Major vascular injury during anterior lumbar spinal surgery: incidence, risk factors, and management

ALIF vs. posterior fusion for lumbar degenerative disease: comparable efficacy but elevated risk of severe complications-a systematic review and meta-analysis

BACKGROUND

Over the past years, there has been an upward trend in the total number of spinal fusion procedures worldwide. There are many different strategies to perform the lumbar fusion, each with some advantages. Hospital charges for lumbar spinal surgeries also have increased significantly, with great variation in the costs and recommendations of different surgical procedures. There has also been a trend increase in the rate of the use of interbody fusion implants compared to that of traditional decompression surgery, even though the former is known to incur higher costs. Access through the anterior route gained many followers after studies on sagittal balance, and its indication has also increased worldwide. However, this technique presents different patterns of complications from those observed in traditional posterior approaches.

OBJECTIVES

This study aims to determine the safety and efficacy of surgery in managing patients with symptomatic lumbar degenerative diseases by comparing the effectiveness of posterior and anterior approach techniques to treat this condition on patient-related outcomes. We also aimed to investigate the safety of these surgical interventions by including perioperative complication data.

METHODS

A systematic search of multiple online databases was conducted up to August 2024 to identify randomized controlled trials (RCTs) and other high-quality retrospective studies comparing outcomes of anterior lumbar interbody fusion (ALIF) versus posterior fusion techniques (PLF, PLIF, TLIF) in the treatment of degenerative lumbar diseases. The primary outcomes assessed included the Oswestry Disability Index, Visual Analogue Scale, and overall clinical improvement. Secondary outcomes encompassed complications such as mortality, infections, gastrointestinal complications, deep vein thrombosis (DVT), surgical site infections, and the need for blood transfusions, as well as length of hospital stay and operative duration. Pooled effect estimates were calculated and presented as mean differences (MD) with 95% confidence intervals (CI) at the two-year follow-up.

RESULTS

Regarding VAS and ODI, anterior and posterior approaches were similar in analyzing five RCTs. Including retrospective studies, we also found that the length of hospital stay and duration of surgery were comparable between the two approaches. Anterior approaches had a lower rate of patients requiring blood transfusions OR 0,69[0.60,0,80]. Anterior approaches showed higher rates of mortality (0,21%) OR1,33[1.10,1.62], deep vein thrombosis (0,65%) 1.73 [1.35, 2.20], and gastrointestinal complications (4,9%) OR 2.19 [1.73, 2.78].

CONCLUSION

Clinical outcomes measured by VAS and ODI were comparable between anterior and posterior approaches, demonstrating similar efficacy in treating lumbar degenerative diseases. However, the safety profiles varied significantly. Anterior approaches carried higher rates of severe complications, including mortality, DVT, and gastrointestinal events, while posterior techniques were linked to increased blood transfusion needs. Given the elevated risk of severe complications with ALIF, posterior approaches should be prioritized as the first-line option for lumbar degenerative disease.

Vascular injuries and complications in anterior lumbar interbody fusion: an up-to-date review

Vascular injuries during anterior lumbar interbody fusion (ALIF) are reported in the existing literature with an incidence rate ranging from 1% to 24%, predominantly venous lacerations owing to branch vessel avulsions during mobilization and retraction. Arterial injuries, although less frequent, occur at an incidence of 0.45% to 1.5% and are mainly characterized by thromboses; aortic lacerations remain exceptionally rare. L4-L5 and L5-S1 are the two levels associated with the majority of vascular complications. Preoperative 3D CT angiography is paramount and a gold standard, as it illustrates the anatomic variations of the iliolumbar vein, the aorta, and the vena cava bifurcation, providing the surgeon with valuable information regarding operative trajectories. Regarding preventive measures, venous laceration, the most common vascular injury, occurs less frequently when employing nonthreaded interbody grafts such as iliac crest autograft or femoral ring allograft. Also, left iliac artery thrombosis can be decreased intraoperatively by intermittent release of retraction. Managing vascular complications includes compression for bleeding control, Trendeleburg positioning of the patient and venorrhaphy, and the employment of topical clot-forming enhancement and/or hemostatic agents. Although postoperative lower limb duplex ultrasonography can be an effective tool, magnetic resonance venography (MRV) and intravenous catheterization (IVC) remain the gold standards for diagnosing postoperative pelvic vein thrombosis in cases of iliac vein repair after anterior spine surgery. This paper aimed to highlight the incidence of major vascular injury during ALIF surgery, describe predisposing risk factors, and discuss management techniques while highlighting the requirement for more sensitive and factor-specific studies to attain a more profound understanding of the mechanism of vasculature complications during ALIF procedures.

Endovascular repair for thoracic aortic pseudoaneurysm induced by pedicle screw implantation: a case report with 8 years follow-up

BACKGROUND

Pedicle screw instrument surgeries can result in the development of aortic pseudoaneurysm, which is a rare yet potentially severe complication; therefore, the purpose of this work is to describe the case of pseudoaneurysm of the thoracic aorta caused by the severe migration of a pedicle screw after surgery.

CASE PRESENTATION

We herein report a patient who underwent endovascular repair for the pseudoaneurysm of the descending thoracic aorta following thoracic vertebral fixation surgery. A 28-80 mm covered stent was initially inserted through the right femoral artery, and intraoperative aortography revealed a minor extravasation of contrast material. Subsequently, an additional 28-140 mm covered stent was implanted. The patient recovered well during the 8-year follow-up period.

CONCLUSIONS

Vascular complications resulting from spinal surgery are severe and rare, necessitating early diagnosis and intervention.

The Role of Anterior Spine Surgery in Deformity Correction

There are a range of anterior-based approaches to address flexible adult spinal deformity from the thoracic spine to the sacrum, with each approach offering access to a range of vertebral levels. It includes the transperitoneal (L5-S1), paramedian anterior retroperitoneal (L3-S1), oblique retroperitoneal (L1-2 to L5-S1), the thoracolumbar transdiaphragmatic approach (T9-10 to L4-5), and thoracotomy approach (T4-T12). The lumbar and lumbosacral spine is especially favorable for anterior-based approaches given the relative mobility of the peritoneal organs and position of the vasculature.

Specialty Impact on Patient Outcomes: Paving a Way for an Integrated Approach to Spinal Disorders

Spinal surgical procedures are steadily increasing globally due to broad indications of certain techniques encompassing a wide spectrum of conditions, including degenerative spine disorders, congenital anomalies, spinal metastases, and traumatic spinal fractures. The two specialties, neurosurgery (NS) and orthopedic surgery (OS), both possess the clinical adeptness to perform these procedures. With the advancing focus on comparative effectiveness research, it is vital to compare patient outcomes in spine surgeries performed by orthopedic surgeons and neurosurgeons, given their distinct approaches and training backgrounds to guide hospital programs and physicians to consider surgeon specialty when making informed decisions. Our review of the available literature revealed no significant difference in postoperative outcomes in terms of blood loss, neurological deficit, dural injury, intraoperative complications, and postoperative wound dehiscence in procedures performed by neurosurgeons and orthopedic surgeons. An increase in blood transfusion rates among patients operated by orthopedic surgeons and a longer operative time of procedures performed by neurosurgeons was a consistent finding among several studies. Other findings include a prolonged hospital stay, higher hospital readmission rates, and lower cost of procedures in patients operated on by orthopedic surgeons. A few studies revealed lower sepsis rates unplanned intubation rates and higher incidence of urinary tract infections (UTIs) and pneumonia postoperatively among patient cohorts operated by neurosurgeons. Certain limitations were identified in the studies including the use of large databases with incomplete information related to patient and surgeon demographics. Hence, it is imperative to account for these confounding variables in future studies to alleviate any biases. Nevertheless, it is essential to embrace a multidisciplinary approach integrating the surgical expertise of the two specialties and develop standardized management guidelines and techniques for spinal disorders to mitigate complications and enhance patient outcomes.

The anatomical feasibility of anterior intra- and extra-bifurcation approaches to L5-S1: an anatomic study based on lumbar MRI

BACKGROUND CONTEXT

The anterior approach at L5-S1 has many advantages, however, vascular complications are challenging for spinal surgeons who may not be familiar with the variability of vascular anatomy. There are three different anterior approaches (intra-bifurcation approach and extra-bifurcation: left-, and right-sided prepsoas approaches) described in previous studies to respond to the variability of anterior vascular anatomy for reduction in vascular injury, while no guidance for the choice of approach preoperatively.

PURPOSE

To analyze the anatomical feasibility of three anterior approaches to access the L5-S1 disc space according to a practical framework.

STUDY DESIGN

Retrospective study.

PATIENT SAMPLE

Lumbar magnetic resonance imaging (MRI) from patients who visited our outpatient clinic were reviewed, with 150 cases meeting the inclusion criteria.

OUTCOME MEASURES

The following radiographic parameters were measured on axial T2-weighted MRI at the lower endplate of L5 and the upper endplate of S1: width of the vascular corridor, position of the left and right common iliac vein (CIV), and presence of perivascular adipose tissue (PAT). Moreover, we designed a safe line to evaluate the feasibility of left- and right-sided prepsoas approaches. Cases of lumbosacral transitional vertebrae were identified.

METHODS

The feasibility of the intra-bifurcation approach was determined by the width of the vascular corridor, presence of PAT, and the position of the CIV. The feasibility of the prepsoas approach was determined by the relative position of the CIV to the safe line, presence of PAT, and the intersection point of the CIV and vertebral body.

RESULTS

Sixty-eight percent, 64.7%, and 75.3% cases allowed the intra-bifurcation, left-, and right-sided prepsoas approach to L5-S1, respectively. The cases in this study had at least one of three anterior approaches to access L5-S1 disc space, and 74% of cases had more than one anatomical feasibility of anterior approach. The right-sided prepsoas approach was feasible in the majority of cases because of the vertical course of the right CIV with a significantly higher proportion of presence of PAT. Patients with lumbosacral transitional vertebrae (24 cases) may prefer the prepsoas approaches, and only six cases (25.0%) were determined to be feasible for the intra-bifurcation approach.

CONCLUSIONS

Our study proposes a practical framework to determine whether the three different anterior approaches are feasible access at L5-S1. According to the framework, all cases had the anatomical feasibility of using an anterior approach to access L5-S1, and three-fourths of cases had a replaceable anterior approach when encountering intraoperative difficulties.

Extreme Lateral Interbody Fusion as a Feasible Treatment for Thoracolumbar Spondylodiscitis: A Multicenter Belgian Case-Series

BACKGROUND

Spondylodiscitis is, after tissue sampling, initially managed with intravenous antibiotics. In patients with treatment failure, surgical debridement and stabilization is considered. An anterior or posterior approach has already been reported as a successful surgical access, but is associated with a large exposure and a significant morbidity.

METHODS

We present a multicenter Belgian case-series on the use of a minimally invasive extreme lateral interbody fusion procedure with add-on percutaneous pedicle screw fixation for patients with a need for surgical debridement and tissue samples or intractable back pain due to spondylodiscitis. Patient characteristics, microbiology results, antibiotic treatment, pre- and postoperative Visual Analogue Pain Score (VAS) scores, time to bony consolidation, complications and duration of the hospital stay were collected.

RESULTS

Seven patients with one level spondylodiscitis were included. The mean age 64 years with a mean preoperative VAS score of 8.86 ( ± 0.90). Postoperative VAS score significantly decreased to 2.57 (-70.3%, P < 0.001). Mean antibiotic treatment duration was 8 weeks. Median duration of the hospital stay was 14 days. Patients were followed for 1 year. Complete bony consolidation was observed in 6 out of 7 patients after 1 year. One patient had a stable pseudarthrosis.

CONCLUSIONS

These results indicate that extreme lateral interbody fusion topped off with a percutaneous pedicle screw fixation might be a feasible, safe and valuable choice to surgically treat patients with spondylodiscitis with fast and important improvement in VAS. Further prospective research might strengthen the sparsely existing literature of minimally invasive surgery for spondylodiscitis to provide the best possible care.

Lumbar arthroplasty for treatment of primary or recurrent lumbar disc herniation

PURPOSE

Microdiscectomy is the current gold standard surgical treatment for primary lumbar disc herniations that fail non-surgical measures. Herniated nucleus pulposus is the manifestation of underlying discopathy that remains unaddressed with microdiscectomy. Therefore, risk remains of recurrent disc herniation, progression of the degenerative cascade, and on-going discogenic pain. Lumbar arthroplasty allows for complete discectomy, complete direct and indirect decompression of neural elements, restoration of alignment, restoration of foraminal height, and preservation of motion. In addition, arthroplasty avoids disruption of posterior elements and musculoligamentous stabilizers. The purpose of this study is to describe the feasibility of the use of lumbar arthroplasty in the treatment of patients with primary or recurrent disc herniations. In addition, we describe the clinical and peri-operative outcomes associated with this technique.

METHODS

All patients that underwent lumbar arthroplasty by a single surgeon at a single institution from 2015 to 2020 were reviewed. All patients with radiculopathy and pre-operative imaging demonstrating disc herniation that received lumbar arthroplasty were included in the study. In general, these patients were those with large disc herniations, advanced degenerative disc disease, and a clinical component of axial back pain. Patient-reported outcomes of VAS back, VAS leg, and ODI pre-operatively, at three months, one year, and at last follow-up were collected. Reoperation rate, patient satisfaction, and return to work were documented at last follow-up.

RESULTS

Twenty-four patients underwent lumbar arthroplasty during the study period. Twenty-two (91.6%) patients underwent lumbar total disc replacement (LTDR) for a primary disc herniation. Two patients (8.3%) underwent LTDR for a recurrent disc herniation after prior microdiscectomy. The mean age was 40 years. The mean pre-operative VAS leg and back pain were 9.2 and 8.9, respectively. The mean pre-operative ODI was 22.3. Mean VAS back and leg pain was 1.2 and 0.5 at three months post-operative. The mean VAS back and leg pain was 1.3 and 0.6 at one year post-operative. The mean ODI was 3.0 at one year post-operative. One patient (4.2%) underwent re-operation for migrated arthroplasty device which required repositioning. At last follow-up, 92% of patients were satisfied with their outcome and would undergo the same treatment again. The mean time for return-to-work was 4.8 weeks. After returning to work, 89% of patients required no further leave of absence for recurrent back or leg pain at last follow-up. Forty-four percent of patients were pain free at last follow-up.

CONCLUSION

Most patients with lumbar disc herniations can avoid surgical intervention altogether. Of those that require surgical treatment, microdiscectomy may be appropriate for certain patients with preserved disc height and extruded fragments. In a subset of patients with lumbar disc herniation that require surgical treatment, lumbar total disc replacement is an effective option by performing complete discectomy, restoring disc height, restoring alignment, and preserving motion. The restoration of physiologic alignment and motion may result in durable outcomes for these patients. Longer follow-up and comparative and prospective trials are needed to determine how the outcomes of microdiscectomy may differ from lumbar total disc replacement in the treatment of primary or recurrent disc herniation.

Anterior spinal fusion (ALIF/OLIF/LLIF) with lumbosacral transitional vertebra: A systematic review and proposed treatment algorithm

•Key anterior approaches differences in LSTV include vascular (aortic bifurcation/iliocaval confluence), muscular (psoas) and osseus anatomy (inter-crestal tangent/pubic symphysis), when compared to non-LSTV.•There are increased surgical deviations but not significantly greater complications for anterior approaches in LSTV.•Vascular awareness while accessing L45 will be in the presence of a more cephalad ABF and ICC with sacralized L5, and access to the deeper L56 level will be in the presence of a more caudal ABF and ICC in lumbarized S1.

Anterior spine surgery for the treatment of complex spine pathology: a state-of-the-art review

The use of anterior spinal surgery for the treatment of spinal pathology has experienced a dramatic increase over the past decade. Long relegated to treat complicated anterior pathologies it has returned to mainstream spine surgery techniques for all types of conditions, providing a significant boost to the spine surgeons' armamentarium to address a wide variety of types of spinal diseases more effectively. Anterior surgery is useful whenever there is significant spinal pathology that requires direct visualization of the anterior vertebral column to best restore spinal alignment, structural integrity and neurologic function. These pathologies include spinal deformities, tumors, burst fractures, infections, vertebral avascular necrosis, pseudoarthrosis and other miscellaneous indications. Currently available approaches to the spine include transabdominal, paramedian retroperitoneal, lateral oblique retroperitoneal, thoracotomy, and thoracolumbar extensile. Most of the lumbar approaches are now done through a muscle splitting, minimalistic approach that has decreased their morbidity or more recently via tubular approaches, such as lateral lumbar interbody fusions or other ante-psoas approaches. New retractors, instrumentation, hyperlordotic implants, approved biologics and even image guidance for disc preparation and precise implant placement are all recent advances that will hopefully improve surgical outcomes in patients following anterior spinal surgery. Most importantly, these approaches require added expertise and training with a dedicated team consisting of an anteriorly trained spine surgeon working simultaneously with a dedicated vascular surgeon to ensure maximum safety and superior patient outcomes. This state of the review is dedicated to familiarizing practicing spine surgeons with the most commonly used anterior spinal approaches along with cutting-edge instrumentation and fusion techniques to improve their options for the treatment of difficult spinal pathologies.

Biodegradable interbody cages for lumbar spine fusion: Current concepts and future directions

Lumbar fusion often remains the last treatment option for various acute and chronic spinal conditions, including infectious and degenerative diseases. Placement of a cage in the intervertebral space has become a routine clinical treatment for spinal fusion surgery to provide sufficient biomechanical stability, which is required to achieve bony ingrowth of the implant. Routinely used cages for clinical application are made of titanium (Ti) or polyetheretherketone (PEEK). Ti has been used since the 1980s; however, its shortcomings, such as impaired radiographical opacity and higher elastic modulus compared to bone, have led to the development of PEEK cages, which are associated with reduced stress shielding as well as no radiographical artefacts. Since PEEK is bioinert, its osteointegration capacity is limited, which in turn enhances fibrotic tissue formation and peri-implant infections. To address shortcomings of both of these biomaterials, interdisciplinary teams have developed biodegradable cages. Rooted in promising preclinical large animal studies, a hollow cylindrical cage (Hydrosorb™) made of 70:30 poly-l-lactide-co-d, l-lactide acid (PLDLLA) was clinically studied. However, reduced bony integration and unfavourable long-term clinical outcomes prohibited its routine clinical application. More recently, scaffold-guided bone regeneration (SGBR) with application of highly porous biodegradable constructs is emerging. Advancements in additive manufacturing technology now allow the cage designs that match requirements, such as stiffness of surrounding tissues, while providing long-term biomechanical stability. A favourable clinical outcome has been observed in the treatment of various bone defects, particularly for 3D-printed composite scaffolds made of medical-grade polycaprolactone (mPCL) in combination with a ceramic filler material. Therefore, advanced cage design made of mPCL and ceramic may also carry initial high spinal forces up to the time of bony fusion and subsequently resorb without clinical side effects. Furthermore, surface modification of implants is an effective approach to simultaneously reduce microbial infection and improve tissue integration. We present a design concept for a scaffold surface which result in osteoconductive and antimicrobial properties that have the potential to achieve higher rates of fusion and less clinical complications. In this review, we explore the preclinical and clinical studies which used bioresorbable cages. Furthermore, we critically discuss the need for a cutting-edge research program that includes comprehensive preclinical in vitro and in vivo studies to enable successful translation from bench to bedside. We develop such a conceptual framework by examining the state-of-the-art literature and posing the questions that will guide this field in the coming years.

Risk Assessment of Anterior Lumbar Interbody Fusion Access in Degenerative Spinal Conditions

STUDY DESIGN

This was a retrospective cohort study.

OBJECTIVE

Develop an evidence-based preoperative risk assessment scoring system for patients undergoing anterior lumbar interbody fusion (ALIF).

SUMMARY OF BACKGROUND DATA

ALIF may hold advantages over other fusion techniques in sagittal restoration and fusion rates, though it introduces unique risks to vascular and abdominal structures and thus possibly increased risk of operative morbidity.

METHODS

Primary, 1 or 2-level ALIFs were identified in a surgical registry. Baseline characteristics were recorded. Axial magnetic resonance imagings at L4-L5 and L5-S1 were reviewed for vascular confluence/bifurcation or anomalous structures, and measured for operative window size/slope. To assess favorable outcomes, a clinical grade was calculated: (clinical grade=blood loss×operative duration), higher value indicating poorer outcome. To establish a risk scoring system, a base risk score algorithm was established and stratified into 5 categories: high, high to intermediate, intermediate, intermediate to low, and low. Modifiers to base risk score included age, body mass index, operative level, history of bone morphogenic protein use, calcified vasculature, spondylolisthesis grade, working window size and slope, and abnormal vasculature. Modifiers were weighted for contribution to surgical risk. A total risk score was calculated and evaluated for strength of association with clinical outcome grades by Pearson correlation coefficient.

RESULTS

A total of 65 patients were included. Mean clinical outcome grade was 5.6, mean total risk score 21.3±21.5. Multilevel procedures (L4-S1) mean total risk score was 57.3±7.8. L4-L5 mean total risk score was 23.6±5.2; L5-S1 mean total risk score 8.3±6.6. Correlation analysis demonstrated a significant and strong relationship (| r |=0.753; P <0.001) between total risk scores and clinical outcome grades.

CONCLUSION

Calculated ALIF risk scores significantly correlated with operative duration and blood loss. This scoring system represents a potential framework to facilitate clinical decision-making and risk assessment for potential ALIF candidates with degenerative spinal pathologies.

Influence of Vascular Anatomy on the Radiologic Outcomes in Oblique Lateral Interbody Fusion at L5-S1

STUDY DESIGN

This was a retrospective study.

OBJECTIVE

The objective of this study was to evaluate whether the anatomy of the left common iliac vein (LCIV) affects the radiologic outcomes in oblique lateral interbody fusion (OLIF) at L5-S1.

SUMMARY OF BACKGROUND DATA

Upward mobilization and retraction of the LCIV is an essential technique in OLIF at L5-S1. However, mobilization of the LCIV is sometimes difficult and may affect the surgical outcomes in OLIF at L5-S1.

METHODS

This study involved 52 consecutive patients who underwent OLIF at L5-S1 and had >1-year regular follow-up. The configuration of LCIV on preoperative axial magnetic resonance images of the lumbar spine was categorized into 3 types according to the difficulty of mobilization: type I (no requirement for mobilization), type II (potentially easy mobilization), and type III (potentially difficult mobilization). Radiologic parameters included anterior/posterior disk heights (ADH/PDH), disk angle (DA), cage migration, cage subsidence, cage position, and fusion rate at L5-S1. Intraoperative/perioperative events associated with OLIF at L5-S1 were reviewed. Radiologic outcomes among the LCIV types were compared.

RESULTS

There were 19 men and 33 women with a mean age of 62.8±9.7 years. The mean follow-up duration was 24.8±15.5 months. The LCIV anatomy was type I in 25 (48.1%) patients, type II in 14 (26.9%), and type III in 13 (25.0%). The mean ADH increased from 7.0±4.7 to 16.9±4.1 mm at the last follow-up (P<0.001), and the mean PDH increased from 2.7±1.7 to 4.9±1.6 mm (P<0.001). The mean DA increased from 5.4±5.4 to 16.9±6.5 degrees (P<0.001). There were no significant differences in ADH, PDH, and DA at the last follow-up among the LCIV types. Two (3.8%) major and 2 (3.8%) minor LCIV injuries were identified, all of which had a type III LCIV.

CONCLUSIONS

OLIF at L5-S1 showed favorable radiologic outcomes regardless of the LCIV anatomy. However, type III LCIV patients had a high rate of intraoperative vascular injury.

Vascular Injury in Elective Anterior Surgery of the Lumbar Spine: A Narrative Review

The incidence of anterior lumbar surgery is increasing as the population is aging. Although adverse events regarding vasculature injury are uncommon, several have been described in the current literature. Complications can be categorized based on the time of occurrence, more specifically intraoperative or postoperative, but also regarding the nature of vascular damage such as thrombosis, occlusion, or rupture. The rate of complications is higher in the setting of revision anterior surgery than with primary anterior lumbar surgery. Moreover, the incidence of revision anterior surgery is also increasing in contrast to the past. Through this narrative review, an effort is made for a thorough understanding of the complications associated with anterior lumbar surgery, which will aid in the prevention, recognition, and management of this rare complication.

Ureteral injury following anterior thoracolumbar spinal instrumented fusion for adolescent idiopathic scoliosis: a case report with CT angiography analysis of surgically relevant anatomy

PURPOSE

To report a rare ureteral injury following anterior spinal fusion for adolescent idiopathic scoliosis (AIS) that resulted in complete nephrectomy and to delineate the anatomical relationship between the proximal ureter and the anterior lumbar spine based on CT angiography (CTA).

METHODS

Thoracolumbar spine CTAs of children with AIS were reviewed. We measured the following relationships to the ureters: lateral-most aspect of vertebral body, anterior psoas at intervertebral disc/vertebral body levels, and lateral psoas at vertebral body level. Spine level at which the renal arteries originated from the aorta was identified. Distance from origin to corresponding vertebral body/intervertebral disc also was measured.

RESULTS

Forty-one girls and seven boys (mean age 12 years, range 7-18) were analyzed. Scoliosis lumbar convexity was left 94% and right 6%. From L1 to L4, ureter was identified within 1-2 cm of vertebral body. Distance between ureter and vertebral body and ureter and anterior psoas at intervertebral disc/vertebral body levels was less on left vs. right from L1 to L4 (p < 0.0001). Distance between ureter and lateral psoas was less on left vs. right from L1 to L2 (p = 0.0205; p = 0.0132) and greater on left vs. right from L3 to L4 (p = 0.0022; p = 0.0076). Renal artery originated at L1/L2 in > 50%. There was no difference in distance from renal artery origin to vertebral body/intervertebral disc (p = 0.4764).

CONCLUSION

Ureteral injury is a potentially morbid complication of anterior spine surgery. Injury can occur secondary to disrupted blood supply and mechanical tissue damage. Surgeons must clearly understand the juxta-spinal anatomy to limit dissection and modify retraction to reduce risk.

LEVEL OF EVIDENCE

Level IV.

Surgical safe zones for oblique lumbar interbody fusion of L1-5: A cadaveric study

To evaluate the operating range and morphology of the surgical safe zone for oblique lumbar interbody fusion (OLIF). Twenty embalmed full-torso cadaveric specimens were dissected. The oblique corridor and the distance between adjacent lumbar arteries were measured in a static state and with psoas major retraction. The morphology and size of the safe zone for OLIF and the location of the lumbar sympathetic trunk were also recorded. The oblique corridor of the L1-L5 segments was significantly greater in the retracted state than in the static state (p < 0.05). With psoas major retraction, the distances between adjacent lumbar arteries at L1-4 were significantly greater (p < 0.05) than those in the static state. The lumbar sympathetic trunk is just located in the safe zone and travels downward adjacent to the psoas major. The shape of the safe zone for OLIF was approximately an oblique upward parallelogram at L1/2 and L2/3, an isosceles trapezoid at L3/4, and an irregular quadrangle or triangle at L4/5. The safe zone for OLIF at L1/2, L2/3, and L3/4 was significantly larger during retraction than in the static state (p < 0.05). On the lateral side of the lumbar spine there is a natural surgical safe zone for OLIF, which can provide a sufficient operating space. The safe zone has a certain morphological pattern in L1-5 segments and psoas major retraction can significantly enlarge it.

Development of machine learning and natural language processing algorithms for preoperative prediction and automated identification of intraoperative vascular injury in anterior lumbar spine surgery

BACKGROUND

Intraoperative vascular injury (VI) may be an unavoidable complication of anterior lumbar spine surgery; however, vascular injury has implications for quality and safety reporting as this intraoperative complication may result in serious bleeding, thrombosis, and postoperative stricture.

PURPOSE

The purpose of this study was to (1) develop machine learning algorithms for preoperative prediction of VI and (2) develop natural language processing (NLP) algorithms for automated surveillance of intraoperative VI from free-text operative notes.

PATIENT SAMPLE

Adult patients, 18 years or age or older, undergoing anterior lumbar spine surgery at two academic and three community medical centers were included in this analysis.

OUTCOME MEASURES

The primary outcome was unintended VI during anterior lumbar spine surgery.

METHODS

Manual review of free-text operative notes was used to identify patients who had unintended VI. The available population was split into training and testing cohorts. Five machine learning algorithms were developed for preoperative prediction of VI. An NLP algorithm was trained for automated detection of intraoperative VI from free-text operative notes. Performance of the NLP algorithm was compared to current procedural terminology and international classification of diseases codes.

RESULTS

In all, 1035 patients underwent anterior lumbar spine surgery and the rate of intraoperative VI was 7.2% (n=75). Variables used for preoperative prediction of VI were age, male sex, body mass index, diabetes, L4-L5 exposure, and surgery for infection (discitis, osteomyelitis). The best performing machine learning algorithm achieved c-statistic of 0.73 for preoperative prediction of VI (https://sorg-apps.shinyapps.io/lumbar_vascular_injury/). For automated detection of intraoperative VI from free-text notes, the NLP algorithm achieved c-statistic of 0.92. The NLP algorithm identified 18 of the 21 patients (sensitivity 0.86) who had a VI whereas current procedural terminologyand international classification of diseases codes identified 6 of the 21 (sensitivity 0.29) patients. At this threshold, the NLP algorithm had a specificity of 0.93, negative predictive value of 0.99, positive predictive value of 0.51, and F1-score of 0.64.

CONCLUSION

Relying on administrative procedural and diagnosis codes may underestimate the rate of unintended intraoperative VI in anterior lumbar spine surgery. External and prospective validation of the algorithms presented here may improve quality and safety reporting.

Comparison of surgical outcomes between oblique lateral interbody fusion (OLIF) and anterior lumbar interbody fusion (ALIF)

OBJECTIVE

Although oblique lateral interbody fusion (OLIF) utilizes the similar approach in anterior lumbar interbody fusion (ALIF), OLIF is essentially a lateral lumbar interbody fusion (LLIF). Therefore, OLIF may have advantages in LLIF that the lateral cage can achieve greater restoration of the disc height and angle. We aimed to compared the surgical outcomes between OLIF and ALIF.

METHODS

This study involved 47 consecutive patients who underwent a single-level OLIF and 45 consecutive patients who underwent a single-level ALIF at L2-L5 levels. Radiological measurements included the changes of anterior/posterior disc height, coronal/sagittal disc angle, foramen cross-sectional area (CSA), cage position from the anterior margin of the lower vertebra, fusion rate, and cage subsidence using the serial radiographs and computed tomography preoperatively and at the postoperative 1-year follow-up. Clinical outcomes were assessed by visual analog scale (VAS) for back/leg pain, Oswestry disability index (ODI), and the occurrence of perioperative complications.

RESULTS

The baseline radiological and clinical parameters were similar between the OLIF and ALIF groups (all P > 0.05). At postoperative 1 year, the mean anterior disc height was higher in the OLIF group than the ALIF group (11.4 ± 1.9 mm vs. 9.6 ± 2.6 mm, P = 0.021). The mean sagittal disc angle was also greater in the OLIF group than the ALIF group (10.9 ± 4.4° vs. 8.9 ± 5.8°, P < 0.001). The mean cage position was 5.8 ± 2.1 mm in the OLIF group and 8.7 ± 2.3 mm in the ALIF group (P <  0.001). There was no difference in the postoperative changes of coronal disc angles, foramen CSA, fusion rate, cage subsidence, VAS for back/leg pain, ODI, and the occurrence of perioperative complications between the OLIF and ALIF groups (all P > 0.05).

CONCLUSIONS

OLIF showed a greater increase in disc height and segmental lordosis than ALIF with comparable complications. OLIF is a meaningful progress from ALIF.

The Feasibility of Anterior Spinal Access: The Vascular Corridor at the L5-S1 Level for Anterior Lumbar Interbody Fusion

STUDY DESIGN

Cross-sectional study.

OBJECTIVE

To analyze the feasibility of anterior spinal access to the vascular corridor at the L5-S1 junction, by evaluating three crucial anatomical landmarks. This provides a framework for risk-stratification for the clinician during preoperative evaluation.

SUMMARY OF BACKGROUND DATA

The anterior lumbar interbody fusion (ALIF) offers many advantages for fusion at the L5-S1 junction. However, the variant iliac vasculature may preclude safe anterior access.

METHODS

Five hundred magnetic resonance imaging (MRI) images of the L5-S1 level were identified, with 379 meeting inclusion criteria. We graded the anterior access into three grades, namely, easy, advanced, or difficult by looking at three important anatomical landmarks-the vascular corridor (narrow if ≤25 mm, medium if 25-35 mm [inclusive], and wide if >35 mm), the left common iliac vein (LCIV) location (grades A-D based on the relative position of the LCIV to the L5-S1 disc space), and the presence or absence of a fat plane.

RESULTS

Our results showed that 43.27% of the patients had wide corridor for the anterior access, 19.26% of patients had no fat plane, and 7.65% had a LCIV that extended past the midline of the disc (Grade C, D: >50%). By combining these three factors, 37.20% would have easy anterior access, while a minority (1.85%) would have a difficult anterior access.

CONCLUSION

The ALIF at L5-S1 offers significant benefits to the patient. The surgeon should be aware of the dangers in an anterior access by looking at three crucial factors to determine whether the access is easy, advanced, or difficult. Patients with a difficult access should be attempted by experts, vascular access surgeons, or consider an alternative approach to L5-S1.Level of Evidence: 3.

Postoperative adverse events secondary to iatrogenic vascular injury during anterior lumbar spinal surgery

BACKGROUND

Anterior lumbar spine surgery (ALSS) requires mobilization of the great vessels, resulting in a high risk of iatrogenic vascular injury (VI). It remains unclear whether VI is associated with increased risk of postoperative complications and other related adverse outcomes.

PURPOSE

The purpose of this study was to (1) assess the incidence of postoperative complications attributable to VI during ALSS, and (2) outcomes secondary to VI such as procedural blood loss, transfusion of blood products, length of stay (LOS), and in hospital mortality.

STUDY DESIGN

Retrospective propensity-score matched, case-control study at 2 academic and 3 community medical centers, PATIENT SAMPLE: Patients 18 years of age or older, undergoing ALSS between January 1st, 2000 and July 31st, 2019 were included in this analysis.

OUTCOME MEASURES

The primary outcome was the incidence of postoperative complications attributable to VI, such as venous thromboembolism, compartment syndrome, transfusion reaction, limb ischemia, and reoperations. The secondary outcomes included estimated operative blood loss (milliliter), transfused blood products, LOS (days), and in-hospital mortality.

METHODS

In total, 1,035 patients were identified, of which 75 (7.2%) had a VI. For comparative analyses, the 75 VI patients were paired with 75 comparable non-VI patients by propensity-score matching. The adequacy of the matching was assessed by testing the standardized mean differences (SMD) between VI and non-VI group (>0.25 SMD).

RESULTS

Two patients (2.7%) had VI-related postoperative complications in the studied period, which consisted of two deep venous thromboembolisms (DVTs) occurring on day 3 and 7 postoperatively. Both DVTs were located in the distal left common iliac vein (CIV). The VI these patients suffered were to the distal inferior vena cava and the left CIV, respectively. Both patients did not develop additional complications in consequence of their DVTs, however, did require systemic anticoagulation and placement of an inferior vena cava filter. There was no statistical difference with the non-VI group where no instances (0%) of postoperative complications were reported (p=.157). No differences were found in LOS or in hospital mortality between the two groups (p=.157 and p=.999, respectively). Intraoperative blood loss and blood transfusion were both found to be higher in the VI group in comparison to the non-VI group (650 mL, interquartile range [IQR] 300-1400 vs. 150 mL, IQR 50-425, p≤.001; 0 units, IQR 0-3 vs. 0 units, IQR 0-1, p=.012, respectively).

CONCLUSION

This study found a low number of serious postoperative complications related to VI in ALSS. In addition, these complications were not significantly different between the VI and matched non-VI ALSS cohort. Although not significant, the found DVT incidence of 2.7% after VI in ALSS warrants vigilance and preventive measures during the postoperative course of these patients.

Aortic injury in spine surgery……What a spine surgeon needs to know

Aortic injury is a rare, yet underreported and underestimated complication of spine surgery. Anatomical relation between the aorta and the spine changes under physiological (positional) as well as pathological (deformity) conditions, which puts the aorta at risk of injury during spine surgery. Clinical presentation of aortic injury ranges from asymptomatic perforation of the aorta to acute fatal bleeding. Although several diagnostic methods have been reported, CT-angiography remains an important diagnostic study. Several advancements in the open and the endovascular surgical management have been reported to be successfully used in the management of aortic injury following spine surgery. Management approach of malpositioned screws abutting the aorta is still controversial. Anatomical knowledge and understanding of the previously reported mechanisms of aortic injury are important to be integrated in the preoperative planning process. If the complication occurs, time-to- recognition and to-appropriate-management are important factors for predicting mortality. If unrecognized and untreated in the acutely injured patients, mortality can approach 100%.

Using an Extreme Lateral Interbody Fusion (XLIF) in Revising Failed Transforaminal Lumbar Interbody Fusion (TLIF) With Exchange of Cage

Minimally invasive techniques have gained popularity in spine surgery in recent years. Extreme lateral interbody fusion (XLIF) is one of these techniques. The rapid increase in the use of this approach in either primary or revision surgeries is related to its several advantages including less operative time, less blood loss and reduced length of hospital stay with fast recovery. We report a case of a failed transforaminal lumbar interbody fusion (TLIF) in L4-L5 level, one year after the primary procedure with persistent pain due to failed fusion. Underwent revision, by using XLIF with the removal of old cage and exchange with new large cage. Revision of failed interbody fusion can be achieved through anterior, posterior or lateral approach. The decision to proceed with either method depends on several factors, including previous surgeries, fibrosis and risk of neurovascular injury and surgeon's preference. XLIF approach should be considered in revision surgeries of failed interbody fusion. As it can provide several advantages compared to anterior or posterior approaches, in terms of better fusion rates and lower risk of neurovascular injuries by avoiding the use of the previous passage.

Variations in the position of the aorta and vertebral safe zones in supine, prone, and lateral decubitus for adolescent idiopathic scoliosis

PURPOSE

Analyze the modifications in the "safe zones" of T4-L4 vertebral bodies relative to aorta according to patient positioning, as well as in the relationship between the aorta and the vertebrae.

METHODS

Patients with adolescent idiopathic scoliosis who underwent surgical treatment during 2017 were included. Preoperative whole spine MRI in supine, prone, and LD positions was performed. The safe zone right (SZR) was defined as the angle formed between X-axis (0º) and a line connecting the origin and the edge of the aorta, and the safe zone left (SZL) was the angle between the edge of the aorta to 180º (X-axis).

RESULTS

A total of 21 patients were studied, median age was 15.2 years, and 71.4% were female. The mean SZR lied from 0°-86.1º at T4 to 0°-76.9º at L4 in supine, from 0°-84.05º at T4 to 0º-78.5º at L4 in prone, and from 0° to 91.75º at T4 to 0°-80.4º at L4 in LD. While the mean SZL was located from 155.4º-180º at T4 to 107.9º-180º at L4 in supine, from 134°-180° at T4 to 103.9°-180° at L4 in prone, and from 143.8º-180º at T4 to 106º-180º at L4 in LD. Statistically significant differences were found almost at all levels when comparing supine versus prone and LD.

CONCLUSIONS

Patient positioning during spinal surgery significantly modifies T4-L4 vertebral safe zones relative to aorta. These variations should be taken into account when analyzing an MRI performed in supine if the patient is undergoing surgery in a different position, to avoid vascular-related injuries.

The Safety and Efficacy of Stand-Alone Lateral Lumbar Interbody Fusion for Adjacent Segment Disease in a Cohort of 44 Patients

BACKGROUND

A mainstay of treatment for symptomatic adjacent segment disease (ASD) has consisted of revision with posterior decompression and fusion. This carries significant morbidity and can be technically difficult. An alternative is stand-alone lateral lumbar interbody fusion (LLIF), which may avoid complications associated with revision surgery. We describe the largest cohort of patients treated with LLIF for ASD to our knowledge.

METHODS

We conducted a retrospective cohort study on all patients who underwent transpsoas LLIF for ASD at a single academic center between 2012 and 2019. Postoperative improvement was measured using the Visual Analog Scale (VAS) and the Oswestry Disability Index (ODI).

RESULTS

Forty-four patients who underwent LLIF for ASD were identified. Median age was 65 years. Median time from index surgery to ASD development was 78 months. Median levels fused via LLIF was 1. Our median follow-up was 358 days. At follow-up, the median VAS back pain score was 0 (mean, 0.884), median VAS leg pain score was 1 (mean, 0.953), and median ODI was 8. The median improvement for VAS back pain was 8, for VAS leg pain was 6, and for ODI was 40. No patients suffered new neurologic symptoms postoperatively. Of the 17 patients who initially presented with non-pain neurologic symptoms, 8 (47.1%) experienced complete resolution of symptoms, and 5 (29.4%) experienced only some improvement.

CONCLUSIONS

To our knowledge, this is the largest cohort study of patients to date evaluating stand-alone LLIF for ASD. Our patient outcomes show it is safe and effective with low risk of morbidity.

Clinical experience of extreme lateral interbody fusion in the treatment of lumbar spondylodiscitis

Introduction

Up to now, there were few studies on extreme lateral interbody fusion (XLIF) surgery for lumbar spondylodiscitis. This study was aimed to evaluate clinical effectiveness and provide more information for XLIF in the treatment of lumbar spondylodiscitis.

Methods

We retrospectively collected cases of XLIF for the treatment of lumbar spondylodiscitis from September 2017 to February 2020. There were 8 cases of non-specific infection of lumbar spine, 4 cases of lumbar tuberculosis, and 1 case of lumbar brucellosis. Basic information, antibiotic application, and inflammatory index were collected before and after surgery. Clinical effectiveness was evaluated at baseline and in 3, 6, and 12 months after the surgery with visual analog scale (VAS) and Oswestry disability index (ODI). The comparison of the indicators before and after the operation was performed by repeated measures analysis of variance.

Results

The average intraoperative blood loss and operation time was 70mL and 99.23 min, respectively. The study consisted of 13 cases with single segment operation. The average follow-up time was 16.54 months. No sign of recurrence of spondylodiscitis occurred at last follow-up. Postoperative VAS and ODI were significantly decreased after the operation. No major blood vessels, nerves, or organ damage occurred during the perioperative period.

Conclusion

XLIF has shown good clinical effectiveness in the treatment of lumbar spondylodiscitis with advantages of less bleeding and less tissue damage in the present study. More multi-center prospective comparative studies are needed to further verify the clinical effectiveness of this procedure in lumbar spondylodiscitis.

Lumbar Spinal Fusion Using Lateral Oblique (Pre-psoas) Approach (Review)

Lumbar spinal fusion is one of the most common operations in spinal surgery. For its implementation, anterolateral (pre-psoas) approach (oblique lumbar interbody fusion, OLIF) is now increasingly used due to its high efficacy and safety. However, there is still little information on the clinical and radiological results of using this technique.

The aim of the study was to analyze the safety and efficacy of OLIF in the treatment of lumbar spine disorders as presented in the literature.

Treatment of Lumbosacral Tuberculosis with Significant Vertebral Body Loss Using Single-Stage Posterior Surgical Management with a Structural Autograft Combined with a Titanium Mesh Cage

OBJECTIVE

Treatment of lumbosacral tuberculosis is still controversial. In our study, we assessed the efficacy and feasibility of single-stage posterior debridement, interbody fusion using a structural autograft combined with a titanium mesh cage, and posterior instrumentation for the treatment of lumbosacral tuberculosis with significant vertebral body loss.

METHODS

From May 2011 to June 2018, 15 patients with lumbosacral tuberculosis with significant vertebral body loss had undergone single-stage posterior debridement, interbody fusion using a structural autograft combined with a titanium mesh cage, and posterior instrumentation. The pre- and postoperative lumbosacral angle, visual analog scale score, erythrocyte sedimentation rate, C-reactive protein, and neurological status were assessed.

RESULTS

Surgery was successful for all patients, and no patient experienced tuberculosis recurrence during an average follow-up period of 27.3 months (range, 12-60 months). After surgery, the erythrocyte sedimentation rate and C-reactive protein for all patients had returned to normal within 3 months. At the final follow-up examination, the neurological status had improved in all patients who had had neurological deficits preoperatively. The mean preoperative lumbosacral angle was 12.6° (range, 6.7°-17.9°), and had increased to 27.7° (range, 24.3°-34.6°) after surgery. The average lumbosacral angle was 26.4° (range, 22.1°-32.3°), with an average loss of 1.4° (range, 0.6°-2.3°) at the final follow-up visit.

CONCLUSIONS

The combination of single-stage posterior debridement, interbody fusion using structural autografts with a titanium mesh cage, and posterior instrumentation is an effective and safe option for the treatment of lumbosacral tuberculosis with significant vertebral body loss.

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.

Use of thoracic stent grafts to control major iliac vein bleeding

Major venous bleeding is a feared complication during abdominal surgery. Management usually consists of open repair or ligation, despite technically demanding surgical exposure. We present two cases of major iliac vein hemorrhage during abdominal surgery that were controlled by using thoracic stent grafts.

Iliocava junction to L4-L5 disc anatomical relationship in L5-S1 isthmic spondylolisthesis

BACKGROUND

Anterior lumbar interbody fusion finds a place in L5-S1 isthmic spondylolisthesis (ISPL) treatment. Extension of this arthrodesis at L4-L5 level is sometimes required. Anterior approach of the L4L5 disc is considered difficult due to the anatomical relationship between the iliocava junction (ICJ) and the spine.

HYPOTHESIS

Does the lumbosacral deformation induced by ISPL allows anterior approach of L4-L5 disc between the iliac?

STUDY DESIGN

Retrospective radiographic analysis of consecutive patients.

METHODS

This retrospective imaging study of a continuous series of 97 patients treated for an L5-S1 ISPL involved radiological parameters specific to ISPL and pelvic-sagittal balance. The distance between the ICJ and the L4 lower endplate was measured in millimeters. The factors influencing this distance were sought in order to identify a predictive model of high ICJ.

RESULTS

The ICJ took a cranial position with respect to the L4-L5 disc with an average distance of 1.8mm±16.4. This distance was statistically higher in the case of high-grade ISPL (p<0.01). The high ICJ position was correlated with a high Taillard index (r=0.39; CI_95% [0.13; 0.61]; p<.001) and a low lumbar-sacral angle (LSA) (r=-0.33; CI_95% [-0.56; -0.06]; p<0.01). Among the parameters specific to spino-pelvic statics, pelvic incidence, pelvic tilt and lumbar lordosis had similar correlations (r>0.30).

CONCLUSION

ISPL induces a geometric deformation of the lumbosacral hinge which modifies its anatomical relations with the ICJ. The anterior approach technique of L4-L5 disc in the presence of an L5-S1 ISPL is possible between the iliac veins for the large displacement and low LSA forms.

LEVEL OF EVIDENCE

IV, retrospective analysis.

Psoas Hematoma and Late Femoral Nerve Palsy After Extreme Lateral Interbody Fusion and Posterior Spinal Fusion with Instrumentation: A Case Report

Introduction

Psoas hematoma is an uncommon complication following spinal surgeries. It has been reported in both extreme lateral interbody fusion (XLIF) and posterior spinal fusion with instrumentation. Minimally invasive techniques are gaining popularity in recent years due to the appealing advantages of reduced operative time, blood loss, hospital stay, and faster recovery.

Case Presentation

We are presenting a case of a 77-year-old male with chronic low back pain, diagnosed to have multilevel degenerative disc disease with central and foraminal disc protrusion at L2-L3, L3-L4, L4-L5 with secondary spinal stenosis, underwent XLIF at L3-L4, L4-L5 and then 2nd stage with posterior L3-L5 fusion with pedicle screws. On the fourth day post-operatively, the patient had flank pain and dropping hemoglobin with femoral nerve palsy symptoms, a CT scan revealed a large psoas hematoma. Conservative management was decided on; a follow-up CT scan and examination showed complete resolution of the hematoma and femoral nerve recovery.

Discussion

The approach to iliopsoas hematoma post spinal surgeries remains controversial. Iliopsoas hematoma should be suspected in any patients post spinal surgeries even with delayed presentations. The decision to proceed with either surgical intervention or conservative management depends on multiple factors, including patient hemodynamic status, progression of collection and femoral nerve palsy.

Conclusion

The exact cause of iliopsoas hematoma post different spinal surgery approaches remains vague. In our opinion, other causes including pre- and post-operative anticoagulants should be investigated. Rushing to drain iliopsoas hematomas in case of femoral nerve palsy might not be the ideal option. Instead, monitoring patient responses to resuscitation and taking a watch and wait approach for femoral nerve palsy might be the proper approach.

The impact of obesity on perioperative complications in patients undergoing anterior lumbar interbody fusion

OBJECTIVE

Anterior approaches to the lumbar spine provide wide exposure that facilitates placement of large grafts with high fusion rates. There are limited data on the effects of obesity on perioperative complications.

METHODS

Data from consecutive patients undergoing anterior lumbar interbody fusion (ALIF) from 2007 to 2016 at a single academic center were analyzed. The primary outcome was any perioperative complication. Complications were divided into those occurring intraoperatively and those occurring postoperatively. Multivariate logistic regression was used to assess the association of obesity and other variables with these complications. An estimation table was used to identify a body mass index (BMI) threshold associated with increased risk of postoperative complication.

RESULTS

A total of 938 patients were identified, and the mean age was 57 years; 511 were females (54.5%). The mean BMI was 28.7 kg/m2, with 354 (37.7%) patients classified as obese (BMI ≥ 30 kg/m2). Forty patients (4.3%) underwent a lateral transthoracic approach, while the remaining 898 (95.7%) underwent a transabdominal retroperitoneal approach. Among patients undergoing transabdominal retroperitoneal ALIF, complication rates were higher for obese patients than for nonobese patients (37.0% vs 28.7%, p = 0.010), a difference that was driven primarily by postoperative complications (36.1% vs 26.0%, p = 0.001) rather than intraoperative complications (3.2% vs 4.3%, p = 0.416). Obese patients had higher rates of ileus (11.7% vs 7.2%, p = 0.020), wound complications (11.4% vs 3.4%, p < 0.001), and urinary tract infections (UTI) (5.0% vs 2.5%, p = 0.049). In a multivariate model, age, obesity, and number of ALIF levels fused were associated with an increased risk of postoperative complication. An estimation table including 19 candidate cut-points, odds ratios, and adjusted p values found a BMI ≥ 31 kg/m2 to have the highest association with postoperative complication (p = 0.012).

CONCLUSIONS

Obesity is associated with increased postoperative complications in ALIF, including ileus, wound complications, and UTI. ALIF is a safe and effective procedure. However, patients with a BMI ≥ 31 kg/m2 should be counseled on their increased risks and warrant careful preoperative medical optimization and close monitoring in the postoperative setting.

Intraoperative inadvertent piercing of the aortic arch: case report

Aortic injury is a rarely encountered complication of spinal surgery. The authors report a case of a 32-year-old woman with a T3 tumor who experienced an intraoperative aortic arch injury during T3 spondylectomy. The patient was successfully treated with no postoperative neurological deficits.

Treatment of lumbosacral tuberculosis by anterior internal fixation combined with computed tomography angiography

OBJECTIVE

This study aims to examine the iliac vascular space in patients with lumbosacral tuberculosis and to evaluate the feasibility of anterior internal fixation for lumbosacral tuberculosis.

METHODS

A retrospective analysis was performed in 36 patients with lumbosacral tuberculosis. The preoperative three-dimensional computed tomography angiography images were analyzed for anatomical parameters.

RESULTS

There were large variations among the anterior lumbosacral iliac vessels. Predominantly, the left iliac vein and the right iliac artery formed the two borders of the triangular iliac vascular space in the coronal plane. The mean distance between the iliac vessels straddle point and the inferior endplate of L5 was 15.01 ± 15.08 mm. In the sagittal plane, presacral abscess increased the distance between the posterior iliac vessel and the anterior vertebra. The distances on the left and right sides were 9.94 ± 6.03 and 10.15 ± 5.46 mm, respectively, at the inferior endplate of L5 and were 11.90 ± 6.97 and 11.68 ± 5.52 mm, respectively, at the superior endplate of S1.

CONCLUSIONS

The space on sagittal plane occupied by presacral abscess may push forward the vessels and therefore provide opportunities for anterior internal fixation.

Surgical Management of L5-S1 Spondylodiscitis on Previously Documented Isthmic Spondylolisthesis: Case Report and Review of the Literature

Background

Although lumbar isthmic spondylolisthesis is frequent in the Caucasian population, its association with spondylodiscitis is extremely rare. Case Description. The authors reported the case of a 44-year-old patient affected by pyogenic spondylodiscitis on previously documented isthmic spondylolisthesis at the L5-S1 level. The patient was surgically treated by circumferential arthrodesis combining anterior lumbar interbody fusion (ALIF), followed by L4-S1 percutaneous osteosynthesis using the same anesthesia. Appropriate antibiotherapy to methicillin-susceptible Staphylococcus aureus, found on the intraoperative samplings, was then delivered for 3 months, allowing satisfactory evolution on the clinical, biological, and radiological levels. Discussion. This is the first case report of spondylodiscitis affecting an isthmic spondylolisthesis surgically treated by circumferential arthrodesis. In addition to providing large samplings for analysis, it confirms the observed evolution over the past 30 years in modern care history of spondylodiscitis, increasingly including surgical treatment with spinal instrumentation, thus avoiding the need of an external immobilization. Care must nonetheless be exercised in performing the ALIF because of the inflammatory tissue increasing the risk of vascular injury.

Conclusion

Spondylodiscitis occurring on an L5-S1 isthmic spondylolisthesis can be safely managed by circumferential arthrodesis combining ALIF then percutaneous osteosynthesis in the same anesthesia, obviously followed by appropriate antibiotherapy.

Improving blood product utilization at an ambulatory surgery center: a retrospective cohort study on 50 patients with lumbar disc replacement

Background

There is minimal literature discussing anterior lumbar spine surgery in ambulatory surgery centers (ASCs). The main concern with the anterior approach to the lumbar spine is the potential for injury to great vessels. In our facility, there are two units of crossmatched blood available in addition to cell saver during the procedure. We retrospectively looked at 50 cases of lumbar total disc arthroplasty (TDA) in our ASC to determine utilization of blood products.

Methods

Medical records of 50 consecutive patients who underwent a lumbar TDA at a single ASC were reviewed. Surgeries completed at the ASC were all transferred from the post anesthesia care unit to an attached convalescence care center which allows up to 3 days of observation. Patients who had either a 1 or 2 level lumbar TDA were included in the study. Data consisting of demographics, American Society of Anesthesiologist Physical Status Classification System, length of stay, estimated blood loss, cell saver volume, transfusion, perioperative and postoperative complications were recorded. Preoperative, perioperative and postoperative medical records were reviewed.

Results

Medical records of 50 consecutive patients were reviewed. The mean age was 40.86 ± 9.45. Of these, 48 (96%) had a 1-level lumbar TDA, 1(2%) had a 2-level lumbar TDA, 1 (2%) had a lumbar TDA at L4/5 and an anterior lumbar interbody fusion at L5/S1. There were no mortalities; no patient had recorded perioperative complications. No patients received allogeneic blood transfusion, 4 (8%) were re-transfused with cell saver (2 receiving approximately 400 ml and 2 receiving approximately 200 ml of re-transfused blood). All 50 (100%) were discharged home in stable condition. We had 30-day follow-up data on 35 of 50 patients. Of the 35 patients reviewed, three (8.5%) of the patients were readmitted to the hospital. One additional patient was seen in the emergency department and discharged home after negative testing. No patient was readmitted for post-operative anemia.

Conclusion

The routine use of both cell saver and crossmatched blood in the operating suite for lumbar TDA may be an over-utilization of healthcare resources. In our review of 50 patients, we had no need for transfusion of allogeneic packed red blood cells (PRBCs) and only four of the 50 patients had enough blood output for re-transfusion from the cell saver. This opens the conversation for alternatives to crossmatched PRBCs being held in the operating room. Such alternatives may be the use of cell salvage, only type O blood in a cooler for each patient or keeping type O blood on constant hold in ASCs.

Anatomical Evaluation of Lumbar Arteries for Lateral Lumbar Interbody Fusion with Magnetic Resonance Imaging

Introduction

Lateral lumbar interbody fusion (LLIF) is becoming a more common surgical treatment option for adult degenerative lumbar conditions. LLIF is a mini-open access technique with wound retractors, and postoperative hematoma due to segmental vessels injury is reported. Thus, it is considered that there is a need to conduct detailed preoperative examinations to identify where the lumbar vessels are. As far as we know, there are only a few studies investigating the location of the lumbar arteries. This study evaluates the anatomical position of lumbar arteries using magnetic resonance imaging (MRI).

Methods

We studied 101 MRIs of patients with lumbar disease. The length from the upper and lower end plates of the vertebra to the lumbar arteries was measured. The measurement was conducted with coronal MRI images of every quarter slice of L1 to L4 vertebrae. We also investigated sagittal MRI images to determine whether the lumbar vessels are located on intervertebral disc in each level from L1/2 to L5/S1.

Results

The lumbar vessels are not always located at the center of the vertebrae. Some lumbar vessels are located within 8 mm from the end plates. Especially in L4, the lumbar vessels tended to go down from the anterior cranial side to the posterior caudal side (P < 0.01). 8, 24, and 54 lumbar vessels are located at the anterior quarter, the center, and the posterior quarter slice of the vertebrae, respectively, in L4. There were seven lumbar vessels in total located on the vertebral disc level.

Conclusions

It is necessary to investigate where the lumbar arteries are located to prevent its injury in LLIF, because the lumbar artery is not always located at the center of a vertebra. MRIs may provide a valuable information to avoid vascular injury during LLIF.

Anatomical Feasibility of Right Oblique Approach for L5-S1 Oblique Lumbar Interbody Fusion

BACKGROUND

We compared left and right vascular anatomy at the L5-S1 disc space and validated the anatomical feasibility of the right oblique approach for L5-S1 oblique lumbar interbody fusion.

METHODS

Axial T2-weighted magnetic resonance imaging studies at the L5-S1 disc level were used to study 274 subjects (164 women and 110 men; average age, 62.97 years). The distance from the center of the L5-S1 disc to the medial wall of the left or right vessel was measured. Using the vessel position, 3 groups were established: medial, middle, and lateral. To describe the morphological configuration, the vessel type and the presence of perivascular adipose tissue (PVAT) around the vessels were identified on both sides.

RESULTS

The vessels on the left L5-S1 disc space were located 12.47 mm from the midline and most subjects (209 subjects; 76.3%) were included in the medial or middle group. On the right side, the vessels were located more laterally (16.93 mm; P = 0.000) and most subjects (248 subjects; 90.5%) were in the middle or lateral group. On the left side, vessels were mostly veins (260 subjects; 94.9%) and 139 subjects (50.7%) had PVAT. On the right side, the vessels were mostly arteries (213 subjects; 77.7%) and 242 (88.3%) had PVAT.

CONCLUSIONS

The vessels on the right side of the L5-S1 disc were located more laterally, and most vessels on the right side were arteries accompanying PVAT, which might minimize vessel manipulation. These results indicate that the right side of the L5-S1 disc could provide feasible access for oblique lumbar interbody fusion at L5-S1.

Iatrogenic Bowel Injury Following Minimally Invasive Lateral Approach to the Lumbar Spine: A Retrospective Analysis of 3 Cases

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

Anterior approaches are often used during lumbar interbody fusion procedures. Visceral injuries (bowel injuries) are rare but represent a primary risk during anterior approaches to the lumbar spine. Left untreated, these injuries can result in significant complications. The aim of this study was to investigate the presentation and management of bowel injury cases following anterior approaches to the lumbar spine to raise the surgeon's awareness of this rare complication.

METHODS

All direct anterior, oblique anterior, and transpsoas lumbar interbody fusion surgeries performed at our institution between 2012 and 2016 were analyzed retrospectively. Charts were screened for cases requiring return to the operating room owing to a suspected bowel injury and details of the case were extracted for illustrative purposes.

RESULTS

A total of 775 anterior lumbar surgeries were conducted at a single tertiary care institution between July 2012 and June 2017. A total of 590 transpsoas lumbar interbody fusion (TPIF) surgeries were performed. Four patients, each having undergone TPIF, were suspected of bowel injury and underwent an exploratory laparotomy. At surgery, 3 patients were confirmed to have a bowel injury, giving a procedure-specific incidence of 0.51% and overall incidence of 0.39%. Among the 3 confirmed bowel injury cases, average delay between surgery and visceral injury diagnosis was 4.7 days (range 3-7 days).

CONCLUSIONS

We noted abdominal pain, distention, and fever as the most common findings in the setting of a visceral injury. A high index of suspicion and computed tomography imaging remain critical for identifying postoperative bowel injuries.

Sexual and urinary function following anterior lumbar surgery in females

AIMS

Anterior lumbar interbody fusion procedures (ALIF) and total disc replacement (TDR) with anterior exposure of the lumbar spine entail a risk of a vascular injury and dysfunction of the sympathetic and parasympathetic nerves due to disturbance of the inferior and superior hypogastric plexus. While retrograde ejaculation is a known complication of the anterior spinal approach in males, post-operative sexual as well as urinary function in females has not yet been thoroughly investigated and was hence the aim of this study.

METHODS

Fifteen female patients documented their sexual and urinary function preoperatively, 3 months and 6 months postoperatively, using the validated questionnaires FSFI (Female Sexual Function Index) and ICIQ (International Consultation of Incontinence Questionnaire). Randomization tests were used to statistically analyze expectation values over time (two-sided, P < 0.05).

RESULTS

While no statistically significant change in the total FSFI score occurred over time, a significant increase in FSFI desire score was noted between preoperative (2.95 ± 0.8) and 6 months follow-up (3.51 ± 0.6, P = 0.02). Urinary continence remained unchanged over time.

CONCLUSION

In summary, ALIF and lumbar TDR do not seem to negatively influence sexual and urinary function in females. In contrast, increased sexual desire was noted, likely secondary to post-surgical pain relief.

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.

Lumbar Intradiscal Invaginated Inferior Vena Cava Aneurysm

The objective of this study is to present a rare case of an invaginated inferior vena cava (IVC) aneurysm in the lumbar intradiscal space. A 73-year-old woman with lower back pain and bilateral lower extremity swelling presented to the clinic. She had undergone spinal surgery performed thrice at the same site (L4–L5) in another hospital and a separate posterolateral fusion surgery procedure 3 years previously. On plain radiography, pseudarthrosis was observed at L4–L5 segment. Contrast computed tomography (CT) imaging revealed a dilatation of the IVC in the intradiscal space of L4–L5. On the anterior side, anterior discectomy was performed. Following insertion of the allograft bone chip and cage, the invaginated IVC aneurysm was repositioned. Implant removal and screw fixation were performed posteriorly. Post-surgery, the patient’s lower back pain improved, and the start of anticoagulation treatment after vascular evaluation was planned. Although there have been numerous case reports of patients with intradiscal cysts or gas requiring surgical treatment, there have not yet been any reports of those with invaginated IVC in an intradiscal space. It is important to provide the appropriate treatment based on a thorough prior understanding of the patient’s anatomy.

Anterior Lumbar Fusion: Differences in Patient Selection and Surgical Outcomes Between Neurosurgeons and Orthopaedic Surgeons

OBJECTIVE

Anterior lumbar fusion (ALF) is performed by both neurosurgeons and orthopaedic surgeons. The aim of this study was to determine differences between the 2 surgical subspecialties in terms of patient selection and postoperative outcomes after ALF.

METHODS

A retrospective cohort study of adult patients undergoing ALF in the American College of Surgeons National Surgical Quality Improvement Program database from 2010 to 2014 was performed. Univariate analyses were performed to identify differences in baseline patient demographics, comorbidities, operative characteristics, and 30-day postoperative outcomes between neurosurgery and orthopaedic surgery patients. Multivariate logistic regression analysis was used to determine whether surgical subspecialty was an independent risk factor for postoperative complications.

RESULTS

The study included 3182 patients, with 1629 (51.2%) neurosurgery patients and 1553 (48.8%) orthopaedic surgery patients. A greater proportion of neurosurgery patients were >65 years old, were being treated with preoperative steroids, had cardiac or pulmonary comorbidities, and had an American Society of Anesthesiologists classification III or higher. ALF procedures performed by neurosurgeons more frequently involved use of intervertebral devices and bone graft. On multivariate logistic regression analysis, ALF procedures performed by neurosurgeons were independently associated with a higher risk of reoperation (odds ratio = 1.61; 95% confidence interval, 1.02-2.56; P = 0.042) and urinary tract infection (odds ratio = 1.94; 95% confidence interval, 1.02-3.68; P = 0.043).

CONCLUSIONS

In addition to differences in baseline patient demographics and comorbidities and operative characteristics, ALF performed by neurosurgeons had a higher risk of 30-day reoperation and urinary tract infection compared with ALF performed by orthopaedic surgeons.

Use of an Alternative Surgical Corridor in Oblique Lateral Interbody Fusion at the L5-S1 Segment: A Technical Report

STUDY DESIGN

Technical report.

OBJECTIVE

To demonstrate the use of an alternative surgical corridor in oblique lateral interbody fusion (OLIF) at the L5-S1 segment.

SUMMARY OF BACKGROUND DATA

OLIF L5-S1 is essentially performed through the central disk space between the bifurcations of the iliac vessels, which is sometimes difficult due to the vascular structures that obstruct the surgical field. Another concern is retrograde ejaculation following superior hypogastric plexus injury in male patients.

MATERIALS AND METHODS

The alternative surgical corridor involves the lateral disk space external to the left iliac vessels. The patient position and the retroperitoneal approach are similar to those used in the conventional OLIF L5-S1. The left iliac vessels are identified and mobilized medially to the midline of the L5-S1 disk space. The vascular structures are then protected using the conventional OLIF 51 retractor system.

RESULTS

Six patients underwent OLIF L5-S1 through the alternative lateral surgical corridor. The L5-S1 disk spaces were always exposed sufficiently for disk preparation and cage insertion. The postoperative radiographs showed a satisfactory L5-S1 reconstruction with good cage position. There were no perioperative complications during the surgical access and reconstruction procedures.

CONCLUSIONS

When the central approach to the L5-S1 disk space poses a risk of vascular or superior hypogastric plexus injury, use of a lateral approach external to the left iliac vessels can be an alternative method to perform OLIF L5-S1.

Clinical and Radiographic Results of a Minimally Invasive Lateral Transpsoas Approach for Treatment of Septic Spondylodiscitis of the Thoracolumbar and Lumbar Spine

BACKGROUND

The minimally invasive lateral transpsoas approach allows retroperitoneal access for discectomy and graft placement. However, the procedure has rarely been used for the treatment of septic spondylodiscitis. The purposes of this study were to evaluate the clinical and radiographic outcomes from this minimally invasive procedure for septic spondylodiscitis.

METHODS

Thirty-one consecutive patients (17 males and 14 females) were included in this study from July 2013 to January 2016. Clinical outcomes were assessed by Oswestry Disability Index, visual analog scale, modified Macnab criteria, and inflammatory parameters. Radiographic results were analyzed by studying the changes in diseased disc height, lordosis, and fusion status.

RESULTS

The Oswestry Disability Index and visual analog scale score improved by 58% and 69% at the last follow-up. The modified Macnab criteria were found to be excellent in 21 patients (68%) and good in 10 (32%). Inflammatory parameters normalized over the average 24 months follow-up. There were no major complications that might have influenced the outcomes in this cohort. A complete fusion after 12 months was achieved in 87% of patients. A mean 7.5 mm restoration in disc height and 6.4° restoration in lumbar lordosis were observed in all patients, whereas an average 4.5 mm loss in restored height resulting from graft subsidence was observed in 24 patients during the follow-up. However, graft subsidence did not influence clinical outcomes significantly.

CONCLUSIONS

A minimally invasive lateral transpsoas approach in combination with instrumentation provides a novel treatment for patients with septic spondylodiscitis without severe kyphosis and neurologic impairment.

Integrated anatomy of the neuromuscular, visceral, vascular, and urinary tissues determined by MRI for a surgical approach to lateral lumbar interbody fusion in the presence or absence of spinal deformity

Introduction

To comprehensively investigate the anatomy of the neuromuscular, visceral, vascular, and urinary tissues and their general influence on lateral lumbar interbody fusion (LLIF) surgery in the presence or absence of spinal deformity.

Methods

We retrospectively reviewed 100 consecutive surgery cases for lumbar degenerative disease of patients aged on average 70.5 years and of which 67 were women. A sagittal vertical axis deviation of more than 50 mm was defined as adult spinal deformity (ASD: 50 patients). The degenerative disease of the other patients was defined as lumbar spinal stenosis (LSS: 50 patients). We analyzed the relative anatomical position of the psoas major muscle, lumbar plexus, femoral nerves, inferior vena cava, abdominal aorta and its bifurcation, ureter, testicular or ovarian artery, kidney and transverse abdominal muscle in patients with ASD or with LSS, using preoperative magnetic resonance imaging (MRI).

Results

For patients with ASD, the L4-5 intervertebral disk was closer to the lumbar nerve plexus than it was in those with LSS (p < 0.0001), and a rising psoas sign at the L4-5 disk was significantly more frequent in patients with ASD than in those with LSS (p < 0.05). The aortic bifurcation frequently appeared at the level of L4-5 in patients with either degenerative disease, so the common iliac artery may pass near the disk. The inferior vena cava passed closer to the center of the L4-5 disk in patients with ASD than it did in those with LSS (p < 0.05). The transverse abdominal muscle at L2-3, L3-4, and L4-5 was closer to and less than 3 mm from the kidneys in many more patients with ASD than was the case for patients with LSS (p = 0.3, p < 0.05, p = 0.29, respectively).

Conclusions

We recommend careful preoperative MRI to determine the location of organs to help to avoid intraoperative complications during LLIF surgery, especially for patients with ASD.

Nerve Root and Lumbar Plexus Proximity to Different Extraforaminal Lumbar Interbody Fusion Trajectories: A Cadaver Study

STUDY DESIGN

Cadaver study.

OBJECTIVE

To investigate the safety of the extraforaminal lumbar interbody fusion approach.

SUMMARY OF BACKGROUND DATA

Over the last decade the number of techniques available for lumbar interbody fusion has increased. Recent interest has developed in an extraforaminal approach to the intervertebral disc to reduce the morbidity associated with facetectomy. The safety of this extraforaminal corridor with regards to the exiting nerve root and lumbar plexus has yet to be assessed.

METHODS

With the cadaver prone, the C-arm was positioned over the disc of interest and aligned perpendicular to the superior endplate of the inferior vertebral body, with the superior articular process bisecting the available disc space. Three needles were passed into the disc and labeled medial, middle, and lateral. After needle placement, each nerve root and the lumbar plexus were dissected. The distance of each needle to these structures was measured and discectomy was performed to assess potential graft length from a transforaminal and extraforaminal approach.

RESULTS

We performed the method on levels L1-L5 bilaterally on 2 cadavers, totaling 16 attempts for each needle position. The average distance to nerve of the medial approach (3.2±1.1 mm) was statistically greater than both the middle (1.1±1.4 mm) and lateral (-0.2±2.9 mm) approaches (P<0.0001 for both). The distance to plexus of the medial approach (14.3±6.2 mm) was greater than the middle (9.2±6.1 mm) approach and statistically greater than the lateral (5.2±5.6 mm) approach (P=0.001). There was a greater graft length available by the extraforaminal lumbar interbody fusion approach (36.1±2.7 mm) than the transforaminal lumbar interbody fusion approach (29.3±3.5 mm, P<0.0001).

CONCLUSIONS

The safest trajectory was the medial, passing adjacent to the superior articular process. The close proximity, however, means that neuromonitoring and tubular dilators would be necessary to use this technique in a clinical setting.

LEVEL

Level V.

Interbody Fusion Techniques in the Surgical Management of Degenerative Lumbar Spondylolisthesis

PURPOSE OF REVIEW

The various lumbar interbody fusion (IBF) techniques and the evidence for their use in the treatment of degenerative lumbar spondylolisthesis (DLS) are described in this review.

RECENT FINDINGS

The existing evidence is mixed regarding the indications for and utility of IBF in DLS, but its use in the setting of pre-operative instability is most strongly supported. Anterior (ALIF), lateral (LLIF), posterior (PLIF), transforaminal (TLIF), and axial (AxiaLIF) lumbar IBF approaches have been described. While the current data are limited, TLIF may be a better option than PLIF in DLS due the increased operative morbidity and peri-operative complications observed with the latter. LLIF also appears superior to PLIF in light of improved radiologic outcomes, fewer intra-operative complications, and potentially greater improvements in disability. The data comparing LLIF to TLIF are less conclusive. No studies specifically comparing ALIF or AxiaLIF to other IBF techniques could be identified. Instability may be the strongest indication for IBF in DLS. When IBF is employed, the authors' preferred technique is TLIF with posterior segmental spinal instrumentation. Further research is needed.

High-Risk Subgroup Membership Is a Predictor of 30-Day Morbidity Following Anterior Lumbar Fusion

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To determine if membership in a high-risk subgroup is predictive of morbidity and mortality following anterior lumbar fusion (ALF).

METHODS

The American College of Surgeons National Surgical Quality Improvement Program database was utilized to identify patients undergoing ALF between 2010 and 2014. Multivariate analysis was utilized to identify high-risk subgroup membership as an independent predictor of postoperative complications.

RESULTS

Members of the elderly (≥65 years) (OR = 1.3, P = .02) and non-Caucasian (black, Hispanic, other) (OR = 1.7, P < .0001) subgroups were at greater risk for a LOS ≥5 days. Obese patients (≥30 kg/m² ) were at greater risk for an operative time ≥4 hours (OR = 1.3, P = .005), and wound complications (OR = 1.8, P = .024) compared with nonobese patients. Emergent procedures had a significantly increased risk for LOS ≥5 days (OR = 4.9, P = .021), sepsis (OR = 14.8, P = .018), and reoperation (OR = 13.4, P < .0001) compared with nonemergent procedures. Disseminated cancer was an independent risk factor for operative time ≥4 hours (OR = 8.4, P < .0001), LOS ≥5 days (OR = 15.2, P < .0001), pulmonary complications (OR = 7.4, P = .019), and postoperative blood transfusion (OR = 3.1, P = .040).

CONCLUSIONS

High-risk subgroup membership is an independent risk factor for morbidity following ALF. These groups should be targets for aggressive preoperative optimization, and quality improvement initiatives.