Anterior Lumbar Interbody Fusion as a Salvage Technique for Pseudarthrosis following Posterior Lumbar Fusion Surgery

Surgery for Spinal Stenosis in Achondroplasia: Causes of Reoperation and Reduction of Risks

BACKGROUND

Individuals with achondroplasia are prone to symptomatic spinal stenosis requiring surgery. Revision rates are thought to be high; however, the precise causes and rates of reoperation are unknown. The primary aim of this study is to investigate the causes of reoperation after initial surgical intervention in individuals with achondroplasia and spinal stenosis. In addition, we report on surgical techniques aimed at reducing the risks of these reoperations.

METHODS

A retrospective review was conducted over an 8-year period of all patients with achondroplasia at a single institution that serves as a large referral center for patients with skeletal dysplasias. Patients with achondroplasia who underwent spinal surgery for stenosis were identified and the need for revision surgery was studied. Data collected included demographic, surgical, and revision details. Fisher exact test was used to determine if an association existed between construct type and the need for revisions.

RESULTS

Thirty-three of the 130 (22%) patients with achondroplasia required spinal stenosis surgery. Twenty-four individuals who met the criteria were selected for analysis. The initial spine surgery was at an average age of 18.7 years (SD: 10.1 y). Nine patients (38%) required revision surgeries, and 3 required multiple revisions. Five of 9 (56%) of the revisions had primary surgery at an outside institution. Revision surgeries were due to caudal pseudarthrosis (the distal instrumented segment) (8), proximal junctional kyphosis (PJK) (7), and new neurological symptoms (7). There was a significant association found between construct type and the need for revision ( P =0.0111). The pairwise comparison found that short fusions were significantly associated with the need for revision compared with the interbody group ( P =0.0180). PJK was associated with short fusions when compared with the long fusion group ( P =0.0294) and the interbody group ( P =0.0300). Caudal pseudarthrosis was associated with short fusions when compared with the interbody group ( P =0.0015). Multivariate logistic regression found long fusion with an interbody was predictive of and protective against the need for revision surgery ( P =0.0246). To date, none of the initial cases that had long fusions with caudal interbody required a revision for distal pseudarthrosis.

CONCLUSIONS

In patients with achondroplasia, the rate of surgery for spinal stenosis is 22% and the risk of revision is 38% and is primarily due to pseudarthrosis, PJK, and recurrent neurological symptoms. Surgeons should consider discussing spinal surgery as part of the patient's life plan and should consider wide decompression of the stenotic levels and long fusion with the use of an interbody cage at the caudal level in all patients to reduce risks of revision.

LEVEL OF EVIDENCE

Level IV-Retrospective case series.

Retrospective analysis of medium-term outcomes following anterior lumbar interbody fusion surgery performed in a tertiary spinal surgical centre

INTRODUCTION

Anterior lumbar interbody fusion (ALIF) can treat spondylolisthesis, degenerative disc disease and pseudoarthrosis. This approach facilitates complete discectomy, disc space distraction, indirect decompression of neural foramina and placement of large interbody devices. Several intra- and postoperative complications can be attributed to the anterior approach: vascular/visceral injury, hypogastric plexus injury and urogenital consequences. Spine-specific complications include implant migration, graft failure, pseudoarthrosis and persistent symptomology.

METHODS

This retrospective study reviewed patient demographics, medium-term outcomes and complication rates following ALIF surgery performed over a 5-year period. A total of 110 consecutive patients had undergone ALIF surgery at a single tertiary spinal centre. The database was reviewed with a primary outcome of identifying postoperative 90-day complications and whether a revision anterior operation was required after primary ALIF.

RESULTS

No patients required revision anterior operation after their primary ALIF surgery by final follow-up. Out of 110 patients, 11 (10%) recorded a complication attributed to the anterior stage of their operation within 90 days.

CONCLUSIONS

Our 90-day complication rate of 10% lies within the 2.6% acute complication and 40% overall complications rates described in previous literature. The risk of vascular/visceral injury is significant (3%) and we recommend that ALIF be performed as a dual surgeon procedure with a vascular-trained access surgeon accompanying the spinal surgeon. ALIF is a valid revision surgical option for failed posterior approaches leading to complications such as pseudoarthrosis. In our sample, 89% of patients were managed with posterior fixation to augment the anterior fusion as, biomechanically, this is a proven construct.

Feasibility of Multilevel Anterior Lumbar Interbody Fusion in a Patient With an Intrapelvic Kidney: A Case Report

CASE

We present a 64-year-old woman with loss of lumbar lordosis with a preoperative computed tomography scan demonstrating the presence of an intrapelvic kidney with aberrant vasculature. A 2-level anterior lumbar interbody fusion with a 2-level oblique interbody fusion was planned. An anterior approach was successfully used to access the anterior spine without damaging the pelvic kidney.

CONCLUSION

Anatomic variations, both congenital and acquired, can pose significant challenges to surgeons during their dissection. We present a case where multilevel anterior interbody cage placement can be safely performed, even in a patient whose anatomy is complicated by an intrapelvic kidney.

Transforaminal lumbar interbody fusion with a tantalum cage: lumbar lordosis redistribution and sacral slope restoration with a modified posterior technique

BACKGROUND

Transforaminal lumbar interbody fusion (TLIF), a commonly used procedure in spine surgery, has the advantage of a lower incidence of nerve lesions compared to the posterior lumbar interbody fusion (PLIF) technique. The intersomatic arthrodesis has always been carried out with a single tantalum cage normally used for PLIF. Tantalum is a metal that is particularly used in orthopedic surgery. It has a modulus of elasticity similar to marrow and leads to high primary stability of the implant.

MATERIALS AND METHODS

Our study was a retrospective monocentric observational study evaluating clinical and radiological outcomes of tantalum cages in a modified TLIF technique with posterior instrumentation and autologous and/or homologous posterolateral bone grafting. The aim of the study was to evaluate clinical outcomes and the increase in or redistribution of lumbar lordosis. The intersomatic arthrodesis was always carried out with a single tantalum cage normally used for PLIF to reduce the neurological risk. We retrospectively studied 105 patients who were treated with a modified unilateral TLIF approach by two surgeons between 2013 and 2018. We evaluated the Oswestry Disability Index (ODI), Visual Analogue Scale (VAS) for back pain, global lumbar lordosis, lordosis of L4-sacrum, segmental lordosis of functional motion units that underwent arthrodesis, pelvic tilt, pelvic incidence, and the sacral slope in 77 patients. All patients were suffering from grade III or IV Pfirrmann, instability, or foraminal post-laminectomy stenosis and/or grade I-II degenerative spondylolisthesis or low-grade isthmic spondylolisthesis. They had no significant sagittal imbalance, with a sagittal vertical axis (SVA) of < 5 mm. The average follow-up duration was 30 months.

RESULTS

We achieved excellent clinical results, with only four cases of failure (5.2%). Moreover, we noticed a statistically significant redistribution of lumbar lordosis, with an average percentage increase in L4-S1 lordosis equal to 19.9% (P < 0.001), an average increase in the L4-S1/Lumbar lordosis (LL) ratio from 0.53 to 0.63 (P < 0.001), and a mean percentage increase in sacral slope equal to 7.6% (P < 0.001).

CONCLUSION

Thanks to the properties of tantalum, our modified single-portal TLIF technique is a valid surgical solution to obtain a solid arthrodesis and restore the correct lumbar lordosis distribution while reducing neurological complications and the number of failures.

LEVEL OF EVIDENCE

4 Trial registration statement: retrospective observational study, no trial registration.

Adult spinal deformity patients revised for pseudarthrosis have comparable two-year outcomes to those not undergoing any revision surgery

PURPOSE

This study aimed to evaluate whether adult spinal deformity patients undergoing revision for symptomatic pseudarthrosis have comparable two-year outcomes as patients who do not experience pseudarthrosis.

METHODS

Patients whose indexed procedure was revision for pseudarthrosis (pseudo) were compared with patients who underwent a primary procedure and did not have pseudarthrosis by 2Y post-op (non-pseudo). Patients were propensity-matched (PSM) based on baseline (BL) sagittal alignment, specifically C7SVA and CrSVA-Hip. Key outcomes were 2Y PROs (SRS and ODI) and reoperation. All patients had a minimum follow-up period of two years.

RESULTS

A total of 224 patients with min 2-year FU were included (pseudo = 42, non-pseudo = 182). Compared to non-pseudo, pseudo-patients were more often female (P = 0.0018) and had worse BL sagittal alignment, including T1PA (P = 0.02], C2-C7 SVA [P = 0.0002], and CrSVA-Hip [P = 0.004]. After 37 PSM pairs were generated, there was no significant difference in demographics, BL and 2Y alignment, or operative/procedural variables. PSM pairs did not report any significantly different PROs at BL. Consistently, at 2Y, there were no significant differences in PROs, including SRS function [3.9(0.2) vs 3.7(0.2), P = 0.44], pain [4.0 (0.2) vs. 3.57 (0.2), P = 0.12], and ODI [25.7 (5.2) vs 27.7 (3.7), P = 0.76]. There were no differences in 1Y (10.8% vs 10.8%, P > 0.99) and 2Y (13.2% vs 15.8%, P = 0.64) reoperation, PJK rate (2.6% vs 10.5%, P = 0.62), or implant failure (2.6% vs 10.5%, P = 0.37). Notably, only 2 patients (5.4%) had recurrent pseudarthrosis following revision. Kaplan-Meier curves indicated that patients undergoing intervention for pseudarthrosis had comparable overall reoperation-free survival (log-rank test, χ2 = 0.1975 and P = 0.66).

CONCLUSIONS

Patients undergoing revision for pseudarthrosis have comparable PROs and clinical outcomes as patients who never experienced pseudarthrosis. Recurrence of symptomatic pseudarthrosis was infrequent.

Surgical outcomes of anterior lumbar interbody fusion in revision lumbar interbody fusion surgery

BACKGROUNDS

Anterior lumbar interbody fusion (ALIF) is an attractive option for revision lumbar interbody fusion as it provides wide access for implant removal and accommodation of large interbody grafts for fusion. However, revision lumbar interbody fusion surgery has not been found to result in significantly better functional outcomes compared with other approaches. To date, no prognostic factors of anterior lumbar interbody fusion in revision lumbar interbody fusion have been reported. In this study, we investigated the surgical results and possible prognostic factors of anterior lumbar interbody fusion in revision lumbar interbody fusion.

METHODS

Patients who received revision interbody fusion surgery between January 2010 and May 2018 in our hospital were reviewed. Clinical outcomes were determined according to whether the VAS score improvement in back pain and leg pain reached the minimum clinically important difference (MCID) and Macnab criteria. Radiographic outcomes were assessed with fusion rate, preoperative, and postoperative lumbar lordosis. Operative-relative factors that may affect clinical outcomes, such as BMI, existence of cage migration, cage subsidence, pseudarthrosis, previous procedure, and number of fusion segments, were collected and analyzed.

RESULTS

A total of 22 consecutive patients who received ALIF for revision interbody fusion surgery were included and analyzed. There were 9 men and 13 women with a mean age at operation of 56 years (26-78). The mean follow-up was 73 months (20-121). The minimal clinically important difference (MCID) was reached in 11 (50%) of the patients for back pain and 14 (64%) for leg pain. According to the modified Macnab criteria, 73% of the patients in this study had successful outcomes (excellent or good). The pain and lumbar lordosis had significant improvement (P < 0.05). Preoperative fusion segment ≥ 2 was shown to be a poor prognostic factor for back pain improvement reaching MCID (P = 0.043).

CONCLUSIONS

ALIF has proven effective for revision lumbar fusion surgery, yielding positive clinical and radiographic results. However, having two or more preoperative fusion segments can negatively impact back pain improvement.

LEVEL OF EVIDENCE

IV.

[Revision surgery after previous spinal decompression and fusion for lumbar spinal stenosis]

Nowadays, vertebral stenosis is the most common indication for surgical treatment in patients over 65 years old in spine surgery. According to the literature, there are conflicting data on the incidence and indications for revision surgery after previous spinal decompression and fusion for lumbar spinal stenosis.

OBJECTIVE

To evaluate the incidence and indications for revision surgery after previous spinal decompression and fusion for lumbar spinal stenosis.

MATERIAL AND METHODS

A retrospective single-center study enrolled 1233 patients with lumbar spine stenosis who underwent spinal decompression and fusion surgery between 2014 and 2018. The number and causes of readmission were evaluated.

RESULTS

There were 164 readmissions. Revision surgery at the same level was performed in 63 patients (38.4%), at the higher level - 72 (43.9%), at the lower level - in 29 (17.7%) patients. The most common indication for readmission was spondyloarthrosis with facet joint syndrome (94 (57.3%) patients). The second common complication was pseudoarthrosis (26 (15.9%) patients). These ones comprised 2.1% of all patients with lumbar spine stenosis.

CONCLUSION

The most common indication for readmission was adjacent segment degeneration. The most severe complications requiring complex and even multiple stage revision surgery were pseudoarthrosis and postoperative spondylodiscitis. Causes of readmission are significantly changing at different periods after surgery.

Lumbar pedicle screw pseudoarthrosis salvage technique with moldable, bioabsorbable, calcium phosphate-based putty: illustrative case

BACKGROUND

Pseudoarthrosis is a complication of spinal fixation. Risk factors include infection, larger constructs, significant medical comorbidities, and diabetes. The authors present a case report of dilated pedicle screw pseudoarthrosis salvaged with moldable, settable calcium phosphate-based putty.

OBSERVATIONS

The patient presented with back pain and radiculopathy in the setting of poorly controlled diabetes. He was taken to the operating room for laminectomy and fusion complicated by postoperative infection requiring incision and drainage. He returned to the clinic 6 months later with pseudoarthrosis of the L4 screws and adjacent segment degeneration. He was taken for revision with extension of fusion. The L4 tracts were significantly dilated. A moldable, bioabsorbable polymer-based putty containing calcium phosphate was used to augment the dilated tract after decortication back to bleeding bone, allowing good purchase of screws. The patient did well postoperatively.

LESSONS

There are several salvage options for clinically significant pseudoarthrosis after spinal fixation, including anterior or lateral constructs, extension, and revision of fusion. The authors were able to obtain good screw purchase with dilated screw tracts after addition of moldable, bioabsorbable polymer-based putty containing calcium phosphate. It appears that this may represent an effective salvage strategy for dilated pseudoarthropathy in select settings to support extension of fusion.

Minimally Invasive Transforaminal versus Anterior Lumbar Interbody Fusion in Patients Undergoing Revision Fusion: Clinical Outcome Comparison

OBJECTIVE

We aim to compare perioperative/postoperative clinical outcomes between minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) and anterior lumbar interbody fusion (ALIF) in patients presenting for revision surgery.

METHODS

A retrospective database was reviewed for procedures between November 2005 and December 2021. Revision MIS-TLIF/ALIFs were included, whereas primary fusions or diagnosis of infection/malignancy/trauma were excluded. Patients were grouped into MIS-TLIF/ALIF cohorts. Preoperatively/postoperatively collected patient-reported outcome measures (PROMs) included visual analog scale back/leg score, Oswestry Disability Index, Patient-Reported Outcome Measurement Information System-Physical Function (PROMIS-PF), and Short-Form 12-Item Survey Mental/Physical Composite Scores.

RESULTS

A total of 164 patients were eligible, with 84 patients in the MIS-TLIF cohort. The presence of degenerative spondylolisthesis and central stenosis, narcotic consumption on postoperative day 0/1, and postoperative urinary retention rates was greater in the MIS-TLIF cohort (P ≤ 0.036, all). Preoperative PROMs between cohorts did not significantly differ. Significantly favorable postoperative PROM scores were shown in the MIS-TLIF cohort with PROMIS-PF at 12 weeks/6 months (P ≤ 0.033, all). Most patients in both cohorts achieved overall minimum clinically important difference for visual analog scale back/leg score, Oswestry Disability Index, Short-Form 12-Item Survey Physical Composite Score, and PROMIS-PF. No differences were noted between cohorts within rates of MCID achievement.

CONCLUSIONS

Patients undergoing revision fusion via MIS-TLIF or ALIF reported similar 1-year postoperative mean outcomes and rates of meaningful clinical achievement for physical function, mental health, disability, and back/leg pain. However, patients undergoing revision MIS-TLIF reported improved physical function at 12 weeks and 6 months. Perioperatively, patients undergoing revision MIS-TLIF were noted to consume significantly greater quantities of narcotics.

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.

Revision for cage migration after transforaminal/posterior lumbar interbody fusion: how to perform revision surgery?

Background

Symptomatic pseudarthrosis and cage migration/protrusion are difficult complications of transforaminal or posterior lumbar interbody fusion (TLIF/PLIF). If the patient experiences severe radicular symptoms due to cage protrusion, removal of the migrated cage is necessary. However, this procedure is sometimes very challenging because epidural adhesions and fibrous union can be present between the cage and vertebrae. We describe a novel classification and technique utilizing a navigated osteotome and the oblique lumbar interbody fusion at L5/S1 (OLIF51) technique to address this problem.

Methods

This retrospective study investigated consecutive patients with degenerative lumbar diseases who underwent TLIF/PLIF. Symptomatic cage migration was evaluated by direct examination, radiography, and/or computed tomography (CT) at 1, 3, 6, 12, and 24 months of follow-up. Cage migration/protrusion was defined as symptomatic cage protrusion > 5 mm from the posterior border of the over and underlying vertebral body compared with initial CT. We evaluated patient characteristics including body mass index, smoking history, fusion level, and cage type. A total of 113 patients underwent PLIF/TLIF (PLIF n = 30, TLIF n = 83), with a mean age of 71.1 years (range, 28–87 years). Mean duration of follow-up was 25 months (range, 12–47 months).

Results

Cage migration was identified in 5 of 113 patients (4.4%). All cases of symptomatic cage migration involved the L5/S1 level and the TLIF procedure. Risk factors for cage protrusion were age (younger), sex (male), and level (L5/S1). The mean duration to onset of cage protrusion was 3.2 months (range, 2–6 months). We applied a new classification for cage protrusion: type 1, only low back pain without new radicular symptoms; type 2, low back pain with minor radicular symptoms; or type 3, cauda equina syndrome and/or severe radicular symptoms. According to our classification, one patient was in type 1, three patients were in type 2, and one patient was in type 3. For all cases of cage migration, revision surgery was performed using a navigated high-speed burr and osteotome, and the patient in group 1 underwent additional PLIF without removal of the protruding cage. Three revision surgeries (group 2) involved removal of the protruding cage and PLIF, and one revision surgery (group 3) involved anterior removal of the cage and OLIF51 fusion.

Conclusions

The navigated high-speed burr, navigated osteotome, and OLIF51 technique appear very useful for removing a cage with fibrous union from the disc in patients with pseudarthrosis. This new technique makes revision surgery after cage migration much safer, and more effective. This technique also reduces the need for fluoroscopy.

Single-Position Anterior Column Lateral Lumbar Interbody Fusion

Lateral lumbar fusion is a commonly used spinal fusion technique that allows for indirect neural decompression while correcting sagittal malalignment. The lateral position has evolved to include placement of percutaneous pedicle screw fixation, anterior longitudinal ligament release, and approach the L5-S1 segment. This review article focuses on the anatomy and technique of the single-position anterior column spinal fusion and highlights the recent trends, outcomes, and future directions for the approach.

Increased risk of postoperative wound complications among obesity classes II & III after ALIF in 10-year ACS-NSQIP analysis of 10,934 cases

BACKGROUND CONTEXT

Anterior lumbar interbody fusion (ALIF) procedures for lumbar spine disease have been increasing amid a growing obese patient population with limited studies available focusing exclusively on risk-factors for post-operative ALIF complications.

PURPOSE

The objective of this study was to compare 30-day post-operative complications among different obesity World Health Organization classes according to body mass index (BMI) in comparison to non-obese patients who underwent an ALIF procedure.

STUDY DESIGN/SETTING

Retrospective cohort study of the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) from 2009 to 2019.

PATIENT SAMPLE

A total of 10,934 patients undergoing an ALIF.

OUTCOME MEASURES

Primary outcome measures include 30 day cardiac, pulmonary, urinary, infectious, and wound complications. Secondary outcomes included rates of blood transfusion, reintubation, deep vein thrombosis, pulmonary embolism, 30-day return to the operating room (OR), and 30 day mortality.

METHODS

Patients were identified by use of the current procedural terminology codes 22558 and 22585 from 2009 to 2019. Patients were divided into the following groups: non-obese (BMI 18.5-29.9 kg/m²), Obese I (BMI 30-34.9 kg/m²), Obese II (BMI 35-39.9 kg/m²), and Obese III (BMI ≥40 kg/m²). Age, gender, race, American Society of Anesthesiologists status, smoking status, hypertension requiring medication, steroid used, chronic obstructive pulmonary disease, history of a bleeding disorder, and diabetes was identified as risk factors after a univariate analysis conducted for demographic variables and pre-operative comorbidities. A multivariate logistic regression analysis was then performed to adjust for these preoperative risk factors and compare obesity classes I-III to non-obese patients.

RESULTS

Obesity classes II and III had a significant odds ratio (OR) for superficial infection (OR:2.7, 95%CI(1.7-4.5); OR:2.8, 95%CI(1.5-5.2) respectively), organ space infection (OR:3.8, 95%CI(1.6-7.4); OR:3.2, 95%CI(1.1-9.9) respectively), wound disruption (OR:2.8, 95%CI(1.1-7.4); OR:4.6, 95%CI(1.6-13.6) respectively), and total wound complication (OR:2.6, 95%CI(1.8-3.9); OR:3.4, 95%CI(2.2-5.4) respectively) following a multivariate logistic regression analysis.

CONCLUSIONS

Risk for post-operative wound complications following an ALIF were found to be significantly higher for obesity classes II-III in comparison to non-obese patients. These findings can further support the use of additional wound care in the perioperative setting for certain levels of obesity.

Discoplasty as a salvage technique for pseudoarthrosis following multilevel TLIFS: A case report

BACKGROUND

Pseudoarthrosis, often defined as a failure to achieve osseous fusion by the 1-year post-operative time point. Despite its relatively high prevalence, there is still lack of clinical evidence on salvage options for lumbar pseudoarthrosis. Lumbar interbody fusion is generally accepted as a useful surgical treatment for patients with pseudoarthrosis. Several techniques are available to achieve stabilization of the lumbar spine including the anterior lumbar interbody fusion (ALIF), posterior lumbar interbody fusion (PLIF), transforaminal interbody fusion (TLIF), direct lateral interbody fusion, posterolateral only (intertransverse) fusion, and facet or pedicle screw/rod placement. We present a case report of discoplasty as a salvage option for pseudoarthrosis following lumbar fusion surgery using multilevel TLIFs.

METHOD

This study is a case report. A female patient, 79 year old, came with recurrent backpain at the lumbar area that got worse during the past 3 months. She underwent posterior lumbar fusion surgery of L3-S1 by pedicle screw and transforaminal interbody fusion at the level of L3-S1. Three years later she experienced another episode of back pain and underwent pedicle screws removal to improve her pain. Two years later complaint reappeared. The pain was rated 7/10 in standing position and improved to 5/10 with resting in horizontal position. We followed up this patient for 1 month after surgery.

RESULT

After surgery, VAS score was decreased from 7/10 into 1/10 in standing position and patient was able to stand and walk using a walker. Postoperatively plain radiograph was performed and there was no complication. In a month follow up, the VAS score was 1/10 with ODI score reduces significantly from 38% to 4% showing only minimal disability.

CONCLUSION

Salvage discoplasty for pseudoarthrosis following posterior lumbar fusion surgery is rarely reported, but it appears to be viable option aside from ALIF that results in significant improvement in clinical outcomes. Discoplasty offers a less invasive solution in elderly patients which significantly reduces the symptoms and improves the quality of life of the affected patients.

LUMBAR ARTHRODESIS IN DEGENERATIVE SPINE: POST OPERATIVE RESULTS AND RADIOGRAPHIC EVALUATION

ABSTRACT Objective: To relate the radiographic fusion rate and the surgical results in patients undergoing posterolateral arthrodesis with instrumentation of the lumbar spine for the treatment of degenerative disorders. Method: A descriptive, retrospective, case series, observational study, based on medical records and imaging studies of 76 patients over 18 years of age (39 to 88 years) who underwent posterolateral lumbar arthrodesis. Data related to the presence of comorbidities were compiled and clinical outcomes were measured using specific questionnaires collected pre-surgical and 1 year after surgery. Fusion quality, as described by Christensen, was assessed from radiographic images by two examiners. The VAS, EQ-5D and Roland Morris questionnaires were used preoperatively and 1 year after surgery to assess pain, quality of life and function, respectively. Result: It was observed improvement in pain, function and quality of life after 1 year post-surgical. Pain, measured by VAS, had a reduction from 7.92 to 3.16 (p-value <0.001), the function evaluated by the Roland Morris score, also showed a reduction from 14.90 to 7.06 (p-value <0.001) . Culminating with the improvement in quality of life, measured by the EQ-5D, where there was a median increase in the score from 0.5672 to 0.7002 (p-value = 0.002). Conclusion: The absence of radiographic fusion has no direct correlation with worse results in clinical outcomes at 01 year after surgery. Most patients showed clinical improvement with no statistical difference in relation to cases in which bone fusion was obtained. Level of evidence IV; retrospective observation.

Salvage Oblique Lateral Interbody Fusion for Pseudarthrosis after Posterior/Transforaminal Lumbar Interbody Fusion: A Technical Note

OBJECTIVE

This study aims to demonstrate the efficacy of salvage oblique lumbar interbody fusion (OLIF) surgery for pseudarthrosis after posterior/transforaminal lumbar interbody fusion (PLIF/TLIF).

METHODS

The study group were patients with leg or back pain induced by pseudarthrosis after PLIF/TLIF. These patients underwent salvage OLIF surgeries in our institutions between July 2015 and Oct 2019. We retrospectively evaluated their clinical and radiographic outcomes.

RESULTS

Seven consecutive patients (all male; mean age 68.4 ± 9.3 years, range 53-81 years) were included in this study. There was no intraoperative complications in all cases. Six of 7 patients achieved bone union (at average 33.4 months follow-up) and had a successful postoperative course. Only 1 patient failed to gain bony fusion and required additional revision surgery due to progression of sagittal and coronal malalignment at 18 months after salvage OLIF surgery.

CONCLUSIONS

The salvage OLIF approach was useful option for pseudarthrosis after PLIF/TLIF. It enabled us to build a rigid anterior support, allowed for extensive curettage of intervertebral scar tissue, and reduced the rate of the complications associated with dealing with posterior scar tissue.

Clinical and radiological results of indirect decompression after anterior lumbar interbody fusion in central spinal canal stenosis

OBJECTIVE

Whereas the benefits of indirect decompression after lateral lumbar interbody fusion are well known, the effects of anterior lumbar interbody fusion (ALIF) have not yet been verified. The purpose of this study was to evaluate the clinical and radiological effects of indirect decompression after ALIF for central spinal canal stenosis. In this report, along with the many advantages of the anterior approach, the authors share cases with good outcomes that they have encountered.

METHODS

The authors performed a retrospective analysis of 64 consecutive patients who underwent ALIF for central spinal canal stenosis with instability and mixed foraminal stenosis between January 2015 and December 2018 at their hospital. Clinical assessments were performed using the visual analog scale score, the Oswestry Disability Index, and the modified Macnab criteria. The radiographic parameters were determined from pre- and postoperative cross-sectional MRI scans of the spinal canal and were compared to evaluate neural decompression after ALIF. The average follow-up period was 23.3 ± 1.3 months.

RESULTS

All clinical parameters, including the visual analog scale score, Oswestry Disability Index, and modified Macnab criteria, improved significantly. The mean operative duration was 254.8 ± 60.8 minutes, and the intraoperative bleeding volume was 179.8 ± 119.3 ml. In the radiological evaluation, radiological parameters of the cross-sections of the spinal canal showed substantial development. The spinal canal size improved by an average of 43.3% (p < 0.001) after surgery. No major complications occurred; however, aspiration guided by ultrasonography was performed in 2 patients because of a pseudocyst and fluid collection.

CONCLUSIONS

ALIF can serve as a suitable alternative to extensive posterior approaches. The authors suggest that ALIF can be used for decompression in central spinal canal stenosis as well as restoration of the foraminal dimensions, thus allowing decompression of the nerve roots.

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.

Risk Factors Associated With Femoral Ring Allograft Breakage in ALIF

STUDY DESIGN

This is a retrospective chart review.

OBJECTIVES

To identify the incidence of, and variables correlated with, femoral ring allograft (FRA) fracture following anterior lumbar interbody fusion (ALIF).

METHODS

All patients who underwent ALIF using FRAs at an academic institution over 10 years were included. Postoperative radiographs were reviewed by both the primary and senior authors; fracture and no-fracture groups were created for comparison. Patient and surgical characteristics were extracted from electronic medical records. Frequency data comparisons were performed using contingency table analysis; comparisons of means were analyzed for continuous variables. A multivariate linear regression model was developed using screw use, graft height <12 mm, index level, and weight as variables.

RESULTS

A total of 76 FRAs in 59 patients were identified, 13 (17%) of which fractured. Age, sex, smoking status, use of buttress screws, weight, index level, and presence of spondylolisthesis were not correlated with incidence of fracture (P > .05). There was a significant correlation between the height of FRA and incidence of fracture; 2% (1/52) of grafts ≥12 mm and 50% (12/24) of grafts <12 mm fractured (P < .0001). Using ordinary least-squares regression, this result was independent of patient weight, use of screws, and index level. Of 10 patients, 9 did not require revision surgery to achieve fusion.

CONCLUSIONS

Graft height was the only variable correlated with incidence of FRA fracture. Graft height <12 mm is an independent risk factor for FRA fracture in patients undergoing ALIF, and their use should be avoided in ALIF procedures.

Safety Profile and Radiographic and Clinical Outcomes of Stand-Alone 2-Level Anterior Lumbar Interbody Fusion: A Case Series of 41 Consecutive Patients

Objective: The use of stand-alone 2-level anterior lumbar interbody fusion (ALIF) for degenerative lumbar disease has been increasing as an alternative to routinely augmenting these constructs with posterior fixation or fusion. Despite the potential benefits of a stand-alone approach (decreased cost and operative time, decreased pain and early mobilization), there is a paucity of information regarding these operations in the literature. This investigation aimed to determine the safety profile, radiographic outcomes including fusion rates, improvement in preoperative pain, and spinopelvic parameter modification, for patients undergoing stand-alone 2-level ALIF.

Methods: This retrospective case series involved a chart review of all patients undergoing 2-level stand-alone ALIF at a single tertiary hospital from 2008 to 2018. Data included patient demographics, hospitalization, complications and radiological studies. Visual analog scale (VAS) back and leg scores were measured via patient-administered surveys preoperatively and up to 18 weeks postoperatively.

Results: Forty-one patients who underwent L4-S1 stand-alone ALIF were included. Sixteen (39%) of patients had undergone previous posterior lumbar surgery. Length of stay averaged 4.2 days. Complication rates were comparable to 1-level ALIF. Two patients required reoperation. Fusion rates were 100% for L4-5 and 94.4% for L5-S1. There was no significant change in lumbar lordosis (LL) or LL-pelvic incidence (PI), but there was improved segmental lordosis (SL) and disc height at L4-S1 on final follow-up imaging. There was also modest but statistically significant improvement in VAS back and leg scores.

Conclusions: Stand-alone 2-level ALIF is an option for a surgeon to perform in the absence of significant instability, even in the setting of prior posterior surgery. These procedures increase SL and disc height, but do not have the same effect on LL or LL-PI.

Clinical Efficacies of the Minimal Retroperitoneal Approach for Infectious Spondylodiscitis: A Clinical Case Series

Introduction

An anterior surgical approach for severe infectious spondylodiscitis in the lumbar region is optimal but not always atraumatic. The aim of this study was to evaluate the efficacy and safety of a minimal anterior-lateral retroperitoneal approach, also known as a surgical approach for oblique lumbar interbody fusion, for cases with severe infectious spondylodiscitis with osseous defects.

Methods

Twenty-four consecutive patients who underwent anterior debridement and spinal fusion with an autologous strut bone graft for infectious spondylodiscitis with osseous defects were reviewed retrospectively. Eleven patients underwent the minimal retroperitoneal approach (Group M), and 13 underwent the conventional open approach (Group C). Peri- and postoperative clinical outcomes, that is, estimated blood loss (EBL), operative time (OT), creatine kinase (CK) level, visual analog scale (VAS), and rates of bone union and additional posterior instrumentation, were evaluated, and the differences between both groups were assessed statistically.

Results

Mean EBL, serum CK on the 1^st postoperative day, and VAS on the 14^th postoperative day were 202.1 mL, 390.9 IU/L, and 9.5 mm in Group M and 648.3 mL, 925.5 IU/L, and 22.3 mm in Group C, respectively, with statistically significant differences between the groups. There were no statistically significant intergroup differences in OT and rates of bone union and additional posterior instrumentation.

Conclusions

Anterior debridement and spinal fusion using the minimal retroperitoneal approach is a useful and safe surgical technique. Although a preponderance of the minimal approach regarding early bone union is not validated, this technique has the advantages of conventional open surgery, but reduces blood loss, muscle injury, and pain postoperatively.

Assessment of Great Vessels for Anterior Access of L5/S1 Using Patient Positioning

STUDY DESIGN

This was a prospective cross-sectional study.

PURPOSE

The aim was to describe the effect of patient positioning, from supine to lateral decubitus position, on the width of the L5/S1 anterior disk space defined by the great vessels.

OVERVIEW OF LITERATURE

The application of the lateral decubitus position interbody fusion has been rapidly increasing; however, there are concerns regarding the access to the lumbosacral region due to the great vessels, which necessitates further morphometric data.

METHODS

A total of 20 consecutive live patients awaiting lumbar surgery were subjected to two magnetic resonance imaging scans on the same day in both supine and lateral decubitus positions at a single center to investigate the anterior L5/S1 disk space.

RESULTS

The bare anterior L5/S1 disk window was present in all patients of this study population, and the mean width was 27 mm in the supine and 22 mm in the lateral decubitus position, with a mean reduction of 5.2 mm between the positions. The oblique corridor angle was measured at a mean of 33°.

CONCLUSIONS

The bare window of L5/S1 disk space was present within this population group, and it was found to be mobile and changed significantly with patient positioning. Therefore, the spine surgeon or the access surgeon must consider the increased potential vascular risk during disk access in lateral decubitus anterior lumbar interbody spinal fusion surgery.

90-day Readmission Rates for Single Level Anterior Lumbosacral Interbody Fusion: A Nationwide Readmissions Database Analysis

STUDY DESIGN

Nationwide Readmissions Database Study.

OBJECTIVE

To investigate the patterns of readmissions and complications following hospitalization for elective single level anterior lumbobsacral interbody fusion.

SUMMARY OF BACKGROUND DATA

Lumbar interbody spine fusions for degenerative disease have increased annually in the United States, including associated hospital costs. Anterior lumbar interbody fusions (ALIFs) have become popularized secondary to higher rates of fusion compared with posterior procedures, and preservation of posterior elements. Prior national databases have sought to study readmission rates with some limitations due to older diagnosis and procedure codes. The newer 2016 International Classification of Diseases Tenth Revision, Clinical Modification (ICD-10 CM) includes more specification of the surgical site.

METHODS

We utilized the 2016 United States Nationwide Readmissions Database (NRD), this nationally representative, all-payer database that includes weighted probability sample of inpatient hospitalizations for all ages. We identified all adults (≥ 18 yrs) using the 2016 ICD-10 coding system who underwent elective primary L5-S1 ALIF and examined rates of readmissions within 90 days of discharge.

RESULTS

Between January and September 2016, a total of 7029 patients underwent elective stand-alone L5-S1 ALIF who were identified from NRD of whom 497 (7.07%) were readmitted within 90 days of their procedure. No differences in sex were appreciated. Medicare patients had statistically significant higher readmission rates (47.69%) among all payer types. With respect to intraoperative complications, vascular complications had statistically significant increased odds of readmission (OR, 3.225, 95% CI, 0.59 -1.75; P = 0.0001). Readmitted patients had higher total healthcare costs.

CONCLUSION

The 90-day readmission rate following stand-alone single level lumbosacral (L5-S1) ALIF was 7.07%. ALIF procedures have increased in frequency, and an understanding of the comorbidities, age-related demographics, and costs associated with 90-day readmissions are critical. Surgeons should consider these risk factors in preoperative planning and optimization.

LEVEL OF EVIDENCE

3.

Revision strategies for failed adult spinal deformity surgery

PURPOSE

The aim of this study is to analyse the results of revision surgery for failed adult spinal deformity patients and to describe the surgical strategy selection process, based on the identification of the main clinical diagnosis responsible for failure.

METHODS

We retrospectively reviewed the clinical and radiological data of 77 consecutive patients treated in a 3-year time (2016-2019) for surgical revision of long fusion (more than five levels fused) for adult spinal deformity in a high-volume spine centre, divided into four groups based on the diagnosis: rod breakage (RB) group, proximal junctional failure (PJF) group, distal junctional failure (DJF) group and loss of correction (LOC) group with symptomatic sagittal or coronal malalignment (including iatrogenic flatback).

RESULTS

Seventy-seven patients met our inclusion criteria, with a female prevalence (66 F vs. 11 M). The mean age at revision surgery was 63. Fused levels before surgery were averagely 12, and revision added averagely two levels to the preexisting fusion area. Clinical status was apparently improved in ODI scores and VAS scores, while it was slightly worsened in SF36 scores. Different diagnosis groups have been addressed with different surgical strategies, according to the different surgical goals: interbody cages and multi-rod construct to improve stiffness and favour bony fusion, "kickstand" rod and "tie" rod to correct coronal and sagittal malalignment, specific rod contouring and proximal hooks in "claw" configuration to reduce mechanical stress at the proximal junctional area. Intraoperative complications occurred in 18% of patients and perioperative complications in 39%.

CONCLUSION

Revision surgery in long fusions for adult spinal deformity is a challenging field. Surgical strategy should always be planned carefully. A successful treatment is a direct consequence of a correct preoperative diagnosis, and surgery should address the primary cause of failure. All the above-mentioned surgical techniques and clinical skills should be part of surgeon's expertise when managing these patients. These slides can be retrieved under Electronic Supplementary Material.

Neurologic Injury in Complex Adult Spinal Deformity Surgery: Staged Multilevel Oblique Lumbar Interbody Fusion (MOLIF) Using Hyperlordotic Tantalum Cages and Posterior Fusion Versus Pedicle Subtraction Osteotomy (PSO)

STUDY DESIGN

A retrospective review of prospectively collected data.

OBJECTIVE

The aim of this study was to determine the safety of MOLIF versus PSO.

SUMMARY OF BACKGROUND DATA

Complex adult spinal deformity (CASD) represents a challenging cohort of patients. The Scoli-RISK-1 study has shown a 22.18% perioperative risk of neurological injury. Restoration of sagittal parameters is associated with good outcome in ASD. Pedicle subtraction osteotomies (PSO) is an important technique for sagittal balance in ASD but is associated with significant morbidity. The multilevel oblique lumbar interbody fusion (MOLIF) is an extensile approach from L1 to S1.

METHODS

Single surgeon series from 2007 to 2015. Prospectively collected data. Scoli-RISK-1 criteria were refined to only include stiff or fused spines otherwise requiring a PSO. Roentograms were examined preoperatively and 2 year postoperatively. Primary outcome measure was the motor decline in American Spinal Injury Association (ASIA) at hospital discharge, 6 weeks, 6 months, and 2 years. Demographics, blood loss, operative time, spinopelvic parameters, and spinal cord monitoring (SCM) events.

RESULTS

Sixty-eight consecutive patients were included in this study, with 34 patients in each Group. Group 1 (MOLIF) had a mean age 62.9 (45-81) and Group 2 (PSO) had a mean age of 66.76 years (47-79); 64.7% female versus PSO 76.5%; Body Mass Index (BMI) Group 1 (MOLIF) 28.05 and Group 2 (PSO) 27.17. Group 1 (MOLIF) perioperative neurological injury was 2.94% at discharge but resolved by 6 weeks. Group 2 (PSO) had five neurological deficits (14.7%) with no recovery by 2 years. There were four SCM events (SCM). In Group 1 (MOLIF), there was one event (2.94%) versus three events (8.88%) in Group 2 (PSO).

CONCLUSION

Staged MOLIF avoids passing neurological structures or retraction of psoas and lumbar plexus. It is safer than PSO in CASD with stiff or fused spines with a lower perioperative neurological injury profile. MOLIF have less SCM events, blood loss, and number of levels fused.

LEVEL OF EVIDENCE

3.

Rational decision making in a wide scenario of different minimally invasive lumbar interbody fusion approaches and devices

With the proliferation of a variety of modern MIS spine surgery procedures, it is mandatory that the surgeon dominate all aspects involved in surgical indication. The information related to the decision making in patient selection for specific procedures is mandatory for surgical success. The objective of this study is to present decision-making criteria in minimally invasive surgery (MIS) selection for a variety of patients and pathologies. In this article, practicing surgeons who specialize in various MIS approaches for spinal fusion were engaged to provide expert opinion and literature review on decision making criteria for several MIS procedures. Pros, cons, relative limitations, and case examples are provided for patient selection in treatment with MIS posterolateral fusion (MIS-PLF), mini anterior lumbar interbody fusion (mini-ALIF), lateral interbody fusion (LLIF), MIS posterior lumbar interbody fusion (MIS-PLIF) and MIS transforaminal lumbar interbody fusion (MIS-TLIF). There is a variety of aspects to consider when deciding which modern MIS surgical approach is most appropriate to use based on patient and pathologic characteristics. The surgeon must adapt them to the characteristic of each type of patients, helping them to choose the most effective and efficient therapeutic option for each case.

Risk Factors for Readmissions Following Anterior Lumbar Interbody Fusion

STUDY DESIGN

Retrospective study of prospectively collected data.

OBJECTIVE

To analyze the incidence and risk factors for readmissions following anterior lumbar interbody fusion.

SUMMARY OF BACKGROUND DATA

No study has yet reported readmission rates for a specific lumbar surgical approach. There is evidence to indicate differences in perioperative complication rates between anterior versus posterior lumbar interbody fusion techniques, which may translate into differences in readmission rates.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program is a large multicenter clinical registry that prospectively collects preoperative risk factors, intraoperative variables, and 30-day postoperative morbidity and mortality outcomes from about 400 hospitals nationwide. Current Procedural Terminology codes were used to query the database for adults who underwent anterior lumbar interbody fusion. Patients were separated into groups of those with and without 30-day readmissions. Univariate analysis and multivariate logistic regression were used to analyze the effect of different risk factors on 30-day readmissions.

RESULTS

Multivariate analysis showed that morbid obesity (odds ratio 15.6, P = 0.002) and alcohol use (odds ratio 16.9, P = 0.004) independently predicted unplanned 30-day readmission. Sex, pulmonary comorbidity, cardiac comorbidity, and steroid use were not found to be significant independent predictors of unplanned 30-day readmission in anterior lumbar interbody fusion.

CONCLUSION

Adult patients undergoing anterior lumbar interbody fusion who were morbidly obese and had history of alcohol use are at increased risk for 30-day readmissions. Future studies should look to directly compare readmission rates and risk factors between alternative lumbar interbody surgical approaches with longer follow-up and more clinical and radiological parameters investigated.

LEVEL OF EVIDENCE

3.

Anterior lumbar interbody fusion (ALIF) as an option for recurrent disc herniations: a systematic review and meta-analysis

Background

Recurrent intervertebral disc herniation is a relatively common occurrence after primary discectomy for lumbar intervertebral disc herniation. For recurrent herniations after repeat discectomies, a growing body of evidence suggests that fusion is effective in appropriately selected cases. Theoretically, anterior lumbar interbody fusion (ALIF) allows for comprehensive discectomy, less trauma to spinal nerves and paraspinal muscles and avoidance of the disadvantages of repeat posterior approaches. However, ALIF has also been associated with risk of vascular injury and retrograde ejaculation. This current systematic review and meta-analysis aims to assess the viability of ALIF as a surgical treatment for recurrent disc herniations.

Methods

Seven studies were identified from six electronic databases and secondary reference lists. Pre-defined endpoints were extracted from the included studies and meta-analyzed.

Results

For the 181 patients from included studies, ALIF resulted in significant average improvements in Oswestry Disability Index (ODI) scores (50.49%, P<0.001), Visual Analogue Scale (VAS) back pain scores (47.85%, P<0.001) and VAS leg pain scores (37.00%, P<0.001). Average blood loss was acceptable at 122 mL (P<0.001) and average operation duration was 89 minutes (P<0.001). Average hospital stay was 5.28 days (P<0.001). Only 22 perioperative complications were reported, with subsidence the most commonly reported complication.

Conclusions

Pooled evidence suggests that ALIF is a feasible approach for the treatment of recurrent disc herniations, demonstrating significant improvements in back and leg pain and minimal complications. These findings warrant further investigation in large prospective registries and multi-center studies.

Intraoperative navigation for accurate midline placement of anterior lumbar interbody fusion and total disc replacement prosthesis

Anterior lumbar approach techniques for the management of discogenic back pain and placement of spinal instrumentation such as fusion and disc replacement prosthesis is becoming increasingly popular. To date, no studies have reported the clinical usage of spinal navigation with anterior lumber interbody fusion (ALIF) and total disk replacement (TDR). We describe a surgical procedure of a 35-year-old patient presenting with discogenic lower back pain treated with an anterior lumbar interbody fusion and total disc replacement procedure to highlight the clinical advantages of intraoperative CT spinal navigation for accurate implant placement, therefore optimising peri- and post-operative outcomes.

Subsidence following anterior lumbar interbody fusion (ALIF): a prospective study

BACKGROUND

Anterior lumbar interbody fusion (ALIF) is a widely used surgical technique for disorders of the lumbar spine. One potential complication is the subsidence of disc height in the post-operative period. Few studies have reported the rate of subsidence in ALIF surgery prospectively. We prospectively evaluated the rate of subsidence in adult patients undergoing ALIF.

METHODS

Results were obtained by reviewing scans of 147 patients. Disc heights were measured on radiographic scans taken pre-operatively in addition to post-operatively immediately, at 6 weeks and at 18 months. The anterior and posterior intervertebral disc heights were measured. Subsidence was defined as greater than or equal to 2 mm loss of height.

RESULTS

A total of 15 patients (10.2%) had subsidence, with 7 being male. Each case was of delayed cage subsidence (DCS) >6 weeks postoperatively. The mean subsidence was 4.7 mm (range, 2.4-7.8). Mean anterior disc height was 8.6±0.4 mm preoperatively, which improved to 15.1±0.5 mm at latest follow-up. Mean posterior disc height was 4.7±0.2 mm preoperatively, which improved to 8.7±0.4 mm at latest follow-up. The mean lumbar lordosis (LL) angle was 42.5°±10.8° and the mean local disc angle (LDA) was 6.7°±4.0°. The 91.2% (n=114/125) of patients with appropriate radiological follow-up demonstrated fusion by latest follow-up. There was no correlation between subsidence rate with patient reported outcomes [Visual Analog Scale (VAS), Oswestry Disability Index (ODI) and Short Form 12 Item survey (SF-12)] and fusion rates. There was a significant negative correlation between LL and extent of subsidence (Pearson correlation =-0.754, P=0.012).

CONCLUSIONS

In conclusion, we found that the subsidence rate at follow-up was generally low following standalone ALIF for this patient series. Patient clinical outcomes and bony fusion rates were not significantly influenced by subsidence.

Anterior Lumbar Interbody Fusion With and Without an "Access Surgeon": A Systematic Review and Meta-analysis

STUDY DESIGN

A systematic review and meta-analysis.

OBJECTIVE

The aim of this study was to investigate the outcomes of anterior lumber interbody fusion (ALIF) with and without an "access surgeon."

SUMMARY OF BACKGROUND DATA

Anterior approaches for spine operations have become increasingly popular but may often involve unfamiliar anatomy and territory for spine surgeons, potentially placing the patient at risk to a greater proportion of approach-related complications. Thus, many spine surgeons require or prefer the assistance of an "access surgeon" to perform the exposure. However, there has been much debate about the necessity of an "access surgeon."

METHODS

A systematic search of six databases from inception to April 2016 was performed by two independent reviewers. Meta-analysis was used to pool overall rates, and compare the outcomes of ALIF with an access surgeon and without.

RESULTS

A total of 58 (8028 patients) studies were included in this meta-analysis. The overall intraoperative complications were similar with and without an "access surgeon." The overall pooled rate of arterial injuries [no access 0.44% vs. access 1.16%, odds ratio (OR) 2.67, P < 0.001], retrograde ejaculation (0.41% vs. 0.96%, OR 2.34, P = 0.005), and ileus (1.93% vs. 2.26%, OR 2.45, P < 0.001) was higher with an "access surgeon." However, the overall pooled rates of peritoneal injury (0.44% vs. 0.16%, OR 0.36, P = 0.034) and neurological injury (0.99% vs. 0.11%, OR 0.11, P < 0.001) were lower with an "access surgeon." Total postoperative complications (5.95% vs. 4.08%, OR 0.67, P < 0.001) were lower with an "access surgeon" along with prosthesis complications (1.59% vs. 0.89%, OR 0.56, P < 0.001) and reoperation rates (2.28% vs. 1.31%, OR 0.57, P < 0.001).

CONCLUSION

Compared with no access surgeon, the use of an access surgeon was associated with similar intraoperative complication rates, higher arterial injuries, retrograde ejaculation, ileus, and lower prosthesis complications, reoperation rates, and postoperative complications. In cases wherein exposure may be difficult, support from an "access surgeon" should be available.

LEVEL OF EVIDENCE

1.

Evaluating Outcomes of Stand-Alone Anterior Lumbar Interbody Fusion: A Systematic Review

BACKGROUND

Stand-alone anterior lumbar interbody fusion (ALIF) is an effective surgical approach for selected spinal pathologies. It avoids the morbidity and complications associated with instrumented ALIF, such as plate fixation and the traditionally used posterior approach. Despite improved disc space visualization and clearance, the associated posterior instability and increased risk of nonfusion present major challenges to this approach. The integral cage design aims to address these challenges by providing the necessary stabilization through intracorporeal screws. However, there is limited and controversial data available for stand-alone ALIF and integral cage fixation. To our knowledge, this is the first systematic review to evaluate recent findings on outcomes of stand-alone ALIF devices to explore areas of controversy and identify directions for future research.

METHODS

Two reviewers conducted independent, systematic literature searches for appropriate studies in 5 electronic databases as per Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies were filtered by the use of specified selection criteria, particularly exclusion of studies with supplementary fixation to ALIF and studies published before the year 2000. A total of 17 studies met the criteria, and their data were comprehensively extracted and analyzed.

RESULTS

The current literature is supportive of stand-alone ALIF due to acceptable clinical outcomes, promising fusion rates and disc height restoration. However, data and outcomes remain preliminary, and there are numerous areas of controversy.

CONCLUSIONS

There is evidence for the efficacy and safety of stand-alone ALIF. However, the extent of improvement based on specific indications for surgery remains unclear. Further investigation utilizing more methodologically rigorous studies of long-term outcomes is necessary to address these issues.

Worker's Compensation Status and Outcomes Following Anterior Lumbar Interbody Fusion: Prospective Observational Study

BACKGROUND

Anterior lumbar-interbody fusion (ALIF) is a commonly performed procedure for degenerative spinal disorders with reasonable clinical and safety outcomes, although there is limited evidence regarding the impact of ALIF in patients receiving worker's compensation (WC) compared with those without. The aim of our study is to identify whether WC status affects the clinical outcome and rates of complication following ALIF surgery in a prospective cohort.

METHODS

We followed prospectively 114 consecutive patients undergoing ALIF surgery from 2012-2014. Patients were categorized into 2 groups: those with worker's compensation (WC) (n = 24) and those without (n = 90). Patients were evaluated preoperative and postoperatively. Outcome measures included Short Form-12 (SF-12), Oswestry Disability Index (ODI), surgical complications, and subsidence.

RESULTS

In terms of baseline traits, the WC group had a significantly higher proportion of class III/IV obesity patients, who were younger (46.3 vs. 60.2 years) compared with non-WC. There were no significant differences in fusion rates or preoperative or postoperative disk height. No significant differences were found for hospital stay, blood loss, or operation duration. Similar rates of complications were found between WC versus non-WC cohorts. No significant difference was noted in clinical improvement between the 2 cohorts with SF-12 PCS, SF-12 MCS, or ODI (P = 0.232). No significant difference was found in the proportion of patients achieving minimal clinically important difference for SF-12 PCS/MCS or ODI.

CONCLUSIONS

In our prospective cohort, there were no significant differences found between WC versus non-WC patients in terms of fusion rates, complications, clinical outcomes, or proportion of patients achieving minimal clinically important difference.

Anterior Lumbar Interbody Fusion in Left-sided Inferior Vena Cava and Right-sided Aortic Arch

Spinal fusion via anterior lumbar interbody fusion (ALIF) can offer symptomatic relief to patients that suffer severe low back pain, radiculopathy, and claudication. However, a detailed working knowledge of the thoracic, abdominal, and lumbar anatomy, particularly of the vasculature, is vital. We report the case of a 68-year-old man who presented with radiculopathy and progressively worsening low back pain despite 9 months of unsuccessful conservative therapy and pain management. Preoperative computed tomography and magnetic resonance imaging revealed a rare anatomical variation, with an anomalous left-sided inferior vena cava and anomalous aorta. The patient was surgically treated with ALIF at L_4,5 and L₅ S₁ via an altered surgical window. Given the anomalous anatomy of the patient, instead of performing the procedure after mobilizing both of the transposed abdominal great vessels, the inferior vena cava and the abdominal aorta, the ALIF was uneventfully performed in the window between these vessels. There were no perioperative or postoperative complications. At 12-week postoperative follow-up, X-ray imaging demonstrated successful implantation of ALIF cages with no recurrence of symptoms. A detailed working knowledge of anatomy is important, particularly if anatomical variations are present. This has implications for preoperative surgical planning, which is integral to the safety and the success of procedures.

Applying the Mini-Open Anterolateral Lumbar Interbody Fusion with Self-Anchored Stand-Alone Polyetheretherketone Cage in Lumbar Revision Surgery

The author retrospectively studied twenty-two patients who underwent revision lumbar surgeries using ALLIF with a self-anchored stand-alone polyetheretherketone (PEEK) cage. The operation time, blood loss, and perioperative complications were evaluated. Oswestry disability index (ODI) scores and visual analog scale (VAS) scores of leg and back pain were analyzed preoperatively and at each time point of postoperative follow-up. Radiological evaluation including fusion, disc height, foraminal height, and subsidence was assessed. The results showed that the ALLIF with a self-anchored stand-alone PEEK cage is safe and effective in revision lumbar surgery with minor surgical trauma, low access-related complication rates, and satisfactory clinical and radiological results.

Oblique Lumbar Interbody Fusion for Revision of Non-union Following Prior Posterior Surgery: A Case Report

We report the case of a 75-year-old lady who presented with a L2-3 non-union 18 months following a L2-3 and L3-4 posterior decompression and transforaminal lumbar interbody fusion. Halo of the L2 pedicle screws on imaging was consistent with a non-union at the L2-3 level. An anterior lumbar interbody fusion (ALIF) approach was originally considered. However, due to the high lumbar approach and patient habitus [body mass index (BMI) > 35], a decision was made to approach the L2-3 level using an oblique technique. This involved dissection anterior to the psoas muscle to access the L2-3 disc space. The psoas, kidney and retroperitoneum were retracted using a Synframe for the oblique trajectory. Removal of the prior trans-foraminal lumbar interbody fusion cage was performed via the oblique approach and insertion of a revised implant. The operation was completed successfully with no perioperative complications noted. Length of stay was 3 days, with the patient achieving rapid pain relief. In the present report, we report the first case using an oblique lumbar interbody fusion (OLIF) approach for revision of a prior posterior fusion non-union at the L2,3 level. The OLIF technique is feasible for revision of a non-union of upper lumbar levels, with satisfactory fusion achieved with acceptable feasibility.

Evolution of Design of Interbody Cages for Anterior Lumbar Interbody Fusion

Anterior lumbar interbody fusion (ALIF) is one of the surgical procedures for the relief of chronic back pain, radiculopathy and neurogenic claudication in patients with degenerative lumbar spine disease that is refractory to conservative therapy, low-grade spondylolisthesis and pseudo arthrosis. Over the past half century, both the surgical techniques and instrumentation required for ALIF have changed significantly. In particular, the designs of ALIF cage and the materials used have evolved dramatically, the common goal being to improve fusion rates and optimize clinical outcomes. The increasing popularity of ALIF is reflected by the increasing abundance of published studies reporting clinical outcomes, surgical techniques and grafting options for ALIF. Developments in cage designs include cylindrical Bagby and Kuslich, cylindrical ray, cylindrical mesh, lumbar-tapered, polyethyl-etherketone cage and integral fixation cages. Biologic implants include bone dowels and femoral ring allografts. Methods for optimization of cage design have included cage dimensions, use of novel composite cage materials and integral fixation technologies. However, the historical development and evolution of cages used for ALIF has not been extensively documented. This article therefore aims to provide an overview of the historical basis for the anterior approach, evolution in design of ALIF cage implants and potential future research directions.

Lumbar interbody fusion: techniques, indications and comparison of interbody fusion options including PLIF, TLIF, MI-TLIF, OLIF/ATP, LLIF and ALIF

Degenerative disc and facet joint disease of the lumbar spine is common in the ageing population, and is one of the most frequent causes of disability. Lumbar spondylosis may result in mechanical back pain, radicular and claudicant symptoms, reduced mobility and poor quality of life. Surgical interbody fusion of degenerative levels is an effective treatment option to stabilize the painful motion segment, and may provide indirect decompression of the neural elements, restore lordosis and correct deformity. The surgical options for interbody fusion of the lumbar spine include: posterior lumbar interbody fusion (PLIF), transforaminal lumbar interbody fusion (TLIF), minimally invasive transforaminal lumbar interbody fusion (MI-TLIF), oblique lumbar interbody fusion/anterior to psoas (OLIF/ATP), lateral lumbar interbody fusion (LLIF) and anterior lumbar interbody fusion (ALIF). The indications may include: discogenic/facetogenic low back pain, neurogenic claudication, radiculopathy due to foraminal stenosis, lumbar degenerative spinal deformity including symptomatic spondylolisthesis and degenerative scoliosis. In general, traditional posterior approaches are frequently used with acceptable fusion rates and low complication rates, however they are limited by thecal sac and nerve root retraction, along with iatrogenic injury to the paraspinal musculature and disruption of the posterior tension band. Minimally invasive (MIS) posterior approaches have evolved in an attempt to reduce approach related complications. Anterior approaches avoid the spinal canal, cauda equina and nerve roots, however have issues with approach related abdominal and vascular complications. In addition, lateral and OLIF techniques have potential risks to the lumbar plexus and psoas muscle. The present study aims firstly to comprehensively review the available literature and evidence for different lumbar interbody fusion (LIF) techniques. Secondly, we propose a set of recommendations and guidelines for the indications for interbody fusion options. Thirdly, this article provides a description of each approach, and illustrates the potential benefits and disadvantages of each technique with reference to indication and spine level performed.