Iliac Accessory Rod Technique for Rod Fracture Prevention in Long Fusion Constructs: 2-Dimensional Operative Video.

Implant-related complications in surgery for adult spinal deformity (ASD) account for roughly $1 billion US health care expenditures over 5 years, with a majority due to primary rod fracture.1,2 Traditional two-rod constructs have demonstrated rod fracture rates of up to 40%, with a median time to fracture of 3 years.3 Current supplementary rod techniques for decreasing rod fractures inadequately address the issue of increased strain across the lumbosacral junction.4 Here, we describe a novel four-rod technique using "iliac accessory rods," designed to mitigate rod fractures by reinforcing osteotomy levels and dispersing biomechanical stress across the lumbosacral junction. Compared with other supplementary rod techniques for ASD, iliac accessory rods anchor to independent iliac bolts.5 The added fixation points across the lumbosacral junction (4 iliac bolts total) substantially offloads stress on primary rods, most of which fracture near the lumbosacral junction.3 Additionally, connecting these rods to primary rods rostrally via side-to-side connectors, above the osteotomy levels, ensures mobile osteotomy segments are reinforced. Presented is a 78-year-old woman with ASD and worsening lower back pain, radiculopathy, and bilateral leg weakness who failed nonoperative management. She underwent T9 to bi-iliac instrumented fusion with L1-S1 posterior column osteotomies, L4-S1 transforaminal lumbar interbody fusions, and bilateral iliac accessory rod fixation. Postoperatively, she recovered well and had improvement in her symptoms. Imaging revealed correction of spinal alignment. The patient consented to the procedure, and the participants and any identifiable individuals consented to publication of his/her image. Institutional Review Board approval was waived because of institutional exemption policy.

Opioid Use Prior to Adult Spine Deformity Correction Surgery is Associated With Worse Pre- and Postoperative Back Pain and Prolonged Opioid Demands.

STUDY DESIGN: Prospective multicenter database post-hoc analysis. OBJECTIVES: Opioids are frequently prescribed for painful spinal conditions to provide pain relief and to allow for functional improvement, both before and after spine surgery. Amidst a current opioid epidemic, it is important for providers to understand the impact of opioid use and its relationship with patient-reported outcomes. The purpose of this study was to evaluate pre-/postoperative opioid consumption surrounding ASD and assess patient-reported pain outcomes in older patients undergoing surgery for spinal deformity. METHODS: Patients ≥60 years of age from 12 international centers undergoing spinal fusion of at least 5 levels and a minimum 2-year follow-up were included. Patient-reported outcome scores were collected using the Numeric Rating Scale for back and leg pain (NRS-B; NRS-L) at baseline and at 2 years following surgery. Opioid use, defined based on a specific question on case report forms and question 11 from the SRS-22r questionnaire, was assessed at baseline and at 2-year follow-up. RESULT: Of the 219 patients who met inclusion criteria, 179 (81.7%) had 2-year data on opioid use. The percentages of patients reporting opioid use at baseline (n = 75, 34.2%) and 2 years after surgery (n = 55, 30.7%) were similar (P = .23). However, at last follow-up 39% of baseline opioid users (Opi) were no longer taking opioids, while 14% of initial non-users (No-Opi) reported opioid use. Regional pre- and postoperative opioid use was 5.8% and 7.7% in the Asian population, 58.3% and 53.1% in the European, and 50.5% and 40.2% in North American patients, respectively. Baseline opioid users reported more preoperative back pain than the No-Opi group (7.0 vs 5.7, P = .001), while NRS-Leg pain scores were comparable (4.8 vs 4, P = .159). Similarly, at last follow-up, patients in the Opi group had greater NRS-B scores than Non-Opi patients (3.2 vs 2.3, P = .012), but no differences in NRS-Leg pain scores (2.2 vs 2.4, P = .632) were observed. CONCLUSIONS: In this study, almost one-third of surgical ASD patients were consuming opioids both pre- and postoperatively world-wide. There were marked international variations, with patients from Asia having a much lower usage rate, suggesting a cultural influence. Despite both opioid users and nonusers benefitting from surgery, preoperative opioid use was strongly associated with significantly more back pain at baseline that persisted at 2-year follow up, as well as persistent postoperative opioid needs.

A Novel Weave Tether Technique for Proximal Junctional Kyphosis Prevention in 71 Adult Spinal Deformity Patients: A Preliminary Case Series Assessing Early Complications and Efficacy.

BACKGROUND: Proximal junctional kyphosis (PJK) rates may be as high as 69.4% after adult spinal deformity (ASD) surgery. PJK is one of the greatest unsolved challenges in long-segment fusions for ASD and remains a common indication for costly and impactful revision surgery. Junctional tethers may help to reduce the occurrence of PJK by attenuating adjacent-segment stress. OBJECTIVE: To report our experience and assess early safety associated with a novel "weave-tether technique" (WTT) for PJK prophylaxis in a large series of patients. METHODS: This single-center retrospective study evaluated consecutive patients who underwent ASD surgery including WTT between 2017 and 2018. Patient demographics, operative details, standard radiographic measurements, and complications were analyzed. RESULTS: A total of 71 patients (mean age 66 ± 12 yr, 65% women) were identified. WTT included application to the upper-most instrumented vertebrae (UIV) + 1 and UIV + 2 in 38(53.5%) and 33(46.5%) patients, respectively. No complications directly attributed to WTT usage were identified. For patients with radiographic follow-up (96%; mean duration 14 ± 12 mo), PJK occurred in 15% (mean 1.8 ± 1.0 mo postoperatively). Proximal junctional angle increased an average 4° (10° to 14°, P = .004). Rates of symptomatic PJK and revision for PJK were 8.8% and 2.9%, respectively. CONCLUSION: Preliminary results support the safety of the WTT for PJK prophylaxis. Approximately 15% of patients developed radiographic PJK, no complications were directly attributed to WTT usage, and the revision rate for PJK was low. These early results warrant future research to assess longer-term efficacy of the WTT for PJK prophylaxis in ASD surgery.

The Berbeo-Sardi Angle (BSA): An Innovative Method to Effectively Estimate Pelvic Retroversion in Anteroposterior Radiographs-A Correlation With Traditional Parameters.

STUDY: Design: Diagnostic studies-concordance between diagnostic tests. OBJECTIVES: The purpose of this study was to develop a novel spinopelvic parameter (Berbeo-Sardi angle [BSA], the angle formed at the intersection of a line that connects the inferior margin of the sacroiliac joint to the midpoint of a horizontal line joining both femoral heads) measurable in anteroposterior radiographs that indirectly estimates pelvic retroversion and correlates with traditional measurements like pelvic tilt (PT). SUMMARY: Sagittal balance appraisal and surgical planning rely on the interpretation of spinopelvic parameters. An increased PT reflects pelvic retroversion as a compensatory mechanism to limit sagittal imbalance and correlates with increased pain and disability. However, poor imaging techniques and incorrect patient positioning frequently hamper landmark identification in lateral radiographs, and with no measurable angles in anteroposterior radiographs, it is often impossible to determine PT and pelvic retroversion. METHODS: Whole-spine radiographs from 105 consecutive patients were used to retrospectively measure conventional spinopelvic parameters and the BSA. Intraclass correlation coefficient was used to assess a quantitative correlation between the PT and BSA as indirect measures of pelvic retroversion. RESULTS: Average values for pelvic incidence, lumbar lordosis, sacral slope, PT, and BSA were 46.5° (±10.23), 48.56° (±12.30), 29.97° (±9.77), 16.94° (±8.03), and 54.47° (±4.05), respectively. We encountered a moderately strong correlation (r = -0.66) between PT and BSA. Receiver operating characteristic plot analysis revealed that a BSA threshold of 46° has a sensitivity of 90% to identify pathologic PT values (>20°), whereas a BSA ≥60° has a specificity of 90% to rule out pelvic retroversion using anteroposterior radiographs. CONCLUSIONS: There is a moderately strong correlation between the BSA, an innovative spinopelvic parameter measurable in anteroposterior radiographs, and PT. BSA seems to show great promise in simplifying spinopelvic appraisal by easily estimating pelvic retroversion associated with sagittal imbalance, while avoiding image-quality issues often encountered in lateral radiographs. LEVEL OF EVIDENCE: Level III.

The Alar Ligaments: A Cadaveric and Radiologic Comparison Study.

OBJECTIVE: A precise anatomical description of the alar ligaments is important to better understand their biomechanical and pathologic implications. Although there are several studies regarding their anatomy, the literature is inconsistent. To our knowledge, there are no reports that compare cadaveric morphologic findings with computed tomography (CT) images of the alar ligaments. METHODS: Eight sides from 4 fresh-frozen cadaveric specimens were used in this study. After routine dissection of the craniocervical junction, the alar ligaments were exposed. We carried out measurements of the alar ligaments, their position within the craniovertebral junction, and their relation to the dens and adjacent structures. Fine-cut CT of the specimens was performed, and the measurements were later compared with the original cadaveric dissections. RESULTS: Alar ligaments were attached to the upper half of the lateral surface of the dens and ran laterally to its insertion just medial to the occipital condyle. The ligaments were found to have an ovoid cross-sectional area with a nearly horizontal caudocranial trajectory and comparable diameters in both anteroposterior and superoinferior directions between the CT and cadaveric measurements. CONCLUSIONS: There were small but not statistically significant differences in the measurements between the cadaver specimens and the CT images. There was however, a strong correlation between the proximal and distal insertions, as well as the orientation of the fibers, that suggests CT images can be an appropriate approach to the study of the anatomical and 3-dimensional features of the alar ligaments.

First Gross Anatomic Findings of an Os Odontoideum.

BACKGROUND: Os odontoideum is an uncommon abnormality of the craniovertebral junction where the tip of the odontoid process lacks continuity with the body of C2. The clinical presentation is variable, but severe neurologic impairment can result. CASE DESCRIPTION: We report the gross and radiologic findings of a cadaver found to harbor an os odontoideum. CONCLUSIONS: To our knowledge, there are no cadaveric reports in the literature regarding an os odontoideum. Such a case allows a rare window into the anatomy and relationships of this pathologic structure.

Anatomic Variations of the Anterior Atlantodental Joint and Relations to the Apical and Alar Ligaments in a Geriatric Population.

BACKGROUND: Degenerative changes in the upper cervical spine may be age related degeneration or a pathological process such as rheumatoid arthritis. However, to our knowledge, the relationship between the apical and alar ligaments and these anomalies has not been discussed. We present anatomical variations of the anterior atlantodental joint observed during cadaveric dissection of adult craniovertebral junctions, the relationship with the alar and apical ligaments and discuss possible origins and clinical implications. METHODS: The upper cervical spine including part of the occiput was dissected from cadavers whose mean age at death was 78.9 years-old. The anterior atlantodental joint and apical and alar ligaments were observed and any atypical findings were noted. RESULTS: In eleven specimens, seven had a dens corona, three had an os odontoideum and one had a dens aureola, which arose from the upper part of the anterior arch of the atlas. Only four specimens had an apical ligament. CONCLUSIONS: The possible etiologies and the clinical applications of these craniovertebral anomalies in a geriatric population should be appreciated by the clinician treating patients with disease in this area or interpreting imaging in the region.

Anatomy of the Alar Ligament: Part II: Variations of Its Attachment onto the Dens.

OBJECTIVE: Various authors have described the morphology of the alar ligaments; however, there are no reports of a cadaveric study focusing on their attachments onto the dens. The purpose of this study was to use fresh cadaveric specimens to describe in detail different attachment patterns of the alar ligaments onto the dens. METHODS: This study used 22 sides from 11 fresh frozen cadaveric heads. Specimens were obtained from 8 men and 3 women who were 67-99 years old at death. Dissection of the exact attachment of the alar ligaments onto the dens was observed from posterior, superior, and anterior views under the surgical microscope. RESULTS: From a posterior view, 6 alar ligaments passed over the tip of the dens, and 16 alar ligaments attached onto the posterolateral part of the dens; the right and left ligaments had no continuity. From a superior view, the alar ligament was classified in 2 ways: depending on the covered area of the dens (entirely or posterior two thirds) and continuity of the alar ligament (transversely, separately, or combination). Fourteen alar ligaments covered the posterior two thirds of the dens. From an anterior view, in 1 specimen, the alar ligament extended to the anterior surface of the dens. CONCLUSIONS: Wide posterolateral anchoring to the dens coupled with the nearly horizontal trajectory explains the biomechanical advantage of the alar ligaments in undertaking a stabilizing function in limiting head rotation that would otherwise be ineffective in the case of weaker attachments or a more vertical orientation.

Anatomy of Alar Ligament Part III: Biomechanical Study.

OBJECTIVE: Four layers of ligamentous stabilizers comprise the craniocervical junction, and the second layer is composed of apical and paired alar ligaments. The purpose of this study is to establish the tensile strength of the alar ligaments for better understanding the implications that can arise from trauma and other pathologies in the craniocervical region. METHODS: Nineteen sides from 10 fresh frozen adult cadaveric Caucasian heads were used in this study. The specimens were derived from 6 males and 4 females, and the age of the cadavers at death ranged from 67-90 years old. To measure the tensile strength, a tensile testing machine (M2-200, Mark-10 Corporation, Copiague, New York, USA) was used in this study. RESULTS: The force (N) necessary until failure for all alar ligaments ranged from 87-346 N with a mean of 186.9 ± 69.7 N. There was a significant difference when comparing tensile strength between males and females. CONCLUSIONS: Further studies will be necessary to determine their importance as secondary stabilizers and measure their ability to support similar forces when subject to rotation and lateral bending forces, as well as with flexion-extension.

Relationship of the Median and Radial Nerves at the Elbow: Application to Avoiding Injury During Venipuncture or Other Invasive Procedures of the Cubital Fossa.

INTRODUCTION: The median and radial nerves are two important neural structures found in the cubital fossa. The trajectory and landmarks used to identify their location are important when procedures are done in this area. METHODS AND MATERIALS: Ten fresh-frozen cadavers were dissected (20 upper limbs) and measurements were taken from the medial epicondyle to the median and radial nerves as well as to the lateral epicondyle of each limb. RESULTS: The distance between the medial epicondyle and the median nerve was found to be three centimeters with a range of 2.1 to four centimeters and the distance from the medial epicondyle to the radial nerve had a mean distance of 5.5 cm and a range of 3.8 to seven centimeters. DISCUSSION: Damage to the median or radial nerves can lead to major complications including loss of extension, flexion, and sensation in the forearm and hand. Other studies have tried to identify the course of these nerves in order to prevent their injury during procedures. CONCLUSION: After identifying the medial epicondyle, using the results we obtained, physicians may have a better understanding of where the median and radial nerves lie within the cubital fossa when performing procedures in this area.

Osborne's Ligament: A Review of its History, Anatomy, and Surgical Importance.

When discussing the pathophysiology of ulnar neuropathy, Geoffrey Vaughan Osborne described a fibrous band that can be responsible for the symptoms seen in this disorder. In this paper, we take a glimpse at the life of Osborne and review the anatomy and surgical significance of Osborne's ligament. This band of tissue connects the two heads of the flexor carpi ulnaris and thus forms the roof of the cubital tunnel. To our knowledge, no prior publication has reviewed the history of this ligament, and very few authors have studied its anatomy in any detail. Therefore, the aim of the present paper is to elucidate this structure that is often implicated and surgically transected to decompress the ulnar nerve at the elbow.