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

OBJECTIVE: In an effort to prevent loss of segmental lordosis (SL) with minimally invasive interbody fusions, manufacturers have increased the amount of lordosis that is built into interbody cages. However, the relationship between cage lordotic angle and actual SL achieved intraoperatively remains unclear. The purpose of this study was to determine if the lordotic angle manufactured into an interbody cage impacts the change in SL during minimally invasive surgery (MIS) for lumbar interbody fusion (LIF) done for degenerative pathology. METHODS: The authors performed a retrospective review of a single-surgeon database of adult patients who underwent primary LIF between April 2017 and December 2018. Procedures were performed for 1-2-level lumbar degenerative disease using contemporary MIS techniques, including transforaminal LIF (TLIF), lateral LIF (LLIF), and anterior LIF (ALIF). Surgical levels were classified on lateral radiographs based on the cage lordotic angle (6°-8°, 10°-12°, and 15°-20°) and the position of the cage in the disc space (anterior vs posterior). Change in SL was the primary outcome of interest. Subgroup analyses of the cage lordotic angle within each surgical approach were also conducted. RESULTS: A total of 116 surgical levels in 98 patients were included. Surgical approaches included TLIF (56.1%), LLIF (32.7%), and ALIF (11.2%). There were no differences in SL gained by cage lordotic angle (2.7° SL gain with 6°-8° cages, 1.6° with 10°-12° cages, and 3.4° with 15°-20° cages, p = 0.581). Subgroup analysis of LLIF showed increased SL with 15° cages only (p = 0.002). The change in SL was highest after ALIF (average increase 9.8° in SL vs 1.8° in TLIF vs 1.8° in LLIF, p < 0.001). Anterior position of the cage in the disc space was also associated with a significantly greater gain in SL (4.2° vs -0.3°, p = 0.001), and was the only factor independently correlated with SL gain (p = 0.016). CONCLUSIONS: Compared with cage lordotic angle, cage position and approach play larger roles in the generation of SL in 1-2-level MIS for lumbar degenerative disease.

Functional and radiological outcome of anterior retroperitoneal versus posterior transforaminal interbody fusion in the management of single-level lumbar degenerative disease.

OBJECTIVE: In this study the authors compared the anterior lumbar interbody fusion (ALIF) and posterior transforaminal lumbar interbody fusion (TLIF) techniques in a homogeneous group of patients affected by single-level L5-S1 degenerative disc disease (DDD) and postdiscectomy syndrome (PDS). The purpose of the study was to analyze perioperative, functional, and radiological data between the two techniques. METHODS: A retrospective analysis of patient data was performed between 2015 and 2018. Patients were clustered into two homogeneous groups (group 1 = ALIF, group 2 = TLIF) according to surgical procedure. A statistical analysis of clinical perioperative and radiological findings was performed to compare the two groups. A senior musculoskeletal radiologist retrospectively revised all radiological images. RESULTS: Seventy-two patients were comparable in terms of demographic features and surgical diagnosis and included in the study, involving 32 (44.4%) male and 40 (55.6%) female patients with an average age of 47.7 years. The mean follow-up duration was 49.7 months. Thirty-six patients (50%) were clustered in group 1, including 31 (86%) with DDD and 5 (14%) with PDS. Thirty-six patients (50%) were clustered in group 2, including 28 (78%) with DDD and 8 (22%) with PDS. A significant reduction in surgical time (107.4 vs 181.1 minutes) and blood loss (188.9 vs 387.1 ml) in group 1 (p < 0.0001) was observed. No significant differences in complications and reoperation rates between the two groups (p = 0.561) was observed. A significant improvement in functional outcome was observed in both groups (p < 0.001), but no significant difference between the two groups was found at the last follow-up. In group 1, a faster median time of return to work (2.4 vs 3.2 months) was recorded. A significant improvement in L5-S1 postoperative lordosis restoration was registered in the ALIF group (9.0 vs 5.0, p = 0.023). CONCLUSIONS: According to these results, interbody fusion is effective in the surgical management of discogenic pain. Even if clinical benefits were achieved earlier in the ALIF group (better scores and faster return to work), both procedures improved functional outcomes at last follow-up. The ALIF group showed significant reduction of blood loss, shorter surgical time, and better segmental lordosis restoration when compared to the TLIF group. No significant differences in postoperative complications were observed between the groups. Based on these results, the ALIF technique enhances radiological outcome improvement in spinopelvic parameters when compared to TLIF in the management of adult patients with L5-S1 DDD.

Correction of severe spinopelvic mismatch: decreased blood loss with lateral hyperlordotic interbody grafts as compared with pedicle subtraction osteotomy.

OBJECTIVE Pedicle subtraction osteotomy (PSO) provides extensive correction in patients with fixed sagittal plane imbalance but is associated with high estimated blood loss (EBL). Anterior column realignment (ACR) with lateral graft placement and sectioning of the anterior longitudinal ligament allows restoration of lumbar lordosis (LL). The authors compare peri- and postoperative measures in 2 groups of patients undergoing correction of a sagittal plane imbalance, either through PSO or the use of lateral lumbar fusion and ACR with hyperlordotic (20°-30°) interbody cages, with stabilization through standard posterior instrumentation in all cases. METHODS The authors performed a retrospective chart review of cases involving a lumbar PSO or lateral lumbar interbody fusion and ACR (LLIF-ACR) between 2010 and 2015 at the authors' institution. Patients who had a PSO in the setting of a preexisting fusion that spanned more than 4 levels were excluded. Demographic characteristics, spinopelvic parameters, EBL, operative time, and LOS were analyzed and compared between patients treated with PSO and those treated with LLIF-ACR. RESULTS The PSO group included 14 patients and the LLIF-ACR group included 13 patients. The mean follow-up was 13 months in the LLIF-ACR group and 26 months in the PSO group. The mean EBL was significantly lower in the LLIF-ACR group, measuring approximately 50% of the mean EBL in the PSO group (1466 vs 2910 ml, p < 0.01). Total LL correction was equivalent between the 2 groups (35° in the PSO group, 31° in the LLIF-ACR group, p > 0.05), as was the preoperative PI-LL mismatch (33° in each group, p > 0.05) and the postoperative PI-LL mismatch (< 1° in each group, p = 0.05). The fusion rate as assessed by the need for reoperation due to pseudarthrosis was lower in the LLIF-ACR group but not significantly so (3 revisions in the PSO group due to pseudarthrosis vs 0 in the LLIF-ACR group, p > 0.5). The total operative time and LOS were not significantly different in the 2 groups. CONCLUSIONS This is the first direct comparison of the LLIF-ACR technique with the PSO in adult spinal deformity correction. The study demonstrates that the LLIF-ACR provides equivalent deformity correction with significantly reduced blood loss in patients with a previously unfused spine compared with the PSO. This technique provides a powerful means to avoid PSO in selected patients who require spinal deformity correction.

A review of pediatric lumbar spine trauma.

Pediatric spine fractures constitute 1%-3% of all pediatric fractures. Anywhere from 20% to 60% of these fractures occur in the thoracic or lumbar spine, with the lumbar region being more affected in older children. Younger children tend to have a higher proportion of cervical injuries. The pediatric spine differs in many ways from the adult spine, which can lead to increased ligamentous injuries without bone fractures. The authors discuss and review pediatric lumbar trauma, specifically focusing on epidemiology, radiographic findings, types and mechanisms of lumbar spine injury, treatment, and outcomes.

Utilization of anterior lumbar interbody fusion for severe kyphotic deformity secondary to Pott's disease: illustrative case.

BACKGROUND: Spinal tuberculosis may result in severe kyphotic deformity. Effective restoration of lordosis and correction of sagittal balance often requires invasive osteotomies associated with significant morbidity. The advantages of focusing on symptomatic management and staging in the initial treatment of these deformities have not been well reported to date. OBSERVATIONS: The authors reported the case of a 64-year-old Vietnamese woman with a history of spinal tuberculosis who underwent anterior lumbar interbody fusion (ALIF) for symptomatic treatment of L5-S1 radiculopathy resulting from fixed kyphotic deformity. Postoperatively, the patient experienced near immediate symptom improvement, and radiographic evidence at 1-year follow-up showed continued lordotic correction of 30° as well as stable sagittal balance. LESSONS: In this case, an L5-S1 ALIF was sufficient to treat the patient's acute symptoms and provided satisfactory correction of a tuberculosis-associated fixed kyphotic deformity while effectively delaying more invasive measures, such as a vertebral column resection. Patients with adult spinal deformity may benefit from less invasive staging procedures before treating these deformities with larger surgeries.

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.

Radiographic findings for surgery-related complications after pedicle subtraction osteotomy for thoracolumbar kyphosis in 230 patients with ankylosing spondylitis.

OBJECTIVE: The purpose of this study was to investigate the rate of and the risk factors for surgery-related complications demonstrated on radiography after pedicle subtraction osteotomy (PSO) for thoracolumbar kyphosis in patients with ankylosing spondylitis (AS). METHODS: The authors retrospectively reviewed the medical records of 230 consecutive patients with thoracolumbar kyphosis due to AS who had undergone 1-level PSO at a single institution in the period from 2010 to 2017. The causes of surgery-related complications were divided into two types: surgical/technical failure and mechanical failure. RESULTS: The patients consisted of 20 women and 210 men, with an average age of 43.4 years. The average follow-up period was 39.0 months. The preoperative sagittal vertical axis was 18.5 ± 69.3 cm, which improved to 4.9 ± 4.6 cm after PSO. Of the 77 patients (33.5%) who experienced minor or major surgery-related complications, 56 had complications related to surgical/technical failure (overall incidence 24.3%) and 21 had complications related to mechanical failure (overall incidence 9.1%). Fourteen patients (6.1%) underwent reoperation. However, among the 77 patients with complications, the rate of revision surgery was 18.2%. The most common radiological complications were as follows: sagittal translation in 24 patients, coronal imbalance in 20, under-correction in 8, delayed union in 8, and distal junctional failure and kyphosis in 8. The most common causes of reoperation were coronal imbalance in 4 patients, symptomatic malposition of pedicle screws in 3, and distal junctional failure in 3. Delayed union was statistically correlated with posterior sagittal translation (p = 0.007). CONCLUSIONS: PSO can provide acceptable radiographic outcomes for the correction of thoracolumbar kyphosis in patients with AS. However, a high incidence of surgery-related complications related to mechanical failure and surgical technique can develop. Thorough radiographic investigation before and during surgery is needed to determine whether complete ossification occurs along the anterior and posterior longitudinal ligaments of the spine.

Comparative study of multilevel posterior interbody fusion plus anterior longitudinal ligament release versus classic multilevel posterior interbody fusion in the treatment of adult spinal deformities.

OBJECTIVE: Sagittal imbalance and loss of lumbar lordosis are the main drivers of functional disability in adult degenerative scoliosis. The main limitations of the classic posterior lumbar interbody fusion technique are increased risk of neurological injury and suboptimal correction of the segmental lordosis. Here, the authors describe the radiological results of a modified posterior lumbar interbody fusion and compare the results with a historical cohort of patients. METHODS: Eighty-two consecutive patients underwent surgical treatment for degenerative scoliosis/kyphosis in a single tertiary referral center for complex spinal surgery. Fifty-five patients were treated using the classic multilevel posterior lumbar interbody fusion (MPLIF) technique and 27 were treated using the modified MPLIF technique to include a release of the anterior longitudinal ligament (ALL) and the annulus. A radiographic review of both series of patients was performed by two independent observers. Functional outcomes were obtained, and patients were registered in the European Spine Tango registry. RESULTS: The mean L4-5 disc angle increased by 3.14° in the classic MPLIF group and by 12.83° in MPLIF plus ALL and annulus release group. The mean lumbar lordosis increased by 15.23° in the first group and by 25.17° in the second group. The L4-S1 lordosis increased on average by 4.92° in the classic MPLIF group and increased by a mean of 23.7° in the MPLIF plus ALL release group when both L4-5 and L5-S1 segments were addressed. There were significant improvements in the Core Outcome Measures Index and EQ-5D score in both groups (p < 0.001). There were no vascular or neurological injuries observed in either group. CONCLUSIONS: The authors' preliminary results suggest that more correction can be achieved at the disc level using posterior-based ALL and annulus release in conjunction with posterior lumbar interbody fusion. They demonstrate that ALL and annulus release can be performed safely using a posterior-only approach with minimal risk of vascular injury. However, the authors recommend that this approach should only be used by surgeons with considerable experience in anterior and posterior spinal surgery.

State of the union: a review of lumbar fusion indications and techniques for degenerative spine disease.

Lumbar fusion is an accepted and effective technique for the treatment of lumbar degenerative disease. The practice has evolved continually since Albee and Hibbs independently reported the first cases in 1913, and advancements in both technique and patient selection continue through the present day. Clinical and radiological indications for surgery have been tested in trials, and other diagnostic modalities have developed and been studied. Fusion practices have also advanced; instrumentation, surgical approaches, biologics, and more recently, operative planning, have undergone stark changes at a seemingly increasing pace over the last decade. As the general population ages, treatment of degenerative lumbar disease will become a more prevalent-and costlier-issue for surgeons as well as the healthcare system overall. This review will cover the evolution of indications and techniques for fusion in degenerative lumbar disease, with emphasis on the evidence for current practices.

The comprehensive anatomical spinal osteotomy and anterior column realignment classification.

OBJECTIVESpinal osteotomies and anterior column realignment (ACR) are procedures that allow preservation or restoration of spine lordosis. Variations of these techniques enable different degrees of segmental, regional, and global sagittal realignment. The authors propose a comprehensive anatomical classification system for ACR and its variants based on the level of technical complexity and invasiveness. This serves as a common language and platform to standardize clinical and radiographic outcomes for the utilization of ACR.METHODSThe proposed classification is based on 6 anatomical grades of ACR, including anterior longitudinal ligament (ALL) release, with varying degrees of posterior column release or osteotomies. Additionally, a surgical approach (anterior, lateral, or posterior) was added. Reliability of the classification was evaluated by an analysis of 16 clinical cases, rated twice by 14 different spine surgeons, and calculation of Fleiss kappa coefficients.RESULTSThe 6 grades of ACR are as follows: grade A, ALL release with hyperlordotic cage, intact posterior elements; grade 1 (ACR + Schwab grade 1), additional resection of the inferior facet and joint capsule; grade 2 (ACR + Schwab grade 2), additional resection of both superior and inferior facets, interspinous ligament, ligamentum flavum, lamina, and spinous process; grade 3 (ACR + Schwab grade 3), additional adjacent-level 3-column osteotomy including pedicle subtraction osteotomy; grade 4 (ACR + Schwab grade 4), 2-level distal 3-column osteotomy including pedicle subtraction osteotomy and disc space resection; and grade 5 (ACR + Schwab grade 5), complete or partial removal of a vertebral body and both adjacent discs with or without posterior element resection. Intraobserver and interobserver reliability were 97% and 98%, respectively, across the 14-reviewer cohort.CONCLUSIONSThe proposed anatomical realignment classification provides a consistent description of the various posterior and anterior column release/osteotomies. This reliability study confirmed that the classification is consistent and reproducible across a diverse group of spine surgeons.

Risk factors for anterior bone loss in cervical disc arthroplasty.

OBJECTIVE The objective of this study was to identify the risk factors of anterior bone loss (ABL) in cervical disc arthroplasty (CDA) and the subsequent effect of this phenomenon. METHODS The authors performed a retrospective radiological review of 185 patients with a minimum 5-year follow-up after CDA (using Bryan, Discocerv, Mobi-C, or Baguera C). Postoperative radiographs were examined and compared to the initial postoperative films to determine the percentage of ABL. The relationship of ABL to potential risk factors was analyzed. RESULTS Complete radiological assessment was available in 145 patients with 193 CDRs and 383 endplates (average age 45 years, range 25-65 years, 54% women). ABL was identified in 63.7% of CDRs (48.7% mild, 11.9% moderate, 3.1% severe). Age (p = 0.770), sex (p = 0.200), postoperative alignment (p = 0.330), midflexion point (p = 0.509), maximal flexion (p = 0.080), and extension (p = 0.717) did not relate to ABL. There was no significant difference in the rate of severe ABL between implants. Multilevel surgery conferred an increased risk of any and severe ABL (p = 0.013 for both). The upper endplate, defined as superior to the CDA, was more commonly involved (p = 0.008), but there was no significant difference whether the endplate was between or not between implants (p = 0.226). The development of ABL did not affect the long-term range of movement (ROM) of the CDA, but did increase the overall risk of autofusion. ABL was not associated with pain or functional deficits. No patients required a reoperation or revision of their implant during the course of this study, and there were no cases of progressive ABL beyond the first year. CONCLUSIONS ABL is common in all implant types assessed, although most is mild. Age, sex, postoperative alignment, ROM, and midflexion point do not relate to this phenomenon. However, the greater the number of levels operated, the higher the risk of developing ABL. The development of ABL has no long-term effect on the mechanical functioning of the disc or necessity for revision surgery, although it may increase the rate of autofusion.

Effects of intradiscal vacuum phenomenon on surgical outcome of lateral interbody fusion for degenerative lumbar disease.

OBJECTIVE The authors investigated whether the presence of intradiscal vacuum phenomenon (IVP) results in greater correction of disc height and restoration of segmental lordosis (SL). METHODS A retrospective chart review was performed on every patient at the University of South Florida's Department of Neurosurgery treated with lateral lumbar interbody fusion between 2011 and 2015. From these charts, preoperative plain radiographs and CT images were reviewed for the presence of IVP. Preoperative and postoperative posterior disc height (PDH), anterior disc height (ADH), and SL were measured at disc levels with IVP and compared with those at disc levels without IVP using the t-test. Linear regression was used to evaluate the factors that predict changes in PDH, ADH, and SL. RESULTS One hundred forty patients with 247 disc levels between L-1 and L-5 were treated with lateral lumbar interbody fusion. Among all disc levels treated, the mean PDH increased from 3.69 to 6.66 mm (p = 0.011), the mean ADH increased from 5.45 to 11.53 mm (p < 0.001), and the mean SL increased from 9.59° to 14.55° (p < 0.001). Significantly increased PDH was associated with the presence of IVP, addition of pedicle screws, and lack of cage subsidence; significantly increased ADH was associated with the presence of IVP, anterior longitudinal ligament (ALL) release, addition of pedicle screws, and lack of subsidence; and significantly increased SL was associated with the presence of IVP and ALL release. CONCLUSIONS IVP in patients with degenerative spinal disease remains grossly underreported. The data from the present study suggest that the presence of IVP results in increased restoration of disc height and SL.

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

OBJECTIVE The authors' aim in this study was to evaluate whether sagittal plane correction can be obtained from the front by overpowering previous posterior instrumentation and/or fusion with hyperlordotic anterior lumbar interbody fusion (ALIF) cages in patients undergoing revision surgery for degenerative spinal conditions and/or spinal deformities. METHODS The authors report their experience with the application of hyperlordotic cages at 36 lumbar levels for ALIFs in a series of 20 patients who underwent revision spinal surgery at a single institution. Included patients underwent staged front-back procedures: ALIFs with hyperlordotic cages (12°, 20°, and 30°) followed by removal of posterior instrumentation and reinstrumentation from the back. Patients were divided into the following 2 groups depending on the extent of posterior instrumentation and fusion during the second stage: long constructs (≥ 6 levels with extension into thoracic spine and/or pelvis) and short constructs (< 6 levels). Preoperative and postoperative standing radiographs were evaluated to measure segmental lordosis (SL) along with standard sagittal parameters. Radiographic signs of pseudarthrosis at previously fused levels were also sought in all patients. RESULTS The average patient age was 54 years (range 30-66 years). The mean follow-up was 11.5 months (range 5-26 months). The mean SL achieved with 12°, 20°, and 30° cages was 13.1°, 19°, and 22.4°, respectively. The increase in postoperative SL at the respective surgically treated levels for 12°, 20°, and 30° cages that were used to overpower posterior instrumentation/fusion averaged 6.1° (p < 0.05), 12.5° (p < 0.05), and 17.7° (p < 0.05), respectively. No statistically significant difference was found in SL correction at levels in patients who had pseudarthrosis (n = 18) versus those who did not (n = 18). The mean overall lumbar lordosis increased from 44.3° to 59.8° (p < 0.05). In the long-construct group, the mean improvement in sagittal vertical axis was 85.5 mm (range 19-249.3 mm, p < 0.05). Endplate impaction/collapse was noted in 3 of 36 levels (8.3%). The anterior complication rate was 13.3%. No neurological complications or vascular injuries were observed. CONCLUSIONS ALIF in which hyperlordotic cages are used to overpower posterior spinal instrumentation and fusion can be expected to produce an increase in SL of a magnitude that is roughly half of the in-built cage lordotic angle. This technique may be particularly suited for lordosis correction from the front at lumbar levels that have pseudarthrosis from the previous posterior spinal fusion. Meticulous selection of levels for ALIF is crucial for safely and effectively performing this technique.

Posterior convex release and interbody fusion for thoracic scoliosis: technical note.

Anterior release and fusion is sometimes required in pediatric patients with thoracic scoliosis. Typically, a formal anterior approach is performed through open thoracotomy or video-assisted thoracoscopic surgery. The authors recently developed a technique for anterior release and fusion in thoracic scoliosis referred to as "posterior convex release and interbody fusion" (PCRIF). This technique is performed via the posterior-only approach typically used for posterior instrumentation and fusion and thus avoids a formal anterior approach. In this article the authors describe the technique and its use in 9 patients-to prevent a crankshaft phenomenon in 3 patients and to optimize the correction in 6 patients with a severe thoracic curve showing poor reducibility. After Ponte osteotomies at the levels requiring anterior release and fusion, intervertebral discs are approached from the convex side of the scoliosis. The annulus on the convex side of the scoliosis is incised from the lateral border of the pedicle to the lateral annulus while visualizing and protecting the pleura and spinal cord. The annulus in contact with the pleura and the anterior longitudinal ligament are removed before completing the discectomies and preparing the endplates. The PCRIF was performed at 3 levels in 4 patients and at 4 levels in 5 patients. Mean correction of the main thoracic curve, blood loss, and length of stay were 74.9%, 1290 ml, and 7.6 days, respectively. No neurological deficit, implant failure, or pseudarthrosis was observed at the last follow-up. Two patients had pleural effusion postoperatively, with 1 of them requiring placement of a chest tube. One patient had pulmonary edema secondary to fluid overload, while another patient underwent reoperation for a deep wound infection 3 weeks after the initial surgery. The technique is primarily indicated in skeletally immature patients with open triradiate cartilage and/or severe scoliosis. It can be particularly useful if there is significant vertebral rotation because access to the disc and anterior longitudinal ligament from the convex side will become safer. The PCRIF is an alternative to the formal anterior approach and does not require repositioning between the anterior and posterior stages, which prolongs the surgery and can be associated with an increased complication rate. The procedure can be done in the presence of preexisting pulmonary morbidity such as pleural adhesions and decreased pulmonary function because it does not require mobilization of the lung or single-lung ventilation. However, PCRIF can still be associated with pulmonary complications such as a pleural effusion, and care should be taken to avoid iatrogenic injury to the pleura. Placement of a deep wound drain at the level of the PCRIF is strongly recommended if postoperative bleeding is anticipated, to decrease the risk of pleural effusion.

Retropharyngeal abscess with secondary osteomyelitis and epidural abscess: proposed pathophysiological mechanism of an underrecognized complication of unstable craniocervical injuries: case report.

Because of the proximity of the oropharynx (a naturally contaminated region) to the spinal structures of the craniocervical junction, it is possible that small mucosal lacerations in the oropharynx caused by unstable traumatic craniocervical injuries may become contaminated and lead to secondary infection and osteomyelitis. In this report, the authors describe the case of a previously healthy and immunocompetent patient who developed a large retropharyngeal abscess with spinal osteomyelitis after a high-energy craniocervical injury. This unusual report of osteomyelitis with a delayed presentation after a high-energy traumatic injury of the craniocervical junction highlights the possibility of direct injury to a specific area in the oropharyngeal mucosa adjacent to the osteoligamentous structures of the craniocervical junction, an overall underrecognized complication of unstable craniocervical injuries.

Anterior hyperlordotic cages: early experience and radiographic results.

OBJECTIVE The aim of this study was to evaluate the segmental correction obtained from 20° and 30° hyperlordotic cages (HLCs) used for anterior lumbar interbody fusion in staged anterior and posterior fusion in adults with degenerative spinal pathology and/or spinal deformities. METHODS The authors report a retrospective case series of 69 HLCs in 41 patients with adult degenerative spine disease and/or deformities who underwent staged anterior, followed by posterior, instrumentation and fusion. There were 29 females and 12 males with a mean age of 55 years (range 23-76 years). The average follow-up was 10 months (range 2-28 months). Radiographic measurements of segmental lordosis and standard sagittal parameters were obtained on pre- and postoperative radiographs. Implant subsidence was measured at the final postoperative follow-up. RESULTS For 30° HLCs, the mean segmental lordosis achieved was 29° (range 26°-34°), but in the presence of spondylolisthesis this was reduced to 19° (range 12°-21°) (p < 0.01). For 20° HLCs, the mean segmental lordosis achieved was 19° (range 16°-22°). The overall mean lumbar lordosis increased from 39° to 59° (p < 0.01). The mean sagittal vertical axis (SVA) reduced from 113 mm (range 38-320 mm) to 43 mm (range -13 to 112 mm). Six cages (9%) displayed a loss of segmental lordosis during follow-up. The mean loss of segmental lordosis was 4.5° (range 3°-10°). A total complication rate of 20% with a 4.1% transient neurological complication rate was observed. The mean blood loss per patient was 240 ml (range 50-900 ml). CONCLUSIONS HLCs provide a reliable and stable degree of segmental lordosis correction. A 30° HLC will produce correction of a similar magnitude to a pedicle subtraction osteotomy, but with a lower complication rate and less blood loss.

First report of major vascular injury due to lateral transpsoas approach leading to fatality.

Extreme lateral interbody fusion (XLIF) has gained popularity among spine surgeons for treating multiple conditions of the lumbar spine. In contrast to the anterior lumbar interbody fusion (ALIF) approach, the minimally invasive XLIF approach affords wide access to the lumbar disc space without an access surgeon and causes minimal tissue disruption. The XLIF approach offers many advantages over other lumbar spine approaches, with a reportedly low complication profile. The authors describe the first fatality reported in the literature following an XLIF approach. They describe the case of a 50-year-old woman who suffered a fatal intraoperative injury to the great vessels during a lateral transpsoas approach to the L4-5 disc space.