIF techniques are effective and lead to improved scores in ODI and SF-36 questionnaires one year after surgery. Patients undergoing two or more levels of instrumentation showed significant and similar improvement in ODI and SF-36. Level of evidence II, Single-Center Retrospective Study.

Factors Predictive of Adjacent Segment Disease After Lumbar Spinal Fusion

OBJECTIVE

Adjacent segment disease (ASD) is a long-term complication of lumbar spinal fusion. This study aims to evaluate demographic and operative factors that influence development of ASD after fusion for lumbar degenerative pathologies.

METHODS

A retrospective cohort study was performed on patients undergoing instrumented lumbar fusion for degenerative disorders (spondylolisthesis, stenosis, or intervertebral disk degeneration) with a minimum follow-up of 6 months.

RESULTS

Our inclusion criteria were met by 568 patients; 29.4% of patients had developed surgical ASD. Median follow-up was 2.8 years. Multivariate logistic regression analysis showed that decompression of segments outside the fusion construct had higher ASD (odds ratio = 2.6; P < 0.001), and those undergoing fusion for spondylolisthesis had lower ASD (odds ratio = 0.47; P = 0.003).

CONCLUSIONS

Results of our study show that the most important surgical factor contributing to ASD is decompression beyond fused levels. Hence caution should be exercised when decompressing spinal segments outside the fusion construct. Conversely, spondylolisthesis patients had the lowest ASD rates in our cohort.

Comparison of Nitinol and Titanium Nails Effectiveness for Lumbosacral Spine Fixation in Surgical Treatment of Degenerative Spine Diseases

Relevance. Surgical decompression and decompression with stabilization are highly effective for treatment of spinal canal stenosis at the level of lumbar spine. However, complications developing after application of rigid fixation systems resulted in active introduction of dynamic implants into clinical practice.

Purpose of the study — to compare effectiveness of nitinol and titanium nails for lumbosacral fixation in surgical treatment of degenerative spine diseases.

Materials and methods. 220 patients who underwent surgeries in 4 hospitals were randomized into two groups, each consisting of 110 patients (1:1 ratio): a group of patients who underwent stabilization of the vertebral motor segments with rods of nitinol with the required volume of decompression at the operation level and a group of patients who underwent stabilization of the vertebral motor segments with standard rods of titanium with the required volume of decompression at the intervention level. Patients suffered clinically significant spinal canal stenosis in one or two adjacent segments: from L3 to S1. Outcomes were evaluated during three years postoperatively by VAS scale for spine and lower limbs, and by ODI and SF-36 scales.

Results. All scales demonstrated better values in both groups of patients, namely, significant decrease of pain syndrome and improvement in mental and physical health. X-ray examination of all patients during the study period demonstrated restoration of lumbar lordosis. Group of patients with dynamic nails featured less complications rate related to metal implants including adjacent segment disease.

Conclusion. Transpedicular fixation of lumbosacral spine by nitinol nails is an effective technique allowing to preserve motion along with stable fixation.

Is minimally invasive superior than open transforaminal lumbar interbody fusion for single-level degenerative lumbar diseases: a meta-analysis

Background

In recent years, the minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) is increasingly used to manage the lumbar degenerative disease. However, whether MI-TLIF was superior than open transforaminal lumbar interbody fusion (O-TLIF) was controversial. The aim of this meta-analysis was to compare the clinical outcomes between the MI-TLIF and O-TLIF in single-level degenerative lumbar diseases.

Methods

Two reviewers independently searched EMBASE, PubMed, Web of Science, and Google database from inception to February 2018 for studies comparing the MI-TLIF and O-TLIF approach for single-level lumbar degenerative disease. The data were extracted and analyzed for primary outcomes such as total blood loss, visual analog score (VAS), and other secondary outcomes (length of hospital stay, operation time, fluroscopic time, and Oswestry Disability Index (ODI)). Meta-analysis was performed by Stata 12.0.

Results

Seven RCTs were finally included in this meta-analysis. Compared with O-TLIF, MI-TLIF was associated with significantly less blood loss (weighted mean difference (WMD) = − 291.46; 95% confidence interval (CI) − 366.66 to − 216.47; P = 0.000,). There was no significant difference between the length of hospital stay, postoperative VAS, and ODI. Compared with O-TLIF, MI-TLIF was associated with an increase of the fluroscopic time (P < 0.05).

Conclusion

The MI-TLIF showed significantly less blood loss compared with O-TLIF and more fluroscopic time. There was no significant difference between the length of hospital stay, postoperative VAS, and ODI. More high-quality studies and subsequent meta-analyses are needed in the future.