Does Implant Density Impact Three-Dimensional Deformity Correction in Adolescent Idiopathic Scoliosis with Lenke 1 and 2 Curves Treated by Posterior Spinal Fusion without Ponte Osteotomies?

STUDY DESIGN: Retrospective cohort study. PURPOSE: To determine whether implant density impact three-dimensional deformity correction in posterior spinal fusion (PSF) without Ponte osteotomies (POs) for patients with Lenke 1 and 2 adolescent idiopathic scoliosis (AIS). OVERVIEW OF LITERATURE: Currently, the optimal pedicle screw (PS) density for flexible moderate-sized thoracic AIS curve correction is still controversial. There are limited data regarding the impact of implant density on three-dimensional correction in PSF without the use of PO for thoracic AIS surgery. METHODS: A database of patients with AIS with Lenke 1 and 2 curves treated with PSF without PO and instrumented with PSs and ≥2-year follow-up was reviewed. The preoperative, immediate, and final follow-up postoperative radiographs were analyzed. The correlation between PS density and the following factors were determined: major curve correction (MCC), correction index (CI; MCC/curve flexibility), kyphosis angle change, and rib index (RI) correction. Then, patients were divided into low-density (LD) and high-density (HD) groups according to mean PS density for the entire cohort (1.5 PS per level). Demographics and radiographic and clinical outcomes were compared between groups. RESULTS: The study included 99 patients with Lenke 1 and 23 patients with Lenke 2 AIS. The average MCC was 67.2%. There was no correlation between screw density and these parameters: MCC (r=0.10, p=0.26), CI (r=0.16, p=0.07), change in T2-T12 kyphosis angle (r=-0.13, p=0.14), and RI correction (r=-0.09, p=0.37). Demographic and preoperative radiographic parameters were similar between the LD and HD groups. At the latest follow-up, there were no differences between the two groups in regard to MCC, CI, change in T2-T12 kyphosis angle, RI correction, and Scoliosis Research Society-30 scores (all p>0.05). CONCLUSIONS: This study revealed no significant correlation between screw density and curve correction in any planes. HD construct may not provide better deformity correction in patients with flexible and moderate thoracic AIS undergoing PSF without PO.

Nuances of oblique lumbar interbody fusion at L5-S1: Three case reports.

BACKGROUND: Oblique lumbar interbody fusion is a mini-open retroperitoneal approach that uses a wide corridor between the left psoas muscle and the aorta above L5. This approach avoids the limitations of lateral lumbar interbody fusion, is considered less invasive than anterior lumbar interbody fusion, and is similarly effective for indirect decompression and improving lordosis while maintaining a low complication profile. Including L5-S1, when required, adds to these advantages, as this allows single-position surgery. However, variations in vascular anatomy can affect the ease of access to the L5-S1 disc. The nuances of three different oblique anterolateral techniques to access L5-S1 for interbody fusion, namely, left-sided intra-bifurcation, left-sided pre-psoas, and right-sided pre-psoas approaches, are illustrated using three representative case studies. CASE SUMMARY: Cases of three patients who underwent multilevel oblique lumbar interbody fusion including L5-S1, using one of the three different techniques, are described. All patients presented with symptomatic degenerative lumbar pathology and failed conservative management prior to surgery. The anatomical considerations that affected the decisions to utilize each approach are discussed. The pros and cons of each approach are also discussed. A parasagittal facet line objectively assesses the relationship between the left common iliac vein and the L5-S1 disc and assists in choosing the approach to L5-S1. CONCLUSION: Oblique retroperitoneal access to L5-S1 in the lateral decubitus position is possible through three different approaches. The choice of approach to L5-S1 may be individualized based on a patient's vascular anatomy using preoperative imaging. While most surgeons will rely on their experience and comfort level in choosing the approach, this article elucidates the nuances of each technique.

Superior Patellar Dislocation Reduced by Intra-articular Injection: A Case Report and Review of Literature.

CASE: A 53-year-old woman presented with a locked knee after an atraumatic hyperextension episode. Imaging showed an anterior tilt of the patella hinging over the superior trochlear margin, consistent with a superior patellar dislocation. The patella spontaneously reduced on an intra-articular injection with 15 mL of lidocaine in normal saline, after which she was able to actively range her knee. CONCLUSION: Superior patellar dislocations are rare and usually result from a sudden forced contraction of the quadriceps, trapping the patella over superior trochlear osteophytes. Reduction is possible through an intra-articular local anesthetic injection, without manipulation of the patella.

Long-term experience with simultaneous prone video-assisted thoracoscopic anterior spinal release and posterior spinal fusion in severe rigid pediatric spinal deformities.

PURPOSE: While posterior-alone techniques have been successful for most pediatric spinal deformities, anterior spinal release may be useful for severe rigid deformities. Traditional lateral-positioned video-assisted thoracoscopic surgical release (VATSR) followed by prone posterior spinal fusion (PSF) has been criticized for adding extensive operative morbidity. We aimed to reduce its disadvantages by performing prone VATSR and PSF simultaneously and evaluate its long-term outcomes. METHODS: All consecutive patients from 1991 to 2012 undergoing VATSR and PSF at one institution were retrospectively reviewed. The inclusion criteria comprised severe rigid thoracic scoliosis (> 70°, bending correction > 45°) or kyphosis (> 75°, bolster correction > 45°), and a minimum 2 year follow-up. Demographics, operative data, hospital stay, and radiographic correction data were compared between patients who had undergone sequential VATSR followed by PSF and those who had undergone these procedures simultaneously. RESULTS: Of 153 patients who had undergone VATSR and PSF, 53 met the inclusion criteria (31 sequential, 22 simultaneous; average follow-up, 50 [range, 24-86] months). Age, preoperative measurements and flexibility, and perioperative complications did not differ significantly. The simultaneous group showed significantly lower operative time (449 vs. 618 min), blood loss (1039 vs. 1906 cc), and hospital stay (6.3 vs. 8.5 days) (all, p < 0.05). Postoperative radiographic correction and maintenance at the final follow-up showed a non-significant trend favoring the simultaneous group. CONCLUSION: Our simultaneous prone VATSR and PSF technique showed significantly lower operative time, blood loss, and hospital stay compared with the traditional sequential VATSR and PSF method, suggesting its value in treating rigid deformities.

Inclusion of L5-S1 in oblique lumbar interbody fusion-techniques and early complications-a single center experience.

BACKGROUND CONTEXT: The oblique prepsoas retroperitoneal approach to the lumbar spine for interbody fusion or oblique lumbar interbody fusion (OLIF) provides safe access to nearly all lumbar levels. A wide interval between the psoas and aorta allows for a safe and straightforward left-sided oblique approach to the discs above L5. Inclusion of L5-S1 in this approach, however, requires modifications in the technique to navigate the complex and variable vascular anatomy distal to the bifurcation of the great vessels. While different oblique approaches to L5-S1 have been described in the literature, to our knowledge, no previous study has provided guidance for the choice of technique. PURPOSE: Our objectives were to evaluate our early experience with the safety of including L5-S1 in OLIF using 3 different approach techniques, as well as to compare early complications between OLIF with and without L5-S1 inclusion. STUDY DESIGN: Retrospective cohort study. PATIENT SAMPLE: Of the 87 patients who underwent lumbar interbody fusion at 167 spinal levels via an OLIF approach, 19 included L5-S1 (group A) and 68 did not (group B). OUTCOME MEASURES: Demographics, levels fused, indications, operative time (ORT), estimated blood loss (EBL), vascular ligation, intraoperative blood transfusion, length of stay (LOS), discharge to rehabilitation facility, and complications (intraoperative, early ≤90 days, and delayed >90 days) were retrospectively assessed and compared between the groups. METHODS: A retrospective chart and imaging review of all consecutive patients who underwent OLIF at a single institution was performed. Indications for OLIF included symptomatic lumbar degenerative stenosis, deformity, and spondylolisthesis. The L5-S1 level, when included, was approached via one of the following 3 techniques: (1) a left-sided intrabifurcation approach; (2) left-sided prepsoas approach; and (3) right-sided prepsoas approach. Vascular anatomic variations at the lumbosacral junction were evaluated using the preoperative magnetic resonance imaging (MRI), and a "facet line" was proposed to assess this relationship. A minimum of 6 months of follow-up data were assessed for approach-related morbidities. RESULTS: Demographics and operative indications were similar between the groups. The mean follow-up was 10.8 (6-36) months. ORT was significantly longer in group A than in group B (322 vs. 256.3 min, respectively; p=.001); however, no difference in ORT between the two groups was found in the subanalyses for 2- and 3-level surgeries. Differences in EBL (260 vs. 207.91 cc, p=.251) and LOS (2.76 vs. 2.48 days, p=.491) did not reach statistical significance. Ligation of the iliolumbar vein, segmental veins, median sacral vessels, or any vascular structure, as needed for adequate exposure, was required in 13 (68.4%) patients from group A and 4 (5.9%) from group B (p<.00001). Two patients suffered minor vascular injuries (1 in each group); however, no major vascular injuries were seen. Complications were not significantly different between groups A and B, or between the three approaches to L5-S1, and trended lower in the latter part of the series as the learning curve progressed. CONCLUSIONS: Inclusion of L5-S1 in OLIF is safe and feasible through three different approaches but likely involves greater operative complexity. In our early experience, inclusion of L5-S1 showed no increase in early complications. This is the first series that reports the use of 3 different oblique approaches to L5-S1. The proposed "facet line" in the preoperative MRI may guide the choice of approach.

Oblique Lumbar Interbody Fusion in Patient with Persistent Left-Sided Inferior Vena Cava: Case Report and Review of Literature.

BACKGROUND: Oblique lumbar interbody fusion takes advantage of the wide interval between the aorta and left-sided psoas muscle to access the lumbar spine, allowing a minimally invasive approach for interbody fusion with lower associated morbidity. As this approach is gaining popularity among spine surgeons, it is important to understand the potential pitfalls that may arise in patients with congenital anomalies of the vascular anatomy. CASE DESCRIPTION: We present a case of a persistent left-sided inferior vena cava (IVC) affecting the side of approach in a patient undergoing lumbar interbody fusion through an oblique prepsoas retroperitoneal approach. Preoperative imaging of our patient revealed a persistent left-sided inferior vena cava with a wide interval between the aorta and the right-sided psoas, allowing us a right-sided oblique approach. CONCLUSIONS: Thorough preoperative imaging evaluation is essential to identify vascular anomalies that may hinder oblique prepsoas retroperitoneal approach to the lumbar spine. Although rare, double IVC or isolated left IVC may complicate the oblique approach.

Growing Rods Are an Effective Fusionless Method of Controlling Early-Onset Scoliosis Associated With Neurofibromatosis Type 1 (NF1): A Multicenter Retrospective Case Series.

BACKGROUND: Spinal deformities associated with neurofibromatosis type 1 (NF1) often have an early onset. These curves frequently develop dysplastic features. Rapid progression is common, and is often difficult to control with casting or bracing. Spinal fusion at a young age can potentially interfere with chest and trunk growth. Growing rods (GRs) have been used in early-onset scoliosis (EOS) effectively. The purpose of this study was to evaluate GR use in NF1. METHODS: Retrospective data collection was performed from a multicenter EOS database with additional patients from our own institute. Each patient had a genetic diagnosis of NF1 and was treated with GR. Results were compared with reported results of GR in EOS in the literature. RESULTS: Fourteen patients from 5 centers underwent a total of 71 procedures with an average follow-up of 54 months. Mean age at surgery was 6.8 years. Means of initial and final curves were 74 and 36 degrees, respectively (51% correction). Spine grew at an average of 39 mm (11.2 mm per year). Implant-related complications were the most common (8/14, 57%), including failure of proximal construct (5/14), rod breakage (2/14), and prominent implants (1/14). There was no significant difference between screws and hooks as proximal anchors (Fischer test). Two patients had deep infection that needed debridement. CONCLUSIONS: This retrospective pooled data study is the first report on the treatment of early-onset NF1 scoliosis with GRs. The use of GRs in these patients effectively controls the spinal deformity and facilitates growth of the spine. The complications were no greater than those seen in other conditions causing EOS. Failure of proximal anchors was found to be the most common complication. LEVEL OF EVIDENCE: Level IV-retrospective case series.

Occupant and Crash Characteristics of Elderly Subjects With Thoracic and Lumbar Spine Injuries After Motor Vehicle Collisions.

STUDY DESIGN: Retrospective study of a prospectively gathered database. OBJECTIVE: To investigate the incidence and pattern of thoracic and lumbar (T and L) spine injuries among elderly subjects involved in motor vehicle collision (MVC). SUMMARY OF BACKGROUND DATA: Adults age 65 and older currently constitute more than 16% of all licensed drivers. Despite driving less than the young, older drivers are involved in a higher proportion of crashes. Notwithstanding the safety features in modern vehicles, 15.8% to 51% of all T and L spine injuries result from MVCs. METHODS: Crash Injury Research and Engineering Network database is a prospectively maintained, multicentered database that enrolls MVC occupants with moderate-to-severe injuries. It was queried for T and L spine injuries in subjects 65 and older. 142 Crash Injury Research and Engineering Network files for all elderly individuals were reviewed for demographic, injury, and crash data. Each occupant's T and L injury was categorized using a modified Denis classification. RESULTS: Of 661 elderly subjects, 142 (21.48%) sustained T and L spine injuries. Of the 102 major injuries, there were 63 compression, 20 burst and 12 extension fractures. Seatbelt use predisposed elderly subjects to compression and burst fractures, whereas seatbelt and airbag use predisposed to burst fractures. Deployment of airbags without seatbelt use appeared to predispose elderly subjects to neurological injury, higher Injury Severity Score, and higher mortality. Occupants using 3-point belts who had airbags deployed during the collision had the lowest rates of fatality and neurological injury. CONCLUSION: T and L spine injuries in the elderly are not uncommon despite restraint use. Whereas seatbelts used alone and in conjunction with airbag deployment reduced fatalities and neurological injuries in the elderly, deployment of airbags in occupants without seatbelts predisposed to more severe injury.

Occupant and crash characteristics in thoracic and lumbar spine injuries resulting from motor vehicle collisions.

BACKGROUND CONTEXT: Motor vehicle collisions (MVC) are a leading cause of thoracic and lumbar (T and L) spine injuries. Mechanisms of injury in vehicular crashes that result in thoracic and lumbar fractures and the spectrum of injury in these occupants have not been extensively studied in the literature. PURPOSE: The objective was to investigate the patterns of T and L spine injuries after MVC; correlate these patterns with restraint use, crash characteristics, and demographic variables; and study the associations of these injuries with general injury morbidity and fatality. STUDY DESIGN/SETTING: The study design is a retrospective study of a prospectively gathered database. PATIENT SAMPLE: Six hundred thirty-one occupants with T and L (T1-L5) spine injuries from 4,572 occupants included in the Crash Injury Research and Engineering Network (CIREN) database between 1996 and 2011 were included in this study. OUTCOME MEASURES: No clinical outcome measures were evaluated in this study. METHODS: The CIREN database includes moderate to severely injured occupants from MVC involving vehicles manufactured recently. Demographic, injury, and crash data from each patient were analyzed for correlations between patterns of T and L spine injuries, associated extraspinal injuries and overall injury severity score (ISS), type and use of seat belts, and other crash characteristics. T and L spine injuries patterns were categorized using a modified Denis' classification to include extension injuries as a separate entity. RESULTS: T and L spine injuries were identified in 631 of 4,572 vehicle occupants, of whom 299 sustained major injuries (including 21 extension injuries) and 332 sustained minor injuries. Flexion-distraction injuries were more prevalent in children and young adults and extension injuries in older adults (mean age, 65.7 years). Occupants with extension injuries had a mean body mass index of 36.0 and a fatality rate of 23.8%, much higher than the fatality rate for the entire cohort (10.9%). The most frequent extraspinal injuries (Abbreviated Injury Scale Grade 2 or more) associated with T and L spine injuries involved the chest (seen in 65.6% of 631 occupants). In contrast to occupants with major T and L spine injuries, those with minor T and L spine injuries showed a strikingly greater association with pelvic and abdominal injuries. Occupants with minor T and L spine injuries had a higher mean ISS (27.1) than those with major T and L spine injuries (25.6). Among occupants wearing a three-point seat belt, 35.3% sustained T and L spine injuries, whereas only 11.6% of the unbelted occupants sustained T and L spine injuries. Three-point belted individuals were more likely to sustain burst fractures, whereas two-point belted occupants sustained flexion-distraction injuries most often and unbelted occupants had a predilection for fracture-dislocations of the T and L spines. Three-point seat belts were protective against neurologic injury, higher ISS, and fatality. CONCLUSIONS: T and L spine fracture patterns are influenced by the age of occupant and type and use of seat belts. Despite a reduction in overall injury severity and mortality, seat belt use is associated with an increased incidence of T and L spine fractures. Minor T and L spine fractures were associated with an increased likelihood of pelvic and abdominal injuries and higher ISSs, demonstrating their importance in predicting overall injury severity. Extension injuries occurred in older obese individuals and were associated with a high fatality rate. Future advancements in automobile safety engineering should address the need to reduce T and L spine injuries in belted occupants.

Single-level transforaminal interbody fusion for traumatic lumbosacral fracture-dislocation: a case report.

L5S1 fracture-dislocations are rare three-column injuries. The infrequency of this injury has led to a lack of a universally accepted treatment strategy. Transforaminal lumbar interbody fusion (TLIF) has been shown to be an effective approach for interbody fusion in degenerative indications, but has not been previously reported in the operative management of traumatic lumbosacral dislocation. The authors report a case of traumatic L5S1 fracture-dislocation in a 30-year-old male, presenting with a right-sided L5 neurologic deficit, following a street sweeper accident. Imaging revealed an L5S1 fracture-dislocation with fracture of the S1 body. Open reduction with TLIF and L5S1 posterolateral instrumented fusion was carried out within 24 hours of injury. Excellent reduction was obtained, and maintained at long-term follow-up, with complete resolution of pain and neurologic deficit. In this patient, L5S1 fracture-dislocation was treated successfully, with an excellent outcome, with a single level TLIF and instrumented posterolateral fusion at L5S1.