Open anterior approaches for lumbar spine procedures

An Update in Complication Rates Associated With Anterior Lumbar Surgery: A Systematic Review and Meta-Analysis

STUDY DESIGN

Systematic Review and meta-analysis.

OBJECTIVE

To conduct an updated systematic review and meta-analysis of complications associated with different anterior fusion techniques/approaches and adjuvant resources (i.e., computed tomography angiography (CTA), rhBMP-2, and access surgeons).

METHODS

A systematic review was conducted from 1/1/2014-4/1/2024 for studies evaluating the incidence of complications associated with anterior lumbar procedures. Comparisons of complications were made between surgical approach, use of CTA, rhBMP-2, and access surgeons. Meta-analyses were conducted using a generalized linear mixed model.

RESULTS

54 studies were included in the final analysis with 8066 patients and an average follow-up of 31.2 months. The overall complication rate associated with anterior lumbar surgery was 13.1%, including an intraoperative complication rate of 3.8%, postoperative complication rate of 7.4%, infection rate of 1.5%, and reoperation rate of 1.7%. Forest plot analysis showed no significant difference in overall complication rates between open and mini-open techniques, although mini-open techniques were associated with lower overall reoperation rates. The use of CTA was associated with an increase in intraoperative and overall complications, and the use of an access surgeon was associated with a decreased risk of reoperation. The use of rhBMP-2 was not associated with overall complication risk.

CONCLUSIONS

While anterior lumbar surgery provides numerous benefits, surgeons and patients alike should be aware of the complication and safety profile prior to surgery. High quality studies are warranted to help elucidate the true benefit of certain techniques and adjuvant resources in reducing complications.

Lumbar Total Disk Replacement Device Removals and Revisions Performed During a 20-Year Experience with 2141 Patients

STUDY DESIGN

This was a retrospective study with prospective patient contact attempted to collect current data.

OBJECTIVE

The purpose was to investigate the incidence and reasons for lumbar total disk replacement (TDR) removal or revision.

SUMMARY OF BACKGROUND DATA

A concern regarding lumbar TDR was safety, particularly the need for device removal or revision. This may be particularly important considering removal/revision requires repeat anterior exposure with an increased risk of vascular injury.

METHODS

Data were collected for a series of 2141 lumbar TDR patients, beginning with the first case experience in 2000. The mean follow-up was 78.6 months. For each case of device removal/revision, the reason, duration from index surgery, and procedure performed were recorded.

RESULTS

Of 2141 patients, 27 (1.26%) underwent TDR removal or revision. Device removal was performed in 24 patients (1.12%), while three patients underwent revision (0.14%). Of the 24 removals, 12 were due to migration and/or loosening, three developed problems post-trauma, two developed lymphocytic reaction to device materials, two had ongoing pain, and there was one case of each: TDR was too large, vertebral body fracture (osteoporosis), lytic lesion, device subsidence and facet arthrosis, and infection seeded from a chest infection 146 months post-TDR. The three revisions were for Core repositioning (technique error), device repositioning after displacement, and core replacement due to wear/failure. With respect to timing, 37.0% of removals/revisions occurred within one-month postimplantation. Of note, 40.7% of removals/revisions occurred in the first 25 TDR cases performed by individual surgeons. There was one significant vascular complication occurring in a patient whose TDR was removed due to trauma. This was also the only patient among 258 with ≥15-year follow-up who underwent removal/revision.

CONCLUSION

In this large consecutive series, 1.26% of TDRs were removed/revised. The low rate over a 20 year period supports the safety of these devices.

Biomimetic vascularized adipose-derived mesenchymal stem cells bone-periosteum graft enhances angiogenesis and osteogenesis in a male rabbit spine fusion model

Aims

Several artificial bone grafts have been developed but fail to achieve anticipated osteogenesis due to their insufficient neovascularization capacity and periosteum support. This study aimed to develop a vascularized bone-periosteum construct (VBPC) to provide better angiogenesis and osteogenesis for bone regeneration.

Methods

A total of 24 male New Zealand white rabbits were divided into four groups according to the experimental materials. Allogenic adipose-derived mesenchymal stem cells (AMSCs) were cultured and seeded evenly in the collagen/chitosan sheet to form cell sheet as periosteum. Simultaneously, allogenic AMSCs were seeded onto alginate beads and were cultured to differentiate to endothelial-like cells to form vascularized bone construct (VBC). The cell sheet was wrapped onto VBC to create a vascularized bone-periosteum construct (VBPC). Four different experimental materials - acellular construct, VBC, non-vascularized bone-periosteum construct, and VBPC - were then implanted in bilateral L4-L5 intertransverse space. At 12 weeks post-surgery, the bone-forming capacities were determined by CT, biomechanical testing, histology, and immunohistochemistry staining analyses.

Results

At 12 weeks, the VBPC group significantly increased new bone formation volume compared with the other groups. Biomechanical testing demonstrated higher torque strength in the VBPC group. Notably, the haematoxylin and eosin, Masson's trichrome, and immunohistochemistry-stained histological results revealed that VBPC promoted neovascularization and new bone formation in the spine fusion areas.

Conclusion

The tissue-engineered VBPC showed great capability in promoting angiogenesis and osteogenesis in vivo. It may provide a novel approach to create a superior blood supply and nutritional environment to overcome the deficits of current artificial bone graft substitutes.

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.

Mini-Open Intercostal Retroperitoneal Approach for Upper Lumbar Spine Lateral Interbody Fusion

OBJECTIVE

Conventional oblique lumbar interbody fusion (OLIF) approach is possible from the L2/3 to L4/5 levels. However, obstruction of the lower ribs (10th-12th) makes it difficult to maintain disc parallel maneuvers or orthogonal maneuvers. To overcome these limitations, we proposed an intercostal retroperitoneal (ICRP) approach to access the upper lumbar spine. This method does not expose the parietal pleura or require rib resection and employs a small incision.

METHODS

We enrolled patients who underwent a lateral interbody procedure on the upper lumbar spine (L1/2/3). We compared the incidence of endplate injury between conventional OLIF and ICRP approaches. In addition, by measuring the rib line, the difference in endplate injury according to rib location and approach was analyzed. We also analyzed the previous period (2018-2021) and the year 2022, when the ICRP has been actively applied.

RESULTS

A total of 121 patients underwent lateral interbody fusion to the upper lumbar spine (OLIF approach, 99 patients; ICRP approach, 22 patients). Endplate injuries occurred in 34 of 99 (34.3%) and 2 of 22 patients (9.1%) during the conventional and ICRP approaches, respectively (p = 0.037; odds ratio, 5.23). When the rib line was located at the L2/3 disc or L3 body, the endplate injury rate was 52.6% (20 of 38) for the OLIF approach but 15.4% (2 of 13) for the ICRP approach. Since 2022, the proportion of OLIF including L1/2/3 levels has increased 2.9-fold.

CONCLUSION

The ICRP approach is effective in reducing the incidence of endplate injury in patients with a relatively lower rib line, without pleural exposure or rib resection.

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.

Predictors of the need for rib resection in minimally invasive retroperitoneal approach for oblique lateral interbody fusion at upper lumbar spine (L1-2 and L2-3)

BACKGROUND

This study aimed to identify factors that can predict the need for rib resection in a minimally invasive, oblique retroperitoneal approach for upper lumbar interbody fusion (OLIF at L1-3) using modern tubular retractors.

METHODS

Eighty-six patients, who underwent L1-2 and/or L2-3 OLIF at a single institution, were included. Decision for rib resection was made through intraoperative fluoroscopic view (true lateral view of the desired level). Patients were divided into two groups according to rib resection (rib resection and non-rib resection groups). Baseline demographics, surgical and radiographic data, including coronal/sagittal spinopelvic parameters and perioperative complications, were compared between the groups. Logistic regression analysis was performed to identify the factors predicting the need for rib resection.

RESULTS

The study cohort comprised 31 patients in the rib resection group and 55 patients in the non-rib resection group. There was no significant inter-group difference in terms of the baseline demographics. A total of 79% patients undergoing the two-level (both L1-2 and L2-3) procedures were rib-resected, while 81.6% of the patients undergoing the L2-3 level alone were not rib-resected. Endplate injuries occurred more commonly in the non-rib resection group (3% vs. 14%). Pleural laceration was observed in 6% of the patients in the rib resection group. The mean T10-L2 kyphosis was larger in the rib resection group than in the non-rib resection group (14.9° vs. 6.6°, P = 0.031). Multivariate logistic regression analysis identified the following independent predictors of the need for rib resection: an L1-2 inclusive procedure; T10-L2 kyphosis > 15.9°; and the apex of the coronal curve located above L2.

CONCLUSION

The need for rib resection should be expected when performing L1-2 inclusive procedure. Even in the L2-3 alone case, aggressive decision-making for intraoperative rib resection might be required for an appropriate tubular retractor position, especially for patients with thoracolumbar kyphosis and apex vertebra of the major coronal curve located above L2.

Clinical presentation and surgical anatomy of sympathetic nerve injury during lumbar spine surgery: a narrative review

BACKGROUND AND OBJECTIVE

To highlight the surgical anatomy, procedural variations, presentation, and management of sympathetic nerve injury after surgery of the lumbar spine.

METHODS

PubMed and Google Scholar were searched for publications that were completed between 1951 and 2021. Relevant full-text articles published in the English language were selected and critically reviewed.

KEY CONTENT AND FINDINGS

Sympathetic injury is a highly variable postsurgical complication with a greater incidence after an anterior or oblique approach to the lumbar spine compared to posterior and lateral approaches. The direct and extreme lateral approaches reduce the need to disturb sympathetic nerves thus reducing the risk of complications. It can present in multiple manners, including complex regional pain syndrome (CRPS) and retrograde ejaculation. These complications can be transient and resolve spontaneously or be treated with medications, physical therapy, and spinal blocks. The severity of the conditions and extent of recovery can vary drastically, with some patients never fully recovering.

CONCLUSIONS

To access the lumbar spine, there are operational approaches and techniques that should be used to decrease the risk of intraoperative injury. It is crucial to understand the advantages and risks to different approaches and take the necessary steps to minimize complications. Early identification of dysfunction and adequate management of symptoms are imperative to effectively manage patients with lumbar sympathetic trunk and sympathetic nerve fiber injuries.

Complication Avoidance in Surgical Management of Vertebral Column Tumors

The surgical management of spinal tumors has grown increasingly complex as treatment algorithms for both primary bone tumors of the spine and metastatic spinal disease have evolved in response to novel surgical techniques, rising complication rates, and additional data concerning adjunct therapies. In this review, we discuss actionable interventions for improved patient safety in the operative care for spinal tumors. Strategies for complication avoidance in the preoperative, intraoperative, and postoperative settings are discussed for approach-related morbidities, intraoperative hemorrhage, wound healing complications, cerebrospinal fluid (CSF) leak, thromboembolism, and failure of instrumentation and fusion. These strategies center on themes such as pre-operative imaging review and medical optimization, surgical dissection informed by meticulous attention to anatomic boundaries, and fastidious wound closure followed by thorough post-operative care.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Genitourinary complications in orthopaedic surgery

Genitourinary complications following orthopaedic intervention are uncommon but well-described occurrences and exist on a spectrum of severity. These complications vary depending on the anatomic location and surgical approach, with surgery of the spine, hip, and pelvis of particular concern. Injuries to the urinary tract may present acutely with urinary retention or hematuria. However, they often have a delayed presentation with severe complications such as urinary fistula and recurrent infection. Delayed presentations may place the onus of timely and proper diagnosis on the orthopaedic provider, who may serve as the patient's primary source of long-term follow-up. Detailed knowledge of anatomy and at-risk structures is key to both preventing and identifying injury. Although iatrogenic injury is not always avoidable, early identification can help to facilitate timely evaluation and management to prevent long-term complications such as bladder dysfunction, obstructive renal injury, sexual dysfunction, and chronic pain.  Keywords: urologic injury, bladder injury, genitourinary injury, hip arthroplasty, pelvic ring injuries, spine surgery.

Technique for Exposing Lumbar Discs in Anterior Approach Using Steinmann Wires: Arthroplasties or Arthrodesis

BACKGROUND

Due to increasing longevity, the incidence of degenerative lumbar disc diseases has increased, and surgical treatment is often necessary. In this context, the anterior approach becomes an important technique. However, one of the main limitations of this method is the need for dedicated retractors, which requires larger incisions for its positioning and increases the cost of the procedure. The objective of the present study was to describe a technique for retracting abdominal structures by anterior approaches to the lumbar spine using Steinmann wires.

METHODS

This manuscript consists of a technique description of anterior approach for lumbar spine.

RESULTS

Surgical treatment of degenerative lumbar spine disease is often necessary when the patients have symptoms refractory to conservative treatments. Many of them will be candidates for surgical treatment with anterior approach, either for arthrodesis/anterior lumbar interbody fusion or arthroplasty. Small incisions are performed for positioning the modified Langenbeck retractors and the Steinmann wires. These retractors are easily positioned and provide good exposure of the lumbar discs making it possible to implant appropriate cages for restoring the necessary height, lordosis, and sagittal balance.

CONCLUSIONS

The technique described is safe, inexpensive, and reproducible. Simple and easily accessible instruments are required in most hospital complexes.

Lumbar Interbody Fusion: Techniques, Pearls and Pitfalls

Lumbar interbody fusion (LIF) is an effective and popular surgical procedure for the management of various spinal pathologies, especially degenerative diseases. Currently, LIF can be performed with posterior, transforaminal, anterior, and lateral approaches by open surgery or minimally invasive surgery (MIS). Each technique has its own advantages and disadvantages. In general, posterior LIF is a well-established procedure with good fusion rates and low complication rates but is limited by the possibility of iatrogenic injury to the neural structures and paraspinal muscles. Transforaminal LIF is frequently performed using an MIS technique and has an advantage of reducing these iatrogenic injuries. Anterior LIF (ALIF) can restore the disk height and sagittal alignment but has inherent approach-related challenges such as visceral and vascular complications. Lateral LIF and oblique LIF are performed using an MIS technique and have shown postoperative outcomes similar to ALIF; however, these approaches carry a risk of injury to psoas, lumbar plexus, and vascular structures. Herein, we provide a detailed description of the surgical procedures of each LIF technique. We shall then consider the pearls and pitfalls, as well as propose surgical indications and contraindications based on the available evidence in the literatures.

State of the art review: Vertebral Osteotomies for the management of Spinal Deformity

Spinal deformity is a complex condition caused by various etiologies (degenerative, neuromuscular, congenital, developmental, traumatic, neoplastic, idiopathic) leading to clinical deformity, axial back pain, and neurologic deficits. Patients presenting with severe deformities require vertebral osteotomies to achieve the necessary curve correction for radiographic and clinical improvement. The three major vertebral osteotomy techniques commonly used at this time are the posterior column osteotomy (PCO), pedicle subtraction osteotomy (PSO), and vertebral column resection (VCR). The different vertebral osteotomies have unique merits and pitfalls that need to be addressed during preoperative planning to achieve maximum benefit while limiting or avoiding possible complications. The more difficult vertebral osteotomies have a steeper learning curve and requires extensive pre, intra and postoperative management of the patient. This review will aim to discuss the indications, surgical techniques, and clinical outcomes for each of these different vertebral osteotomy techniques with illustrative cases.

Development and validation of a novel scoring tool for predicting facility discharge after elective posterior lumbar fusion

BACKGROUND CONTEXT

Discharge to acute/intermediate care facilities is a common occurrence after posterior lumbar fusion and can be associated with increased costs and complications after these procedures. This is particularly relevant with the growing popularity of bundled payment plans, creating a need to identify patients at greatest risk.

PURPOSE

To develop and validate a risk-stratification tool to identify patients at greatest risk for facility discharge after open posterior lumbar fusion.

STUDY DESIGN

Retrospective cohort study.

PATIENT SAMPLE

Patients were queried using separate databases from the institution of study and the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) for all patients undergoing open lumbar fusion between 2011 and 2018.

OUTCOME MEASURES

Discharge to intermediate care and/or rehabilitation facilities.

METHODS

Using an 80:20 training and testing NSQIP data split, collected preoperative demographic and operative variables were used in a multivariate logistic regression to identify potential risk factors for postoperative facility discharge, retaining those with a p value <.05. A nomogram was generated to develop a scoring system from this model, with probability cutoffs determined for facility discharge. This model was subsequently validated within the NSQIP database, in addition to external validation at the institution of study. Overall model performance and calibration was assessed using the Brier score and calibration plots, respectively.

RESULTS

A total of 11,486 patients (10,453 NSQIP, 1,033 local cohort) were deemed eligible for study, of which 16.1% were discharged to facilities (16.7% NSQIP, 9.6% local cohort). Utilizing training data, age (p<.001), body mass index (p<.001), female sex (p<.001), diabetes (p=.043), peripheral vascular disease (p=.001), cancer (p=.010), revision surgery (p<.001), number of levels fused (p<.001), and spondylolisthesis (p=.049) were identified as significant risk factors for facility discharge. The area under the receiver operating characteristic curve (AUC) indicated a strong predictive model (AUC=0.750), with similar predictive ability in the testing (AUC=0.757) and local data sets (AUC=0.773). Using this tool, patients identified as low- and high-risk had a 7.94% and 33.28% incidence of facility discharge in the testing data set, while rates of 4.44% and 16.33% were observed at the institution of study.

CONCLUSIONS

Using preoperative variables as predictors, this scoring system demonstrated high efficiency in risk-stratifying patients with an approximate four to fivefold difference in rates of facility discharge after posterior lumbar fusion. This tool may help inform medical decision-making and guide reimbursement under bundled-care repayment plans.

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.

Exploring perioperative complications of anterior lumber interbody fusion in patients with a history of prior abdominal surgery: A retrospective cohort study

BACKGROUND CONTEXT

Anterior lumbar interbody fusion (ALIF) exposes the anterior aspect of the spine through a retroperitoneal approach. Access to the anterior spine requires mobilization of intra-abdominal viscera/vasculature, which can become complicated as scarring and/or adhesions develop from prior abdominal surgical interventions, increasing risk of intraoperative complications. The literature suggests that "significant prior abdominal surgery" is a relative contraindication of ALIF surgery; however, there is no consensus within the literature as to what defines "major/significant" abdominal surgeries. Additionally, the association between the number of prior abdominal surgeries and perioperative complications in ALIF surgery has not been explored within the literature.

PURPOSE

This study seeks to explore the association between perioperative complications of ALIF surgery and the type (major and/or minor) and number of prior abdominal surgeries.

DESIGN

A retrospective cohort study was performed to examine perioperative complications in ALIF patients with or without prior history of abdominal surgery.

PATIENT SAMPLE

All consecutive patients undergoing ALIF with or without a history of prior abdominal surgery from 2008 to 2018 at a single tertiary center were evaluated. Patients under the age of 18, patients with spinal malignancy, or patients who had ALIF above L3 were excluded.

OUTCOME MEASURES

Perioperative complications included intraoperative complications during ALIF surgery and postoperative complications within 90 days of ALIF surgery. Intraoperative complications include vascular injury, ureter injury, retroperitoneal hematoma, etc. Postoperative complications include urinary tract infection, revision of abdominal scar, ileus, deep vein thrombosis, pulmonary embolism, etc. Other outcome measures include readmission within 90 days, length of ALIF surgery, and length of hospital stay.

METHODS

Electronic medical records of 660 patients who underwent ALIF between 2008 and 2018 were retrospectively reviewed. Patient demographics, Charleston Comorbidity Index (CCI), level of fusion, past abdominal surgical history, use of access surgeon during exposure, intraoperative, and postoperative complications were collected. Predictors of intraoperative and postoperative complications were analyzed using simple and multivariable logistic regression. Statistical analysis was performed using JMP 14.0 (SAS, Cary, NC, USA) software.

RESULTS

After controlling for age, length of ALIF, gender, multilevel ALIF, and the use of an access surgeon, there was no significant association between the type of prior abdominal surgery (major and/or minor) and intraoperative complications on multivariable logistic regression analysis (Minor: odds ratio [OR]=1.68; 95% confidence interval [CI]: 0.58-4.86 & Major: OR=1.99; 95% CI: 0.80-4.91). On multivariable logistic regression, the odds of developing an intraoperative complication increases by 52% for each additional prior abdominal surgery after adjusting for age, length of ALIF, gender, multilevel ALIF, and the use of an access surgeon (OR=1.52, 95% CI: 1.10-2.11). Iliac vein laceration was the most common intraoperative complication (n=27, 4%). Neither the type (major and/or minor) nor the number of prior abdominal surgeries were significant predictors of postoperative complications (Minor: OR=1.29; 95% CI: .72-2.31, Major: OR=1.24; 95% CI: 0.77-2.00, & Number: OR=1.03; 95% CI: .84-1.26).

CONCLUSION

With each additional prior abdominal surgery, accumulation of scarring and adhesions can likely obscure anatomical landmarks and increase the risk of developing an intraoperative complication. Therefore, the number of prior abdominal surgeries should be taken into consideration during planning and operative exposure of the anterior spine via a retroperitoneal approach.

Retroperitoneal Extrapleural Approach for Corpectomy of the First Lumbar Vertebra : Technique and Outcome

Objective

Corpectomy of the first lumbar vertebra (L1) for the management of different L1 pathologies can be performed using either an anterior or posterior approach. The aim of this study was to evaluate the usefulness of a retroperitoneal extrapleural approach through the twelfth rib for performing L1 corpectomy.

Methods

Thirty consecutive patients underwent L1 corpectomy between 2010 and 2016. The retroperitoneal extrapleural approach through the 12th rib was used in all cases to perform single-stage anterior L1 corpectomy, reconstruction and anterior instrumentation, except for in two recurrent cases in which posterior fixation was added. Visual analogue scale (VAS) was used for pain intensity measurement and ASIA impairment scale for neurological assessment. The mean follow-up period was 14.5 months.

Results

The sample included 18 males and 12 females, and the mean age was 40.3 years. Twenty patients (67%) had sensory or motor deficits before the surgery. The pathologies encountered included traumatic fracture in 12 cases, osteoporotic fracture in four cases, tumor in eight cases and spinal infection in the remaining six cases. The surgeries were performed from the left side, except in two cases. There was significant improvement of back pain and radicular pain as recorded by VAS. One patient exhibited postoperative neurological deterioration due to bone graft dislodgement. All patients with deficits at least partially improved after the surgery. During the follow-up, no hardware failures or losses of correction were detected.

Conclusion

The retroperitoneal extrapleural approach through the 12th rib is a feasible approach for L1 corpectomy that can combine adequate decompression of the dural sac with effective biomechanical restoration of the compromised anterior load-bearing column. It is associated with less pulmonary complication, no need for chest tube, no abdominal distention and rapid recovery compared with other approaches.

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.

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

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

Evaluation of Two Novel Integrated Stand-Alone Spacer Designs Compared with Anterior and Anterior-Posterior Single-Level Lumbar Fusion Techniques: An In Vitro Biomechanical Investigation

Study Design

In vitro biomechanical investigation.

Purpose

To compare the biomechanics of integrated three-screw and four-screw anterior interbody spacer devices and traditional techniques for treatment of degenerative disc disease.

Overview of Literature

Biomechanical literature describes investigations of operative techniques and integrated devices with four dual-stacked, diverging interbody screws; four alternating, converging screws through a polyether-ether-ketone (PEEK) spacer; and four converging screws threaded within the PEEK spacer. Conflicting reports on the stability of stand-alone devices and the influence of device design on biomechanics warrant investigation.

Methods

Fourteen cadaveric lumbar spines were divided randomly into two equal groups (n=7). Each spine was tested intact, after discectomy (injured), and with PEEK interbody spacer alone (S), anterior lumbar plate and spacer (AP+S), bilateral pedicle screws and spacer (BPS+S), circumferential fixation with spacer and anterior lumbar plate supplemented with BPS, and three-screw (SA3s) or four-screw (SA4s) integrated spacers. Constructs were tested in flexion-extension (FE), lateral bending (LB), and axial rotation (AR). Researchers performed one-way analysis of variance and independent t-testing (p≤0.05).

Results

Instrumented constructs showed significantly decreased motion compared with intact except the spacer-alone construct in FE and AR (p≤0.05). SA3s showed significantly decreased range of motion (ROM) compared with AP+S in LB (p≤0.05) and comparable ROM in FE and AR. The three-screw design increased stability in FE and LB with no significant differences between integrated spacers or between integrated spacers and BPS+S in all loading modes.

Conclusions

Integrated spacers provided fixation statistically equivalent to traditional techniques. Comparison of three-screw and four-screw integrated anterior lumbar interbody fusion spacers revealed no significant differences, but the longer, larger-diameter interbody spacer with three-screw design increased stabilization in FE and LB; the diverging four-screw design showed marginal improvement during AR.

Incorporation of Anterior Lumbosacral Spine Exposure into a General Surgical Practice

Many spine surgeons enlist the aid of an “access surgeon” to provide anterior exposure of the lumbosacral spine. We proposed that a single, community hospital general surgery practice can successfully develop an anterior spine exposure program with acceptable clinical outcomes. One hundred and forty-three consecutive anterior exposures were performed between 2008 and 2014. Morbidity and 30-day mortality were recorded. The effects of American Society of Anesthesiologists Physical Status classification (ASA class) and number of levels exposed on length of stay (LOS) and estimated blood loss (EBL) was reported. The growth of the program during this period was also evaluated. During the six-year period, there were nine (6.3%) major complications and 17 (11.9%) minor complications with no 30-day mortality. The mean LOS was similar for one-level and two-level exposures (3.8 days). Mean LOS was higher in ASA III patients (4.4 days) than ASA I (2.9 days) or ASA II (3.2 days). Mean EBL for one-level exposures (336.3 mL) was not significantly different than EBL for two-level exposures (425.9 mL). EBLs in ASA class III patients were greater than in class I and class II patients. The program began in July of 2008 with a single spine surgeon and one operation that year. A high of 54 procedures, with seven different spine surgeons, was recorded in 2013. A single, community hospital general surgery practice can successfully develop an anterior approach to spine exposure program with acceptable clinical outcomes and with sustained growth of the program.

Transforaminal Lumbar Interbody Fusion Versus Mini-open Anterior Lumbar Interbody Fusion With Oblique Self-anchored Stand-alone Cages for the Treatment of Lumbar Disc Herniation: A Retrospective Study With 2-year Follow-up

STUDY DESIGN

A retrospective study.

OBJECTIVE

The aim of this study was to evaluate the clinical and radiological outcomes of mini-open ALIF (MO-ALIF) with self-anchored stand-alone cages for the treatment of lumbar disc herniation in comparison with transforaminal lumbar interbody fusion (TLIF).

SUMMARY OF BACKGROUND DATA

Currently, whether ALIF is superior to TLIF for the treatment of lumbar disc herniation remains controversial.

METHODS

This study retrospectively reviewed 82 patients who underwent MO-ALIF with self-anchored standalone cages (n = 42) or TLIF (n = 40) for the treatment of lumbar disc herniation between April 2013 and October 2014. Patient demographics, intraoperative parameters, and perioperative complications were collated. Clinical outcomes were evaluated using the visual analog scale (VAS) scoring, the Oswestry Disability Index (ODI) for pain in the leg and back, and radiological outcomes, including fusion, lumbar lordosis (LL), disc height (DH), and cage subsidence were evaluated at each follow-up for up to 2 years.

RESULTS

Patients who underwent TLIF had a significantly higher volume of blood loss (295.2 ± 81.4 vs. 57.0 ± 15.2 mL) and longer surgery time (130.7 ± 45.1 vs. 60.4 ± 20.8 min) than those who had MO-ALIF. Compared with baseline, both groups had significant improvements in the VAS and ODI scores and DH and LL postoperatively, though no significant difference was found between the two groups regarding these indexes. All patients reached solid fusion at the final follow-up in both groups. Three patients (3/42) with three levels (3/50) suffered from cage subsidence in the MO-ALIF group; meanwhile, no cage subsidence occurred in the TLIF group.

CONCLUSION

MO-ALIF with self-anchored stand-alone cages is a safe and effective treatment of lumbar disc herniation with less surgical trauma and similar clinical and radiological outcomes compared with TLIF.

LEVEL OF EVIDENCE

3.

Transperitoneal Intervascular Approach for Repair of the Lumbar Spine

This report describes a novel anterior surgical approach to the midlumbar spine. A transperitoneal dissection separating the tissue planes between the infrarenal vena cava and abdominal aorta allows for ample exposure in the reconstruction of midlumbar vertebral body fractures.

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

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

Evolution of Design of Interbody Cages for Anterior Lumbar Interbody Fusion

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

Evaluation of Anterior Vertebral Interbody Fusion Using Osteogenic Mesenchymal Stem Cells Transplanted in Collagen Sponge

STUDY DESIGN

The study used a rabbit model to achieve anterior vertebral interbody fusion using osteogenic mesenchymal stem cells (OMSCs) transplanted in collagen sponge.

OBJECTIVE

We investigated the effectiveness of graft material for anterior vertebral interbody fusion using a rabbit model by examining the OMSCs transplanted in collagen sponge.

SUMMARY OF BACKGROUND DATA

Anterior vertebral interbody fusion is commonly performed. Although autogenous bone graft remains the gold-standard fusion material, it requires a separate surgical procedure and is associated with significant short-term and long-term morbidity. Recently, mesenchymal stem cells from bone marrow have been studied in various fields, including posterolateral spinal fusion. Thus, we hypothesized that cultured OMSCs transplanted in porous collagen sponge could be used successfully even in anterior vertebral interbody fusion.

METHODS

Forty mature male White Zealand rabbits (weight, 3.5-4.5 kg) were randomly allocated to receive one of the following graft materials: porous collagen sponge plus cultured OMSCs (group I); porous collagen sponge alone (group II); autogenous bone graft (group III); and nothing (group IV). All animals underwent anterior vertebral interbody fusion at the L4/L5 level. The lumbar spine was harvested en bloc, and the new bone formation and spinal fusion was evaluated using radiographic analysis, microcomputed tomography, manual palpation test, and histologic examination at 8 and 12 weeks after surgery.

RESULTS

New bone formation and bony fusion was evident as early as 8 weeks in groups I and III. And there was no statistically significant difference between 8 and 12 weeks. At both time points, by microcomputed tomography and histologic analysis, new bone formation was observed in both groups I and III, fibrous tissue was observed and there was no new bone in both groups II and IV; by manual palpation test, bony fusion was observed in 40% (4/10) of rabbits in group I, 70% (7/10) of rabbits in group III, and 0% (0/10) of rabbits in both groups II and IV.

CONCLUSIONS

These findings suggest that mesenchymal stem cells that have been cultured with osteogenic differentiation medium and loaded with collagen sponge could induce bone formation and anterior vertebral interbody fusion. And the rabbit model we developed will be useful in evaluating the effects of graft materials for anterior vertebral interbody fusion. Further study is needed to determine the most appropriate carrier for OMSCs and the feasibility in the clinical setting.

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

Study Design Retrospective analysis of prospectively collected observational data. Objective To assess the safety and efficacy of anterior lumbar interbody fusion (ALIF) as a salvage option for lumbar pseudarthrosis following failed posterior lumbar fusion surgery. Methods From 2009 to 2013, patient outcome data was collected prospectively over 5 years from 327 patients undergoing ALIF performed by a single surgeon (R.J.M.) with 478 levels performed. Among these, there were 20 cases of failed prior posterior fusion that subsequently underwent ALIF. Visual analog score (VAS), Oswestry Disability Index (ODI), and Short Form 12-item health survey (SF-12) were measured pre- and postoperatively. The verification of fusion was determined by utilizing a fine-cut computed tomography scan at 12-month follow-up. Results There was a significant difference between the preoperative (7.25 ± 0.8) and postoperative (3.1 ± 2.1) VAS scores (p < 0.0001). The ODI scale also demonstrated a statistically significant reduction from preoperative (56.3 ± 16.5) and postoperative (30.4 ± 19.3) scores (p < 0.0001). The SF-12 scores were significantly improved after ALIF salvage surgery: Physical Health Composite Score (32.18 ± 5.5 versus 41.07 ± 9.67, p = 0.0003) and Mental Health Composite Score (36.62 ± 12.25 versus 50.89 ± 10.86, p = 0.0001). Overall, 19 patients (95%) achieved successful fusion. Conclusions Overall, our results suggest that the ALIF procedure results not only in radiographic improvements in bony fusion but in significant improvements in the patient's physical and mental experience of pain secondary to lumbar pseudarthrosis. Future multicenter registry studies and randomized controlled trials should be conducted to confirm the long-term benefit of ALIF as a salvage option for failed posterior lumbar fusion.

Outcomes of anterior lumbar interbody fusion surgery based on indication: a prospective study

BACKGROUND

There is limited information on clinical outcomes after anterior lumbar interbody fusion (ALIF) based on the indications for surgery.

OBJECTIVE

To compare the clinical and radiological outcomes of ALIF for each surgical indication.

METHODS

This prospective clinical study included 125 patients who underwent ALIF over a 2-year period. The patients were evaluated preoperatively and postoperatively. Outcome measures included the Short Form-12, Oswestry Disability Index, Visual Analog Scale, and Patient Satisfaction Index.

RESULTS

After a mean follow-up of 20 months, the clinical condition of the patients was significantly better than their preoperative status across all indications. A total of 108 patients had a Patient Satisfaction Index score of 1 or 2, indicating a successful clinical outcome in 86%. Patients with degenerative disk disease (with and without radiculopathy), spondylolisthesis, and scoliosis had the best clinical response to ALIF, with statistically significant improvement in the Short Form-12, Oswestry Disability Index, and Visual Analog Scale. Failed posterior fusion and adjacent segment disease showed statistically significant improvement in all of these clinical outcome scores, although the mean changes in the Short Form-12 Mental Component Summary, Oswestry Disability Index, and Visual Analog Scale (back pain) were lower. The overall radiological fusion rate was 94.4%. Superior radiological outcomes (fusion >90%) were observed in patients with degenerative disk disease (with and without radiculopathy), spondylolisthesis, and failed posterior fusion, whereas in adjacent segment disease, it was 80%.

CONCLUSION

ALIF is an effective treatment for degenerative disk disease (with and without radiculopathy) and spondylolisthesis. Although results were promising for scoliosis, failed posterior fusion, and adjacent segment disease, further studies are necessary to establish the effectiveness of ALIF in these conditions.

Direct lateral retroperitoneal approach for the surgical treatment of lumbar discitis and osteomyelitis

OBJECT

The medical management of discitis and osteomyelitis with long-term antibiotic therapy and bracing usually results in eradicated infection. Surgical management is appropriate when medical management fails and in some cases with pyogenic deformity or neurological deficit. The success of surgery depends on adequate debridement of the necrotic infected disc and vertebral body, along with anterior column reconstruction and vertebral stabilization. Debridement is typically performed via an anterior retroperitoneal approach, which can necessitate mobilization of the great vessels for proper exposure. Mobilization can be technically difficult and lead to vascular injury. The purpose of this study was to evaluate an alternative technique for the surgical treatment of lumbar discitis and osteomyelitis using a direct lateral retroperitoneal approach, which allows for thorough debridement and anterior column reconstruction while avoiding the need to mobilize the great vessels.

METHODS

A retrospective chart analysis was performed for all patients who had presented with lumbar discitis and osteomyelitis and had undergone surgical management via the direct lateral retroperitoneal approach in the period from 2006 to 2013. Collected data included surgical blood loss, perioperative complications (wound infection, vascular injury, approach-related complications, and neurological injury), need for secondary procedures, microbiological and laboratory results, and efficacy of infection eradication. Imaging studies were reviewed as well.

RESULTS

Ten patients, 7 male and 3 female, underwent this procedure at the authors' institution in the defined period. Average blood loss was 272 ml (range 150-800 ml, with 800 ml in the only 2-level case). There were no vascular injuries. Average follow-up was 680 days, although 4 patients did not complete the follow-up beyond 6 months. Eight patients underwent immediate posterior pedicle screw instrumentation. Two patients did not undergo posterior instrumentation, and one of these developed a kyphotic deformity that required a secondary posterior procedure. Infection was eradicated in all patients according to a history, physical examination, imaging studies, and laboratory parameters (complete blood count, erythrocyte sedimentation rate, and C-reactive protein). One patient developed a painful neuroma at the iliac crest harvest site, and one patient had a retroperitoneal hematoma. Otherwise, there were no approach-related neurological injuries or complications. Neither was there any postoperative surgical site infection.

CONCLUSIONS

The direct lateral approach for the surgical treatment of lumbar discitis and osteomyelitis allows for thorough debridement and spinal reconstruction without the need to mobilize the great vessels. This technique effectively eradicated infection in all cases, with reasonable blood loss and no vascular injuries. This approach should be considered as an alternative to the open anterior approach. The authors recommend posterior instrumentation to prevent the development of kyphosis.

Prior abdominal surgery is associated with an increased risk of postoperative complications after anterior lumbar interbody fusion

STUDY DESIGN

Retrospective medical record review.

OBJECTIVE

The purpose of this study was to determine whether a history of abdominal/pelvic surgery confers an increased risk of retroperitoneal anterior approach-related complications when undergoing anterior lumbar interbody fusion.

SUMMARY OF BACKGROUND DATA

As anterior lumbar interbody fusion gains popularity, both anterior retroperitoneal approach have become increasingly used.

METHODS

The records of 263 patients, who underwent infraumbilical retroperitoneal approach to the anterior aspect of the lower lumbar spine for a degenerative spine condition between 2007 and 2011 were retrospectively reviewed. Patient's demographics, risk factors, preoperative diagnosis, surgical history, level of the anterior fusion, and perioperative complications were collected. Anterior retroperitoneal approach to the spine was carried out by a single general surgeon.

RESULTS

Ninety-seven patients (37%) developed at least 1 complication. Forty-nine percent of patients with a history of abdominal surgery developed a postoperative complication compared with 28% of patients without such history (RR = 1.747, P≤ 0.001). After controlling for other factors such as age, sex, body mass index, diagnostic groups, and preoperative comorbidities (hypertension, diabetes, and smoking status), these differences remained statistically significant. When each type of complication was considered separately, there was a statistically significant difference in the incidence of general complications (RR = 2.384, P = 0.007), instrumentation-related complications (RR = 2.954, P = 0.010), and complications related to the anterior approach (RR = 1.797, P = 0.021).

CONCLUSION

Anterior lumbar interbody fusion via a midline incision and a retroperitoneal approach was associated with 37% overall rate of complication. Patients with a history of abdominal or pelvic surgery are at a higher risk of developing general, instrumentation, and anterior approach-related complications.

Incidence of vascular complications arising from anterior spinal surgery in the thoraco-lumbar spine

STUDY DESIGN

Modern biomaterials and instrumentation have popularised surgery of the thoraco-lumbar spine through an anterior route. The advantage of anterior surgery is that it allows for a direct decompression of the compromised spinal canal. However, the potential for devastating long-term sequelae as a result of complications is high.

PURPOSE

The aim of this study was to give a general overview and identify the incidence of vascular complications.

OVERVIEW OF LITERATURE

There is limited literature describing the overall incidence and complications of anterior spinal surgery.

METHODS

A retrospective review of a prospective database of 1,262 consecutive patients with anterior surgery over a twelve-year period.

RESULTS

In our study, 1.58% (n=20) of patients suffered complications. Injury to a major vessel was encountered in 14 (1.11%) cases, of which nine involved an injury to the common iliac vein. In six cases, the original procedure was abandoned due to a life-threatening vascular injury (n=3) and unfavourable anatomy (n=3).

CONCLUSIONS

The incidence of vascular and other complications in our study was relatively low. Nevertheless, the potential for devastating long-term sequelae as a result of complications remains high. A thorough knowledge and awareness of normal and abnormal anatomy should be gained before attempting such a procedure, and a vascular surgical assistance especially should be readily accessible. We believe use of access surgeons is mandatory in cases with difficult or aberrant anatomy.

Experience with 161 cases of anterior exposure of the thoracic and lumbar spine in an acute care surgery model: impact of exposure level and underlying pathology on morbidity

STUDY DESIGN

Retrospective chart review.

OBJECTIVE

To evaluate the outcomes of anterior exposure of the thoracic and lumbar spine by an acute care surgery service.

SUMMARY OF BACKGROUND DATA

Spine surgeons typically require an "approach surgeon" to provide anterior exposure of the thoracic and lumbar spine. We hypothesized that a dedicated acute care surgery service can perform those operations with acceptable morbidity and mortality.

METHODS

A retrospective review of 161 trauma and nontrauma patients was performed. All cases were performed at a level I trauma center with a dedicated acute care surgery service. In-hospital morbidity and mortality were evaluated. A brief description of the operative techniques used by our group is also provided.

RESULTS

Of the 161 patients, 59 (37%) were trauma patients. Ninety-three patients (58%) had anterolateral retroperitoneal exposure of the thoracic and lumbar spine. Sixty-eight patients (42%) had anterior retroperitoneal midline exposure of the lumbar and lumbosacral spine. Total morbidity was 9.3% (7.4% for trauma patients and 1.8% for non trauma patients). Morbidity was highest in patients who had anterolateral exposure of the thoracic and lumbar spine (6.8%). Morbidity in patients who had midline exposure of L4 to S1 was 0%. Total mortality was 1.2% (3.3% for trauma patients and 0% for nontrauma patients). The acute care surgery service gained 3141 physician work relative value units (RVU) by performing those operations.

CONCLUSION

Anterior exposure of the thoracic and lumbar spine both for trauma and nontrauma related indications can be performed with acceptable morbidity and mortality by a dedicated acute care surgery service. Morbidity and mortality were higher in trauma patients and in those who underwent thoracolumbar procedures. Patients who had midline exposure of L4 to S1 for degenerative disc disease had the lowest morbidity.

LEVEL OF EVIDENCE

4.

Indications for anterior lumbar interbody fusion

Anterior lumbar interbody fusion (ALIF) has become a widely recognized surgical technique for degenerative pathology of the lumbar spine. Spinal fusion has evolved dramatically ever since the first successful internal fixation by Hadra in 1891 who used a posterior approach to wire adjacent cervical vertebrae in the treatment of fracture-dislocation. Advancements were made to reduce morbidity including bone grafting substitutes, metallic hardware instrumentation and improved surgical technique. The controversy regarding which surgical approach is best for treating various pathologies of the lumbar spine still exists. Despite being an established treatment modality, current indications of ALIF are yet to be clearly defined in the literature. This article discusses the current literature on indications on ALIF surgery.

Preoperative phlebography in anterior L4-L5 disc approach. Clinical experience about 63 cases

INTRODUCTION

The anterior approach of the L4-L5 disc requires a perfect knowledge of the venous anatomy. Some configurations make this approach hazardous. The purpose of this study is to classify configurations of the iliocava junction and the iliolumbar vein relative to L4-L5 and to analyze vascular complications.

MATERIALS AND METHODS

The preoperative phlebographies of 63 patients (30 men, 33 women, mean age 42years) undergoing a L4-L5 disc replacement were reviewed. The height of the iliocava junction was calculated as a ratio of the distance between the discs L4-L5 and L5-S1. The position of the left iliac vein was classified into three thirds across the width of L5. The number of branches of the iliolumbar vein was noted. Surgical reports were reviewed for complications.

RESULTS

The height of the iliocava junction was very high in six, high in 25, low in 26 and very low in six patients. The position of the left iliac vein was medial in 20, intermediate in 28 and lateral in 15 patients. The iliolumbar vein had one branch in 37, two in 20, three in three patients. It was not visualized in three cases. Variants of the venous anatomy included eight duplications of the left iliac vein, four wide diameters and one iliolumbar vein network pattern. Intraoperatively, three lacerations of iliolumbar veins occurred.

CONCLUSION

The iliocava anatomy is very variable: the safety of an anterior approach to the L4-L5 disc depends on it. The information of preoperative phlebography can help to plan a more accessible antero-lateral approach or to switch on a posterior fusion if the anatomical situation is deemed too dangerous, such as duplicated left iliac veins.

LEVEL OF EVIDENCE

Level IV. Diagnostic study.

Lumbar interbody fusion: a parametric investigation of a novel cage design with and without posterior instrumentation

INTRODUCTION

A finite element model of the L4-L5 human segment was employed to carry out a parametric biomechanical investigation of lumbar interbody fusion with a novel "sandwich" cage having an inner stiff core and two softer layers in the areas close to the endplates, with and without posterior fixation.

METHODS

Considered cage designs included: (a) cage in a homogeneous material with variable elastic modulus (19-2,000 MPa), (b) "sandwich" cage having an inner core (E=2,000 MPa) and softer layers (E=19 MPa) with variable thickness (1-2.5 mm). The latter cage was also considered in combination with posterior rods made with a material having variable elastic modulus (19-210,000 MPa). All the models were loaded with 500 N compression and moments of 7.5 Nm in flexion, extension, lateral bending and axial rotation.

RESULTS

The homogeneous cage stabilized the segment in flexion, lateral bending and axial rotation; in extension there was a destabilization up to 60% and remarkable cage movement (1 mm). The "sandwich" cage limited this phenomenon (cage movement<0.6 mm), effectively stabilized the segment in the other directions and lowered the maximal contact pressure on the endplates, reducing the risk of subsidence. Posterior fixation reduced spinal flexibility and cage movement.

CONCLUSIONS

The soft layers of the "sandwich" cage had the potential to limit the risk of cage subsidence and to preserve a significant loading of the structure even in combination with flexible posterior instrumentation, which may have a beneficial effect in promoting bony fusion.

Safe working zones using the minimally invasive lateral retroperitoneal transpsoas approach: a morphometric study

PURPOSE

The minimally invasive lateral retroperitoneal transpsoas approach is a recent technique developed for lumbar interbody fusion and discectomy. The proximity of the retroperitoneal vessels and ventral nerve roots to the surgical pathway increases the risk of injury to these anatomical structures. A precise knowledge of the regional anatomy of the lumbar plexus is required for safe passage through the psoas muscle. Preoperative examination of the axial MRI images will allow the surgeon to observe the neural structures at the operative levels and confirm that abdominal vessels do not obstruct the lateral disc space. The objective of this study was to determine the anatomic position of the ventral nerve roots and the retroperitoneal vessels in relation to the vertebral body in the degenerative spine and to delineate a safe working zone using magnetic resonance imaging (MRI).

METHODS

We retrospectively evaluated lumbar spine MRI in 78 patients (from L1-L2 to L4-L5). The total number of lumbar vertebrae measured was 304 levels. Sagittal MRI sections were used to measure disc height (anterior, middle, posterior). Axial MRI sections were used to measure the sagittal and transversal vertebral endplate diameters, the overlap between ventral nerve roots and the posterior border of the lower endplate of the vertebral body, and the overlap between the retroperitoneal vessels and the anterior border of the lower endplate of the vertebral body. The safe zone was subsequently calculated. It was defined as the relative lower endplate vertebral body sagittal diameter that is anterior to the nerve root and is posterior to the retroperitoneal vessels.

RESULTS

The safe working zone was 75.3% of the lower endplate of the vertebral body sagittal diameter at L1-L2, 59.5% at L2-L3, 51.9% at L3-L4 and 37.8% at L4-L5 levels. This area significantly decreases from L1-L2 to L4-L5 (p < 0.05). Compared with L1-L2, L2-L3 levels, the more anterior position of the nerve root and the more posterior position of the retroperitoneal vessels at the L4-L5 level causes a significant reduction of this area. Compared with the L3-L4 level, we observed that the safe zone decrease was simply secondary to the more anterior position of the nerve roots at the L4-L5 level.

CONCLUSION

Preoperative planning and safe zone delineation are a simple method to assess the relative position of neural and vascular anatomic structures in relation to the surgical area. This method can help spine surgeons to prevent perioperative complications.

Autogenous bone marrow stromal cell sheets-loaded mPCL/TCP scaffolds induced osteogenesis in a porcine model of spinal interbody fusion

This study was designed to investigate whether a tissue-engineered construct composed of autogenous cell sheets and a polycaprolactone-based bioresorbable scaffold would enhance bone regeneration and spinal interbody fusion in a large animal model. Porcine-derived autogenous bone marrow stromal cells (BMSCs) cultured into multilayered cell sheets were induced into osteogenic differentiation with dexamethasone, l-ascorbic acid, and β-glycerol phosphate. These cell sheets were assembled with bioresorbable scaffolds made from medical-grade poly(epsilon-caprolactone) incorporating 20% β-tricalcium phosphate (mPCL/TCP) as tissue-engineered BMSC constructs. L2/3, L4/5 discectomies and decortication of the vertebral end plates were performed on 16 SPF Yorkshire pigs through an anterolateral approach. The tissue-engineered BMSC constructs were transplanted into the prepared intervertebral disc spaces of half of the pigs (n = 8), whereas cell-free mPCL/TCP served as controls in the remaining pigs. New bone formation and spinal fusion were evaluated at 3 and 6 months using microcomputed tomography, histology, fluorochrome bone labeling, and biomechanical testing. New bone formation was evident as early as 3 months in the BMSC group. At 6 months, bony fusion was observed in >60% (5/8) of segments in the BMSC group. None of the control animals with cell-free scaffold showed fusion at both time points. Biomechanical evaluation further revealed a significantly increased segmental stability in the BMSC group compared with the cell-free group at 6 months postimplantation (p < 0.01). These findings suggest that mPCL/TCP scaffolds loaded with in vitro differentiated autogenous BMSC sheets could induce bone formation and interbody fusion. This in turn resulted in enhanced segmental stability of the lumbar spine.

Implications of lumbar plexus anatomy for removal of total disc replacements through a posterior approach

STUDY DESIGN

An anatomic study in which the lumbar plexuses of 14 embalmed cadavers were dissected bilaterally and measured using a posterior approach.

OBJECTIVE

To determine the cephalocaudal (root-to-root) distances and the mediolateral (root-to-tether) distances within the lumbar plexus and determine the feasibility for removal of a lumbar total disc replacement (TDR) through these anatomic spaces using a posterior approach.

SUMMARY OF BACKGROUND DATA

Currently, lumbar TDRs are implanted primarily through an anterior retroperitoneal or transperitoneal approach. However, revision surgeries through these approaches can be complicated by significant adhesions, with potential injuries to intra- and retroperitoneal contents. Advancements in accessing anterior column structures through a posterior lumbar extracavitary approach suggest that posterior removal of TDRs may be an alternative. Unlike the thoracic extracavitary approach in which ligation of the thoracic nerve rarely leaves significant morbidity, the lumbar extracavitary approach cannot rely on the analogous ligation of the lumbar root to achieve access. Therefore, feasibility of the lumbar extracavitary approach depends on the presence of sufficient anatomic space between the tethered nerves of the lumbar plexus.

METHODS

Fourteen adult cadavers (5 M/9F) were dissected through a posterior approach to expose the lumbar plexus bilaterally. The root-to-root distances at levels L2-S1 and corresponding root-to-tether distances at levels L3-L5 were measured bilaterally.

RESULTS

Root-to-root distance was smallest at the male L5-S1 interval (11.7 +/- standard deviations 4.1 mm). Root-to-tether distance was smallest at the female L5 (43.1 +/- standard deviations 8.4 mm). These plexus measurements compare favorably with the CHARITE TDR components, in which the thickest sliding core is 11.0 mm in height and the largest endplate is 42.0 mm in width.

CONCLUSION

This anatomic study suggests that posterior TDR removal is possible in the lumbar spine without undue risk to the surrounding nervous structures.