Incidence of vascular complications during lateral lumbar interbody fusion: an examination of the mini-open access technique

Advances and Challenges in Minimally Invasive Spine Surgery

Minimally invasive spine surgery continues to grow and develop. Over the past 50 years, there has been immense growth within this subspecialty of neurosurgery. A deep understanding of the historical context and future directions of this subspecialty is imperative to developing safe adoption and targeted innovation. This review aims to describe the advancements, and challenges that we face today in minimally invasive spine surgery.

Establishing a Standardized Clinical Consensus for Reporting Complications Following Lateral Lumbar Interbody Fusion

Background and Objectives: Mitigating post-operative complications is a key metric of success following interbody fusion. LLIF is associated with a unique complication profile when compared to other approaches, and while numerous studies have attempted to report the incidence of post-operative complications, there is currently no consensus regarding their definitions or reporting structure. The aim of this study was to standardize the classification of complications specific to lateral lumbar interbody fusion (LLIF). Materials and Methods: A search algorithm was employed to identify all the articles that described complications following LLIF. A modified Delphi technique was then used to perform three rounds of consensus among twenty-six anonymized experts across seven countries. Published complications were classified as major, minor, or non-complications using a 60% agreement threshold for consensus. Results: A total of 23 articles were extracted, describing 52 individual complications associated with LLIF. In Round 1, forty-one of the fifty-two events were identified as a complication, while seven were considered to be approach-related occurrences. In Round 2, 36 of the 41 events with complication consensus were classified as major or minor. In Round 3, forty-nine of the fifty-two events were ultimately classified into major or minor complications with consensus, while three events remained without agreement. Vascular injuries, long-term neurologic deficits, and return to the operating room for various etiologies were identified as important consensus complications following LLIF. Non-union did not reach significance and was not classified as a complication. Conclusions: These data provide the first, systematic classification scheme of complications following LLIF. These findings may improve the consistency in the future reporting and analysis of surgical outcomes following LLIF.

[Transmuscular approach (XLIF technique) for anterior surgery of the lumbar spine]

OBJECTIVE

Anterior stabilization of the spine with a lateral approach to insert a large and broad cage creating a better bearing surface to restore or maintain the lumbar lordosis.

INDICATIONS

Degenerative scoliosis as well as revision surgery for stenosis of the neuroforamen. Lumbar corpectomies between L2/3 and L4/5 can be approached as well.

CONTRAINDICATIONS

The segment L5/S1 is not suitable for the transmuscular approach. Relative contraindications are previous retroperitoneal surgery and spondylolisthesis with sliding of more than 50% (> Meyerding 2) SURGICAL TECHNIQUE: We describe the transmuscular retroperitoneal approach to the lumbar segments which is called extreme lateral approach (XLIF). To protect the spinal nerves on the way through the psoas muscle, use of intraoperative triggered neuromonitoring is paramount.

POSTOPERATIVE MANAGEMENT

Full mobilization directly after surgery is possible in most cases. Weight bearing should be restricted to 20 kg for 3 months after surgery.

RESULTS

The transmuscular approach to the lumbar spine is a good alternative to reach the anterior part of the lumbar spine. Degenerative scoliosis as well as stenosis of the neuroforamen especially in revision surgery are good indications for this technique. Injuries of the spinal nerves range from 0.7 to 15%. Other complications are rare.

Incidence of major and minor vascular injuries during lateral access lumbar interbody fusion procedures: a retrospective comparative study and systematic literature review

During lateral lumbar fusion, the trajectory of implant insertion approaches the great vessels anteriorly and the segmental arteries posteriorly, which carries the risk of vascular complications. We aimed to analyze vascular injuries for potential differences between oblique lateral interbody fusion (OLIF) and lateral lumbar interbody fusion (LLIF) procedures at our institution. This was coupled with a systematic literature review of vascular complications associated with lateral lumbar fusions. A retrospective chart review was completed to identify consecutive patients who underwent lateral access fusions. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were used for the systematic review with the search terms "vascular injury" and "lateral lumbar surgery." Of 260 procedures performed at our institution, 211 (81.2%) patients underwent an LLIF and 49 (18.8%) underwent an OLIF. There were no major vascular complications in either group in this comparative study, but there were four (1.5%) minor vascular injuries (2 LLIF, 0.95%; 2 OLIF, 4.1%). Patients who experienced vascular injury experienced a greater amount of blood loss than those who did not (227.5 ± 147.28 vs. 59.32 ± 68.30 ml) (p = 0.11). In our systematic review of 63 articles, major vascular injury occurred in 0-15.4% and minor vascular injury occurred in 0-6% of lateral lumbar fusions. The systematic review and comparative study demonstrate an increased rate of vascular injury in OLIF when compared to LLIF. However, vascular injuries in either procedure are rare, and this study aids previous literature to support the safety of both approaches.

Rating the incidence of iatrogenic vascular injuries in thoracic and lumbar spine surgery as regards the approach: A PRISMA-based literature review

PURPOSE

To assess the rate, timing of diagnosis, and repairing strategies of vascular injuries in thoracic and lumbar spine surgery as their relationship to the approach.

METHODS

PubMed, Medline, and Embase databases were utilized for a comprehensive literature search based on keywords and mesh terms to find articles reporting iatrogenic vascular injury during thoracic and lumbar spine surgery. English articles published in the last ten years were selected. The search was refined based on best match and relevance.

RESULTS

Fifty-six articles were eligible, for a cumulative volume of 261 lesions. Vascular injuries occurred in 82% of instrumented procedures and in 59% during anterior approaches. The common iliac vein (CIV) was the most involved vessel, injured in 49% of anterior lumbar approaches. Common iliac artery, CIV, and aorta were affected in 40%, 28%, and 28% of posterior approaches, respectively. Segmental arteries were injured in 68% of lateral approaches. Direct vessel laceration occurred in 81% of cases and recognized intraoperatively in 39% of cases.

CONCLUSIONS

Incidence of iatrogenic vascular injuries during thoracic and lumbar spine surgery is low but associated with an overall mortality rate up to 65%, of which less than 1% for anterior approaches and more than 50% for posterior ones. Anterior approaches for instrumented procedures are at risk of direct avulsion of CIV. Posterior instrumented fusions are at risk for injuries of iliac vessels and aorta. Lateral routes are frequently associated with lesions of segmental vessels. Suture repair and endovascular techniques are useful in the management of these severe complications.

Segmental Arteries and Veins at Higher Lumbar Levels Can Intersect the Adjacent Caudal Intervertebral Disc in the Anterior Part of the Spinal Column: A Cadaveric Analysis

Study Design

A cadaveric study.

Purpose

To investigate the anatomical features of segmental arteries and veins in the anterior part of the spinal column to prevent segmental vessel injury.

Overview of Literature

The lateral transpsoas approach to the lumbar intervertebral discs (IVD) is associated with the risk of segmental vessel injury. Previous studies have described the vascular anatomy on the lateral part of the vertebral body. However, there are no studies that describe the segmental vessels on its anterior aspect. Here, we report the important anatomical features of the segmental arteries and veins that can intersect the anterior part of the IVD. These vessels are considered at risk of vascular injury when placing the anterior retractors during lateral lumbar interbody fusion or cutting the anterior longitudinal ligament during anterior column realignment.

Methods

Five formalin-embalmed human cadavers were used. We assessed the proportion of segmental arteries and veins that intersected the IVD in the L2–L5 range and their course on the anterior part of the spinal column.

Results

The segmental arteries and veins commonly intersect the anterior part of the IVD (artery, 28.1%; vein, 42.1%). Seven of 10 (70%) segmental arteries at L2 intersected the IVD, but only one artery intersected the IVD at L3 and L4. The proportions of segmental veins that intersected the IVD were 60%, 50%, and 16.7% at L2, L3, and L4, respectively.

Conclusions

The segmental arteries and veins frequently intersect the IVD in the anterior part of the spinal column. Therefore, it is necessary to consider these individual anatomical features to prevent vascular damage during lateral lumbar interbody fusion surgery.

Simultaneous Combined Major Arterial and Lumbar Plexus Injury During Primary Extra Lateral Interbody Fusion: Case Report and Review of the Literature

Extra lateral interbody fusion (XLIF) has been established in recent years as an effective approach to address degenerative lumbar disc disease (DLDD). Although neurological and vascular complications during XLIF have been reported, to our knowledge, a combination of simultaneous vascular and neurovascular complication during XLIF has not been reported to date. A 72-year-old female patient was admitted to our orthopaedic department because of back pain associated with severe neuropathic radicular pain to her both lower extremities, incomplete paraplegia and low back fistula with serous secretion for several weeks. She had been wheel-chair bound since nine years before her admission in our department when she had her initial XLIF operation in another institution. Intraoperatively, an aorta lesion occurred, which was emergently addressed, along with lumbar plexus injury. Since then, she had an extensive history of subsequent operations that ended with a T10-S1 posterior lumbar fusion, with no improvement of her neurological condition, complicated by hardware-induced infection. She underwent her last operation in our department; removal of the posterior lumbar construct and extensive debridement of the posterior lumbar spine. We present this rare case and we perform an extensive literature review. Although XLIF has been established in recent years, the report of major vascular injuries, although rare, has questioned its safety profile. Spine surgeons should be aware of catastrophic major neurovascular complications associated with this procedure and be prepared to address them.

Lateral Lumbar Interbody Fusion: Review of Surgical Technique and Postoperative Multimodality Imaging Findings

The lateral lumbar interbody fusion (LLIF) approach is a minimally invasive surgery that can be used as an alternative to traditional lumbar interbody fusion techniques. LLIF accesses the intervertebral disk through the retroperitoneum and psoas muscle to avoid major vessels and visceral organs. The exposure of retroperitoneal structures during LLIF leads to unique complications compared with other surgical approaches. An understanding of the surgical technique and its associated potential complications is necessary for radiologists who interpret imaging before and after LLIF. Preoperative imaging must carefully assess the location of anatomic structures, including major retroperitoneal vasculature, lumbar nerve roots, lumbosacral plexus, and the genitofemoral nerve, relative to the psoas muscle. Multiple imaging modalities can be used in postoperative assessment including radiographs, CT, CT myelography, and MRI. Of these, CT is the preferred modality, because it can assess a range of complications relating to both the retroperitoneal exposure and the spinal instrumentation, as well as bone integrity and fusion status. This article describes surgical approaches for lumbar interbody fusion, comparing the approaches' indications, contraindications, advantages, and disadvantages; reviews the surgical technique of LLIF and relevant anatomic considerations; and illustrates for interpreting radiologists the normal postoperative findings and potential postsurgical complications of LLIF.

The impact of age on approach-related complications with navigated lateral lumbar interbody fusion

OBJECTIVE

Age is known to be a risk factor for increased complications due to surgery. However, elderly patients can gain significant quality-of-life benefits from surgery. Lateral lumbar interbody fusion (LLIF) is a minimally invasive procedure that is commonly used to treat degenerative spine disease. Recently, 3D navigation has been applied to LLIF. The purpose of this study was to determine whether there is an increased complication risk in the elderly with navigated LLIF.

METHODS

Patients who underwent 3D-navigated LLIF for degenerative disease from 2014 to 2019 were included in the analysis. Patients were divided into elderly and nonelderly groups, with those 65 years and older categorized as elderly. Ninety-day medical and surgical complications were recorded. Patient and surgical characteristics were compared between groups, and multivariate regression analysis was used to determine independent risk factors for complication.

RESULTS

Of the 115 patients included, 56 were elderly and 59 were nonelderly. There were 15 complications (25.4%) in the nonelderly group and 10 (17.9%) in the elderly group, which was not significantly different (p = 0.44). On multivariable analysis, age was not a risk factor for complication (p = 0.52). However, multiple-level LLIF was associated with an increased risk of approach-related complication (OR 3.58, p = 0.02).

CONCLUSIONS

Elderly patients do not appear to experience higher rates of approach-related complications compared with nonelderly patients undergoing 3D navigated LLIF. Rather, multilevel surgery is a predictor for approach-related complication.

Major complications in extreme lateral interbody fusion access: multicentric study by Italian S.O.L.A.S. group

PURPOSE

The eXtreme Lateral Interbody Fusion (XLIF) approach has gained increasing importance in the last decade. This multicentric retrospective cohort study aims to assess the incidence of major complications in XLIF procedures performed by experienced surgeons and any relationship between the years of experience in XLIF procedures and the surgeon's rate of severe complications.

METHODS

Nine Italian members of the Society of Lateral Access Surgery (SOLAS) have taken part in this study. Each surgeon has declared how many major complications have been observed during his surgical experience and how they were managed. A major complication was defined as an injury that required reoperation, or as a complication, whose sequelae caused functional limitations to the patient after one year postoperatively. Each surgeon was finally asked about his years of experience in spine surgery and XLIF approach. Pearson correlation test was used to evaluate the association between the surgeon's years of experience in XLIF and the rate of major complications; a p-value of last than 0.05 was considered significant.

RESULTS

We observed 14 major complications in 1813 XLIF procedures, performed in 1526 patients. The major complications rate was 0.7722%. Ten complications out of fourteen needed a second surgery. Neither cardiac nor respiratory nor renal complications were observed. No significant correlation was found between the surgeon's years of experience in the XLIF procedure and the number of major complications observed.

CONCLUSION

XLIF revealed a safe and reliable surgical procedure, with a very low rate of major complications, when performed by an expert spine surgeon.

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.

The effect of vascular approach surgeons on perioperative complications in lateral transpsoas lumbar interbody fusions

BACKGROUND CONTEXT

Lateral lumbar interbody fusion (LLIF) is a popular technique used in spine surgery. It is minimally invasive, provides indirect decompression, and allows for coronal plane deformity correction. Despite these benefits, the approach to LLIF has been linked to complications associated with the lumbosacral plexus and vascular anatomy. As a result, vascular surgeons may be recruited for the exposure portion of the procedure.

PURPOSE

The purpose of this study was to compare exposure-related complication and postoperative (postop) neuropraxia rates between exposure (EXP) and spine surgeon only (SSO) groups while performing the approach for LLIF.

STUDY DESIGN/SETTING

Retrospective analysis of patients treated at a single institution.

PATIENT SAMPLE

Patients undergoing LLIF procedures between 2012 and 2018.

OUTCOME MEASURES

Operative time, estimated blood loss, fluoroscopy, length of stay (LOS), intra- and postoperative complications, and physiologic measures including pre- and postoperative motor examinations and unresolved neuropraxia.

METHODS

Patients who underwent LLIF were separated into EXP and SSO groups based on the presence or absence of vascular/general surgeon during the approach. The entire clinical history of patients with a decrease in pre- and postop motor examination was reviewed for the presence of neuropraxia. All other intra- and postop exposure-related complications were recorded for comparison. Propensity score matching (PSM) was performed to account for age, Charlson Comorbidity Index (CCI) percentage of LLIFs including L4-L5, and number of levels fused. Independent t test and chi-square analyses were used to identify significant differences between EXP and SSO groups. Statistical significance was set at p<.05.

RESULTS

Two hundred and seventy-five patients underwent LLIF procedures, 155 SSO and 120 EXP. Postoperatively, 26 patients (11.1%) experienced a drop in any Medical Research Council (MRC) score, and two patients (0.7%) experienced unresolved quadriceps palsies. The mean recovery time for MRC scores was 84.4 days. Other complications included 2 pneumothoraces (0.7%), 1 iliac vein injury (0.4%), 14 cases of ileus (5.1%), 3 pulmonary emboli (1.1%), 2 deep vein thrombosis (0.7%), 3 cases of abdominal wall paresis (1.1%), and one abdominal hematoma (0.4%). After PSM, demographics including age, gender, body mass index, CCI, levels fused, and operative time were similar between cohorts. Twenty patients had changes in pre- to postop motor scores (SSO 9.4%, EXP 12.4%, p>.05). Iliopsoas motor scores decreased at the highest rate (EXP 12.4%, SSO 8.2%, p>.05) followed by quadriceps (EXP 5.2%, SSO 4.7%, p>.05). One SSO patient's postop course was complicated by a foot drop but returned to baseline within 1 year. One patient in EXP group developed an unresolved quadriceps palsy (EXP 1.0%, SSO 0.0%, p>.05). Intraoperative exposure complications included one pneumothorax (EXP 1.0%, SSO 0.0%, p>.05). There were no differences in PE/DVT, Ileus, or LOS. In the EXP cohort, three patients experienced abdominal wall paresis (EXP 2.9%, SSO 0.00%, p=.246).

CONCLUSIONS

Comparing the LLIF exposures performed by EXP and SSO, we found no significant difference in the rates of complications. Additional research is needed to determine the etiology of the abdominal wall complications. In conclusion, neuropraxia- and approach-related complications are similarly low between exposure and spine surgeons.

One-stage Debridement via Oblique Lateral Interbody Fusion Corridor Combined with Posterior Pedicle Screw Fixation in Treating Spontaneous Lumbar Infectious Spondylodiscitis: A Case Series

Objective

Surgery is indicated when antibiotic treatment fails in pyogenic spondylodiscitis, which is caused by pathogens such as the Staphylococcus species. The aim of the present study was to investigate the efficacy and safety of the oblique lateral interbody fusion (OLIF) corridor approach combined with posterior pedicle screw fixation for treating pyogenic spondylodiscitis.

Methods

This was a retrospective case series study. A total of 11 patients with an average age of 60.7 years (range, 40–70 years; 10 males and 1 females) with lumbar pyogenic spondylodiscitis who underwent single‐stage debridement and reconstruction using the OLIF corridor combined with posterior pedicle screw fixation were recruited in our study from June 2016 to July 2017. All patients had single‐level pyogenic spondylodiscitis between T₁₂ and L₅. The baseline data, perioperative outcomes (operative time, intra‐operative blood loss, and intra‐operative complication), postoperative laboratory tests (erythrocyte sedimentation rate [ESR], C‐reactive protein [CRP], white blood count [WBC], and tissue culture results), long‐term complications (recurrence, fixation failure, and bony non‐fusion rates), and duration of antibiotic administration were reviewed. Outcomes evaluated using a variety of scales including visual analog scale (VAS) score and Oswestry disability index (ODI), were compared pre‐operatively and post‐operatively.

Results

The mean follow‐up period of time was 18.3 months. The average operative time and intra‐operative blood loss were 217.0 ± 91.91 min and 220.9 ± 166.10 mL, respectively. There were no intra‐operative complications, except in 1 patient who encountered somatosensory evoked potentials changes and 1 patient who had motor evoked potentials changes, both without post‐surgery neurological deficits. Causative organisms were identified in 4 patients: Staphylococcus aureus in 1 patient and Streptococcus in 3 patients. At approximately 8.8 weeks after surgery, WBC, CRP, and ESR had returned to normal levels. All patients were pain free with no recurring infection. There was no fixation failure during follow up. Solid bony fusions were observed in all cases within 6 months. At the final follow up, the mean VAS (0.6 ± 0.69) and ODI (14.4 ± 4.27) were significantly lower than those before surgery (P < 0.05).

Conclusion

One‐stage debridement with autogenous iliac bone graft through the OLIF corridor combined with posterior pedicle screw fixation is effective and safe for single‐level spontaneous lumbar pyogenic spondylodiscitis after antibiotic treatment fails.

Mini-Open Access for Lateral Lumbar Interbody Fusion: Indications, Technique, and Outcomes

Background

Lateral lumbar interbody fusion (LLIF) is a relatively new procedure. It was established as a minimally invasive alternative to traditional open interbody fusion. LLIF allows the surgeon to access the disc space via a retroperitoneal transpsoas muscle approach. Theoretical advantages of the LLIF technique include preservation of the longitudinal ligaments, augmentation of disc height with indirect decompression of neural elements, and insertion of large footprint cages spanning the dense apophyseal ring bilaterally^1,2. The original 2-incision LLIF technique described by Ozgur et al., in 2006, had some inherent limitations³. First, it substantially limited direct visualization of the surgical field and may have endangered nerve and vascular structures. Additionally, it often required multiple separated incisions for multilevel pathologies. Finally, for surgeons with experience in traditional open retroperitoneal surgery, utilization of their previously acquired skills may have been difficult with this approach. To overcome these limitations, we adopted the mini-open lateral approach, which allows for visualization, palpation, and electrophysiologic neurologic confirmation during the procedure⁴.

Description

As detailed below, the patient is positioned in the lateral decubitus position and a single incision is carried out centered between the target discs. For single-level LLIF, the incision spans approximately 3 cm and can be lengthened in small increments for multilevel procedures. After blunt dissection, the retroperitoneal space is entered. The psoas muscle is split under direct visualization, carefully avoiding the traversing nerves with neurosurveillance⁵. A self-retaining retractor is used, and after thorough discectomy, the disc space is sized with trial components. The implant is filled with bone graft materials and is introduced using intraoperative fluoroscopy.

Alternatives

The 2-incision LLIF technique or traditional anterior or posterior lumbar spine interbody fusion techniques might be used instead.

Rationale

LLIF offers the reported advantages of minimally invasive surgery, such as reduced tissue trauma during the approach, low blood loss, shorter length of stay, decreased recovery time, and less postoperative pain. LLIF allows for the placement of a relatively larger interbody cage spanning the dense apophyseal ring bilaterally. The lateral approach preserves the anterior longitudinal ligament and posterior longitudinal ligament. These structures allow for powerful ligamentotaxis and provide extra stability for the construct. Compared with other approaches, LLIF has a reduced risk of visceral and vascular injuries, incidental dural tears, and perioperative infections. Although associated with approach-related complications such as motor and sensory deficits, LLIF can be a safe and versatile procedure^1,2.

Complications Associated With Minimally Invasive Anterior to the Psoas (ATP) Fusion of the Lumbosacral Spine

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

To analyze complications associated with minimally invasive anterolateral retroperitoneal antepsoas lumbosacral fusion (MIS-ATP).

SUMMARY OF BACKGROUND DATA

MIS-ATP provides anterolateral access to the lumbar spine allowing for safe anterior lumbar interbody fusions between T12-S1. Anecdotally, many surgeons believe that ATP approach is not feasible at L5-S1 level, predisposing to catastrophic vascular injuries. This approach may help overcome limitations associated with conventional straight anterior lumbar interbody fusions, MIS lateral lumbar interbody fusion, and oblique lateral interbody fusion.

METHODS

A detailed retrospective chart review of patients who had underwent MIS-ATP approach for lumbar fusion between T12-S1 was performed. Available electronic data from surgeries performed between January 2008 and March 2017 was carefully screened for surgical patients treated for spondylolisthesis, spondylosis, stenosis, sagittal, and/or coronal deformity. Detailed review of electronic medical records including operative notes, progress notes, discharge summaries, laboratory results, imaging reports, and clinic visit notes performed by a single independent reviewer not involved in patient care for documented complications. A complication is defined as any adverse event related to the index spine procedure for which patient required specific intervention or treatment.

RESULTS

Nine hundred forty patients with a total of 2429 interbody fusion levels performed via MIS-ATP were identified during the study period. Sixty-seven patients (7.2%) sustained one or more complications during the perioperative period, of which 25.5% were surgical and 74.5% were medical. Overall, 78 (8.2%) surgical complications pertaining to the index procedure were noted during a postoperative period of 1 year from the date of surgery. No major vascular or direct visceral injuries were encountered.

CONCLUSIONS

MIS-ATP approach provides a safe access to anterolateral interbody fusions between T12-S1. The ATP approach is performed by the spine surgeon, does not require neuromonitoring, and warrants minimal to no psoas muscle retraction resulting in significantly reduced postoperative thigh pain and rare neurologic injuries. Additionally, the direct and clear visualization of the retroperitoneal vasculature provided by the ATP approach minimizes the risk of inadvertent vascular injury.

LEVEL OF EVIDENCE

4.

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.

Perioperative complications associated with minimally invasive surgery of oblique lumbar interbody fusions for degenerative lumbar diseases in 113 patients

OBJECTIVES

To describe perioperative complications occurring during oblique lumbar interbody fusion (OLIF) assisted by a retractor system for degenerative lumbar diseases.

PATIENTS AND METHODS

The perioperative complications in 113 cases series utilizing a minimally invasive approach were recorded and analyzed. One hundred thirteen patients who received OLIF for degenerative lumbar diseases between November 2014 and February 2017 at a single center were evaluated. The most frequent diagnosis was spondylolisthesis (59 cases, 52.2%), followed by lumbar instability (24 cases, 21.2%), adjacent segmental disease (12 cases, 10.6%), adult degenerative scoliosis (11 cases, 9.8%) and discogenic low back pain (7 cases, 6.2%). One hundred thirty-four levels were treated, 88.5% one-level, 4.4% two-level, and 7.1% three-level surgeries. The most fused level was L4-5 (94 levels, 70.2%), followed by L3-4 (31 levels, 23.1%), and L2-3 (9 levels, 6.7%).

RESULTS

All perioperative complications only included adverse events related to the OLIF procedure. The most observed complications were donor-site pain (24 cases, 21.2%), followed by vertebral endplate fracture (15 cases, 13.3%), thigh numbness/pain (12 cases, 10.6%), psoas/quadriceps weakness (5 cases, 4.4%), sympathetic nerve injury (2 case, 1.8%), paralytic ileus (one case, 0.9%), segmental artery injury (one case, 0.9%), intervertebral infection (one, 0.9%), and contralateral femoral nerve palsy (one, 0.9%). All complications, including postoperative ipsilateral or contralateral thigh paresthesia, pain, and psoas/quadriceps weakness, were observed when operating at L4-L5. The incidence of complications excluding donor-site pain was 24.8% (28/113 cases). The patients with donor-site pain, thigh numbness/pain, psoas/quadriceps weakness, sympathetic nerve injury and paralytic ileus recovered within two months following surgery. The patient with intervertebral infection recovered at 3 months after surgery. One case of contralateral femoral nerve palsy recovered completely with no residual sensory or motor deficit at 6 months.

CONCLUSIONS

OLIF performed using a retractor system is a validated option to treat a wide spectrum of degenerative lumbar diseases with few perioperative complications and a quick recovery. Judicious use of this technique at the L4/5 level is recommended. Close attention to detail during the procedure can minimize complications that may be associated with the learning curve.

Intercostal artery hemorrhage with hemothorax following combined lateral and posterior lumbar interbody fusion: a case report

Introduction

Lateral lumbar interbody fusion (LLIF) is a safe treatment for degenerative spine conditions. However, risk of complications such as vascular injuries remains. We report a unique case of an intercostal artery (ICA) hemorrhage with hemothorax following LLIF.

Case presentation

One hour after a right-sided LLIF L3-4 with posterior decompression L2-4 and L3-5 instrumentation, the patient became hypotensive, anemic and required vasopressor support. Evaluation revealed a right-sided hemothorax, which was caused by a bleeding intercostal artery, laterally at the 10th intercostal space. A lateral thoracotomy was performed to stop the bleeding. After vessel ligation and placement of two chest tubes, the patients' hemodynamics improved. The patient remained intubated overnight and was extubated on the first postoperative day.

Discussion

Vascular injury is a rare complication of LLIF procedures. Most vascular injuries are segmental vessel lacerations, which resolve postoperatively. This is the first case description of ICA bleeding associated with LLIF surgery. Spontaneous ICA bleeding exists, but surgeons should be aware of careful handling in patients with vascular risk factors, especially with regard to patient positioning required in certain spinal surgical approaches. Timely vascular injury identification is critical for hemostasis and clinical management.

Complications for minimally invasive lateral interbody arthrodesis: a systematic review and meta-analysis comparing prepsoas and transpsoas approaches

OBJECTIVE

Minimally invasive anterolateral retroperitoneal approaches for lumbar interbody arthrodesis have distinct advantages attractive to spine surgeons. Prepsoas or transpsoas trajectories can be employed with differing complication profiles because of the inherent anatomical differences encountered in each approach. The evidence comparing them remains limited because of poor quality data. Here, the authors sought to systematically review the available literature and perform a meta-analysis comparing the two techniques.

METHODS

A systematic review and meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A database search was used to identify eligible studies. Prepsoas and transpsoas studies were compiled, and each study was assessed for inclusion criteria. Complication rates were recorded and compared between approach groups. Studies incorporating an analysis of postoperative subsidence and pseudarthrosis rates were also assessed and compared.

RESULTS

For the prepsoas studies, 20 studies for the complications analysis and 8 studies for the pseudarthrosis outcomes analysis were included. For the transpsoas studies, 39 studies for the complications analysis and 19 studies for the pseudarthrosis outcomes analysis were included. For the complications analysis, 1874 patients treated via the prepsoas approach and 4607 treated with the transpsoas approach were included. In the transpsoas group, there was a higher rate of transient sensory symptoms (21.7% vs 8.7%, p = 0.002), transient hip flexor weakness (19.7% vs 5.7%, p < 0.001), and permanent neurological weakness (2.8% vs 1.0%, p = 0.005). A higher rate of sympathetic nerve injury was seen in the prepsoas group (5.4% vs 0.0%, p = 0.03). Of the nonneurological complications, major vascular injury was significantly higher in the prepsoas approach (1.8% vs 0.4%, p = 0.01). There was no difference in urological or peritoneal/bowel injury, postoperative ileus, or hematomas (all p > 0.05). A higher infection rate was noted for the transpsoas group (3.1% vs 1.1%, p = 0.01). With regard to postoperative fusion outcomes, similar rates of subsidence (12.2% prepsoas vs 13.8% transpsoas, p = 0.78) and pseudarthrosis (9.9% vs 7.5%, respectively, p = 0.57) were seen between the groups at the last follow-up.

CONCLUSIONS

Complication rates vary for the prepsoas and transpsoas approaches owing to the variable retroperitoneal anatomy encountered during surgical dissection. While the risks of a lasting motor deficit and transient sensory disturbances are higher for the transpsoas approach, there is a reciprocal reduction in the risks of major vascular injury and sympathetic nerve injury. These results can facilitate informed decision-making and tailored surgical planning regarding the choice of minimally invasive anterolateral access to the spine.

Minimally invasive anterior, lateral, and oblique lumbar interbody fusion: a literature review

Lumbar interbody fusion involves insertion of a structural graft into an intervertebral disc space to promote bony arthrodesis. It is a well-established surgical strategy for multiple spinal disorders ranging from degenerative conditions to trauma, neoplastic diseases, and deformities requiring correction. Since the inception of lumbar interbody fusion, the most established techniques have been two posterior approaches, the posterior lumbar interbody fusion (PLIF) and the transforaminal lumbar interbody fusion (TLIF). Within the past 15 years, multiple anterolateral approaches to the spine have become widely adopted. These approaches can be performed minimally invasively and spare disruption of the paraspinal muscles and posterior spinal column while enabling wide exposure of the disc space for insertion of interbody grafts much larger than PLIF and TLIF instrumentation. This review highlights three minimally invasive anterolateral approaches: the anterior lumbar interbody fusion (ALIF), the transpsoas lateral lumbar interbody fusion (LLIF), and prepsoas or anterior to the psoas oblique lumbar interbody fusion (OLIF). Relevant topics for discussion and comparison include patient selection, surgical techniques, outcomes, and complications for the three surgical approaches.

Lateral Lumbar Interbody Fusion-Outcomes and Complications

PURPOSE OF REVIEW

Lateral lumbar interbody fusion (LLIF) is a relatively new, minimally invasive technique for interbody fusion. The goal of this review is to provide a general overview of LLIF with a special focus on outcomes and complications.

RECENT FINDINGS

Since the first description of the technique in 2006, the indications for LLIF have expanded and the rate of LLIF procedures performed in the USA has increased. LLIF has several theoretical advantages compared to other approaches including the preservation of the anterior and posterior annular/ligamentous structures, insertion of wide cages resting on the dense apophyseal ring bilaterally, and augmentation of disc height with indirect decompression of neural elements. Favorable long-term outcomes and a reduced risk of visceral/vascular injuries, incidental dural tears, and perioperative infections have been reported. However, approach-related complications such as motor and sensory deficits remain a concern. In well-indicated patients, LLIF can be a safe procedure used for a variety of indications.

Morphometric Analysis of the Retroperitoneal Vessels With Respect to Lateral Access Surgery in Adult Scoliosis

STUDY DESIGN

Cross-sectional study reviewing 62 magnetic resonance imaging or computed tomography scans from consecutive adult patients with scoliotic spinal deformity in the thoracolumbar spine.

OBJECTIVE

To investigate the variation in anatomic position of retroperitoneal vessels in relationship to curve direction, location, magnitude, and axial rotation of curves in adult scoliosis.

SUMMARY OF BACKGROUND DATA

The minimally invasive lateral approach to the thoracolumbar spine avoids manipulation of abdominal and retroperitoneal structures and decreases risk of injury to paraspinal musculature. In adult patients with scoliosis, the varying anatomic relationship between retroperitoneal vessels and intervertebral disk spaces can increase the risk of vascular injury.

MATERIALS AND METHODS

Axial images were used to measure the anterior-posterior diameter of the inferior vertebral endplate with respect to the disk space perpendicular to the widest length of the disk. The overlap of the retroperitoneal vessels with the endplate were measured at the cephalad end vertebra, apex, and caudad end vertebra of each curve. Overlap and accessible disk space for individual disk spaces were also measured.

RESULTS

There was a significant difference in percentage overlap of the apex and cephalad vertebral endplate and inferior vena cava in right versus left-sided curves (P=0.002). Overlap between the inferior vertebral endplate and inferior vena cava at the cephalad, apex, and caudad end of the curve was significantly different between thoracolumbar and lumbar curves (P<0.05). Axial rotation significantly affected vessel overlap at multiple curve locations. There was a statistically significant difference in accessible disk space when approaching the curve from the concavity versus convexity.

CONCLUSIONS

Overlap between retroperitoneal vessels and inferior vertebral endplates at the disk level in scoliotic spines varies significantly with direction of the curvature, level of the deformity, and degree of axial rotation. There is decreased accessible disk space and increased vessel overlap on the concavity of the curve. Surgeons, as usual, will take an individualized case by case approach to avoid approach-related vascular complications, but the general relationships reported in this study can guide side of approach.

Anterior cage dislodgement in posterior lumbar interbody fusion: a review of 12 patients

OBJECTIVE Interbody fusion cages are widely used to achieve initial fixation and secure spinal fusion; however, there are certain technique-related complications. Although anterior cage dislodgement can cause major vascular injury, the incidence is extremely rare. Here, the authors performed a review of anterior cage dislodgement following posterior lumbar interbody fusion (PLIF) surgery. METHODS The authors retrospectively reviewed the cases of 4625 patients who had undergone PLIF at 6 institutions between December 2007 and March 2015. They investigated the incidence and causes of surgery-related anterior cage dislodgement, salvage mechanisms, and postoperative courses. RESULTS Anterior cage dislodgement occurred in 12 cases (0.26%), all of which were caused by technical errors. In 9 cases, excessive cage impaction resulted in dislodgement. In 2 cases, when the cage on the ipsilateral side was inserted, it interacted and pushed out the other cage on the opposite side. In 1 case, the cage was positioned in an extreme lateral and anterior part of the intervertebral disc space, and it postoperatively dislodged. In 3 cases, the cage was removed in the same operative field. In the remaining 9 cases, CT angiography was performed postoperatively to assess the relationship between the dislodged cage and large vessels. Dislodged cages were conservatively observed in 2 cases. In 7 cases, the cage was removed because it was touching or compressing large vessels, and an additional anterior approach was selected. In 2 patients, there was significant bleeding from an injured inferior vena cava. There were no further complications or sequelae associated with the dislodged cages during the follow-up period. CONCLUSIONS Although rare, iatrogenic anterior cage dislodgement following a PLIF can occur. The authors found that technical errors made by experienced spine surgeons were the main causes of this complication. To prevent dislodgement, the surgeon should be cautious when inserting the cage, avoiding excessive cage impaction and ensuring cage control. Once dislodgement occurs, the surgeons must immediately address this difficult complication. First, the possibility of a large vessel injury should be considered. If the patient's vital signs are stable, the surgeon should continue with the surgery without cage removal and perform CT angiography postoperatively to assess the cage location. Blind maneuvers should be avoided when the surgical site cannot be clearly viewed. When the cage compresses or touches the aortic artery or vena cava, it is better to remove the cage to avoid late-onset injury to major vessels. When the cage does not compress or touch vessels, its removal is controversial. The risk factors associated with performing another surgery should be evaluated on a case-by-case basis.

The Oblique Anterolateral Approach to the Lumbar Spine Provides Access to the Lumbar Spine With Few Early Complications

BACKGROUND

During the last 20 years several less-invasive anterior approaches to the lumbar spine have become standard, including the extreme lateral transpsoas approach. Although it is associated with a lower risk of vascular injury compared with anterior midline approaches, neuromonitoring is considered mandatory to avoid neurologic complications. Interestingly, despite neuromonitoring, the reported risk of neurologic deficits with the extreme lateral transpsoas approach is greater than observed with other anterior approaches. An alternative lateral, oblique, psoas-sparing approach, recently named the oblique lumbar interbody fusion, uses the anatomic pathway between the abdominal vessels anteriorly and the lumbar plexus laterally to decrease the risk of neurologic and vascular injury; however, as yet, little on this new approach has been reported.

QUESTIONS/PURPOSES

We asked: what proportion of patients experienced (1) perioperative complications (overall complications), (2) vascular complications, and (3) neurologic complications after less-invasive anterior lumbar interbody fusion through the oblique lumbar interbody approach at one high-volume center?

METHODS

We performed a chart review of intra- and perioperative complications of all patients who had undergone minimally invasive anterior lumbar interbody fusion through a lateral psoas-sparing approach from L1 to L5 during a 12-year period (1998-2010). During the study period, the oblique, psoas-sparing approach was the preferred approach of the participating surgeons in this study, and it was performed in 812 patients, all of whom are studied here, and all of whom have complete data for assessment of the short-term (inpatient-only) complications that we studied. In general, we performed this approach whenever possible, although it generally was avoided when a patient previously had undergone an open retro- or transperitoneal abdominal procedure, or previous implantation of hernia mesh in the abdomen. During the study period, posterior fusion techniques were used in an additional 573 patients instead of the oblique lumbar interbody fusion when we needed to decompress the spinal canal beyond what is possible through the anterior approach. In case of spinal stenosis calling for fusion in combination with a high disc space, severe endplate irregularity, or severe biomechanical instability, we combined posterior decompression with oblique lumbar interbody fusion in 367 patients. Complications were evaluated by an independent observer who was not involved in the decision-making process, the operative procedure, nor the postoperative care by reviewing the inpatient records and operative notes.

RESULTS

A total of 3.7% (30/812) of patients who underwent the oblique lumbar interbody fusion experienced a complication intraoperatively or during the hospital stay. During the early postoperative period there were two superficial (0.24%) and three deep (0.37%) wound infections and five superficial (0.62%) and six deep (0.86%) hematomas. There were no abdominal injuries or urologic injuries. The percentage of vascular complications was 0.37% (n = 3). The percentage of neurologic complications was 0.37% (n = 3).

CONCLUSIONS

The risk of vascular complications after oblique lumbar interbody fusion seems to be lower compared with reported risk for anterior midline approaches, and the risk of neurologic complications after oblique lumbar interbody fusion seems to be lower than what has been reported with the extreme lateral transpsoas approach; however, we caution readers that head-to-head studies will need to be performed to confirm our very preliminary comparisons and results with the oblique psoas-sparing approach. Similarly, future studies will need to evaluate this approach in terms of later-presenting complications, such as infection and pseudarthrosis formation, which could not be assessed using this inpatient-only approach. Nevertheless, with the results of this study the oblique psoas-sparing approach can be described as a less-invasive alternative for anterior lumbar fusion surgery from L1 to L5 with a low risk of vascular and neurologic damage and without costly intraoperative neuromonitoring tools.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Biomechanical evaluation of lateral lumbar interbody fusion with secondary augmentation

OBJECTIVE Lateral lumbar interbody fusion (LLIF) has emerged as a popular method for lumbar fusion. In this study the authors aimed to quantify the biomechanical stability of an interbody implant inserted using the LLIF approach with and without various supplemental fixation methods, including an interspinous plate (IP). METHODS Seven human cadaveric L2-5 specimens were tested intact and in 6 instrumented conditions. The interbody implant was intended to be used with supplemental fixation. In this study, however, the interbody was also tested without supplemental fixation for a relative comparison of these conditions. The instrumented conditions were as follows: 1) interbody implant without supplemental fixation (LLIF construct); and interbody implant with supplemental fixation performed using 2) unilateral pedicle screws (UPS) and rod (LLIF + UPS construct); 3) bilateral pedicle screws (BPS) and rods (LLIF + BPS construct); 4) lateral screws and lateral plate (LP) (LLIF + LP construct); 5) interbody LP and IP (LLIF + LP + IP construct); and 6) IP (LLIF + IP construct). Nondestructive, nonconstraining torque (7.5 Nm maximum) induced flexion, extension, lateral bending, and axial rotation, whereas 3D specimen range of motion (ROM) was determined optoelectronically. RESULTS The LLIF construct reduced ROM by 67% in flexion, 52% in extension, 51% in lateral bending, and 44% in axial rotation relative to intact specimens (p < 0.001). Adding BPS to the LLIF construct caused ROM to decrease by 91% in flexion, 82% in extension and lateral bending, and 74% in axial rotation compared with intact specimens (p < 0.001), providing the greatest stability among the constructs. Adding UPS to the LLIF construct imparted approximately one-half the stability provided by LLIF + BPS constructs, demonstrating significantly smaller ROM than the LLIF construct in all directions (flexion, p = 0.037; extension, p < 0.001; lateral bending, p = 0.012) except axial rotation (p = 0.07). Compared with the LLIF construct, the LLIF + LP had a significant reduction in lateral bending (p = 0.012), a moderate reduction in axial rotation (p = 0.18), and almost no benefit to stability in flexion-extension (p = 0.86). The LLIF + LP + IP construct provided stability comparable to that of the LLIF + BPS. The LLIF + IP construct provided a significant decrease in ROM compared with that of the LLIF construct alone in flexion and extension (p = 0.002), but not in lateral bending (p = 0.80) and axial rotation (p = 0.24). No significant difference was seen in flexion, extension, or axial rotation between LLIF + BPS and LLIF + IP constructs. CONCLUSIONS The LLIF construct that was tested significantly decreased ROM in all directions of loading, which indicated a measure of inherent stability. The LP significantly improved the stability of the LLIF construct in lateral bending only. Adding an IP device to the LLIF construct significantly improves stability in sagittal plane rotation. The LLIF + LP + IP construct demonstrated stability comparable to that of the gold standard 360° fixation (LLIF + BPS).

Direct lesion and repair of a common iliac vein during XLIF approach

PURPOSE

Description of a case of direct intraoperative lesion and repair of a major vascular injury of common iliac vein during an extreme lateral interbody fusion L4-L5 procedure.

METHODS

A 69-year-old female who was operated for L4-L5 spondilolysthesis suffered a major vascular injury of a vein. The high cava bifurcation and inadequate pre-operative analysis of the radiological documentation resulted in the lesion. The lesion was successfully repaired and the patient did not suffer post-operative sequelae.

RESULTS

The repair was successful although the index spine procedure was not ended. Detailed pre-operative planning, based on radiological examination of vascular structures, should be a mandatory step prior to this specific surgical approach.

CONCLUSION

Although safer than anterior retroperitoneal approach, extreme lateral interbody fusion still bears risk for major vascular injury.