Overpowering posterior lumbar instrumentation and fusion with hyperlordotic anterior lumbar interbody cages followed by posterior revision: a preliminary feasibility study

Pedicle Subtraction Osteotomy Versus Multilevel Anterior Lumbar Interbody Fusion and Lateral Lumbar Interbody Fusion in the Treatment of Adult Spinal Deformity: Trends, Outcomes, and Cost

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

The aim of this study was to compare the outcomes of pedicle subtraction osteotomy (PSO) with multilevel anterior lumbar interbody fusion (ALIF) and lateral lumbar interbody fusion (LLIF) in posterior long-segment fusion.

BACKGROUND

PSO and ALIF/LLIF are 2 techniques used to restore lumbar lordosis and correct sagittal alignment, with each holding its unique advantages and disadvantages. As there are situations where both techniques can be employed, it is important to compare the risks and benefits of both.

PATIENTS AND METHODS

Patients aged 18 years or older who underwent PSO or multilevel ALIF/LLIF with posterior fusion of 7-12 levels and pelvic fixation were identified. 1:1 propensity score was used to match PSO and ALIF/LLIF cohorts for age, sex, and relevant comorbidities, including smoking status. Logistic regression was used to compare medical and surgical outcomes. Trends and costs were generated for both groups as well.

RESULTS

ALIF/LLIF utilization in posterior long fusion has been steadily increasing since 2010, whereas PSO utilization has significantly dropped since 2017. PSO was associated with an increased risk of durotomy ( P < 0.001) and neurological injury ( P = 0.018). ALIF/LLIF was associated with increased rates of postoperative radiculopathy ( P = 0.005). Patients who underwent PSO had higher rates of pseudarthrosis within 1 and 2 years ( P = 0.015; P = 0.010), 1-year hardware failure ( P = 0.028), and 2-year reinsertion of instrumentation ( P = 0.009). Reoperation rates for both approaches were not statistically different at any time point throughout the 5-year period. In addition, there were no significant differences in both procedural and 90-day postoperative costs.

CONCLUSIONS

PSO was associated with higher rates of surgical complications compared with anterior approaches. However, there was no significant difference in overall reoperation rates. Spine surgeons should select the optimal technique for a given patient and the type of lordotic correction required.

Advances in Anterolateral Approaches to the Lumbar Spine: A Focus on Technological Developments

A historical overview of the evolution of anterolateral approaches to the lumber spine and associated patient outcomes is presented. In addition, the modern incorporation of new technologies is discussed, including interbody cages, intraoperative image guidance, robotics, augmented reality, and machine learning, which have significantly improved the spine surgery safety and efficacy profile. Current challenges and future directions are also covered, emphasizing the need for further research and development, particularly in robotic assistance and machine learning algorithms.

Anterior Column Realignment Through Open Pre-posterior Release-Anterior-Posterior Fusion Versus Hybrid Minimally Invasive-Anterior-Posterior Fusion for Dynamic Sagittal Imbalance of the Spine

STUDY DESIGN

Retrospective comparative study.

OBJECTIVES

To investigate the clinical and radiological outcomes after anterior column realignment (ACR) through pre-posterior release-anterior-posterior surgery (PAP) and minimally invasive surgery -lateral lumbar interbody fusion (MIS-LLIF) using hybrid anterior-posterior surgery (AP).

METHODS

A total of 91 patients who underwent ACR with long fusions from T10 vertebra to the sacropelvis with a follow-up period of at least 2 years after corrective surgery for adult spinal deformity were included and divided into two groups by surgical method: AP and PAP. AP was performed in 26 and PAP in 65 patients. Clinical outcomes and radiological parameters were investigated and compared. A further comparison was conducted after propensity score matching between the groups.

RESULTS

The more increase of LL and decrease of PI-LL mismatch were observed in the PAP group than in the AP group postoperatively. After propensity score matching, total operation time and intraoperative bleeding were greater, and intensive care unit care and rod fracture were more frequent in the PAP group than in the AP group with statistical significance. Reoperation rate was higher in PAP (29.2%) than in AP (16.7%) without statistical significance.

CONCLUSIONS

PAP provides a more powerful correction for severe sagittal malalignment than AP procedures. AP results in less intraoperative bleeding, operation time, and postoperative complications. Therefore, this study does not suggest that one treatment is superior to the other.

LEVEL OF EVIDENCE

III.

Three-Column Osteotomy in Adult Spinal Deformity: An Analysis of Temporal Trends in Usage and Outcomes

BACKGROUND

Three-column osteotomies (3COs), usually in the form of pedicle subtraction or vertebral column resection, have become common in adult spinal deformity surgery. Although a powerful tool for deformity correction, 3COs can increase the risks of perioperative morbidity.

METHODS

Operative patients with adult spinal deformity (Cobb angle of >20°, sagittal vertical axis [SVA] of >5 cm, pelvic tilt of >25°, and/or thoracic kyphosis of >60°) with available baseline and 2-year radiographic and health-related quality-of-life (HRQoL) data were included. Patients were stratified into 2 groups by surgical year: Group I (2008 to 2013) and Group II (2014 to 2018). Patients with 3COs were then isolated for outcomes analysis. Severe sagittal deformity was defined by an SVA of >9.5 cm. Best clinical outcome (BCO) was defined as an Oswestry Disability Index (ODI) of <15 and Scoliosis Research Society (SRS)-22 of >4.5. Multivariable regression analyses were used to assess differences in surgical, radiographic, and clinical parameters.

RESULTS

Seven hundred and fifty-two patients with adult spinal deformity met the inclusion criteria, and 138 patients underwent a 3CO. Controlling for baseline SVA, PI-LL (pelvic incidence minus lumbar lordosis), revision status, age, and Charlson Comorbidity Index (CCI), Group II was less likely than Group I to have a 3CO (21% versus 31%; odds ratio [OR] = 0.6; 95% confidence interval [CI] = 0.4 to 0.97) and more likely to have an anterior lumbar interbody fusion (ALIF; OR = 1.6; 95% CI = 1.3 to 2.3) and a lateral lumbar interbody fusion (LLIF; OR = 3.8; 95% CI = 2.3 to 6.2). Adjusted analyses showed that Group II had a higher likelihood of supplemental rod usage (OR = 21.8; 95% CI = 7.8 to 61) and a lower likelihood of proximal junctional failure (PJF; OR = 0.23; 95% CI = 0.07 to 0.76) and overall hardware complications by 2 years (OR = 0.28; 95% CI = 0.1 to 0.8). In an adjusted analysis, Group II had a higher likelihood of titanium rod usage (OR = 2.7; 95% CI = 1.03 to 7.2). Group II had a lower 2-year ODI and higher scores on Short Form (SF)-36 components and SRS-22 total (p < 0.05 for all). Controlling for baseline ODI, Group II was more likely to reach the BCO for the ODI (OR = 2.8; 95% CI = 1.2 to 6.4) and the SRS-22 total score (OR = 4.6; 95% CI = 1.3 to 16).

CONCLUSIONS

Over a 10-year period, the rates of 3CO usage declined, including in cases of severe deformity, with an increase in the usage of PJF prophylaxis. A better understanding of the utility of 3CO, along with a greater implementation of preventive measures, has led to a decrease in complications and PJF and a significant improvement in patient-reported outcome measures.

LEVEL OF EVIDENCE

Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Utilization of lateral anterior lumbar interbody fusion for revision of failed prior TLIF: illustrative case

BACKGROUND

The use of the lateral decubitus approach for L5–S1 anterior lumbar interbody fusion (LALIF) is a recent advancement capable of facilitating single-position surgery, revision operations, and anterior column reconstruction. To the authors’ knowledge, this is the first description of the use of LALIF at L5–S1 for failed prior transforaminal lumbar interbody fusion (TLIF) and anterior column reconstruction. Using an illustrative case, the authors discuss their experience using LALIF at L5–S1 for the revision of pseudoarthrosis and TLIF failure.

OBSERVATIONS

The patient had prior attempted L2 to S1 fusion with TLIF but suffered from hardware failure and pseudoarthrosis at the L5–S1 level. LALIF was used to facilitate same-position revision at L5–S1 in addition to further anterior column revision and reconstruction by lateral lumbar interbody fusion at the L1–2 level. Robotic posterior T10–S2 fusion was then added to provide stability to the construct and address the patient’s scoliotic deformity. No complications were noted, and the patient was followed until 1 year after the operation with a favorable clinical and radiological result.

LESSONS

Revision of a prior failed L5–S1 TLIF with an LALIF approach has technical challenges but may be advantageous for single position anterior column reconstruction under certain conditions.

Successful salvage strategy using anterior retroperitoneal approach in failed posterior lumbar interbody fusion. A retrospective analisys on lumbar lordosis and clinical outcome

OBJECTIVE

Posterior and transforaminal lumbar interbody fusion (PLIF, TLIF) are among the most popular surgical options for lumbar interbody fusion. If non-union occurs with consequent pain and reduced quality of life, revision surgery should correct any previous technical errors, avoiding further complications. The aim of this study was to analyze technical advantages, radiological and clinical outcomes of anterior approaches (ALIF) in case of failed PLIF or TLIF.

METHODS

Retrospective analysis of consecutive patients with persistent low back pain after failed PLIF/TLIF where salvage ALIF through an anterior retroperitoneal miniopen video-assisted technique was performed. Surgical, clinical and radiological data were analysed. Uni and multivariate statistical analysis were applied.

RESULTS

Thirty-six patients (average age: 47.1 years) were included. Mean follow-up was 34.4 months. In 30 patients (83.3%) a posterior surgical step was necessary. Non-union (86.1%), cage migration (5.5%), infection (8.3%) were the causes of revision surgery. In 22 patients (61.1%) the involved level was L5-S1, in 12 patients (33.4%) L4-L5, in 1 patient (2.7%) L3-L4. One patient (2.7%) had two levels (L4-L5 and L5-S1) involved. No major intraoperative complications were recorded. Significant correlation between clinical and radiological outcomes (L4-S1 and L5-S1 lordosis improvement) were observed (postoperative VAS and L5-S1, p = 0.038).

CONCLUSIONS

Salvage ALIF is a safe option that can significantly ameliorate residual pain achieving primary interbody stability with an ideal segmental lordosis according to pelvic parameters. The advantages of a naive anterior approach fulfils the main objectives of a revision surgery in order to significantly increase the chances of definitive fusion.

Radiographic comparison of lordotic and hyperlordotic implants in L5-S1 anterior lumbar interbody fusion

OBJECTIVE

Anterior lumbar interbody fusion (ALIF) used at the lumbosacral junction provides arthrodesis for several indications. The anterior approach allows restoration of lumbar lordosis, an important goal of surgery. With hyperlordotic ALIF implants, several options may be employed to obtain the desired amount of lordosis. In this study, the authors compared the degree of radiographic lordosis achieved with lordotic and hyperlordotic ALIF implants at the L5-S1 segment.

METHODS

All patients undergoing L5-S1 ALIF from 2 institutions over a 4-year interval were included. Patients < 18 years of age or those with any posterior decompression or osteotomy were excluded. ALIF implants in the lordotic group had 8° or 12° of inherent lordosis, whereas implants in the hyperlordotic group had 20° or 30° of lordosis. Upright standing radiographs were used to determine all radiographic parameters, including lumbar lordosis, segmental lordosis, disc space lordosis, and disc space height. Separate analyses were performed for patients who underwent single-segment fixation at L5-S1 and for the overall cohort.

RESULTS

A total of 204 patients were included (hyperlordotic group, 93 [45.6%]; lordotic group, 111 [54.4%]). Single-segment ALIF at L5-S1 was performed in 74 patients (hyperlordotic group, 27 [36.5%]; lordotic group, 47 [63.5%]). The overall mean ± SD age was 61.9 ± 12.3 years; 58.3% of patients (n = 119) were women. The mean number of total segments fused was 3.2 ± 2.6. Overall, 66.7% (n = 136) of patients had supine surgery and 33.3% (n = 68) had lateral surgery. Supine positioning was significantly more common in the hyperlordotic group than in the lordotic group (83.9% [78/93] vs 52.3% [58/111], p < 0.001). After adjusting for differences in surgical positioning, the change in lumbar lordosis was significantly greater for hyperlordotic versus lordotic implants (3.6° ± 7.5° vs 0.4° ± 7.5°, p = 0.048) in patients with single-level fusion. For patients receiving hyperlordotic versus lordotic implants, changes were also significantly greater for segmental lordosis (12.4° ± 7.5° vs 8.4° ± 4.9°, p = 0.03) and disc space lordosis (15.3° ± 5.4° vs 9.3° ± 5.8°, p < 0.001) after single-level fusion at L5-S1. The change in disc space height was similar for these 2 groups (p = 0.23).

CONCLUSIONS

Hyperlordotic implants provided a greater degree of overall lumbar lordosis restoration as well as L5-S1 segmental and disc space lordosis restoration than lordotic implants. The change in disc space height was similar. Differences in lateral and supine positioning did not affect these parameters.

Pseudarthrosis and Rod Fracture Rates After Transforaminal Lumbar Interbody Fusion at the Caudal Levels of Long Constructs for Adult Spinal Deformity Surgery

BACKGROUND

Interbody fusion at the caudal levels of long constructs for adult spinal deformity (ASD) surgery is used to promote fusion and secure a solid foundation for maintenance of deformity correction. We sought to evaluate long-term pseudarthrosis, rod fracture, and revision rates for TLIF performed at the base of a long construct for ASD.

METHODS

We reviewed 316 patients who underwent TLIF as a component of ASD surgery for medical comorbidities, surgical characteristics, and rate of unplanned reoperation for pseudarthrosis or instrumentation failure at the TLIF level. Fusion grading was assessed after revision surgery for pseudarthrosis at the TLIF level.

RESULTS

Rate of pseudarthrosis at the TLIF level was 9.8% (31/316), and rate of rod fractures was 7.9% (25/316). The rate of revision surgery at the TLIF level was 8.9% (28/316), and surgery was performed at a mean of 20.4 ± 16 months from the index procedure. Current smoking status (odds ratio 3.34, P = 0.037) was predictive of pseudarthrosis at the TLIF site. At a mean follow-up of 43 ± 12 months after revision surgery, all patients had achieved bony union at the TLIF site.

CONCLUSIONS

At 3-year follow-up, the rate of pseudarthrosis after TLIF performed at the base of a long fusion for ASD was 9.8%, and the rate of revision surgery to address pseudarthrosis and/or rod fracture was 8.9%. All patients were successfully treated with revision interbody fusion or posterior augmentation of the fusion mass, without need for further revision procedures at the TLIF level.

Does interbody cage lordosis impact actual segmental lordosis achieved in minimally invasive lumbar spine fusion?

OBJECTIVE

In an effort to prevent loss of segmental lordosis (SL) with minimally invasive interbody fusions, manufacturers have increased the amount of lordosis that is built into interbody cages. However, the relationship between cage lordotic angle and actual SL achieved intraoperatively remains unclear. The purpose of this study was to determine if the lordotic angle manufactured into an interbody cage impacts the change in SL during minimally invasive surgery (MIS) for lumbar interbody fusion (LIF) done for degenerative pathology.

METHODS

The authors performed a retrospective review of a single-surgeon database of adult patients who underwent primary LIF between April 2017 and December 2018. Procedures were performed for 1-2-level lumbar degenerative disease using contemporary MIS techniques, including transforaminal LIF (TLIF), lateral LIF (LLIF), and anterior LIF (ALIF). Surgical levels were classified on lateral radiographs based on the cage lordotic angle (6°-8°, 10°-12°, and 15°-20°) and the position of the cage in the disc space (anterior vs posterior). Change in SL was the primary outcome of interest. Subgroup analyses of the cage lordotic angle within each surgical approach were also conducted.

RESULTS

A total of 116 surgical levels in 98 patients were included. Surgical approaches included TLIF (56.1%), LLIF (32.7%), and ALIF (11.2%). There were no differences in SL gained by cage lordotic angle (2.7° SL gain with 6°-8° cages, 1.6° with 10°-12° cages, and 3.4° with 15°-20° cages, p = 0.581). Subgroup analysis of LLIF showed increased SL with 15° cages only (p = 0.002). The change in SL was highest after ALIF (average increase 9.8° in SL vs 1.8° in TLIF vs 1.8° in LLIF, p < 0.001). Anterior position of the cage in the disc space was also associated with a significantly greater gain in SL (4.2° vs -0.3°, p = 0.001), and was the only factor independently correlated with SL gain (p = 0.016).

CONCLUSIONS

Compared with cage lordotic angle, cage position and approach play larger roles in the generation of SL in 1-2-level MIS for lumbar degenerative disease.

Anterior Lumbar Interbody Fusion (ALIF) L5-S1 with overpowering of posterior lumbosacral instrumentation and fusion mass: a reliable solution in revision spine surgery

BACKGROUND AND PURPOSE

In cases of spine surgical revisions of patients affected by sagittal malalignment, the restoration of the ideal lumbar lordosis (LL) is mandatory. ALIF procedures represent a powerful and effective approach to improve the LL in case of hypolordosis. This study evaluates the feasibility of ALIF to overpower posterior lumbar instrumentation and fusion mass in revision spine surgery and secondarily to estimate complications, clinical and radiological outcomes.

METHODS

This is a single-center retrospective analysis of prospectively collected data on the use of ALIF overpowering in cases of lumbosacral instrumentation and/or fusion. Demographic, comorbidity, corrective strategy adopted, surgical data, clinical and radiological results, and intraoperative and postoperative complications were recorded.

RESULTS

Twelve patients (3 male; 9 female) underwent overpowering ALIF L5-S1 were included in the study with a mean FU of 34.0 ± 13.4 months. In 10 cases, a posterior titanium instrumentation and fusion mass were present; in 2 patients, only a fusion mass was present. Indicators of pain and disability improved in all patients (p < 0.01). Sagittal realignment with the restoration of ideal spinopelvic parameters was obtained in all cases. One peritoneal lesion requiring intraoperative suture without sequelae, two cases of postoperative radiculopathy, and one posterior wound infection requiring surgical debridement and antibiotic therapy were reported.

CONCLUSIONS

Anterior implant of lordotic and hyperlordotic cages with increasing segmental lordosis is possible in the presence of posterior instrumentation and/or solid fusion mass. The biomechanical strength of this corrective technique can overcome posterior instrumentation and bone fusion resistance, therefore allowing a single-staged surgery for sagittal realignment.

Anterior Lumbar Interbody Fusion With Cage Retrieval for the Treatment of Pseudarthrosis After Transforaminal Lumbar Interbody Fusion: A Single-Institution Case Series

BACKGROUND

The treatment of pseudarthrosis after transforaminal lumbar interbody fusion (TLIF) can be challenging, particularly when anterior column reconstruction is required. There are limited data on TLIF cage removal through an anterior approach.

OBJECTIVE

To assess the safety and efficacy of anterior lumbar interbody fusion (ALIF) as a treatment for pseudarthrosis after TLIF.

METHODS

ALIFs performed at a single academic medical center were reviewed to identify cases performed for the treatment of pseudarthrosis after TLIF. Patient demographics, surgical characteristics, perioperative complications, and 1-yr radiographic data were collected.

RESULTS

A total of 84 patients were identified with mean age of 59 yr and 37 women (44.0%). A total of 16 patients (19.0%) underwent removal of 2 interbody cages for a total of 99 implants removed with distribution as follows: 1 L2/3 (0.9%), 6 L3/4 (5.7%), 37 L4/5 (41.5%), and 55 L5/S1 (51.9%). There were 2 intraoperative venous injuries (2.4%) and postoperative complications were as follows: 7 ileus (8.3%), 5 wound-related (6.0%), 1 rectus hematoma (1.1%), and 12 medical complications (14.3%), including 6 pulmonary (7.1%), 3 cardiac (3.6%), and 6 urinary tract infections (7.1%). Among 58 patients with at least 1-yr follow-up, 56 (96.6%) had solid fusion. There were 5 cases of subsidence (6.0%), none of which required surgical revision. Two patients (2.4%) required additional surgery at the level of ALIF for pseudarthrosis.

CONCLUSION

ALIF is a safe and effective technique for the treatment of TLIF cage pseudarthrosis with a favorable risk profile.

ALIF in the correction of spinal sagittal misalignment. A systematic review of literature

PURPOSE

We aim at analysing the impact of anterior lumbar interbody fusion (ALIF) in restoring the main spinopelvic parameters, along with its potentials and limitations in correcting sagittal imbalance.

MATERIALS AND METHODS

The 2009 PRISMA flow chart was used to systematically review the literature; 27 papers were eventually selected. The following spinopelvic parameters were observed: pelvic tilt (PT), sacral slope (SS), lumbar lordosis (LL), segmental lumbar lordosis (LLseg) and sagittal vertical axis (SVA). Papers reporting on hyperlordotic cages (HLC) were analysed separately. The indirect decompression potential of ALIF was also assessed. The clinical outcome was obtained by collecting visual analogue scale (VAS) for back and leg pain and Oswestry Disability Index (ODI) scores. Global fusion rate and main complications were collected.

RESULTS

PT, SS, LL, LLseg and SVA spinopelvic parameters all improved postoperatively by - 4.3 ± 5.2°, 3.9 ± 4.5°, 10.6 ± 12.5°, 6.7 ± 3.5° and 51.1 ± 44.8 mm, respectively. HLC were statistically more effective in restoring LL and LLseg (p < 0.05). Postoperative disc height, anterior disc height, posterior disc height and foraminal height, respectively, increased by 58.5%, 87.2%, 80.9% and 18.1%. Postoperative improvements were observed in VAS back and leg and ODI scores (p < 0.05). The global fusion rate was 94.5 ± 5.5%; the overall complication rate was 13%.

CONCLUSION

When managing sagittal imbalance, ALIF can be considered as a valid technique to achieve the correct spinopelvic parameters based on preoperative planning. This technique permits to obtain an optimal LL distribution and a solid anterior column support, with lower complications and higher fusion rates when compared to posterior osteotomies.

Surgical Strategies for the Treatment of Lumbar Pseudarthrosis in Degenerative Spine Surgery: A Literature Review and Case Study

BACKGROUND

Pseudarthrosis after lumbar fusion can generate pain and disability and often requires revision. However, results of revision procedures have historically been relatively poor.

QUESTIONS/PURPOSE

The aim of this review was to examine the current evidence related to the management of lumbar pseudarthrosis, with a focus on revision after failure of posterolateral fusion or lumbar interbody fusion.

METHODS

A review of orthopedic spine literature published before March 2019 was conducted using PubMed and Google Scholar. Studies addressing revision after failed posterolateral fusions and after failed interbody fusion were selected. We also present a case of successful revision after failed transforaminal lumbar interbody fusion (TLIF).

RESULTS

The review revealed that persistent pseudarthrosis after revision posterolateral fusion occurs at rates of 35 to 51%. No significant difference has been demonstrated in rates of successful fusion after anterior lumbar interbody fusion (ALIF) and ALIF with revision posterolateral fusion for pseudarthroses after failed TLIF procedures (81% versus 88%), although ALIF alone may be appealing because it avoids further disruption of the posterior musculature. No significant differences have been observed in quality-of-life scores among patients undergoing revision after posterolateral fusion, TLIF, ALIF, or ALIF with posterior fusion. Failed TLIF cages may be extracted and replaced through an anterior or lateral approach. If the geometry of the failed cage permits insertion of a second cage, a contralateral approach may be used. Revision retroperitoneal approaches are associated with higher complication rates.

CONCLUSIONS

The management of lumbar pseudarthrosis requires careful planning, as well as intra-operative attention to detail, for revision surgery to be successful. Circumferential procedures have shown success in revision posterolateral and interbody fusion failures.

[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.

Surgical Treatment of Flat Back Syndrome With Anterior Hyperlordotic Cages

BACKGROUND

Traditional correction for flat back syndrome is performed with a posterior-based surgery or combined approaches in revision cases.

OBJECTIVE

To evaluate outcome from anterior surgery with the use of hyperlordotic cages (HLCs) in patients with flat back syndrome.

METHODS

All patients operated with or without prior posterior lumbar surgery were studied. Pre- to postoperative sagittal alignment was analyzed. Radiographic parameters were analyzed including T1 pelvic angle (T1PA), sagittal vertical axis (SVA), pelvic tilt (PT), pelvic incidence (PI), lumbar lordosis (LL), sacral slope (SS), pelvic incidence and lumbar lordosis (PI-LL), and T4-12TK.

RESULTS

All 50 patients (mean age of 58 yr, 72% female with mean body mass index of 28) demonstrated significant radiographic alignment difference in their spinopelvic and global parameters from pre- to postoperative standing: LL (-37.04° vs -59.55°, P < .001), SS (35.12 vs 41.13, P < .001), PI-LL (23.55 vs 6.46), T4-12 TK (30.59 vs 41.67), PT (28.22 vs 22.13), SVA in mm (80.94 vs 37.39), and T1PA (28.70° vs 18.43°, P < .001). Using linear regression analysis, predicted pre- to postoperative change in standing LL corresponded to a pre- to postoperative changes in standing PI-LL mismatch, T1PA, TK, SS, PT, and SVA (R2 = 0.59, 0.38, 0.25, 0.16, 0.12, and 0.17, respectively). Five degrees of pre- to postoperative change in T1PA translates to -4.15° change in LL.

CONCLUSION

Anterior surgery with HLCs followed by posterior instrumentation is an effective technique to treat flat back syndrome. HLCs are effective to maximize LL up to 30°, which is equivalent in magnitude to a pedicle subtraction osteotomy, but associated with less blood loss, quicker recovery, lower complications, and good surgical outcome.

Revision surgery for non-union in adult spinal deformity

As adult spinal deformity surgery is performed more and more, the spine surgeon is faced with the challenge to treat pseudoarthrosis. The presentation may vary, from asymptomatic patients, who should be observed in most of the cases, to patients with acute episode of broken rods, and or chronic pain with often trunk imbalance. In some instances, patients will present with neurologic symptoms. The evaluation of such patients must start with a good understanding of why the surgery failed first place. Poor host, smoking, lack of anterior column support, poor sagittal balance, lack of fusion, poor construct. Often a combination of all of the above is encountered. The workup for such cases consists of imaging studies (with often a CT myelogram as the excessive metal artifact will render the MRI imaging useless), nutrition labs, DEXA scan, EOS films and internal medicine or cardiology consult for risk stratification as this may represent major surgery. Indication of surgery is mostly based on pain and imbalance and/or poor function. The surgeon planning a revision adult deformity surgery has many tasks to perform: Identify and avoid the reasons that lead to failure of the previous surgeries. Plan the anterior column reconstruction either through posterior or anterior interbody fusion. Restore the global alignment through anterior or posterior osteotomies to achieve sagittal and coronal balance. Obtain a solid fixation with sufficient levels above and below the osteotomies sites with in some cases the use of pelvic screws and four rods (Quad-Rod) techniques. The use of bone graft (either autologous, allograft, bone graft enhancers and inducer) agents. The requirement of decompression either through a virgin spine or a previous laminectomy bed. Despite the extent of these surgeries and the potential for immediate postoperative complications, the outcome is in most cases satisfactory if these goals are achieved. In this review, the authors explore different scenarios for pseudoarthrosis in the adult spine deformity patient and the preferred treatment method to obtain the best outcome for every individual patient. These slides can be retrieved under Electronic Supplementary Material.

Changes in Sagittal Alignment Following Short-Level Lumbar Interbody Fusion: Comparison between Posterior and Lateral Lumbar Interbody Fusions

Study Design

Retrospective case-control study.

Purpose

We aimed to compare radiologic outcomes between posterior (PLIF) and lateral lumbar interbody fusion (LLIF) in short-level spinal fusion surgeries.

Overview of Literature

Although LLIF enables surgeons to insert large lordotic cages, it is unknown whether LLIF more effectively corrects local and global sagittal alignments compared with PLIF in short-level spinal fusion surgeries.

Methods

Radiographic data acquired from patients with lumbar interbody fusion (≤3 levels) using PLIF or LLIF for degenerative lumbar diseases were analyzed. The following radiographic parameters were evaluated preoperatively and at 2 years postoperatively: segmental lordotic angle, disk height, lumbar lordosis (LL), pelvic tilt (PT), C7 sagittal vertical axis, and thoracic kyphosis (TK).

Results

In total, 144 patients with PLIF (193 fused levels) and 101 with LLIF (159 fused levels) were included. Patients’ backgrounds and preoperative radiographic parameters for any level of fusion did not differ significantly between PLIF and LLIF procedures. The LLIF group exhibited significantly greater changes at 1-level fusion compared to the PLIF group in the parameters of segmental lordotic angle (5.1°±5.8° vs. 2.1°±5.0°, p<0.001), disk height (4.2±2.3 mm vs. 2.2±2.0 mm, p<0.001), LL (7.8°±7.6° vs. 3.9°±8.6°, p=0.004), and PI–LL (−6.9°±6.8° vs. −3.6°±10.1°, p=0.03). While, a similar trend was observed regarding 2-level fusion, significantly greater changes were only observed in LL (12.1°±11.1° vs. 4.2°±9.1°, p=0.047) and PI–LL (−11.2°±11.3° vs. −3.0°±9.3°, p=0.043), PT (−6.4°±4.9° vs. −2.5°±5.3°, p=0.049) and TK (7.8°±11.8° vs. −0.3°±9.7°, p=0.047) in the LLIF group at 3-level fusion.

Conclusions

LLIF provides significantly better local sagittal alignment than PLIF in 1- or 2-level fusion cases and improves spinopelvic alignment and local alignment for 3-level fusion cases. Thus, LLIF was demonstrated to be a useful lumbar interbody fusion technique, constituting a powerful tool for achieving sagittal realignment with minimal surgical invasiveness.

Technical Consideration for TLIF Cage Retrieval and Deformity Correction With Anterior Interbody Fusion in Lumbar Revision Surgeries

INTRODUCTION

Symptomatic pseudoarthrosis after transforaminal lumbar interbody fusion (TLIF) could result in sagittal malalignment. Revision posterior surgery with TLIF cage removal poses a challenge intraoperatively. The authors have proposed salvage anterior approach for cage removal and have discussed unique experience with the correction in their deformity patients.

METHODS

All patients with symptoms of clinical deformity or symptomatic pseudoarthrosis operated from January of 2012 to February of 2018 were included in the study. TLIF cage removal followed by anterior lumbar interbody fusion (ALIF) surgery was performed in all patients. Radiographic sagittal parameters including thoracic kyphosis (TK; T4-T12), sagittal vertical axis (SVA), T1 pelvic angle (TPA), lumbar lordosis (LL), the mismatch between pelvic incidence (PI) and LL (PI-LL), sacral slope (SS), pelvic tilt (PT), and PI were analyzed.

RESULTS

6 patients (mean age of 57 years, 83% female) underwent TLIF retrieval through anterior approach and ALIF with hyperlordotic cages (HLCs), followed by posterior spinal fusion surgery. Described technique entails use of tailored instruments with sequential gentle distraction of end plates with TLIF spreader could facilitate in the cage removal. Mean number of interbody levels fused pre as well as post were 1.5. The radiographic sagittal parameters from preoperative versus postoperative standing were as follows: T4-T12 TK, 16° vs. 37.6°; LL, -25° vs. -47.6°; PT, 36° vs. 26°; PI-LL, 35° vs. 12.4°; SVA, 12° vs. 5.6°; and TPA, 44° vs. 25°, with p<.001. Mean number of instrumented level fused were 8.1. Using linear regression analysis, change from pre-to postoperative standing in LL predicted pre-to postoperative change in SVA and TPA for global correction (R= -0.30 and -0.80, respectively).

CONCLUSIONS

Anterior approach is a suitable technique for TLIF cage removal while preserving the end plates for subsequent optimal interbody fusion at the index level in symptomatic pseudoarthrosis patients or those with clinical deformity. ALIF with HLCs with or without Ponte osteotomy can restore segmental and overall sagittal alignment.

Overpowering the Previously Posterior Instrumented Cervical Spine With Cage-Assisted Anterior Cervical Discectomy and Fusion: A Cadaveric Study

PURPOSE

Cervical spines previously posteriorly instrumented and fused with a kyphotic deformity represent a surgical challenge. Current treatment strategies include C7 pedicle subtraction osteotomy or a posterior-anterior-posterior approach, which carry the risk of significant complications. The objective of this study was to attempt to achieve lordosis with multiple anterior cervical discectomy and fusion (ACDF) cages to overpower the posterior instrumentation.

METHODS

Four adult cadaveric specimens were selected and underwent C3-C7 posterior laminectomy with posterior instrumentation in a kyphotic alignment using a 3.5-mm titanium screw-rod system. Next, ACDF from C3 to C7 was performed with 15° lordotic cages to restore cervical lordosis. Posterior instrumentation was then inspected for failure. Fluoroscopic images were obtained to calculate total construct lordosis and change in segmental lordosis. CT scans were obtained after ACDF to assess for loosening, instrumentation failure, endplate damage, or impaction. Bone mineral density was calculated on CT scans.

RESULTS

Age ranged from 59 to 82, and all specimens were male. No gross instrumentation failure was observed. Mean pre-ACDF lordosis between C3 and C7 was 0° (-5° to 5°). Post-ACDF lordosis increased to 37° (35°-38°). Mean segmental lordosis achieved with no endplate destruction was 13.1° (8°-17°). T scores for the cadavers were -0.5, -0.5, -3.2, and -5.1. Two levels of impaction were observed (12.5%). Failure of bone screw interface occurred in the cadaver, with a T score of -5.1 in the middle of the construct.

CONCLUSION

Our study demonstrates the validity of overpowering posterior instrumentation through multiple level ACDF with lordotic cages. This may obviate the need to perform posterior-anterior-posterior procedures.

LEVEL OF EVIDENCE

Level III.

Approach Selection: Multiple Anterior Lumbar Interbody Fusion to Recreate Lumbar Lordosis Versus Pedicle Subtraction Osteotomy: When, Why, How?

Restoration of physiologic lumbar lordosis is a fundamental principle of spinal deformity surgery. Techniques using multilevel anterior lumbar interbody fusion or pedicle subtraction osteotomy (PSO) are described. Multilevel anterior lumbar interbody fusion provides a gradual multilevel correction and avoids the morbidity associated with PSO but necessitates familiarity with the anterior approach or an approach surgeon. PSO provides a large angular correction at a single level, requires only one approach, and allows for simultaneous multiplanar correction and open posterior decompression. This article provides guidance on the appropriate use of each technique for restoration of lumbar lordosis in patients with degenerative lumbar deformity.

A UK-based pilot study of current surgical practice and implant preferences in lumbar fusion surgery

Lumbar fusion surgery is an established procedure for the treatment of low back pain. Despite the wide set of alternative fusion techniques and existing devices, uniform guidelines are not available yet and common surgical trends are scarcely investigated.The purpose of this UK-based study was to provide a descriptive portrait of current surgeons' practice and implant preferences in lumbar fusion surgery.A UK-based in-person survey was designed for this study and submitted to a group of consultant spinal surgeons (n = 32). Fifteeen queries were addressed based on different aspects of surgeons' practice: lumbar fusion techniques, implant preferences, and bone grafting procedures. Answers were analyzed by means of descriptive statistics.Thirty-two consultant spinal surgeons completed the survey. There was clear consistency on the relevance of a patient-centered management (82.3%), along with a considerable variability of practice on the preferred fusion approach. Fixation surgery was found to be largely adopted (96.0%) and favored over stand-alone cages. With regards to the materials, titanium cages were the most used (54.3%). The geometry of the implants influenced the choice of lumbar cages (81.3%). Specifically, parallel-shape cages were mostly avoided (89.2%) and hyperlordotic cages were preferred at the lower lumbar levels. However, there was no design for lumbar cages which was consistently favored. Autograft bone graft surgeries were the most common (60.0%). Amongst the synthetic options, hydroxyapatite-based bone graft substitutes (76.7%) in injectable paste form (80.8%) were preferred.Current lumbar fusion practice is variable and patient-oriented. Findings from this study highlight the need for large-scale investigative surveys and clinical studies aimed to set specific guidelines for certain pathologies or patient categories.