The Cervical Intervertebral Foramen: Microanatomy, Pathology, and Clinical Implications.

STUDY DESIGN: This is an evidence-based narrative review article. OBJECTIVE: We hope to provide a primer on cervical intervertebral foramen (cIVF) anatomy for spine surgeons, interventionalists, and physiatrists who regularly treat cervical spine pathology, and encourage further exploration of this topic. BACKGROUND: This corridor for exiting cervical nerve roots is characterized by its intricate microanatomy involving ligamentous, nervous, and vascular structures. Degenerative changes such as facet hypertrophy and disc herniations alter these relationships, potentially leading to nerve root compression and cervical radiculopathy. METHODS: This review synthesizes existing knowledge on the cIVF. Key imaging, cadaveric, and clinical studies serve as a foundation for this anatomic review. RESULTS: We explore topics such as dynamic changes that affect foraminal size and their implications for nerve root compression, the relationship of the dorsal root ganglion to the cervical foramen, and the function and clinical significance of foraminal ligaments, arteries, and veins. CONCLUSIONS: Changes in the cIVF are frequently the basis of cervical degenerative pathologies. A comprehensive understanding of its microanatomical structure will allow the practitioner to better treat the underlying disease process causing their symptoms and signs.

Twenty-Year Radiographic Outcomes Following Single-Level Cervical Disc Arthroplasty: Results From a Prospective Randomized Controlled Trial.

STUDY DESIGN: Prospective randomized controlled trial. OBJECTIVE: Compare range of motion (ROM) and adjacent segment degeneration (ASD) following cervical disc arthroplasty (CDA) versus anterior cervical discectomy and fusion (ACDF) at 20-year follow-up. SUMMARY OF BACKGROUND DATA: Anterior cervical discectomy and fusion is the standard of treatment for single-level cervical disc degeneration causing radiculopathy. CDA is claimed to reduce shear strain, and adjacent-level ROM changes are hypothesized to hasten ASD with ACDF. MATERIALS AND METHODS: This study collected data on 47 patients randomized to ACDF or CDA. Lateral cervical spine radiographs were evaluated preoperatively, postoperatively, and at 20 years for alignment, ROM, ASD, and heterotopic ossification. RESULTS: Eighty-two percent (18/22) of CDA patients and 84% (21/25) of ACDF patients followed up at 20 years. At 20 years, total cervical (C2-C7) ROM was statistically different between the CDA and fusion groups (47.8° vs . 33.4°, P =0.005). Total cervical ROM was not significantly different between preoperative and 20-year periods following CDA (45.6° vs . 47.4°, P =0.772) or ACDF (40.6° vs . 33.0°, P =0.192). Differences in postoperative and 20-year index-level ROM following CDA were not significant (10.1° vs . 10.2°, P =0.952). Final ASD grading was statistically lower following CDA versus ACDF at both adjacent levels ( P <0.005). Twenty-year adjacent-level ossification development was increased following ACDF versus CDA ( P <0.001). Polyethylene mean thickness decreased from 9.4 mm immediately postoperatively to 9.1 mm at 20-year follow up ( P =0.013). Differences in adjacent-level ROM from preoperative to 20-year follow-up in both the ACDF and CDA groups did not meet statistical significance ( P >0.05). CONCLUSIONS: Cervical disc arthroplasty maintains index-level and total cervical ROM with very long-term follow-up. Total cervical ROM was higher at 20 years in CDA relative to ACDF. CDA results in lower rates of ASD and adjacent-level ossification development than ACDF.

Technique Pearls for Successful Cervical Disc Arthroplasty From More Than 20 Years of Surgical Experience.

STUDY DESIGN: Surgical technique paper. OBJECTIVE: To describe tips and pearls for cervical disc arthroplasty (CDA). BACKGROUND: CDA has proven to be an effective means of treatment for degenerative cervical disc disease and cervical radiculopathy in properly selected patients who have previously failed non-operative treatment. METHODS: Surgical tips and pearls garnered from more than 20 years of experience with CDA surgery are described. RESULTS: This discussion focuses on pearls for successful procedures, including patient selection, patient positioning, surgical technique, and postoperative protocols. CONCLUSIONS: In correctly selected patients, CDA can be effective in treating cervical degenerative disc disease and radiculopathy. The techniques described here can increase the chance of success and decrease complications.

The Relationship Between Patient Demographic and Clinical Characteristics and Successful Treatment Outcomes After Basivertebral Nerve Radiofrequency Ablation: A Pooled Cohort Study of Three Prospective Clinical Trials.

OBJECTIVE: Multiple studies have demonstrated the safety and effectiveness of basivertebral nerve radiofrequency ablation (BVN RFA) for improving low back pain related to the vertebral endplate. However, the influence of patient demographic and clinical characteristics on treatment outcome is unknown. DESIGN: Pooled cohort study of three clinical trials of patients with vertebral endplate pain identified by Type 1 and/or Type 2 Modic changes and a correlating presentation of anterior spinal element pain. SETTING: Thirty-three global study centers. SUBJECTS: Patients (n = 296) successfully treated with BVN RFA. METHODS: Participant demographic and clinical characteristics were analyzed with stepwise logistic regression to identify predictors of treatment success. Three definitions of treatment success were defined: 1) ≥50% visual analog scale pain improvement, 2) ≥15-point Oswestry Disability Index (ODI) improvement, and 3) ≥50% visual analog scale or ≥15-point ODI improvement from baseline. RESULTS: Low back pain of ≥5 years' duration and higher ODI scores at baseline increased the odds of treatment success, whereas baseline opioid use and higher Beck Depression Inventory scores reduced these odds. However, the three regression models demonstrated receiver-operating characteristics of 62-70% areas under the curve, and thus, limited predictive capacity. CONCLUSIONS: This analysis identified no demographic or clinical characteristic that meaningfully increased or reduced the odds of treatment success from BVN RFA. On the basis of these findings and the high response rates from the three analyzed trials, we recommend the use of objective imaging biomarkers (Type 1 and/or 2 Modic changes) and a correlating presentation of anterior spinal element pain to determine optimal candidacy for BVN RFA.

Comparison of a right versus left sided anterior approach to the thoracic and thoracolumbar spine: A case series.

Aims & objectives: Traditionally, a left sided anterior approach has been considered the safest way to access the thoracic and thoracolumbar spine due to avoidance of the inferior vena cava (IVC). We challenge this 'go from the left' dogma by presenting a series of patients who underwent a right sided approach to the thoracic and thoracolumbar spine. Materials & methods: 71 anterior thoracic fusion procedures treated with either a left or right sided approach were identified and retrospectively studied. Demographic information, indication for surgery, intra-operative time, estimated blood loss (EBL), hospital length of stay (LOS), and complications were collected. Patients were further sub divided into groups according to indication for surgery. Results: 57 cases with a right sided approach and 14 cases with a left sided approach were investigated. Four mortalities occurred, all within the right sided approach group among patients who were being for osteomyelitis/discitis. There were statistically significant differences between right and left sided approach groups for operative time and EBL when patients were analysed together favoring the left sided approach. However once subgroup analysis was performed, there were no statistically significant differences between right and left sided approach groups aside from operative time in the HNP group and LOS in the fracture group. Neither group had catastrophic intra-operative vascular injury. Perioperative complications occurred in 22.8% of right sided approach patients and 14% of left sided approach patients. Conclusions: Our results reinforce the fact that anterior thoracic fusion is a major surgical endeavor that is not without risk. Although there were differences in operative time and EBL between right and left sided approach groups when all patients were analysed together, these were no longer significant with subgroup analysis according to indication for surgery with two exceptions. This may be in part due to low sample size or confounding variables related to indication.

Comparison of Lumbar Fusion With and Without Interbody Fusion for Lumbar Stenosis Using Patient-Reported Outcomes Measurement Information System (PROMIS) Computer Adaptive Testing (CAT).

Study design This was a retrospective analysis of patient-reported outcomes across a two-year period. Summary of background data Patients suffering from lumbar stenosis may experience low back pain, neurogenic claudication, and weakness. Patients can benefit from surgical intervention, including decompression with or without fusion. However, the superiority of any single fusion construct remains controversial. Objective The goal of this study was to compare Patient-Reported Outcomes Measurement Information System (PROMIS®) Computer Adaptive Testing (CAT) measures in patients with lumbar spinal stenosis treated surgically with lumbar decompression and fusion with or without interbody fusion. Methods A retrospective review of patients with lumbar stenosis undergoing lumbar decompression and one-level fusion was performed. PROMIS® CAT Physical Function (PF) and Pain Interference (PI) assessments were administered using a web-based platform pre and postoperatively. Results Sixty patients with lumbar stenosis undergoing one-level lumbar fusion were identified. Twenty-seven patients underwent posterior lumbar fusion (PSF) alone and 33 underwent one-level lumbar interbody fusion (IF). Patients undergoing IF had better absolute PF scores compared to patients undergoing PSF at one-year postoperatively (48.9 v 41.6, p=0.002) and greater relative improvement in PF scores from baseline at one-year postoperatively (D13.6 v D8.6, p=0.02). A subgroup analysis of patients undergoing TLIF v PSF showed better absolute PF scores at the one-year follow-up in the TLIF group (47.1 v 42.3, p=0.04). No differences were found in PI scores at any time point between the PSF and IF groups. Patients undergoing IF had significantly shorter hospital stays (2.5 v 3.3 days, p=0.02) compared to patients undergoing PSF. Conclusions Patients with lumbar spinal stenosis treated with one-level IF reported higher absolute PF scores and experienced greater relative improvement in PF scores from baseline at one-year follow-up compared to patients treated with PSF alone. Additionally, IF is associated with a decreased length of hospital stay as compared to PSF.

Safe Spine Surgery During the COVID-19 Pandemic.

Safe spine surgery is possible during the COVID-19 pandemic. Certain urgent procedures must still be performed during this challenging time to prevent permanent long-term disability or death for patients. Precautions must be taken in the operating room to optimize safety, including the use of personal protective equipment and appropriate room setup and anesthesia and equipment optimization. Evidence-based guidelines to create a safe operative paradigm for use in future viral outbreaks are paramount.

Intra-Articular Sacroiliac Joint Injection: Technical Guide.

Sacroiliac (SI) joint pathology has been an increasingly discussed pathology as a potential etiology for significant low back and lower extremity pain. While patient history and examination maneuvers can assist with identifying the SI joint as a potential cause of pain, an intra-articular SI joint injection is critical to properly diagnose the SI joint as a clinically relevant pain generator. In addition to the diagnostic information from the injection, SI joint intra-articular injections can be performed for therapeutic benefit as part of a multi-modal, conservative treatment approach for SI joint pathology. We discuss our technique for safe and effective SI joint intra-articular injections as a both diagnostic and therapeutic aid for SI joint pathology.

Far Lateral/Extraforaminal Approaches for Microdiscectomy and Foraminal Decompression in the Lumbar Spine.

Far lateral approaches to the lumbar spine are uncommon procedures but are essential techniques for spine surgeons to understand and master for the treatment of extraforaminal disk herniations and foraminal stenosis. We present our preferred approaches for open and minimally invasive techniques to perform extraforaminal decompressions and/or discectomies in the lumbar spine.

Two-Level Anterior Cervical Discectomy and Fusion Versus Cervical Disc Arthroplasty-Long-Term Evidence Update.

BACKGROUND: Multiple studies have highlighted the motion-sparing benefits of single-level cervical disc arthroplasty (CDA) compared with anterior cervical discectomy and fusion (ACDF). However, few studies have reviewed multilevel ACDF versus CDA. Several recent studies have midterm and even long-term data available comparing 2-level ACDF versus CDA. METHODS: We reviewed 3 reports from 2 large randomized, prospective Food and Drug Administration investigational drug exemption trials looking at 2-level CDA versus ACDF, which provide the bulk of the available midterm to long-term, high-level evidence for the topic. We also present several smaller and/or shorter-term studies. RESULTS: One 5-year study showed that, while both CDA and ACDF showed significant improvement in patient-reported outcome scores, CDA demonstrated greater improvement in Neck Disability Index (NDI) scores than ACDF (mean = -37 versus mean = -28, P = .0003), were more likely to be satisfied (96.4% versus 89.5%, P = .04), had fewer secondary surgeries (4% versus 16.2%, P = .0003), had fewer adjacent level reoperations (3.1% versus 11.4%), and developed less adjacent segment degeneration (50.7% versus 90.5%, P < .0001). Adverse events occurred more frequently with ACDF (8.6% versus 4.4%).Similarly, Lanman et al [Lanman TH, Burkus JK, Dryer RG, Gornet MF, McConnell J, Hodges SD. Long-term clinical and radiographic outcomes of the Prestige LP artificial cervical disc replacement at 2 levels: results from a prospective randomized controlled clinical trial. J Neurosurg Spine. 2017;27(1):7-19] showed that, at 7 years, while both groups demonstrated improvement in patient-reported outcomes, CDA had greater improvement in regard to NDI, neck pain, and Short Form (36) Physical Component Summary scores (each P < .001), had higher rates of satisfaction (94.8% versus 92.6%), had lower rate of secondary surgery at treated levels (4.2% versus 14.7%), and had a lower, albeit not statistically significant, rate of secondary surgeries at adjacent levels (6.5% versus 12.5%). Adverse events were more common with ACDF (7.2% versus 3.2%).More recently, Gornet et al [Gornet MF, Lanman TH, Burkus JK, et al. Two-level cervical disc arthroplasty versus anterior cervical discectomy and fusion: 10-year outcomes of a prospective, randomized investigational device exemption clinical trial. J Neurosurg Spine. 2019;31:508-518.] in 2019 reported 10-year data from the same clinical trial as the Lanman et al report comparing 2-level CDA (209 patients) versus ACDF (188 patients). With >84% follow-up for both groups at 10 years, they found that CDA demonstrated a statistically significantly improved rate of overall success (84% versus 62%) as compared with ACDF. Greater improvements were seen in several other outcome measures for CDA, including NDI, neurological success, and neck pain scores. The CDA group had a lower rate of serious implant-related adverse events and demonstrated a lower rate of needing a secondary surgery at an adjacent level, 9% versus 18% in the ACDF group. CONCLUSIONS: Results of 2 large randomized trials suggest similar-to-improved patient reported outcomes for multilevel CDA versus ACDF maintained out to midterm to long-term follow-up of 5-10 years, with lower rates of revision surgery at index and adjacent levels and lower rates of serious adverse device-related events. LEVEL OF EVIDENCE: 5. CLINICAL RELEVANCE: Comparison of the safety and efficacy of multi-level cervical disc arthroplasty and cervical discectomy and fusion.

Long-Term Radiographic and Functional Outcomes of Patients With Absence of Radiographic Union at 2 Years After Single-Level Anterior Cervical Discectomy and Fusion.

STUDY DESIGN: Retrospective radiographic investigation. OBJECTIVE: To evaluate the long-term radiographic and functional outcomes of patients in whom there is absence of radiographic union at 2 years after single-level anterior cervical discectomy and fusion (ACDF). METHODS: Thirty-one patients were evaluated at standard postoperative time intervals per index trial protocol. Plain film radiographic fusion criteria at the arthrodesis level was defined as interspinous motion (ISM) <1 mm with corresponding motion at a non-arthrodesed superjacent level ISM ≥4 mm. Radiographs and functional outcome measures were acquired at each follow-up visit. Delayed union was defined as lack of radiographic union by 24 months. RESULTS: Nine patients demonstrated radiographic evidence of delayed radiographic union at 24 months. Of those 9 patients, 5 patients demonstrated evidence of union during the follow-up period to 72 months. Despite the absence of radiographic union based on our criteria, 3 of the 4 remaining patients reported remarkable improvements in pain scores and functional outcomes. CONCLUSIONS: The natural history of delayed union at 24 months after ACDF was still favorable despite the prolonged delay in union. The majority of patients (5 of 9) without radiographic union at 24 months did proceed to radiographic union by final follow-up. In addition, patients that did not meet our criteria for fusion maintained postoperative improvements in patient-reported outcome scores. In summary, our study patients undergoing a single-level ACDF with asymptomatic radiographic delayed union at 24 months can expect maintained improvements in postoperative patient-reported outcomes scores and can still progress to successful radiographic fusion.

Evaluation of DIAM™ Spinal Stabilization System for lower lumbar disc degenerative disease: A randomized, prospective, single-site study.

OBJECTIVE: To determine the efficacy of DIAM Spinal Stabilization System compared with nonoperative treatment for patients with low back pain and lower lumbar disc degenerative disease. METHODS: A single center collected prospective outcomes data on 38 patients randomized to an interspinous device or non-operative treatment for symptomatic lumbar degenerative disc disease with treatment crossover allowed at 6 months. RESULTS: At all postoperative timepoints out to 2-years, statistically significant improvements in ODI and back pain scores were observed with the interspinous device. Clinically significant improvements (ODI >15-point improvement) were seen in 87.5% of DIAM patients at 2-years postoperatively. A high cross-over rate was noted from the non-operative cohort to the operative group (12 of 15) due to continued pain with nonoperative care. Additionally, 80% of patients receiving the DIAM implant reported a >15-point ODI reduction from pre-surgical scores at 2-year follow-up. CONCLUSION: The DIAM device demonstrates improvement in ODI and Back Pain scores maintained out to a 2-year follow-up timepoint and performed superior to conventional nonoperative treatment regimens commonly used in low back pain.

Update on Spinal Cord Injury Management.

The management of acute spinal cord injury requires a multidisciplinary approach to maximize patient outcomes and potential. Treatment of this injury involves both surgical and medical intervention. Medical intervention in acute spinal cord injury is aimed at decreasing the neurotoxic environment that occurs as part of the secondary injury. New neuroregenerative therapies are being developed.

Functional Outcomes Associated With Adjacent-level Ossification Disease 10 Years After Cervical Disc Arthroplasty or ACDF.

STUDY DESIGN: A retrospective review of a prospective, randomized control Food and Drug Administration (FDA) investigational device exemption trial comparing anterior cervical discectomy and fusion (ACDF) with Bryan cervical disc arthroplasty. OBJECTIVE: Determine the clinical significance of adjacent-level ossification disease (ALOD) on long-term functional outcomes after ACDF or arthroplasty. SUMMARY OF BACKGROUND DATA: ALOD occurs when the anterior longitudinal ligament and annulus adjacent to the index surgical level calcifies. As previously reported, ALOD happens more commonly after an arthrodesis than an arthroplasty. No investigation has previously examined 10-year clinical outcomes associated with ALOD. MATERIALS AND METHODS: Forty patients were included in the 10-year follow-up. The index level was radiographically blinded and the cephalad-adjacent level was evaluated for ALOD. These scores underwent statistical analysis to compare the 2 surgical groups (ACDF and arthroplasty) for differences in the development of ALOD at a decade follow-up. Two investigational groups, on the basis of a high or low ALOD score, then proceeded through statistical analysis to compare the functional outcomes of patients in each group. RESULTS: Statistical evaluation of ALOD findings in patients from each surgical group found a significantly higher rate of high-grade ALOD in patients who underwent cervical arthrodesis with plate fixation compared with cervical arthroplasty (68.2% vs. 11.1%, P=0.0003). Functional outcomes of patients were also assessed at the 10-year mark and outcomes in patients with either high-grade or low-grade ALOD were compared. When stratified by high versus low-grade ALOD, no significant difference was found for Neck Disability Index (NDI) (P=0.6431), VAS-arm (P=0.4497), or VAS-neck (P=0.8700) scores between groups. CONCLUSIONS: The present study suggests that there are no significant long-term functional outcome differences between patients with and without significant ALOD. Our findings suggest ALOD may be a radiographic finding that does not alter patient-reported outcomes. LEVEL OF EVIDENCE: Level III-therapeutic.

The perceived efficacy and utility of spine bioskills curricula for resident and fellow education.

The purpose of this study is to assess the role of bioskills in orthopaedic and neurosurgical resident education. A survey of the utilization and perceived efficacy of bioskills was submitted to Lumbar Spine Research Society (LSRS) members. 36/104 surgeons responded, including 25 orthopaedic, 7 neurosurgical, and 4 integrated respondents. 63% of orthopaedic and 83% of neurosurgery faculty, reported using bioskills. When asked if completion of bioskills modules would encourage advancing trainees' participation (1-10 scale, 10 greatly increase), neurosurgical faculty reported 4.00 versus orthopaedics 6.43. Although orthopaedic faculty perceive greater efficacy of bioskills, the clinical impact of this difference remains uncertain.

Role of Imaging, Tissue Sampling, and Biomarkers for Diagnosis of SSI in Spine Surgery.

In July 2018, the Second International Consensus Meeting on Musculoskeletal Infection convened in Philadelphia, PA to discuss issues regarding infection in orthopedic patients and to provide consensus recommendations on these issues to practicing orthopedic surgeons. During this meeting, attending delegates divided into subspecialty groups to discuss topics specifics to their respective fields, which included the spine. At the spine subspecialty group meeting, delegates discussed and voted upon the recommendations for 63 questions regarding the prevention, diagnosis, and treatment of infection in spinal surgery. Of the 63 questions, 15 focused on the use of imaging, tissue sampling, and biomarkers in spine surgery, for which this article provides the recommendations, voting results, and rationales.