Single-Level Anterolateral and Posterior Interbody Fusion Techniques are Associated with Equivalent Long-Term Lumbar Reoperations.

STUDY DESIGN: Retrospective Cohort Study. OBJECTIVE: This study compares reoperation rates and complications following single-level ALIF/LLIF and TLIF/PLIF. SUMMARY OF BACKGROUND DATA: Anterior lumbar interbody fusion (ALIF), lateral lumbar interbody fusion (LLIF), transforaminal lumbar interbody fusion (TLIF), and posterior lumbar interbody fusion (PLIF) are widely used for degenerative disc disease. Lumbar interbody fusions have high rates of reoperation primarily related to adjacent segment pathology and pseudarthrosis. METHODS: The PearlDiver database was queried for patients (2010-2021) who had single-level ALIF/LLIF or TLIF/PLIF with same-day, single-level posterior instrumentation. ALIF/LLIF were combined and similarly, TLIF/PLIF were combined, given how these operations are indistinguishable with Current Procedural Terminology (CPT) coding. All patients were followed for ≥2 years and excluded if they had spinal traumas, fractures, infections, or neoplasms prior to surgery. The two cohorts, ALIF/LLIF and TLIF/PLIF, were matched 1:1 based on age, sex, Elixhauser-Comorbidity Index (ECI), smoking status, and diabetes. The primary outcome was the incidence of all-cause subsequent lumbar operations. Secondary outcomes included 90-day surgical complications. RESULTS: After 1:1 matching, each cohort contained 14,070 patients. All-cause subsequent lumbar operations were nearly identical at 5-year follow-up (9.4% ALIF/LLIF vs. 9.5% TLIF/PLIF, P=0.91) (Table 2). Survival analysis using all-cause subsequent lumbar operations as the endpoint showed an equivalent 10-year survival rate of 86.0% (95%CI: 85.2-86.8) (Figure 1). Within 90 days, TLIF/PLIF had more infections (1.3% vs. 1.7%, P=0.007) and dural injuries (0.2% vs. 0.4%, P=0.001). There was no difference in wound dehiscence, hardware complications, or medical complications (Table 3). CONCLUSION: As utilized in real-world clinical practice, single-level anterolateral versus posterior approaches for interbody fusion have no effect on long term reoperation rates.

Intervertebral disc human nucleus pulposus cells associated with back pain trigger neurite outgrowth in vitro and pain behaviors in rats.

Low back pain (LBP) is often associated with the degeneration of human intervertebral discs (IVDs). However, the pain-inducing mechanism in degenerating discs remains to be elucidated. Here, we identified a subtype of locally residing human nucleus pulposus cells (NPCs), generated by certain conditions in degenerating discs, that was associated with the onset of discogenic back pain. Single-cell transcriptomic analysis of human tissues showed a strong correlation between a specific cell subtype and the pain condition associated with the human degenerated disc, suggesting that they are pain-triggering. The application of IVD degeneration-associated exogenous stimuli to healthy NPCs in vitro recreated a pain-associated phenotype. These stimulated NPCs activated functional human iPSC-derived sensory neuron responses in an in vitro organ-chip model. Injection of stimulated NPCs into the healthy rat IVD induced local inflammatory responses and increased cold sensitivity and mechanical hypersensitivity. Our findings reveal a previously uncharacterized pain-inducing mechanism mediated by NPCs in degenerating IVDs. These findings could aid in the development of NPC-targeted therapeutic strategies for the clinically unmet need to attenuate discogenic LBP.

Postoperative Spinal Cerebrospinal Fluid-Venous Fistulas Associated With Dural Tears in Patients With Intracranial Hypotension or Superficial Siderosis-A Digital Subtraction Myelography Study.

BACKGROUND: Postoperative spinal cerebrospinal fluid (CSF) leaks are common but rarely cause extensive CSF collections that require specialized imaging to detect the site of the dural breach. OBJECTIVE: To investigate the use of digital subtraction myelography (DSM) for patients with extensive extradural CSF collections after spine surgery. METHODS: A retrospective review was performed to identify a consecutive group of patients with extensive postoperative spinal CSF leaks who underwent DSM. RESULTS: Twenty-one patients (9 men and 12 women) were identified. The mean age was 46.7 years (range, 17-75 years). The mean duration of the postoperative CSF leak was 3.3 years (range, 3 months to 21 years). MRI showed superficial siderosis in 6 patients. DSM showed the exact location of the CSF leak in 19 (90%) of the 21 patients. These 19 patients all underwent surgery to repair the CSF leak, and the location of the CSF leak could be confirmed intraoperatively in all 19 patients. In 4 (19%) of the 21 patients, DSM also showed a CSF-venous fistula at the same location as the postoperative dural tear. CONCLUSION: In this study, DSM had a 90% detection rate of visualizing the exact site of the dural breach in patients with extensive postoperative spinal CSF leaks. The coexistence of a CSF-venous fistula in addition to the primary dural tear was present in about one-fifth of patients. The presence of a CSF-venous fistula should be considered if CSF leak symptoms persist in spite of successful repair of a durotomy.

Perioperative Complications Following Spine Surgery in Adult Patients with Achondroplasia.

STUDY DESIGN: Retrospective cohort study. OBJECTIVES: To describe the common types of complications and their risk factors during spine surgery in patients with achondroplasia. METHODS: A retrospective review was performed of medical records of adult achondroplasia patients who underwent spine surgery at our institution between 2007 and 2021. Inclusion criteria were achondroplasia and age >16 years. Surgical encounters were evaluated for durotomy, postoperative neurologic deficit, wound compromise, medical complications, and return to the operating room. Statistical analysis included evaluation of relationships across complications and fisher exact test applied to bivariate/categorical variables and t-test/ANOVA for continuous variables. Multivariable analysis using logistic regression was performed to account for patient characteristics. RESULTS: Fifty-five patients with achondroplasia underwent 95 surgeries. Forty-nine percent of the surgeries involved a complication. These included durotomy (33.7%), neurologic deficit (11.6%), wound compromise (6.3%), and other medical complications (6.3%). Thirteen percent of surgeries required return to the operating room. The greatest number of complications occurred in thoracolumbar region (60.0%) compared to cervicothoracic (18.2%) and craniocervical junction (33.3%). Chronologically later surgical encounters had decreased complications and durotomies only occurred in thoracolumbar surgeries (45.7%). CONCLUSIONS: Adult patients with achondroplasia undergoing surgery chronologically later in this set of consecutive patients were at a decreased risk for complications. Thoracolumbar surgeries were at the greatest risk for durotomies. Male sex was a risk factor for durotomy, while age was a risk factor for neurologic deficit. The potential for adverse surgical events should be considered when evaluating patients with achondroplasia for spine surgery. .

Adjacent Segment Impingement: A New Type of Adjacent Segment Disease?: A Report of 3 Cases.

CASE: We present 3 cases in which spinal rods extending beyond the intended level of fusion caused injury to adjacent structures, which we term "adjacent segment impingement." All cases presented as back pain with no neurological symptoms, with a minimum 6 years of follow-up from the initial procedure. Treatment consisted of extending the fusion to include the affected adjacent segment. CONCLUSION: We recommend surgeons check to ensure spinal rods are not abutting adjacent level structures at the time of the initial implant while considering that adjacent levels may move closer to the rod during spine extension or twisting.

Occipitocervical fusion of traumatic atlanto-occipital dissociation in a patient with autofused cervical facet joints: illustrative case.

BACKGROUND: Patients who survive traumatic atlanto-occipital dissociation (AOD) may present with normal neurological examinations and near-normal-appearing diagnostic images, such as cervical radiographs and computed tomography (CT) scans. OBSERVATIONS: The authors described a neurologically intact 64-year-old female patient with a degenerative autofusion of her right C4-5 facet joints who presented to their center after a motor vehicle collision. Prevertebral soft tissue swelling and craniocervical subarachnoid hemorrhage prompted awareness and consideration for traumatic AOD. An abnormal occipital condyle-C1 interval (4.67 mm) on CT and craniocervical junction ligamentous injury on magnetic resonance imaging (MRI) confirmed the diagnosis of AOD. Her autofused right C4-5 facet joints were incorporated into the occipitocervical fusion construct. LESSONS: Traumatic AOD can be easily overlooked in patients with a normal neurological examination and no associated upper cervical spine fractures. A high index of suspicion is needed when evaluating CT scans because normal values for craniocervical parameters are significantly different from the accepted ranges of normal on radiographs in the adult population. MRI of the cervical spine is helpful to evaluate for atlanto-occipital ligamentous injury and confirm the diagnosis. Occipitocervical fusion construct may need to be extended to incorporate spinal levels with degenerative autofusion to prevent adjacent level degeneration.

Evaluation of tortuous vertebral arteries before cervical spine surgery: illustrative case.

BACKGROUND: Cervical spine surgery sometimes necessitates complex ventral/dorsal approaches or osteotomies that place the vertebral artery (VA) at risk of inadvertent injury. Tortuosity of the VA poses increased risk of vessel injury during anterior decompression or placement of posterior instrumentation. OBSERVATIONS: In this report, the authors describe a patient with degenerative cervical spondylotic myelopathy and focal kyphotic deformity requiring corrective surgery via a combined ventral/dorsal approach. Computed tomography (CT) and CT angiography (CTA) of the spine identified a left medially enlarged C4 transverse foramen and tortuous VA V2 segment forming a potentially dangerous medial loop into the vertebral body, respectively. The patient's presentation and management are described. LESSONS: The course of the VA is variable, and a tortuous VA with significant medial or lateral displacement may be dangerous during ventral and dorsal approaches to the cervical spine. CTA of the cervical spine is warranted in cases in which atlantoaxial fixation is needed or suspicious transverse foramen morphology is identified to understand the course of the VA and identify anatomical variations that would put the VA at risk during cervical spine surgery.

Motion preserving management of unstable traumatic clivus fracture extending through bilateral occipital condyles.

We describe non-operative management a rare traumatic clival fracture extending through the bilateral occipital condyles. Clinical History: A 26-year-old female who was involved in a high-speed motor vehicle crash presented to an outside facility with difficulty speaking. Subsequent CT of the cervical spine demonstrated a fracture of the clivus with extension through the bilateral occipital condyles. She was then transferred to our hospital for further management where complete trauma survey noted multiple other injuries including traumatic subarachnoid hemorrhage, spinal epidural hematoma, bilateral pneumothoraces, liver laceration, bilateral upper extremity injuries, and lumbosacral fractures. Additional spinal imaging was negative for any associated vascular or spinal cord injury. Given her young age, there was a strong interest to preserve craniocervical motion and the decision was made to treat her with non-operatively with halo placement. After 18 weeks of rigid fixation, follow up imaging demonstrated completely healed fractures and at twenty-one weeks post fixation she demonstrated preserved motion of the craniocervical junction. This is a review of the literature and case report regarding this rare entity and its management.

NF-κB inhibitor, NEMO-binding domain peptide attenuates intervertebral disc degeneration.

BACKGROUND CONTEXT: Nonphysiological mechanical loading and inflammation are both critically involved in intervertebral disc (IVD) degeneration, which is characterized by an increase in cytokines and matrix metalloproteases (MMPs) in the nucleus pulposus (NP). This process is known to be mediated by the NF-κB pathway. CLINICAL SIGNIFICANCE: Current clinical treatments for IVD degeneration focus on the alleviation of symptoms rather than targeting the underlying mechanism. Injection of an NF-κB inhibitor may attenuate the progression of IVD degeneration. PURPOSE: To investigate the ability of the NF-κB inhibitor, NEMO binding domain peptide (NBD), to alter IVD degeneration processes by reducing IL-1ß- and mechanically-induced cytokine and MMP levels in human nucleus pulposus cells in vitro, and by attenuating IVD degeneration in an in vivo rat model for disc degeneration. STUDY DESIGN: Experimental in vitro and animal model. PATIENT SAMPLE: Discarded specimens of lumbar disc from 21 patients, and 12 Sprague Dawley rats. OUTCOME MEASURES: Gene and protein expression, cell viability, µMRI and histology. METHODS: IL-1ß-prestimulated human nucleus pulposus cells embedded into fibrin constructs were loaded in the Flexcell FX-5000 compression system at 5 kPa and 1 Hz for 48 hours in the presence and absence of NBD. Unloaded hNPC/fibrin constructs served as controls. Cell viability in loaded and unloaded constructs was quantified, and gene and protein expression levels determined. For in vivo testing, a rat needle disc puncture model was employed. Experimental groups included injured discs with and without NBD injection and uninjured controls. Levels of disc degeneration were determined via µMRI, qPCR and histology. Funding sources include $48,874 NASS Young Investigator Research Grant and $119,174 NIH 5K01AR071512-02. There were no applicable financial relationships or conflicts of interest. RESULTS: Mechanical compression of hNPC/fibrin constructs resulted in upregulation of MMP-3 and IL-8. Supplementation of media with 10 µM NBD during loading increased cell viability, and decreased MMP-3 gene and protein levels. IVD injury in rat resulted in an increase in MMP-3, IL-1ß and IL-6 gene expression. Injections of 250 µg of NBD during disc injury resulted in decreased IL-6 gene expression. µMRI analysis demonstrated a reduction of disc hydration in response to disc needle injury, which was attenuated in NBD-treated IVDs. Histological evaluation showed NP and AF lesion in injured discs, which was attenuated by NBD injection. CONCLUSIONS: The results of this study show NBD peptide's capacity to reduce IL-1ß- and loading-induced MMP-3 levels in hNPC/fibrin constructs while increasing the cells' viability, and to attenuate IVD degeneration in rat, involving downregulation of IL-6. Therefore, NBD may be a potential therapeutic agent to treat IVD degeneration.

Unusual Exophytic Appearance of Spinal Cord Subependymoma.

BACKGROUND: Subependymomas are rare in the spinal cord. They are typically expansile, intramedullary spinal cord masses, eccentrically located with minimal gadolinium enhancement. CASE DESCRIPTION: We present a case of subependymoma originating from the cervical cord with an unusual exophytic appearance. Hallmarks of subependymoma and treatment are reviewed. CONCLUSIONS: This is the first case, to our knowledge, where imaging revealed a mass appearing to be completely extramedullary with a primary exophytic component. Therefore, subependymomas should remain on the differential for masses in the spinal cord that appear extramedullary and exophytic.

Biomechanical evaluation of a simulated T-9 burst fracture of the thoracic spine with an intact rib cage.

OBJECT: Classic biomechanical models have used thoracic spines disarticulated from the rib cage, but the biomechanical influence of the rib cage on fracture biomechanics has not been investigated. The well-accepted construct for stabilizing midthoracic fractures is posterior instrumentation 3 levels above and 2 levels below the injury. Short-segment fixation failure in thoracolumbar burst fractures has led to kyphosis and implant failure when anterior column support is lacking. Whether shorter constructs are viable in the midthoracic spine is a point of controversy. The objective of this study was the biomechanical evaluation of a burst fracture at T-9 with an intact rib cage using different fixation constructs for stabilizing the spine. METHODS: A total of 8 human cadaveric spines (C7-L1) with intact rib cages were used in this study. The range of motion (ROM) between T-8 and T-10 was the outcome measure. A robotic spine testing system was programmed to apply pure moment loads (± 5 Nm) in lateral bending, flexion-extension, and axial rotation to whole thoracic specimens. Intersegmental rotations were measured using an optoelectronic system. Flexibility tests were conducted on intact specimens, then sequentially after surgically induced fracture at T-9, and after each of 4 fixation construct patterns. The 4 construct patterns were sequentially tested in a nondestructive protocol, as follows: 1) 3 above/2 below (3A/2B); 2) 1 above/1 below (1A/1B); 3) 1 above/1 below with vertebral body augmentation (1A/1B w/VA); and 4) vertebral body augmentation with no posterior instrumentation (VA). A repeated-measures ANOVA was used to compare the segmental motion between T-8 and T-10 vertebrae. RESULTS: Mean ROM increased by 86%, 151%, and 31% after fracture in lateral bending, flexion-extension, and axial rotation, respectively. In lateral bending, there was significant reduction compared with intact controls for all 3 instrumented constructs: 3A/2B (-92%, p = 0.0004), 1A/1B (-63%, p = 0.0132), and 1A/1B w/VA (-66%, p = 0.0150). In flexion-extension, only the 3A/2B pattern showed a significant reduction (-90%, p = 0.011). In axial rotation, motion was significantly reduced for the 3 instrumented constructs: 3A/2B (-66%, p = 0.0001), 1A/1B (-53%, p = 0.0001), and 1A/1B w/VA (-51%, p = 0.0002). Between the 4 construct patterns, the 3 instrumented constructs (3A/2B, 1A/1B, and 1A/1B w/VA) showed comparable stability in all 3 motion planes. CONCLUSIONS: This study showed no significant difference in the stability of the 3 instrumented constructs tested when the rib cage is intact. Fractures that might appear more grossly unstable when tested in the disarticulated spine may be bolstered by the ribs. This may affect the extent of segmental spinal instrumentation needed to restore stability in some spine injuries. While these initial findings suggest that shorter constructs may adequately stabilize the spine in this fracture model, further study is needed before these results can be extrapolated to clinical application.